Ischemic cell death in brain neurons

Inhibition of the cGAS-STING pathway: contributing to the treatment of cerebral ischemia-reperfusion injury

The cGAS-STING pathway plays an important role in ischemia-reperfusion injury in the heart, liver, brain, and kidney, but its role and mechanisms in cerebral ischemia-reperfusion injury have not been systematically reviewed. Here, we outline the components of the cGAS-STING pathway and then analyze its role in autophagy, ferroptosis, cellular pyroptosis, disequilibrium of calcium homeostasis, inflammatory responses, disruption of the blood-brain barrier, microglia transformation, and complement system activation following cerebral ischemia-reperfusion injury. We further analyze the value of cGAS-STING pathway inhibitors in the treatment of cerebral ischemia-reperfusion injury and conclude that the pathway can regulate cerebral ischemia-reperfusion injury through multiple mechanisms. Inhibition of the cGAS-STING pathway may be helpful in the treatment of cerebral ischemia-reperfusion injury.

Exosomes: the next-generation therapeutic platform for ischemic stroke

Current therapeutic strategies for ischemic stroke fall short of the desired objective of neurological functional recovery. Therefore, there is an urgent need to develop new methods for the treatment of this condition. Exosomes are natural cell-derived vesicles that mediate signal transduction between cells under physiological and pathological conditions. They have low immunogenicity, good stability, high delivery efficiency, and the ability to cross the blood-brain barrier. These physiological properties of exosomes have the potential to lead to new breakthroughs in the treatment of ischemic stroke. The rapid development of nanotechnology has advanced the application of engineered exosomes, which can effectively improve targeting ability, enhance therapeutic efficacy, and minimize the dosages needed. Advances in technology have also driven clinical translational research on exosomes. In this review, we describe the therapeutic effects of exosomes and their positive roles in current treatment strategies for ischemic stroke, including their anti-inflammation, anti-apoptosis, autophagy-regulation, angiogenesis, neurogenesis, and glial scar formation reduction effects. However, it is worth noting that, despite their significant therapeutic potential, there remains a dearth of standardized characterization methods and efficient isolation techniques capable of producing highly purified exosomes. Future optimization strategies should prioritize the exploration of suitable isolation techniques and the establishment of unified workflows to effectively harness exosomes for diagnostic or therapeutic applications in ischemic stroke. Ultimately, our review aims to summarize our understanding of exosome-based treatment prospects in ischemic stroke and foster innovative ideas for the development of exosome-based therapies.

Multimodal Assessment of the Origin of Myoclonus in Lance-Adams Syndrome

BACKGROUND AND OBJECTIVES

Lance-Adams syndrome (LAS), or chronic posthypoxic myoclonus, is a long-term disabling neurologic disorder occurring in survivors of anoxia. The cortical or subcortical origin of this myoclonus is unclear. We aimed to identify the neuroanatomical origin of myoclonus in LAS.

METHODS

We conducted a cross-sectional study and investigated patients diagnosed with LAS from the Department of Neurology of Pitié-Salpêtrière Hospital, using multimodal neurologic explorations: EEG with quantitative analyses, polygraphic EMG recording of myoclonus, coupled EEG-EMG analyses with jerk-locked back averaging, and 18fluorodeoxyglucose PET/CT imaging.

RESULTS

All 18 patients had action multifocal or generalized myoclonus. Eleven patients also presented seizures, mainly generalized tonic-clonic seizures. For 8 patients, myoclonus decreased after seizures for a variable duration, from 1 day to 2 weeks. Epileptiform discharges were identified over the central median region (n = 14), with a maximal amplitude on the Cz (65 ± 20 µV, n = 12) and Fz (107 µV, n = 1) electrodes, and a significantly increased frequency during non-rapid eye movement sleep stages 1 (12 ± 8.5 events/minute, p = 0.004, n = 9) and 2 (11 ± 8.8 events/minute, p = 0.016, n = 7) compared with wake (5.5 ± 5.4 events/minute). The duration of the cortical and muscular events was significantly and positively correlated (ρ = 0.58, p < 0.001, n = 9). Action myoclonic jerks with a duration of <50 ms were confirmed in all patients, with a fast-descending corticospinal way organization with a mean biceps brachii-first interossei dorsalis delay of 9.8 ± 1 ms (n = 8). A central cortical transient preceding the muscular jerks was identified (n = 14), with a mean latency of -31.9 ± 2.9 ms for the tibialis anterior muscle (n = 7). A regional metabolism decrease was observed in the precentral cortex, supplementary motor area, paracentral lobule (n = 6), and postcentral cortex and precuneus (n = 5). This metabolism decrease was bilateral in the precentral cortex for 83% of the patients and in the postcentral cortex for 100%. Hypometabolism in the precentral, supplementary motor, and postcentral areas was confirmed with a voxelwise analysis (p < 10-3, n = 6).

DISCUSSION

Our findings, based on a large cohort of patients with LAS, strongly suggest a cortical myoclonus, originating within the motor cortex and related to epileptiform mechanisms.

Activation of the Nrf2/Keap1 signaling pathway mediates the neuroprotective effect of Perillyl alcohol against cerebral hypoxic-ischemic damage in neonatal rats

Neonatal hypoxic-ischemic encephalopathy (HIE) is a severe disease with a poor prognosis, whose clinical treatment is still limited to therapeutic hypothermia with limited efficacy. Perillyl alcohol (POH), a natural monoterpene found in various plant essential oils, has shown neuroprotective properties, though its effects on HIE are not well understood. This study investigates the neuroprotective effects of POH on HIE both in vitro and in vivo. We established an in vitro model using glucose deprivation and hypoxia/reperfusion (OGD/R) in PC12 cells, alongside an in vivo model via the modified Rice-Vannucci method. Results indicated that POH acted as an indirect antioxidant, reducing inducible nitric oxide synthase and malondialdehyde production, maintaining content of antioxidant molecules and enzymes in OGD/R-induced PC12 cells. In vivo, POH remarkably lessened infarct volume, reduced cerebral edema, accelerated tissue regeneration, and blocked reactive astrogliosis after hypoxic-ischemic brain injury. POH exerted antiapoptotic activities through both the intrinsic and extrinsic apoptotic pathways. Mechanistically, POH activated Nrf2 and inactivated its negative regulator Keap1. The use of ML385, a Nrf2 inhibitor, reversed these effects. Overall, POH mitigates neuronal damage in HIE by combating oxidative stress, reducing inflammation, and inhibiting apoptosis via the Nrf2/Keap1 pathway, suggesting its potential for HIE treatment.

Design, synthesis and biological evaluation of N-salicyloyl tryptamine derivatives as multifunctional neuroprotectants for the treatment of ischemic stroke

Ischemic stroke (IS) is a disease of high death and disability worldwide with few medications in clinical treatment. Neuroinflammation and oxidative stress are considered as crucial factors in the progression of IS. In our previous studies, N-salicyloyl tryptamine derivative (NST) L7 exhibited promising anti-inflammatory properties and is considered a potential clinical therapy for IS but had limited antioxidant capacity. Here, we have designed, synthesized, and biologically evaluated 30 novel NSTs for their neuroprotective effects against cerebral ischemia-reperfusion (CI/R) injury. To identify a multifunctional neuroprotectant with enhanced antioxidant and anti-inflammatory capacity, as well as an effective therapeutic agent for CI/R damage. Among them, M11 exhibited synergistic highly anti-oxidant, anti-inflammatory, anti-ferroptosis, and anti-apoptosis effects and surpassed the parent compound L7. Further studies demonstrated that the synergistic and efficient neuroprotective role of M11 was mainly achieved by activating Nrf2 and stimulating its downstream target HO-1/GCLC/NQO1/GPX4. In addition, M11 possessed good blood-brain barrier permeability. Moreover, M11 effectively reduced cerebral infarct volume and improved neurological deficits in MCAO/R mice. Its hydrochloride form, M11·HCl, exhibited better pharmacokinetic properties, high safety, and a significant reduction in infarct volume, which is comparable to Edaravone. In conclusion, our findings suggested that M11 capable of activating Nrf2, could represent a promising candidate agent for IS.

Neural Processing without O2 and Glucose Delivery: Lessons from the Pond to the Clinic

Neuronal activity requires a large amount of ATP, leading to a rapid collapse of brain function when aerobic respiration fails. Here, we summarize how rhythmic motor circuits in the brain stem of adult frogs, which normally have high metabolic demands, transform to produce proper output during severe hypoxia associated with emergence from hibernation. We suggest that general principles underlying plasticity in brain bioenergetics may be uncovered by studying nonmammalian models that face extreme environments, yielding new insights to combat neurological disorders involving dysfunctional energy metabolism.

Potential application of natural compounds in ischaemic stroke: Focusing on the mechanisms underlying "lysosomocentric" dysfunction of the autophagy-lysosomal pathway

Ischaemic stroke (IS) is the second leading cause of death and a major cause of disability worldwide. Currently, the clinical management of IS still depends on restoring blood flow via pharmacological thrombolysis or mechanical thrombectomy, with accompanying disadvantages of narrow therapeutic time window and risk of haemorrhagic transformation. Thus, novel pathophysiological mechanisms and targeted therapeutic candidates are urgently needed. The autophagy-lysosomal pathway (ALP), as a dynamic cellular lysosome-based degradative process, has been comprehensively studied in recent decades, including its upstream regulatory mechanisms and its role in mediating neuronal fate after IS. Importantly, increasing evidence has shown that IS can lead to lysosomal dysfunction, such as lysosomal membrane permeabilization, impaired lysosomal acidity, lysosomal storage disorder, and dysfunctional lysosomal ion homeostasis, which are involved in the IS-mediated defects in ALP function. There is tightly regulated crosstalk between transcription factor EB (TFEB), mammalian target of rapamycin (mTOR) and lysosomal function, but their relationship remains to be systematically summarized. Notably, a growing body of evidence emphasizes the benefits of naturally derived compounds in the treatment of IS via modulation of ALP function. However, little is known about the roles of natural compounds as modulators of lysosomes in the treatment of IS. Therefore, in this context, we provide an overview of the current understanding of the mechanisms underlying IS-mediated ALP dysfunction, from a lysosomal perspective. We also provide an update on the effect of natural compounds on IS, according to their chemical structural types, in different experimental stroke models, cerebral regions and cell types, with a primary focus on lysosomes and autophagy initiation. This review aims to highlight the therapeutic potential of natural compounds that target lysosomal and ALP function for IS treatment.

