WO2014120886A1 - Solution additive plaquettaire ayant un peptide formant un hydrogel à auto-assemblage - Google Patents

Solution additive plaquettaire ayant un peptide formant un hydrogel à auto-assemblage Download PDF

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Publication number
WO2014120886A1
WO2014120886A1 PCT/US2014/013777 US2014013777W WO2014120886A1 WO 2014120886 A1 WO2014120886 A1 WO 2014120886A1 US 2014013777 W US2014013777 W US 2014013777W WO 2014120886 A1 WO2014120886 A1 WO 2014120886A1
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platelets
platelet
pas
amount
source
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PCT/US2014/013777
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English (en)
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Qiyong Peter Liu
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Velico Medical, Inc.
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Publication of WO2014120886A1 publication Critical patent/WO2014120886A1/fr

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    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N1/00—Preservation of bodies of humans or animals, or parts thereof
    • A01N1/02—Preservation of living parts
    • A01N1/0205—Chemical aspects
    • A01N1/0231—Chemically defined matrices, e.g. alginate gels, for immobilising, holding or storing cells, tissue or organs for preservation purposes; Chemically altering or fixing cells, tissue or organs, e.g. by cross-linking, for preservation purposes

Definitions

  • Platelets intended for transfusion are highly perishable. Platelets are non-nucleated bone marrow-derived blood cells that protect injured mammals from blood loss by adhering to sites of vascular injury and by promoting the formation of plasma fibrin clots. Humans depleted of circulating platelets by bone marrow failure suffer from life threatening spontaneous bleeding, and less severe deficiencies of platelets contribute to bleeding complications following trauma or surgery.
  • Platelet deficiencies associated with bone marrow disorders such as aplastic anemia, acute and chronic leukemia, metastatic cancer, and deficiencies resulting from cancer treatment such as ionizing radiation or chemotherapy all contribute to a major public health problem.
  • Patients that suffer from thrombocytopenia associated with major surgery, injury and sepsis also require significant numbers of platelet transfusions.
  • platelets collected for transfusion are highly perishable because, upon storage at or below room temperature, they quickly lose in vivo hemostatic activity.
  • Hemostatic activity of platelets broadly refers to the ability of a population of platelets to mediate bleeding cessation. Platelets, unlike all other transplantable tissues, do not tolerate refrigeration and disappear rapidly from the circulation of recipients if subjected to even very short periods of chilling.
  • the cooling effect that shortens in vivo platelet survival is thought to be irreversible and, therefore, cooled platelets become unsuitable for transfusion.
  • One of the first visible effects of platelet impairment is an irreversible conversion from a discoid morphology towards a spherical shape, and the appearance of spiny projections on the surface of platelets due to calcium dependent gelsolin activation and phosphoinositide-mediated actin polymerization. When platelets are exposed to temperatures lower than 20°C, they rapidly undergo such modifications in shape.
  • the present invention relates to a platelet additive solution (PAS) that includes an amount of one or more self-assembling hydrogel-forming peptides and optionally an amount of one or more sialidase inhibitors, one or more ⁇ -galactosidase inhibitors, one or more glycan-modifying agents, or a combination thereof; and one or more of PAS components that includes a salt (e.g., sodium source, a chloride source, a potassium source, a magnesium source, a calcium source, and a combination thereof), a citrate source (e.g., monosodium citrate, disodium citrate, trisodium citrate, citric acid, and any combination thereof), and/or a carbon source (e.g., acetate, glucose, sucrose and any combination thereof).
  • a salt e.g., sodium source, a chloride source, a potassium source, a magnesium source, a calcium source, and a combination thereof
  • a citrate source e.g., monos
  • the PAS can optionally include, either separately or together, a second platelet additive solution (PASII) that has an amount of cationic polymers.
  • Cationic polymers are defined herein as those polymers (having repeating monomers) that have a positive charge under physiological conditions. Cationic polymers include polymers that are not charged, as long as they are combined with other polymers that are positively charged.
  • An example for a cationic polymer is poly-L-lysine (PLL) coupled with polyethylene glycol (PEG), in which case the cationic polymer can be represented as PLL-g-PEG.
  • the components of the cationic polymer for example the PEG, can be derivatized, for example by converting one of the termini to have a methyl group instead of a hydroxyl group.
  • the cationic polymers disclosed herein are not intended to form covalent bonds with membrane proteins or glycoproteins of platelets.
  • the PASII can optionally have an amount of one or more sialidase inhibitors, one or more ⁇ -galactosidase inhibitors, one or more glycan-modifying agents, or a combination thereof; and one or more of PAS components that includes a salt (e.g., sodium source, a chloride source, a potassium source, a magnesium source, a calcium source, and a combination thereof), a citrate source (e.g., monosodium citrate, disodium citrate, trisodium citrate, citric acid, and any combination thereof), and/or a carbon source (e.g., acetate, glucose, sucrose and any combination thereof).
  • a salt e.g., sodium source, a chloride source, a potassium source, a magnesium source, a calcium source, and a combination thereof
  • a citrate source e.g., monosodium citrate, disodium citrate, trisodium citrate, citric acid, and any combination thereof
  • Some embodiments have both hydrogel- forming peptdies (as part of the defined PAS) and cationic polymers (as part of the defined PASII).
  • the indicated optional components can be present alongside either PAS or PASII, or alongside both PAS and PASII. Because the PAS is defined herein to optionally include PASII, the designation PAS can refer to only PAS without PASII, or to PAS having PASII as well (e.g., some embodiments of PAS include cationic polymers, whereas other embodiments do not).
  • the PAS of an embodiment of the present invention is maintained at a pH ranging between about 6.4 and about 7.6.
  • the PAS of the present invention further includes a phosphate source (e.g., sodium monophosphate, diphosphate, triphosphate, and a combination thereof).
  • An acetate source can include, for example, sodium acetate, potassium acetate, magnesium acetate, or a combination thereof.
  • the sodium source can be sodium chloride, sodium citrate, sodium acetate, sodium phosphate or a combination thereof.
  • the chloride source can be sodium chloride, magnesium chloride, potassium chloride, or a combination thereof.
  • the potassium source in an example, can be potassium chloride, potassium citrate, potassium acetate, potassium phosphate, potassium sulfate, or a combination thereof.
  • sources of magnesium include magnesium chloride, magnesium citrate, magnesium sulfate, and a combination thereof.
  • the calcium source encompasses calcium chloride, calcium acetate, calcium citrate, or a combination thereof.
  • the PAS of the present invention includes an amount of one or more self-assembling hydrogel-forming peptides and optionally an amount of one or more sialidase inhibitors, one or more ⁇ -galactosidase inhibitors, one or more glycan-modifying agents, or a combination thereof; a sodium source in an amount between about 100 mM and about 300 mM; a chloride source in an amount between about 40 mM and about 110 mM; a citrate source in an amount between about 2 mM and about 20 mM; an acetate source in an amount between about 10 mM and about 50 mM; a phosphate source in an amount between about 5 mM and about 50 mM; a potassium source in an amount between about 0.5 mM and about 10 mM; a magnesium source in an amount between about 0.5 mM and about 2.5 mM; a calcium source in an amount between about 0.5 mM and about 2.5 mM; and a glucose source in an
  • embodiments include, in addition to the listed components of PAS (some of which are optional), additional PAS components defined as PASII (e.g., cationic polymers).
  • PASII e.g., cationic polymers
  • the present invention pertains to platelet compositions having isolated platelets; the PAS of the present invention; and plasma, wherein the platelet composition is maintained at a pH ranging between about 6.4 and about 7.6.
  • the plasma is present in an amount between about 1% and about 50% by volume (e.g., between 20% and 40%> plasma, or about 30% plasma).
  • the platelet additive solution is present in an amount between about 50% and about 99% by volume.
  • the platelet compositions have PASII either as a separate solution from PAS or as a part of the same solution as PAS.
  • the present invention further relates to a bag or container suitable for platelet storage having the PAS and optionally PASII of the present invention.
  • the bag or container can further include isolated platelets and/or that can be maintained at a pH ranging between about 6.4 and about 7.6.
  • the present invention relates to a method of storing platelets, wherein isolated platelets are obtained from one or more donors.
  • the method includes the steps of contacting the isolated platelets with the PAS (optionally having PASII), described herein.
  • PAS optionally having PASII
  • Any of the compounds described herein can be used as their pharmaceutically acceptable salts.
  • Glycan modifying agents can be UDP-galactose, CMP-sialic acid, or a combination thereof.
  • the self-assembling hydrogel- forming peptide can be, for example, an oligopeptide with fewer than nine neutral and non-polar side chain-having amino acids linked to a polycyclic aromatic hydrocarbon.
  • the set of amino acids having neutral and non-polar side chains is taken to be glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, and phenylalanine.
  • the self-assembling hydrogel-forming peptide has a 2-naphthylacetyl group linked to a tripeptide at the N-terminus.
  • the tripeptide in this embodiment can be FFG, FFA, FFV, FFL, FFI, FFM, FFP, FFW, FFY, PPG, PPA, PPV, PPL, PPI, PPM, PPP, PPW, WWG, WWA, WWV, WWL, WWI, WWM, WWP, or WWW.
  • the hydrogel-forming peptide is essentially N-(2-naphthyl)acetyl- phenylalanyl-phenylalanyl-glycine.
  • This compound has the naphthyl group linked to the N-terminal phenylalanine group, and can alternatively be referred to as N-((2-naphthyl)acetyl)phenylalanyl- phenylalanyl-glycine.
  • the sialidase inhibitor can be, for example, fetuin; 2,3-dehydro-2-deoxy-N- acetylneuraminic acid (DANA); Oseltamivir (ethyl (3R,4R,5S)-5-amino-4-acetamido-3-(pentan-3- yloxy)-cyclohex-l-ene-l-carboxylate); Zanamivir ((2R,3R,4S)-4-guanidino-3-(prop-l-en-2- ylamino)-2-(( 1 R,2R)- 1 ,2,3 -trihydroxypropyl)-3 ,4-dihydro-2H-pyran-6-carboxylic acid);
  • Laninamivir ((4S,5R,6R)-5-acetamido-4-carbamimidamido-6-[(lR,2R)-3-hydroxy-2- methoxypropyl]-5,6-dihydro-4H-pyran-2-carboxylic acid); Peramivir ((lS,2S,3S,4R)-3-[(lS)-l- acetamido-2-ethyl-butyl]-4-(diaminomethylideneamino)-2-hydroxy-cyclopentane-l-carboxylic acid); any combination thereof; or a pharmaceutically acceptable salt thereof.
  • the sialidase inhibitor is the sodium salt of 2,3-dehydro-2-deoxy-N-acetylneuraminic acid.
  • the ⁇ - galactosidase inhibitor can be, e.g., 1-deoxygalactonojirimycin (DGJ); N-(n- butyl)deoxygalactonojirimycin; N-(n-nonyl)deoxygalactonojirimycin; 5-deoxy-L-arabinose;
  • galactostatin bisulfite 3',4',7-trihydroxyisoflavone; D-ribonolactone; N-octyl-4-epi-P-valienamine; phenylethyl ⁇ -D-thiogalactopyranoside; difluorotetrahydropyridothiazinone; 4-aminobenzyl 1-thio- ⁇ -D-galactopryranoside; a combination thereof; or a pharmaceutically acceptable salt thereof.
  • the method can allow isolated platelets to be stored for a period of about 1 to about 21 days.
  • the isolated platelets are stored a temperature of between about 1°C and about 25°C (e.g., about 2°C to about 24°C).
  • the method includes the steps of cooling the platelet composition to a temperature below room temperature; storing the platelet composition for a period of time; and then rewarming the platelet composition back to room temperature.
  • the population of platelets is treated with the hydrogel-forming peptide, the sialidase inhibitor, the ⁇ - galactosidase inhibitor, or a combination of the foregoing within a time period, wherein the time period is in a range between about 1 minute to about 48 hours.
  • the population of platelets is also treated with a PASII that includes one or more cationic polymers.
  • the treatment with PASII can be performed at the same time as the treatment with PAS that has hydrogel-forming peptides.
  • the treatment with PASII can follow the treatment with PAS.
  • Figs. 1 A-C are schematics depicting a sialylated platelet containing intracellular sialidase and sialidase-containing bacteria.
  • Fig. 1 A Both bacterial and platelet derived sialidases remove sialic acid from platelet surfaces, leading to the formation of platelets with impaired function (1). The released sialic acids support the proliferation of contaminating bacteria (short-dashed line and 2), which leads to platelet activation (3), formation of platelet-bacteria aggregates (3), and biofilm formation (long-dashed line and 4).
  • Fig. IB Desialylated platelets are recognized and removed from the circulation by phagocytes upon transfusion.
  • FIG. ID is a schematic depicting platelets stored in the absence or presence of self- assembling hydrogel-forming peptides (gelators).
  • A Freshly isolated platelets. The platelets are surface-decorated with abundant non-immunogenic glycoproteins and glycolipids. Platelet hydrolases such as glycosidases and proteases are confined within the cell.
  • B Stored platelets. These platelets are characterized with storage-related deterioration called the platelet storage lesion, including shape change and the exposure of neo-antigens, and have reduced recovery and survival after transfusion compared with fresh platelets.
  • C Freshly isolated platelets treated with self- assembling hydrogel-forming peptides.
  • the gelators Upon addition of a limited amount of the self-assembling peptides (gelators) [below the minimal gelation concentration (mgc)] to the platelet product, the gelators are concentrated on the platelet surface, leading to the formation of nanofibers, and subsequently a thin layer of hydrogel on the platelet surface.
  • the hydrogel layer protects, and stabilizes the platelet plasma membrane, thereby suppressing the surface expression of various intracellular hydrolases and blocking/reducing the accessibility of plasma hydrolases to the plasma surface.
  • the hydrogel layer shields the platelet surface glycocalyx, comprised of glycoproteins, glyco lipids and proteoglycans, from intracellular and extracellular hydrolases such as glycosidases (sialidases, ⁇ -galactosidase, etc.) and proteases, thereby minimize the deleterious effects (PSL) on platelets during storage.
  • PSL deleterious effects
  • D Platelets after storage with self-assembling peptides.
  • the platelets, protected with a hydrogel layer during storage, have minimal PSL and are expected to have greatly improved recovery and survival after transfusion compared with platelets stored under similar conditions in the absence of self-assembling peptides. Note that the self-assembling peptides are biodegradable and have no impact on the platelet function in vivo.
  • Fig. 2 is a bar graph showing that human platelets lose sialic acid during storage at 4°C.
  • Platelet concentrates (A: Donor A and B: Donor B) were stored at 4°C for 5 days in the absence of exogenous nucleotide sugar (a), in the presence of CMP-sialic acid (CMP-SA) and UDP-galactose (UDP-gal) (b) or UDP-gal alone (c). Sialic acid content of platelets at day 0 was set to 100%.
  • FIG. 3 (A) (B) & (C) are line graphs showing that the human platelet sialidase surface activity increases following cold storage.
  • A depicts the analysis of fresh platelets, with or without permeabilization.
  • B depicts the analysis of fresh intact platelets (Donors A and B) at pH 5 and 6.
  • C depicts the corresponding analysis of intact platelets (Donors A and B) after storage at 4°C for 5 days.
  • Fig. 4 shows immunofluoresence micrographs of fixed, non-permeabilized, resting room temperature (RT) (left panels) and refrigerated (right panels) human platelets demonstrating the presence of sialidase Neu3, but not Neul, on their surfaces. Refrigeration (48h) of platelets increases sialidase (Neul) surface fluorescence, i.e., exposure. Anti-Neul antibody was used in the upper panels. Anti-Neu3 antibody was used in the lower panels.
  • Fig. 5 shows that mouse platelet sialidase surface activity increases following 48 h cold storage and rewarming. Platelet-derived sialidase activity was measured in fluorescence
  • Fig. 6 shows that fetuin competes for sialidase surface activity during platelet storage and thus inhibits the hydrolysis of sialic acid from platelet glycans.
  • the left pair of bars represents the ⁇ -galactose exposure on fresh platelets (0) in the absence (Control) or presence of fetuin (Fetuin).
  • the right pair of bars represents the ⁇ -galactose in the absence (Control) or presence of fetuin following platelet refrigeration for 48 h.
  • Sialic acid loss, i.e., ⁇ -galactose exposure is measured by RCA I binding.
  • Fig. 7 shows that the sialidase inhibitor DANA increases mouse platelet life span in vivo.
  • the bottom line represents the control platelet life span (Control).
  • the top line represents the platelet life span upon addition of DANA (DANA).
  • Fig. 8 is a schematic that shows (A) the structure of the primary GPIba structure and O- and
  • Gaipi,4GlcNAc lactosaminoglycan/LacNAc
  • Core-1 O-glycan the Core-1 O-glycan
  • Fig. 9 shows that human platelets contain the sialidases Neul and Neu3 by Western blot analysis of total platelet lysates.
  • Fig. 10 shows that human platelets release Neul into plasma upon long-term refrigeration as analyzed by Western blot. Platelets and their corresponding plasma were analyzed at day 0 and following platelet refrigeration for 1, 2 and 5 days.
  • Fig. 11 (A) depicts the characterization of platelet glycosyltransferases (GTs).
  • GTs platelet glycosyltransferases
  • Human total platelet lysates were subjected to SDS-PAGE and were immunob lotted with monoclonal antibodies: anti-GalNAc transferases (GalNAc-T 1 , -T2, -T3), 4Gal-Transferase 1 ( 4Gal-T 1 ), and
  • sialyltransferase ST3Gal-l Platelets secrete GTs. Resting platelets were maintained at 37°C or activated via the thrombin receptor PAR-1 with 25 ⁇ TRAP, for 5 min. Maximal release was observed after 1 min. The Enzymatic Activity in counts per minute (CPM) was measured in the pelleted platelet fraction (P), or in their corresponding bathing media (M). The media was clarified at 100,000 xg for 90 min to eliminate microparticles prior to activity measurements.
  • Fig. 12 depicts that endogenous platelet sialyltransferases incorporate sialic acid into platelet surface receptors.
  • A Active human platelets' surface sialyltransferase incorporated FITC- conjugated CMP-SA (FITC-SA) into resting (dotted line) or TRAP-activated platelets. FITC alone (Control) was added to resting (dotted line) or TRAP activated platelets (solid line).
  • B shows immunoblots of lysates from resting (Rest) or TRAP-activated platelets (TRAP) treated with FITC (F), FITC-CMP-sialic acid (S), or left untreated (-) and detected with antibodies to FITC, GPIba, allb, and vWf. The blots shown are representative of two experiments. Actin is shown as a loading control.
  • Fig. 13 shows that platelets lose GPIba and GPV receptors during storage at room
  • Fig. 14 shows that inhibition of metalloprotease-mediated GPIba shedding alone does not improve mouse platelet recovery and survival.
  • CMFDA Fluorescently-labeled
  • Fig. 15 shows that sialidase-treated TACE ⁇ " 7 ⁇ 11 platelets are rapidly cleared from the circulation.
  • A Flow cytometric analysis of ⁇ -galactose exposure on glycoproteins, as detected with ECL FITC-labeled lectin is shown. Lectin binding to TACE +/+ (white bars) or TACE ⁇ 11 ⁇ 211
  • C Fresh, room temperature and fluorescently-labeled (CMFDA) TACE +/+ and TACE AZn/AZn platelets treated with a2-3,6,8,9- Sialidase (5 mU/mL) (filled symbols) or left untreated (open symbols) were infused intravenously into TACE mice (10 8 platelets/10 g of body weight).
  • Fig. 16 shows that neuraminidase treatment of platelets increases ⁇ -galactose exposure (loss of sialic acid) as measured by ECL fluorescence lectin binding.
  • Data is from flow cytometric analysis of ⁇ -galactose or ⁇ -GlcNAc exposure on platelet glycoproteins, as detected with ECL I (open bars) or s-WGA (closed bars) FITC-labeled lectins. Results have been obtained from lectin binding to fresh mouse platelets in the presence and absence of a2-3,6,8,9- Sialidase from A.
  • Fig. 17 shows the dose dependent loss of platelet GPIba and GPV receptors with increasing neuraminidase concentrations.
  • Fig. 18 shows that DANA inhibits the exposure of ⁇ -galactose by neuraminidase treatment.
  • Fig. 19 shows that DANA inhibits the loss of platelet GPIba, GPV, GPIX, and ⁇ 3 ⁇ 4 ⁇ 3 receptors induced by neuraminidase treatment.
  • Surface receptor expression (GPIba, GPV, GPIX, and ⁇ , ⁇ 3 ⁇ 4 ⁇ 3 ) was measured by flow cytometry on mouse platelets in the presence (bars hatched with negatively sloping lines) and absence (open bars) of 5 mU a2-3,6,8,9-sialidase.
  • Fig. 20 depicts a non-reduced immunoblot of total platelet lysates (INPUT), supernatants (SUPERNATANT) and the corresponding platelets ' pellet (PELLET) showing that DANA inhibits the loss of platelet GPIba induced by neuraminidase (NA) treatment. Control represents untreated samples.
  • Fig. 21 is a graph showing that addition of DANA completely rescues the in vivo recovery and survival of mouse platelets treated with neuraminidase. Control depicts the survival of non- treated fresh room temperature platelets.
  • Fig. 22 is a graph showing that platelet GPIba and GPV receptor loss during storage at room temperature is inhibited by the addition of DANA.
  • Fig. 23 is a bar graph depicting the effect of neuraminidase treatment on ⁇ -galactose exposure in the presence of 100 ⁇ metalloproteinase (MP) inhibitor GM6001. ⁇ -Galactose exposure was measured by fluorescently-labeled RCA-1 lectin binding.
  • MP metalloproteinase
  • Fig. 24 is a bar graph depicting the effect of neuraminidase treatment on platelet GPIba and GPV receptor surface expression in the presence of 100 ⁇ metalloproteinase (MP) inhibitor GM6001.
  • MP metalloproteinase
  • Fig. 25 is a bar graph depicting the effects of recombinant TACE (ADAM 17) (TACE) and recombinant TACE and DANA (TACE + DANA) on platelet GPIba and GPV receptor surface expression.
  • ADAM 17 recombinant TACE
  • TACE + DANA recombinant TACE + DANA
  • TACE metalloproteinase TACE shows that sialic acid has to be hydrolyzed from glycoproteins before the proteolysis of GPIba and GPV.
  • the receptors GPIX and ⁇ 3 ⁇ 4 ⁇ 3 were not affected by treatment with recombinant TACE (not shown).
  • Fig. 26 is a bar graph depicting the quantification of free sialic acid (FSA) in fresh platelet samples and stored samples at 4°C and RT for the indicated time points. FSA concentrations are also shown on the top of each bar graph. Note that FSA detected in RT-stored platelet samples was much higher when compared to samples stored at 4°C for equivalent time periods.
  • FSA free sialic acid
  • Fig. 27 are photographs showing the time required to detect bacteria in platelet samples (TOCD: Time of color detection) stored at 4°C or at RT in the presence or absence of the sialidase inhibitor, DANA.
  • the bacterial concentration in the test sample is inversely proportional to the onset time of color development, i.e., shorter time of color detection ⁇ higher concentration of bacteria; longer time color detection ⁇ lower concentration of bacteria.
  • Selected pictures for the analysis of Day 9 samples are shown (panels A, B and C). Bacteria were detected using an assay technology as described in Example 6.
  • Panel D is a bar graph showing the quantification of the bacterial analysis in platelet samples stored at 4°C or RT in the presence or absence of sialidase inhibitor DANA.
  • TOCD (min) was plotted against the platelet samples. Note that the time required for in RT stored samples with DANA is equivalent to 4°C stored samples, indicating that DANA inhibits bacterial growth as effectively as 4°C-storage.
  • Fig. 28 is a line graph depicting the survival of mouse platelets stored for 48h by
  • Fig. 29 is a flow cytometry analysis of fresh platelet (Fresh platelets) size and density (A) and the combined effect of DANA, sialylactose, and glucose on stabilizing RT-stored mouse platelet integrity, as judged by their size (FSC) and density (SSC).
  • FSC size and density
  • SSC density
  • Analysis of mouse platelets stored for 48hat RT in the absence (- preservatives) (B) and presence (+ preservatives) (C) of sialylactose, glucose, and DANA is shown.
  • the corresponding platelet numbers are shown below the dot plots. The concentration of the preservatives is also shown.
  • Fig. 30 (A) (B) (C) & (D) is a flow cytometry dot plot analysis of mouse platelets stored at RT for 48 h in the absence (0 mM DANA; shown in panel (A) or presence of DANA at the indicated concentrations (0.1, 1.0, 10.0 mM DANA as shown in panels (B), (C), and (D), respectively).
  • 0.1 mM DANA efficiently preserved the size and density of platelets as judged by dot plot analysis.
  • the dot plots are shown in the top panels.
  • Corresponding flow cytometry histograms of platelet counts and beads (reference) are also shown (lower panels).
  • Fig. 31 shows bar graphs depicting the cell density of S. marcescens grown for 48h in different media with or without 1 mM DANA in the wells of 96-well PVC plate (panel (A)).
  • Fig. 31 in panel B depicts biofilm formation of S. marcescens, incubated for 48h in different media with or without 1 mM DANA in the wells of 96-well PVC plate.
  • panel (B) the biofilm in each well was stained with crystal violet, and the dye was recovered and measured at 595 nm. The absorption at 595 nm (A595nm) is proportional to the bacterial cells in the biofilm.
  • Fig. 32 is a bar graph showing the differences in terminal ⁇ -galactose content on fresh platelets isolated from healthy subjects. Platelet surface terminal galactose exposure was measured by flow cytometry using the ⁇ -galactose specific lectin ECL, as depicted in the schematic drawing of lectin binding to a glycan-structure.
  • Fig. 33(Aa), (Ab),(Ac), & (Ad) and Fig. 33(B) are a flow cytometry dot plot analyses and corresponding flow cytometry histograms (depicted in Fig. 33 (Aa), (Ab),(Ac), and (Ad)) of mouse platelets stored in 30% plasma and 70% PAS (referred to as INTERSOL ® solution) by volume at RT for 48 h in the absence of additive (INTERSOL ® solution) (depicted in (Aa)), the presence of 1 mM DANA (INTERSOL ® solution + DANA) (depicted in (Ab)), 10 mM glucose (INTERSOL ® solution + Glucose) (depicted in (Ac)), and 1 mM DANA plus 10 mM glucose (INTERSOL ® solution + DANA + Glucose) (depicted in (Ad)).
