Neurovascular Unit: A critical role in ischemic stroke

NADPH Oxidases in Neurodegenerative Disorders: Mechanisms and Therapeutic Opportunities

Significance: The nicotinamide adenine dinucleotide phosphate oxidase (NOX) enzyme family, located in the central nervous system, is recognized as a source of reactive oxygen species (ROS) in the brain. Despite its importance in cellular processes, excessive ROS generation leads to cell death and is involved in the pathogenesis of neurodegenerative disorders. Recent advances: NOX enzymes contribute to the development of neurodegenerative diseases, such as Parkinson's disease (PD), Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), and stroke, highlighting their potential as targets for future therapeutic development. This review will discuss NOX's contribution and therapeutic targeting potential in neurodegenerative diseases, focusing on PD, AD, ALS, and stroke. Critical issues: Homeostatic and physiological levels of ROS are crucial for regulating several processes, such as development, memory, neuronal signaling, and vascular homeostasis. However, NOX-mediated excessive ROS generation is deeply involved in the damage of DNA, proteins, and lipids, leading to cell death in the pathogenesis of a wide range of diseases, namely neurodegenerative diseases. Future directions: It is essential to understand the role of NOX homologs in neurodegenerative disorders and the pathological mechanisms undergoing neurodegeneration mediated by increased levels of ROS. This further knowledge will allow the development of new specific NOX inhibitors and their application for neurodegenerative disease therapeutics.

The protective effects of Axitinib on blood-brain barrier dysfunction and ischemia-reperfusion injury in acute ischemic stroke

BACKGROUND AND PURPOSE

The pathophysiological features of acute ischemic stroke (AIS) often involve dysfunction of the blood-brain barrier (BBB), characterized by the degradation of tight junction proteins (Tjs) leading to increased permeability. This dysfunction can exacerbate cerebral injury and contribute to severe complications. The permeability of the BBB fluctuates during different stages of AIS and is influenced by various factors. Developing effective therapies to restore BBB function remains a significant challenge in AIS treatment. High levels of vascular endothelial growth factor (VEGF) in the early stages of AIS have been shown to worsen BBB breakdown and stroke progression. Our study aimed to investigate the protective effects of the VEGF receptor inhibitor Axitinib on BBB dysfunction and cerebral ischemia/reperfusion-induced injury.

METHODS

BEnd3 cell exposed to oxygen-glucose deprivation (OGD) model was constructed to estimate pharmacological activity of Axitinib (400 ng/ml) on anti-apoptosis and pathological barrier function recovery. In vivo, rats were subjected to a 1 h transient middle cerebral artery occlusion and 23 h reperfusion (tMCAO/R) to investigate the permeability of BBB and cerebral tissue damage. Axitinib was administered through the tail vein at the beginning of reperfusion. BBB integrity was assessed by Evans blue leakage and the expression levels of Tjs claudin-5 and occludin.

RESULTS

Our research revealed that co-incubation with Axitinib enhanced the cell viability of OGD-insulted bEnd3 cells, decreased LDH leakage rate, and suppressed the expression of apoptosis-related proteins cytochrome C and Bax. Axitinib also mitigated the damage to Tjs and facilitated the restoration of transepithelial electrical resistance in OGD-insulted bEnd.3 cells. In vivo, Axitinib administration reduced intracerebral Evans blue leakage and up-regulated the expression of Tjs in the penumbra brain tissue in tMCAO/R rats. Notably, 10 mg/kg Axitinib exerted a significant anti-ischemic effect by decreasing cerebral infarct volume and brain edema volume, improving neurological function, and reducing pro-inflammatory cytokines IL-6 and TNF-α in the brain.

CONCLUSIONS

Our study highlights Axitinib as a potent protectant of blood-brain barrier function, capable of promoting pathological blood-brain barrier recovery through VEGF inhibition and increased expression of tight junction proteins in AIS. This suggests that VEGF antagonism within the first 24 h post-stroke could be a novel therapeutic approach to enhance blood-brain barrier function and mitigate ischemia-reperfusion injury.

Catalpol attenuates ischemic stroke by promoting neurogenesis and angiogenesis via the SDF-1α/CXCR4 pathway

BACKGROUND

Stroke is a leading cause of disability and death worldwide. Currently, there is a lack of clinically effective treatments for the brain damage following ischemic stroke. Catalpol is a bioactive compound derived from the traditional Chinese medicine Rehmannia glutinosa and shown to be protective in various neurological diseases. However, the potential roles of catalpol against ischemic stroke are still not completely clear.

PURPOSE

This study aimed to further elucidate the protective effects of catalpol against ischemic stroke.

METHODS

A rat permanent middle cerebral artery occlusion (pMCAO) and oxygen-glucose deprivation (OGD) model was established to assess the effect of catalpol in vivo and in vitro, respectively. Behavioral tests were used to examine the effects of catalpol on neurological function of ischemic rats. Immunostaining was performed to evaluate the proliferation, migration and differentiation of neural stem cells (NSCs) as well as the angiogenesis in each group. The protein level of related molecules was detected by western-blot. The effects of catalpol on cultured NSCs as well as brain microvascular endothelial cells (BMECs) subjected to OGD in vitro were also examined by similar methods.

RESULTS

Catalpol attenuated the neurological deficits and improved neurological function of ischemic rats. It stimulated the proliferation of NSCs in the subventricular zone (SVZ), promoted their migration to the ischemic cortex and differentiation into neurons or glial cells. At the same time, catalpol increased the cerebral vessels density and the number of proliferating cerebrovascular endothelial cells in the infracted cortex of ischemic rats. The level of SDF-1α and CXCR4 in the ischemic cortex was found to be enhanced by catalpol treatment. Catalpol was also shown to promote the proliferation and migration of cultured NSCs as well as the proliferation of BMECs subjected to OGD insult in vitro. Interestingly, the impact of catalpol on cultured cells was inhibited by CXCR4 inhibitor AMD3100. Moreover, the culture medium of BMECs containing catalpol promoted the proliferation of NSCs, which was also suppressed by AMD3100.

CONCLUSION

Our data demonstrate that catalpol exerts neuroprotective effects by promoting neurogenesis and angiogenesis via the SDF-1α/CXCR4 pathway, suggesting the therapeutic potential of catalpol in treating cerebral ischemia.

Sevoflurane postconditioning ameliorates cerebral hypoxia/reoxygenation injury in zebrafish involving the Akt/GSK-3β pathway activation and the microtubule-associated protein 2 promotion

Sevoflurane postconditioning has been shown to provide neuroprotection against cerebral hypoxia-ischemia injury, but the mechanisms remain elusive. Microtubule-associated protein 2 (MAP2) is implicated in early neuronal hypoxia-ischemia injury. This study aimed to investigate whether the neuroprotective effects of sevoflurane postconditioning are related to the Akt/GSK-3β pathway and its downstream target MAP2 in zebrafish hypoxia/reoxygenation (H/R) model. Sevoflurane postconditioning or GSK-3β inhibitor TDZD-8 were used to treat H/R zebrafish. The cerebral infarction, neuronal apoptosis, and mitochondrial changes were evaluated using TTC staining, TUNEL staining, and transmission electron microscopy, respectively. The distribution of MAP2 in the brain was determined by immunofluorescence imaging. The levels of Akt, p-Akt, GSK-3β, p-GSK-3β, and MAP2 proteins were evaluated by Western blotting. The neurobehavioral recovery of zebrafish was assessed based on optokinetic response behavior. Our results indicated that sevoflurane postconditioning and TDZD-8 significantly reduced the cerebral infarction area, suppressed cell apoptosis, and improved mitochondrial integrity in zebrafish subjected to H/R. Furthermore, sevoflurane postconditioning and TDZD-8 elevated the ratios of p-Akt/Akt and p-GSK-3β/GSK-3β. However, the neuroprotective effect of sevoflurane postconditioning was effectively abolished upon suppression of MAP2 expression. In conclusion, sevoflurane postconditioning ameliorated cerebral H/R injury and facilitated the restoration of neurobehavioral function through the activation of Akt/GSK-3β pathway and promotion of MAP2 expression.

