Blood biomarkers for the diagnosis of acute cerebrovascular diseases: a prospective cohort study

Advances in development of biomarkers for brain damage and ischemia

Acquired brain injury is an urgent situation that requires rapid diagnosis and treatment. Magnetic resonance imaging (MRI) and computed tomography (CT) are required for accurate diagnosis. However, these methods are costly and require substantial infrastructure and specialized staff. Circulatory biomarkers of acute brain injury may help in the management of patients with acute cerebrovascular events and prevent poor outcome and mortality. The purpose of this review is to provide an overview of the development of potential biomarkers of brain damage to increase diagnostic possibilities. For this purpose, we searched the PubMed database of studies on the diagnostic potential of brain injury biomarkers. We also accessed information from Clinicaltrials.gov to identify any clinical trials of biomarker measurements for the diagnosis of brain damage. In total, we present 41 proteins, enzymes and hormones that have been considered as biomarkers for brain injury, of which 20 have been studied in clinical trials. Several microRNAs have also emerged as potential clinical biomarkers for early diagnosis. Combining multiple biomarkers in a panel, along with other parameters, is yielding promising outcomes.

Releasing Dynamic of Serum ST2 and Calprotectin in Patients with Acute Ischemic Stroke

This study investigated the releasing dynamics of serum ST2 and calprotectin in patients with acute IS. The study included acute IS patients (N = 20) with an NIH Stroke Scale score ≥8. Sampling was performed at seven time points: after admission (T0) and at the following 24 h consecutive intervals (T1-T6). Primary outcome at 90 days was evaluated using the modified Rankin scale: 0-2 for good and 3-6 for poor functional outcome. The secondary outcome was all-cause mortality after 90 days. Fifteen patients had a poor outcome, and eight died. Results showed a statistically significant difference in ST2 concentrations between good and poor outcomes at T0 (p = 0.04), T1 (p = 0.006), T2 (p = 0.01), T3 (p = 0.021), T4 (p = 0.007), T5 (p = 0.032), and for calprotectin T6 (p = 0.034). Prognostic accuracy was highest for ST2 at T1 for a cut-off > 18.9 µg/L (sensitivity 80% and specificity 100.0%) and for calprotectin at T5 for a cut-off > 4.5 mg/L (sensitivity 64.3% and specificity 100.0%). Serum ST2 and calprotectin-releasing dynamics showed a valuable prognostic accuracy for IS outcomes.

Clinical Significance of MicroRNA-330-3p in Plasma Level for Acute Cerebral Infarction

INTRODUCTION

The present study was to investigate the clinical role of miR-330-3p in acute cerebral infarction (ACI), including its diagnostic and prognostic potential. Preliminary exploration of its target genes was archived by bioinformatics analysis.

METHODS

miR-330-3p in plasma of the patients with ACI and controls were quantified by real-time quantitative PCR. The 1-month prognosis of the ACI patients was evaluated by the Glasgow Outcome Scale (GOS). The correlation between the plasma levels of miR-330-3p and the GOS scores was tested by Pearson correlation analysis. The receiver operating characteristic (ROC) curves were established based on the expression level of miR-330-3p in different groups. The miR-330-3p-targeting genes were analyzed using Venn diagram, protein-protein interaction network, and Gene Ontology enrichment analysis.

RESULTS

miR-330-3p was significantly increased in the plasma of ACI patients compared with that in healthy controls, and ROC curve revealed its diagnostic value for ACI. miR-330-3p was significantly increased in the plasma of patients with poor 1-month prognosis compared with those with good 1-month prognosis. miR-330-3p expression was negatively correlated with GOS score, suggesting its potential to predict the 1-month prognosis for ACI. One-year survival analysis revealed surviving patients had lower levels of miR-330-3p than the deceased. miR-330-3p was proven to predict the death of patients with ACI. The miR-330-3p-targeting genes were associated with synapse-related Gene Ontology terms.

CONCLUSION

miR-330-3p was upregulated in the plasma of patients with ACI, making it a promising diagnostic and prognostic marker for patients with ACI. miR-330-3p could facilitate synaptic plasticity following cerebral infarction.

Diagnostic and Prognostic Blood Biomarkers in Transient Ischemic Attack and Minor Ischemic Stroke: An Up-To-Date Narrative Review

INTRODUCTION

Early diagnosis and correct risk stratification in patients with transient ischemic attack (TIA) and minor ischemic stroke (MIS) is crucial for the high rate of subsequent disabling stroke. Although highly improved, diagnosis and prognostication of TIA/MIS patients remain still based on clinical and neuroimaging findings, with some inter-rater variability even among trained neurologists.

OBJECTIVES

To provide an up-to-date overview of diagnostic and prognostic blood biomarkers in TIA and MIS patients.

MATERIAL AND METHODS

We performed a bibliographic search on PubMed database with last access on July 10^th 2021. More than 680 articles were screened and we finally included only primary studies on blood biomarkers.

RESULTS

In a narrative fashion, we discussed about blood biomarkers investigated in TIA/MIS patients, including inflammatory, thrombosis, neuronal injury and cardiac analytes, antibodies and microRNAs. Other soluble molecules have been demonstrated to predict the risk of recurrent cerebrovascular events or treatment response in these patients. A rapid point of care assay, combining the determination of different biomarkers, has been developed to improve triage recognition of acute cerebrovascular accidents.

