Ischemic stroke biomarkers in blood

Quantitative analysis of selected genetic markers of induced brain stroke ischemic tolerance detected in human blood

A brain stroke is a serious disease and the second leading cause of death in the European Union. Carotid stenosis accounts for 15% of all ischemic cerebral strokes. However, there is currently no effective screening for carotid disease. Analysis of the DNA from peripheral blood is increasingly being used for several disease diagnoses. The potentially beneficial therapeutic method of inducing tissue tolerance to ischemia has so far been studied mainly in animal models. The aim of this study is to investigate changes in the gene expression of selected markers of brain ischemia during carotid endarterectomy, considered in this study as an activator of ischemic tolerance. During the carotid endarterectomy, there is a short-term occlusion of the internal carotid artery. Using the RT-qPCR method, we detected changes in the early identified gene markers of brain ischemia (ADM, CDKN1A, GADD45G, IL6, TM4SF1) in peripheral blood during sub lethal cerebral ischemia caused by carotid endarterectomy. Patients underwenting surgical procedure were divided into three groups: asymptomatic, symptomatic, and those who underwent carotid endarterectomy after an acute stroke. The results were compared to a negative/control group. Carotid endarterectomy had an impact on the expression of all monitored biomarkers. We observed statistically significant changes (p value 0.05-0.001) when comparing the groups among themselves, as well as the presence of ischemic tolerance of brain tissue to ischemic attacks. In conclusion, ADM, GADD45G, and TM4SF1 were affected in symptomatic patients, GADD45G and IL6 in acute patients, and CDKN1A and ADM in asymptomatic group after application of carotid endarterectomy.

The role of circulating cell-free DNA as an inflammatory mediator after stroke

Stroke is the second leading cause of death worldwide and a leading cause of disability. Clinical and experimental studies highlighted the complex role of the immune system in the pathophysiology of stroke. Ischemic brain injury leads to the release of cell-free DNA, a damage-associated molecular pattern, which binds to pattern recognition receptors on immune cells such as toll-like receptors and cytosolic inflammasome sensors. The downstream signaling cascade then induces a rapid inflammatory response. In this review, we are highlighting the characteristics of cell-free DNA and how these can affect a local as well as a systemic response after stroke. For this purpose, we screened literature on clinical studies investigating cell-free DNA concentration and properties after brain ischemia. We report the current understanding for mechanisms of DNA uptake and sensing in the context of post-stroke inflammation. Moreover, we compare possible treatment options targeting cell-free DNA, DNA-sensing pathways, and the downstream mediators. Finally, we describe clinical implications of this inflammatory pathway for stroke patients, open questions, and potential future research directions.

Therapeutic Efficacy of Boric Acid Treatment on Brain Tissue and Cognitive Functions in Rats with Experimental Alzheimer's Disease

INTRODUCTION

Oxidative stress has an important role in the pathophysiology of Alzheimer's disease (AD), the most common type of dementia. Boric acid (BA) contributes significantly to the protection of the brain by reducing lipid peroxidation and supporting antioxidant defense. We aimed to evaluate the therapeutic potential of BA treatment in AD rats.

MATERIALS AND METHODS

Four groups were formed as Control (C), Alzheimer's (A), Alzheimer's + Boric acid (ABA), Boric acid (BA). Intracerebroventricular injection of Streptozotocin (STZ) was preferred to create an AD. After 4 weeks, BA was applied 3 times every other day. The Radial Arm Maze Test (RAMT) was used to evaluate memory and learning abilities. Biochemical and histopathological evaluations were made in the hippocampus.

RESULTS

Initial RAMT inlet/outlet (I/O) numbers were similar. Two weeks after STZ injection, I/O numbers decreased in group A and ABA compared to group C and BA (p<0.05). After the second BA application, I/O numbers increased in the ABA group compared to the A group (p<0.05). In group A, PON-1, TOS and OSI levels were higher and TAS levels were lower than in groups BA and C. After BA treatment, PON-1 and OSI levels were lower in the ABA group than in the A group (p<0.05). Although there was an increase in TAS value and a decrease in TOS, this did not make a statistical difference. The thickness of the pyramidal cell in CA1 and the granular cell layers in the dentate gyrus, and the number of intact and degenerated neurons in the pyramidal cell layer were similar between the groups.

DISCUSSION

Significant improvement in learning and memory abilities after BA application is promising for AD.

CONCLUSION

These results show that BA application positively affects learning and memory abilities, and reduces oxidative stress. More extensive studies are required to evaluate histopathological efficacy.

Multiplex analysis of cytokines in the cerebrospinal fluid of dogs after ischemic stroke reveals elevations in chemokines CXCL1 and MCP-1

Introduction

Neuroinflammation that occurs in the brain after stroke has been shown to be important to disease pathogenesis and outcomes. The aim of this study was to evaluate a large number of pro- and anti-inflammatory cytokines in dogs with clinically-confirmed, naturally occurring stroke.

Materials and methods

Fifteen dogs with a clinical diagnosis of ischemic stroke and ten healthy control dogs were included in the study. A multiplex immunoassay was utilized to evaluate cerebrospinal fluid for GM-CSF, IFN-γ, IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-15, IL-18, IP-10, CXCL1, MCP-1, and TNF-α.

Results

Mean concentrations of CXCL1 (stroke-436 pg/ml, control-267 pg/ml, p = 0.01) and MCP-1 (stroke-196 pg/ml, control-66 pg/ml, p ≤ 0.0001) were significantly elevated in dogs with stroke when compared with control dogs. Location and type of infarct, duration of clinical signs, and use of anti-inflammatory medications were not associated with differences in cytokine concentration.

