CCL23: A Chemokine Associated with Progression from Mild Cognitive Impairment to Alzheimer's Disease

CCL23 is a chemokine implicated in inflammation and host defense responses. It has been recently associated with acquired brain damage and stroke outcomes. In this study, we reported the role of CCL23 in Alzheimer's disease (AD). We evaluated the levels of CCL23 in 659 individuals: cognitively normal, mild cognitive impaired (MCI), and AD patients. Two cross-sectional (study 1, n = 53; study 2, n = 200) and two longitudinal (study 3, n = 74; study 4, n = 332) studies were analyzed separately. CCL23 levels in the blood and/or cerebrospinal fluid (CSF) of each study were measured by immunoassays. Globally, our results suggest a predictive role of CCL23 protein levels both in the plasma in study 3 (hazard ratio (HR) = 2.5 (confidence interval (CI) 95% : 1.2-5.3), p = 0.02) and in the CSF in study 4 (HR = 3.05 (CI 95% : 1.02-5), p = 0.04) in cases of MCI that progress to AD. Moreover, we observed that the APOEɛ4 allele was associated with higher levels of CCL23 in study 2 (470.33 pg/mL (interquartile range (IQR): 303.33-597.76) versus 377.94 pg/mL (IQR: 267.16-529.19), p = 0.01) (APOE genotypes were available in studies 2 and 4). Together, these findings support the role of CCL23 in neuroinflammation in the early stages of AD, suggesting that CCL23 might be a candidate blood biomarker for MCI to AD progression.

Changes in Body Fat Distribution in Antiretroviral-Naive HIV-Positive Individuals Initiating Current ART Regimens

OBJECTIVES

To describe the changes in body fat distribution (BFD) occurring over 60 months in a group of antiretroviral therapy (ART)-naive individuals starting different antiretroviral regimens.

METHODS

A prospective ongoing fat change assessment including clinical evaluation and dual X-ray absorptiometry scan is being conducted in all consecutive patients initiating ART from January 2008. Arm, leg, trunk, and total fat as well as fat mass ratio were determined.

RESULTS

A total of 146 patients were included (80% male, 40% MSM). Mean age was 44 years, HIV-1 RNA was 4.98 log10 copies/mL, and CD4 count was 254 cells/μL. The most common initial antiretroviral combination included non-nucleoside reverse transcription inhibitor (NNRTI) drugs followed by protease inhibitor (PI) and integrase strand transfer inhibitor (INSTI)-based regimens. At month 36, an increase was seen in the body mass index (BMI), total fat, trunk fat, and limb fat. The fat mass ratio (FMR) also showed a significant increase in both men and women (P = 0.001). In patients receiving NNRTI- or INSTI-based regimens (but not PIs), there was a marginal but statistically significant increase in the FMR (0.10 and 0.07, respectively; P = 0.01). Sixty-two subjects completed 60 months of follow-up. FMR showed a significant increase even in the PI group at this time point (P < 0.03).

CONCLUSIONS

We observed a significant increase in the fat and lean body mass in all compartments and treatment groups over 36 and 60 months. Clinically irrelevant differences were found in fat distribution regardless of the treatment group and baseline characteristics. The data suggest that current antiretroviral regimens have little impact on BFD during the first years of treatment.

Importance of Angiogenin and Endothelial Progenitor Cells After Rehabilitation Both in Ischemic Stroke Patients and in a Mouse Model of Cerebral Ischemia

Background: Rehabilitation therapy is the only available treatment for stroke survivors presenting neurological deficits; however, the underlying molecules and mechanisms associated with functional/motor improvement during rehabilitation are poorly understood. Objective: Our aim is to study the modulation of angiogenin and endothelial progenitor cells (EPCs) as repair-associated factors in a cohort of stroke patients and mouse models of rehabilitation after cerebral ischemia. Methods: The clinical study included 18 ischemic strokes admitted to an intensive rehabilitation therapy (IRT) unit, 18 non-ischemic controls and brain samples from three deceased patients. Angiogenin and EPCs were measured in blood obtained before and up to 6 months after IRT together with an extensive evaluation of the motor/functional status. In parallel, C57BL/6 mice underwent middle cerebral artery occlusion, and the pasta matrix reaching-task or treadmill exercises were used as rehabilitation models. Angiogenin RNA expression was measured after 2 or 12 days of treatment together with cell counts from EPCs cultures. Results: Brain angiogenin was identified in both human and mouse tissue, whereas serum levels increased after 1 month of IRT in association with motor/functional improvement. EPC populations were increased after stroke and remained elevated during follow-up after IRT. The mouse model of rehabilitation by the task-specific pasta matrix exercise increased the number of EPCs at 2 days and increased angiogenin expression after 12 days of rehabilitation. Conclusions: Angiogenin and EPCs are modulated by rehabilitation after cerebral ischemia, suggesting that both angiogenin and EPCs could serve as biomarkers of improvement during rehabilitation or future therapeutic targets.

Characterization of the rat cerebrospinal fluid proteome following acute cerebral ischemia using an aptamer-based proteomic technology

The limited accessibility to the brain has turned the cerebrospinal fluid (CSF) into a valuable source that may contribute to the complete understanding of the stroke pathophysiology. Here we have described the CSF proteome in the hyper-acute phase of cerebral ischemia by performing an aptamer-based proteomic assay (SOMAscan) in CSF samples collected before and 30 min after male Wistar rats had undergone a 90 min Middle Cerebral Artery Occlusion (MCAO) or sham-surgery. Proteomic results indicated that cerebral ischemia acutely increased the CSF levels of 716 proteins, mostly overrepresented in leukocyte chemotaxis and neuronal death processes. Seven promising candidates were further evaluated in rat plasma and brain (CKB, CaMK2A, CaMK2B, CaMK2D, PDXP, AREG, CMPK). The 3 CaMK2 family-members and CMPK early decreased in the infarcted brain area and, together with AREG, co-localized with neurons. Conversely, CKB levels remained consistent after the insult and specifically matched with astrocytes. Further exploration of these candidates in human plasma revealed the potential of CKB and CMPK to diagnose stroke, while CaMK2B and CMPK resulted feasible biomarkers of functional stroke outcome. Our findings provided insights into the CSF proteome following cerebral ischemia and identified new outstanding proteins that might be further considered as potential biomarkers of stroke.

CCL23: a new CC chemokine involved in human brain damage

BACKGROUND

CCL23 role in the inflammatory response after acute brain injuries remains elusive. Here, we evaluated whether CCL23 blood levels associate with acquired cerebral lesions and determined CCL23 predictive capacity for assessing stroke prognosis. We used preclinical models to study the CCL23 homologous chemokines in rodents, CCL9 and CCL6.

METHODS

Baseline CCL23 blood levels were determined on 245 individuals, including ischaemic strokes (IS), stroke mimics and controls. Temporal profile of circulating CCL23 was explored from baseline to 24 h in 20 of the IS. In an independent cohort of 120 IS with a 3-month follow-up, CCL23 blood levels were included in logistic regression models to predict IS outcome. CCL9/CCL6 cerebral expression was evaluated in rodent models of brain damage. Both chemokines were also profiled in circulation and histologically located on brain following ischaemia.

RESULTS

Baseline CCL23 blood levels did not discriminate IS, but permitted an accurate discrimination of patients presenting acute brain lesions (P = 0.003). IS exhibited a continuous increase from baseline to 24 h in circulating CCL23 (P < 0.001). Baseline CCL23 blood levels resulted an independent predictor of IS outcome at hospital discharge (OR_adj : 19.702 [1.815-213.918], P = 0.014) and mortality after 3 months (OR_adj : 21.47 [3.434-134.221], P = 0.001). In preclinics, expression of rodent chemokines in neurons following cerebral lesions was elevated. CCL9 circulating levels decreased early after ischaemia (P < 0.001), whereas CCL6 did not alter within the first 24 h after ischaemia.

