Inflammatory mediators and stroke: new opportunities for novel therapeutics

Sevoflurane: an opportunity for stroke treatment

In developed countries, stroke is the leading cause of death and disability that affects long-term quality of life and its incidence is increasing. The incidence of ischemic stroke is much higher than that of hemorrhagic stroke. Ischemic stroke often leads to very serious neurological sequelae, which severely reduces the patients' quality of life and becomes a social burden. Therefore, ischemic stroke has received increasing attention. As a new type of anesthetic, sevoflurane has a lower solubility, works faster in the human body, and has less impact on the cardiovascular system than isoflurane. At the same time, studies have shown that preconditioning and postconditioning with sevoflurane have a beneficial effect on stroke. We believe that the role of sevoflurane in stroke may be a key area for future research. Therefore, this review mainly summarizes the relevant mechanisms of sevoflurane preconditioning and postconditioning in stroke in the past 20 years, revealing the bright prospects of sevoflurane in stroke treatment.

The impact of cytokines in neuroinflammation-mediated stroke

Cerebral stroke is ranked as the third most common contributor to global mortality and disability. The involvement of inflammatory mechanisms, both peripherally and within the CNS, holds significance in the pathophysiological cascades following the initiation of stroke. After the onset of acute stroke, predominantly ischemic, a subsequent phase of neuroinflammation ensues. It is a dual-effect process that not only exacerbates injury, leading to cell death, but paradoxically, it also serves a shielding role in facilitating recovery. Cytokines serve as pivotal mediators within the inflammatory cascade, actively contributing to the progression of ischemic damage. Stroke is followed by increased expression of pro-inflammatory cytokines including TNF-α, IL-1β, IL-6, etc. leading to the recruitment and stimulation of glial cells and peripheral leukocytes at the site of injury, promoting neuroinflammation. Cytokines can directly induce neuronal injury and death through various mechanisms, including excitotoxicity, oxidative stress, HPA-axis activation, secretion of matrix metalloproteinase and apoptosis. They can also amplify the inflammatory response, leading to further neuronal damage. Therapeutic strategies aimed at modulating cytokine release, immune response and cytokine signalling or activity are being explored as potential interventions to mitigate neuroinflammation and its detrimental effects in stroke. In this review, we have given a concise summary of our current knowledge of the function of various cytokines, brain inflammation and various signalling and molecular pathways including JAK/STAT3, TGF-β/Smad, MAPK, HMGB1/TLR and NF-κB modulated cytokines regulation in stroke. Therapeutic agents such as MCC950, genistein, edaravone, minocycline, etc. targeting various cytokines-associated signalling pathways have shown efficacy in preclinical and clinical trials reducing the pathophysiology of the illness were also addressed in this study.

Bibliometric analysis of research progress on tetramethylpyrazine and its effects on ischemia-reperfusion injury

In recent decades, natural products have attracted worldwide attention and become one of the most important resources for pharmacological industries and medical sciences to identify novel drug candidates for disease treatment. Tetramethylpyrazine (TMP) is an alkaloid extracted from Ligusticum chuanxiong Hort., which has shown great therapeutic potential in cardiovascular and cerebrovascular diseases, liver and renal injury, as well as cancer. In this review, we analyzed 1270 papers published on the Web of Science Core Collection from 2002 to 2022 and found that TMP exerted significant protective effects on ischemia-reperfusion (I/R) injury that is the cause of pathological damages in a variety of conditions, such as ischemic stroke, myocardial infarction, acute kidney injury, and liver transplantation. TMP is limited in clinical applications to some extent due to its rapid metabolism, a short biological half-life and poor bioavailability. Obviously, the structural modification, administration methods and dosage forms of TMP need to be further investigated in order to improve its bioavailability. This review summarizes the clinical applications of TMP, elucidates its potential mechanisms in protecting I/R injury, provides strategies to improve bioavailability, which presents a comprehensive understanding of the important compound. Hopefully, the information and knowledge from this review can help researchers and physicians to better improve the applications of TMP in the clinic.

Topiramate suppresses peri-infarct spreading depolarization and improves outcomes in a rat model of photothrombotic stroke

Ischemic stroke can cause depolarized brain waves, termed peri-infarct depolarization (PID). Here, we evaluated whether topiramate, a neuroprotective drug used to treat epilepsy and alleviate migraine, has the potential to reduce PID. We employed a rat model of photothrombotic ischemia that can reliably and reproducibly induce PID and developed a combined electrocorticography-laser speckle contrast imaging (ECoG-LSCI) platform to monitor neuronal activity and cerebral blood flow (CBF) simultaneously. Topiramate administration after photothrombotic ischemia did not rescue CBF but significantly restored somatosensory evoked potentials in the forelimb area of the primary somatosensory cortex. Moreover, infarct volume was investigated by 2,3,5-triphenyltetrazolium chloride (TTC) staining, and neuronal survival was evaluated by Nissl staining. Mechanistically, the levels of inflammatory markers, such as ED1 (CD68), Iba-1, and GFAP, decreased significantly after topiramate administration, as did BDNF expression, while the expression of NeuN and Bcl-2/Bax increased, which is indicative of reduced inflammation and improved neuroprotection.

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.