Discussion

CXCL1 and MCP-1 may play a role in naturally occurring canine stroke and represent targets for future research.

NR-2 antikor peptid düzeyinin akut iskemik inmede tanı, prognoz ve koma skorları ile ilişkisi var mıdır?

Aim: This study aimed to demonstrate the diagnostic and prognostic value of NR-2 peptides as a biomarker in acute ischemic stroke and to evaluate their correlation with the Glasgow Coma Scale (GCS) and the National Institutes of Health Stroke Scale (NIHSS). Materials and Methods: This is a prospective study evaluating the value of NR-2 peptide levels in the diagnosis and prognosis of acute stroke. The study included 101 patients, who presented to a tertiary healthcare facility and were diagnosed with acute stroke, and 57 healthy controls. In the whole study population, serum NR-2 peptide levels were measured using the ELISA method. Results: The NR-2 peptide level was 6.32 ± 8.30 in the patient group and 3.91 ± 1.64 in the study group. The NR-2 peptide level was significantly higher in the patient group (p = 0.006). No correlation was detected between NR-2 peptide levels and scores in the GCS or NIHSS. The results indicated that NR-2 was a potential biomarker elevated in the early phase of acute stroke, but had no correlation with the prognosis of acute stroke. Conclusion: Although our data shed light on the use of the NR-2 peptide level as a biomarker in the acute phase in patients with stroke, data are insufficient to predict prognosis. We think that larger, multicentre studies with longer follow-up periods are needed.

A review of surface-enhanced Raman spectroscopy in pathological processes

With the continuous growth of the human population and new challenges in the quality of life, it is more important than ever to diagnose diseases and pathologies with high accuracy, sensitivity and in different scenarios from medical implants to the operation room. Although conventional methods of diagnosis revolutionized healthcare, alternative analytical methods are making their way out of academic labs into clinics. In this regard, surface-enhanced Raman spectroscopy (SERS) developed immensely with its capability to achieve single-molecule sensitivity and high-specificity in the last two decades, and now it is well on its way to join the arsenal of physicians. This review discusses how SERS is becoming an essential tool for the clinical investigation of pathologies including inflammation, infections, necrosis/apoptosis, hypoxia, and tumors. We critically discuss the strategies reported so far in nanoparticle assembly, functionalization, non-metallic substrates, colloidal solutions and how these techniques improve SERS characteristics during pathology diagnoses like sensitivity, selectivity, and detection limit. Moreover, it is crucial to introduce the most recent developments and future perspectives of SERS as a biomedical analytical method. We finally discuss the challenges that remain as bottlenecks for a routine SERS implementation in the medical room from in vitro to in vivo applications. The review showcases the adaptability and versatility of SERS to resolve pathological processes by covering various experimental and analytical methods and the specific spectral features and analysis results achieved by these methods.

Modifications of gene expression detected in peripheral blood after brain ischemia treated with remote postconditioning

BACKGROUND

A stroke is an acute damage to a certain area of a nerve tissue of the brain. In developed countries, it ranks second among the most often causes of death and is also the leading cause of disability. Recent findings emphasize the significant neuroprotective effect of conditioning on the course and rate of recovery after ischemic attack; however the molecular mechanism of ischemic tolerance induced by conditioning is still not completely explored.

METHODS AND RESULTS

The purpose of this study is an identification of changes in gene expression induced by stimulation of reaction cascades after activation of the neuroprotective mechanism using an experimental rat model of global ischemia. The induction of neuroprotective cascades was stimulated by the application of early and delayed form of remote ischemic postconditioning. The quantitative qRT-PCR method was used to assess the rate of change in ADM, BDNF, CDKN1A, CREB, GADD45G, IL6, nNOS, and TM4SF1 gene expression levels 72 h after ischemic attack. The detected results confirm the neuroprotective effect of both forms of postconditioning. Participation of neuroprotection-related gene expression changes was observed once as an early one (CREB, GADD45G), once as a delayed one (ADM, IL6), or both (BDNF, CDKN1A, nNOS, TM4SF1) postconditioning forms, depending on the particular gene.

CONCLUSIONS

Our results characterize impact of ischemic tolerance on the molecular level. We predict ischemic tolerance to be consisted of complex combination of early and delayed remote postconditioning.

Prospects of Therapeutic Target and Directions for Ischemic Stroke

Stroke is a serious, adverse neurological event and the third leading cause of death and disability worldwide. Most strokes are caused by a block in cerebral blood flow, resulting in neurological deficits through the death of brain tissue. Recombinant tissue plasminogen activator (rt-PA) is currently the only immediate treatment medication for stroke. The goal of rt-PA administration is to reduce the thrombus and/or embolism via thrombolysis; however, the administration of rt-PA must occur within a very short therapeutic timeframe (3 h to 6 h) after symptom onset. Components of the pathological mechanisms involved in ischemic stroke can be used as potential biomarkers in current treatment. However, none are currently under investigation in clinical trials; thus, further studies investigating biomarkers are needed. After ischemic stroke, microglial cells can be activated and release inflammatory cytokines. These cytokines lead to severe neurotoxicity via the overactivation of microglia in prolonged and lasting insults such as stroke. Thus, the balanced regulation of microglial activation may be necessary for therapy. Stem cell therapy is a promising clinical treatment strategy for ischemic stroke. Stem cells can increase the functional recovery of damaged tissue after post-ischemic stroke through various mechanisms including the secretion of neurotrophic factors, immunomodulation, the stimulation of endogenous neurogenesis, and neovascularization. To investigate the use of stem cell therapy for neurological diseases in preclinical studies, however, it is important to develop imaging technologies that are able to evaluate disease progression and to “chase” (i.e., track or monitor) transplanted stem cells in recipients. Imaging technology development is rapidly advancing, and more sensitive techniques, such as the invasive and non-invasive multimodal techniques, are under development. Here, we summarize the potential risk factors and biomarker treatment strategies, stem cell-based therapy and emerging multimodal imaging techniques in the context of stroke. This current review provides a conceptual framework for considering the therapeutic targets and directions for the treatment of brain dysfunctions, with a particular focus on ischemic stroke.

