WO2015038065A1 - Plasma microvesicle biomarkers for ischemic stroke - Google Patents

Plasma microvesicle biomarkers for ischemic stroke Download PDF

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WO2015038065A1
WO2015038065A1 PCT/SG2014/000422 SG2014000422W WO2015038065A1 WO 2015038065 A1 WO2015038065 A1 WO 2015038065A1 SG 2014000422 W SG2014000422 W SG 2014000422W WO 2015038065 A1 WO2015038065 A1 WO 2015038065A1
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ischemic stroke
patients
seq
biomarker
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PCT/SG2014/000422
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French (fr)
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Siu Kwan Sze
Christopher Chen
Arnab DATTA
Palau Xavier Ramon GALLART
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Nanyang Technological University
National University Of Singapore
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Publication of WO2015038065A1 publication Critical patent/WO2015038065A1/en

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/48Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/50Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
    • G01N33/68Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids
    • G01N33/6893Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids related to diseases not provided for elsewhere
    • G01N33/6896Neurological disorders, e.g. Alzheimer's disease
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2800/00Detection or diagnosis of diseases
    • G01N2800/28Neurological disorders
    • G01N2800/2871Cerebrovascular disorders, e.g. stroke, cerebral infarct, cerebral haemorrhage, transient ischemic event

Abstract

The present invention relates to the identification of plasma microvesicle biomarkers for ischemic stroke and methods and uses thereof for diagnosing ischemic stroke and/or determining the prognosis of a subject suffering from ischemic stroke.

Description

PLASMA MICRO VESICLE BIOMARKERS FOR ISCHEMIC STROKE
Field of the Invention [001] The present invention relates to the detection of plasma micro vesicle biomarkers for ischemic stroke and methods and uses thereof for diagnosing ischemic stroke and/or determining the prognosis of a subject suffering from ischemic stroke.
Background of the Invention
[002] Stroke is one of the major causes of mortality, morbidity and disability.
Stroke is a manifestation of vascular injury to the brain and responsible for more than 20% of all deaths worldwide (Lopez, A. D.; et al. Lancet 2006, 367, (9524), 1747- 1757). In Singapore, stroke is a major cause of mortality and morbidity which accounts for more than 29% of the total years of life lost (Phua, H. P.; et al. Singapore Med J 2009, 50, (5), 468-78.). Stroke can be categorized into two broad types, "ischemic stroke" and "hemorrhagic stroke." Ischemic stroke encompasses thrombotic, embolic, lacunar and hypoperfusion types of strokes. Thrombolysis remains the only effective treatment strategy for acute ischemic stroke (Donnan, G. A.; et al. Nature Reviews Neurology 201 1, 7, (7), 400-409).
[003] Lacunar infarction (LACI) is a subtype of ischemic stroke that accounts for approximately a quarter of all ischemic stroke cases (Wardlaw, J. M., Future Neurology 2011, 6 (2), 201-221). Inadequacies of the imaging tools to reliably examine small cerebral arteries and arterioles cause potential misclassification of this ischemic stroke subtype for diagnosis, treatment and prognostication. Current stroke guidelines do not differentiate between lacunar and nonlacunar strokes (e.g. large vessel stroke or cardioembolic) with respect to treatment, risk factor modification or long-term outcome (Rajapakse, A.et al. Stroke 2011, 42 (1), 217-220). Similarly, many of the major secondary stroke prevention trials have not distinguished between the different types of ischemic stroke, which may be important in determining the differential protective influence of various therapeutic approaches (e.g., antiplatelet drugs or thrombolysis) (Kirshner, H. S. J. Neurol 2010, 257 (11), 1788-1797). However, mounting evidence suggests differences in LACI pathology by comparison with non-lacunar strokes. Nevertheless, LACI remains a poorly understood area in terms of its etiology, pathophysiology, and more importantly, prognosis (De Silva, D. A.; et al. Journal of the Neurological Sciences 2007, 260 (1-2), 147-9.).
[004] Unlike non-lacunar subtypes of ischemic stroke, the short-term prognosis of ischemic cerebral small-vessel disease (SVD), including LACI is more favorable with an almost negligible early mortality, an absence of neuropsychological impairment and an excellent neurological recovery. However, LACI causes an increase in the mid- or long-term risk of recurrent vascular events and cognitive impairment or neuropsychological abnormalities. It has been shown recently that the proportion of dementia caused by SVD ranges from 36 to 67% (Grau-Olivares, M; Arboix, A., Expert Review of Neurotherapeutics 2009, 9 (8), 1201-1217). Therefore, apart from early diagnosis of LACI, identifying the patient cohorts that are at mid- or long-term risk for recurrent vascular events or complications, such as vascular dementia or neuropsychological abnormalities, will individualize and improve the treatment and recovery paradigms.
[005] Blood-based biomarkers can serve as an alternative tool to complement and improve the prognostic ability of clinical features and neuroimaging. Biomarkers for prognosis of ischemic stroke are a relatively new concept compared to other therapeutic areas such as cancer. No single or panel of blood-based biomarkers has been validated by clinical trials for stroke or related secondary complications. Therefore, CSF (Zimmermann-Ivol, C. G. et al. Mol. Cell. Proteomics 2004, 3 (1), 66- 72) or brain extracellular fluid (Giron, P.; et al. Journal of Proteome Research 2011, 10 (1), 249-258) have been used as starting materials for biomarker discovery in stroke.. Such biological samples are however painful and difficult to extract because of the extremely invasive nature of the methods used. To solve this several studies had been performed to validate protein biomarkers from blood (Foerch, C; et al. Neurology 2009, 73 (5), 393-9.), but only a few of these studies were directed specifically to SVD (Elkind, M. S. V.; et al. International Journal of Stroke 2010, 5 (2), 1 17-125). In addition, most have tried to validate one or a few candidates (Bettermann, K., J Stroke Cerebrovasc Dis 2011, 20 (3), 173-6.).
[006] Brain-specific Myelin basic protein (MBP) has been detected in the systemic circulation in nanogram concentration during the acute phase (e.g. hrs to few days) of ischemic stroke and is correlated with acute (24 hrs) or subacute (3 months) outcomes using targeted assays (Hill, M. D.; et al. CMAJ 2000, 162 (8), 1 139-40). Generally, any circulatory biomarkers present in the brain that may be associated with neurological disorders would not be found in plasma as brain parenchyma remains selectively accessible by the systemic circulation due to the presence of blood brain barrier (BBB) under physiological conditions. However, different cell types in the brain (e.g. microglia and oligodendrocytes) are reported to release substances to the neighboring cells and external environment. A fraction of these substances may drain into the cerebrospinal fluid (CSF) and eventually in the blood. BBB abnormality is generally more diffuse in small vessel stroke compared to non-lacunar stroke subtypes that may cause gradual and sustained leakage of brain-specific MBP into general circulation (Wardlaw, J. M.; et al. Stroke 2003, 34 (3), 806-12.). Chronic hypoperfusion of the white matter leading to progressive and selective death of oligodendrocytes by apoptosis and subsequent degeneration of myelinated fibres have been demonstrated in animals and in autopsized human brain of small vessel disease (Pantoni, L., The Lancet Neurology 2010, 9 (7), 689-701).
[007] Using whole blood plasma limited the detection sensitivity for low abundant proteins. The proteomic approach for biomarker discovery from crude plasma is technically limited by its complexity and extreme dynamic range (>1010), thereby resulting in poor sensitivity for detecting low abundant plasma proteins (Anderson, L.; Hunter, C. L., Mol. Cell. Proteomics 2006, 5 (4), 573-588). To overcome this challenge, multiple approaches have been described that includes biophysical fractionation, enrichment of target sub-proteome and immuno-depletion of the most abundant interfering proteins. However, none of them were able to significantly outclass the other techniques (Whiteaker, J. R.; et al. Journal of Proteome Research 2007, 6 (2), 828-836.).
[008] In view of the above, LACI remains a poorly understood area among acute ischemic stroke whose etiology, pathophysiology, and more importantly, the diagnosis and treatment largely remains in the shadow of non-lacunar subtypes despite it has relatively higher prevalence among Asian populations. Lack of well- defined diagnostic strategies and risk-factor based classifications are some of the major reasons for the above-mentioned shortcomings. Routinely used brain imaging techniques are often not sufficient to produce high resolution images for patients with LACI affecting small arterioles (0.2 - 0.8 mm) and having smaller sized infarcts than the larger territorial infarct seen in non-lacunar strokes. Neuroimaging techniques usually have low sensitivity to detect small infarcts in certain locations (posterior fossa, cortex) and during the acute stage cannot differentiate between acute and old lesions. The diagnostic dilemma causes misclassification of approximately 20% of lacunar stroke as cortical stroke or vice-versa. In addition, there are situations where MRI is contraindicated, such as in medically unstable patients or those with an MRI- incompatible implanted device, body metal, or severe claustrophobia. Hence, an unmet need exists to complement and improve the effectiveness of the existing symptomatic and diagnostic protocols in the acute setting.
Summary of the Invention
[009] The present invention is based on the inventors' surprising finding that plasma microvesicles comprise biomarkers that are useful in the diagnosis of ischemic stroke and related conditions as well as determining the prognosis of stroke patients.
[0010] Microvesicles are membrane-bound vesicles, ranging in size from 0.04-1 μηι. They are reported to be involved in the pathogenesis of various diseases such as ischemic stroke (Horstman, L. L.; et al. Neurological Research 2009, 31 (8), 799- 806), thrombosis, diabetes, inflammation, atherosclerosis and vascular cell proliferation (Azevedo, L. C. P.; et al. Recent Patents on Cardiovascular Drug Discovery 2007, 2 (1), 41-51). Microvesicles can be secreted from endothelial, circulatory (e.g. platelets, leukocytes, erythrocytes), and even central nervous system (CNS)-specific cell types (e.g. microglia and oligodendrocytes) (Mathivanan, S.; Ji, H.; Simpson, R. J., Journal of Proteomics 2010, 73 (10), 1907-20.).
[001 1] Accordingly, a first aspect of the invention relates to a method for determining the prognosis of a subject afflicted by ischemic stroke comprising: a) isolating plasma microvesicles from a plasma sample obtained from the subject; and b) determining the presence and/or amount of at least one biomarker associated with the isolated plasma microvesicles; c) comparing the determined presence and/or amount of said at least one biomarker with a control, wherein a change in the presence and/or amount of the at least one biomarker relative to said control is indicative for said subject having an unfavorable prognosis.
[0012] A further aspect of the invention relates to a method for predicting the risk of a subject developing ischemic stroke, comprising: a) isolating plasma microvesicles from a plasma sample obtained from the subject; and b) determining the presence and/or amount of at least one biomarker associated with the isolated plasma microvesicles; c) comparing the determined presence and/or amount of said at least one biomarker with a control, wherein a change in the presence and/or amount of the at least one biomarker relative to said control is indicative for an increased risk of said subject developing ischemic stroke.
[0013] A still further aspect of the invention relates to a method for diagnosing ischemic stroke in a subject comprising: a) isolating plasma microvesicles from a plasma sample obtained from the subject; and b) determining the presence and/or amount of at least one biomarker associated with the isolated plasma microvesicles; c) comparing the determined presence and/or amount of said at least one biomarker with a control, wherein a change in the presence and/or amount of the at least one biomarker relative to said control is indicative for said subject having suffered an ischemic stroke.
[0014] Another aspect of the invention relates to a panel of biomarkers for determining the prognosis of a subject afflicted by ischemic stroke, predicting the risk of a subject developing ischemic stroke or diagnosing ischemic stroke in a subject, wherein the panel comprises at least one, preferably at least two, more preferably at least 5 markers selected from the group consisting of polypeptides set forth in SEQ ID NOS 1-1 14.
[0015] In another aspect, the invention relates to use of the panel of biomarkers disclosed herein for determining the prognosis of a subject afflicted by ischemic stroke, predicting the risk of a subject developing ischemic stroke or diagnosing ischemic stroke in a subject.
[0016] Other aspects of the invention will be apparent to a person skilled in the art with reference to the following drawings and description of various non-limiting embodiments.
Brief Description of the Drawings [0017] The drawings are not necessarily drawn to scale, emphasis instead generally being placed upon illustrating the principles of various embodiments. In the following description, various embodiments of the invention are described with reference to the following drawings.
[0018] Figure 1. Schematic representation of the experimental design. ERLIC, electrostatic repulsion hydrophilic interaction chromatography.
[0019] Figure 2. Demographic Characteristics of the Patient Population
Stratified by the Outcome Measures.
[0020] Figure 3. Pictures of a representative microvesicle pellet against different backgrounds. The loose hollow at the bottom of the tubes (shown by arrow) was obtained by sequential normal (4000g, 12000g) and ultra-centrifugation (30000g and 200000g) of plasma.
[0021] Figure 4. The List of Qualified and Regulated Plasma Microvesicle Proteome. The list contains quantitative information of the selected proteins from bias and background corrected iTRAQ data set. The denominator is the demographically matched control. Unused and % coverage are parameters related to the confident identification of proteins. This list contains 43 candidates qualified (out of 183) through the initial filters [i.e., unused prot score >3.0 and FDR = 1.1% (confident identification), p-value <0.05 (significantly different from 1) for at least two ratios]. The significant ratios are indicated in bold. The Uniport accession numbers of the 'unreviewed' proteins are indicated in italics form. The protein whose evidence is available only at the level of transcript is not provided with a gene symbol. The last column provides information about GO or pathway. CCC = complement and coagulation cascade, ECS = extracellular space, EIA = enzyme inhibitor activity, FA = focal adhesion, IIR = innate immune response, LT= lipid transport, RTW = response to wounding.
