Blood biomarkers of ischemic stroke

A scoping review of pre-hospital technology to assist ambulance personnel with patient diagnosis or stratification during the emergency assessment of suspected stroke

BACKGROUND

Pre-hospital identification of key subgroups within the suspected stroke population could reduce delays to emergency treatment. We aimed to identify and describe technology with existing proof of concept for diagnosis or stratification of patients in the pre-hospital setting.

METHODS

A systematic electronic search of published literature (from 01/01/2000 to 06/06/2019) was conducted in five bibliographic databases. Two reviewers independently assessed eligibility of studies or study protocols describing diagnostic/stratification tests (portable imaging/biomarkers) or technology facilitating diagnosis/stratification (telemedicine) used by ambulance personnel during the assessment of suspected stroke. Eligible descriptions required use of tests or technology during the actual assessment of suspected stroke to provide information directly to ambulance personnel in the pre-hospital setting. Due to study, intervention and setting heterogeneity there was no attempt at meta-analysis.

RESULTS

2887 articles were screened for eligibility, 19 of which were retained. Blood biomarker studies (n = 2) were protocols of prospective diagnostic accuracy studies, one examining purines and the other a panel of known and novel biomarkers for identifying stroke sub-types (versus mimic). No data were yet available on diagnostic accuracy or patient health outcomes. Portable imaging studies (n = 2) reported that an infrared screening device for detecting haemorrhages yielded moderate sensitivity and poor specificity in a small study, whilst a dry-EEG study to detect large vessel occlusion in ischaemic stroke has not yet reported results. Fifteen evaluations of pre-hospital telemedicine were identified (12 observational and 3 controlled comparisons) which all involved transmission of stroke assessment data from the pre-hospital setting to the hospital. Diagnosis was generally comparable with hospital diagnosis and most telemedicine systems reduced time-to-treatment; however, it is unknown whether this time saving translated into more favourable clinical outcomes. Telemedicine systems were deemed acceptable by clinicians.

CONCLUSIONS

Pre-hospital technologies to identify clinically important subgroups amongst the suspected stroke population are in development but insufficient evidence precludes recommendations about routine use in the pre-hospital setting. Multi-centre diagnostic accuracy studies and clinical utility trials combining promising technologies are warranted.

Association of biomarker S100B and cerebral oximetry with neurological changes during carotid endarterectomy performed in awake patients

Background: This study attempted to correlate neurological symptoms in awake patients undergoing carotid endarterectomy (CEA) under local anaesthesia (LA) with serum concentration of S100B protein and measurement of cerebral oximetry with near-infrared spectroscopy (NIRS). Patients and methods: A total of 64 consecutive CEAs in 60 patients operated under LA during an 18-month period were prospectively evaluated. A cerebral oximeter was used to measure cerebral oxygen saturation (rSO₂) before and after cross-clamping along with serum concentration of the S100B protein. Selective shunting was performed when neurological changes occurred, regardless of NIRS. Neurological deterioration occurred (neurological symptoms group) in 7 (10.9 %) operations. In 57 (89.1 %) operations, the patients were neurologically stable (no neurological symptoms group). Results: The neurological symptoms that occurred after clamping correlated with an increase in the serum level of S100B (P = .040). The cut-off of 22.5 % of S100B increase was determined to be optimal for identifying patients with neurological symptoms. There was no correlation between rSO₂ decline and neurological symptoms (P = .675). Two (3.1 %) perioperative strokes occurred. Conclusions: We found a correlation between neurological symptoms and serum S100B protein increase. However, because of the long evaluation time of serum S100B, this monitoring technique cannot be performed during CEA.

Predictors of Postthrombolysis Outcome and Symptomatic Postthrombolysis Hemorrhage following Intravenous Thrombolysis with Alteplase for Acute Ischemic Stroke

Background  Thrombolysis improves the outcome in acute ischemic stroke (AIS), albeit with an increased risk of symptomatic intracranial hemorrhage (sICH). Biomarkers to find patients at risk of sICH, and guide treatment and prognosis would be valuable. Methods  Consecutive patients of AIS thrombolysed between February 2017 and September 2019 at Calcutta National Medical College were studied prospectively for sICH and outcome at 6-month follow-up. We identified the independent risk factors for unfavorable outcomes, mortality, and sICH using multivariate analysis. Prethrombolysis and 24-hour postthrombolysis fibrinogen levels were estimated to evaluate its biomarker role. Results  Out of 180 AIS patients admitted during the study period, 60 patients were thrombolysed. Door to needle time was <3 hours among 24 patients and 3 to 4.5 hours among 36 patients. Favorable outcomes occurred among 76.67% and sICH occurred among 13.33% patients. Upper tertile of National Institute of Health Stroke Scale (NIHSS) had the highest adjusted odds for sICH (17.5 [95% confidence intervals=1.7-178.44]). Total anterior circulation stroke had the highest adjusted odds for unfavorable outcome (19.11 [3.9-92.6]). Following thrombolysis, the mean (standard deviation) fibrinogen level of 449.27 (32.87) decreased 7% to postthrombolysis level of 420 (20.5; p< 0.0001). Higher tertiles of fibrinogen levels had progressively increasing odds for morbidity and sICH. Conclusion  Congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke (double weight), i.e., CHADS2 score >2, low ejection fraction, the occurrence of total anterior circulation stroke and higher mean arterial blood pressure, blood glucose level, NIHSS score, and fibrinogen at admission were the common risk factors significantly predicting postthrombolysis sICH and morbidity. Antiplatelet and anticoagulant therapy, lower ASPECT (Alberta Stroke Program Early CT Score), and higher SEDAN scores also predicted sICH . Fibrinogen levels were significantly higher among those developing sICH and having unfavorable outcome. The performance of thrombolysis within 3 hours or between 3 and 4.5 hours after symptom onset did not affect morbidity, mortality, or the occurrence of sICH.

The elevation of S100B and downregulation of circulating miR-602 in the sera of ischemic stroke (IS) patients: the emergence of novel diagnostic and prognostic markers

Ischemic stroke (IS) is a major cause of mortality and disability. However, no reliable prognostic or diagnostic biomarker has been utilized to date. Here, we have evaluated the serum S100B concentration and miR-602 expression as potential biomarkers for IS. Fifty-two IS patients and 52 age- and sex-matched healthy volunteers were enrolled. Blood samples were collected from all patients at the time of admission, 24 and 48 h later, at the time of discharge, and 3 months later. Real-time (RT) PCR was used to measure the serum level of miR602. We also measured the serum concentration of S100B using ELISA. As compared with healthy subjects, IS patients had a higher level of serum S100B and lower serum miR-602. ROC curve analyses revealed that miR-602 (AUC = 0.8168; P < 0.0001) and S100B (AUC = 0.8699; P < 0.0001) had acceptable ability to differentiate between IS patients from healthy subjects. Furthermore, serum S100B was a reliable predictor of the survival outcome at 3 months (P = 0.021). The expression of miR-602 was significantly higher in patients with bigger NIHSS scores. The lower levels of miR-602 and higher concentration of S100B in the sera of IS patients could be associated with clinically significant diagnostic utilities. S100B could be also introduced as a reliable prognostic marker for stroke and implemented in future research.

RNA expression studies in stroke: what can they tell us about stroke mechanism?