Cerebral hemodynamics and cognitive functions in the acute and subacute stage of mild ischemic stroke: a longitudinal pilot study

The association between cerebral hemodynamics and cognitive impairment has been reported in neurodegenerative and cerebrovascular disorders (CVD). However, it is still unclear whether changes occur in the acute phase of CVD. Here we investigated cognitive and hemodynamic parameters and their association in patients with CVD during the acute and subacute phases. Seventy-three patients with mild stroke, not undergoing endovascular treatment, were recruited. All subjects were devoid of intracranial or external carotid stenosis, significant chronic cerebrovascular pathology, dementia or non-compensated cardiovascular diseases. Patients were evaluated within 7 days from symptoms onset (T1) and after 3 months (T2). Clinical and demographic data were collected. NIHSS, MoCA, FAB, and Word-Color Stroop test (WCST) were used to evaluate disease severity and cognitive functions. Basal hemodynamic parameters in the middle cerebral artery were measured with transcranial Doppler. Differences between T2 and T1, correlations between cognitive and hemodynamic variables at T1 and T2, as well as correlations between the T2-T1 variation in cognitive and hemodynamic parameters were assessed. At T1, cognitive performance of MoCA, FAB, and WCST was lower compared with T2; and pulsatility index, a parameter reflecting distal vascular resistance, was higher. However, no correlations between the changes in cognitive and hemodynamic variables were found; therefore, the two seems to be independent phenomena. In the acute phase, the linear association between cerebral blood flow and cognitive performances was lost, probably due to a differential effect of microenvironment changes and vascular-specific phenomena on cognition and cerebral hemodynamics. This relationship was partially restored in the subacute phase.

Assessment of Neurovascular Coupling by Spectral Analysis of Cerebral Blood Flow Velocity With Transcranial Doppler

OBJECTIVE

Neurovascular coupling (NVC) represents the increase in regional blood flow associated with neural activity. The aim here was to describe a new approach to non-invasive measurement of NVC by spectral analysis of the cerebral blood flow velocity (CBFV) with transcranial Doppler.

METHODS

In a sample of 20 healthy participants, we monitored systolic CBFV in the left posterior cerebral artery (PCA) during off (eyes closed) and on (flickering checkerboard) periods. The contralateral middle cerebral artery was simultaneously monitored as a control. Each participant was submitted to three experiments, each having five cycles, with increasing duration of the cycles, from 10 s (0.1 Hz) to 20 s (0.05 Hz) and lastly 40 s (0.025 Hz), half the time for on and for off periods, constituting a total of 6 min. The successive cycles were expected to cause oscillation in CBFV in a sinusoidal pattern that could be characterized by spectral analysis. We also measured the classic CBFV overshoot as the relative increase in percentage of systolic CBFV from baseline. The relationship and agreement between the two methods were analyzed by linear regression and Bland-Altman plots. In every participant, a clear peak of amplitude in the PCA CBFV spectrum was discernible at 0.1, 0.05 and 0.025 Hz of visual stimulation.

RESULTS

On average, this amplitude was 7.1 ± 2.3%, 10.9 ± 3.5% and 17.3 ± 6.5%, respectively. This response contrasted significantly with an absent peak in middle cerebral artery monitoring (p < 0.0001). The spectral amplitude and classic overshoot were highly correlated and linearly related (p < 0.0001).

CONCLUSION

NVC can be quantified by the spectral amplitude of PCA CBFV at slower and higher frequencies of visual stimulation. This method represents an alternative to classic overshoot without the need for stimulus marking or synchronization.

Drugs/agents for the treatment of ischemic stroke: Advances and perspectives

Ischemic stroke (IS) poses a significant threat to global human health and life. In recent decades, we have witnessed unprecedented progresses against IS, including thrombolysis, thrombectomy, and a few medicines that can assist in reopening the blocked brain vessels or serve as standalone treatments for patients who are not eligible for thrombolysis/thrombectomy therapies. However, the narrow time windows of thrombolysis/thrombectomy, coupled with the risk of hemorrhagic transformation, as well as the lack of highly effective and safe medications, continue to present big challenges in the acute treatment and long-term recovery of IS. In the past 3 years, several excellent articles have reviewed pathophysiology of IS and therapeutic medicines for the treatment of IS based on the pathophysiology. Regretfully, there is no comprehensive overview to summarize all categories of anti-IS drugs/agents designed and synthesized based on molecular mechanisms of IS pathophysiology. From medicinal chemistry view of point, this article reviews a multitude of anti-IS drugs/agents, including small molecule compounds, natural products, peptides, and others, which have been developed based on the molecular mechanism of IS pathophysiology, such as excitotoxicity, oxidative/nitrosative stresses, cell death pathways, and neuroinflammation, and so forth. In addition, several emerging medicines and strategies, including nanomedicines, stem cell therapy and noncoding RNAs, which recently appeared for the treatment of IS, are shortly introduced. Finally, the perspectives on the associated challenges and future directions of anti-IS drugs/agents are briefly provided to move the field forward.

The Role of Neutrophils in Multiple Sclerosis and Ischemic Stroke

Inflammation plays an important role in numerous central nervous system (CNS) disorders. Its role is ambiguous-it can induce detrimental effects, as well as repair and recovery. In response to injury or infection, resident CNS cells secrete numerous factors that alter blood-brain barrier (BBB) function and recruit immune cells into the brain, like neutrophils. Their role in the pathophysiology of CNS diseases, like multiple sclerosis (MS) and stroke, is highly recognized. Neutrophils alter BBB permeability and attract other immune cells into the CNS. Previously, neutrophils were considered a homogenous population. Nowadays, it is known that various subtypes of these cells exist, which reveal proinflammatory or immunosuppressive functions. The primary goal of this review was to discuss the current knowledge regarding the important role of neutrophils in MS and stroke development and progression. As the pathogenesis of these two disorders is completely different, it gives the opportunity to get insight into diverse mechanisms of neutrophil involvement in brain pathology. Our understanding of the role of neutrophils in CNS diseases is still evolving as new aspects of their activity are being unraveled. Neutrophil plasticity adds another level to their functional complexity and their importance for CNS pathophysiology.

Rhoa/ROCK, mTOR and Secretome-Based Treatments for Ischemic Stroke: New Perspectives

Ischemic stroke triggers a complex cascade of cellular and molecular events leading to neuronal damage and tissue injury. This review explores the potential therapeutic avenues targeting cellular signaling pathways implicated in stroke pathophysiology. Specifically, it focuses on the articles that highlight the roles of RhoA/ROCK and mTOR signaling pathways in ischemic brain injury and their therapeutic implications. The RhoA/ROCK pathway modulates various cellular processes, including cytoskeletal dynamics and inflammation, while mTOR signaling regulates cell growth, proliferation, and autophagy. Preclinical studies have demonstrated the neuroprotective effects of targeting these pathways in stroke models, offering insights into potential treatment strategies. However, challenges such as off-target effects and the need for tissue-specific targeting remain. Furthermore, emerging evidence suggests the therapeutic potential of MSC secretome in stroke treatment, highlighting the importance of exploring alternative approaches. Future research directions include elucidating the precise mechanisms of action, optimizing treatment protocols, and translating preclinical findings into clinical practice for improved stroke outcomes.

The Temporal Relationship between Blood-Brain Barrier Integrity and Microglial Response following Neonatal Hypoxia Ischemia

Blood-brain barrier (BBB) dysfunction and neuroinflammation are key mechanisms of brain injury. We performed a time-course study following neonatal hypoxia-ischemia (HI) to characterize these events. HI brain injury was induced in postnatal day 10 rats by single carotid artery ligation followed by hypoxia (8% oxygen, 90 min). At 6, 12, 24, and 72 h (h) post-HI, brains were collected to assess neuropathology and BBB dysfunction. A significant breakdown of the BBB was observed in the HI injury group compared to the sham group from 6 h in the cortex and hippocampus (p < 0.001), including a significant increase in albumin extravasation (p < 0.0033) and decrease in basal lamina integrity and tight-junction proteins. There was a decrease in resting microglia (p < 0.0001) transitioning to an intermediate state from as early as 6 h post-HI, with the intermediate microglia peaking at 12 h (p < 0.0001), which significantly correlated to the peak of microbleeds. Neonatal HI insult leads to significant brain injury over the first 72 h that is mediated by BBB disruption within 6 h and a transitioning state of the resident microglia. Key BBB events coincide with the appearance of the intermediate microglial state and this relationship warrants further research and may be a key target for therapeutic intervention.

Combination therapy of Epidermal Growth Factor and Growth Hormone-Releasing Hexapeptide in acute ischemic stroke: a phase I/II non-blinded, randomized clinical trial

Objective

This study tested the hypothesis that a neuroprotective combined therapy based on epidermal growth factor (EGF) and growth hormone-releasing hexapeptide (GHRP6) could be safe for acute ischemic stroke patients, admitting up to 30% of serious adverse events (SAE) with proven causality.