[0022] Figure 5. A List of the five most significant up-regulated biomarkers in plasma microvesicles of LACI patient with adverse outcome, and B List of the five most significant down-regulated biomarkers in plasma microvesicles of LACI patient with adverse outcome.
[0023] Figure 6. List of unique up-regulated biomarkers in plasma
microvesicles of LACI patient with adverse outcome.
[0024] Figure 7. List of unique down-regulated biomarkers in plasma microvesicles of LACI patient with adverse outcome.
[0025] Figure 8. A Histogram showing the iTRAQ ratios of selected proteins related to focal adhesion (ITGA2B, TLNl and FLNA) and coagulation cascade (FGA, FGB and PLG). Demographically matched control group was used as the common denominator (i.e. 114) for comparing the three groups of LACI patients. The solid line indicates no change in regulation. The LACI groups with adverse outcome (recurrent vascular event, 1 16; cognitive decline, 117) had a differential signature in comparison with the LACI group with no adverse outcome (i.e. 1 15). Up-regulation of proteins related to focal adhesion and coagulation (FGA, FGB) is predictive of poor outcome. * Denotes ratios with significant p-value (< 0.05). B Technical validation of iTRAQ result by Western Blot analysis of ALB on pooled lysates. ALB showed downward trend in LACI - recurrent vascular event group unlike the LACI group with no adverse outcome, which is consistent with the iTRAQ result.
[0026] Figure 9. Synopsis of the in vivo study to capture the interplay of multiple events in the ischemic brain by iTRAQ-MuDPIT approach.
[0027] Figure 10. Schematic diagram showing the 4-plex iTRAQ-MuDPIT guided biomarker discovery approach.
[0028] Figure 11. Schematic diagram showing the experimental design.
Shortlisted candidates from the discovery phase will be validated by duel strategy of multiplex validation involving Luminex and MRM assay. Fifty patients with LDV (large vessel disease) will be included in two phases to check the specificity of the candidate biomarkers. **Number of LACI patients in different sub-groups is variable.
[0029] Figure 12. A Western blot of MBP in control samples and samples taken from LACI patents that exhibit recurrent vascular events and B densitometry results of the western blots.
[0030] Figure 13. A MS/MS quantification of MBP from microvesicles isolated from 500μ1 of plasma using a combination of a sucrose gradient and
ultracentrifugation, and B the western blot quantification of MBP from microvesicles isolated from 500μ1 of plasma using a combination of a sucrose gradient and ultracentrifugation.
[0031 ] Figure 14. Western blot quantification of MBP from microvesicles isolated from 1 ΟΟμΙ of plasma using soluble protein precipitation for micro vesicle purification method.
[0032] Figure 15. Bar graph showing the number of times that each LACI biomarker has been identified in the plasma exosomal fraction of individual subjects (healthy control and LACI patients including recurrent vascular events and cognitive decline) by LC-MS/MS. The isolation of the exosomal fraction was done following the "soluble protein precipitation for microvesicle purification method" described in the example 20.
Detailed Description
[0033] Considering the research gaps stated in the background section above, blood-based biomarkers were developed as an alternative tool to complement and improve the effectiveness of the existing protocols relying on clinical features and neuroimaging. By predicting LACI patients who are at risk of recurrent vascular events or cognitive decline, these biomarkers can guide clinicians to stratify patients for testing therapeutic options or rehabilitation schemes in clinical trials and practice. Conversely, these biomarkers can also be used as surrogate markers in LACI related clinical trials to monitor the consequences of therapeutic interventions. The detailed profiling of the plasma samples performed during the discovery phase and the proposed validation of a panel of proteins could also facilitate better understanding of the underlying pathology and stimulate research interest on individual biomarkers in the absence of a comparable dataset from autopsied LACI affected brain samples.
[0034] To mitigate the challenge of using whole plasma, microvesicles were isolated from plasma for stroke prognostic biomarker identification. An iTRAQ-2D- LC-MS/MS-guided shotgun proteomic strategy was applied for the discovery of potential prognostic biomarker of LACI by comparative profiling of plasma microvesicles in three groups of LACI patients and a group of demographically- matched control. Plasma samples of forty five LACI patients from the European Australasian Stroke Prevention in Reversible Ischemia Trial (ESPRIT) were used for the study (De Schryver, E. L. L. M., Cerebrovasc. Dis. 2000, 10 (2), 147-150). The patients were monitored for up to 5 yrs after index stroke for adverse outcomes (i.e. recurrent vascular events or decline in cognitive functions). Microvesicles were collected for the iTRAQ experiment.
[0035] Analysis of the significantly changed protein levels from the iTRAQ data set revealed up-regulation of a group of proteins from brain tissue in the plasma microvesicles, and proteins related to the integrin signaling (e.g. ITGA2B, TL 1, and FLNA) and coagulation cascade (FGA, FGB) that are associated with an unfavorable outcome. Given that blood collection is a simple and cheap procedure; these biomarkers can have additive value over the existing imaging, clinical or neurobehavioral modalities used in the clinic for diagnosis and prognosis of stroke, particularly for asymptomatic/silent stroke, LACI and transient ischemic attack (TIA) stroke subtypes.
[0036] Accordingly, a first aspect of the invention relates to a method for determining the prognosis of a subject afflicted by ischemic stroke comprising: a) isolating plasma microvesicles from a plasma sample obtained from the subject; and b) determining the presence and/or amount of at least one biomarker associated with the isolated plasma microvesicles; c) comparing the determined presence and/or amount of said at least one biomarker with a control, wherein a change in the presence and/or amount of the at least one biomarker relative to said control - that exceeds a given threshold value - is indicative for said subject having an unfavorable prognosis.
[0037] For purposes of the following discussion, the methods described as applicable to the prognosis of a subject afflicted by ischemic stroke generally may be considered applicable to an individual that has had an ischemic stroke including thrombotic, embolic and/or lacunar stroke and/or hypoperfusion. Preferably, the ischemic stroke is selected from the group consisting of lacunar infarction (LACI), transient ischemic attack (TIA) or silent stroke, most preferably the ischemic stroke is a lacunar infarction.
[0038] In addition, while the following embodiments are described in relation to the prognostic method of the invention, it is understood that many embodiments are equally applicable in the other methods of the invention, for example the methods of diagnosis or monitoring therapy.
[0039] The prognosis is intended to determine the potential of the individual to have an adverse outcome. An adverse outcome may include a recurrent vascular event or cognitive decline.
[0040] The term "prognosis" as used herein refers to methods by which the person skilled in the art such as a health professional can predict the course or outcome of a condition in a patient. The term "prognosis" does not refer to the ability to predict the course or outcome of a condition with 100% accuracy, or even that a given course or outcome is more likely to occur than not. Instead, the skilled health professional will understand that the term "prognosis" refers to an increased probability that a certain course or outcome will occur; that is, that a course or outcome is more likely to occur in a subject exhibiting a given indicator, when compared to those individuals not exhibiting the indicator.
[0041] The skilled professional will understand that associating a prognostic indicator with a predisposition to an adverse outcome is a statistical analysis. For example, a biomarker amount isolated from plasma microvesicles that varies from the amount of said biomarker in a control by at least 10% may indicate that the subject is more likely to suffer from an adverse outcome than patients with a level that varies less than or equal to 10%, as determined by a level of statistical significance.
[0042] Additionally, a change in marker concentration from baseline levels may be reflective of patient prognosis, and the degree of change in biomarker level may be related to the severity of adverse events. Statistical significance is often determined by comparing two or more populations, and determining a confidence interval and or a p value. Preferred confidence intervals of the invention are 90%, 95%, 97.5%, 98%, 99%, 99.5%, 99.9% and 99.99%, while preferred p values are 0.1, 0.05, 0.025, 0.02, 0.01 , 0.005, 0.001 , and 0.0001. Exemplary statistical tests for associating a prognostic indicator with a predisposition to an adverse outcome are described hereinafter.
[0043] In various embodiments, a threshold degree of change in the level of a prognostic or diagnostic indicator can be established, and the degree of change in the level of the indicator in a subject sample can simply be compared to the threshold degree of change in the level. A preferred threshold change in the level for markers of the invention is about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 50%, about 75%, about 100%, and about 150%, always in relation to a control value. The term "about" in this context refers to +/- 3%.
[0044] It should however be understood that instead of comparing a determined marker value with a control, an absolute threshold value can be determined based on previously determined control values, wherein if the determined marker amount exceeds or falls below (depending on whether up- or down-regulation of the marker is found significant) the given threshold, the change is considered relevant for prognosis.
[0045] As used herein the term "plasma microvesicles" refer to plasma membrane fragments, typically small membrane vesicles of between 0.03 and 1 micrometer (μηι) in diameter. They are formed by cells through a process of membrane budding or exocytosis. The term as used herein also includes exosomes. Exosomes are cell-derived vesicles that are smaller than about 150 nm in diameter, typically with diameters between 30 and 100 nm.
[0046] According to the described methods, the plasma microvesicles are isolated from a plasma sample.
[0047] As used herein "plasma" refers to the liquid component of whole blood that makes up approximately 55% of the total blood volume.
[0048] Generally a blood sample may be drawn from a vein and the plasma subsequently separated from the cellular blood components. However, any method of extracting blood known in the art would be similarly suitable. There are many methods known to those in the art for separating plasma from blood and any such method would be suitable for application of the present methods. The amount of blood that needs to be obtained from an individual may depend on the desired sample size and is well known to those skilled in the art.
[0049] The plasma microvesicles are typically isolated from the plasma sample by ultracentrifugation, sucrose gradient density centrifugation or soluble protein precipitation for microvesicle purification method where soluble proteins are precipitated by a suitable method such as organic solvent precipitation using acetone, methanol and acetonitrile and other suitable solvents.
[0050] The term "biomarker" as used herein refers to proteins or polypeptides to be used as targets for screening test samples obtained from the isolated plasma microvesicles of the subjects. "Proteins or polypeptides" used as biomarkers in the present invention are contemplated to include any fragments thereof, in particular, immunologically detectable fragments.
[0051] In various embodiments the biomarker is detected using a suitable detection reagent. The type of said reagent is dependent on the type of biomarker to be detected. In case the biomarker is a protein, polypeptide or peptide, the detection reagent may, for example, be an antibody or antibody-like molecule or known derivatives thereof. In various embodiments, the detection reagents may also include conjugates of the respective binding moeity, e.g. the antibody, that facilitate detection, such as biotin or fluorescent labels or artificial sequence tags. Such conjugates may be non-natural variants of the relevant binding part of the detection reagent.
[0052] "At least one", as used herein, in particular in relation to the biomarkers, may include a single one, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , 12, 13, 14, 15, 16, 17, 18, 19, 20 or more. In certain embodiments, the inventive methods employ the detection/determination of at least two biomarkers, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, at least 12, at least 14, at least 15, or at least 20 biomarkers.
[0053] The term "subject afflicted by ischemic stroke" as used herein refers to an individual that has or is suspected to have suffered an ischemic stroke within the last 6 months or less. Generally, as already mentioned above an ischemic stroke includes thrombotic, embolic and/or lacunar stroke and hypoperfusion. Preferably, the ischemic stroke is selected from the group consisting of lacunar infarction (LACI), transient ischemic attack (TIA) or silent stroke, most preferably the ischemic stroke is a lacunar infarction. The terms "lacunar stroke" and "lacunar infarction" as used interchangeably herein and relate to a type of stroke that results from occlusion of one of the penetrating arteries that provides blood to the brain's deep structures.
[0054] In various embodiments the unfavorable prognosis is an increased likelihood for an adverse event selected from the group of developing cognitive impairment, including dementia, and/or recurrent vascular events. The adverse event may also include reduced survival and death.
[0055] As used herein, the term "recurrent vascular events" may include another ischemic stroke, as defined above, in particular an ischemic event selected from lacunar infarction (LACI), transient ischemic attack (TIA) and silent stroke.
[0056] As used herein, the term "increased likelihood" relates to the increased chance of an individual to develop an adverse event compared to a control subject, e.g. a normal healthy subject or a subject that does not exhibit a significant change in one or more of the assessed biomarker levels.
[0057] In various embodiments, the prognosis is a long-term prognosis, preferably a prognosis for a time period of more than 12, more than 24, more than 36, more than 48, or more than 60 months.
[0058] A further aspect of the invention relates to a method for predicting the risk of a subject developing ischemic stroke comprising: a) isolating plasma microvesicles from a plasma sample obtained from the subject; and b) determining the presence and/or amount of at least one biomarker associated with the isolated plasma microvesicles and or exosomes; c) comparing the determined presence and/or amount of said at least one biomarker with a control, wherein a change in the presence and/or amount of the at least one biomarker relative to said control - that exceeds a given threshold value - is indicative for an increased risk of said subject developing ischemic stroke.
[0059] The term "predicting the risk of a subject developing ischemic stroke" refers to determining the likelihood that a subject that has never suffered from an ischemic stroke will suffer ischemic stroke. The ischemic stroke may be a thrombotic, embolic or lacunar stroke or hypoperfusion. Preferably, the ischemic stroke is selected from the group consisting of lacunar infarction (LACI), transient ischemic attack (TIA) or silent stroke, most preferably the ischemic stroke is a lacunar infarction.