PURPOSE OF REVIEW

Diagnosis of stroke and understanding the mechanism of stroke is critical to implement optimal treatment. RNA expressed in peripheral blood cells is emerging as a precision biomarker to aid in stroke diagnosis and prediction of stroke cause. In this review, we summarize available data regarding the role of RNA to predict stroke, the rationale for these changes, and a discussion of novel mechanistic insight and clinical applications.

RECENT FINDINGS

Differences in RNA gene expression in blood have been identified in patients with stroke, including differences to distinguish ischemic from hemorrhagic stroke, and differences between cardioembolic, large vessel atherosclerotic, and small vessel lacunar stroke cause. Gene expression differences show promise as novel stroke biomarkers to predict stroke of unclear cause (cryptogenic stroke). The differences in RNA expression provide novel insight to stroke mechanism, including the role of immune response and thrombosis in human stroke. Important insight to regulation of gene expression in stroke and its causes are being acquired, including alternative splicing, noncoding RNA, and microRNA.

SUMMARY

Improved diagnosis of stroke and determination of stroke cause will improve stroke treatment and prevention. RNA biomarkers show promise to aid in the diagnosis of stroke and cause determination, as well as providing novel insight to mechanism of stroke in patients. While further study is required, an RNA profile may one day be part of the stroke armamentarium with utility to guide acute stroke therapy and prevention strategies and refine stroke phenotype.

Red Cell Distribution Width (RDW) Index as a Predictor of Severity of Acute Ischemic Stroke: A Correlation Study

Introduction:

Globally, stroke is one of the leading causes of death and disability-adjusted life-years (DALYs). The red cell distribution width (RDW) is a readily available and inexpensive test which is done routinely as a part of complete blood count in these patients.

Objective:

In this study, we tried to correlate the RDW with severity of acute ischemic stroke (AIS).

Methods:

Patients presenting to emergency department (ED) within 24 hours of the onset of clinical signs and symptoms suggestive of AIS were assessed for Glasgow Coma Scale (GCS) and National Institutes of Health Stroke Scale (NIHSS) score followed by non-contrast computed tomography (NCCT) scan. RDW value for all the patients who were included in the study were co-related with the severity of the stroke.

Results:

The median (IQR) RDW in the patients with minor stroke on the basis of GCS was 13.5 (13.3–13.5), moderate stroke was 13.8 (13.5–14.4) and with severe stroke was 15.4 (15.1–15.6) (p < 0.001). The median (IQR) RDW in the patients with minor stroke on the basis of NIHSS score was 13.4 (13.2 – 13.6), moderate stroke was 13.8 (13.5–14.3), and moderate to severe stroke was 14.7 (14.5–15.3) and with severe stroke was 15.5 (15.1–15.7) (p < 0.001). The median RDW in patients who were alive was 13.8 (13.5–15.1) and in patients who expired was 15.5 (14.5–15.7) (p = 0.048).

Conclusion:

Based on the findings of this study, RDW index has statistically significant correlation with the severity of AIS. So it can potentially be an important parameter to predict the prognosis of AIS patients.

Blood Biomarkers for Stroke Diagnosis and Management

Biomarkers are objective indicators used to assess normal or pathological processes, evaluate responses to treatment and predict outcomes. Many blood biomarkers already guide decision-making in clinical practice. In stroke, the number of candidate biomarkers is constantly increasing. These biomarkers include proteins, ribonucleic acids, lipids or metabolites. Although biomarkers have the potential to improve the diagnosis and the management of patients with stroke, there is currently no marker that has demonstrated sufficient sensitivity, specificity, rapidity, precision, and cost-effectiveness to be used in the routine management of stroke, thus highlighting the need for additional work. A better standardization of clinical, laboratory and statistical procedures between centers is indispensable to optimize biomarker performance. This review focuses on blood biomarkers that have shown promise for translation into clinical practice and describes some newly reported markers that could add to routine stroke care. Avenues for the discovery of new stroke biomarkers and future research are discussed. The description of the biomarkers is organized according to their expected application in clinical practice: diagnosis, treatment decision, and outcome prediction.

Cerebral Small Vessel Disease (CSVD) - Lessons From the Animal Models

Cerebral small vessel disease (CSVD) refers to a spectrum of clinical and imaging findings resulting from pathological processes of various etiologies affecting cerebral arterioles, perforating arteries, capillaries, and venules. Unlike large vessels, it is a challenge to visualize small vessels in vivo, hence the difficulty to directly monitor the natural progression of the disease. CSVD might progress for many years during the early stage of the disease as it remains asymptomatic. Prevalent among elderly individuals, CSVD has been alarmingly reported as an important precursor of full-blown stroke and vascular dementia. Growing evidence has also shown a significant association between CSVD's radiological manifestation with dementia and Alzheimer's disease (AD) pathology. Although it remains contentious as to whether CSVD is a cause or sequelae of AD, it is not far-fetched to posit that effective therapeutic measures of CSVD would mitigate the overall burden of dementia. Nevertheless, the unifying theory on the pathomechanism of the disease remains elusive, hence the lack of effective therapeutic approaches. Thus, this chapter consolidates the contemporary insights from numerous experimental animal models of CSVD, to date: from the available experimental animal models of CSVD and its translational research value; the pathomechanical aspects of the disease; relevant aspects on systems biology; opportunities for early disease biomarkers; and finally, converging approaches for future therapeutic directions of CSVD.

Discovery of stroke-related blood biomarkers from gene expression network models

BACKGROUND

Identifying molecular biomarkers characteristic of ischemic stroke has the potential to aid in distinguishing stroke cases from stroke mimicking symptoms, as well as advancing the understanding of the physiological changes that underlie the body's response to stroke. This study uses machine learning-based analysis of gene co-expression to identify transcription patterns characteristic of patients with acute ischemic stroke.

METHODS

Mutual information values for the expression levels among 13,243 quantified transcripts were computed for blood samples from 82 stroke patients and 68 controls to construct a co-expression network of genes (separately) for stroke and control samples. Page rank centrality scores were computed for every gene; a gene's significance in the network was assessed according to the differences in their network's pagerank centrality between stroke and control expression patterns. A hybrid genetic algorithm - support vector machine learning tool was used to classify samples based on gene centrality in order to identify an optimal set of predictor genes for stroke while minimizing the number of genes in the model.

RESULTS

A predictive model with 89.6% accuracy was identified using 6 network-central and differentially expressed genes (ID3, MBTPS1, NOG, SFXN2, BMX, SLC22A1), characterized by large differences in association network connectivity between stroke and control samples. In contrast, classification models based solely on individual genes identified by significant fold-changes in expression level provided lower predictive accuracies: < 71% for any single gene, and even models with larger (10-25) numbers of gene transcript biomarkers gave lower predictive accuracies (≤ 82%) than the 6 network-based gene signature classification. miRNA:mRNA target prediction computational analysis revealed 8 differentially expressed micro-RNAs (miRNAs) that are significantly associated with at least 2 of the 6 network-central genes.

CONCLUSIONS

Network-based models have the potential to identify a more statistically robust pattern of gene expression typical of acute ischemic stroke and to generate hypotheses about possible interactions among functionally relevant genes, leading to the identification of more informative biomarkers.

