The cost of cerebral ischaemia

Implementing strategy training in Taiwan: perspectives of individuals with Acquired brain injury

PURPOSE

Strategy training is a rehabilitation intervention that aims to enhance problem-solving skills with respect to daily activity-related challenges and has achieved favorable results in Western countries. This study explored the perspectives of individuals with acquired brain injury (ABI) in Taiwan who received strategy training.

MATERIALS AND METHODS

Semi-structured interviews with community-dwelling adults with ABI were conducted, and reflective memos made by research team members were recorded. Interviews and memos were analyzed through thematic analysis.

RESULTS

This study included 55 participants. The analysis of the participants' interview responses and memos yielded nine themes under three categories: 1) expectations regarding strategy training, 2) perceived benefits of strategy training, and 3) barriers affecting the process and outcomes of strategy training.

CONCLUSIONS

All the participants endorsed strategy training through different gains. Most participants' expectations before the intervention were uncertain. Including family members into the strategy training is of key importance for a successfulness of their goals. The participants' experiences about strategy training were affected by various barriers (i.e., health and medical problems, the physical environment, and natural events). Clinicians and researchers should consider these expectations, benefits, and barriers when studying and implementing strategy training in non-Western contexts.IMPLICATIONS FOR REHABILITATIONStrategy training provides clients the opportunity to actively engage in their own goal setting and decision making.Strategy training increases the client's confidence in their ability to participate in the community, communicate, and perform daily living and physical activities.Therapists should consider the health conditions and physical environment of clients when helping them set goals and before facilitating their engagement in the community.Taiwanese family members play a crucial role in supporting acquired brain injury survivors in strategy training.

Dapoxetine prevents neuronal damage and improves functional outcomes in a model of ischemic stroke through the modulation of inflammation and oxidative stress

Stroke is a medical emergency that is associated with substantial mortality and functional disability in adults. The most popular class of antidepressants, selective serotonin reuptake inhibitors SSRIs, have recently been shown in studies to have positive effects on post-stroke motor and cognitive function. Thus, we hypothesized that dapoxetine (DAP), a short-acting SSRI, would be effective against cerebral ischemia/reperfusion injury. Adult male Wister rats (200-250 g) were subjected to a sham operation or bilateral common carotid artery occlusion (BCCAO) for 30 min followed by 24 h of reperfusion to induce global cerebral ischemia/reperfusion (I/R) injury. Rats were treated with vehicle or DAP (30 or 60 mg/kg, i.p.) 1 h before BCCAO. The neurobehavioral performance of rats was assessed. The infarct volume, histopathological changes, oxidative stress parameters, and apoptotic and inflammatory mediators were determined in the brain tissues of euthanized rats. Our results confirmed that DAP significantly ameliorated cerebral I/R-induced neurobehavioral deficits, reduced cerebral infarct volume, and histopathological damage. Moreover, DAP pretreatment reduced lipid peroxidation, caspase-3, and inflammatory mediators (TNF-α and iNOS) compared to I/R-injured rats. Thus, DAP pretreatment potentially improves neurological function, and cerebral damage in cerebral ischemic rats may be partly related to the reduction in the inflammatory response, preservation of oxidative balance, and suppression of cell apoptosis in brain tissues.

Increasing of Cortisol Level and Neutrophil-Lymphocyte-Ratio are Associated with Severity Level and Sleep Disturbances in Acute Ischemic Stroke

Background

Acute ischemic stroke can cause sleep disturbances. These complaints involve various factors, such as disturbances of the hormone cortisol and Neutrophil-Lymphocyte-Ratio (NLR) that can cause increasing severity levels in acute ischemic stroke patients. This study aimed to determine the relationship between cortisol levels and NLR with severity levels and sleep disturbances in acute ischemic stroke patients.

Methods

A cross-sectional analytic observational study was conducted on acute ischemic stroke patients during Agustus - December 2022. Examine cortisol levels using the ELISA method, NLR from blood test, asses severity levels using the National Institute of Health Stroke Scale (NIHSS), and The Pittsburgh Sleep Questionnaire Index (PSQI) is used as a measure for the initial screening of sleep disturbances-statistical analysis using Spearman correlation.

Results

Total study subjects were 48 patients, with the majority 62.5% women; the mean age of study subjects was above 60 years (56.3%), and the most common type of stroke was large artery atherosclerotic stroke (77.1%), the highest NIHSS score was in the moderate category (85.4%), the most common risk factor is hypertension (64.4%), and basal ganglia area is the most common ischemic stroke location (52.1%). There was a positive correlation between cortisol levels with NIHSS (r=0.874; p-value <0.001), NLR with sleep disturbances (r=0.829; p-value<0.001), NLR with NIHSS (r=0.893; p-value<0.001), and NIHSS with PSQI (r=0.836; p-value<0.001).

Conclusion

There were a positive correlation between cortisol level, NLR level, and NIHSS score with sleep quality disturbances based on PSQI in acute ischemic stroke patients.

Applications of Induced Pluripotent Stem Cell-Derived Glia in Brain Disease Research and Treatment

Glia are integral components of neural networks and are crucial in both physiological functions and pathological processes of the brain. Many brain diseases involve glial abnormalities, including inflammatory changes, mitochondrial damage, calcium signaling disturbance, hemichannel opening, and loss of glutamate transporters. Induced pluripotent stem cell (iPSC)-derived glia provide opportunities to study the contributions of glia in human brain diseases. These cells have been used for human disease modeling as well as generating new therapies. This chapter introduces glial involvement in brain diseases, then summarizes different methods of generating iPSC-derived glia disease models of these cells. Finally, strategies for treating disease using iPSC-derived glia are discussed. The goal of this chapter is to provide an overview and shed light on the applications of iPSC-derived glia in brain disease research and treatment.

Access to acute stroke care: A retrospective descriptive analysis of stroke patients' journey to a district hospital

Introduction

The burden of stroke in Africa has increased in the last two decades, with the population undergoing a rapid epidemiological transition, with a rise in the incidence of stroke risk factors together with the gradual aging of the population. Evidence-based guidelines for acute stroke care are often not feasible in resource challenged settings but even when resources are available, considerable delays to definitive care exists. This study aims to describe the factors that influence time from symptom onset to hospital arrival in patients that present to a district level hospital Emergency Centre with confirmed ischaemic strokes.

Methods

A descriptive analysis was performed using a retrospective folder and database review. All adult patients with a confirmed ischaemic stroke, on Computed Tomography (CT) scan, presenting to Mitchells Plain Hospital Emergency Centre during the study period of 12 months (1^st of January 2019 to 31^st of December 2019), were eligible for inclusion. Data were collected from existing electronic patient databases and the time from onset of symptoms to hospital arrival was extracted from the clinical notes.

Results

A total of 730 (2%) patients presented with a diagnosis of stroke, of which 381 (52%) were included (CT confirmed ischaemic strokes). Only 48 (13%) presented within 4.5 h of symptom onset and the median time from onset of symptoms to presentation to the hospital was 24 h (IQR 12-72 h). The majority of patients (31%) arrived via a primary public emergency medical service (EMS) call, while 29% presented directly to the hospital as self-referrals with private transport. Primary public EMS calls had the shortest call-to-hospital-arrival time (1 hour and 31 minutes), even though the median time from symptom onset to hospital arrival was still 16 h.

Conclusion

The median time from symptom onset to hospital arrival for patients with stroke symptoms is much longer than what evidence-based guidelines suggest. The chain of survival for emergency stroke care is only as strong as its weakest link and the data from this study suggest that improvement campaigns should target stroke education and access to care.