[0060] The prediction is by a statistical determination of the statistical chance of the individual's predisposition to suffer an ischemic stroke.
[0061] A further aspect of the invention relates to a method for diagnosing ischemic stroke in a subject comprising: a) isolating plasma microvesicles from a plasma sample obtained from the subject; and b) determining the presence and/or amount of at least one biomarker associated with the isolated plasma microvesicles and or exosomes; c) comparing the determined presence and/or amount of said at least one biomarker with a control, wherein a change in the presence and/or amount of the at least one biomarker relative to said control - that exceeds a given threshold value - is indicative for said subject having suffered an ischemic stroke.
[0062] The term "diagnosing" as used herein refers to methods by which the skilled health professional can estimate and/or determine whether or not a patient is suffering from a given disease or condition. The skilled professional often makes a diagnosis on the basis of one or more diagnostic indicators, i.e., a biomarker, the presence, absence, or amount of which is indicative of the presence, severity, or absence of the condition. Ischemic stroke includes the subtypes listed above.
[0063] In various embodiments of the described methods of diagnosis or risk determination, the subject has suffered suspected or confirmed lacunar infarction.
[0064] In various embodiments of all the above-described methods, the subject is diagnosed with or already undergoing a therapy for ischemic cerebral small vessel disease (CVD).
[0065] In various embodiments, the control is a control subject, in particular a subject who has not suffered ischemic stroke or the relevant stroke subtype.
[0066] In various embodiments the plasma microvesicles include or are exosomes. The method may thus include the step of isolating the exosomes from a patient's sample.
[0067] In various embodiments the plasma microvesicles, including the exosomes, are isolated by ultracentrifugation. In various alternative embodiments, the plasma microvesicles are isolated by sucrose density gradient centrifugation. Such an isolation method has the advantage of requiring a smaller volume of plasma, for example 500μ1 or less, to obtain a sufficient amount of plasma microvesicles for biomarker analysis. In various embodiments, the plasma microvesicles are isolated by soluble protein precipitation for microvesicle purification method. Such an isolation method has the advantage of requiring an even smaller volume of plasma, such as ΙΟΟμΙ or less, to obtain a sufficient amount of plasma microvesicles for biomarker analysis. In addition, the latter method has the further advantage of allowing isolating the plasma microvesicles in about 1 hour which saves time and thus allows faster results of disease prognosis or diagnosis.
[0068] In various embodiments the amount of the at least one biomarker is determined by a combined chromatography/mass spectrometry technique, preferably LC/MS/MS technique, more preferably iTRAQ (isobaric tags for relative and absolute quantification). However, the skilled person will readily understand that in principle any proteomics methods known in the art may be similarly used.
[0069] In various embodiments the one or more biomarkers are selected from the group consisting of the polypeptides having the amino acid sequences set forth in SEQ ID Nos. 1-114.
[0070] In various embodiments the one or more biomarkers are selected from the group consisting of the polypeptides: Alpha-2-macroglobulin (A2M) that is upregulated in patients with recurrent vascular events and upregulated in patients with cognitive decline. In preferred embodiments A2M has Uniprot accession number P01023 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 1 ; Complement C3 (C3) that is downregulated in patients with recurrent vascular events and downregulated in patients with cognitive decline. In preferred embodiments C3 has Uniprot accession number P01024 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 2; Serum albumin (ALB) that is downregulated in patients with recurrent vascular events and downregulated in patients with cognitive decline. In preferred embodiments ALB has Uniprot accession number P02768 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 3; Fibrinogen alpha chain (FGA) that is upregulated in patients with recurrent vascular events and upregulated in patients with cognitive decline. In preferred embodiments FGA has Uniprot accession number P02671 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 4; Fibrinogen beta chain (FGB) that is upregulated in patients with recurrent vascular events and upregulated in patients with cognitive decline. In preferred embodiments FGB has Uniprot accession number P02675 (Version 2 ), for example having the amino acid sequence as set forth in SEQ ID NO. 5; Haptoglobin (HP) that is downregulated in patients with recurrent vascular events and downregulated in patients with cognitive decline. In preferred embodiments HP has Uniprot accession number P00738 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 6; Fibrinogen gamma chain (FGG) that is upregulated in patients with recurrent vascular events and upregulated in patients with cognitive decline. In preferred embodiments FGG has Uniprot accession number P02679 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 7; von Willebrand factor (VWF) that is upregulated in patients with recurrent vascular events and upregulated in patients with cognitive decline. In preferred embodiments VWF has Uniprot accession number P04275, (Version 4), for example having the amino acid sequence as set forth in SEQ ID NO. 8; Complement C5 (C5) that is downregulated in patients with recurrent vascular events and downregulated in patients with cognitive decline. In preferred embodiments C5 has Uniprot accession number P01031, (Version 4), for example having the amino acid sequence as set forth in SEQ ID NO. 9; IgGFc- binding protein (FCGBP) that is upregulated in patients with recurrent vascular events and upregulated in patients with cognitive decline. In preferred embodiments FCGBP has Uniprot accession number Q9Y6R7 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 10; Complement component 4 binding protein, alpha (C4BPA) that is upregulated in patients with recurrent vascular events and downregulated in patients with cognitive decline. In preferred embodiments C4BPA has Uniprot accession number Q5VVQ8 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 1 1 ; Apolipoprotein A-l (APOA1) that is downregulated in patients with recurrent vascular events and downregulated in patients with cognitive decline. In preferred embodiments APOA1 has Uniprot accession number P02647 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 12; Galectin-3 -binding protein (LGALS3BP) that is downregulated in patients with recurrent vascular events and upregulated in patients with cognitive decline. In preferred embodiments LGALS3BP has Uniprot accession number Q08380 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 13; Non-muscle myosin heavy polypeptide 9 (MYH9) that is upregulated in patients with recurrent vascular events and upregulated in patients with cognitive decline. In preferred embodiments MYH9 has Uniprot accession number Q60FE2 (Version 4), for example having the amino acid sequence as set forth in SEQ ID NO. 14; Filamin-A (FLNA) that is upregulated in patients with recurrent vascular events and upregulated in patients with cognitive decline. In preferred embodiments FLNA has Uniprot accession number P21333 (Version 4), for example having the amino acid sequence as set forth in SEQ ID NO. 15; Tailin-1 (TLN1) that is upregulated in patients with recurrent vascular events and upregulated in patients with cognitive decline. In preferred embodiments TLN1 has Uniprot accession number Q9Y490 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 16; Hemoglobin subunit alpha (HBAl) that is downregulated in patients with recurrent vascular events and downregulated in patients with cognitive decline. In preferred embodiments HBAl has Uniprot accession number P69905 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 17; CD5 antigen-like (CD5L) that is upregulated in patients with recurrent vascular events and upregulated in patients with cognitive decline. In preferred embodiments CD5L has Uniprot accession number 043866 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 18; Alpha- 1 -antitrypsin (SERPINA1) that is downregulated in patients with recurrent vascular events and downregulated in patients with cognitive decline. In preferred embodiments SERPINA1 has Uniprot accession number P01009 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 19; Plasminogen (PLG) that is downregulated in patients with recurrent vascular events and downregulated in patients with cognitive decline. In preferred embodiments PLG has Uniprot accession number P00747 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 20; Kallikrein B, plasma (Flecher factor) 1 , isoform CRA_b (KLKB1) that is downregulated in patients with recurrent vascular events and upregulated in patients with cognitive decline. In preferred embodiments KLKB1 has Uniprot accession number Q4W5C3 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 21 ; Vitamin K-dependent protein S (PROS 1) that is downregulated in patients with recurrent vascular events and downregulated in patients with cognitive decline. In preferred embodiments PROS1 has Uniprot accession number P07225 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 22; Inter-alpha (Globulin) inhibitor H4 (plasma Kalikrein- sesitive glycoprotein (ITIH4) that is downregulated in patients with recurrent vascular eventsand downregulated in patients with cognitive decline. In preferred embodiments ITIH4 has Uniprot accession number B2RMS9 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 23; Apolipoprotein LI (APOLl) that is downregulated in patients with recurrent LACI and upregulated in patients with cognitive decline. In preferred embodiments APOLl has Uniprot accession number 014791 (Version 5), for example having the amino acid sequence as set forth in SEQ ID NO. 24; Lipoprotein Lp(A) (LP A) that is upregulated in patients with recurrent LACI and upregulated in patients with cognitive decline. In preferred embodiments LP A has Uniprot accession number Q1HP67 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 25; Hemopexin (HPX) that is downregulated in patients with recurrent LACI and downregulated in patients with cognitive decline. In preferred embodiments HPX has Uniprot accession number P02790 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 26; Apilipoprotein E (APOE) that is downregulated in patients with recurrent LACI and downregulated in patients with cognitive decline. In preferred embodiments APOE has Uniprot accession number P02649 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 27; Integrin alpha-IIb (ITGA2B) that is upregulated in patients with recurrent LACI and upregulated in patients with cognitive decline. In preferred embodiments ITGA2B has Uniprot accession number P08514 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 28; Immunoglobulin J chain (IGJ) that is upregulated in patients with recurrent LACI and upregulated in patients with cognitive decline. In preferred embodiments IGJ has Uniprot accession number P01591 (Version 4), for example having the amino acid sequence as set forth in SEQ ID NO. 29; Serum paraoxonase/arylest erase 1 (PON1) that is downregulated in patients with recurrent LACI and downregulated in patients with cognitive decline. In preferred embodiments PON1 has Uniprot accession number P27169 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 30; Myelin basic protein (MBP) that is upregulated in patients with recurrent LACI and upregulated in patients with cognitive decline. In preferred embodiments MBP has Uniprot accession number P02686 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 31 ; Serine/cysteine proteiase inhibitor clade G member 1 splice variant 2 (fragment) (SERPING1) that is downregulated in patients with recurrent LACI and downregulated in patients with cognitive decline. In preferred embodiments SERPING1 has Uniprot accession number Q5UGI6 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 32; Apolipoprotein A-II (APOA2) that is downregulated in patients with recurrent LACI and upregulated in patients with cognitive decline. In preferred embodiments APOA2 has Uniprot accession number P02652 (Version 1 ), for example having the amino acid sequence as set forth in SEQ ID NO. 33; putative protein cDNA FLJ76826, highly similar to Homo sapiens ceruloplasmin (ferroxidase) (CP), mRNA that is downregulated in patients with recurrent LACI and downregulated in patients with cognitive decline. In preferred embodiments the putative protein has Uniprot accession number A8K5A4 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 34; putative protein cDNA, FLJ94213, highly similar to Homo sapiens pregnancy- zone protein (PZP), mRNA that is downregulated in patients with recurrent LACI and upregulated in patients with cognitive decline. In preferred embodiments the putative protein has Uniprot accession number B2R950 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 35; putative protein cDNA FLJ75066, highly similar to Homo sapiens complement component 1 , r subcomponent (C1R), mRNA that is downregulated in patients with recurrent LACI and downregulated in patients with cognitive decline. In preferred embodiments the putative protein has Uniprot accession number A8K5J8 -(Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 36; putative protein cDNA FLJ55673, highly similar to Complement factor B (EC 3.4.21.47) that is downregulated in patients with recurrent LACI and downregulated in patients with cognitive decline. In preferred embodiments the putative protein has Uniprot accession number B4E1Z4 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 37; putative uncharacterized protein (Fragment) that is upregulated in patients with recurrent LACI and upregulated in patients with cognitive decline. In preferred embodiments the putative protein has Uniprot accession number Q8WVW5 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 38; putative protein Thrombospondin 1 variant (Fragment) that is upregulated in patients with recurrent LACI and upregulated in patients with cognitive decline. In preferred embodiments the putative protein has Uniprot accession number Q59E99 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 39; putative protein cDNA FLJ35730 fis, clone TESTI2003131, highly similar to ALPHA- 1 -ANTICHYMOTRYP SIN that is downregulated in patients with recurrent LACI and downregulated in patients with cognitive decline. In preferred embodiments the putative protein has Uniprot accession number B3KS79 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 40; cDNA FLJ59731, highly similar to complement component C8 beta chain (C8B) that is downregulated in patients with recurrent LACI and downregulated in patients with cognitive decline. In preferred embodiments C8B has Uniprot accession number B7Z550 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 41 ; putative protein Peptidyl-prolyl cis-trans isomerase that is upregulated in patients with recurrent LACI and upregulated in patients with cognitive decline. In preferred embodiments the putative protein has Uniprot accession number A8K486 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 42; putative protein Dihydropyrimidinase-like 2 variant (Fragment) that is upregulated in patients with recurrent LACI and upregulated in patients with cognitive decline. In preferred embodiments the putative protein has Uniprot accession number Q59GB4 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 43; Cholinesterase (BCHE) that is upregulated in patients with an adverse outcome. In preferred embodiments BCHE has Uniprot accession number P06276 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 44; Diydropyrimidinase-related protein 2 (DPYSL2) that is upregulated in patients with an adverse outcome. In preferred embodiments DPYSL2 has Uniprot accession number Q 16555 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 45; Glial fibrillary acidic protein (GFAP) that is upregulated in patients with an adverse outcome. In preferred embodiments GFAP has