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BACKGROUND: After subarachnoid hemorrhage (SAH), early brain injury (EBI) and delayed cerebral ischemia (DCI) lead to poor outcomes. Discovery of biomarkers indicative of disease severity and predictive of DCI is important. We tested whether leucine-rich alpha-2-glycoprotein 1 (LRG1) is a marker of severity, DCI, and functional outcomes after SAH. METHODS: We performed untargeted proteomics using mass spectrometry in plasma samples collected at < 48 h of SAH in two independent discovery cohorts (n = 27 and n = 45) and identified LRG1 as a biomarker for DCI. To validate our findings, we used enzyme-linked immunosorbent assay and confirmed this finding in an internal validation cohort of plasma from 72 study participants with SAH (22 DCI and 50 non-DCI). Further, we investigated the relationship between LRG1 and markers of EBI, DCI, and poor functional outcomes (quantified by the modified Rankin Scale). We also measured cerebrospinal fluid (CSF) levels of LRG1 and investigated its relationship to EBI, DCI, and clinical outcomes. RESULTS: Untargeted proteomics revealed higher plasma LRG1 levels across EBI severity and DCI in both discovery cohorts. In the validation cohort, the levels of LRG1 were higher in the DCI group compared with the non-DCI group (mean (SD): 95 [44] vs. 72 [38] pg/ml, p < 0.05, Student’s t-test) and in study participants who proceeded to have poor functional outcomes (84 [39.3] vs. 72 [43.2] pg/ml, p < 0.05). Elevated plasma LRG1 levels were also associated with markers of EBI. However, CSF levels of LRG1 were not associated with EBI severity or the occurrence of DCI. CONCLUSIONS: Plasma LRG1 is a biomarker for EBI, DCI, and functional outcomes after SAH. Further studies to elucidate the role of LRG1 in the pathophysiology of SAH are needed.

Aneurysmal subarachnoid hemorrhage (aSAH) causes a robust inflammatory response which leads worse brain injury and poor outcomes. We investigated if stimulation of nicotinic acetylcholine α7 receptors (α7-AChR) (receptors shown to have anti-inflammatory effects) would reduce inflammation and improve outcomes. To investigate the level of peripheral inflammation after aSAH, inflammatory markers were measured in plasma samples collected in a cohort of aSAH patients. To study the effect of α7-AChR stimulation, SAH was induced in adult mice which were then treated with a α7-AChR agonist, galantamine, or vehicle. A battery of motor and cognitive tests were performed 24 h after subarachnoid hemorrhage. Mice were euthanized and tissue collected for analysis of markers of inflammation or activation of α7-AChR-mediated transduction cascades. A separate cohort of mice was allowed to survive for 28 days to assess long-term neurological deficits and histological outcome. Microglia cell culture subjected to hemoglobin toxicity was used to assess the effects of α7-AChR agonism. Analysis of eighty-two patient plasma samples confirmed enhanced systemic inflammation after aSAH. α7-AChR agonism reduced neuroinflammation at 24 h after SAH in male and female mice, which was associated with improved outcomes. This coincided with JAK2/STAT3 and IRAK-M activity modulations and a robust improvement in neurological/cognitive status that was effectively reversed by interfering with various components of these signaling pathways. Pharmacologic inhibition partially reversed the α7-AChR agonist’s benefits, supporting α7-AChR as a target of the agonist’s therapeutic effect. The cell culture experiment showed that α7-AChR agonism is directly beneficial to microglia. Our results demonstrate that activation of α7-AChR represents an attractive target for treatment of SAH. Our findings suggest that α7-AChR agonists, and specifically galantamine, might provide therapeutic benefit to aSAH patients.

Background Nucleotide-binding oligomerization domain-like receptor pyrin domain-containing protein 3 (NLRP3) plays an important role in mediating inflammatory responses during ischemic stroke. Bile acid receptor Takeda-G-protein-receptor-5 (TGR5) has been identified as an important component in regulating brain inflammatory responses. In this study, we investigated the mechanism of TGR5 in alleviating neuroinflammation after middle cerebral artery occlusion (MCAO). Methods Sprague-Dawley rats were subjected to MCAO and TGR5 agonist INT777 was administered intranasally 1 h after MCAO. Small interfering RNAs (siRNA) targeting TGR5 and Pellino3 were administered through intracerebroventricular injection 48 h before MCAO. Infarct volumes and neurologic scores were evaluated, and ELISA, flow cytometry, immunofluorescence staining, immunoblotting, and co-immunoprecipitation were used for the evaluations. Results Endogenous TGR5 and Pellino3 levels increased after MCAO. TGR5 activation by INT777 significantly decreased pro-inflammatory cytokine, cleaved caspase-8, and NLRP3 levels, thereby reducing brain infarctions; both short- and long-term neurobehavioral assessments showed improvements. Ischemic damage induced the interaction of TGR5 with Pellino3. Knockdown of either TGR5 or Pellino3 increased the accumulation of cleaved caspase-8 and NLRP3, aggravated cerebral impairments, and abolished the anti-inflammatory effects of INT777 after MCAO. Conclusions TGR5 activation attenuated brain injury by inhibiting neuroinflammation after MCAO, which could be mediated by Pellino3 inhibition of caspase-8/NLRP3.