Integration of ultra-high-pressure liquid chromatography-tandem mass spectrometry with machine learning for identifying fatty acid metabolite biomarkers of ischemic stroke

We report for the first time the integration of ultra-high-pressure liquid chromatography-tandem mass spectrometry with machine learning for identifying fatty acid metabolite biomarkers of ischemic stroke. In particular, we develop an optimal model to discriminate ischemic stroke patients from healthy persons with 100% sensitivity and 93.18% specificity. This research may facilitate understanding the roles of fatty acid metabolites in stroke occurrence, holding great potential in clinical stroke diagnosis.

Inflammatory Markers in Severity of Intracerebral Hemorrhage II: A Follow Up Study

Introduction

Spontaneous intracerebral hemorrhage (ICH) results in significant morbidity and mortality. The pathogenesis of brain injury after ICH is thought to be due to mechanical damage followed by ischemic, cytotoxic, and inflammatory changes in the underlying and surrounding tissue. Various inflammatory and non-inflammatory biomarkers have been studied as predictors and potential therapeutic targets for intracerebral hemorrhage. Our prior study showed an association with low vascular endothelial growth factor (VEGF) levels and increased mortality. This current study looks to expand on our prior results and will look at the relationship between tumor necrosis factor alpha (TNFα), C-reactive protein (CRP), VEGF, Homocysteine (Hcy), and CRP to albumin ratio (CAR) in predicting outcomes and severity in spontaneous intracerebral hemorrhage.

Methods

We conducted a retrospective chart review of patients with spontaneous intracerebral hemorrhage with TNFα, CRP, VEGF, Hcy levels drawn on admission. Albumin and CRP levels on admission were used to calculate CAR. Ninety-nine patients were included in the study. Primary outcomes included death, early neurologic decline (END), and hemorrhage size. Secondary outcomes included late neurologic decline (LND), Glasgow Coma Scale (GCS) on admission, GCS on discharge, ICH score, change in hemorrhage size, need for surgical intervention, and length of ICU stay.

Results

A total of 99 patients were included in this study, with 42% requiring surgical intervention and an overall mortality of 16%. Basal ganglia hemorrhage was seen in 41% of patients. Hcy and CAR were significantly correlated with ICH size in basal ganglia patients (r-=0.36, p=0.03; r=0.43, p=0.03, respectively). CAR was significantly correlated with ICH score (r=0.33, p=0.007874). Admission VEGF levels less than 45 pg/ml had 8.4-fold increase in mortality (odds ratio [OR] 8.4545, p=0.0488). Patients with TNFα levels greater than 1.40 pg/ml had a 4.1-fold increase in mortality (OR 4.1, p=0.04)

Conclusion

Our study demonstrated that low levels (<45 pg/ml) of VEGF were associated with an 8.4-fold increase in mortality, supporting the neuroprotective effect of this protein. Elevated Hcy and CAR levels were associated with an increase in hemorrhage size in patients with basal ganglia hemorrhages. TNFα levels greater than 1.40 pg/ml were associated with a 4.1-fold increase in mortality, and this together with CAR being correlated with increased hemorrhage size and ICH score further demonstrate the inflammatory consequences after intracerebral hemorrhage. Future studies directed at lowering CRP, TNFα, and Hcy and/or increasing VEGF in intracerebral hemorrhage patients are needed and may be beneficial.

A Mouse Brain-based Multi-omics Integrative Approach Reveals Potential Blood Biomarkers for Ischemic Stroke

Stroke remains a leading cause of death and disability worldwide. Despite continuous advances, the identification of key molecular signatures in the hyper-acute phase of ischemic stroke is still a primary interest for translational research on stroke diagnosis, prognosis, and treatment. Data integration from high-throughput -omics techniques has become crucial to unraveling key interactions among different molecular elements in complex biological contexts, such as ischemic stroke. Thus, we used advanced data integration methods for a multi-level joint analysis of transcriptomics and proteomics data sets obtained from mouse brains at 2 h after cerebral ischemia. By modeling net-like correlation structures, we identified an integrated network of genes and proteins that are differentially expressed at a very early stage after stroke. We validated 10 of these deregulated elements in acute stroke, and changes in their expression pattern over time after cerebral ischemia were described. Of these, CLDN20, GADD45G, RGS2, BAG5, and CTNND2 were next evaluated as blood biomarkers of cerebral ischemia in mice and human blood samples, which were obtained from stroke patients and patients presenting stroke-mimicking conditions. Our findings indicate that CTNND2 levels in blood might potentially be useful for distinguishing ischemic strokes from stroke-mimicking conditions in the hyper-acute phase of the disease. Furthermore, circulating GADD45G content within the first 6 h after stroke could also play a key role in predicting poor outcomes in stroke patients. For the first time, we have used an integrative biostatistical approach to elucidate key molecules in the initial stages of stroke pathophysiology and highlight new notable molecules that might be further considered as blood biomarkers of ischemic stroke.

Cell-free nucleic acid patterns in disease prediction and monitoring-hype or hope?

