Brain Infarct Size Research Articles

Potential Anti-Thrombotic Effect without Accompanying Hemorrhage with Fostamatinib Use in Patients with Immune Thrombocytopenia

Potential Anti-Thrombotic Effect without Accompanying Hemorrhage with Fostamatinib Use in Patients with Immune Thrombocytopenia

Attenuating effect of α-pinene on neurobehavioural deficit, oxidative damage and inflammatory response following focal ischaemic stroke in rat.

Oxidative stress and inflammation have a critical role in the pathogenesis of ischaemic stroke. Alpha-pinene is a monoterpenoid molecule with anti-inflammatory and antioxidant properties. The nobility of the present study was to evaluate the neuroprotective effect of α-pinene in ischaemic stroke. Ischaemic stroke was induced by transient middle cerebral artery occlusion followed by 24h reperfusion in male Wistar rats. Alpha-pinene (25, 50 and 100mg/kg, i.p.) was administered in the beginning of reperfusion. Then, the neurobehavioural function, infarct volume, brain oedema, antioxidant enzyme activity and the concentration of malondialdehyde (MDA), nitric oxide (NO) and interleukin-6 (IL-6) were evaluated by different methods in the brain. Alpha-pinene (50 and 100mg/kg) elicited a significant decrease in the brain oedema and infarct size as well as an improvement in the neurobehavioural function. Besides, α-pinene (100mg/kg) restored the function of superoxide dismutase, catalase and glutathione peroxidase and reduced the concentration of MDA, NO and IL-6 in the hippocampus, cortex and striatum. It was ultimately attainted that α-pinene exerts neuroprotective effect in ischaemic stroke in rat through the restoration of antioxidant enzymes activity, attenuation of lipid peroxidation and reduction of inflammation in the ischaemic brains.

TMEM16A Inhibition Preserves Blood-Brain Barrier Integrity After Ischemic Stroke.

The inflammatory response plays a pivotal role in Blood–Brain Barrier (BBB) destruction following ischemic brain injury. Enhanced leukocyte adhesion to vascular endothelial cells is an essential event in the inflammatory process. TMEM16A, a newly discovered protein regulating calcium-activated chloride channels, is widely expressed in eukaryotes. Recent studies have suggested that upregulated expression of TMEM16A is associated with the occurrence and development of many diseases. However, the role of TMEM16A in regulating BBB integrity after ischemic stroke has not been fully investigated. In this study, we found that TMEM16A is mainly expressed in brain endothelial cells and upregulated after ischemic stroke in the mouse brain. Caccinh-A01, an TMEM16A inhibitor that reduced its upregulation, attenuated brain infarct size and neurological deficits after ischemic stroke. ICAM-1 and MPO expression and BBB permeability were decreased after TMEM16A inhibitor administration. In addition, TMEM16A silencing rescued oxygen-glucose deprivation/reoxygenation (OGD/R)-induced transendothelial permeability in vitro accompanied by decreased ICAM-1 expression and leukocyte adhesion. Furthermore, our mechanistic study showed that TMEM16A knockdown alleviated NF-κB activation and nuclear translocation, indicating that TMEM16A knockdown downregulated OGD/R-induced ICAM-1 expression in an NF-κB-dependent manner. Finally, NF-κB inhibitor treatment also alleviated OGD/ R-induced BBB permeability, confirming that activated NF-κB and increased ICAM-1 are essential factors involved in ischemia-induced BBB damage. Thus, our research provides a promising treatment strategy against BBB destruction after ischemic stroke, and TMEM16A may become a potential target for the treatment of ischemic stroke.

LncRNA SNHG6 functions as a ceRNA to regulate neuronal cell apoptosis by modulating miR-181c-5p/BIM signalling in ischaemic stroke.