Delivering the Promise of Gene Therapy with Nanomedicines in Treating Central Nervous System Diseases

Central Nervous System (CNS) diseases, such as Alzheimer's diseases (AD), Parkinson's Diseases (PD), brain tumors, Huntington's disease (HD), and stroke, still remain difficult to treat by the conventional molecular drugs. In recent years, various gene therapies have come into the spotlight as versatile therapeutics providing the potential to prevent and treat these diseases. Despite the significant progress that has undoubtedly been achieved in terms of the design and modification of genetic modulators with desired potency and minimized unwanted immune responses, the efficient and safe in vivo delivery of gene therapies still poses major translational challenges. Various non-viral nanomedicines have been recently explored to circumvent this limitation. In this review, an overview of gene therapies for CNS diseases is provided and describes recent advances in the development of nanomedicines, including their unique characteristics, chemical modifications, bioconjugations, and the specific applications that those nanomedicines are harnessed to deliver gene therapies.

HMGA2 Promotes Brain Injury in Rats with Cerebral Infarction by Activating TLR4/NF-κB Signaling Pathway

Cerebral infarction is a common disease with a higher disability and fatality rates. The incidence rates of cerebral infarction or cerebral ischemic stroke gradually increase with aging and cerebrovascular disease progression. This study is aimed at evaluating the effects of HMGA2 on cerebral infarction-induced brain tissue damage and its underlying mechanisms. Adult Sprague Dawley rats were pretreated with sh-HMGA2 before cerebral infarction operation. The effect of HMGA2 on the arrangement, distribution, and morphological structure of neurons and the cell apoptosis ratio in brain tissue were detected via hematoxylin and eosin staining, brain-water content, TTC staining, and TUNEL staining. The results from ELISA assay, qPCR, and western blot indicated that downregulation of HMGA2 mitigated inflammatory stress via regulating the expression of TLR4/NF-κB. In addition, results showed that suppressed HMGA2 attenuated the neurological dysfunction of brain injury rats and markedly reduced infarct volume. HMGA2 might be able to alleviate the damage associated with cerebral infarction-induced inflammatory response and cell apoptosis. Moreover, downregulation of HMGA2 had a protective effect on the brain damage derived from cerebral infarction by mediating the TLR4/NF-κB pathway. In conclusion, the current study demonstrated that downregulation of HMGB2 decreased the infarct size, inflammatory responses, and apoptosis in cerebral injury and further had neuroprotective effects against cerebral infarction-induced brain damage. Finally, these results indicated that the downregulation of the TLR4/NF-κB pathway after ischemia by HMGB2 inhibition is a potential mechanism of the neuroprotective effect of cerebral injury.

Therapeutic implications of glucose transporters (GLUT) in cerebral ischemia

Cerebral ischemia is a leading cause of death in the globe, with a large societal cost. Deprivation of blood flow, together with consequent glucose and oxygen shortage, activates a variety of pathways that result in permanent brain damage. As a result, ischemia raises energy demand, which is linked to significant alterations in brain energy metabolism. Even at the low glucose levels reported in plasma during ischemia, glucose transport activity may adjust to assure the supply of glucose to maintain normal cellular function. Glucose transporters in the brain are divided into two groups: sodium-independent glucose transporters (GLUTs) and sodium-dependent glucose cotransporters (SGLTs).This review assess the GLUT structure, expression, regulation, pathobiology of GLUT in cerebral ischemia and regulators of GLUT and it also provides the synopsis of the literature exploring the relationship between GLUT and the various downstream signalling pathways for e.g., AMP-activated protein kinase (AMPK), CREB (cAMP response element-binding protein), Hypoxia-inducible factor 1 (HIF)-1, Phosphatidylinositol 3-kinase (PI3-K), Mitogen-activated protein kinase (MAPK) and adenylate-uridylate-rich elements (AREs). Therefore, the aim of the present review was to elaborate the therapeutic implications of GLUT in the cerebral ischemia.

Personalised Approach to Diagnosing and Managing Ischemic Stroke with a Plasma-Soluble Urokinase-Type Plasminogen Activator Receptor

Background: The increasing incidence of ischemic stroke has led to the search for a novel biomarker to predict the course of disease and the risk of mortality. Recently, the role of the soluble urokinase plasminogen activator receptor (suPAR) as a biomarker and indicator of immune system activation has been widely examined. Therefore, the aim of the current study was to assess the dynamics of changes in serum levels of suPAR in ischemic stroke and to evaluate the prognostic value of suPAR in determining mortality risk. Methods: Eighty patients from the Department of Neurology, diagnosed with ischemic stroke, were enrolled in the study. Residual blood was obtained from all the patients on the first, third and seventh days after their ischemic stroke and the concentrations of suPAR and C-reactive protein (CRP), as well as the number of leukocytes and National Institute of Health’s Stroke Scale (NIHSS) scores, were evaluated. Results: On the first day of ischemic stroke, the average suPAR concentration was 6.55 ng/mL; on the third day, it was 8.29 ng/mL; on the seventh day, it was 9.16 ng/mL. The average CRP concentration on the first day of ischemic stroke was 4.96 mg/L; on the third day, it was 11.76 mg/L; on the seventh day, it was 17.17 mg/L. The number of leukocytes on the first day of ischemic stroke was 7.32 × 103/mm3; on the third day, it was 9.27 × 103/mm3; on the seventh day, it was 10.41 × 103/mm3. Neurological condition, which was assessed via the NIHSS, on the first day of ischemic stroke, was scored at 10.71 points; on the third day, it was scored at 12.34 points; on the seventh day, it was scored at 13.75 points. An increase in the values of all the evaluated parameters on the first, third and seventh days of hospitalisation was observed. The patients with hypertension, ischemic heart disease and type 2 diabetes showed higher suPAR and CRP concentrations at the baseline as well as on subsequent days of hospitalisation. The greatest sensitivity and specificity were characterised by suPAR-3, where a value above 10.5 ng/mL resulted in a significant increase in mortality risk. Moreover, an NIHSS-1 score above 12 points and a CRP-3 concentration above 15.6 mg/L significantly increased the risk of death in the course of the disease. Conclusions: The plasma suPAR concentration after ischemic stroke is strongly related to the patient’s clinical status, with a higher concentration on the first and third days of stroke resulting in a poorer prognosis at a later stage of treatment. Therefore, assessing the concentration of this parameter has important prognostic value.

Improving Awareness Could Transform Outcomes in Degenerative Cervical Myelopathy [AO Spine RECODE-DCM Research Priority Number 1]

STUDY DESIGN

Literature Review (Narrative).

OBJECTIVE

To introduce the number one research priority for Degenerative Cervical Myelopathy (DCM): Raising Awareness.

METHODS

Raising awareness has been recognized by AO Spine RECODE-DCM as the number one research priority. This article reviews the evidence that awareness is low, the potential drivers, and why this must be addressed. Case studies of success from other diseases are also reviewed, drawing potential parallels and opportunities for DCM.

RESULTS

DCM may affect as many as 1 in 50 adults, yet few will receive a diagnosis and those that do will wait many years for it. This leads to poorer outcomes from surgery and greater disability. DCM is rarely featured in healthcare professional training programs and has received relatively little research funding (<2% of Amyotrophic Lateral Sclerosis or Multiple Sclerosis over the last 25 years). The transformation of stroke and acute coronary syndrome services, from a position of best supportive care with occasional surgery over 50 years ago, to avoidable disability today, represents transferable examples of success and potential opportunities for DCM. Central to this is raising awareness.