Minimally invasive surgery has been widely used in the treatment of patients with intracerebral hemorrhage in recent years, and has achieved good clinical efficacy. Based on the basic theory of minimally invasive surgery, indications and contraindications are discussed, and then the minimally invasive preoperative preparation, intraoperative operation, postoperative management, and other aspects are systematically discussed. Finally, the application of microsurgery in the precise treatment of intracerebral hemorrhage is further prospected.

Brain vascular staining is very important for understanding cerebrovascular pathologies. 4% paraformaldehyde is considered the gold standard fixation technique for immunohistochemistry and it revolutionized the examination of proteins in fixed tissues. However, this fixation technique produces inconsistent immunohistochemical staining results due to antigen masking. Here, we test a new fixation protocol using 3% glyoxal and demonstrate that this method improves the staining of the brain vasculature, pericytes, and tight junction proteins compared to 4% paraformaldehyde. Use of this new fixation technique will provide more detailed information about vascular protein expressions, their distributions, and colocalizations with other proteins at the molecular level in the brain vasculature.

Brain vascular staining has great importance in understanding cerebrovascular pathologies. 4% Paraformaldehyde is considered as the gold standard fixation technique for immunohistochemistry and it revolutionized the examination of proteins in fixed tissues. However, this fixation technique produces inconsistent immunohistochemical staining results due to antigen masking. Here we test a new fixation protocol using 3% glyoxal and demonstrate that this method improves staining of the brain vasculature, pericytes, and tight junction proteins compared to 4% paraformaldehyde. Using this new fixation technique will provide more detailed information about vascular protein expressions, their distributions, and colocalizations with other proteins at the molecular level in the brain vasculature.

Brain vascular staining has great importance in understanding cerebrovascular pathologies. Paraformaldehyde 4% is considered the gold standard fixation technique for immunohistochemistry and it revolutionized the examination of proteins in fixed tissues. However, this fixation technique produces inconsistent immunohistochemical staining results due to antigen masking. Here we test a new fixation protocol using 3% glyoxal and demonstrate that this method provides overall better staining of the brain vasculature, pericytes, and tight junction proteins than 4% paraformaldehyde. Using this new fixation technique will provide more detailed information about vascular protein expressions, their distributions, and colocalizations with other proteins at the molecular level in the brain vasculature.

Sodium butyrate, a short-chain fatty acid, is predominantly produced by gut microbiota fermentation of dietary fiber and serves as an important neuromodulator in the central nervous system. Recent experimental evidence has suggested that sodium butyrate may be an endogenous ligand for two orphan G protein-coupled receptors, GPR41 and GP43, which regulate apoptosis and inflammation in ischemia-related pathologies, including stroke. In the present study, we evaluated the potential efficacy and mechanism of action of short-chain fatty acids in a rat model of middle cerebral artery occlusion (MCAO). Fatty acids were intranasally administered 1 h post MCAO. Short-chain fatty acids, especially sodium butyrate, reduced infarct volume and improved neurological function at 24 and 72 h after MCAO. At 24 h, the effects of MCAO, increased apoptosis, were ameliorated after treatment with sodium butyrate, which increased the expressions of GPR41, PI3K and phosphorylated Akt. To confirm these mechanistic links and characterize the GPR active subunit, PC12 cells were subjected to oxygen–glucose deprivation and reoxygenation, and pharmacological and siRNA interventions were used to reverse efficacy. Taken together, intranasal administration of sodium butyrate activated PI3K/Akt via GPR41/Gβγ and attenuated neuronal apoptosis after MCAO.

