WO2003013615A1

WO2003013615A1 - Electroporative delivery of molecules to organs

Info

Publication number: WO2003013615A1
Application number: PCT/US2002/024285
Authority: WO
Inventors: Robert W. Malone; Ralph Schmid; Bartosz Kubisa; Aima Uduehi; Erick Lawir Ayuni; Joseph Drabick; Jill Glasspool-Malone
Original assignee: Malone Robert W; Ralph Schmid; Bartosz Kubisa; Aima Uduehi; Erick Lawir Ayuni; Joseph Drabick; Jill Glasspool-Malone
Priority date: 2001-08-07
Filing date: 2002-08-02
Publication date: 2003-02-20

Abstract

The present invention relates to the electroporative delivery of a polynucleotide or other bioactive molecule, such as a drug or therapeutic protein, into cells of an organ, without injecting the molecule directly into the organ. Instead, the molecule is delivered by means such as instillation or catherization through an epithelially- or endothelially-lined lumen connected to the organ. Thus, the inventive method combines administering a molecule to an organ and electroporation of that organ to provide a method which facilitates entry of a molecule into cells of an organ while preserving organ function and integrity.

Description

ELECTROPORATIVE DELIVERY OF MOLECULES TO ORGANS

FIELD OF INVENTION

The present invention relates to the electroporative delivery of a polynucleotide or other bioactive molecule into cells of an intact organ by means of an epithelially- or endothelially-lined lumen connected to the organ.

BACKGROUND OF THE INVENTION

An inability to deliver a therapeutic agent across a cell membrane has profound consequences upon the effectiveness of a drug, vaccine, or gene-therapy treatment. Substances that potentially can remedy or cure a cellular abnormality, an acquired or inborn disease, or a genetic aberration may be rendered ineffective if they cannot traverse a cell membrane, to modify a biological or genetic trait.

Consequently, procedures that aid the flow of a drug or gene into a cell are highly sought after, as are molecules that help transport therapeutic agents across the membrane barrier. These delivery methods, however, are far from ideal and, in some cases, are harmful. Viral-based treatments, for example, exhibit low delivery efficacy and are potentially toxic. Thus, administering adenoviral gene therapy vectors to the lung causes pronounced inflammation and pulmonary edema. Yang et al., J. Virol. 69: 2004 (1 995). The presence of relatively few adenoviral receptor molecules on the surface of the lung epithelium also means that only a small number of vectors can be taken up by the cell. Non-viral therapeutic treatments fare no better because inefficiency, in vivo "clearance," inflammation, and the complexities of preparation and manufacture compromise their utility. See Yew et al., Human Gene Therapy, 1 0(2):223-34, (1 999). Attempting to overcome these drawbacks, investigators have pursued ways to modify a cell membrane so as to ease the passage of molecules into the cell. An advance in this regard came with the showing that a cell membrane can be permeabilized temporarily when subjected to electrical pulses, which open pores in the membrane. Although this phenonemon was recognized in the mid-60s, nearly two decades passed before an electroporative technique was employed to effect the passage of DNA into cultured cells. Since then, introducing polynucleotides into cells via in vitro electroporation, that is, by applying a plurality of electrical pulses, has become a common laboratory practice. See Coster, Biophys J. ,

5(5):669-86, (1 965); Sale & Hamilton, Biochim Biophys Ada., 1 48:781 - 788, (1 967); Sale & Hamilton, Biochim Biophys Acta., 1 63(1 ):37-43, (1 968); Neumann et a/., EMBO J., 1 (7):841 -5, (1 982); Potter et al., Proc Natl Acad Sci U S A., 81 (22):71 61 -5, (1 984); Fromm et al., Proc Natl Acad Sci U S A., 82(1 7):5824-8 (1 985); Toneguzzo & Keating, Proc Natl Acad Sci U S A., 83(1 0):3496-9 (1 986); Tur-Kaspa et al, Mol Cell Bio/., 6(2):71 6-8 (1 986).

The routine application of this technique masks an elaborate set of molecular interactions and events. When cells are exposed to an electric field, cellular transmembrane potentials are focally increased. As such, ions and soluble dipole molecules within cells orient themselves with respect to electrical field lines such that the distribution of charged molecules becomes polarized. Consequently, one side of the cytoplasm becomes relatively positive and the other side more negatively charged. In any event, this sequence of events brings about local structural deformalities that result in temporary openings and/or increased permeability in the affected cellular membrane. The cells of an organ, just like cultured cells in vitro, may be similarly electroporated. Depending on the properties of each pulse, the pulsing regime employed and the type of electrodes used to deliver pulses, an organ may be subjected to a variety of electrical field strengths. Consequently, a single or multiple layer of cells may be electroporated in localized or more widespread regions of the organ tissue.

Researchers are attracted to this basic concept and use electroporation to deliver DNA, genes and other polynucleotides across the cell membrane, without having to counter the potentially harmful effects of viral carriers. Of particular interest to researchers, for example, is the ability to deliver therapeutic polynucleotides and chemotherapeutic agents to intact tissues for the treatment of diseases and disorders. Cells of the liver, heart, skeletal muscle, and skin have been electroporated in the context of effecting delivery of bioactive molecules. For instance, Heller et al, FEBS Lett., 389(3):225-8 (1 996), succeeded in getting plasmid DNA into cells of an exposed rat liver by injecting the genetic material into the tissue and applying pulses via a circular array of six needles stuck into the organ. Injecting genetic material directly into an organ, prior to electroporation, is typically how DNA is introduced into cells of an organ. Studies indicate that this step-wise procedure - direct injection followed by application of electrical pulses — increases the uptake of DNA by 1 0- to 1 000-fold. See Mir et al., C R Acad Sci III., 321 (1 1 ):893-9 (1 998); Heller et al, Adv. Drug Deliv., 35: 1 31 -1 37

(1 997); Somiari et al., In SUBCUTANEOUS GENE THERAPY (L. Taichman, Ed.) Natcher Conference Center, National Institutes of Health, Washington, D.C. (2000). So-called "penetrating" or needle electrodes represent one of many electrode types that can be used, in principle, to deliver electrical pulses to tissues. The "caliper" electrode, for instance, is characterized by its placement on an organ surface, whereas a "catheter" electrode is fed through internal vessels to deliver electrical pulses. Accordingly, existing methods typically involve the injection of some substance directly into an organ and then the application of a number of high, or low voltage, electrical pulses. Predictably, investigators place electrodes at the site of injection and then initiate the pulsing regime. Those electrodes may be placed on the surface (such as caliper electrodes), or stuck into (such as needle electrodes) the organ. Consequently, both the act of injecting and the electroporation can damage both the organ tissue and the degrade the substance being administered, such as a gene construct.

For example, even though electrical pulses can be applied to a tissue by a assortment of different electrode designs, they can all wind up damaging an organ tissue. Thus, the therapeutic applications of electroporation have been marred because preserving the integrity and function of an organ can be problematic. Electrically pulsing lung tissue, for example, can trigger a wide range of adverse biological effects, such as excessive pulmonary edema, reactive hyperemia and diffuse coagulation. The intense, focused nature of the electric field around edges of certain electrodes also may burn and scar the tissue surface. There also are concerns relating to cardiac arrest, nervous tissue toxicity, and hemodynamic and vascular-permeability changes. In addition, an individual may experience pain or other neurological effects, associated with depolarization, when high voltages are employed. Consequently, the potentially harmful events of high-voltage, pulsed electrical fields detract from their utility in the lung or other internal organs. For example, see Tung et al., Ann N Y Acad Sci., 720: 1 60-75 (1 994); Lee, Curr. Probl. Surg., 34(9):677-764 (1 997). In addition, injection of a substance directly into the parenchyma of an organ, further damages cells as well as the surrounding tissue. An injection needle can damage cells around the site of injection and may cause them to release nucleases, which can degrade an administered therapeutic gene. DNA that is simply injected into an organ ("free DNA") is susceptible to extracellular and intracellular nuclease-mediated degradation in addition to the released nuclease activity of damaged cells. See Barry et a/., Human Gene Therapy, 1 0(1 5):2461 -80 (1 999). The damage can be more widespread, when multiple sites on the organ are injected and electroporated. Thus, existing methods do not rely on the delivery of a substance into an organ by routes other than direct injection. Thus, the field lacks a way to administer a molecule to an organ that does not involve injection into the organ tissue and whereby the electroporation of an organ, specifically the lung, does not compromise the function of the organ tissue or cause tissue damage.

SUMMARY OF THE INVENTION

Accordingly, the instant invention relates to the electroporative delivery of a polynucleotide or other bioactive molecule, such as a drug or therapeutic protein, into cells of an organ, without injecting the molecule directly into the organ. Instead, the molecule is delivered by means such as instillation or catherization through an epithelially- or endothelially-lined lumen connected to the organ. The inventive method combines such methods of administering a molecule to an organ with the electroporation of that organ, in order to provide a method which facilitates entry of a molecule into cells of an organ while preserving organ function and integrity.

