Pathophysiology Of Ischemic Stroke Research Articles

Monocyte Transmodulation: The Next Novel Therapeutic Approach in Overcoming Ischemic Stroke?

The immune response following neuroinflammation is a vital element of ischemic stroke pathophysiology. After the onset of ischemic stroke, a specialized vasculature system that effectively protects central nervous system tissues from the invasion of blood cells and other macromolecules is broken down within minutes, thereby triggering the inflammation cascade, including the infiltration of peripheral blood leukocytes. In this series of processes, blood-derived monocytes have a significant effect on the outcome of ischemic stroke through neuroinflammatory responses. As neuroinflammation is a necessary and pivotal component of the reparative process after ischemic stroke, understanding the role of infiltrating monocytes in the modulation of inflammatory responses may offer a great opportunity to explore new therapies for ischemic stroke. In this review, we discuss and highlight the function and involvement of monocytes in the brain after ischemic injury, as well as their impact on tissue damage and repair.

Pathophysiology of Ischemic Stroke: Role of Oxidative Stress.

Stroke is the second leading cause of mortality and the major cause of adult physical disability worldwide. The currently available treatment to recanalize the blood flow in acute ischemic stroke is intravenous administration of tissue plasminogen activator (t-PA) and endovascular treatment. Nevertheless, those treatments have the disadvantage that reperfusion leads to a highly harmful reactive oxygen species (ROS) production, generating oxidative stress (OS), which is responsible for most of the ischemia-reperfusion injury and thus causing brain tissue damage. In addition, OS can lead brain cells to apoptosis, autophagy and necrosis. The aims of this review are to provide an updated overview of the role of OS in brain IRI, providing some bases for therapeutic interventions based on counteracting the OS-related mechanism of injury and thus suggesting novel possible strategies in the prevention of IRI after stroke.

Role of long noncoding RNA MEG3/miR-378/GRB2 axis in neuronal autophagy and neurological functional impairment in ischemic stroke

Autophagy has been shown to maintain neural system homeostasis during stroke. However, the molecular mechanisms underlying neuronal autophagy in ischemic stroke remain poorly understood. This study aims to investigate the regulatory mechanisms of the pathway consisting of MEG3 (maternally expressed gene 3), microRNA-378 (miR-378), and GRB2 (growth factor receptor-bound protein 2) in neuronal autophagy and neurological functional impairment in ischemic stroke. A mouse model of the middle cerebral artery occluded-induced ischemic stroke and an in vitro model of oxygen-glucose deprivation-induced neuronal injury were developed. To understand the role of the MEG3/miR-378/GRB2 axis in the neuronal regulation, the expression of proteins associated with autophagy in neurons was measured by Western blotting analysis, and neuron death was evaluated using a lactate dehydrogenase leakage rate test. First, it was found that the GRB2 gene, up-regulated in middle cerebral artery occluded-operated mice and oxygen-glucose deprivation-exposed neurons, was a target gene of miR-378. Next, miR-378 inhibited neuronal loss and neurological functional impairment in mice, as well as neuronal autophagy and neuronal death by silencing of GRB2. Confirmatory in vitro experiments showed that MEG3 could specifically bind to miR-378 and subsequently up-regulate the expression of GRB2, which in turn suppressed the activation of Akt/mTOR pathway. Taken together, these findings suggested that miR-378 might protect against neuronal autophagy and neurological functional impairment and proposed that a MEG3/miR-378/GRB2 regulatory axis contributed to better understanding of the pathophysiology of ischemic stroke.

The Difference of Lymphocyte, hs-CRP, and Electroencephalogram with and without Simvastatin in Acute Ischemic Stroke