Interest in the use of cell-free nucleic acids (CFNAs) as clinical non-invasive biomarker panels for prediction and prevention of multiple diseases has greatly increased over the last decade. Indeed, circulating CFNAs are attributable to many physiological and pathological processes such as imbalanced stress conditions, physical activities, extensive apoptosis of different origin, systemic hypoxic-ischemic events and tumour progression, amongst others. This article highlights the involvement of circulating CFNAs in local and systemic processes dealing with the question, whether specific patterns of CFNAs in blood, their detection, quantity and quality (such as their methylation status) might be instrumental to predict a disease development/progression and could be further utilised for accompanying diagnostics, targeted prevention, creation of individualised therapy algorithms, therapy monitoring and prognosis. Presented considerations conform with principles of 3P medicine and serve for improving individual outcomes and cost efficacy of medical services provided to the population.

Vascular injury biomarkers and stroke risk

Objective

Because little is known about associations between biomarkers of vascular injury and stroke risk, we evaluated associations between plasma concentrations of 6 novel biomarkers of vascular injury and stroke risk in a population-based study.

Methods

A case–cohort subset of EPIC-Heidelberg (European Prospective Investigation for Cancer and Nutrition–Heidelberg) including incident stroke cases (n = 335) and a random subcohort (n = 2,418) was selected. Concentrations of intercellular adhesion molecule 3 (ICAM3), soluble E-selectin and P-selectin, soluble thrombomodulin (sTM), thrombopoietin, and glycoprotein IIb/IIIa were measured in baseline plasma samples. Weighted Cox regression analyses were used to assess associations between biomarker levels and stroke risk.

Results

Median follow-up in the subcohort and among cases was 9.8 (range, 0.1–12.5) years and 6.2 (range, 0.01–12.1) years, respectively. ICAM3 levels were associated with increased risk of incident stroke after multivariable adjustment (hazard ratio, highest vs lowest quartile: 1.64 [95% confidence interval, 1.15–2.32]; plinear trend < 0.001). This association was more apparent for ischemic (1.65 [1.12–2.45]; plinear trend < 0.01) than for hemorrhagic stroke (1.29 [0.60–2.78]; plinear trend = 0.3). We further observed a borderline significant trend for a positive association between sTM and overall stroke risk (1.47 [0.99–2.19]; plinear trend = 0.05).

Conclusions

In this population-based study, circulating levels of ICAM3, an adhesion molecule shed by leukocytes, were associated with increased risk of incident stroke. Further mechanistic studies are needed to elucidate the pathophysiology underlying this association.

Classification of evidence

This study provides Class II evidence that plasma levels of ICAM3 are associated with increased stroke risk.

Prognostic Value of NT-proBNP After Ischemic Stroke: A Systematic Review and Meta-analysis of Prospective Cohort Studies

BACKGROUND

Many studies have evaluated the relationship between N-terminal pro-brain natriuretic peptide (NT-proBNP) and its prognostic value in ischemic stroke. However, a widespread consensus has not been reached. Therefore, we completed a meta-analysis to evaluate the prognostic significance of NT-proBNP for mortality and functional outcome in patients with ischemic stroke.

METHODS

We performed a systematic search and review using the PubMed and EMBASE databases to identify literature that reported a correlation between NT-proBNP and mortality and functional outcome in ischemic stroke patients.

RESULTS

Eleven studies inclusive of 10,498 patients met the inclusion criteria. Elevated plasma NT-proBNP levels were associated with increased risk of mortality in ischemic stroke patients (all-cause mortality: odds ratio [OR] = 2.43, 95% confidence interval [CI] 1.62-3.64, P < .001, I²=74.3%; cardiovascular mortality: OR = 2.01, 95% CI 1.55-2.61, P < .001, I² = 42.6%). In addition, unfavorable functional outcomes were observed in patients with higher levels of NT-proBNP (OR = 1.68, 95% CI 1.13-2.50, P = .01, I² = 90.8%) after ischemic stroke.

CONCLUSIONS

This meta-analysis demonstrates that NT-proBNP could be a predictor of mortality and functional outcome in ischemic stroke patients.

Blood transcriptomic biomarker as a surrogate of ischemic brain gene expression

Objectives

Blood biomarkers for cerebral tissue ischemia are lacking. The goal was to identify a blood transcriptomic signature jointly identified in the ischemic brain.

Methods

A nonhuman primate model with middle cerebral artery (MCA) territory infarction was used to study gene expression by microarray during acute ischemic cerebral stroke in the brain and the blood. Brain samples were collected in the infarcted and contralateral non‐infarcted cortex as well as blood samples before and after occlusion. Gene expression was compared between the two brain locations to find differentially expressed genes. The expressions of these genes were then compared in the blood pre‐ and post‐occlusion.

Results

Hierarchical clustering of brain expression data revealed strong independent clustering of ischemic and nonischemic brain samples. The top five enriched, up‐regulated gene sets in the brain were TNF α signaling, apoptosis, P53 pathway, hypoxia, and UV response up. A comparison of differentially expressed genes in the brain and blood revealed a significant overlap of gene expression patterns. Stringent analysis of blood expression data from pre‐ and post‐occlusion samples in each monkey identified nine genes highly differentially expressed in both the brain and the blood. Many of these up‐regulated genes belong to pathways involved in cell death and DNA damage repair.

Interpretation

Common gene expression profile can be identified in the brain and blood and clearly differentiates ischemic from nonischemic conditions. Therefore, specific blood transcriptomic signature may represent a surrogate for brain ischemic gene expression.

Comparison of plasma PARK7 and NDKA diagnostic value in acute stroke

AIM

In this prospective case-control study we aimed to compare diagnostic value of plasma PARK7 and NDKA in early diagnosis of acute stroke and evaluate the validated diagnostic values of PARK7 and NDKA in an independent patient cohort. We then assessed the quantitative relationship between the release of these markers: stroke severity and time. Blood samples were drawn upon hospital admission and 14 days later. PARK7 and NDKA concentrations were measured using an ELISA.

