Release of IL-6 After Stroke Contributes to Impaired Cerebral Autoregulation and Hippocampal Neuronal Necrosis Through NMDA Receptor Activation and Upregulation of ET-1 and JNK

Associations of Rheumatoid Factor, Rheumatoid Arthritis, and Interleukin-6 Inhibitor with the Prognosis of Ischemic Stroke: a Prospective Multicenter Cohort Study and Mendelian Randomization Analysis

Rheumatoid factor (RF), an established diagnostic biomarker for rheumatoid arthritis (RA), is associated with cardiovascular diseases, but its impact on clinical outcomes of ischemic stroke remains unclear. We aimed to investigate the observational associations between serum RF and prognosis of ischemic stroke, and further examined the genetic associations of RA and its therapeutic strategy, interleukin-6 (IL-6) inhibitor, with prognosis of ischemic stroke. We measured serum RF levels in 3474 Chinese ischemic stroke patients from the China Antihypertensive Trial in Acute Ischemic Stroke. The primary outcome was the composite outcome of death or major disability (modified Rankin Scale score ≥3) at 3 months after stroke onset. Mendelian randomization (MR) analyses were performed to examine the associations of genetically predicted RA and IL-6 inhibition with prognosis of ischemic stroke. During 3 months of follow-up, 866 patients (25.43%) experienced death or major disability. After multivariate adjustment, RF-positive was significantly associated with a high risk of primary outcome (OR, 1.47; 95% CI, 1.08-2.00; P =0.016) compared with RF-negative. The two-sample MR analyses suggested that genetically predicted RA was associated with an increased risk of primary outcome (OR, 1.09; 95% CI, 1.01-1.18; P=0.021), while genetically predicted IL-6 inhibition was associated with a decreased risk of primary outcome (OR, 0.88; 95% CI, 0.77-0.99; P=0.041). We found that positive RF was associated with increased risks of adverse outcomes after atherosclerotic ischemic stroke, and genetically predicted RA and IL-6 inhibition increased and decreased the risks of adverse outcomes after ischemic stroke, respectively.

Therapeutic effect and psychological impact of aspirin plus edaravone on patients with cerebral infarction

BACKGROUND

Cerebral infarction (CI) is characterized by a high prevalence, disability, and mortality. Timely or improper treatment greatly affects patient prognosis.

AIM

To explore the drug efficacy of aspirin plus edaravone and to explore their effect on quality of life (QOL), anxiety and depression in CI patients.

METHODS

We retrospectively analyzed the records of 124 CI patients treated between June 2019 and February 2021 who were assigned to an observation group (OG) (combination therapy of aspirin and edaravone, 65 patients) or a control group (CG) (aspirin monotherapy, 59 patients). The therapeutic effects, pre- and posttreatment National Institutes of Health Stroke Scale (NIHSS) scores, activities of daily living, degree of cognitive impairment, protein levels of glial fibrillary acidic protein (GFAP), neuron-specific enolase (NSE) and S-100B, occurrence of adverse reactions, and serum high-sensitivity C-reactive protein (hs-CRP), interleukin (IL)-6 and tumor necrosis factor (TNF)-α were evaluated, detected and compared between the two groups. Finally, posttreatment QOL, anxiety, and depression were assessed by the Medical Outcomes Study 36- Item Short Form Health Survey Scale, Self-rating Depression Scale (SDS), and Self-rating Anxiety Scale (SAS), respectively.

RESULTS

Compared with the CG, the OG had markedly better therapeutic effects, greater improvements in activities of daily living, and better alleviation in cognitive dysfunction after treatment, as well as lower posttreatment NIHSS scores and serum NSE, GFAP, S-100B, hs-CRP, IL-6, and TNF-α levels; the OG was similar to the CG in terms of adverse reactions but was better than the CG in terms of posttreatment QOL; and the OG also had lower SDS and SAS scores than the CG after treatment.

CONCLUSION

Aspirin plus edaravone had a good curative effect on CI. It can reverse cranial nerve damage in patients, improve neurological function and prognosis, and alleviate inflammation, anxiety, and depression; thus, it is considered safe and worthy of clinical application.

Inflammation biomarkers in the intracranial blood are associated with outcome in patients with ischemic stroke

BACKGROUND

Performing endovascular treatment (EVT) in patients with acute ischemic stroke (AIS) allows a port of entry for intracranial biological sampling.

OBJECTIVE

To test the hypothesis that specific immune players are molecular contributors to disease, outcome biomarkers, and potential targets for modifying AIS.

METHODS

We examined 75 subjects presenting with large vessel occlusion of the anterior circulation and undergoing EVT. Intracranial blood samples were obtained by microcatheter aspiration, as positioned for stent deployment. Peripheral blood samples were collected from the femoral artery. Plasma samples were quality controlled by electrophoresis and analyzed using a Mesoscale multiplex for targeted inflammatory and vascular factors.

RESULTS

We measured 37 protein biomarkers in our sample cohort. Through multivariate analysis, adjusted for age, intravenous thrombolysis, pretreatment National Institutes of Health Stroke Scale and Alberta Stroke Program Early CT scores, we found that post-clot blood levels of interleukin-6 (IL-6) were significantly correlated (adjusted P value <0.05) with disability assessed by the modified Rankin Scale (mRS) score at 90 days, with medium effect size. Chemokine (C-C) ligand 17 CCL17/TARC levels were inversely correlated with the mRS score. Examination of peripheral blood showed that these correlations did not reach statistical significance after correction. Intracranial biomarker IL-6 level was specifically associated with a lower likelihood of favorable outcome, defined as a mRS score of 0-2.

CONCLUSIONS

Our findings show a signature of blood inflammatory factors at the cerebrovascular occlusion site. The correlations between these acute-stage biomarkers and mRS score outcome support an avenue for add-on and localized immune modulatory strategies in AIS.

Bioinformatics analysis and experimental validation revealed that Paeoniflorigenone effectively mitigates cerebral ischemic stroke by suppressing oxidative stress and inflammation

Inflammation and oxidative stress are becoming more recognized as risk factors for ischemic stroke. Paeoniflorigenone (PA) has diverse pharmacological effects that include anti-inflammatory and antioxidant properties. However, the specific mechanisms by which PA affects cerebral ischemic stroke have not been studied. Our objective was to investigate the potential targets and mechanisms of PA in preventing cerebral ischemic stroke. We obtained the potential targets of PA from the SwissTargetPrediction, Super-PRED, and SEA Search Server databases. The GSE97537 dataset was utilized to identify gene targets related to ischemic stroke. The overlapping targets were imported into the STRING database to construct a protein-protein interaction network, and enrichment analyses were conducted using R software. Rats were pretreated with PA for three weeks before undergoing MCAO and reperfusion. H&E staining, ELISA, and qRT-PCR analyses were then performed to explore the potential mechanisms of PA. In the study, we identified 439 potential targets for PA and 1206 potential targets for ischemic stroke. Out of these, there were 71 common targets, which were found to be primarily associated with pathways related to oxidative stress and inflammation. The results from animal experiments showed that PA was able to improve nerve function and reduce inflammatory cytokines and oxidative stress in the MCAO-induced ischemic stroke model. Additionally, the expression of core genes in the MCAO + HPA group was significantly lower compared to the MCAO group. Our study revealed that the potential mechanisms by which PA prevents ischemic stroke involve oxidative stress and inflammation. These findings provide important theoretical guidance for the clinical use of PA in preventing and managing ischemic stroke.

Quercetin Protects Against Global Cerebral ischemia‒reperfusion Injury by Inhibiting Microglial Activation and Polarization

Background

This study aims to investigate the protective effect of quercetin against global cerebral ischemia‒reperfusion (GCI/R) injury in rats and elucidate the underlying mechanism.

Methods

A GCI/R injury rat model was established using a four-vessel occlusion (4-VO) method. An oxygen-glucose deprivation/reoxygenation (OGD/R) injury model was induced in BV2 cells. The extent of injury was assessed by evaluating neurological deficit scores (NDS) and brain water content and conducting behavioral tests. Pathomorphological changes in the prefrontal cortex were examined. Additionally, the study measured the levels of inflammatory cytokines, the degree of microglial activation and polarization, and the protein expression of Toll-like receptor 4 (TLR4) and TIR-domain-containing adaptor inducing interferon-β (TRIF).