A Pilot Proof-Of-Principle Analysis Demonstrating Dielectrophoresis (DEP) as a Glioblastoma Biomarker Platform

Extracellular vesicles (EVs) are small, membrane-bound particles released by all cells that have emerged as an attractive biomarker platform. We study the utility of a dielectrophoretic (DEP) micro-chip device for isolation and characterization of EVs derived from plasma specimens from patients with brain tumors. EVs were isolated by DEP chip and subjected to on-chip immunofluorescence (IF) staining to determine the concentration of glial fibrillary acidic protein (GFAP) and Tau. EVs were analyzed from the plasma samples isolated from independent patient cohorts. Glioblastoma cell lines secrete EVs enriched for GFAP and Tau. These EVs can be efficiently isolated using the DEP platform. Application of DEP to clinical plasma samples afforded discrimination of plasma derived from brain tumor patients relative to those derived from patients without history of brain cancer. Sixty-five percent (11/17) of brain tumor patients showed higher EV-GFAP than the maximum observed in controls. Ninety-four percent (16/17) of tumor patients showed higher EV-Tau than the maximum observed in controls. These discrimination thresholds were applied to plasma isolated from a second, independent cohort of 15 glioblastoma patients and 8 controls. For EV-GFAP, we observed 93% sensitivity, 38% specificity, 74% PPV, 75% NPV, and AUC of 0.65; for EV-Tau, we found 67% sensitivity, 75% specificity 83% PPV, 55% NPV, and AUC of 0.71 for glioblastoma diagnosis. This proof-of-principle study provides support for DEP-IF of plasma EVs for diagnosis of glioblastoma.

MicroRNA Biomarkers in Cerebrospinal Fluid and Serum Reflect Injury Severity in Human Acute Traumatic Spinal Cord Injury

Spinal cord injury (SCI) is a devastating condition with variability in injury mechanisms and neurologic recovery. Spinal cord impairment after SCI is measured and classified by a widely accepted standard neurological examination. In the very acute stages post-injury, however, this examination is extremely challenging (and often impossible) to conduct and has modest prognostic value in terms of neurological recovery. The lack of objective tools to classify injury severity and predict outcome is a barrier for clinical trials and thwarts development of therapies for those with SCI. Biological markers (biomarkers) represent a promising, complementary approach to these challenges because they represent an unbiased approach to classify injury severity and predict neurological outcome. Identification of a suitable panel of molecular biomarkers would comprise a fundamental shift in how patients with acute SCI are evaluated, stratified, and treated in clinical trials. MicroRNA are attractive biomarker candidates in neurological disorders for several reasons, including their stability in biological fluids, their conservation between humans and model mammals, and their tissue specificity. In this study, we used next-generation sequencing to identify microRNA associated with injury severity within the cerebrospinal fluid (CSF) and serum of human patients with acute SCI. The CSF and serum samples were obtained 1-5 days post-injury from 39 patients with acute SCI (24 American Spinal Injury Association Impairment Scale [AIS] A, 8 AIS B, 7 AIS C) and from five non-SCI controls. We identified a severity-dependent pattern of change in microRNA expression in CSF and identified a set of microRNA that are diagnostic of baseline AIS classification and prognostic of neurological outcome six months post-injury. The data presented here provide a comprehensive description of the CSF and serum microRNA expression changes that occur after acute human SCI. This data set reveals microRNA candidates that warrant further evaluation as biomarkers of injury severity after SCI and as key regulators in other neurological disorders.

Novel miRNA PC-5P-12969 in Ischemic Stroke

Circulating microRNAs (miRNAs) have been used effectively as peripheral biomarkers and mechanistic targets for human diseases such as stroke, Alzheimer's, and cancer. The purpose of our study is to determine noninvasive, blood-based early detectable biomarkers for ischemic stroke (IS). Based on our previous global miRNA sequencing study, four miRNAs were previously unreported (novel) in IS condition. Among these, miRNA PC-5P-12969 was exclusively expressed in the IS condition; otherwise, it was not expressed in normal condition, and therefore, we focused on miRNA PC-5P-12969 for further studies. In the present study, we investigated novel miRNA PC-5P-12969 for its expression levels using quantitative real-time PCR assay (qRT-PCR) in an in vitro, oxygen, and glucose deprivation/reoxygenation (OGD/R)-treated mouse primary hippocampal neuronal cells (HT22) and in an in vivo using a photothrombotic stroke model. In an in vitro study of stroke-induced HT22 cells, we found a two fold increase of PC-5P-12969 expression levels, in agreement with our original global miRNA study. In the cerebral cortex of photothrombotic stroke mice, we found significantly upregulated levels of PC-5P-12969 in 4 hours and 1 day post-stroke relative to the control mice. However, we did not find any change in the expression of PC-5P-12969 in the cerebellum (unaffected in IS) of both stroke and control mice. Based on findings from this study, together with our earlier original global microRNA study results, we conclude that PC-5P-12969 is a potential candidate of the peripheral marker and also a drug target for IS. This is the first study validating that the miRNA PC-5P-12969, might be a potential biomarker for IS.

Circulating microparticles as biomarkers of stroke: A focus on the value of endothelial- and platelet-derived microparticles

Stroke is one of the leading causes of mortality and disability worldwide. Numerous pathophysiological mechanisms involving blood vessels, coagulation and inflammation contribute to the vascular occlusion. Perturbations in these pathways can be detected by numerous methods including changes in endoplasmic membrane remodeling and rearrangement leading to the shedding of microparticles (MPs) from various cellular origins in the blood. MPs are small membrane-derived vesicles that are shed from nearly all cells in the body in resting state or upon stimulation. MPs act as biological messengers to transfer information to adjacent and distant cells thus regulating various biological processes. MPs may be important biomarkers and tools for the identification of the risk and diagnosis of cerebrovascular diseases. Endothelial activation and dysfunction and altered thrombotic responses are two of the main features predisposing to stroke. Endothelial MPs (EMPs) have been recognized as both biomarkers and effectors of endothelial cell activation and injury while platelet-derived MPs (PMPs) carry a strong procoagulant potential and are activated in thrombotic states. Therefore, we reviewed here the role of EMPs and PMPs as biomarkers of stroke. Most studies reported high circulating levels of EMPs and PMPs in addition to other cell origins in stroke patients and have been linked to stroke severity, the size of infarction, and prognosis. The identification and quantification of EMPs and PMPs may thus be useful for the diagnosis and management of stroke.

Brain Functional Reserve in the Context of Neuroplasticity after Stroke

Stroke is the second cause of death and more importantly first cause of disability in people over 40 years of age. Current therapeutic management of ischemic stroke does not provide fully satisfactory outcomes. Stroke management has significantly changed since the time when there were opened modern stroke units with early motor and speech rehabilitation in hospitals. In recent decades, researchers searched for biomarkers of ischemic stroke and neuroplasticity in order to determine effective diagnostics, prognostic assessment, and therapy. Complex background of events following ischemic episode hinders successful design of effective therapeutic strategies. So far, studies have proven that regeneration after stroke and recovery of lost functions may be assigned to neuronal plasticity understood as ability of brain to reorganize and rebuild as an effect of changed environmental conditions. As many neuronal processes influencing neuroplasticity depend on expression of particular genes and genetic diversity possibly influencing its effectiveness, knowledge on their mechanisms is necessary to understand this process. Epigenetic mechanisms occurring after stroke was briefly discussed in this paper including several mechanisms such as synaptic plasticity; neuro-, glio-, and angiogenesis processes; and growth of axon.