Dynamic Brain Lipid Profiles Modulate Microglial Lipid Droplet Accumulation and Inflammation Under Ischemic Conditions in Mice

Microglia are critically involved in post-stroke inflammation affecting neurological outcomes. Lipid droplet (LD) accumulation in microglia results in a dysfunctional and pro-inflammatory state in the aged brain and worsens the outcome of neuroinflammatory and neurodegenerative diseases. However, the role of LD-rich microglia (LDRM) under stroke conditions is unknown. Using in vitro and in vivo stroke models, herein accumulation patterns of microglial LD and their corresponding microglial inflammatory signaling cascades are studied. Interactions between temporal and spatial dynamics of lipid profiles and microglial phenotypes in different post-stroke brain regions are found. Hence, microglia display enhanced levels of LD accumulation and elevated perilipin 2 (PLIN2) expression patterns when exposed to hypoxia or stroke. Such LDRM exhibit high levels of TNF-α, IL-6, and IL-1β as well as a pro-inflammatory phenotype and differentially expressed lipid metabolism-related genes. These post-ischemic alterations result in distinct lipid profiles with spatial and temporal dynamics, especially with regard to cholesteryl ester and triacylglycerol levels, further exacerbating post-ischemic inflammation. The present study sheds new light on the dynamic changes of brain lipid profiles and aggregation patterns of LD in microglia exposed to ischemia, demonstrating a mutual mechanism between microglial phenotype and function, which contributes to progression of brain injury.

PFKFB3 ameliorates ischemia-induced neuronal damage by reducing reactive oxygen species and inhibiting nuclear translocation of Cdk5

The enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFKFB) plays an essential role in glycolysis and in the antioxidant pathway associated with glutathione. Therefore, we investigated the effects of PFKFB3 on oxidative and ischemic damage. We synthesized a fusion protein of transactivator of transcription (Tat)-PFKFB3 to facilitate its passage into the intracellular space and examine its effects against oxidative stress induced by hydrogen peroxide (H2O2) treatment and ischemic damage caused by occlusion of the common carotid arteries for 5 min in gerbils. The Tat-PFKFB3 protein was efficiently delivered into HT22 cells in a concentration- and time-dependent manner, with higher levels observed 18 h after treatment. Furthermore, treatment with 6 µM Tat-PFKFB3 demonstrated intracellular delivery into HT22 cells, as analyzed through immunocytochemical staining. Moreover, it significantly ameliorated the reduction of cell viability induced by 200 µM H2O2 treatment. Tat-PFKFB3 treatment also alleviated H2O2-induced DNA fragmentation and reactive oxygen species formation in HT22 cells. In gerbils, the intraperitoneal administration of 2 mg/kg Tat-PFKFB3 efficiently delivered the substance to all hippocampal areas, including the hippocampal CA1 region. This administration significantly mitigated ischemia-induced hyperlocomotion, long-term memory deficits, and ischemic neuronal death in the hippocampal CA1 region after ischemia. Additionally, treatment with 2 mg/kg Tat-PFKFB3 significantly ameliorated the translocation of Cdk5 from the cytosol to the nucleus in the hippocampal CA1 region 24 h after ischemia, but not in other regions. The treatment also significantly reduced reactive oxygen species formation in the CA1 region. These findings suggest that Tat-PFKFB3 reduces neuronal damage in the hippocampal CA1 region after ischemia through the reduction of Cdk5 signaling and reactive oxygen species formation. Therefore, Tat-PFKFB3 may have potential applications in reducing ischemic damage.

Soluble Epoxide Hydrolase Inhibitor Ameliorates Olfactory Dysfunction, Modulates Microglia Polarization, and Attenuates Neuroinflammation after Ischemic Brain Injury

Olfactory bulb (OB) microglia activation and inflammation can lead to olfactory dysfunction, which often occurs after an ischemic stroke. Inhibition of soluble epoxide hydrolase (sEH) attenuates neuroinflammation in brain injuries by reducing the degradation of anti-inflammatory epoxyeicosatrienoic acids. However, whether sEH inhibitors can ameliorate olfactory dysfunction after an ischemic stroke remains unknown. Ischemic brain injury and olfactory dysfunction were induced by middle cerebral artery occlusion (MCAO) in Wistar Kyoto rats. The rats were administered 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA), a selective sEH inhibitor. Olfactory function, cerebral infarct volume, and the degree of degeneration, microglial polarization and neuroinflammation in OB were evaluated. Following treatment with AUDA, rats subjected to MCAO displayed mild cerebral infarction and OB degeneration, as well as better olfactory performance. In OB, AUDA triggered a modulation of microglial polarization toward the M2 anti-inflammatory type, reduction in proinflammatory mediators, and enhancement of the antioxidant process. The effectiveness of AUDA in terms of anti-inflammatory, neuroprotection and anti-oxidative properties suggests that it may have clinical therapeutic implication for ischemic stroke related olfactory dysfunction.

Simulating Cerebral Edema and Ischemia After Traumatic Acute Subdural Hematoma Using Triphasic Swelling Biomechanics

Poor outcome following traumatic acute subdural hematoma (ASDH) is associated with the severity of the primary injury and secondary injury including cerebral edema and ischemia. However, the underlying secondary injury mechanism contributing to elevated intracranial pressure (ICP) and high mortality rate remains unclear. Cerebral edema occurs in response to the exposure of the intracellular fixed charge density (FCD) after cell death, causing ICP to increase. The increased ICP from swollen tissue compresses blood vessels in adjacent tissue, restricting blood flow and leading to ischemic damage. We hypothesize that the mass occupying effect of ASDH exacerbates the ischemic injury, leading to ICP elevation, which is an indicator of high mortality rate in the clinic. Using FEBio (febio.org) and triphasic swelling biomechanics, this study modeled clinically relevant ASDHs and simulated post-traumatic brain swelling and ischemia to predict ICP. Results showed that common convexity ASDH significantly increased ICP by exacerbating ischemic injury, and surgical removal of the convexity ASDH may control ICP by preventing ischemia progression. However, in cases where the primary injury is very severe, surgical intervention alone may not effectively decrease ICP, as the contribution of the hematoma to the elevated ICP is insignificant. In addition, interhemispheric ASDH, located between the cerebral hemispheres, does not significantly exacerbate ischemia, supporting the conservative surgical management generally recommended for interhemispheric ASDH. The joint effect of the mass occupying effect of the blood clot and resulting ischemia contributes to elevated ICP which may increase mortality. Our novel approach may improve the fidelity of predicting patient outcome after motor vehicle crashes and traumatic brain injuries due to other causes.

Current Trends in Stroke Biomarkers: The Prognostic Role of S100 Calcium-Binding Protein B and Glial Fibrillary Acidic Protein

Stroke is the third leading cause of death in the developed world and a major cause of chronic disability, especially among the elderly population. The major biomarkers of stroke which are the most promising for predicting onset time and independently differentiating ischemic from hemorrhagic and other stroke subtypes are at present limited to a few. This review aims to emphasize on the prognostic role of S100 calcium-binding protein b (S100B), and Glial Fibrillary Acidic Protein (GFAP) in patients with stroke. An electronic search of the published research from January 2000 to February 2024 was conducted using the MEDLINE, Scopus, and Cochrane databases. The implementation of S100B and GFAP in existing clinical scales and imaging modalities may be used to improve diagnostic accuracy and realize the potential of blood biomarkers in clinical practice. The reviewed studies highlight the potential of S100B and GFAP as significant biomarkers in the prognosis and diagnosis of patients with stroke and their ability of predicting long-term neurological deficits. They demonstrate high sensitivity and specificity in differentiating between ischemic and hemorrhagic stroke and they correlate well with stroke severity and outcomes. Several studies also emphasize on the early elevation of these biomarkers post-stroke onset, underscoring their value in early diagnosis and risk stratification. The ongoing research in this field should aim at improving patient outcomes and reducing stroke-related morbidity and mortality by developing a reliable, non-invasive diagnostic tool that can be easily implemented in several healthcare settings, with the ultimate goal of improving stroke management.