  • INTERSOL ® solution by volume at RT for 48 h in the absence of additive
  • Fig. 33 (B) is a bar graph showing the percent of acquired events in the gated platelet population for the INTERSOL ® solution (depicted in (Ba)), INTERSOL ® solution with DANA (depicted in (Bb)), INTERSOL ® solution with glucose (depicted in (Be)), or INTERSOL ® solution with both glucose and DANA (depicted in (Bd)).
  • Fig. 34 is a representative flow cytometry dot plot analysis of platelets stored in the absence ((-) DANA) or presence of 0.5 mM DANA ((+) DANA) (upper panel (A)).
  • a corresponding histogram of platelet counts vs side scatter (SSC) is also shown (lower panel (B)).
  • the table represents the mean fluorescence intensity (MFl) measured in the side scatter (SSC-H (MFl)) in the absence or presence of DANA.
  • Fig. 35, panel (A) is a representative flow cytometry histogram analysis of surface P-selectin exposure after human platelet storage in plasma in the absence or presence of DANA as described in Fig. 34. P-selectin exposure was measured using a monocolonal FITC conjugated antibody to P- selectin (CD62P-FITC).
  • Fig. 35, panel (B) shows quantification of P-selectin positive platelets defined in M2 (as indicated in Fig. 35, panel (A)) and the corresponding MFL
  • Fig. 36 is a flow cytometry dot plot analysis of human platelets stored at RT for 7 days in 30% plasma and 70% PAS solution (by volume) (PASa, 7.15 mM Na 2 HP0 4 , 2.24 mM NaH 2 P0 4 , 10 mM sodium citrate, 30 mM sodium acetate, 79.2 mM NaCl, 5.0 mM KC1, and 1.5 mM MgCl 2 , pH 7.2) in the presence of 0 (A), 0.1 (B) and 0.5 (C) mM DANA.
  • the platelets are defined in 'Gl ' while the platelet microparticles are defined in 'G2'.
  • the gate statistics are shown for each dot plot.
  • Fig. 37 is a schematic showing sialidase and ⁇ -galactosidase activity and a platelet clearance mechanism.
  • Fig. 38 is a schematic showing Platelet surface ⁇ -galactose exposure determined by lectin binding. Platelets were isolated from healthy volunteers and terminal ⁇ -galactose exposure was determined by flow cytometry using 1 ⁇ g/mL FITC-conjugated RCA-1 lectin. The scheme indicates RCA-1 lectin binding to terminal galactose. Isolated platelets from healthy volunteers differ in terminal ⁇ -galactose content and this correlates with platelet ingestion by HepG2 cells in vitro.
  • Fig. 39A is a graph showing the correlation of HepG2 cells' ingestion of human platelets with ⁇ -galactose exposure, by showing the quantification of platelets recovered from HepG2 cell incubation media. Isolated human platelets were labeled with CM-Orange, added to HepG2 cells and incubated for 30 min at 37°C. The number of platelets counted before addition to HepG2 cells was set to 100% for each individual.
  • Fig. 39B is a bar graph showing the ingestion of fluorescently (CM-orange) labeled fresh platelets, as detected using flow cytometry as an increase in hepatocyte associated orange fluorescence.
  • Fig. 40 is a line graph showing platelet surface terminal ⁇ -galactose changes during platelet storage. Platelets were isolated from platelet concentrates (Blood Transfusion Service,
  • terminal ⁇ -galactose exposure was determined by flow cytometry using 1 ⁇ g/mL FITC-conjugated RCA-1 lectin. Platelet concentrates were obtained from the Blood Transfusion Service, Massachusetts General Hospital, Boston, MA, and stored at room temperature under standard blood banking conditions. Platelets were obtained and analyzed at the indicated time points. Terminal ⁇ -galactose content decreases on isolated platelet surfaces during platelet storage and correlates with ingestion by HepG2 cells.
  • Fig. 41 A is a line graph showing that the HepG2 cells ingestion of human platelets correlates with the decrease in sialic acid and ⁇ -galactose exposure. Quantification of platelets recovered from HepG2 cell incubation media is shown. Isolated human platelets were labeled with CM-Orange, added to HepG2 cells and incubated for 30 min at 37°C. The number of platelets counted before addition to HepG2 cells was set to 100% for each individual.
  • Fig. 4 IB is a line graph showing the ingestion of fluorescently labeled stored platelets, as detected using flow cytometry, as an increase in hepatocyte associated orange fluorescence.
  • Fig. 42 is a bar graph showing the analysis of platelet surface sialidase activity.
  • the enzyme activity was determined using a fluorometric assay by incubating the platelets isolated from platelet concentrates (Bag A or B), with 4-MU-NeuAc.
  • the product 4-MU can be quantified by
  • Fig. 43 is a bar graph showing the analysis of platelet surface ⁇ -galactosidase activity.
  • the enzyme activity was determined using a colorimetric assay by incubation of platelets (Bag A or B) with Ga ⁇ -pNP.
  • the product pNP can be read at 405 nm at pH > 10.
  • Donors A and B exhibited variable platelet surface ⁇ -galactosidase activity at the early stage of the storage (Day 1), which became up-regulated after further storage (Day 6).
  • Donor B has higher activity than Donor A on both Day 1 and Day 6.
  • ⁇ -Galactosidase activity on the platelet surface increases during room temperature storage.
  • Fig. 45A is a schematic showing the general structure of the self-assembling peptides.
  • F Phenylalanyl group;
  • R 4 OH, -O-alkyl group, -N-alkyl group, amino acid, lipid, glycolipid, peptide, oligopeptide, polypeptide, protein, glycoprotein, sugar, oligosaccharide or polyethylene glycol.
  • Fig. 45B is a schematic showing exemplary aromatic (R 3 ) groups used with general structure of the self-assembling peptides of Fig. 45 A.
  • Fig. 46 is a schematic showing the structural depiction of selected self-assembling peptides including Nap-peptide assemblies and Fmoc-peptide assemblies.
  • PS phosphatidylserine
  • Fig. 47B is a bar graph of platelet surface exposure of PS as measured by FITC labeled
  • PAS platelet additive solution
  • PAS replaces a portion of the plasma in which the isolated platelets are collected during apheresis.
  • PAS is a medium that is generally a physiologically compatible, aqueous electrolyte solution.
  • the PAS solution of the present invention includes one or more hydrogel-forming peptides and optionally one or more of the following: a sialidase inhibitor; a ⁇ -galactosidase inhibitor; a glycan modifying agent or any combination thereof.
  • the PAS further comprises a second platelet additive solution (PASII) either as a component of itself or as a separate solution.
  • PASII has one or more cationic polymers.
  • PASII can optionally have any of the other components of the PAS, such as a sialidase inhibitor; a ⁇ -galactosidase inhibitor; a glycan modifying agent or any combination thereof.
  • PASII can be a separate solution from PAS or it can be a part of PAS; therefore, in some embodiments, PAS includes PASII.
  • PAS solutions are used because they are believed to reduce allergic and febrile transfusion reactions associated with certain elements found in human plasma, facilitate ABO- incompatible platelet transfusions, optimize the use of pathogen inactivation techniques, and make more plasma available for other purposes (e.g., for fractionation).
  • One embodiment of the present invention includes a PAS solution having a hydrogel- forming peptide with none, either, or both of a sialidase inhibitor and a ⁇ -galactosidase inhibitor, and optionally a glycan-modifying agent. More specifically, the present invention includes a PAS composition having a hydrogel-forming peptide with or without any combination of a sialidase inhibitor, a ⁇ -galactosidase inhibitor, a glycan-modifying composition, and one or more of PAS components (e.g., salts, buffers, nutrients and any combination thereof).
  • PAS components e.g., salts, buffers, nutrients and any combination thereof.
  • PAS of the present invention can include a variety of components such as one or more salts (e.g., NaCl, KC1, CaCl 2 , MgCl 2 , and MgS0 4 ), one or more buffers (e.g., acetate, bicarbonate , citrate, or phosphate), and nutrients (e.g., acetate, gluconate, glucose, maltose, or mannitol).
  • salts e.g., NaCl, KC1, CaCl 2 , MgCl 2 , and MgS0 4
  • buffers e.g., acetate, bicarbonate , citrate, or phosphate
  • nutrients e.g., acetate, gluconate, glucose, maltose, or mannitol.
  • PAS further includes PASII.
  • PASII in addition to including one or more cationic polymers, can optionally include a sialidase inhibitor, a ⁇ -galactosidase inhibitor, a glycan-modifying composition, and one or more of PAS components (e.g., salts, buffers, nutrients and any combination thereof).
  • PAS components e.g., salts, buffers, nutrients and any combination thereof.
  • the optional inhibitors, agents, salts, buffers, nutrients, etc. of PASII can be identical to those of PAS.
  • platelet additive solution or “PAS” of the present invention refers to the solution or medium having at least one or more hydrogel-forming peptides with none, either, or both of one or more sialidase inhibitors and one or more ⁇ -galactosidase inhibitors; and one or more storage medium components, and optionally, one or more glycan modifying agents.
  • the "inventive composition” includes one or more hydrogel-forming peptides with none, either or both of one or more sialidase inhibitors and one or more ⁇ -galactosidase inhibitors; and optionally one or more glycan-modifying agents.
  • the PAS or the inventive composition in some embodiments, includes PASII (as part of PAS or as a separate solution) as well.
  • PASII as part of PAS or as a separate solution
  • platelet composition or “platelet storage composition” refers to the resulting storage composition (prior to transfusion into a recipient), which includes the PAS of the present invention, the platelets, and optionally, any plasma and/or anticoagulant associated with the platelets.
  • hydrogel-forming peptides can be used as a component of the PAS.
  • the hydrogel-forming peptides can be used either without additional inhibitors, or together with one type (sialidase inhibitors or ⁇ - galactosidase inhibitors) or both types of inhibitors (sialidase inhibitors and ⁇ -galactosidase inhibitors).
  • Hydrogel-forming peptides assemble around the platelets and the ensuing structures lead to the formation of a spherical hydrogel layer around the platelet.
  • the formed hydrogel layer decreases the accessibility to the platelet glycocalyx by various hydrolases such as sialidases, ⁇ - galactosidases and proteases, and effectively disables their deleterious hydrolytic actions to platelet surface glycans and receptors.
  • the PAS can include cationic polymers (e.g., as part of the PASII component of PAS). Cationic polymers contribute to the layering around the platelet and help further shield it from hydrolases, bacterial agents, and host immunogenicity agents.
  • the layer or layers created by the cationic polymers can be additional ones formed around the hydrogel formed by the hydrogel-forming peptides, or they can be co-existing with those formed by the hydrogel-forming peptides (e.g., hydrogel-forming peptides and cationic polymers simultaneously forming one layer to which they both contribute; or both forming layers that intermix to various degrees).
  • the medium of the PAS of the present invention includes a physiologically compatible, aqueous electrolytic solution. Such solutions can contain ionic elements in solution such as sources of sodium, potassium, magnesium, calcium, chloride, and phosphate.
  • the PAS of the present invention can also contain, e.g., sources of citrate that can be added in the form of citric acid or sodium salt.
  • the solution of the present invention further includes, for example, carbon or nutrient source, such as acetate, glucose or gluconate, and can be present in combination with a salt.
  • a phosphate source in an embodiment, can be included to help maintain ATP production.
  • These elements can be present in the solution of the present invention in an amount ranging from about 5 mM to about 450 mM (e.g., 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 450 mM).
  • the solution is maintained at a pH ranging from about 6.4 and about 7.6 (e.g., about 7.1 to about 7.4), and preferably at a pH of about 7.2.
  • a source of sodium can be present in the PAS of the present invention in an amount between about 100 and 300 mM (e.g., between about 150 mM and about 250 mM). In a particular embodiment, a source of sodium is present at about 190 mM.
  • Sodium can be present as a salt or in combination as a buffer, or carbon source.
  • sodium can be present in the form of sodium chloride (NaCl), sodium citrate, sodium acetate, sodium phosphate or a combination thereof.
  • Other suitable sources of sodium can be used in the PAS of the present invention including those known in the art or later discovered.
  • a source of chloride (CI) can also be present in the PAS of the present invention in an amount between about 40 mM and about 110 mM (e.g., between about 60 mM and about 90 mM).
  • the source of chloride is present at about 87.2 mM.
  • Chloride can be present in the form of sodium chloride (NaCl), magnesium chloride (MgCl 2 ), potassium chloride (KC1), or a combination thereof. Any source of chloride known in the art or later discovered can be used with the present invention so long as it is suitable for use with PAS of the present invention.
  • Na + and CI " mainly in the form of NaCl, are tonicity modifiers that contribute to the isotonicity of platelet additive solution.
  • a source of potassium in an embodiment, can be present in the PAS of the present invention. It can be present in an amount ranging between about 0.5 mM and about 10 mM, and for example, between about 3 mM and about 8 mM. In a particular embodiment, potassium is present in an amount of about 5 mM.
  • Potassium sources include potassium chloride, potassium citrate, potassium acetate, potassium phosphate, potassium sulfate or a combination thereof. Other sources of potassium known in the art or later discovered can be used with the present invention. The presence of potassium ion in the medium can assist, in certain aspects, in maintaining intracellular magnesium ion concentration.
  • K + plays important roles in membrane stability by contributing to the electrical continuity of lipids and proteins.
  • Magnesium is another salt that can be included in the PAS of the present invention.
  • a source of magnesium can be present in an amount ranging between about 0.5 mM and about 2.5 mM, and in particular, in an amount ranging between about 1 mM and 2 mM.
  • magnesium is present in the PAS of the present invention at about 1.5 mM.
  • Sources of magnesium include magnesium chloride, magnesium citrate, magnesium sulfate, and a combination thereof. Sources of magnesium known in the art or later discovered can be used.
  • magnesium ion can be present in the PAS of the present invention at concentrations close to plasma levels, which will be about 3 mEq/L (1.5 mM). Mg 2+ might be necessary to maintain membrane ATPase activity.
  • magnesium ion in the medium should maintain the optimal intercellular magnesium levels in the platelets and may promote oxidative phosphorylation in the platelets and in so doing help maintain the pH of the medium.
  • Mg 2+ plays important roles in membrane stability by contributing to the electrical continuity of lipids and proteins.
  • Calcium is another yet salt that can be included in the PAS of the present invention.
  • a source of calcium can be present in an amount ranging between about 0.5 mM and about 2.5 mM (e.g., between about 1 mM and 2 mM). In a certain embodiment, calcium is present in the PAS of the present invention in about 1.5 mM.
  • Sources of calcium include calcium chloride, calcium acetate, calcium citrate, or a combination thereof. Sources of calcium known in the art or later discovered can be used.
  • Citrate can be used to buffer the solution.
  • a source of citrate is present in the PAS of the present invention in an amount ranging between about 2 mM and about 20 mM, and for example, in an amount between about 5 mM and about 15 mM.
  • the PAS of the present invention includes about 10 mM of citrate.
  • citrate sources that can be used in the present invention include sodium citrate (e.g., monosodium citrate, disodium citrate, trisodium citrate), citric acid, potassium citrate, magnesium citrate and a combination thereof.
  • Other sources of citrate can be used including those known in the art or later discovered so long as it is suitable for use with PAS of the present invention.
  • Citrate plays multiple roles in PAS of the present invention as an anticoagulant, a carbon source for the TCA cycle and buffer.
  • Acetate is yet another component of the PAS of the present invention.
  • Acetate is a carbon source used as a nutrient for the isolated platelets.
  • a source of acetate can be present in an amount ranging between about 10 mM and about 50 mM, and for example, in an amount ranging between about 25 mM and about 45 mM.
  • the PAS of the present invention includes about 30 mM of acetate.
  • Sources of acetate include sodium acetate, potassium acetate, magnesium acetate, or a combination thereof. Other sources of acetate can be used including those known in the art or later discovered so long as it is suitable for use with PAS of the present invention.
  • Acetate serves as carbon and buffer.
  • a nutrient source can be provided.
  • Acetate and other carbohydrates such as glucose or sucrose, as well as citrate, can be used individually or in various combinations to provide a source of energy for platelets in storage by being a source of intermediate metabolites for the production of energy in the citric acid cycle.
  • a combination of a carbon source can be used.
  • glucose and/or sucrose the concentration can be present in an amount ranging from about 0.5 mM to about 25 mM (e.g., about 2 mM to about 22 mM).
  • oxaloacetate can be present in the PAS of the present invention or can be added to platelet suspension after the PAS of the present invention has been added to a platelet rich fraction.
  • Oxaloacetate is a four-carbon molecule found in the mitochondria that condenses with Acetyl Co-A to form the first reaction of the TCA cycle (citric acid cycle).
  • Oxaloacetate can be supplied to the stored platelets either directly or in the form of precursor amino acids such as aspartate.
  • oxaloacetate can be present in the PAS of the present invention from about 10 mM to about 45 mM. More particularly, oxaloacetate can be present in the PAS of the present invention from about 20 mM to about 40 mM, or from about 24 mM to about 36 mM, or from about 28 mM to about 33 mM.
  • Phosphate (P0 4 ) is another component that can be used in the PAS of the present invention.
  • a source of phosphate can be present in the PAS of the present invention in an amount ranging between about 5 mM and about 50 mM (e.g., between about 20 and 40 mM). In a particular embodiment, a source of phosphate is present in about 28 mM.
  • Forms of phosphate include sodium monophosphate, diphosphate, triphosphate or a combination thereof. Other sources of phosphate known in the art or discovered in the future can be used.
  • Components such as acetate, citrate and phosphate can be added in combination with one or more salts, such as the calcium, magnesium, potassium, or sodium salts or any sub-combination of these salts to balance the osmolarity of the buffered solution.
  • salts such as the calcium, magnesium, potassium, or sodium salts or any sub-combination of these salts to balance the osmolarity of the buffered solution.
  • the PAS of the present invention includes one or more hydrogel-forming peptides with none, either, or both of one or more sialidase inhibitors and one or more ⁇ - galactosidase inhibitors, and optionally, one or more glycan modifying agents.
  • Components of some embodiments are described in Table 1 :
  • a cationic polymer for example a combination of poly-L-lysine (PLL) and polyethylene glycol (PEG), forming PLL-g-PEG, can be included in the above mixture, or in a separate mixture having the same or similar components (e.g., the salts and the buffering agents) in an amount ranging from 0.001 mg/mL to 4 mg/mL (e.g., 0.5 mg/mL, 1 mg/mL).
  • the PLL-g-PEG can be prepared to have varying grafting ratios which, as an example, can be 12.5 mole% (which means 12.5% of ⁇ -amino groups of PLL was modified by PEG).
  • the molecular weight of PLL can be varied, which, as examples, can be 15 kDa, 20 kDa or 35 kDa.
  • the molecular weight of PEG can be also varied, which, as examples, can be 2 kDa or 5 kDa.
  • PEG can be functionalized with different groups such as methyl, a fluorescent group such as FITC, or peptide such as RGD.
  • PAS of the present invention as described herein can also be buffered, in an
  • amino acids by amino acids.
  • the amino acids can be used as the primary buffering agents, or can be used in conjunction with other buffering agents such as phosphate.
  • the amino acid, histidine can be used to buffer the storage solution.
  • the storage solution can contain amino acids from about 1 mM to about 7 mM, or from about 2 mM to about 5 mM.
  • the PAS disclosed herein can further include other components that promote oxidative phosphorylation.
  • An antioxidant can be added to the PAS or platelet composition of the present invention. Examples of antioxidants include glutathione, selenium, and the like.
  • the antioxidant can be present in the PAS of the present invention in an amount ranging between about 0.5 ⁇ to about 3 mM (e.g., about 1.0 ⁇ to about 2 mM).
  • glutathione, or its precursor N-acetylcysteine, and/or selenium alone or in combination can be present in the PAS in an amount between about 0.5 ⁇ to about 3 mM (e.g., about 1.0 ⁇ to about 2 mM).
  • the PAS of the present invention can further include components that assist in stabilizing membranes.
  • a phospholipid or a mixture or phospholipids can be included in the storage solution.
  • phospholipids can be present in the PAS of the present invention in an amount ranging from about 0.1 mg/mL to about 7.5 mg/mL (e.g., between about 0.25 mg/mL to about 5 mg/mL).
  • L-alpha phosphatidylcholine can be present in the PAS of the present invention in an amount between about 0.1 mg/mL to about 7.5 mg/mL (e.g., about 0.25 mg/mL to about 5 mg/mL).
  • Additional components that can be included in the PAS of the present invention are nonessential amino acids.
  • non-essential amino acids in an amount ranging from about 0.5 mM to about 14 mM can be present in the PAS (e.g., about 1.0 mM to about 10 mM).
  • L-alanine can be included in an amount ranging from about 0.5 mM to about 14 mM (e.g., about 1.0 mM to about 10 mM).
  • Unsaturated free long chain fatty acids can further be included in the PAS of the present invention.
  • the PAS described herein can contain an amount of unsaturated free long chain fatty acids in a range between about 0.05 mM and about 1.5 mM (e.g., about 0.1 mM to about 1 mM).
  • the PAS of the present invention can contain palmitic acid from about 0.05 mM to about 1.5 mM, or about 0.1 mM to about 1 mM.
  • USP United States Pharmacopeia
  • WFI water for injection
  • platelet composition refers to a composition whose total volume contains between about 1% to about 50% by volume of plasma.
  • the platelet composition in one aspect, contains less than about 50% (e.g., less than about 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%) by volume plasma.
  • the platelet storage composition of the present invention has between about 50% and about 99% (e.g., about 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%) by volume of PAS of the present invention, which contains one or more hydrogel-forming peptides with none, either, or both of one or more sialidase inhibitors and one or more ⁇ -galactosidase inhibitors, in an electrolytic solution, and also phosphate and/or buffering compounds, carbon source (s), and optionally, one or more glycan modifying agents.
  • the platelet storage composition is essentially plasma free having mostly the PAS of the present invention and platelets.
  • the PAS also includes a PASII, as described in this document.
  • the platelets generally make up about 1% by volume of the total platelet composition.
  • PAS of the present invention constitutes about 70% and the plasma constitutes about 30% of the isolated platelet solution.
  • the percentage of PAS of the present invention by volume can vary depending on its use, e.g., for transfusion into chronically anemic patients or acutely anemic patients. Hypervolemia is a concern especially in trauma patients suffering from acute anemia. Accordingly, the percentage of PAS can be modified to minimize or avoid hypervolemia.
  • the platelet composition in the PAS of the present invention can be assessed at one or more time points during storage. Assessment of the platelet content, platelet morphology, metabolism, bacterial proliferation, the extent of platelet activation, extent of lysis, or a combination thereof can be performed. Additionally, the amount of cleaved sialic acid or the amount of ⁇ -galactose exposed on the glycan molecules on the platelet surface can be determined as a measure of the platelet's likelihood to be cleared from circulation. As yet another approach, the optical densities of the bacteria in solutions can be measured, for example with a spectrophotometer. Such densities can give information about the population and growth kinetics of bacteria in solution.
  • the ⁇ -potentials (Zeta potentials) of platelets can be measured to determine their propensity to clump together.
  • Z-potentials of platelets can be measured with a Zetasizer in a suitable buffer such as PBS and the like.
  • the Z-potential is measured in the PAS of the present invention.
  • the ⁇ -potentials are measured in a buffer having a pH between 6.4 and 7.6, for example at pH 7.4.
  • the assessment of platelets, their function, and bacterial proliferation is further described herein to assess the platelets' ability to be transplanted, survive in vivo and maintain hemostasis after transfusion.
  • the PAS of the present invention allows platelets to be stored longer, and have longer circulation and maintain hemostasis after transfusion, as compared to platelets not stored in the PAS of the present invention. Storage times, circulation times, and hemostasis are also further described herein.
  • Metabolism of platelets can be assessed by measuring ATP and levels of glucose, lactate and lactate dehydrogenase (LDH). ATP measurements can be carried out using assays known in the art such as Bioluminescent assay kit (Sigma, Poole, Dorset, UK). Glucose, lactate and LDH can also be measured using assays known in the art, such as Vitros DT60 11 chemistry system (Shield,
  • the platelets use a carbon source such as acetate during metabolism to maintain ATP, a major energy carrier.
  • the PAS of the present invention can maintain a pH between about 6.4 and about 7.6, and preferably between about 7.1 to about 7.4.
  • Applicants have characterized several underlying mechanisms that account for the high susceptibility of platelets to irreversible intolerance by the recipients of transfusions and the resulting loss of platelet' s in vivo hemostatic activity. Applicants' discoveries are related to sialic acid and its role in the viability of platelets.
  • sialidase-producing bacteria desialylate plasma and platelet
  • sialioglycoconjugates to obtain nutrients such as sialic acid which supports bacterial growth and proliferation. See Fig. 1 A. Bacterial proliferation leads to biofilm formation, platelet activation and aggregation. Desialylated platelets enhance bacteria-platelet interaction and eventually are cleared from circulation via lectin-mediated mechanism (Fig. IB). Accordingly, the addition of a sialidase inhibitor prevents sialic acid from being cleaved from the platelet surface, thereby preventing platelet clearance and prolonging its survival. Also, addition of a ⁇ -galactosidase inhibitor prevents ⁇ -galactose from being cleaved from the platelet surface, which also helps to prevent platelet clearance and increase in vivo platelet survival.
  • a sialidase inhibitor inhibits the proliferation of bacteria in a platelet preparation (Fig.lC).
  • the dual sialidase inhibitor function provides a superior platelet preparation with longer survivals and reduces the chance of causing bacteria-related sepsis when transfused into a recipient at the point of care.
  • the inventive platelet compositions can retain in vivo hemostatic activity for longer durations as compared to untreated platelets.
  • the inventive platelet compositions treated with sialidase inhibitors and ⁇ -galactosidase inhibitors can be stored for prolonged periods at or below room temperature as compared to untreated platelets.
  • the platelets become more negatively charged after being coated with a thin layer of self-assembled amphiphilic peptides and are less prone to aggregation.
  • the storage of platelets according to the inventive methods extends the shelf life of platelets and helps increase the supply of platelets that remain viable for transfusion with inhibited bacterial proliferation.
  • the mechanical constraint imposed on the platelet plasma membrane and/or cytoskeleton by the hydrogel layer, filled with abundant rigid nano fibers can reduce the 'chilling' effects on platelets caused by refrigeration, which include the reorganization of the platelet plasma membrane and cytoskeleton, and disable the in vivo function of platelets.