In one embodiment, the present invention provides a method for introducing a molecule of interest into a cell of an intact organ, or part thereof, by administering the molecule via an epithelially-lined or endothelially-lined lumen which is connected to the organ and applying a plurality of electrical pulses to the organ via at least one pair of electrodes. The pulses are sufficient to electroporate at least some cells of the organ. The plurality of electrical pulses are generated by electrodes selected from the group consisting of, but not limited to, caliper, needle, penetrating, non-penetrating, tweezer, paddle, catheter, electroporation tank, implantable and conductive bag electrodes. In one aspect of the present invention, the electrical pulses are delivered through an externally exposed surface of the organ. In another aspect, the electrical pulses are delivered through an internal surface of the organ. Further, the electrical pulses are delivered to between an internal surface and externally exposed surface of the organ. In one embodiment of the instant invention, the organ is a lung, heart, liver, pancreas, kidney, or brain. According to one aspect of the instant invention, the organ is not surgically exposed from the individual. In another aspect of the invention, the organ, or a part thereof, is surgically exposed. In yet another aspect, the organ, or a part thereof, is removed entirely from the individual.

In another embodiment of the instant invention, the molecule of interest is selected from the group consisting of, but not limited to, a polynucleotide encoding a protein or a peptide, a drug, a therapeutic protein or a peptide, an antisense polynucleotide, a diagnostic agent and a virus. In a preferred embodiment, the polynucleotide encoding a protein or a peptide comprises a polynucleotide sequence selected from the group consisting of the erythropoietin gene, Factor VIII gene, elastase inhibitor gene, protease inhibitor gene, alpha-1 anti-trypsin gene, CFTR gene and a DNase gene. In another embodiment, the polynucleotide sequence is operably linked to at least one regulatory element present in a plasmid. Furthermore, the plasmid comprises sequences necessary to induce homologous or non-homologous recombination events in the host genome, wherein the polynucleotide becomes integrated into the genome of a cell. In one embodiment, the drug is selected from the group consisting of a chemotherapeutic drug, an anti-inflammatory drug, an antitumor drug, a diuretic, a hormone and immunosuppressive drug. In a preferred embodiment, the immunosuppressive drug is selected from the group consisting of, but not limited to, azathioprine and cyclosporine.

According to another aspect, the molecule is selected from the group consisting of an antibiotics, sulfonamides and antiviral zidovudine. The drug may be one that is used to treat the heart and blood and may selected from the group of consisting of, but not limited to, antiarrhythmics, cardiotonics, vasodilators, anticoagulants and thrombolytics. In a preferred embodiment, the cardiotonic drug is digoxin or digitoxin. The vasodilator drug preferably is selected from the group consisting of, but not limited to, sosorbide dinitrate, nitroglycerin, calcium channel blockers and beta-blockers. In another preferred embodiment, the anticoagulant is selected from the group consisting of, but not limited to, heparin and warfarin. The thrombolytic drug is preferably selected from the group consisting of, but not limited to, plasminogen activator and streptokinase. The antihyperlipidemic drug is selected from the group consisting of, but not limited to, lovastatin, gemfibrozil, and pravastatin. In another aspect of the invention, the molecule may be a synthetic or recombinantly-produced therapeutic protein or peptide which facilitates transplantation, reduces acute or chronic transplant rejection, or ameliorates symptoms associated with inborn errors of metabolism or acquired disease. In a preferred embodiment, the synthetic or recombinantly-produced therapeutic protein or peptide is selected from the group consisting of, but not limited to, TGF-β, IL-10, and CTLA4-Ig. In another embodiment, the synthetic or recombinantly-produced therapeutic protein or peptide can be modified so it can be transported to a specific cell type. In yet another embodiment, the synthetic or recombinantly-produced therapeutic protein or peptide is conjugated or recombinantly fused to a cell-specific peptide signal sequence in order to direct the molecule to cells of a specific organ. In a preferred embodiment, the synthetic or recombinantly-produced therapeutic protein or peptide is conjugated, or recombinantly fused to a polyanionic peptide, wherein the polyanionic peptide improves the water- solubility of the therapeutic protein or peptide.

In yet another aspect of the present invention, the molecule of interest is administered to the organ in an administering solution. In one embodiment, the administering solution is electrolytic, isotonic, hypotonic or hypertonic. In another embodiment, the administering solution further comprises a co-factor selected from the group consisting of, but not limited to, aurintricarboxylic acid and dexamethasone. Furthermore, the administering solution may comprise a protein which promotes wound healing, selected from the group consisting of, but not limited to, platelet- derived growth factor, vascular endothelial growth factor, insulin-like growth factor, epidermal growth factor, basic fibroblast growth factor and endothelial derived growth supplement.

The internal or external surfaces of the organ may also be pretreated with a cleansing solution. "Pretreating" means an organ is treated with a cleansing solution before the molecule of interest is administered and prior to electroporation of the organ. In one embodiment, the cleansing solution further comprises n-acetyl cysteine or DNase. In yet another aspect of the instant invention, the administering of the molecule of interest to an organ is performed through an epithelially-lined or endothelially-lined lumen by aerosolization, inhalation, intratracheal instillation, catherization, intraparenchymal administration, vascular perfusion, particle bombardment, topical preparations, or bronchoscopic administration. The skilled artisan would be aware of other administering techniques that may be used to administer a molecule of interest to an organ. In a preferred embodiment, the epithelially-lined lumen is an airway tract. In another preferred embodiment, the endothelially-lined lumen is a blood vessel or a lymphatic vessel.

In a preferred embodiment, the electrical pulse comprises a voltage with electrical field strength of between about 200 to about 500 V/cm of variable frequency and duration. In another preferred embodiment the electrical pulse further comprises (a) a field strength between 200-500 V/cm, (b) a frequency of 1 Hz, and (c) a duration of between about 5 ms and 20 ms. More preferably, the voltage is 300 V/cm. Preferably, the duration is 1 0 ms. Preferably the number of pulses administered to an organ is between from about 2 to about 1 0 pulses. In a more preferred embodiment, the number of pulses administered to an organ of the instant invention is four pulses.

The instant invention also provides a method for preparing an organ or part thereof, for transplantation, comprising: obtaining an organ; treating the organ with a cleansing solution administered through a lumen connected to the organ; perfusing the organ with an administering solution comprising an immunomodulatory compound and electroporating the organ, wherein the cleansing step washes internal regions of the organ and wherein the electroporating step is performed by delivering a plurality of electrical pulses to the internal and external surfaces of the organ.

According to one embodiment of the instant invention, the intact organ is a human organ. In yet another embodiment, the intact organ may be a nonhuman organ destined for xenotransplantation. According to yet another aspect of the instant invention, a molecule of interest is delivered in utero using transaminotic delivery methods known to those of skill in the art. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In studying the problem of delivering bioactive molecules to cells of an organ by other than by direct injection, the present inventors developed an approach that avoids drawbacks that plague conventional electroporative delivery techniques. Thus, the inventive method combines administering a molecule of interest to an organ with electroporation of that organ, thereby to facilitate entry of the molecule into cells of the organ while preserving organ function and integrity. The present invention does not encompass injecting a molecule directly into the tissue of an organ. Rather, a technique according to the present invention includes delivering a bioactive molecule through an epithelially- lined or endothelially-lined lumen connected to an intact organ, followed by subjecting the organ to electrical pulses to effect electroporation without damaging organ tissues. The approach of the present invention entails electrically pulsing external or internal surfaces (or both) of an organ, which can be applied to a wide range of organs, in many species. Further, the inventive methodology can be used to prime organs immunologically, prior to transplantation, as well as to treat disease or to cause the up-regulation, production and secretion of proteins in the organ. The inventive method may be used to administer a variety of molecules which function to repair, treat or modify a disease or trait associated with a particular organ or the host individual. For instance, the electroporative method may be useful in treating cancer and acquired diseases, such as emphysema, or in correcting inborn errors of metabolism, such as cystic fibrosis. Allergen-mediated and infectious agent-mediated inflammatory disorders can also be countered by administering molecules which stimulate immune responses to such infectious agents. The inventive method also may be useful in expressing a protein that is capable of reducing the immunologic sequalae associated with transplantation, or which helps facilitate tissue growth and regeneration. Furthermore, secreted proteins such as an erythropoietin, cytokine or serum leucoproteinase inhibitor, antibodies or fragments thereof may be administered using the inventive technique. Optionally, a surfactant or an anti-inflammatory drug can be used to ameliorate electroporation-associated damage or the immunological sequalae thereof. Such a secondary substance may be administered independently or simultaneously with a bioactive molecule.

Pursuant to the present invention, a molecule is administered by one of several methods other than direct injection that targets a specific organ. After that, the organ is electroporated in one of a number of ways. For instance:

(1 ) An organ, or a portion of it, can be exposed by surgical procedure, pulsed under electroporation conditions and returned to its original position in vivo.

(2) Alternatively, an organ can be removed entirely from an individual, before or after electroporation, for the purposes of preparing it for for transplantation. In this case, the donor organ may be treated with an immunosuppressive substance, such as cyclosporine, in order to reduce rejection of the graft by the recipient host.

(3) Or on the other hand, an organ need not be exposed surgically, but instead is electroporated internally, through the use of catheter electrodes fed through vessels connected to the organ such that electrical pulses may be delivered inside the organ. The range of organs contemplated by the present invention includes lung, kidney, heart, liver, and pancreas, but it is not limited to these. Thus, the term "organ" here denotes any differentiated structure, the cells and tissues of which perform a specific function in an animal or human. In principle, the present invention can be implemented with any organ to which an epithelially- or endothelially-lined lumen is connected, i.e., where the lumen can transport a fluid to or from the organ. Exemplary of epithelially-lined lumens is an airway lumen, such as the trachea or bronchial tract. The category of endothelially-lined lumens is illustrated by blood and lymphatic vessels. An organ also could be used as a source of diagnostic and functional research data. For instance, the biological function of proteins, peptides and polynucleotides or their affect upon endogenous genes and proteins can be investigated after electroporative delivery of such molecules to organ cells. The range of molecules that can be delivered to an organ includes, but is not limited to a drug, a therapeutic protein, a polynucleotide encoding a protein or a virus.