Interference with glutamate antiporter system xc - enables post-hypoxic long-term potentiation in hippocampus

Our group previously showed that genetic or pharmacological inhibition of the cystine/glutamate antiporter, system xc -, mitigates excitotoxicity after anoxia by increasing latency to anoxic depolarization, thus attenuating the ischaemic core. Hypoxia, however, which prevails in the ischaemic penumbra, is a condition where neurotransmission is altered, but excitotoxicity is not triggered. The present study employed mild hypoxia to further probe ischaemia-induced changes in neuronal responsiveness from wild-type and xCT KO (xCT-/-) mice. Synaptic transmission was monitored in hippocampal slices from both genotypes before, during and after a hypoxic episode. Although wild-type and xCT-/- slices showed equal suppression of synaptic transmission during hypoxia, mutant slices exhibited a persistent potentiation upon re-oxygenation, an effect we termed 'post-hypoxic long-term potentiation (LTP)'. Blocking synaptic suppression during hypoxia by antagonizing adenosine A1 receptors did not preclude post-hypoxic LTP. Further examination of the induction and expression mechanisms of this plasticity revealed that post-hypoxic LTP was driven by NMDA receptor activation, as well as increased calcium influx, with no change in paired-pulse facilitation. Hence, the observed phenomenon engaged similar mechanisms as classical LTP. This was a remarkable finding as theta-burst stimulation-induced LTP was equivalent between genotypes. Importantly, post-hypoxic LTP was generated in wild-type slices pretreated with system xc - inhibitor, S-4-carboxyphenylglycine, thereby confirming the antiporter's role in this phenomenon. Collectively, these data indicate that system xc - interference enables neuroplasticity in response to mild hypoxia, and, together with its regulation of cellular damage in the ischaemic core, suggest a role for the antiporter in post-ischaemic recovery of the penumbra.

The role of amino acid metabolism alterations in acute ischemic stroke: From mechanism to application

Acute ischemic stroke (AIS) is the most prevalent type of stroke, and due to its high incidence, disability rate, and mortality rate, it imposes a significant burden on the health care system. Amino acids constitute one of the most crucial metabolic products within the human body, and alterations in their metabolic pathways have been identified in the microenvironment of AIS, thereby influencing the pathogenesis, severity, and prognosis of AIS. The amino acid metabolism characteristics in AIS are complex. On one hand, the dynamic progression of AIS continuously reshapes the amino acid metabolism pattern. Conversely, changes in the amino acid metabolism pattern also exert a double-edged effect on AIS. This interaction is bidirectional, dynamic, heterogeneous, and dose-specific. Therefore, the distinctive metabolic reprogramming features surrounding amino acids during the AIS process are systematically summarized in this paper, aiming to provide potential investigative strategies for the early diagnosis, treatment approaches, and prognostic enhancement of AIS.

The role of ferroptosis as a regulator of oxidative stress in the pathogenesis of ischemic stroke

Ferroptosis is a unique form of cell death that was first described in 2012 and plays a significant role in various diseases, including neurodegenerative conditions. It depends on a dysregulation of cellular iron metabolism, which increases free, redox-active, iron that can trigger Fenton reactions, generating hydroxyl radicals that damage cells through oxidative stress and lipid peroxidation. Lipid peroxides, resulting mainly from unsaturated fatty acids, damage cells by disrupting membrane integrity and propagating cell death signals. Moreover, lipid peroxide degradation products can further affect cellular components such as DNA, proteins, and amines. In ischemic stroke, where blood flow to the brain is restricted, there is increased iron absorption, oxidative stress, and compromised blood-brain barrier integrity. Imbalances in iron-transport and -storage proteins increase lipid oxidation and contribute to neuronal damage, thus pointing to the possibility of brain cells, especially neurons, dying from ferroptosis. Here, we review the evidence showing a role of ferroptosis in ischemic stroke, both in recent studies directly assessing this type of cell death, as well as in previous studies showing evidence that can now be revisited with our new knowledge on ferroptosis mechanisms. We also review the efforts made to target ferroptosis in ischemic stroke as a possible treatment to mitigate cellular damage and death.

Development of a Predictive Nomogram for Intra-Hospital Mortality in Acute Ischemic Stroke Patients Using LASSO Regression

Background and Purpose

Ischemic stroke is a leading cause of mortality and disability globally, necessitating accurate prediction of intra-hospital mortality (IHM) for improved patient care. This study aimed to develop a practical nomogram for personalized IHM risk prediction in ischemic stroke patients.

Methods

A retrospective study of 422 ischemic stroke patients (April 2020 - December 2021) from Chongqing Medical University's First Affiliated Hospital was conducted, with patients divided into training (n=295) and validation (n=127) groups. Data on demographics, comorbidities, stroke risk factors, and lab results were collected. Stroke severity was assessed using NIHSS, and stroke types were classified by TOAST criteria. Least absolute shrinkage and selection operator (LASSO) regression was employed for predictor selection and nomogram construction, with evaluation through ROC curves, calibration curves, and decision curve analysis.

Results

LASSO regression and multivariate logistic regression identified four independent IHM predictors: age, admission NIHSS score, chronic obstructive pulmonary disease (COPD) diagnosis, and white blood cell count (WBC). A highly accurate nomogram based on these variables exhibited excellent predictive performance, with AUCs of 0.958 (training) and 0.962 (validation), sensitivities of 93.2% and 95.7%, and specificities of 93.1% and 90.9%, respectively. Calibration curves and decision curve analysis validated its clinical applicability.

Conclusion

Age, admission NIHSS score, COPD history, and WBC were identified as independent IHM predictors in ischemic stroke patients. The developed nomogram demonstrated high predictive accuracy and practical utility for mortality risk estimation. External validation and prospective studies are warranted for further confirmation of its clinical efficacy.

Region-specific protective effects of monomethyl fumarate in cerebellar and hippocampal organotypic slice cultures following oxygen-glucose deprivation

To date, apart from moderate hypothermia, there are almost no adequate interventions available for neuroprotection in cases of brain damage due to cardiac arrest. Affected persons often have severe limitations in their quality of life. The aim of this study was to investigate protective properties of the active compound of dimethyl fumarate, monomethyl fumarate (MMF), on distinct regions of the central nervous system after ischemic events. Dimethyl fumarate is an already established drug in neurology with known anti-inflammatory and antioxidant properties. In this study, we chose organotypic slice cultures of rat cerebellum and hippocampus as an ex vivo model. To simulate cardiac arrest and return of spontaneous circulation we performed oxygen-glucose-deprivation (OGD) followed by treatments with different concentrations of MMF (1-30 μM in cerebellum and 5-30 μM in hippocampus). Immunofluorescence staining with propidium iodide (PI) and 4',6-diamidine-2-phenylindole (DAPI) was performed to analyze PI/DAPI ratio after imaging with a spinning disc confocal microscope. In the statistical analysis, the relative cell death of the different groups was compared. In both, the cerebellum and hippocampus, the MMF-treated group showed a significantly lower PI/DAPI ratio compared to the non-treated group after OGD. Thus, we showed for the first time that both cerebellar and hippocampal slice cultures treated with MMF after OGD are significantly less affected by cell death.

Association of serum uric acid to serum creatinine ratio with 1-year stroke outcomes in patients with acute ischemic stroke: A multicenter observational cohort study

BACKGROUND AND PURPOSE

Considering the reliance of serum uric acid (SUA) levels on renal clearance function, its role in stroke outcomes remains controversial. This study investigated the association of renal function-normalized SUA (SUA to serum creatinine ratio, SUA/SCr), a novel renal function index, with the 1-year outcomes in patients with acute ischemic stroke (AIS).

METHODS

This is a prospective, multicenter observational study. Renal function-normalized SUA levels were determined by calculating the ratio of SUA to SCr. One-year outcomes included stroke recurrence, all-cause mortality, and poor prognosis. Multivariable Cox regression analyses and restriction cubic splines for curve fitting were used to evaluate SUA/SCr's association with 1-year stroke outcomes.

RESULTS

Among 2294 enrolled patients, after adjustment for potential confounders, multivariable Cox regression analyses showed that each one-unit increase in SUA/SCr corresponded to a 19% decrease in 1-year stroke recurrence in patients with AIS. SUA/SCr was analyzed as a continuous variable and categorized into quartiles (Q1-Q4). Compared with the Q1 reference group, Q2, Q3, and Q4 showed significantly lower 1-year stroke recurrence risks. The trend test indicated significant differences in the 1-year stroke recurrence trend from Q1 to Q4. In these patients, SUA/SCr did not show a significant association with poor prognosis or all-cause mortality. Curve fitting revealed SUA/SCr had a negative but nonlinear association with 1-year stroke recurrence.

CONCLUSIONS

In patients with AIS, low SUA/SCr may be an independent risk factor for 1-year stroke recurrence. Changes in SUA/SCr had no significant impact on 1-year poor prognosis and all-cause mortality.

Quantitative analysis of systemic perfusion and cerebral blood flow in the modeling of aging and orthostatic hypotension

Introduction: Orthostatic hypotension (OH) is common among the older population. The mechanism hypothesized by OH as a risk factor for cognitive decline and dementia is repeated transient cerebral blood flow deficiency. However, to our knowledge, quantitative evaluation of cardiac output and cerebral blood flow due to acute blood pressure changes resulting from postural changes is rare. Methods: We report a new fluid-structure interaction model to analyze the quantitative relationship of cerebral blood flow during OH episodes. A device was designed to simulate the aging of blood vessels. Results and Discussion: The results showed that OH was associated with decreased transient cerebral blood flow. With the arterial aging, lesions, the reduction in cerebral blood flow is accelerated. These findings suggest that systolic blood pressure regulation is more strongly associated with cerebral blood flow than diastolic blood pressure, and that more severe OH carries a greater risk of dementia. The model containing multiple risk factors could apply to analyze and predict for individual patients. This study could explain the hypothesis that transient cerebral blood flow deficiency in recurrent OH is associated with cognitive decline and dementia.