Aneurysmal subarachnoid hemorrhage (aSAH) patients develop delayed cerebral ischemia and delayed deficits (DCI) within 2 weeks of aneurysm rupture at a rate of approximately 30%. DCI is a major contributor to morbidity and mortality after SAH. The cause of DCI is multi-factorial with contributions from microthrombi, blood vessel constriction, inflammation, and cortical spreading depolarizations. Platelets play central roles in hemostasis, inflammation, and vascular function. Within this review, we examine the potential roles of platelets in microthrombi formation, large artery vasospasm, microvessel constriction, inflammation, and cortical spreading depolarization. Evidence from experimental and clinical studies is provided to support the role(s) of platelets in each pathophysiology which contributes to DCI. The review concludes with a suggestion for future therapeutic targets to prevent DCI after aSAH.

In addition to being the leading cause of morbidity and mortality in premature infants, germinal matrix hemorrhage (GMH) is also the leading cause of acquired infantile hydrocephalus. The pathophysiology of post-hemorrhagic hydrocephalus development after GMH is complex and vaguely understood, although evidence suggests fibrosis and gliosis in the periventricular and subarachnoid spaces disrupts normal cerebrospinal fluid dynamics. Theories explaining general hydrocephalus etiology have substantially evolved from the original bulk flow theory developed by Dr. Dandy over a century ago. Current clinical and experimental evidence supports a new hydrodynamic theory for hydrocephalus development involving redistribution of vascular pulsations and disruption of Starling forces in the brain microcirculation. In this review, we discuss cerebrospinal fluid flow dynamics, history and development of theoretical hydrocephalus pathophysiology, and GMH epidemiology and etiology as it relates to post-hemorrhagic hydrocephalus development. We highlight known mechanisms and propose new avenues that will further elucidate GMH pathophysiology, specifically related to hydrocephalus.

Disruption of the blood-brain barrier results in the formation of edema and contributes to the loss of neurological function following intracerebral hemorrhage (ICH). This study examined insulin-like growth factor-1 (IGF-1) as a treatment and its mechanism of action for protecting the blood-brain barrier after ICH in mice. 171 Male CD-1 mice were subjected to ICH via collagenase or autologous blood. A dose study for recombinant human IGF-1 (rhIGF-1) was performed. Brain water content and behavioral deficits were evaluated at 24 and 72 h after the surgery, and Evans blue extravasation and hemoglobin assay were conducted at 24 h. Western blotting was performed for the mechanism study and interventions were used targeting the IGF-1R/GSK3β/MEKK1 pathway. rhIGF-1 reduced edema and blood-brain barrier permeability, and improved neurobehavior outcomes. Western blots showed that rhIGF-1 reduced p-GSK3β and MEKK1 expression, thereby increasing occludin and claudin-5 expression. Inhibition and knockdown of IGF-1R reversed the therapeutic benefits of rhIGF-1. The findings within suggest that stimulation of the IGF-1R is a therapeutic target for ICH which may lead to improved neurofunctional and blood-brain barrier protection.

Aneurysmal subarachnoid hemorrhage (aSAH) causes a robust inflammatory response which leads worse brain injury and poor outcomes. We investigated if stimulation of nicotinic acetylcholine α(7) receptors (α(7)-AChR) (receptors shown to have anti-inflammatory effects) would reduce inflammation and improve outcomes. To investigate the level of peripheral inflammation after aSAH, inflammatory markers were measured in plasma samples collected in a cohort of aSAH patients. To study the effect of α(7)-AChR stimulation, SAH was induced in adult mice which were then treated with a α(7)-AChR agonist, galantamine, or vehicle. A battery of motor and cognitive tests were performed 24 h after subarachnoid hemorrhage. Mice were euthanized and tissue collected for analysis of markers of inflammation or activation of α(7)-AChR-mediated transduction cascades. A separate cohort of mice was allowed to survive for 28 days to assess long-term neurological deficits and histological outcome. Microglia cell culture subjected to hemoglobin toxicity was used to assess the effects of α(7)-AChR agonism. Analysis of eighty-two patient plasma samples confirmed enhanced systemic inflammation after aSAH. α(7)-AChR agonism reduced neuroinflammation at 24 h after SAH in male and female mice, which was associated with improved outcomes. This coincided with JAK2/STAT3 and IRAK-M activity modulations and a robust improvement in neurological/cognitive status that was effectively reversed by interfering with various components of these signaling pathways. Pharmacologic inhibition partially reversed the α(7)-AChR agonist’s benefits, supporting α(7)-AChR as a target of the agonist’s therapeutic effect. The cell culture experiment showed that α(7)-AChR agonism is directly beneficial to microglia. Our results demonstrate that activation of α(7)-AChR represents an attractive target for treatment of SAH. Our findings suggest that α(7)-AChR agonists, and specifically galantamine, might provide therapeutic benefit to aSAH patients. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13311-021-01052-3.