Results

Quercetin pretreatment significantly ameliorated neurological impairment, improved learning and memory abilities, and reduced anxiety in rats subjected to GCI/R injury. Furthermore, quercetin administration effectively mitigated neuronal injury and brain edema. Notably, it suppressed microglial activation and hindered polarization toward the M1 phenotype. Simultaneously, quercetin downregulated the expression of TLR4 and TRIF proteins and attenuated the release of IL-1β and TNF-α.

Conclusion

This study highlights the novel therapeutic potential of quercetin in alleviating GCI/R injury. Quercetin demonstrates its neuroprotective effects by inhibiting neuroinflammation and microglial activation while impeding their transformation into the M1 phenotype through modulation of the TLR4/TRIF pathway.

Traditional Chinese medicines treat ischemic stroke and their main bioactive constituents and mechanisms

Ischemic stroke (IS) remains one of the leading causes of death and disability in humans. Unfortunately, none of the treatments effectively provide functional benefits to patients with IS, although many do so by targeting different aspects of the ischemic cascade response. The advantages of traditional Chinese medicine (TCM) in preventing and treating IS are obvious in terms of early treatment and global coordination. The efficacy of TCM and its bioactive constituents has been scientifically proven over the past decades. Based on clinical trials, this article provides a review of commonly used TCM patent medicines and herbal decoctions indicated for IS. In addition, this paper also reviews the mechanisms of bioactive constituents in TCM for the treatment of IS in recent years, both domestically and internationally. A comprehensive review of preclinical and clinical studies will hopefully provide new ideas to address the threat of IS.

Investigating the Potential Mechanisms and Therapeutic Targets of Inflammatory Cytokines in Post-stroke Depression

Post-stroke depression (PSD) affects approximately one-third of stroke survivors, severely impacting general recovery and quality of life. Despite extensive studies, the exact mechanisms underlying PSD remain elusive. However, emerging evidence implicates proinflammatory cytokines, including interleukin-1β, interleukin-6, tumor necrosis factor-alpha, and interleukin-18, play critical roles in PSD development. These cytokines contribute to PSD through various mechanisms, including hypothalamic-pituitary-adrenal (HPA) axis dysfunction, neurotransmitter alterations, neurotrophic factor changes, gut microbiota imbalances, and genetic predispositions. This review is aimed at exploring the role of cytokines in stroke and PSD while identifying their potential as specific therapeutic targets for managing PSD. A more profound understanding of the mechanisms regulating inflammatory cytokine expression and anti-inflammatory cytokines like interleukin-10 in PSD may facilitate the development of innovative interventions to improve outcomes for stroke survivors experiencing depression.

Analysis of cerebral Interleukin-6 and tumor necrosis factor alpha patterns following different ventilation strategies during cardiac arrest in pigs

Hypoxia-induced neuroinflammation after cardiac arrest has been shown to be mitigated by different ventilation methods. In this prospective randomized animal trial, 35 landrace pigs were randomly divided into four groups: intermittent positive pressure ventilation (IPPV), synchronized ventilation 20 mbar (SV 20 mbar), chest compression synchronized ventilation 40 mbar (CCSV 40 mbar) and a control group (Sham). After inducing ventricular fibrillation, basic life support (BLS) and advanced life support (ALS) were performed, followed by post-resuscitation monitoring. After 6 hours, the animals were euthanized, and direct postmortem brain tissue samples were taken from the hippocampus (HC) and cortex (Cor) for molecular biological investigation of cytokine mRNA levels of Interleukin-6 (IL-6) and tumor necrosis factor alpha (TNFα). The data analysis showed that CCSV 40 mbar displayed low TNFα mRNA-levels, especially in the HC, while the highest TNFα mRNA-levels were detected in SV 20 mbar. The results indicate that chest compression synchronized ventilation may have a potential positive impact on the cytokine expression levels post-resuscitation. Further studies are needed to derive potential therapeutic algorithms from these findings.

NMDA receptor inhibitor MK801 alleviated pro-inflammatory polarization of BV-2 microglia cells

Microglia have both protective and pathogenic properties, while polarization plays a decisive role in their functional diversity. Apart from being an energetic organelle, mitochondria possess biological capabilities of signaling and immunity involving mitochondrial dynamics. The N-methyl-D-aspartate (NMDA)-type glutamate receptor displays excitatory neurotransmission, excitatory neurotoxicity and pro-inflammatory properties in a membrane location- and cell context-dependent manner. In this study, we have provided experimental evidence showing that by acting on mitochondrial dynamics, NMDA receptors displayed pro-inflammatory properties, while its non-competitive inhibitor MK801 exhibited anti-inflammatory potential in Lipopolysaccharide (LPS)-challenged BV-2 microglia cells. LPS stimulation increased the protein phosphorylation of cells regarding their NMDA receptor component subunits and Calcium/Calmodulin-dependent Protein Kinase II (CaMKII), along with mobilizing intracellular calcium. Additionally, parallel changes occurred in the activation of Transforming Growth Factor-β (TGF-β)-Activated Kinase 1 (TAK1), NF-κB p65 and NF-κB DNA binding activity, acquisition of pro-inflammatory M1 polarization and expression of pro-inflammatory cytokines. LPS-treated cells further displayed signs of mitochondrial dysfunction with higher expressions of the active form of Dynamin-Related Protein 1 (Drp1), NADPH Oxidase-2 (NOX2) expression and the generation of DCFDA-/MitoSOX-sensitive Reactive Oxygen Species (ROS). NMDA receptor blockade by MK801, along with CaMKII inhibitor KN93, Drp1 inhibitor Mdivi-1 and antioxidant apocynin alleviated LPS-induced pro-inflammatory changes. Other than the reported CaMKII/TAK1/NF-κB axis, our in vitro study revealed the CaMKII/Drp1/ROS/NF-κB axis being an alternative cascade for shaping pro-inflammatory phenotypes of microglia upon LPS stimulation, and MK801 having the potential for inhibiting microglia activation and any associated inflammatory damages.

Insight into the transcription factors regulating Ischemic Stroke and Glioma in Response to Shared Stimuli

Cerebral ischemic stroke and glioma are the two leading causes of patient mortality globally. Despite physiological variations, 1 in 10 people who have an ischemic stroke go on to develop brain cancer, most notably gliomas. In addition, glioma treatments have also been shown to increase the risk of ischemic strokes. Stroke occurs more frequently in cancer patients than in the general population, according to traditional literature. Unbelievably, these events share multiple pathways, but the precise mechanism underlying their co-occurrence remains unknown. Transcription factors (TFs), the main components of gene expression programmes, finally determine the fate of cells and homeostasis. Both ischemic stroke and glioma exhibit aberrant expression of a large number of TFs, which are strongly linked to the pathophysiology and progression of both diseases. The precise genomic binding locations of TFs and how TF binding ultimately relates to transcriptional regulation remain elusive despite a strong interest in understanding how TFs regulate gene expression in both stroke and glioma. As a result, the importance of continuing efforts to understand TF-mediated gene regulation is highlighted in this review, along with some of the primary shared events in stroke and glioma.

Unwinding the modalities of necrosome activation and necroptosis machinery in neurological diseases

Necroptosis, a regulated form of cell death, is involved in the genesis and development of various life-threatening diseases, including cancer, neurological disorders, cardiac myopathy, and diabetes. Necroptosis initiates with the formation and activation of a necrosome complex, which consists of RIPK1, RIPK2, RIPK3, and MLKL. Emerging studies has demonstrated the regulation of the necroptosis cell death pathway through the implication of numerous post-translational modifications, namely ubiquitination, acetylation, methylation, SUMOylation, hydroxylation, and others. In addition, the negative regulation of the necroptosis pathway has been shown to interfere with brain homeostasis through the regulation of axonal degeneration, mitochondrial dynamics, lysosomal defects, and inflammatory response. Necroptosis is controlled by the activity and expression of signaling molecules, namely VEGF/VEGFR, PI3K/Akt/GSK-3β, c-Jun N-terminal kinases (JNK), ERK/MAPK, and Wnt/β-catenin. Herein, we briefly discussed the implication and potential of necrosome activation in the pathogenesis and progression of neurological manifestations, such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, traumatic brain injury, and others. Further, we present a detailed picture of natural compounds, micro-RNAs, and chemical compounds as therapeutic agents for treating neurological manifestations.