RESULTS

The expression of PARK7 (area under the curve [AUC] = 0.897) in acute stroke patients was more significant than in controls, relative to the NDKA expression (AUC = 0.462); p < 0.05. Their expressions were not related to the clinical characteristics of both groups; p > 0.05.

CONCLUSION

Even though both markers cannot differentiate stroke etiologies (ischemic or hemorrhagic), plasma PARK7 has better diagnostic value than NDKA for early diagnosis of stroke. 72 plasma samples obtained from acute stroke patients and 78 plasma samples collected from non-stroke patients were analyzed in this study.

Cross-Reactivity as a Mechanism Linking Infections to Stroke

The relevance of infections as risk factor for cerebrovascular disease is being increasingly recognized. Nonetheless, the pathogenic link between the two entities remains poorly understood. Consistent with recent advances in medicine, the present work addresses the hypothesis that infection-induced immune responses may affect human proteins associated with stroke. Applying established procedures in bioinformatics, the pathogen antigens and the human proteins were searched for common sequences using pentapeptides as probes. The resulting data demonstrate massive peptide sharing between infectious pathogens-such as Chlamydia pneumoniae, Streptococcus pneumoniae, Tannerella forsythia, Haemophilus influenzae, Influenza A virus, and Cytomegalovirus-and human proteins related to risk of ischemic and hemorrhagic stroke. Moreover, the shared peptides are also evident in a number of epitopes experimentally proven immunopositive in the human host. The present findings suggest cross-reactivity as a potential mechanistic link between infections and stroke.

Dynamic changes in miR-124 levels in patients with acute cerebral infarction

OBJECTIVE

To investigate the changes in serum miR-124 levels in patients with acute cerebral infarction (ACI) and elucidate the underlying mechanism by a dynamic monitor.

METHODS

Fifty-four patients with ACI and 51 healthy controls were included in our study. Baseline characteristics and blood samples were collected for further analysis. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure the serum miR-124 levels. The dual-luciferase reporter assay was used to evaluate the effect of miR-124 on iASPP, a protein that inhibits apoptosis stimulating proteins in the p53 family.

RESULTS

Compared with normal controls, the miR-124 levels in the ACI group rapidly decreased at phase 1 (within 24 h after ischemia) (p < 0.001) and then gradually increased at phase 2 (48 ∼ 72 h after ischemia) (p < 0.001) and phase 3 (the 7th day after ischemia) (p < 0.001). The dual-luciferase reporter assay showed that miR-124 down-regulates iASPP expression in 293T cells.

CONCLUSION

The miR-124 levels are down-regulated in ACI patients. The dynamic changes of miR-124 might provide a possible method for the detection of ischemic stroke. Highlights The difference in miR-124 expression levels between ACI patients and normal controls. Dynamic changes of miR-124 expression levels in ACI patients. The down-regulation of miR-124 upon iASPP expression.

Exploring the potential value of miR-148b-3p, miR-151b and miR-27b-3p as biomarkers in acute ischemic stroke

Cerebrovascular disease is the main cause of death in the world. Here, we explored whether circulating serum miR-148b-3p, miR-151b and miR-27b-3p could be as potential diagnostic biomarkers for diagnosing acute ischemic stroke. Seventy-seven IS patients and forty-two healthy controls matched for age and sex were enrolled in the present study. Blood samples were drawn from IS patients within the 24 h. The correlation analysis was performed by Spearman. The ability to distinguish patients from healthy controls was determined by receiver operating characteristic (ROC) curve. The expression of circulating serum miR-148b-3p was significantly decreased, whereas miR-151b and miR-27b-3p were elevated significantly compared with controls. ROC analysis showed area under the ROC curve (AUC) of miR-148b-3p, miR-151b and miR-27b-3p to be 0.6647, 0.6852 and 0.6657, respectively. While the AUC increased to 0.8103 for the combination of miR-148b-3p and miR-27b-3p. Blood miR-151b level was negatively correlated with insulin-like growth factor-1 (IGF-1), and miR-27b-3p level was negatively correlated with IGF-1 and insulin-like growth factor binding protein-3, respectively. Our findings suggest that miR-148b-3p, miR-151b and miR-27b-3p may serve as blood-based biomarkers for diagnosing ischemic stroke patients, and the combination of miR-148b-3p and miR-27b-3p may be more powerful.

Inflammatory Markers and Severity of Intracerebral Hemorrhage

Background and purpose

The pathogenesis of brain injury after intracerebral hemorrhage is thought to be due to mechanical damage followed by ischemic, cytotoxic, and inflammatory changes in the underlying and surrounding tissue.In recent years, there has been a greater research interest into the various inflammatory biomarkers and growth factors that are secreted during intracerebral hemorrhage. The biomarkers investigated in this study are tumor necrosis factor alpha (TNF alpha), C-reactive protein (CRP), homocysteine (Hcy), and vascular endothelial growth factor (VEGF). The aim of this study was to further investigate the effects of these biomarkers in predicting the acute severity outcome of intracerebral hemorrhage (ICH).

Methods

We conducted a retrospective chart review of patients with spontaneous ICH with TNF alpha, CRP, VEGF, and Hcy levels drawn on admission. Forty-two patients with spontaneous ICH with at least one of the above labs were included in the study. Primary outcomes included death, Glasgow Coma Scale (GCS) on admission, early neurologic decline (END), and hemorrhage size. Secondary outcomes included GCS on discharge, ICH score, functional outcome risk stratification scale of intracerebral hemorrhage (FUNC score), change in hemorrhage size, need for surgical intervention, and length of intensive care unit (ICU) stay.