Long non‐coding RNAs (lncRNAs) play important roles in the pathogenesis of brain and neurodegenerative disorders. As far as we know, the functions and potential mechanisms of small nucleolar RNA host gene 6 (SNHG6) in ischaemic stroke have not been explored. This study aimed to examine the functional role of SNHG6 in the ischaemic stroke. Middle cerebral artery occlusion (MCAO) in mice and the oxygen glucose deprivation (OGD)‐induced injury in neuronal cells were applied to mimic ischaemic stroke. TTC staining, quantitative real‐time PCR, cell apoptosis assay, caspase‐3 activity assay, Western blot, RNA immunoprecipitation and luciferase reporter assay were performed to evaluate the function and possible mechanisms of SNHG6 in the pathogenesis of ischaemic stroke. The results show that SNHG6 expression was significantly increased both OGD‐induced neuronal cells and MCAO model mice. In vitro results showed that inhibition of SNHG6 increased cell viability, inhibited cell apoptosis and caspase‐3 activity in OGD‐induced neuronal cells. Consistently, knockdown of SNHG6 reduced brain infarct size and improved neurological scores in the MCAO mice. Mechanistic study further revealed that SNHG6 functioned as a competing endogenous RNA (ceRNA) for miR‐181c‐5p, which in turn repressed its downstream target of Bcl‐2 interacting mediator of cell death (BIM) and inhibiting cell apoptosis. This study revealed a novel function of SNHG6 in the modulating neuronal apoptosis in the ischaemic stroke model, and the role of SNHG6 in the regulating of neuronal apoptosis was at least partly via targeting miR‐181c‐5p/BIM signalling pathway.

Repression of the Glucocorticoid Receptor Increases Hypoxic-Ischemic Brain Injury in the Male Neonatal Rat

Hypoxic-ischemic encephalopathy (HIE) resulting from asphyxia is the most common cause of neonatal brain damage and results in significant neurological sequelae, including cerebral palsy. The current therapeutic interventions are extremely limited in improving neonatal outcomes. The present study tests the hypothesis that the suppression of endogenous glucocorticoid receptors (GRs) in the brain increases hypoxic-ischemic (HI) induced neonatal brain injury and worsens neurobehavioral outcomes through the promotion of increased inflammation. A mild HI treatment of P9 rat pups with ligation of the right common carotid artery followed by the treatment of 8% O2 for 60 min produced more significant brain injury with larger infarct size in female than male pups. Intracerebroventricular injection of GR siRNAs significantly reduced GR protein and mRNA abundance in the neonatal brain. Knockdown of endogenous brain GRs significantly increased brain infarct size after HI injury in male, but not female, rat pups. Moreover, GR repression resulted in a significant increase in inflammatory cytokines TNF-α and IL-10 at 6 h after HI injury in male pups. Male pups treated with GR siRNAs showed a significantly worsened reflex response and exhibited significant gait disturbances. The present study demonstrates that endogenous brain GRs play an important role in protecting the neonatal brain from HI induced injury in male pups, and suggests a potential role of glucocorticoids in sex differential treatment of HIE in the neonate.

TRPV1 mediates astrocyte activation and interleukin-1\u03b2 release induced by hypoxic ischemia (HI)

BackgroundHypoxic-ischemic encephalopathy (HIE) is a serious birth complication with high incidence in both advanced and developing countries. Children surviving from HIE often have severe long-term sequela including cerebral palsy, epilepsy, and cognitive disabilities. The severity of HIE in infants is tightly associated with increased IL-1β expression and astrocyte activation which was regulated by transient receptor potential vanilloid 1 (TRPV1), a non-selective cation channel in the TRP family.MethodsNeonatal hypoxic ischemia (HI) and oxygen-glucose deprivation (OGD) were used to simulate HIE in vivo and in vitro. Primarily cultured astrocytes were used for investigating the expression of glial fibrillary acidic protein (GFAP), IL-1β, Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), and activation of the nucleotide-binding, oligomerization domain (NOD)-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome by using Western blot, q-PCR, and immunofluorescence. Brain atrophy, infarct size, and neurobehavioral disorders were evaluated by Nissl staining, 2,3,5-triphenyltetrazolium chloride monohydrate (TTC) staining and neurobehavioral tests (geotaxis reflex, cliff aversion reaction, and grip test) individually.ResultsAstrocytes were overactivated after neonatal HI and OGD challenge. The number of activated astrocytes, the expression level of IL-1β, brain atrophy, and shrinking infarct size were all downregulated in TRPV1 KO mice. TRPV1 deficiency in astrocytes attenuated the expression of GFAP and IL-1β by reducing phosphorylation of JAK2 and STAT3. Meanwhile, IL-1β release was significantly reduced in TRPV1 deficiency astrocytes by inhibiting activation of NLRP3 inflammasome. Additionally, neonatal HI-induced neurobehavioral disorders were significantly improved in the TRPV1 KO mice.ConclusionsTRPV1 promotes activation of astrocytes and release of astrocyte-derived IL-1β mainly via JAK2-STAT3 signaling and activation of the NLRP3 inflammasome. Our findings provide mechanistic insights into TRPV1-mediated brain damage and neurobehavioral disorders caused by neonatal HI and potentially identify astrocytic TRPV1 as a novel therapeutic target for treating HIE in the subacute stages (24 h).

