Stroke Biomarkers Research Articles

Identification of Potential Biomarkers for Artificial Cold Exposure–induced Hypertensive Stroke by Proteomic Analysis

The effect of changing temperature on an individual's cerebrovascular risk is both biologically plausible and supported by epidemiologic evidence. We used a global proteomic-based approach to analyze the expression alterations of proteins in artificial cold exposure (ACE)-induced hypertensive stroke in renovascular hypertensive rats (RHR) and to identify the biomarker of ACE-induced hypertensive stroke. The RHR models were established by 2 kidney 2 clip methods. ACE treatment was achieved using an intelligent artificial climate cabinet. Blood pressure and neurologic symptoms were observed before and after ACE treatment. Hemorrhagic condition and infarction survey were examined using 2,3,5-triphenyltetrazolium chloride staining. The total number of proteins derived from the cerebral tissue of the RHR models were analyzed with 2-dimensional gel electrophoresis (2-DE), ImageMaster 2D Platinum software, and mass spectrometry. Significantly regulated proteins selected for further functional studies using the Search Tool for the Retrieval of Interacting Genes/Proteins system were verified by Western blot. ACE-induced stroke in the RHR group (31.25%, 25 of 80 vs. 16.25%, 13 of 80; P < .05) but not in the sham-operated group. Following ACE treatment, we identified 37 differentially expressed proteins and 28 were unique. Two of the upregulated proteins, Syt1 and Idh3a, were obtained by bioinformatics analysis and verified by Western blot. The rate of morbidity as a result of stroke in RHR was obviously elevated after ACE treatment. ACE might affect protein expression profile in cerebral tissues of RHR. Syt1 and Idh3a may play a vital role in ACE-induced hypertensive stroke.

Circulating MicroRNAs as Novel Potential Biomarkers for Early Diagnosis of Acute Stroke in Humans

Many diseases include microRNAs (miRNAs) as reported biomarkers. The significance of circulating miRNAs for early diagnosis of acute stroke in humans is unknown. We aim to determine whether circulating miRNAs potentially serve as novel biomarkers for acute stroke. We prospectively recruited patients with acute stroke and those with nonstroke disease. Patients with acute stroke were identified using magnetic resonance imaging (MRI) for early diagnosis. If the patient suffered from acute stroke that was detected with diffusion-weighted imaging, the patient was defined as an MRI(+) patient. Otherwise, it was defined as an MRI(-) patient. Circulating miRNAs were measured by miRNA microarray and real-time polymerase chain reaction (PCR) analysis. A total of 136 patients were included in the study. Testing by miRNA microarray and real-time PCR analyses showed that hsa-miR-106b-5P and hsa-miR-4306 were present with markedly high abundance in patients of acute stroke, whereas hsa-miR-320e and hsa-miR-320d were present with quite low abundance in patients compared with healthy individuals. Compared with healthy individuals, the miRNAs were increased as in patients with acute stroke as follows: hsa-miR-106b-5P, 3.63-fold in MRI(-) patients and 23.90-fold in MRI(+) patients; hsa-miR-4306, 3.19-fold in MRI(-) patients and 5.30-fold in MRI(+) patients; hsa-miR-320e, .33-fold in MRI(-) patients and .13-fold in MRI(+) patients; and hsa-miR-320d, .23-fold in MRI(-) patients and .07-fold in MRI(+) patients. Elevated hsa-miR-106b-5P and hsa-miR-4306 and decreased hsa-miR-320e and hsa-miR-320d in plasma may be novel biomarkers for the early detection of acute stroke in humans.