Results

Forty-two patients with spontaneous intracerebral hemorrhage (ICH) were analyzed, 12 patients (28.5%) required surgical intervention, and four patients (9.5%) died. Only low VEGF serum values were found to predict mortality. TNF alpha, CRP, Hcy, and VEGF levels in our patients with ICH were not found to predict early neurologic decline and were not correlated with GCS on admission, initial hemorrhage size, change in hemorrhage size, need for surgical intervention, ICH score, FUNC score, midline shift, and length of ICU stay. CRP and Hcy were elevated in 58% and 31% of patients tested, respectively. GCS on admission and ICH score were significantly associated with mortality.

Conclusion

After careful statistical review of the data obtained from this patient population, only low VEGF values were found to be a significant predictor of mortality. However, elevated CRP and Hcy levels were associated with a non-significant trend in hemorrhage size and mortality suggesting that CRP and Hcy-lowering therapies may decrease hemorrhagic stroke risk and severity.

Long-Zhi Decoction Medicated Serum Promotes Angiogenesis in Human Umbilical Vein Endothelial Cells Based on Autophagy

Ischemic stroke (IS) is a fatal subtype of stroke that lacks effective treatments. Angiogenesis following IS is an effective response that mediates brain recovery and repair. Our previous study demonstrated that long-zhi decoction (LZD), a Chinese herbal formula, promoted angiogenesis in rats of IS model. To further investigate the association between the proangiogenic mechanism of an LZD-medicated serum and cellular autophagy, we evaluated its promotional effect on angiogenesis in human umbilical vein endothelial cells (HUVECs) in vitro. We used HUVECs subjected to H₂O₂ to induce injury and observed the effects of the LZD-medicated serum treatment. Cell-based assays included proliferation, migration, and tube formation. To assess the extent of autophagy, transmission electron microscopy was used to measure the number of autophagosomes. Immunofluorescence and Western blotting were performed to evaluate the autophagy-related protein of LC3-II and Beclin-1. The LZD-medicated serum promoted proliferation, migration, and tube formation in HUVECs. The LZD-medicated serum also increased the autophagosomes and the autophagic protein expressions of LC3-II and Beclin-1. The proangiogenic and autophagic activity of LZD provides new cogitations to its clinical application and may lead to potential drug development for treating various vascular diseases, especially in the elderly, in the future.

Cell-free DNA as a biomarker in stroke: Current status, problems and perspectives

There is currently no proposed stroke biomarker with consistent application in clinical practice. A number of studies have examined cell-free DNA (cfDNA), which circulates in biological fluids during stroke, as a potential biomarker of this disease. The data available suggest that dynamically-determined levels of blood cfDNA may provide new prognostic information for assessment of stroke severity and outcome. However, such an approach has its own difficulties and limitations. This review covers the potential role of cfDNA as a biomarker in stroke, and includes evidence from both animal models and clinical studies, protocols used to analyze cfDNA, and hypotheses on the origin of cfDNA.

Single Cell Immuno-Laser Microdissection Coupled to Label-Free Proteomics to Reveal the Proteotypes of Human Brain Cells After Ischemia

Cerebral ischemia entails rapid tissue damage in the affected brain area causing devastating neurological dysfunction. How each component of the neurovascular unit contributes or responds to the ischemic insult in the context of the human brain has not been solved yet. Thus, the analysis of the proteome is a straightforward approach to unraveling these cell proteotypes. In this study, post-mortem brain slices from ischemic stroke patients were obtained corresponding to infarcted (IC) and contralateral (CL) areas. By means of laser microdissection, neurons and blood brain barrier structures (BBB) were isolated and analyzed using label-free quantification. MS data are available via ProteomeXchange with identifier PXD003519. Ninety proteins were identified only in neurons, 260 proteins only in the BBB and 261 proteins in both cell types. Bioinformatics analyses revealed that repair processes, mainly related to synaptic plasticity, are outlined in microdissected neurons, with nonexclusive important functions found in the BBB. A total of 30 proteins showing p < 0.05 and fold-change> 2 between IC and CL areas were considered meaningful in this study: 13 in neurons, 14 in the BBB and 3 in both cell types. Twelve of these proteins were selected as candidates and analyzed by immunohistofluorescence in independent brains. The MS findings were completely verified for neuronal SAHH2 and SRSF1 whereas the presence in both cell types of GABT and EAA2 was only validated in neurons. In addition, SAHH2 showed its potential as a prognostic biomarker of neurological improvement when analyzed early in the plasma of ischemic stroke patients. Therefore, the quantitative proteomes of neurons and the BBB (or proteotypes) after human brain ischemia presented here contribute to increasing the knowledge regarding the molecular mechanisms of ischemic stroke pathology and highlight new proteins that might represent putative biomarkers of brain ischemia or therapeutic targets.