A "drug" can be a chemotherapeutic agent, an anti-inflammatory drug, or an immunosuppressive drug. Azathioprine and cyclosporine are exemplary of immunosuppressive drugs. Antimicrobial and antiviral drugs also may be administered according to the inventive technique, in order to fight infection. These include antibiotics, sulfonamides and antiviral zidovudine, (AZT). Drugs used to treat the heart and blood may also be administered using the present inventive method and include antiarrhythmics, cardiotonics, vasodilators and antihypertensives. Digoxin and digitoxin are examples of cardiotonic drugs. Exemplary of vasodilator drugs include sosorbide dinitrate, nitroglycerin, calcium channel blockers and beta-blockers. Antihyperlipidemic drugs lower levels of cholesterol and other blood lipids. Examples include lovastatin, gemfibrozil, and pravastatin. Anticoagulants, such as heparin and warfarin, help prevent blood clotting and also can be administered according to the present invention. Thrombolytic drugs, such as tissue plasminogen activator and streptokinase, are used to break up blood clots and also can be administered. Diuretics, hormones, antitumor drugs are further examples of molecules that can be administered to an organ. The class of "therapeutic proteins" that may be administered to an organ of the instant invention includes antibodies and synthetic- and recombinantly-produced proteins and peptides. For example, proteins or peptides which facilitate transplantation, reduce acute or chronic transplant rejection, or ameliorate symptoms associated with inborn errors of metabolism or acquired diseases can be administered by the inventive method. Illustrative of therapeutic proteins are TGF-β, IL-10, and CTLA4- Ig, each of which may be used to prime immunologically an organ which is to be transplanted. The drug or therapeutic protein may be modified to include a peptidic signal sequence in order to direct the molecule to cells of a certain organ. For instance a protein may be conjugated to a cell-specific peptide. The drug or therapeutic protein also may be conjugated, or recombinantly fused, to a polyanionic peptide so as to improve its water-solubility properties.

By means of the inventive methodology, any plasmid, RNA, or vector containing a protein-encoding polynucleotide can be introduced into a cell of an intact organ. The polynucleotide express a polypeptide, protein or transcript (RNA) that is useful in treating a disease or disorder. For example, a polynucleotide may encode a secretable protein such as erythropoietin, Factor VIII, an elastase inhibitor, protease inhibitor, alpha-1 anti-trypsin, viral particles or recombinant viral particles encoding transgenic proteins. In terms of polynucleotides particularly useful for treating abnormalities of the lung, such as cystic fibrosis and excessive mucus build up, one may administer a polynucleotide comprising in whole, or in part, the cystic fibrosis transmembrane conductance regulator (CFTR) gene or a DNase gene. The CFTR gene is defective in patients with cystic fibrosis, which causes a cell's calcium ion channels to function improperly. The instant invention contemplates administering a correct version of the CFTR polynucleotide, or an effective amount of purified CFTR protein or peptide into cells of an individual. Similarly, DNase protein or a DNase polynucleotide may similarly be administered to an organ be the inventive method. DNase is an enzyme used to break down mucus that builds up in the lungs of cystic fibrosis patients. During the course of that disease, white blood cells die while fighting off infections, releasing notoriously sticky DNA which contributes to the obstructive property of mucus. DNase acts to degrade that DNA and, in so doing, reduces mucus blockage. The present invention also contemplates the delivery of a DNase protein or peptide to an organ, such as the lung, in order to combat cystic fibrosis. In addition, a DNase polynucleotide may be introduced by the electroporative method of the instant invention into cells of an organ and expressed by endogenous or exogenous regulatory elements. A polynucleotide typically may encode a peptide or protein, such as those therapeutic proteins described above and be expressed by regulatory sequences contained in a plasmid. That is, a polynucleotide is inserted into a plasmid such that it is operably linked to regulatory sequences, such as a promoter, which drive the expression of a downstream polynucleotide. "Downstream" means a polynucleotide is 3'end to the promoter sequence. Illustrative regulatory sequences in this regard include a promoter, an enhancer element, a 5'-untranslated sequence favorable for expression in the tissue of interest, a 3'-untranslated region (a polyadenylation site, a terminator sequence, a targeting sequence that stabilizes or localizes an mRNA transcript, etc.), a transposable element, and splice donor and acceptor sequences. Indeed, any sequence which facilitates transcription, enhances transcript stability, processing and trafficking, or translation may be used. Examples also include inducible transcriptional elements that may be activated or suppressed by treatment with a low molecular weight compound (for example, tetracycline or analogs thereof). "Operably linked" means the gene is connected to regulatory elements, such as a promoter, 5' and 3' untranslated regions in such fashion that it can be efficiently transcribed and translated into its corresponding protein or peptide in either a constitutive or regulated fashion. Furthermore, a polynucleotide also may be operably linked to elements which facilitate integration of the polynucleotide sequence into a targeted or random locus of the host genome via homologous or non-homologous recombination events. Examples of such sequences include those derived from the genome and derivatives of the adeno-associated virus, as well as from transposons, such as the "sleeping beauty" transposon. The advantages of integrating the gene of interest into the host organ cell genome include providing more prolonged transgene expression than otherwise may be achieved. Thus, the polynucleotide encoding a protein or peptide, may be retained within the plasmid and expressed, or integrated into the host genome along with exogenous regulatory sequences and expressed thereafter. Alternatively, the polynucleotide may be integrated into the genome and expressed under the control of a native promoter and regulatory sequences. The skilled artisan would appreciate how to use standard molecular biology techniques to create such plasmid constructs.

A virus, such as an adenovirus or retrovirus, may be administered to a lung of an individual according to the procedures outlined in the inventive method. Furthermore, a virus may be administered to an organ other than a lung. In addition to delivering a polynucleotide encoding a protein or peptide, the inventive method also envisions administering a polynucleotide that can be used in antisense or ribozyme therapies. Antisense therapy involves introducing an antisense copy of a polynucleotide sequence that will hybridize with that polynucleotide's messenger RNA transcript once it is expressed. This hybridization typically prevents the transcript from being translated into a protein, or initiates a degradation pathway that destroys the RNA molecule.

The Applicants' invention also may be used to deliver a diagnostic agent to the cells of an organ. A "diagnostic agent" can be a protein (or its encoding polynucleotide) that is used to detect or isolate transformed cells. For example, a diagnostic agent could be a green fluorescent protein or luciferase protein, which illuminates a cell; or a protein which enables detection via positron emission tomography. Alternatively, a diagnostic agent may be a protein recognized by an antibody or fragment thereof or which is recognized by a polynucleotide aptomer. The inventive method further contemplates administering any protein that is recognized, directly or indirectly, by an imaging device or technology. Thus, the inventive method envisions administering a molecule of interest, such as a drug, protein or peptide, polynucleotide or diagnostic agent, by a route other than direct injection, into the cells of an organ, prior to, or after electroporation of that organ.

It also may be useful or necessary to add co-factors to the preparation of the molecule of interest so as to enhance its stability or its therapeutic properties. In this regard, the molecule of interest is delivered to an organ in the form of an "administering solution." The administering solution may be isotonic, hypotonic or hypertonic and may include ions, non-ionic surfactants or other compounds which are physiologically beneficial to the integrity of the organ's cells. The administering solution may also function as an electrolyte for the purpose of conducting an electric field through to internal cavities of an organ.

The administering solution may further comprise other cofactors. For example, in the case of delivering a polynucleotide, the administering solution may contain an agent to help reduce degradation of the polynucleotide. For instance, nuclease inhibitors like aurintricarboxylic acid (ATA) may be coadministered with a polynucleotide. The administering solution may comprise a surfactant and/or an anti- inflammatory agent such as dexamethasone. The administering solution may further comprise factors which promote wound healing. Such factors include, but are not limited to platelet-derived growth factor, vascular endothelial growth factor, insulin-like growth factor, epidermal growth factor, basic fibroblast growth factor and endothelial derived growth supplement.

The administering solution also may comprise factors that have been shown to promote healing of tissues subjected to electrical trauma. See U.S. patent 5,605,687 to Lee et al. For instance, the administering solution may comprise a surface active polymer such as a poloxamer, a meroxapol, a poloxamine or a polyol. Such surface active polymers may exist as either a fluid or solid (gel) at one temperature and then assume an alternate phase at another temperature. Such alternative forms of a surface active polymer may be used to facilitate localization or infusion of the administering solution into a tissue or tissue surface during treatment. An administering solution comprising a poloxamer, a meroxapol, a poloxamine or a polyol may also be delivered locally or systemically after electroporation to reduce any tissue damage. In addition, antibiotic compounds such as colistin, neomycin and polymyxin B, may be added to the administering solution, Ionic amphiphilic detergents also may be incorporated, as well as polymeric polynucleotide-binding agents. The administering solution may further comprise a high-energy phosphate, such as free ATP or ATP-MgCI₂ or potassium salts of ATP and a high energy phosphate regeneration molecule, such as phosphocreatine. The MgCI₂ acts to prevent chelation of divalent cations and dephosphorylation of ATP so that when it is administered in equimolar amounts with ATP, the concentration of ATP available to the cell is higher than simple free ATP. When a cell membrane is porated, the ATP store is often depleted, leading ultimately to cell death. By including ATP, ATP-MgC and phosphocreatine in the administering solution, one may balance cellular energy requirements. Likewise, the damaging consequences of efflux other ionic species normally concentrated within cells (such as potassium ions) through electroporation-induced pores may be ameliorated by adding an appropriate concentration of such ionic species to the administering solution. The effects of influx of other damaging ionic species down concentration gradients into cells (such as calcium ions) may also be ameliorated by modifying the administering solution to be deficient in such ions or to include molecules such as chelating agents (for example EGTA) that may specifically reduce local concentrations of such ions. When used herein to describe the administration of a "molecule" or "molecule of interest," one of skill in the art would understand that it is an administering solution comprising the molecule that is administered to an individual.