CONCLUSION

Despite the devastating burden on the patient, recognition across research, clinical practice, and healthcare policy are limited. DCM represents a significant unmet need that must become an international public health priority.

Senkyunolide H protects PC12 cells from OGD/R-induced injury via cAMP-PI3K/AKT signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Senkyunolide H (SNH) is a bioactive phthalide isolated from Ligusticum chuanxiong Hort rhizome and was reported to have multiple pharmacological effects.

AIM OF THE STUDY

The study was performed to verify the potency of SNH protecting PC12 cells from oxygen glucose deprivation/reperfusion (OGD/R)-induced injury and to elucidate the underlying mechanisms.

MATERIALS AND METHODS

OGD/R model was established in PC12 cells and the cell viability was measured by MTT assay. The cell morphology was observed using scanning electron microscope (SEM). The potential targets of SNH and related targets of OGD/R were screened, and a merged protein-protein interaction (PPI) network of SNH and OGD/R was constructed based on the network pharmacology analysis. Kyoto Encyclopedia of Genes and Genomes (KEGG) database was used for pathway analysis. Intracellular cAMP level and the protein expression levels were measured to elucidate the underlying mechanisms.

RESULTS

SNH pretreatment protected PC12 cells against OGD/R-induced cell death. SNH also significantly protected the cell protrusion. A merged PPI network was constructed and the shared candidate targets significantly enriched in cAMP signaling pathway. The level of intracellular cAMP and the protein level of p-CREB, p-AKT, p-PDK1 and PKA protein were up-regulated after the treatment of SNH compared with OGD/R modeling.

CONCLUSIONS

The present study indicated that SNH protected PC12 cells from OGD/R-induced injury via cAMP-PI3K/AKT signaling pathway.

Therapeutic Potential of Astrocyte Transplantation

Cell transplantation is an attractive treatment strategy for a variety of brain disorders, as it promises to replenish lost functions and rejuvenate the brain. In particular, transplantation of astrocytes has come into light recently as a therapy for amyotrophic lateral sclerosis (ALS); moreover, grafting of astrocytes also showed positive results in models of other conditions ranging from neurodegenerative diseases of older age to traumatic injury and stroke. Despite clear differences in etiology, disorders such as ALS, Parkinson's, Alzheimer's, and Huntington's diseases, as well as traumatic injury and stroke, converge on a number of underlying astrocytic abnormalities, which include inflammatory changes, mitochondrial damage, calcium signaling disturbance, hemichannel opening, and loss of glutamate transporters. In this review, we examine these convergent pathways leading to astrocyte dysfunction, and explore the existing evidence for a therapeutic potential of transplantation of healthy astrocytes in various models. Existing literature presents a wide variety of methods to generate astrocytes, or relevant precursor cells, for subsequent transplantation, while described outcomes of this type of treatment also differ between studies. We take technical differences between methodologies into account to understand the variability of therapeutic benefits, or lack thereof, at a deeper level. We conclude by discussing some key requirements of an astrocyte graft that would be most suitable for clinical applications.

The 5-HT1A receptor as a serotonergic target for neuroprotection in cerebral ischemia

Cerebral ischemia due to stroke or cardiac arrest greatly affects daily functioning and the quality of life of patients and has a high socioeconomic impact due to the surge in their prevalence. Advances in the identification of an effective pharmacotherapy to promote neuroprotection and recovery after a cerebral ischemic insult are, however, limited. The serotonin 1A (5-HT_1A) receptor has been implicated in the regulation of several brain functions, including mood, emotions, memory, and neuroplasticity, all of which are deleteriously affected by cerebral ischemia. This review focuses on the specific roles and mechanisms of 5-HT_1A receptors in neuroprotection in experimental models of cerebral ischemia. We present experimental evidence that 5-HT_1A receptor agonists can prevent neuronal damage and promote functional recovery induced by focal and transient global ischemia in rodents. However, indiscriminate activation of pre-and postsynaptic by non-biased 5-HT_1A receptor agonists may be a limiting factor in the anti-ischemic clinical efficacy of these compounds since 5-HT_1A receptors in different brain regions can mediate diverging or even contradictory responses. Current insights are presented into the 'biased' 5-HT_1A post-synaptic heteroreceptor agonist NLX-101 (also known as F15599), a compound that preferentially and potently stimulates postsynaptic cortical pyramidal neurons without inhibiting firing of serotoninergic neurons, as a potential strategy providing neuroprotection in cerebral ischemic conditions.

Enhancing community participation for stroke survivors with cognitive impairment: study protocol for a randomised controlled trial in Taiwan

INTRODUCTION

Stroke can lead to life-long disability and constitutes a huge financial burden on the family and society. Stroke survivors with cognitive impairment often experience considerable challenges in the process of recovery and returning to society. Interventions that effectively help individuals resume essential daily activities and return to active participation in their communities are lacking. This study examines the efficacy of a newly-developed intervention programme, the Optimising Participation after Stroke through Strategy-training (OPASS) programme, for improving community participation among stroke survivors with cognitive impairment.

METHODS AND ANALYSIS

A single-blind, parallel-group randomised controlled trial with allocation concealment and assessor blinding will be implemented to assess the efficacy of the OPASS programme. An expected 210 adults with cognitive impairment following stroke will be randomly assigned to either the experimental intervention (OPASS) group or the attention control group. In addition to their usual rehabilitation, both groups will receive 45 min sessions, twice weekly for a total of 12-15 sessions. The primary outcome is change in participation performance, which will be measured using the participation measure-three domains, four dimensions scale. Additional measures include the Activity Measure for Post-Acute Care generic outpatient short forms, Montreal Cognitive Assessment, Stroop Test, Trail Making Test and General Self-Efficacy Scale. These scales will be administered at baseline, post-intervention, 3-month follow-up, 6-month follow-up and 12-month follow-up. Their results will be analysed using multiple linear regression models and mixed-effects regression models. Further assessment of feasibility and acceptability of the intervention will be conducted through structured interviews with participants, caregivers and therapists. These interviews will be transcribed and thematically analysed.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the Ethics Committee of Taipei Medical University (approval number: N201804055). The findings will be disseminated through presentations at scientific conferences and through publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT03792061; pre-results.

Physiological and pharmacological roles of melatonin in the pathophysiological components of cellular injury after ischemic stroke

Apart from its metabolic or physiological functions, melatonin has a potent cytoprotective activity in the physiological and pathological conditions. It is synthetized by the pineal gland and released into the blood circulation but particularly cerebrospinal fluid in a circadian manner. It can also easily diffuse through cellular membranes due its small size and lipophilic structure. Its cytoprotective activity has been linked to its potent free radical scavenger activity with the desirable characteristics of a clinically- reliable antioxidant. Melatonin detoxifies oxygen and nitrogen-based free radicals and oxidizing agents, including the highly toxic hydroxyl-and peroxynitrite radicals, initiating cellular damage. However, the cytoprotective activity of melatonin is complex and cannot be solely limited to its free radical scavenger activity. It regulates cellular signaling pathways through receptor– dependent and independent mechanisms. Most of these downstream molecules, such as PI3K/AKT pathway components, also contribute to the cytoprotective effects of melatonin. In this term, melatonin is a promising molecule for the treatment of neurodegenerative disorders, such as ischemic stroke, which melatonin reduces ischemic brain injury in animal models of ischemic stroke. It regulates also circadian rhythm proteins after ischemic stroke, playing roles in cellular survival. In this context, present article summarizes the possible role of melatonin in the pathophysiological events after ischemic stroke.