Mortality and morbidity due to stroke rank the highest in Indonesia (15.4%), and most types of stroke are ischemic (87%). Inflammation has a role in the pathophysiology of both ischemic stroke and also inhibits acute symptomatic epileptic seizures (3-6%) in the first 7 days after stroke. Statins have been used for the treatment of dyslipidemia in stroke patients. Some studies showed that statins reduced the inflammatory response after a stroke and prevented the recovery of epileptic seizures. This study aimed to determine the differences in lymphocytes, hs-CRP, Electroencephalogram (EEG) with and without Simvastatin in acute ischemic stroke. This research was an experimental study with a double-blind, randomized control trial design consisting of two groups, a group given Simvastatin 20 mg/day, and a group given a placebo for seven days. The difference in lymphocytes, hs-CRP, EEG, and epileptic seizures between the two groups were then analyzed. The sample was 26 people, consisting of 17 (65.4%) males and 9 (34.6%) females with an average age of 59±5.8 years. Chi-Square and Fisher's test showed a significant difference in hs-CRP (p=0.005) and epileptic seizures (p=0.015), but no significant difference in lymphocytes (p=0.336) and EEG (p=0.42) between groups given Simvastatin 20 mg/day and those given placebo. There was a significant difference in hs-CRP and epileptic seizures, but no significant difference in lymphocyte count and EEG between the two groups with and without Simvastatin administration.

Uric Acid Neuroprotection Associated to IL-6/STAT3 Signaling Pathway Activation in Rat Ischemic Stroke.

Despite the promising neuroprotective effects of uric acid (UA) in acute ischemic stroke, the seemingly pleiotropic underlying mechanisms are not completely understood. Recent evidence points to transcription factors as UA targets. To gain insight into the UA mechanism of action, we investigated its effects on pertinent biomarkers for the most relevant features of ischemic stroke pathophysiology: (1) oxidative stress (antioxidant enzyme mRNAs and MDA), (2) neuroinflammation (cytokine and Socs3 mRNAs, STAT3, NF-κB p65, and reactive microglia), (3) brain swelling (Vegfa, Mmp9, and Timp1 mRNAs), and (4) apoptotic cell death (Bcl-2, Bax, caspase-3, and TUNEL-positive cells). Adult male Wistar rats underwent intraluminal filament transient middle cerebral artery occlusion (tMCAO) and received UA (16mg/kg) or vehicle (Locke's buffer) i.v. at 20min reperfusion. The outcome measures were neurofunctional deficit, infarct, and edema. UA treatment reduced cortical infarct and brain edema, as well as neurofunctional impairment. In brain cortex, increased UA: (1) reduced tMCAO-induced increases in Vegfa and Mmp9/Timp1 ratio expressions; (2) induced Sod2 and Cat expressions and reduced MDA levels; (3) induced Il6 expression, upregulated STAT3 and NF-κB p65 phosphorylation, induced Socs3 expression, and inhibited microglia activation; and (4) ameliorated the Bax/Bcl-2 ratio and induced a reduction in caspase-3 cleavage as well as in TUNEL-positive cell counts. In conclusion, the mechanism for morphological and functional neuroprotection by UA in ischemic stroke is multifaceted, since it is associated to activation of the IL-6/STAT3 pathway, attenuation of edematogenic VEGF-A/MMP-9 signaling, and modulation of relevant mediators of oxidative stress, neuroinflammation, and apoptotic cell death.

Pathophysiology, Mechanism, and Outcome of Ischemic Stroke in Cancer Patients

ObjectivesThe purpose of this study is to assess the risk factors, biomarkers of stroke, mechanism, and outcomes of cerebral infarction among cancerous diseases. Materials & Methods156 patients presented by acute ischemic stroke were divided into two groups: the first group included 78 ischemic stroke patients associated with different types of cancer and the second group (control group) included 78 ischemic stroke patients not associated with cancer. Both groups were compared regarding the risk factors, previous thrombotic activity, subtypes, biomarkers of stroke, and outcomes. ResultsCancer patients presented by acute ischemic stroke were accompanied by a significantly less incidence of diabetes mellitus, hypertension, dyslipidemia, and coronary heart disease, and atrial fibrillation than non-cancer patients (P < 0.001). While, levels of biomarkers of inflammation like erythrocyte sedimentation rate and C-reactive protein, and stroke biomarkers like fibrinogen, and D-dimer, all together were highly elevated in cancerous disease group of patients (P < 0.01). The prevalence of deep vein thrombosis, pulmonary embolism, and myocardial infarction was significantly higher in patients with cancer than in control patients without cancer (P = 0.008, P < 0.01 and P < 0.01 respectively). The most common stroke etiologies were atherosclerosis of large arteries and stroke of undetermined cause in a cancerous group of patients. Cancer patients were accompanied by significant higher mortality rate (P = 0.005), and more disability as determined by mRS (P < 0.005) ConclusionsPathophysiology and mechanism of ischemic stroke in cancerous disease patients were due to different risk factors, biomarkers of stroke, and subtypes in comparison with non- cancerous cases.