A GP130-Targeting Small Molecule, LMT-28, Reduces LPS-Induced Bone Resorption around Implants in Diabetic Models by Inhibiting IL-6/GP130/JAK2/STAT3 Signaling

In this study, we examined the effect of the GP130-targeting molecule, LMT-28, on lipopolysaccharide- (LPS-) induced bone resorption around implants in diabetic models using in vitro and rat animal experiments. First, LMT-28 was added to osteoblasts stimulated by LPS and advanced glycation end products (AGEs), and nuclear factor-κB receptor-activating factor ligand (RANKL) and associated pathways were evaluated. Then, LMT-28 was administered by gavage at 0.23 mg/kg once every 5 days for 2 weeks to type 2 diabetic rats with peri-implantitis induced by LPS injection and silk ligature. The expression of IL-6 and RANKL was evaluated by immunohistochemistry, and the bone resorption around implants was evaluated by microcomputed tomography. The results showed that LMT-28 downregulated the expression of RANKL through the JAK2/STAT3 signaling pathway in osteoblasts stimulated by LPS and AGEs, reduced bone resorption around implants with peri-implantitis, decreased the expression of IL-6 and RANKL, and decreased osteoclast activity in type 2 diabetic rats. This study confirmed the ability of LMT-28 to reduce LPS-induced bone resorption around implants in diabetic rats.

Mechanisms of cerebral vasospasm and cerebral ischaemia in subarachnoid haemorrhage

Subarachnoid haemorrhage (SAH) is a cerebrovascular emergency associated with significant morbidity and mortality. SAH is characterized by heterogeneity, interindividual variation and complexity of pathophysiological responses following extravasation of blood from cerebral circulation. The purpose of this review is to integrate previously established pre-existing factors, pathophysiological pathways and to develop a concept map of mechanisms of SAH-induced cerebral vasospasm and delayed cerebral ischaemia using a systematic approach. We conducted an extensive mapping of a hypothesized sequence of pathophysiological events. Documentation of supporting evidence was done alongside a concept map building. After finalizing the model, we conducted an analysis of the consequences and connections of pathophysiological events. We included the findings of experimental research, focusing on pathophysiological processes. We focused on SAH-induced cerebral vasospasm and delayed cerebral ischaemia as a component of cerebral injury and potential systemic consequences. SAH-induced brain injury occurs within 72 h following haemorrhage. Pathophysiology of cerebral vasospasm may include reduction in NO production, direct activation of calcium channels, upregulating genes involved with inflammation and extracellular matrix remodelling, triggering oxidative stress and free radical damage to smooth muscle and lipid peroxidation of cell membranes, cortical spreading depolarizations, sympathetic activation, finally resulting in the failure of cerebral autoregulation, microthrombosis and cerebral ischaemic injury. This cascade of events might explain why medical therapy often fails to reverse resistant cerebral vasospasm and to prevent cerebral ischaemia.

Sanhua decoction: Current understanding of a traditional herbal recipe for stroke

Both thrombolytic and endovascular therapies are optimal treatment options for patients with acute ischemic stroke, but only less than half of these patients can benefit from these treatments. Traditional Chinese medicine has a long history of successfully managing ischemic stroke using both herbal and physical therapeutics. Among herbal recipes, Sanhua decoction (SHD) is one of the classical prescriptions for ischemic stroke. The present review aimed to summarize evidence from both clinical and basic research to demonstrate its efficacy in managing ischemic stroke and the potential mechanisms underlying its therapeutic effects, which will provide evidence on the therapeutic effect of this herbal recipe and guide future studies on this recipe. SHD is composed of four herbs, Rheum palmatum L. [Polygonaceae], Magnolia officinalis Rehder & E.H.Wilson [Magnoliaceae], Citrus × aurantium L. [Rutaceae], Hansenia weberbaueriana (Fedde ex H.Wolff) Pimenov & Kljuykov [Apiaceae]. We found that the majority of clinical studies on SHD are case reports and they showed positive therapeutic effect of SHD on both acute and chronic ischemic stroke. There are over 40 bioactive compounds identified in SHD, but few experimental studies have examined their individual molecular mechanisms. As an extract of SHD, it improves neurological functions through suppressing inflammation, protecting the blood brain barrier from degradation, restoring the number of neural stem cells, inhibiting apoptosis and brain edema, scavenging oxygen free radicals, and regulating the brain-gut axis. These will lay the theoretical foundation for future studies on this prescription and its clinical application. Future research may need to confirm its clinical efficacy in large-scale clinical trials and to disentangle its bioactive compounds and their potential mechanisms.

Network pharmacology and in vitro experimental verification to explore the mechanism of Sanhua decoction in the treatment of ischaemic stroke

CONTEXT

Stroke is an illness with high morbidity, disability and mortality that presents a major clinical challenge. Sanhua decoction (SHD) has been widely used to treat ischaemic stroke in the clinic. However, the potential mechanism of SHD remains unknown.

OBJECTIVE

To elucidate the multitarget mechanism of SHD in ischaemic stroke through network pharmacology and bioinformatics analyses.

MATERIALS AND METHODS

Network pharmacology and experimental validation approach was used to investigate the bioactive ingredients, critical targets and potential mechanisms of SHD against ischaemic stroke. Four herbal names of SHD, 'ischemic stroke' or 'stroke' was used as a keyword to search the relevant databases. SH-SY5Y cells were treated with various concentrations of SHD (12.5, 25, 50 or 100 μg/mL) for 4 h, exposed to oxygen and glucose deprivation (OGD) for 1 h, then reoxygenation for 24 h. The cell viability was detected by MTT, the lactate dehydrogenase (LDH) was evaluated by ELISA, and protein expression was detected by western blots.

RESULTS

SHD treatment increased the survival rate from 65.9 ± 4.3 to 85.56 ± 5.7%. The median effective dose (ED₅₀) was 47.1 μg/mL, the LDH decreased from 288.0 ± 12.0 to 122.8 ± 9.1 U/L and the cell apoptosis rate decreased from 33.6 ± 1.8 to 16.3 ± 1.2%. Western blot analysis revealed that SHD increased the levels of p-PI3k, p-Akt and p-CREB1, and decreased the expression of TNF-α and IL-6.

DISCUSSION AND CONCLUSIONS

This study suggests that SHD protects against cerebral ischaemic injury via regulation of the PI3K/Akt/CREB1 and TNF pathways.

Diabetes and the treatment of ischemic stroke

This white paper examines the current challenges for treating ischemic stroke in diabetic patients. The need for a greater understanding of the mechanisms that underlie the relationship between diabetes and the cerebral vascular responses to ischemia is discussed. The critical need to improve the efficacy and safety of thrombolysis is addressed, as is the need for a better characterization the off-target actions of tPA, the only currently approved thrombolytic for the treatment of ischemic stroke.

Targeting NMDA Receptors at the Neurovascular Unit: Past and Future Treatments for Central Nervous System Diseases

The excitatory neurotransmission of the central nervous system (CNS) mainly involves glutamate and its receptors, especially N-methyl-D-Aspartate receptors (NMDARs). These receptors have been extensively described on neurons and, more recently, also on other cell types. Nowadays, the study of their differential expression and function is taking a growing place in preclinical and clinical research. The diversity of NMDAR subtypes and their signaling pathways give rise to pleiotropic functions such as brain development, neuronal plasticity, maturation along with excitotoxicity, blood-brain barrier integrity, and inflammation. NMDARs have thus emerged as key targets for the treatment of neurological disorders. By their large extracellular regions and complex intracellular structures, NMDARs are modulated by a variety of endogenous and pharmacological compounds. Here, we will present an overview of NMDAR functions on neurons and other important cell types involved in the pathophysiology of neurodegenerative, neurovascular, mental, autoimmune, and neurodevelopmental diseases. We will then discuss past and future development of NMDAR targeting drugs, including innovative and promising new approaches.