CONCLUSIONS

Although preclinical models do not seem suitable to characterize CCL23, it might be a novel promising biomarker for the early diagnosis of cerebral lesions and might facilitate the prediction of stroke patient outcome.

Sepsis biomarkers reprofiling to predict stroke-associated infections

We aimed to evaluate the usefulness of sepsis biomarkers to predict stroke-associated infections. Soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), mid-regional pro-adrenomedullin (MR-proADM), presepsin (sCD14), and soluble urokinase-type plasminogen activator receptor (suPAR), were explored in 125 blood samples collected at different time-points. At baseline, MR-proADM was an independent predictor of infection [>0.94pg/mL, OR=3.63 (1.16-11.33), p=0.026], as well as suPAR at 24h [>2185.8pg/mL, OR=5.81 (1.05-32.26), p=0.044]. Both MR-proADM and suPAR were raised in patients with infections throughout the first week after stroke. These results are especially relevant for MR-proADM given its early elevation, which would allow early preventive interventions.

Blood Biomarkers for the Early Diagnosis of Stroke: The Stroke-Chip Study

BACKGROUND AND PURPOSE

Stroke diagnosis could be challenging in the acute phase. We aimed to develop a blood-based diagnostic tool to differentiate between real strokes and stroke mimics and between ischemic and hemorrhagic strokes in the hyperacute phase.

METHODS

The Stroke-Chip was a prospective, observational, multicenter study, conducted at 6 Stroke Centers in Catalonia. Consecutive patients with suspected stroke were enrolled within the first 6 hours after symptom onset, and blood samples were drawn immediately after admission. A 21-biomarker panel selected among previous results and from the literature was measured by immunoassays. Outcomes were differentiation between real strokes and stroke mimics and between ischemic and hemorrhagic strokes. Predictive models were developed by combining biomarkers and clinical variables in logistic regression models. Accuracy was evaluated with receiver operating characteristic curves.

RESULTS

From August 2012 to December 2013, 1308 patients were included (71.9% ischemic, 14.8% stroke mimics, and 13.3% hemorrhagic). For stroke versus stroke mimics comparison, no biomarker resulted included in the logistic regression model, but it was only integrated by clinical variables, with a predictive accuracy of 80.8%. For ischemic versus hemorrhagic strokes comparison, NT-proBNP (N-Terminal Pro-B-Type Natriuretic Peptide) >4.9 (odds ratio, 2.40; 95% confidence interval, 1.55-3.71; P<0.0001) and endostatin >4.7 (odds ratio, 2.02; 95% confidence interval, 1.19-3.45; P=0.010), together with age, sex, blood pressure, stroke severity, atrial fibrillation, and hypertension, were included in the model. Predictive accuracy was 80.6%.

CONCLUSIONS

The studied biomarkers were not sufficient for an accurate differential diagnosis of stroke in the hyperacute setting. Additional discovery of new biomarkers and improvement on laboratory techniques seem necessary for achieving a molecular diagnosis of stroke.

GRECOS Project (Genotyping Recurrence Risk of Stroke): The Use of Genetics to Predict the Vascular Recurrence After Stroke

BACKGROUND AND PURPOSE

Vascular recurrence occurs in 11% of patients during the first year after ischemic stroke (IS) or transient ischemic attack. Clinical scores do not predict the whole vascular recurrence risk; therefore, we aimed to find genetic variants associated with recurrence that might improve the clinical predictive models in IS.

METHODS

We analyzed 256 polymorphisms from 115 candidate genes in 3 patient cohorts comprising 4482 IS or transient ischemic attack patients. The discovery cohort was prospectively recruited and included 1494 patients, 6.2% of them developed a new IS during the first year of follow-up. Replication analysis was performed in 2988 patients using SNPlex or HumanOmni1-Quad technology. We generated a predictive model using Cox regression (GRECOS score [Genotyping Reurrence Risk of Stroke]) and generated risk groups using a classification tree method.

RESULTS

The analyses revealed that rs1800801 in the MGP gene (hazard ratio, 1.33; P=9×10^-03), a gene related to artery calcification, was associated with new IS during the first year of follow-up. This polymorphism was replicated in a Spanish cohort (n=1.305); however, it was not significantly associated in a North American cohort (n=1.683). The GRECOS score predicted new IS (P=3.2×10^-09) and could classify patients, from low risk of stroke recurrence (1.9%) to high risk (12.6%). Moreover, the addition of genetic risk factors to the GRECOS score improves the prediction compared with previous Stroke Prognosis Instrument-II score (P=0.03).

CONCLUSIONS

The use of genetics could be useful to estimate vascular recurrence risk after IS. Genetic variability in the MGP gene was associated with vascular recurrence in the Spanish population.

C-reactive protein in the detection of post-stroke infections: systematic review and individual participant data analysis

We conducted a systematic review and individual participant data meta-analysis to explore the role of C-reactive protein (CRP) in early detection or prediction of post-stroke infections. CRP, an acute-phase reactant binds to the phosphocholine expressed on the surface of dead or dying cells and some bacteria, thereby activating complement and promoting phagocytosis by macrophages. We searched PubMed up to May-2015 for studies measuring CRP in stroke and evaluating post-stroke infections. Individual participants' data were merged into a single database. CRP levels were standardized and divided into quartiles. Factors independently associated with post-stroke infections were determined by logistic regression analysis and the additional predictive value of CRP was assessed by comparing areas under receiver operating characteristic curves and integrated discrimination improvement index. Data from seven studies including 699 patients were obtained. Standardized CRP levels were higher in patients with post-stroke infections beyond 24 h. Standardized CRP levels in the fourth quartile were independently associated with infection in two different logistic regression models, model 1 [stroke severity and dysphagia, odds ratio = 9.70 (3.10-30.41)] and model 2 [age, sex, and stroke severity, odds ratio = 3.21 (1.93-5.32)]. Addition of CRP improved discrimination in both models [integrated discrimination improvement = 9.83% (0.89-18.77) and 5.31% (2.83-7.79), respectively], but accuracy was only improved for model 1 (area under the curve 0.806-0.874, p = 0.036). In this study, CRP was independently associated with development of post-stroke infections, with the optimal time-window for measurement at 24-48 h. However, its additional predictive value is moderate over clinical information. Combination with other biomarkers in a panel seems a promising strategy for future studies.

The impact of post-stroke complications on in-hospital mortality depends on stroke severity

INTRODUCTION

Controversies remain on whether post-stroke complications represent an independent predictor of poor outcome or just a reflection of stroke severity. We aimed to identify which post-stroke complications have the highest impact on in-hospital mortality by using machine learning techniques. Secondary aim was identification of patient's subgroups in which complications have the highest impact.

PATIENTS AND METHODS

Registro Nacional de Ictus de la Sociedad Española de Neurología is a stroke registry from 42 centers from the Spanish Neurological Society. Data from ischemic stroke patients were used to build a random forest by combining 500 classification and regression trees, to weight up the impact of baseline characteristics and post-stroke complications on in-hospital mortality. With the selected variables, a logistic regression analysis was performed to test for interactions.

RESULTS

12,227 ischemic stroke patients were included. In-hospital mortality was 5.9% and median hospital stay was 7(4-10) days. Stroke severity [National Institutes of Health Stroke Scale > 10, OR = 5.54(4.55-6.99)], brain edema [OR = 18.93(14.65-24.46)], respiratory infections [OR = 3.67(3.02-4.45)] and age [OR = 2.50(2.07-3.03) for >77 years] had the highest impact on in-hospital mortality in random forest, being independently associated with in-hospital mortality. Complications have higher odds ratios in patients with baseline National Institutes of Health Stroke Scale <10.

DISCUSSION

Our study identified brain edema and respiratory infections as independent predictors of in-hospital mortality, rather than just markers of more severe strokes. Moreover, its impact was higher in less severe strokes, despite lower frequency.

CONCLUSION

Brain edema and respiratory infections were the complications with a greater impact on in-hospital mortality, with the highest impact in patients with mild strokes. Further efforts on the prediction of these complications could improve stroke outcome.