Subarachnoid hemorrhage induces neuronal apoptosis which causes acute and long-term memory deficits. Ourhypothesis is that agonism of α7-acetylcholine receptors attenuates neuronal apoptosis and improves memorydeficits in SAH mice. Mice were randomly assigned into the experimental groups. One cohort was euthanizedone day after SAH to assess neuronal apoptosis and signaling pathways. A second cohort survived for 30 dayspost-SAH to test long-term memory function. Inhibitors and an α7-acetylcholine receptor knockout mouse wereused. Neurobehavioral performance was assessed on days 1-3, 5, 7, and 23-28. All outcomes were performedand all data was analyzed by a blinded investigator. The α7-acetylcholine receptor agonist prevented neuronalapoptosis and improved acute memory deficits caused by SAH via activation of the PI3K/Akt pathway in neurons.Agonism of the α7-acetylcholine receptor was beneficial in both male and female mice, although the protectionin females was significantly better than in male mice. α7-acetylcholine receptor agonism did not provide anybenefit in α7-acetylcholine receptor knockout mice subjected to SAH. Treatment with the α7-acetylcholinereceptor agonist for 3 days after SAH led to improved working memory one month after SAH suggesting thatacutely improving neuronal survival can have long-lasting benefits. The α7-acetylcholine receptor may be atherapeutic target for SAH which can promote neuronal survival acutely after SAH, but also confer long-lastingmemory benefits. The findings of this study support the α7-acetylcholine receptor as a treatment target whichmay attenuate the long-term memory deficits which SAH patients suffer from.

The vessels of the central nervous system (CNS) have unique barrier properties. The endothelial cells (ECs) which comprise the CNS vessels contribute to the barrier via strong tight junctions, specific transporters, and limited endocytosis which combine to protect the brain from toxins and maintains brain homeostasis. Blood–brain barrier (BBB) leakage is a serious secondary injury in various CNS disorders like stroke, brain tumors, and neurodegenerative disorders. Currently, there are no drugs or therapeutics available to treat specifically BBB damage after a brain injury. Growing knowledge in the field of epigenetics can enhance the understanding of gene level of the BBB and has great potential for the development of novel therapeutic strategies or targets to repair a disrupted BBB. In this brief review, we summarize the epigenetic mechanisms or regulators that have a protective or disruptive role for components of BBB, along with the promising approaches to regain the integrity of BBB.

Background: Haptoglobin (Hp) binds to and facilitates clearance of heme. Compared with HP 1-1 and 1-2 genotypes, HP 2-2 has a weaker binding affinity and has been linked with increased inflammation and vasospasm after aneurysmal subarachnoid hemorrhage (SAH). Objective: This study aims to assess levels of inflammatory cytokines in the context of different HP genotypes. Methods: Patients were enrolled among those presenting with spontaneous aneurysmal SAH. Blood was drawn at four time points; Results: Fifty-seven patients were enrolled. Compared with HP 1-1 and 1-2, subjects encoding HP 2-2 had elevated levels of the following cytokines at all time points: FLT3L, IFNγ, IL-17A, TGFα, and VEGF-A. Elevations were also seen at some time points for IL-8, CSF2, FGF2, IL-7, IL-12p70, and TNFγ. This study was not powered to detect differences in the functional outcome; however, there were no significant differences in dichotomized mRS scores between patients with HP 1-1/1-2 or HP 2-2. Conclusion: Our findings indicate that HP 2-2 genotype leads to increased proinflammatory cytokine levels compared with HP 1-1/1-2 genotypes. These data may provide guidance for further studies seeking to identify testable markers for functional prognosis or targets for treatment.

Background and Purpose: Delayed neurological deficits are a devastating consequence of subarachnoid hemorrhage (SAH), which affects about 30% of surviving patients. Although a very serious concern, delayed deficits are understudied in experimental SAH models; it is not known whether rodents recapitulate the delayed clinical decline seen in SAH patients. We hypothesized that mice with SAH develop delayed functional deficits and that microthrombi and infarction correlate with delayed decline. Methods: Adult C57BL/6J mice of both sexes were subjected to endovascular perforation to induce SAH. Mice were allowed to survive for up to 1 week post-ictus and behavioral performance was assessed daily. Postmortem microthrombi, large artery diameters (to assess vasospasm), and infarct volume were measured. These measures were analyzed for differences between SAH mice that developed delayed deficits and SAH mice that did not get delayed deficits. Correlation analyses were performed to identify which measures correlated with delayed neurological deficits, sex, and infarction. Results: Twenty-three percent of males and 47% of females developed delayed deficits 3 to 6 days post-SAH. Female mice subjected to SAH had a significantly higher incidence of delayed deficits than male mice with SAH. Mice that developed delayed deficits had significantly more microthrombi and larger infarct volumes than SAH mice that did not get delayed deficits. Microthrombi positively correlated with infarct volume, and both microthrombi and infarction correlated with delayed functional deficits. Vasospasm did not correlate with either infarction delayed functional deficits. Conclusions: We discovered that delayed functional deficits occur in mice following SAH. Sex differences were seen in the prevalence of delayed deficits. The mechanism by which microthrombi cause delayed deficits may be via formation of infarcts.