A SERS nano-tag-based magnetic-separation strategy for highly sensitive immunoassay in unprocessed whole blood

Assay technologies capable of detecting biomarker concentrations in unprocessed whole blood samples are fundamental for applications in medical diagnostics. SERS nano-tags integrated magnetic-separation biosensor (MSB) was realized for the first time for immunoassay in whole blood. The reliability and sensitivity of this method rely, in a large extent, on the quality and properties of the SERS nano-tags. The constructed silicacoated Ag SERS nano-tags as labels were used in a rapid and specific MSB immune sensor to detect Matrix Metalloproteinases 9 (MMP-9) in unprocessed blood samples. With fast screening ability and outstanding sensitivity, we anticipate that this method would greatly promote practical application of stroke-based early-stage cancer diagnosis.

Distinct plasma proteomic changes in male and female African American stroke patients

BACKGROUND

Stroke occurs more often and results in more severe brain injury in African Americans than in Caucasians. The former also exhibit different responses to thrombolytic therapy than the latter do. There is an imminent need for stroke biomarkers for African Americans, who have been underrepresented in biomarker research for stroke diagnosis and prognosis. Proteomics offers sources for protein biomarkers that are not available by other Omics approaches. In this pilot study, plasma proteomes of African American stroke patients were analyzed and compared to that of hypertensive, non-stroke controls.

METHODS

Plasma samples were prepared from whole blood specimens that were collected from stroke patients admitted to Grady Memorial Hospital in Atlanta, and their age- and sex-matched, hypertensive controls from the outpatient clinic. Samples were pooled according to patient groups and sex. Plasma proteins were analyzed with quantitative mass spectrometry. The identified and quantified proteins were compared between stroke and control patients of each sex. Proteins that showed changes in abundances in stroke patients were further analyzed with the assistance of bioinformatics tools for their known biological functions or potential implications in stroke.

RESULTS

A total of 128 annotated proteins were identified. Results of bioinformatic analysis of plasma proteins whose levels were increased in stroke patients showed, as expected, their association with blood coagulation and inflammation processes. Interestingly, a number of proteins showed different or even opposing changes in male and female stroke patients, notably those involved in IL-4 and IL-6 signaling, complement activation, and blood coagulation disorders. For a few proteins that were increased in female but unchanged or decreased in male stroke patients, an association with fibromuscular dysplasia was recognized.

CONCLUSION

Plasma proteins that differ in quantities between stroke patients and controls were readily detected using a simple proteomic approach. Sex-dependent changes and changes that have not been reported for African American stroke patients offer potentially novel biomarkers for stroke in this underserved population.

Multiplexed electrochemical and SERS dual-mode detection of stroke biomarkers: rapid screening with high sensitivity

In this work, a real-time assay for a highly sensitive, label-free, multiplexed electrochemical and surface-enhanced Raman spectroscopic (SERS) detection of stroke biomarkers by neuron-specific enolase (NSE) and S100-β protein was developed using lateral flow devices.

Neuroimaging, serum biomarkers, and patient characteristics as predictors of upper limb functioning 12 weeks after acute stroke: an observational, prospective study

OBJECTIVE

To evaluate the potential of neuroimaging, serum biomarkers, stroke etiology, and clinical characteristics as predictors of upper limb functioning 12 weeks after stroke.

METHODS

This was a prospective, observational study of patients (18-85 years-old) hospitalized due to acute ischemic stroke in the territory of the middle cerebral artery. Patients were hospitalized at a stroke rehabilitation center, where they underwent a standardized rehabilitation program. Clinical, imagiology, laboratory (biomarkers: C-reactive protein, D-dimer, and fibrinogen, and S100 calcium binding protein β [S100β]), and functionality assessments were conducted four different times: within 24 hours, and at 48 hours, 3 weeks, and 12 weeks after acute stroke.

RESULTS

Upper limb functioning at 12 weeks was significantly associated with Alberta Stroke Program Early CT Score (ASPECTS) score (OR:2.012 [CI:1.349-3.000]; P = 0.001) and S100β protein levels (OR:0.997 [CI:0.994-0.999]; P = 0.007). Advanced age was associated with poor upper limb functioning. S100β protein levels < 140.5 ng/L at 48 hours and ASPECTS scores ≥ 7.5 within 24 hours of admission predicted good hand functioning at 12 weeks. Upper limb functioning and general functioning were significantly correlated (P < 0.001), with strong negative correlations (all correlation coefficients ≤-0.586) for all comparisons.

CONCLUSION

ASPECTS score ≥ 8 within 24 hours and S100β protein < 140.5 ng/L at 48 hours predict better upper limb functioning, while advanced age predicts worse upper limb functioning 12 weeks after stroke.

The Serum BDNF Level Offers Minimum Predictive Value for Motor Function Recovery After Stroke

Brain-derived neurotrophic factor (BDNF) plays an important role in neuroplasticity and neurogenesis following ischemic and non-ischemic brain injury. The predictive value of BDNF for short-term outcome after stroke is controversial. The objective of this study was to investigate the relationship among serum BDNF level, fractional anisotropy (FA), and functional outcome during post-acute stroke rehabilitation. Serum BDNF levels were measured on admission to an acute inpatient rehabilitation hospital. The primary functional outcome was functional independence measure (FIM) motor subscore at discharge. The secondary outcome measures were FIM total score at discharge, FIM motor subscore on admission, length of stay in the hospital, and discharge destination. We investigated the relationship among the level of serum BDNF and FA as well as functional outcome measures. Three hundred forty-eight consecutive stroke subjects were included in the analysis. Serum BDNF levels on admission were statistically but not clinically correlated with FIM motor subscore at discharge (r = 0.173, P = 0.001) and FIM total score at discharge (r = 0.155, P = 0.004). Receiver operating characteristic (ROC) analysis of BDNF as a predictor for FIM motor subscore improvement showed low accuracy of prediction with an area under the curve (AUC) of 0.581 (P = 0.026). Serum BDNF significantly correlated with FA in the high FIM motor group (n = 10, r = 0.609, P = 0.031) but not in the low FIM motor group (n = 11, r = - 0.132, P = 0.349). The serum BDNF level alone offers minimum predictive value for recovery of motor function during post-acute rehabilitation. Our findings suggest that serum BDNF level may be correlated with FA.

Effect of Coenzyme Q10 on Expression of UbiAd1 Gene in Rat Model of Local Cerebral Ischemia

The study examined the effect of endogenous lipid-soluble antioxidant coenzyme Q10 on the expression of UbiA gene of prenyltransferase domain-containing protein 1 (UbiAd1) involved in synthesis of vitamin K2 (and probably of coenzyme Q10) on a rat model of ischemic stroke provoked by ligation of the middle cerebral artery in the left hemisphere. Ischemia enhanced expression of mRNA of UbiAd1 gene in both cerebral hemispheres, but the effect was significant only in the contralateral one. The study revealed no effect of intraperitoneal injection of coenzyme Q10 (30 mg/kg) on ischemia-produced elevation of mRNA of UbiAd1 gene. Further studies are needed to assess possible neuroprotective effects of antioxidant coenzyme Q10.

Diagnosis of Hyperacute and Acute Ischaemic Stroke: The Potential Utility of Exosomal MicroRNA-21-5p and MicroRNA-30a-5p

BACKGROUND

Early and accurate diagnosis of ischaemic stroke (IS) requires the use of an optimized biomarker. Exosomal microRNAs have the potential to serve as biomarkers owing to their stability and specificity. We investigated the expression levels of plasma-derived exosomal microRNA-21-5p and microRNA-30a-5p in the different phases of IS.