Blood markers of inflammation and endothelial dysfunction in cardioembolic stroke: systematic review and meta-analysis

CONTEXT

Various processes including inflammation and endothelial dysfunction have been implicated in the pathogenesis of cardioembolic (CE) strokes.

OBJECTIVE

To review the evidence and investigate the association between immune-inflammatory biomarkers and CE strokes versus other stroke subtypes.

METHODS

We systematically reviewed the literature (sources: MEDLINE, web-based register http://stroke-biomarkers.com , reference lists) with quality assessment and meta-analysis of selected articles.

RESULTS

The most consistent association was found between C-reactive protein (CRP) and CE strokes when compared to other stroke subtypes (standardized mean difference 0.223 (0.116, 0.343); p < 0.001) Conclusions: Our findings confirm a possible association between selected inflammatory biomarkers and CE stroke.

Abstract 42: Blood Biomarkers Refect Tissue Viability in Acute Ischemic Stroke

Introduction: Assessment of tissue viability, usually performed by multimodal neuroimaging, allows the use of reperfusion therapies in selected patients, even out of the therapeutic time-window. However, multimodal imaging is still a scarce and expensive tool. The availability of blood biomarkers reflecting tissue viability could be a useful tool to manage reperfusion therapies. We aimed to test whether selected candidate biomarkers may reflect tissue viability in relation to Alberta Stroke Program Early CT score (ASPECTS) and multimodal imaging.

Methods: The StrokeChip was a prospective, observational study, conducted at six Hospitals in Catalonia. Patients with suspected stroke were enrolled at Emergency Departments. Blood samples were obtained within the first six hours after symptoms onset to measure a 21-biomarker panel. Acute brain neuroimaging was dichotomized into normal (ASPECTS=10) or pathological (ASPECTS<10). For those patients with perfusion imaging, comparison was performed between patients with and without significant mismatch (>20%).

Results: From August-2012 to December-2013, 941 out of 1308 patients were ischemic strokes. ASPECTS was obtained in admission neuroimaging in 927 patients. Among them, 25% displayed pathological neuroimaging. Levels of Apo-CIII disclosed a positive correlation with ASPECTS, while negative correlations were found for D-dimer, IL-6, GroA, NT-proBNP and IGFBP-3. In logistic regression analysis, Apo-CIII [OR=0.52(0.36-0.75)], D-dimer [OR=2.47(1.39-4.39)] and IGFBP-3 [OR=2.28(1.51-3.43)] were independently associated with ASPECTS <10, after adjustment by age, sex and NIHSS. Moreover, in 103 patients with baseline perfusion imaging (70% with mismatch >20%), Apo-CIII was an independent predictor of the presence of mismatch after adjustment by age, sex and NIHSS [OR=0.27(0.10-0.75)].

Conclusions: Assessment of tissue viability with blood biomarkers seems feasible. Apo-CIII might represent a surrogate marker for tissue viability assessment.

Abstract 67: Blood Biomarkers for Prediction of Cardiac Complications in the Stroke Unit

Introduction: Cardiac complications such as acute coronary syndrome (ACS) or acute congestive heart failure (ACHF) account for 2-6%of mortality after stroke. Early detection of the patients at the highest risk to suffer from cardiac complications could be of interest to indicate a closer monitoring or therapeutic measures. We aimed to test whether a panel of blood biomarkers could predict the development of cardiac complications during stroke unit admission.

Methods: The StrokeChip was a prospective, observational study, conducted at six Hospitals in Catalonia. Patients with suspected stroke were enrolled at Emergency Departments. Blood samples were obtained within the first six hours after symptom onset to measure a 21-biomarker panel. In-hospital development of cardiac complications (ACS and ACHF) was recorded. The association between the measured biomarkers and the development of complications was assessed by logistic regression analysis.

Results: From August-2012 to December-2013, 941 out of 1308 patients enrolled were ischemic strokes. Cardiac complications were developed by 25 patients, including 19 ACHF and six cases of ACS. Due to the small number of ACS, just ACHF were further analyzed. Patients with ACHF had higher baseline levels of D-dimer, endostatin, VAP-1, NT-proBNP, FasL and vWF, and lower levels of IGFBP-3. After logistic regression analysis, NT-proBNP [OR=3.56(1.17-10.84)], FasL [OR=4.94(1.60-15.26)], VAP-1 [OR=6.56(2.21-19.46)] and IGFBP-3 [OR=0.21(0.07-0.67)] were independently associated with ACHF after adjustment by clinical predictors such as stroke severity, previous disability or history of coronary disease. Addition of the biomarker panel over clinical predictors resulted in improved accuracy (AUC from 0.808 to 0.925, p=0.05).

Conclusions: Baseline measurement of blood biomarkers in acute stroke could be useful to predict the development of cardiac complications during stroke unit admission.

Combination of Thrombolysis and Statins in Acute Stroke Is Safe: Results of the STARS Randomized Trial (Stroke Treatment With Acute Reperfusion and Simvastatin)

BACKGROUND AND PURPOSE

The STARS trial (Stroke Treatment With Acute Reperfusion and Simvastatin) was conducted to demonstrate the efficacy and safety of simvastatin treatment in acute stroke.

METHODS

STARS07 was a multicentre, phase IV, prospective, randomized, double-blind, placebo-controlled trial. Patients with Acute ischemic stroke recruited within 12 hours from symptom onset were randomized to oral simvastatin 40 mg or placebo, once daily for 90 days. Primary outcome was proportion of independent patients (modified Rankin Scale score of ≤2) at 90 days. Safety end points were hemorrhagic transformation, hemorrhagic events, death, infections, and serious adverse events.

RESULTS

From April 2009 to March 2014, 104 patients were included. Fifty-five patients received intravenous tissue-type plasminogen activator. No differences were found between treatment arms regarding the primary outcome (adjusted odds ratio, 0.99 [0.35-2.78]; P=0.98). Concerning safety, no significant differences were found in the rate of hemorrhagic transformation of any type, nor symptomatic hemorrhagic transformation. There were no differences in other predefined safety outcomes. In post hoc analyses, for patients receiving tissue-type plasminogen activator, a favorable effect for simvastatin treatment was noted with higher proportion of patients experiencing major neurological recovery (adjusted odds ratio, 4.14 [1.18-14.4]; P=0.02).

CONCLUSIONS

Simvastatin plus tissue-type plasminogen activator combination seems safe in acute stroke, with low rates of bleeding complications. Because of the low recruitment, the STARS trial was underpowered to detect differences in simvastatin efficacy.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01073007.

Circulating cell-free DNA is a predictor of short-term neurological outcome in stroke patients treated with intravenous thrombolysis

Circulating cell-free DNA (cfDNA) has been described as a prognostic marker for several diseases. Its prognostic value for short-term outcome in stroke patients treated with intravenous thrombolysis remains unexplored. cfDNA was measured on admission in 54 tissue plasminogen activator (tPA)-treated patients and 15 healthy controls using a real-time quantitative polymerase chain reaction assay. Neurological outcome was assessed at 48 h. Predictors of neurological improvement were evaluated by logistic regression analysis, and the additional predictive value of cfDNA over clinical variables was determined by integrated discrimination improvement (IDI). Stroke patients presented higher baseline cfDNA than healthy controls (408.5 (179-700.5) vs. 153.5 (66.9-700.5) kilogenome-equivalents/L, p = 0.123). A trend towards lower cfDNA levels was found in patients who neurologically improved at 48 h (269.5 (143.3-680) vs. 504 (345.9-792.3) kilogenome-equivalents/L, p = 0.130). In logistic regression analysis, recanalization at 1 h and cfDNA < 302.75 kilogenome-equivalents/L was independently associated with neurological improvement after adjustment by age, gender and baseline National Institutes of Health Stroke Scale score. The addition of cfDNA to the clinical predictive model improved its discrimination (IDI = 21.2% (9.2-33.3%), p = 0.009). These data suggest that cfDNA could be a surrogate marker for monitoring tPA efficacy by the prediction of short-term neurological outcome.