Carotid artery disease in post-stroke survivors and effects of enriched environment on stroke pathology in a mouse model of carotid artery stenosis.

Carotid artery disease (CAD) is an important risk factor for stroke. We first evaluated CAD and stroke pathology in elderly post-stroke survivors. To simulate CAD, we assessed long-term consequences of bilateral common carotid artery stenosis (BCAS) in mice and exposed them to environmental enrichment (EE). Histopathological methods were used to determine degrees of CAD (% area stenosis), brain infarct types, sizes and distribution in post-stroke survivors and BCAS mice. Adult male C57BL/6J mice after BCAS or sham surgery were randomly assigned to standard housing (Std) or limited (3h) or full-time (Full) exposure to EE per day for 12weeks. High frequencies of moderate carotid artery stenosis (51-75%) were evident in post-stroke survivors whereas those with severe CAD (>75% stenosis) exhibited greater numbers of cortical rather than subcortical infarcts and, were at higher risk of developing dementia. BCAS in mice reduced cerebral blood flow by 52% (P<0.01) and thickened carotid artery walls, regardless of EE duration. Remarkably, the total and cortical infarcts declined by >50% in BCAS mice exposed to EE compared with BCAS-Std (P<0.01). Frontal lobe and cortical strokes were associated with worsening working memory tested in a radial maze paradigm. Proteomic analysis revealed EE, both BCAS-3h and BCAS-Full attenuated coagulation cascade factors including fibrinogen and von Willebrand factor, markers of blood-brain barrier damage. Small cortical and subcortical infarcts were evident in both post-stroke survivors with CAD and BCAS mice. Experimental evidence suggested that moderate exposure to EE is sufficient to reduce subsequent stroke lesions.

Sodium Dichloroacetate Stimulates Angiogenesis by Improving Endothelial Precursor Cell Function in an AKT/GSK-3β/Nrf2 Dependent Pathway in Vascular Dementia Rats.

Sodium dichloroacetate (DCA) is a mitochondrial pyruvate dehydrogenase kinase inhibitor, and has been shown to display vasoprotective effects in chronic ischemic stroke. The purpose of this study was to evaluate the therapeutic effect of DCA on vascular dementia (VD) and endothelial progenitor cell (EPC)-mediated angiogenesis. After cerebral ischemia-reperfusion in rats, DCA was administered continuously for 21 days; following which, histological analysis, and cognitive functional tests were conducted. Rat bone marrow-derived EPCs were isolated, their function and quantity were measured, and the effects of long-term administration of DCA on EPCs in a rat model of VD was studied. We found that long-term DCA administration improved cognitive function in VD rats, reduced brain infarct size and brain atrophy, increased VEGF and bFGF levels in vivo, promoted angiogenesis in damaged areas, and significantly improved EPC function in VD rats. Compared with the VD group, AKT, Nrf2, eNOS expression, and intracellular NO levels were elevated in EPCs of DCA-treated VD rats. In addition, GSK3β and intracellular ROS levels were decreased. Simultaneously, it was found that DCA directly acted on EPCs, and improved EPC functional behavior. Taken together, these findings suggested that long-term DCA administration improved cognitive function in a rat model of VD, and did so in part, by improving EPC function. Observations suggest that prolonged DCA administration might be beneficial in treating VD.