Methods

A multi-centric, randomized, open-label, controlled, phase I-II clinical trial with parallel groups was conducted (July 2017 to January 2018). Patients aged 18-80 years with a computed tomography-confirmed ischemic stroke and less than 12 h from the onset of symptoms were randomly assigned to the study groups I (75 μg rEGF + 3.5 mg GHRP6 i.v., n=10), II (75 μg rEGF + 5 mg GHRP6 i.v., n=10), or III (standard care control, n=16). Combined therapy was given BID for 7 days. The primary endpoint was safety over 6 months. Secondary endpoints included neurological (NIHSS) and functional [Barthel index and modified Rankin scale (mRS)] outcomes.

Results

The study population had a mean age of 66 ± 11 years, with 21 men (58.3%), a baseline median NIHSS score of 9 (95% CI: 8-11), and a mean time to treatment of 7.3 ± 2.8 h. Analyses were conducted on an intention-to-treat basis. SAEs were reported in 9 of 16 (56.2%) patients in the control group, 3 of 10 (30%) patients in Group I (odds ratio (OR): 0.33; 95% CI: 0.06-1.78), and 2 of 10 (20%) patients in Group II (OR: 0.19; 95% CI: 0.03-1.22); only two events in one patient in Group I were attributed to the intervention treatment. Compliance with the study hypothesis was greater than 0.90 in each group. Patients treated with EGF + GHRP6 had a favorable neurological and functional evolution at both 90 and 180 days, as evidenced by the inferential analysis of NIHSS, Barthel, and mRS and by their moderate to strong effect size. At 6 months, proportion analysis evidenced a higher survival rate for patients treated with the combined therapy. Ancillary analysis including merged treated groups and utility-weighted mRS also showed a benefit of this combined therapy.

Conclusion

EGF + GHRP6 therapy was safe. The functional benefits of treatment in this study supported a Phase III study.

Clinical Trial Registration

RPCEC00000214 of the Cuban Public Registry of Clinical Trials, Unique identifier: IG/CIGB-845I/IC/1601.

Stem cell factor protects against chronic ischemic retinal injury by modulating on neurovascular unit

Retinal ischemia is a significant factor in various vision-threatening diseases, but effective treatments are currently lacking. This study explores the potential of stem cell factor (SCF) in regulating the neurovascular unit as a therapeutic intervention for retinal ischemic diseases. A chronic retinal ischemia model was established in Brown Norway rats using bilateral common carotid artery occlusion (BCCAO). Subsequent SCF treatment resulted in a remarkable recovery of retinal function, as indicated by electroretinogram, light/dark transition test, and optokinetic head tracking test results. Histological examination demonstrated a significant increase in the number of retinal neurons and an overall thickening of the retina. Immunofluorescence confirmed these findings and further demonstrated that SCF treatment regulated retinal remodeling. Notably, SCF treatment ameliorated the disrupted expression of synaptic markers in the control group's BCCAO rats and suppressed the activation of Müller cells and microglia. Retinal whole-mount analysis revealed a significant improvement in the abnormalities in retinal vasculature following SCF treatment. Transcriptome sequencing analysis revealed that SCF-induced transcriptome changes were closely linked to the Wnt7 pathway. Key members of the Wnt7 pathway, exhibited significant upregulation following SCF treatment. These results underscore the protective role of SCF in the neurovascular unit of retinal ischemia rats by modulating the Wnt7 pathway. SCF administration emerges as a promising therapeutic strategy for retinal ischemia-related diseases, offering potential avenues for future clinical interventions.

Deciphering Post-Stroke Sleep Disorders: Unveiling Neurological Mechanisms in the Realm of Brain Science

Sleep disorders are the most widespread mental disorders after stroke and hurt survivors' functional prognosis, response to restoration, and quality of life. This review will address an overview of the progress of research on the biological mechanisms associated with stroke-complicating sleep disorders. Extensive research has investigated the negative impact of stroke on sleep. However, a bidirectional association between sleep disorders and stroke exists; while stroke elevates the risk of sleep disorders, these disorders also independently contribute as a risk factor for stroke. This review aims to elucidate the mechanisms of stroke-induced sleep disorders. Possible influences were examined, including functional changes in brain regions, cerebrovascular hemodynamics, neurological deficits, sleep ion regulation, neurotransmitters, and inflammation. The results provide valuable insights into the mechanisms of stroke complicating sleep disorders.

A review of concepts and methods for FTIR imaging of biomarker changes in the post-stroke brain

Stroke represents a core area of study in neurosciences and public health due to its global contribution toward mortality and disability. The intricate pathophysiology of stroke, including ischemic and hemorrhagic events, involves the interruption in oxygen and nutrient delivery to the brain. Disruption of these crucial processes in the central nervous system leads to metabolic dysregulation and cell death. Fourier transform infrared (FTIR) spectroscopy can simultaneously measure total protein and lipid content along with a number of key biomarkers within brain tissue that cannot be observed using conventional techniques. FTIR imaging provides the opportunity to visualize this information in tissue which has not been chemically treated prior to analysis, thus retaining the spatial distribution and in situ chemical information. Here we present a review of FTIR imaging methods for investigating the biomarker responses in the post-stroke brain.

Malignancy-associated ischemic stroke: Implications for diagnostic and therapeutic workup

BACKGROUND

Patients with malignancies have an increased risk of suffering ischemic stroke via several mechanisms such as coagulation dysfunction and other malignancy-related effects as well as iatrogenic causes. Moreover, stroke can be the first sign of an occult malignancy, termed as malignancy-associated ischemic stroke (MAS). Therefore, timely diagnostic assessment and targeted management of this complex clinical situation are critical.

FINDINGS

Patients with both stroke and malignancy have atypical ages, risk factors, and often exhibit malignancy-related symptoms and multiple lesions on neuroimaging. New biomarkers such as eicosapentaenoic acid and blood mRNA profiles may help in distinguishing MAS from other strokes. In terms of treatment, malignancy should not be considered a contraindication, given comparable rates of recanalization and complications between stroke patients with or without malignancies.

CONCLUSION

In this review, we summarize the latest developments in diagnosing and managing MAS, especially stroke with occult malignancies, and provide new recommendations from recently emerged clinical evidence for diagnostic and therapeutic workup strategies.

Challenges and prospects in geriatric epilepsy treatment: the role of the blood-brain barrier in pharmacotherapy and drug delivery

The blood-brain barrier (BBB) is pivotal in maintaining neuronal physiology within the brain. This review delves into the alterations of the BBB specifically in the context of geriatric epilepsy. We examine how age-related changes in the BBB contribute to the pathogenesis of epilepsy in the elderly and present significant challenges in pharmacotherapy. Subsequently, we evaluate recent advancements in drug delivery methods targeting the BBB, as well as alternative approaches that could bypass the BBB's restrictive nature. We particularly highlight the use of neurotropic viruses and various synthetic nanoparticles that have been investigated for delivering a range of antiepileptic drugs. Additionally, the advantage and limitation of these diverse delivery methods are discussed. Finally, we analyze the potential efficacy of different drug delivery approaches in the treatment of geriatric epilepsy, aiming to provide insights into more effective management of this condition in the elderly population.

Therapeutic Potential of Natural Compounds from Herbs and Nutraceuticals in Alleviating Neurological Disorders: Targeting the Wnt Signaling Pathway

As an important signaling pathway in multicellular eukaryotes, the Wnt signaling pathway participates in a variety of physiological processes. Recent studies have confirmed that the Wnt signaling pathway plays an important role in neurological disorders such as stroke, Alzheimer's disease, and Parkinson's disease. The regulation of Wnt signaling by natural compounds in herbal medicines and nutraceuticals has emerged as a potential strategy for the development of new drugs for neurological disorders. Purpose: The aim of this review is to evaluate the latest research results on the efficacy of natural compounds derived from herbs and nutraceuticals in the prevention and treatment of neurological disorders by regulating the Wnt pathway in vivo and in vitro. A manual and electronic search was performed for English articles available from PubMed, Web of Science, and ScienceDirect from the January 2010 to February 2023. Keywords used for the search engines were "natural products,″ "plant derived products,″ "Wnt+ clinical trials,″ and "Wnt+,″ and/or paired with "natural products″/″plant derived products", and "neurological disorders." A total of 22 articles were enrolled in this review, and a variety of natural compounds from herbal medicine and nutritional foods have been shown to exert therapeutic effects on neurological disorders through the Wnt pathway, including curcumin, resveratrol, and querctrin, etc. These natural products possess antioxidant, anti-inflammatory, and angiogenic properties, confer neurovascular unit and blood-brain barrier integrity protection, and affect neural stem cell differentiation, synaptic formation, and neurogenesis, to play a therapeutic role in neurological disorders. In various in vivo and in vitro studies and clinical trials, these natural compounds have been shown to be safe and tolerable with few adverse effects. Natural compounds may serve a therapeutic role in neurological disorders by regulating the Wnt pathway. This summary of the research progress of natural compounds targeting the Wnt pathway may provide new insights for the treatment of neurological disorders and potential targets for the development of new drugs.