  • Applicants' discoveries relate to hydrogel-forming peptides, sialic acid, and ⁇ - galactose and their role in protecting and preserving the viability of platelets.
  • the hydrolysis of sialic acid from the outer membrane of platelets is believed to contribute to the unique and irreversible in vivo intolerance of platelets.
  • Studies have reported that platelets lose sialic acid from membrane glycoproteins during aging and circulation, and that in vitro desialylated platelets are cleared rapidly. Loss of sialic acid exposes underlying immature glycans such as ⁇ -galactose.
  • Asialoglycoprotein (ASGP) receptors are known to mediate endocytosis of proteins, cells and particles carrying exposed ⁇ -galactose. Many cells, including hepatic macrophages and hepatocytes, express and present the ASGP receptor. Accordingly, it is believed that when endogenous sialidase enzymes cleave sialic acid residues from the platelet surface, penultimate sugars such as ⁇ -galactose are exposed on the platelet surface and platelets undergo ASGP-mediated ingestion after transfusion.
  • GlcNAc N-acetylglucosamine
  • mouse platelets stored at room temperature for 6 h lost surface sialic acid, as evidenced by flow cytometry data provided herein. See Exemplification. This loss correlated with a 30-60% loss of surface receptors GPIb and GPV, but not GPIX and integrin allbp3. Furthermore, treatment of mouse platelets with the neuraminidase (NA) substrate, fetuin, partially decreases the loss of GPIb and GPV to 10-20%.
  • sialic acid was cleaved from the platelet surface by adding a2-3,6,8-neuraminidase (NA; Vibrio cholerae) or a2-3,6,-NA (Clostridium perfringens) to mouse platelets.
  • the data described herein also show that human platelets have variable surface sialidase and ⁇ -galactosidase activities among donors, and show that both are up-regulated during platelet storage at room temperature (RT).
  • the data also show that human platelets have variable surface ⁇ - galactose exposure/sialic acid loss among individual donors.
  • platelet surface ⁇ -galactose exposure appears to peak at day 2, then decrease during further storage.
  • Platelet surface ⁇ -galactose content correlates positively with ingestion by HepG2 cells, and crosstalk with platelet surface glycosidase activities.
  • GlcNAc can be further removed, exposing the mannose residues.
  • Mannose can be readily recognized by macrophage mannose receptors, triggering immediate platelet clearance. Accordingly, inhibiting both sialidase and ⁇ - galactosidase enzyme activity prolongs platelet storage and increases in vivo survival of platelets.
  • hydrogel-forming peptides in addition to attenuating the clumping of platelets, can decrease the accessibility of terminal sialic acid and ⁇ -galactose residues by sialidase and ⁇ - galactosidase enzymes. Such accessibilities can be further decreased by the use of PASII (having a cationic polymer) as part of or in addition to PAS.
  • PASII having a cationic polymer
  • the clearance of platelets is exacerbated upon cooling. It has been discovered that cooling of human platelets causes clustering of the von Willebrand factor (vWf) receptor complex a subunit (GPIba) complexes on the platelet surface.
  • the clustering of (GPIba) complexes on the platelet surface elicits recognition by macrophage complement type three receptors ( ⁇ 2, CR3) in vitro and in vivo.
  • CR3 receptors recognize N-linked sugars with terminal ⁇ -GlcNAc on the surface of platelets, which have formed GPIba complexes, and phagocytose the platelets, clearing them from the circulation and resulting in a concomitant loss of hemostatic function.
  • capping the ⁇ - GlcNAc moieties by galactosylation prevents clearance of short-term-cooled platelets, this strategy is ineffective after prolonged refrigeration (e.g., refrigeration of platelets longer than 5 days).
  • Prolonged refrigeration further increased the density and concentration of exposed galactose residues on platelets GPIba such that hepatocytes, through Ashwell-Morell receptor (ASGP receptor or hepatic lectin) binding, become increasingly involved in platelet removal. Macrophages rapidly removed a large fraction of transfused platelets independent of their storage conditions. With prolonged platelet chilling, hepatocyte-dependent clearance further diminishes platelet recovery and survival after transfusion. Inhibition of chilled platelet clearance by both ⁇ 2 integrin and Ashwell- Morell receptors may afford a potentially simple method for storing platelets in the cold.
  • Ashwell-Morell receptor Ashwell-Morell receptor
  • sialidase enzyme activity is platelet- derived, not plasma-derived, and sialidase enzyme activity and ⁇ -galactosidase enzyme activity substantially increase on the platelet surface during the storage of platelets.
  • human platelets contain the sialidases Neul and Neu3, and release Neul into plasma at room temperature, and more so upon storage in the cold, but it is the surface Neul that is involved in the removal of surface sialic acid from glycans on the surface of platelets.
  • ⁇ -galactosidase is released from the platelet to the platelet surface, along with Neul, and is involved in the removal of ⁇ -galactose from the glycans on the surface of platelets.
  • the present invention provides platelet compositions and methods for prolonging in vivo hemostatic activity and reducing platelet clearance, wherein the platelets are obtained from a donor and treated with a hydrogel-forming peptide with either, none, or both of a sialidase inhibitor and a ⁇ -galactosidase inhibitor to counteract the effects of endogenous hydrolase activities on the platelet surface including sialidase activity and ⁇ -galactosidase activity, and bacterial-derived hydrolase activities, thereby inhibit bacterial proliferation.
  • the platelets in some embodiments, are also treated with cationic polymers.
  • compositions and methods for prolonging the storage of viable platelets such as mammalian platelets, particularly human platelets.
  • the invention also provides methods for making improved platelet compositions.
  • the present invention provides platelet compositions that have enhanced circulation properties and that retain substantially normal in vivo hemostatic activity.
  • the invention provides a novel platelet composition comprising one or more hydrogel- forming peptides with none, either, or both of one or more sialidase inhibitors and one or more ⁇ - galactosidase inhibitors.
  • the platelet compositions further include cationic polymers.
  • hydrogel-forming peptides and cationic polymers decrease the accessibility of the platelets
  • sialidase enzymes catalyze the hydrolysis of terminal sialic acid residues from host cell receptors
  • ⁇ -galactosidase enzymes catalyze the hydrolysis of ⁇ -galactose residues from the receptors.
  • hydrogel-forming peptides, cationic polymers, sialidase inhibitors and/or ⁇ - galactosidase inhibitors are used in numerous aspects of the present invention to reduce accessibility of platelet surface, reduce sialidase enzyme activity/p-galactosidase enzyme activity, prevent the hydrolysis of terminal sialic acid/p-galactose residues from platelet surface glycans, inhibit bacterial proliferation, and prolong the in vivo hemostatic activity of platelets for transfusion.
  • the present invention provides for platelet compositions and related methods to prepare, store, and preserve platelet compositions that enhance the platelet function and/or allow platelets to retain substantially normal in vivo hemostatic activity after platelets have been stored at or below room temperature.
  • Certain underlying mechanisms have been discovered that contribute to the high susceptibility of platelets to undergo irreversible intolerance or loss of platelet in vivo hemostatic activity experienced by recipients of platelet transfusions.
  • the hydrolysis of sialic acid/p-galactose residues from platelet surface glycans by sialidase/p-galactosidase enzymes contributes to the irreversible intolerance of platelets.
  • Irreversible intolerance refers to a platelet's inability to retain or return to normal platelet function survival after being subjected to temperatures below that of room temperature.
  • Platinum viability is defined as the platelet's ability to survive in vivo.
  • the present invention provides platelet compositions and methods of stabilizing the platelet; reducing surface expression of sialidase or galactosidase enzymes; inhibiting sialidase enzyme activity, ⁇ -galactosidase enzyme activity, or both; in platelets isolated from a donor and stored at or below room temperature.
  • the invention provides compositions having one or more hydrogel-forming peptides with none, either, or both of one or more sialidase inhibitors and one or more ⁇ -galactosidase inhibitors, and optionally one or more glycan-modifying agents.
  • the present invention provides compositions also having cationic polymers with none, either, or both of one or more sialidase inhibitors and one or more ⁇ -galactosidase inhibitors, and optionally one or more glycan-modifying agents.
  • the present invention in other aspects, provides methods for increasing the in vivo circulation time of platelet compositions having one or more hydrogel-forming peptides with none, either, or both of one or more sialidase inhibitors and one or more ⁇ -galactosidase inhibitors.
  • methods for increasing the circulation time of platelet compositions include a PASII having one or more cationic polymers with none, either, or both of one or more sialidase inhibitors and one or more ⁇ - galactosidase inhibitors.
  • the present invention further provides platelet compositions and methods for reduced temperature storage of platelets, which increases the storage time of the platelets, as well as methods for reducing clearance of or increasing the circulation time of a population of platelets in a mammal.
  • platelet compositions and methods for the preservation of platelets with preserved hemostatic activity as well as methods for making platelet compositions and pharmaceutical compositions thereof containing the platelet compositions and for administering the pharmaceutical compositions to a mammal to mediate hemostasis.
  • isolated means separated away from its native environment. As used herein with respect to a population of platelets, isolated refers to removing platelets from the blood of a mammal.
  • Random donor platelets are platelets isolated from whole blood donations by means of any one of several standard methods practiced by those skilled in the art, and two or more random donor platelets are subsequently pooled in a quantity sufficient to constitute a therapeutic dose prior to transfusion to a patient.
  • a single random donor platelet can also be used without pooling for pediatric patients.
  • Current standard methods include isolating random donor platelets from a buffy coat, a platelet button, platelet rich plasma, and the like.
  • Single donor platelets are platelets obtained from one donor by means of centrifugal separation in an apheresis machine in a quantity sufficient to constitute one or more therapeutic dose(s) for subsequent transfusion to a patient(s).
  • Apheresis machines used currently for the collection of single donor platelets are manufactured by companies such as Terumo BCT (Terumo Corporation), Fenwal Inc., and Haemonetics Corporation.
  • Current AABB (formerly the American Association of Blood Banks) Standards define a therapeutic dose of platelets as approximately > 3xl0 u platelets.
  • random donor platelets or single donor platelets are isolated from a donor by means of standard techniques known to one skilled in the art.
  • the isolated platelet preparation is treated with one or more sialidase inhibitors and/or glycan- modifying agents as described herein.
  • Random donor platelets are obtained from whole blood donations.
  • Whole blood can be obtained from a donor and prepared by a suitable method depending on the type of blood components desired.
  • the present invention involves isolating platelets in the form of a buffy coat, a platelet button, platelet concentrate, platelet rich plasma, and the like.
  • Whole blood is comprised of a number of components including plasma, red blood cells, platelets, white blood cells, proteins and other components. Accordingly, in addition to platelets, other components from whole blood can be isolated and prepared (e.g., red blood cells, plasma, etc.) when a unit of blood is obtained from a donor.
  • Whole blood is generally collected from a donor by venipuncture.
  • the container e.g., bag or tube
  • into which one deposits the blood can contain an anticoagulant such as a citrate or citrate dextrose based component, e.g., citrate phosphate dextrose (CPD or CP2D), citrate phosphate dextrose adenine 1 (CPDA-1).
  • an anticoagulant such as a citrate or citrate dextrose based component, e.g., citrate phosphate dextrose (CPD or CP2D), citrate phosphate dextrose adenine 1 (CPDA-1).
  • a 600 mL bag that contains 70 mL of anticoagulant is used to collect approximately 500 mL ⁇ 10% of whole blood, or 63 mL of anticoagulant is used to collect 450 mL ⁇ 10% of whole blood.
  • the whole blood collection bag often has satellite bags attached thereto to hold isolated components.
  • tubes of donor blood samples are also collected for use in performing certain required tests on each blood donation, including ABO and Rh determination, infectious disease markers testing, and the like.
  • Platelets are normally separated from whole blood and other blood components by centrifugation. Centrifuge technology allows separation of blood components by their various densities. Therefore, the liquid and cellular constituents of whole blood are separated into distinct layers as the result of centrifugation, ranging from red blood cells (RBC), the most dense, to plasma, the least dense.
  • RBC red blood cells
  • the time of centrifugation varies depending on the centrifuge and the g-force provided by the centrifuge. The amount of time of centrifugation can be determined by one of skill in the art. Companies such as Sorvall and Beckman manufacture centrifuges that can be used for this process.
  • a bag that contains a mass of RBC at its distal end and a mass of platelet rich plasma (PRP), a mixture of platelets and plasma at its proximal end, with a meniscus formed primarily by white cells in between the two layers.
  • PRP platelet rich plasma
  • the PPvP is expressed into a satellite bag, leaving the mass of RBC in the original whole blood collection bag.
  • the satellite bag containing the PRP is centrifuged again (e.g., hard spin) to separate the plasma from the platelets. Upon re-centrifugation, the platelets, because of their greater density, form a loosely aggregated cluster called a platelet button.
  • the platelet poor plasma PPP
  • the platelet concentrate consists of a volume of approximately 30 to 70 mL, and the PPP consists of a fluid volume of approximately 180 to 320 mL.
  • Each separated blood component, i.e., RBC, PPP or platelet concentrate is known as a "unit", and each is transfused separately.
  • the bag of platelet concentrate contains a minimum of 5.5 x 10 9 platelets. Units of platelet concentrate are stored at 20-24°C on mechanical rotators. Platelets not treated with the compositions of the present invention have a shelf life of about 5 days.
  • 4-6 platelet concentrate units are pooled to obtain a single therapeutic dose for transfusion to a patient.
  • the pooled platelet concentrate has about 3.0 x 10 11 platelets or more.
  • the pooled and non-pooled platelet concentrate obtained from this process comprise one form of "isolated platelets" that can be utilized in the present invention or treated with the inventive compositions described herein.
  • the bag used for pooling the platelet concentrate can have the inventive compositions described therein (e.g., hydrogel-forming peptide, sialidase inhibitor, ⁇ -galactosidase inhibitor, and/or glycan modifying agent), as further described herein.
  • the inventive composition can be added to the platelet concentrate before, after, or during pooling.
  • the inventive composition also includes PASII (having one or more cationic polymers).
  • PASII can be provided in the same bag as PAS or it can be provided in a separate bag. PASII can be added to either the rest of the PAS or the platelet concentrate before, after, or during pooling.
  • Random donor platelets may also be isolated by the "buffy coat” method generally used in Europe and Canada.
  • Whole blood is obtained, as described herein, and undergoes a hard spin centrifugation. The hard spin results in a bag having plasma as the top fraction, red blood cells as the bottom fraction, and a middle layer containing platelets and leukocytes. This middle layer is known as the buffy coat.
  • buffy coats are generally isolated and pooled by one of two methods depending on the format of the bag in which the whole blood was collected. The first method is known as the "top and bottom drain method" in which the bag into which the whole blood was collected has a top and bottom drain with one or more satellite containers attached to each end.
  • An extractor e.g., Optipress® Extractor from Fenwal presses the bag flat such that the plasma layer is drained through the top drain and the red blood cells are drained through the bottom drain.
  • the extractor is designed such that the buffy coat containing primarily platelets and leukocytes with a small volume of plasma and RBC, together comprising approximately 30 to 60 mL of fluid volume, is retained within the bag. Approximately 4-6 buffy coat units are pooled to make a therapeutic dose of platelets for transfusion to a patient.
  • individual buffy coat units are sterilely connected in a chain format often referred to as the "chain method" (e.g., the bottom drain of a bag is connected to the top drain of the next bag, and so on.).
  • a platelet additive solution or plasma can be sterilely connected to the chain and used to help rinse individual buffy coat containers as the buffy coats are transferred to the bottom pooling bag along with the platelet additive solution or plasma.
  • a second method for isolating and pooling buffy coat prepared platelets utilizes a similar whole blood collection bag as used with PRP prepared platelets. Following the isolation of the buffy coat in the whole blood as described previously, the buffy coat is separated from the whole blood by first removing the plasma into one of the attached satellite containers and transferring the buffy coat into a second attached satellite container, sometimes referred to as "milking the buffy coat" leaving the RBC in the original container. Approximately 4-6 buffy coat units are pooled to make a therapeutic dose of platelets for transfusion to a patient. In pooling, individual buffy coat units are sterilely connected and pooled into a pooling container along with a platelet additive solution or plasma.
  • the pooling bag has multiple docks (e.g., like legs of a "spider") to which the individual units are connected.
  • Each buffy coat unit is then transferred from the individual bag into the pooling bag using the platelet additive solution or plasma as a rinsing agent to help reduce platelet loss in pooling.
  • This pooling method is sometimes referred to as the "spider method” and can also be used with buffy coats prepared by top and bottom separation.
  • the pooled bag undergoes centrifugation again.
  • This centrifugation is a long, soft spin in which a fraction containing platelets and the plasma/platelet additive solution is formed at the top of the pooling bag and the remaining red blood cells and leukocytes become part of the bottom fraction.
  • a plasma expresser or extractor the top layer of platelets and plasma/platelet additive solution is transferred to another bag resulting in a therapeutic dose of platelets.
  • Single donor platelets are platelets obtained from one donor by means of centrifugal separation in an automated apheresis machine in a quantity sufficient to constitute one or more therapeutic dose(s) for subsequent transfusion to a patient(s).
  • Platelets isolated by this method are generally known as single donor platelets because a therapeutic dose can be collected from a single donor.
  • the donor's blood flows from a point of venipuncture through a sterile centrifuge in which the platelets and a certain volume of plasma are centrifugally separated and isolated, with the balance of the donor's blood being returned to the donor through the initial venipuncture or a second point of venipuncture.
  • Anticoagulant compositions can be added to the platelets or be present in the bag into which the platelets are collected.
  • Various automated apheresis devices are commercially available from companies such as Haemonetics Corporation (Braintree, MA), Terumo BCT (Lakewood, CO), Fenwal, Inc., Lake Zurich, IL, and Fresenius Kabi, Friedberg, Germany.
  • the collection of platelets by apheresis generally produces 2 platelet units, wherein each unit contains approximately 200 to 300 mL of plasma and approximately 3.5 x 10 11 platelets.
  • Single donor platelets can be stored at 20-24°C for about 5 days.
  • Apheresis collection kits often include two platelet collection bags since most apheresis machines are able to collect two units of platelets.
  • the composition of the present invention as described herein, can be included in the platelet collection bags for apheresis machines or can be added to the bag before, during or after collection of the platelets using a sterile connection technique.
  • Platelet collection bags can be manufactured with the composition of the present invention and further include additional components such as anticoagulant compositions as described herein or known in the art.
  • platelets After platelets are collected by apheresis, they can be suspended in the PAS of the present invention, as described herein.
  • the compositions and methods present invention can be used with platelets isolated by any technique known in the art or developed in the future so long as a therapeutic concentration of platelets is obtained.
  • the present invention includes bags or containers including the hydrogel-forming peptide, the sialidase inhibitor, the ⁇ -galactosidase inhibitor, and/or glycan-modifying composition, or the "inventive composition" as described herein.
  • the inventive composition further includes cationic polymers. Based on the platelet isolation process, the inventive
  • composition can be included or manufactured with various platelet collection bags.
  • Platelet collection bags can be gas permeable or made from a plastic material such as PVC material.
  • Platelet collections bags can be used in the random donor collection process or in the single donor collection process.
  • the inventive composition can be placed into the collection bag in which the platelet units are pooled; therefore, the present invention includes a pooled collection bag having the inventive composition.
  • the inventive composition can be included in apheresis platelet collection bags.
  • apheresis platelet collection bags include other components used in the apheresis process such as anticoagulant compositions.
  • the present invention allows for storage of platelets at temperatures below room temperature or at room temperature, as further described herein.
  • the methods described herein reduce or diminish the amount of C0 2 generated by the platelets during storage.
  • the present invention further provides platelet containers that are substantially non-permeable to C0 2 and/or O2, which containers are useful particularly for cold storage of platelets.
  • the containers or bags include gas permeable containers.
  • the inventive compositions can alternatively be added to the isolated platelets using a sterile technique or connection.
  • the inventive composition can be sold separately in a separate bag, container, syringe, tube, or other similar blood collection medium.
  • the composition of the present invention having a hydrogel-forming peptide, sialidase inhibitor, ⁇ -galactosidase inhibitor and/or glycan-modifying agent, as further described herein is contacted with the platelets in a closed system, e.g., a sterile, sealed platelet pack so as to avoid microbial contamination.
  • the platelets can be further contacted with cationic polymers, either simultaneously with other components or subsequent to being contacted with other components.
  • a venipuncture conduit is the only opening in the pack during platelet procurement or transfusion. Accordingly, to maintain a closed system during treatment of the platelets with the composition of the present invention, such composition is placed in a relatively small, sterile container which is attached to the platelet pack by a sterile connection tube (see e.g., U.S. Pat. No. 4,412,835, the contents of which are incorporated herein by reference).
  • the connection tube may be reversibly sealed, or have a breakable seal, as will be known to those of skill in the art.
  • the seal to the container including the composition of the present invention is opened and the composition is introduced into the platelet bag.
  • the composition of the present invention is contained in a separate container having a separate resealable connection tube to permit the sequential addition of the composition to the platelets.
  • platelets are treated with the composition of the present invention, which includes one or more hydrogel-forming peptides with none, either, or both of one or more sialidase inhibitors and one or more ⁇ -galactosidase inhibitors; and optionally one or more storage enhancing compositions such as glycan-modifying agents (e.g., monosaccharides such as arabinose, fructose, fucose, galactose, mannose, ribose, gluconic acid, galactosamine,
  • glycan-modifying agents e.g., monosaccharides such as arabinose, fructose, fucose, galactose, mannose, ribose, gluconic acid, galactosamine,
  • composition can further encompass cationic polymers.
  • the treatment with cationic polymers can be done simultaneously with the treatment with the other components or at a later step.
  • the glycan-modifying agent is UDP-galactose and/or CMP-sialic acid.
  • the composition of the present invention includes a "cocktail" in which more than one or a combination of these constituents is included. The phrase, "composition" or "inventive
  • composition refers to one or more hydrogel-forming peptides with none, either, or both of one or more sialidase inhibitors and one or more ⁇ -galactosidase inhibitors, and optionally one or more glycan-modifying agents.
  • the composition can further include one or more cationic polymers.
  • Hydrogel-forming peptides are molecules that contain a number of amino acids, and that when in contact with platelets, encapsulate the platelet, and cause the formation of a hydrogel shield around the platelet (Fig. ID, showing the alternatively labeled self-assembling peptides). Hydrogel-forming peptides can contain non amino acid residues as well, in addition to containing residues that are derivatives of amino acids. "Hydrogels,” as used herein, refer to hydrophilic networks of polymer chains in an aqueous medium, such as water. Hydrogel-forming peptides are able to self-assemble into polymers that facilitate the hydrogelation around the platelet.
  • the hydrogel-forming peptides assemble into nanofibers.
  • An example is N- (2-naphthyl)acetyl-phenylalanyl-phenylalanyl-glycine, (also referred to as "Nap-FFG”), where Nap is a 2-naphthylacetyl group, F is a phenylalanyl group, and G is glycine.
  • Nap-FFG N- (2-naphthyl)acetyl-phenylalanyl-phenylalanyl-glycine
  • Nap-FFG Nap-FFA
  • Other polycyclic aromatic hydrocarbons can be substituted for the Nap group (See Fig. 45B).
  • bulky amino acids with neutral and non-polar side chains such as proline and tryptophan can be substituted for the position of phenylalanine groups.
  • amino acids with neutral and non- polar side chains can form the oligopeptide part of the hydrogel-forming peptide (Fig. 46).
  • Examples of such amino acids are glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, and phenylalanine.
  • Enantiomers of such amino acids are also encompassed by the present invention.
  • Nap-FFG Nap- D F D FG can be used.
  • the amino acids residues can be replaced with L-amino acids, D-amino acids, peptoids, ⁇ -amino acids or a combination thereof.
  • the hydrogel-forming peptide can be represented as
  • F Phenylalanyl group
  • R 4 OH, -O-alkyl group, -N-alkyl group, amino acid, lipid, glycolipid, peptide, oligopeptide, polypeptide, protein, glycoprotein, sugar, oligosaccharide or polyethylene glycol (Fig. 45 A).
  • R 3 can be linked to the phenylalanine through a variety of linkages including carbonyls, esters, amides, acyls, carboxamides, and the like. Additional linkages include alkyl, akenyl, alkynyl, carbamoyl, amino, ammonio, imino, imido, azo, cyanato, isocyanato, nitroxy, nitrosooxy, nitro, nitroso, sulfanyl, disulfanyl, sulfmyl, sulfonyl, sulfino, sulfo, thiosyanato, isothiocyanato, thioyl, phosphanyl, phoshpono, phosphonooxy, formyl, carboxy, methoxy, peroxy, alkoxy groups.
  • the present invention includes a h drogel-forming peptide with the following structure:
  • the terminal carboxylic acid group is neutralized, for example by the use of sodium carbonate.
  • Other amino acids such as unnatural ones can be substituted as well.
  • one or more amino acids constituting the hydrogel-forming peptide are modified, for example by hydroxylation, methylation, acylation, alkylation, amidation,
  • glycosylation iodination, oxidation, phosphorylation, nitrosylation, succinylation, or sulfation.
  • hydrogel Even though the peptides are hydrophobic, the resulting shell of hydrogel is hydrophilic.
  • oligopeptides can be isolated from a natural source, genetically engineered, or chemically prepared.
  • the hydrogel-forming peptide can have more than three amino acids.
  • the aromatic group can be an amino acid such as tryptophan or an aromatic group such as quinoline, isoquinoline, acridine, quinoxaline, benzimidazole, purine, imidazole, quinazoline, cinnoline, benzofuran, indole, isoindole, benzothiophene, benzoxazole, benzisoxazole, benzthiazole, naphthalene, anthracene, acridine, phthalazine.
  • the aromatic group does not have to be polycyclic; for example, it can be 4-aminobenzoic acid (PABA).
  • a potential hydrogel- forming peptide would be PABA-FF.
  • Alternative aromatic groups known now or discovered in the future, can be used as well. Some groups may be unsuitable for use with platelets if they display toxicity. Even if not harmful when conjugated to amino acids, the potential of having a fractional amount of free aromatic groups might deter their use.
  • An exemplary aromatic group that is toxic is cinnoline.
  • some aromatic groups are known to intercalate DNA; thus, proper consideration should be given to whether such properties would outweigh the benefits conferred by the hydrogel-forming peptides.
  • Some of the known DNA intercalators include acridine and anthracene.