The disruption of the blood-brain barrier (BBB) plays a critical event in the pathogenesis of ischemia stroke. TGR5 is recognized as a potential target for the treatment for neurologic disorders.This study investigated the roles of TGR5 activation in attenuating BBB damage and underlying mechanisms after middle cerebral artery occlusion (MCAO). Sprague-Dawley rats were subjected to model of MCAO and TGR5 agonist, INT777, was administered intranasally. Small interfering RNA (siRNA) for TGR5 and BRCA1 were administered through intracerebroventricular injection 48 h before MCAO. Infarct volumes, brain water content, BBB permeability, neurological scores, Western blot, immunofluorescence staining and co- immunoprecipitation were evaluated.Endogenous TGR5 and BRCA1 were upregulated in the injured hemisphere after MCAO and TGR5 expressed in endothelial cells. Treatment with INT777 alleviated brain water content and BBB permeability, reduced infarction volume and improved neurological scores at 24 h and 72 h after ischemia. INT777 administration increased BRCA1 and Sirt1 expression, as well as upregulated expressions of tight junction proteins. Ischemic damage induced interaction of TGR5 with BRCA1. TGR5 siRNA and BRCA1 siRNA significantly inhibited expressions of BRCA1 and Sirt1, aggravated BBB permeability and exacerbated stroke outcomes after MCAO. The protective effects of INT777 at 24 h after MCAO were also abolished by TGR5 siRNA or BRCA1 siRNA.Our findings demonstrate that activating TGR5 could reduce BBB breakdown and improve neurological functions through BRCA1/Sirt1 signaling pathway after MCAO. TGR5 may serve as a potential new candidate to relieve brain injury after MCAO.

The blood brain barrier (BBB), unique to the central nervous system (CNS) vessels, tightly controls the passage of molecules between the blood and the brain. BBB breakdown is documented in many pathological conditions including, stroke, and contributes to the severity of disease and poor outcome. Currently, there is no efficient treatment strategy to prevent BBB breakdown or restore disrupted BBB . Despite BBB’s importance in the CNS function, t he genetic program and mechanism, that regulates BBB formation and maintenance is poorly characterized. To understand the molecular features underlying BBB gene regulation during development we utilize endothelial cell (EC) cultures derived from brain of both embryonic (E-13.5) and adult mice and investigated differences in BBB gene expression and epigenetic status using real time PCR analysis and ChIP-qPCR. We found that a distinct BBB profile exist in the CNS ECs during BBB formation and maintenance . When compared to embryonic ECs, adult ECs showed a significant down regulation in expression of tight junction (TJ) genes such as CLDN-1 , CLDN -11 , ZO-1 and OCLN . Conversely, another important TJ gene CLDN- 5 shows a significant increase in adult ECs. Further, we found that epigenetic-histone modifications are involved in the repression in the TJ gene in adult ECs. To more fully understand the role of Wnt/β-catenin in BBB formation and maintenance we block the downstream of the Wnt/β-catenin signaling pathway using LF3 (block the interaction of β-catenin and transcription factor TCF4) in developing ECs. This results in a adult BBB phenotype in developing ECs indicating, silencing of Wnt/β-catenin pathway is required for BBB maturation . Further, epigenetic component HDAC2 was increased significantly in developing ECs when Wnt/β-catenin signaling is blocked demonstrating this pathway can modulate the epigenetics of CNS ECs . In summary, we describe that BBB genes have distinguished expression pattern during BBB formation and maintenance, guided by the Wnt/β-catenin pathway through epigenetic modifications. Understanding the fundamental epigenetic and regulatory mechanisms of BBB formation and maintenance is critical for developing therapeutic interventions against BBB breakdown.