Plasma Matrix Metalloproteinases in Patients With Stroke During Intensive Rehabilitation Therapy

OBJECTIVE

To study plasma levels of matrix metalloproteinases (MMPs) as potential markers of recovery during intensive rehabilitation therapy (IRT) after stroke.

DESIGN

Prospective and descriptive 3-month follow-up study.

SETTING

Rehabilitation unit and research center.

PARTICIPANTS

Patients with first-ever ischemic stroke (n=15) enrolled to IRT (≥3h/d and 5d/wk) and healthy volunteers (n=15) (N=30).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The primary outcome was to measure plasma MMP3, MMP12, and MMP13 levels and evaluate potential associations with motor/functional scales using a battery of tests (National Institutes of Health Stroke Scale, modified Rankin scale, Barthel Index, Fugl-Meyer Assessment, Functional Ambulation Categories, Medical Research Council scale, Chedoke Arm and Hand Activity Inventory, and the 10-m walk test) before IRT and at 1- and 3-month follow-ups. The secondary outcome was to evaluate the use of these MMPs as biomarkers as predictors of patient's outcome.

RESULTS

MMP levels remained stable during the study period and were similar to those in the healthy volunteer group. However, baseline MMP12 and MMP13 levels were strongly associated with stroke severity and were found to be elevated in those patients with the poorest outcomes. Interestingly, plasma MMP3 was independent of baseline stroke characteristics but was found to be increased in patients with better motor/functional recovery and in patients with larger improvements during rehabilitation.

CONCLUSIONS

MMPs might act as biologic markers of recovery during rehabilitation therapy related to their roles in both injury and tissue remodeling. Future confirmatory investigations in multicenter studies are warranted by our data.

Factor seven activating protease (FSAP) predicts response to intravenous thrombolysis in acute ischemic stroke

BACKGROUND

Prediction of recanalization after intravenous thrombolysis could be important to direct secondary reperfusion techniques. Factor seven activating protease (FSAP) has been described to have a relevant pathophysiological role in stroke.

AIM

The aim is to determine whether plasma FSAP levels are associated with recanalization after tissue plasminogen activator in acute stroke.

METHODS

FSAP antigen, activity, and FSAP-inhibitor complexes were measured in 120 acute stroke patients admitted to Hospital Vall d'Hebron with arterial occlusions, before intravenous thrombolysis. Recanalization was assessed by transcranial Doppler 2 h after thrombolysis. Predictors of recanalization were determined by logistic regression analysis and the additional predictive value of FSAP over them was determined by integrated discrimination improvement index.

RESULTS

Complete recanalization was achieved in 31 patients. FSAP antigen levels were lower in patients achieving recanalization (8.2 (6.3-11.7) µg/mL vs. 9.8 (7.6-12.8) µg/mL; p = 0.046). After adjustment by age, sex, and National Institutes of Health Stroke Scale, Oxfordshire Community Stroke Project (odds ratio = 0.33 (0.13-0.82), p = 0.017) and FSAP antigen (odds ratio = 3.22 (1.22-8.47), p = 0.018) were independently associated with recanalization, and the addition of FSAP improved the model discrimination (integrated discrimination improvement = 5.5% (1.4-9.7), p = 0.009).

CONCLUSIONS

Our study showed that lower FSAP antigen plasma levels were associated with a higher chance of arterial recanalization after tissue plasminogen activator treatment, suggesting an involvement of FSAP in tissue plasminogen activator-induced clot lysis. FSAP antigen determination might be useful in predicting tissue plasminogen activator response in stroke patients.

Characterization of secretomes from a human blood brain barrier endothelial cells in-vitro model after ischemia by stable isotope labeling with aminoacids in cell culture (SILAC)

The human immortalized brain endothelial cell line hCMEC/D3 is considered a simple in-vitro model of the blood-brain-barrier. Our aim was to characterize changes in the secretome of hCMEC/D3 subjected to oxygen and glucose deprivation (OGD) to identify new proteins altered after ischemia and that might trigger blood-brain-barrier disruption and test their potential as blood biomarkers for ischemic stroke. Using a quantitative proteomic approach based on SILAC, 19 proteins were found differentially secreted between OGD and normoxia/normoglycemia conditions. Among the OGD-secreted proteins, protein folding was the main molecular function identified and for the main canonical pathways there was an enrichment in epithelial adherens junctions and aldosterone signaling. Western blot was used to verify the MS results in a set of 9 differentially secreted proteins and 5 of these were analyzed in serum samples of 38 ischemic stroke patients, 18 stroke-mimicking conditions and 18 healthy controls.

SIGNIFICANCE

"We characterized changes in the secretome of hCMEC/D3 cells after an ischemic insult by SILAC and identified proteins associated with ischemia that might be involved in the disruption of the blood-brain barrier. Besides we analyzed the putative potential of the candidate proteins to become biomarkers for the diagnosis of ischemic stroke.

Immunomodulation by interleukin-33 is protective in stroke through modulation of inflammation

Cerebral stroke induces massive Th1-shifted inflammation both in the brain and the periphery, contributing to the outcome of stroke. A Th1-type response is neurotoxic whereas a Th2-type response is accompanied by secretion of anti-inflammatory cytokines, such as interleukin-4 (IL-4). Interleukin-33 (IL-33) is a cytokine known to induce a shift towards the Th2-type immune response, polarize macrophages/microglia towards the M2-type, and induce production of anti-inflammatory cytokines. We found that the plasma levels of the inhibitory IL-33 receptor, sST2, are increased in human stroke and correlate with a worsened stroke outcome, suggesting an insufficient IL-33-driven Th2-type response. In mouse, peripheral administration of IL-33 reduced stroke-induced cell death and improved the sensitivity of the contralateral front paw at 5days post injury. The IL-33-treated mice had increased levels of IL-4 in the spleen and in the peri-ischemic area of the cortex. Neutralization of IL-4 by administration of an IL-4 antibody partially prevented the IL-33-mediated protection. IL-33 treatment also reduced astrocytic activation in the peri-ischemic area and increased the number of Arginase-1 immunopositive microglia/macrophages at the lesion site. In human T-cells, IL-33 treatment induced IL-4 secretion, and the conditioned media from IL-33-exposed T-cells reduced astrocytic activation. This study demonstrates that IL-33 is protective against ischemic insult by induction of IL-4 secretion and may represent a novel therapeutic approach for the treatment of stroke.

B-Type Natriuretic Peptides Help in Cardioembolic Stroke Diagnosis

Background and Purpose—

Determining the underlying cause of stroke is important to optimize secondary prevention treatment. Increased blood levels of natriuretic peptides (B-type natriuretic peptide/N-terminal pro-BNP [BNP/NT-proBNP]) have been repeatedly associated with cardioembolic stroke. Here, we evaluate their clinical value as pathogenic biomarkers for stroke through a literature systematic review and individual participants’ data meta-analysis.

Methods—

We searched publications in PubMed database until November 2013 that compared BNP and NT-proBNP circulating levels among stroke causes. Standardized individual participants’ data were collected to estimate predictive values of BNP/NT-proBNP for cardioembolic stroke. Dichotomized BNP/NT-proBNP levels were included in logistic regression models together with clinical variables to assess the sensitivity and specificity to identify cardioembolic strokes and the additional value of biomarkers using area under the curve and integrated discrimination improvement index.

Results—

From 23 selected articles, we collected information of 2834 patients with a defined cause. BNP/NT-proBNP levels were significantly elevated in cardioembolic stroke until 72 hours from symptoms onset. Predictive models showed a sensitivity >90% and specificity >80% when BNP/NT-proBNP were added considering the lowest and the highest quartile, respectively. Both peptides also increased significantly the area under the curve and integrated discrimination improvement index compared with clinical models. Sensitivity, specificity, and precision of the models were validated in 197 patients with initially undetermined stroke with final pathogenic diagnosis after ancillary follow-up.