Aescin Protects Neuron from Ischemia-Reperfusion Injury via Regulating the PRAS40/mTOR Signaling Pathway

Ischemic stroke is one of the major causes of disability; widely use of endovascular thrombectomy or intravenous thrombolysis leads to more attention on ischemia-reperfusion injury (I/R injury). Aescin, a natural compound isolated from the seed of the horse chestnut, has been demonstrated anti-inflammatory and antiedematous effects previously. This study was aimed at determining whether aescin could induce protective effects against ischemia-reperfusion injury and exploring the underlying mechanisms in vitro. Primary cultured neurons were subjected to 2 hours of oxygen-glucose deprivation (OGD) followed by 24 hours of simulated reperfusion. Aescin, which worked in a dose-dependent manner, could significantly attenuate neuronal death and reduce lactate dehydrogenase (LDH) release after OGD and simulated reperfusion. Aescin treatment at a concentration of 50 μg/ml provided protection with fewer side effects. Results showed that aescin upregulated the phosphorylation level of PRAS40 and proteins in the mTOR signaling pathway, including S6K and 4E-BP1. However, PRAS40 knockdown or rapamycin treatment was able to undermine and even abolish the protective effects of aescin; meanwhile, the levels of phosphorylation PRAS40 and proteins in the mTOR signaling pathway were obviously decreased. Hence, our study demonstrated that aescin provided neuronal protective effects against I/R injury through the PRAS40/mTOR signaling pathway in vitro. These results might contribute to the potential clinical application of aescin and provide a therapeutic target on subsequent cerebral I/R injury.

Tat-Cannabinoid Receptor Interacting Protein Reduces Ischemia-Induced Neuronal Damage and Its Possible Relationship with 14-3-3η

Cannabinoid receptor-interacting protein 1a (CRIP1a) binds to the C-terminal domain of cannabinoid 1 receptor (CB1R) and regulates CB1R activities. In this study, we made Tat-CRIP1a fusion proteins to enhance CRIP1a penetration into neurons and brain and to evaluate the function of CRIP1a in neuroprotection following oxidative stress in HT22 hippocampal cells and transient forebrain ischemia in gerbils. Purified exogenous Tat-CRIP1a was penetrated into HT22 cells in a time and concentration-dependent manner and prevented H₂O₂-induced reactive oxygen species formation, DNA fragmentation, and cell damage. Tat-CRIP1a fusion protein also ameliorated the reduction of 14-3-3η expression by H₂O₂ treatment in HT22 cells. Ischemia–reperfusion damage caused motor hyperactivity in the open field test of gerbils; however, the treatment of Tat-CRIP1a significantly reduced hyperactivity 1 day after ischemia. Four days after ischemia, the administration of Tat-CRIP1a restored the loss of pyramidal neurons and decreased reactive astrocytosis and microgliosis induced by ischemic damage in the hippocampal cornu Ammonis (CA)1 region. Ischemic damage decreased 14-3-3η expression in all hippocampal sub-regions 4 days after ischemia; however, the treatment of Tat-CRIP1 ameliorated the reduction of 14-3-3η expression. These results suggest that Tat-CRIP1a attenuates neuronal damage and hyperactivity induced by ischemic damage, and it restores normal expression levels of 14-3-3η protein in the hippocampus.

MicroRNA-665-3p attenuates oxygen-glucose deprivation-evoked microglial cell apoptosis and inflammatory response by inhibiting NF-κB signaling via targeting TRIM8

Microglial inflammation induced by ischemic stroke aggravates brain damage. MicroRNAs (miRNAs) have emerged as pivotal regulators in ischemic stroke-induced inflammation in microglial cells. miR-665-3p has been reported as a critical inflammation-associated miRNA. However, whether miR-665-3p participates in regulating microglial inflammation during ischemic stroke is underdetermined. This study investigated the potential role of miR-665-3p in stroke-induced inflammation in microglial cells using a cellular model of oxygen-glucose deprivation (OGD)-stimulated microglial cells in vitro. We found that miR-665-3p expression was decreased in microglial cells exposed to OGD treatment. Functional experiments demonstrated that the overexpression of miR-665-3p attenuated OGD-induced apoptosis and inflammation in microglial cells. Notably, tripartite motif 8 (TRIM8) was identified as a target gene of miR-665-3p. TRIM8 expression was induced by OGD treatment in microglial cells and the knockdown of TRIM8 protected microglial cells from OGD -induced cytotoxicity and inflammation. Moreover, TRIM8 knockdown or miR-665-3p overexpression blocked OGD-induced activation of nuclear factor (NF)-κB signaling in microglial cells. In addition, TRIM8 overexpression partially reversed the miR-665-3p overexpression-mediated inhibitory effect on OGD-induced inflammation in microglial cells. Taken together, these results indicate that miR-665-3p up-regulation protects microglial cells from OGD-induced apoptosis and inflammatory response by targeting TRIM8 to inhibit NF-κB signaling.

Dimeric Diarylheptanoids with Neuroprotective Activities from Rhizomes of Alpinia officinarum

Two novel dimeric diarylheptanoids, alpinidinoids A [(±)-1] and B (2), with two unusual coupling patterns, together with a new naturally occurring diarylheptanoid dimer possessing a rare pyridine ring linkage (alpinidinoid C, 3), were isolated from the rhizomes of Alpinia officinarum. Their structures including absolute configurations were determined by extensive spectroscopic methods and theoretical calculations. All isolates were examined for their neuroprotective activities against oxygen-glucose deprivation and reoxygenation (OGD/R) damage in primary cortical neurons. Remarkably, the dextrorotatory enantiomer of alpinidinoid A [(+)-1] significantly ameliorated OGD/R-induced neuronal apoptosis, which was dependent on the activation of the AKT/mTOR signaling pathway.

Lidocaine mediates the progression of cerebral ischemia/reperfusion injury in rats via inhibiting the activation of NF-κB p65 and p38 MAPK

Background

Lidocaine is a commonly used local anesthetic, and low-dose lidocaine has neuroprotective effects on cerebral ischemia/reperfusion (CI/R) injury; the mechanism for this, however, is still unclear. The aim of this study was to investigate the role and the possible mechanisms of lidocaine on CI/R injury in rats.

Methods

We constructed a rat (male Sprague-Dawley rats, 6–8 weeks old) model of CI/R injury induced by middle cerebral artery occlusion (MCAO). Histopathology, neuronal apoptosis, oxidative stress, and inflammatory response were evaluated using hematoxylin and eosin (HE) staining, Nissl staining, enzyme-linked immunosorbent assay (ELISA) and western blotting, respectively. In addition, brain water content, infarct volume, neurological deficit score each evaluated.

Results

The findings showed that lidocaine improved spatial learning and memory impairment, protected I/R-induced brain injury and attenuated neuronal death and apoptosis. Furthermore, lidocaine also regulated the levels of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), IL-6, IL-10, iNOS, and IL-4.Notably, lidocaine markedly inhibited the expression of p65 and p38.

Conclusions

The results indicate that lidocaine protects against cerebral injury induced by I/R in rats via the nuclear factor kappa-B (NF-κB) p65 and p38 mitogen-activated protein kinase (MAPK) signaling pathway, it provided a candidate for the treatment of CI/R-induced injury.