MicroRNA-421-3p prevents inflammatory response in cerebral ischemia/reperfusion injury through targeting m6A Reader YTHDF1 to inhibit p65 mRNA translation

ObjectiveIschemic stroke is one of the leading causes of death globally, and inflammation is considered as a vital contributor to the pathophysiology of ischemic stroke. Recently, microRNA-421-3p-derived macrophages is found to promote motor function recovery in spinal cord injury. Here, we explored whether microRNA-421-3p is involved in inflammation responses during cerebral ischemia/reperfusion (I/R) injury and its molecular mechanism. MethodsAn in vivo experimental animal model of intraluminal middle cerebral artery occlusion/reperfusion (MCAO/R) and in vitro model of microglial subjected to oxygen-glucose deprivation and reoxygenation (OGD/R) were used. The effects of microRNA-421-3p on cerebral I/R injury and its underlying mechanism were detected by quantitative real-time PCR, western blotting, immunofluorescence staining, RNA immunoprecipitation, flow cytometry, luciferase reporter assay, and bioinformatics analysis. ResultsWe find that microRNA-421-3p is significantly decreased in cerebral I/R injury in vitro and in vivo. Furthermore, overexpression of microRNA-421-3p evidently suppresses pro-inflammatory factor expressions and inhibits NF-κB p65 protein expression and nuclear translocation in BV2 microglia cells treated with OGD/R. However, microRNA-421-3p neither promotes p65 mRNA expression, nor affects p65 mRNA or protein stability. Moreover, we find the m6A ‘reader’ protein YTH domain family protein 1 (YTHDF1) is the specific target of microRNA-421-3p, and YTHDF1 specifically binds to the m6a site of p65 mRNA to promote its translation. ConclusionmicroRNA-421-3p prevents inflammatory response in cerebral ischemia/reperfusion injury through targeting YTHDF1 to inhibit p65 mRNA translation. These findings provide novel insights into understanding the molecular pathogenesis of cerebral I/R injury.

Microglia-associated neuroinflammation is a potential therapeutic target for ischemic stroke.

Microglia-associated neuroinflammation plays an important role in the pathophysiology of ischemic stroke. Microglial activation and polarization, and the inflammatory response mediated by these cells play important roles in the development, progression and outcome of brain injury after ischemic stroke. Currently, there is no effective strategy for treating ischemic stroke in clinical practice. Therefore, it is clinically important to study the role and regulation of microglia in stroke. In this review, we discuss the involvement of microglia in the neuroinflammatory process in ischemic stroke, with the aim of providing a better understanding of the relationship between ischemic stroke and microglia.

The role of peptidase neurolysin in neuroprotection and neural repair after stroke.

Current experimental stroke research has evolved to focus on detailed understanding of the brain’s self-protective and restorative mechanisms, and harness this knowledge for development of new therapies. In this context, the role of peptidases and neuropeptides is of growing interest. In this focused review, peptidase neurolysin (Nln) and its extracellular peptide substrates are briefly discussed in relation to pathophysiology of ischemic stroke. Upregulation of Nln following stroke is viewed as a compensatory cerebroprotective mechanism in the acute phase of stroke, because the main neuropeptides inactivated by Nln are neuro/cerebrotoxic (bradykinin, substance P, neurotensin, angiotensin II, hemopressin), whereas the peptides generated by Nln are neuro/cerebroprotective (angiotensin-(1–7), Leu-/Met-enkephalins). This notion is confirmed by experimental studies documenting aggravation of stroke outcomes in mice after inhibition of Nln following stroke, and dramatic improvement of stroke outcomes in mice overexpressing Nln in the brain. The role of Nln in the (sub)chronic phase of stroke is less clear and it is likely, that this peptidase does not have a major role in neural repair mechanisms. This is because, the substrates of Nln are less uniform in modulating neurorestorative mechanisms in one direction, some appearing to have neural repair enhancing/stimulating potential, whereas others doing the opposite. Future studies focusing on the role of Nln in pathophysiology of stroke should determine its potential as a cerebroprotective target for stroke therapy, because its unique ability to modulate multiple neuropeptide systems critically involved in brain injury mechanisms is likely advantageous over modulation of one pathogenic pathway for stroke pharmacotherapy.