Diagnostic Significance of Ischemia-Modified Albumin, S100b, and Neuron-Specific Enolase in Acute Ischemic Stroke

Objective: Use of biochemical markers of cerebral ischemia is a newly favored approach for early diagnosis of ischemic stroke. Our aim was to establish the sensitivity and specificity of ischemia-modified albumin (IMA) in acute ischemic stroke and to compare it with S100b and neuron-specific enolase (NSE). We also intended to investigate the usefulness of a panel composed of these three biomarkers in acute ischemic stroke. Material and Methods: Consecutive adult patients who were admitted to the emergency department with focal neurological deficits were enrolled. Serum samples were obtained at the initial examination, and IMA, S100b, and NSE were measured. Receiver operating characteristics (ROC) curve analysis was used to determine the cut-off values of the biomarker and biomarker groups. Results: Serum IMA, NSE, and S100b levels were significantly higher in ischemic stroke patients (p<0.001, p=0.005, p=0.001, respectively). The optimum diag nostic cutoff point for IMA was 0.31 ABSU with 90% sensitivity and 57% specificity; 18 µg/L for NSE with 61% sensitivity and 53% specificity; and 65 pcg/l for S100b with 87% sensitivity and 72% specificity. With a combination of IMA with either S100b or NSE, instead of IMA alone, the best results were obtained with IMA and S100b, at 97% sensitivity and 37% specificity. Conclusion: This study indicates that IMA was a sensitive diagnostic biomarker in the acute phase of ischemic stroke, although its specificity is low. The combi nation of IMA with S100b and NSE did not add any beneficial effect to the specificity of IMA alone. (JAEM 2014; 13: 112-7)

MiRNA expression profiles in cerebrospinal fluid and blood of patients with acute ischemic stroke.

The aims of the study were (1) to determine whether miRNAs (microRNAs) can be detected in the cerebrospinal fluid (CSF) and blood of patients with ischemic stroke and (2) to compare these miRNA profiles with corresponding profiles from other neurological patients to address whether the miRNA profiles of CSF or blood have potential usefulness as diagnostic biomarkers of ischemic stroke. CSF from patients with acute ischemic stroke (n = 10) and patients with other neurological diseases (n = 10) was collected by lumbar puncture. Blood samples were taken immediately after. Expression profiles in the cell-free fractions of CSF and blood were analyzed by a microarray technique (miRCURY LNA™ microRNA Array, Exiqon A/S, Denmark) using a quantitative PCR (qPCR) platform containing 378 miRNA primers. In total, 183 different miRNAs were detected in the CSF, of which two miRNAs (let-7c and miR-221-3p) were found upregulated in relation to stroke. In the blood, 287 different miRNAs were detected of which two miRNAs (miR-151a-3p and miR-140-5p) were found upregulated and one miRNA (miR-18b-5p) was found downregulated in the stroke group. Some miRNAs occurred exclusively in the CSF including miR-523-3p which was detected in 50% of the stroke patients, whereas it was completely absent in controls. Our preliminary results demonstrate that it is possible to detect and profile miRNAs in CSF and blood from patients with neurological diseases. Some miRNAs appear differentially expressed in the CSF and others in the blood of stroke patients. Currently, we are validating our results in larger groups of patients.

Biochemical and inflammatory biomarkers in ischemic stroke: translational study between humans and two experimental rat models.

Backgroundour objective was to examine the plasma levels of three biological markers involved in cerebral ischemia (IL-6, glutamate and TNF-alpha) in stroke patients and compare them with two different rat models of focal ischemia (embolic stroke model- ES and permanent middle cerebral artery occlusion ligation model-pMCAO) to evaluate which model is most similar to humans. Secondary objectives: 1) to analyze the relationship of these biological markers with the severity, volume and outcome of the brain infarction in humans and the two stroke models; and 2) to study whether the three biomarkers are also increased in response to damage in organs other than the central nervous system, both in humans and in rats.MethodsMulti-center, prospective, case-control study including acute stroke patients (n = 58) and controls (n = 19) with acute non-neurological diseases Main variables: plasma biomarker levels on admission and at 72 h; stroke severity (NIHSS scale) and clinical severity (APACHE II scale); stroke volume; functional status at 3 months (modified Rankin Scale [mRS] and Barthel index [BI]). Experimental groups: ES (n = 10), pMCAO (n = 6) and controls (tissue stress by leg compression) (n = 6). Main variables: plasma biomarker levels at 3 and 72 h; volume of ischemic lesion (H&E) and cell death (TUNEL).Resultsin stroke patients, IL-6 correlated significantly with clinical severity (APACHE II scale), stroke severity (NIHSS scale), infarct volume (cm3) and clinical outcome (mRS) (r = 0.326, 0.497, 0.290 and 0.444 respectively; P < 0.05). Glutamate correlated with stroke severity, but not with outcome, and TNF-alpha levels with infarct volume. In animals, The ES model showed larger infarct volumes (median 58.6% vs. 29%, P < 0.001) and higher inflammatory biomarkers levels than pMCAO, except for serum glutamate levels which were higher in pMCAO. The ES showed correlations between the biomarkers and cell death (r = 0.928 for IL-6; P < 0.001; r = 0.765 for TNF-alpha, P < 0.1; r = 0.783 for Glutamate, P < 0.1) and infarct volume (r = 0.943 for IL-6, P < 0.0001) more similar to humans than pMCAO. IL-6, glutamate and TNF-α levels were not higher in cerebral ischemia than in controls.ConclusionsBoth models, ES and pMCAO, show differences that should be considered when conducting translational studies. IL-6, Glutamate and TNF-α are not specific for cerebral ischemia either in humans or in rats.