CONCLUSIONS

The implementation of blood biomarkers in the clinical management of TIA/MIS could ameliorate urgent identification, risk stratification and individual treatment choice. Large prospective and longitudinal studies, adopting standardized sampling and analytic procedures, are needed to clarify blood biomarkers kinetic and their relationship with TIA and minor stroke etiology.

Clinical and molecular correlates of the ASPECTS in the acute phase of stroke

BACKGROUND

The Alberta Stroke Program Early CT Score (ASPECTS) scale was developed for monitoring early ischemic changes on CT, being associated with clinical outcomes. The ASPECTS can also associate with peripheral biomarkers that reflect the pathophysiological response of the brain to the ischemic stroke.

OBJECTIVE

To investigate the association between peripheral biomarkers with the Alberta Stroke Program Early CT Score (ASPECTS) in individuals after ischemic stroke.

METHODS

Patients over 18 years old with acute ischemic stroke were enrolled in this study. No patient was eligible for thrombolysis. The patients were submitted to non-contrast CT in the first 24 hours of admission, being the Alberta Stroke Program Early CT Score and clinical and molecular evaluations applied on the same day. The National Institutes of Health Stroke Scale (NIHSS), modified Rankin scale and the Mini-Mental State Examination for clinical evaluation were also applied to all subjects. Plasma levels of BDNF, VCAM-1, VEGF, IL-1β, sTNFRs and adiponectin were determined by ELISA.

RESULTS

Worse neurological impairment (NIHSS), cognitive (MEEM) and functional (Rankin) performance was observed in the group with changes in the NCTT. Patients with NCTT changes also exhibited higher levels of IL-1β and adiponectin. In the linear multivariate regression, an adjusted R coefficient of 0.515 was found, indicating adiponectin and NIHSS as independent predictors of ASPECTS.

CONCLUSION

Plasma levels of adiponectin are associated with the ASPECTS scores.

Occult primary brain cancers manifesting in the aftermath of ischaemic and haemorrhagic stroke

Introduction

Symptoms of occult brain cancer may mimic stroke. Misdiagnosis may lead to improper treatment and delayed diagnosis. We characterised strokes associated with occult primary brain cancer and determined risk that ischaemic and haemorrhagic strokes are associated with occult primary brain cancer.

Patients and methods

All patients with incident stroke in Denmark 2003-2015 were identified through the Danish Stroke Registry (n = 85,893) and matched 1:10 on age and sex to the Danish background population without a stroke history (n = 858,740). This cohort was linked to the Danish Cancer Registry and prevalence of occult primary brain cancer defined as the event of previously unknown primary brain cancer during a one-year follow-up was estimated. We used Cox regression models to study risk of occult primary brain cancer in comparison to the background population.

Results

Of 77,484 patients with ischaemic strokes, 39 (1 in 2000) were associated with primary brain cancer; of 8409 with haemorrhagic strokes, it was 126 (1 in 66). In the background cohort, 205 (1 in 4000) had occult primary brain cancer. The multivariate stroke risk factor analysis showed that patients with occult primary brain cancer differed significantly from those without occult primary brain cancer indicating they might have stroke mimics rather than true strokes.Discussion and conclusions: Strokes associated with occult primary brain cancer tend to be stroke mimics rather than true strokes. Primary brain cancer is rare in patients with ischaemic stroke (1 in 2000); risk that misdiagnosis results in maltreatment is, therefore, very low. Occult primary brain cancers are mainly found among patients with haemorrhagic stroke; they are not uncommon (1 in 66) and should always be kept in mind.

Proteomics Analysis of Brain Tissue in a Rat Model of Ischemic Stroke in the Acute Phase

Background: Stroke is a leading health issue, with high morbidity and mortality rates worldwide. Of all strokes, approximately 80% of cases are ischemic stroke (IS). However, the underlying mechanisms of the occurrence of acute IS remain poorly understood because of heterogeneous and multiple factors. More potential biomarkers are urgently needed to reveal the deeper pathogenesis of IS.

Methods: We identified potential biomarkers in rat brain tissues of IS using an iTRAQ labeling approach coupled with LC-MS/MS. Furthermore, bioinformatrics analyses including GO, KEGG, DAVID, and Cytoscape were used to present proteomic profiles and to explore the disease mechanisms. Additionally, Western blotting for target proteins was conducted for further verification.

Results: We identified 4,578 proteins using the iTRAQ-based proteomics method. Of these proteins, 282 differentiated proteins, comprising 73 upregulated and 209 downregulated proteins, were observed. Further bioinformatics analysis suggested that the candidate proteins were mainly involved in energy liberation, intracellular protein transport, and synaptic plasticity regulation during the acute period. KEGG pathway enrichment analysis indicated a series of representative pathological pathways, including energy metabolite, long-term potentiation (LTP), and neurodegenerative disease-related pathways. Moreover, Western blotting confirmed the associated candidate proteins, which refer to oxidative responses and synaptic plasticity.

Conclusions: Our findings highlight the identification of candidate protein biomarkers and provide insight into the biological processes involved in acute IS.

Candidate Biomarkers for the Diagnosis of Transient Ischemic Attack: A Systematic Review

BACKGROUND AND PURPOSE

A rapid serum biomarker that confirms or rules out a transient ischemic attack (TIA) would be of great value in clinical practice. We aimed to systematically review current evidence for the diagnostic accuracy of blood biomarkers in the early diagnosis of TIA.