METHODS

One hundred forty-three patients with IS and 24 non-stroke controls were enrolled. The patients were divided into the following 5 groups: 1 group for the hyperacute phase IS (HIS, within 6 h); two for the acute phase IS (AIS, including days 1-3 and days 4-7); one for the subacute phase IS (SIS, days 8-14); and one for the recovery phase IS (RIS, days >14). Plasma exosomes were isolated using a QIAGEN exoRNeasy kit and examined by transmission electron -microscopy, nanoparticle tracking, and flow cytometry. The expression levels of miRNA-21-5p and miRNA-30a-5p were detected by quantitative real-time polymerase chain reaction.

RESULTS

The plasma exosomal miR-21-5p levels in SIS and RIS were significantly higher than that in controls (p < 0.05 and p < 0.01 respectively). The levels of miR-30a-5p in HIS were significantly higher (p < 0.05) and in AIS (days 1-3) were lower than that in controls (p < 0.05). In AIS (days 1-3), both miRNAs were decreased compared with the HIS group (p = 0.053 and 0.001, respectively). The area under the curve (AUC) of the miR-21-5p was 0.714 for SIS (95% CI 0.570-0.859, p = 0.007), 0.734 for RIS (95% CI 0.596-0.871, p = 0.003); the AUC of the miR-30a-5p was 0.826 for HIS (95% CI 0.665-0.988, p = 0.001), 0.438 for AIS (days 1-3; 95% CI 0.240-0.635, p = 0.516).

CONCLUSIONS

The plasma-derived exosomal miR-21-5p and miRNA-30a-5p in combination are promising biomarkers for diagnosing IS and distinguishing among HIS, SIS, and RIS, especially miRNA-30a-5p for the diagnosis of the HIS phase. Our results provide a new reference for clinicians to apply in early-stage diagnosis and identifies the possible value of biomarkers for IS thrombolysis therapy.

Cell free DNA: A Novel Predictor of Neurological Outcome after Intravenous Thrombolysis and/or Mechanical Thrombectomy in Acute Ischemic Stroke Patients

PURPOSE

Several blood markers have been evaluated in stroke patients, but their role remains limited in clinical practice. This study was designed to evaluate the utility of cell free DNA (cf DNA) in stroke patients undergoing therapeutic intervention in the form of mechanical thrombectomy in acute ischemic stroke patients.

MATERIALS AND METHODS

Twenty-six patients with ischemic stroke who were managed with interventions like intravenous thrombolysis (IVT) and mechanical thrombectomy were recruited consecutively in this study. The cf DNA was extracted by using circulating nucleic acid kit and measured by real-time quantitative PCR assay for β-globin gene. The neurological outcome was measured by modified Rankin scale (mRS) score at three months after the onset of symptoms.

RESULTS

Cf DNA levels correlated with severity of stroke at the time of admission (r=0.421, P=0.032) and poor outcome at three months (r=0.606, P=0.001). Therapeutic intervention in the form of mechanical thrombectomy or IVT was associated with improved outcome in patients with cf DNA <10,000 kilogenome-equivalents/L (P=<0.05).

CONCLUSION

Cf DNA level correlated well with the 3 month outcome in acute ischemic stroke patients. It can be a potential supplementary marker to predict neurological outcome after therapeutic intervention.

Plasma Exosomal miRNA-122-5p and miR-300-3p as Potential Markers for Transient Ischaemic Attack in Rats

Background: Differentiation of transient ischaemic attack (TIA) from ischaemic stroke within the thrombolysis time window is difficult. Although TIA may be diagnosed within this window, the latest imaging technologies are complex and costly. Serum markers, which are non-invasive, rapid and economic, are used for diagnosis and prognosis of various diseases. Exosome-derived miRNA markers for TIA are unknown.

Methods: We examined focal brain ischaemia produced by occlusion of the middle cerebral artery (MCAo) for 5 min, 10 min, and 2 h in rats. Exosomal miRNAs with consistent trends in cerebrospinal fluid (CSF) and plasma were identified by deep sequencing and quantitative real-time polymerase chain reaction (qRT-PCR). The areas under the curve (AUC) of the receiver operating characteristic (ROC) curve were used to evaluate the diagnostic accuracy of these miRNAs for TIA in rats.

Results: Rno-miR-122-5p and rno-miR-300-3p were selected. Plasma exosomal rno-miR-122-5p was significantly downregulated in 10 min ischaemic rats compared with control and 5 min plasma. Plasma exosomal rno-miR-300-3p was significantly upregulated in 5 min ischaemic rats compared with control, 10 min and 2 h rats. Plasma and CSF levels of these miRNAs were correlated. ROC analysis showed high AUC values for rno-miR-122-5p (0.960) and rno-miR-300-3p (0.970) in the 10 and 5 min rats, respectively, compared with controls.

Conclusions: Plasma exosomal rno-miR-122-5p and rno-miR-300-3p may be blood-based TIA biomarkers.

The diagnostic value of microRNA-4787-5p and microRNA-4306 in patients with acute aortic dissection

Acute aortic dissection (AAD) is a life-threatening cardiovascular disease with the high morbidity and mortality. Imaging modalities are the gold standard for the diagnosis of AAD; however, they are not always available in emergency department. Biomarker-assisted diagnosis is important for the early treatment of AAD. The aim of the present study was to identify potential microRNA (miRNA) biomarkers for AAD. Differentially expressed plasma miRNAs between AAD patients and age-matched healthy volunteers were analyzed by miRNA microarray. Quantitative RT-PCR was further performed to verify the expression of selected miRNAs (miR-4787-5p and miR-4306) with an increased number of samples. Receiver operating characteristic (ROC) analysis was used to assess the diagnostic value of miR-4787-5p and miR-4306 as biomarkers for distinguishing AAD. Using TargetScan and miRanda, miR-4787-5p and miR-4306 were selected to predict target gene related to cytokines detecting by dual luciferase assay and western blotting. Nine upregulated and twelve downregulated miRNAs were identified in the circulating plasma of AAD patients. qRT-PCR verified statistically consistent expression of two selected miRNAs with microarray analysis. ROC analyses demonstrated that miR-4787-5p and miR-4306 were specific and sensitive for the early diagnosis of AAD. Bioinformatic predictions and dual luciferase assay suggested that polycystin-1 (PKD1) and transforming growth factor-β1 (TGF-β1) were respectively direct target of miR-4787-5p and miR-4306. Furthermore, the protein expression of the downstream targets of PKD1 and TGF-β1 were significantly reduced following overexpression of miR-4787-5p and miR-4306. These results revealed that miR-4787-5p and miR-4306 could be developed as diagnostic potential biomarkers for AAD, and they could be involved in the pathogenesis of AAD.

Normobaric Hyperoxia Reduces Blood Occludin Fragments in Rats and Patients With Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Damage of the blood-brain barrier (BBB) increases the incidence of neurovascular complications, especially for cerebral hemorrhage after tPA (tissue-type plasminogen activator) therapy. Currently, there is no effective method to evaluate the extent of BBB damage to guide tPA use. Herein, we investigated whether blood levels of tight junction proteins could serve as biomarker of BBB damages in acute ischemic stroke (AIS) in both rats and patients. We examined whether this biomarker could reflect the extent of BBB permeability during cerebral ischemia/reperfusion and the effects of normobaric hyperoxia (NBO) on BBB damage.