  • hydrogel-forming peptides can be chosen so that they would assemble and/or disassemble upon a certain trigger.
  • the trigger to cause a change in the assembly state of the hydrogel can be pH, temperature, ionic strength, heat, light, or a biological agent such as an enzyme.
  • hydrogels can be disassembled by sonication before being reassembled. This can be one way of mixing platelets with hydrogel-forming peptides (e.g., preparing a first platelet preparation and a second separate hydrogel-forming peptide solution;
  • hydrogel-forming peptides can be sequentially added to a platelet preparation.
  • hydrogel-forming peptides and the platelets can be mixed directly in one step.
  • hydrogel-forming peptides can be incubated in a buffer (e.g., PBS buffer after mixing with sodium carbonate to neutralize negative charges), then heated (e.g., to 80°C), and allowed to cool to room temperature before use with platelets.
  • Gelation kinetics e.g., how fast the hydrogels form
  • hydrogel-forming peptides can be enzymatically degradable, for example to facilitate their removal once they are no longer needed.
  • the oligopeptide sequence DEVDGGG can de cleaved by the caspase CASP3.
  • Such an oligopeptide can be synthesized and used in the form of Acetyl-DEVDGGG-EDA-Fmoc, where EDA-Fmoc is fluorenylmethyloxycarbonyl ethylenediamine.
  • a typical procedure to prepare a hydrogel-forming peptide would entail synthesis (e.g., via solid state peptide sytnesis), conjugation to desired units (e.g., via optimized Fmoc chemistry), isolation of the product (e.g., via chromatographic techniques), and assessment of its properties (e.g., via High Performance Liquid Chromatography (HPLC), Mass Spectrometry (MS), Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM), Dynamic Light Scattering (DLS), and negative stain as well as cryogenic TEM).
  • HPLC High Performance Liquid Chromatography
  • MS Mass Spectrometry
  • TEM Transmission Electron Microscopy
  • AFM Atomic Force Microscopy
  • DLS Dynamic Light Scattering
  • negative stain as well as cryogenic TEM
  • hydrogel-forming peptides can have fewer than three amino acids.
  • N-(9- fluorenylmethyloxycarbonyl)phenylalanine (Fmoc-F) N-(2-naphthyl)acetyl-phenylalanine (Nap-F), N-(2-naphthol)acetyl-phenylalanine, N-(cinnamoyl)phenylalanine, Fmoc-FF, Fmoc-Y-OH
  • standard single letter codes for the amino acids are used, for example "Y" in the last molecule stands for tyrosine.
  • hydrogel-forming peptides with more amino acid residues include Nap-FFGRGD; sequences having the coiled coil forming seven amino acid abcdefg motif, where a and d are hydrophobic, and e and g are charged amino acids; and sequences tending to form beta-sheet structures such as (VK) 4 -V D PPT-(KV) 4 -NH 2 , VKVKVKVK-V D PPT-KVEVKVKV-NH 2 ,
  • hydrogel-forming peptides exist that are, for example, elastin-like (e.g., VPGXG, where X is any amino acid other than proline, (VPGVG) m (VPGXG) n , where m and n refer to the number of repeats of the blocks, GVGVP, MGLDGSMG(VPGIG) 40 VPLE, and combinations of the blocks thereof) or silk like (e.g., GAGAGS).
  • Some embodiments of hydrogel-forming peptides can have blocks of multiple types of oligopeptides (e.g., silk-like and elastin-like).
  • blocks of poly-amino acids are mixed together (e.g., K x L y , where x is the number of Lysine residues and y is the number of Leucine residues; K x L y K z , similarly, with z denoting the number of lysine residues in the third block; alternatively, instead of a block from lysine (K), a block from aspartic acid (D), glutamic acid (E), or arginine (R), and instead of a block from leucine (L), a block from valine (V), or similar amino acids can be used).
  • K lysine
  • D aspartic acid
  • E glutamic acid
  • R arginine
  • L leucine
  • V valine
  • acetyl- WKVKVKVKVK-amide and acetyl-EWEVEVEV-amide can be mixed to trigger gelation.
  • Another peptide that has potential for preventing platelet aggregation has the sequence Pro-Ser-Nva- Gly-Asp-Trp, where Nva stands for norvaline.
  • Nva stands for norvaline.
  • hydrogels can be formed by the use of proteins such as collagen (or gelatin), the use of smaller oligopeptide based hydrogels as described above can be more cost effective.
  • potential cytotoxicity of the peptides should be taken into consideration.
  • oligopeptides with amino acid sequences NFGAIL, NFGAILSS, DFNKF, DFNK, and NFGSVQ might self-assemble into fibrillar nanostructures; however, these peptides can be amyloid forming. Therefore, depending on the tissues in concern, their use might not be safe.
  • use of those peptides that are known to be capable of pore-forming might not be safe due to potential toxicity toward the platelets, and potentially toward other biological entities depending on the treatment method, dilution level prior to platelet transfusion, and existence and type of purification before platelet administration.
  • hydrogels In addition to their biofunctionality, considerations for the choice of hydrogels include their biodegradability and their biocompatibility. In some embodiments, these criteria can be loosened, especially if a purification step is introduced between the treatment of platelets with hydrogel-forming peptides and the administration of the platelets into a recipient. Instead of or in addition to purifying the platelets (e.g., removing hydrogel-forming peptides), the hydrogel-forming peptides can be cleaved and/or diluted before administration.
  • some hydrogels have the property of undergoing shear-thinning during administration (e.g., through a syringe), which is accompanied by a transition from a gel state to a liquid state.
  • peptides described herein can assemble into varying structures such as nanotubes, nanotapes and nanofibrils.
  • the assembled hydrogels e.g., from nanofibrils
  • the physical (non-covalent) interactions can include hydrogen bonds, ⁇ - ⁇ stacking, van der Walls interacions, hydrophobic forces, electrostatic interactions (including dipole-dipole interactions), and steric forces.
  • hydrogel-forming peptides can have an alkyl chain attached to them.
  • any of the residues or components of the hydrogel-forming peptides can be further functionalized
  • platelets are first coated with a hydrogel by the use of hydrogel- forming peptides, and then they are coated with a second layer by the use of a chemical polymer molecule (i.e., a polymer).
  • a chemical polymer molecule i.e., a polymer.
  • An exemplary polymer that can be used for this purpose is polyethylene glycol (PEG).
  • PEG polyethylene glycol
  • the polymer creates a second layer around the layer of hydrogel, while in others, the polymer molecules are embedded in the hydrogel layer.
  • the degree to which the polymers can intersect with the hydrogel varies; in some embodiments, the polymers can enhance the hydrogel layer by attracting additional water molecules.
  • the polymer is specifically a "cationic polymer".
  • the cationic polymer as defined herein, possesses a net positive charge, but need not possess this charge uniformly (for example it can have a chain with no net charge covalently linked to another chain that has a net positive charge).
  • PLL-g-PEG which has multiple (potentially derivatized) PEG molecules covalently linked (potentially via linkers) to the ⁇ -amines of the lysine residues of PLL.
  • the platelets are first incubated with the hydrogel-forming peptides, and after an incubation period (e.g., 30 min, lhr, 2hr), incubated with the polymers (e.g., a cationic polymer), and then washed.
  • the washing step can be replaced with a dilution step or eliminated altogether (e.g., for polymers that are linked to a positively charged compound).
  • the mixing can be done manually or by use of an automated mixing instrument.
  • Routine laboratory techniques such as filtration, dialysis, HPLC, MS, NMR, FACS, Zeta-potential measurements, thromboelastography, etc. can be used during these protocols, either to enhance the method or to simply monitor/verify progress of certain steps.
  • platelets can be further stored (e.g., at 4°C, at room temperature) or used as described elsewhere in this document.
  • the polymer for example PEG
  • PEG can be added to platelets that are within a sample of platelet rich plasma (PRP).
  • the platelets can be washed to remove plasma components, such as plasma proteins, that would interact with PEG.
  • PEG can be mixed with platelets without needing any such washing step.
  • a cationic polymer e.g., PLL-g-PEG
  • PLL-g-PEG might have some affinity toward plasma components due to the enhanced negative charge of a hydrogel around platelets, it would be more likely to bind around platelets than to plasma proteins.
  • the process can be easily optimized as desired. For example, a minimal concentration of PEG that masks (e.g., prevents binding of antibodies to cell surface markers of platelets) platelet membrane proteins can be determined via common laboratory techniques.
  • PEG methoxy-poly(ethylene glycol)
  • mPEG methoxy-poly(ethylene glycol)
  • PEG can be derivatized in one of its end groups to link it to another molecule, such as one or more amino acid residues (e.g., Trp) or one or more hydrophobic groups (e.g., naphthalene, Fmoc, PABA).
  • Trp amino acid residues
  • hydrophobic groups e.g., naphthalene, Fmoc, PABA.
  • PEG or PEG derivative molecules with various degrees of branching can be used. These modification can be made to the PEG component of PLL-g-PEG as well.
  • the linkage type between PLL and PEG can be modififed, and the grafting ratio (percentage of amine functions of PLL modified by PEG) can be varied as well.
  • polymers can be made to react with various platelet structures, in the embodiments disclosed herein, the polymers do not form covalent bonds with the platelets (e.g., instead, they exploit hydrophobic interactions).
  • camouflage e.g., molecular shield
  • unwanted platelet aggregation is reduced, and further, due to reduced aggregation resulting in increased uniformity in distribution within solution, detection protocols will result in fewer false negatives and positives.
  • PLL-g-PEG copolymers can be synthesized in a number of ways.
  • Poly (L- lysince) hydrobromide PLL-HBr, MW 20 kDa: Sigma, St. Louise MO
  • PLL-HBr Poly (L- lysince) hydrobromide
  • PLL-HBr MW 20 kDa: Sigma, St. Louise MO
  • the N-hydroxysuccinimidyl ester of methoxypoly(ethylene glycol)propionic acid (SPA- PEG: Shearwater Polymers, Inc., Huntsville, AL) can be then added to the dissolved PLL-Hbr.
  • the reaction can proceed for about 6 h at room temperature, after which the reaction mixture can be dialyzed (SpectraPor, MW cutoff size 6-8 kDa, Spectrum, Houston, TX) against deionized water for 48 h.
  • the product can then be freeze-dried and stored at -20°C.
  • Variation of molecular weight, amount of starting material, and control of the reaction progress can produce a series of PLL-g-PEG graft copolymers of varying PEG side-change length and grafting ratios. See Spencer , Nicholas D. "Tailoring Surfaces: Modifying Surface Composition and Structure for Applications in Tribology, Biology and Catalysis" World Scientific Publishing Company; 1 edition pp208 (March 8, 2011).
  • Coating of platelets with one or more layers reduces potential immune responses that can be launched against the platelets, at least due to decreased recognition of platelet immunogenicity epitopes. While a first layer of hydrogel already reduces aggregation of platelets by increasing the net negative charge around them, addition of further layers around the hydrogel makes it even less likely for platelets to aggregate or lose their physiological capabilities. In one embodiment, more than two layers can be added. The successive layers can have alternating dominant charges (e.g., first one with hydrogel being predominantly negative, the second one with a cationic polymer having a relatively positive charge, the third layer being relatively negative, etc.).
  • PEG poly-L-lysine
  • PLL-g-PEG poly-L-lysine
  • charged layers can be constructed from alginate (AL) and chitosan-graft-phosphorylcholine (CH-PC), thereby creating layers of AL/CH-PC.
  • AL and PLL-g- PEG creating AL/PLL-g-PEG layers.
  • the platelets are covered with a first layer of hydrogel created by hydrogel-forming peptides and a subsequent layer created by PLL-g- PEG.
  • a layer of AL can be further added to the PLL-g-PEG layer.
  • a layer as being formed by one type of molecule or by two types of molecule is purely for convenience and is not intended to be definitive (e.g., hydrogel-forming peptides and PLL-g- PEG might form a layer that can be referred to as "one layer", or we can refer to an individual layer of PLL-g-PEG only, etc. to the degree that it is possible to envision the layers separately, even in an abstract way).
  • the platelet surface and thus the glycans on the platelet surface, become more stable because they are anchored by the hydrogel.
  • the platelet surface molecules become less accessible to various enzymes, including to the sialidases and ⁇ -galactosidases.
  • such formations make the ⁇ -potentials of platelets more negative, essentially making clumping of the glycan molecules less likely.
  • platelets remain stable in PAS of the present invention for a longer time period, as compared to the platelets not in PAS of the present invention.
  • the hydrogel-forming peptides can be biologically degraded by the cell, and/or cleared by the human body, and as such, they do not pose a risk of toxicity.
  • sialidase enzymes are glycoside hydrolase enzymes that cleave the glycosidic linkages of neuraminic acids. Sialidase enzymes catalyze the hydrolysis of terminal sialic acid residues from platelet surface glycans. See Fig. 8. Thus, sialidase inhibitors are used in several aspects of the present invention. Sialidase inhibitors reduce sialidase enzyme activity, prevent the hydrolysis of terminal sialic acid residues from platelet surface glycans, preserve the integrity of platelet surface glycans, and/or maintain the function of platelets that are stored prior to transfusion.
  • ⁇ -Galactosidase enzymes are glycoside hydrolase enzymes that cleave the glycosidic linkages between sialic acid and ⁇ -galactose. ⁇ -galactosidase enzymes catalyze the hydrolysis of ⁇ -galactose residues from platelet surface glycans.
  • ⁇ -galactosidase enzymes inhibitors are used in several aspects of the present invention, ⁇ -galactosidase inhibitors reduce ⁇ - galactosidase enzyme activity, prevent the hydrolysis of ⁇ -galactose residues from platelet surface glycans, assists in preserving the integrity of platelet surface glycans, and/or maintain the function of platelets that are stored prior to transfusion.
  • Sialidase/neuraminidase enzymes are a large family, found in a range of organisms.
  • Neuraminidase enzymes are glycoside hydrolase enzymes (EC 3.2.1.18) that cleave the glycosidic linkages of neuraminic acids.
  • a commonly known neuraminidase is a viral neuraminidase, a drug target for the prevention of influenza infection.
  • Other homologs are found in mammalian cells, and at least four mammalian sialidase homologs have been described in the human genome [e.g., Neul (Uniprot accession numbers: Q5JQI0, Q99519), Neu2 (Q9Y3R4), Neu3 (Q9UQ49.1), and Neu4 (A8K056, B3KR54, Q8WWR8).
  • ⁇ -Galactosidase enzymes catalyze the hydrolysis of ⁇ -galactosides into monosaccharides.
  • Substrates of different ⁇ -galactosidases include ⁇ -galactose, ganglioside GM1, lactosylceramides, lactose, and various glycoproteins.
  • ⁇ -Galactosidase is generally an exoglycosidase which hydrolyzes the ⁇ -glycosidic bond formed between a galactose and its organic moiety.
  • sialidase inhibitor can be any compound, small molecule, peptide, protein, aptamer, ribozyme, RNAi, or antisense oligonucleotide and the like.
  • inhibitor means to interfere with the binding or activity of an enzyme. Inhibition can be partial or total, resulting in a reduction or modulation in the activity of the enzyme as detected.
  • a sialidase or neuraminidase inhibitor ⁇ -galactosidase inhibitor according to the invention can be a protein, such as an antibody (monoclonal, polyclonal, humanized, and the like), or a binding fragment thereof, directed against a neuraminidase protein.
  • An antibody fragment can be a form of an antibody other than the full-length form and includes portions or components that exist within full-length antibodies, in addition to antibody fragments that have been engineered.
  • Antibody fragments can include, but are not limited to, single chain Fv (scFv), diabodies, Fv, and (Fab') 2 , triabodies, Fc, Fab, CDR1, CDR2, CDR3, combinations of CDR's, variable regions, tetrabodies, bifunctional hybrid antibodies, framework regions, constant regions, and the like (see, Maynard et al., (2000) Ann. Rev. Biomed. Eng. 2:339-76; Hudson (1998) Curr. Opin. Biotechnol. 9:395-402).
  • Antibodies can be obtained commercially, custom generated, or synthesized against an antigen of interest according to methods established in the art (Janeway et al., (2001)
  • a sialidase or neuraminidase inhibitor/p-galactosidase inhibitor can be a non- antibody peptide or polypeptide that binds a neuraminidase/galactosidase (e.g., a bacterial neuraminidase or bacterial galactosidase).
  • a peptide or polypeptide can be a portion of a protein molecule of interest other than the full-length form, and includes peptides that are smaller constituents that exist within the full-length amino acid sequence of a protein molecule of interest.
  • peptides can be obtained commercially or synthesized via liquid phase or solid phase synthesis methods (Atherton et ah, (1989) Solid Phase Peptide Synthesis: a Practical Approach. IRL Press, Oxford, England).
  • the peptide or protein-related sialidase or neuraminidase inhibitors/ ⁇ - galactosidase inhibitors can be isolated from a natural source, genetically engineered or chemically prepared.
  • the type and source of the ⁇ -galactosidase inhibitor in embodiments that also have a sialidase inhibitor, can be same, similar, or different from those of the sialidase inhibitor. These methods are well known in the art.
  • a sialidase or neuraminidase inhibitor/p-galactosidase inhibitor can also be a small molecule that binds to a neuraminidase and disrupts its function.
  • Small molecules are a diverse group of synthetic and natural substances generally having low molecular weights. They are isolated from natural sources (for example, plants, fungi, microbes and the like), are obtained commercially and/or available as libraries or collections, or synthesized.
  • Candidate sialidase or neuraminidase inhibitor/p-galactosidase inhibitor small molecules can be identified via in silico screening, fragment based drug discovery (FBDD), or high-through-put (HTP) screening of combinatorial libraries.
  • FBDD fragment based drug discovery
  • HTP high-through-put
  • a small-molecule sialidase/neuramindase inhibitor is the sodium salt of 2,3-dehydro-2-deoxy-N-acetylneuraminic acid (DANA).
  • the sialidase/neuraminidase inhibitor can also be an FDA approved viral sialidase/neuraminidase inhibitor, such as the viral sialidase/neuraminidase inhibitor oseltamivir also known as ethyl (3R,4R,5S)-5-amino-4-acetamido-3-(pentan-3-yloxy)-cyclohex-l- ene-l-carboxylate (Tamiflu, Genentech, Cambridge, Massachusetts), zanamivir also known as ((2R,3R,4S)-4-guanidino-3-(prop-l-en-2-ylamino)-2-((lR,2R)-l,2,3-trihydroxypropyl)-3,4-dihydro- 2H-pyran-6-carboxylic acid) (Relenza; Glaxo Smith Kline, Research Triangle Park, N.C.); and Peramivir ((lS,2S,3S,
  • the viral sialidase/neuraminidase inhibitor, oseltamivir is an ethyl ester prodrug that can be purchased from Roche Laboratories (Nutley, N.J.).
  • Amino acid sequences of FDA approved viral sialidase/neuraminidase inhibitors may also be derivatized, for example, bearing modifications other than insertion, deletion, or substitution of amino acid residues, thus resulting in a variation of the original product (a variant). These modifications can be covalent in nature, and include for example, chemical bonding with lipids, other organic moieties, inorganic moieties, and polymers.
  • a "sialidase inhibitor” includes, but is not limited to one or more of the following: fetuin; 2,3-dehydro-2-deoxy-N-acetylneuraminic acid (DANA); Oseltamivir (ethyl (3R,4R,5S)-5-amino-4-acetamido-3-(pentan-3-yloxy)-cyclohex-l-ene-l-carboxylate); Zanamivir
  • sialidase inhibitor is the sodium salt of 2,3-dehydro-2-deoxy-N-acetylneuraminic acid or a combination thereof.
  • Sialidase inhibitors used with the present invention include those known in the art or those later developed.
  • a " ⁇ -galactosidase inhibitor” includes, but is not limited to one or more of the following: 1-deoxygalactonojirimycin (DGJ); N-(n-butyl) deoxygalactonojirimycin; N-(n- nonyl)deoxygalactonojirimycin; 5-deoxy-L-arabinose; galactostatin bisulfite; 3',4',7- trihydroxyisoflavone; D-ribonolactone; N-octyl-4-epi-P-valienamine; phenylethyl ⁇ -D- thiogalactopyranoside; difluorotetrahydropyridothiazinone; and 4-aminobenzyl l-thio-P-D- galactopryranoside; or a pharmaceutically acceptable salt thereof.
  • DGJ 1-deoxygalactonojirimycin
  • N-(n-butyl) deoxygalactonojirimycin N-
  • the ⁇ -galactosidase inhibitor is the 1-deoxygalactonojirimycin (DGJ).
  • DGJ 1-deoxygalactonojirimycin
  • ⁇ -galactosidase inhibitors used with the present invention include those known in the art or those later developed.
  • glycan or “glycan residue” is a polysaccharide moiety on the surface of the platelet, exemplified by the GPIba polysaccharide.
  • a "terminal" glycan residue is the monosaccharide/sugar residue at the terminus of the polysaccharide chain, which typically is attached to polypeptides on the platelet surface.
  • a glycan-modifying agent includes an agent that modifies glycan residues on the platelet. The glycan-modifying agent repairs cleavage that occurs on the glycan residue. In an embodiment, the glycan-modifying agent alters the sugar residues of the polysaccharide chain of GPIba on the surface of the platelet.
  • hydrogel-forming peptides, cationic polymers, sialidase inhibitors and ⁇ - galactosidase inhibitors serve to preserve the integrity of the glycan structures, and specifically the glycan termini
  • the glycan-modifying agents serve to modify or repair glycans by the addition of monosaccharide(s) to the glycan.
  • hydrogel-forming peptides/cationic polymers/sialidase inhibitors/p-galactosidase inhibitors and glycan-modifying agents serve distinct and complementary functions.
  • Glycan-modifying agents include monosaccharides such as arabinose, fructose, fucose, galactose, mannose, ribose, gluconic acid, galactosamine, glucosamine, N- acetylgalactosamine, muramic acid, sialic acid (N-acetylneuraminic acid), and nucleotide sugars such as cytidine monophospho-N-acetylneuraminic acid (CMP-sialic acid), uridine diphosphate galactose (UDP-galactose), and UDP-galactose precursors such as UDP-glucose.
  • monosaccharides such as arabinose, fructose, fucose, galactose, mannose, ribose, gluconic acid, galactosamine, glucosamine, N- acetylgalactosamine, muramic acid, sialic
  • Glycan-modifying agents include precursors of CMP-sialic acid or UDP-galactose.
  • the glycan-modifying agent is UDP-galactose or CMP-sialic acid, or both.
  • UDP-galactose is an intermediate in galactose metabolism, formed by the enzyme UDP- glucose-a-D-galactose-1 -phosphate uridylyltransferase, which catalyzes the release of glucose- 1- phosphate from UDP-glucose in exchange for galactose- 1 -phosphate to make UDP-galactose.
  • UDP- galactose and sialic acid are available from several commercial suppliers such as Sigma.
  • methods for synthesis and production of UDP-galactose are known in the art and described in the literature (see for example, Liu et al., ChemBioChem 3, 348-355, 2002; Heidlas et al., J.
  • UDP- galactose precursors are molecules, compounds, or intermediate compounds that may be converted ⁇ e.g., enzymatically or biochemically) to UDP-galactose.
  • UDP-galactose precursor is UDP-glucose.
  • an enzyme that converts a UDP- galactose precursor to UDP-galactose is added to a reaction mixture ⁇ e.g., in a platelet container).
  • the glycan-modifying agent is CMP-sialic acid or a CMP-sialic acid precursor.
  • the platelet compositions comprising a CMP-sialic acid precursor further comprise an enzyme that converts the CMP-sialic acid precursor to CMP-sialic acid.
  • the glycan-modifying agent is CMP-sialic acid.
  • the glycan-modifying agent is UDP-galactose.
  • the glycan-modifying agents are CMP-sialic acid and UDP-galactose.
  • the sialidase inhibitor or the ⁇ -galactosidase inhibitor is a protein.
  • the sialidase inhibitor/p-galactosidase inhibitor is an antibody directed against a neuraminidase or ⁇ -galactosidase protein wherein the antibody is monoclonal, polyclonal, humanized, or a binding fragment thereof.
  • the methods comprising a sialidase inhibitor/p-galactosidase inhibitor that is a protein or an antibody further comprise an effective amount of at least one glycan-modifying agent.
  • the nature, source, and other properties of the ⁇ -galactosidase can be the same, similar, or different from those of the sialidase inhibitor, for embodiments in which a sialidase inhibitor is included.
  • the glycan-modifying agent is CMP-sialic acid or a CMP-sialic acid precursor.
  • the CMP-sialic acid precursor further comprises an enzyme that converts the CMP-sialic acid precursor to CMP-sialic acid.
  • the glycan-modifying agent is UDP-galactose.
  • the glycan-modifying agents are CMP-sialic acid and UDP-galactose. Treating Platelets
  • the isolated platelets are treated by the composition of the present invention. Briefly, the overall process is described as follows. Within a time period of being isolated, the composition of the present invention is contacted with the isolated platelets to thereby obtain a treated platelet composition (e.g., referred to herein as a "platelet composition").
  • the platelet composition can be stored either at room temperature or in cold temperature and then warmed.
  • the platelet composition is transfused into an individual in need of platelets and, as a result of the treatment with the inventive compositions, the transfused platelets exhibit reduced bacterial proliferation and in vivo remain in circulation longer, and maintain hemostasis longer, as compared to untreated platelets.
  • the platelet composition includes one or more hydrogel-forming peptides with none, either, or both of one or more sialidase inhibitors and one or more ⁇ -galactosidase inhibitors as described herein.
  • Nap-FFG is used as the hydrogel-forming peptide.
  • DANA is used as the sialidase inhibitor.
  • DGJ is used as the ⁇ -galactosidase inhibitor.
  • any of the following, alone or in combination, can be added: one or more sialidase inhibitors, one or more ⁇ - galactosidase inhibitors, and/or one or more of the glycan-modifying agents, such as UDP-galactose and/or CMP-sialic acid.
  • cationic polymers are also used as part of the platelet composition. The cationic polymers can be added simultaneously with the other components or separately from them.
  • the platelets are treated with the composition of the present invention.
  • the composition of the present invention is contacted with the isolated platelets in an amount that decreases probability of undesired clumping, reduces sialidase activity/p-galactosidase activity, inhibits bacterial proliferation, allows platelets to maintain hemostasis, and/or allows platelets to retain the ability to activate and form a clot.