The administering solution can be delivered to an individual by methods known to those skilled in the art, including, but not limited to, aerosolization, inhalation, intratracheal instillation, catherization, vascular perfusion, particle bombardment, topical preparations, and bronchoscopic administration. Alternatively, the administering solution may be formulated into a dry, powder form or into a tablet or pill. Such methods deliver the administering solution to an organ either through an epithelially-lined lumen or an endothelially-lined lumen that is connected to the organ. Thus, the administering solution may be injected into a blood vessel that supplies an organ. For instance, the administering solution may be injected into the pulmonary artery that leads into the heart. In contrast, the inventive method does not encompass injection of the administering solution directly into the tissue of an organ. The administering solution may be introduced into the organ via a route independent of that by which the molecule of interest is delivered. For instance, the administering solution may be inhaled, whereas the molecule of interest is delivered via a catheter. Further, an administering solution without a molecule of interest, may be instilled through an airway lumen, while another administering solution containing a molecule of interest is introduced into a vascular lumen.

(a) Inhalation

For administration by inhalation, the administering solution can be conveniently delivered in the form of an aerosol spray from a pressurized pack or a nebulizer, with the use of a suitable propellant, such as dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas. In the case of a pressurized aerosol the dosage unit can be determined by providing a valve to deliver a metered amount. Capsules and cartridges of gelatin, for example, for use in an inhaler or insufflator, can be formulated containing a powder mix of the molecule of interest and a suitable powder base such as lactose or starch.

(b) Instillation

Delivering a molecule of interest to an organ may also be achieved by instilling the administering solution. The lung, for example, is accessible through the trachea. In this regard, instillation would involve injecting the solution directly into the trachea and bronchial tree lumen via intubation, followed by injecting a volume of atmospheric air to push the solution into various regions of the lung. Intubation involves inserting an endotracheal tube into the trachea of an individual. One of the two bronchi leading into a lung may be occluded with a removable clip so as to cause the administering solution to flow into one particular lung. The other lung may be ventilated. Alternatively, a double lumen endotracheal tube may be employed that provides for ventilation of one lung while lavaging, instilling an administering and/or electrolyte solution, and/or inserting a catheter or similar device that may include an electrode into the other lung.

(c) Catheterization

The intubation tube may also provide a convenient way by which to introduce a catheter into the lung. A "catheter," as used herein, is a flexible tube inserted into an epithelially-lined lumen or an endothelially- lined lumen, to transport fluids into or out of a targeted organ. A catheter may further include devices that enable visualization. For instance, the catheter may comprise a fiber optic device connected to an external monitor that allows the user to see inside the individual as the catheter is being passed through a lumen. Alternatively, radiographic dye may be injected through the catheter to vessels supplying the organ to determine the position of the catheter, or to visualize obstructions. The process of using a catheter to inject dye selectively into the coronary arteries, for example, is known as coronary angiography or coronary arteriography, and aids in the introduction of a catheter into the right side or the left side of the heart.

It is possible to target specific chambers of the heart with a catheter. For instance, a catheter may be inserted through the femoral vein or subclavian vein and passed into the right heart to measure the right atrial, right ventricular, pulmonary artery and pulmonlary capillary wedge pressures, oxygen saturation, and cardiac output. Similarly, a catheter inserted through the femoral artery or the brachial artery can be used to measure left heart aortic and mitral valve stenosis and regurgitations, as well as global and regional left ventricular functions and coronary ateriography. The administering solution may thus be delivered to specific regions of the heart by a catheter in similar fashion. The pancreas and liver provide other examples of an organ that can be accessed by a catheter. For instance, an I.V. catheter may be inserted into the common bilopancreatic duct by methods known to those in the art (Mallery S. et al., J.Med. Clin. North Am. 2000 September, 84(5): 1 059- 83;. Shah R.J. & Martin S.P. Current Gastroenterol. Rep. 2000 April, 2(2): 1 33-45). In the case of the liver, for instance, the hepatic duct is closed by applying a microvascular clamp to the hilum and plasmid DNA is injected through a catheter using an infusion pump. In addition to the liver and pancreas, a wide variety of organs may be similarly targeted with a catheter, including, but not limited to the bladder, heart, lung, kidney, brain and liver. Once the molecule has been administered to an organ by any one of the above-described methods, the organ may be surgically exposed and electroporated. Electrodes may be placed directly or indirectly onto the organ. They may be inserted into the organ via an electrode catheter or any other similarly minimally-invasive device, such as a laparoscope. Alternatively, the electrode could be wrapped around the organ. Thus, "contacting" an electrode with an organ encompasses a variety of procedures that may be employed to propagate an electrical field into the tissue of an organ. For instance, electrodes may be placed in contact with either external or internal surfaces of the organ tissue, or they be submerged in an electrolytic solution that itself in contact with a surface of the organ. In this regard, electrolyte solutions or gels may be used to bathe the internal or external aspects of an organ through which electrical pulses may be administered.

Several different types of electrodes may be employed to deliver an electroporative pulsing regime to an organ. The electrodes can be of any shape and arrangement. It may also be useful to sequentially alter the polarity and/or orientation of a series of administered electrical fields between different electrode pairs and/or groups such that the tissue between such electrodes experiences a series of electrical pulses of differing orientation. In addition, an electrode placed on an external surface of an organ may be of opposite polarity to an electrode placed inside the organ such that an electrical field is propagated both on the outside and inner depths of the organ tissue. Alternatively a pair of electrodes of opposite polarity may be applied to tissue adjacent to the organ such that the fields generated by such electrodes pass through the organ, as is typically performed clinically during cardiac defibrillation, for example.

(a) Non-penetrating electrodes

Thus, electroporation of an organ may involve placing two non- penetrating electrodes, such as the pair which comprise a "caliper" electrode system, onto the external surface of the organ. Each electrode of that pair may be parallel to one another and set a fixed distance apart. Variations in the distance between electrodes can distort the electrical field generated by them and so alter the success of electroporation. Thus, an important improvement of the present invention has been to incorporate small insulating "blocks" at the lateral and medial aspect of the caliper electrodes such that the distance between the electrodes is maintained and electrical field distortion reduced. Essentially, insulating tape is wound around the appropriate portion of the electrode so as to build a "nub" at that part of the electrode. When tape is wrapped around the equivalent spot on the other electrode, the distance between the electrodes is fixed. The spacing between the two non-penetrating electrodes of the present invention was maintained at two millimeters. A portion of the organ tissue is sandwiched between the tips of the caliper electrodes. The electrodes also could be flat, parallel strips of metal plates placed on the organ surface. Alternatively, a plurality of electrodes could be arranged in a circle such that the applied voltage electroporates the region of tissue within their circumference. With regard electroporating organs residing within the chest cavity, cardioversion paddles, commonly used intraoperatively in open heart surgery, could be used to electroporate heart muscle cells and the cells of organs residing within the chest cavity, without exposing those organs by surgery. It has been shown, for example, that cardioversion paddles placed on the chest can cause electroporation of heart muscle cells, but this observation has not been used to specifically deliver a molecule to a heart muscle cell. The present inventors have shown that uptake of a molecule by heart cells is greatly enhanced when cardioversion paddles are placed on the chest and electrical pulses delivered. In addition, "tweezer" electrodes, which are used to cauterize blood vessels can be used to practice the electroporative technique of the instant invention. Both in this specific case as well as in the general case of any such electrode device that is applied to tissue, it may be desirable to design such a device so that it will have rounded edges to diffuse the intensity of an electrical field around sharp corners and edges, which often burn and scar the surface of a tissue. (b) Penetrating electrodes

The electrodes used in the present invention also could be penetrating electrodes, whereby needle-shaped electrodes are stuck into the organ tissue before pulses are applied. The device may comprise a plurality of electrodes in any arrangement. That is, the electrode may comprise several needle-like tips arranged in some array, such as in a circle, for instance. In such an example, the imposed electroporating field may be alternated between different pairs of such tips, (c) Catheter, laparoscopic and endoscopic electrodes In addition, the catheter, laparoscope or endoscope used to deliver the administering solution to an organ, may further comprise an electrode. For example, electrodes may be affixed to the ends of a catheter, laparoscope or endoscope or, alternatively, an electrode is threaded through the lumen of the catheter, laparoscope or endoscope to its end. In one example, a small incision made in the skin, usually in the groin or neck area, through which a catheter is inserted. Typically, in the case of catherizing the heart, electrode catheters are used to conduct electrical impulses produced by the heart or to deliver small electrical impulses that induce, or bring on abnormal heart rhythms. For instance, a standard "bipolar catheter" can be placed in the right ventricle for delivery of an electrical pulse, or "shock." This technique allows for the observation of a condition, such as arrhythmia, under controlled conditions. On the other hand, the delivery of electrical pulses also permits one to readily electroporate heart cells. A catheter may comprise an electrode or a plurality of electrodes fixed to its outer surface so as to deliver electrical pulses to the internal areas of the organ. An electrode catheter used to deliver electrical pulses within the internal vestiges of an organ may also be treated with a coating of a "dielectric insulating material" such that the electrode may be used to administer an electrical field while minimizing current flux through the tissue.