METHODS

This is a systematic review with quality appraisal of individual studies using the QUADAS-2 tool. MEDLINE and EMBASE databases were searched up to May 1, 2017, to select primary diagnostic accuracy studies evaluating potential biomarkers in blood for the diagnosis of TIA or ischemic stroke.

RESULTS

Of 4,215 studies retrieved, 78 met our eligibility criteria. Forty-five studies restricted their population to ischemic stroke patients, 32 included both TIA and ischemic stroke patients, and only one study was restricted to TIA patients. In total 62/78 (79.5%) studies had a case-control design comparing TIA or stroke patients with healthy subjects. Overall, 125 single biomarkers and 5 biomarker panels were studied, with a median number of participants per study of 92.0 (interquartile range 44.8-144.5), varying from 8 to 915. Sufficient information to extract 2 × 2 tables was available for 35 (44.9%) articles, and for 60 (48.0 %) biomarkers. Several markers, such as NR2A/B (antibodies), Parkinson 7, nucleoside diphosphate kinase A, ubiquitin fusion degradation protein-1, and heart-type fatty acid binding protein, have shown moderate to high diagnostic accuracy in multiple studies.

CONCLUSIONS

Although the methodological quality of studies evaluating biomarkers of brain ischemia was poor, several biomarkers have shown the potential to detect transient brain ischemia in an early phase. Diagnostic accuracy studies in suspected cases of TIA are needed to determine their true clinical value.

Point-of-care measurements reveal release of purines into venous blood of stroke patients

Stroke is a leading cause of death and disability. Here, we examine whether point-of-care measurement of the purines, adenosine, inosine and hypoxanthine, which are downstream metabolites of ATP, has potential to assist the diagnosis of stroke. In a prospective observational study, patients who were suspected of having had a stroke, within 4.5 h of symptom onset and still displaying focal neurological symptoms at admission, were recruited. Clinical research staff in the Emergency Departments of two hospitals used a prototype biosensor array, SMARTCap, to measure the purines in the venous blood of stroke patients and healthy controls. In controls, the baseline purines were 7.1 ± (SD) 4.2 μM (n = 52), while in stroke patients, they were 11.6 ± 8.9 μM (n = 76). Using the National Institutes for Stoke Scale (NIHSS) to band the severity of stroke, we found that minor, moderate and severe strokes all gave significant elevation of blood purines above the controls. The purine levels fall over 24 h. This was most marked for patients with haemorrhagic strokes (5.1 ± 3.6 μM, n = 9 after 24 h). The purine levels measured on admission show a significant correlation with the volume of affected brain tissue determined by medical imaging in patients who had not received thrombolysis or mechanical thrombectomy.

ClinicalTrials.gov Identifier: NCT02308605

Retrospective evaluation of a clinical decision support tool for effective computed tomography angiography utilization in urgent brain imaging of suspected TIA/minor stroke in the emergency department

OBJECTIVES

The Canadian Stroke Best Practice Recommendations suggests that patients suspected of transient ischemic attack (TIA)/minor stroke receive urgent brain imaging, preferably computed tomography angiography (CTA). Yet, high requisition rates for non-cerebrovascular patients overburden limited radiological resources, putting patients at risk. We hypothesize that our clinical decision support tool (CDST) developed for risk stratification of TIA in the emergency department (ED), and which incorporates Canadian guidelines, could improve CTA utilization.

METHODS

Retrospective study design with clinical information gathered from ED patient referrals to an outpatient TIA unit in Victoria, BC, from 2015-2016. Actual CTA orders by ED and TIA unit staff were compared to hypothetical CTA ordering if our CDST had been used in the ED upon patient arrival.

RESULTS

For 1,679 referrals, clinicians ordered 954 CTAs. Our CDST would have ordered a total of 977 CTAs for these patients. Overall, this would have increased the number of imaged-TIA patients by 89 (10.1%) while imaging 98 (16.1%) fewer non-cerebrovascular patients over the 2-year period. Our CDST would have ordered CTA for 18 (78.3%) of the recurrent stroke patients in the sample.

CONCLUSIONS

Our CDST could enhance CTA utilization in the ED for suspected TIA patients, and facilitate guideline-based stroke care. Use of our CDST would increase the number of TIA patients receiving CTA before ED discharge (rather than later at TIA units) and reduce the burden of imaging stroke mimics in radiological departments.

Validation of a proteomic biomarker panel to diagnose minor-stroke and transient ischaemic attack: phase 2 of SpecTRA, a large scale translational study

OBJECTIVE

To validate our previously developed 16 plasma-protein biomarker panel to differentiate between transient ischaemic attack (TIA) and non-cerebrovascular emergency department (ED) patients.

METHOD

Two consecutive cohorts of ED patients prospectively enrolled at two urban medical centers into the second phase of SpecTRA study (training, cohort 2A, n = 575; test, cohort 2B, n = 528). Plasma samples were analyzed using liquid chromatography/multiple reaction monitoring-mass spectrometry. Logistic regression models which fit cohort 2A were validated on cohort 2B.

RESULTS

Three of the panel proteins failed quality control and were removed from the panel. During validation, panel models did not outperform a simple motor/speech (M/S) deficit variable. Post-hoc analyses suggested the measured behaviour of L-selectin and coagulation factor V contributed to poor model performance. Removal of these proteins increased the external performance of a model containing the panel and the M/S variable.