Salidroside Ameliorates Ischemia-Induced Neuronal Injury through AMPK Dependent and Independent Pathways to Maintain Mitochondrial Quality Control

Salidroside, an active ingredient in Rhodiola rosea, has potent protective activity against cerebral ischemia. However, the mechanisms underlying its pharmacological actions are poorly understood. In this study, we employed a mouse middle cerebral artery occlusion (MCAO) and cellular oxygen and glucose deprivation (OGD) models to test the hypothesis that salidroside may restore mitochondrial quality control in neurons by modulating the relevant signaling. The results indicated that salidroside mitigated almost 40% the ischemia-induced brain infarct volumes in mice and the OGD-decreased viability of neurons to ameliorate the mitochondrial functions. Furthermore, salidroside treatment alleviated the OGD- or ischemia-induced imbalance of mitochondrial fission and fusion, mitophagy and promoted mitochondrial biogenesis in neurons by attenuating the AMPK activity. Moreover, salidroside alleviated 50% the OGD-promoted mitochondrial calcium fluorescence intensity and 5% mitochondria-associated membrane (MAM) area by down-regulating GRP75 expression independent of the AMPK signaling. Finally, similar findings were achieved in primary mouse neurons. Collectively, these data indicate that salidroside effectively restores the mitochondria dynamics, facilitates mitochondrial biogenesis by attenuating the AMPK signaling, and maintains calcium homeostasis in neurons independent of the AMPK activity.

Triad3A-Dependent TLR4 Ubiquitination and Degradation Contributes to the Anti-Inflammatory Effects of Pterostilbene on Vascular Dementia

Pterostilbene, a methylated stilbene derived from many plant foods, has significant anti-inflammatory activity. Meanwhile, vascular dementia (VaD) is the second most common subtype of dementia, in which inflammation is one of the major pathogenic contributors. However, the protective effect of pterostilbene on VaD is not well understood. In this work, we investigated the effect of pterostilbene on VaD and explored its underlying mechanisms using in vivo and in vitro models. Y-maze and Morris water maze tests showed pterostilbene-attenuated cognitive impairment in mice with bilateral common carotid artery occlusion (BCCAO). The hippocampal neuronal death and microglial activation in BCCAO mice were also reduced by pterostilbene treatment. Further, pterostilbene inhibited the expression of TLR4 and downstream inflammatory cytokines in these mice, with similar results observed in an oxygen-glucose deprivation and reperfusion (OGD/R) BV-2 cell model. In addition, its anti-inflammatory effect on OGD/R BV-2 cells was partially blocked by TLR4 overexpression. Moreover, Triad3A-TLR4 interactions were increased by pterostilbene following enhanced ubiquitination and degradation of TLR4, and the inhibitory effect of pterostilbene on inflammation was blocked by Triad3A knockdown in OGD/R-stimulated BV-2 cells. Together, these results reveal that pterostilbene could reduce vascular cognitive impairment and that Triad3A-mediated TLR4 degradation might be the key target.

Cerebral blood flow self-regulation in depression

BACKGROUND

Depression is a common neuropsychiatric disease with a high prevalence rate. Sleep problems, memory decline, dizziness and headaches are the most common neurological symptoms in depressed patients. Abnormality of cerebral blood flow (CBF) has been observed in depressive patients, but those patients did not have intracranial structural damage. Both of those phenomena might be related to cerebral blood flow self-regulation (CBFSR: cerebral blood flow self-regulation). CBFSR can maintain CBF relatively stable in response to changes in neurological and metabolic factors. Therefore, this review aimed to discuss CBFSR in depression.

METHODS

We searched for keywords such as "depression", "cerebral blood flow", "cerebral autoregulation", "cerebrovascular reactivity" and the words related to depression. We analyzed whether there is a change in the CBFSR in depression, further explored whether there is a relationship between the pathogenesis of depression and the CBFSR, and discussed the possible mechanism of impaired CBFSR in patients with depression.

RESULTS

Discovered by the literature review, CBFSR is significantly impaired in depressed patients. The level of circulating markers of endothelial dysfunction, nitric oxide, inflammatory cytokines, glucocorticoid and monoamine neurotransmitters is mostly abnormal in depression, which affected the CBFSR to varying degrees.

LIMITATIONS

Limitations include the small number of direct studies about depression and CBFSR mechanisms.

CONCLUSION

CBFSR is impaired in depression. The underlying mechanisms include endothelial dysfunction, overactivation of microglia and changes of cytokines, hyperactivation of the HPA axis, increased oxidative stress, monoamine neurotransmitter disorders, etc. These deepened our understanding of the clinical symptoms of depressed patients.

Interleukins and Ischemic Stroke

Ischemic stroke after cerebral artery occlusion is one of the major causes of chronic disability worldwide. Interleukins (ILs) play a bidirectional role in ischemic stroke through information transmission, activation and regulation of immune cells, mediating the activation, multiplication and differentiation of T and B cells and in the inflammatory reaction. Crosstalk between different ILs in different immune cells also impact the outcome of ischemic stroke. This overview is aimed to roughly discuss the multiple roles of ILs after ischemic stroke. The roles of IL-1, IL-2, IL-4, IL-5, IL-6, IL-8, IL-9, IL-10, IL-12, IL-13, IL-15, IL-16, IL-17, IL-18, IL-19, IL-21, IL-22, IL-23, IL-32, IL-33, IL-34, IL-37, and IL-38 in ischemic stroke were discussed in this review.

Preconditioning With Intermittent Hypobaric Hypoxia Attenuates Stroke Damage and Modulates Endocytosis in Residual Neurons

Background: Moderate hypobaric hypoxia induces cerebral ischemic tolerance. We investigated the optimal method for applying hypobaric hypoxia preconditioning at 5,000 m to ischemic brain tissue and combined it with proteomics to determine the mechanisms underlying this effect. Methods: Male SD rats were randomly grouped as S (sham, n = 20), M (middle cerebral artery occlusion [MCAO], n = 28), H2M (intermittent hypobaric hypoxia preconditioned MCAO group, 2 h/day, 10 days, n = 20), H6M (intermittent hypobaric hypoxia preconditioned MCAO group, 6 h/day, 10 days, n = 28), and HpM (persistent hypobaric hypoxia preconditioned MCAO group, 10 days, n = 28). The permanent MCAO model was established based on the Zea Longa method. Infarction was assessed with the modified neurological severity score (mNSS) and 2,3,5-triphenyl tetrazolium chloride staining. The total protein expression of the neuron-specific nuclear protein (NeuN), cysteinyl aspartate specific proteinase 3 (caspase-3), cleaved-caspase-3, and interleukin 6 (IL-6) was determined using western blotting. We assessed the peri-infarct cortex's ultrastructural changes. A label-free proteomic study and western blot verification were performed on the most effective preconditioned group. Results: The H6M group showed a lower infarct volume (p = 0.0005), lower mNSS score (p = 0.0009) than the M group. The H2M showed a lower level of IL-6 (p = 0.0213) than the M group. The caspase-3 level decreased in the H2M (p = 0.0002), H6M (p = 0.0025), and HpM groups (p = 0.0054) compared with that in the M group. Cleaved-caspase-3 expression decreased in the H2M (p = 0.0011), H6M (p < 0.0001), and HpM groups (p < 0.0001) compared with that in the M group. The neurons' ultrastructure and the blood-brain barrier in the peri-infarct tissue improved in the H2M and H6M groups. Immunofluorescence revealed increased NeuN-positive cells in the peri-infarct tissue in the H6M group (p = 0.0003, H6M vs. M). Protein expression of Chmp1a, Arpc5, and Hspa2 factors related to endocytosis were upregulated in the H6M compared with those of the M group (p < 0.05 for all) on western blot verification of label-free proteomics. Conclusions: Intermittent hypobaric hypoxia preconditioning exerts a neuroprotective effect in a rat stroke model. Persistent hypobaric hypoxia stimulation exhibited no significant neuroprotective effect. Intermittent hypoxic preconditioning for 6 h/day for 10 days upregulates key proteins in clathrin-dependent endocytosis of neurons in the cortex.