A comprehensive review on the neuroprotective potential of resveratrol in ischemic stroke

Stroke is the second leading cause of death and the third leading cause of disability worldwide. Globally, 68 % of all strokes are ischemic, with 32 % being hemorrhagic. Ischemic stroke (IS) poses significant challenges globally, necessitating the development of effective therapeutic strategies. IS is among the deadliest illnesses. Major functions are played by neuroimmunity, inflammation, and oxidative stress in the multiple intricate pathways of IS. Secondary brain damage is specifically caused by the early pro-inflammatory activity that follows cerebral ischemia, which is brought on by excessive activation of local microglia and the infiltration of circulating monocytes and macrophages. Resveratrol, a natural polyphenol found in grapes and berries, has shown promise as a neuroprotective agent in IS. This review offers a comprehensive overview of resveratrol's neuroprotective role in IS, focusing on its mechanisms of action and therapeutic potential. Resveratrol exerts neuroprotective effects by activating nuclear factor erythroid 2-related factor 2 (NRF2) and sirtuin 1 (SIRT1) pathways. SIRT1 activation by resveratrol triggers the deacetylation and activation of downstream targets like peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α) and forkhead box protein O (FOXO), regulating mitochondrial biogenesis, antioxidant defense, and cellular stress response. Consequently, resveratrol promotes cellular survival and inhibits apoptosis in IS. Moreover, resveratrol activates the NRF2 pathway, a key mediator of the cellular antioxidant response. Activation of NRF2 through resveratrol enhances the expression of antioxidant enzymes, like heme oxygenase-1 (HO-1) and NAD(P)H quinone oxidoreductase 1 (NQO1), which neutralize reactive oxygen species and mitigate oxidative stress in the ischemic brain. Combined, the activation of SIRT1 and NRF2 pathways contributes to resveratrol's neuroprotective effects by reducing oxidative stress, inflammation, and apoptosis in IS. Preclinical studies demonstrate that resveratrol improves functional outcomes, reduces infarct size, regulates cerebral blood flow and preserves neuronal integrity. Gaining a comprehensive understanding of these mechanisms holds promise for the development of targeted therapeutic interventions aimed at promoting neuronal survival and facilitating functional recovery in IS patients and to aid future studies in this matter.

Influence of Cooling duration on Efficacy in Cardiac Arrest Patients (ICECAP): study protocol for a multicenter, randomized, adaptive allocation clinical trial to identify the optimal duration of induced hypothermia for neuroprotection in comatose, adult survivors of after out-of-hospital cardiac arrest

BACKGROUND

Cardiac arrest is a common and devastating emergency of both the heart and brain. More than 380,000 patients suffer out-of-hospital cardiac arrest annually in the USA. Induced cooling of comatose patients markedly improved neurological and functional outcomes in pivotal randomized clinical trials, but the optimal duration of therapeutic hypothermia has not yet been established.

METHODS

This study is a multi-center randomized, response-adaptive, duration (dose) finding, comparative effectiveness clinical trial with blinded outcome assessment. We investigate two populations of adult comatose survivors of cardiac arrest to ascertain the shortest duration of cooling that provides the maximum treatment effect. The design is based on a statistical model of response as defined by the primary endpoint, a weighted 90-day mRS (modified Rankin Scale, a measure of neurologic disability), across the treatment arms. Subjects will initially be equally randomized between 12, 24, and 48 h of therapeutic cooling. After the first 200 subjects have been randomized, additional treatment arms between 12 and 48 h will be opened and patients will be allocated, within each initial cardiac rhythm type (shockable or non-shockable), by response adaptive randomization. As the trial continues, shorter and longer duration arms may be opened. A maximum sample size of 1800 subjects is proposed. Secondary objectives are to characterize: the overall safety and adverse events associated with duration of cooling, the effect on neuropsychological outcomes, and the effect on patient-reported quality of life measures.

DISCUSSION

In vitro and in vivo studies have shown the neuroprotective effects of therapeutic hypothermia for cardiac arrest. We hypothesize that longer durations of cooling may improve either the proportion of patients that attain a good neurological recovery or may result in better recovery among the proportion already categorized as having a good outcome. If the treatment effect of cooling is increasing across duration, for at least some set of durations, then this provides evidence of the efficacy of cooling itself versus normothermia, even in the absence of a normothermia control arm, confirming previous RCTs for OHCA survivors of shockable rhythms and provides the first prospective controlled evidence of efficacy in those without initial shockable rhythms.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04217551. Registered on 30 December 2019.

Neuroprotective Effects of Inhaled Xenon Gas on Brain Structural Gray Matter Changes After Out-of-Hospital Cardiac Arrest Evaluated by Morphometric Analysis: A Substudy of the Randomized Xe-Hypotheca Trial

BACKGROUND

We have earlier reported that inhaled xenon combined with hypothermia attenuates brain white matter injury in comatose survivors of out-of-hospital cardiac arrest (OHCA). A predefined secondary objective was to assess the effect of inhaled xenon on the structural changes in gray matter in comatose survivors after OHCA.

METHODS

Patients were randomly assigned to receive either inhaled xenon combined with target temperature management (33 °C) for 24 h (n = 55, xenon group) or target temperature management alone (n = 55, control group). A change of brain gray matter volume was assessed with a voxel-based morphometry evaluation of high-resolution structural brain magnetic resonance imaging (MRI) data with Statistical Parametric Mapping. Patients were scheduled to undergo the first MRI between 36 and 52 h and a second MRI 10 days after OHCA.

RESULTS

Of the 110 randomly assigned patients in the Xe-Hypotheca trial, 66 patients completed both MRI scans. After all imaging-based exclusions, 21 patients in the control group and 24 patients in the xenon group had both scan 1 and scan 2 available for analyses with scans that fulfilled the quality criteria. Compared with the xenon group, the control group had a significant decrease in brain gray matter volume in several clusters in the second scan compared with the first. In a between-group analysis, significant reductions were found in the right amygdala/entorhinal cortex (p = 0.025), left amygdala (p = 0.043), left middle temporal gyrus (p = 0.042), left inferior temporal gyrus (p = 0.008), left parahippocampal gyrus (p = 0.042), left temporal pole (p = 0.042), and left cerebellar cortex (p = 0.005). In the remaining gray matter areas, there were no significant changes between the groups.

CONCLUSIONS

In comatose survivors of OHCA, inhaled xenon combined with targeted temperature management preserved gray matter better than hypothermia alone.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT00879892.

Cerebral blood flow and end-tidal CO2 predict lightheadedness during head-up tilt in patients with orthostatic intolerance

Orthostatic intolerance (OI) is a common problem. Reliable markers of OI are missing, as orthostatic blood pressure and heart rate poorly correlate with orthostatic symptoms. The objective of this study was to assess the relationship between orthostatic lightheadedness and cerebral blood flow. In this retrospective study patients with OI were evaluated at the Autonomic Laboratory of the Department of Neurology, Brigham and Women's Faulkner Hospital, Boston. The 10-minute head-up tilt test was performed as a part of autonomic testing. Orthostatic lightheadedness was evaluated at every minute of the head-up tilt. Heart rate, blood pressure, capnography, and cerebral blood flow velocity (CBFv) in the middle cerebral artery using transcranial Doppler were measured. Repeated-measures design with a linear mixed-effects model was used to evaluate the relationship between orthostatic lightheadedness and hemodynamic variables. Correlation analyses were done by calculating Pearson's coefficient. Twenty-two patients with OI were compared to nineteen controls. Orthostatic CBFv and end-tidal CO2 decreased in OI patients compared to controls (p < 0.001) and predicted orthostatic lightheadedness. Orthostatic heart rate and blood pressure failed to predict orthostatic lightheadedness. The lightheadedness threshold, which marked the onset of lightheadedness, was equal to an average systolic CBFv decrease of 18.92% and end-tidal CO2 of 12.82%. The intensity of lightheadedness was proportional to the CBFv and end-tidal CO2 decline. Orthostatic lightheadedness correlated with systolic CBFv (r=-0.6, p < 0.001) and end-tidal CO2 (r=-0.33, p < 0.001) decline. In conclusion, orthostatic CBFv and end-tidal CO2 changes predict orthostatic lightheadedness and can be used as objective markers of OI.

The neuroprotective effects of normobaric oxygen therapy after stroke

BACKGROUND

Stroke, including ischemic and hemorrhagic stroke, is a severe and prevalent acute cerebrovascular disease. The development of hypoxia following stroke can trigger a cascade of pathological events, including mitochondrial dysfunction, energy deficiency, oxidative stress, neuroinflammation, and excitotoxicity, all of which are often associated with unfavorable prognosis. Nonetheless, a noninvasive intervention, referred to as normobaric hyperoxia (NBO), is known to have neuroprotective effects against stroke.

RESULTS

NBO can exert neuroprotective effects through various mechanisms, such as the rescue of hypoxic tissues, preservation of the blood-brain barrier, reduction of brain edema, alleviation of neuroinflammation, improvement of mitochondrial function, mitigation of oxidative stress, reduction of excitotoxicity, and inhibition of apoptosis. These mechanisms may help improve the prognosis of stroke patients.

CONCLUSIONS

This review summarizes the mechanism by which hypoxia causes brain injury and how NBO can act as a neuroprotective therapy to treat stroke. We conclude that NBO has significant potential for treating stroke and may represent a novel therapeutic strategy.

Bidirectional regulation mechanism of TRPM2 channel: role in oxidative stress, inflammation and ischemia-reperfusion injury

Transient receptor potential melastatin 2 (TRPM2) is a non-selective cation channel that exhibits Ca2+ permeability. The TRPM2 channel is expressed in various tissues and cells and can be activated by multiple factors, including endogenous ligands, Ca2+, reactive oxygen species (ROS) and temperature. This article reviews the multiple roles of the TRPM2 channel in physiological and pathological processes, particularly on oxidative stress, inflammation and ischemia-reperfusion (I/R) injury. In oxidative stress, the excessive influx of Ca2+ caused by the activation of the TRPM2 channel may exacerbate cellular damage. However, under specific conditions, activating the TRPM2 channel can have a protective effect on cells. In inflammation, the activation of the TRPM2 channel may not only promote inflammatory response but also inhibit inflammation by regulating ROS production and bactericidal ability of macrophages and neutrophils. In I/R, the activation of the TRPM2 channel may worsen I/R injury to various organs, including the brain, heart, kidney and liver. However, activating the TRPM2 channel may protect the myocardium from I/R injury by regulating calcium influx and phosphorylating proline-rich tyrosine kinase 2 (Pyk2). A thorough investigation of the bidirectional role and regulatory mechanism of the TRPM2 channel in these physiological and pathological processes will aid in identifying new targets and strategies for treatment of related diseases.