CONCLUSIONS

Univariate analyses suggest insulin-like growth factor-binding protein 3 and serum paraoxonase/lactonase 3 are reliable and reproducible biomarkers for TIA status. Logistic regression models indicated L-selectin, apolipoprotein B-100, coagulation factor IX, and thrombospondin-1 to be significant multivariate predictors of TIA. We discuss multivariate feature subset analyses as an exploratory technique to better understand a panel's full predictive potential.

S100ß, Matrix Metalloproteinase-9, D-dimer, and Heat Shock Protein 70 Are Serologic Biomarkers of Acute Cerebral Infarction in a Mouse Model of Transient MCA Occlusion

Objective

Diagnosing acute cerebral infarction is crucial in determining prognosis of stroke patients. Although many serologic tests for prompt diagnosis are available, the clinical application of serologic tests is currently limited. We investigated whether S100β, matrix metalloproteinase-9 (MMP-9), D-dimer, and heat shock protein 70 (HSP70) can be used as biomarkers for acute cerebral infarction.

Methods

Focal cerebral ischemia was induced using the modified intraluminal filament technique. Mice were randomly assigned to 30-minute occlusion (n=10), 60-minute occlusion (n=10), or sham (n=5) groups. Four hours later, neurological deficits were evaluated and blood samples were obtained. Infarction volumes were calculated and plasma S100β, MMP-9, D-dimer, and HSP70 levels were measured using enzyme-linked immunosorbent assay.

Results

The average infarction volume was 12.32±2.31 mm³ and 46.9±7.43 mm³ in the 30- and 60-minute groups, respectively. The mean neurological score in the two ischemic groups was 1.6±0.55 and 3.2±0.70, respectively. S100β, MMP-9, and HSP70 expressions significantly increased after 4 hours of ischemia (p=0.001). Furthermore, S100β and MMP-9 expressions correlated with infarction volumes (p<0.001) and neurological deficits (p<0.001). There was no significant difference in D-dimer expression between groups (p=0.843). The area under the receiver operating characteristic curve (AUC) showed high sensitivity and specificity for MMP-9, HSP70 (AUC=1), and S100β (AUC=0.98).

Conclusion

S100β, MMP-9, and HSP70 can complement current diagnostic tools to assess cerebral infarction, suggesting their use as potential biomarkers for acute cerebral infarction.

Verification of a proteomic biomarker panel to diagnose minor stroke and transient ischaemic attack: phase 1 of SpecTRA, a large scale translational study

OBJECTIVE

To derive a plasma biomarker protein panel from a list of 141 candidate proteins which can differentiate transient ischaemic attack (TIA)/minor stroke from non-cerebrovascular (mimic) conditions in emergency department (ED) settings.

DESIGN

Prospective clinical study (#NCT03050099) with up to three timed blood draws no more than 36 h following symptom onset. Plasma samples analysed by multiple reaction monitoring-mass spectrometry (MRM-MS).

PARTICIPANTS

Totally 545 participants suspected of TIA enrolled in the EDs of two urban medical centres.

OUTCOMES

90-day, neurologist-adjudicated diagnosis of TIA informed by clinical and radiological investigations.

RESULTS

The final protein panel consists of 16 proteins whose patterns show differential abundance between TIA and mimic patients. Nine of the proteins were significant univariate predictors of TIA [odds ratio (95% confidence interval)]: L-selectin [0.726 (0.596-0.883)]; Insulin-like growth factor-binding protein 3 [0.727 (0.594-0.889)]; Coagulation factor X [0.740 (0.603-0.908)]; Serum paraoxonase/lactonase 3 [0.763 (0.630-0.924)]; Thrombospondin-1 [1.313 (1.081-1.595)]; Hyaluronan-binding protein 2 [0.776 (0.637-0.945)]; Heparin cofactor 2 [0.775 (0.634-0.947)]; Apolipoprotein B-100 [1.249 (1.037-1.503)]; and von Willebrand factor [1.256 (1.034-1.527)]. The scientific plausibility of the panel proteins is discussed.

CONCLUSIONS

Our panel has the potential to assist ED physicians in distinguishing TIA from mimic patients.

Differential Proteomics for Distinguishing Ischemic Stroke from Controls: a Pilot Study of the SpecTRA Project

A diagnostic blood test for stroke is desirable but will likely require multiple proteins rather than a single “troponin.” Validating large protein panels requires large patient numbers. Mass spectrometry (MS) is a cost-effective tool for this task. We compared differences in the abundance of 147 protein markers to distinguish 20 acute cerebrovascular syndrome (ACVS) patients who presented to the Emergency Department of one urban hospital within < 24 h from onset) and from 20 control patients who were enrolled via an outpatient neurology clinic. We targeted proteins from the stroke literature plus cardiovascular markers previously studied in our lab. One hundred forty-one proteins were quantified using MS, 8 were quantified using antibody protein enrichment with MS, and 32 were measured using ELISA, with some proteins measured by multiple techniques. Thirty proteins (4 by ELISA and 26 by the MS techniques) were differentially abundant between mimic and stroke after adjusting for age in robust regression analyses (FDR < 0.20). A logistic regression model using the first two principal components of the proteins significantly improved discrimination between strokes and controls compared to a model based on age alone (p < 0.001, cross-validated AUC 0.93 vs. 0.78). Significant proteins included markers of inflammation (47%), coagulation (40%), atrial fibrillation (7%), neurovascular unit injury (3%), and other (3%). These results suggest the potential value of plasma proteins as biomarkers for ACVS diagnosis and the role of plasma-based MS in this area.