  • an effective amount of either a hydrogel-forming peptide or a hydrogel-forming peptide in combination with one or more sialidase inhibitors and/or one or more ⁇ -galactosidase inhibitors and/or one or more glycan-modifying agents, or a hydrogel- forming peptide in combination with a cationic polymer with optional components is that amount that preserves or alters a sufficient number of glycan residues on the surface of platelets, such that when introduced to a population of platelets, reduces sialidase activity/p-galactosidase activity, inhibits bacterial proliferation, and/or increases circulation time of platelets or reduces the clearance of the population of platelets in a mammal following transfusion of the platelets into the mammal.
  • an "effective amount" of either a hydrogel-forming peptide, a sialidase inhibitor, a ⁇ -galactosidase inhibitor, and/or a glycan-modifying agent to contact with isolated platelets ranges from about 1 micromolar to about 2,000 micromolar, and most preferably about 200 micromolar to about 1.2 miUimolar (e.g., between about 1 and 10 micromolar, about 1 and about 100 micromolar, about 100 and about 500 micromolar, about 500 micromolar and about 1.0 miUimolar, about 1.0 and about 1.5 miUimolar, and about 1.0 and about 2.0 miUimolar).
  • the concentrations are in a range between about 10 micromolar to about 1000 micromolar, between about 100 micromolar to about 150 micromolar, or between about 200 micromolar to about 1200 micromolar.
  • An effective amount of a cationic polymer can be 0.005 mg/rnL, 0.01 mg/rnL, 0.025 mg/mL, 0.05 mg/mL, 1 mg/mL, etc.
  • modification of platelets with either a hydrogel-forming peptide/sialidase inhibitor/p-galactosidase inhibitor or a hydrogel-forming peptide/sialidase inhibitor/p-galactosidase inhibitor in combination with one or more glycan- modifying agents can be performed as follows.
  • the population of platelets is contacted with the selected hydrogel-forming peptide or hydrogel-forming peptide in combination with one or more sialidase inhibitors and/or ⁇ -galactosidase inhibitors, and/or in combination with one or more glycan-modifying agents.
  • Multiple hydrogel-forming peptides, sialidase inhibitors, ⁇ -galactosidase inhibitors, and/or glycan-modifying agents e.g., two, three, four or more
  • the hydrogel-forming peptides, the sialidase inhibitors, ⁇ -galactosidase inhibitors, and/or glycan-modifying agents are provided close enough in time to confer the desired effect.
  • 0.1-500 mU/rnL galactose transferase or sialyl transferase is added to the population of platelets.
  • Galactose transfer can be monitored functionally using lectins such as FITC-ECL or sWGA binding.
  • the goal of the glycan modification reaction is to reduce sWGA binding to resting room temperature sWGA binding- levels.
  • Galactose transfer can be quantified using 14 C-UDP-galactose.
  • UDP-galactose is mixed with 14 C-UDP-galactose to obtain appropriate galactose transfer.
  • Platelets are extensively washed, and the incorporated radioactivity measured using a ⁇ -counter. The measured cpm (counts per minute) permits calculation of the incorporated galactose.
  • Similar lectin-binding techniques are applicable to monitoring sialic acid transfer.
  • Similar assays can be used to assess the efficiency of cationic polymers.
  • the cationic polymers can be used alongside the other components such as hydrogel- forming peptides or they can be used in a subsequent step from hydrogel-forming peptides.
  • the isolated platelets can be treated with the platelet composition in a time period before significant reduction in quality and/or hydrolysis of sialic acid and/or ⁇ -galactose occurs.
  • the addition of the composition to the platelets can occur during the isolation process, shortly after the isolation process or within another time period.
  • the composition of the present invention can be added in a sterile manner. For example, after the blood is centrifuged by the apheresis machine and the platelets are separated from the rest of the blood components, the composition of the present invention can be added into the bag containing platelets. In another embodiment, the collection bag into which the platelets are deposited after centrifugation can already contain the composition of the present invention. In another embodiment, the composition of the present invention can be added to the bag into which the platelets are being collected simultaneously with the collection of the platelets.
  • the components can be mixed or agitated (e.g., bag turned upside down and right side up) to ensure that the platelets come into contact with inventive composition.
  • inventive composition e.g., bag turned upside down and right side up
  • contact of the inventive composition and the isolated platelets can occur during platelet donation or soon after platelet isolation (e.g., between 1 minute and about 120 minutes within platelet isolation).
  • composition of the present invention can be added to the isolated platelets "immediately" after donation, within a certain time period after donation, or
  • the composition of the present invention is contacted with the platelets in a range between about 1 minute and about 48 hours (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 min, 1 1 ⁇ 2 h, 2 h, 2 1 ⁇ 2 h, 3 h, 3 1 ⁇ 2 h, 4 h, 4 1 ⁇ 2 h, 5 h, 5 1 ⁇ 2 h, 6 h, 12 h, 18 h, 24 h, 30 h, 36 h, 42 h, or 48 h).
  • about 1 minute and about 48 hours e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
  • the inventive composition can be added after the platelets are isolated from the whole blood.
  • the addition of the inventive composition to the platelets can occur when the platelets from the donors are pooled.
  • the pooling bag that generally holds about 6 units of random donor platelets can include the inventive composition so that when the platelets are added to the pooling bag, the isolated platelets come into contact with the composition.
  • the composition can be sterilely connected to and introduced into the pooling bag during the pooling process or after the platelets are pooled.
  • the methods of the present invention include contacting the isolated platelets within 1 hour to about 8 hours (e.g., between 1 and about 3 hours). In an embodiment, contacting the inventive composition with the isolated platelets should occur before platelets are refrigerated.
  • a device for collecting and processing platelets has a container or bag for collecting platelets, wherein the container or bag includes the composition of the present invention.
  • the device includes a container or bag that contains the isolated platelets and at least one satellite container or bag, wherein the satellite container includes the composition of the present invention.
  • the bag containing the platelets and the bag containing the composition of the present invention can be in sterile communication with one another.
  • the platelets after being contacted with the inventive composition, can be stored at room temperature or be refrigerated. In certain aspects, platelets are refrigerated to enable storage for longer periods of time.
  • sialidase inhibitors inhibit bacterial proliferation and allow platelets to be stored at room temperature.
  • Hydrogel-forming peptides reduce the accessibility of surface glycans to endogenous and exogenous (e.g., bacterial) sialidases as well as ⁇ -galactosidases.
  • the platelet compositions of the present invention include an effective amount of a hydrogel-forming peptide with or without any combination of a sialidase inhibitor and a ⁇ -galactosidase inhibitor that is added to a population of platelets after the platelets have been obtained from a donor.
  • the novel platelet composition comprises an effective amount of a hydrogel-forming peptide, sialidase inhibitor, ⁇ -galactosidase inhibitor, hydrogel-forming peptide and sialidase inhibitor, hydrogel-forming peptide and ⁇ -galctosidase inhibitor, sialidase inhibitor and ⁇ -galctosidase inhibitor, or hydrogel-forming peptide and sialidase inhibitor and ⁇ -galactosidase inhibitor that is added to a population of platelets after the platelets have been obtained from a donor and the resulting platelet composition is stored for a period of time at room temperature without a substantial loss of in vivo hemostatic activity and inhibition of bacterial proliferation.
  • the novel platelet composition comprises an effective amount of a hydrogel-forming peptide and none, either, or both of a sialidase inhibitor and a ⁇ -galactosidase inhibitor that is added to a population of platelets after the platelets have been obtained from a donor; the resulting platelet composition is cooled to a temperature below room temperature; stored for a period of time at a temperature below room temperature and rewarmed back to room temperature without a substantial loss in vivo hemostatic activity.
  • the compositions also comprise cationic polymers, either as part of the solutions recited above or as a separate solution.
  • the cationic polymers can be part of a second platelet additive solution (PASII), optionally also having one or more of the following: sialidase inhibitors, ⁇ -galactosidase inhibitors, glycan-modifying agents, hydrogel-forming peptides and additional buffer/salt components.
  • temperature below ambient temperature interchangeably refer to any temperature between 28°C and -100°C.
  • the temperature is alternatively selected from the group of temperatures consisting of 27°C, 26°C, 25°C, 24°C, 23°C, 22°C, 21°C, 20°C, 19°C, 18°C, 17°C, 16°C, 15°C, 14°C, 13°C, 12°C, 11°C, 10°C, 9°C, 8°C, 7°C, 6°C, 5°C, 4°C, 3°C, 2°C, 1°C, 0°C, -1°C, -2°C, -3°C, -4°C, -5°C, -6°C, -7°C, -8°C, -9°C, and -10°C.
  • the platelet preparation is stored at a temperature of less than about 15°C, preferably less than 10°C, and more preferably less than 5°C. In some other embodiments, the platelet preparation is stored at room temperature. In other embodiments, the platelets are frozen, e.g., 0°C, -20°C, or -80°C, or cooler.
  • the term "period of time” refers to a duration of time during which platelets or platelet compositions are stored at any given temperature. The term “period of time” can range from seconds to minutes to hours to days to weeks.
  • the term "period of time” refers a number of hours including about 3 to about 120 hours, e.g., 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107,
  • treated platelets can be stored at room temperature for about 1 to about 14 days (e.g., about 7 days). In an aspect, the platelets can be refrigerated on any day or days during storage.
  • the treated platelets are stored at room temperature.
  • Treatment with one or more hydrogel- forming peptides with none, either, or both of one or more sialidase inhibitors and one or more ⁇ -galactosidase inhibitors, and optionally, one or more cationic polymers and/or glycan-modifying agents preserves/modifies the platelet population, i.e., preserves or improves the hemostatic function of the platelet population following transfusion into a mammal, and reduces the incidence of storage lesions in room temperature stored platelets, when compared to untreated platelet samples over a period of time following treatment.
  • Treated platelet samples stored at or below room temperature are thus suitable for autologous or heterologous transfusion after extended periods of storage time, in an embodiment, for at least about 2 days, at least about 3 days, at least about 4 days, at least about 5 days, at least about 6 days, at least about 7 days, at least about 8 days, at least about 9 days, at least about 10 days, at least about 11 days, at least about 12 days, at least about 13 days, at least about 14 days, at least about 21 days, or at least about 28 days.
  • any of the aspects or embodiments of the invention further comprise a step of warming the treated platelet preparation above room temperature, for example, by warming the platelets to 37°C. Warming can occur gradually or by stepwise temperature increases. It is preferable to warm either room-temperature-stored or cold- stored and treated platelet population by slow addition of heat, and with continuous gentle agitation such as is common with the rewarming of blood products.
  • a blood- warming device is disclosed at WO/2004/098675 and is suitable for rewarming a treated platelet population from cold storage conditions.
  • This invention provides a novel method to reduce pathogen-induced platelet degradation and inhibit pathogen growth/propagation by inhibiting pathogen sialidases and/or ⁇ -galactosidases.
  • Sialidase and/or ⁇ -galactosidase inhibitors exhibit anti-microbial properties that prevent pathogenic proliferation.
  • methods using hydrogel-forming peptides alone or in combination with the above-mentioned inhibitors, which cause an effective decrease in the accessibility of the surface glycans of platelets.
  • cationic polymers can be used.
  • pathogen refers to one or more microorganisms or the like that cause infection as described in (Dodd, R. Y. New Engl. J. Med. 327:419-421 (1992); Soland, E. M., et al. J. Am. Med. Assoc. 274: 1368-1373 (1995) and Schreiber, G. B., et al. New Engl. J. Med. 334: 1685-1690 (1996)).
  • Exemplary pathogens include, but are not limited to a virus, bacteria, parasite, protozoa, or fungus.
  • viruses include, but are not limited to Herpes simplex virus, HIV, hepatitis, hepatitis A, hepatitis B, hepatitis C, Respiratory syncycial virus, blue tongue virus, and bovine diarrhea virus.
  • Virus also includes Cytomegalovirus, Epstein-Barr virus, Herpes Simplex type I and II viruses, and other viruses that circulate freely in the blood, as well as cell- associated viruses.
  • Fungus includes, but is not limited to e.g., Aspergillus.
  • typical parasites include, but are not limited to, for example: Ameoba, Plasmodiunm, Leishmania, Mycosus profundus, Trypanosoma, Spirochete, and Arbovius .
  • Bacteria commonly associated with platelets and whose proliferation is inhibited by a hydrogel-forming peptide, cationic polymer, a sialidase inhibitor and/or a ⁇ -galactosidase inhibitor include, but are not limited to Aspergillus, Bacillus sp, Bacteroides eggerthii, Candida albicans, Citrobacter sp, Clostridium perfringens, Corynebacterium sp, Diphtheroid, Enterobacter aerogenes, Enterobacter amnigenus, Enterobacter cloacae, Enterococcus avium, Enterococcus faecalis, Escherichia coli, Fusobacterium spp., Granulicatella adiacens, Heliobacter pylori, Klebsiella sp, (K.
  • Serratia sp Staphylococcus sp (Coagulase-negative Staphylococcus, Staphylococcus epidermidis, Staphylococcus aureus), Streptococcus sp, (S. gallolyticus, S. bovis, S. pyogenes, S. viridans), Serratia marcescens, and Yersinia enter ocolitica.
  • pathogen-induced platelet degradation refers to any degree of platelet degradation, decrease in hemostatic activity, or increase in the clearance rate of platelets that is caused by one or more pathogens.
  • the term "detrimental effect” as used herein, can refer to a detrimental effect upon the viability of platelets (e.g., an increase in platelet degradation, decrease in hemostatic activity, or increase in the clearance rate of platelets) that is caused by one or more pathogens.
  • a detrimental effect upon the viability of platelets e.g., an increase in platelet degradation, decrease in hemostatic activity, or increase in the clearance rate of platelets.
  • “detrimental effect” as used herein, can also refer to the detrimental effect upon the patient (e.g., the consequences of the infection itself) that is caused by one or more pathogens such as sepsis.
  • bacterial contamination refers to contamination by any of the above-described bacterial pathogens or by non-pathogenic bacteria that are capable of producing bacteria-derived sialidase.
  • inhibiting bacterial proliferation refers to reducing and/or inhibiting the growth of bacteria in a platelet preparation.
  • bacteria-derived sialidase refers to sialidase that is produced by bacteria.
  • the inhibition of "bacteria-derived sialidase” as used herein can optionally inhibit platelet-derived sialidase and/or patient-derived sialidase in addition to the inhibition of bacteria- derived sialidase.
  • the invention in other aspects, provides a novel method to inhibition of bacterial proliferation in a platelet preparation by obtaining a population of platelets from a donor and contacting the platelets with an effective amount of the inventive compositions e.g., a hydrogel- forming peptide and/or a sialidase inhibitor and/or ⁇ -galactosidase inhibitor and/or a cationic polymer.
  • the methods of the present invention further include storing the treated platelet composition for a period of time at room temperature without a substantial loss of in vivo hemostatic activity.
  • the treated platelets or the resulting platelet compositions can be cooled to a temperature below room temperature; stored for a period of time at a temperature below room temperature, and rewarmed back to room temperature without a substantial loss of in vivo hemostatic activity.
  • Preferred embodiments of the inventive method to reduce pathogen growth in a platelet preparation include contacting platelets with an effective amount of a hydrogel- forming peptide, and/or a sialidase inhibitor and/or a ⁇ -galactosidase inhibitor and/or a cationic polymer (potentially during a separate step), as described herein, and optionally with an effective amount of at least one glycan-modifying agent, as described herein.
  • the anti-pro liferative inhibition of bacteria by the hydrogel-forming peptide and/or the sialidase inhibitor and/or the ⁇ -galactosidase inhibitor and/or the cationic polymer allows platelets to be stored for longer with a reduced risk of bacterial contamination, and for the time period described herein.
  • Bacterial contamination of platelets is a concern because it causes sepsis in patients receiving them. Bacterial contamination can be the result of non-sterile techniques in obtaining blood and/or platelets from the donor, or in poor handling of the platelets after donation. Despite good sterile techniques in obtaining donated blood or platelets, bacteria can still persist in the platelet preparation. For example, even though a technician uses an antibacterial agent to clean the skin at the site of donation, bacteria can be embedded within the layers of the skin, i.e., intradermally. So, upon penetration of the skin with a needle, bacterial contamination of the platelet donation can occur. As a result, bacterial testing at the point of care (e.g., at the time the recipient receives the platelets) is performed to reduce the risk of sepsis.
  • biofilm formation is the result of bacteria attaching to the interior surface of the bag and proliferating using the surface as a support. As the bacterial proliferation increases, the biofilm formation also increases.
  • contacting the platelet preparation with hydrogel-forming peptides, sialidase inhibitors, ⁇ -galactosidase inhibitors, cationic polymers, or a combination of the foregoing provides unexpected anti-pro liferative inhibition of bacteria and a reduction in biofilm formation on the interior surface of the platelet bag.
  • the platelet preparation is contacted with an effective amount of one or more hydrogel-forming peptides, one or more sialidase inhibitors, one or more ⁇ -galactosidase inhibitors, cationic polymers, or a combination thereof which inhibits endogenous platelet enzymes but also bacterial enzymes.
  • This treatment of platelets results in prolonged storage of platelets with reduced bacterial growth/proliferation, which provides platelets with an increased survival and hemostasis in vivo after transfusion into a recipient.
  • Encompassed in the method of the present invention is testing for bacterial proliferation at one or more time points to determine that bacterial proliferation is in fact inhibited before being transfused into the recipient.
  • Bacterial testing can occur at a single time point (e.g., at the point of care) and the results can be compared to a standard to determine if bacterial proliferation has occurred in the treated platelets to be transferred. Additionally, bacterial testing of the treated platelets can occur at more than one time point to assess if the particular sample has exhibited inhibition of bacterial proliferation.
  • An increase in bacterial proliferation or the presence of bacterial proliferation indicates that the treated platelets are contaminated and cannot be used for transfusion.
  • the absence of bacterial proliferation indicates that the treated platelets can be used for transfusion.
  • Using the hydrogel-forming peptide and/or the sialidase inhibitor and/or ⁇ - galactosidase inhibitor and/or the cationic polymer of the present invention results in treated platelets that are suitable for transfusion.
  • Bacteria can be tested by the presence of a polypeptide or protein that is common to bacteria and not found in platelets, by culture techniques, Gram staining, scanning techniques, the presence of nucleic acid that is conserved in bacteria, scans and the like.
  • a commonly used test in determining bacterial contamination of a platelet preparation is the Pan Genera Detection (PDG® test) (Verax Biomedical, Incorporated, Worcester Massachusetts).
  • the PGD® test can detect an array of bacteria in blood components. This broad detection is based on the existence of shared, or conserved, antigens that are common to the cell walls of the two broad classes of bacteria: lipoteichoic Acids on Gram-positive bacteria and lipopolysaccharides on Gram- negative bacteria.
  • the test targets these conserved Gram-positive and Gram-negative antigens to test biological samples for a broad range of bacterial contaminants by using binding agents to directly bind to these targets. Although the level or presence of the specific bacteria is not determined by this test, the test does determine the presence of a number of bacteria in the platelet preparation.
  • BacT/ ALERT® test bioMerieux, Inc., Durham, NC. Bacterial detection is based on the evolution of carbon dioxide by proliferating bacteria. A carbon-dioxide-sensitive liquid emulsion sensor at the bottom of the culture bottle changes color and is detected through alteration of light reflected on the sensor. BacT/ALERT® test detects the presence of a number of bacteria, fungi, and yeasts.
  • Another method for bacterial detection involves measuring the oxygen content in a platelet preparation sample.
  • An example is the Pall eBDS test (Pall Corporation, Port Washington, NY).
  • the approach to detection measures the oxygen content of air within the sample pouch as a surrogate marker for bacteria.
  • An oxygen analyzer is used to measure the percent of oxygen in the headspace gas of the pouch or bag having the platelets. If bacteria are present in the platelet sample collected, an increasing amount of oxygen is consumed through the metabolic activity and proliferation of the bacteria in the sample during incubation, resulting in a measurable decrease in oxygen content of the plasma as well as the air within the sample pouch.
  • Gram staining allows one to differentiate bacterial species into classes (Gram-negative or Gram-positive) in an effort to begin to identify the microorganism.
  • the test detects peptidoglycan, a glycan in the cell wall of the bacteria.
  • a sample from the treated platelet preparation can be obtained and cultured to determine if any bacteria are present.
  • the growth media is inoculated or plated with the sample and under controlled conditions suitable for bacterial growth. Bacteria can be grown and identified.
  • the methods of the present invention involve reducing bacterial proliferation and/or biofilm formation by contacting the platelet preparation with an effective amount of one or more hydrogel- forming peptides ,one or more sialidase inhibitors, one or more ⁇ -galactosidase inhibitors, one or more cationic polymers (potentially during a separate step) or a combination thereof.
  • the bacterial proliferation is reduced, as compared to a standard or to another assessment taken at a different time point.
  • the methods described herein reduce bacterial proliferation and/or biofilm formation by at least about 5% (e.g., by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100%).
  • the methods of the present invention completely inhibit bacterial proliferation and/or biofilm formation, as compared to that at the time of treatment of the platelet preparation with the hydrogel-forming peptide, the sialidase inhibitor, the ⁇ -galactosidase inhibitor, the cationic polymer or a combination of the foregoing.
  • the invention embraces a method for increasing the storage time of platelets.
  • platelets can be stored with reduced sialidase/p-galactosidase activity, inhibited bacterial proliferation, and without substantial loss of platelet function or hemostatic activity such as the loss of the ability to circulate or without an increase in the rate of platelet clearance.
  • the platelets are collected from blood by standard techniques known to those of ordinary skill in the art, as described herein.
  • the storage composition includes at least one hydrogel-forming peptide, and optionally any of at least one sialidase inhibitor, at least one ⁇ -galactosidase inhibitor, at least one glycan-modifying agent in an amount sufficient to reduce platelet clearance.
  • the storage composition can also include at least one cationic polymer.
  • the storage composition further comprises an enzyme that catalyzes the modification of a glycan moiety on the platelet.
  • the invention in certain aspects, provides a novel method of storing a platelet composition in which the steps include obtaining a population of platelets from a donor and treating the platelets with an effective amount of one or more hydrogel-forming peptides with none, either, or both of one or more sialidase inhibitors and one or more ⁇ -galactosidase inhibitors; and optionally one or more glycan modifying agents.
  • the methods can include treatment with one or more cationic polymers, either simultaneously with the other treatment steps or as a separate step (e.g., the platelets can first be mixed with a solution having hydrogel-forming peptides, incubated for 30 minutes, then mixed with a solution having cationic polymers, and then stored while retaining both types of compounds).
  • the novel method of storing a platelet composition involves obtaining a population of platelets from a donor; adding an effective amount of a hydrogel-forming peptide with none, either, or both of a sialidase inhibitor and a ⁇ -galactosidase inhibitor to the population of platelets and storing the resulting platelet composition for a period of time at room temperature without a substantial loss of in vivo hemostatic activity.
  • the novel method of storing a platelet composition encompasses obtaining a population of platelets from a donor; adding an effective amount of a hydrogel-forming peptide with none, either, or both of a sialidase inhibitor and a ⁇ -galactosidase inhibitor to the population of platelets; cooling the resulting platelet composition to a temperature below room temperature; storing the platelet composition for a period of time at a temperature below room temperature and rewarming the platelet composition back to room temperature without a substantial loss in vivo hemostatic activity.
  • cationic polymers can be added to the platelets either alongside other components such as hydrogel- forming peptides or during a separate step.
  • the platelet composition is rewarmed slowly. In certain embodiments, the platelet composition retains substantially normal hemostatic activity when transfused into a mammal after storage. In further embodiments, the platelet composition when transfused into a mammal after storage, has a circulation half- life of about 5% or greater than the circulation half-life of untreated platelets. In certain preferred embodiments, the platelet composition is suitable for transfusion into a human after storage.
  • the population of treated platelets can be stored at room temperature or chilled without the deleterious effects (cold-induced platelet activation) experienced upon chilling of untreated platelets.
  • the preservation and/or selective modification of glycan moieties reduce clearance, thus permitting longer-term storage than is presently possible.
  • one or more hydrogel-forming peptides, one or more cationic polymers, one or more sialidase inhibitors, one or more ⁇ - galactosidase inhibitors, or a combination thereof is added to the population of platelets that are kept between about room temperature (between about 20°C and 25°C) and 37°C.
  • chilling refers to lowering the temperature of the population of platelets to a temperature that is less than about 25°C.
  • the platelets are chilled to a temperature that is less than about 15°C.
  • the platelets are chilled to a temperature ranging from between about 0°C to about 4°C.
  • Chilling also encompasses freezing the platelet preparation, i.e., to temperatures less than 0°C, -20°C, -50°C, and -80°C or cooler. Processes for the cryopreservation of cells are well known in the art.
  • the population of platelets is stored at room temperature for at least 3 days.
  • the population of treated platelets is stored at room temperature for at least 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, and 28 days or longer.
  • a population of treated platelets can be stored chilled for at least 3 days.
  • a population of treated platelets is stored chilled e.g., for at least 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, or 28 days or longer.
  • the present invention provides a method of transfusing a patient with a treated platelet composition having one or more hydrogel-forming peptides, one or more cationic polymers, one or more sialidase inhibitors, one or more ⁇ -galactosidase inhibitors, or a combination thereof, wherein the platelet composition was prepared according to the methods described herein. Similarly, using these steps, the present invention provides a novel method for mediating hemostasis in a mammal.
  • the present invention relates to methods for increasing the circulation time of platelets, or reducing the clearance of platelets.
  • the circulation time of a population of platelets is defined as the time when one-half of the platelets in that population are no longer circulating in a mammal after transfusion into that mammal.
  • clearance means removal of the treated platelets from the blood circulation of a mammal (such as but not limited to by macrophage phagocytosis). More specifically, clearance of a population of platelets refers to the removal of a population of platelets from a unit volume of blood or serum per unit of time. Reducing the clearance of a population of platelets refers to preventing, delaying, or reducing the clearance of the population of platelets or the rate at which platelets clear.
  • Platelet transfusion Patients in need of platelet transfusion include those with e.g., anemia, thrombocytopenia, dysfunctional platelet disorders, active platelet-related bleeding disorders, or serious risk of bleeding (e.g., prophylactic use). Patients with certain medical conditions at times require platelet transfusion. Such conditions include, among others: leukemia, myelodysplasia, aplastic anemia, solid tumors, congenital or acquired platelet dysfunction, central nervous system trauma. Patients undergoing extracorporeal membrane oxygenation or cardiopulmonary bypass also receive platelet transfusions.