Von Willebrand factor drives the association between elevated factor VIII and poor outcomes in patients with ischemic stroke.

Despite clear roles of factor VIII (FVIII) and von Willebrand factor (vWF) in thrombosis, few studies have examined the relationship of these factors with acute ischemic stroke (AIS). We sought to determine whether concurrent elevation in FVIII and vWF was associated with adverse events and outcomes. From our prospective stroke registry, patients consecutively admitted with AIS between July 2008 and October 2013 were included if both FVIII and vWF were measured during admission. The primary outcome was the modified Rankin Scale score on discharge. Among 1453 cases in our stroke registry, 148 patients with AIS met inclusion criteria; 62 patients (41.9%) had FVIII-/vWF-, 16 patients (10.8%) had FVIII+/vWF-, and 51 patients (34.5%) had FVIII+/vWF+. In the fully adjusted model, patients with FVIII+/vWF+ had increased odds of inpatient complications (odds ratio, 8.6; 95% confidence interval, 1.58-46.85; P=0.013) and neuroworsening (odds ratio, 3.2; 95% confidence interval, 1.18-8.73; P=0.022) than patients with FVIII-/vWF-. Adjusted for age, baseline stroke severity, and glucose, patients with FVIII+/vWF+ had increased odds of poor functional outcome (modified Rankin Scale>2; odds ratio, 2.87; 95% confidence interval, 1.16-7.06; P=0.021) than patients with FVIII-/vWF-. Concurrent FVIII/vWF elevation predicts higher odds of inpatient complications, neuroworsening, and worse functional outcomes for patients with AIS compared with patients with normal levels. Our findings suggest that FVIII and vWF levels may serve as clinically useful stroke biomarkers by providing risk profiles for patients with AIS.

Supplementation of folic acid and vitamin B12 reduces plasma levels of asymmetric dimethylarginine in patients with acute ischemic stroke

Increased levels of asymmetric dimethylarginine (ADMA) have been observed in patients with acute ischemic stroke. We aimed to investigate the correlation between ADMA and ischemic stroke, and evaluate the effect of supplementation of folic acid and vitamin B12 on concentrations of ADMA. Patients were randomized into intervention and non-intervention groups within 3days after symptom onset. Intervention group patients were treated with folic acid (5mg daily) and vitamin B12 (500μg twice daily) for 12weeks. ADMA and homocysteine (Hcy) concentrations were measured before treatment (baseline) and 2 and 12weeks after treatment. The laboratory measures were also collected from healthy controls. Eighty five subjects were enrolled in this study, from whom 72 with complete baseline and follow-up laboratory data were included in the present analysis. Thirty four patients were assigned to the intervention group and 38 patients to the non-intervention group. Sixty people were enrolled as healthy controls. Levels of ADMA and Hcy were raised (p<0.05) in patients with acute ischemic stroke. With supplementation of both folic acid and vitamin B12, the levels of ADMA and Hcy decreased significantly at 2 and 12weeks (p<0.05). The present study reconfirmed that ADMA can be regarded as a risk biomarker for acute ischemic stroke. We observed that with supplementation of folic acid and vitamin B12, levels of ADMA were decreased in patients with acute ischemic stroke.