Rationale: Microthrombosis has been suggested as a major factor contributing to delayed neurological deterioration in patients after subarachnoid hemorrhage (SAH). However, experimental studies on the role of microthrombi in delayed deficits after SAH has not been investigated. Our hypothesis is that, following SAH, mice which develop delayed neurological deficits have a greater number of microthrombi than mice which do not develop delayed neurological deficits. Methods: SAH was induced in adult male and female C57BL/6 mice via endovascular perforation. Mice were randomly assigned into sham (n=6/sex) or SAH groups (n=22-24/sex). Neurobehavior was performed on days 1-3, 5, and 7 post-SAH using a composite neuroscore. Animals were sacrificed on the day of delayed deficits or 7 days post-SAH. Microthrombi count and vessel diameters (for vasospasm) were measured using H&E stained brain slices. All outcomes were performed and all data were analyzed by a blinded investigator. Results: Seventeen percent (4/24) of male mice and thirty-six percent (8/22) of female mice developed delayed deficits on days 3-5 post-SAH (Figures 1A and 1B). Those mice which developed delayed deficits had significantly more microthrombi in their brains than mice which did not develop delayed deficits; vasospasm did not correlate with delayed deficits. Additionally, female SAH mice develop delayed deficits at a higher frequency than males (Figure 1C). Conclusions: This work shows for the first time delayed deficits in a SAH mouse model. Further, microthrombi correlated with delayed deficits, whereas no correlation was between delayed deficits and vasospasm. The data within this study suggests that preventing microthrombi may improve functional recovery and reduce the risk of delayed deficits.

Background: Autophagy is a prosurvival, reparative process that maintainsww cellular homeostasis through lyso-somal degradation of selected cytoplasmic components and programmed death of old, dysfunctional, or unnecessary cyto-plasmic entities. According to growing evidence, autophagy shows beneficial effects following subarachnoid hemorrhage (SAH). SAH is considered one of the most devastating forms of stroke. Methods: In this review lies in revealing the pathophysiological pathways and the effects of autophagy. Current results from animal studies will be discussed focusing on the effects of inhibitors and inducers of autophagy. In addition, this review dis-cusses the clinical translation of potential neuropharmacological targets that can help prevent early brain injury (EBI) follow-ing SAH by incorporating programmed cell death into clinical management. Results: Published data showed that autophagy mechanisms have a prosurvival effect to reduce apoptotic cell death after SAH. However, if SAH exceeds a certain stress threshold, autophagy mechanisms lead to increased apoptotic cell death, more brain injury, and worse outcome. Conclusion: Future investigation on the differences and molecular switches between protective mechanisms of autophagy and excessive “self-eating” autophagy leading to cell death is needed to achieve more insight into the complex pathophysiol-ogy of brain injury after SAH. If autophagy after SAH can be controlled to lead to beneficial effects only, as the physiologi-cal self-control mechanism, this could be an important target for treatment

Autophagy activation exerts neuroprotective effects in the ischemic stroke model. Ezetimibe (Eze), a Niemann-Pick disease type C1-Like 1 (NPC1L1) pharmacological inhibitor, has been reported to protect hepatocytes from apoptosis via autophagy activation. In this study, we explored whether Eze could attenuate neuronal apoptosis in the rat model of middle cerebral artery occlusion (MCAO), specifically via activation of the AMPK/ULK1/autophagy pathway. Two hundred and one male Sprague-Dawley rats were subjected to transient MCAO followed by reperfusion. Eze was administered 1 h after MCAO. To elucidate the underlying molecular mechanism, Dorsomorphin, a selective AMPK inhibitor, and 3-methyladenine (3-MA), an autophagy inhibitor, were injected intracerebroventricularly before MCAO. Infarct volume, neurological score, brain cholesterol levels, immunofluorescence staining, Western blot, and Fluoro-Jade C (FJC) staining were used to evaluate the effects of Eze. The endogenous NPC1L1 expression increased and mainly expressed in neurons after MCAO. Intranasal administration of Eze reduced brain infarct volume at 24 and 72 h after MCAO, with improved short and long-term neurological functions after MCAO. Eze reduced brain cholesterol levels (total cholesterol, free cholesterol and cholesteryl esters) and the number of FJC-positive neurons. The expression of phosphorylated AMPK (p-AMPK) and downstream ULK1, Beclin1, LC3BII, Bcl-2, and Bcl-xl increased, while P62 and proapoptotic Bax decreased after treatment with Eze. Pretreatment with Dorsomorphin and 3-MA reversed the beneficial effects of Eze. These findings suggest that intranasal administration of Eze plays neuroprotective role through autophagy activation after MCAO in rats. Lowered cholesterol levels and AMPK activation may act in conjunction to induce autophagy after treatment with Eze. Eze merits further investigation as a potential therapeutic agent in ischemic stroke patients.