Hyperperfusion profiles after recanalization differentially associate with outcomes in a rat ischemic stroke model

Futile recanalization hampers prognoses of ischemic stroke after successful mechanical thrombectomy, hypothetically through post-recanalization perfusion deficits, onset-to-groin delays and sex effects. Clinically, acute multiparametric imaging studies remain challenging. We assessed possible relationships between these factors and disease outcome after experimental cerebral ischemia-reperfusion, using translational MRI, behavioral testing and multi-model inference analyses. Male and female rats (N = 60) were subjected to 45-/90-min filament-induced transient middle cerebral artery occlusion. Diffusion, T2- and perfusion-weighted MRI at occlusion, 0.5 h and four days after recanalization, enabled tracking of tissue fate, and relative regional cerebral blood flow (rrCBF) and -volume (rrCBV). Lesion areas were parcellated into core, salvageable tissue and delayed injury, verified by histology. Recanalization resulted in acute-to-subacute lesion volume reductions, most apparently in females (n = 19). Hyperacute normo-to-hyperperfusion in the post-ischemic lesion augmented towards day four, particularly in males (n = 23). Tissue suffering delayed injury contained higher ratios of hypoperfused voxels early after recanalization. Regressed against acute-to-subacute lesion volume change, increased rrCBF associated with lesion growth, but increased rrCBV with lesion reduction. Similar relationships were detected for behavioral outcome. Post-ischemic hyperperfusion may develop differentially in males and females, and can be beneficial or detrimental to disease outcome, depending on which perfusion parameter is used as explanatory variable.

Brain Maturation as a Fundamental Factor in Immune-Neurovascular Interactions in Stroke

Injuries in the developing brain cause significant long-term neurological deficits. Emerging clinical and preclinical data have demonstrated that the pathophysiology of neonatal and childhood stroke share similar mechanisms that regulate brain damage, but also have distinct molecular signatures and cellular pathways. The focus of this review is on two different diseases-neonatal and childhood stroke-with emphasis on similarities and distinctions identified thus far in rodent models of these diseases. This includes the susceptibility of distinct cell types to brain injury with particular emphasis on the role of resident and peripheral immune populations in modulating stroke outcome. Furthermore, we discuss some of the most recent and relevant findings in relation to the immune-neurovascular crosstalk and how the influence of inflammatory mediators is dependent on specific brain maturation stages. Finally, we comment on the current state of treatments geared toward inducing neuroprotection and promoting brain repair after injury and highlight that future prophylactic and therapeutic strategies for stroke should be age-specific and consider gender differences in order to achieve optimal translational success.

Bombyx batryticatus extract activates coagulation factor Ⅻ to promote angiogenesis in rats with cerebral ischemia/reperfusion injury

ETHNOPHARMACOLOGICAL RELEVANCE

Bombyx batryticatus is traditionally used to treat patients with stroke, but its mechanism remains unclear.

AIM OF THE STUDY

To explore the interventional effect of Bombyx batryticatus extract as an activator of FⅫ on angiogenesis of rats with cerebral ischemia/reperfusion injury.

MATERIALS AND METHODS

Firstly, the mechanism of Bombyx batryticatus interfering with IS was predicted by systematic pharmacology method, and then it was further verified by animal experiments. The effects of Bombyx batryticatus extract on plasma coagulation were detected, and the activation of coagulation factor Ⅻ (FⅫ) and its downstream substrate kallikrein kinase (KK) was detected in vitro. The brain morphology and expressions of FXII, KK, vascular endothelial growth factors (VEGF), CD31, Brdu/von Willebrand Factor (vWF) were detected. The morphological changes, cell proliferation and VEGF expression of brain microvascular endothelial cells were detected by oxygen glucose deprivation model. The pharmacodynamic substances of Bombyx batryticatus extract were identified by Liquid Chromatography - Mass Spectrometry (LC-MS).

RESULTS

The results of systematic pharmacology found that the treatment of IS by Bombyx batryticatus may be related to blood coagulation and other processes. In vitro, Bombyx batryticatus extract prolonged the activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT) (P < 0.05), activated FⅫ and promoted the production of downstream substrate KK, with dose-dependent (P < 0.05). Bombyx batryticatus extract improved the neuronal damage of rats, activated FXII and increased the production of KK and the expressions of VEGF, CD31, Brdu/vWF (P < 0.05). Bombyx batryticatus extract also increased the proliferation of brain microvascular endothelial cells and expression of VEGF in rats (P < 0.05). A total of 809 metabolites in Bombyx batryticatus extract were identified by LC-MS.

CONCLUSION

Bombyx batryticatus extract may ameliorate the injury of nerve function in rats with cerebral ischemia/reperfusion injury.

Understanding mechanistic aspect of the therapeutic role of herbal agents on neuroplasticity in cerebral ischemic-reperfusion injury

ETHNOPHARMACOLOGICAL RELEVANCE

Stroke is one of the leading causes of death and disability. The only FDA-approved therapy for treating stroke is tissue plasminogen activator (tPA), exhibiting a short therapeutic window. Due to this reason, only a small number of patients can be benefitted in this critical period. In addition, the use of endovascular interventions may reverse vessel occlusion more effectively and thus help further improve outcomes in experimental stroke. During recovery of blood flow after ischemia, patients experience cognitive, behavioral, affective, emotional, and electrophysiological changes. Therefore, it became the need for an hour to discover a novel strategy for managing stroke. The drug discovery process has focused on developing herbal medicines with neuroprotective effects via modulating neuroplasticity.

AIM OF THE STUDY

We gather and highlight the most essential traditional understanding of therapeutic plants and their efficacy in cerebral ischemia-reperfusion injury. In addition, we provide a concise summary and explanation of herbal drugs and their role in improving neuroplasticity. We review the pharmacological activity of polyherbal formulations produced from some of the most frequently referenced botanicals for the treatment of cerebral ischemia damage.

MATERIALS AND METHODS

A systematic literature review of bentham, scopus, pubmed, medline, and embase (elsevier) databases was carried out with the help of the keywords like neuroplasticity, herbal drugs, neural progenitor cells, neuroprotection, stem cells. The review was conducted using the above keywords to understand the therapeutic and mechanistic role of herbal neuroprotective agents on neuroplasticity in cerebral ischemic-reperfusion injury.

RESULTS

Neuroplasticity emerged as an alternative to improve recovery and management after cerebral ischemic reperfusion injury. Neuroplasticity is a physiological process throughout one's life in response to any stimuli and environment. Traditional herbal medicines have been established as an adjuvant to stroke therapy since they were used from ancient times and provided promising effects as an adjuvant to experimental stroke. The plants and phytochemicals such as Curcuma longa L., Moringa oliefera Lam, Panax ginseng C.A. Mey., and Rehmannia glutinosa (Gaertn.) DC., etc., have shown promising effects in improving neuroplasticity after experimental stroke. Such effects occur by modulation of various molecular signalling pathways, including PI3K/Akt, BDNF/CREB, JAK/STAT, HIF-1α/VEGF, etc. CONCLUSIONS: Here, we gave a perspective on plant species that have shown neuroprotective effects and can show promising results in promoting neuroplasticity with specific targets after cerebral ischemic reperfusion injury. In this review, we provide the complete detail of studies conducted on the role of herbal drugs in improving neuroplasticity and the signaling pathway involved in the recovery and management of experimental stroke.