Conclusions—

Natriuretic peptides are strongly increased in cardioembolic strokes. Future multicentre prospective studies comparing BNP and NT-proBNP might aid in finding the optimal biomarker, the best time point, and the optimal cutoff points for cardioembolic stroke identification.

NURR1 involvement in recombinant tissue-type plasminogen activator treatment complications after ischemic stroke

BACKGROUND AND PURPOSE

Despite the effectiveness of recombinant tissue-type plasminogen activator (r-tPA) during the acute phase of ischemic stroke, the therapy remains limited by a narrow time window and the occurrence of occasional vascular side effects, particularly symptomatic hemorrhages. Our aim was to investigate the mechanisms underlying the endothelial damage resulting from r-tPA treatment in ischemic-like conditions.

METHODS

Microarray analyses were performed on cerebral endothelial cells submitted to r-tPA treatment during oxygen and glucose deprivation to identify novel biomarker candidates. Validation was then performed in vivo in a mouse model of thromboembolic stroke and culminated in an analysis in a clinical cohort of patients with ischemic stroke treated with thrombolysis.

RESULTS

The transcription factor NURR1 (NR4A2) was identified as a downstream target induced by r-tPA during oxygen and glucose deprivation. Silencing NURR1 expression reversed the endothelial-toxicity induced by the combined stimuli, a protective effect attributable to reduced levels of proinflammatory mediators, such as nuclear factor-kappa-beta 2 (NF-κ-B2), interleukin 1 alpha (IL1α), intercellular adhesion molecule 1 (ICAM1), SMAD family member 3 (SMAD3), colony stimulating factor 2 (granulocyte-macrophage; CSF2). The detrimental effect of delayed thrombolysis, in conditions in which NURR1 gene expression was enhanced, was confirmed in the preclinical stroke model. Finally, we determined that patients with stroke who had a symptomatic hemorrhagic transformation after r-tPA treatment exhibited higher baseline serum NURR1 levels than did patients with an asymptomatic or absence of cerebral bleedings.

CONCLUSIONS

Our results suggest that NURR1 upregulation by r-tPA during ischemic stroke is associated with endothelial dysfunction and inflammation and the enhancement of hemorrhagic complications associated to thrombolysis.

Neuroendocrine hormones as prognostic biomarkers in the setting of acute stroke: overcoming the major hurdles

Stroke represents one of the major causes of disability and mortality worldwide and prediction of outcome represents a challenge for both clinicians and researchers. In the past years, many blood markers have been associated with stroke outcome but despite this evidence, no biomarker is routinely used in stroke management. In this review, we focus on markers of the neuroendocrine system, which represent potential candidates to be implemented in clinical practice. Moreover, we present a systematic review and literature-based meta-analysis for copeptin, a new biomarker of the hypothalamo-pituitary-adrenal axis that has shown additional predictive value over clinical information in a large prospective study. The meta-analysis of the included 7 studies, with more than 2000 patients, reinforced its association with poor outcome (pooled odds ratio: 2.474 [1.678-3.268]) and mortality (pooled OR: 2.569 [1.642-3.495]). We further review the current situation of the topic and next steps to implement these tools by clinicians.

Prognostic value of blood interleukin-6 in the prediction of functional outcome after stroke: a systematic review and meta-analysis

We aimed to quantify the association of blood interleukin-6 (IL-6) concentrations with poor outcome after stroke and its added predictive value over clinical information. Meta-analysis of 24 studies confirmed this association with a weighted mean difference of 3.443 (1.592-5.294) pg/mL, despite high heterogeneity and publication bias. Individual participant data including 4112 stroke patients showed standardized IL-6 levels in the 4th quartile were independently associated with poor outcome (OR=2.346 (1.814-3.033), p<0.0001). However, the additional predictive value of IL-6 was moderate (IDI=1.5%, NRI=5.35%). Overall these results indicate an unlikely translation of IL-6 into clinical practice for this purpose.

Fluorescent molecular peroxidation products: a prognostic biomarker of early neurologic deterioration after thrombolysis

BACKGROUND AND PURPOSE

Fluorescent molecular peroxidation products (FMPPs) are considered potential markers of molecular oxidative damage and may provoke increased permeability and disruption of the blood-brain barrier. This study aimed to determine the value of FMPPs as a biomarker to predict neurological worsening related to early hemorrhagic transformation.

METHODS

Baseline FMPP levels were measured in 186 consecutive acute ischemic stroke patients before tissue plasminogen activator treatment was administered. A serial FMPP profile (baseline before tissue plasminogen activator treatment, and 1, 2, 12, and 24 hours from treatment) was determined in a subset of 100 patients. Computed tomographic scans were performed at admission and repeated at 24 to 48 hours or after neurological worsening occurred. Symptomatic intracranial hemorrhage was defined as blood at any site in the brain associated with neurological deterioration.

RESULTS

Patients who worsened had higher median FMPP levels compared with those who did not (59.68 [48.63-85.73] versus 44.87 [36.37-58.90] Uf/mL; P=0.035) at baseline. After logistic regression multivariate analysis, FMPP >48.2 Uf/mL together with age, hypertension, and systolic blood pressure remained baseline predictors of worsening at 48 hours. Moreover, baseline FMPP determination helped to distinguish between patients who worsened and those who did not (Integrated Discrimination Improvement index, 5.7%; P=0.0004). Finally, within patients who had worsened at 48 hours, those with symptomatic intracranial hemorrhage had higher FMPP levels (P=0.038).

CONCLUSIONS

FMPPs might be a valuable biomarker of poor early neurological outcome and be related to the appearance of symptomatic intracranial hemorrhage in tissue plasminogen activator-treated patients, one of the most feared neurological complications after thrombolytic treatment of acute ischemic stroke.

B-type natriuretic peptides and mortality after stroke: a systematic review and meta-analysis

OBJECTIVE

To measure the association of B-type natriuretic peptide (BNP) and N-terminal fragment of BNP (NT-proBNP) with all-cause mortality after stroke, and to evaluate the additional predictive value of BNP/NT-proBNP over clinical information.

METHODS

Suitable studies for meta-analysis were found by searching MEDLINE and EMBASE databases until October 26, 2012. Weighted mean differences measured effect size; meta-regression and publication bias were assessed. Individual participant data were used to estimate effects by logistic regression and to evaluate BNP/NT-proBNP additional predictive value by area under the receiver operating characteristic curves, and integrated discrimination improvement and categorical net reclassification improvement indexes.

RESULTS

Literature-based meta-analysis included 3,498 stroke patients from 16 studies and revealed that BNP/NT-proBNP levels were 255.78 pg/mL (95% confidence interval [CI] 105.10-406.47, p = 0.001) higher in patients who died; publication bias entailed the loss of this association. Individual participant data analysis comprised 2,258 stroke patients. After normalization of the data, patients in the highest quartile had double the risk of death after adjustment for clinical variables (NIH Stroke Scale score, age, sex) (odds ratio 2.30, 95% CI 1.32-4.01 for BNP; and odds ratio 2.63, 95% CI 1.75-3.94 for NT-proBNP). Only NT-proBNP showed a slight added value to clinical prognostic variables, increasing discrimination by 0.028 points (integrated discrimination improvement index; p < 0.001) and reclassifying 8.1% of patients into correct risk mortality categories (net reclassification improvement index; p = 0.003). Neither etiology nor time from onset to death affected the association of BNP/NT-proBNP with mortality.

CONCLUSION

BNPs are associated with poststroke mortality independent of NIH Stroke Scale score, age, and sex. However, their translation to clinical practice seems difficult because BNP/NT-proBNP add only minor predictive value to clinical information.

Prognostic Value of Plasma Chitotriosidase Activity in Acute Stroke Patients

Background and aims

Chitotriosidase, a component of innate immunity, constitutes a sensitive parameter of macrophage activation and its elevated plasma activity reflects an inflammatory response. Given the deleterious effects of inflammation in brain ischemia, we aimed to assess the prognostic value of chitotriosidase activity in acute stroke patients.