Uniprot accession number P 14136 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 46; Dermcidin (PIF) that is upregulated in patients with an adverse outcome. In preferred embodiments PIF has Uniprot accession number Q53YJ2 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 47; Fermitin family homolog 3 (FERMT3) that is downregulated in patients with an adverse outcome. In preferred embodiments FERMT3 has Uniprot accession number Q86UX7 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 48; Multimerin-1 (MMRN1) that is downregulated in patients with an adverse outcome. In preferred embodiments MMRN1 has Uniprot accession number Q13201 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 49; Protein disulfide-isomerase (PDIA3) that is downregulated in patients with an adverse outcome. In preferred embodiments PDIA3 has Uniprot accession number P30101 (Version 4), for example having the amino acid sequence as set forth in SEQ ID NO. 50; Extended synaptotagmin-1 (ESYT1) that is downregulated in patients with an adverse outcome. In preferred embodiments ESYT1 has Uniprot accession number Q9BSJ8 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 51 ; Peptidyl-prolyl cis-trans isomerise A (PPIA) that is upregulated in patients with an adverse outcome. In preferred embodiments PPIA has Uniprot accession number P62937 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 52; Haptoglobin- related protein (HPR) that is upregulated in patients with an adverse outcome. In preferred embodiments HPR has Uniprot accession number P00739 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 53; Berta-globin (HBB) that is upregulated in patients with an adverse outcome. In preferred embodiments HBB has Uniprot accession number C8C504 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 54; Delta globin (fragment) (HBD) that is upregulated in patients with an adverse outcome. In preferred embodiments HBD has Uniprot accession number D1MGP8 (Version 1 ), for example having the amino acid sequence as set forth in SEQ ID NO. 55; Proline- rich protein 4 (PRR4) that is upregulated in patients with an adverse outcome. In preferred embodiments PRR4 has Uniprot accession number Q 16378 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 56; Ferritin (FTH1) that is upregulated in patients with an adverse outcome. In preferred embodiments FTH1 has Uniprot accession number Q6NZ44 (Version 1 ), for example having the amino acid sequence as set forth in SEQ ID NO. 57; APOLl protein fragment (APOLl) that is upregulated in patients with an adverse outcome. In preferred embodiments APOLl has Uniprot accession number A5PL32 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 58; PRSSl protein (PRSSl) that is upregulated in patients with an adverse outcome. In preferred embodiments PRSSl has Uniprot accession number Q3SY19 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 59; Creatine kinase B-type (CKB) that is upregulated in patients with an adverse outcome. In preferred embodiments CKB has Uniprot accession number PI 2277 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 60; Triosephosphate isomerise (TPI1) that is upregulated in patients with an adverse outcome. In preferred embodiments TPI1 has Uniprot accession number P60174 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 61 ; Putative uncharacterized protein PZP (PZP) that is upregulated in patients with an adverse outcome. In preferred embodiments PZP has Uniprot accession number A6ND27 (Version 4), for example having the amino acid sequence as set forth in SEQ ID NO. 62; Alpha-crystallin B chain (CRYAB) that is upregulated in patients with an adverse outcome. In preferred embodiments CRYAB has Uniprot accession number P0251 1 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 63; Cytochrome b-cl complex subunit 6, mitochondrial (UQCRH) that is upregulated in patients with an adverse outcome. In preferred embodiments UQCRH has Uniprot accession number P07919 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 64; Calcium/calmodulin-dependent protein kinase II alpha (CAMK2A) that is upregulated in patients with an adverse outcome. In preferred embodiments CAMK2A has Uniprot accession number Q8IWE0 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 65; Ferritin (FTL) that is upregulated in patients with an adverse outcome. In preferred embodiments FTL has Uniprot accession number Q6IBT7 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 66; Cartilige oligomeric matrix protein (COMP) that is upregulated in patients with an adverse outcome. In preferred embodiments COMP has Uniprot accession number P49747 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 67; putative protein S that is upregulated in patients with an adverse outcome. In preferred embodiments the putative protein S has Uniprot accession number Q9NSD0 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 68; Ceruloplasmin (CP) that is upregulated in patients with an adverse outcome. In preferred embodiments CP has Uniprot accession number P00450 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 69; Putative uncharactenzed protein RELN (RELN) that is upregulated in patients with an adverse outcome. In preferred embodiments RELN has Uniprot accession number C9J2G2, version 5 represented by SEQ ID NO. 70; Cytochrome c oxyidase subunit 6A1 , mitochondrial (COX6A1) that is upregulated in patients with an adverse outcome. In preferred embodiments COX6A1 has Uniprot accession number PI 2074 (Version 4), for example having the amino acid sequence as set forth in SEQ ID NO. 71 ; COL6A3 protein (COL6A3) that is upregulated in patients with an adverse outcome. In preferred embodiments COL6A3 has Uniprot accession number B7ZW00 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 72; Amyloid protein A (APP) that is upregulated in patients with an adverse outcome. In preferred embodiments APP has Uniprot accession number B2R5G8 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 73; Apolipoprotein M (APOM) that is upregulated in patients with an adverse outcome. In preferred embodiments APOM has Uniprot accession number Q5SRP5 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 74; Vinculin (VCL) that is downregulated in patients with an adverse outcome. In preferred embodiments VCL has Uniprot accession number PI 8206 (Version 4), for example having the amino acid sequence as set forth in SEQ ID NO. 75; Integrin beta-3 (ITGB3) that is downregulated in patients with an adverse outcome. In preferred embodiments ITGB3 has Uniprot accession number P05106 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 76; Platelet glycoprotein lb alpha polypeptide (GP1BA) that is downregulated in patients with an adverse outcome. In preferred embodiments GP1BA has Uniprot accession number A5CKE2, version 1 represented by SEQ ID NO. 77; ATP Synthase subunit beta, mitochondrial (ATP5B) that is downregulated in patients with an adverse outcome. In preferred embodiments ATP5B has Uniprot accession number P06576 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 78; Platelet glycoprotein V (GP5) that is downregulated in patients with an adverse outcome. In preferred embodiments GP5 has Uniprot accession number P40197 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 79; Putative uncharacterized protein ITGA6 (ITGA6) that is downregulated in patients with an adverse outcome. In preferred embodiments ITGA6 has Uniprot accession number C9JK10 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 80; Band 3 anion transport protein (SLC4A1) that is downregulated in patients with an adverse outcome. In preferred embodiments SLC4A1 has Uniprot accession number P02730 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 81 ; Integrin-linked protein kinase (ILK) that is downregulated in patients with an adverse outcome. In preferred embodiments ILK has Uniprot accession number Q 13418 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 82; Sarcoplasmic/endoplasmic reticulum calcium APTase 3 (ATP2A3) that is downregulated in patients with an adverse outcome. In preferred embodiments ATP2A3 has Uniprot accession number Q93084 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 83; Apolipoprotein A- IV (APOA4) that is downregulated in patients with an adverse outcome. In preferred embodiments APOA4 has Uniprot accession number P06727 (Version 3 ), for example having the amino acid sequence as set forth in SEQ ID NO. 84; Integrin alpha-2 (ITGA2) that is downregulated in patients with an adverse outcome. In preferred embodiments ITGA2 has Uniprot accession number PI 7301 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 85; Inverted forming-2 (INF2) that is downregulated in patients with an adverse outcome. In preferred embodiments INF2 has Uniprot accession number Q27J81 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 86; Platelet glycoprotein 4 (CD36) that is downregulated in patients with an adverse outcome. In preferred embodiments CD36 has Uniprot accession number PI 6671 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 87; Beta-2 -glycoprotein 1 (APOH) that is downregulated in patients with an adverse outcome. In preferred embodiments APOH has Uniprot accession number P02749 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 88; Integrin beta-1 (ITGB1) that is downregulated in patients with an adverse outcome. In preferred embodiments ITGB1 has Uniprot accession number P05556 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 89; Ras GTPase-activating protein 3 (RASA3) that is downregulated in patients with an adverse outcome. In preferred embodiments RASA3 has Uniprot accession number Q 14644 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 90; Ficolin-3 (FCN3) that is downregulated in patients with an adverse outcome. In preferred embodiments FCN3 has Uniprot accession number 075636 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 91 ; Platelet endothelial cell adhesion molecule (PECAM1) that is downregulated in patients with an adverse outcome. In preferred embodiments PEC AMI has Uniprot accession number PI 6284 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 92; ATP synthase subunit alpha, mitochondrial (ATP5A1) that is downregulated in patients with an adverse outcome. In preferred embodiments ATP5A1 has Uniprot accession number P25705 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 93; Alpha- 1 -antichymotrysin (SERPINA3) that is downregulated in patients with an adverse outcome. In preferred embodiments SERPINA3 has Uniprot accession number P0101 1 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 94; Plasma protease CI inhibitor (SERPING1) that is downregulated in patients with an adverse outcome. In preferred embodiments SERPING1 has Uniprot accession number P05155 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 95; Protein disulfide-isomerase (P4HB) that is downregulated in patients with an adverse outcome. In preferred embodiments P4HB has Uniprot accession number P07237 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 96; Platelet glycoprotein lb beta chain (GP1BB) that is downregulated in patients with an adverse outcome. In preferred embodiments GP1BB has Uniprot accession number PI 3224 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 97; SLC25A5 protein (SLC25A5) that is downregulated in patients with an adverse outcome. In preferred embodiments SLC25A5 has Uniprot accession number Q6NVC0 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 98; Ras-related protein Rap-IA (RAP1A) that is downregulated in patients with an adverse outcome. In preferred embodiments RAP1A has Uniprot accession number P62834 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 99; Syntaxin-binding protein 2 (STXBP2) that is downregulated in patients with an adverse outcome. In preferred embodiments STXBP2 has Uniprot accession number Q15833 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 100; Anthithrombin-III (SERPINC1) that is downregulated in patients with an adverse outcome. In preferred embodiments SERPINC1 has Uniprot accession number P01008 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 101 ; Calnexin (CANX) that is downregulated in patients with an adverse outcome. In preferred embodiments CANX has Uniprot accession number P27824 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 102; Solute carrier family 2 (SLC2A1) that is downregulated in patients with an adverse outcome. In preferred embodiments SLC2A1 has Uniprot accession number Q0P512 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 103; Alpha-2-antiplasmin (SERPINF2) that is downregulated in patients with an adverse outcome. In preferred embodiments SERPINF2 has Uniprot accession number P08697 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 104; Platelet basic protein (PPBP) that is downregulated in patients with an adverse outcome. In preferred embodiments PPBP has Uniprot accession number P02775 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 105; Lipopolysaccharide-binding protein (LBP) that is downregulated in patients with an adverse outcome. In preferred embodiments LBP has Uniprot accession number PI 8428 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 106; Synaptotagmin-like protein 4 (SYTL4) that is downregulated in patients with an adverse outcome. In preferred embodiments SYTL4 has Uniprot accession number Q96C24 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 107; Syntaxin-4 (STX4) that is downregulated in patients with an adverse outcome. In preferred embodiments STX4 has Uniprot accession number Q 12846 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 108; Synaptotagmin-10 (STY 10) that is downregulated in patients with an adverse outcome. In preferred embodiments STY 10 has Uniprot accession number Q6XYQ8 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 109; Tyrosine-protein kinase (TXK) that is upregulated in patients with an adverse outcome. In preferred embodiments TKX has Uniprot accession number P42681 (Version 3), for example having the amino acid sequence as set forth in SEQ ID NO. 110; Aldehyde dehydrogenase 1 family, member LI variant (Fragment) (ALDH1L1) that is upregulated in patients with an adverse outcome. In preferred embodiments ALDH1L1 has Uniprot accession number Q59G10 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. I l l ; Sodium-dependent phosphate transport protein 2C (SLC34A3) that is upregulated in patients with an adverse outcome. In preferred embodiments SLC34A3 has Uniprot accession number Q8N130 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 1 12; Kinetochore-associated protein 1 (KNTCl) that is upregulated in patients with an adverse outcome. In preferred embodiments KNTCl has Uniprot accession number P50748 (Version 1), for example having the amino acid sequence as set forth in SEQ ID NO. 113; and Cytochrome c oxidase subunit 6B1 (COX6B1) that is upregulated in patients with an adverse outcome. In preferred embodiments COX6B 1 has Uniprot accession number P14854 (Version 2), for example having the amino acid sequence as set forth in SEQ ID NO. 114.
[0071] The term "polypeptide" as used herein in its typical meaning refers to a polymer of amino acids and includes isolated and/or purified polypeptides, with "isolated/purified" meaning that said polypeptide has been separated from at least some other (cellular) components that may accompany it in a given sample. In various embodiments, the polypeptides may be in its natural modified form, for example, glycosylated, acetylated, phosphorylated and the like. In the context of the present invention, the term includes peptides that are 20 to about 1000 amino acids in length.
[0072] The polypeptides may also include fragments or variants of the sequences set forth in SEQ ID Nos. 1-114, comprising sequences preferably 80%, 90% or 95% identical to any one of the sequences set forth in SEQ ID NOS 1-114 over their entire length. The term "percent sequence identity" is taken to include an amino acid sequence which is at least 80%, 90% or 95% identical, preferably at least 98 or 99% identical at the amino acid level over at least 10, 20, 50, 100, 200 or 300 contiguous amino acids with the given marker amino acid sequence. Preferred polypeptides of the invention comprise a contiguous sequence having greater than 80 or 90% identity, to one or more of amino acids set forth in any one of SEQ ID Nos. 1 to 114 within each alternative sequence.