  • the method for increasing circulation time of an isolated population of platelets involves contacting an isolated population of platelets with at least one hydrogel-forming peptide, at least one cationic polymer, at least one sialidase inhibitor, at least one ⁇ -galactosidase inhibitor, or a combination thereof in an amount effective to reduce the clearance of the population of platelets.
  • the chosen ones among the aforementioned contacting steps e.g., adding one item to platelets, adding platelets to one item, or both adding one item to platelets and adding platelets to one item
  • a population of platelets refers to a sample having one or more platelets.
  • Reducing the clearance of a platelet encompasses reducing the clearance of platelets that results after storage of the platelets at or below room temperature. Reducing the clearance of a platelet can result from reducing storage lesions obtained at or below room temperature, or reducing "cold-induced platelet activation" that occurs upon the cold storage of platelets.
  • Cold-induced platelet activation is a term having a particular meaning to one of ordinary skill in the art. Cold- induced platelet activation can be manifested by changes in platelet morphology, some of which are similar to the changes that result following platelet activation. The structural changes indicative of room-temperature -induced or cold-induced platelet activation are most easily identified using techniques such as light or electron microscopy.
  • platelet activation results in actin bundle formation and a subsequent increase in the concentration of intracellular calcium.
  • Actin-bundle formation is detected using, for example, electron microscopy.
  • An increase in intracellular calcium concentration is determined, for example, by employing fluorescent intracellular calcium chelators.
  • Many of the above-described chelators for inhibiting actin filament severing are also useful for determining the concentration of intracellular calcium (Tsien, R., 1980, supra). Accordingly, various techniques are available to determine whether platelets have experienced room-temperature -induced or cold-induced activation.
  • hydrogel-forming peptide and/or cationic polymer and/or a sialidase inhibitor/p-galactosidase inhibitor prevents the hydrolysis of sialic acid/p-galactose residues from the termini of glycans and preserves the structures of glycan moieties on platelets, resulting in diminished clearance of treated platelets.
  • This effect can be measured, for example, using either an in vitro system employing differentiated THP-1 cells or mouse macrophages, isolated from the peritoneal cavity after thioglycolate injection stimulation. The rate of clearance of treated platelets compared to untreated platelets can be determined.
  • the treated platelets are fed to the macrophages and ingestion of the platelets by the macrophages is monitored. Reduced ingestion of treated platelets as compared to untreated platelets (1.2-fold or greater) indicates successful modification of the glycan moiety for the purposes described herein.
  • a hydrogel-forming peptide, a cationic polymer, a sialidase inhibitor, ⁇ - galactosidase inhibitor, or a combination thereof inhibits bacterial proliferation, which in turn, reduces platelet clearance and prevents sepsis. Assessment of bacterial proliferation is described herein.
  • the circulation time of the population of platelets is increased by at least about 10%, 20%, 25%, 30%, or 40%. In some embodiments, the circulation time of the population of platelets is increased by at least about 50% to about 100%. In yet other embodiments, the circulation time of the population of platelets is increased by about 150% or greater.
  • the platelets After being subjected to the hydrogel-forming peptide and/or the cationic polymer and/or the sialidase inhibitor and/or the ⁇ -galactosidase inhibitor, as described herein, the platelets are treated and are referred to herein as "platelet compositions" or "treated platelets.”
  • the present invention includes a novel platelet composition comprising one or more hydrogel-forming peptides, one or more cationic polymers, one or more sialidase inhibitors, one or more ⁇ -galactosidase inhibitors, or a combination thereof, as described herein.
  • the novel platelet composition further comprises an effective amount of at least one glycan-modifying agent.
  • the treated platelets have a plurality of intact glycan molecules on the surface of the platelet that would otherwise have been cleaved without sialidase inhibitor/p-galactosidase inhibitor treatment or without the hydrogel- forming peptide treatment or without the cationic polymer treatment.
  • the glycan molecules of the platelet composition of the present invention include those in which sialic acid/p-galactose cleavage is prevented and the glycan molecules remain intact.
  • the glycan-modifying agents e.g., CMP-sialic acid, or UDP-galactose, or both
  • the modified glycan moieties are GPIba molecules.
  • the invention also encompasses a platelet composition in a storage medium.
  • the storage medium can be a pharmaceutically acceptable carrier.
  • the terminal glycan molecules so modified are GPIba molecules.
  • the treated platelets include glycan structures with terminal GPIba molecules that following treatment have terminal galactose or sialic acid attached to the GPba molecules.
  • the invention provides a platelet composition comprising a plurality of treated platelets.
  • the platelet composition further comprises a storage medium.
  • the platelet composition further comprises a pharmaceutically acceptable carrier.
  • the population of platelets treated according to the inventive methods described herein demonstrates inhibited bacterial proliferation and substantially normal hemostatic activity, preferably after transfusion into a mammal. In some embodiments, the population of platelets treated according to the inventive methods described herein demonstrates reduced bacterial proliferation and improved hemostatic activity, relative to a similarly stored but untreated population of platelets.
  • the novel platelet composition provides a stable platelet preparation.
  • the stable platelet preparation of the invention is capable of being stored for at least 24-360 hours, and the platelet preparation is suitable for administration/transfusion to a human after storage without significant loss of hemostatic function or without a significant increase in platelet clearance in the human as compared to the same for untreated platelets.
  • the stable platelet preparation is capable of being cold-stored.
  • the platelets are capable of being stored at room temperature without substantial reduction in biological activity compared to the same for non-treated platelets.
  • compositions comprising a novel platelet composition, as described herein, and further comprising at least one pharmaceutically acceptable excipient.
  • a "pharmaceutically acceptable excipient,” as used herein, includes any and all solvents, diluents, or other liquid vehicle, dispersion or suspension aids, surface active agents, isotonic agents, thickening or emulsifying agents, preservatives, antioxidants, solid binders, lubricants, and the like, as suited to the particular dosage form desired.
  • Remington 's Pharmaceutical Sciences, Sixteenth Edition, E. W. Martin (Mack Publishing Co., Easton, PA, 1980) discloses various excipients used in formulating pharmaceutical compositions and known techniques for the preparation thereof.
  • the platelet composition is suitable for transfusion into a human patient afflicted with a bleeding or hemostatic disorder or a coagulopathy.
  • the platelet composition can be stored for at least 5 days with inhibited bacterial proliferation prior to administration to a human, and wherein the composition can be transfused into a human after storage without significant loss of hemostatic function or without a significant increase in platelet clearance in the human as compared to untreated platelets.
  • pharmaceutically acceptable means a non-toxic material that does not interfere with the effectiveness of the biological activity of the platelets and that is a non-toxic material that is compatible with a biological system such as a cell, cell culture, tissue, or organism.
  • Pharmaceutically acceptable carriers include diluents, fillers, salts, buffers, stabilizers, solubilizers, and other materials which are well known in the art, for example, a buffer that stabilizes the platelet preparation to a pH of 7.3 - 7.4, the physiological pH of blood, is a pharmaceutically acceptable composition suitable for use with the present invention.
  • the invention further embraces a method for making a pharmaceutical composition for administration to a mammal.
  • the novel pharmaceutical composition comprising platelets further comprises an effective amount of a hydro gel-forming peptide, a sialidase inhibitor, a ⁇ -galactosidase inhibitor, a cationic polymer, or a combination thereof that is added to a population of platelets after the platelets have been obtained from a donor and the resulting platelet composition is stored for a period of time at room temperature without a substantial loss in vivo hemostatic activity.
  • the novel pharmaceutical composition comprising platelets further comprises an effective amount of a hydro gel-forming peptide, a sialidase inhibitor, a ⁇ -galactosidase inhibitor, a cationic polymer, or a combination thereof that is added to a population of platelets after the platelets have been obtained from a donor and the resulting platelet composition is stored for a period of time at room temperature without a substantial loss in vivo hemostatic activity.
  • composition comprising platelets further comprises an effective amount of a hydrogel-forming peptide, a cationic polymer, a sialidase inhibitor, a ⁇ -galactosidase inhibitor, or a combination thereof that is added to a population of platelets after the platelets have been obtained from a donor; the resulting platelet composition is cooled to a temperature below room temperature; stored for a period of time at a temperature below room temperature and rewarmed back to room temperature without a substantial loss of in vivo hemostatic activity.
  • the method of preparing the novel pharmaceutical compositions comprising platelets comprises neutralizing, removing, or diluting the hydrogel-forming peptide/cationic polymer/sialidase inhibitor/p-galactosidase inhibitor and/or glycan-modifying agent(s) and/or the enzyme(s) that preserve and/or catalyze the modification of the glycan moiety, and placing the treated platelet preparation in a pharmaceutically acceptable carrier.
  • the platelets are stored at room temperature (about 22°C) prior to and during neutralization or dilution.
  • the platelets are chilled, stored, and then warmed to room temperature (about 22°C) prior to neutralization or dilution.
  • the platelets are contained in a pharmaceutically acceptable carrier prior to contact with the hydrogel-forming peptide/caionic polymer/the sialidase inhibitor/p-galactosidase inhibitor and/or glycan-modifying agent(s) and/or the enzyme(s) that preserve and/or catalyze the modification of the glycan moiety and it is not necessary to place the platelet preparation in a pharmaceutically acceptable carrier following neutralization or dilution.
  • neutralize refers to a process by which the hydrogel-forming peptides, cationic polymers, sialidase inhibitors, ⁇ -galactosidase inhibitors, and/or glycan-modifying agent(s) and/or the enzyme(s) that preserve and/or catalyze the modification of the glycan moiety are rendered substantially incapable of glycan modification of the glycan residues on the platelets, or their concentration in the platelet solution is lowered to levels that are not harmful to a mammal, for example, to less than 50 micromolar for the glycan-modifying agents.
  • the chilled platelets are neutralized by dilution, e.g., with a suspension of red blood cells.
  • the treated platelets can be infused into the recipient, which is equivalent to dilution into a red blood cell suspension. This method of neutralization advantageously maintains a closed system and minimizes damage to the platelets. In a preferred embodiment, no
  • An alternative method to reduce toxicity is by inserting a filter in the infusion line, the filter containing, e.g., activated charcoal or an immobilized antibody, to remove the hydrogel-forming peptides, cationic polymers, sialidase inhibitors, ⁇ -galactosidase inhibitors, and/or glycan-modifying agent(s) and/or the enzyme(s) that preserve and/or catalyze the modification of the glycan moiety.
  • the filter containing, e.g., activated charcoal or an immobilized antibody
  • Either or all of the hydrogel-forming peptides, cationic polymers, sialidase inhibitors, ⁇ - galactosidase inhibitors, and/or glycan-modifying agent(s) and/or the enzyme(s) that preserve and/or catalyze the modification of the glycan moiety also may be removed or substantially diluted by washing the treated platelets in accordance with standard clinical cell washing techniques.
  • the invention further provides a method for mediating hemostasis in a mammal.
  • the method includes administering the above-described treated platelets.
  • the transfusion of the treated platelets or pharmaceutical composition can be done in accordance with standard methods known in the art.
  • a human patient is transfused with red blood cells before, after, or during administration of the treated platelets.
  • the red blood cell transfusion can serve to dilute the administered, treated platelets, thereby neutralizing the hydrogel- forming peptides, he cationic polymers, the sialidase inhibitors, the ⁇ -galactosidase inhibitors, and/or glycan-modifying agent(s) and/or the enzyme(s) that preserve and/or catalyze the
  • the dosage regimen for mediating hemostasis using the treated platelets is selected in accordance with a variety of factors, including the type, age, weight, sex and medical condition of the subject, the severity of the disease, the route and frequency of administration. An ordinarily skilled physician or clinician can readily determine and prescribe the effective amount of treated platelets required to mediate hemostasis.
  • the dosage regimen can be determined, for example, by following the response to the treatment in terms clinical signs and laboratory tests. Examples of such clinical signs and laboratory tests are well known in the art and are described, for example in, HARRISON'S PRINCIPLES OF INTERNAL MEDICINE, 17th Ed., Fauci AS et al, eds., McGraw-Hill, New York, 2008.
  • the optimal concentrations and conditions for preventing room- temperature -induced activation or cold-induced activation of platelets by treating them with one or more hydrogel-forming peptides with none, either, or both of one or more sialidase inhibitors and one or more ⁇ -galactosidase inhibitors; and optionally a cationic polymers and/or a glycan- modifying agent, increasing amounts of these agents are contacted with the platelets prior to storing platelets at room temperature and/or exposing the platelets to a chilling temperature.
  • the optimal concentrations of the hydrogel-forming peptides, the cationic polymers, the sialidase inhibitors, the ⁇ -galactosidase inhibitors, and/or glycan-modifying agent(s) that prevent cleavage of the sialic acid, prevent cleavage of ⁇ -galactose, and/or catalyze the modification of the glycan moiety are the minimal effective concentrations that preserve intact platelet function as determined by in vitro tests ⁇ e.g. , observing morphological changes in response to glass, thrombin, cryopreservation
  • the invention in other aspects, provides a novel method of preparing a platelet composition involving obtaining a population of isolated platelets from a donor and treating the platelets with an effective amount of a hydrogel-forming peptide, a sialidase inhibitor, a ⁇ -galactosidase inhibitor, or a combination thereof within a time period described herein.
  • the platelets can be additionally treated with a cationic polymer.
  • the novel method of preparing a platelet composition comprises obtaining a population of platelets from a donor; adding an effective amount of a hydrogel-forming peptide, a cationic polymer, a sialidase inhibitor, a ⁇ - galactosidase inhibitor, or a combination thereof to the population of platelets and storing the resulting platelet composition for a period of time at room temperature without a substantial loss of in vivo hemostatic activity.
  • Some components, such as the cationic polymer can be added in a separate step from the other components.
  • the novel method of preparing a platelet composition includes obtaining a population of platelets from a donor; adding an effective amount of a hydrogel-forming peptide, a cationic polymer, a sialidase inhibitor, a ⁇ - galactosidase inhibitor, or a combination thereof to the population of platelets; cooling the resulting platelet composition to a temperature below room temperature; storing the platelet composition for a period of time at a temperature below room temperature and rewarming the platelet composition back to room temperature without a substantial loss in vivo hemostatic activity.
  • the platelet composition is rewarmed slowly.
  • the population of platelets retains substantially normal hemostatic activity when transfused into a mammal.
  • the population of platelets when transfused into a mammal has a circulation half-life of about 5% or greater (e.g., 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, or 150%) than the circulation half- life of untreated platelets.
  • the treated platelet population is suitable for transfusion into a human.
  • Preferred embodiments of the inventive methods of preparing a platelet composition as described herein encompass treating the population of platelets with an effective amount of a hydrogel-forming peptide, a cationic polymer, a sialidase inhibitor, a ⁇ -galactosidase inhibitor, or a combination thereof as described herein.
  • inventive methods of preparing a platelet composition involve treating a population of platelets an effective amount of a hydrogel- forming peptide, a cationic polymer, a sialidase inhibitor, a ⁇ -galactosidase inhibitor, or a combination thereof and further treating the population of platelets with an effective amount of at least one glycan-modifying agent, as described herein.
  • the invention provides for the combination of the methods of treating platelet described herein with one or more other methods of platelet preservation known in the art.
  • the methods of platelet modification provided in the present invention are useful in combination with the methods described in, e.g., but not limited to, the following US Patent Publication No.: 20090053198 Al, and US patents: 7,030,110; 7,029,654; 7,005,253; 6,900,231; 6,866,992; 6,730,783; 6,706,765; 6,706,021; 6,693,115; 6,638,931; 6,635,637; 6,566,379;
  • the present invention also provides sterile, single-use kits that are used for platelet collection, processing and storage, further including suitable packaging materials and instructions for using the kit contents. It is preferred that all reagents and supplies in the kit be sterile in accordance with standard medical practices, FDA regulations and AABB Standards involving the handling, storage and use of blood and blood products. Methods for sterilizing the kit contents are known in the art, for example, ethylene oxide gas, gamma irradiation, and the like.
  • the kit may include venipuncture supplies and/or blood collection supplies, for example a needle set, solution for sterilizing the skin of a platelet donor, and a blood collection bag or container.
  • the container is "closed", i.e., substantially sealed from the environment.
  • closed blood collection containers are well known in the art and provide a means of preventing microbial contamination of the platelet preparation contained therein.
  • kits containing supplies for blood collection and platelet apheresis may further include a quantity of one or more hydrogel-forming peptides with none, either, or both of one or more sialidase inhibitors and one or more ⁇ -galactosidase inhibitors, and with or without the glycan- modifying agent, sufficient to modify the volume of platelets collected and stored in the container.
  • kits can futher include a quantity of one or more cationic polymers, either together with other components or together with some of the other components or separate from other components.
  • the kit includes a blood collection system having a blood storage container wherein the hydrogel-forming peptide, the cationic polymer, the sialidase inhibitor agent, the ⁇ - galactosidase agent, or a combination is provided within the container in an amount sufficient to treat the volume of blood or platelets held by the container.
  • the quantity of the hydrogel-forming peptide, the cationic polymer, the sialidase inhibitor, the ⁇ -galactosidase inhibitor and the glycan- modifying agent will depend, in part, on which agent or agents are included, and in part on the volume of the container. It is preferred that the hydrogel-forming peptide, the cationic polymer, the sialidase inhibitor, the ⁇ -galactosidase inhibitor, and the glycan-modifying agent, in any of the combinations, be provided as a sterile non-pyogenic solution, but any of the agents or their combinations can also be supplied as a lyophilized powder. For example, a blood bag is provided having a capacity of 250 mL.
  • Contained in the blood bag is a quantity of hydrogel-forming peptide, cationic polymer, sialidase inhibitor, the ⁇ -galactosidase inhibitor, or a combination such that when 250 mL of blood is added, the final concentration of the inhibitor(s) and/or peptide(s) is
  • One or more of the aforementioned components can be stored in one compartment of a bag, or each in separate compartments (e.g., hydrogel is stored separately from the cationic polymer), or any combination of components can be stored in any combination of compartments within a bag.
  • the bag can have frangible connections between each compartment to allow one to break the connection and mix the components/platelets without compromising sterility.
  • compositions contain different concentrations of the hydrogel- forming peptide, the cationic polymer, the sialidase inhibitor, the ⁇ -galactosidase inhibitor, for example but not limited to quantities resulting in final concentrations of 10 micromolar to 10 miUimolar, and preferably 100 micromolar to 1.2 miUimolar of the hydrogel-forming peptide alone, the hydrogel-forming peptide together with the sialidase inhibitor and/or ⁇ -galactosidase inhibitor, or the hydrogel-forming peptide with the combination of the sialidase inhibitor, the ⁇ -galactosidase inhibitor, and the glycan-modifying agent.
  • the platelet functions can be assessed with various in vitro methods.
  • the recovery and survival of the treated platelets can be further evaluated, which are mostly performed with radioactive-labeled platelets in healthy volunteers in clinical trials.
  • Hemostatic activity refers to the ability of a population of platelets to mediate bleeding cessation (e.g., to form a clot).
  • Normal hemostatic activity refers to an amount of hemostatic activity seen in the treated platelets, that is functionally equivalent to or substantially similar to the hemostatic activity of untreated platelets in vivo, in a healthy (non-thrombocytopenic or non-thrombopathic mammal) or functionally equivalent to or substantially similar to the hemostatic activity of a freshly isolated population of platelets in vitro.
  • platelets After treatment, platelets can be assessed to determine if they maintained their function, e.g., their ability to activate and form a clot.
  • Various assays are available for determining platelet hemostatic activity (Bennett, J. S. and Shattil, S. J., 1990, "Platelet function," Hematology,
  • demonstration of "hemostasis” or “hemostatic activity” can also include a demonstration that platelets infused into a thrombocytopenic or thrombopathic (i.e., non- functional platelets) animal or human circulate and stop natural or experimentally-induced bleeding.
  • thrombocytopenic or thrombopathic i.e., non- functional platelets
  • laboratories use in vitro tests. These tests, which include assays of aggregation, secretion, platelet morphology and metabolic changes, measure platelet functional responses to activation. These in vitro tests reliably evaluate and predict in vivo hemostatic platelet function.
  • platelets treated with compositions of the present invention exhibit a level of platelet function similar to that of untreated but freshly obtained/isolated platelets.
  • a test that measures the platelets' ability to clot is an aggregation assay.
  • the platelet aggregation test uses an aggregometer to measure the cloudiness or turbidity of blood plasma.
  • Agonists to promote clotting are used in an aggregation assay.
  • Examples of agonists include adenosine diphosphate (ADP), epinephrine (adrenaline), thrombin, collagen, TXA2, and ristocetin. Since agonists are added to the sample in order to perform the test, the results are impacted if the donor of the sample is taking an anticoagulant. The addition of an agonist to a plasma sample causes the platelets to clump together, making the fluid more transparent. The aggregometer then measures the light transmission through the specimen to determine the extent of the clotting by the platelets in response to the agonist.
  • the platelets When an agonist is added, the platelets aggregate and absorb less light and so the transmission increases and this is detected by the photocell in the aggregometer.
  • the normal time for platelet aggregation varies somewhat depending on the laboratory, the temperature, the shape of the vial in which the test is performed and the patient's response to different agonists. Establishing normal clot times and amounts of agonists for an aggregation assay can be determined by one of skill in the art.
  • Exemplary amounts of agonist are as follows: ADP between 1 ⁇ to 10 ⁇ , collagen between 1 and 4 ⁇ g/mL, Ristocetin between 0.5 mg/mL and 1.5, 5 mg/mL, adrenaline between 5 and 10 ⁇ , arachadonic acid (precursor of TXA2) about 500 ⁇ g/mL, and thrombin between 50 nmol/L and 100 nmol/L.
  • ADP between 1 ⁇ to 10 ⁇
  • collagen between 1 and 4 ⁇ g/mL
  • Ristocetin between 0.5 mg/mL and 1.5
  • 5 mg/mL arachadonic acid (precursor of TXA2) about 500 ⁇ g/mL
  • arachadonic acid precursor of TXA2
  • thrombin between 50 nmol/L and 100 nmol/L.
  • Platelets that have about 65% or greater platelet aggregation in response to adenosine diphosphate (ADP), arachidonic acid, collagen, thrombin, TXA2, epinephrine, and/or ristocetin are considered platelets with normal clotting function.
  • ADP adenosine diphosphate
  • platelets treated with the hydrogel-forming peptides, cationic polymers, sialidase inhibitors, and/or ⁇ -galactosidase inhibitors of the present invention and exhibit about 65% or greater (e.g., about 65% to about 100%) platelet aggregation in an aggregation assay are considered to exhibit homeostatic activity.
  • thromboelastography is available, for example, from Haemonetics Corporation (Braintree, MA) under the trade name TEG.
  • thrombelastography a small sample of platelets (typically 0.36 mL) is placed into a cuvette (cup) which is rotated gently through 4° 45 ' (cycle time 6/min) to imitate sluggish venous flow and activate coagulation.
  • a sensor shaft is inserted into the sample a clot forms between the cup and the sensor.
  • the speed and strength of clot formation is measured in various ways and depends on the activity of the plasmatic coagulation system, platelet function, fibrinolysis and other factors that can be affected by illness, environment and medications.
  • four values that represent clot formation are determined by this test: the R value (or reaction time), the K value, the angle, and the MA (maximum amplitude).
  • the R value represents the time until the first evidence of a clot is detected.
  • the K value is the time from the end of R until the clot reaches 20 mm and this represents the speed of clot formation.
  • the angle is the tangent of the curve made as the K is reached and offers similar information to K.
  • the MA is a reflection of clot strength.
  • a mathematical formula determined by the manufacturer can be used to determine a Coagulation Index (CI), which takes into account the relative contribution of each of these 4 values into 1 equation.
  • CI Coagulation Index
  • Platelet function including its ability to activate before and/or after treatment with the composition and also after transfusion into an individual, can be assessed.
  • platelet activation markers include P-selectin, PAC-1, GPIIb, GPIIIa, GPIb and GPIIIa. Soluble and membrane bound markers can be assessed to determine the state of platelet activation and assess homeostasis of the treated platelet preparation.
  • Methods that measure soluble and membrane bound platelet markers include several suitable assays. Suitable assays encompass immunological methods, such as flow cytometry, radioimmunoassay, enzyme-linked immunosorbent assays (ELISA), chemiluminescence assays, and assessment with a volumetric capillary cytometry system.
  • the inventive methods use antibodies reactive with platelet markers or portions thereof.
  • the antibodies specifically bind with membrane bound and/or soluble platelet makers or a portion thereof. When the antibodies bind, they inhibit the function of the protein or marker to which they bind.
  • the antibodies can be polyclonal or monoclonal, and the term antibody is intended to encompass polyclonal and monoclonal antibodies, and functional fragments thereof.
  • polyclonal and monoclonal refer to the degree of homogeneity of an antibody preparation. They are not intended to be limited to particular methods of production.
  • immunological techniques detect platelet marker levels by means of an anti-platelet marker antibody (e.g., one or more antibodies).
  • Anti-platelet marker antibody includes monoclonal and/or polyclonal antibodies, and mixtures thereof. Labeling platelets with antibodies directed against surface membrane glycoproteins and then analyzing the binding by flow cytometry is a rapid and sensitive technique for assessing homeostasis. For example, GPIIb, GPIIIa and GPIb can be assessed using antibodies CD41, CD61, and CD42b, respectively. Elevated levels of membrane bound or soluble P-selection can indicate the extent of platelet activation and can be detected using monoclonal antibodies S12 or W40. Antibodies for detecting such markers can be purchased commercially or raised against an appropriate immunogen using methods known in the art.
  • Any method known now or developed later can be used for measuring membrane bound platelet markers.
  • One method for assessing membrane bound platelet marker levels, which the invention utilizes, is flow cytometry. Methods of flow cytometry for measuring platelet or membrane bound markers are well known in the art. (Shattil, Sanford J, et al. "Detection of
  • a sample comprising platelets can be contacted with an antibody having specificity for the marker under conditions suitable for formation of a complex between an antibody and marker expressed on platelets, and detecting or measuring (directly or indirectly) the formation of a complex.
