Blood Of Stroke Patients Research Articles

Dynamics of changes in the representation of mesenchymal cells in the forming glial scar during dexamethasone application

Mesenchymal stem cells are involved in cellular responses in the injured brain after a stroke. The formation of a glial scar is a local response in the brain to damage, and mesenchymal stem cells may be involved in the processes of scar formation. Mesenchymal stem cells express a range of membrane markers, the expression profile of which obviously changes as they differentiate and depends on the microenvironment in which these cells are located. However, it is still unclear where the stem cells in the damaged brain originate from – whether they come from a resident source or from the bone marrow, although an increase in CD34+ cells in the blood of stroke patients is a well-known fact. In this study, we consider the hypothesis regarding the appearance of mesenchymal stem cells in the brain during a stroke and their potential involvement in the formation of a glial scar. The aim of the study is to investigate the involvement of CD44+, CD68+, CD90+, and CD146+ cells in the formation of a glial scar during hemorrhagic stroke and the changes in their representation under the effect of dexamethasone. To achieve this goal, we simulated hemorrhagic stroke in rats and compared the results of immunohistochemical detection of CD44+, CD68+, CD90+, and CD146+ cells in the area of glial scar formation against the dexamethasone administration. We obtained convincing results of differences in the activity and timing of migration of cells expressing CD44 compared to cells expressing CD68, CD90, and CD146. There is a tendency indicating a dependence between the detection of CD44+ cells and the extent of the damage, while the detection of CD68+, CD90+, and CD146+ cells is strongly correlated and increases under the effect of dexamethasone. Cells expressing CD44 were the main participants in the infiltrating pool of cells in the acute phase, but dexamethasone delayed the peak accumulation of CD44+ cells in the forming scar. There were some changes in the detection of these cells around the hemorrhage during dexamethasone treatment, which may indicate its modulating effect on mesenchymal stem cells during glial scar formation. The more frequent detection of CD68+, CD90+, and CD146+ cells can be considered a manifestation of the potential modification by dexamethasone of cellular reactions involved in glial scar formation in the brain after a stroke. The study of the roles of specific immunophenotypes of mesenchymal stem cells in the areas of glial scar formation following hemorrhagic stroke opens new perspectives in the study of brain recovery processes.

Neurofilament Light Chain (NfL) in Blood-A Biomarker Predicting Unfavourable Outcome in the Acute Phase and Improvement in the Late Phase after Stroke.

Increased sensitivity of methods assessing the levels of neurofilament light chain (NfL), a neuron-specific intermediate filament protein, in human plasma or serum, has in recent years led to a number of studies addressing the utility of monitoring NfL in the blood of stroke patients. In this review, we discuss that elevated blood NfL levels after stroke may reflect several different neurobiological processes. In the acute and post-acute phase after stroke, high blood levels of NfL are associated with poor clinical outcome, and later on, the blood levels of NfL positively correlate with secondary neurodegeneration as assessed by MRI. Interestingly, increased blood levels of NfL in individuals who survived stroke for more than 10 months were shown to predict functional improvement in the late phase after stroke. Whereas in the acute phase after stroke the injured axons are assumed to be the main source of blood NfL, synaptic turnover and secondary neurodegeneration could be major contributors to blood NfL levels in the late phase after stroke. Elevated blood NfL levels after stroke should therefore be interpreted with caution. More studies addressing the clinical utility of blood NfL assessment in stroke patients are needed before the inclusion of NfL in the clinical workout as a useful biomarker in both the acute and the chronic phase after stroke.

Analysis of TGF-β1 and p53 Expression in The Blood of Stroke Patient

Introduction: Stroke is a dysfunction of brain tissue due to deficiency of blood circulation to the brain. This causes disruption of blood supply and oxygen in the brain. Stroke not only needs to be handled in post-event, but also needs to be understood the cause of the occurrence by molecular, so that the drug will be right on target. Inflammation is associated as a secondary injury mechanism in the case of stroke. Dendritic cells which secreted TGF-β, it functions to regulate proliferation, differentiation and activate other cytokines in cell growth. It is strongly suspected that Transforming Growth Factor-β1 (TGF-ß1) is a determinant of cytokines in nerve tissue recovery. Neural cell malfunction or nerve cell death is thought to be the role of p53 protein.Methods: The design of this research is observation. This research measures TGF and p53 expression in the stages of mRNA (RT-PCR) and protein (ELISA) in the blood of stroke patients.Results: The expression of TGF- β1 and p53 mRNA in the blood of stroke patients is higher (50 and 45 times; Unpaired p <0.01) than normal. TGF- β and p53 protein levels in the blood of stroke patients are higher than normal (20,607 vs 1,895 pg/mLx10; 44,418 vs 11.63 pg/ mL; Unpaired 0 <0.01). The correlation of both TGF- β1 and p53 shows a strong positive.Discussion: The expression of increased TGF- β1 and p53 In the blood of stroke patients.International Journal of Human and Health Sciences Vol. 05 No. 01 January’21 Page: 35-40