Propofol ameliorates ischemic brain injury by blocking TLR4 pathway in mice

Ischemic brain injury is one of the most serious perioperative complications. However, effective preventative methods have not yet been established. This study aimed to investigate whether propofol has neuroprotective effects against ischemic brain injury, with a specific focus on Toll-like receptor 4 (TLR4). Focal brain ischemia was induced via a combination of left common carotid artery occlusion and distal left middle cerebral artery coagulation in mice. Either propofol (10 mg/kg) or vehicle was intravenously injected 10 min prior to the induction of brain ischemia in wild-type and TLR4 knockout mice. Infarct volume, pro-inflammatory cytokine expression, inflammatory cell infiltration, and neurobehavioral function were assessed. Propofol administration significantly reduced infarct volume in wild-type mice (26.9 ± 2.7 vs 15.7 ± 2.0 mm³ at day 7), but not in TLR4 knockout mice. Compared with the control mice, the propofol-treated wild-type mice exhibited lower levels of IL-6 (0.57 ± 0.23 vs 1.00 ± 0.39 at 24 h), and smaller numbers of TLR4-expressing microglia in the penumbra (11.7 ± 3.1 vs 25.1 ± 4.7 cells/0.1 mm²). In conclusion, propofol administration prior to ischemic brain insult attenuated brain injury by blocking the TLR4-dependent pathway and suppressing pro-inflammatory cytokine production.

Inflammation: A Mediator Between Hypertension and Neurodegenerative Diseases

Hypertension is the most prevalent and modifiable risk factor for stroke, vascular cognitive impairment, and Alzheimer's disease. However, the mechanistic link between hypertension and neurodegenerative diseases remains to be understood. Recent evidence indicates that inflammation is a common pathophysiological trait for both hypertension and neurodegenerative diseases. Low-grade chronic inflammation at the systemic and central nervous system levels is now recognized to contribute to the physiopathology of hypertension. This review speculates that inflammation represents a mediator between hypertension and neurodegenerative diseases, either by a decrease in cerebral blood flow or a disruption of the blood-brain barrier which will, in turn, let inflammatory cells and neurotoxic molecules enter the brain parenchyma. This may impact brain functions including cognition and contribute to neurodegenerative diseases. This review will thus discuss the relationship between hypertension, systemic inflammation, cerebrovascular functions, neuroinflammation, and brain dysfunctions. The potential clinical future of immunotherapies against hypertension and associated cerebrovascular risks will also be presented.

Protective Effects of Cannabidivarin and Cannabigerol on Cells of the Blood-Brain Barrier Under Ischemic Conditions

Background and Objectives: Preclinical studies have shown cannabidiol is protective in models of ischemic stroke. Based on results from our recent systematic review, we investigated the effects of two promising neuroprotective phytocannabinoids, cannabigerol (CBG) and cannabidivarin (CBDV), on cells of the blood-brain barrier (BBB), namely human brain microvascular endothelial cells (HBMECs), pericytes, and astrocytes. Experimental Approach: Cultures were subjected to oxygen-glucose deprivation (OGD) protocol to model ischemic stroke and cell culture medium was assessed for cytokines and adhesion molecules post-OGD. Astrocyte cell lysates were also analyzed for DNA damage markers. Antagonist studies were conducted where appropriate to study receptor mechanisms. Results: In astrocytes CBG and CBDV attenuated levels of interleukin-6 (IL-6) and lactate dehydrogenase (LDH), whereas CBDV (10 nM-10 μM) also decreased vascular endothelial growth factor (VEGF) secretion. CBDV (300 nM-10 μM) attenuated levels of monocyte chemoattractant protein (MCP)-1 in HBMECs. In astrocytes, CBG decreased levels of DNA damage proteins, including p53, whereas CBDV increased levels of DNA damage markers. Antagonists for CB₁, CB₂, PPAR-γ, PPAR-α, 5-HT1_A, and TRPV1 had no effect on CBG (3 μM) or CBDV (1 μM)-mediated decreases in LDH in astrocytes. GPR55 and GPR18 were partially implicated in the effects of CBDV, but no molecular target was identified for CBG. Conclusions: We show that CBG and CBDV were protective against OG mediated injury in three different cells that constitute the BBB, modulating different hallmarks of ischemic stroke pathophysiology. These data enhance our understanding of the protective effects of CBG and CBDV and warrant further investigation into these compounds in ischemic stroke. Future studies should identify other possible neuroprotective effects of CBG and CBDV and their corresponding mechanisms of action.

Neurovascular Units and Neural-Glia Networks in Intracerebral Hemorrhage: from Mechanisms to Translation

Intracerebral hemorrhage (ICH), the most lethal type of stroke, often leads to poor outcomes in the clinic. Due to the complex mechanisms and cell-cell crosstalk during ICH, the neurovascular unit (NVU) was proposed to serve as a promising therapeutic target for ICH research. This review aims to summarize the development of pathophysiological shifts in the NVU and neural-glia networks after ICH. In addition, potential targets for ICH therapy are discussed in this review. Beyond cerebral blood flow, the NVU also plays an important role in protecting neurons, maintaining central nervous system (CNS) homeostasis, coordinating neuronal activity among supporting cells, forming and maintaining the blood-brain barrier (BBB), and regulating neuroimmune responses. During ICH, NVU dysfunction is induced, along with neuronal cell death, microglia and astrocyte activation, endothelial cell (EC) and tight junction (TJ) protein damage, and BBB disruption. In addition, it has been shown that certain targets and candidates can improve ICH-induced secondary brain injury based on an NVU and neural-glia framework. Moreover, therapeutic approaches and strategies for ICH are discussed.

ETAR silencing ameliorated neurovascular injury after SAH in rats through ERK/KLF4-mediated phenotypic transformation of smooth muscle cells

Subarachnoid haemorrhage (SAH) is a devastating cerebrovascular disease which has a high morbidity and mortality. The phenotypic transformation of smooth muscle cells (SMCs) lead to neurovascular injury after SAH. However, the underlying mechanism remains unclear. In the present study, we aimed to investigate the potential role of ET-1/ET_AR on the phenotypic transformation of SMCs after SAH. The models of SAH were established in vivo and vitro. We observed ET-1 secretion by endothelial cells was increased, and the phenotypic transformation of SMCs was aggravated after SAH. Knocking down ET_AR inhibited the phenotypic transformation of SMCs, decreased the migration ability of SMCs in vitro. Moreover, Knocking down ET_AR ameliorated cerebral ischaemia and alleviated dysfunction of neurological function in vivo. In addition, Exogenous ET-1 increased the migration ability of SMCs and aggravated the phenotypic transformation of SMCs in vitro, which were partly reversed by the antagonist of Erk1/2 - SCH772984. Taken together, our results demonstrated that endothelial ET-1 aggravated the phenotypic transformation of SMCs after SAH. Knocking down ET_AR inhibited the phenotypic transformation of SMCs through ERK/KLF4 thus ameliorating neurovascular injury after SAH. We also revealed that ET-1/ET_AR is a potential therapeutic target after SAH.