METHODS

Rats were exposed to NBO (100% O₂) or normoxia (21% O₂) during middle cerebral artery occlusion. BBB permeability was determined. Occludin and claudin-5 in blood and cerebromicrovessels were measured. Patients with AIS were assigned to oxygen therapy or room air for 4 hours, and blood occludin and claudin-5 were measured at different time points after stroke.

RESULTS

Cerebral ischemia/reperfusion resulted in the degradation of occludin and claudin-5 in microvessels, leading to increased BBB permeability in rats. In blood samples, occludin increased with 4-hour ischemia and remained elevated during reperfusion, correlating well with its loss from ischemic cerebral microvessels. NBO treatment both prevented occludin degradation in microvessels and reduced occludin levels in blood, leading to improved neurological functions in rats. In patients with AIS receiving intravenous tPA thrombolysis, the blood occludin was already elevated when patients arrived at hospital (within 4.5 hours since symptoms appeared) and remained at a high level for 72 hours. NBO significantly lowered the level of blood occludin and improved neurological functions in patients with AIS.

CONCLUSIONS

Blood occludin may be a clinically viable biomarker for evaluating BBB damage during ischemia/reperfusion. NBO therapy has the potential to reduce blood occludin, protect BBB, and improve outcome in AIS patients with intravenous tPA thrombolysis.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02974283.

Stroke Management: An Emerging Role of Nanotechnology

Stroke is among the leading causes of mortality and morbidity worldwide. Stroke incidences and associated mortality are expected to rise to 23 million and 7.8 million, respectively, by 2030. Further, the aging population, imbalanced lifestyles, and environmental factors continue to shift the rate of stroke incidence, particularly in developing countries. There is an urgent need to develop new therapeutic approaches for treating stroke. Nanotechnology is a growing field, offering an encouraging future prospect for medical research in the management of strokes. The world market for nanotechnology derived products is expected to rise manyfold in the coming decades. Different types of nanomaterials such as perfluorocarbon nanoparticles, iron oxide nanoparticles, gold nanoparticles, polymeric nanoparticles, quantum dots, nanospheres, etc. have been developed for the diagnosis as well as therapy of strokes. Today, nanotechnology has also been integrated with stem cell therapy for treating stroke. However several obstacles remain to be overcome when using such nanomaterials for treating stroke and other neurological diseases.

Higher neutrophil counts and neutrophil-to-lymphocyte ratio predict prognostic outcomes in patients after non-atrial fibrillation-caused ischemic stroke

Background

We aimed to determine whether higher neutrophil counts (NC) and neutrophil-to-lymphocyte ratio (NLR) were independently predictive of worse in-hospital outcome in patients after acute ischemic stroke (IS).

Methods

A retrospective observational study with prospective manner of IS registration. Between April 2012 and August 2014, a total number of 1731 patients with post-IS were consecutively enrolled in the study. Blood samples were drawn upon admission. Primary endpoint was in-hospital mortality. Secondary endpoint was severe stroke (≥16 NIHSS).

Results

The NC progressively increased from mild (NIHSS ≤ 5) to moderate (NIHSS ≥ 6 < 16) and severe (NIHSS ≥ 16) stroke (p = 0.006). NLR was independently associated with in-hospital mortality (p = 0.002). Multiple stepwise linear regression analysis showed that NC (p = 0.001) and NLR (p = 0.002) were independently predictive of higher NIHSS. Multiple stepwise logistic regression analysis showed that NC was independently associated with severe stroke (p < 0.0001). The best discriminating factor for in-hospital mortality with respect to NLR was ≥3.20 (sensitivity 62.7%, specificity 60.3%, likelihood ratio: 12.2). Patients with NLR ≥3.20 had a 2.55-fold increased risk for in-hospital mortality (OR = 1.49–4.37) compared to patients with NLR <3.20. The best discriminating factor for severe stroke (≥16 NIHSS) with respect to NC was ≥74% (sensitivity 47.1%, specificity 74.0%, likelihood ratio: 29.0). Patients with NC >74% had a 2.54-fold increased risk of severe stroke (OR = 1.82–3.54) compared to patients with NC <74%.

Conclusion

NLR was independently associated with in-hospital mortality and higher NC was independently predictive of severe stroke.

Emerging Roles of microRNAs in Ischemic Stroke: As Possible Therapeutic Agents

Stroke is one of the leading causes of death and physical disability worldwide. The consequences of stroke injuries are profound and persistent, causing in considerable burden to both the individual patient and society. Current treatments for ischemic stroke injuries have proved inadequate, partly owing to an incomplete understanding of the cellular and molecular changes that occur following ischemic stroke. MicroRNAs (miRNA) are endogenously expressed RNA molecules that function to inhibit mRNA translation and have key roles in the pathophysiological processes contributing to ischemic stroke injuries. Potential therapeutic areas to compensate these pathogenic processes include promoting angiogenesis, neurogenesis and neuroprotection. Several miRNAs, and their target genes, are recognized to be involved in these recoveries and repair mechanisms. The capacity of miRNAs to simultaneously regulate several target genes underlies their unique importance in ischemic stroke therapeutics. In this Review, we focus on the role of miRNAs as potential diagnostic and prognostic biomarkers, as well as promising therapeutic agents in cerebral ischemic stroke.

Serum MicroRNAs Reflect Injury Severity in a Large Animal Model of Thoracic Spinal Cord Injury

Therapeutic development for spinal cord injury is hindered by the difficulty in conducting clinical trials, which to date have relied solely on functional outcome measures for patient enrollment, stratification, and evaluation. Biological biomarkers that accurately classify injury severity and predict neurologic outcome would represent a paradigm shift in the way spinal cord injury clinical trials could be conducted. MicroRNAs have emerged as attractive biomarker candidates due to their stability in biological fluids, their phylogenetic similarities, and their tissue specificity. Here we characterized a porcine model of spinal cord injury using a combined behavioural, histological, and molecular approach. We performed next-generation sequencing on microRNAs in serum samples collected before injury and then at 1, 3, and 5 days post injury. We identified 58, 21, 9, and 7 altered miRNA after severe, moderate, and mild spinal cord injury, and SHAM surgery, respectively. These data were combined with behavioural and histological analysis. Overall miRNA expression at 1 and 3 days post injury strongly correlates with outcome measures at 12 weeks post injury. The data presented here indicate that serum miRNAs are promising candidates as biomarkers for the evaluation of injury severity for spinal cord injury or other forms of traumatic, acute, neurologic injury.

Blood Occludin Level as a Potential Biomarker for Early Blood Brain Barrier Damage Following Ischemic Stroke

Concern about intracerebral hemorrhage (ICH) is the primary reason for withholding tPA therapy from patients with ischemic stroke. Early blood brain barrier (BBB) damage is the major risk factor for fatal post-thrombolysis ICH, but rapidly assessing BBB damage before tPA administration is highly challenging. We recently reported that ischemia induced rapid degradation of tight junction protein occludin in cerebromicrovessels. The present study investigates whether the cleaved occludin is released into the blood stream and how blood occludin levels correlate to the extent of BBB damage using a rat model of ischemic stroke. Cerebral ischemia induced a time-dependent increase of blood occludin with a sharp increase at 4.5-hour post-ischemia onset, which concurrently occurred with the loss of occludin from ischemic cerebral microvessels and a massive BBB leakage at 4.5-hour post-ischemia. Two major occludin fragments were identified in the blood during cerebral ischemia. Furthermore, blood occludin levels remained significantly higher than its basal level within the first 24 hours after ischemia onset. Our findings demonstrate that blood occludin levels correlate well with the extent of BBB damage and thus may serve as a clinically relevant biomarker for evaluating the risk of ICH before tPA administration.