[0073] "Fragments", as used herein, relates to N- or C-terminally shortened derivatives of the polypeptides. Preferably, the fragments are still long enough to be specifically detectable by detection reagents specific for the full length marker. This may mean that they are long enough to comprise amino acid sequences that are characteristic for a given marker. In preferred embodiments, the fragments are at least 20, preferably at least 30 amino acids in length. In other preferred embodiments, the fragments have at least 70, preferably at least 80, more preferably at least 90% of the length of the full length polypeptide.
[0074] In various embodiments the at least one biomarker is selected from the group consisting of polypeptides having the amino acid sequence set forth in SEQ ID Nos. 4, 6, 8, 13, 18, 21 , 25, 31, 44-47, and 52-74 and an increased level is indicative for (i) an unfavorable prognosis, (ii) that said subject has suffered ischemic stroke or (iii) has an increased likelihood to suffer ischemic stroke.
[0075] In such embodiments, the at least one biomarker may comprise 1, 2, 3, 4,
5, 6, 7, 8, 9, 10 or 20 of the biomarkers identified above.
[0076] In various embodiments the biomarker is selected from the group consisting of polypeptides having the amino acid sequence set forth in SEQ ID NOS
12, 19, 27, 28, 48-51 , 75-109 and a decreased level is indicative for (i) an unfavorable prognosis, (ii) that said subject has suffered ischemic stroke or (iii) has an increased likelihood to suffer ischemic stroke.
[0077] Again, in such embodiments, the at least one biomarker may comprise 1 ,
2, 3, 4, 5, 6, 7, 8, 9 or 10 of the biomarkers identified above.
[0078] In various embodiments, the biomarker is selected from the group consisting of polypeptides having the amino acid sequence set forth in SEQ ID Nos. 31 , 44-47 and an increased level is indicative for (i) an unfavorable prognosis, (ii) that said subject has suffered ischemic stroke or (iii) has an increased likelihood to suffer ischemic stroke.
[0079] In various embodiments the biomarker is selected from the group consisting of polypeptides having the amino acid sequence set forth in SEQ ID NOS 28, 48-51 and a decreased level is indicative for (i) an unfavorable prognosis, (ii) that said subject has suffered ischemic stroke or (iii) has an increased likelihood to suffer ischemic stroke.
[0080] In various embodiments, the method using the markers listed above is a method for determining the prognosis of a subject afflicted by lacunar infarction. [0081] A further aspect of the invention relates to a panel of biomarkers for determining the prognosis of a subject afflicted by ischemic stroke, predicting the risk of a subject developing ischemic stroke or diagnosing ischemic stroke in a subject comprising at least one, preferably at least two, more preferably at least 5 biomarkers selected from the group defined above in connection with the described methods.
[0082] The term "panel" as used herein may refer to at least one biomarker, or a plurality of biomarkers such as at least two biomarkers, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, at least 12, at least 14, at least 15, or at least 20 biomarkers the presence or level of which are measured in a sample, and used for determining a diagnosis or prognosis related to ischemic stroke, or for differentiating between a non-adverse outcome and an adverse outcome after a subject has been afflicted by ischemic stroke. Such a panel may be analyzed in a number of fashions well known to those of skill in. the art. For example, each member of a panel may be compared to a "normal" value, or a value indicating a particular outcome. A particular diagnosis/prognosis may depend upon the comparison of each marker to this value; alternatively, if only a subset of biomarkers is outside of a normal range, this subset may be indicative of a particular diagnosis/prognosis.
[0083] In various embodiments each biomarker on the panel may be represented by a suitable detection reagent, whereby the biomarker is detected using the suitable detection reagent. The type of said reagent is dependent on the type of biomarker to be detected. In case the biomarker is a protein, polypeptide or peptide, the detection reagent may, for example, be an antibody or antibody-like molecule or known derivatives thereof. In various embodiments, the detection reagents may also include conjugates of the respective binding moeities, as already defined above.
[0084] In various embodiments the biomarker is selected from the group consisting of polypeptides having the amino acid sequence set forth in SEQ ID NOS 4, 6, 8, 13, 18, 21, 25, 31, 44-47, 52-74 and an increased level is indicative for (i) an unfavorable prognosis, (ii) that said subject has suffered ischemic stroke or (iii) has an increased likelihood to suffer ischemic stroke.
[0085] In various embodiments the biomarker is selected from the group consisting of polypeptides having the amino acid sequence set forth in SEQ ID NOS 12, 19, 27, 28, 48-51, 75-109 and a decreased level is indicative for (i) an unfavorable prognosis, (ii) that said subject has suffered ischemic stroke or (iii) has an increased likelihood to suffer ischemic stroke.
[0086] In various embodiments the biomarker is selected from the group consisting of polypeptides having the amino acid sequence set forth in SEQ ID NOS 31, 44-47 and an increased level is indicative for (i) an unfavorable prognosis, (ii) that said subject has suffered ischemic stroke or (iii) has an increased likelihood to suffer ischemic stroke.
[0087] In all above embodiments, the at least one biomarker may comprise 1, 2,
3, 4, 5, 6, 7, 8, 9 or 10 of the biomarkers identified above.
[0088] In various embodiments, the biomarkers comprise the polypeptides having the amino acid sequences set forth in SEQ ID Nos. 31 , 44-47.
[0089] In various embodiments, the biomarkers comprise the polypeptides having the amino acid sequences set forth in SEQ ID Nos. 31, 44 and 46.
[0090] In various embodiments, the biomarker is selected from the group consisting of polypeptides having the amino acid sequence set forth in SEQ ID NOS 28, 48-51 and a decreased level is indicative for (i) an unfavorable prognosis, (ii) that said subject has suffered ischemic stroke or (iii) has an increased likelihood to suffer ischemic stroke.
[0091] In various embodiments the at least biomarkers comprise polypeptides having the amino acid sequences set forth in SEQ ID Nos. 28, 48-51.
[0092] A further aspect of the invention relates to use of the panel of biomarkers disclosed herein for determining the prognosis of a subject afflicted by ischemic stroke, predicting the risk of a subject developing ischemic stroke or diagnosing ischemic stroke in a subject.
[0093] Also encompassed is a method for determining the prognosis of a subject afflicted by ischemic stroke, predicting the risk of a subject developing ischemic stroke or diagnosing ischemic stroke in a subject by use of the biomarker panel described above.
[0094] It should be understood that all embodiments disclosed above in relation to the methods or uses of the invention, are similarly applicable to each method and use and vice versa.
[0095] As already described above, the therapeutic importance of plasma microvesicles and the technical advantage of the quantitative method holds great promise for understanding the etiology, pathophysiology, and more importantly, prognosis and diagnosis of subjects afflicted by lacunar infarction. The invention described herein results from establishing a proteomic imprint from plasma microvesicle samples of LACI patients. Interestingly, it has been found that the up- regulation of several platelet related proteins including the proteins of integrin pathway and coagulation cascade, probably due to a failure of an anti-platelet therapy, is associated with adverse outcome in the LACI patients. Reverse regulation of MBP and ALB could indicate underlying pathological changes ongoing during the convalescent stage of LACI.
[0096] As the plasma levels of many of the biomarkers identified herein are modifiable via drugs or changes in lifestyle, the perturbed biomarkers alone or 'as a panel' can be tested to stratify the high-risk group of patients on priority for hospital admission, treatment or rehabilitation or to monitor the effect of therapy on the long- term functional outcome of the disease. Conversely, these proteins can also be used as surrogate markers in LACI related clinical trials to monitor the consequences of therapeutic interventions. The described biomarkers thus also facilitate a better understanding of the underlying pathology of LACI affected brain samples.
[0097] Some significantly perturbed microvesicle proteins in the patients with adverse outcomes, including recurrent vascular events and cognitive decline, are identified and listed in Figures 5, 6 and 7. These plasma microvesicle biomarkers as originated from damaged brain tissue are generally applicable for diagnosis and prognosis of stroke, particularly for asymptomatic/silent stroke, LACI and transient ischemic attack (TIA) stroke subtypes.
[0098] By "comprising" it is meant including, but not limited to, whatever follows the word "comprising". Thus, use of the term "comprising" indicates that the listed elements are required or mandatory, but that other elements are optional and may or may not be present.
[0099] By "consisting of is meant including, and limited to, whatever follows the phrase "consisting of. Thus, the phrase "consisting of indicates that the listed elements are required or mandatory, and that no other elements may be present.
[00100] The inventions illustratively described herein may suitably be practiced in the absence of any element or elements, limitation or limitations, not specifically disclosed herein. Thus, for example, the terms "comprising", "including", "containing", etc. shall be read expansively and without limitation. Additionally, the terms and expressions employed herein have been used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the inventions embodied therein herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention.
[00101] The invention has been described broadly and genetically herein. Each of the narrower species and sub-generic groupings falling within the generic disclosure also form part of the invention. This includes the generic description of the invention with a proviso or negative limitation removing any subject matter from the genus, regardless of whether or not the excised material is specifically recited herein.
[00102] Other embodiments are within the following claims and non- limiting examples.
EXAMPLES [00103] Examples 1-18 detail the identification of biomarkers that can be used to, diagnose a patient that has had an ischemic cerebral small-vessel disease (SVD), including lacunar infarction (LACI), asymptomatic/silent stroke, and transient ischemic attack (TIA) stroke subtypes or to prognose the likelihood of adverse effects after a subject has suffered a lacunar infarction (LACI).
[00104] Examples 19 and 20 detail optimization of the method of isolating microvesicles from plasma.
[00105] Examples 21-24 detail the validation of a panel of the identified biomarkers to, diagnose a patient that has had a ischemic cerebral small-vessel disease (SVD), including lacunar infarction (LACI), asymptomatic/silent stroke, and transient ischemic attack (TIA) stroke subtypes or to prognose the likelihood of adverse effects after a subject has suffered a lacunar infarction (LACI). Reagents
[00106] Unless indicated, all reagents were purchased from Sigma- Aldrich (St. Louis, MO).
Example 1: Sample Collection [00107] Plasma was collected from forty five patients following a non-disabling LACI along with seventeen age/vascular risk factor-matched control subjects. The LACI patients were monitored prospectively for up to five years for the occurrence adverse outcomes (i.e. recurrent vascular events or cognitive decline). Microvesicles isolated from the pooled plasma by sequential centrifugation of four groups (control, n=17; LACI-no adverse outcome, n=19; LACI-recurrent vascular event, n=l l ; and LACI-cognitive decline without any recurrence of vascular events, n= 15) were profiled by an iTRAQ-2D-LC-MS/MS approach to identify the differential proteomic signature. The plasma samples were obtained from patients with a non-disabling ischemic stroke who were recruited at the Singapore General Hospital between 1999 and 2005 for the cognitive sub-study of the European Australasian Stroke Prevention in Reversible Ischemia Trial (ESPRIT-cog). Detailed methodology of ESPRIT and ESPRIT-cog including the exclusion criteria has been reported previously. Briefly, for ESPRIT, patients were eligible if they were within 6 months of a transient ischemic attack (including transient monocular blindness) or a non-disabling ischemic stroke (grade <3 on the modified Rankin scale [mRS]) (Bonita, R.; Beaglehole, R., Stroke 1988, 19, 1497-1500) of presumed arterial origin. Stroke subtype was classified according to the Oxfordshire Community Stroke Project (OCSP) as total anterior circulation infarct (TACI), partial anterior circulation infarct (PACI), posterior circulation infarct (POCI), or LACI. All patients were randomized to either aspirin (100 mg/day) or aspirin combined with dipyridamole (75-450 mg/day). The control plasma was collected from non-stroke subjects at the same site during 2004-2006. EDTA was used as the anti-coagulant during the processing of blood samples.
Example 2: Standard Protocol Approvals, Registrations, and Patient Consents
[00108] The study protocol was approved by Singapore General Hospital's and Nanyang Technological University's Institutional Review Board and Ethics Committee. Written informed consent was obtained from all patients or legal guardians. The ESPRIT trial was registered under http://clinicaltrials.gov with the identifier NCTOOl 61070. Example 3: Neuropsychological Test Battery - Determination of Cognitive Impairment
[00109] The cognitive status of the patients was determined by trained research psychologists using standard neuropsychological test battery that has been validated for use in Singapore. Details of the procedure has been described previously (Narasimhalu, K.; Ang, S.; De Silva, D. A.; Wong, M. C; Chang, H. M.; Chia, K. S.; Auchus, A. P.; Chen, C. P., The prognostic effects of poststroke cognitive impairment no dementia and domain-specific cognitive impairments in nondisabled ischemic stroke patients. Stroke 2011, 42 (4), 883-8) incorporated herein by reference. Briefly, the battery assessed 6 domains; 2 memory domains (i.e. Verbal Memory and Visual memory) and 4 non-memory domains (Attention, Language, Visuomotor speed and Visuoconstruction). Failure in at least half of the tests in a domain constituted failure in that domain. Diagnoses of dementia were made according to the DSM-IV criteria.19 The patients who did not qualify to be demented, included individuals with diagnoses of cognitive impairment no dementia (CIND) -mild (impairment of 1-2 domains), CIND -moderate (impairment of 3-6 domains) and no cognitive impairment (NCI).