Implications of MMP-12 in the pathophysiology of ischaemic stroke

This article focuses on the emerging role of matrix metalloproteinase-12 (MMP-12) in ischaemic stroke (IS). MMP-12 expression in the brain increases dramatically in animal models of IS, and its suppression reduces brain damage and promotes neurological, sensorimotor and cognitive functional outcomes. Thus, MMP-12 could represent a potential target for the management of IS. This article provides an overview of MMP-12 upregulation in the brain following IS, its deleterious role in the post-stroke pathogenesis (blood-brain barrier disruption, inflammation, apoptosis and demyelination), possible molecular interactions and mechanistic insights, its involvement in post-ischaemic functional deficits and recovery as well as the limitations, perspectives, challenges and future directions for further research. Prior to testing any MMP-12-targeted therapy in patients with acute IS, additional research is needed to establish the effectiveness of MMP-12 suppression against IS in older animals and in animals with comorbidities. This article also examines the clinical implications of suppressing MMP-12 alone or in combination with MMP-9 for extending the currently limited tissue plasminogen activator therapy time window. Targeting of MMP-12 is expected to have a profound influence on the therapeutic management of IS in the future.

Molecular Mechanisms of Ischemic Stroke: A Review Integrating Clinical Imaging and Therapeutic Perspectives

Ischemic stroke poses a significant global health challenge, necessitating ongoing exploration of its pathophysiology and treatment strategies. This comprehensive review integrates various aspects of ischemic stroke research, emphasizing crucial mechanisms, therapeutic approaches, and the role of clinical imaging in disease management. It discusses the multifaceted role of Netrin-1, highlighting its potential in promoting neurovascular repair and mitigating post-stroke neurological decline. It also examines the impact of blood-brain barrier permeability on stroke outcomes and explores alternative therapeutic targets such as statins and sphingosine-1-phosphate signaling. Neurocardiology investigations underscore the contribution of cardiac factors to post-stroke mortality, emphasizing the importance of understanding the brain-heart axis for targeted interventions. Additionally, the review advocates for early reperfusion and neuroprotective agents to counter-time-dependent excitotoxicity and inflammation, aiming to preserve tissue viability. Advanced imaging techniques, including DWI, PI, and MR angiography, are discussed for their role in evaluating ischemic penumbra evolution and guiding therapeutic decisions. By integrating molecular insights with imaging modalities, this interdisciplinary approach enhances our understanding of ischemic stroke and offers promising avenues for future research and clinical interventions to improve patient outcomes.

The case for neuregulin-1 as a clinical treatment for stroke

Ischemic stroke is the leading cause of serious long-term disability and the 5th leading cause of death in the United States. Revascularization of the occluded cerebral artery, either by thrombolysis or endovascular thrombectomy, is the only effective, clinically-approved stroke therapy. Several potentially neuroprotective agents, including glutamate antagonists, anti-inflammatory compounds and free radical scavenging agents were shown to be effective neuroprotectants in preclinical animal models of brain ischemia. However, these compounds did not demonstrate efficacy in clinical trials with human patients following stroke. Proposed reasons for the translational failure include an insufficient understanding on the cellular and molecular pathophysiology of ischemic stroke, lack of alignment between preclinical and clinical studies and inappropriate design of clinical trials based on the preclinical findings. Therefore, novel neuroprotective treatments must be developed based on a clearer understanding of the complex spatiotemporal mechanisms of ischemic stroke and with proper clinical trial design based on the preclinical findings from specific animal models of stroke. We and others have demonstrated the clinical potential for neuregulin-1 (NRG-1) in preclinical stroke studies. NRG-1 significantly reduced ischemia-induced neuronal death, neuroinflammation and oxidative stress in rodent stroke models with a therapeutic window of >13 h. Clinically, NRG-1 was shown to be safe in human patients and improved cardiac function in multisite phase II studies for heart failure. This review summarizes previous stroke clinical candidates and provides evidence that NRG-1 represents a novel, safe, neuroprotective strategy that has potential therapeutic value in treating individuals after acute ischemic stroke.

Therapeutic effect of notoginseng saponins before and after fermentation on blood deficiency rats

Notoginseng saponins (NS) are the active ingredients in Panax notoginseng (Burk.) F.H. Chen (PN). NS can be transformed depending on how the extract is processed. Fermentation has been shown to produce secondary ginsenosides with increased bioavailability. However, the therapeutic effect of fermented NS (FNS) requires further study. The present study compared the compositions and activities of FNS and NS in blood deficiency rats, which resembles the symptoms of anemia in modern medicine, induced by acetylphenylhydrazine and cyclophosphamide. A total of 32 rats were randomly divided into control, model, FNS and NS groups. A blood deficiency model was established and then treatment was orally administered for 21 days. The results of component analysis indicated that some saponins transformed during the fermentation process resulting in a decrease of notoginsenoside R1, and ginsenosides Rg1, Rb1 and Re, and an increase in ginsenosides Rd, Rh2, compound K, protopanaxadiol and protopanaxatriol. The animal results showed that both FNS and NS increased the number of white blood cells (WBCs), red blood cells, hemoglobin, platelets and reticulocytes, and the levels of granulocyte-macrophage colony-stimulating factor (GM-CSF), erythropoietin (EPO) and thrombopoietin (TPO), decreased the G0/G1 phase and increased G2/M phase, and decreased the apoptosis rate of bone marrow (BM) cells, which suggested a contribution to the recovery of hematopoietic function of the BM cells. FNS and NS increased the protein expression levels of the cytokines IL-4, IL-10, IL-12, IL-13, TGF-β, IL-6, IFN-γ and TNF-α, and the mRNA expression levels of transcription factors GATA binding protein 3 and T-box expressed in T cell (T-bet). FNS and NS treatment also increased the number of CD4+ T cells, and decreased the enlargement of the rat spleen and thymus atrophy, which indicated a protective effect on the organs of the immune system. The results of the present study demonstrated that compared with NS, FNS showed an improved ability to increase the levels of WBCs, lymphocytes, GM-CSF, EPO, TPO, aspartate aminotransferase, IL-10, IL-12, IL-13 and TNF-α, and the mRNA expression levels of T-bet, and decrease alanine aminotransferase levels. The differences seen for FNS treatment could arise from their improved bioavailability compared with NS, due to the larger proportion of hydrophobic ginsenosides produced during fermentation.