Inhibition of cyclooxygenase-1 does not reduce mortality in post-ischemic stroke rats

BackgroundIschemic stroke is one of the leading causes of mortality and morbidity. The currently available non-invasive therapeutic options are not sufficiently efficacious. Post-ischemic brain is characterized by a prominent inflammatory response. Little is known about the involvement of cyclooxygenase (COX)-1 in the pathophysiology of ischemic stroke. ObjectiveThis study was undertaken to examine the effects of a highly selective COX-1 inhibitor – mofezolac – on clinical outcomes and brain inflammatory markers in post-stroke rats. MethodsStroke was induced by subjecting rats to permanent middle cerebral artery occlusion (MCAO). Control rats underwent a sham surgery. Rats were treated with mofezolac (50 mg/kg, intraperitoneally [ip]) once daily for 14 days. Control animals were treated with vehicle. Body temperature (BT), neurological score (NS) and cumulative mortality were monitored at different time points. At the end of the experiment, rats were euthanized and three brain regions (hypothalamus, hippocampus and frontal cortex) were extracted. Levels of interleukin (IL)-6, prostaglandin (PG)E2 and tumor necrosis factor (TNF)-α in these brain regions were determined by ELISA kits. ResultsBT, NS and cumulative mortality were all significantly higher in post-MCAO rats than in sham-operated rats, irrespective of the treatment given. BT, NS and mortality rate did not differ significantly between mofezolac-treated and vehicle-treated sham-operated animals. BT was significantly lower in mofezolac-treated as compared to vehicle-treated post-MCAO rats. Mofezolac did not significantly alter NS in post-MCAO rats at any time-point. Cumulative 14-day mortality was non-significantly higher in mofezolac-treated as compared to vehicle-treated post-MCAO rats (48 % vs. 21 %, respectively; P = 0.184). Mostly, IL-6 and TNF-α levels did not differ between post-MCAO and sham-operated rats and were not affected by mofezolac treatment. In contrast, mofezolac significantly decreased PGE2 levels in post-MCAO rats’ brains. ConclusionOverall, these results suggest that chronic treatment with the selective COX-1 inhibitor mofezolac did not reduce morbidity or mortality in post-stroke rats.

Ponatinib-induced ischemic stroke in larval zebrafish for drug screening

Conventional mammalian ischemic stroke models for drug screening are technically challenging, laborious and time-consuming. In this study, using Ponatinib as an inducer, we developed and characterized a zebrafish ischemic stroke model. This zebrafish ischemic stroke had the cerebral vascular endothelial injury, thrombosis, reduced blood flow, inflammation and apoptosis as well as the reduced motility. The zebrafish ischemic stroke model was validated with 6 known human therapeutic drugs of ischemic stroke (Aspirin, Clopidogrel, Naoxintong capsules, Edaravone, Xingnaojing injection, Shuxuening injection). The mRNA levels of the neovascularization-related gene (vegfaa) and vascular endothelial growth factor receptor gene (VEGFR), neurodevelopment related genes (mbp and α1-tubulin), brain-derived neurotrophic factor (BDNF) and glial cell derived neurotrophic factor (GDNF) were significantly downregulated; whereas apoptosis-related genes (caspase-3, caspase-7, caspase-9 and bax/bcl-2), and inflammatory factor genes (IL-1β, IL-6, IL-10, TNF-α and NF-κB) were remarkably upregulated in the model. These results suggest that the pathophysiology of Ponatinib-induced zebrafish ischemic stroke is similar to that of human ischemic stroke patients and this whole animal model could be used to study the complex cellular and molecular pathogenesis of ischemic stroke and to rapidly identify therapeutic agents.