Deregulation of oxidative phosphorylation pathways in embryos derived in vitro from prepubertal and pubertal heifers based on whole-transcriptome sequencing

BACKGROUND

Although, oocytes from prepubertal donors are known to be less developmentally competent than those from adult donors it does not restrain their ability to produce full-term pregnancies. The transcriptomic profile of embryos could be used as a predictor for embryo's individual developmental competence. The aim of the study was to compare transcriptomic profile of blastocysts derived from prepubertal and pubertal heifers oocytes. Bovine cumulus-oocyte complexes (COCs) were obtained by ovum pick- up method from prepubertal and pubertal heifers. After in vitro maturation COCs were fertilized and cultured to the blastocyst stage. Total RNA was isolated from both groups of blastocysts and RNA-seq was performed. Gene ontology analysis was performed by DAVID (Database for Annotation, Visualization and Integrated Discovery).

RESULTS

A higher average blastocyst rate was obtained in the pubertal than in the pre-pubertal group. There were no differences in the quality of blastocysts between the examined groups. We identified 436 differentially expressed genes (DEGs) between blastocysts derived from researched groups, of which 247 DEGs were downregulated in blastocysts derived from pubertal compared to prepubertal heifers oocytes, and 189 DEGs were upregulated. The genes involved in mitochondrial function, including oxidative phosphorylation (OXPHOS) were found to be different in studied groups using Kyoto Encyclopedia of Genes (KEGG) pathway analysis and 8 of those DEGs were upregulated and 1 was downregulated in blastocysts derived from pubertal compared to prepubertal heifers oocytes. DEGs associated with mitochondrial function were found: ATP synthases (ATP5MF-ATP synthase membrane subunit f, ATP5PD- ATP synthase peripheral stalk subunit d, ATP12A- ATPase H+/K + transporting non-gastric alpha2 subunit), NADH dehydrogenases (NDUFS3- NADH: ubiquinone oxidoreductase subunit core subunit S3, NDUFA13- NADH: ubiquinone oxidoreductase subunit A13, NDUFA3- NADH: ubiquinone oxidoreductase subunit A3), cytochrome c oxidase (COX17), cytochrome c somatic (CYCS) and ubiquinol cytochrome c reductase core protein 1 (UQCRC1). We found lower number of apoptotic cells in blastocysts derived from oocytes collected from prepubertal than those obtained from pubertal donors.

CONCLUSIONS

Despite decreased expression of genes associated with OXPHOS pathway in blastocysts from prepubertal heifers oocytes, the increased level of ATP12A together with the lower number of apoptotic cells in these blastocysts might support their survival after transfer.

Influence of Cooling duration on Efficacy in Cardiac Arrest Patients (ICECAP): study protocol for a multicenter, randomized, adaptive allocation clinical trial to identify the optimal duration of induced hypothermia for neuroprotection in comatose, adult survivors of after out-of-hospital cardiac arrest

Background

Cardiac arrest is a common and devastating emergency of both the heart and brain. More than 380,000 patients suffer out-of-hospital cardiac arrest annually in the United States. Induced cooling of comatose patients markedly improved neurological and functional outcomes in pivotal randomized clinical trials, but the optimal duration of therapeutic hypothermia has not yet been established.

Methods

This study is a multi-center randomized, response-adaptive, duration (dose) finding, comparative effectiveness clinical trial with blinded outcome assessment. We investigate two populations of adult comatose survivors of cardiac arrest to ascertain the shortest duration of cooling that provides the maximum treatment effect. The design is based on a statistical model of response as defined by the primary endpoint, a weighted 90-day mRS (modified Rankin Scale, a measure of neurologic disability), across the treatment arms. Subjects will initially be equally randomized between 12, 24, and 48 hours of therapeutic cooling. After the first 200 subjects have been randomized, additional treatment arms between 12 and 48 hours will be opened and patients will be allocated, within each initial cardiac rhythm type (shockable or non-shockable), by response adaptive randomization. As the trial continues, shorter and longer duration arms may be opened. A maximum sample size of 1800 subjects is proposed. Secondary objectives are to characterize: the overall safety and adverse events associated with duration of cooling, the effect on neuropsychological outcomes, and the effect on patient reported quality of life measures.

Discussion

In-vitro and in-vivo studies have shown the neuroprotective effects of therapeutic hypothermia for cardiac arrest. We hypothesize that longer durations of cooling may improve either the proportion of patients that attain a good neurological recovery or may result in better recovery among the proportion already categorized as having a good outcome. If the treatment effect of cooling is increasing across duration, for at least some set of durations, then this provides evidence of the efficacy of cooling itself versus normothermia, even in the absence of a normothermia control arm, confirming previous RCTs for OHCA survivors of shockable rhythms and provides the first prospective controlled evidence of efficacy in those without initial shockable rhythms.

Trial registration

ClinicalTrials.gov (NCT04217551, 2019-12-30).

Alterations in brain fluid physiology during the early stages of development of ischaemic oedema

Oedema occurs when higher than normal amounts of solutes and water accumulate in tissues. In brain parenchymal tissue, vasogenic oedema arises from changes in blood-brain barrier permeability, e.g. in peritumoral oedema. Cytotoxic oedema arises from excess accumulation of solutes within cells, e.g. ischaemic oedema following stroke. This type of oedema is initiated when blood flow in the affected core region falls sufficiently to deprive brain cells of the ATP needed to maintain ion gradients. As a consequence, there is: depolarization of neurons; neural uptake of Na+ and Cl- and loss of K+; neuronal swelling; astrocytic uptake of Na+, K+ and anions; swelling of astrocytes; and reduction in ISF volume by fluid uptake into neurons and astrocytes. There is increased parenchymal solute content due to metabolic osmolyte production and solute influx from CSF and blood. The greatly increased [K+]isf triggers spreading depolarizations into the surrounding penumbra increasing metabolic load leading to increased size of the ischaemic core. Water enters the parenchyma primarily from blood, some passing into astrocyte endfeet via AQP4. In the medium term, e.g. after three hours, NaCl permeability and swelling rate increase with partial opening of tight junctions between blood-brain barrier endothelial cells and opening of SUR1-TPRM4 channels. Swelling is then driven by a Donnan-like effect. Longer term, there is gross failure of the blood-brain barrier. Oedema resolution is slower than its formation. Fluids without colloid, e.g. infused mock CSF, can be reabsorbed across the blood-brain barrier by a Starling-like mechanism whereas infused serum with its colloids must be removed by even slower extravascular means. Large scale oedema can increase intracranial pressure (ICP) sufficiently to cause fatal brain herniation. The potentially lethal increase in ICP can be avoided by craniectomy or by aspiration of the osmotically active infarcted region. However, the only satisfactory treatment resulting in retention of function is restoration of blood flow, providing this can be achieved relatively quickly. One important objective of current research is to find treatments that increase the time during which reperfusion is successful. Questions still to be resolved are discussed.

Remote Ischemic Postconditioning-Mediated Neuroprotection against Stroke by Promoting Ketone Body-Induced Ferroptosis Inhibition

Neuronal death resulting from ischemic stroke is the primary cause of adult mortality and disability, and effective neuroprotective agents for poststroke intervention are still lacking. Remote ischemic postconditioning (RIPostC) has demonstrated significant protective effects against ischemia in various organs; however, the specific mechanisms are not fully understood. This study investigated the potential neuroprotective mechanisms of RIPostC in the context of ischemic stroke. Using a rat model of middle cerebral artery occlusion, we found that RIPostC mitigated neurological damage, improved movement in the open-field test, and protected against neuronal apoptosis. In terms of energy metabolism, RIPostC enhanced ATP levels, suppressed lactate content, and increased the production of ketone bodies (KBs). In the ferroptosis assay, RIPostC protected against lipoperoxidation, reversed the reduction of glutathione peroxidase 4 (GPX4), and mitigated the excessive expression of long-chain acyl-CoA synthetase family member 4 (ACSL4). In oxygen-glucose deprivation/reoxygenation-treated HT22 cells, KBs maintained GPX4 levels, suppressed ACSL4 expression, and preserved the mitochondrial cristae number. However, the effect of KBs on the expression of GPX4, ACSL4, and the number of mitochondrial cristae was blocked by erastin. Moreover, both RIPostC and KBs reduced total iron and ferrous ion content by repressing iron transporters both in vitro and in vivo. In conclusion, KBs-induced mitigation of ferroptosis could represent a new therapeutic mechanism for RIPostC in treating stroke.

Peroxynitrite-Triggered Carbon Monoxide Donor Improves Ischemic Stroke Outcome by Inhibiting Neuronal Apoptosis and Ferroptosis

Cerebral ischemia-reperfusion injury produces excessive reactive oxygen and nitrogen species, including superoxide, nitric oxide, and peroxynitrite (ONOO-). We recently developed a new ONOO--triggered metal-free carbon monoxide donor (PCOD585), exhibiting a notable neuroprotective outcome on the rat middle cerebral artery occlusion model and rendering an exciting intervention opportunity toward ischemia-induced brain injuries. However, its therapeutic mechanism still needs to be addressed. In the pharmacological study, we found PCOD585 inhibited neuronal Bcl2/Bax/caspase-3 apoptosis pathway in the peri-infarcted area of stroke by scavenging ONOO-. ONOO- scavenging further led to decreased Acyl-CoA synthetase long-chain family member 4 and increased glutathione peroxidase 4, to minimize lipoperoxidation. Additionally, the carbon monoxide release upon the ONOO- reaction with PCOD585 further inhibited the neuronal Iron-dependent ferroptosis associated with ischemia-reperfusion. Such a synergistic neuroprotective mechanism of PCOD585 yields as potent a neuroprotective effect as Edaravone. Additionally, PCOD585 penetrates the blood-brain barrier and reduces the degradation of zonula occludens-1 by inhibiting matrix metalloproteinase-9, thereby protecting the integrity of the blood-brain barrier. Our study provides a new perspective for developing multi-functional compounds to treat ischemic stroke.