  • the level of membrane bound markers can be assessed by flow cytometry by obtaining a first and second sample comprising platelets, contacting said first sample, serving as a control, with a platelet activation agonist, such as phorbol myristate acetate (PMA), ADP (adenosine
  • the method then involves contacting or staining the samples with a composition comprising an anti-platelet marker antibody, having a fluorescent label, preferably in an amount in excess of that required to bind the marker expressed on the platelets, under conditions suitable for the formation of labeled complexes between said antibody and activated platelets.
  • the amount of platelet activation in isolated platelets treated with the composition of the present invention and stored is similar to the amount of platelet activation from freshly obtained platelets from a donor.
  • a radioimmunoassay can also be employed.
  • endogenous platelet activation can be assessed by an immunobinding assay by obtaining a first and second sample comprising platelets, wherein each sample contains a preselected number of platelets; contacting said first sample with a platelet activation agonist, such as phorbol myristate acetate (PMA), ADP (adenosine diphosphate), thrombin, collagen, and/or TRAP (thrombin receptor activating peptide), under conditions suitable for activation of platelets in said first sample, preferably for a period of time effective to maximally activate said platelets, and preferably while maintaining the second sample under conditions suitable for maintaining the endogenous platelet activation level.
  • a platelet activation agonist such as phorbol myristate acetate (PMA), ADP (adenosine diphosphate), thrombin, collagen, and/or TRAP (thrombin receptor activating peptide
  • the samples are contacted with an antibody composition that is specific to the marker being assessed.
  • the antibody can have a radioactive label or a binding site for a second antibody that has the radioactive label.
  • the formation of the complex in the samples are detected, wherein the amount of complex detected in said second sample as compared to that detected in said first sample is indicative of the extent of platelet activation in said second sample. Assaying for Detection of Soluble Platelet Markers
  • soluble platelet marker is determined using an ELISA assay or a sandwich ELISA assay.
  • a sample e.g., blood
  • platelets are removed (partially or completely) from the sample, for example by preparation of serum or plasma (e.g., isolation of platelet poor plasma).
  • Samples are preferably processed to remove platelets within a time suitable to reduce artificial increases in soluble platelet marker, such as those due to secretion or proteolysis from platelets.
  • Samples can be further processed as appropriate (e.g., by dilution with assay buffer (e.g., ELISA diluents)). Additionally, the technician can add a reagent that stabilizes and prevents in vitro platelet activations. Examples of these stabilizing reagents are apyrase and prostaglandin El (PGEi).
  • assay buffer e.g., ELISA diluents
  • PGEi prostaglandin El
  • the method involves combining a suitable sample and a composition that includes an anti-platelet antibody as detector, such as biotinylated anti-platelet MAb and HRP-streptavidin, or HRP-conjugated anti-platelet Mab, and a solid support, such as a microtiter plate, having an anti-platelet marker capture antibody bound (directly or indirectly) thereto.
  • an anti-platelet antibody as detector such as biotinylated anti-platelet MAb and HRP-streptavidin, or HRP-conjugated anti-platelet Mab
  • a solid support such as a microtiter plate, having an anti-platelet marker capture antibody bound (directly or indirectly) thereto.
  • the detector antibody binds to a different epitope from that recognized by the capture antibody, under conditions suitable for the formation of a complex between said anti-platelet maker antibodies and soluble platelet marker.
  • the method involves determining the formation of complex in the samples.
  • the solid support such as a microtiter plate, dipstick, bead, or other suitable support, can be coated directly or indirectly with an anti-platelet maker antibody.
  • an anti-platelet marker antibody can coat a microtiter well, or a biotinylated anti-platelet marker Mab can be added to a streptavidin coated support.
  • a variety of immobilizing or coating methods as well as a number of solid supports can be used, and can be selected according to the desired format.
  • the sample (or standard) is combined with the solid support simultaneously with the detector antibody, and optionally with one or more reagents by which detection is monitored.
  • a known amount of soluble platelet maker standard can be prepared and processed as described above for a suitable sample. This standard assists in quantifying the amount of the maker detected by comparing the level of platelet marker in the sample relative to that in the standard. A physician, technician, or a qualified person can compare the amount of detected complex with a suitable control to determine if the levels are elevated.
  • Typical assays for platelet markers are sequential assays in which a plate is coated with first antibody, plasma is added, the plate is washed, second tagged antibody is added, the plate is washed, and bound second antibody is quantified.
  • binding kinetics revealed that in a simultaneous format, the off-rate of the second antibody was decreased and the assay was more sensitive.
  • a simultaneous format in which the solid support is coated with a capture antibody, and plasma and detector antibody are added simultaneously, can achieve enhanced sensitivity and is preferred.
  • a technician, physician, qualified person or apparatus can compare the results to a suitable control such as a standard, levels of one or more platelet markers in normal individuals, and baseline levels of the platelet markers in a sample from the same donor.
  • a suitable control such as a standard, levels of one or more platelet markers in normal individuals, and baseline levels of the platelet markers in a sample from the same donor.
  • the assay can be performed using a known amount of a platelet marker standard in lieu of a sample, and a standard curved established.
  • One can relatively compare known amounts of the platelet marker standard to the amount of complex formed or detected.
  • Storage lesions can be assessed to determine the health of a platelet and its ability to activate and form a clot.
  • Storage lesions include morphological and molecular changes to platelets upon storage at or below room temperature.
  • One of the first visible effects of platelet impairment is the irreversible loss of the discoid morphology towards a spherical shape, and the appearance of spiny projections on the surface due to calcium-dependent gelsolin activation and phosphoinositide- mediated actin polymerization.
  • Certain morphological changes induced in platelets can be readily observed under a microscope. A loss in shape is accelerated at low temperatures and particularly when platelets are exposed to temperatures lower than 20°C. In addition to increased modifications in shape, notable increases occur in intracellular calcium levels and in the degree of actin
  • platelets treated with the composition of the present invention maintain shape and function that is at least similar to or better than platelets not stored in the PAS of the present invention (e.g., stored in a known platelet storage solution such as INTERSOL ® solution (Fenwal, Inc., Lake Zurich, IL) and SSP+ TM solution
  • a known platelet storage solution such as INTERSOL ® solution (Fenwal, Inc., Lake Zurich, IL) and SSP+ TM solution
  • Platelets were stored at 4°C in the absence or presence of 1.2 mM nucleotide sugars and the total sialic acid was quantified.
  • the platelets were centrifuged, thoroughly washed, and resuspended in 140 mM NaCl, 3 mM KC1, 0.5 mM MgCl 2 , 5 mM NaHC0 3 , 10 mM glucose and 10 mM HEPES, pH 7.4. Aliquots of the resuspended platelets were lysed with RIP A buffer (Cell Signaling
  • the assay kit uses an improved Warren method in which sialic acid is oxidized to formylpyruvic acid, which reacts with thiobarbituric acid to form a pink colored product.
  • the absorbance at 549 nm is directly proportional to sialic acid concentration, which in the test sample can be calculated from a linear standard curve obtained from sialic acid standards per the manufacturer's instructions.
  • Fresh platelets contain ⁇ 10 ⁇ g (i.e., approximately 10 micro-grams) of sialic acid per mg of platelet protein.
  • Sialidase activity is a particular concern since it is presumably responsible for the loss of platelet sialic acid during storage. Therefore, in addition to the direct analysis of sialic acid content, quantification of the total platelet sialidase activity and surface sialidase activity during storage are critical to understand the mechanism of sialic acid loss. Furthermore, sialidase activity may hinder an attempted resialylation approach. A determination of the nature of the sialidases in fresh and stored platelets is important.
  • Neul is a lysosomal sialidase that is presumed to have a narrow substrate specificity.
  • the natural substrate for this enzyme is unknown and activity has only been reported on artificial substrates such as 4-MU-NeuAc and nitro-phenyl-NeuAc, but not on gangliosidases, fetuin, or sialyllactose.
  • Neu2 is a cytosolic enzyme with wide substrate specificity.
  • Neu3 is a plasma membrane-bound sialidase, originally described as ganglioside sialidase.
  • Neu3 preferentially hydrolyses gangliosides, although glycoproteins, 4-MU-NeuAc, sialyllactose, etc. are also hydro lysed. Lysosomal Neul and surface- bound Neu3 (antibodies are commercially available) were the focus of the current studies. As shown in Fig. 4, Neu3 can readily be visualized on the surface of fresh platelets and its expression is not affected by refrigeration. In contrast, Neul only demonstrated weak surface exposure on fresh platelets, consistent with its subcellular localization in an intracellular lysosomal granule. However, upon refrigeration for 48 h, its surface exposure is greatly increased. The data demonstrates that Neul is at least partially responsible for the platelet surface sialidase activity increase during refrigeration.
  • platelet storage under refrigeration promotes platelet surface sialic acid loss and increases platelet surface sialidase expression. Similar findings were also made for RT-stored platelets (not shown).
  • Sialidase activity increases during cold storage of mouse platelets and the sialidase inhibitor
  • DANA increases mouse platelet survival in vivo.
  • sialidase surface activity in isolated, intact, fresh mouse platelets and following cooling and rewarming using Amplex Red Neuraminidase (Sialidase) Assay Kit
  • sialidase activity ⁇ Clostridium perfringens (Component H) was measured over the same time period (inset). Neul surface expression is increased by 3.5 fold on stored platelets as determined by flow cytometry using anti-Neul specific antibodies (not shown). Fetuin as a competitive sialidase substrate during platelet storage:
  • Fetuin (1 mg/mL) was added to mouse platelet rich plasma prior to cold storage or to fresh platelets at room temperature and ⁇ -galactose exposure measured by flow cytometry using FITC conjugated RCA-1 -lectin, a lectin specific for exposed ⁇ -galactose.
  • Addition of fetuin greatly inhibits sialic acid hydrolysis during platelet storage, preventing RCA-1 binding.
  • Fetuin addition has no effect on RCA-1 binding to fresh platelets (Fig. 6).
  • the sialidase inhibitor DANA increases platelet life span in vivo:
  • the quantification of sialic acid was determined in freshly isolated platelets and long-term stored platelets using a Sialic Acid Quantification Kit (Sigma, St. Louis MI, USA).
  • the Sialic Acid Quantification Kit determines total N-acetylneuraminic acid (sialic acid) following the release from glycoconjugates using a2-3,6,8,9-neuraminidase to cleave all sialic acid linkages, including branched sialic acid. Results show that 2xl0 9 freshly isolated mouse platelets ( ⁇ 2.5 mg protein) contain ⁇ 3 ⁇ sialic acid. Following long-term storage, platelets lose >50% of their sialic acid content (not shown).
  • sialic acid normally covers ⁇ -galactose residues and permits platelet survival. These results show that normal platelet survival is regulated by hepatocyte ASGP receptor, independent of macrophages. Surface sialic acid is normally hydrolyzed by sialidases. These studies then addressed whether inhibition of sialidase activity in vivo has an effect on platelet survival.
  • Mouse platelets have prolonged survival after injecting mice with the specific sialidase inhibitor, sodium salt of 2,3-dehydro-2-deoxy-N-acetylneuraminic acid (DANA). Mice were injected with 100 mM DANA or PBS (phosphate buffered saline) as a control, after in vivo platelet biotinylation.
  • DANA 2,3-dehydro-2-deoxy-N-acetylneuraminic acid
  • Example 3 The role of sialylation/desialylation in defining the circulatory lifetimes of platelets Human platelets produce Neul and Neu3 and release Neul into plasma:
  • the studies herein address two novel mechanisms that contribute to increases in the clearance of platelets that occur following storage.
  • the first platelet clearance mechanism which is induced rapidly by refrigeration in the absence of plasma, is mediated when GlcNAc residues on the N-linked glycan of GPIba become exposed and are recognized by the lectin domain of the ⁇ 2 receptor on liver phagocytes.
  • the second clearance mechanism induced by long-term platelet storage in plasma in the cold, is of slow onset and occurs when GPIba is desialylated and recognized by the ASGP receptors on both liver hepatocytes and macrophages.
  • the glycan structures promoting platelet circulation or clearance are thus ideally suited for therapeutic manipulation by sialidases or GT activity ⁇ See Fig. 8).
  • Fig. 9 shows that human platelets contain both Neul and Neu3.
  • Fig. 10 shows that human platelets release Neul into plasma after 24 hours of storage in the cold, indicating that released Neul could mediate the removal of surface sialic acid from platelet GPIba.
  • sialidase activity associated with platelet surface increases with the time of cooling.
  • Human platelets express glycosyltransferases and release them into plasma upon activation:
  • Glycosyltransferases are expressed on platelets and packaged internally into a secretory compartment.
  • Platelets have a surface associated P4gal-T (P4Gal-Tl) that catalyzes the coupling of Gal in a ⁇ 1-4 linkage to exposed N-acetylglucosamine (GlcNAc) residues on the N- linked glycans of GPIba, improving short-term cooled mouse platelet circulation (Hoffmeister KM, Josefsson EC, Isaac NA, Clausen H, Hartwig JH, Stossel TP. Glycosylation restores survival of chilled blood platelets. Science. 2003 Sep 12;301(5639):1531-4).
  • Endogenous active platelet sialyltransferases incorporate sialic acid into GPIba:
  • Endogenous resialylation was studied by following the fate of i.v. injected fluorescent-CMP- sialic acid (FITC-SA) in mouse platelets. After the injection, platelets were isolated and analyzed for the incorporation of fluorescence by flow cytometry (Fig. 12) and by determining the extent to which the fluorescent-tag was incorporated into mouse (not shown) and human GPIba (Fig. 12) by SDS-PAGE and immunoblotting analysis. Similar results were obtained using C CMP-sialic acid, as shown in Fig. 12. FITC labeled CMP-SA (FITC-SA) or FITC alone (FITC) were injected into wild type mice.
  • FITC-SA fluorescent-CMP- sialic acid
  • mice were bled and FITC incorporation into platelets was determined by flow cytometry. Isolated human platelets were incubated with FITC (F), FITC-SA, or left untreated (-). Resting (Rest) and TRAP (TRAP) activated platelets were subjected to immunoblotting using anti-FITC (FITC), -GPIba, -allb or -von Willebrand factor (vWf) antibodies. Actin is shown as a loading control.
  • GPIba and GPV are observed.
  • other platelet receptors such as GPIX, GPIbp, GPVI, or ⁇ 3 remain unchanged following platelet storage independent of the storage temperature (Fig. 13).
  • TACE mediates proteolysis of GPIba and GPV during platelet refrigeration as shown by inhibition of TACE using the metalloprotease inhibitors GM6001 or platelets deficient for TACE (Fig. 14).
  • Fig. 14 the metalloprotease inhibitors GM6001 or platelets deficient for TACE
  • preservation of receptor loss during refrigerated platelet storage does not prevent clearance of refrigerated platelets (Fig. 14). Removal of sialic acid from TACE deficient platelets diminishes platelet circulatory lifetime (Fig. 15C).
  • Example 4 Surface sialic acid prevents loss of GPIba and GPV during platelet storage and rescues in vivo survival of mouse platelets
  • Platelet processing and storage are associated with platelet lesion ⁇ e.g., shape change, activation, release reaction, and apoptosis), which is partially due to loss of surface receptors.
  • ureafaciens a2-3,6,8-sialidase increased surface ⁇ -galactose exposure, but not ⁇ -GlcNAc, as detected by lectin binding assays in the flow cytometer (Fig. 16).
  • Fig. 17 presents progressive loss of surface GPIba and GPV in conjunction with decrease in sialic acid content (p ⁇ 0.05).
  • GPIba receptor expression was followed with multiple anti-GPIba antibodies to exclude the possibility that desialylation altered antibody binding to GPIba.
  • Fig. 19 confirms the flow cytometry data shown in Fig. 19 by using immunoblot analysis of total platelet lysates, platelet supematants, and corresponding platelet pellets with or with addition of neuraminidase and DANA.
  • Fig. 21 shows that fresh platelets treated with sialidase are cleared rapidly from the circulation in a process prevented by DANA addition to the storage buffer.
  • addition of DANA preserved receptors expression of room temperature stored mouse platelets (Fig. 22) and platelet survival (not shown).
  • Desialylation is required for TACE-mediated GPIba and GPV shedding:
  • Example 5 Bacterial contamination/proliferation in platelet concentrates leads to formation of excessive free sialic acid in the storage media
  • platelets are stored at room temperature. To reduce the risk of bacterial growth and iatrogenic infections after transfusion, platelet shelf life is limited to 5 days in the United States. Unlike red blood cells, platelets cannot be stored under refrigeration with less risk for bacterial growth and transfusion related infections. Refrigerated platelets are rapidly cleared from the recipient's circulation despite improved in vitro function. Refrigeration of platelets irreversibly clusters the platelet glycoprotein Iba (GPIba) complex, leading to rapid platelet clearance when infused through lectin-mediated pathways.
  • GPIba platelet glycoprotein Iba
  • platelets for transfusion at room temperature promotes bacterial growth in bacterially contaminated (unsterile) platelets.
  • Many bacteria are able to interact with platelets and induce platelet aggregation by direct interaction between a bacterial surface protein and a platelet receptor or an indirect interaction where plasma proteins bind to the bacterial surface and
  • proteases and glycosidases i.e sectreted enzymes
  • platelet products enzymes secreted by contaminating bacteria can truncate platelet glycans and/or accelerate platelet receptor shedding.
  • Platelets are especially susceptible to sialidase activity (sialic acid hydrolysis) since they are heavily decorated with glycans terminated by sialic acid.
  • sialidase-mediated loss of sialic acid residues will result in clearance of the desialylated platelets by the asialo-glycoprotein receptor (ASGR) of liver hepatocytes upon transfusion.
  • ASGR asialo-glycoprotein receptor
  • the presence of sialidase-producing bacteria in platelet product will be particularly detrimental to platelets.
  • asialoglycoconjugates may become substrates for the additional bacterial glycosidases. Subsequent release of underlying glycans will generate nutrients that will enhance bacterial proliferation and generate ligands for bacteria-platelet interactions.
  • sialidase-producing bacteria in platelet products desialylates sialylglycoproteins on platelets and in plasma and increases the free sialic acid concentration in the storage media.
  • the samples were centrifuged for 10 min at 1000 xg.
  • the resultant supernatants (platelet poor plasma, PPP) were further centrifuged for 10 min at 10,000 xg, 4°C.
  • the supernatants from the second spin (platelet- free plasma, PFP) were analyzed for free sialic acid using QUANTICHROM ® Sialic Acid Assay Kit (BioAssay Systems, Hayward, CA) according to the manufacturer's instructions.
  • Sialidase-producing bacteria are potentially present in all platelet products.
  • the bacterial sialidase can desialylate platelets, compromising their biological functions.
  • Example 6 Bacterial proliferation in platelet product can be inhibited by sialidase inhibitor
  • Sialidases play important role in pathogenicity and nutrition of sialidase-producing bacteria.
  • Sialic acid occupies the terminal position within glycan molecules on the surfaces of many vertebrate cells, where it functions in diverse cellular processes such as intercellular adhesion and cell signaling.
  • Pathogenic bacteria have evolved to use this molecule beneficially in at least two different ways: 1) they can coat themselves in sialic acid, providing resistance to components of the host's innate immune response, 2) or they can use it as a nutrient.
  • Sialic acid itself is either synthesized de novo by these bacteria or scavenged directly from the host.
  • Our discovery of the presence of sialidase-producing bacteria as contaminants in platelet product suggests a novel approach of inhibiting bacterial growth in platelet products by inhibiting sialidase activity with sialidase inhibitors.
  • Sialidase inhibitors are not new to the pharmaceutical industry.
  • the influenza virus medicines Tamiflu and Relenza inhibit the influenza virus sialidase, which is required for spreading of the virus from infected cells.
  • they have not been used in platelet products.
  • platelets are suspended in 100% plasma.
  • plasma (rather whole blood) is the natural medium of platelets in vivo, it might have deleterious effects on platelets during storage, because plasma enzymes such as proteases can damage platelet membranes.
  • a storage solution that can maintain platelet function as well or better than plasma is desirable, in part to make plasma available for other purposes, but especially to mitigate transfusion-related adverse reactions, such as TPvALI. Therefore, much attention has been devoted to platelet additive solutions with satisfactory platelet preservation capacity with low residual plasma.
  • PASs Platelet additive solutions
  • prophenoloxidase prophenoloxidase
  • DOPA 3,4-dihydrophenylalanine
  • the pellet containing both platelets and bacteria recovered from 1-mL aliquots sampled at different time points, was re-suspended in 100 ⁇ , of 0.1 M NaOH, and heated for 10 min at 70°C. After brief cooling, the solution was neutralized with 135 iL of 80 mM MES. The reaction mixtures were clarified by centrifugation (5 min at 15,800 xg). Aliquots of 10 of the supernatant were mixed with equal volumes of SLP reagent, reconstituted from the components in the SLP kit following the manufacturer's instructions. The samples were left on the bench, and color development was monitored. The time of color detection (TOCD) was recorded.
  • TOCD time of color detection
  • Fig. 27 Selected photographs taken during the analysis of Day 9 samples are shown in Fig.27, panels A-C. Light, but visible, color development was observed after 15 min for RT-stored sample without DANA, suggesting the highest bacterial concentration in this sample.
  • TOCD was extended to ⁇ 34 min in the presence of DANA (#3, Fig. 27, panel B). Not surprisingly, bacterial growth is greatly inhibited at low storage temperatures, TOCD in 4°C-stored samples (Fig.27, panel C) ( ⁇ 45 min) was increased compared to TOCD in RT-stored sample in the absence or presence of DANA. Its TOCD at 4°C is further extended in the presence of DANA ( ⁇ 50 min, Fig. 27 panel C). Quantitative data is shown in Fig. 27, panel D. Conclusion:
  • Sialidase inhibitor DANA can effectively inhibit the bacterial growth during platelet storage. Although the nature of the bacteria is unknown, they are likely sialidase-producing bacteria. In addition, it was observed that the contaminating bacteria are not completely dormant at 4°C.
  • Example 7 DANA inhibits bacterial proliferation in stored mouse platelets and improves the survival and recovery of mouse platelets in vivo
  • Mouse platelets have a life-span of approximately 4-5 days, considerably shorter than human platelets (8 - 10 days). They are also much less stable than human platelets when stored at room temperature or 4°C.
  • the mechanism of the rapid deterioration in vitro of mouse platelet is not well understood, however it is possible that mouse platelet storage is affected by bacterial contamination due to endogenous bacteria and a lack of aseptic platelet procurement protocol, in contrast to the collection of human platelets. To date, it remains unclear if potential bacterial contamination contributes to the rapid deterioration of mouse platelets.
  • Mouse blood was obtained from anesthetized mice using 3.75 mg/g of Avertin (Fluka Chemie, Steinheim, Germany) by retro-orbital eye bleeding into 0.1 volume of Aster- Jandl anticoagulant and centrifuged at 300 x g for 8 min at RT to obtain platelet rich plasma (PRP).
  • Avertin Fluka Chemie, Steinheim, Germany
  • Platelets were separated from plasma by centrifugation at 1200 x g for 5 min and washed twice in 140 mM NaCl, 5 mM KC1, 12 mM trisodium citrate, 10 mM glucose, and 12.5 mM sucrose, 1 ⁇ g/mL PGEl, pH 6.0 (platelet wash buffer) by centrifugation.
  • Washed platelets were re-suspended at a concentration of 1 x 10 9 /mL in 140 mM NaCl, 3 mM KC1, 0.5 mM MgCl 2 , 5 mM NaHC0 3 , 10 mM glucose and 10 mM HEPES, pH 7.4 (platelet resuspension buffer), labeled with 5 ⁇ 5- chloromethylfluorescein diacetate (CMFDA) for 15 min at 37°C. Unincorporated dye was removed by centrifugation and platelets suspended in plasma. DANA, sialyllactose, and glucose (as a nutrient) were added to final concentrations of 0.5, 0.5 and 8 mM, respectively, from their corresponding PBS stock solutions.
  • CMFDA 5- chloromethylfluorescein diacetate
  • the platelet suspensions were stored at 4°C or RT for 48 h. After 48 h, the stored platelets were transfused by retro-orbital injection of 3xl0 8 platelets in 200 ⁇ xL. Following transfusion, blood was collected by retro-orbital eye bleeding at time points of 5 min, 2 and 24 h. The percentage of CMFDA positive platelets in
  • PRP was determined by flow cytometry.
  • Sialidase inhibitor DANA is capable of effectively preserving mouse platelets from deterioration during storage and greatly improving the recovery and survival of transfused platelets.
  • Example 8 Preservation of mouse platelets in the presence of different concentrations of DANA
  • DANA is a potent, broad-spectrum sialidase inhibitor against viral, bacterial and mammalian sialidases with Ki in the low ⁇ range. It is used routinely at 1 mM in all our studies. It is expected that its concentration can be dramatically lowered while maintaining its efficacy against the bacteria-caused deterioration of stored mouse platelets.
  • Mouse platelets were isolated as described in Example 3, re-suspended in platelet resuspension buffer and split to four aliquots. Glucose was added 8 mM to all samples, and DANA was added to final concentrations of 0, 0.1, 1.0, and 10 mM, respectively, both from 100 mM stock solutions in PBS. The samples were incubated for 30 min at 37°C, centrifuged and supernatants removed. The platelets re-suspended in plasma. DANA and glucose were restored to their initial concentrations. The platelet suspensions were stored at RT. After 48 h, platelets under each storage condition were counted by flow cytometry. Results:
  • Sialidase inhibitor DANA is capable of effectively preserving mouse platelets from deterioration, greatly improving the recovery and survival of the transfused platelets.
  • Example 9 Inhibition of the proliferation and biofilm formation of Serratia marcescens by sialidase inhibitor DANA
  • PCs Platelet concentrates
  • Serratia marcescens is a Gram-negative bacterium that has been implicated in adverse transfusion reactions associated with contaminated platelet concentrates. It produces a range of extremely virulent products including proteases, nucleases, lipases, chitinases and haemolysin; however, the presence of a secreatable sialidase has not yet been described. Based on the virulent characteristics of the secreted products by Serratia marcescens, the presence of sialidases is highly plausible. Therefore, this strain was chosen to test our sialidase- inhibition strategy to inhibit bacterial growth.
  • the Serratia marcescens strain (ATCC # 43862) has previously been used in studies involving bacterial detection and growth in blood products.
  • Serratia marcescens strain (ATCC # 43862) was purchased from American Type Culture
  • the cryostock of Serratia marcescens was inoculated into 3 mL of brain-heart infusion broth with a cotton swab and incubated at 37°C with agitation at 250 rpm for 6 h.