Changes in the cerebrospinal fluid lipid profile following subarachnoid hemorrhage in a closed cranium model: Correlations to cerebral vasospasm, neuronal cell death and Interleukin-6 synthesis. A pilot study

BackgroundPhospholipids and sphingolipids are cell membrane components, that participate in signaling events and regulate a wide variety of vital cellular processes. Sphingolipids are involved in ischemic stroke pathophysiology. Throughout cleavage of membrane sphingomyelin by sphingomyelinase in stroke patients, it results in increased Ceramide (Cer) levels in brain tissue. Different studies showed the evidence that sphingomyelinase with Cer production induces expression of interleukin (IL)-6 and have vasoconstrictive proprieties. With this study, we intend to evaluate cerebrospinal fluid (CSF) lipid profile changes in a rabbit closed cranium subarachnoid hemorrhage (SAH) model. MethodsA total of 14 New Zealand white rabbits were randomly allocated either to SAH or sham group. In the first group SAH was induced by extracranial-intracranial shunting from the subclavian artery into the cisterna magna. Intracranial pressure (ICP) and arterial blood pressure were continuously monitored. Digital subtraction angiography of the basilar artery, CSF and blood samples were performed at day 0 pre SAH and on day 3 post SAH. The amount of IL-6 and various lipids in CSF were quantified using ELISA and Liquid Chromatography-Mass Spectrometry respectively. Cell death was detected in bilateral basal cortex, hippocampus (CA1 and CA3) using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). ResultsSAH Induction led to acute increase of ICP and increased delayed cerebral vasospasm (DCVS). At follow up CSF IL-6 levels showed a significant increase compared to baseline. Between baseline and follow up there were no significant differences in any of the measured CSF Lipids irrespective of subgroups. No relevant correlation was found between IL-6 and any of the sphingolipids. We found a correlation between baseline and follow up for the phospholipids phosphatidylethanolamine and phosphatidylcholine. ConclusionsNeuronal apoptosis, DCVS and IL-6 seems not to be related to changes in CSF lipid profiles except for PEA and PC in a rabbit closed cranium SAH model.

Combined polymorphisms in genes encoding the inflammasome components NLRP3 and CARD8 confer risk of ischemic stroke in men

IntroductionPrevious studies have reported the involvement of nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasome in the inflammatory activation and pathophysiology of Ischemic Stroke (IS). Variations in genes encoding the constituent proteins of NLRP3 inflammasome can alter the risk of IS. ObjectiveWe investigated the role of the NLRP3 inflammasome in the pathogenesis of IS by establishing associations between combined polymorphisms of caspase recruitment domain-containing protein 8 (CARD8) rs2043211 and NLRP3 rs10754558 and the susceptibility to IS in a Chinese population. MethodsSingle nucleotide polymorphisms (SNPs) in CARD8 rs2043211 and NLRP3 rs10754558 were analyzed using TaqMan SNP genotyping assays in patients with IS (n=234) and healthy controls (n=115). Logistic regression analysis was carried out to evaluate potential interactions between CARD8 and NLRP3. ResultsCompared with healthy controls, there were no significant differences in the minor allele frequency (MAF) and the genotype frequency of NLRP3 rs10754558 or CARD8 rs2043211 in patients with IS(P>0.05). After stratification by gender, there was an increased risk for IS in men carrying heterozygous CARD8 rs2043211 when a co-dominant genetic model was applied (P=0.021, OR=3.83[1.22–12.03]). Logistic regression analysis indicated that men carrying both CARD8 rs2043211 AT and NLRP3 rs10754558 CG had a significantly higher risk of IS (P=0.046, OR=7.116[1.033–49.044]). ConclusionsNucleotide variations in the genes encoding NLRP3 inflammasome proteins may be important to IS, and men carrying CARD8 rs2043211 and NLRP3 rs10754558, both heterozygous, confer a higher risk of IS.

Is there Still a Time Window in the Treatment of Acute Stroke?

It has become evident that strict time-based criteria are not optimal in selecting patients for acute stroke intervention, leaving the majority of patients untreated due to missing universal time-based criteria. We discuss the pathophysiologic basis for a shift of focus from time to the imaging evidence of salvageable tissue, as well as clinical and imaging tools. There is strong evidence for the benefit of thrombectomy in patients with a sustained salvageable tissue presenting within 24 h. Although evidence of benefit is limited in patients presenting longer than 24 h, those patients will have a poor functional outcome if untreated. MRI-based approaches to choose patients for thrombolytic therapy later than 4.5 h are relatively safe and modestly effective. Defining a patient-based therapeutic window to replace strict time windows and therefore refining patient exclusion and inclusion criteria is possible through understanding pathophysiology of acute ischemic stroke in individual patients.

Hypothesis and Theory: A Pathophysiological Concept of Stroke-Induced Acute Phase Response and Increased Intestinal Permeability Leading to Secondary Brain Damage.