Significance of plasma adiponectin for diagnosis, neurological severity and functional outcome in ischemic stroke — Research for Biomarkers in Ischemic Stroke (REBIOS)

ObjectiveAlthough adiponectin is a major adipocytokine that affects the pathogenesis of various cardiovascular diseases, its clinical significance in stroke remains controversial. We investigated the clinical significance of plasma adiponectin for the diagnosis, neurological severity and functional outcomes of patients with ischemic stroke. MethodsWe prospectively enrolled 171 patients with ischemic stroke and 171 age- and sex-matched healthy controls. Blood samples and clinical information were obtained at day 0, 3, 7, 14 and 90 after stroke onset. ResultsAverage adiponectin values at day 0 did not significantly differ between the controls and the patients, but were significantly lower and higher in patients with atherothrombotic brain (ATBI) (p=0.047) and cardioembolic (CE) (p=0.008) infarction, respectively, than in the controls. Multivariate logistic regression analyses showed that the adiponectin value at day 0 could predict ATBI (odds ratio, 0.75; 95% confidence interval, 0.58 to 0.91, p=0.009, per 1-μg/mL increase). Adiponectin values at day 0 were positively associated with neurological severity as evaluated by the National Institute of Health Stroke Scale upon admission (r=0.420, p=0.003) and were higher in the groups with poor outcomes (modified Rankin Scale (mRS)≥3 on day 90) than in those with good ones (mRS≤2) in all stroke subtypes, with statistical significance in ATBI (p=0.015). ConclusionsPlasma adiponectin values may help to classify stroke subtypes and predict neurological severity and functional outcome in ischemic stroke patients.

Plasma S100A12 is associated with functional outcome after ischemic stroke: Research for Biomarkers in Ischemic Stroke

BackgroundIschemic stroke is accompanied by an inflammatory response, which exacerbates brain injury and deteriorates functional outcome. S100A12 is expressed abundantly in granulocytes, and has been implicated to play an important role on inflammatory reactions in various disease states. We aimed to determine the association between plasma S100A12 levels and a functional outcome in patients with acute ischemic stroke. MethodsWe prospectively included 171 patients with acute ischemic stroke within 24h after onset in this study. Plasma samples were collected for the measurement of S100A12 levels. Poor functional outcome was defined as a modified Rankin Scale of 2–6 at day 90 after stroke onset. ResultsOf 171 patients, 74 (43.3%) had a poor functional outcome at day 90 after stroke onset. Plasma S100A12 levels on admission were significantly higher in patients with a poor functional outcome (2.1 [1.2–5.1] ng/mL, median [interquartile]) than in those with a favorable outcome (1.1 [0.5–2.0] ng/mL; p<0.001). Multivariate analysis showed that the highest quartile of plasma S100A12 levels on admission showed a significantly higher risk for a poor functional outcome (odds ratio, 4.01; 95% confidence interval, 1.09–16.10; p=0.03) than the lowest quartile. ConclusionsHigh plasma S100A12 levels on admission are associated with a poor functional outcome in patients with acute ischemic stroke.

Nascent Proteomes in Peripheral Blood Mononuclear Cells as a Novel Source for Biomarker Discovery in Human Stroke

The proteome of newly synthesized proteins (nascent proteome) in peripheral blood mononuclear cells (PBMCs) can be a novel source of stroke biomarkers. Changes in the PBMC nascent proteome after stroke reflect the dynamic response-in-action not detectable in the total proteome (all existing proteins) in blood. Here, we test the application of nascent proteomics as a novel approach for stroke biomarker discovery. The PBMC nascent proteome in human blood was determined by metabolic labeling of fresh PBMC cultures with azidohomoalanine (an azide-containing methionine surrogate), followed by mass spectrometry detection and quantification of azidohomoalanine-labeled proteins. The PBMC nascent and total proteomes were compared between patients with stroke and matched controls. Both PBMC nascent and total proteomes showed differences between stroke patients and controls. Results of hierarchical clustering analysis of proteomic data revealed greater changes in the nascent than in the total PBMC proteomes, supporting the usefulness of the PBMC nascent proteome as a novel source of stroke biomarkers. Nascent proteomes in PBMC can be a novel source for biomarker discovery in human stroke.