MiR-34a and stroke: Assessment of non-modifiable biological risk factors in cerebral ischemia

Aging of the nervous system, and the occurrence of age-related brain diseases such as stroke, are associated with changes to a variety of cellular processes controlled by many distinct genes. MicroRNAs (miRNAs), short non-coding functional RNAs that can induce translational repression or site-specific cleavage of numerous target mRNAs, have recently emerged as important regulators of cellular senescence, aging, and the response to neurological insult. Here, we focused on the assessment of the role of miR-34a in stroke. We noted increases in miR-34a expression in the blood of stroke patients as well as in blood and brain of mice subjected to experimental stroke. Our methodical genetic manipulation of miR-34a expression substantially impacted stroke-associated preclinical outcomes and we have in vitro evidence that these changes may be driven at least in part by disruptions to blood brain barrier integrity and mitochondrial oxidative phosphorylation in endothelial cells. Finally, aging, independent of brain injury, appears to be associated with shifts in circulating miRNA profiles. Taken together, these data support a role for miRNAs, and specifically miR-34a, in brain aging and the physiological response to age-related neurological insult, and lay the groundwork for future investigation of this novel therapeutic target.

Identification of novel blood biomarker panels to detect ischemic stroke in patients and their responsiveness to therapeutic intervention

The use of blood biomarkers for stroke has been long considered an excellent method to determine the occurrence, timing, subtype, and severity of stroke. In this study, venous blood was obtained from ischemic stroke patients after stroke onset and compared with age and sex-matched controls. We used a multiplex panel of 37 inflammatory molecules, analyzed using Luminex MagPix technology, to identify the changes in plasma proteins after ischemic stroke. We identified eight key molecules that were altered within the blood of stroke patients as compared to controls. Plasma levels of interleukin 6 signal transducer (sIL-6Rβ/gp130), matrix metalloproteinase-2 (MMP-2), osteopontin, sTNF-R1 and sTNF-R2 were significantly higher in stroke patients compared to controls. Interferon-β, interleukin-28, and thymic stromal lymphopoietin (TSLP) were decreased in plasma from stroke patients. No other immunological markers were significantly different between patient groups. When stroke patients were treated with tissue plasminogen activator (t-PA), plasma levels of interferon-α2 significantly increased while interleukin-2 and pentraxin-3 decreased. The discriminatory power of the molecules was evaluated by receiver operating characteristic (ROC) analysis. According to ROC analysis, the best markers for distinguishing stroke occurrence were MMP-2 (AUC = 0.76, sensitivity 62.5%, specificity 88.5%), sTNF-R2 (AUC = 0.75, sensitivity 83.3%, specificity 65.3%) and TSLP (AUC = 0.81, sensitivity 66.7%, specificity 96.2%). Multivariate logistic regression, used to evaluate the combination of proteins, identified a biomarker panel with high specificity and sensitivity (AUC = 0.96, sensitivity 87.5%, specificity 96.2%). These results indicate a novel set of blood biomarkers that could be used in a panel to identify stroke patients and their responsiveness to therapeutic intervention.

Contraction of Blood Clots Is Impaired in Acute Ischemic Stroke.

Obstructive thrombi or thrombotic emboli are the pathogenic basis of ischemic stroke. In vitro blood clots and in vivo thrombi can undergo platelet-driven contraction (retraction), resulting in volume shrinkage. Clot contraction can potentially reduce vessel occlusion and improve blood flow past emboli or thrombi. The aim of this work was to examine a potential pathogenic role of clot contraction in ischemic stroke. We used a novel automated method that enabled us to quantify time of initiation and extent and rate of clot contraction in vitro. The main finding is that clot contraction from the blood of stroke patients was reduced compared with healthy subjects. Reduced clot contraction correlated with a lower platelet count and their dysfunction, higher levels of fibrinogen and hematocrit, leukocytosis, and other changes in blood composition that may affect platelet function and properties of blood clots. Platelets from stroke patents were spontaneously activated and displayed reduced responsiveness to additional stimulation. Clinical correlations with respect to severity and stroke pathogenesis suggest that the impaired clot contraction has the potential to be a pathogenic factor in ischemic stroke. The changeable ability of clots and thrombi to shrink in volume may be a novel unappreciated mechanism that aggravates or alleviates the course and outcomes of ischemic stroke. The clinical importance of clot or thrombus transformations in vivo and the diagnostic and prognostic value of this blood test for clot contraction need further exploration.