Gut integrity impairment leading to increased intestinal permeability (IP) is hypothesized to be a trigger of critically illness. Approximately 15–20% of human ischemic stroke (IS) victims require intensive care, including patients with impaired level of consciousness or a high risk for developing life-threatening cerebral edema. Local and systemic inflammatory reactions are a major component of the IS pathophysiology and can significantly aggravate brain tissue damage. Intracerebral inflammatory processes following IS have been well studied. Until now, less is known about systemic inflammatory responses and IS consequences apart from a frequently observed post-IS immunosuppression. Here, we provide a hypothesis of a crosstalk between systemic acute phase response (APR), IP and potential secondary brain damage during acute and subacute IS stages supported by preliminary experimental data. Alterations of the acute phase proteins (APPs) C-reactive protein and lipopolysaccharide-binding protein and serum level changes of antibodies directed against Escherichia coli-cell extract antigen (IgA-, IgM-, and IgG-anti-E. coli) were investigated at 1, 2, and 7 days following IS in ten male sheep. We found an increase of both APPs as well as a decrease of all anti-E. coli antibodies within 48 h following IS. This may indicate an early systemic APR and increased IP, and underlines the importance of the increasingly recognized gut-brain axis and of intestinal antigen release for systemic immune responses in acute and subacute stroke stages.

Predictive value of inflammatory markers for functional outcomes in patients with ischemic stroke

Background: Inflammatory processes have been proposed in the pathophysiology of ischemic stroke. The present study was designed to evaluate the relationship between tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), IL 1 beta (IL-1β), and high sensitivity C-reactive protein (hsCRP) with the prognosis and functional outcome in patients with less severe ischemic stroke. Methods: We measured the level of IL-1β, IL-6, hsCRP, and TNF-α on days 1 and 5 after stroke onset by enzyme-linked immunosorbent assay (ELISA). The infarct volume was assessed using Alberta Stroke Program Early CT Score (ASPECTS) and posterior circulation ASPECTS (pcASPECTS) score in brain computed tomography (CT) scan and magnetic resonance imaging (MRI). The severity of stroke was assessed by applying the National Institutes of Health Stroke Scale (NIHSS) and Modified Rankin Scale (MRS) in 24 hours on day 5 and after 3 months from stroke onset. Good outcome was defined as the third month MRS ≤ 2. The association of inflammatory markers and the course of stroke symptoms over time was examined. Results: Forty-four first-ever stroke patients without concurrent inflammatory diseases with a mean age of 65 years were included. The mean NIHSS and MRS in admission time were 6.5 ± 3.5 and 3.07, respectively. The day 1 and the day 5 levels of IL-1β, IL-6, hsCRP, and TNF-α were not significantly different in good and poor outcome groups (all P-values > 0.05). In addition, they were not significantly associated with the ASPECTS, pcASPECTS, and changes of NIHSS and MRS over time. Conclusion: The levels of hsCRP, IL-1β, IL-6, and TNF-α are not reliable predictors of functional outcomes in patients with less severe acute ischemic stroke (AIS).

Bacterial Peptidoglycan and Leukocyte Reactivity in the Brain Following Ischaemic Stroke

It has recently been reported that bacteria found in the brain of neurodegenerative diseases, such as Alzheimer’s and amyotrophic lateral sclerosis, may cause neuroinflammation. Whilst infiltrating immune cells into brain are a key contributor to the pathophysiology of ischaemic stroke, whether or not this is due to the presence of bacteria within the brain remains to be determined. Therefore, the aim of this study was to establish whether peptidoglycan positive bacteria located within the ischaemic hemisphere post‐stroke attract infiltrating immune cells. To test this aim, C57BL6 male mice (8–12 weeks old) were subjected to either photothrombotic stroke (n=16), 0.5 h middle cerebral artery occlusion (MCAO, n=12) or sham surgery (n=12). Functional tests assessing motor function were conducted pre‐surgery, 24 h and/or 72 h post‐surgery. Infarct volume was assessed at 24 or 72 h post‐stroke via thionin staining and infiltrating immune cells within the brain were identified by immunofluorescence. Photothrombosis or MCAO caused significant functional impairment, as determined by the hanging wire and cylinder tests, compared to sham (P&lt;0.05). Photothrombotic stroke caused cortical infarct damage whereas MCAO induced hypothalamic, thalamic, hippocampal and cortical infarct damage. Peptidoglycan immunoreactivity was observed within the infarct core of both ischaemic stroke models at 24 and 72 h post‐surgery. Whilst infiltrating myeloperoxidase‐positive neutrophils were located in close proximity with peptidoglycan‐positive cells at 24 h post‐stroke, F4/80‐positive macrophages were co‐localised with peptidoglycan‐positive cells at 72 h post‐stroke. Collectively, these data suggest that bacteria located in the infarct core following cerebral ischaemia may trigger an immune response, and thus could be a therapeutic target for stroke patients.