Elevated levels of D-dimers increase the risk of ischaemic and haemorrhagic stroke

Elevated D-dimer levels are reportedly associated with coronary artery disease. It was the study objective to investigate the association of baseline D-dimer levels with strokes that occurred in the European Prospective Investigation into Cancer and Nutrition-Italy cohort. Using a nested case-cohort design, a centre-–stratified sample of 832 subjects (66 % women, age 35–71) was selected as subcohort and compared with 289 strokes in a mean follow-up of nine years. D-dimers were measured by an automated latex-enhanced immunoassay (HemosIL-IL). The multivariable hazard ratios were estimated by a Cox regression model using Prentice method. Individuals with elevated D-dimer levels had significantly higher risk of incident stroke. It was evident from the second quartile (D-dimers > 100 ng/ml) and persisted almost unchanged for higher D-dimers (hazard ratio [HR] 2.10, 95 % confidence interval [CI]: 1.28–3.47; 2.42, 95 %CI: 1.44–4.09 and 2.10, 95 %CI: 1.27–3.48 for the second, third or fourth quartile compared with the lowest quartile, respectively). The association was independent of several confounders, including triglycerides and C-reactive protein. No differences were observed in men and women (P for interaction= 0.46), in hypertensive or non-hypertensive subjects (P for interaction= 0.88) or in subjects with low (< 1 mg/l) or elevated (≥ 1 mg/l) C-reactive protein (P for interaction=0.35). After stratification for stroke type, the hazard ratio for every standard deviation increase was statistically significant both for ischaemic (1.21; 95 %CI: 1.01 to 1.45) and haemorrhagic (1.24; 95 %CI: 1.00 to 1.65) strokes. In conclusion, our data provide clear evidence that elevated levels of D-dimers are potential risk factors not only for ischaemic but also for haemorrhagic strokes.

Exploring phlebotomy technique as a pre-analytical factor in proteomic analyses by mass spectrometry

Multiple reaction monitoring mass spectrometry (MRM-MS) is an emerging technology for blood biomarker verification and validation; however, the results may be influenced by pre-analytical factors. This exploratory study was designed to determine if differences in phlebotomy techniques would significantly affect the abundance of plasma proteins in an upcoming biomarker development study. Blood was drawn from 10 healthy participants using four techniques: (1) a 20-gauge IV with vacutainer, (2) a 21-gauge direct vacutainer, (3) an 18-gauge butterfly with vacutainer, and (4) an 18-gauge butterfly with syringe draw. The abundances of a panel of 122 proteins (117 proteins, plus 5 matrix metalloproteinase (MMP) proteins) were targeted by LC/MRM-MS. In addition, complete blood count (CBC) data were also compared across the four techniques. Phlebotomy technique significantly affected 2 of the 11 CBC parameters (red blood cell count, p = 0.010; hemoglobin concentration, p = 0.035) and only 12 of the targeted 117 proteins (p < 0.05). Of the five MMP proteins, only MMP7 was detectable and its concentration was not significantly affected by different techniques. Overall, most proteins in this exploratory study were not significantly influenced by phlebotomy technique; however, a larger study with additional patients will be required for confirmation.

GFAP and antibodies against NMDA receptor subunit NR2 as biomarkers for acute cerebrovascular diseases

We studied whether the serum levels of glial fibrillary acidic protein (GFAP) and of antibodies against the N-methyl-d-aspartate receptor subunit NR2 (NR2 R_NMDA) can discriminate between intracerebral haemorrhage (ICH) and ischaemic stroke (IS) in stroke patients. We prospectively recruited patients with suspected stroke (72 confirmed) and 52 healthy controls. The type of brain lesion (ICH or IS) was established using brain imaging. The levels of GFAP and of antibodies against NR2 R_NMDA were measured in blood samples obtained within 12 hrs after stroke onset and 24, 48 and 72 hrs and 1 and 2 weeks later using ELISA immunoassay. Improvement in diagnostic performance was assessed in logistic regression models designed to predict the diagnosis and the type of stroke. GFAP peaks early during haemorrhagic brain lesions (at significantly higher levels), and late in ischaemic events, whereas antibodies against NR2 R_NMDA have significantly higher levels during IS at all time-points. Neither of the two biomarkers used on its own could sufficiently discriminate patients, but when they are used in combination they can differentiate at 12 hrs after stroke, between ischaemic and haemorrhagic stroke with a sensitivity and specificity of 94% and 91%, respectively.

Novel inflammatory biomarkers and their correlation to Chlamydia pneumoniae titres in acute ischemic stroke

BACKGROUND

Young stroke patients constitute 15%-30% of all stroke patients in India as against 3.0%-8.5% reported from the West. The mechanisms for stroke in the young may include unconventional risk factors such as infections. We aimed to investigate the role (if any) of Chlamydia pneumoniae antibodies in young patients with acute ischemic stroke (AIS). Several proinflammatory cytokines and biomarkers are released early after the onset of brain ischemia. We assessed the role of heat shock protein (hsp) 65, neopterin, and myeloperoxidase upregulation after AIS in predicting stroke severity. We also assessed relationship of upregulated inflammatory biomarkers with C pneumoniae antibody titres (IgG, IgA, and IgM).