Improvement in mitochondrial function underlies the effects of ANNAO tablets on attenuating cerebral ischemia-reperfusion injuries

ETHNOPHARMACOLOGICAL RELEVANCE

ANNAO tablets derive from Chinese classical prescriptions of Angong Niuhuang Pills with modified compositions, which have been singly or combined used for stoke associated neurological disorders. However the underlying mechanism is not yet well-defined, the present study investigated its anti-ischemic effects in rat middle cerebral artery occlusion (MCAO) model and focused on mitochondrial quality control.

MATERIALS AND METHODS

Rats were subjected to 2 h of brain ischemia followed by 1 day or up to 7 days of reperfusion. Vehicle, ANNAO tablets or Edaravone were given at 1h after the start of reperfusion for 1 day or successive 7 days in MCAO rats. For the behavior assessment, Longa test and modified Neurological Severity Scores (m NSS) test were performed. Following the behavioral assessment, we assessed the protein expressions related to mitochondrial function. Moreover, we also assessed the neuroprotective effects of ANNAO tablets by immunohistochemical analysis.

RESULTS

Compared with sham rats, ANNAO tablets improved the behavioral performance and decreased the infarction volume in the MCAO rats. Western blotting results showed that ANNAO tablets altered the expression level of multiple proteins related to mitochondrial function, elevated the ratio of Bcl-2/Bax and inhibited the apoptosis. Additionally, ANNAO tablets increased the number of NeuN positive neurons.

CONCLUSIONS

The obtained data demonstrated that ANNAO tablets exhibited an obvious anti-cerebral ischemia-reperfusion effect, which could be attributed to the improvement of mitochondrial quality control.

NLRP6 expressed in astrocytes aggravates neurons injury after OGD/R through activating the inflammasome and inducing pyroptosis

NLRP6, the nucleotide oligomerization domain-like receptor family pyrin domain containing 6, has a substantiable effect on inflammation and host defense against microorganisms. In our previous study, NLRP6 promotes inflammation after cerebral I/R injury in a MCAO model. However, the effect of NLRP6 in different nerve cells subjected to OGD/R needs to be further understood. Here, evidence shows that the expression of NLRP6 is increased in different nerve cells subjected to OGD/R, and mainly expressed in astrocytes. NLRP6 may up-regulate inflammation factors (IL-1β, Il-8) via the form of inflammasomes in astrocytes after OGD/R. Then, primary neuron-astrocyte co-culture model under OGD/R in vitro was performed, and we found that NLRP6 decreased the neurons viability and aggravated apoptosis of neurons. Mechanically, NLRP6 could induce pyroptosis to regulate the survival of neurons through activating caspase-1.

Automated label-free detection of injured neuron with deep learning by two-photon microscopy

Stroke is a significant cause of morbidity and long-term disability globally. Detection of injured neuron is a prerequisite for defining the degree of focal ischemic brain injury, which can be used to guide further therapy. Here, we demonstrate the capability of two-photon microscopy (TPM) to label-freely identify injured neurons on unstained thin section and fresh tissue of rat cerebral ischemia-reperfusion model, revealing definite diagnostic features compared with conventional staining images. Moreover, a deep learning model based on convolutional neural network is developed to automatically detect the location of injured neurons on TPM images. We then apply deep learning-assisted TPM to evaluate the ischemic regions based on tissue edema, two-photon excited fluorescence signal intensity, as well as neuronal injury, presenting a novel manner for identifying the infarct core, peri-infarct area, and remote area. These results propose an automated and label-free method that could provide supplementary information to augment the diagnostic accuracy, as well as hold the potential to be used as an intravital diagnostic tool for evaluating the effectiveness of drug interventions and predicting potential therapeutics.

Sevoflurane attenuates brain damage through inhibiting autophagy and apoptosis in cerebral ischemia‑reperfusion rats

The present study aimed to investigate the effects of sevoflurane post-conditioning in a rat brain cerebral ischemia-reperfusion (I/R) model and examine its possible mechanism. Rats were randomly divided into six groups: Sham control group (Sham), I/R group, sevoflurane group (Se), Toll-like receptor-4 (TLR4) inhibitor group (Tak-242), nuclear factor (NF)-κB inhibitor group (QNZ) and Sevoflurane post-conditioning combined with TLR4-NF-κB signaling pathway inhibitor group (Se + Tak-242). Morris water maze test and tetrazolium chloride staining were used to investigate the I/R injury. The nerve cell apoptosis and autophagy in cortical tissue were detected by TUNEL and transmission electron microscopy, respectively. The expression of TLR4 protein in cortical tissue was observed by immunohistochemical staining. The expression of autophagy and apoptotic associated proteins in cortical tissues and the activity of TLR4-NF-κB signaling pathway were assayed by western blot analysis. Sevoflurane post-conditioning improved the learning and memory dysfunction caused by cerebral I/R injury. The cerebral infarction area, nerve cell apoptosis and formation of autophagic vacuoles were reduced after sevoflurane administration. The expression of light chain 3II/I, Beclin-1, Bad and Cleaved-Caspase-3 proteins were inhibited and the expression of Bcl-2 protein was upregulated after sevoflurane administration. Sevoflurane post-conditioning also inhibited the TLR4 protein and NF-κB phosphorylation, and increased inhibitor of kBα phosphorylation. The treatment effect of Tak-242 and QNZ groups were not significantly different compared with the Se group (P>0.05), and the Se + Tak-242 group had the best results. The present study demonstrated that sevoflurane post-conditioning could protect middle cerebral artery occlusion-induced brain injury rats by inhibiting autophagy and apoptosis, and that its mechanism is related to the TLR4-NF-κB signaling pathway.

Melatonin ameliorates cerebral ischemia/reperfusion injury through SIRT3 activation

AIMS

Previous literature has shown that melatonin plays a critical role in protecting against cerebral ischemia/reperfusion (I/R) injury. Sirtuin3(SIRT3), as one member of the sirtuin family, protects against oxidative stress-related diseases. However, the association between melatonin and SIRT3 in cerebral I/R injury is not well understood. Our experiment was planned to investigate whether melatonin protects against cerebral I/R injury through SIRT3 activation.

MAIN METHODS

We selected transient middle cerebral artery occlusion (tMCAO) mice as the model of cerebral I/R injury. Male C57/BL6 mice were pre-treated with or without a selective SIRT3 inhibitor and then subjected to tMCAO surgery. Melatonin (20 mg/kg) was given to mice by intraperitoneal injection after ischemia and before reperfusion. Then, we observed the changes in the SIRT3 and downstream relative proteins, infarction volume, neurological score, Nissl, H&E and TUNEL staining, and the expression of apoptosis proteins after tMCAO.

KEY FINDINGS

Melatonin upregulated the expression of SIRT3 after tMCAO, and alleviated the neurological dysfunction and cell apoptosis through SIRT3 activation.

SIGNIFICANCE

Our research proved that melatonin promoted SIRT3 expression after tMCAO and alleviated cerebral I/R injury by activating the SIRT3 signaling pathway. This study provides novel therapeutic targets and mechanisms for the treatment of ischemic stroke in the clinic, especially during cerebrovascular reperfusion.

The Neuroprotective Effects of Melatonin: Possible Role in the Pathophysiology of Neuropsychiatric Disease

Melatonin is a hormone that is secreted by the pineal gland. To date, melatonin is known to regulate the sleep cycle by controlling the circadian rhythm. However, recent advances in neuroscience and molecular biology have led to the discovery of new actions and effects of melatonin. In recent studies, melatonin was shown to have antioxidant activity and, possibly, to affect the development of Alzheimer's disease (AD). In addition, melatonin has neuroprotective effects and affects neuroplasticity, thus indicating potential antidepressant properties. In the present review, the new functions of melatonin are summarized and a therapeutic target for the development of new drugs based on the mechanism of action of melatonin is proposed.