Collateral augmentation treatment with a combination of acetazolamide and head-down tilt in a rat ischemic stroke model

Cerebral collaterals is crucially important in the pathophysiology of acute ischemic stroke and associated with outcome after reperfusion therapy. We explored the effectiveness of collateral augmentation treatment with a combination of acetazolamide (ACZ) and head-down tilt (HDT) in the transient middle cerebral artery occlusion (MCAO) rat model. Transient MCAO was induced in all animals for 1.5 h, followed by reperfusion for 22.5 h. Seventy-two male Wistar rats were divided into four treatment groups: control, ACZ, HDT, and combination. Twenty sham rats, which underwent surgery, were randomly allocated to these groups. Twenty-four hours after MCAO or sham surgery, we measured the infarction volume, brain edema (aquaporin-4 [AQP4], and brain water content), and neurological deficits (Garcia and Longa tests). Collateral augmentation treatments were associated with reduced infarction volume, less brain edema, and better neurological outcomes compared with untreated animals. More specifically, ACZ and HDT treatments resulted in small infarction volumes, and HDT was associated with a low AQP4 expression and improved neurological score, while the combination of ACZ and HDT improved neurological scores and reduced brain water content. This study shows that collateral augmentation treatments are associated with a better stroke prognosis compared with untreated animals after transient MCAO. The combination of ACZ and HDT seems to have some synergistic effect, but was not proven to be superior to HDT treatment alone.

Abstract WP256: Atrial Fibrillation Predicting Factors in Transient and Minor Stroke Patients

Introduction and Purpose: Our aim was to review the characteristics of transient ischemic attack (TIA) and minor ischemic stroke patients monitored for atrial fibrillation (AF) epidoses detection within the first 4weeks after stroke to assess AF predictors. Materials and Methods: TIA and minor ischemic stroke patients (nihss≤ 5) were selected from CRYPTO-AF database. CRYPTO-AF is a prospective multicentre registry of patients with cryptogenic stroke older of 55 year-old. Monitoring started within the first 72 hours from stroke symptoms onset and was prolonged for 4 weeks. Clinical, cardiographic and blood test parameters of patients included were reviewed. Fisher exact and Mann Whitney tests were used to analyze categorical and continuous data. Results: In our cohort of 152 transient and minor ischemic stroke patients, 55.9% were men, mean age 73.18±10.24 and median NIHSS score was 2.31(0-5). A total of 30 patients (20.3%) were diagnosed with AF in the first month of monitoring, 6 patients (5.7%) within the first 3 days, 14 patients (13.3%) between 3 days and to 2 weeks of monitoring, and 14 partientes (12.4%) between the second and the fourth week. In these transient and minor ischemic stroke patients, age (p&lt; 0.031), left atrial volume index (p&lt; 0.023), the appearance of isolated extrasystoles during monitoring (p&lt; 0.021), Type B natriuretic peptide (p&lt; 0.011) and the longitudinal strain (p&lt; 0.019) appeared as independet precitors of AF. However in the multivariate analysis adjusted for the above variables, only left atrial strain (OR 0.89, 95% CI: 0.797-0.991, p&lt; 0.034) independently predicts AF detection. Conclusions: In our serie, only the left atrial strain appeared as a indepent predictor of AF. Given the known pathophysiology of TIA and minor ischemic stroke, the description of AF predictors would help to identify those patients who would benefit from completing a longer monitoring. More studies are needed to identify these predictors.

Pathophysiology of Ischemic Stroke: Role of Oxidative Stress

Pathophysiology of Ischemic Stroke: Role of Oxidative Stress