Atractylenolide III ameliorates cerebral ischemic injury and neuroinflammation associated with inhibiting JAK2/STAT3/Drp1-dependent mitochondrial fission in microglia

BackgroundInflammation is a major contributor to stroke pathology, making it a promising strategy for intervention. Microglia, the resident macrophages in the brain, play essential roles in both the generation and resolution of neuroinflammation. In particular, mitochondrial homeostasis is critical for microglial function and its dysregulation is involved in the pathogenesis of ischemic stroke. Atractylenolide III (A III), a sesquiterpene lactone found in Atractylodes macrocephala Koidz, has been shown to have an inhibitory effect on inflammation. However, its effect specifically on neuroinflammation and microglial mitochondrial homeostasis following stroke remains elusive. HypothesisWe hypothesized that A III protects against brain ischemia through inhibition of neuroinflammation mediated by JAK2/STAT3/Drp1-dependent mitochondrial fission. MethodsThe neuroprotective and anti-neuroinflammatory effects of A III were investigated in vivo in mice with transient occlusion to the middle cerebral artery (MCAO) and in vitro in oxygen glucose deprivation-reoxygenation (OGDR)-stimulated primary microglia from mice. ResultsA III and AG490, an inhibitor of JAK2, treatment reduced brain infarct size, restored cerebral blood flow (CBF), ameliorated brain edema and improved neurological deficits in MCAO mice. Furthermore, A III and AG490 inhibited mRNA and protein expressions of proinflammatory (IL-1β, TNF-α, and IL-6) and anti-inflammatory cytokines in both MCAO mice and OGDR-stimulated primary microglia. The JAK2/STAT3 pathway was effectively suppressed by A III, similar to the effect of AG490 treatment. In addition, A III and AG490 treatments significantly decreased Drp1 phosphorylation, translocation and mitochondrial fission in primary microglia stimulated with OGDR for 24 h. ConclusionOur study demonstrated that A III was able to reduce complications associated with ischemia through inhibiting neuroinflammation, which was mediated in part by JAK2/STAT3-dependent mitochondrial fission in microglia.

Acid-Sensing Ion Channel 1a Modulates NMDA Receptor Function Through Targeting NR1/NR2A/NR2B Triheteromeric Receptors

The over-activation of N-methyl-D-aspartate receptors (NMDARs) is the main cause of neuronal death in brain ischemia. Both the NMDAR and the Acid-sensing ion channel 1a (ASIC1a) are present in the postsynaptic membrane of the central nervous system (CNS) and participate in physiological and pathological processes. However, the specific role played by ASIC1a in these processes remains elusive. We hypothesize that NMDARs are the primary mediators of normal synaptic transmission and excitatory neuronal death, while ASIC1a plays a modulatory role in facilitating NMDAR function. Using various experimental approaches including patch-clamp recordings on hippocampal slices and CHO cells, primary cultures of hippocampal neurons, calcium imaging, Western blot, cDNA transfection studies, and transient middle cerebral artery occlusion (tMCAO) mouse models, we demonstrate that stimulation of ASIC1a facilitates NMDAR function and inhibition of ASIC1a suppresses NMDAR over-activation. One of our key findings is that activation of ASIC1a selectively facilitates the NR1/NR2A/NR2B triheteromeric subtype of NMDAR currents. In accordance, inhibition of ASIC1a profoundly reduced the NMDAR-mediated EPSCs in older mouse brains, which are known to express much higher levels of triheteromeric NMDARs than younger brains. Furthermore, brain infarct sizes were reduced by a greater degree in older mice compared to younger ones when ASIC1a activity was suppressed. These data suggest that ASIC1a activity selectively enhances the function of triheteromeric NMDARs and exacerbates ischemic neuronal death especially in older animal brains. We propose ASIC1a as a novel therapeutic target for preventing and reducing the detrimental effect of brain ischemia in humans.