Acrolein is involved in ischemic stroke-induced neurotoxicity through spermidine/spermine-N1-acetyltransferase activation

BACKGROUND AND PURPOSE

Ischemic stroke is the most common type of cerebrovascular event and is responsible for approximately 85% of all strokes in Taiwan. Neurons contain high concentrations of polyamines, which are prone to various pathological states in the brain and are perturbed after cerebral ischemia. Acrolein, an α,β-unsaturated aldehyde, has been suggested as the primary culprit of neuronal damage in stroke patients. However, the mechanism by which acrolein induces neuronal damage during ischemic stroke is not clear.

METHODS

Urinary 3-hydroxypropyl mercapturic acid (3-HPMA), an acrolein-glutathione (GSH) metabolite, plasma acrolein-protein conjugates (Acr-PC) and plasma GSH levels were analyzed to correlate disease severity and prognosis of stroke patients compared with control subjects. In vivo middle cerebral artery occlusion (MCAO) animal models and an in vitro oxygen glucose deprivation (OGD) stroke model were used to investigate the mechanisms of acrolein-induced neuronal damage.

RESULTS

A deregulated acrolein metabolism, including significantly increased plasma Acr-PC levels, decreased urinary 3-HPMA levels and decreased plasma GSH levels, was found in stroke patients compared to control subjects. We further observed that acrolein was produced during ischemia resulting in brain damage in in vivo MCAO animal model. The induction of acrolein in neuronal cells during OGD occurred due to the increased expression of spermidine/spermine N1-acetyltransferase (SSAT) by NF-kB pathway activation. In addition, acrolein elicited a vicious cycling of oxidative stress resulting in neurotoxicity. Finally, N-acetylcysteine effectively prevented OGD-induced neurotoxicity by scavenging acrolein.

CONCLUSION

Overall, our current results demonstrate that acrolein is a culprit of neuronal damage through GSH depletion in stroke patients. The mechanism underlying the role of acrolein in stroke-related neuronal damage occurs through SSAT-induced polyamine oxidation by NF-kB pathway activation. These results provide a novel mechanism of neurotoxicity in stroke patients, aid in the development of neutralizing or preventive measures, and further our understanding of neural protection.

Increased interleukin-18 level contributes to the development and severity of ischemic stroke

Although interleukin-18 (IL-18) has been implicated in the pathophysiology of stroke, research findings concerning IL-18 level in stroke have been inconsistent. Thus, we performed a cross-sectional study in patients with first-episode ischemic stroke and then extracted relevant data from databases to validate our results. A total of 252 patients and 259 healthy subjects were recruited, and serum IL-18 level was evaluated in a cross-sectional study. Then, we extracted data and conducted a meta-analysis, including 2,928 patients and 3,739 controls to support our results. A 95% confidence interval for standardized mean difference (SMD) was calculated using a Z test. We found IL-18 was higher in stroke patients than in controls (2.39 ± 0.25 vs. 2.25 ± 0.28, F=8.60, p=0.004) and was negatively associated with the NIHSS scale (r = -0.14, p=0.028). A subsequent meta-analysis confirmed that IL-18 level was higher in stroke patients than in controls (SMD = 2.14, 95% CI = 1.54 ∼ 2.73, P< 0.001). IL-18 level increased with the severity of the stroke (p< 0.01). These findings revealed increased IL-18 level contributed to the development and severity of ischemic stroke, suggesting the potential of this biomarker to become an important reference for the early monitoring of ischemic stroke.

Effects of Cerebrolysin® in Patients With Minimally Conscious State After Stroke: An Observational Retrospective Clinical Study

Introduction: The neurotrophic drug Cerebrolysin is composed of low-molecular-weight peptides and amino acids and has been shown to have neuroprotective and neuroplastic properties. Cerebrolysin has been reported to promote the recovery of motor functions in central nervous system disorders; however, the effects on the consciousness improvements in post-stroke patients have not yet been studied extensively. Therefore, we aimed to examine the effectiveness of Cerebrolysin on improving the consciousness level of stroke patients with minimally conscious state (MCS).

Materials and Methods: In this retrospective study we included ischemic and/or hemorrhagic stroke patients with MCS according to the Coma Recovery Scale-Revised (CRS-R), who were admitted to our hospital between 2014 and 2017. All patients received comprehensive rehabilitation therapy including physical and occupational therapy. We compared patients treated with Cerebrolysin against patients who did not receive Cerebrolysin. Patients were included in the verum group if they received 10 mL of Cerebrolysin IV for at least 20 days. CRS-R scores were assessed at admission and discharge.

Results: Of 1,531 patients screened, 75 were included in the study (Cerebrolysin, n = 43; control, n = 32). Baseline characteristics were similar between groups. At discharge, ~2 months after onset of stroke, Cerebrolysin-treated patients improved significantly in the CRS-R (p = 0.010) after adjustment for confounders using linear mixed model (LMM), especially in the Oromotor (p = 0.003) and Arousal subscales (p = 0.038). No safety issues were observed.

Conclusion: This retrospective study suggests that Cerebrolysin may improve the level of consciousness in stroke patients with MCS, which should be further investigated in a well-designed, double-blind, placebo-controlled, randomized trial.

Neuroprotective Effects of Trolox, Human Chorionic Gonadotropin, and Carnosic Acid on Hippocampal Neurodegeneration After Ischemiareperfusion Injury

INTRODUCTION

One of the serious complications of stroke is memory impairment, which is considered as one of the complications of reperfusion of tissue. The present study was designed to compare the effect of administration of Trolox, carnosic acid and Human Chorionic Gonadotropin (HCG) immediately after reperfusion of the stroke tissue on the memory and hippocampal histology.

METHOD

Ischemia-Reperfusion Model (IRI) was created by bilateral occlusion of the common carotid artery for 15 minutes and the first dose was administered immediately after reperfusion. 10 days after ischemia, passive avoidance memory test and apoptotic protein levels were evaluated.

RESULTS

Cerebral Ischemia perfusion reduced the time of latency in entering the dark box in the ischemic group. Administration of Trolox and HCG increased this latency time, while treatment with carnosic acid had no effect. Also, IRI significantly reduced the number of healthy cells in the hippocampus. Administration of Trolox, carnosic acid and HCG increased the number of healthy cells and decreased the expression of Caspase-3 and Bax, but significantly increased the expression of Bcl-2 compared to the ischemic group.

CONCLUSION

Findings indicate the beneficial effects of HCG and Trolox on the improvement of memory and the number of healthy cells in the hippocampal region. It is worth noting that the amount of apoptosis in the hippocampus was significantly reduced by Trolox, HCG and Carnosic acid.

Post-stroke pain caused by peripheral sensory hypersensitization after transient focal cerebral ischemia in rats

The mechanisms underlying central post-stroke pain are not well understood and there is no satisfactory treatment. Here, in a rat model of stroke, we measured nociceptive threshold using current stimulation of primary afferent neurons in both hind paws. Male Wistar rats underwent middle cerebral artery occlusion (MCAO) for 50 min. Nociceptive thresholds for Aβ, Aδ and C fiber stimulation (at 2000, 250, and 5 Hz, respectively, using a Neurometer), and neurological deficits, were measured for 23 days after MCAO. Sensory thresholds in both hind paws were significantly lower in MCAO model rats than in control rats for 23 days after MCAO, with the greatest difference seen in Aδ fibers and the smallest in C fibers. Brain infarct area was measured histologically, and the correlation between neurological deficit and infarct size was examined. Neurological deficits were worse in animals with larger infarcts. Furthermore, correlations were observed between infarct size, neurological deficit, and sensory threshold of Aδ fibers 1 day after MCAO. These findings indicate that rats develop hyperalgesia after MCAO and that sensory abnormalities in Aδ fibers after cerebral ischemia may play an important role in post-stroke pain.