Il1r2 and Tnfrsf12a in transcranial magnetic stimulation effect of ischemic stroke via bioinformatics analysis

Ischemic stroke refers to ischemic necrosis or softening of localized brain tissue. Transcranial magnetic stimulation (TMS) is a painless, noninvasive and green treatment method, which acts on the central nervous system through a pulsed magnetic field to assist in the treatment of central nervous system injury diseases. However, the role of Il1r2 and Tnfrsf12a in this is unknown. The ischemic stroke datasets GSE81302 and TMS datasets GSE230148 were downloaded from Gene Expression Omnibus database. Differentially expressed genes (DEGs) were screened and weighted gene co-expression network analysis (WGCNA) was performed. The construction and analysis of protein-protein interaction (PPI) network and functional enrichment analysis were performed. Draw heat map gene expression. Through the Comparative Toxicogenomics Database (CTD) to find the most relevant and core gene diseases. TargetScan was used to screen miRNAs regulating DEGs. A total of 39 DEGs were identified. According to gene ontology (GO) analysis results, in biological process (BP) analysis, they were mainly enriched in the positive regulation of apoptosis process, inflammatory response, positive regulation of p38MAPK cascade, and regulation of cell cycle. In cellular component (CC) analysis, they were mainly enriched in the cell surface, cytoplasm, and extracellular space. In Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, they were mainly enriched in nf-κB signaling pathway, fluid shear stress and atherosclerosis, P53 signaling pathway, TNF signaling pathway, and apoptosis. Among the enrichment items of metascape, negative regulation of T cell activation, hematopoietic cell lineage, positive regulation of apoptotic process, fluid shear stress and atherosclerosis were observed in GO enrichment items. Five core genes (Socs3, Irf1, Il1r2, Ccr1, and Tnfrsf12a) were obtained, which were highly expressed in ischemic stroke samples. Il1r2 and Tnfrsf12a were lowly expressed in TMS samples. CTD analysis found that the core gene (Socs3, Irf1 and Il1r2, Ccr1, Tnfrsf12a) and ischemic stroke, atherosclerosis, hypertension, hyperlipidemia, thrombosis, stroke, myocardial ischemia, myocardial infarction, and inflammation. Il1r2 and Tnfrsf12a are highly expressed in ischemic stroke, but lowly expressed in TMS samples.

Spinal Cord Injury: From MicroRNAs to Exosomal MicroRNAs

Spinal cord injury (SCI) is an unfortunate experience that may generate extensive sensory and motor disabilities due to the destruction and passing of nerve cells. MicroRNAs are small RNA molecules that do not code for proteins but instead serve to regulate protein synthesis by targeting messenger RNA's expression. After SCI, secondary damage like apoptosis, oxidative stress, inflammation, and autophagy occurs, and differentially expressed microRNAs show a function in these procedures. Almost all animal and plant cells release exosomes, which are sophisticated formations of lipid membranes. These exosomes have the capacity to deliver significant materials, such as proteins, RNAs and lipids, to cells in need, regulating their functions and serving as a way of communication. This new method offers a fresh approach to treating spinal cord injury. Obviously, the exosome has the benefit of conveying the transported material across performing regulatory activities and the blood-brain barrier. Among the exosome cargoes, microRNAs, which modulate their mRNA targets, show considerable promise in the pathogenic diagnosis, process, and therapy of SCI. Herein, we describe the roles of microRNAs in SCI. Furthermore, we emphasize the importance of exosomal microRNAs in this disease.

Expression, Functional Polymorphism, and Diagnostic Values of MIAT rs2331291 and H19 rs217727 Long Non-Coding RNAs in Cerebral Ischemic Stroke Egyptian Patients

Cerebral ischemic stroke (CIS) is a severe cerebral vascular event. This research aimed to evaluate the role of single-nucleotide polymorphisms (SNPs) of the lncRNAs MIAT rs2331291 and H19 rs217727 and epigenetic methylation in the expression patterns of serum lncRNA H19 in CIS Egyptian patients. It included 80 CIS cases and 40 healthy subjects. Serum MIAT expression levels decreased, whereas serum H19 expression levels increased among CIS compared to controls. For MIAT rs2331291, there were significant differences in the genotypic and allelic frequencies between the CIS and healthy subjects at p = 0.02 and p = 0.0001, respectively. Our findings illustrated a significantly increased MIAT T/T genotype frequency in hypertensive CIS compared to non-hypertensive CIS at p = 0.004. However, H19 rs217727 gene frequency C/C was not significantly higher in non-hypertensive CIS than in hypertensive CIS. The methylation of the H19 gene promoter was significantly higher in CIS patients compared to healthy subjects. The level of MIAT was positively correlated with serum H19 in CIS. Receiver operating characteristics (ROC) analysis revealed that serum MIAT and H19 have a high diagnostic potential for distinguishing CIS subjects from healthy ones. In conclusion, the MIAT-rs2331291 polymorphism might serve as a novel potential indicator of CIS.

Transcription Factor EB: A Promising Therapeutic Target for Ischemic Stroke

Transcription factor EB (TFEB) is an important endogenous defensive protein that responds to ischemic stimuli. Acute ischemic stroke is a growing concern due to its high morbidity and mortality. Most survivors suffer from disabilities such as numbness or weakness in an arm or leg, facial droop, difficulty speaking or understanding speech, confusion, impaired balance or coordination, or loss of vision. Although TFEB plays a neuroprotective role, its potential effect on ischemic stroke remains unclear. This article describes the basic structure, regulation of transcriptional activity, and biological roles of TFEB relevant to ischemic stroke. Additionally, we explore the effects of TFEB on the various pathological processes underlying ischemic stroke and current therapeutic approaches. The information compiled here may inform clinical and basic studies on TFEB, which may be an effective therapeutic drug target for ischemic stroke.

From diabetic hyperglycemia to cerebrovascular Damage: A narrative review

Diabetes mellitus is a globally significant disease that can lead to systemic complications, particularly vascular damage, including cardiovascular and cerebrovascular diseases of relevance. The physiological changes resulting from the imbalance in blood glucose levels play a crucial role in initiating vascular endothelial damage. Elevated glucose levels can also penetrate the central nervous system, triggering diabetic encephalopathy characterized by oxidative damage to brain components and activation of alternative and neurotoxic pathways. This brain damage increases the risk of ischemic stroke, a leading cause of mortality worldwide and a major cause of disability among surviving patients. The aim of this review is to highlight important pathways related to hyperglycemic damage that extend to the brain and result in vascular dysfunction, ultimately leading to the occurrence of a stroke. Understanding how diabetes mellitus contributes to the development of ischemic stroke and its impact on patient outcomes is crucial for implementing therapeutic strategies that reduce the incidence of diabetes mellitus and its complications, ultimately decreasing morbidity and mortality associated with the disease.

Research progress on the regulation and mechanism of borneol on the blood-brain barrier in pathological states: a narrative review focused on ischemic stroke and cerebral glioma

Background and Objective

The blood-brain barrier (BBB) serves as a dynamic, selective shield, safeguarding the central nervous system (CNS) by separating the brain from circulating blood, preserving its microenvironment, and ensuring stability. However, in the presence of brain pathology, drug delivery across the BBB and blood-tumor barrier (BTB) becomes challenging, hindering effective treatments. Borneol exhibits promise in bidirectionally modulating the BBB under pathological conditions, suggesting at potential clinical applications for related diseases. Our primary goal in this review is to investigate borneol's potential clinical utility in bidirectionally regulating the BBB under pathological conditions.

Methods

The PubMed database, CNKI (China National Knowledge Infrastructure), Wanfang Data were searched to retrieve articles on animal experiments and cell-based research published from January 1, 2003, to May 1, 2023, using the following medical subject headings (MeSH) terms: borneol, blood-brain barrier, ischemic stroke, cerebral gliomas, anti-inflammatory. The search was limited to articles published in English and Chinese. In total, 86 articles were deemed eligible for inclusion in this study.

Key Content and Findings

The breakdown of the BBB is a key pathological process in ischemic stroke and cerebral glioma. When used alone, the lipophilic properties of borneol can reduce the permeability of the BBB and restore its normal function, thereby repairing brain damage and protecting brain tissue. Its specific protective effects may be related to inflammatory regulation mechanisms. The anti-inflammatory and protective effects of borneol can be used to improve and treat lesions caused by ischemic stroke and cerebral glioma. Furthermore, when combined with other drugs, borneol can accelerate the opening of the BBB, improve permeability through physiological processes, and enhance drug penetration and distribution in the brain without causing pathological damage to the brain.

Conclusions

This review summarizes the mechanisms by which borneol regulates the BBB and BTB in ischemic stroke and cerebral glioma, and discusses the potential clinical applications of borneol in the treatment of these diseases. It is believed that in the future, as research methods are refined, more effective and targeted therapies for cerebral glioma and ischemic stroke will be explored related to the protective mechanism of the BBB under pathological conditions with borneol alone or in combination with other drugs.