Expression of S100B Protein in Ischemia/Reperfusion-Induced Brain Injury After Cyclosporine Therapy: A Biochemical Serum Marker with Prognostic Value?

BackgroundAccumulating evidence has indicated that S100B protein may be involved in the pathophysiology of ischemia-reperfusion brain injury. Cyclosporine has been shown to have neuroprotective functions. This study investigated the effect of cyclosporine on S100B serum levels and the severity of brain tissue damage in a rat model of cerebral ischemia-reperfusion (I/R).Material/MethodsTwelve-week-old Wistar male rats were randomly divided into Control I/R and Cyclosporine I/R groups (n=10 each). Cyclosporine was given orally by gavage for 5 days prior to cerebral I/R, at a total volume of 15 mg/kg/day. The Control group received an equal volume of saline. Body weight was measured and all animals were subjected to 60-min focal ischemia by filament occlusion of the middle cerebral artery. ELISA was used to assess the concentrations of serum S100B and development of brain infarct size and neurological outcomes were determined at 2 and 24 h after occlusion withdrawal.ResultsCyclosporine improved the neurological deficit score and decreased the cerebral infarct size and body weight. S100B serum levels were significantly elevated in Cyclosporine-treated rats compared with untreated Control rats during the reperfusion phase. Total infarct size was positively associated with S100B serum levels in the Control I/R group, but no significant correlation was observed in the Cyclosporine I/R group.ConclusionsCyclosporine seems to affect both ischemia-reperfusion brain tissue damage and S100B protein serum levels. S100B serum level appears to be a state marker for the severity of the cerebral ischemia-reperfusion, rather than a trait marker for Cyclosporine responsiveness.

Delayed treatment of \u03b15 GABAA receptor inverse agonist improves functional recovery by enhancing neurogenesis after cerebral ischemia-reperfusion injury in rat MCAO model

Development of effective therapeutics and treatment strategy to promote recovery after cerebral ischemia-reperfusion injury necessitates further understandings of the complex pathophysiology of ischemic stroke. Given that α5-GABAAR inhibition has been shown to be involved in functional recovery after stroke, the present study was designed to evaluate the effects of treatment timing of α5 GABAAR inhibition on post-middle cerebral artery occlusion (MCAO) functional recovery. To this end, we examined the effects of L655,708 (α5 GABAAR inverse agonist) treatment at 3 or 7 days post-ischemia on apoptosis and neurogenesis in the peri-infarct region, brain infarction size, as well as modified neurological severity score (mNSS) and rotarod test time in rats. Consistent with previous reports, we found that when the treatment of L655,708 was initiated at post-MCAO day 3, it did not alter the functional recovery in rats. However, when the treatment of L655,708 was initiated at post-MCAO day 7, it demonstrated beneficial effects on functional recovery in rats. Interestingly, this phenomenon was not associated with altered brain infarction size nor with changes in brain cell apoptosis. However, we found that delayed treatment of L655,708 at post-MCAO day 7 significantly increased neurogenesis in peri-infarct zone in rats. These results suggested that removing α5 GABAAR-mediated tonic inhibition after cerebral ischemia-reperfusion injury may be an effective therapeutic strategy for promoting functional recovery from stroke.

Gastrodin pretreatment alleviates rat brain injury caused by cerebral ischemic-reperfusion