SOCS1/JAK2/STAT3 axis regulates early brain injury induced by subarachnoid hemorrhage via inflammatory responses

The SOCS1/JAK2/STAT3 axis is strongly associated with tumor growth and progression, and participates in cytokine secretion in many diseases. However, the effects of the SOCS1/JAK2/STAT3 axis in experimental subarachnoid hemorrhage remain to be studied. A subarachnoid hemorrhage model was established in rats by infusing autologous blood into the optic chiasm pool. Some rats were first treated with JAK2/STAT3 small interfering RNA (Si-JAK2/Si-STAT3) or overexpression plasmids of JAK2/STAT3. In the brains of subarachnoid hemorrhage model rats, the expression levels of both JAK2 and STAT3 were upregulated and the expression of SOCS1 was downregulated, reaching a peak at 48 hours after injury. Simultaneously, the interactions between JAK2 and SOCS1 were reduced. In contrast, the interactions between JAK2 and STAT3 were markedly enhanced. Si-JAK2 and Si-STAT3 treatment alleviated cortical neuronal cell apoptosis and necrosis, destruction of the blood-brain barrier, brain edema, and cognitive functional impairment after subarachnoid hemorrhage. This was accompanied by decreased phosphorylation of JAK2 and STAT3 protein, decreased total levels of JAK2 and STAT3 protein, and increased SOCS1 protein expression. However, overexpression of JAK2 and STAT3 exerted opposite effects, aggravating subarachnoid hemorrhage-induced early brain injury. Si-JAK2 and Si-STAT3 inhibited M1-type microglial conversion and the release of pro-inflammatory factors (inducible nitric oxide synthase, interleukin-1β, and tumor necrosis factor-α) and increased the release of anti-inflammatory factors (arginase-1, interleukin-10, and interleukin-4). Furthermore, primary neurons stimulated with oxyhemoglobin were used to simulate subarachnoid hemorrhage in vitro, and the JAK2 inhibitor AG490 was used as an intervention. The in vitro results also suggested that neuronal protection is mediated by the inhibition of JAK2 and STAT3 expression. Together, our findings indicate that the SOCS1/JAK2/STAT3 axis contributes to early brain injury after subarachnoid hemorrhage both in vitro and in vivo by inducing inflammatory responses. This study was approved by the Animal Ethics Committee of Anhui Medical University and the First Affiliated Hospital of University of Science and Technology of China (approval No. LLSC-20180202) on March 1, 2018.

Neuroinflammation in hemorrhagic transformation after tissue plasminogen activator thrombolysis: Potential mechanisms, targets, therapeutic drugs and biomarkers

Hemorrhagic transformation (HT) is a common and serious complication following ischemic stroke, especially after tissue plasminogen activator (t-PA) thrombolysis, which is associated with increased mortality and disability. Due to the unknown mechanisms and targets of HT, there are no effective therapeutic drugs to decrease the incidence of HT. In recent years, many studies have found that neuroinflammation is closely related to the occurrence and development of HT after t-PA thrombolysis, including glial cell activation in the brain, peripheral inflammatory cell infiltration and the release of inflammatory factors, involving inflammation-related targets such as NF-κB, MAPK, HMGB1, TLR4 and NLRP3. Some drugs with anti-inflammatory activity have been shown to protect the BBB and reduce the risk of HT in preclinical experiments and clinical trials, including minocycline, fingolimod, tacrolimus, statins and some natural products. In addition, the changes in MMP-9, VAP-1, NLR, sICAM-1 and other inflammatory factors are closely related to the occurrence of HT, which may be potential biomarkers for the diagnosis and prognosis of HT. In this review, we summarize the potential inflammation-related mechanisms, targets, therapeutic drugs, and biomarkers associated with HT after t-PA thrombolysis and discuss the relationship between neuroinflammation and HT, which provides a reference for research on the mechanisms, prevention and treatment drugs, diagnosis and prognosis of HT.

Delayed Recanalization-How Late Is Not Too Late?

Stroke has become the second most prevalent cause of mortality in the world. Currently, the treatment of ischemic stroke is based on thrombolytic and thrombectomy therapy shortly after the ischemic event (≤ 4.5 h for thrombolytic strategies; ≤ 6 h for thrombectomy strategies). However, the majority of patients are unable to receive prompt treatment, particularly in undeveloped countries. Alternative solutions are lacking for those patients that miss the optimal window of opportunity for treatment. Recently, new developments in imaging techniques and intravascular interventional devices enable the expansion of the window of opportunity for treating stroke patients. Clinical studies have reported that delayed recanalization at 24 h, or even more than 1 month, was beneficial for some patients. However, the mechanisms of neuroprotection that underly the delayed recanalization in these ischemic stroke patients remain unclear. In this review, we will summarize the clinical studies of delayed recanalization, and organize them according to the duration of occlusion. Additionally, we will discuss the changing guidelines and possible mechanisms based on animal research, and attempt to draw conclusions and future perspectives.

MAPK: A Key Player in the Development and Progression of Stroke

Conclusion:

Stroke is a complex disease caused by genetic and environmental factors, and its etiological mechanism has not been fully clarified yet, which brings great challenges to its effective prevention and treatment. MAPK signaling pathway regulates gene expression of eukaryotic cells and basic cellular processes such as cell proliferation, differentiation, migration, metabolism and apoptosis, which are considered as therapeutic targets for many diseases. Up to now, mounting evidence has shown that MAPK signaling pathway is involved in the pathogenesis and development of ischemic stroke. However, the upstream kinase and downstream kinase of MAPK signaling pathway are complex and the influencing factors are numerous, the exact role of MAPK signaling pathway in the pathogenesis of ischemic stroke has not been fully elucidated. MAPK signaling molecules in different cell types in the brain respond variously after stroke injury, therefore, the present review article is committed to summarizing the pathological process of different cell types participating in stroke, discussed the mechanism of MAPK participating in stroke. We further elucidated that MAPK signaling pathway molecules can be used as therapeutic targets for stroke, thus promoting the prevention and treatment of stroke.

Acetyl-11-keto-β-boswellic acid prevents testicular torsion/detorsion injury in rats by modulating 5-LOX/LTB4 and p38-MAPK/JNK/Bax/Caspase-3 pathways

AIMS

Testicular torsion/detorsion (T/D) is a critical medical condition that necessitates prompt surgical intervention to avoid testicular atrophy and infertility. The use of natural compounds may protect against the associated detrimental oxidative stress and inflammatory responses. Interestingly, acetyl-11-keto-β-boswellic acid (AKBA), the main active constituent of Boswellia resin, has shown potent inhibitory effect on 5-lipoxygenase enzyme which converts arachidonic acid into inflammatory mediators. Therefore, this study was conducted to assess the protective mechanisms by which AKBA may protect against testicular T/D injury in rats.

MAIN METHODS

Male rats were randomly distributed into five groups: Sham, AKBA (50 mg/kg, p.o.), unilateral testicular T/D, AKBA at two dose levels (25 or 50 mg/kg for 15 successive days) followed by T/D. Histological examination and Johnsen's score were performed to assess testicular injury and perturbations in spermatogenesis. Biochemical parameters included markers of testicular function (serum testosterone), oxidant/antioxidant status (malondialdehyde, glutathione), inflammation (5-lipoxygenase, leukotriene-B4, myeloperoxidase, interleukin-1β, interleukin-6), apoptosis (Bax, Bcl2, caspase-3), DNA integrity (quantitative DNA fragmentation, DNA laddering, PARP-1), energy production (ATP), in addition to p38 MAPK and JNK protein expression.

KEY FINDINGS

In a dose dependent manner, AKBA significantly inhibited testicular T/D-induced upregulation of 5-LOX/LTB4 and p38-MAPK/JNK/Bax pathways and their associated downstream inflammatory and apoptotic cascades. These effects were accompanied with ATP replenishment and DNA preservation, resulting ultimately in salvage of the testis.

SIGNIFICANCE

Unprecedentedly, the present mechanistic study revealed the pathways by which AKBA may inhibit testicular T/D injury and offered a novel protective approach that may attenuate the severity of this condition.

Relevance of Porcine Stroke Models to Bridge the Gap from Pre-Clinical Findings to Clinical Implementation

In the search of animal stroke models providing translational advantages for biomedical research, pigs are large mammals with interesting brain characteristics and wide social acceptance. Compared to rodents, pigs have human-like highly gyrencephalic brains. In addition, increasingly through phylogeny, animals have more sophisticated white matter connectivity; thus, ratios of white-to-gray matter in humans and pigs are higher than in rodents. Swine models provide the opportunity to study the effect of stroke with emphasis on white matter damage and neuroanatomical changes in connectivity, and their pathophysiological correlate. In addition, the subarachnoid space surrounding the swine brain resembles that of humans. This allows the accumulation of blood and clots in subarachnoid hemorrhage models mimicking the clinical condition. The clot accumulation has been reported to mediate pathological mechanisms known to contribute to infarct progression and final damage in stroke patients. Importantly, swine allows trustworthy tracking of brain damage evolution using the same non-invasive multimodal imaging sequences used in the clinical practice. Moreover, several models of comorbidities and pathologies usually found in stroke patients have recently been established in swine. We review here ischemic and hemorrhagic stroke models reported so far in pigs. The advantages and limitations of each model are also discussed.