Mechanisms of Cadmium Neurotoxicity

Cadmium is a heavy metal that increasingly contaminates food and drink products. Once ingested, cadmium exerts toxic effects that pose a significant threat to human health. The nervous system is particularly vulnerable to prolonged, low-dose cadmium exposure. This review article provides an overview of cadmium's primary mechanisms of neurotoxicity. Cadmium gains entry into the nervous system via zinc and calcium transporters, altering the homeostasis for these metal ions. Once within the nervous system, cadmium disrupts mitochondrial respiration by decreasing ATP synthesis and increasing the production of reactive oxygen species. Cadmium also impairs normal neurotransmission by increasing neurotransmitter release asynchronicity and disrupting neurotransmitter signaling proteins. Cadmium furthermore impairs the blood-brain barrier and alters the regulation of glycogen metabolism. Together, these mechanisms represent multiple sites of biochemical perturbation that result in cumulative nervous system damage which can increase the risk for neurological and neurodegenerative disorders. Understanding the way by which cadmium exerts its effects is critical for developing effective treatment and prevention strategies against cadmium-induced neurotoxic insult.

Stronger influence of systemic than local hemodynamic-vascular factors on resting-state BOLD functional connectivity

Correlated fluctuations in the blood oxygenation level dependent (BOLD) signal of resting-state functional MRI (i.e., BOLD-functional connectivity, BOLD-FC) reflect a spectrum of neuronal and non-neuronal processes. In particular, there are multiple hemodynamic-vascular influences on BOLD-FC on both systemic (e.g., perfusion delay) and local levels (e.g., neurovascular coupling). While the influence of individual factors has been studied extensively, combined and comparative studies of systemic and local hemodynamic-vascular factors on BOLD-FC are scarce, notably in humans. We employed a multi-modal MRI approach to investigate and compare distinct hemodynamic-vascular processes and their impact on homotopic BOLD-FC in healthy controls and patients with unilateral asymptomatic internal carotid artery stenosis (ICAS). Asymptomatic ICAS is a cerebrovascular disorder, in which neuronal functioning is largely preserved but hemodynamic-vascular processes are impaired, mostly on the side of stenosis. Investigated indicators for local hemodynamic-vascular processes comprise capillary transit time heterogeneity (CTH) and cerebral blood volume (CBV) from dynamic susceptibility contrast (DSC) MRI, and cerebral blood flow (CBF) from pseudo-continuous arterial spin labeling (pCASL). Indicators for systemic processes are time-to-peak (TTP) from DSC MRI and BOLD lags from functional MRI. For each of these parameters, their influence on BOLD-FC was estimated by a comprehensive linear mixed model. Equally across groups, we found that individual mean BOLD-FC, local (CTH, CBV, and CBF) and systemic (TTP and BOLD lag) hemodynamic-vascular factors together explain 40.7% of BOLD-FC variance, with 20% of BOLD-FC variance explained by hemodynamic-vascular factors, with an about two-times larger contribution of systemic versus local factors. We conclude that regional differences in blood supply, i.e., systemic perfusion delays, exert a stronger influence on BOLD-FC than impairments in local neurovascular coupling.

Research progress on the roles of neurovascular unit in stroke-induced immunosuppression

A complex pathophysiological mechanism is involved in brain injury following cerebral infarction. The neurovascular unit (NVU) is a complex multi-cellular structure consisting of neurons, endothelial cells, pericyte, astrocyte, microglia and extracellular matrix, etc. The dyshomeostasis of NVU directly participates in the regulation of inflammatory immune process. The components of NVU promote inflammatory overreaction and synergize with the overactivation of autonomic nervous system to initiate stroke-induced immunodepression (SIID). SIID can alleviate the damage caused by inflammation, however, it also makes stroke patients more susceptible to infection, leading to systemic damage. This article reviews the mechanism of SIID and the roles of NVU in SIID, to provide a perspective for reperfusion, prognosis and immunomodulatory therapy of cerebral infarction.

The Role and Therapeutic Implications of Inflammation in the Pathogenesis of Brain Arteriovenous Malformations

Brain arteriovenous malformations (bAVMs) are focal vascular lesions composed of abnormal vascular channels without an intervening capillary network. As a result, high-pressure arterial blood shunts directly into the venous outflow system. These high-flow, low-resistance shunts are composed of dilated, tortuous, and fragile vessels, which are prone to rupture. BAVMs are a leading cause of hemorrhagic stroke in children and young adults. Current treatments for bAVMs are limited to surgery, embolization, and radiosurgery, although even these options are not viable for ~20% of AVM patients due to excessive risk. Critically, inflammation has been suggested to contribute to lesion progression. Here we summarize the current literature discussing the role of the immune system in bAVM pathogenesis and lesion progression, as well as the potential for targeting inflammation to prevent bAVM rupture and intracranial hemorrhage. We conclude by proposing that a dysfunctional endothelium, which harbors the somatic mutations that have been shown to give rise to sporadic bAVMs, may drive disease development and progression by altering the immune status of the brain.

Neuronal Zinc Transporter ZnT3 Modulates Cerebral Ischemia-Induced Blood-Brain Barrier Disruption

Zinc plays important roles in both physiological and pathological processes in the brain. Accumulation of free zinc in ischemic tissue is recognized to contribute to blood-brain barrier (BBB) disruption following cerebral ischemia, but little is known either about the source of free zinc in microvessels or the mechanism by which free zinc mediates ischemia-induced BBB damage. We utilized cellular and animal models of ischemic stroke to determine the source of high levels of free zinc and the mechanism of free zinc-mediated BBB damage after ischemia. We report that cerebral ischemia elevated the level of extracellular fluid (ECF-Zn) of ischemic brain, leading to exacerbated BBB damage in a rat stroke model. Specifically suppressing zinc release from neurons, utilizing neuronal-specific zinc transporter 3 (ZnT3) knockout mice, markedly reduced ECF-Zn and BBB permeability after ischemia. Intriguingly, the activity of zinc-dependent metalloproteinase-2 (MMP-2) was modulated by ECF-Zn levels. Elevated ECF-Zn during ischemia directly bound to MMP-2 in extracellular fluid, increased its zinc content and augmented MMP-2 activity, leading to the degradation of tight junction protein in cerebral microvessels and BBB disruption. These findings suggest the role of neuronal ZnT3 in modulating ischemia-induced BBB disruption and reveal a novel mechanism of MMP-2 activation in BBB disruption after stroke, demonstrating ZnT3 as an effective target for stroke treatment.

Mitochondrial transport in neurons and evidence for its involvement in acute neurological disorders

Ensuring mitochondrial quality is essential for maintaining neuronal homeostasis, and mitochondrial transport plays a vital role in mitochondrial quality control. In this review, we first provide an overview of neuronal mitochondrial transport, followed by a detailed description of the various motors and adaptors associated with the anterograde and retrograde transport of mitochondria. Subsequently, we review the modest evidence involving mitochondrial transport mechanisms that has surfaced in acute neurological disorders, including traumatic brain injury, spinal cord injury, spontaneous intracerebral hemorrhage, and ischemic stroke. An in-depth study of this area will help deepen our understanding of the mechanisms underlying the development of various acute neurological disorders and ultimately improve therapeutic options.

Intermittent hypoxia protects against hypoxic-ischemic brain damage by inducing functional angiogenesis

Ischemic stroke (IS) induces neurological damage due to cerebrovascular occlusion. Restoring blood perfusion to the ischemic brain area in a timely fashion is the most effective treatment strategy. Hypoxia is an effective way of restoring blood perfusion by improving cerebrovascular microcirculation, while the effect varies greatly depending on hypoxic mode. This study aimed to screen for the optimal hypoxic mode to improve cerebrovascular microcirculation and prevent IS. Here, we found that compared with continuous hypoxia (CH), intermittent hypoxia (IH) significantly improved cerebral blood flow and oxygen saturation in mice without causing neurological impairment. By analyzing cerebrovascular microcirculation from mice, we found that the IH mode (13%, 5*10) with 13% O2, 5 min interval, and 10 cycles per day significantly improved the cerebrovascular microcirculation by promoting angiogenesis without affecting the integrity of the blood-brain barrier. In addition, IH (13%, 5*10) treatment of distal middle cerebral artery occlusion (dMCAO) mice significantly alleviated neurological dysfunction and reduced cerebral infarct volume by improving cerebrovascular microcirculation. CH had none of these positive effects. In summary, our study screened for an appropriate intermittent hypoxic mode that could improve cerebrovascular microcirculation, laying a theoretical foundation for the prevention and treatment of IS in clinical practice.

Astrocyte-Neuronal Communication and Its Role in Stroke

Astrocytes are the most abundant glial cells in the central nervous system. These cells are an important hub for intercellular communication. They participate in various pathophysiological processes, including synaptogenesis, metabolic transformation, scar production, and blood-brain barrier repair. The mechanisms and functional consequences of astrocyte-neuron signaling are more complex than previously thought. Stroke is a disease associated with neurons in which astrocytes also play an important role. Astrocytes respond to the alterations in the brain microenvironment after stroke, providing required substances to neurons. However, they can also have harmful effects. In this review, we have summarized the function of astrocytes, their association with neurons, and two paradigms of the inflammatory response, which suggest that targeting astrocytes may be an effective strategy for treating stroke.