  • the cell density was determined at 600 nm on a dual wavelength spectrometer and diluted to 0.5 McFarland Standard (1.5 x 10 8 cells/mL) with sterile PBS.
  • Ten ⁇ ⁇ of the diluted culture was inoculated into 140 ⁇ _, of 30% plasma in PAS, 30% PC by volume in PAS or 100% plasma, supplemented with or without 1 mM DANA, in the wells of 96-well PVC plates (Corning
  • Sialidase inhibitor DANA is capable of inhibiting the proliferation and biofilm formation of
  • S. marcescens when analyzed with 96-well PVC plate.
  • the data also show that S. marcescens contains a previously unreported machinery to obtain and/or utilize sialic acid to proliferate and/or form biofilms.
  • Example 10 Variations in platelet surface glycans among healthy volunteers
  • Platelets have the shortest shelf life of all major blood components and are the most difficult to store. These limitations complicate platelet transfusion practices. Dr. Slichter and colleagues (Puget Sound Blood Center, Seattle, WA) have identified significant differences in recovery and survival of transfused fresh radiolabeled autologous platelets among healthy subjects. The cause of the inter-individual differences in platelet recovery and survival remains unclear.
  • Venous blood was obtained from volunteers by venipuncture into 0.1 volume of Aster Jandl citrate-based anticoagulant. Approval for blood drawing was obtained from the Institutional Review Board of Brigham and Women's Hospital, and informed consent was approved according to the Declaration of Helsinki.
  • Platelet-rich plasma (PRP) was prepared by centrifugation at 125 xg for 20 min and platelets were separated from the plasma proteins by gel-filtration through a small
  • Sepharose 2B column Isolated platelets were incubated for 20 min at room temperature with 10 ⁇ g/mL of the ⁇ -galactose specific FITC-conjugated E. cristagalli lectin (ECL). The samples were diluted with 200 of PBS and immediately analyzed by flow cytometry on a FACSCalibur flow cytometer (Beckton Dickenson). The mean fluorescence intensity was determined in gated platelet population.
  • Example 11 General procedure of preparing platelet additive solution containing a sialidase inhibitor
  • the PAS of the present invention can be made as follows.
  • the total volume of the bag is 500 mL.
  • Electrolytes such as Na, CI, K, Ca, and Mg.
  • An energy source such as glucose or citrate to sustain aerobic metabolism.
  • a buffer such as phosphate.
  • Table 2 provides the concentrations and amount (grams) of components including energy sources, buffers and electrolytes required to prepare 1000 mL of platelet additive solution. Water is added in an amount of 1000 mL and the solution is buffered to maintain a pH of pH 7.2.
  • Sialidase inhibitor such as DANA can be added from sterile 0.1-1000 mM stock solution in water to the desired concentrations. Table 2
  • Example 12 Preservation of mouse platelets in PAS containing a sialidase inhibitor
  • Mouse platelets have a life span of approximately 4-5 days, considerably shorter than human platelets (8-10 days). They are also much less stable than human platelets when stored at room temperature or 4°C. However, these shortcomings of mouse platelets can be exploited to assess the efficiency of platelet additive solutions for the preservation of platelets.
  • Mouse blood was obtained from anesthetized mice using 3.75 mg/g of Avertin (Fluka Chemie, Steinheim, Germany) by retro-orbital eye bleeding into 0.1 volume of Aster- Jandl anticoagulant and centrifuged at 200 xg for 8 min at RT.
  • PRP platelet rich plasma
  • Four 150 aliquots of PRP were transferred to 4 x 1.5 mL Eppendorf tubes, and centrifuged at 1000 x g for 5 min. About 70% of the supernatant (105 ⁇ ) was removed from each tube, and replaced with equal volume of INTERSOL ® solution.
  • DANA and/or glucose (as a nutrient) were added to final concentrations of 1.0 and 10 mM, respectively, from 100 mM stock solutions in PBS.
  • the volumes in tubes lacking one or both additives were evened out with PBS.
  • the platelet suspensions were stored at RT for 48 h on a shaker and analyzed by flow cytometry.
  • mouse platelets deteriorated rapidly in INTERSOL ® solution, when stored at RT (Fig. 33, panel Aa). Only 57% platelets were gated (Fig. 33, panel Ba). Remarkably, over 80% of the original platelet events were counted within the platelet gate when stored with 1 mM sialidase inhibitor DANA (Fig. 33, panels Ab and Bb). Addition of 10 mM glucose resulted in even higher platelet counts recovery after storage (Fig. 33, panels Ac and Be). A combination of both DANA and glucose preserved all platelets (93% gated, Fig. 33, panels Ad and Bd).
  • DANA alone or a combination with glucose results in a more resting platelet population as judged by their forward and side scatter characteristics (the population is "less elongated", i.e., formed less platelet aggregates) than glucose alone (Fig. 33, panels Ab and Ad, compare with Fig. 33, panel Ac).
  • This data suggests that DANA is more effective than glucose in preserving platelets in a resting state and in preserving platelet numbers following platelet storage.
  • Example 13 Improved in vitro quality of human platelets stored in plasma in the presence of sialidase inhibitor DANA
  • the state of a "healthy" platelet is partially defined by its shape and size. Platelet shape change and aggregation are hallmarks of platelet activation. Once activated, platelets change shape and secrete their granular contents. Storage of platelets is accompanied by platelet activation, i.e. platelet shape change and granule release. Human platelets also increase surface sialidase expression and lose surface sialic acid during storage. Presumably, sialidases are stored in granules and are released to the platelet surface during storage. The results from Example 12 suggest that mouse platelets may also lose sialic acid during storage and this process can be effectively inhibited by the presence of sialidase inhibitor DANA in the storage, greatly improving the post-transfusion recovery and survival of platelets. The data further indicate that the quality of stored human platelets can be improved by including a sialidase inhibitor in the storage media.
  • Resting platelets have a discoid shape and produce different side-scatter (SSC) signals in the flow cytometer, depending on their relative orientation to the laser beam.
  • SSC side-scatter
  • a resting platelet population has a wide ("round") distribution in the SSC/FSC signal.
  • platelets Upon stimulation, platelets form pseudopods and become spherical (shape change) thereby producing a characteristic SSC signal irrespective of their relative orientation to the laser beam. Therefore, an activated platelet population appears more "condensed" on a FCS/SSC plot.
  • DANA affects human platelet activation (i.e. shape change and granule release) during storage in plasma.
  • Venous blood was obtained from volunteers by venipuncture into 0.1 volume of Aster Jandl citrate-based anticoagulant. Approval for blood drawing was obtained from the Institutional Review Board of Brigham and Women's Hospital, and informed consent was approved according to the Declaration of Helsinki.
  • Platelet-rich plasma (PRP) was prepared by centrifugation at 125 xg for 20 min and platelets were separated from PRP after adding PGE1 (1 ⁇ g/mL) by centrifugation for 5 min at 850 xg. The supernatant (platelet-poor plasma, PPP) was saved. The platelet pellet was resuspended in PPP, 1/2 volumes of original PRP, and divided into aliquots.
  • DANA was added to 1.0 mM from 100 mM stock in PBS to half of the aliquots, only PBS was added to the controls.
  • the samples were stored in the wells of a 96-well microtiter plate covered with a gas-permeable film with agitation on a shaker at room temperature. Platelet size and density were measured by forward (FSC) and side scatter (SSC) on a FACSCalibur flow cytometer (BD). Platelets were gated by their forward and side scatter characteristics.
  • Example 14 Improved in vitro quality of human platelets stored in PASs containing sialidase inhibitor DANA
  • Example 12 demonstrated that sialidase inhibitor DANA can effectively preserve the quality of mouse platelets stored 30% plasma in platelet additive solution referred to as INTERSOL ® solution.
  • Data described in Example 13 clearly showed that DANA is also effective for preserving the quality of human platelets in 100% plasma.
  • the studies were extended to human platelets stored in plasma/PAS in a ratio of 30:70, in the absence or presence of DANA.
  • DANA can effectively preserve the quality of human platelets in 30% plasma in a platelet additive solution, i.e., reduce platelet activation and microparticle formation, showing that a sialidase inhibitor such as DANA can be used as an important component in PAS formulations for platelet storage.
  • Example 15 Variability of platelet surface sialidase activities among healthy individuals and up-regulation of these activities during platelet storage at RT
  • Platelets have the shortest shelf life of all major blood components and are the most difficult to store. These limitations complicate platelet transfusion practices. The loss of sialic acid from the surfaces of cold-stored and transfused platelets promotes clearance of platelets by hepatic
  • Asialoglycoprotein receptors (Ashwell-Morell receptors). The loss of platelet surface sialic acid correlates with increases in surface sialidase activity during platelet storage under refrigeration.
  • Platelets were isolated from platelet concentrates (PC) stored under blood banking conditions by centrifugation, washed, re-suspended at a concentration of 1-10 x 10 9 /mL in 140 mM NaCl, 3 mM KC1, 0.5 mM MgCl 2 , 5 mM NaHC0 3 , 10 mM glucose, and 10 mM Hepes, pH 7.4 (buffer A). Platelet sialidase activity was determined by incubation of platelets ( ⁇ 10 8 platelets) at 37 °C with 125 ⁇ 2'-(4-methylumbelliferyl)-a-D-N-acetylneuraminic acid (4-MU-NANA) in 100 mM
  • Example 16 Variability of platelet surface ⁇ -galactosidase activities among healthy
  • Mammalian neuraminidases have been classified as lysosomal (Neul), cytosolic (Neu2), plasma membrane (Neu3) and mitochondria/lysosomal (Neu4) based on their subcellular distributions, pH optima, kinetic properties, responses to ions and detergents and substrate specificities.
  • Neul lysosomal
  • cytosolic cytosolic
  • Neuro3 plasma membrane
  • Neu4 mitochondria/lysosomal
  • Neul initiates the intralysosomal hydrolysis of sialo-oligosaccharides, -glycolipids, and - glycoproteins by removing their terminal sialic acid residues.
  • Neul forms a complex with at least two other proteins, ⁇ -galactosidase and the protective
  • PPCA protein/cathepsin A
  • Platelets were isolated from platelet concentrates stored under blood banking conditions by centrifugation, washed, re-suspended in platelet wash Buffer A and counted by flow cytometry.
  • Platelet ⁇ -galactosidase activity was determined by incubation of washed platelets (-5-10 8 platelets) or PC at 37 °C with 2.5 mM Gaip-pNP in 100 mM NaOAc (pH 5.0), 80 mM NaCl. Reaction mixtures were sampled at various time points and the reactions were quenched with 1.5 volumes of 200 mM glycine/NaOH (pH 10.4), clarified by centrifugation and read on a spectrophotometer plate reader at 405 nm.
  • ⁇ -Galactosidase activity was readily detected with washed platelets or directly with platelet concentrates. Enzyme activity varies among donors, but is up-regulated during platelet storage. It is noted that Donor B, exhibiting higher sialidase activity, also exhibited higher ⁇ -galactosidase activity. See Fig. 43.
  • Example 17 Isolated platelets from healthy volunteers differ in terminal ⁇ -galactose content, and this correlates with platelet ingestion by HepG2 cells in vitro
  • Platelet surface sialidase catalyzes the release of sialic acids from the platelet surface and exposes ⁇ -galactose residues.
  • the presence of ⁇ -galactosidase on the platelet surface suggests that the platelet surface ⁇ -galactose exposure may vary among individuals and over the course of platelet storage.
  • HepG2 ingests sialyltransferase-deficient mouse platelets (ST3Gal-IV "/_ platelets) and sialic acid-deficient, refrigerated human platelets in vitro.
  • This cell line expresses the Asgr (Ashwell Morell Receptor), which specifically recognizes platelets in vitro and in vivo. See Fig. 37. Whether platelets with high or low terminal ⁇ -galactose initiate endocytosis by hepatocytes will be determined in HepG2 cultures.
  • Platelets are isolated by centrifugation, washed with PBS and resuspended in PBS, 1/5 of original plasma volume. Platelets are counted by flow cytometry and then diluted appropriately. Lectins are diluted appropriately in PBS. Five ⁇ of diluted platelets is added to the 100 ⁇ , of lectin and incubated for 15 min. After incubation, 300 ⁇ PBS is added to lectin-platelet solution and analyzed by a flow cytometer.
  • CM-Orange fiuorescently labeled fresh platelets
  • ⁇ -galactose on surface glycoproteins (e.g., glycans lacking sialic acid) on freshly-isolated platelets varies considerably among healthy subjects as measured by RCA-I lectin binding assay (Fig.38). Platelets from subject 1 have the highest surface ⁇ -galactose exposure, while those from subject 6 have the lowest surface ⁇ -galactose exposure. These findings were confirmed by HepG2 assay. See Figs. 39A and 39B.
  • Example 18 Terminal ⁇ -galactose content decreases on platelet surfaces over the course of platelet storage and correlates with ingestion by HepG2 cells
  • Example 17 we extended our studies as described in Example 17 to platelets isolated from platelet concentrates stored under standard blood banking conditions.
  • Human platelets have variable (among donors) surface sialidase and ⁇ -galactosidase activities, both of which are up-regulated during platelet storage at RT. In addition, human platelets have variable surface ⁇ -galactose exposure/sialic acid loss among individual donors. During storage at RT, platelet surface ⁇ -galactose exposure appears to peak at day 2, then decrease during further storage.
  • Example 19 Fresh platelets bear terminal ⁇ -galactose, which is readily cleaved by ⁇ - galactosidase exposing ⁇ -GlcNAc thereby leading to ingestion by THP-1 cells
  • Fresh platelets treated with ⁇ -galactosidase are readily ingested (4-fold increase) by the macrophage-like cell line THP-1 when compared to control platelets. These results show that fresh platelets have terminal ⁇ -galactose, which can be readily accessed and cleaved by ⁇ -galactosidase. This maneuver exposes underlying ⁇ -GlcNAc residues. Exposure of ⁇ -GlcNAc presumably promotes ingestion of platelets via the ⁇ 2 macrophage receptor. See Fig. 44.
  • Fresh isolated platelets have exposed ⁇ -galactose showing that platelets contain desialylated glycans.
  • Removal of ⁇ -galactose using ⁇ -galactosidase exposes terminal N-acetylglucosamine (GlcNAc), and exposure of GlcNAc leads to ingestion of platelets by THP-1 cells, and by macrophages.
  • GlcNAc can potentially be further removed, exposing the mannose residues.
  • the mannose residues can be readily recognized by macrophage mannose receptors, triggering immediate platelet clearance.
  • Example 20 Improved in vitro quality of human platelets stored in V-PASTM solution containing ⁇ -galactosidase inhibitor DGJ
  • Example 19 Data described in Example 19 demonstrated that loss of ⁇ -galactose from platelet surface leads to increased ingestion of platelets by a M P2-expressing THP-1 cells. Whether inhibition of ⁇ - galactose loss from platelet surface during platelet storage may improve the the quality of stored platelets was tested. Platelets were stored in plasma/V -PASTM solution in a ratio of 30:70, in the absence or presence of ⁇ -galactosidase inhibitor DGJ (1-deoxygalactonojirimycin), and analyzed the stored platelets over the course of storage.
  • DGJ 1-deoxygalactonojirimycin
  • V-PASTM solution is used herein to refer to a platelet additive solution having a silaidase inhibitor, and one or more storage medium components (e.g., not having a ⁇ -galactosidase inhibitor).
  • V-PAS+TM solution is used herein to refer to a platelet additive solution having a silaidase inhibitor, a ⁇ -galactosidase inhibitor, and one or more storage medium components.
  • the terms V-PAS or V-PAS+ can be shown with or without the "-" as VP AS or VPAS+, respectively.
  • the platelet aliquots were sampled on Day 1, Day 5, Day 7 or Day 9 and diluted with PBS.
  • the diluted platelets were stained with FITC-labeled Annexin V for PS exposure, or FITC- labeled CD62P antibodies for P-selectin exposure, and analyzed by flow cytometry.
  • PS Phosphatidylserine
  • apoptosis phosphatidylserine is no longer restricted to the cytosolic part of the membrane, but becomes exposed on the surface of the cell.
  • Fresh isolated platelets have little, but readily detectable, surface exposure of PS, which can be measured by Annexin V binding.
  • PS exposure on platelet surface is increased. Increased surface exposure of PS on stored platelets has been correlated with reduced platelet recovery after transfusion. The platelet PS surface exposure during platelet storage was monitored under different conditions at the indicated time points in Fig. 47A, 47B, 48A, and 48B.
  • Fig. 47A platelets stored in 100% plasma (Plasma Platelet) demonstrated a continuous increase in PS exposure, as measured by Annexin V binding, which is (roughly) linearly proportional to the storage time. As expected, platelets stored in both plasma and V-PAS (V-PAS
  • V-PAS+ solution shows a similar impact on platelet surface exposure of PS up to Day 5 as compared to V-PAS platelets (i.e., without DGJ).
  • V-PAS+ inhibits accelerated PS exposure, as compared to that seen in platelets stored in the presence of V-PAS (See V-PAS+ Platelet in Fig. 47B).
  • P-selectin expression i.e., platelet granule secretion
  • platelet granule secretion is used to evaluate the quality of stored platelets. Its expression on the platelet surface is independent of PS exposure.
  • the dramatic down-regulation of PS exposure on V-PAS+ Platelets compared to Plasma Platelets led us to examine how V-PAS+ impacts the platelet activation after storage for 9 days. As shown in Fig. 48B, V-PAS+ has significant negative effect on the P-selectin exposure on platelets stored for 9 days compared with plasma, indicating that platelets stored in V-PAS+ have less platelet activation than those stored in 100% plasma.
  • DGJ can effectively preserve the quality of human platelets, i.e., reduce platelet apoptosis, and platelet activation, when stored in 30% plasma and in the presence of a platelet additive solution.
  • a ⁇ -galactosidase inhibitor such as DGJ can be used as an effective component in PAS formulations for platelet storage by inhibiting the galactosidase activity, thereby reducing damages to platelets caused by glycan deterioration.
  • V-PAS+ includes a ⁇ -galactosidase inhibitor as well as a sialidase inhibitor.
  • V-PAS+ includes DGJ as the ⁇ -galactosidase inhibitor and DANA as the sialidase inhibitor. Platelet numbers were adjusted prior to transfusion to ensure equal numbers of transfused platelets per condition. Fresh platelets were kept in 100% plasma and transfused immediately after isolation.
  • Isolated platelets were labeled with 2.5 ⁇ of CMFDA for 15 min. Following staining, platelets were pelleted and resuspended in 500 ⁇ of plasma, V-PAS/Plasma (70:30) or V-
  • PAS+/Plasma (70:30). Platelets were stored for 20 hours at room temperature and transfused into 8 weeks old syngeneic mice. Non-stored fresh platelets in plasma were used as controls. Platelet survivals were determined by intravenous injections CMFDA-labeled mouse platelets, as described in Rumjantseva V., et al, "Dual roles for hepatic lectin receptors in the clearance of chilled platelets", Nature Medicine 15(11): 1273-80 (2009) and Sorensen A.L., et al, "Role of sialic acid for platelet life span: exposure of beta-galactose results in the rapid clearance of platelets from the circulation by asialoglycoprotein receptor-expressing liver macrophages and hepatocytes", Blood 114(8): 1645-54 (2009).
  • Fig. 49 Short-term (2 hours) and long-term (48 hours) survivals of the transfused platelet populations are shown in Fig. 50.
  • Peptide Nap-FFG was dissolved in DMSO or solvent of choice at 50-200 mg/rnL and diluted to 1 mg/mL with PBS containing 2-10 mM Na 2 C0 3 before use. Platelets suspended in 100% plasma or 30% plasma/70%) platelet additive solutions were treated with the peptide at 0.01— 0.2 mg/mL, or vehicle alone for 5-30 min at room temperature. Aliquots were removed from the peptide- or vehicle-treated platelet samples for analysis, and the rest were stored under different conditions or PEGylated as described in Example 23. The peptide-treated platelets were analyzed before and after storage in comparison with the vehicle-alone-treated platelets.
  • the binding of the peptide to platelets were assessed by measuring the disappearance of peptide from the storage media, and/or the amount of peptide directly associated with the platelets. Briefly, a sub-aliquot of the peptide-treated platelet sample was centrifuged for 5 min at 1000 xg in the presence of Prostaglandin El (PGE1). The supernatant was transferred to a new tube and residual platelets removed by centrifugation for 5 min at 15,800 xg with a bench top Eppendorf centrifuge. The platelet-free supernatant was subsequently heat-treated, clarified by centrifugation, and analyzed by LC-MS and/or HPLC for the presence of peptide.
  • PGE1 Prostaglandin El
  • the platelet pellet was washed 2 times with PBS, resuspended in DMSO, and sonicated or heat treated (5 min at 100 °C) to release platelet-bound peptide. Following clarification by centrifugation for 5 min at 15,800 xg, the released peptide was analyzed by LC-MS and/or HPLC. Formation of hydrogel:
  • the Zeta potential of peptide-treated platelets was measured to verify the formation of hydrogel layer over the platelets using a Zetasizer or an equivalent. The measurements were performed automatically using aqueous dip cells.
  • Platelet activation was assessed by measuring the surface expression of P-selectin. Briefly, platelets (2xl0 7 platelets/mL) were incubated in dark with FITC-CD62P (BD Bioscience, 1 :200 dilution) in PBS for 30 min at RT, diluted 5-fold in PBS and analyzed by flow cytometry.
  • FITC-CD62P BD Bioscience, 1 :200 dilution
  • TRAP- 14 thrombin receptor activating peptide with 14 amino acids
  • Platelet function reserve is a measurement that indicates the potential of platelets to become activated after storage. It can be determined by measuring the increase in P-selection expression after platelet activation with an agonist as described above.
  • Integrin beta-3 (P3)/CD61, CD9, or others perform similarly as described in 'Platelet activation" using corresponding antibodies.
  • Platelets can be effectively hydrogelated without being activated while preserving the function, as compared with platelets treated with vehicles.
  • the data indicate that platelets can be safely encased in a negative-charged shell without compromising their functions.
  • the hydrogelated platelets demonstrated comparable or improved functions compared with the vehicle-alone -treated platelets.
  • Example 23 Non-covalent PEGylation of hydrogelated platelets
  • PEGylation has been used to immunocamouflage red blood cells.
  • PEGylated platelets in which PEG forms covalent bonds with the platelet membrane have also been described by others, allowing platelets to be stored at about or below 0°C.
  • covalent chemistry was exclusively used by others in these PEGylations.
  • FITC Fluorescein isothiocyanate
  • NTA nitrilotriacetic acid group
  • PLL-g-PEGs can be synthesized in-house or obtained from suppliers.
  • PLL(15- 30KDa)-g-PEG(2KDa) can be prepared from Poly-L-lysine (PLL) in the hydrobromide form (MW 15 000 to 30 000 g mol-1, polydispersity index; 1.1 to 1.5, Sigma) and methoxy-terminated PEG
  • Hydrogelated platelets prepared as described above can be mixed directly with cationic PLL- g-PEG at concentrations of 0.005-1 mg/mL, and incubated for 1-60 min with gentle shaking. The resulting platelet mixtures can be analyzed and stored under different conditions.
  • the cationic PLL-g-PEG-treated platelets can be analyzed before and after storage in comparison with the vehicle-alone-treated platelets using methods as in Example 22.
  • function assays can be carried out on platelets before and after storage.
  • Platelet aggregation can be measured with an Aggregometer (Chrono-Log Corporation). Platelets can be adjusted to a concentration of 300,000 cells/ml with autologous platelet-poor plasma (control) or platelet samples.
  • a thrombin aggregation assay can be performed using thrombin (1.0 U/ml final concentration) and GPRP (2.5 mM final concentration). Duplicate measurements can be done for each test.
  • a ristocetin agglutination assay can be carried out using ristocetin (1500 ⁇ g/ml final concentration). Aggregation and agglutination results can be measured as a percentage of maximum light transmittance as determined by platelet-poor plasma. Using AGGRO/LINK the slope and amplitude of the generated curves can be computed. Other similar assays can also be used.
  • the anionic hydrogelated platelets can be effectively PEGylated/coated with cationic PLL-g- PEG as demonstrated by the drop of ⁇ -potential, and reduction of the platelet surface marker CD9.
  • PEGylation when PEGylation is carried out in a non-covalent fashion, as describe herein, it acts as an excellent cryoprotectant and it does not alter the blood coagulation properties of the platelets.
  • the self- forming hydrogel-directed non-covalent PEGylation provides a simple, practical and effective approach for improving platelet storage. This application relates to U.S. Application No.

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Abstract

L'invention concerne une solution additive plaquettaire (PAS) ayant au moins un peptide formant un hydrogel à auto-assemblage sans aucun ou avec l'un ou l'autre ou les deux parmi un ou plusieurs inhibiteurs de sialidase et un ou plusieurs inhibiteurs de β-galactosidase ; éventuellement un ou plusieurs agents de modification de glycane ; un ou plusieurs constituants PAS qui comprennent un sel, une source de citrate, une source de carbone ou n'importe quelle combinaison de ceux-ci. La PAS présente éventuellement, comme partie de la même solution ou comme solution séparée, une seconde solution additive plaquettaire ayant un ou plusieurs polymères cationiques sans aucun ou avec l'un ou l'autre ou les deux parmi un ou plusieurs inhibiteurs de sialidase et un ou plusieurs inhibiteurs de β-galactosidase ; éventuellement un ou plusieurs agents de modification de glycane ; un ou plusieurs constituants PAS qui comprennent un sel, une source de citrate, une source de carbone ou n'importe quelle combinaison de ceux-ci.
PCT/US2014/013777 2013-01-30 2014-01-30 Solution additive plaquettaire ayant un peptide formant un hydrogel à auto-assemblage WO2014120886A1 (fr)

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US20170246237A1 (en) * 2014-10-09 2017-08-31 University Of Strathclyde Self-assembling tripeptides
CN108064171A (zh) * 2015-03-17 2018-05-22 参天制药株式会社 含有多肽的医药组合物
CN109957000A (zh) * 2017-12-14 2019-07-02 南开大学 一种促进细胞增殖的多肽衍生物及其制备方法及应用
CN114376965A (zh) * 2021-12-24 2022-04-22 南开大学 促进肿瘤血管正常化和放疗增敏的一氧化氮水凝胶及其制备方法
WO2023211988A3 (fr) * 2022-04-25 2024-03-14 Duke University Compositions et procédés d'immunothérapie active anti-phosphocholine

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