In the brain, vascular endothelial cells conserve blood viscosity, control blood flow, and form the interface between central nervous system and circulating blood. Clinical outcome after aneurysmal subarachnoid hemorrhage is linked to early brain injury, cerebral vasospasm, and other causes of delayed cerebral ischemia. The cerebral vasculature remains a unique target for therapies since it becomes rapidly disrupted after subarachnoid hemorrhage, and damage to the blood vessels continues into the delayed injury phase. The current failure of therapies to improve clinical outcome warrants a re-evaluation of current therapeutic approaches. The mechanisms of endothelial cell injury and blood-brain barrier breakdown are critical to the pathway of cerebral injury, and an improved understanding of these mechanisms may lead to novel therapeutic targets. This review provides an update on the current understanding of endothelial cell injury following aneurysmal subarachnoid hemorrhage, including blood-brain barrier dysfunction.

Background and purpose Ischemic stroke activates Toll-like receptors (TLRs), triggering rapid inflammatory cytokine production. Axl signaling has multiple roles, including regulating cytokine secretion, clearing apoptotic cells, and maintaining cell survival, however, its role in inflammation after ischemic stroke has not been examined. We hypothesized that activation of Axl by recombinant Growth-arrest-specific protein 6 (rGas6) attenuates neuroinflammation by inhibiting the TLR/TRAF/NF-κB pathway after middle cerebral artery occlusion (MCAO) in rats. Meth Sprague-Dawley rats were subjected to 2 h of MCAO. One hour after reperfusion, the rats were given an intranasal injection of rGas6, vehicle, or R428 (Axl receptor inhibitor). Neurological scores, infarct volumes, immunofluorescence staining, Morris Water Maze, rotarod test and histology alterations were analyzed. The expressions of proinflammatory cytokines, including IL-1β, IL-6, TNF-α, and Gas6, Axl, STAT1, SOCS1, SOCS3 and the TLR/TRAF/NF-κB pathway were quantified using Western blot. Results Endogenous expressions of Gas6 and Axl decreased significantly by 24 h after MCAO. rGas6 reduced brain infarction and improved neurologic deficits scores, and increased expression of Axl and decreased the expressions of TRAF3, TRAF6 and inflammatory factors IL-1β, IL-6, and TNF-α. Four weeks after MCAO, rGas6 improved long-term neurological behavior and memory. Inhibition of the Axl/TLR/TRAF/NF-κB pathway reversed the brain protection by rGas6. Conclusion rGas6 reduced the neurological deficits by inhibiting neuroinflammation via the TLR/TRAF/NF-κB signaling pathway. rGas6 can be used as potential treatment to ischemic stroke.

Germinal matrix hemorrhage is induced by stereotaxic injection of collagenase into the germinal matrix of P7 Sprague-Dawley rats. Hemoglobin assay, western blot, immunofluorescence and neurobehavioral tests were used to test the effects of BLVRA on hematoma resolution and anti-inflammatory response. We showed that BLVRA triggered a signaling cascade that ameliorated post-hemorrhagic neurological deficits in both short-term and long-term neurobehavioral tests in a GMH rat model. Specifically, BLVRA inhibited toll-like receptor 4 (TLR4) expression by translocating to the nucleus in an endothelial nitric oxide (eNOS)/nitric oxide (NO)-dependent manner. BLVRA also induced the upregulation of CD36 scavenger receptor level in microglia/microphages, of which the prominent role is to enhance hematoma resolution. However, the beneficial effects of BLVRA were abolished with the knockdown of eNOS, indicating that the eNOS/NO system is an important downstream factor of BLVRA. Our results demonstrate a mechanism of BLVRA modulating hematoma resolution and suppressing inflammation through eNOS/NO/TLR4 pathway in the GMH rat model.