FGF17 protects cerebral ischemia reperfusion-induced blood-brain barrier disruption via FGF receptor 3-mediated PI3K/AKT signaling pathway

Maintaining blood-brain barrier (BBB) integrity is critical components of therapeutic approach for ischemic stroke. Fibroblast growth factor 17 (FGF17), a member of FGF8 superfamily, exhibits the strongest expression throughout the wall of all major arteries during development. However, its molecular action and potential protective role on brain endothelial cells after stroke remains unclear. Here, we observed reduced levels of FGF17 in the serum of patients with ischemic stroke, as well as in the brains of mice subjected to middle cerebral artery occlusion (MCAO) injury and oxygen-glucose deprivation/reoxygenation (OGD/R)-induced brain microvascular endothelial cells (bEnd.3) cells. Moreover, treatment with exogenous recombinant human FGF17 (rhFGF17) decreased infarct volume, improved neurological deficits, reduced Evans Blue leakage and upregulated the expression of tight junctions in MCAO-injured mice. Meanwhile, rhFGF17 increased cell viability, enhanced trans-endothelial electrical resistance, reduced sodium fluorescein leakage, and alleviated reactive oxygen species (ROS) generation in OGD/R-induced bEnd.3 cells. Mechanistically, the treatment with rhFGF17 resulted in nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear accumulation and upregulation of heme oxygenase-1 (HO-1) expression. Additionally, based on in-vivo and in-vitro research, rhFGF17 exerted protective effects against ischemia/reperfusion (I/R) -induced BBB disruption and endothelial cell apoptosis through the activation of the FGF receptor 3/PI3K/AKT signaling pathway. Overall, our findings indicated that FGF17 may hold promise as a novel therapeutic strategy for ischemic stroke patients.

Pannexin1 Channel-Mediated Inflammation in Acute Ischemic Stroke

Emerging evidence suggests that inflammation mediated by the pannexin1 channel contributes significantly to acute ischemic stroke. It is believed that the pannexin1 channel is key in initiating central system inflammation during the early stages of acute ischemic stroke. Moreover, the pannexin1 channel is involved in the inflammatory cascade to maintain the inflammation levels. Specifically, the interaction of pannexin1 channels with ATP-sensitive P2X7 purinoceptors or promotion of potassium efflux mediates the activation of the NLRP3 inflammasome, triggering the release of pro-inflammatory factors such as IL-1 and IL-18, exacerbating and sustaining inflammation of brain. Also, increased release of ATP induced by cerebrovascular injury activates pannexin1 in vascular endothelial cells. This signal directs peripheral leukocytes to migrate into ischemic brain tissue, leading to an expansion of the inflammatory zone. Intervention strategies targeting pannexin1 channels may greatly alleviate inflammation after acute ischemic stroke to improve this patient population's clinical outcomes. In this review, we sought to summarize relevant studies on inflammation mediated by the pannexin1 channel in acute ischemic stroke and discussed the possibility of using brain organoid-on-a-chip technology to screen miRNAs that exclusively target the pannexin1 channel to provide new therapeutic measures for targeted regulation of pannexin1 channel to reduce inflammation in acute ischemic stroke.

The effect of calpain inhibitor-I on copper oxide nanoparticle-induced damage and cerebral ischemia-reperfusion in a rat model

This study aimed to investigate the effects of the calpain inhibitor N-Acetyl-Leu-Leu-norleucinal (ALLN) on neuroapoptotic cell damage caused by Copper Oxide Nanoparticles (CuO-NP) and exacerbation of damage through brain ischemia/reperfusion (I/R) in a rat model. Male Wistar Albino rats (n=80) were divided into eight groups: Control, I/R, CuO-NP, CuO-NP+I/R, I/R+ALLN, CuO-NP+ALLN, CuO-NP+I/R+ALLN, and DMSO. Biochemical markers (MBP, S100B, NEFL, NSE, BCL-2, Cyt-C, Calpain, TNF-α, Caspase-3, MDA, and CAT) were measured in serum and brain tissue samples. Histological examinations (H&E staining), DNA fragmentation analysis (TUNEL) were performed, along with Caspase-3 assessment. The ALLN-treated groups exhibited significant improvements in biochemical markers and a remarkable reduction in apoptosis compared to the damaged groups (CuO-NP and I/R). H&E and Caspase-3 staining revealed damage-related morphological changes and reduced apoptosis in the ALLN-treated group. However, no differences were observed among the groups with TUNEL staining. The findings suggest that ALLN, as a calpain inhibitor, has potential implications for anti-apoptotic treatment, specifically in mitigating neuroapoptotic cell damage caused by CuO-NP and I/R.

An Update on Stiripentol Mechanisms of Action: A Narrative Review

Stiripentol (Diacomit®) (STP) is an orally active antiseizure medication (ASM) indicated as adjunctive therapy, for the treatment of seizures associated with Dravet syndrome (DS), a severe form of childhood epilepsy, in conjunction with clobazam and, in some regions valproic acid. Since the discovery of STP, several mechanisms of action (MoA) have been described that may explain its specific effect on seizures associated with DS. STP is mainly considered as a potentiator of gamma-aminobutyric acid (GABA) neurotransmission: (i) via uptake blockade, (ii) inhibition of degradation, but also (iii) as a positive allosteric modulator of GABAA receptors, especially those containing α3 and δ subunits. Blockade of voltage-gated sodium and T-type calcium channels, which is classically associated with anticonvulsant and neuroprotective properties, has also been demonstrated for STP. Finally, several studies indicate that STP could regulate glucose energy metabolism and inhibit lactate dehydrogenase. STP is also an inhibitor of several cytochrome P450 enzymes involved in the metabolism of other ASMs, contributing to boost their anticonvulsant efficacy as add-on therapy. These different MoAs involved in treatment of DS and recent data suggest a potential for STP to treat other neurological or non-neurological diseases.

Tanshinone IIA Alleviates Traumatic Brain Injury by Reducing Ischemia‒Reperfusion via the miR-124-5p/FoxO1 Axis

Background

Cerebral ischemia-reperfusion injury is a common complication of ischemic stroke that affects the prognosis of patients with ischemic stroke. The lipid-soluble diterpene Tanshinone IIA, which was isolated from Salvia miltiorrhiza, has been indicated to reduce cerebral ischemic injury. In this study, we investigated the molecular mechanism of Tanshinone IIA in alleviating reperfusion-induced brain injury.

Methods

Middle cerebral artery occlusion animal models were established, and neurological scores, tetrazolium chloride staining, brain volume quantification, wet and dry brain water content measurement, Nissl staining, enzyme-linked immunosorbent assay, flow cytometry, western blotting, and reverse transcription-quantitative polymerase chain reaction were performed. The viability of cells was measured by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide assays, while cell damage was measured by lactate dehydrogenase release in the in vitro oxygen glucose deprivation model. In addition, enzyme-linked immunosorbent assay, flow cytometry, western blotting, and reverse transcription-quantitative polymerase chain reaction were used to evaluate the therapeutic effect of Tanshinone IIA on ischemia/reperfusion (I/R) induced brain injury, as well as its effects on the inflammatory response and neuronal apoptosis, in vivo and in vitro. Furthermore, this study validated the targeting relationship between miR-124-5p and FoxO1 using a dual luciferase assay. Finally, we examined the role of Tanshinone IIA in brain injury from a molecular perspective by inhibiting miR-124-5p or increasing FoxO1 levels.

Results

After treatment with Tanshinone IIA in middle cerebral artery occlusion-reperfusion (MCAO/R) rats, the volume of cerebral infarction was reduced, the water content of the brain was decreased, the nerve function of the rats was significantly improved, and the cell damage was significantly reduced. In addition, Tanshinone IIA effectively inhibited the I/R-induced inflammatory response and neuronal apoptosis, that is, it inhibited the expression of inflammatory cytokines IL-1β, IL-6, TNF-α, decreased the expression of apoptotic protein Bax and Cleaved-caspase-3, and promoted the expression of antiapoptotic protein Bcl-2. In vitro oxygen-glucose deprivation/reoxygenation (OGD/R) cell model, Tanshinone IIA also inhibited the expression of inflammatory factors in neuronal cells and inhibited the occurrence of neuronal apoptosis. In addition, Tanshinone IIA promoted the expression of miR-124-5p. Transfection of miR-124-5p mimic has the same therapeutic effect as Tanshinone IIA and positive therapeutic effect on OGD cells, while transfection of miR-124-5p inhibitor has the opposite effect. The targeting of miR-124-5p negatively regulates FoxO1 expression. Inhibition of miR-124-5p or overexpression of FoxO1 can weaken the inhibitory effect of Tanshinone IIA on brain injury induced by I/R, while inhibition of miR-124-5p and overexpression of FoxO1 can further weaken the effect of Tanshinone IIA.

Conclusion

Tanshinone IIA alleviates ischemic-reperfusion brain injury by inhibiting neuroinflammation through the miR-124-5p/FoxO1 axis. This finding provides a theoretical basis for mechanistic research on cerebral ischemia-reperfusion injury.