Example 4: Experimental Design guided by Outcome Measures
[001 10] This proteomic study is an analysis of 45 selected plasma samples out of 289 LACI patients, enrolled in the ESPRIT cohort at the Singapore site. The experimental design is described in Figure 1. The cognitive status of the LACI patients was determined at the baseline (3-4 months after the qualifying event) using standard neuropsychological test battery. Accordingly, the LACI patients were classified in any of the four groups namely, NCI, CIND-mild, CIND-moderate and dementia. Any patients who were demented at the baseline were excluded from this study. Next, the patients were followed up yearly up to a maximum of 5 yrs to document their cognitive status. The LACI Patients whose cognitive status declined from the respective baseline status during the course of the prospective study had been assigned in the "cognitive decline" group. The LACI patients were also monitored for the occurrence of any vascular event annually for up to 5 years. Strokes, peripheral artery disease, intracranial bleeds, and any cardiac ischemia (stable and unstable angina, myocardial infarctions) or deaths from any of the above were considered to be a recurrent vascular event. Any LACI patient having a recurrence of vascular event during the follow-up period was included in the group called "recurrent vascular event". Patients who did not suffer a recurrence or cognitive decline during this period were named as "LACI, no adverse outcome". Accordingly, plasma samples of 45 LACI patients were divided into three groups based on the outcome variables (LACI- no adverse outcome, n=19; LACI- recurrent vascular events, n=l l ; LACI - cognitive decline but no recurrent vascular events, n=15). The age-matched control group had 17 subjects who never had a stroke or cancer and were cognitively normal at the baseline.
[001 11] The plasma samples were pooled group-wise before processing. Microvesicles were isolated by sequential centrifugation and were labeled with isobaric tags followed by 'two dimensional liquid chromatography' to improve the depth of identification and quantification. The iTRAQ samples were injected thrice in the MS machine (technical replicate = 3).
[001 12] Blood-based biomarker studies in the area of ischemic stroke mostly correlated acute levels of biomarkers (within first week after stroke onset) to short term outcome (e.g. death, disability or infarct volume) without focusing on certain subtypes of ischemic stroke. Most of the investigational biomarkers are proteins of extra-cranial source that are related to inflammation, cardiovascular system and hemostasis apart from few proteins of brain origin. The study, being a profiling approach, has identified differentially regulated peripheral as well as brain-specific candidates targeting only lacunar stroke in a single experiment, while relating them to long-term outcome measures such as cognitive decline and recurrent vascular events. In addition, the plasma was collected during the convalescent phase following the index event to evade the acute systemic response that may confound data interpretation. Example 5: Separation of Plasma Microvesicles by Sequential Centrifugation
[001 13] Frozen individual plasma samples were thawed on ice and pooled in a group-wise manner to obtain four tubes containing around 5 ml of plasma specimens from each group. The samples were subjected to sequential centrifugation to isolate the microvesicles using a modified protocol as described previously (Grant, R.; et al. Journal of Immunological Methods 2011, 371 (1-2), 143-51). Briefly, sonicated plasma (5 X 1 min) was centrifuged at 4000g twice for 30 min and then at 12 OOOg for 30 min to collect and remove the pellets for separate studies. The resulting supernatant was subsequently diluted approx. five times with ice-cold IX PBS before doing ultra-centrifugation at 30 OOOg for 2 h to collect the pellet of plasma membrane derived vesicles. The supernatant was ultra-centrifuged again at 200 OOOg for 2 h 15 min to collect the microvesicle pellet (Figure 2). The microvesicle pellets were washed at least twice with IX PBS and were lyophilized. The lyophilisate was dissolved using 50-100 μΐ of ice-cold dissolution buffer [6% sodium dodecyl sulfate; 20 mM dithiothreitol (DTT), 100 raM tris-HCl with Complete Protease Inhibitor Cocktail (COMPLETE, (Roche; Mannheim, Germany)), pH 7.75] by brief vortexing. Protein quantization was performed using 2-D Quant kit (Amersham Biosciences, Piscataway, NJ).
Example 6: In-Gel Tryptic Digestion and Isobaric Labeling [001 14] The samples (500 μg / condition) were subjected to denaturing PAGE using a 4% - 6% - 25% gel following an identical procedure as described previously in Datta et al.. Briefly, after overnight in-gel digestion and extraction of the peptides, the dried peptides were reconstituted into 0.5 M triethylammonium bicarbonate (TEAB) and labeled with respective isobaric tags of 4-plex iTRAQ Reagent Multi- Plex kit (Applied Biosystems, Foster City, CA) as follows: Control, 114; LACI-no adverse outcome, 1 15; LACI- recurrent vascular events, 1 16; LACI - cognitive decline but no recurrent vascular events, 117 (Figure 1). Two parallel iTRAQ experiments were run one each for plasma membrane derived vesicles and exosomes. Example 7: Electrostatic Repulsion and Hydrophilic Interaction Chromatography (ERLIC)
[001 15] The combined iTRAQ sample was desalted by Sep-Pak C18 SPE cartridges (Waters, Milford, MA). A modified ERLIC using volatile salt-containing buffers was adopted. The dried iTRAQ-labeled peptide was reconstituted in 200 μΐ of Buffer A (10 mM NH4HC02 , 85% ACN, 0.1% formic acid (FA)) and fractionated using a PolyWAX LP column (200 χ 4.6 mm; 5 μιη; 300 A) (PolyLC, Columbia, MD) on a Prominence HPLC system (Shimadzu, Kyoto, Japan) in a 65 min gradient with Buffer B (30% ACN, 0.1% FA). The HPLC gradient was composed of 100% buffer A for 10 min; 0-25% buffer B for 35 min; then 25-100% buffer B for 10 min; followed by 100% buffer B for 10 min. The chromatogram was recorded at 214 nm. Eluted fractions were collected in every 1 min, and then pooled into 34 fractions depending on the peak intensities, before drying them in a vacuum centrifuge. They were stored at -20 °C till MS analysis. Most of the MS parameters were also kept similar except minor modifications. The maximum accumulation time was set at 1.0 s instead of 2.0 s that was used previously (Datta, A.; et al. Journal of Proteome Research 2011, 10 (1 1), 5199-213) incorporated herein by reference.
Example 8: Reverse Phase LC-MS/MS Analysis using QSTAR
[00116] The iTRAQ-labeled peptides were reconstituted with 0.1% FA, 3% ACN and analyzed using a HPLC system (Shimadzu) coupled with QSTAR Elite Hybrid MS (Applied Biosystems/MDS-SCIEX) as described previously with minor modifications. Briefly, most of the LC parameters for a 90 min gradient including column configuration, gradient and flow rate were kept constant except the mobile phase A composition (0.1% FA in 3% ACN) and sample injection volume (15 μΐ/injection). Regarding MS parameters, the precursors with a mass range of 300- 1600 m/z and calculated charge of +1 to +5 were selected for the fragmentation. The selected precursor ion was dynamically excluded for 20 s with a 50 mDa mass tolerance. All other parameters were kept identical as reported previously. The peak areas of the iTRAQ reporter ions reflect the relative abundance of the proteins in the samples. Example 9: Mass Spectrometric Raw Data and Bioinformatics Analysis
[001 17] The Analyst QS 2.0 software (Applied Biosystems) was used for the spectral data acquisition. ProteinPilot Software 3.0, Revision Number: 1 14 732 (Applied Biosystems) was used for the peak list generation, protein identification and quantification against the concatenated target-decoy Uniprot human database (total 191242 proteins). Details of the analysis strategy have been described previously (Datta et al. 201 1).
Example 10: Bioinformatics Analysis
[00118] The bioinformatics analysis was performed using different attributes such as gene ontology (GO), pathway, protein interaction, tissue specificity, keywords or protein domains of DAVID to extract out hidden trends and enrichment of certain groups of proteins. DAVID uses modular enrichment analysis where the term- term/gene-gene relationships are considered for enrichment p-va\ e calculation. It calculates the probability of the number of genes in the list that hit a given biology class as compared to pure random chance with the aid of Fisher's exact test (Huang da, W.; et al. Nucleic Acids Research 2009, 37 (1), 1-13). The enriched list of annotations only facilitates a rational exploration as final selection is purely based on a priori biological knowledge of the pathology of interest. It is not uncommon to ignore specific group of proteins even with an extremely good ?-value.
[001 19] Data mining revealed (1) significant up-regulation of a group of proteins (e.g. MB P and GFAP) from brain tissue in the plasma microvesicles and proteins related to the coagulation cascade (e.g. FGA, FGB) and focal adhesion (e.g. ITGA2B, TLN1 , and FLNA); (2) significant down-regulation of ALB, in the plasma microvesicles of groups of patients with adverse outcome in comparison with patients with no adverse outcome, when age-matched control group was used as a common background. This panel of candidates could be useful as surrogate markers in LACI related clinical trials.
Example 11: Western Blot (WB) Analyses
[00120] WB was performed after SDS-PAGE by probing with primary antibodies at the indicated dilutions: anti-ALB (albumin, 1 :5000, rabbit polyclonal; Abeam, Cambridge, UK) and anti-MBP (MBP, 1 :1000, goat polyclonal; Santa Cruz Biotechnology, CA., USA). 40μg of proteins were used for WB. The membranes were incubated with the respective secondary antibodies from Sigma at 1 :5000 dilutions (anti-rabbit HRP and anti-goat HRP). Immunoreactivity was detected by using an HRP chemiluminescent substrate reagent kit (Invitrogen, Carlsbad, CA).
[00121] MBP was detected to be significantly increased in individuals having recurrent vascular events compared to controls (Figure 12).
Example 12: Patient demography [00122] The demographic characteristics of the study population are summarized in Figure 2. Overall, the groups were not significantly different in terms of baseline cognitive classification or demographic characteristics.
Example 13: Proteomics
[00123] The plasma microvesicles were isolated in order to enrich the low abundant proteins during the bottom-up quantitative profiling. The microvesicles provided a reservoir of potential biomarkers.
[00124] The discovery of circulatory biomarkers for neurological disorders represents an additional challenge as brain parenchyma remains selectively accessible by the systemic circulation due to the presence of blood brain barrier (BBB) under the physiological condition. This makes blood an indirect reflector to sense any events happening inside the brain tissue. However, different cell types in the brain (e.g. microglia and oligodendrocytes) are reported to release microvesicles for delivering signals to the neighboring cells and external environment. A fraction of these microvesicles may drain into the cerebrospinal fluid (CSF) or eventually in the blood. In addition, ischemic small vessel disease is well-known to cause an endothelial dysfunction and a diffuse increase in the BBB permeability that may facilitate the leakage of microvesicles in the general circulation. Hence, profiling of circulatory microvesicles by quantitative proteomics during the post-stroke recovery phase may provide a technically and conceptually preferred strategy to investigate the on-going neuro-pathological processes and to discover useful prognostic markers. Example 14: Quality Control and Filtering of iTRAQ Data Set
[00125] To minimize the false-positive identification of proteins, a strict cutoff of unused prot-score >3 was used as the qualification criteria, which resulted in the identification of 183 proteins with a FDR of 1.1 %. Around 97% of the identified proteins had .2 unique peptides having a confidence of >95%. Decreasing the unused prot-score cut-off to widely used >2.0 although increases the number of identified proteins (288 proteins); makes the FDR unacceptably high (>1 1%). Similar observation is however been reported in a study dealing with shotgun proteomics of plasma samples (Tu, C; et al. Journal of Proteome Research 2010, 9 (10), 4982- 4991). Hence, the result reported here are either comparable (Mathivanan, S.; et al. Journal of Proteomics 2010, 73 (10), 1907-20) or even better (Yadav, A. K.; et al. PLoS ONE 2011, 6 (9), art. no. e24442) than similar published reports in the recent past. Moreover, all these studies addressed technical issues only and none of them tried to quantify the proteome. The current approach not only provided quantitative information of these proteins but also used a simpler protocol to achieve this.
[00126] Next, a cut-off of /7-value <0.05 was used for filtering the proteins with significant ratios from each condition. There were 17, 33 and 28 proteins for the three ratios (i.e. 1 15/1 14, 1 16/1 14 and 1 17/1 14) respectively with an acceptable (-value after excluding the keratins from the list. Based on the statistical evaluation of the Proteinpilot software, these values are considered as real and not due to random technical variations. Of note, this ^-value is not related to the biological variation as a pooling strategy was adopted during the proteomic sample preparation. The groups with adverse outcome (either recurrent vascular event or cognitive decline) following a single LACI event had higher percentage of perturbed proteins in the plasma microvesicles in comparison with the LACI patients with a good recovery profile. Overall, 43 proteins having at least one ratio with an acceptable level of confidence were shortlisted for bio informatics analysis to retrieve useful biological trends (Figure 4). Taken together, the significantly perturbed microvesicle proteins in the patients with adverse outcomes, including recurrent vascular events and cognitive decline, are listed in Figures 5,6 and 7. These plasma microvesicle biomarkers as originated from damaged brain tissue are generally applicable for diagnosis and prognosis of stroke, particularly for asymptomatic/silent stroke, LACI and transient ischemic attack (TIA) stroke subtypes.
Example 15: Bioinformatics Analysis of perturbed plasma proteome
[00127] Uniprot accession numbers of the filtered (i.e. 43 proteins) list of proteins was uploaded in DAVID to compare them with the human proteome which was used as the background. To check the enrichment, p-value .=0.01 and FDR <1% was used as cut-off Initially, the enrichment in terms of tissue specificity was checked using the 'UP TISSUE' module. The 43 proteins were assigned to nine different tissues that include plasma, liver, platelet, serum. As expected, 'plasma' secured the top slot with 23 proteins. The GO analysis indicated complementary trends as 'extracellular region or space' and 'platelet alpha granule' were listed as the most significantly enriched 'cellular component'. Searching for enriched pathways according to KEGG or BIOCARTA showed 'complement and coagulation cascades' and 'focal adhesion' as significantly over-represented. GO analysis in the 'biological process' category shortlisted 'acute inflammatory response', 'lipid transport' and 'response to wounding' as some of the perturbed processes whereas 'enzyme (peptidase and endopeptidase) inhibitor activity' was the key 'molecular function' that was enriched in the LACI patients.