Methods

The study comprised 159 acute stroke patients and 51 age-matched controls. Plasma chitotriosidase activity was serially determined by fluorometric assay. Short-term neurological outcome was determined at 48 h and functional outcome at three-months. Predictors of neurological and functional outcome were determined via multivariate analysis, and the additional predictive value of chitotriosidase was tested with the Integrated Discrimination Index and the Net Reclassification Improvement.

Results

Stroke patients showed increased levels of baseline chitotriosidase activity compared to controls [114·2 (74·65–182·95) nmol/ml/h vs. 54·4 (32·7–76·4); P < 0·0001]. Chitotriosidase activity (<118·75) was found to be an independent predictor of neurological improvement at 48 h (odds ratio: 3·25; 95% confidence interval: 1·54–6·85; P = 0·002), and the addition of plasma chitotriosidase activity showed a better prediction of improvement at 48 h (Integrated Discrimination Index = 5·7%, Net Reclassification Improvement = 11·6%, P < 0·05) over the predictive model constituted only with clinical information. Although patients disabled at three-months showed higher baseline chitotriosidase levels, it was not an independent predictor of long-term disability.

Conclusions

Baseline chitotriosidase activity in acute stroke patients treated with tissue plasminogen activator (tPA) may constitute a prognostic predictor of short-term outcome, adding a moderate additional predictive value. Our results underline the deleterious role of inflammation in acute stroke patients.

Cerebral ischaemia and matrix metalloproteinase-9 modulate the angiogenic function of early and late outgrowth endothelial progenitor cells

The enhancement of endogenous angiogenesis after stroke will be critical in neurorepair therapies where endothelial progenitor cells (EPCs) might be key players. Our aim was to determine the influence of cerebral ischaemia and the role of matrix metalloproteinase-9 (MMP-9) on the angiogenic function of EPCs. Permanent focal cerebral ischaemia was induced by middle cerebral artery (MCA) occlusion in MMP-9/knockout (MMP-9/KO) and wild-type (WT) mice. EPCs were obtained for cell counting after ischaemia (6 and 24 hrs) and in control animals. Matrigel(™) assays and time-lapse imaging were conducted to monitor angiogenic function of WT and MMP9-deficient EPCs or after treatment with MMP-9 inhibitors. Focal cerebral ischaemia increased the number of early EPCs, while MMP-9 deficiency decreased their number in non-ischaemic mice and delayed their release after ischaemia. Late outgrowth endothelial cells (OECs) from ischaemic mice shaped more vessel structures than controls, while MMP-9 deficiency reduced the angiogenic abilities of OECs to form vascular networks, in vitro. Treatment with the MMP inhibitor GM6001 and the specific MMP-9 inhibitor I also decreased the number of vessel structures shaped by both human and mouse WT OECs, while exogenous MMP-9 could not revert the impaired angiogenic function in MMP-9/KO OECs. Finally, time-lapse imaging showed that the extension of vascular networks was influenced by cerebral ischaemia and MMP-9 deficiency early during the vascular network formation followed by a dynamic vessel remodelling. We conclude that focal cerebral ischaemia triggers the angiogenic responses of EPCs, while MMP-9 plays a key role in the formation of vascular networks by EPCs.

Immunological biomarkers improve the accuracy of clinical risk models of infection in the acute phase of ischemic stroke

Infection is an independent risk factor for adverse outcome in stroke patients. The risk of developing an infection in this setting is partly related to a stroke-induced immunodepression, in which a shift to a predominant Th2 (immunosuppressive) phenotype has been postulated to play a major role. Our aim was to study whether clinical variables or changes in plasma cytokine expression can predict poststroke infections.

PATIENTS AND METHODS

Medical records of 92 stroke patients were reviewed, and the baseline concentration of cytokines from the Th1/Th2 system was determined. Clinical and serological predictors of incident infections and their prognostic significance were sought by means of univariate and multivariate analysis, and two predictive models for developing an infection were constructed by combining independent predictors (strictly clinical in one, and both clinical and serological in the other) for this outcome. The improvement conferred by the addition of immunological markers to the clinical model was assessed by comparing their respective ROC curves and by improvement (Net Reclassification Index and Integrated Discriminator Improvement) analysis.

RESULTS

Nineteen patients (20.7% of the study sample) developed an infection. Ongoing antiplatelet therapy at symptom onset (OR 0.02, 95% CI 0.001-0.23, p = 0.001), diabetes mellitus (OR 9.96, 95% CI 1.32-75.29, p = 0.03), IL-13 level <33 pg/ml (OR 84.16, 95% CI 2.53-2795.18, p = 0.01) and interferon-γ level >8.4 pg/ml (OR 60.17, 95% CI 1.78-2037.23, p = 0.02) were independently associated with the development of infections during hospital admission. The combined regression model predicted infection with an accuracy of 93.4%, an improvement in the predictive capacity of 17% (p < 0.001). Infection was associated with a worse neurological status at hospital discharge (median NIHSS score 11 (6-18) vs. 4 (1-11.5), p = 0.014).

CONCLUSIONS

This study shows that bloodstream biomarkers are useful to improve the accuracy of clinical prognostic models for infection in the acute phase of stroke. The clinical predictors of infection in the acute phase of stroke are relatively well established in the medical literature, but further research to identify the optimal combination of biomarkers (possibly inflammatory and stress markers) to be included in a clinically useful model is needed. Such a model could be subsequently used in clinical trials to assess the effect of prophylactic and/or early antibiotic therapy in this setting, a currently controversial issue in this field.

A new method for focal transient cerebral ischaemia by distal compression of the middle cerebral artery

AIMS

Rodent experimental models are essential for in vivo study of stroke. Our aim was to develop a reproducible method of mouse transient focal cerebral ischaemia by distal artery compression.

METHODS

The distal middle cerebral artery (dMCA) was occluded by compression with a blunted needle, and cerebral blood flow was monitored by laser Doppler flowmetry to ensure appropriate occlusion and reperfusion in Balb/c mice. The ischaemic lesion was evaluated 24 h after occlusion by TTC staining and immunolabelling (NeuN, CD31, GFAP and Iba-1) while the established permanent dMCA occlusion (dMCAO) model was used as a control. The corner test was performed to evaluate neurological behaviour.

RESULTS

Laser Doppler flowmetry register showed a homogenous arterial occlusion among animals. Forty-five minutes of arterial occlusion did not lead brain infarction when evaluated by TTC staining 24 h after occlusion. Extending the cerebral ischaemia period to 60 min induced a cortically localized homogeneous brain infarct. No differences in infarct volume were detected between animals submitted to permanent or 60-min transient dMCAO (42.33 ± 9.88 mm³ and 37.63 ± 12.09 mm³ respectively). The ischaemic injury was confirmed by immunohistochemistry in the 60-min transient dMCAO model but not in the 45-min model. Neurological deficits assessed with the corner test were significant only during the first 48 h but not at long term.

CONCLUSIONS

This work shows an easy-to-perform method for the induction of brain ischaemia and reperfusion to assess stroke repair and treatment screening, with cortically localized ischaemic cell damage, low mortality and neurological impairment in the acute phase.

Decreased levels of angiogenic growth factors in intracranial atherosclerotic disease despite severity-related increase in endothelial progenitor cell counts

BACKGROUND

Intracranial atherosclerotic disease (ICAD) is an important cause of ischemic stroke (IS) and endothelial dysfunction plays a critical role in its onset and progression. Endothelial progenitor cells (EPCs) and endothelial production of angiogenic growth factors (AGFs) may play an essential role in this process. This study investigated the association of EPCs and AGFs with ICAD severity.