Understanding the mechanism of acupuncture in acute cerebral infraction through a proteomic analysis: protocol for a prospective randomized controlled trial

Background

Acute cerebral infarction (ACI), being the predominant form of stroke, presents challenges in terms of the limited effectiveness of various treatments in improving the neurological function. Although acupuncture shows promise in addressing ACI, the availability of high-quality evidence regarding its efficacy, safety, and underlying mechanism remains insufficient. In this study, we design a multicenter, prospective, single-blind, randomized controlled trial with the aim of evaluating the efficacy and safety of acupuncture for ACI, making an attempt to unveil the molecular mechanisms by proteomic.

Methods

A total of 132 patients involving four hospitals will be randomized at a 1:1:1 ratio in the acupuncture group, control group, and sham acupuncture group. All the patients will receive basic treatment, and the patients in the acupuncture and sham acupuncture groups will also receive either acupuncture or sham acupuncture treatment, respectively, at six sessions each week for a 2 weeks period, followed by 3 months of follow-up. The primary outcome will be the change in the National Institute of Health Stroke Scale (NIHSS) scores after treatment. The secondary outcomes will include the Fugl-Meyer Assessment (FMA) scale scores and the Barthel Index (BI). Adverse events that occur during the trial will be documented. To discover differentially expressed proteins (DEPs) and their roles between the ACI subjects and healthy controls, we will also perform 4D-DIA quantitative proteomics analysis, and the DEPs will be confirmed by enzyme-linked immunosorbent assay (ELISA). This study was approved by the institutional review board of the First Teaching Hospital of Tianjin University of Traditional Chinese Medicine (TYLL2023043). Written informed consent from patients is required. This trial is registered in the Chinese Clinical Trial Registry (ChiCTR2300079204). Trial results will be published in a peer-reviewed academic journal.

Discussion

The results of this study will determine the preliminary efficacy and safety of acupuncture in ACI patients and whether the mechanism of this form of non-pharmacologic stimulation is mediated by a novel therapeutic target for neurorehabilitation through our proteomic analysis.

Clinical trial registration

https://www.chictr.org.cn, identifier ChiCTR2300079204.

Melanocortin Derivatives Induced Vascularization and Neuroglial Proliferation in the Rat Brain under Conditions of Cerebral Ischemia

Stroke remains the second leading cause of death worldwide. The development of new therapeutic agents focused on restoring vascular function and neuroprotection of viable tissues is required. In this study the neuroprotective activity of melanocortin-like ACTH(4-7)PGP and ACTH(6-9)PGP peptides was investigated in rat brain at 24 h after transient middle cerebral artery occlusion (tMCAO). The severity of ischemic damage, changes in the proliferative activity of neuroglial cells and vascularization of rat brain tissue were analyzed. The administration of peptides resulted in a significant increase in the volume density of neurons in the perifocal zone of infarction compared to rats subjected to ischemia and receiving saline. Immunohistochemical analysis of the proliferative activity of neuroglia cells using PCNA antibodies showed a significant increase in the number of proliferating cells in the penumbra and in the intact cerebral cortex of rats receiving peptide treatment. The effect of peptides on vascularization was examined using CD31 antibodies under tMCAO conditions, revealing a significant increase in the volume density of vessels and their sizes in the penumbra after administration of ACTH(4-7)PGP and ACTH(6-9)PGP. These findings confirm the neuroprotective effect of peptides due to the activation of neuroglia proliferation and the enhancement of collateral blood flow.

Ion Channel Dysregulation Following Intracerebral Hemorrhage

Injury to the brain after intracerebral hemorrhage (ICH) results from numerous complex cellular mechanisms. At present, effective therapy for ICH is limited and a better understanding of the mechanisms of brain injury is necessary to improve prognosis. There is increasing evidence that ion channel dysregulation occurs at multiple stages in primary and secondary brain injury following ICH. Ion channels such as TWIK-related K+ channel 1, sulfonylurea 1 transient receptor potential melastatin 4 and glutamate-gated channels affect ion homeostasis in ICH. They in turn participate in the formation of brain edema, disruption of the blood-brain barrier, and the generation of neurotoxicity. In this review, we summarize the interaction between ions and ion channels, the effects of ion channel dysregulation, and we discuss some therapeutics based on ion-channel modulation following ICH.

Mechanism of action and neuroprotective role of nicorandil in ischemic stroke

Nicorandil is a dual mechanism anti-anginal agent that acts as a nitric oxide (NO) donor and a potassium (K+) channel opener. Recent studies have evaluated the effect of nicorandil on ischemic stroke. Neurons have a low tolerance to hypoxia and therefore the brain tissue is significantly vulnerable to ischemia. Current approved treatments for ischemic stroke are tissue plasminogen activators and clot retrieval methods. The narrow therapeutic time window and lack of efficacy in restoring the dying neurons urge researchers to develop an alternative approach. In the terminal stages of anoxia, K+ channels induce hyperpolarization in various types of neuronal cells, leading to decreased neuronal activity and the preservation of the brain's energy. Nicorandil can open these K+ channels and sustain the hyperpolarization phase, which may have a neuroprotective effect during hypoxia. Additionally, we review how nicorandil can improve overall stroke outcomes through its anti-inflammatory, anti-oxidative, and edema-reducing effects. One of the major components evaluated in stroke patients is blood pressure. Studies have demonstrated that the effect of nicorandil on blood pressure is related to both its K+ channel opening and NO donating mechanisms. Since both hypertension and hypotension need correction before stroke intervention, it's crucial to consider the role of nicorandil and its impact on blood pressure. Previously published studies indicate that the right dosage of nicorandil can improve cerebral blood flow without significant changes in hemodynamic profiles. In this review, we discuss how nicorandil may contribute to better stroke outcomes based on previously published literature and laboratory findings.

Neuroprotective effects of exosomes derived from bone marrow mesenchymal stem cells treated by Musk Ketone on ischemic stroke

OBJECTIVES

Ischemic stroke (IS) is a leading cause of morbidity and mortality globally. This study aimed to investigate the role of exosomes (Exo) derived from bone marrow mesenchymal stem cells (BMSCs) treated with Musk Ketone (Mus treated-Exo) in the development of IS injury.

METHODS

BMSCs were pretreated with 10 μM Mus for 36 h, and Exo derived from these Mus-treated BMSCs (Mus-treated Exo) were extracted. Rats with middle cerebral artery occlusion (MCAO) were administered either 2 mg/kg of control Exo (Ctrl-Exo), 2 mg/kg of Mus treated-Exo, or 10 μM Mus. Neurological deficit and cerebral infarction in the MCAO rats were assessed utilizing neurological scores and TTC staining. Neuronal apoptosis, activation of microglia/macrophages, and inflammation were evaluated through TUNEL staining, immunofluorescence staining, and western blot analysis, respectively.

RESULTS

Our findings revealed that Mus-treated Exo possessed a more pronounced neuroprotective effect on MCAO rats when compared to Ctrl-Exo and Mus treatment alone. Specifically, Mus treated-Exo effectively ameliorated neurological function, reduced the volume of cerebral infarction, and diminished hemispheric swelling in MCAO rats. Moreover, it inhibited neuronal apoptosis and activation of microglia/macrophages, promoted the expression of the anti-apoptotic protein Bcl-2 while decreasing the expression of pro-apoptotic protein Bax, Cleaved-caspase 3, and pro-inflammatory factors IL-6 and COX-2.

CONCLUSIONS

The findings imply that Mus treated-Exo could confer neuroprotection in rats affected by IS, potentially by attenuating apoptosis and neuroinflammation. The underlying mechanisms, however, warrant further investigation. Mus treated-Exo shows potential as a new therapeutic strategy for IS.

Stroke and Neurogenesis: Bridging Clinical Observations to New Mechanistic Insights from Animal Models

Stroke was the 2nd leading cause of death and a major cause of morbidity. Unfortunately, there are limited means to promote neurological recovery post-stroke, but research has unearthed potential targets for therapies to encourage post-stroke neurogenesis and neuroplasticity. The occurrence of neurogenesis in adult mammalian brains, including humans, was not widely accepted until the 1990s. Now, adult neurogenesis has been extensively studied in human and mouse neurogenic brain niches, of which the subventricular zone of the lateral ventricles and subgranular zone of the dentate gyrus are best studied. Numerous other niches are under investigation for neurogenic potential. This review offers a basic overview to stroke in the clinical setting, a focused summary of recent and foundational research literature on cortical neurogenesis and post-stroke brain plasticity, and insights regarding how the meninges and choroid plexus have emerged as key players in neurogenesis and neuroplasticity in the context of focal cerebral ischemia disrupting the anterior circulation. The choroid plexus and meninges are vital as they are integral sites for neuroimmune interactions, glymphatic perfusion, and niche signaling pertinent to neural stem cells and neurogenesis. Modulating neuroimmune interactions with a focus on astrocyte activity, potentially through manipulation of the choroid plexus and meningeal niches, may reduce the exacerbation of stroke by inflammatory mediators and create an environment conducive to neurorecovery. Furthermore, addressing impaired glymphatic perfusion after ischemic stroke likely supports a neurogenic environment by clearing out inflammatory mediators, neurotoxic metabolites, and other accumulated waste. The meninges and choroid plexus also contribute more directly to promoting neurogenesis: the meninges are thought to harbor neural stem cells and are a niche amenable to neural stem/progenitor cell migration. Additionally, the choroid plexus has secretory functions that directly influences stem cells through signaling mechanisms and growth factor actions. More research to better understand the functions of the meninges and choroid plexus may lead to novel approaches for stimulating neuronal recovery after ischemic stroke.