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.

[Traumatic brain injury as risk factor of Alzheimer's disease and possibilities of pathogenetic therapy]

The article examines the potential role of brain mechanical damage as a trigger for the development of neurodegenerative changes. Attention is paid to dysfunction of the neurovascular unit, and disruption of the functional and compensatory capabilities of blood flow. The importance of microhemorrhages that occur in the acute period of injury and the formation of first focal and then diffuse neuroinflammation is emphasized. The importance of mitochondrial dysfunction was separately determined as a significant factor in increasing the risk of developing Alzheimer's disease (AD) in patients after traumatic brain injury (TBI). In TBI, there is a decrease in the expression of tight junction (TC) proteins of endothelial cells, such as occludin, claudin, JP, which leads to increased permeability of the blood-brain barrier. TBI, provoking endothelial dysfunction, contributes to the development of metabolic disorders of β-amyloid and tau protein, which in turn leads to worsening vascular damage, resulting in a vicious circle that can ultimately lead to the development of AD and dementia. Age-related changes in cerebral arteries, which impair perivascular transport of interstitial fluid, are currently considered as an important part of the «amyloid cascade», especially against the background of genetically mediated disorders of glial membranes associated with defective aquaporin-4 (encoded by the APOE4). Studies in animal models of TBI have revealed an increase in tau protein immunoreactivity and its phosphorylation, which correlates with the severity of injury. A comprehensive analysis of research results shows that the cascade of reactions triggered by TBI includes all the main elements of the pathogenesis of AD: disorders of energy metabolism, microcirculation and clearance of cerebral metabolic products. This leads to a disruption in the metabolism of amyloid protein and its accumulation in brain tissue with the subsequent development of tauopathy. Cerebrolysin, by modulating the permeability of the blood-brain barrier, blocks the development of neuroinflammation, reduces the accumulation of pathological forms of proteins and may be slow down the progression of neurodegeneration.

Interleukin-17: A Putative Novel Pharmacological Target for Pathological Pain

Pathological pain imposes a huge burden on the economy and the lives of patients. At present, drugs used for the treatment of pathological pain have only modest efficacy and are also plagued by adverse effects and risk for misuse and abuse. Therefore, understanding the mechanisms of pathological pain is essential for the development of novel analgesics. Several lines of evidence indicate that interleukin-17 (IL-17) is upregulated in rodent models of pathological pain in the periphery and central nervous system. Besides, the administration of IL-17 antibody alleviated pathological pain. Moreover, IL-17 administration led to mechanical allodynia which was alleviated by the IL-17 antibody. In this review, we summarized and discussed the therapeutic potential of targeting IL-17 for pathological pain. The upregulation of IL-17 promoted the development of pathological pain by promoting neuroinflammation, enhancing the excitability of dorsal root ganglion neurons, and promoting the communication of glial cells and neurons in the spinal cord. In general, the existing research shows that IL-17 is an attractive therapeutic target for pathologic pain, but the underlying mechanisms still need to be investigated.

Oral health and functional outcomes following mechanical thrombectomy for ischemic stroke

BACKGROUND

An association between poor dentition and the risk of ischemic stroke has previously been reported in the literature. In this study we assessed oral hygiene (OH), including tooth loss and the presence of dental disease, to determine if an association exists with functional outcomes following mechanical thrombectomy (MT) for large-vessel ischemic stroke.

METHODS

A retrospective review was conducted of consecutive adult patients at a single comprehensive stroke center who underwent MT from 2012 to 2018. Inclusion criteria included availability of CT imaging to radiographically assess OH. A multivariate analysis was performed, with the primary outcome being 90-day post-thrombectomy modified Rankin Scale (mRS) score >2.

RESULTS

A total of 276 patients met the inclusion criteria. The average number of missing teeth was significantly higher in patients with a poor functional outcome (mean (SD) 10 (11) vs 4 (6), p<0.001). The presence of dental disease was associated with poor functional outcome, including cavities (21 (27%) vs 13 (8%), p<0.001), periapical infection (18 (23%) vs 11 (6.7%), p<0.001), and bone loss (27 (35%) vs 11 (6.7%), p<0.001). Unadjusted, missing teeth was a univariate predictor of poor outcome (OR 1.09 (95% CI 1.06 to 1.13), p<0.001). After adjustment for recanalization scores and use of tissue plasminogen activator (tPA), missing teeth remained a predictor of poor outcome (OR 1.07 (95% CI 1.03 to 1.11), p<0.001).