METHODS

A total of 42 patients who had experienced a transient ischemic attack (TIA) or IS attributable to symptomatic ICAD were included. Clinical and neurosonological evaluations were conducted between 2.4 and 8.7 years after the initial cerebrovascular event. Severe ICAD was defined as the presence of at least 1 severe intracranial stenosis, and extensive ICAD as 3 or more intracranial stenoses. Blood samples were obtained to determine EPC levels using flow cytometry (CD34+KDR+ cells), and the plasma levels of several growth factors were assessed with a protein array (Searchlight(®)). Twenty-two individuals without cerebrovascular disease and with normal ultrasonographic examination were also included.

RESULTS

No difference in the count of circulating EPCs was found between patients and controls, and a moderate increase in the number of EPCs/ml was noted in patients with extensive ICAD (p = 0.05). Patients presented decreased levels of fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF-BB) compared with controls (p = 0.002, p = 0.079 and p = 0.061, respectively). Higher levels of FGF, VEGF and PDGF-BB were found in patients with severe ICAD (p = 0.007, p = 0.07 and p = 0.07, respectively), but there was no correlation between any AGFs and EPCs.

CONCLUSIONS

Symptomatic ICAD patients have decreased levels of AGFs with no correlation to the number of circulating EPCs, while patients with severe ICAD have higher levels of EPCs, FGF, VEGF and PDGF-BBs. This suggests that reduced EPC and proangiogenic factor production capacity is implicated in ICAD pathogenesis, while the more severe forms of chronic brain hypoperfusion in ICAD patients might stimulate EPC mobilization and AGF production.

Citicoline in pre-clinical animal models of stroke: a meta-analysis shows the optimal neuroprotective profile and the missing steps for jumping into a stroke clinical trial

The neuroprotective actions of citicoline have been documented for experimental stroke therapy. We used a systematic review and meta-analysis to assess this evidence. From 64 identified studies using citicoline in stroke animal models, only those describing ischemic occlusive stroke and reporting data on infarct volume and/or neurological outcome were included (14 studies, 522 animals). Overall, the quality of the studies was modest (5, 4-6), while the absence of studies involving animals with co-morbidities, females, old animals or strain differences indicated that studies did not fulfill the STAIR recommendations. Weighted mean difference meta-analysis showed citicoline to reduce infarct volume by 27.8% [(19.9%, 35.6%); p < 0.001]. In the stratified analysis, citicoline effect on reducing infarct volume was higher in proximal occlusive models of middle cerebral artery (MCA) compared with distal occlusion. Moreover, the efficacy was superior using multiple doses than single dose and when a co-treatment was administered compared with citicoline monotherapy, the only independent factor identified in the meta-regression. Citicoline improved neurological deficit by 20.2% [(6.8%, 33.7%); p = 0.015], but only four studies including 176 animals reported these data. In conclusion, this meta-analysis provides evidence of citicoline efficacy in stroke animal models and shows the optimal neuroprotective profile and the missing experimental requirements before jumping into clinical trials.

Evidence for the efficacy of statins in animal stroke models: a meta-analysis

Protective effects of statins have been well documented for stroke therapy. Here, we used a systematic review and meta-analysis to assess these evidences. We identified 190 studies using statin treatment in stroke animal models by electronic searching. From those, only studies describing ischemic occlusive stroke and reporting data on infarct volume and/or neurological outcome were included in the analysis (41 publications, 1882 animals). The global estimate effect was assessed by Weighted Mean Difference meta-analysis. Statins reduced infarct volume by 25.12% (20.66%-29.58%, P < 0.001) and consistently, induced an improvement on neurological outcome (20.36% (14.17%-26.56%), P < 0.001). Stratified analysis showed that simvastatin had the greatest effect on infarct volume reduction (38.18%) and neurological improvement (22.94%), whereas bigger infarct reduction was observed giving the statin as a pre-treatment (33.5%) compared with post-treatment (16.02%). The use of pentobarbital sodium, the timing of statin administration, the statement of conflict of interest and the type of statin studied were found to be independent factors in the meta-regression, indicating their influence on the results of studies examining statin treatment. In conclusion, this meta-analysis provides further evidences of the efficacy of statins, supporting their potential use for human stroke therapy.

Role of the MMP9 gene in hemorrhagic transformations after tissue-type plasminogen activator treatment in stroke patients

BACKGROUND AND PURPOSE

Despite the benefits of tissue-type plasminogen activator treatment, some stroke patients experience adverse hemorrhagic transformations (HT). Plasma protein levels of MMP9 have been associated with HT occurrence. We aimed to analyze the association of the MMP9 gene with HT occurrence.

METHODS

We analyzed the MMP9 gene in blood samples from 885 stroke patients treated with tissue-type plasminogen activator by tag-SNP, imputed SNP, direct sequencing, and RNA expression.

RESULTS

We did not observe any significant association between MMP9 genetic variations or MMP9 expression and HT occurrence. Moreover, no association was found between MMP9 expression and MMP9 polymorphisms.

CONCLUSIONS

Genetic variations in the MMP9 gene are not associated with HT occurrence in tissue-type plasminogen activator-treated patients.

Differentiating ischemic from hemorrhagic stroke using plasma biomarkers: the S100B/RAGE pathway

Although neuroimaging is useful in differentiating ischemic (IS) from hemorrhagic (ICH) stroke in the Emergency Department, a wide-available rapid biochemical test would add advantages in the pre-hospital triage and management of stroke patients. Our aim was to examine the predictive value of a panel of blood-borne biomarkers to differentiate IS from ICH. Admission blood samples obtained within 24h from stroke symptoms onset were tested by ELISA for CRP, D-dimer, sRAGE, MMP9, S100B, BNP, NT-3, caspase-3, chimerin-II, secretagogin, cerebellin and NPY. The complete protocol was achieved in 915 patients (776 IS, 139 ICH). Among blood samples obtained <6 h from symptoms onset (n=337), S100B levels were increased in ICH (107.58 vs 58.70 pg/mL; p<0.001) whereas sRAGE levels were decreased (0.77 vs 1.02 ng/mL; p=0.009) as compared to IS. In this subset of patients S100B (OR 3.97 95% CI 1.82-8.68; p=0.001) and sRAGE (OR 0.22 95% CI 0.10-0.52; p<0.001) were independently associated with ICH. A regression tree was created by CART method showing good classification ability (AUC=0.762). Similar results were found for samples obtained within 3 h. In conclusion, a combination of biomarkers including those of the S100B/RAGE pathway seems promising to achieve a rapid biochemical diagnosis of IS versus ICH in the first hours from symptoms onset. This article is part of a Special Issue entitled: Translational Proteomics.

The gender gap in stroke: a meta-analysis

Several studies have indicated that gender differences might exist in stroke.

OBJECTIVES AND METHODS

Our goal was to perform a comprehensive meta-analysis in order to evaluate and quantify stroke gender disparities through a systematic search of relevant articles published up to October 2009 and addressing gender related differences in ischemic stroke risk factors, stroke subtype and severity, diagnostic tests, and acute phase and secondary prevention treatments.

RESULTS

Forty-five articles were included in the analysis, representing a total of 673,935 patients. Women were globally older than men (+5.2 years) and suffered more hypertension (P = 0.017) and atrial fibrillation (P < 0.001), although they were less likely to drink alcohol (P < 0.001), smoke cigarettes (P < 0.001), present hyperlipidemia (P = 0.033) or diabetes (P = 0.003) than men. Baseline stroke severity was not different between genders. Women suffered more cardioembolic strokes, while men had more atherothrombotic strokes. Moreover, women were less likely to receive stroke-related treatments, such as antiplatelets (P < 0.001), statins (P < 0.001), and tPA (P < 0.001) than men. Although meta-regression did not identify age or stroke etiology as sources of heterogeneity, caution should be taken as that analysis was possible only for gender differences in secondary prevention with antiplatelets because of limited data for other end points.

CONCLUSIONS

Gender differences have been identified on the risk factors profile and diagnostic and therapeutic management of patients with ischemic stroke. Active measures should thus be taken to avoid bias in clinical practice.