Brain damage, including blood-brain barrier (BBB) dysfunction, neurological behavior deficit, cerebral infarction and inflammation, is commonly caused by ischemic-reperfusion (I/R) injury. Prevention of the above biological process defects is considered beneficial for patient recovery after I/R injury. This study was aimed to assess the neuroprotective effect of Gastrodin (GAS), an herbal agent, in experimentally induced cerebral ischemia. Sprague-Dawley adult rats were randomly divided into six groups: Sham-operated control group (Sham), middle cerebral artery occlusion (MCAO) group, GAS (50, 100, and 200 mg/kg) pretreatment + MCAO groups (GAS) and Nimodipine (NIM) + MCAO, namely, the NIM group. Additionally, an OGD/R model using BV-2 microglia was established in vitro to simulate I/R injury. We showed here that the neurological scores of rats in the GAS groups were significantly improved compared with the MCAO group. Moreover, the area of cerebral infarction in the GAS pretreatment groups and the NIM group was significantly reduced. Furthermore, Evans blue leakage volume was significantly reduced with GAS pretreatment notably at dose 100 mg/kg. Expression of matrix metalloproteinase 2 (MMP2) and MMP9 in GAS groups was markedly decreased when compared with MCAO group. In BV-2 microglia exposed to OGD/R given GAS pretreatment, MMP2 and MMP9 positive cells were reduced in numbers. The present results have shown that GAS pretreatment significantly compensated for neurological behavior defects in rats with I/R-induced injury, reduced brain infarction size, reversed BBB impairment, and attenuated inflammation. It is suggested that pretreatment with GAS before surgery is beneficial during recovery from I/R injury.

Abstract TP573: Nrf2 Activation With Sulforaphane Reduces Post-Stroke Cognitive Impairment in Mice

Introduction: Post-stroke dementia is common in stroke patients and oxidative stress may contributes to its pathogenesis. Nuclear factor erythroid 2 related factor (Nrf2) is a master transcription factor regulating the expression of a series of anti-oxidative enzymes. Sulforaphane (Sfn) is a dietary Nrf2 activator rich in cruciferous vegetables. This study aims to test our hypothesis that Sfn treatment reduces white matter injury and cognitive impairment after ischemic stroke. Methods: Adult male and female wildtype and Nrf2 knockout mice were randomly and blindly assigned into sham, vehicle, and Sfn-treatment groups (n=8-10). Stroke was induced in mice by direct coagulation of the left distal middle cerebral artery and permanent ligation of left common carotid artery occlusion. Sfn in PBS was administered by intraperitoneal injection (20 mg/kg) starting after the surgery and subsequently every other day for 5 weeks. Sensorimotor deficits were assessed using Rota-rod and foot fault tests 3-35 d and cognitive impairment were determined using Morris water maze test 29-34 d after surgery. Brain tissue loss was assessed at 35 d after surgery. In vitro, primary neuronal cultures were treated with vehicle or Sfn (1.5 μM) and chronic hypoxia/ischemia was then induced by incubation with cobalt chloride (250 μM) for 48 h. Neuronal viability was assessed with MTT assay. Results: Wildtype mice exhibited significantly sensorimotor deficits and long-term cognitive impairment after stroke. Sfn treatment alleviated these sensorimotor deficits, long-term cognitive impairment, and brain infarct size in wildtype mice. Nrf2 knockout mice also exhibited significantly sensorimotor deficits and long-term cognitive impairment after stroke; however, Sfn treatment didn’t affect these sensorimotor. In cultures, neuronal survival rate in Sfn group was significantly higher compared with vehicle group. Nrf2 knockdown with Nrf2-shRNA abolished the protective effects of Sfn. Conclusion: Sfn treatment reduces cognitive impairment after stroke in mice in a Nrf2 depended manner. Nrf2 may be a promising target to reduce post-stroke cognitive impairment.

Nerve growth factor alleviates cerebral infarction and neurologic deficits by regulating VEGF, SDF-1 and S100A12 expression through PI3K pathway

Stroke remains the leading cause of death and disability worldwide, which destroys the quality of patients’ lives and thus is becoming a heavy burden to the society. However, the current therapeutic approaches are far from satisfaction. The objective of this study is to elucidate the impact of nerve growth factor (NGF) on the brain damage induced by cerebral ischemia and its potential molecular mechanism. Middle cerebral artery occlusion (MCAO) rats were used as animal models and neurological functions were evaluated by modified Neurological Severity Score (NSS). Brain cell apoptosis was analyzed by TUNEL-positive staining while brain infarct size was determined according to 2% 2,3,5-triphenyltetrazolium chloride (TCC) staining volume. Rats receiving NGF demonstrated significantly alleviated brain damage, reflected by a substantial improvement in the neurobehavioral outcome, a decrease in brain cell apoptosis and shrinkage of brain infarct volume. Further analysis revealed a markedly elevated circulating vascular endothelial growth factor (VEGF) and stromal cell-derived factor 1 (SDF-1) levels as well as a significant downregulation of SA10012 expression in NGF treated group compared with the untreated group. Strikingly, the protective effect of NGF on cerebral ischemic injury was abolished in rats treated with both NGF and PI3K inhibitors, indicating that phosphoinositide-3-kinase (PI3K) signaling is essential for NGF function. In conclusion, NGF treatment might be a potential therapeutic approach against cerebral infarction by downregulating SA10012 expression and upregulating VEGF, SDF-1 in a PI3K signaling dependent manner.