METHODS

Eighty acute stroke patients and healthy age- and sex-matched controls were recruited. Blood samples were drawn within 1 week from the onset of stroke. Detection of IgA, IgG, and IgM antibodies to C pneumoniae was done with a validated microimmunofluorescence technique from 5 mL of serum in all subjects. Inflammatory biomarkers such as neopterin, myeloperoxidase and hsp 65 were estimated with sandwich enzyme linked immunosorbent assay (ELISA) method.

RESULTS

hsp 65 and neopterin were significantly elevated in all stroke patients with respect to healthy controls (odds ratio [OR], 4.9; 95% confidence interval [CI], 23.5-67.8; P = .001 and OR, 4.4; 95% CI, 2.08-9.4; P = .04, respectively). Eighty-one percent of cases were seropositive for IgA versus 32% of controls (P = .003), and IgG was positive in 52.7% versus 17.3% of controls (P = .05). Myeloperoxidase levels were similar in patients and controls. Correlation and multiple regression indicated a high level of predictability and sensitivity of hsp 65 to IgA. C. pneumoniae antibody titres when all other variables were constant (F [4,90] = -6.8, P = .001). Patients with high NIHSS scores (>15) had elevated levels of hsp 65 (mean, 13.2 ng/mL) suggesting correlation with stroke severity.

CONCLUSIONS

The study demonstrated high levels of hsp 65 and neopterin levels in AIS correlated to significantly elevated IgA titres of C pneumoniae. Elevated levels of hsp 65 were associated with stroke severity.

Serum protein S100β is a diagnostic biomarker for distinguishing posterior circulation stroke from vertigo of nonvascular causes

BACKGROUND

In patients presenting with acute vertigo or dizziness, identifying the posterior fossa stroke as the underlying cause can be a major challenge. We therefore evaluated the serum biomarkers for the differential diagnosis of nonvascular vertigo and posterior circulation stroke.

METHODS

Of a total of 80 patients, 31 patients had an ischemic stroke in the posterior circulation and 12 infratentorial hemorrhage. Findings in these patients were compared with those in 22 patients with vertigo of nonvascular origin and 15 matched control patients without neurological symptoms. Blood samples drawn <24 h after symptom onset were analyzed for S100 calcium-binding protein B (S100β), matrix metalloproteinase 9 (MMP-9), soluble vascular cellular adhesion molecule-1 (sVCAM-1), and glial fibrillary acidic protein (GFAP).

RESULTS/CONCLUSION

Serum levels of S100β were significantly higher in stroke patients than in nonvascular vertigo patients. Serum concentrations of MMP-9 tended to be higher in stroke patients, whereas no significant differences among groups were found for sVCAM-1 and GFAP. Receiver-operating characteristic analysis revealed a sensitivity of 94.4% and a specificity of 31.8% for detecting stroke in patients presenting with vertigo for S100β. S100β may serve as a biomarker for distinguishing between vertigo of vascular causes and nonvascular, acute vertigo.

A bioclinical pattern for the early diagnosis of cardioembolic stroke

Background and Scope. Early etiologic diagnosis of ischemic stroke subtype guides acute management and treatment. We aim to evaluate if plasma biomarkers can predict stroke subtypes in the early phase from stroke onset. Methods. Plasma N-terminal prohormone of brain natriuretic peptide (NT-proBNP), D-dimer, C-reactive protein, serum albumin, and globulin levels have been investigated in 114 consecutive patients presenting at the emergency room within 6 hours of the ischemic stroke onset. Plasma levels of biomarkers have been correlated with stroke aetiology (based on TOAST criteria) by multivariable logistic regression analysis, adjusted for several covariates. Results. Of the 114 patients, 34 (30%) had cardioembolic stroke, 27 (23%) atherothrombotic stroke, 19 (17%) lacunar stroke, and 34 (30%) stroke of undetermined origin. Patients with cardioembolic stroke had significantly higher levels of NT-proBNP and lower globulin/albumin (G/A) ratio compared with the other subgroups. At multiple logistic regression NT-proBNP > 200 pg/mL, G/A ratio > 0.70, and NIHSS score were independent predictors of cardioembolic stroke with high accuracy of the model, either including (AUC, 0.91) or excluding (AUC, 0.84) atrial fibrillation. Conclusions. A prediction model that includes NT-proBNP, G/A ratio, and NIHSS score can be useful for the early etiologic diagnosis of ischemic stroke.

Predictive value of circulating interleukin-6 and heart-type fatty acid binding protein for three months clinical outcome in acute cerebral infarction: multiple blood markers profiling study

Introduction

There is no single blood marker for predicting the prognosis in ischemic stroke. A combination of multiple blood markers may enhance the ability to predict long-term outcome following ischemic stroke.

Methods

Blood concentrations of neuronal markers (neuron-specific enolase, visinin-like protein 1, heart type fatty acid binding protein (hFABP) and neuroglobin), astroglial markers (S100B and glial fibrillary acidic protein), inflammatory markers (IL-6, TNF-α, and C-reactive protein), blood-brain barrier marker (matrix metalloproteinase 9), and haemostatic markers (D-dimer and PAI-1) were measured within 24 hours after stroke onset. The discrimination and reclassification for favorable and poor outcome were compared after adding individual or a combination of blood markers to the clinical model of stroke outcome.

Results

In multivariate analysis, natural log-transformed (_log) IL-6 (odds ratio (OR): 1.75, 95% CI: 1.25 to 2.25, P = 0.001) and _loghFABP (OR: 3.23, 95% CI: 1.44 to 7.27, P = 0.005) were independently associated with poor outcome. The addition of a single blood marker to the clinical model did not improve the discriminating ability of the clinical model of stroke outcome. However, the addition of the combination of _logIL-6 and _loghFABP to the clinical model showed improved discrimination (area under receiver operating characteristic (AUROC) curve: 0.939 versus 0.910, P = 0.03) and reclassification performance (net reclassification improvement index: 0.18, P = 0.005).