The Activation of Phosphatidylserine/CD36/TGF-β1 Pathway prior to Surgical Brain Injury Attenuates Neuroinflammation in Rats

Neuroinflammation plays an important pathological role in experimental surgical brain injury (SBI). Apoptotic associated with phosphatidylserine (PS) externalization promotes anti-inflammatory mediator TGF-β1 release. In the present study, we investigated the anti-neuroinflammation effect of PS liposome or isoflurane pretreatment via PS/CD36/TGF-β1 signaling in a rat model of SBI. A total of 120 male Sprague-Dawley rats (weighing 280-330 gms) were used. SBI was induced by partial right frontal lobe corticotomy. Intranasal PS liposome or isoflurane inhalation was administered prior to SBI induction. CD36 small interfering RNA (siRNA) was administered intracerebroventricularly. Recombinant Annexin V protein (rAnnexin V) was delivered intranasally. Post-SBI assessments included neurological tests, brain water content, Western blot, and immunohistochemistry. Endogenous CD36 protein levels but not TGF-β1 was significantly increased within peri-resection brain tissues over 72 h after SBI. SBI rats were associated with increased brain water content surrounding corticotomy and neurological deficits. PS liposome pretreatment significantly reduced brain water content and improved some neurological deficits at 24 hours and 72 hours after SBI. PS liposome increased CD36 and TGF-β1 protein levels, but decreased IL-1β and TNFα protein levels in peri-resection brain tissues at 24 hours after SBI. CD36 siRNA or rAnnexin V partially countered the protective effect of PS liposome. Isoflurane pretreatment produced similar antineuroinflammation and neurological benefits in SBI rats partially by upregulating CD36/Lyn/TGF-β1 signaling. Collectively, our findings suggest that the activation of PS/CD36/TGF-β1 pathway by PS liposome or isoflurane prior to SBI could attenuate neuroinflammation and improve neurological outcomes in rats. PS liposome or isoflurane pretreatment may serve as an effective preventive strategy to minimize the brain injury caused by neurosurgical procedures in patients.

Neuroinflammation and fibrosis in stroke: The good, the bad and the ugly

Stroke is the leading cause of death and the main cause of disability in surviving patients. The detrimental interaction between immune cells, glial cells, and matrix components in stroke pathology results in persistent inflammation that progresses to fibrosis. A substantial effort is being directed toward understanding the exact neuroinflammatory events that take place as a result of stroke. The initiation of a potent cytokine response, along with immune cell activation and infiltration in the ischemic core, has massive acute deleterious effects, generally exacerbated by comorbid inflammatory conditions. There is secondary neuroinflammation that promotes further injury, resulting in cell death, but conversely plays a beneficial role, by promoting recovery. This highlights the need for a better understanding of the neuroinflammatory and fibrotic processes, as well as the need to identify new mechanisms and potential modulators. In this review, we summarize several aspects of stroke-induced inflammation, fibrosis, and include a discussion of cytokine inhibitors/inducers, immune cells, and fibro-inflammation signaling inhibitors in order to identify new pharmacological means of intervention.

Miro1 Regulates Neuronal Mitochondrial Transport and Distribution to Alleviate Neuronal Damage in Secondary Brain Injury After Intracerebral Hemorrhage in Rats

Intracerebral hemorrhage (ICH) is a primary cause of death and disability in adults worldwide. Secondary brain injury (SBI) induced by ICH can lead to impaired mitochondrial function, which ultimately contributes to apoptosis and necrosis. Mitochondrial Rho GTPase 1 (Miro1) is a key regulator of mitochondrial movement and motor protein binding. Although Miro1 has been demonstrated to be implicated in various types of central nervous system damage, its potential effect on ICH-induced SBI has not been studied in detail. Hence, in the present new study, we explored the effect of Miro1 on SBI in vivo and in vitro. Self-body heart blood was injected into the right basal ganglia of the rat brain in vivo. Meanwhile, our in vitro model of ICH was based on the stimulation of oxygen hemoglobin (OxyHb) to neurons. Then, Miro1 was overexpressed both in the brains of rats after ICH in vivo and in OxyHb-treated cultured neurons in vitro. Miro1 overexpression in vivo reduced several pathological indexes such as brain edema, neurobehavioral impairment, and neuronal death. Immunofluorescent staining in vitro showed that overexpression of Miro1 ameliorated neuronal damage via facilitation of mitochondrial transport and distribution. JC-1 staining indicated that overexpression of Miro1 reduced the collapse of mitochondrial membrane potential and enhanced mitochondrial mass. Additionally, live-dead cellular staining and flow cytometry analysis revealed that Miro1 overexpression in cultured neurons reduced both necrotic and apoptotic rates. In contrast, inhibition of Miro1 expression yielded opposite effects to those of Miro1 overexpression. Above all, the upregulation of Miro1 significantly alleviated pathological symptoms on SBI in vivo and in vitro.

Divergence and Convergence of Cerebral Ischemia Pathways Profile Deciphers Differential Pure Additive and Synergistic Mechanisms

Aim

The variable mechanisms on additive and synergistic effects of jasminoidin (JA)-Baicalin (BA) combination and JA-ursodeoxycholic acid (UA) combination in treating cerebral ischemia are not completely understood. In this study, we explored the differential pure mechanisms of additive and synergistic effects based on pathway analysis that excluded ineffective interference.

Methods

The MCAO mice were divided into eight groups: sham, vehicle, BA, JA, UA, Concha Margaritifera (CM), BA-JA combination (BJ), and JA-UA combination (JU). The additive and synergistic effects of combination groups were identified by cerebral infarct volume calculation. The differentially expressed genes based on a microarray chip containing 16,463 oligoclones were uploaded to GeneGo MetaCore software for pathway analyses and function catalogue. The comparison of specific pathways and functions crosstalk between different groups were analyzed to reveal the underlying additive and synergistic pharmacological variations.

Results

Additive BJ and synergistic JU were more effective than monotherapies of BA, JA, and UA, while CM was ineffective. Compared with monotherapies, 43 pathways and six functions were found uniquely in BJ group, with 33 pathways and three functions in JU group. We found six overlapping pathways and six overlapping functions between BJ and JU groups, which mainly involved central nervous system development. Thirty-seven specific pathways and 10 functions were activated by additive BJ, which were mainly related to cell adhesion and G-protein signaling; and 27 specific pathways and three functions of synergistic JU were associated with regulation of metabolism, DNA damage, and translation. The overlapping and distinct pathways and functions may contribute to different additive and synergistic effects.

Conclusion

The divergence pathways of pure additive effect of BJ were mainly related to cell adhesion and G-protein signaling, while the pure synergistic mechanism of JU depended on metabolism, translation and DNA damage. Such a systematic analysis of pathways may provide an important paradigm to reveal the pharmacological mechanisms underlying drug combinations.

NLRP3 Inflammasome in the Pathophysiology of Hemorrhagic Stroke: A Review

Hemorrhagic stroke is a devastating disease with high morbidity and mortality. There is still a lack of effective ther-apeutic approach. The recent studies have shown that the innate immune system plays a significant role in hemorrhagic stroke. Microglia, as major components in innate immune system, are activated and then can release cytokines and chemo-kines in response to hemorrhagic stroke, and ultimately led to neuroinflammation and brain injury. The NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome is predominantly released by microglia and is believed as the main contributor of neuroinflammation. Several studies have focused on the role of NLRP3 inflammasome in hemorrhagic stroke-induced brain injury, however, the specific mechanism of NLRP3 activation and regulation remains unclear. This re-view summarized the mechanism of NLRP3 activation and its role in hemorrhagic stroke and discussed the translational sig-nificance.

The potential role of inflammation in cryptogenic stroke

PURPOSE

The study aimed to identify biomarkers predictive of cryptogenic stroke in patients aged <65.