BKCa channel is a molecular target of vitamin C to protect against ischemic brain stroke.

Epidemiological studies have demonstrated that vitamin C decreases the risk of stroke, which has generally been ascribed to its function as antioxidant and free radical scavenger. However, whether there is a defined molecular target for vitamin C on stroke is unknown. Utilizing middle cerebral artery occlusion (MCAO) in rats as a model for ischemic stroke, we demonstrated that long-term, low-dose administration of vitamin C prior to MCAO could exert significant neuroprotective effect on the brain damage. The long-term, low-dose vitamin C pretreated rats had decreased brain infarct size and decreased neurological deficit score compared with the vehicle or single high dose pretreated MCAO rats. Furthermore, electrophysiological experiments using patch clamp technique showed that vitamin C increased the whole-cell current of the large-conductance Ca2+-activated K+ (BKCa) channel. Moreover, vitamin C increased the open probability of the channel without change its amplitude. Importantly, blockade of the BKCa channels abolished the neuroprotective effect of vitamin C on MCAO. Therefore, this study shows that long-term, low-dose pretreatment with vitamin C could reduce MCAO-induced brain damage through activation of the BKCa channels, suggesting that the BKCa channel is a molecular target of vitamin C on stroke.

Value of carotid Doppler ultrasound and brain CT scan in ischemic stroke

Sonographic evaluation of the carotid arteries, both gray scale and Doppler is widely used for risk assessment for cerebrovascular accidents .This study was conducted to assess the state of carotid vessels in patients with acute ischemic stroke by assessing intima-media thickness of common carotid , internal carotid stenosis with the size of ischemic area that diagnosed by using computed tomography . : A total of 68 patient with stroke (21 females , 47 males) were assesed, Gray scale &amp; Doppler US of the ipsilateral carotid arteries performed , measurement of IMT of CCA , the presence of any plaque recorded , the diameter reduction measurement PSV &amp; EDV of the CCA &amp; ICA . 36 patient have no stenosis (52.94%), 32 remaining patient have different degree of stenosis (47.05%),as follow .19 patient have mild stenosis (H1)(59.37%), 9 patient have moderate stenosis (H2)(28.12%) , 4 patient have sever stenosis(H3)(12.5%).40 patient showed increased IMT (58.82%), 28 patient had normal IMT (41.17%).42 patients are smokers (61.76%),So increased intimal media thickness of common carotid artery is associated with stroke .Large size ischemic stroke are more associated with high degree of internal carotid artery stenosis ,There is a significant relation between atheromatous plaque and size of brain infarction

Preservation of cognitive function following whole brain radiotherapy in patients with brain metastases: Complications, treatments, and the emerging role of memantine.

Whole brain radiotherapy is the mainstay of treatment for patients suffering from stage IV malignancies that have metastasized to the brain. Although this therapy is often effective at reducing tumor size and burden, it is associated with a spectrum of toxicities that often result in irreversible cognitive decline. Various drug and non-drug therapies have been evaluated to treat this neurotoxicity after whole brain radiotherapy is administered; however, currently available options have shown little benefit or come with side effects themselves that may outweigh the benefits of their use. For this reason, current investigations are focusing on preventing cognitive decline, rather than attempting to attenuate symptoms after they occur. Memantine has consistently shown promise in both in-vitro and in-vivo studies as a neuroprotective agent that may improve cognitive outcomes in patients undergoing whole brain radiotherapy. Memantine use prior to and during whole brain radiotherapy has been shown to significantly delay time to cognitive failure and reduce the rate of decline in memory, cognitive function, and processing speed. Its use has also been linked to significant decreases in brain edema, brain infarct size, and brain vasculature changes following whole brain radiotherapy. Memantine offers a promising safety profile with high tolerability and limited side effects. The objective of this article is to provide an overview of the target patient population, the neurotoxic effects of WBRT, current treatment options, and a summary of the available literature surrounding the use of memantine in this setting.