Conclusions

A combination of circulating IL-6 and hFABP level has an additive clinical value for the prediction of stroke outcome.

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.

Limited clinical value of multiple blood markers in the diagnosis of ischemic stroke

OBJECTIVES

No ideal blood marker exists for the diagnosis of ischemic stroke. Combined use of multiple blood markers would enhance the ability of clinical diagnosis of ischemic stroke.

DESIGN AND METHODS

Blood concentrations of neuronal markers (NSE, VSNL-1, hFABP, and Ngb), astroglial markers (S100B and GFAP), inflammatory markers (IL-6 and TNF-α), blood-brain barrier marker (MMP-9), and hemostatic markers (PAI-1) were measured within 6-24 h of stroke onset. The area under the receiver operator characteristic (AUROC) curve of patients with ischemic stroke and stroke-mimic was compared after adding individual or a combination of blood markers to the clinical diagnostic assessment (age, atrial fibrillation, and Face-Arm-Speech Test [FAST]).

RESULTS

Despite acute elevations of blood IL-6, S100B, MMP-9, hFABP, and PAI-1 in univariate analysis, only IL-6, S100B, and MMP-9 were independently associated with ischemic stroke in multivariate analysis. The addition of biomarkers (IL-6, S100B, and MMP-9) did not improve the diagnostic performance of baseline clinical models with added biomarkers versus baseline clinical models alone (AUROC, 0.865 vs. 0.837, p=0.069).

CONCLUSIONS

IL-6, S100B, and MMP-9 markers are elevated in the peripheral blood during the acute phase of ischemic stroke. However, the clinical usefulness of these biomarkers is limited due to low discriminating ability when compared to clinical parameters alone in diagnosis of ischemic stroke.

Cocktail blood biomarkers: prediction of clinical outcomes in patients with acute ischemic stroke

BACKGROUND

Timely prediction of stroke outcomes is important for proper personalized treatment. In the present study, we aimed to develop cocktail blood biomarkers to increase prediction efficiency using a combination of hemostasis, inflammatory and repair-related biomarkers.

METHODS

105 patients suffering from acute ischemic stroke were divided into good outcome group and poor outcome group by modified Rankin Scale (mRS). Cytokines including CD40L, IFN-γ, IL-1α, IL-1β, IL-6, IL-8, IL-17 and TNF-α, as well as hemostasis markers fibrinogen, fibrin degradation products (FDP), D-dimer, tissue plasminogen activator, and plasminogen activation inhibitor-1 in plasma were examined by ELISA. Repair-related biomarker microRNA-210 (miR-210) was measured by real-time PCR. The prediction efficiency was explored by receiver operator characteristic analysis.

RESULTS

We demonstrated that FDP, IL-6 and miR-210 levels were closely associated with mRS in stroke patients. The prediction sensitivity of FDP, IL-6 and miR-210 for stroke outcome was 72.0, 86.7 and 82.5%, respectively. Using a combination of biomarkers including FDP, IL-6 and miR-210, the prognostic sensitivity of ischemic stroke increased to 95.2%.

CONCLUSION

The combination of FDP, IL-6 and miR-210 has a high sensitivity for predicting stroke recovery, it serves as a potential cocktail blood biomarker. It provides a novel approach for stroke prognosis.

Plasma NT-proBNP and white matter hyperintensities in type 2 diabetic patients

Abstract

Elevated plasma N-terminal (NT)-proBNP from the heart as well as white matter hyperintensities (WMH) in the brain predict cardiovascular (CV) mortality in the general population. The cause of poor prognosis associated with elevated P-NT-proBNP is not known but WMH precede strokes in high risk populations. We assessed the association between P-NT-proBNP and WMH or brain atrophy measured with magnetic resonance imaging (MRI) in type 2 diabetic patients, and age-matched controls.

Methods and results

We measured P-NT-proBNP(ng/l) in 20 diabetic patients without prior stroke but with(n = 10) or without(n = 10) asymptomatic coronary artery disease(CAD) in order to include patients with a wide-ranging CV risk profile. All patients and 26 controls had a 3D MRI and brain volumes(ml) with WMH and brain parenchymal fraction(BPF), an indicator of brain atrophy, were determined.

P-NT-proBNP was associated with WMH in linear regression analysis adjusted for CV risk factors(r = 0.94, p = 0.001) and with BPF in univariate analysis(r = 0.57, p = 0.009). Patients divided into groups of increased P-NT-proBNP levels were paralleled with increased WMH volumes(geometric mean[SD];(2.86[5.11] ml and 0.76[2.49] ml compared to patients with low P-NT-proBNP 0.20[2.28] ml, p = 0.003)) and also when adjusted for age, sex and presence of CAD(p = 0.017). The association was strengthened by CV risk factors and we did not find a common heart or brain specific driver of both P-NT-proBNP and WMH. Patients and particular patients with CAD had higher WMH, however no longer after adjustment for age and sex.

Conclusion

P-NT-proBNP was associated with WMH in type 2 diabetic patients, suggesting a linkage between heart and brain disease.