Kinin B1 receptor as a novel, prognostic progression biomarker for carotid atherosclerotic plaques

Stroke caused by atherosclerosis remains a leading cause of morbidity and mortality worldwide, associated with carotid plaque rupture and inflammation progression. However, the inflammatory biomarkers which aid in predicting the future course of plaques are less detailed. The present study investigated the association between plaque vulnerable and inflammatory biomarkers using blood and plaque specimens. Carotid plaque specimens were obtained from 80 patients following stroke, 14 patients suffering from transient ischaemic attack and 17 asymptomatic patients that underwent carotid endarterectomy. To assess changes in plaque characteristics at histological levels, plaques were categorized by the time between the latest ischemic stroke and surgical intervention within 30, 30‑90, 90‑180 and over 180 days following stroke. Serum levels of inflammatory biomarkers interleukin (IL)‑6, IL‑10 and kinin B1 receptor (B1R) were measured by ELISA. Histological assessment of plaque was used to evaluate the plaque stability, progression and the inflammatory biomarker levels. Comparisons of histological characteristics demonstrated that plaques revealed an unstable phenotype following stroke within 30, 30‑90 days and then remodeled into more stable plaques following stroke at 90‑180 and over 180 days. By comparing the serum levels of inflammatory biomarkers, it was observed that IL‑6 and B1R levels tended to decline whereas IL‑10 levels increased in stroke patients from <30 days to over 180 days. Immunohistochemical analysis of IL‑6, IL‑10 and B1R demonstrated similar alterations in serum levels. Correlation analyses revealed that only B1R serum level was significantly correlated with histological level in patients with carotid atherosclerosis. The findings revealed that serum B1R levels may provide prognostic information and currently act as potential indicators for progression in atherosclerosis.

Alzheimer's Disease and Paraoxonase 1 (PON1) Gene Polymorphisms

BACKGROUND

Some studies have indicated that human paraoxonase 1 (PON1) activity shows a polymorphic distribution. The aim of this study was to determine the distribution of PON1 polymorphism in patients with Alzheimer's disease in Gorgan and compare it with a healthy control group.

METHOD

The study included 100 healthy individuals and 50 patients. Enzyme activity and genetic polymorphism of PON1 were determined.

RESULT

There were significant differences in distribution of genotypes and alleles among patients and control group. The most common genotype was CT in patients and control group, while the most frequent alleles were T and C in patients and controls, respectively. There was a statistically significant variation between serum PON1 activity and -108C> T polymorphism. The highest PON1 enzyme activities in the patients and controls were found in CC, while lower enzyme activities were seen in CT and TT genotypes in both genders and age groups.

CONCLUSION

Onset of Alzheimer's disease may depend on different polymorphisms of the PON1 enzyme. Late or early-onset of Alzheimer's disease may also depend on age and gender distribution, especially for arylesterase enzyme. Further studies on polymorphism of the enzyme are necessary for interpretation of possible polymorphic effects of enzyme on PON1 activity in humans.

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.

Blood biomarkers in the early stage of cerebral ischemia

In ischemic stroke patients, blood-based biomarkers may be applied for the diagnosis of ischemic origin and subtype, prediction of outcomes and targeted treatment in selected patients. Knowledge of the pathophysiology of cerebral ischemia has led to the evaluation of proteins, neurotransmitters, nucleic acids and lipids as potential biomarkers. The present report focuses on the role of blood-based biomarkers in the early stage of ischemic stroke-within 72h of its onset-as gleaned from studies published in English in such patients. Despite growing interest in their potential role in clinical practice, the application of biomarkers for the management of cerebral ischemia is not currently recommended by guidelines. However, there are some promising clinical biomarkers, as well as the N-methyl-d-aspartate (NMDA) peptide and NMDA-receptor (R) autoantibodies that appear to identify the ischemic nature of stroke, and the glial fibrillary acidic protein (GFAP) that might be able to discriminate between acute ischemic and hemorrhagic strokes. Moreover, genomics and proteomics allow the characterization of differences in gene expression, and protein and metabolite production, in ischemic stroke patients compared with controls and, thus, may help to identify novel markers with sufficient sensitivity and specificity. Additional studies to validate promising biomarkers and to identify novel biomarkers are needed.

Inter-rater agreement analysis of the Precise Diagnostic Score for suspected transient ischemic attack

Background

No definitive criteria are available to confirm the diagnosis of transient ischemic attack. Inter-rater agreement between physicians regarding the diagnosis of transient ischemic attack is low, even among vascular neurologists. We developed the Precise Diagnostic Score, a diagnostic score that consists of discrete and well-defined clinical and imaging parameters, and investigated inter-rater agreement in patients with suspected transient ischemic attack.

Methods

Fellowship-trained vascular neurologists, blinded to final diagnosis, independently reviewed retrospectively identical history, physical examination, routine diagnostic studies, and brain magnetic resonance imaging (diffusion and perfusion images) from consecutive patients with suspected transient ischemic attack. Each patient was rated using the 8-point Precise Diagnostic Score score, composed of a clinical score (0–4 points) and an imaging score (0–4 points). The composite Precise Diagnostic Score determines a Precise Diagnostic Score Likelihood of Brain Ischemia Scale: 0–1 = unlikely, 2 = possible, 3 = probable, 4–8 = very likely.

Results

Three raters reviewed data from 114 patients. Using Precise Diagnostic Score, all three raters scored a similar percentage of the clinical events as being “probable” or “very likely” caused by brain ischemia: 57, 55, and 58%. Agreement was high for both total Precise Diagnostic Score (intraclass correlation coefficient of 0.94) and for the Likelihood of Brain Ischemia Scale (agreement coefficient of 0.84).

Conclusions

Compared with prior studies, inter-rater agreement for the diagnosis of transient brain ischemia appears substantially improved with the Precise Diagnostic Score scoring system. This score is the first to include specific criteria to assess the clinical relevance of diffusion-weighted imaging and perfusion lesions and supports the added value of magnetic resonance imaging for assessing patients with suspected transient ischemic attack.

Serum Phenylalanine, Tyrosine, and their Ratio in Acute Ischemic Stroke: on the Trail of a Biomarker?