Crosstalk between miRNAs and their regulated genes network in stroke.

In recent years, more and more studies focus on the roles of genes or miRNAs in stroke. However, the molecular mechanism connecting miRNAs and their targetgenes remains unclear. The aim of this study was to determine the differential regulation and correlations between miRNAs and their targetgenes in human stroke. Stroke-related miRNAs were obtained from the Human MicroRNA Disease Database (HMDD) and their targetgenes were generated from three independent sources. Kappa score was used to create the network and the functional modules. A total of 11 stroke-related miRNAs were identified from the HMDD and 441 overlapping targetgenes were extracted from the three databases. By network construction and GO analysis, 13 functional modules, 186 biological processes, and 21 pathways were found in the network, of which functional module 8 was the largest module, cellular-related process and phosphate-related process were the most important biological processes, and MAPK signaling pathway was the most significant pathway. In our study, all miRNAs regulate the stroke modular network by their targetgenes. After the validation of miRNAs, we found that miR-605 and miR-181d were highly expressed in the blood of stroke patients which never reported before may supply novel target for treatment.

Polarizing the immune system towards neuroprotection in brain ischemia.

The development of ischemic brain damage is dramatically affected by the immune system, whose activation occurs immediately after the insult and may last for several days, involving a complex interplay between soluble and cellular mediators (Amantea et al., 2015). Accordingly, recent expression profiling studies have revealed that the majority of the genes modulated in the blood of stroke patients participate in the regulation of innate immune responses (Brooks et al., 2014). Moreover, in the clinical setting, serum levels of markers of acute inflammation correlate with the severity of ischemic brain damage and neurological deficit.

Intracerebral Hemorrhage and Ischemic Stroke of Different Etiologies Have Distinct Alternatively Spliced mRNA Profiles in the Blood: a Pilot RNA-seq Study

Whole transcriptome studies have used 3′-biased expression microarrays to study genes regulated in the blood of stroke patients. However, alternatively spliced messenger RNA isoforms have not been investigated for ischemic stroke or intracerebral hemorrhage (ICH) in animals or humans. Alternative splicing is the mechanism whereby different combinations of exons of a single gene produce distinct mRNA and protein isoforms. Here, we used RNA sequencing (RNA-seq) to determine if alternative splicing differs for ICH and cardioembolic, large vessel and lacunar causes of ischemic stroke compared to controls. RNA libraries from 20 whole blood samples were sequenced to 200 M 2 × 100 bp reads using Illumina sequencing-by-synthesis technology. Differential alternative splicing was assessed using one-way analysis of variance (ANOVA), and differential exon usage was calculated. Four hundred twelve genes displayed differential alternative splicing among the groups (false discovery rate, FDR; p < 0.05). They were involved in cellular immune response, cell death, and cell survival pathways. Distinct expression signatures based on usage of 308 exons (292 genes) differentiated the groups (p < 0.0005; fold change >|1.2|). This pilot study demonstrates that alternatively spliced genes from whole blood differ in ICH compared to ischemic stroke and differ between different ischemic stroke etiologies. These results require validation in a separate cohort.Electronic supplementary materialThe online version of this article (doi:10.1007/s12975-015-0407-9) contains supplementary material, which is available to authorized users.

Antigen-specific immune reactions to ischemic stroke.

Brain proteins are detected in the cerebrospinal fluid (CSF) and blood of stroke patients and their concentration is related to the extent of brain damage. Antibodies against brain antigens develop after stroke, suggesting a humoral immune response to the brain injury. Furthermore, induced immune tolerance is beneficial in animal models of cerebral ischemia. The presence of circulating T cells sensitized against brain antigens, and antigen presenting cells (APCs) carrying brain antigens in draining lymphoid tissue of stroke patients support the notion that stroke might induce antigen-specific immune responses. After stroke, brain proteins that are normally hidden from the periphery, inflammatory mediators, and danger signals can exit the brain through several efflux routes. They can reach the blood after leaking out of the damaged blood-brain barrier (BBB) or following the drainage of interstitial fluid to the dural venous sinus, or reach the cervical lymph nodes through the nasal lymphatics following CSF drainage along the arachnoid sheaths of nerves across the nasal submucosa. The route and mode of access of brain antigens to lymphoid tissue could influence the type of response. Central and peripheral tolerance prevents autoimmunity, but the actual mechanisms of tolerance to brain antigens released into the periphery in the presence of inflammation, danger signals, and APCs, are not fully characterized. Stroke does not systematically trigger autoimmunity, but under certain circumstances, such as pronounced systemic inflammation or infection, autoreactive T cells could escape the tolerance controls. Further investigation is needed to elucidate whether antigen-specific immune events could underlie neurological complications impairing recovery from stroke.