Necroptosis is one of the modalities of cell death accompanying ischemic brain stroke: from pathogenesis to therapeutic possibilities

Due to very limited therapeutic options, ischemic brain injury is one of the leading causes of death and lifelong disability worldwide, which imposes enormous public health burden. One of the main events occurring with ischemic brain stroke is cell death. Necroptosis is a type of cell death described as a regulated necrosis characterized by cell membrane disruption mediated by phosphorylated mixed lineage kinase like protein (MLKL). It can be triggered by activation of death receptors (eg, FAS, TNFR1), which lead to receptor-interacting serine/threonine-protein kinase 3 (RIPK3) activation by RIPK1 in the absence of active caspase-8. Here, we review articles that have reported that necroptosis significantly contributes to negative events occurring with the ischemic brain stroke, and that its inhibition is protective both in vitro and in vivo. We also review articles describing positive effects obtained by reducing necroptosis, including the reduction of infarct volume and improved functional recovery in animal models. Since necroptosis is characterized by cell content leakage and subsequent inflammation, in addition to reducing cell death, inhibition of necroptosis in ischemic brain stroke also reduces some inflammatory cytokines. By comparing various approaches in inhibition of necroptosis, we analyze the achieved effects from the perspective of controlling necroptosis as a part of future therapeutic interventions in brain ischemia.

Locus coeruleus-CA1 projections are involved in chronic depressive stress-induced hippocampal vulnerability to transient global ischaemia

Depression and transient ischaemic attack represent the common psychological and neurological diseases, respectively, and are tightly associated. However, studies of depression-affected ischaemic attack have been limited to epidemiological evidences, and the neural circuits underlying depression-modulated ischaemic injury remain unknown. Here, we find that chronic social defeat stress (CSDS) and chronic footshock stress (CFS) exacerbate CA1 neuron loss and spatial learning/memory impairment after a short transient global ischaemia (TGI) attack in mice. Whole-brain mapping of direct outputs of locus coeruleus (LC)-tyrosine hydroxylase (TH, Th:) positive neurons reveals that LC-CA1 projections are decreased in CSDS or CFS mice. Furthermore, using designer receptors exclusively activated by designer drugs (DREADDs)-based chemogenetic tools, we determine that Th:LC-CA1 circuit is necessary and sufficient for depression-induced aggravated outcomes of TGI. Collectively, we suggest that Th:LC-CA1 pathway plays a crucial role in depression-induced TGI vulnerability and offers a potential intervention for preventing depression-related transient ischaemic attack.

Obestatin inhibits apoptosis and astrogliosis of hippocampal neurons following global cerebral ischemia reperfusion via antioxidant and anti-inflammatory mechanisms

Objective(s):

Obestatin is a newly discovered peptide with antioxidant activities in different animal models. Recent studies have shown that Obestatin inhibits apoptosis following cardiac ischemia/reperfusion injury. Brain ischemia/reperfusion induces irreversible damage especially in the hippocampus area. This study aimed at examining the protective impact of Obestatin on apoptosis, protein expression and reactive astrogliosis level in hippocampal CA1 region of rat following transient global cerebral ischemia.

Materials and Methods:

Forty-eight male Wistar rats were randomly assigned into 4 groups (sham, ischemia/reperfusion, ischemia/reperfusion+ Obestatin 1, and 5 µg/kg, n=12). Ischemia induced occlusion of both common carotid arteries for 20 min. Obestatin 1 and 5 µg/kg were injected intraperitoneally at the beginning of reperfusion period and 24 and 48 hr after reperfusion. Assessment of the antioxidant enzymes and tumor necrosis factor alpha (TNF-α) was performed by ELISA method. Caspase-3 and glial fibrillary acidic protein (GFAP) proteins expression levels were evaluated by immunohistochemical staining 7 days after ischemia.

Results:

Based on the result of the current study, lower superoxide dismutase (SOD) and glutathione (GSH) (P<0.05) and higher malondialdehyde (MDA) and TNF-α levels were observed in the ischemia group than those of the sham group (P<0.01). Obestatin treatment could increase both SOD and GSH (P<0.05) and reduce MDA and TNF-α (P<0.05) versus the ischemia group. Moreover, obestatin could significantly decrease caspase-3 and GFAP positive cells in the CA1 region of hippocampus (P<0.01).

Conclusion:

Obestatin exerts protective effects against ischemia injury by inhibition of astrocytes activation and decreases neuronal cell apoptosis via its antioxidant properties.

Necroptosis is one of the modalities of cell death accompanying ischemic brain stroke: from pathogenesis to therapeutic possibilities

Due to very limited therapeutic options, ischemic brain injury is one of the leading causes of death and lifelong disability worldwide, which imposes enormous public health burden. One of the main events occurring with ischemic brain stroke is cell death. Necroptosis is a type of cell death described as a regulated necrosis characterized by cell membrane disruption mediated by phosphorylated mixed lineage kinase like protein (MLKL). It can be triggered by activation of death receptors (eg, FAS, TNFR1), which lead to receptor-interacting serine/threonine-protein kinase 3 (RIPK3) activation by RIPK1 in the absence of active caspase-8. Here, we review articles that have reported that necroptosis significantly contributes to negative events occurring with the ischemic brain stroke, and that its inhibition is protective both in vitro and in vivo. We also review articles describing positive effects obtained by reducing necroptosis, including the reduction of infarct volume and improved functional recovery in animal models. Since necroptosis is characterized by cell content leakage and subsequent inflammation, in addition to reducing cell death, inhibition of necroptosis in ischemic brain stroke also reduces some inflammatory cytokines. By comparing various approaches in inhibition of necroptosis, we analyze the achieved effects from the perspective of controlling necroptosis as a part of future therapeutic interventions in brain ischemia.

Inhibition of microRNA-429 attenuates oxygen-glucose deprivation/reoxygenation-induced neuronal injury by promoting expression of GATA-binding protein 4

MicroRNAs (miRNAs) have been documented as critical regulators in ischemia/reperfusion-induced neuronal death. A better understanding of miRNA-mediated molecular mechanisms in ischemia/reperfusion-induced neuronal death may provide therapeutic targets for cerebral ischemia/reperfusion injury. A growing body of evidence suggests that miR-429 is a apoptosis-related miRNA that is also induced by hypoxia. However, whether miR-429 is involved in regulating neuronal apoptosis during cerebral ischemia/reperfusion injury remains unclear. In this study, the effect of miR-429 on oxygen-glucose deprivation and reoxygenation (OGD/R)-induced neuronal injury was investigated in vitro. The results showed that miR-429 expression levels were upregulated in cultured neurons with OGD/R treatment. The downregulation of miR-429 significantly alleviated OGD/R-induced neuronal injury, whereas upregulation of miR-429 aggravated it. Bioinformatic analysis showed that miR-429 could directly target the 3'-untranslated region of GATA-binding protein 4 (GATA4), which was verified by dual-luciferase reporter assay. Moreover, we found that miR-429 negatively regulated GATA4 expression. Overexpression of GATA4 also significantly alleviated OGD/R-induced neuronal injury. However, knockdown of GATA4 partially reversed the protective effect induced by miR-429 downregulation. Overall, our data showed that downregulation of miR-429 protected neurons against OGD/R-induced injury by promoting GATA4 and suggested a potential therapeutic target for the treatment of cerebral ischemia/reperfusion injury.