MicroRNA-181c Exacerbates Brain Injury in Acute Ischemic Stroke

MicroRNA-181 (miR-181) is highly expressed in the brain, and downregulated in miRNA expression profiles of acute ischemic stroke patients. However, the roles of miR-181c in stroke are not known. The clinical relevance of miR-181c in acute stroke patients was evaluated by real-time PCR and correlation analyses. Proliferation and apoptosis of BV2 microglial cells and Neuro-2a cells cultured separately or together under oxidative stress or inflammation were assessed with the Cell Counting Kit-8 and by flow cytometry, respectively. Cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in C57/BL6 mice, and cerebral infarct volume, microglia activation, and expression of pro-apoptotic factors were evaluated by 2,3,5-triphenyl-2H-tetrazolium chloride staining, immunocytochemistry, and western blotting, respectively. Plasma levels of miR-181c were decreased in stroke patients relative to healthy individuals, and were positively correlated with neutrophil number and blood platelet count and negatively correlated with lymphocyte number. Lipopolysaccharide (LPS)/hydrogen peroxide (H₂O₂) treatment inhibited BV2 microglia proliferation without inducing apoptosis, while miR-181c reduced proliferation but increased the apoptosis of these cells with or without LPS/H₂O₂ treatment. LPS/H₂O₂ induced apoptosis in Neuro-2a cells co-cultured with BV2 cells, an effect that was potentiated by miR-181c. In the MCAO model, miR-181c agomir modestly increased infarct volume, markedly decreased microglia activation and B cell lymphoma-2 expression, and increased the levels of pro-apoptotic proteins in the ischemic brain. Our data indicate that miR-181c contributes to brain injury in acute ischemic stroke by promoting apoptosis of microglia and neurons via modulation of pro- and anti-apoptotic proteins.

Machine-learning approach identifies a pattern of gene expression in peripheral blood that can accurately detect ischaemic stroke

Early and accurate diagnosis of stroke improves the probability of positive outcome. The objective of this study was to identify a pattern of gene expression in peripheral blood that could potentially be optimised to expedite the diagnosis of acute ischaemic stroke (AIS). A discovery cohort was recruited consisting of 39 AIS patients and 24 neurologically asymptomatic controls. Peripheral blood was sampled at emergency department admission, and genome-wide expression profiling was performed via microarray. A machine-learning technique known as genetic algorithm k-nearest neighbours (GA/kNN) was then used to identify a pattern of gene expression that could optimally discriminate between groups. This pattern of expression was then assessed via qRT-PCR in an independent validation cohort, where it was evaluated for its ability to discriminate between an additional 39 AIS patients and 30 neurologically asymptomatic controls, as well as 20 acute stroke mimics. GA/kNN identified 10 genes (ANTXR2, STK3, PDK4, CD163, MAL, GRAP, ID3, CTSZ, KIF1B and PLXDC2) whose coordinate pattern of expression was able to identify 98.4% of discovery cohort subjects correctly (97.4% sensitive, 100% specific). In the validation cohort, the expression levels of the same 10 genes were able to identify 95.6% of subjects correctly when comparing AIS patients to asymptomatic controls (92.3% sensitive, 100% specific), and 94.9% of subjects correctly when comparing AIS patients with stroke mimics (97.4% sensitive, 90.0% specific). The transcriptional pattern identified in this study shows strong diagnostic potential, and warrants further evaluation to determine its true clinical efficacy.

Upregulation of CD74 and its potential association with disease severity in subjects with ischemic stroke

Macrophage migration inhibitory factor (MIF) is a key cytokine/chemokine in the activation and recruitment of inflammatory T lymphocytes known to exacerbate experimental stroke severity. MIF effects are mediated through its primary cellular receptor, CD74, the MHC class II invariant chain present on all class II expressing cells, including monocytes, macrophages and dendritic cells (DC). We demonstrated previously that partial MHC class II/peptide constructs (pMHC) can effectively treat mice with experimental stroke, in part through their ability to competitively inhibit MIF/CD74 interactions and downstream signaling. However, the role of MIF and CD74 in human ischemic stroke is not yet well established. To evaluate the therapeutic potential for pMHC, we assessed MIF and CD74 expression levels and their association with disease outcome in subjects with ischemic stroke. MIF levels were assessed in blood plasma by ELISA and CD74 expression was quantified by flow cytometry and qRT-PCR in peripheral blood mononuclear cells (PBMCs) obtained from subjects with ischemic stroke and age and sex-matched healthy controls (HC). MIF levels were increased in plasma and the number of CD74⁺ cells and CD74 mRNA expression levels were significantly increased in PBMC of subjects with ischemic stroke versus HC, mainly on CD4⁺ T cells, monocytes and DC. Greater increases of CD74⁺ cells were seen in subjects with cortical vs. subcortical infarcts and the number of CD74⁺ cells in blood correlated strongly with infarct size and neurological outcomes. However, differences in MIF and CD74 expression were not affected by age, gender or lesion laterality. Increased CD74 expression levels may serve as a useful biomarker for worse stroke severity and predicted outcomes in subjects with ischemic stroke and provide a rationale for potential future treatment with pMHC constructs.

Characterizing Dysregulated Networks in Individual Patients with Ischemic Stroke Based on Monte Carlo Cross-Validation

The purpose of this study was to introduce a new method to elucidating the molecular mechanisms in ischemic stroke. Genes from microarray data were performed enrichment to biological pathways. Dysregulated pathways and dysregulated pathway pairs were identified and constructed into networks. After Random Forest classification was performed, area under the curve (AUC) value of main network was calculated. After 50 bootstraps of Monte Carlo Cross-Validation, six pairs of pathways were found for >40 times. The best main network with AUC value = 0.735 was identified, including 14 pairs of pathways. Compared with the traditional method (gene set enrichment analysis), although a small part of pathways were shared, most of the pathways were closely related with ischemic stroke. The best network may give new insights into the underlying molecular mechanisms in ischemic stroke. It may play pivotal roles in the progression of ischemic stroke and particular attention should be focused on them for further research.

Increased Expression of mir-34a-5p and Clinical Association in Acute Ischemic Stroke Patients and in a Rat Model

BACKGROUND MiRNA is widely recognized as the most important regulator in various diseases. However, there has been little research regarding miRNA expression and its involvement in ischemic stroke. MATERIAL AND METHODS In this study, we investigated the pattern of miRNA-34a-5p expression along with its clinical application in human ischemic stroke and in an in vivo rat model. We recruited 102 cerebral ischemia patients and 97 health controls for this study. Clinical data were gathered and recorded with the help of questionnaires. Blood samples were obtained from patients within 72 h after cerebral ischemia. National Institutes of Health Stroke Scale (NIHSS), Acute Stroke Treatment (TOAST), and infarct volume were used to analyze the correlation of miRNA-34a-5p expression and clinical information. In addition, blood samples and brain tissues were collected from an established middle cerebral artery occlusion (MCAO) model consisting of 20 adult male mice at 24 h after the MCAO. Expression level of miRNA-34a-5p was detected by real-time polymerase chain reactions. RESULTS Results showed overexpression of miRNA-34a-5p in acute ischemic stroke patients blood samples compared to the controls (p<0.05). Also, large and small arterial strokes types demonstrated elevated miRNA-34a-5p expression levels. Further correlation analysis revealed a negative association between miRNA-34a-5p and NIHSS scores (r=-0.692 p<0.05) and infarct volume (r=-0.719, p<0.05). Moreover, in vivo experiment results showed significant up-regulated expression of miRNA-34a-5p in middle cerebral artery occlusion compared to controls, along with a positive correlation between miRNA-34a-5p in blood and brain (r=0.742, p<0.05). CONCLUSIONS Our results suggest there is a potential regulatory role of miRNA-34a-5p in acute ischemic stroke, which could serve as a therapeutic target or biomarker in stroke prognosis.