Fibrin D-dimer, tissue-type plasminogen activator, von Willebrand factor, and risk of incident stroke in older men

BACKGROUND AND PURPOSE

Abnormalities in blood coagulation and the fibrinolytic system have been associated with increased risk of stroke, but few prospective studies have studied the associations in older adults. We have examined the associations between fibrin D-dimer, tissue-type plasminogen activator, and von Willebrand factor (vWF) and risk of stroke in older men and examined their predictive roles separately in normotensive and hypertensive men.

METHODS

Prospective study of 3358 men aged 60 to 79 years with no previous diagnosis of myocardial infarction or stroke and without atrial fibrillation followed-up for an average of 9 years, during which there were 187 incident stroke events.

RESULTS

Increased levels of D-dimer and vWF were associated with significantly increased risk of major stroke events after adjustment for potential confounders, including systolic blood pressure (adjusted hazard ratios and 95% confidence interval per standard deviation increase in D-dimer and vWF were 1.24 [95% confidence interval, 1.08-1.44] and 1.25 [95% confidence interval, 1.09-1.45], respectively). No associations were seen with tPA after adjustment. The positive associations between D-dimer and vWF and incident stroke remained after additional adjustment for markers of inflammation (C-reactive protein, IL-6). D-dimer was associated with stroke in both normotensive and hypertensive men; vWF showed stronger associations in normotensive than in hypertensive men (test for interaction: P=0.52 for D-dimer; P<0.01 for vWF).

CONCLUSIONS

Fibrin D-dimer and vWF are associated with increased risk of stroke in older men. These associations were not explained by their associations with inflammation. D-dimer may be a useful marker to identify those at high risk for stroke among hypertensive men.

Cerebrospinal fluid catecholamine levels as predictors of outcome in subarachnoid hemorrhage

OBJECTIVE

Subarachnoid hemorrhage (SAH) is associated with marked sympathetic activation at the time of ictus. The purpose of this study is to determine whether early central catecholamine levels measured from cerebrospinal fluid (CSF) relate to outcome in patients with SAH.

METHODS

Observational study of consecutive SAH grade 3-5 patients who underwent ventriculostomy placement, but did not undergo open craniotomy for aneurysm obliteration. CSF samples were obtained during the first 48 h following symptom onset and assayed for catecholamine levels. Statistical analyses were performed to determine whether the levels predicted mortality by day 15 or mortality/disability by day 30.

RESULTS

For the 102 patients included, mean age was 58, and 73% were female - 21% experienced day-15 mortality, and 32% experienced mortality/disability by day 30. Early mortality was related to Hunt-Hess (H/H) grade (p < 0.001), neurogenic cardiomyopathy (NC) (p = 0.003), cerebral infarction (p = 0.001), elevated intracranial pressure (ICP) (p = 0.029), epinephrine (EPI) level (p = 0.002) and norepinephrine/3,4-dihydroxyphenylglycol (NE/DHPG) ratio (p = 0.003). Mortality/disability was related to H/H grade (p < 0.001), NC (p = 0.018), infarction (p < 0.001), elevated ICP (p = 0.002), EPI (p = 0.004) and NE/DHPG (p = 0.014). Logistic regression identified age [OR 1.09 (95% CI 1.01-1.17)], H/H grade [9.52 (1.19-77)], infarction [10.87 (1.22-100)], ICP elevation [32.26 (2-500)], EPI [1.06 (1.01-1.10)], and (inversely) DHPG [0.99 (0.99-1.00)] as independent predictors of early mortality. For mortality/disability, H/H grade [OR 21.74 (95% CI 5.62-83)], ICP elevation [18.52 (1.93-166)], and EPI [1.05 (1.02-1.09)] emerged as independent predictors. Proportional-hazards analysis revealed age [HR 1.041 (95% CI 1.003-1.08)], H/H grade [6.9 (1.54-31.25)], NC [4.31 (1.5-12.35)], and EPI [1.032 (1.009-1.054)] independently predicted early mortality.

CONCLUSIONS

CSF catecholamine levels are elevated in SAH patients who experience early mortality or disability. EPI may potentially serve as useful index of outcome in this population of patients with SAH.

Hoover's sign for the diagnosis of functional weakness: a prospective unblinded cohort study in patients with suspected stroke

OBJECTIVE

Hoover's sign - weakness of voluntary hip extension with normal involuntary hip extension during contralateral hip flexion against resistance - is a commonly used sign in the diagnosis of functional weakness of the lower limb. However, little is known about the performance of this sign in clinical practice.

METHODS

Hoover's sign was tested as part of the diagnostic work-up of 337 patients presenting to hospital with suspected stroke. We made a gold-standard diagnosis of stroke, functional disorder, or other diagnosis based on clinical history and examination, imaging and clinical follow-up. We calculated the sensitivity, specificity, positive and negative predictive values of Hoover's sign for a diagnosis of functional weakness in patients who presented with leg weakness.

RESULTS

We consecutively recruited 337 consecutive patients with suspected stroke, 124 of whom presented with leg weakness. 8 of these patients had a diagnosis of functional disorder. The sensitivity of Hoover's sign for a diagnosis of functional weakness in those who presented with leg weakness was 63% (95% CI: 24 to 91), and the specificity was 100% (95% CI: 97 to 100).

CONCLUSIONS

In this cohort, Hoover's sign was moderately sensitive and very specific for a diagnosis of functional weakness. Further studies are required to assess inter-observer variability and performance of the test in larger numbers of patients with functional weakness.