Iron Overload Exacerbates the Risk of Hemorrhagic Transformation After tPA (Tissue-Type Plasminogen Activator) Administration in Thromboembolic Stroke Mice.

Background and Purpose- Recanalization with tPA (tissue-type plasminogen activator) is the only pharmacological therapy available for patients with ischemic stroke. However, the percentage of patients who may receive this therapy is limited by the risk of hemorrhagic transformation (HT)-the main complication of ischemic stroke. Our aim is to establish whether iron overload affects HT risk, to identify mechanisms that could help to select patients and to prevent this devastating complication. Methods- Mice fed with control or high-iron diet were subjected to thromboembolic stroke, with or without tPA therapy at different times after occlusion. Blood samples were collected for determination of malondialdehyde, matrix metalloproteinases, and fibronectin. Brain samples were collected 24 hours after occlusion to determine brain infarct and edema size, hemorrhage extension, IgG extravasation, and inflammatory and oxidative markers (neutrophil infiltration, 4-hydroxynonenal, and matrix metalloproteinase-9 staining). Results- Despite an increased rate of recanalization, iron-overload mice showed less neuroprotection after tPA administration. Importantly, iron overload exacerbated the risk of HT after early tPA administration, accelerated ischemia-induced serum matrix metalloproteinase-9 increase, and enhanced basal serum lipid peroxidation. High iron increased brain lipid peroxidation at most times and neutrophil infiltration at the latest time studied. Conclusions- Our data showing that iron overload increases the death of the compromised tissues, accelerates the time of tPA-induced reperfusion, and exacerbates the risk of HT may have relevant clinical implications for a safer thrombolysis. Patients with stroke with iron overload might be at high risk of HT after fibrinolysis, and, therefore, clinical studies must be performed to confirm our results.

Tetramethylpyrazine‑2′O‑sodium ferulate provides neuroprotection against neuroinflammation and brain injury in MCAO/R rats by suppressing TLR-4/NF-κB signaling pathway

BackgroundNeuroinflammation following cerebral ischemia is a serious risk factor in stroke patients. The purpose of this study was to investigate the neuroprotective effects of tetramethylpyrazine‑2′O‑sodium ferulate (TSF), a structurally modified compound from tetramethylpyrazine and ferulate, on cerebral ischemic injury and the underlying mechanisms. MethodsFocal transient cerebral ischemia was induced in rat for 2 h by middle cerebral artery occlusion (MCAO) and the protective effect of TSF was studied using different doses of the drug (10.8, 18, 30 mg/kg, intravenously); Ozagrel (18 mg/kg) was used as the positive control. The drugs were given immediately after MCAO and the efficacy and mechanisms were evaluated at 72 h of reperfusion. The level of pro-inflammatory cytokines such as TNF-α, IL-1β and anti-inflammatory molecules such as IL-10 was measured; other factors such as neurological deficit, brain water content and infarct size and the level of MCP-1, ICAM-1, iNOS, CD11b, TLR-4/NF-κBp65 were also measured. ResultsTSF at the doses of 18, 30 mg/kg significantly improved neurological deficit, reduced brain water content and infarct size, accompanied by a decrease in the concentration of TNF-α, IL-1β, MCP-1, ICAM-1, iNOS and an increase in the concentration of IL-10. The amount of CD11b and ICAM-1 was found largely decreased and the expression of TLR-4 and the nuclear NF-κBp65 was weakened in TSF-treatment group. ConclusionsOur study suggests that TSF possesses a neuroprotective effect against ischemic stroke which might be mediated through suppression of the inflammatory pathways in the brain following ischemic stroke.