The neurovascular unit in healthy and injured spinal cord

The neurovascular unit (NVU) reflects the close temporal and spatial link between neurons and blood vessels. However, the understanding of the NVU in the spinal cord is far from clear and largely based on generalized knowledge obtained from the brain. Herein, we review the present knowledge of the NVU and highlight candidate approaches to investigate the NVU, particularly focusing on the spinal cord. Several unique features maintain the highly regulated microenvironment in the NVU. Autoregulation and neurovascular coupling ensure regional blood flow meets the metabolic demand according to the blood supply or local neural activation. The blood-central nervous system barrier partitions the circulating blood from neural parenchyma and facilitates the selective exchange of substances. Furthermore, we discuss spinal cord injury (SCI) as a common injury from the perspective of NVU dysfunction. Hopefully, this review will help expand the understanding of the NVU in the spinal cord and inspire new insights into SCI.

Mono-(2-ethylhexyl)-phthalate potentiates methylglyoxal-induced blood-brain barrier damage via mitochondria-derived oxidative stress and bioenergetic perturbation

Phthalates in contaminated foods and personal care products are one of the most frequently exposed chemicals with a public health concern. Phthalate exposure is related to cardiovascular diseases, including diabetic vascular complications and cerebrovascular diseases, yet the mechanism is still unclear. The blood-brain barrier (BBB) integrity disruption is strongly associated with cardiovascular and neurological disease exacerbation. We investigated BBB damage by di-(2-ethylhexyl) phthalate (DEHP) or its metabolite mono-(2-ethylhexyl) phthalate (MEHP) using brain endothelial cells and rat models. BBB damage by the subthreshold level of MEHP, but not a DEHP, significantly increased by the presence of methylglyoxal (MG), a reactive dicarbonyl compound whose levels increase in the blood in hyperglycemic conditions in diabetic patients. Significant potentiation in apoptosis and autophagy activation, mitochondria-derived reactive oxygen species (ROS) production, and mitochondrial metabolic disturbance were observed in brain ECs by co-exposure to MG and MEHP. N-acetyl cysteine (NAC) restored autophagy activation as well as tight junction protein impairment induced by co-exposure to MG and MEHP. Intraperitoneal administration of MG and MEHP significantly altered mitochondrial membrane potential and tight junction integrity in rat brain endothelium. This study may provide novel insights into enhancing phthalate toxicity in susceptible populations, such as diabetic patients.

Sirtuins: Promising Therapeutic Targets to Treat Ischemic Stroke

Stroke is a major cause of mortality and disability globally, with ischemic stroke (IS) accounting for over 80% of all stroke cases. The pathological process of IS involves numerous signal molecules, among which are the highly conserved nicotinamide adenine dinucleotide (NAD+)-dependent enzymes known as sirtuins (SIRTs). SIRTs modulate various biological processes, including cell differentiation, energy metabolism, DNA repair, inflammation, and oxidative stress. Importantly, several studies have reported a correlation between SIRTs and IS. This review introduces the general aspects of SIRTs, including their distribution, subcellular location, enzyme activity, and substrate. We also discuss their regulatory roles and potential mechanisms in IS. Finally, we describe the current therapeutic methods based on SIRTs, such as pharmacotherapy, non-pharmacological therapeutic/rehabilitative interventions, epigenetic regulators, potential molecules, and stem cell-derived exosome therapy. The data collected in this study will potentially contribute to both clinical and fundamental research on SIRTs, geared towards developing effective therapeutic candidates for future treatment of IS.

New insights into the roles of oligodendrocytes regulation in ischemic stroke recovery

Oligodendrocytes (OLs), the myelin-forming cells of the central nervous system, are integral to axonal integrity and function. Hypoxia-ischemia episodes can cause severe damage to these vulnerable cells through excitotoxicity, oxidative stress, inflammation, and mitochondrial dysfunction, leading to axonal dystrophy, neuronal dysfunction, and neurological impairments. OLs damage can result in demyelination and myelination disorders, severely impacting axonal function, structure, metabolism, and survival. Adult-onset stroke, periventricular leukomalacia, and post-stroke cognitive impairment primarily target OLs, making them a critical therapeutic target. Therapeutic strategies targeting OLs, myelin, and their receptors should be given more emphasis to attenuate ischemia injury and establish functional recovery after stroke. This review summarizes recent advances on the function of OLs in ischemic injury, as well as the present and emerging principles that serve as the foundation for protective strategies against OL deaths.

Tocotrienol-Rich Fraction Ameliorates the Aluminium Chloride-Induced Neurovascular Dysfunction-Associated Vascular Dementia in Rats

Neurovascular dysfunction leads to the second most common type of dementia, i.e., vascular dementia (VaD). Toxic metals, such as aluminium, increase the risk of neurovascular dysfunction-associated VaD. Hence, we hypothesized that a natural antioxidant derived from palm oil, i.e., tocotrienol-rich fraction (TRF), can attenuate the aluminium chloride (AlCl₃)-induced VaD in rats. Rats were induced with AlCl₃ (150 mg/kg) intraperitoneally for seven days followed by TRF treatment for twenty-one days. The elevated plus maze test was performed for memory assessment. Serum nitrite and plasma myeloperoxidase (MPO) levels were measured as biomarkers for endothelial dysfunction and small vessel disease determination. Thiobarbituric acid reactive substance (TBARS) was determined as brain oxidative stress marker. Platelet-derived growth factor-C (PDGF-C) expression in the hippocampus was identified using immunohistochemistry for detecting the neovascularisation process. AlCl₃ showed a significant decrease in memory and serum nitrite levels, while MPO and TBARS levels were increased; moreover, PDGF-C was not expressed in the hippocampus. However, TRF treatment significantly improved memory, increased serum nitrite, decreased MPO and TBARS, and expressed PDGF-C in hippocampus. Thus, the results imply that TRF reduces brain oxidative stress, improves endothelial function, facilitates hippocampus PDGF-C expression for neovascularisation process, protects neurons, and improves memory in neurovascular dysfunction-associated VaD rats.

Stroke by inducing HDAC9-dependent deacetylation of HIF-1 and Sp1, promotes TfR1 transcription and GPX4 reduction, thus determining ferroptotic neuronal death

Background: The inhibition of histone deacetylase 9 (HDAC9) represents a promising druggable target for stroke intervention. Indeed, HDAC9 is overexpressed in neurons after brain ischemia where exerts a neurodetrimental role. However, mechanisms of HDAC9-dependent neuronal cell death are not yet well established. Methods: Brain ischemia was obtained in vitro by primary cortical neurons exposed to glucose deprivation plus reoxygenation (OGD/Rx) and in vivo by transient middle cerebral artery occlusion. Western blot and quantitative real-time polymerase chain reaction were used to evaluate transcript and protein levels. Chromatin immunoprecipitation was used to evaluate the binding of transcription factors to the promoter of target genes. Cell viability was measured by MTT and LDH assays. Ferroptosis was evaluated by iron overload and 4-hydroxynonenal (4-HNE) release. Results: Our results showed that HDAC9 binds to hypoxia-inducible factor 1 (HIF-1) and specificity protein 1 (Sp1), two transcription activators of transferrin 1 receptor (TfR1) and glutathione peroxidase 4 (GPX4) genes, respectively, in neuronal cells exposed to OGD/Rx. Consequently, HDAC9 induced: (1) an increase in protein level of HIF-1 by deacetylation and deubiquitination, thus promoting the transcription of the pro-ferroptotic TfR1 gene; and (2) a reduction in Sp1 protein levels by deacetylation and ubiquitination, thus resulting in a down-regulation of the anti-ferroptotic GPX4 gene. Supporting these results, the silencing of HDAC9 partially prevented either HIF-1 increase and Sp1 reduction after OGD/Rx. Interestingly, silencing of the neurodetrimental factors, HDAC9, HIF-1, or TfR1 or the overexpression of the prosurvival factors Sp1 or GPX4 significantly reduced a well-known marker of ferroptosis 4-HNE after OGD/Rx. More important, in vivo, intracerebroventricular injection of siHDAC9 reduced 4-HNE levels after stroke by preventing: (1) HIF-1 and TfR1 increase and thus the augmented intracellular iron overload; and (2) a reduction of Sp1 and its target gene GPX4. Conclusions: Collectively, results obtained suggest that HDAC9 mediates post-traslational modifications of HIF-1 and Sp1 that, in turn, increases TfR1 and decreases GPX4 expression, thus promoting neuronal ferroptosis in in vitro and in vivo models of stroke.