A Promising Application of Injectable Hydrogels in Nerve Repair and Regeneration for Ischemic Stroke

Ischemic stroke, a condition that often leads to severe nerve damage, induces complex pathological and physiological changes in nerve tissue. The mature central nervous system (CNS) lacks intrinsic regenerative capacity, resulting in a poor prognosis and long-term neurological impairments. There is no available therapy that can fully restore CNS functionality. However, the utilization of injectable hydrogels has emerged as a promising strategy for nerve repair and regeneration. Injectable hydrogels possess exceptional properties, such as biocompatibility, tunable mechanical properties, and the ability to provide a supportive environment for cell growth and tissue regeneration. Recently, various hydrogel-based tissue engineering approaches, including cell encapsulation, controlled release of therapeutic factors, and incorporation of bioactive molecules, have demonstrated great potential in the treatment of CNS injuries caused by ischemic stroke. This article aims to provide a comprehensive review of the application and development of injectable hydrogels for the treatment of ischemic stroke-induced CNS injuries, shedding light on their therapeutic prospects, challenges, recent advancements, and future directions. Additionally, it will discuss the underlying mechanisms involved in hydrogel-mediated nerve repair and regeneration, as well as the need for further preclinical and clinical studies to validate their efficacy and safety.

A Review on Neuroinflammatory Pathway Mediating Through Ang-II/AT1 Receptors and a Novel Approach for the Treatment of Cerebral Ischemia in Combination with ARB's and Ceftriaxone

Background

Ischemic stroke is one of the prevalent neurodegenerative disorders; it is generally characterized by sudden abruption of blood flow due to thromboembolism and vascular abnormalities, eventually impairing the supply of oxygen and nutrients to the brain for its metabolic needs. Oxygen-glucose deprived conditions provoke the release of excessive glutamate, which causes excitotoxicity.

Summary

Recent studies suggest that circulatory angiotensin-II (Ang-II) has an imperative role in initiating detrimental events through binding central angiotensin 1 (AT1) receptors. Insufficient energy metabolites and essential ions often lead to oxidative stress during ischemic reperfusion, which leads to the release of proinflammatory mediators such as interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and cytokines like interleukin-18 (IL-18) and interleukin- 1beta (IL-1β). The transmembrane glutamate transporters, excitatory amino acid transporter-2 (EAAT-2), which express in astroglial cells, have a crucial role in the clearance of glutamate from its releasing site and convert glutamate into glutamine in normal circumstances of brain physiology.

Key Message

During cerebral ischemia, an impairment or dysfunction of EAAT-2 attributes the risk of delayed neuronal cell death. Earlier studies evidencing that angiotensin receptor blockers (ARB) attenuate neuroinflammation by inhibiting the Ang-II/AT1 receptor-mediated inflammatory pathway and that ceftriaxone ameliorates the excitotoxicity-induced neuronal deterioration by enhancing the transcription and expression of EAAT-2 via the nuclear transcriptional factor kappa-B (NF-kB) signaling pathway. The present review will briefly discuss the mechanisms involved in Ang-II/AT1-mediated neuroinflammation, ceftriaxone-induced EAAT-2 expression, and the repurposing hypothesis of the novel combination of ARBs and ceftriaxone for the treatment of cerebral ischemia.

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.

Therapeutic Potential of Myricetin in the Treatment of Neurological, Neuropsychiatric, and Neurodegenerative Disorders

Myricetin (MC), 3,5,7,3',4',5'-hexahydroxyflavone, chemically belongs to a flavonoid category known to confer antioxidant, antimicrobial, antidiabetic, and neuroprotective effects. MC is known to suppress the generation of Reactive Oxygen Species (ROS), lipid peroxidation (MDA), and inflammatory markers. It has been reported to improve insulin function in the human brain and periphery. Besides this, it modulates several neurochemicals including glutamate, GABA, serotonin, etc. MC has been shown to reduce the expression of the enzyme Mono Amine Oxidase (MAO), which is responsible for the metabolism of monoamines. MC treatment reduces levels of plasma corticosterone and restores hippocampal BDNF (full form) protein in stressed animals. Further, MC has shown its protective effect against amyloid-beta, MPTP, rotenone, 6-OHDA, etc. suggesting its potential role against neurodegenerative disorders. The aim of the present review is to highlight the therapeutic potential of MC in the treatment of several neurological, neuropsychiatric, and neurodegenerative disorders.

Neuroprotective Properties of Antiepileptics: What are the Implications for Psychiatric Disorders?

Since the discovery of the first antiepileptic compound, increasing attention has been paid to antiepileptic drugs (AEDs), and recently, with the understanding of the molecular mechanism underlying cells death, a new interest has revolved around a potential neuroprotective effect of AEDs. While many neurobiological studies in this field have focused on the protection of neurons, growing data are reporting how exposure to AEDs can also affect glial cells and the plastic response underlying recovery; however, demonstrating the neuroprotective abilities of AEDs remains a changeling task. The present work aims to summarize and review the literature available on the neuroprotective properties of the most commonly used AEDs. Results highlighted how further studies should investigate the link between AEDs and neuroprotective properties; while many studies are available on valproate, results for other AEDs are very limited and the majority of the research has been carried out on animal models. Moreover, a better understanding of the biological basis underlying neuro-regenerative defects may pave the way for the investigation of further therapeutic targets and eventually lead to an improvement in the actual treatment strategies.

Role of Microglia in Stroke

Ischemic stroke is a complex brain pathology caused by an interruption of blood supply to the brain. It results in neurological deficits which that reflect the localization and the size of the compromised brain area and are the manifestation of complex pathogenic events triggered by energy depletion. Inflammation plays a prominent role, worsening the injury in the early phase and influencing poststroke recovery in the late phase. Activated microglia are one of the most important cellular components of poststroke inflammation, appearing from the first few hours and persisting for days and weeks after stroke injury. In this chapter, we will discuss the nature of the inflammatory response in brain ischemia, the contribution of microglia to injury and regeneration after stroke, and finally, how ischemic stroke directly affects microglia functions and survival.

Molecular Hydrogen: Emerging Treatment for Stroke Management

Ischemic stroke is a major cause of death and disability worldwide. However, only intravenous thrombolysis using mechanical thrombectomy or tissue plasminogen activator is considered an effective and approved treatment. Molecular hydrogen is an emerging therapeutic agent and has recently become a research focus. Molecular hydrogen is involved in antioxidative, anti-inflammatory, and antiapoptotic functions in normal physical processes and may play an important role in stroke management; it has been evaluated in numerous preclinical and clinical studies in several administration formats, including inhalation of hydrogen gas, intravenous or intraperitoneal injection of hydrogen-enriched solution, or drinking of hydrogen-enriched water. In addition to investigation of the underlying mechanisms, the safety and efficacy of using molecular hydrogen have been carefully evaluated, and favorable outcomes have been achieved. All available evidence indicates that molecular hydrogen may be a promising treatment option for stroke management in the future. This review aimed to provide an overview of the role of molecular hydrogen in the management of stroke and possible further modifications of treatment conditions and procedures in terms of dose, duration, and administration route.

Expansion of plasma MicroRNAs over the first month following human stroke

Few have characterized miRNA expression during the transition from injury to neural repair and secondary neurodegeneration following stroke in humans. We compared expression of 754 miRNAs from plasma samples collected 5, 15, and 30 days post-ischemic stroke from a discovery cohort (n = 55) and 15-days post-ischemic stroke from a validation cohort (n = 48) to healthy control samples (n = 55 and 48 respectively) matched for age, sex, race and cardiovascular comorbidities using qRT-PCR. Eight miRNAs remained significantly altered across all time points in both cohorts including many described in acute stroke. The number of significantly dysregulated miRNAs more than doubled from post-stroke day 5 (19 miRNAs) to days 15 (50 miRNAs) and 30 (57 miRNAs). Twelve brain-enriched miRNAs were significantly altered at one or more time points (decreased expression, stroke versus controls: miR-107; increased expression: miR-99-5p, miR-127-3p, miR-128-3p, miR-181a-3p, miR-181a-5p, miR-382-5p, miR-433-3p, miR-491-5p, miR-495-3p, miR-874-3p, and miR-941). Many brain-enriched miRNAs were associated with apoptosis over the first month post-stroke whereas other miRNAs suggested a transition to synapse regulation and neuronal protection by day 30. These findings suggest that a program of decreased cellular proliferation may last at least 30 days post-stroke, and points to specific miRNAs that could contribute to neural repair in humans.

Regulated necrosis pathways: a potential target for ischemic stroke

Globally, ischemic stroke causes millions of deaths per year. The outcomes of ischemic stroke are largely determined by the amount of ischemia-related and reperfusion-related neuronal death in the infarct region. In the infarct region, cell injuries follow either the regulated pathway involving precise signaling cascades, such as apoptosis and autophagy, or the nonregulated pathway, which is uncontrolled by any molecularly defined effector mechanisms such as necrosis. However, numerous studies have recently found that a certain type of necrosis can be regulated and potentially modified by drugs and is nonapoptotic; this type of necrosis is referred to as regulated necrosis. Depending on the signaling pathway, various elements of regulated necrosis contribute to the development of ischemic stroke, such as necroptosis, pyroptosis, ferroptosis, pathanatos, mitochondrial permeability transition pore-mediated necrosis and oncosis. In this review, we aim to summarize the underlying molecular mechanisms of regulated necrosis in ischemic stroke and explore the crosstalk and interplay among the diverse types of regulated necrosis. We believe that targeting these regulated necrosis pathways both pharmacologically and genetically in ischemia-induced neuronal death and protection could be an efficient strategy to increase neuronal survival and regeneration in ischemic stroke.