Furthermore, an electrode catheter of the instant invention may be a balloon catheter that is modified to comprise electrodes placed on either side of the site of inflation. Typically, when the "balloon" of the catheter is inflated, it causes the sides of the catheter to swell and press against the sides of the lumen within which it is inserted. Consequently, electrodes on each side of such a balloon would be blocked from one another, with the occluding balloon acting as an insulator. Thus, when a voltage is applied to an inflated catheter, the electric field that normally would flow directly from one electrode to another through the lumen of the vessel is obstructed and winds up passing through adjacent tissue, such as through the vascular wall. This arrangement therefore forces the electrical field generated by the electrodes to be propagated into organ and surrounding tissue. Such an arrangement may be combined with a "double balloon" catheter wherein one electrode is fixed between the two balloons such that it is in electrical contact with a treatment substance administered by the catheter so as to reside between the two balloons, and one or more additional electrodes are placed distal to the space between the two balloons of the catheter. Such an arrangement may also be employed with a single balloon device such that an electrode is placed in the lumen of an endothelial or epithelial lined channel in a fashion so as to be distal to the balloon. In this fashion, conducting fluids, gels, or tissues proximal to the balloon may be partially or wholly insulated from any electrical pulses administered by such a device. Electrode catheters also may be used in conjunction with other types of electrodes, such as flat-plate, penetrating, gel-based or fluid electrolyte electrodes, which are applied to a surface of the organ.

(d) Patch electrodes

Patch electrodes are often used for transcutaneous nerve stimulation. However, they may also be used to deliver an electrical pulse to some area on the surface of an organ. The inventive method envisions the use of such an electrode to cause electroporation of cells in organ tissue.

(e) Electroporation tank

It would be useful to distribute a uniform electrical field in and around an organ, ex vivo. To accomplish this, a metal container filled with an electrolyte may used as an "electroporation tank" within which an organ may be submerged. By connecting the metal container to a pulse generator, the metal tank itself becomes an electrode, capable of delivering electrical pulses around the whole organ. The container may be made of an inert conducting material metal such as those used in the design of electrodes, like platinum or gold.

Before being placed into such a tank, the organ can be infused with an electrolytic solution. In the case of the lung, for example, an electrolytic solution may be administered through an airway tract into the inner vestiges and cavities of the lung. An electrode catheter may then be fed into the lung via the same or different airway tract and the entire organ immersed into the electroporation tank previously filled with electrolyte. Either the electrolytic solution inside the organ, or the solution in the tank may contain the molecule(s) to be administered to the cells of the organ. By connecting both the electroporation tank and the electrode catheter to a pulse generator, a pulsing regime may be employed that would cause electroporation of both inner and outer surfaces of the organ.

(f) Implantable electrodes

Implantable electrodes also may be used to electroporate the lung in vivo. These types of electrodes are routinely used in cardiothoracic surgery and can be easily inserted into the pleural space between the lung and the chest wall. The implantable electrodes can be used in conjunction with an electrode catheter fed into the lung or other type of non-penetrating electrode to deliver a pulsing protocol programmed into a pulse generator.

(g) Electrode bag or mesh The inventive method also envisions an electroconductive "bag" or "mesh" that is used to deliver an electrical field across a wide surface area of tissue. The conductive material may comprise a conductive, but inert metal such as platinum, gold or silver. The material may be wrapped around the entire organ, or a part thereof, and when connected to a pulse generator it would create an electrical field that would propagate across a wide surface area of the organ.

Thus, the skilled artisan may use a combination of external and internal electrode devices, which may be connected to the same or different pulse generators, to deliver an electric pulse to an organ of choice. Furthermore, the skilled artisan may perfuse an electrolytic administering solution or gel via a catheter, endoscope, or laparoscope throughout an organ's inner cavities and vessels to help conduct the electrical field to remote areas of the organ. Thus, an electrode need not necessarily be in direct contact with a surface of the organ. That is, an electrode catheter may rest within an electrolytic solution delivered into the lumen of an organ's internalized vessels, such that an exposed tip of the electrode does not touch any internal surface of the lumen. Likewise such an electrolytic fluid or gel may be administered such that it coats the surface of the organ. Nevertheless, because the electrode tip is surrounded by an electrolytic administering solution, an electrical field would still be propagated through the electrolyte and into the cells of the surrounding tissue, even though the electrode tip itself is not in direct contact with that tissue surface. Such methods and devices may be used to administer electrical fields to organs either in intact animals or to extracorporeal organs. In the case of organs treated outside of the body, the organ may be placed in a container or "bath" of a conductive solution in continuity with an electrode of one polarity, and a second electrolyte solution or gel may be instilled into epithelial or endothelial-lined channels of the organ and placed in electrical continuity with an electrode of opposite polarity. It is preferred that such electrodes are manufactured of a relatively inert conductor such as platinum, gold, or other inert conducting material. In this example, the tissue between the two electrolytes may be subjected to electrical pulses carried by the two fluids or gels when electrical pulses are administered to the two electrodes of opposite polarity that are in continuity with the corresponding electrolytes.

In the case of preparing a lung for administering and electroporating, one may administer a "cleansing solution" through a tube fed through the trachea, such as bronchoscope or an intubation tube, to pretreat the lung in order to remove obstructing matter. The cleansing solution may comprise co-factors such as mucolytic agents such as n-acetyl cysteine or DNase to rid the lung of mucus which may obstruct electroporation and gene/drug delivery to the lungs of cystic fibrosis patients. Other organs may be similarly pretreated to flush out obstructions or to add cofactors that may enhance the inventive method and the introduction of a molecule of interest across a cell membrane.

In any event, one of the two mainstem bronchi leading to each lung may be occluded, so as to prevent solution from being delivered to that lung. For instance, when dealing with procedures that involve the lung, one typically treats one lung while ventilating the other. In that case, the intubation device, such as a flexible tube, which is used to deliver the cleansing or administering solution to, for instance, the right lung, may further comprise a second tube that serves to ventilate the left lung. The right lung may be treated with cleansing and administering solutions delivered via the or through one of any types of suitable catheters. The left and right lungs may be accessed by separate devices, or by the same device that is modified to channel fluid into one lung while ventilating the other. As described above, the administering solution is delivered in a similar fashion to the same lung. In a similar fashion, the administering solution may be rinsed after treatment, and a solution containing beneficial co-factors such as described above (see: the administering solution) may be administered to the organ for a variable period of time. A catheter electrode, such as one of any described above, is inserted through the intubation tubing used to deliver the administering solution and is directed into the pretreated lung. A cardioversion paddle may then be used in conjunction with the internalized electrode to generate an electrical field between the catheter electrode and the cardioversion paddle and to deliver a pulse or number of pulses to the chest cavity, specifically the lung.

Alternatively, no electrode catheter may be fed into the lung, but only electrolytic administering solution. When the cardioversion paddles are placed on the chest and an electrical field generated by pulsing, the electrical field will be propagated through the electroyte. However, instead of using cardioversion paddles, an incision could be made in the individual's chest such that an electrode is fed into the pleural space of the lung and then pulsed in conjunction with the internalized electrode catheter. Alternatively, the individual's lung, or a part thereof, is surgically exposed and an electrode applied to the lung's outer surface. After such treatment, the lung tissue is replaced into the thoracic space from whence it was obtained, and the thoracotomy is closed in a fashion familiar by one skilled in the art of thoracic surgery. Those skilled in the art realize that it is necessary to avoid inducing a pneumothorax condition and so the artisan must remove air within the pleural space using a chest tube and applying gentle negative pressure. A variation on this procedure includes the gentle application of sufficient air pressure through the endotracheal tube after replacing the lung in the thorax such that the treated lung is inflated prior to wound closure. This particular procedure reduces the atelectasis (lung collapse), otherwise associated with the procedure.

Results obtained via this latter approach indicate that electroporation of the lung, after instilling a plasmid through the bronchial airway, causes near a 1 00-fold increase in transfection activity of DNA into lung cells, compared to when electroporation is not used. Moreover, transfection activity is doubled when ATA, a nuclease inhibitor, is present in the administering solution, along with the plasmid DNA, in conjunction with electroporation (see Table 1 ).

Table 1 : Effect of electroporation and nuclease inhibitor on transfection activity of plasmid DNA in the lung

* p = 0.008, * * p = 0.047 compared to rats that received electroporation and ATA (0.5 mg/kg)

The inventive method also can be used to deliver a molecule of interest to an organ destined for transplantation. One skilled in the art may insert an electrode catheter inside the organ and place another on the organ surface and then employ an electroporation pulsing regime. The internal catheter may comprise an electrode and the electrode on the external surface of the organ could be a conductive bag or mesh, a penetrating or non-penetrating electrode, an electroporation tank, a patch electrode or a set of cardioversion paddles, for example. Thus, electroporating would deliver a plurality of electrical pulses to both the internal and external surfaces of the organ.