[00128] The proteins related to complement and coagulation cascade exhibited a differential and mixed trend between groups with adverse and no adverse outcome. Proteins like FGB were down-regulated, while PLG, C5 and C3 were up-regulated in LACI patients with no adverse outcome. An opposite trend was seen for all of them in the groups with adverse outcome. In contrast, the lipoproteins did not show a differential regulation between groups. Most of the lipoproteins (APOE, APOA1, APOA2 and APOL1) were down-regulated except LPA which was significantly up- regulated across the LACI groups in comparison with the control. Despite that, the magnitude of deregulation was generally higher (e.g. LPA, APOA1) in groups with adverse outcome when compared with the group with no adverse outcome. Proteins related to 'enzyme inhibitor activity' (e.g. C5, C3, PROSl and ITIH4) were generally up-regulated in LACI group with better outcome and down-regulated in LACI groups with adverse outcome. Interestingly, proteins related to 'focal adhesion' (e.g. ITGA2B, TLN1 , FLNA) were down-regulated in LACI patients with no adverse outcome while up-regulated in groups with adverse outcome. Overall, the trends of regulation of the significantly perturbed proteins in both groups with adverse outcome (recurrent vascular events and cognitive decline) were similar in most cases (except FGG, C4BPA) amid differences in magnitudes only. Intriguingly, the extent of deregulation is generally more for the 'recurrent vascular event' group compared to the 'cognitive decline' group. This could indicate the involvement of vascular abnormality in both groups which may remain at a subclinical stage in the patients with cognitive decline.
Example 16: Up-regulation of Integrin Signaling - Failure of Aspirin Therapy [00129] Down-regulation of some candidates from the coagulation cascade (e.g. FGB) and integrin signaling pathway (e.g. ITGA2B, FLNA and TLN1) and up- regulation of PLG in the LACI patients was associated with no adverse outcome. PLG is secreted as a zymogen and activated by proteolysis through tissue plasminogen activator to generate plasmin, which dissolves fibrin in blood clots and helps to restore circulation. ITGA2B or Integrin alpha-IIb/beta-3 (θί\κβιη) or CD41 is a platelet membrane glycoprotein and receptor for diverse ligands including fibronectin, fibrinogen, PLG, prothrombin, and thrombospondin. Activated ITGA2B mediates platelet spreading and aggregation on vascular surfaces during hemostasis and thrombosis. It has been shown that TLN1 can independently activate β integrin by binding on its cytoplasmic tail (Ye, F.; et al. Journal of Cell Biology 2010, 188 (1), 157-73). FLNA on the other hand can compete with TLN1 for binding to integrins, thereby regulating its activation under certain circumstances (Kiema, T.; et al. Molecular Cell 2006, 21 (3), 337-47). In a recent study, involvement of TLN1- dependent activation of ITGA2B or Racl in platelets has been demonstrated for late phase stability of thrombus on undisrupted endothelial cells (Nishimura, S.; et al. Blood 2011, doi: 10.1182/blood-2011-09-381400). Thus, the overall suppression of integrin signaling in patients with no adverse outcome is complementary to the down- regulation of its ligands (FGA or FGB) and up-regulation of PLG. Aspirin has been reported to partially inhibit the inside-out ITGA2B signaling apart from its anti- platelet action (Bhatt, D. L.; Topol, E. J., Nature Review Drug Discovery 2003, 2 (1), 15-28.). Considering all LACI patients were on aspirin therapy, down-regulation of the pro-aggregatory platelet proteins and suppression of proteins from integrin signaling pathway in platelet should be related to the desired anti-thrombotic effect. This speculation was further validated as all the above-mentioned proteins (i.e. ITGA2B, TLNl , FLNA, FGA, FGB, and PLG) showed opposite or no regulation in both groups with adverse outcome (Figure 8A). High plasma fibrinogen is well- studied to be an independent risk factor for stroke and is associated with an increased risk of recurrent cardiovascular events, when stroke sub-types were not specified (Resch, K. L.; Ernst, E.; Matrai, A.; Paulsen, H. F., Fibrinogen and viscosity as risk factors for subsequent cardiovascular events in stroke survivors. Ann. Intern. Med. 1992, 117 (5), 371-5). In another study dealing with small vessel disease in particular, a positive correlation was obtained between fibrinogen level and the amount of leukoaraiosis (Marti-Fabregas, J.; et al. Eur. Neurol. 2002, 48 (4), 185-90). Fibrinogen is one of the main determinants of plasma viscosity. Thus, higher levels of fibrinogen in surviving LACI patients may aggravate the cerebrovascular dysfunction through hemorheologic impairment or by inducing a state of hypercoagulability.
Example 17: Up-regulation of Brain-specific MBP - predictor of poor outcome
[00130] The results clearly identified MBP with five unique peptides (unused score = 10.7) by a proteomic profiling approach justifying the utility of this tool for sensitive detection of low abundant plasma proteins. The result indicates that significantly higher MBP concentration during convalescent stage is associated with adverse outcome which is consistent with previous reports. BBB abnormality is generally more diffuse in small vessel stroke compared to non-lacunar stroke subtypes that may cause gradual and sustained leakage of brain-specific MBP into general circulation. Hence, the release of MBP, which is a structural component of CNS myelin and a marker of oligodendrocyte, either signifies an increased glial injury or an increased permeability of the BBB. Both of these may be responsible for the recurrent vascular event or cognitive decline in the groups with adverse outcome. Leaked MBP along with other CNS specific proteins may also act as antigenic signals to activate systemic immune response that could exacerbate the ischemic injury through inflammatory pathways. Example 18: Down- regulation of ALB - indicative of poor outcome
[00131] The results show that significant down-regulation of plasma ALB is associated with adverse outcome among the surviving LACI patients Figure 8B. Several clinical studies have reported higher concentration of circulatory ALB at admission which is predictive of a better functional outcome and lower mortality in ischemic stroke patients (Idicula, T. T.; et al. Cerebrovasc. Dis. 2009, 28 (1), 13-7.). However, for the first time, a complementary trend is observed by focusing on patients with non-disabling lacunar stroke only. ALB is known to be neuroprotective in preclinical animal models of stroke and is under clinical trial as a potential neuroprotective agent (Belayev, L.; et al. Stroke 2001, 32 (2), 553-60). It might play a beneficial role through its antioxidant, prothrombolytic action or by promoting and sustaining perfusion in the cerebral microcirculation (Nimmagadda, A.; et al. Stroke 2008, 39 (1), 198-204).48 Hence, a procoagulatory condition as discussed previously is complementary with the down-regulation of ALB in the groups with poor outcome.
[00132] A panel of plasma micro vesicles' proteins such as Integrin-linked protein kinase, and other proteins targeting different aspects of the pathology (e.g. endothelium dysfunction and blood brain barrier abnormality) of lacunar infarction (LACI) are differentially present in patients' plasma compared to the healthy population. These aberrant regulations are associated with either the recurrence of vascular events or decline in cognitive functions.
Example 19: Adapted method of isolating microvesicles from plasma
[00133] Noting that 5ml of plasma from LACI patients and controls were initially used to identify the biomarker by iTRAQ quantitative proteomics. A method was developed to use less than 500μ1 of human plasma for the detection of microvesicle biomarkers from individual patients. This quantity may easily be obtained for an exploratory blood test in LACI patients. An ultracentrifugation protocol was adapted first using a sucrose density gradient to isolate plasma microvesicles.
[00134] Several Biomarkers were detected in Orbitrap Elite whereby around 15 times fold of increase in MBP was identified by label free MS/MS in individual LACI patients with recurrent vascular events compared to controls using 500/xl of plasma (Figure 13 A). [00135] MBP differences in microvesicles fraction from 500μ1 were also validated by Western blot. The Western blot results show the high detection sensitivity after the use of the ultracentrifugation protocol (Figure 13B) Example 20: Adapted method for quickly isolating microvesicles from plasma
[00136] Noting that the above established ultracentrifugation protocol requires multiple complex steps, is long (2 days) and difficult to perform, a simpler protocol was developed to improve the isolation of microvesicles using smaller plasma volume (between ΙΟΟμΙ. and 500μ1.). This is expected to increase the biomarker detection sensitivity for a successful identification with a detection kit. The affinity of the microvesicle membrane proteins for hydrophobic microenvironments was taken into account during the development of the new protocol. The method used "soluble protein precipitation for microvesicle purification method" to selectively precipitate and remove soluble proteins in the samples, leaving behind the soluble membrane enclosed microvesicles in the supernatant. Thus microvesicles can be separated from the soluble proteins in the samples. As an example, organic solvents such as acetone, acetonitrile and methanol can be used for soluble protein precipitation for microvesicles isolation.
[00137] During the application of the new protocol the plasma samples are initially mixed with organic solvent (acetone, acetonitrile and methanol) to procure the precipitation of soluble proteins and the formation of protein pellet. A spin at 15000rpm is next performed to the mix. Once the pellet has been structured the supernatant is collected. The supernatant fraction containing the microvesicles can be used for further study of the isolated microvesicles.
[00138] The new protocol shows high isolation capacity from only 100 μΐ of plasma to detect and discriminate the MBP presence in LACI patients that exhibit recurrent vascular events (Figure 14).
[00139] Changes on the MBP biomarker intensity between individual LACI subjects has been clearly established in these experiments. MBP can be considered a good biomarker for prediction of recurrent stroke and cognitive decline in LACI subjects.
[00140] Improvements on the microvesicles isolation protocol for sensitive identification using smaller amount of plasma (ΙΟΟμΙ) has been established. The protocol can be performed in about 1 hour. This ensures the good performance of a kit for detection of MBP and other biomarkers in plasma microvesicles of LACI subjects. Example 21: Selection of biomarkers to diagnose LACI and predict outcome after LACI
[00141] A panel of 20 selected candidates including GFAP (SEQ ID NO. 46), CKB (SEQ ID NO. 60), PPBP (SEQ ID NO. 105), SYTL4 (SEQ ID NO. 107), APOM (SEQ ID NO. 74), DPYL2 (SEQ ID NO. 45), APP (SEQ ID NO. 115), MBP (SEQ ID NO. 31), PIF (SEQ ID NO. 47), TPI1 (SEQ ID NO. 61), FTH1 (SEQ ID NO. 57), TXK (SEQ ID NO. 1 10), ALDH1L1 (SEQ ID NO. I l l), NPT2C (SEQ ID NO. 1 12), KNTC1 (SEQ ID NO. 113), CX6B1 (SEQ ID NO. 114), ITA2B (SEQ ID NO. 28), STX4 (SEQ ID NO. 108), RASA3 (SEQ ID NO. 90), and BCHE (SEQ ID NO. 44), has been selected for a dual validation strategy of Multiplex Luminex Technology and mass spectrometric multiple reaction monitoring-based targeted proteomic approach in a large (n=200) prospectively studied cohort of LACI and control (healthy and large vessel disease) patients. Example 22: Sample collection
[00142] The plasma samples for the validation study came from the same cohort of LACI patients and controls described in Example 1 above, but include different patients. The LACI patients were grouped based on different outcomes (i.e., recurrent vascular events but no cognitive decline, incident cognitive decline and no adverse outcome) in the similar fashion as done previously (Figure 2). The samples have been collected for a prospective study along with the baseline risk factor profile, cognitive status and outcome details following the protocol as mentioned previously (Figure 2).
[00143] Figure 11 describes the final phase involving larger groups (n= 20- 100/group, patients) of LACI patients and age-matched healthy (n= 250) and LDV (n= 35) controls (Phase II in Figure 11). Although, the number of patients in the subgroups based on outcome following LACI is variable; the total number of LACI patients is 160.
[00144] Most of the contemporary biomarker studies for stroke suffer from a common problem in the experimental design due to the lack of a mimicking control (control samples having pathophysiological or etiologic similarity with the target disorder). The resulting biomarkers although sensitive and specific with respect to healthy control fails subsequently especially on the scale of specificity when symptomatically similar patients having a different disorder are included. To address this, a group of LDV patients (n= 15 + 35) are included at two phases of the validation study to improve the specificity of the selected biomarkers.
Example 23: Validation of Candidate Biomarkers
23.1 Microvesicles (Exosome and PMV (plasma membrane derived vesicle)) Isolation
[00145] Already optimized differential centrifugation based microvesicles' isolation strategy was used or an alternative centrifugation- free protocol for exosome isolation only using the commercial reagent Exoquick (System Biosciences). Alternatively, the isolation techniques described in examples 19 and 20 above were used.