CONCLUSION

Missing teeth and the presence of dental disease are inversely correlated with functional independence following MT, independent of thrombectomy success or tPA status.

From Stress to Sick(le) and Back Again-Oxidative/Antioxidant Mechanisms, Genetic Modulation, and Cerebrovascular Disease in Children with Sickle Cell Anemia

Sickle cell anemia (SCA) is a genetic disease caused by the homozygosity of the HBB:c.20A>T mutation, which results in the production of hemoglobin S (HbS). In hypoxic conditions, HbS suffers autoxidation and polymerizes inside red blood cells, altering their morphology into a sickle shape, with increased rigidity and fragility. This triggers complex pathophysiological mechanisms, including inflammation, cell adhesion, oxidative stress, and vaso-occlusion, along with metabolic alterations and endocrine complications. SCA is phenotypically heterogeneous due to the modulation of both environmental and genetic factors. Pediatric cerebrovascular disease (CVD), namely ischemic stroke and silent cerebral infarctions, is one of the most impactful manifestations. In this review, we highlight the role of oxidative stress in the pathophysiology of pediatric CVD. Since oxidative stress is an interdependent mechanism in vasculopathy, occurring alongside (or as result of) endothelial dysfunction, cell adhesion, inflammation, chronic hemolysis, ischemia-reperfusion injury, and vaso-occlusion, a brief overview of the main mechanisms involved is included. Moreover, the genetic modulation of CVD in SCA is discussed. The knowledge of the intricate network of altered mechanisms in SCA, and how it is affected by different genetic factors, is fundamental for the identification of potential therapeutic targets, drug development, and patient-specific treatment alternatives.

The Protective Effect of Citronellol against Doxorubicin-Induced Cardiotoxicity in Rats

Citronellol has been reported to have anti-inflammatory, anti-cancer, and antihypertensive activities, but its effect on myocardial ischemia is still unclear. The aim of this study was to investigate the therapeutic effects and pharmacological mechanisms of citronellol on ischemia. Therefore, a rat model of myocardial ischemia was established using the doxorubicin (DOX) model. To induce cardiotoxicity, the rats were given DOX (2.5 mg/kg) intraperitoneally over a 14-day period. Group I served as the control and received tween 80 (0.2%), group II received the vehicle and DOX, group III received the standard drug dexrazoxane and DOX, whereas groups IV, V, and VI were treated orally with citronellol (25, 50, and 100 mg/kg) and DOX, respectively. After treatment, the rats were euthanized, and blood samples were collected to assess the levels of serum cardiac markers, lipid profiles, and tissue antioxidant enzymes. The gene expressions of eNOS, PPAR-g, IL-10, VEGF, and NFkB-1 were also determined using real-time polymerase chain reactions. Simultaneous treatment with DOX and citronellol reduced cardiac antioxidant enzymes and lipid biomarkers in a dose-dependent manner. Citronellol also increased the expression of anti-inflammatory cytokines while reducing the expression of pro-inflammatory cytokines. Therefore, it can be concluded that citronellol may have potential cardioprotective effects in preventing DOX-induced cardiotoxicity.

Thymol abates the detrimental impacts of imidacloprid on rat brains by lessening oxidative damage and apoptotic and inflammatory reactions

Imidacloprid (IMID) is one of the most widely used neonicotinoid insecticides globally and, consequently, a probable widespread environmental contaminant. The potential neurotoxic effects of IMID have been previously reported. This study aimed to investigate the possible beneficial effect of thymol (TML) in relieving IMID-induced harmful effects on the brain of male Sprague-Dawley rats. For this aim, four groups (10 rats/group) were orally administered corn oil, TML (30 mg/kg b.wt), IMID (22.5 mg/kg b.wt), or TML + IMID for 56 days. The brain tissues were biochemically, histopathologically, and immunohistochemically evaluated. The results displayed that TML significantly restored the IMID-induced depletion of the total antioxidant capacity of the brain tissues. At the same time, the IMID-associated increased levels of lipid peroxidation in terms of malondialdehyde content were markedly suppressed in the TML + IMID group. Also, TML oral dosing markedly reduced the release of inflammatory elements, including nitric oxide and myeloperoxidase, resulting from IMID exposure. Furthermore, the IMID-induced decrease in gamma-aminobutyric acid but the increase in acetylcholinesterase was considerably reversed by TML oral dosing. Additionally, TML oral administration significantly counteracted the IMID-induced brainepatic DNA damage, as revealed by the comet assay. Besides, a significant downregulatibrainepatic Caspase-3 was evident in the TML + IMID group compared to the IMID group. However, TML oral dosing has not significantly altered the IMID-induced nuclear factor (NF-κB p65) increase. Therefore, TML could be a protective agent against IMID-induced detrimental impacts on brain tissue, possibly through its antioxidant, antiapoptotic, and anti-inflammatory activities.