In this regard, an organ obtained for transplantation purposes may be stored in a preserving solution as one skilled in the art would routinely do in preparing the organ for transplantation. The organ could then be removed from such a preserving bath and treated by washing throughout with a cleansing solution, similar to the one described above, by administering the cleansing solution through a lumen attached to the organ. This serves to flush out residual preserving solution as well as any bodily fluids still inside organ cavities or vessels. The administering solution may then be administered to the organ through the same lumen using a catheter device. In this case, the administering solution may comprise immunomodulatory agents to prime the lung prior to transplantation and to reduce immunological graft rejection by the recipient. The catheter may already comprise electrodes or the catheter used to deliver the administering solution may be withdrawn and an electrode catheter may be fed into the organ through the same or different lumen attached to the organ. Another electrode, such as a penetrating electrode, caliper electrode or patch electrode, for example, may then be applied to the surface of the organ such that an electrical field would be generated between the internal and surface electrodes. Alternatively, the organ may be placed within an electroconductive "bag" or mesh, as described above. The bag may be used to apply an electrical field to a large surface area of the organ. Similarly, if an electrode is inserted, by catheter, for example, into an internal region of the organ, in conjunction with the electroconductive bag or mesh, the electrical field would be established between the external and internal areas of the organ. Thus, the electric field would propagate throughout a certain section of the organ and thus cause the poration of many cells. Similarly, if the administering solution comprised electrolytes, the pulses of electricity could be propagated throughout even further vestiges of the organ. On the other hand, once the organ has been flushed with a cleansing solution and the administering solution has been administered to the organ through an attached lumen, the organ may be electroporated by placing two electrodes directly on the organ's surface. Similarly, a combination of non-penetrating, penetrating or patch electrodes may be used to deliver an electrical pulse to the organ. The administering solution comprising the molecule of interest may be administered through the surface of the organ by either rubbing the surface with an ectopic preparation of the administering solution or by bathing the organ in the administering solution, prior to applying the electrical field and pulses.

The organ may be placed in an electroporation tank containing an electrolyte, as described above, and electroporated by a pair of electrodes placed on the organ surface or by an electrode placed inside the organ in conjunction with an electrode placed on the organ surface. A mammal's organ that is destined for xenotransplantation into a human, also may be transformed according to the instant invention. That is, according to the methods described herein, a molecule of interest may be administered to an organ of a mammal and the organ then electroporated and prepared for transplantation. The molecule of interest could be any one of the molecules described herein. A mammal is a pig or a nonhuman primate. Additionally, an organ from any nonhuman animal may be transformed according to the inventive method. The applicants also envision using the inventive method to deliver a molecule of interest to a fetus in utero with ultrasound guidance via transaminotic tissue injection. The molecule may be administered in order to induce immunogenic tolerance in a fetus for example. The molecule can administered by any one of the delivery and electroporative mechanisms described herein, such as by catheter, into the amniotic cavity surrounding the fetus. For instance, the vascular supply of the placenta may be canulated to provide transplacental delivery of a molecule of interest in an administering solution. The aminotic fluid may be directly injected with the molecule of interest or, alternatively, one of skill in the art would know how to cathertize the umbilical vein of the fetus in order to introduce the molecule of interest directly to the fetus. Ultrasound can be used to guide the delivery of a molecule via intraperitoneal or intrahepatic routes known to those of skill in the art. See, for instance, Tarantal et al. (2001 ).

Similarly, electrode catheters may be introduced through the umbilicus to apply pulse regimes, such as those described herein. Alternatively, electrodes may be placed on the skin of the abdomen of the mother to deliver a pulsing regime. Alternatively, electrodes can be placed on the uterine walls using laproscopic methods known to the skilled artisan. Essentially any type of transamniotic placement known to those of skill in the art may be used place electrodes directly in amniotic fluid. An electrical "pulse" is typically characterized by a specific field strength, frequency and duration. In the instant invention, lung tissue is electroporated with from about 4 pulses to about 8 pulses, wherein each pulse comprises a field strength of between 200-500 V/cm; a frequency of 1 Hz; and a duration of between from about 10 ms to about 20 ms. These parameters create pores in lung cells but do not damage the lung tissue. The frequency and the duration may be varied so long as the voltage applied to the tissue is from about 200 V/cm to about 500 V/cm. It should be noted, however, that greater voltages may be applied to a tissue if the administering solution comprises factors that may improve the tissue's ability to withstand the greater voltage. For example, the administering solution may specifically comprise cofactors which aid wound healing or aid in the treatment of electrically-induced tissue trauma. Preferably, each pulse is 300 V/cm, the duration is 10 ms and the frequency is 1 Hz. Preferably, 4 pulses of 300 V/cm, 10 ms duration and 1 Hz are delivered to an organ.

In addition to the method and applications, the instant invention also is directed to a kit that includes devices and solutions necessary to practice the invention. Such a kit includes, but is not limited to, at least one pair of electrodes, one or more electrical pulse generator(s), an administering solution, and pulsing protocols. WORKING EXAMPLE

Plasmids

A protein-encoding polynucleotide was inserted into a plasmid such that it was operably linked to a cytomegalovirus immediate early promoter/enhancer that would drive its expression. Two such CMV promoter-driven plasmids were made and administered according to the inventive method. Specifically, plasmid pCLuc was made to encode the P, pyralis luciferase polynucleotide and pEGFP-N1 designed to encode the A, Victoria green flurorescent protein (GFP) polynucleotide. The plasmids were grown in E.coli XL-1 blue cells, isolated by the alkaline lysis method and endotoxin-purified using anion exchange chromatography (Qiagen, Zurich, Switzerland). The quality and quantity of purified plasmid DNA was assessed by absorption measurements at 260 nm and 280 nm as well as electrophoresis on a 1 w/v % agarose gel. 500 μg of pCLuc plasmid was diluted to 500 μl with 5% glucose before use; 2.5 mg of the pEGFP-N 1 plasmid was diluted to 500 μl in 5% glucose before use. The use of aurintricarboxylic acid

A triammonium salt of aurintricarboxylic acid (#A-0885, Sigma, St. Louis, MO) was prepared as a 1 mg/ml solution in sterile water for injection. The salt was filtered through a 0.2 micron cellulose acetate filter (#1 90- 2520, Nalgene, Rochester, NY). For electroporation with [plasmid 4- ATA] treatments, the ATA solution was added to the plasmid solution and administered to animals at a dose of 0.5 μg per gram of animal weight. Intubation and administration of plasmid DNA into the lung Inbred male F344 rats (weighing 1 60-260 g) were maintained on ad libitum rodent feed and water in a temperature-controlled room prior to being anesthetized and intubated for purposes of the present invention. Rats were anesthetized by halothane inhalation in a chamber. The animal then was withdrawn from the chamber and intubated with a 1 4-gauge catheter endotracheal tube placed into the trachea and affixed by suture to the incisors. The endotracheal tube was then attached to a mechanical ventilator with 1 cm water positive pressure and ventilated with halothane in room air supplemented with oxygen. After an appropriate period to recover full anesthesia, a left lateral thoracotomy was performed with clamshell retractor placement. The endotracheal tube was removed from the ventilator, and 500μl of plasmid solution, with or without ATA, was instilled via the endotracheal tube followed by a 1 ml air bolus. In larger animals, the agent may be administered using a wide range of methods including bronchoscopic administration. The animal was returned to mechanical ventilation for five minutes to facilitate distribution of the plasmid solution. The rat was placed in the right later position, moistened cotton swabs were used to gently lift the left lower lobe out of the thorax while avoiding torsion or stress on the lung hilar structures. Electroporation of the lung

The two faces of a caliper electrode were placed so that the cathode was on one side of the visceral lung pleura, with the anode covering a swath of the corresponding opposite pleura. Electrode surfaces in contact with lung tissue measured 1 .5 by 1 cm. The proximal and distal aspect of each electrode was wrapped with a 1 mm band of electrical insulating tape. The retracted lung tissue was clamped between the two electrodes. A Genetronics/BTX ECM 830 (Genetronics Biomedical, San Diego, CA) was then used to administer trains of unipolar square wave electrical pulses as described for the individual experiments. Specifically, it has been determined that eight electrical pulses with field strengths ranging from 200V/cm to 500 V/cm of 20 ms duration and one Hz frequency may be used for this purpose.

In particular, we discovered that pulsing lung tissue with eight pulses of 300V/cm field strength, each 20 milliseconds in duration, at a frequency of one Hz, provides for transfection of lung tissue while preserving lung function as measured by functional gas exchange using the arterial blood gas test.