Routine serum C-reactive protein and stroke outcome after intravenous thrombolysis

The clinical usefulness of blood biomarkers in acute stroke is not yet fully established, especially after thrombolytic therapy. Our aim was to investigate the association between routine serum C-reactive protein (CRP) measured within 24h after admission and outcome in ischaemic stroke patients treated with intravenous thrombolysis, adjusting for a history of recent infection. We analysed the data of consecutive stroke patients who received intravenous alteplase in our centre between October 2003 and December 2011, collected in a detailed prospective registry. Routine serum CRP was measured within 24h from admission; concentration >5ng/ml was considered elevated. Serum CRP was measured in 341 of 406 stroke patients treated with alteplase. Patients with elevated CRP (135/341, 42.5%) compared to those with normal CRP values, were significantly older, more frequently presented with a preexisting disability, comorbidities and suffered more severe strokes. They had a higher proportion of symptomatic intracranial haemorrhage according to ECASS II definition (7.2% vs 1.6%, P=0.010), higher 3-month mortality (25.6% vs 11.3%, P=0.001), and were less frequently alive and independent after 3months (45.9% vs 63.7%, P=0.002). However, those associations were not confirmed after adjustment for age, stroke severity, diabetes, congestive heart failure, lack of prestroke disability and signs of recent infection. According to our findings, elevated routine serum CRP measured within 24h after admission does not seem to independently affect the outcome in patients receiving intravenous thrombolysis for stroke. However, further studies of blood samples taken directly before the treatment are needed.

Stroke care in West Bohemia – personalised medicine approach

Cerebrovascular disease is the third main cause of death and the leading cause of disablement in the Czech Republic. The incidence of stroke is higher than in Western European countries and is one of causes of lower average age in this country. The data of 15880 stroke patients who entered into the IKTA stroke register from 13 Czech stroke centres in the year 2010 and 2011 indicates higher proportion of stroke recurrence and unfavourable patient risk profile than in other Western European countries. Three major risk factors well–defined are arterial hypertension (identified in 86.2% of patients), dyslipidemia (58.2%) and diabetes mellitus (34.9% of stroke patients). Three or more risk factors were found in 80.7% of stroke patients. The incidence of vascular risk factors in stroke patients is significantly higher than stated in the literature and this unfavourable risk profile may be the main cause of the high incidence of stroke and its recurrence in Czech Republic. Stroke is a typical heterogeneous entity. In April 2010 the Ministry of Health published a document “Cerebrovascular Care in the Czech Republic, Constitution of Stroke Centres”. 11 Complex Cerebrovascular Centres and 23 Cerebrovascular Centres covering the whole area of the Czech Republic were constituted with intension to admit, diagnose and, if necessary, treat all new stroke patients, who had been formerly treated in the departments of internal medicine of any hospitals in the country. The aim is to provide complex, optimal and personalised care in acute phase of stroke, provide early rehabilitation and provide or propose optimal second prevention. Faculty Hospital Pilsen incorporates a long-term experience with stroke care and is one of two hospitals where patients with ischaemic stroke were first treated with intravenous thrombolysis in our country. The stroke care is coordinated by the Department of Neurology with its Stroke Unit and Stroke Team. The cooperation with neuroradiology, neurosurgery, cardiology, biochemical and immunoanalytic laboratories, pathology, genetics and some other specialities in Faculty Hospital and in Faculty of Medicine in Pilsen of Charles University in Prague is well established as well as the cooperation with Emergency Medical Service. Due to these facts West Bohemia region with 589 thousands of habitants has only one Complex Cerebrovascular Centre and no one or two smaller Cerebrovascular Centres as is usual in other regions. The advantage of this situation is the concentration of all stroke patients into the best equipped facility. Due to this fact stroke patients in West Bohemia are well diagnosed and treated. Exact data (numbers of thrombolytic, neurosurgical therapy, neuroradiological interventions and their proportion to all stroke patients) are presented. Special research project “Study of Variety Stroke Biomarkers in Acute Stroke Patients in the Context of Personalised Medicine“, supported by Czech Ministry of Health is being solved in our centre from the year 2011. Its main goal is to test the effectiveness of variety of stroke biomarkers and implement them into the personalised stroke care. Supported by Ministry of Health, Czech Republic - conceptual development of research organization (Faculty Hospital Pilsen - FNPl, 00669806) and by the project ED2.1.00/03.0076 from European Regional Development Fund.