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

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

Blood Glutathione S-Transferase-π as a Time Indicator of Stroke Onset

BackgroundAbility to accurately determine time of stroke onset remains challenging. We hypothesized that an early biomarker characterized by a rapid increase in blood after stroke onset may help defining better the time window during which an acute stroke patient may be candidate for intravenous thrombolysis or other intravascular procedures.MethodsThe blood level of 29 proteins was measured by immunoassays on a prospective cohort of stroke patients (N = 103) and controls (N = 132). Mann-Whitney U tests, ROC curves and diagnostic odds ratios were applied to evaluate their clinical performances.ResultsAmong the 29 molecules tested, GST-π concentration was the most significantly elevated marker in the blood of stroke patients (p<0.001). More importantly, GST-π displayed the best area under the curve (AUC, 0.79) and the best diagnostic odds ratios (10.0) for discriminating early (N = 22, <3 h of stroke onset) vs. late stroke patients (N = 81, >3 h after onset). According to goal-oriented distinct cut-offs (sensitivity(Se)-oriented: 17.7 or specificity(Sp)-oriented: 65.2 ug/L), the GST-π test obtained 91%Se/50%Sp and 50%Se/91%Sp, respectively. Moreover, GST-π showed also the highest AUC (0.83) and performances for detecting patients treated with tPA (N = 12) compared to ineligible patients (N = 103).ConclusionsThis study demonstrates that GST-π can accurately predict the time of stroke onset in over 50% of early stroke patients. The GST-π test could therefore complement current guidelines for tPA administration and potentially increase the number of patients accessing thrombolysis.

Functional Status of Peripheral Blood T-Cells in Ischemic Stroke Patients

Stroke is a major cause of disability and leading cause of death in the northern hemisphere. Only recently it became evident that cerebral ischemia not only leads to brain tissue damage and subsequent local inflammation but also to a dramatic loss of peripheral blood T-cells with subsequent infections. However, only scarce information is available on the activation status of surviving T cells. This study therefore addressed the functional consequences of immunological changes induced by stroke in humans. For this purpose peripheral blood T-cells were isolated from 93 stroke patients and the expression of activation makers was determined. In addition ex vivo stimulation assays were applied to asses the functionality of T cells derived from blood of stroke patients. Compared to healthy controls, stroke patients demonstrated an enhanced surface expression of HLA-DR (p<0.0001) and CD25 (p = 0.02) on T cells, revealing that stroke leads to T cell activation, while CTLA-4 remained undetectable. In vitro studies revealed that catecholamines inhibit CTLA-4 upregulation in activated T cells. Ex vivo, T cells of stroke patients proliferated unimpaired and released increased amounts of the proinflammatory cytokine TNF-α (p<0.01) and IL-6 (p<0.05). Also, in sera of stroke patients HMGB1 concentrations were increased (p = 0.0002). The data demonstrate that surviving T cells in stroke patients remain fully functional and are primed towards a TH1 response, in addition we provide evidence that catecholamine mediated inhibition of CTLA-4 expression and serum HMGB1 release are possible mediators in stroke induced activation of T cells.

Detection of Chlamydia pneumoniae in blood of stroke patients

Detection of Chlamydia pneumoniae in blood of stroke patients

Increased cytokine release from peripheral blood cells after acute stroke.

Cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha can play pathogenetic or protective roles in stroke. They are increased in the brain after experimental ischemia and in the CSF of patients with stroke. However, their presence in the periphery is still controversial. To determine the source and time-course of cytokines in blood of stroke patients, IL-6 and TNF-alpha release from blood cells and serum levels were determined in 40 patients on days 1 through 2, 4, 10, 30, and 90 after stroke. Twenty healthy age-matched volunteers were used as controls. IL-6 and TNF-alpha release from stimulated blood cells was increased in stroke patients, compared to controls. A peak response (+224%) was observed at day 4 for IL-6, while TNF-alpha release was largely and significantly increased (about three-fold compared to controls) from day 1 to 2 until day 90 after stroke. The increase in IL-6 release was significantly higher in ischemic, compared to hemorrhagic strokes, at days 1 and 4. Circulating IL-6 was increased at each time point. The ischemic processes in the CNS induces a long-lasting activation of IL-6 and TNF-alpha production in peripheral blood cells, which are a major source of serum cytokines after stroke.