Replacement of lung

After treatment, the lung was replaced into the chest cavity, and gentle positive pressure administered to re-inflate atelectatic tissue prior to two layer thoracotomy closure. Pneumothorax was avoided by removing air within the pleural space using a chest tube and gentle negative pressure. After closure, the animal was ventilated with oxygen lacking halothane, the endotracheal tube removed, and allowed to recover from treatment and surgery for approximately twenty four hours, during which time transgene expression from the transfected plasmid occurred. Assessment of functional status of the lung

Analyses of blood gas was performed to assess the functional status of the lung after treatment with various electrical pulsing protocols. Immediately prior to sacrifice, rats were re-intubated via tracheotomy and ventilated with 1 00% O₂ at a positive end expiratory pressure of 5 mm H₂O, a frequency of 100/minute and a tidal volume of 8 ml/kg. For functional assessment of the transfected left lung, the right hilum was dissected and the right pulmonary artery and right main bronchus were occluded with microvascular clips. Five minutes after occlusion, an arterial blood sample was collected from the thoracic aorta. PaO₂, in blood samples were measured on an automatic blood gas analyser (ALB500, Radiometer GmhB, Thalwil, Switzerland). Examples of resulting arterial blood gas values associated with different pulsing field strengths are summarized below in Table 2. The results demonstrate that, under these pulsing conditions, pulsing field strengths greater than 300 volts per centimeter of lung tissue were associated with significantly reduced lung function. Table 2: Effects of field strength on lung function as measured by blood oxygenation

was weighed and homogenised (Polytron, Littau, Switzerland) in 5 x ice- cold reporter lysis buffer (Promega, Zurich, Switzerland) and centrifuged at 1 4,000g for 1 5 minutes. The luciferase activity in 20 μl of lysate was measured on a luminometer, the Mediators PhL model of Mediators Diagnostika (Vienna, Austria), programmed to inject 1 00 μl of luciferase assay buffer (Promega). The specific activity of luciferase protein (QuantiLumt, Promega), determined using the PhL luminometer, was approximately 440 RLU/ng luciferase protein. Integrated light units were collected over 1 0 seconds, and all results were normalized to protein content in each sample (Biorad Dc protein assay kit, Biorad, CH) using bovine serum albumin as a standard. Data were expressed as RLU/mg protein.

Formalin fixed tissue were dehydrated through an alcohol series and xylene and embedded in paraffin. Sections with a thickness of 2 to 3 mm were cut and stained with haematoxylin and eosin, pursuant to standard procedures. Data were analyzed by unpaired Student t-test, using the Prismpad software program. All data are expressed as the mean + SEM. Results were considered significant if p was less than 0.05. Table 3: Arterial gas analysis and extent of transfection activity

Further experiments involved lung transplantation. Plasmid (luc)/ATA (Aurintricarboxylic acid) mixture was instilled intratracheally and electroporation was performed in the F344 rat donor. Unilateral left syngeneic lung transplantation was performed. Treated animal groups (CMV and Ubiquitin, n = 4 each) were sacrificed after 1 0,20, and 40 days. Luciferase and eGFP expression was imaged and measured. Bronchoalveolar lavage (BAL), histology, and gas exchange of the grafts were measured. Inbred male F344 rats (230 - 280g) were maintained ad libidum on rodent feed and water in a temperature-controlled room. All animals were maintained and experimentation performed in compliance with the standards of the European Convention of Animal Care. The study protocols were approved by the University of Bern Animal Study Committee (protocol #1 03/99).

Native lung fluid instillation and electroporation.

We anaesthetized the Fischer F344 rat by inhalation of 4% Halothane in a glass chamber, intubated with a 1 4 GA IV. catheter (Insytea, Madrid, Spain) and maintained the anesthesia with 2% Halothane and FiO2 = 0.5 Oxygen, f = 100 /min, TV = 10 ml/kg, PEEP = 5 mm H20 by Harvard Rodent Ventilator model 683 (Harvard Apparatus, MA, USA). The left thoracotomy in the 4th intercostal space was performed. The animal was placed on the left side, head higher than the trunk. The 0.3 ml saline consisting of 250ug of DNA and 200ug of ATA (Aurintricarboxylic acid) was injected through the intubation tube using 1 ml Luer syringe. The rest volume of the syringe was filled with air. Two additional 1 ml fast air injections followed for better fluid dispersion in the animal bronchial tree. After 5 min the animal was placed on the right side, the left thoracotomy expanded, and the pulmonal ligament was removed using two little 0.9% NaCI moistened cotton-swabs. The hilum was prepared and cleaned of the fat. Then the left lung was mobilized on the hilum through the thoracotomy wound outside the pleural cavity using rolling movements of the cotton-swabs. A Parafilm sheet with a hole in it was placed around the mobilized lung for better electrical isolation. The prototypical electroporation (EP) electrode was placed around the lung, which was possibly blocked by the pressed cotton-swabs around the hilum in the end-inspiratory position in order to maintain sufficient electrical resistance. The EP followed with the optimized conditions of 4 pulses, 20ms, 300 V/cm using custom caliper electrodes. Electrodes and Parafilm were removed, and the lung replaced. Expansion of the lung was performed by 2-3 high PEEP inspirations. A chest drain (24 G x 3/4" infusion set, Terumoa, Belgium) was inserted to the left haemithorax and the thoracotomy is closed with four layers of continuous suture (4/0 Prolene). The Halothane was switched off, the thoracic drain removed and the animal was extubated after it has restored spontaneous breathing.

Donor procedure with fluid instillation and electroporation

The rat was pre-anaesthetized in a glass chamber by inhalation of 4% Halothane. Thiopental 50 mg/kg was injected intraperitoneally and the animal was put in a supine position. A tracheostomy was performed and the animal was ventilated with a 14 GA IV. catheter with FiO2 = 1 .0, f = 100 /min, TV = 1 0 ml/kg, PEEP = 5 mm H20 by Harvard Rodent Ventilator model 683. A medial thoracophrenolaparotomy was performed. The left pulmonal ligament was removed using two little 0.9% NaCI moistened cotton-swabs. A Parafilm sheet with a hole in it was placed around the mobilized left lung for better electrical isolation. The prototypical EP electrodes were placed around the lung, and cotton- swabs were pressed around the hilum in the end-inspiratory position in order to maintain sufficient electrical resistance. The EP followed with the optimized conditions of 4 pulses, 20ms, 300 V/cm using caliper electrodes. The electrodes and Parafilm were removed and the lung expended by 2-3 high PEEP inspirations. After cutting the inferior vena cava and left appendix of the heart, a small silicon hose was inserted into the main pulmonary artery via the incision in the right ventricle. Both lungs were flushed with 20 ml of LPD solution at a pressure of 20 cm H20. The trachea was then tied in end-inspiratory position. The heart- lung block was removed and the left lung was separated ex-vivo from the heart and right lung. 24 gauge cuffs were placed around the pulmonary artery and vein, these vessels everted and tied onto the cuff and fastened with 8-0 monofilament. The lung was placed in LPD sol at 10 oC until implantation.

Implantation

The recipient was anaesthetized as above. A left thoracotomy performed, as above. The pulmonal ligament was removed, and the native left lung was kept by the paper clip and mobilized out of the pleural cavity. The hilum elements were cleared and separated. The neurovascular clips were put onto the left pulmonary artery (PA) and left pulmonary vein (PV). The left main native bronchus was ligated with 6-0 polifilament thread and cut off. An incision was made in both PV and PA. The vessels were flushed with heparinized saline solution. The graft cuffs were inserted into the recipient's vessels and 6-0 polyfilament ligatures were placed around the cuffs and tied. The native PA and PV were cut off beyond the anastomosis and native lung was removed. A 9-0 Monosof, running over- and-over continuous suture was employed for bronchial anastomosis. The ventilation and then retrograde followed by anterograde perfusion of the graft were restored by removing the clips from left bronchus, PV and PA, respectively. A chest drain (24Gx3/4" infusion set) was inserted to the left haemithorax and the thoracotomy was closed with four layers of continuous suture (4/0 Prolene, J&J). The thoracic drain was removed after the animal restored spontaneous breathing and the animal was extubated.

Graft Function

On the respective days 2, 10, 20 or 40 the animal was preanaestetized as above. The animal was ventilated via tracheostomy - Harvard Rodent Ventilator model 683 with FiO2 = 1 .0, f = 100/min, TV = 1 0ml/kg, no Halothane. A thoracophreno-laparotomy in the anterior midline was performed. Microvascular clips are put on the right main bronchus and right pulmonary artery in order to ventilate and perfuse only the isolated left native or grafted lung. After establishing a steady state (5 min) 300ml of blood was aspirated from the aortic arch to a syringe for blood gas assessment (Radiometer ABL 700 Series). Subsequently the inferior vena cava and left appendix of the heart are incised and a small silicon hose was inserted into the main pulmonary artery via an incision in the right ventricle. The lungs are then flushed with 20ml of 0.9% NaCI under the pressure of 20cm H2O. The heart and lungs block was excised.

Preparation of whole and sectioned lung

Lungs were inflated and solidified using low melting agarose prior to microdissection and/or analysis of levels and distribution of luciferase expression. 1 5 milliliters of a 1 % solution of low melting point agarose in 1 x PBS were heated by microwave, and then cooled to 37C. For microdissection, 1 00 microliters of 0.4% trypan blue solution was added. Anesthesia was induced in a glass chamber by inhalation of 4% halothane, and maintained with thiopental 50 mg/kg, intraperitoneal injection. A tracheostomy was performed and the animal was ventilated with a 14g IV, catheter with 1 00% Oxygen, f = 1 00/min, TV = 10ml/kg via a Harvard Rodent Ventilator model 683. Thoracic contents were accessed via median stemotomy, the inferior vena cava and left appendix of the heart was cut, and a small silicon hose was inserted into the main pulmonary artery via an incision in the right ventricle. The endotracheal tube was secured with suture, both lungs were flushed with 20ml of 0.9 normal sodium chloride, and the heart/lung block with attached endotracheal tube was removed. 1 20 microliters of an 80mg/ml solution of monosodium luciferin in DPBS were added to the 37C agarose solution immediately prior to use, and this preparation was used to gently inflate the lungs via the endotracheal tube. The resulting preparation was suspended in a 4C isotonic saline bath to solidify the agarose. The inflated lung was then either warmed to room temperature and BRI imaged whole, the left lobe was microdissected and BRI imaged, or transverse sections ("breadloafing") were prepared with a cryostat knife and BRI imaged.