MATERIALS AND METHODS

We investigated 520 patients with ischemic stroke. Out of them we assigned 65 patients to the cryptogenic stroke group (age 54 (47-58), 42% male) and 36 without stroke to the control group (age 53 (47-58), 61% male). In all patients we assessed carotid intima-media thickness (cIMT) and the levels of biomarkers which might be involved in the underlying biological mechanism of ischemic stroke.

RESULTS

There were no differences between stroke and control groups in the levels of syndecan 4, resistin, leptin, low-density lipoprotein cholesterol, triglycerides, prothrombin time, or activated partial thromboplastin time. There was no statistically significant difference in cIMT between groups. The level of high-density lipoprotein cholesterol was statistically significantly lower in the cryptogenic stroke group than in the controls (1.1 mmol/L (0.95-1.46) vs 1.37 (1.19-1.6) p = 0.02). Patients in the stroke group had higher levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) (391 pg/ml (107-1249) vs 109 (46-236); p = 0.003), interleukin 6 (2.6 pg/ml (0.8-8.1) vs 0.7 (0.4-1.2) p = 0.002) and asymmetric dimethylarginine (ADMA) (0.44 μmol/L (0.39-0.55) vs 0.36 (0.32-0.4); p = 0.0002) than the control group. In the multivariate analysis Il-6 was the only biomarker statistically significant associated with the occurrence of cryptogenic stroke (odds ratio 1.918, 95% confidence interval 1.029-3.575; p = 0.04).

CONCLUSIONS

Endothelial dysfunction assessed by increased level of ADMA affects the inflammatory state in patients with cryptogenic stroke. Increase in the inflammatory cytokine IL-6 by 1 pg/ml almost doubles the risk of stroke.

Global brain inflammation in stroke

Stroke, including acute ischaemic stroke and intracerebral haemorrhage, results in neuronal cell death and the release of factors such as damage-associated molecular patterns (DAMPs) that elicit localised inflammation in the injured brain region. Such focal brain inflammation aggravates secondary brain injury by exacerbating blood-brain barrier damage, microvascular failure, brain oedema, oxidative stress, and by directly inducing neuronal cell death. In addition to inflammation localised to the injured brain region, a growing body of evidence suggests that inflammatory responses after a stroke occur and persist throughout the entire brain. Global brain inflammation might continuously shape the evolving pathology after a stroke and affect the patients' long-term neurological outcome. Future efforts towards understanding the mechanisms governing the emergence of so-called global brain inflammation would facilitate modulation of this inflammation as a potential therapeutic strategy for stroke.

Neuroprotective effects of neurotropin in a mouse model of hypoxic-ischemic brain injury

PURPOSE

Ischemic-hypoxic insult leads to detrimental effects on multiple organs. The brain is especially vulnerable, and it is hard to regenerate once damaged. Currently, therapeutic options are very limited. Previous studies have reported neuroprotective effects of neurotropin, a non-protein extract derived from the inflamed skin of rabbits inoculated with vaccinia virus, using a murine model of peripheral nerve injury and cultured cell lines. However, whether neurotropin might have protective effects against brain injuries remains unclear. We, therefore, investigated the neuroprotective effect of neurotropin and possible underlying mechanisms, using a mouse model of hypoxic-ischemic brain injury.

METHODS

Hypoxic-ischemic brain injury was induced via a combination of the left common carotid artery occlusion and exposure to hypoxic environment (8% oxygen) in adult male C57BL/6 mice. Immediately following induction of hypoxia-ischemia, mice received either saline or 2.4 units of neurotropin. The survival rate, neurological function, infarct volume, and expression of inflammatory cytokines were evaluated.

RESULTS

Compared to the control group, the neurotropin group exhibited a significantly higher survival rate (100% vs. 62.5%, p < 0.05) and lower neurological deficit scores (1; 0-2 vs. 3; 0-5, median; range, p < 0.05) after the hypoxic-ischemic insult. The administration of neurotropin also reduced infarct volume (18.3 ± 5.1% vs. 38.3 ± 7.2%, p < 0.05) and mRNA expression of pro-inflammatory cytokines.

CONCLUSIONS

The post-treatment with neurotropin improved survival and neurological outcomes after hypoxic-ischemic insult. Our results indicate that neurotropin has neuroprotective effects against hypoxic-ischemic brain injury by suppressing pro-inflammatory cytokines.

Kinesin-1 Regulates Extrasynaptic Targeting of NMDARs and Neuronal Vulnerability Toward Excitotoxicity

N-methyl-D-aspartate (NMDA) receptor (NMDAR) is highly compartmentalized in neurons, and its dysfunction has been implicated in various neuropsychiatric and neurodegenerative disorders. Recent failure to exploit NMDAR antagonization as a potential therapeutic target has driven the need to identify molecular mechanisms that regulate NMDAR compartmentalization. Here, we report that the reduction of Kif5b, the heavy chain of kinesin-1, protected neurons against NMDA-induced excitotoxicity and ischemia-provoked neurodegeneration. Direct binding of kinesin-1 to the GluN2B cytoplasmic tails regulated the levels of NMDAR at extrasynaptic sites and the subsequent influx of calcium mediated by extrasynaptic NMDAR by regulating the insertion of NMDARs into neuronal surface. Transient increase of Kif5b restored the surface levels of NMDAR and the decreased neuronal susceptibility to NMDA-induced excitotoxicity. The expression of Kif5b was repressed in cerebral ischemia preconditioning. Our findings reveal that kinesin-1 regulates extrasynaptic NMDAR targeting and signaling, and the reduction of kinesin-1 could be exploited to defer neurodegeneration.

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Kif5b directly binds with GluN2B-containing NMDAR

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Kinesin-1 mediates extrasynaptic NMDAR targeting and function

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Reduction of kinesin-1 protects neurons against NMDAR-elicited excitotoxicity

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Reduction of kinesin-1 protects brain against ischemia-elicited neurodegeneration

Compromised Dynamic Cerebral Autoregulation in Patients With Depression

Background: Patients with depression tend to have various comorbid neurological symptoms, but the mechanisms remain unclear. The purpose of this study was to analyze the characteristics of dynamic cerebral autoregulation in depressed patients. Methods: Patients (aged ≥ 18 years) who were diagnosed with depression [17-item Hamilton Depression Rating Scale (HAMD) > 17] or suspected of depression (HAMD > 7) were enrolled in this study. Medically healthy volunteers were recruited as controls. The subjects also received the 7-item HAMD. We simultaneously recorded noninvasive continuous arterial blood pressure and bilateral middle cerebral artery blood flow velocity from each subject. Cerebral autoregulation was assessed by analyzing the phase difference using transfer function analysis. Results: This study enrolled 54 patients with suspected depression, 45 patients with depression, and 48 healthy volunteers. The mean phase difference values were significantly lower in the patients with depression (F = 9.071, P < 0.001). In the multiple regression analysis, depression was negatively correlated with the phase difference values. Conclusions: Dynamic cerebral autoregulation was compromised in patients with depression and negatively correlated with the depression score. Improving dynamic cerebral autoregulation may be a potential therapeutic method for treating the neurological symptoms of depression.

Antioxidant Melatonin: Potential Functions in Improving Cerebral Autoregulation After Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is a subtype of stroke with high mortality and morbidity. Impaired cerebral autoregulation following SAH has been reported owing to effects on sympathetic control, endothelial function, myogenic response, and cerebral metabolism. Impaired cerebral autoregulation is associated with early brain injury, cerebral vasospasm/delayed cerebral ischemia, and SAH prognosis. However, few drugs have been reported to improve cerebral autoregulation after SAH. Melatonin is a powerful antioxidant that is effective (easily crosses the blood brain barrier) and safe (tolerated in large doses without toxicity). Theoretically, melatonin may impact the control mechanisms of cerebral autoregulation via antioxidative effects, protection of endothelial cell integrity, suppression of sympathetic nerve activity, increase in nitric oxide bioavailability, mediation of the myogenic response, and amelioration of hypoxemia. Furthermore, melatonin may have a comprehensive effect on cerebral autoregulation. This review discusses the potential effects of melatonin on cerebral autoregulation following SAH, in terms of the association between pharmacological activities and the mechanisms of cerebral autoregulation.