Spatio-temporal Spread Variation through Myocardium in Supply and Demand Ischemia

In this paper, we investigate spatio-temporal progression of Myocardial ischemia (MI) and propose a metric for quantifying ischemic manifestation using cardiac activation time. Spatio-temporal spread is separately analyzed and compared for two different types of ischemia, namely 'Demand' and 'Supply' ischemia. This is done for both surface progression, along the epicardial surface as well as volume progression, along the three sub-myocardial layers. Cardiac activation time or depolarization time is computed from cardiac surface potential using a combined spatio-temporal derivative function. Ischemic zones in the cardiac surface is computed using Principal Component Analysis (PCA) and eigen vector projection of the depolarization time. Spatio-temporal ischemic spread analysis revealed different ischemic initiation and manifestation pattern for Demand and Supply ischemia, both in surface and volume progression.Clinical relevance Activation time based ischemic progression metric can serve as an alternate marker for ischemia detection and can provide more intuitive understanding on the pathological progression, and in turn assist in developing methods to prevent cell damage due to ischemic progression.

A comprehensive review of stroke-related signaling pathways and treatment in western medicine and traditional Chinese medicine

This review provides insight into the complex network of signaling pathways and mechanisms involved in stroke pathophysiology. It summarizes the historical progress of stroke-related signaling pathways, identifying potential interactions between them and emphasizing that stroke is a complex network disease. Of particular interest are the Hippo signaling pathway and ferroptosis signaling pathway, which remain understudied areas of research, and are therefore a focus of the review. The involvement of multiple signaling pathways, including Sonic Hedgehog (SHH), nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE), hypoxia-inducible factor-1α (HIF-1α), PI3K/AKT, JAK/STAT, and AMPK in pathophysiological mechanisms such as oxidative stress and apoptosis, highlights the complexity of stroke. The review also delves into the details of traditional Chinese medicine (TCM) therapies such as Rehmanniae and Astragalus, providing an analysis of the recent status of western medicine in the treatment of stroke and the advantages and disadvantages of TCM and western medicine in stroke treatment. The review proposes that since stroke is a network disease, TCM has the potential and advantages of a multi-target and multi-pathway mechanism of action in the treatment of stroke. Therefore, it is suggested that future research should explore more treasures of TCM and develop new therapies from the perspective of stroke as a network disease.

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

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

Neuroimmune mechanisms and therapies mediating post-ischaemic brain injury and repair

The nervous and immune systems control whole-body homeostasis and respond to various types of tissue injury, including stroke, in a coordinated manner. Cerebral ischaemia and subsequent neuronal cell death activate resident or infiltrating immune cells, which trigger neuroinflammation that affects functional prognosis after stroke. Inflammatory immune cells exacerbate ischaemic neuronal injury after the onset of brain ischaemia; however, some of the immune cells thereafter change their function to neural repair. The recovery processes after ischaemic brain injury require additional and close interactions between the nervous and immune systems through various mechanisms. Thus, the brain controls its own inflammation and repair processes after injury via the immune system, which provides a promising therapeutic opportunity for stroke recovery.

Engineered Mesenchymal Stem Cells Over-Expressing BDNF Protect the Brain from Traumatic Brain Injury-Induced Neuronal Death, Neurological Deficits, and Cognitive Impairments

Traumatic brain injury (TBI) causes transitory or permanent neurological and cognitive impairments, which can intensify over time due to secondary neuronal death. However, no therapy currently exists that can effectively treat brain injury following TBI. Here, we evaluate the therapeutic potential of irradiated engineered human mesenchymal stem cells over-expressing brain-derived neurotrophic factor (BDNF), which we denote by BDNF-eMSCs, in protecting the brain against neuronal death, neurological deficits, and cognitive impairment in TBI rats. BDNF-eMSCs were administered directly into the left lateral ventricle of the brain in rats that received TBI damage. A single administration of BDNF-eMSCs reduced TBI-induced neuronal death and glial activation in the hippocampus, while repeated administration of BDNF-eMSCs reduced not only glial activation and delayed neuronal loss but also enhanced hippocampal neurogenesis in TBI rats. In addition, BDNF-eMSCs reduced the lesion area in the damaged brain of the rats. Behaviorally, BDNF-eMSC treatment improved the neurological and cognitive functions of the TBI rats. The results presented in this study demonstrate that BDNF-eMSCs can attenuate TBI-induced brain damage through the suppression of neuronal death and increased neurogenesis, thus enhancing functional recovery after TBI, indicating the significant therapeutic potential of BDNF-eMSCs in the treatment of TBI.

Epigallocatechin gallate restores the reduction of protein phosphatase 2 A subunit B caused by middle cerebral artery occlusion

BACKGROUND

Epigallocatechin gallate (EGCG) is a flavonoid compound commonly found in green tea. It exhibits antioxidant, anti-inflammatory, and neuroprotective effects in cerebral ischemia. Protein phosphatase 2 A (PP2A) is an important serine/threonine phosphatase enzyme involved in various cellular activities. PP2A subunit B is present abundantly in the brain and plays an important role in the nervous system. We investigated the effect of EGCG on the expression level of PP2A subunit B in cerebral ischemia caused by middle cerebral artery occlusion (MCAO). EGCG (50 mg/kg) or vehicle was injected into the peritoneal cavity prior to MCAO surgery. Neurological behavior tests were performed 24 h after MCAO, and right cerebral cortex tissue was collected. Cerebral ischemia caused serious neurological abnormalities, which were alleviated by EGCG administration. We screened the expression of PP2A subunits containing A, B, and C using reverse-transcription PCR. We confirmed that PP2A subunit B exhibited significant changes in MCAO animals compared to subunits A and C. We continuously examined the expression of PP2A subunit B protein in MCAO animals using Western blot analysis.