Subarachnoid hemorrhage (SAH) results in severe neuronal dysfunction and degeneration. Since the nicotinic acetylcholine α(7) receptors (α(7)-AChR) are involved in neuronal function and survival, we investigated if stimulation of α(7)-AChR would promote neuronal survival and improve behavioral outcome following SAH in mice. Male mice subjected to SAH were treated with either galantamine (α(7)-AChR agonist) or vehicle. Neurobehavioral testing was performed 24 hours after SAH, and mice were euthanized for analysis of neuronal cell death or a cell survival (PI3K/Akt) signaling pathway. Neuron cell cultures were subjected to hemoglobin toxicity to assess the direct effects of α(7)-AChR agonism independent of other cells. Treatment with the α(7)-AChR agonist promoted neuronal survival and improved functional outcomes 24 hours post-SAH. The improved outcomes corresponded with increased PI3K/Akt activity. Antagonism of α(7)-AChR or PI3K effectively reversed galantamine’s beneficial effects. Tissue from α(7)-AChR knockout mice confirmed α(7)-AChR’s role in neuronal survival after SAH. Data from the neuronal cell culture experiment supported a direct effect of α(7)-AChR agonism in promoting cell survival. Our findings indicate that α(7)-AChR is a therapeutic target following SAH which can promote neuronal survival, thereby improving neurobehavioral outcome. Thus, the clinically relevant α(7)-AChR agonist, galantamine, might be a potential candidate for human use to improve outcome after SAH.

Introduction Postoperative cerebral edema is a devastating complication in neurosurgical patients. Loss of blood-brain barrier integrity has been shown to lead to the development of brain edema following neurosurgical procedures. The aim of this study was to evaluate preconditioning with Crotalus helleri venom (Cv-PC) as a potential preventive therapy for reducing postoperative brain edema in the rodent SBI model. C. helleri venom is known to contain phospholipase A2 (PLA2), an enzyme upstream to cyclooxygenase-2 (COX-2) in the inflammatory cascade, acts to increase the production of inflammatory mediators, such as prostaglandins. We hypothesize that Cv-PC will downregulate the response of the COX-2 pathway to injury, thereby reducing the inflammatory response and the development of brain edema after SBI. Materials and methods 75 male Sprague Dawley rats (280–330 g) were divided to the following groups—naive + vehicle, naive + Cv-PC, sham, vehicle, Cv-PC, Cv-PC + NS398 (COX-2 inhibitor). Vehicle preconditioned and Cv-PC animals received either three daily subcutaneous doses of saline or C. helleri venom at 72 h, 48 h, and 24 h prior to surgery. In Cv-PC + NS398 animals, NS398 was administered intraperitoneally 1 h prior to each Cv-PC injection. Sham-operated animals received craniotomy only, whereas SBI animals received a partial right frontal lobectomy. Neurological testing and brain water content were assessed at 24 h and 72 h after SBI; COX-2 and PGE2 expression was assessed at 24 h postoperatively by Western blot and immunohistochemistry, respectively. Results At 24 h after SBI, the vehicle-treated animals were observed to have increased brain water content (83.1 ± 0.2%) compared to that of sham animals (80.2 ± 0.1%). The brain water content of vehicle-treated animals at 72 h post-SBI was elevated at 83.3 ± 0.2%. Cv-PC-treated animals with doses of 10% LD50 had significantly reduced brain water content of 81.92 ± 0.7% and 81.82 ± 0.3% at 24 h and 72 h, respectively, after SBI compared to that of vehicle-treated animals, while Cv-PC with 5% LD50 doses showed brain water content that trended lower but did not reach statistical significance. At 24 h and 72 h post-SBI, Cv-PC-treated animals had significantly higher neurological score than vehicle-treated animals. The COX-2 over-expression characterized in SBI was attenuated in Cv-PC-treated animals; NS398 reversed the protective effect of Cv-PC on COX-2 expression. Cv-PC tempered the over-expression of the inflammatory marker PGE2. Conclusion Our findings indicate that Cv-PC may provide a promising therapy for reducing postoperative edema and improving neurological function after neurosurgical procedures.

Cerebellar haemorrhage accounts for 5–10% of all intracerebral haemorrhages and leads to severe, long-lasting functional deficits. Currently, there is limited research on this stroke subtype, which may be due to the lack of a suitable composite neuroscoring system specific for cerebellar injury in rodents. The purpose of this study is to develop a comprehensive composite neuroscore test for cerebellar injury using a rat model of cerebellar haemorrhage. Sixty male Sprague-Dawley rats were subjected to either sham surgery or cerebellar haemorrhage. Twenty-four hours post-injury, neurological behaviour was evaluated using 17 cost-effective and easy-to-perform tests, and a composite neuroscore was developed. The composite neuroscore was then used to assess functional recovery over seven days after cerebellar haemorrhage. Differences in the composite neuroscore deficits for the mild and moderate cerebellar haemorrhage models were observed for up to five days post-ictus. Until now, a composite neuroscore for cerebellar injury was not available for rodent studies. Herein, using mild and moderate cerebellar haemorrhage rat models a composite neuroscore for cerebellar injury was developed and used to assess functional deficits after cerebellar haemorrhage. This composite neuroscore may also be useful for other cerebellar injury models.