Current perspectives on the use of intravenous recombinant tissue plasminogen activator (tPA) for treatment of acute ischemic stroke.

In 1995, the NINDS (National Institute of Neurological Disorders and Stroke) tPA (tissue plasminogen activator) Stroke Study Group published the results of a large multicenter clinical trial demonstrating efficacy of intravenous tPA by revealing a 30% relative risk reduction (absolute risk reduction 11%–15%) compared with placebo at 90 days in the likelihood of having minimal or no disability. Since approval in 1996, tPA remains the only drug treatment for acute ischemic stroke approved by the US Food and Drug Administration. Over the years, an abundance of research and clinical data has supported the safe and efficacious use of intravenous tPA in all eligible patients. Despite such supporting data, it remains substantially underutilized. Challenges to the utilization of tPA include narrow eligibility and treatment windows, risk of symptomatic intracerebral hemorrhage, perceived lack of efficacy in certain high-risk subgroups, and a limited pool of neurological and stroke expertise in the community. With recent US census data suggesting annual stroke incidence will more than double by 2050, better education and consensus among both the medical and lay public are necessary to optimize the use of tPA for all eligible stroke patients. Ongoing and future research should continue to improve upon the efficacy of tPA through more rapid stroke diagnosis and treatment, refinement of advanced neuroimaging and stroke biomarkers, and successful demonstration of alternative means of reperfusion.

Abstract W MP39: Basic Fibroblast Growth Factor after Ischemic Stroke in Diabetic Patients - Research for Biomarkers in Ischemic Stroke (REBIOS)

Background: In patients with diabetes mellitus (DM), functional outcome after ischemic stroke is poor. However, the precise mechanisms remain unclear. We hypothesized that basic fibroblast growth factor (bFGF), a neurotrophic/growth factor, does not function after ischemic stroke in DM patients compared with in non-DM ones. Methods and Results: We recruited 171 patients with ischemic stroke from the Fukuoka Stroke Registry, a prospective multi-centered study for acute stroke in Japan, and age- and sex- matched healthy subjects. Blood samples were obtained at five time points after the onset, day 0 (within 24 hours), 3, 7, 14 and 90. Plasma bFGF values were measured by Human MAP® v1.6, a multiplexed immunoassay (Myriad RBM, Inc.). Plasma bFGF was significantly higher in stroke patients at day 0 than in the controls (162.1 ± 21.0 vs. 91.0 ± 8.1 pg/ml, p = 0.001). The concentration of bFGF remained high during 90 days after onset. Unexpectedly, bFGF was significantly higher in patients with DM than in those without DM (180.8 ± 19.5 vs. 127.5 ± 13.1 pg/ml, p = 0.033), while the presence of DM did not associate with bFGF levels in healthy controls. Plasma bFGF was correlated positively with HbA1c ( p = 0.037), causal plasma glucose ( p = 0.048), and ICAM-1 ( p = 0.032) / VCAM-1 ( p = 0.086), representative adhesion molecules expressed in endothelial cells. In a mouse middle cerebral artery occlusion (MCAO) stroke model, bFGF expression in streptpzotocin-induced diabetic mice was significantly greater in ischemic hemisphere than in contralateral hemisphere. Immunohistochemical examination demonstrated that bFGF was expressed highly in vWF + endothelial cells, desmin + pericytes, and MAP2 + neurons, in peri-infarct areas after MCAO. Conclusion: Plasma bFGF was increased after ischemic stroke, which was prominent in DM patients. The presence of hyperglycemia in acute ischemic stroke may affect the expression of bFGF in various cell types in peri-infarct areas, which in turn may be associated with endothelial function, including the expression of adhesion molecules.