The central role of peripheral inflammation in ischemic stroke

Stroke pathology and its treatments conventionally focus on the brain. Probing inflammation, a critical secondary cell death mechanism in stroke, has been largely relegated to the brain. To this end, peripheral inflammation has emerged as an equally potent contributor to the onset and progression of stroke secondary cell death. Here, we review novel concepts on peripheral organs displaying robust inflammatory response to stroke. These inflammation-plagued organs include the spleen, cervical lymph nodes, thymus, bone marrow, gastrointestinal system, and adrenal glands, likely converging their inflammatory effects through B and T-cells. Recognizing the significant impact of this systemic inflammation, we also discuss innovative stroke therapeutics directed at sequestration of peripheral inflammation. This review paper challenges the paradigm of a brain-centered disease pathology and treatment and offers a peripheral approach to our stroke understanding.

Functional genomics in stroke: current and future applications of iPSCs and gene editing to dissect the function of risk variants

Stroke is an important disease with unmet clinical need. To uncover novel paths for treatment, it is of critical importance to develop relevant laboratory models that may help to shed light on the pathophysiological mechanisms of stroke. Induced pluripotent stem cells (iPSCs) technology has enormous potential to advance our knowledge into stroke by creating novel human models for research and therapeutic testing. iPSCs models generated from patients with specific stroke types and specific genetic predisposition in combination with other state of art technologies including genome editing, multi-omics, 3D system, libraries screening, offer the opportunity to investigate disease-related pathways and identify potential novel therapeutic targets that can then be tested in these models. Thus, iPSCs offer an unprecedented opportunity to make rapid progress in the field of stroke and vascular dementia research leading to clinical translation. This review paper summarizes some of the key areas in which patient-derived iPSCs technology has been applied to disease modelling and discusses the ongoing challenges and the future directions for the application of this technology in the field of stroke research.

Non-genomic Effect of Estradiol on the Neurovascular Unit and Possible Involvement in the Cerebral Vascular Accident

Cerebrovascular diseases, such as ischemic cerebral vascular accident (CVA), are responsible for causing high rates of morbidity, mortality, and disability in the population. The neurovascular unit (NVU) during and after ischemic CVA plays crucial roles in cell regulation and preservation, the immune and inflammatory response, and cell and/or tissue survival and repair. Cellular responses to 17β-estradiol (E2) can be triggered by two mechanisms: one called classical or genomic, which is due to the activation of the "classical" nuclear estrogen receptors α (ERα) and β (ERβ), and the non-genomic or rapid mechanism, which is due to the activation of the G protein-coupled estrogen receptor 1 (GPER) that is located in the plasma membrane and some in intracellular membranes, such as in the Golgi apparatus and endoplasmic reticulum. Nuclear receptors can regulate gene expression and cellular functions. On the contrary, activating the GPER by E2 and/or its G-1 agonist triggers several rapid cell signaling pathways. Therefore, E2 or its G-1 agonist, by mediating GPER activation and/or expression, can influence several NVU cell types. Most studies argue that the activation of the GPER may be used as a potential therapeutic target in various pathologies, such as CVA. Thus, with this review, we aimed to summarize the existing literature on the role of GPER mediated by E2 and/or its agonist G-1 in the physiology and pathophysiology of NVU.

Oral Treatment with the Extract of Euterpe oleracea Mart. Improves Motor Dysfunction and Reduces Brain Injury in Rats Subjected to Ischemic Stroke

Ischemic stroke is one of the principal causes of morbidity and mortality around the world. The pathophysiological mechanisms that lead to the formation of the stroke lesions range from the bioenergetic failure of the cells and the intense production of reactive oxygen species to neuroinflammation. The fruit of the açaí palm, Euterpe oleracea Mart. (EO), is consumed by traditional populations in the Brazilian Amazon region, and it is known to have antioxidant and anti-inflammatory properties. We evaluated whether the clarified extract of EO was capable of reducing the area of lesion and promoting neuronal survival following ischemic stroke in rats. Animals submitted to ischemic stroke and treated with EO extract presented a significant improvement in their neurological deficit from the ninth day onward. We also observed a reduction in the extent of the cerebral injury and the preservation of the neurons of the cortical layers. Taken together, our findings indicate that treatment with EO extract in the acute phase following a stroke can trigger signaling pathways that culminate in neuronal survival and promote the partial recovery of neurological scores. However, further detailed studies of the intracellular signaling pathways are needed to better understand the mechanisms involved.

Vascular dysregulation in glaucoma: retinal vasoconstriction and normal neurovascular coupling in altitudinal visual field defects

Purpose

Vision loss in glaucoma is not only associated with elevated intraocular pressure and neurodegeneration, but vascular dysregulation (VD) is a major factor. To optimize therapy, an improved understanding of concepts of predictive, preventive, and personalized medicine (3PM) is needed which is based on a more detailed understanding of VD pathology. Specifically, to learn if the root cause of glaucomatous vision loss is of neuronal (degeneration) or vascular origin, we now studied neurovascular coupling (NVC) and vessel morphology and their relationship to vision loss in glaucoma.

Methods

In patients with primary open angle glaucoma (POAG) (n = 30) and healthy controls (n = 22), NVC was studied using dynamic vessel analyzer to quantify retinal vessel diameter before, during, and after flicker light stimulation to evaluate the dilation response following neuronal activation. Vessel features and dilation were then related to branch level and visual field impairment.

Results

Retinal arterial and venous vessels had significantly smaller diameters in patients with POAG in comparison to controls. However, both arterial and venous dilation reached normal values during neuronal activation despite their smaller diameters. This was largely independent of visual field depth and varied among patients.

Conclusions

Because dilation/constriction is normal, VD in POAG can be explained by chronic vasoconstriction which limits energy supply to retinal (and brain) neurons with subsequent hypo-metabolism ("silent" neurons) or neuronal cell death. We propose that the root cause of POAG is primarily of vascular and not neuronal origin. This understanding can help to better personalize POAG therapy of not only targeting eye pressure but also vasoconstriction to prevent low vision, slowing its progression and supporting recovery and restoration.

Trial registration

ClinicalTrials.gov, # NCT04037384 on July 3, 2019.

MicroRNAs in spinal cord injury: A narrative review

Spinal cord injury (SCI) is a global medical problem with high disability and mortality rates. At present, the diagnosis and treatment of SCI are still lacking. Spinal cord injury has a complex etiology, lack of diagnostic methods, poor treatment effect and other problems, which lead to the difficulty of spinal cord regeneration and repair, and poor functional recovery. Recent studies have shown that gene expression plays an important role in the regulation of SCI repair. MicroRNAs (miRNAs) are non-coding RNA molecules that target mRNA expression in order to silence, translate, or interfere with protein synthesis. Secondary damage, such as oxidative stress, apoptosis, autophagy, and inflammation, occurs after SCI, and differentially expressed miRNAs contribute to these events. This article reviews the pathophysiological mechanism of miRNAs in secondary injury after SCI, focusing on the mechanism of miRNAs in secondary neuroinflammation after SCI, so as to provide new ideas and basis for the clinical diagnosis and treatment of miRNAs in SCI. The mechanisms of miRNAs in neurological diseases may also make them potential biomarkers and therapeutic targets for spinal cord injuries.

Perspective insights into hydrogels and nanomaterials for ischemic stroke

Ischemic stroke (IS) is a neurological disorder prevalent worldwide with a high disability and mortality rate. In the clinic setting, tissue plasminogen activator (tPA) and thrombectomy could restore blood flow of the occlusion region and improve the outcomes of IS patients; however, these therapies are restricted by a narrow time window. Although several preclinical trials have revealed the molecular and cellular mechanisms underlying infarct lesions, the translatability of most findings is unsatisfactory, which contributes to the emergence of new biomaterials, such as hydrogels and nanomaterials, for the treatment of IS. Biomaterials function as structural scaffolds or are combined with other compounds to release therapeutic drugs. Biomaterial-mediated drug delivery approaches could optimize the therapeutic effects based on their brain-targeting property, biocompatibility, and functionality. This review summarizes the advances in biomaterials in the last several years, aiming to discuss the therapeutic potential of new biomaterials from the bench to bedside. The promising prospects of new biomaterials indicate the possibility of an organic combination between materialogy and medicine, which is a novel field under exploration.