Bioluminescent reporter imaging (BRI)

An imaging system essentially equivalent to that described by Contag and co-workers (Neoplasia 1 999) was employed for these studies. It consisted of an intensified charge-coupled device (CCD)-camera (VIM camera, model C2400-47, Hamamatsu Photonics, Hamamatsu, Japan) fitted to a light-tight chamber (Hamamatsu Photonics) and equipped with a 50mm/f 1 .2 Nikkor lens. The images were generated on an Argus-20 image processor (Hamamatsu Photonics) and transferred via SCSI using a software module (OpenlabTM) to a computer (Macintosh G4) and processed by an image analysis software (OpenlabTM). For the detection of luciferase expression in the living rat, animals were anesthetized via 1 5 mg/kg IP Nembutal inj. Dorsal thoracic fur was removed with clippers. A 1 4g IV catheter endotracheal tube was placed orally using a nasal speculum for laryngeal visualization, and correct placement was verified by aspiration and ventilation. 60 microliters of an 80mg/ml solution of monosodium luciferin were diluted to 300 microliters in isotonic saline and instilled into the lungs via the endotracheal tube. The animal was ventilated on room air (see above) for ten minutes, the endotracheal tube removed, and BRI was performed using a dorsal exposure of the prone anesthetized animal. The bioluminescent signal was quantified by measuring the number of highlighted pixels in the area around each site of photon emission with the aid of the OpenlabTM software.

Histological analyses

After the CCD imaging the 3rd and 5th slice of the lung were put in 10% formalin solution (SIGMAa, Buchs, Switzerland) for histological analysis.

Low Melting Point Agarose with Luciferin solution

20ml of 1 % LMP Agarose in PBS solution was heated in microwave and then cooled to 37 Celsius. We added 1 20ul of D-Luciferin Monososdium Salt to the 1 5ml of agar solution. The lungs are then filled with 1 5ml of this preparation from the 20ml syringe and then quickly immersed in the ice-PBS. After 5 minutes they are placed in the room temp PBS. We obtained a greater than 1 5, 000-fold enhancement of transfection relative to naked DNA instillation, with expression throughout graft parenchyma. This expression persisted at high levels for at least 40 days. Ten days after transfection and transplantation, BAL, lung histology, and arterial blood gas values of the grafts were normal.

Claims

WHAT IS CLAIMED IS:

1 . A method of introducing a molecule of interest into a cell of an intact organ, or part thereof, comprising: (a) administering said molecule via an epithelially-lined or endothelially-lined lumen connected to said organ and (b) applying a plurality of electrical pulses to said organ, wherein said pulses are sufficient to electroporate at least some cells of said organ.

2. A method according to claim 1 , wherein said plurality of electrical pulses is generated by an electrode selected from the group consisting of caliper, needle, penetrating, non-penetrating, tweezer, paddle, catheter, electroporation tank, implantable and conductive bag electrodes.

3. A method according to claim 1 , wherein said electrical pulses are delivered through an externally exposed surface of said organ.

4. A method according to claim 1 , wherein said electrical pulses are delivered through an internal surface of said organ.

5. A method according to claim 1 , wherein said electrical pulses are delivered to between an internal surface and externally exposed surface of said organ.

6. A method according to claim 1 , wherein said organ is a lung, heart, liver, pancreas, kidney, or brain.

7. A method according to claim 1 , wherein said organ is not surgically exposed from the individual.

8. A method according to claim 1 , wherein said organ, or a part thereof, is surgically exposed.

9. A method according to claim 1 , wherein said organ, or a part thereof, is removed entirely from the individual.

10. A method according to claim 1 , wherein said molecule of interest is selected from the group consisting of a polynucleotide encoding a protein or a peptide, a drug, a therapeutic protein or a peptide, an antisense polynucleotide and a diagnostic agent.

1 1 . A method according to claim 1 0, wherein said polynucleotide encoding a protein or a peptide comprises a polynucleotide sequence selected from the group consisting of the erythropoietin gene, Factor VIII gene, elastase inhibitor gene, protease inhibitor gene, alpha-1 anti-trypsin gene, CFTR gene and a DNase gene.

1 2. A method according to claim 10, wherein said polynucleotide sequence is operably linked to at least one regulatory element present in a plasmid.

1 3. The method of claim 1 2, wherein said plasmid further comprises sequences necessary to induce homologous or non-homologous recombination events in the host genome, wherein said polynucleotide becomes integrated into the genome of a cell.

14. A method according to claim 1 0, wherein said drug is selected from the group consisting of a chemotherapeutic drug, an anti- inflammatory drug, an antitumor drug, a diuretic, a hormone and immunosuppressive drug.

1 5. A method according to claim 14 wherein said immunosuppressive drug is selected from the group consisting of azathioprine and cyclosporine.

1 6. A method according to claim 1 , wherein said molecule is selected from the group consisting of an antibiotics, sulfonamides and antiviral zidovudine.

1 7. A method according to claim 1 , wherein said molecule is a drug used to treat the heart and blood, selected from the group of consisting of antiarrhythmics, cardiotonics, vasodilators, anticoagulants and thrombolytics.

1 8. A method according to claim 1 7, wherein said cardiotonic drug is digoxin or digitoxin.

1 9. A method according to claim 1 7, wherein said vasodilator drug is selected from the group consisting of sosorbide dinitrate, nitroglycerin, calcium channel blockers and beta-blockers.

20. A method according to claim 1 7, wherein said anticoagulant is selected from the group consisting of heparin and warfarin.

21 . A method according to claim 1 7, wherein said thrombolytic drug is selected from the group consisting of plasminogen activator and streptokinase.

22. A method according to claim 1 , wherein said molecule is an antihyperlipidemic drug selected from the group consisting of lovastatin, gemfibrozil, and pravastatin.

23. A method according to claim 1 , wherein said molecule is a synthetic or recombinantly-produced therapeutic protein or peptide which facilitates transplantation, reduces acute or chronic transplant rejection, or ameliorates symptoms associated with inborn errors of metabolism or acquired disease.

24. A method according to claim 23, wherein said synthetic or recombinantly-produced therapeutic protein or peptide is selected from the group consisting of TGF-β, IL-1 0, and CTLA4-lg.

25. A method according to claim 23, wherein said synthetic or recombinantly-produced therapeutic protein or peptide is modified so it can be transported to a specific cell type.

26. A method according to claim 25, wherein said synthetic or recombinantly-produced therapeutic protein or peptide is conjugated or recombinantly fused to a cell-specific peptide signal sequence in order to direct the molecule to cells of a specific organ.

27. A method according to claim 25, wherein said synthetic or recombinantly-produced therapeutic protein or peptide is conjugated, or recombinantly fused to a polyanionic peptide, wherein said polyanionic peptide improves the water-solubility of the therapeutic protein or peptide.

28. A method according to claim 1 , wherein said molecule of interest is administered to the organ in an administering solution.

29. A method according to claim 28, wherein said administering solution is electrolytic, isotonic, hypotonic or hypertonic.

30. A method according to claim 29, wherein said administering solution further comprises a co-factor selected from the group consisting of aurintricarboxylic acid and dexamethasone.

31 . A method according to claim 28, wherein said administering solution comprises a protein which promotes wound healing, selected from the group consisting of platelet-derived growth factor, vascular endothelial growth factor, insulin-like growth factor, epidermal growth factor, basic fibroblast growth factor and endothelial derived growth supplement.

32. A method according to claim 1 further comprising the step of pretreating internal or external surfaces of said organ with a cleansing solution.

33. A cleansing solution according to claim 32, further comprising n-acetyl cysteine or DNase.

34. A method according to claim 1 , wherein said administering step is achieved by administering said molecule of interest through an epithelially-lined lumen by aerosolization, inhalation, intratracheal instillation, catherization, intraparenchymal administration, vascular perfusion, particle bombardment, topical preparations, or bronchoscopic administration.

35. A method according to claim 34, wherein the epithelially- lined lumen is an airway tract.

36. A method according to claim 1 , wherein said administering step is achieved by administering said molecule of interest through an endothelially-lined lumen by aerosolization, inhalation, intratracheal instillation, catherization, intraparenchymal administration, vascular perfusion, particle bombardment, topical preparations, and bronchoscopic administration.

37. A method according to claim 36, wherein the endothelially- lined lumen is a blood vessel or a lymphatic vessel.

38. A method according to claim 1 , wherein said electrical pulse comprises a voltage between 200-500 V/cm of variable frequency and duration.

39. A method according to claims 38, wherein said electrical pulse further comprises (a) a field strength between 200-500 V/cm, (b) a frequency of 1 Hz, and a (c) a duration of 20 ms.

40. A method of preparing an organ or part thereof, for transplantation, comprising: obtaining an organ; treating the organ with a cleansing solution administered through a lumen connected to the organ; perfusing the organ with an administering solution comprising an immunomodulatory compound and electroporating the organ, wherein said cleansing step washes internal regions of the organ and wherein said electroporating step is performed by delivering a plurality of electrical pulses to the internal and external surfaces of said organ.

41 . A method according to claim 1 , wherein the intact organ is a nonhuman organ destined for xenotransplantation.

42. A method according to claim 1 , wherein a molecule of interest is delivered in utero.