RESULTS

EGCG alleviated the reduction of PP2A subunit B protein by MCAO damage. In addition, immunohistochemistry demonstrated a decrease in the number of PP2A subunit B-positive cells in the cerebral cortex, and EGCG attenuated this decrease. Maintenance of PP2A subunit B is important for normal brain function.

CONCLUSION

Therefore, our findings suggest that EGCG exerts neuroprotective effects against cerebral ischemia through modulation of PP2A subunit B expression.

Carvacrol Inhibits Expression of Transient Receptor Potential Melastatin 7 Channels and Alleviates Zinc Neurotoxicity Induced by Traumatic Brain Injury

Carvacrol is a monoterpenoid phenol produced by aromatic plants such as oregano. Although the exact mechanism by which carvacrol acts has not yet been established, it appears to inhibit transient receptor potential melastatin 7 (TRPM7), which modulates the homeostasis of metal ions such as zinc and calcium. Several studies have demonstrated that carvacrol has protective effects against zinc neurotoxicity after ischemia and epilepsy. However, to date, no studies have investigated the effect of carvacrol on traumatic brain injury (TBI)-induced zinc neurotoxicity. In the present study, we investigated the therapeutic potential of carvacrol for the prevention of zinc-induced neuronal death after TBI. Rats were subjected to a controlled cortical impact, and carvacrol was injected at a dose of 50 mg/kg. Histological analysis was performed at 12 h, 24 h, and 7 days after TBI. We found that carvacrol reduced TBI-induced TRPM7 over-expression and free zinc accumulation. As a result, subsequent oxidative stress, dendritic damage, and neuronal degeneration were decreased. Moreover, carvacrol not only reduced microglial activation and delayed neuronal death but also improved neurological outcomes after TBI. Taken together, these findings suggest that carvacrol administration may have therapeutic potential after TBI by preventing neuronal death through the inhibition of TRPM7 expression and alleviation of zinc neurotoxicity.

Quantitative Analyses and Validation of Phospholipids and Sphingolipids in Ischemic Rat Brains

Prior MALDI mass spectrometry imaging (MALDI-MSI) studies reported significant changes in phosphatidylcholines (PCs), lysophosphatidylcholines (LPCs), and sphingomyelins (SMs) in ischemic rat brains yet overlooked the information on other classes of PLs and SLs and provided very little or no validation on the detected lipid markers. Relative quantitation of four classes of PLs and two classes of SLs in the ischemic and normal temporal cortex (TCX), parietal cortex (PCX), and striatum (ST) of rats was performed with hydrophilic interaction chromatography (HILIC)-tandem mass spectrometry (MS/MS) analyses, and the marker lipid species was identified by multivariate data analysis and validated with additional tissue cohorts. The acquired lipid information was sufficient in differentiating individual anatomical regions under different pathological states, identifying region-specific ischemic brain lipid markers and revealing additional PL and SL markers not reported previously. Validation of orthogonal partial least square discriminating analysis (OPLS-DA) identified ischemic brain lipid markers yielded much higher classification accuracy, precision, specificity, sensitivity, and lower false positive and false negative rates than those from the volcano plot analyses using conventional statistical significance and a fold change of two as the cutoff and provided a wider prospective to ischemia-associated brain lipid changes.

Chrysophanol facilitates long-term neurological recovery through limiting microglia-mediated neuroinflammation after ischemic stroke in mice

BACKGROUND

Inflammation plays an important role in ischemic brain injury and affects brain recovery and neuroplasticity. Chrysophanol (CHR), has attracted attention for its protective effects through immunomodulatory and anti-inflammatory properties. However, the effect of CHR for brain recovery and neuroplasticity is not clear. The current study aimed to investigate the effect of CHR in the chronic phase of stroke in mice, and to elucidate the underlying mechanisms.

METHODS

C57BL/6 mice were subjected to treatment with Vehicle or CHR immediately through intraperitoneal injection daily for 14 d after distal middle cerebral artery occlusion (dMCAO). Neurological deficits were monitored up to 28 days after stroke. Nissl and Golgi stain, neural plasticity, and microglia-associated inflammatory cytokines were detected. Primary cortical neuron and BV2 microglia cell lines were employed to explore the underlying mechanism in vitro.

RESULTS

Compared with Vehicle group, CHR mitigated the histological damage, facilitated the neural plasticity and improved the neurological function up to 4 weeks after stroke. In vitro, CHR promoted the complexity of neurons and the spine density by modulating microglial polarization and reducing the expression of microglia-associated inflammatory cytokines, especially IL-6. In vivo, microglia activation and inflammatory cytokines were significantly increased after dMCAO and downregulated by CHR. Further investigation showed STAT3 is the major downstream effector of IL-6 signaling.