[00146] For the ultracentrifugation method the crude plasma was sequentially centrifuged (initially at 4000g) and subsequently with the supernatants from previous centrifugation at different speeds (12 OOOg, 30 OOOg and 200 OOOg) to collect the pellets. This differential centrifugation helps to reduce the sample complexity and provides moderately pure PMV and exosomes at 30 OOOg and 200 OOOg respectively. The PMV and exosomes will be used for subsequent analysis. Alternatively, the commercial reagent Exoquick (System Biosciences) will be used for specifically isolating the exosomes by starting with as little as 100-250 μΐ of plasma following the manufacturer's protocol. This is a one-step precipitation protocol to enrich the exosomes from plasma. The choice will depend on the available plasma amount and compatibility with the downstream validation techniques. 23.2 Luminex Assay
[00147] The protein extraction by using commercial 'complete lysis M buffer' (Roche has been found to be compatible with the Luminex assay with reproducible results. Multiplex Luminex Technology is built on proven, existing technology. Featuring a flexible, open-architecture design, Luminex technology can be configured to perform a wide variety of bioassays quickly, cost-effectively and accurately. First, Luminex color-codes tiny beads, called microspheres, into 100 distinct sets. Each bead set can be coated with a reagent specific to a particular bioassay, allowing the capture and detection of specific analytes from a sample. Within the Luminex compact analyzer, lasers excite the internal dyes that identify each microsphere particle, and also any reporter dye captured during the assay. Many readings are made on each bead set, further validating the results. In this way, this technology allows multiplexing of up to 100 unique assays within a single sample, both rapidly and precisely. This combines the power of flow cytometry with the simplicity of an ELISA plate reader. The multiplex Luminex assay format differs from conventional ELISA in one significant way: the multiplex capture antibody is attached to a polystyrene bead whereas the ELISA capture antibody is attached to the microplate well.
[00148] A Luminex bead assay that uses two antibodies and a recombinant protein was established. A Luminex assay for a marker protein is considered suitable for quantitative protein analysis in this (research) phase of the project when the criterion of good linear response of the calibrators is met. 23.3 Quantitative enzyme-linked immunosorbent assay (ELISA)
[00149] ELISA kits are vastly used in clinical diagnostic and clinical research for their reliability and simplicity of use. Sandwich ELISA displays high sensitivity and excellent specificity for the detection and quantitation of a specific protein from a small amount of sample. ELISA kits containing specific antibodies against the following biomarkers (myelin basic protein, MBP; butirylcholinesterase, BCHE; dermicidin, PIF; glial fibrillary acidic protein, GFAP; dihydropirimidinase-related protein 2, DPYSL2, and others) have been made for use in quantifying the biomarker level in plasma microvesicle.
[00150] The specific detection antibody against the biomarker antigen is pre- coated into the microplate, the standards provided and our subject samples are pipetted into the wells and any biomarker present in the sample is bound by the immobilized antibody. After removing any unbound substances, a biotin-conjugated antibody specific for the biomarker is added to the wells. After washing, avidin conjugated Horseradish Peroxidase (HRP) is added to the wells. Following a wash to remove any unbound avidin-enzyme reagent, a substrate solution is added to the wells and color develops in proportion to the amount of biomarker bound to the specific detection antibody in the initial step. The color development is stopped and the intensity of the color is measured. The minimum amount of biomarker detectable by ELISA kits is typically less than 0.05 ng/ml. The intra and inter-assay precision of typical kits is in a range between 8-10% of CV%.
[00151] One of the principal advantages of the use of the ELISA kits is the possibility to rapidly validate the presence and the respective amount of each biomarker from the exosomal fraction in a big number of subjects (almost 90 each kit), including sample from all the predicted subjects in a short period of time.
23.4 Mass Spectrometric (MRM) Quantization for Validation of Candidate Biomarkers
[00152] When no antibody combinations plus recombinant proteins are available for the Luminex assay, targeted proteomics with MRM technology is adopted using a triple quadrupole (QqQ-MS) mass spectrometer (Agilent Technologies Inc.) as an alternative approach.
[00153] This mass spectrometry-based method is capable of multiplex quantification of proteins in a single experiment. This MRM approach monitors and quantifies the specific peptides of candidate proteins in a complex mixture. Absolute quantization (AQUA) of specific proteins in a complex mixture is achievable by internal addition of stable isotope labeled synthetic peptides.
[00154] Many candidate biomarkers do not have commercial antibody or recombinant proteins available. MRM assay is an antibody-free approach, so applicable to novel proteins for which generating an antibody in-house may be cumbersome, time-consuming and costly. The added advantage of MRM assays are their improved sensitivity and specificity, the speed at which the assays can be developed and the quantitative nature of the assay. Thus, the chances of success will become higher due to the complementary nature of both approaches and their multiplicity. 23.4 Proteomics Sample Preparation
[00155] The quantization in MRM technology happens at the level of peptides. Thus, the upstream sample handling (i.e., extraction or digestion protocol) is identical and standard operating procedure will be followed. The lyses of the microvesicles is done in 40 - 100 μΐ of lyses buffer (6% SDS, 20 mM DTT, protease inhibitor cocktail (complete), 100 mM Tris-Cl, pH 7.75). Protein concentration is measured by 2-D Quant kit.
[00156] For each candidate biomarker protein, four unique peptides are chosen for synthesizing stable isotope labeled heavy peptides for absolute quantization.
Example 24: Identification of Biomarkers in individual subjects [00157] Less than 500μ1 of plasma from control and LACI individuals were used to isolate the microvesicles for biomarker detection based on the soluble protein precipitation method described above in example 20. The microvesicle fraction of these samples was subsequently analyzed by LC -MS/MS in an Orbitrap Elite mass spectrometer coupled with a Dionex UltiMate 3000 UHPLC system. A total of 9 of the biomarkers from the list of 20 candidates have been identified in LACI patients (recurrent vascular and cognitive decline) compared to controls (Figure 15). These include GFAP (SEQ ID NO. 46), CKB (SEQ ID NO. 60), PPBP (SEQ ID NO. 105), SYTL4 (SEQ ID NO. 107), APOM (SEQ ID NO. 74), DPYL2 (SEQ ID NO. 45), APP (SEQ ID NO. 74), MBP (SEQ ID NO. 31), and PIF (SEQ ID NO. 47).

Claims

Claims
1. A method for determining the prognosis of a subject afflicted by ischemic
stroke comprising:
a) isolating plasma microvesicles from a plasma sample obtained from the subject; and
b) determining the presence and/or amount of at least one biomarker
associated with the isolated plasma microvesicles;
c) comparing the determined presence and/or amount of said at least one biomarker with a control, wherein a change in the presence and/or amount of the at least one biomarker relative to said control is indicative for said subject having an unfavorable prognosis.
2. The method of claim 1, wherein the unfavorable prognosis is an increased
likelihood for an adverse event selected from the group of developing cognitive impairment, including dementia, and/or recurrent vascular events.
3. The method of claim 1 or 2, wherein the prognosis is a long-term prognosis, preferably a prognosis for a time period of more than 12, more than 24, more than 36, more than 48 or more than 60 months.
4. A method for predicting the risk of a subject developing ischemic stroke
comprising:
a) isolating plasma microvesicles from a plasma sample obtained from the subject; and
b) determining the presence and/or amount of at least one biomarker
associated with the isolated plasma microvesicles;
c) comparing the determined presence and/or amount of said at least one biomarker with a control, wherein a change in the presence and/or amount of the at least one biomarker relative to said control is indicative for an increased risk of said subject developing ischemic stroke.
5. A method for diagnosing ischemic stroke in a subject comprising: a) isolating plasma microvesicles from a plasma sample obtained from the subject; and
b) determining the presence and/or amount of at least one biomarker
associated with the isolated plasma microvesicles;
c) comparing the determined presence and/or amount of said at least one biomarker with a control, wherein a change in the presence and/or amount of the at least one biomarker relative to said control is indicative for said subject having suffered an ischemic stroke.
6. The method of claim 4 or 5, wherein the subject had suffered suspected or confirmed lacunar infarction.
7. The method of any one of claims 1 to 6, wherein the subject is diagnosed with or undergoing a therapy for ischemic cerebral small vessel disease (CVD).
8. The method of any one of claims 1 to 6, wherein the ischemic stroke is selected from the group of lacunar infarction (LACI), transient ischemic attack (TIA) or silent stroke.
9. The method of any one of claims 1 to 6, wherein the control subject is a subject who has not suffered ischemic stroke.
10. The method of any one of claims 1 to 9, wherein the plasma microvesicles include exosomes.
11. The method of any one of claims 1 to 10, wherein the plasma microvesicles are isolated by ultracentrifugation, sucrose density gradient centrifugation, or soluble protein precipitation.
12. The method of any one of claims 1 to 1 1, wherein the amount of the at least one biomarker is determined by a combined chromatography/mass spectrometry technique, preferably LC/MS/MS technique, more preferably iTRAQ (isobaric tags for relative and absolute quantitation).
13. The method of any one of claims 1 to 12, wherein the biomarkers are selected from the group consisting of polypeptides set forth in SEQ ID NOS 1-1 14
14. The method of claim 13, wherein the biomarker is selected from the group consisting of polypeptides set forth in SEQ ID NOS 4, 6, 8, 13, 18, 21, 25, 31, 44-47, 52-74 and an increased level is indicative for an unfavorable prognosis, that said subject has suffered ischemic stroke or has an increased likelihood to suffer ischemic stroke.
The method of claim 13, wherein the biomarker is selected from the group consisting of polypeptides set forth in SEQ ID NOS 12, 19, 27, 28, 48-51, 75- 109 and a decreased level is indicative for an unfavorable prognosis, that said subject has suffered ischemic stroke or has an increased likelihood to suffer ischemic stroke.
The method of claim 13, wherein the biomarker is selected from the group consisting of polypeptides set forth in SEQ ID NOS 31, 44-47 and an increased level is indicative for an unfavorable prognosis, that said subject has suffered ischemic stroke or has an increased likelihood to suffer ischemic stroke.
The method of claim 13, wherein the biomarker is selected from the group consisting of polypeptides set forth in SEQ ID NOS 28, 48-51 and a decreased level is indicative for an unfavorable prognosis, that said subject has suffered ischemic stroke or has an increased likelihood to suffer ischemic stroke.
The method of any one of claims 14 to 17, wherein the method is a method for determining the prognosis of a subject afflicted by lacunar infarction.
A panel of biomarkers for determining the prognosis of a subject afflicted by ischemic stroke, predicting the risk of a subject developing ischemic stroke or diagnosing ischemic stroke in a subject comprising at least one, preferably at least two, more preferably at least 5 markers selected from the group consisting of polypeptides set forth in SEQ ID NOS 1-114.
20. The panel of biomarkers of claim 19, wherein the biomarker is represented by a suitable detection reagent for detection of the biomarker.
21. The panel of biomarkers of claim 19 or 20, wherein the biomarker is selected from the group consisting of polypeptides set forth in SEQ ID NOS 4, 6, 8, 13, 18, 21 , 25, 31, 44-47, 52-74 and an increased level is indicative for an unfavorable prognosis, that said subject has suffered ischemic stroke or has an increased likelihood to suffer ischemic stroke.
22. The panel of biomarkers of claim 19 or 20, wherein the biomarker is selected from the group consisting of polypeptides set forth in SEQ ID NOS 12, 19, 27, 28, 48-51 , 75-109 and a decreased level is indicative for an unfavorable prognosis, that said subject has suffered ischemic stroke or has an increased likelihood to suffer ischemic stroke.
23. Use of the panel of biomarkers of any one of claims 19 to 22, for determining the prognosis of a subject afflicted by ischemic stroke, predicting the risk of a subject developing ischemic stroke or diagnosing ischemic stroke in a subject.
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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012110253A2 (en) * 2011-02-18 2012-08-23 Cavadis B.V. Exosomal biomarkers for cardiovascular events

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012110253A2 (en) * 2011-02-18 2012-08-23 Cavadis B.V. Exosomal biomarkers for cardiovascular events

Non-Patent Citations (8)

* Cited by examiner, † Cited by third party
Title
BARON, M. ET AL.: "Cell -derived microparticles in atherosclerosis: biomarkers and targets for pharmacological modulation?", JOURNAL OF CELLULAR AND MOLECULAR MEDICINE, vol. 16, no. 7, 2012, pages 1365 - 1376 *
CUADRADO, E. ET AL.: "The Proteome of Human Brain After Ischemic Stroke", JOURNAL OF NEUROPATHOLOGY AND EXPERIMENTAL NEUROLOGY, vol. 69, no. 11, 2010, pages 1105 - 1115 *
DATTA, A. ET AL.: "Discovery of Prognostic Biomarker Candidates of Lacunar Infarction by Quantitative Proteomics of Microvesicles Enriched Plasma", PLOS ONE, vol. 9, no. ISSUE, 2014, pages E99663 *
DATTA, A. ET AL.: "Quantitative clinical proteomic study of autopsied human infarcted brain specimens to elucidate the deregulated pathways in ischemic stroke pathology", JOURNAL OF PROTEOMICS, vol. 91, pages 556 - 568 *
JICKLING, G.C. ET AL.: "Blood Biomarkers of Ischemic Stroke", NEUROTHERAPEUTICS, vol. 8, 2011, pages 349 - 360 *
KANHAI, D.A. ET AL.: "Microvesicle protein levels are associated with increased risk for future vascular events and mortality in patients with clinically manifest vascular disease", INTERNATIONAL JOURNAL OF CARDIOLOGY, vol. 168, 26 February 2013 (2013-02-26), pages 2358 - 2263 *
STANKOVIC, S. ET AL.: "Genetic aspects of ischemic stroke: coagulation, homocysteine, and lipoprotein metabolism as potential risk factors", CRITICAL REVIEWS IN CLINICAL LABORATORY SCIENCES, vol. 47, no. 2, 2010, pages 72 - 123 *
WHITELEY, W. ET AL.: "Blood Biomarkers in the Diagnosis of Ischemic Stroke: A Systematic Review", STROKE, vol. 39, 2008, pages 2902 - 2909 *

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