Abstract W P143: Race-specific Effects of Inflammatory and Vascular Remodeling Biomarkers in Ischemic Stroke

Background: Blacks have a higher risk of stroke than whites; inflammatory and vascular remodeling (VR) biomarkers may mediate this risk. We aimed to determine associations between inflammatory and VR biomarkers and ischemic stroke in a bi-racial sample of the Atherosclerosis Risk In Communities (ARIC) cohort. Methods: In a case-control pilot study, 133 participants from Forsyth and Jackson Field Centers were identified: 32 blacks and 33 whites with first ischemic stroke after visit 2, and 33 black and 35 white stroke-free controls. We assayed IL-8, IL-10, IL-1 receptor antagonist (IL-1ra), IL-1β, matrix metalloproteinase-9 (MMP-9), and tissue inhibitor of metalloproteinase-1 (TIMP-1) with Quantikine ELISA. We calculated IL-1β/IL-1ra ratio, representing the IL-1 pathway. Biomarkers were covariates in race-specific logistic regression models; if significant, biomarker-by-race interactions were explored. Results: Cases were older (mean age 60y vs 56y; p&lt;0.0001); more had hypertension (52% vs 35%; p=0.043), and diabetes (35% vs 13%; p=0.0034). There were no differences in biomarkers between blacks and whites (cases and controls). In blacks, there was a trend toward a reduced risk of stroke with increasing levels of IL-1ra after adjustment (p=0.074). In whites, stroke was associated with higher levels of TIMP-1 (p=0.011; interaction p=0.079) and with higher levels of IL-8 (p=0.011; interaction p=0.11) in the unadjusted, but not adjusted model (Table). Conclusion: We identified race-specific associations between biomarkers and incident stroke. VR biomarkers (TIMP-1) may be associated with stroke in whites, and there was a trend towards lower levels of IL-1ra (counter-inflammatory) and risk of stroke in blacks. Larger studies are warranted to confirm these findings and determine if these markers will explain differences in stroke risk in blacks vs whites.

Abstract T P32: Computer Aided Detection of Asymptomatic Cerebral Microbleeds on Magnetic Resonance Images

Purpose: Manual rating of Cerebral microbleeds (CMBs) is time-consuming and inconsistent. Since the presence and number of CMBs have become a potential diagnostic and prognostic biomarker of stroke, an automatic identification method is required. We proposed a computer aided diagnosis (CAD) system for the detection of the CMBs on the magnetic resonance (MR) images automatically. Methods: Eighty-one patients were recruited in this study. CMBs on the MR T2* weighted images were manually rated according to the Microbleed Anatomic Rating Scale (MARS) criteria. Our automated method consisted of two steps: i) Pre-processing: After skull stripping, isolated islands of points were removed while holes were restored to avoid over segmentation. Local threshold segmentation was applied for the initial candidate selection. ii) Identification model: Seven features were extracted from each candidate: area, roundness, intensity, average of the boundary, contrast, shape-intensity and location-mark (according to the probability density templates calculated from the location information of the CMBs). For further identification of each candidate, Random Forest (RF) model was used to distinguish CMBs from the mimics. Results: A total of 337 CMBs in the 81 patients were studied. Comparing with the counting from the experienced doctors, high sensitivity of 92% (310/337) was achieved after pre-processing. The RF model eliminated most of the false-positives while maintaining a reliable sensitivity of 94% (291/310) and specificity of 96% (4272/4450). The area under the Receiver operating characteristic curve was 0.98 ± 0.02 for the detection model. In summary, this CAD system had an overall sensitivity of 86% (291/337) and specificity of 96% (4272/4450), producing only 2.2 false-positives per subject. Conclusion: This presented strategy is technically effective. The results indicate that it has the potential to be used for clinical detection of CMBs.

Pathophysiology and Biomarkers in Acute Ischemic Stroke – A Review

Stroke is one of the major causes of death and disability, including ischemic stroke, which accounts for 85 - 87 % of cases. Currently, there are few treatment options available for minimizing tissue death following a stroke. Emerging data suggest that biomarkers may help improve current clinical outcome of stroke. As such, there is a pressing need to understand the pathophysiology and to explore effective biomarkers following an ischemic brain event. The pathophysiology of ischemic stroke is complex, and majorly involves excitotoxicity, oxidative stress, inflammation, blood-brain barrier dysfunction, apoptosis, etc. Several of the biomarkers are related to these pathophysiologic mechanisms and they may have applications in stroke prediction, diagnosis, assessment, prognosis or treatment. In this review, we summarized the pathophysiology of ischemic stroke and some related biomarkers are examined.