CONCLUSIONS

CHR ameliorated microenvironment for neural plasticity and exhibited neuroprotection via arresting microglia toward pro-inflammatory phenotype and downregulation of the expressions of pro-inflammatory cytokines, especially of IL-6. IL-6-STAT3 signaling might be CHR's therapeutic target for neuroinflammatory responses after stroke.

Molecular Mechanism of Epimedium Extract against Ischemic Stroke Based on Network Pharmacology and Experimental Validation

Ischemic stroke exhibits high morbidity, disability, and mortality, and treatments for ischemic stroke are limited despite intensive research. The potent neuroprotective benefits of Epimedium against ischemic stroke have gained lots of interest. Nevertheless, systematic research on the direct role and mechanisms of Epimedium in ischemic stroke is still lacking. Network pharmacology analysis coupled with experimental verification was utilized to systematically evaluate the potential pharmacological mechanism of Epimedium against ischemic stroke. The TCMSP database was used to mine the bioactive ingredients and Epimedium's targets. The DrugBank, OMIM, and GeneCards databases were employed to identify potential targets of ischemic stroke. GO and KEGG pathway analyses were also carried out. The interaction between active components and hub targets was confirmed via molecular docking. An experimental ischemic stroke model was used to evaluate the possible therapeutic mechanism of Epimedium. As a result, 23 bioactive compounds of Epimedium were selected, and 30 hub targets of Epimedium in its function against ischemic stroke were identified, and molecular docking results demonstrated good binding. The IL-17 signaling pathway was revealed as a potentially significant pathway, with the NF-κB and MAPK/ERK signaling pathways being involved. Furthermore, in vivo experiments demonstrated that Epimedium treatment could improve neurological function and reduce infarct volume. Additionally, Epimedium reduced the activation of microglia and astrocytes in both the ischemic penumbra of the hippocampus and cerebral cortex following ischemic stroke. Western blot and RT-qPCR analyses demonstrated that Epimedium not only depressed the expression of IL-1β, TNF-α, IL-6, and IL-4 but also inhibited the NF-κB and MAPK/ERK signaling pathways. This study applied network pharmacology and in vivo experiment to explore possible mechanism of Epimedium's role against ischemic stroke, which provides insight into the treatment of ischemic stroke.

Photobiomodulation for the treatment of neuroinflammation: A systematic review of controlled laboratory animal studies

Background

Neuroinflammation is a response that involves different cell lineages of the central nervous system, such as neurons and glial cells. Among the non-pharmacological interventions for neuroinflammation, photobiomodulation (PBM) is gaining prominence because of its beneficial effects found in experimental brain research. We systematically reviewed the effects of PBM on laboratory animal models, specially to investigate potential benefits of PBM as an efficient anti-inflammatory therapy.

Methods

We conducted a systematic search on the bibliographic databases (PubMed and ScienceDirect) with the keywords based on MeSH terms: photobiomodulation, low-level laser therapy, brain, neuroinflammation, inflammation, cytokine, and microglia. Data search was limited from 2009 to June 2022. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. The initial systematic search identified 140 articles. Among them, 54 articles were removed for duplication and 59 articles by screening. Therefore, 27 studies met the inclusion criteria.

Results

The studies showed that PBM has anti-inflammatory properties in several conditions, such as traumatic brain injury, edema formation and hyperalgesia, ischemia, neurodegenerative conditions, aging, epilepsy, depression, and spinal cord injury.

Conclusion

Taken together, these results indicate that transcranial PBM therapy is a promising strategy to treat brain pathological conditions induced by neuroinflammation.

Intermittent hypoxia promotes the recovery of motor function in rats with cerebral ischemia by regulating mitochondrial function

Hypoxia preconditioning is neuroprotective, but the therapeutic effects of intermittent hypoxia were not fully considered. The present study investigated the neuroprotective effect and mechanism of intermittent hypoxia on motor function after cerebral ischemia and explored alternative clinical treatment options. In total, 36 8-week-old male Sprague-Dawley rats were subjected to 60 min of transient middle cerebral artery occlusion (tMCAO) and then randomly divided into a sham-operated group (SHAM), tMCAO-sedentary group (SED), and tMCAO-intermittent hypoxia group (IH). The intervention was performed 1 week after tMCAO and lasted 4 weeks. Rats in the IH group were placed in an animal hypoxic chamber (altitude 5000 m and oxygen concentration of 13%) for 4 h/day and 7 days/week, and rats in the SED group were placed in a normoxic environment for 4 weeks. Body weights, neurological deficit scores, cerebral infarction volume ratios, gait analyses, mitochondrial structure, adenosine triphosphate (ATP) content and AMO-activated protein kinase (AMPK), peroxisome proliferator-activated receptor γ co-activator-1α (PGC-1α), and silencing regulatory protein 3 (Sirt3) expression in the peri-ischemic region brain tissues were detected during the intervention. Compared with the SED group, the body weight of the IH group gradually recovered, and the neurological deficit scores were significantly reduced (P < 0.05). The gait analysis results showed that the pressure of the affected paw and the maximum content area, swing speed, stride length, and other parameters were significantly restored (P < 0.05). The cerebral infarction volume ratio was significantly reduced (P < 0.01). Mitochondrial morphological structure damage in the peri-ischemic region brain tissues recovered, the number was significantly increased (P < 0.05), and the expression of AMPK, PGC-1α, and Sirt3 proteins (P < 0.05), and ATP content were significantly increased (P < 0.05). Intermittent hypoxia may activate the AMPK-PGC-1α-Sirt3 signaling pathway, promote mitochondrial biogenesis, repair mitochondrial ultrastructural damage, and improve mitochondrial function to reduce brain damage and promote motor function recovery in rats with cerebral ischemia.