The prognostic value of biomarkers in stroke

Background

Ischemic injury triggers inflammatory cascades and changes in the protein synthesis, neurotransmitters and neuro-hormones in the brain parenchyma that may further amplify the tissue damage. The “Triage® Stroke Panel”, a biochemical multimarker assay, detects Brain Natriuretic Peptide (BNP), D-Dimers (DD), Matrix-Metalloproteinase-9 (MMP-9), and S100β protein generating a Multimarker index of these values (MMX). The aims of this prospective study in consecutive patients with ischemic or hemorrhagic stroke were to assess: 1) the rate of an increase of biomarkers (BNP, D-dimer, MMP-9 and S-100β) tested with the Triage Stroke Panel; 2) the correlation between the increase of these biomarkers and functional outcome at 4 months; 3) the risk factors for the increase of biomarkers.

Methods

The outcome of the study was 120-day mortality and it was compared in patients with Stroke Panel >4 and ≤4. Multiple logistic regression analyses were performed to identify independent predictors for death and for the increase of biomarkers.

Results

244 consecutive patients (mean age 73.02 years; 53.7 % males) were included in the study; 210 ischemic strokes and 34 hemorrhagic strokes. 161/244 (66.0 %) had an increase of biomarkers. At 120 days, 85 patients had died (34.8 %). Death was seen in 68/161 patients with an increase of biomarkers (42.2 %) compared with 17/83 patients without (20.5 %). Regression logistic analysis found that a Stroke Panel >4 (OR 3.1; 95 % CI 1.5–6.2, p = 0.002) was associated with mortality. The increase of biomarkers was independently predicted by an increase of PCR on admission (OR 2.9, 95 CI 1.4–6.0, p = 0.003).

Conclusions

An increase of biochemical markers such as BNP, D-Dimers, MMP-9, and S100β tested with a Triage Stroke Panel (>4) was correlated with mortality at 120 days from stroke onset.

Lipocalin-2 as an Infection-Related Biomarker to Predict Clinical Outcome in Ischemic Stroke

OBJECTIVES

From previous data in animal models of cerebral ischemia, lipocalin-2 (LCN2), a protein related to neutrophil function and cellular iron homeostasis, is supposed to have a value as a biomarker in ischemic stroke patients. Therefore, we examined LCN2 expression in the ischemic brain in an animal model and measured plasma levels of LCN2 in ischemic stroke patients.

METHODS

In the mouse model of transient middle cerebral artery occlusion (tMCAO), LCN2 expression in the brain was analyzed by immunohistochemistry and correlated to cellular nonheme iron deposition up to 42 days after tMCAO. In human stroke patients, plasma levels of LCN2 were determined one week after ischemic stroke. In addition to established predictive parameters such as age, National Institutes of Health Stroke Scale and thrombolytic therapy, LCN2 was included into linear logistic regression modeling to predict clinical outcome at 90 days after stroke.

RESULTS

Immunohistochemistry revealed expression of LCN2 in the mouse brain already at one day following tMCAO, and the amount of LCN2 subsequently increased with a maximum at 2 weeks after tMCAO. Accumulation of cellular nonheme iron was detectable one week post tMCAO and continued to increase. In ischemic stroke patients, higher plasma levels of LCN2 were associated with a worse clinical outcome at 90 days and with the occurrence of post-stroke infections.

CONCLUSIONS

LCN2 is expressed in the ischemic brain after temporary experimental ischemia and paralleled by the accumulation of cellular nonheme iron. Plasma levels of LCN2 measured in patients one week after ischemic stroke contribute to the prediction of clinical outcome at 90 days and reflect the systemic response to post-stroke infections.

Apolipoprotein A1-Unique Peptide as a Diagnostic Biomarker for Acute Ischemic Stroke

Clinically-informative biomarkers of ischemic stroke are needed for rapid diagnosis and timely treatment. In the present study, APOA1 unique peptide (APOA1-UP), a novel peptide biomarker, was identified and quantified by multiple reaction monitoring (MRM) using labeled reference peptide (LRP). Serum samples of 94 patients in the ischemic stroke group and 37 patients in the non-stroke group were analyzed for the levels of total APOA1-UP, low density lipoprotein cholesterol (LDL-C), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and total cholesterol (TC). Median ratio of total APOA1-UP/LRP was 2.14 (interquartile range, 0.40) in the non-stroke group and 1.32 (0.44) in the ischemic stroke group (p < 0.0001). The serum level of total APOA1-UP was independently correlated with the presence of ischemic stroke by multivariate logistic regression analysis (p < 0.0001). From the receiver operating characteristic (ROC) curve, the area under the curve (AUC) was 0.9750 and the optimal cutoff value of the serum APOA1-UP level was 1.80, which yielded a sensitivity of 90.63% and a specificity of 97.14%. The diagnostic efficiency of HDL-C was lower, with an AUC of 0.7488. Therefore, the serum level of APOA1-UP is a diagnostic biomarker candidate for ischemic stroke in the early stage.

Remote ischemic preconditioning in the prevention of ischemic brain damage during intracranial aneurysm treatment (RIPAT): study protocol for a randomized controlled trial

BACKGROUND

The treatment of intracranial aneurysms may be associated with cerebral ischemia. We hypothesize that pre-interventional remote ischemic preconditioning (RIPC) reduces ischemic cerebral tissue damage in patients undergoing elective intracranial aneurysm treatment.

METHODS/DESIGN

This study is a single-center, prospective, randomized, double-blind explorative trial. Patients with an unruptured intracranial aneurysm admitted to Innsbruck Medical University Hospital for coiling or clipping will be consecutively randomized to either the intervention group (= RIPC by inflating an upper extremity blood-pressure cuff for 3 x 5 min to 200 mmHg) or the control group after induction of anesthesia. Participants will be randomized 1:1 to either the preconditioning group or the sham group using a random allocation sequence and block randomization. The precalculated sample size is n = 24 per group. The primary endpoint is the area-under-the-curve concentration of serum biomarkers (S100B, NSE, GFAP, MMP9, MBP, and cellular microparticles) in the first five days after treatment. Secondary endpoints are the number and volume of new ischemic lesions in magnetic resonance imaging and clinical outcome evaluated with the National Institutes of Health Stroke Scale, the modified Rankin Scale, and neuropsychological tests at six and twelve months. All outcome variables will be determined by observers blinded to group allocation. This study was approved by the local institutional Ethics Committee (UN5164), version 3.0 of the study protocol, dated 20 October 2013.

DISCUSSION

This study uses the elective treatment of intracranial aneurysms as a paradigmatic situation to explore the neuroprotective effects of RIPC. If effects are demonstrable in this pilot trial, a larger, prospective phase III trial will be considered.