Design, synthesis and biological evaluation of chalcone analogues with novel dual antioxidant mechanisms as potential anti-ischemic stroke agents

Scavenging reactive oxygen species (ROS) by antioxidants is the important therapy to cerebral ischemia-reperfusion injury (CIRI) in stroke. The antioxidant with novel dual-antioxidant mechanism of directly scavenging ROS and indirectly through antioxidant pathway activation may be a promising CIRI therapeutic strategy. In our study, a series of chalcone analogues were designed and synthesized, and multiple potential chalcone analogues with dual antioxidant mechanisms were screened. Among these compounds, the most active 33 not only conferred cytoprotection of H2O2-induced oxidative damage in PC12 cells through scavenging free radicals directly and activating NRF2/ARE antioxidant pathway at the same time, but also played an important role against ischemia/reperfusion-related brain injury in animals. More importantly, in comparison with mono-antioxidant mechanism compounds, 33 exhibited higher cytoprotective and neuroprotective potential in vitro and in vivo. Overall, our findings showed compound 33 could emerge as a promising anti-ischemic stroke drug candidate and provided novel dual-antioxidant mechanism strategies and concepts for oxidative stress-related diseases treatment.

MicroRNA-124 expression in the brains of rats during early cerebral ischemia and reperfusion injury is associated with cell apoptosis involving STAT3

Cerebral ischemia and reperfusion injury is a cause of death and disability in adults. MicroRNA-124 possesses protective effects against apoptosis in cerebral ischemia and reperfusion. To provide insights into the diagnosis and treatment of cerebral ischemia and reperfusion injury, the dynamic changes of microRNA-124 expression during the early stage of cerebral ischemia and reperfusion injury in rats was investigated by quantitative polymerase chain reaction. To elucidate the association between the dynamic expression of microRNA-124 and apoptosis, the expression of proteins associated with apoptosis, including caspase-3, apoptosis regulator Bcl-2 (Bcl-2) and apoptosis regulator Bax (Bax) was analyzed by immunohistochemistry and western blot analyses. As signal transducer and activator of transcription 3 (STAT3) is involved in cell apoptosis and associated with Bcl-2, the protein expression of STAT3 and its active form, phosphorylated (p-)STAT3, were analyzed by western blot analysis. The expression of microRNA-124 increased and the maximum value appeared 12 h after reperfusion. Similarly, the expression of Bcl-2 also peaked 12 h after reperfusion, however the expression of caspase-3 and Bax continued to increase after the 12 h time point. These results indicate that the expression of microRNA-124 is closely associated with Bcl-2 and serves a protective role, inhibiting apoptosis. As the upstream regulator of Bcl-2, the expression of p-STAT3 was in accordance with Bcl-2 expression and peaked 12 h after reperfusion. By contrast, STAT3 was downregulated and the minimum level of STAT3 protein was reached 12 h after reperfusion. In summary, during the early stage of cerebral ischemia and reperfusion, the dynamic expression of microRNA-124 exhibited protective effects through the inhibition of apoptosis via anti-apoptotic proteins Bcl-2 and STAT3. Conversely, caspase-3 and Bax maintain apoptosis. The present study provides evidence to aid in the understanding of cerebral ischemia and reperfusion injury and develops methods of diagnosis and therapy of this condition.

The neuroprotective role of melatonin in neurological disorders

Melatonin is a neurohormone secreted from the pineal gland and has a wide-ranging regulatory and neuroprotective role. It has been reported that melatonin level is disturbed in some neurological conditions such as stroke, Alzheimer's disease, and Parkinson's disease, which indicates its involvement in the pathophysiology of these diseases. Its properties qualify it to be a promising potential therapeutic neuroprotective agent, with no side effects, for some neurological disorders. This review discusses and localizes the effect of melatonin in the pathophysiology of some diseases.

Octadecylpropyl Sulfamide Reduces Neurodegeneration and Restores the Memory Deficits Induced by Hypoxia-Ischemia in Mice

The PPAR-α agonist, oleoylethanolamide (OEA) has neuroprotective properties in stroke models. However, its rapid degradation represents a limitation for an effective therapeutic approach. In this study, we evaluated the effects of a stable OEA-modeled compound, octadecylpropyl sulfamide (SUL) on the cognitive, behavioral, cellular and molecular alterations associated with hypoxia-ischemia (HI) in mice. Mice subjected to HI were treated with the PPAR-α antagonist GW6471 (GW) (1 mg/kg) followed 15 min later by SUL (3 and 10 mg/kg). Behavioral, motor, and cognitive tests were carried out 24 h and 7 days after the HI. The levels of microglia, reactive astrocytes and neuronal nuclei were studied using immunofluorescence, and the expression of genes related to the N-acyl-ethanolamides/endocannabinoid signaling systems was determined by qRT-PCR at the end of the experimental sequence. HI induced brain damage in the ipsilateral hippocampus and cortex, which lead to severe memory impairments, and motor coordination deficits. Significant neuronal loss, increased microglia and reactive astrocytes, and compensatory changes in genes associated with the inflammation/immune and endocannabinoid systems were observed in these brain structures of lesioned mice. SUL reversed the memory and motor deficits, decreased the overexpression of microglia and astrocytes, and reduced neurodegeneration induced by HI. Cnr1 and Cnr2 gene expression was modulated by SUL in both sham and HI mice, while Pparα and Faah expression was regulated in HI mice. GW completely blocked the beneficial actions of SUL. These findings suggest that treatment with SUL reduces brain damage and the associated motor and memory deficits induced by HI probably by normalizing the changes in neuroinflammation/immune system mediators.

Tau pathology and neurochemical changes associated with memory dysfunction in an optimised murine model of global cerebral ischaemia - A potential model for vascular dementia?

Cerebral ischemia is known to be a major cause of death and the later development of Alzheimer's disease and vascular dementia. However, ischemia induced cellular damage that initiates these diseases remain poorly understood. This is primarily due to lack of clinically relevant models that are highly reproducible. Here, we have optimised a murine model of global cerebral ischaemia with multiple markers to determine brain pathology, neurochemistry and correlated memory deficits in these animals. Cerebral ischaemia in mice was induced by bilateral common carotid artery occlusion. Following reperfusion, the mice were either fixed with 4% paraformaldehyde or decapitated under anaesthesia. Brains were processed for Western blotting or immunohistochemistry for glial (GLT1) and vesicular (VGLUT1, VGLUT2) glutamate transporters and paired helical filament (PHF1) tau. The PHF1 tau is the main component of neurofibrillary tangle, which is the pathological hallmark of Alzheimer's disease and vascular dementia. The novel object recognition behavioural assay was used to investigate the functional cognitive consequences in these mice. The results show consistent and selective neuronal and glial cell changes in the hippocampus and the cortex together with significant reductions in GLT1 (***P < 0.001), VGLUT1 (**P < 0.01) and VGLUT2 (***P < 0.001) expressions in the hippocampus in occluded mice as compared to sham-operated animals. These changes are associated with increased PHF1 (***P < 0.0001) protein and a significant impairment of performance (*p < 0.0006, N = 6/group) in the novel object recognition test. This model represents a useful tool for investigating cellular, biochemical and molecular mechanisms of global cerebral ischaemia and may be an ideal preclinical model for vascular dementia.