VAP-1/SSAO plasma activity and brain expression in human hemorrhagic stroke

BACKGROUND

Vascular adhesion protein-1 (VAP-1) is a cell surface and circulating enzyme that belongs to the semicarbazide-sensitive amine oxidase (SSAO) family, which oxidatively deaminates primary amines and is implicated in leukocyte extravasation. Our aim was to investigate the alteration of soluble VAP-1/SSAO activity in plasma samples after acute intracerebral hemorrhage (ICH) and its presence in human ICH brain tissue.

METHODS

VAP-1/SSAO activity was determined in plasma of 66 ICH patients and 58 healthy controls. In addition, we assessed the expression of VAP-1/SSAO in postmortem brain tissue from hemorrhagic stroke patients by Western blot and immunohistochemistry.

RESULTS

We observed significantly higher levels of plasma VAP-1/SSAO activity in patients with ICH compared to matched elderly controls (p = 0.001). Plasma VAP-1/SSAO activity <2.7 pmol/min·mg and baseline ICH volume <17 ml were independent predictors of neurological improvement after 48 h (OR 6.8, 95% CI 1.14-41.67, p = 0.035, and OR 10.64, 95% CI 1.1-100, p = 0.041, respectively), after adjustment for baseline stroke severity. We also found that membrane-bound VAP-1/SSAO levels were lower in the perihematoma region than in the corresponding contralateral brain areas of patients deceased due to ICH (p = 0.024).

CONCLUSIONS

Our data demonstrate that plasma VAP-1/SSAO activity is increased in ICH and predicts neurological outcome, suggesting a possible contribution of the soluble protein in secondary brain damage. Furthermore, anti-VAP-1/SSAO strategies might be a promising approach to prevent neurological worsening following ICH.

Lipoprotein-associated phospholipase A2 testing usefulness among patients with symptomatic intracranial atherosclerotic disease

BACKGROUND AND PURPOSE

Circulating lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) has emerged as a novel biomarker for cardiovascular diseases. Our aim was to determine Lp-PLA(2) mass and activity in a selected cohort of first-ever transient ischemic attack (TIA) or ischemic stroke patients with intracranial atherosclerotic disease (ICAD) and to investigate its relationship with the presence of classical vascular risk factors, response to secondary prevention treatments and risk of recurrent vascular events.

METHODS

Lp-PLA(2) mass and activity were measured 3 months after TIA or stroke by means of the PLAC test and CAM-assay (diaDexus, Inc.) respectively in 75 patients. Classic vascular risk factors, preventive treatments and clinical characteristics at the time of the index event were recorded. Follow-up transcranial Doppler ultrasonography (TCD) was performed and the presence of a new vascular event was assessed every 6 months.

RESULTS

Several preventive treatments (statins and clopidogrel) were significantly associated with lower Lp-PLA(2) mass and activity. During follow-up (median time 23 months), eighteen patients (24%) suffered a new vascular event. Baseline factors associated with new vascular events were: history of coronary artery disease, number of intracranial stenoses detected by TCD and also Lp-PLA(2) activity, which was the only independent predictor for new vascular events (hazard ratio 2.89; 95% CI 1.029 to 8.096; p=0.044) after multivariate analysis (Cox regression).

CONCLUSIONS

Lp-PLA(2) activity might be a useful tool to identify intracranial large-artery occlusive disease patients at higher risk of suffering new vascular events.

Update on the Serum Biomarkers and Genetic Factors Associated with Safety and Efficacy of rt-PA Treatment in Acute Stroke Patients

An accurate understanding of the mechanisms underlying an individual's response to rt-PA treatment is critical to improve stroke patients' management. We thus reviewed the literature in order to identify biochemical and genetic factors that have been associated with safety and efficacy of rt-PA administration after stroke.

Leukoaraiosis is associated with genes regulating blood-brain barrier homeostasis in ischaemic stroke patients

BACKGROUND

The biologic agents causing leukoaraiosis are unknown. Our aim was to study the genetic basis of leukoaraiosis.

METHODS

We analyzed 212 single nucleotide polymorphisms (SNPs) in 142 patients with ischaemic stroke, generating a total of 30,104 genotypes. Seventy-nine subjects (55.6%) presented leukoaraiosis measured by the Fazekas scale and 69 (48.6%) by ARWMC scale. We analyzed the presence of synergic associations between SNPs using the hfcc software. Finally, functional studies were performed in 56 subjects. The Ingenuity Pathways software (ipa) was used to examine the role of the identified genes.

RESULTS

Six SNPs were associated with leukoaraiosis using both measuring scales. After logistic regression adjusted for leukoaraiosis risk factors, the rs2252070 of MMP13 (OR = 4.9, 95%CI: 1.34-17.9, P = 0.016), rs662 of PON1 (OR = 0.37, 95%CI: 0.15-0.87, P = 0.024) and rs1800779 of NOS3 (OR = 3.9, 95%CI: 1.38-11.38, P = 0.01) were independently associated with leukoaraiosis under a dominant/recessive model and the rs2290608 of IL5RA (OR = 0.46, 95%CI: 0.25-0.85, P = 0.013) and rs669 of A2M (OR = 2.5, 95%CI: 1.36-4.83, P = 0.004) under an additive model. Computational analysis showed a synergic association of rs10497212-AA of ITGB6 and rs2290608-GG of IL5RA with leukoaraiosis using both scales. (i) ARWMC (P = 1.3 × 10(-4) ) and (ii) Fazekas (P = 4.5 × 10(-5) ). Functional studies showed that the rs669 SNP was associated with plasma levels of A2M (P = 0.012) and A2M levels with leukoaraiosis in Fazekas scale (P = 0.02). ipa analysis revealed that the genes associated with leukoaraiosis were involved in blood-brain barrier (BBB) homeostasis.

CONCLUSIONS

Amongst patients with ischaemic stroke, several genes associated with BBB homeostasis could be involved with a higher risk of leukoaraiosis.

CD40-1C>T polymorphism (rs1883832) is associated with brain vessel reocclusion after fibrinolysis in ischemic stroke

AIMS

To find genetic predictors of reocclusion after successful fibrinolytic therapy during the acute phase of ischemic stroke.

PATIENTS & METHODS

This was a case-case prospective study analyzing 236 polymorphisms in a cohort of 222 patients treated with tissue plasminogen activator, from which 16 patients suffered a reocclusion event (7.2%). A predictive scale was generated using independent polymorphisms with a dominant/recessive model and tandem occlusion, weighted by their beta-coefficients in logistic regression.

RESULTS

Using a dominant/recessive model, the rs1800801 SNP from the MGP gene (odds ratio [OR]: 15.25; 95% CI: 2.23-104.46; adjusted p = 0.006) and the rs1883832 SNP from CD40 gene (OR: 0.077; 95% CI: 0.009-0.66; adjusted p = 0.019) were independently associated with reocclusion after logistic regression adjustment by clinical predictors. In an additive model, only the rs1883832 SNP (OR: 4.43; 95% CI: 1.62-12.15; adjusted p = 0.004) was related to reocclusion occurrence. The predictive model that was generated stratified the reocclusion risk from less than 1% to more than 70%. Reocclusions were associated with neurological worsening at 24 h (patients with reocclusion: 26.7%, versus patients without reocclusion: 4.9%; p = 0.002), as it was seen for MGP -7A>G (AA: 17.2% vs AG+GG: 4.5%; p = 0.027), but not for CD40 1C>T (CC: 4.5% vs CT+TT: 7.7%; p = 0.565). There was an association between CD40 -1C>T genotype and CD40 transcriptional activity in peripheral blood mononuclear cells (median expression values TT: 65.75%, CT: 70.80%, CC: 96.00%; p = 0.023). However, CD40 soluble fraction was not a useful biomarker of reocclusion status.

CONCLUSION

An association was found between MGP -7A>G and CD40 -1C>T polymorphisms, and reocclusion risk. The predictive scale that was generated permits the stratification of patients by their reocclusion risk with higher accuracy than clinical parameters alone.