Circulating MicroRNAs as Biomarkers of Acute Stroke

MicroRNAs have been identified as key regulators of gene expression and thus their potential in disease diagnostics, prognosis and therapy is being actively pursued. Deregulation of microRNAs in cerebral pathogenesis has been reported to a limited extent in both animal models and human. Due to the complexity of the pathology, identifying stroke specific microRNAs has been a challenge. This study shows that microRNA profiles reflect not only the temporal progression of stroke but also the specific etiologies. A panel of 32 microRNAs, which could differentiate stroke etiologies during acute phase was identified and verified using a customized TaqMan Low Density Array (TLDA). Furthermore we also found 5 microRNAs, miR-125b-2*, -27a*, -422a, -488 and -627 to be consistently altered in acute stroke irrespective of age or severity or confounding metabolic complications. Differential expression of these 5 microRNAs was also observed in rat stroke models. Hence, their specificity to the stroke pathology emphasizes the possibility of developing these microRNAs into accurate and useful tools for diagnosis of stroke.

Risk factors and biomarkers of ischemic stroke in cancer patients.

Background and PurposeStroke is common among cancer patients. However, risk factors and biomarkers of stroke in cancer patients are not well established. This study aimed to investigate risk factors and biomarkers as well as etiology of ischemic stroke in cancer patients.MethodsA retrospective review was conducted in cancer patients with ischemic stroke who were admitted to a general hospital in Busan, Korea, between January 2003 and December 2012. The risk factors and biomarkers for stroke and stroke subtypes in cancer patients were compared with age- and sex-matched noncancer patients with ischemic stroke who were admitted to the same hospital during the same period.ResultsOne hundred fifty-six cancer patients with ischemic stroke were identified. Cancer patients with ischemic stroke were found to have a significantly lower proportion of hypertension, atrial fibrillation, hyperlipidemia, and ischemic heart disease than noncancer patients with ischemic stroke. However, stroke biomarkers, such as erythrocyte sedimentation rate and high-sensitivity C-reactive protein, fibrinogen, pro-brain natriuretic peptide, and D-dimer levels, were significantly increased in cancer patients with ischemic stroke than in noncancer patients. Large-artery atherosclerosis and stroke of undetermined cause were more common in cancer patients with ischemic stroke than in noncancer patients with ischemic stroke.ConclusionsCancer patients with ischemic stroke showed different risk factors, stroke biomarkers, and stroke etiology compared with noncancer patients with ischemic stroke.

Correlative study of serum cystatin C levels with severity of acute ischemic stroke.

Background: The attractiveness of cystatin C as a biomarker for acute ischemic stroke is obvious, in the background of accumulating evidence indicating a link between vascular disease of the kidney and brain. We investigated the association of serum cystatin C levels with first onset acute ischemic stroke and the correlation of serum cystatin C levels with severity of acute ischemic stroke as assessed by NIH stroke scale. Methods: A total of 50 patients with first onset of acute ischemic stroke, aged more than 45 years, presenting within 72 hours after onset, by interview, history, clinical examination, neuroimaging and other investigations. Serum Cystatin C was measured by means of a particle-enhanced immunenephelometric assay (N Latex Cystatin C) with a nephelometer (Siemens BN Prospec). Results: Serum cystatin C levels were significantly raised in 62% (n=31) patients of acute ischemic stroke compared with controls 14% (n=7), with a p < 0.001. Compared with controls, the mean serum cystatin C level was significantly higher in stroke patients (1.33±0.71 versus 0.83±0.24 mg / L, p < 0.001). The diagnostic accuracy of serum cystatin C as a marker of acute ischemic stroke evaluated using Receiver Operating Characteristic (ROC) curve analysis, showed a sensitivity of 66.00 and specificity of 84.00 with an area under curve of 0.80 (and 95 % CI (0.71 - 0.87)). Conclusion: Serum cystatin C was a better marker for acute ischemic stroke and indicator of severe neurological impairment. Key words: Acute ischemic stroke, Cystatin C, NIH Stroke scale.