Fast diagnosis and appropriate treatment are of utmost importance to improving the outcome in patients with acute ischemic stroke (AIS). A rapid and sensitive blood test for ischemic stroke is required. The aim of this study was to examine the usefulness of phenylalanine (PHE) and tyrosine (TYR) as diagnostic biomarkers in AIS. Serum levels of PHE and TYR, measured using HPLC, and their ratio (PHE/TYR) were compared between 45 patients with AIS and 40 healthy control subjects. The relationship between PHE/TYR and the serum levels of several cytokines were also examined. PHE/TYR was significantly higher in AIS patients than in healthy controls (1.75 vs 1.24, p < 0.001). A receiver operating characteristic (ROC) curve analysis of PHE/TYR in AIS patients relative to healthy controls revealed promising sensitivity and specificity, which at an optimal cutoff of 1.45 were 76 and 85 %, respectively. PHE/TYR was positively correlated with interleukin (IL)-1β (r = 0.37, p = 0.011) and IL-6 (r = 0.33, p = 0.025). This study shows that PHE/TYR is highly elevated in the acute phase of AIS, and that this elevation is coupled to the inflammatory response. The ROC analysis documents the possible value of PHE/TYR as a biomarker for AIS and demonstrates its clinical potential as a blood-based test for AIS.

Role of N-terminal pro-B-type natriuretic peptide, high-sensitivity C-reactive protein, and inteleukin-6 in predicting a poor outcome after a stroke

OBJECTIVE

N-terminal pro-B-type natriuretic peptide (NT-proBNP), high-sensitivity C-reactive protein (hsCRP), and interleukin-6 (IL-6) concentrations can be important biomarkers in the acute stroke setting. In acute ischemic and hemorrhagic stroke patients, we investigated the association of NT-proBNP, hsCRP, and IL-6 serum concentrations with stroke severity and functional and cognitive outcomes at discharge.

METHODS

Seventy-eight patients (53 men; median age 72 years) admitted with ischemic or hemorrhagic stroke within 48 h of symptom onset were evaluated for clinical stroke severity (Scandinavian stroke scale; SSS), functional status before the stroke (modified Rankin scale; mRS), and cerebrovascular disease risk factors. Cognitive (Mini Mental State Examination) and functional (mRS) outcomes were evaluated at hospital discharge. Blood samples were drawn for the assessment of NT-proBNP, hsCRP, and IL-6 concentrations within 24 h of admission.

RESULTS

Greater NT-proBNP and hsCRP serum concentrations were associated with greater clinical stroke severity, adjusting for the patients' gender, age, stroke type, mRS score on admission, and presence of heart failure (β = -0.292, p = 0.012; β = -0.303, p = 0.009). In multivariate adjusted regression models with IL-6, hsCRP, and NT-proBNP considered together, IL-6 and hsCRP remained associated with worse functional (β = 0.210, p = 0.022) and cognitive (β = -0.269, p = 0.014) outcomes at discharge, respectively. In receiver operating characteristic analyses, the investigated blood biomarkers produced a minimal increase in predictive values for outcomes at discharge above the SSS score, age, and gender.

CONCLUSIONS

In acute stroke patients, greater NT-proBNP and hsCRP serum concentrations are independently associated with greater clinical stroke severity. Elevated concentrations of IL-6 and hsCRP are associated with worse functional and cognitive outcomes at discharge, respectively.

Inductive and Deductive Approaches to Acute Cell Injury

Many clinically relevant forms of acute injury, such as stroke, traumatic brain injury, and myocardial infarction, have resisted treatments to prevent cell death following injury. The clinical failures can be linked to the currently used inductive models based on biological specifics of the injury system. Here we contrast the application of inductive and deductive models of acute cell injury. Using brain ischemia as a case study, we discuss limitations in inductive inferences, including the inability to unambiguously assign cell death causality and the lack of a systematic quantitative framework. These limitations follow from an overemphasis on qualitative molecular pathways specific to the injured system. Our recently developed nonlinear dynamical theory of cell injury provides a generic, systematic approach to cell injury in which attractor states and system parameters are used to quantitatively characterize acute injury systems. The theoretical, empirical, and therapeutic implications of shifting to a deductive framework are discussed. We illustrate how a deductive mathematical framework offers tangible advantages over qualitative inductive models for the development of therapeutics of acutely injured biological systems.

Paraoxonase 1 in neurological disorders

Paroxonase 1 displays multiple physiological activities that position it as a putative player in the pathogenesis of neurological disorders. Here we reviewed the literature focusing on the role of paraoxonase 1 (PON1) as a factor in the risk of stroke and the major neurodegenerative diseases. PON1 activity is reduced in stroke patients, which significantly correlates inversely with carotid and cerebral atherosclerosis. The presence of the R allele of the Q192R PON1 polymorphism seems to potentiate this risk for stroke. PON1 exerts peroxidase activities that may be important in neurodegenerative disorders associated with oxidative stress. PON1 is also a key detoxifier of organophosphates and organophosphate exposure has been linked to the development of neurological disorders in which acetylcholine plays a significant role. In Parkinson's disease most of the studies suggest no participation of either L55M or the Q192R polymorphisms in its pathogenesis. However, many studies suggest that the MM55 PON1 genotype is associated with a higher risk for Parkinson's disease in individuals exposed to organophosphates. In Alzheimer's disease most studies have failed to find any association between PON1 polymorphisms and the development of the disease. Some studies show that PON1 activity is decreased in patients with Alzheimer's disease or other dementias, suggesting a possible protective role of PON1. No links between PON1 polymorphisms or activity have been found in other neurodegenerative diseases such as multiple sclerosis and amyotrophic lateral sclerosis. PON1 is a potential player in the pathogenesis of several neurological disorders. More research is warranted to ascertain the precise pathogenic links and the prognostic value of its measurement in neurological patients.