Signaling pathways involved in ischemic stroke: molecular mechanisms and therapeutic interventions

Ischemic stroke is caused primarily by an interruption in cerebral blood flow, which induces severe neural injuries, and is one of the leading causes of death and disability worldwide. Thus, it is of great necessity to further detailly elucidate the mechanisms of ischemic stroke and find out new therapies against the disease. In recent years, efforts have been made to understand the pathophysiology of ischemic stroke, including cellular excitotoxicity, oxidative stress, cell death processes, and neuroinflammation. In the meantime, a plethora of signaling pathways, either detrimental or neuroprotective, are also highly involved in the forementioned pathophysiology. These pathways are closely intertwined and form a complex signaling network. Also, these signaling pathways reveal therapeutic potential, as targeting these signaling pathways could possibly serve as therapeutic approaches against ischemic stroke. In this review, we describe the signaling pathways involved in ischemic stroke and categorize them based on the pathophysiological processes they participate in. Therapeutic approaches targeting these signaling pathways, which are associated with the pathophysiology mentioned above, are also discussed. Meanwhile, clinical trials regarding ischemic stroke, which potentially target the pathophysiology and the signaling pathways involved, are summarized in details. Conclusively, this review elucidated potential molecular mechanisms and related signaling pathways underlying ischemic stroke, and summarize the therapeutic approaches targeted various pathophysiology, with particular reference to clinical trials and future prospects for treating ischemic stroke.

Role of uroguanylin's signaling pathway in the development of ischemic stroke

Stroke is one of the leading causes of mortality and disability worldwide. By affecting bradykinin function, activation of guanylate cyclase (GC)‐A has been shown to have a neuroprotective effect after ischaemic stroke, whereas the same has not been confirmed for GC‐B; therefore, we aimed to determine the possible role of GC‐C and its agonist, uroguanylin (UGN), in the development of stroke. In this study, middle cerebral artery occlusion (MCAO) was performed on wild‐type (WT), GC‐C KO and UGN KO mice. MR images were acquired before and 24 h after MCAO. On brain slices 48 h after MCAO, the Ca²⁺ response to UGN stimulation was recorded. Our results showed that the absence of GC‐C in GC‐C KO mice resulted in the development of smaller ischaemic lesions compared with WT littermates, which is an opposite effect compared with the effects of GC‐A agonists on brain lesions. WT and UGN KO animals showed a stronger Ca²⁺ response upon UGN stimulation in astrocytes of the peri‐ischaemic cerebral cortex compared with the same cortical region of the unaffected contralateral hemisphere. This stronger activation was not observed in GC‐C KO animals, which may be the reason for smaller lesion development in GC‐C KO mice. The reason why GC‐C might affect Ca²⁺ signalling in peri‐ischaemic astrocytes is that GC‐C is expressed in these cells after MCAO, whereas under normoxic conditions, it is expressed mainly in cortical neurons. Stronger activation of the Ca²⁺‐dependent signalling pathway could lead to the stronger activation of the Na⁺/H⁺ exchanger, tissue acidification and neuronal death.

Moderating effect of ppar-γ on the association of c-reactive protein and ischemic stroke in patients younger than 60

AIM

The aim of this study was to evaluate the moderating effect of peroxisome proliferator activated receptor-γ (PPAR-γ) gene variants on the association of serum C-reactive protein level (CRP) and ischemic stroke (IS).

MATERIAL AND METHODS

A total of 114 patients with IS and 135 healthy controls were included.

RESULTS

After adjustment for age, sex, total cholesterol, LDL and HDL cholesterol, triglycerides, hypertension, smoking, body mass index and previous therapy with antihypertensive and/or statins, PPAR-γ had statistically significant moderating effect on association of serum CRP level and IS in patients younger than 60. In participants with PPAR CG or GG genotype level of CRP and IS were not statistically significantly associated (OR = 1.00; 95% CI 0.90-1.10; p = 0.933), but in participants with PPAR CC genotype, the association of serum CRP level and IS was significant (OR = 1.67; 95% CI 1.21-2.31; p = 0.002).

CONCLUSION

In patients with PPAR CC genotype the association of serum CRP level and IS was significant.

Stem Cell Transplantation Therapy and Neurological Disorders: Current Status and Future Perspectives

Neurodegenerative diseases are a global health issue with inadequate therapeutic options and an inability to restore the damaged nervous system. With advances in technology, health scientists continue to identify new approaches to the treatment of neurodegenerative diseases. Lost or injured neurons and glial cells can lead to the development of several neurological diseases, including Parkinson's disease, stroke, and multiple sclerosis. In recent years, neurons and glial cells have successfully been generated from stem cells in the laboratory utilizing cell culture technologies, fueling efforts to develop stem cell-based transplantation therapies for human patients. When a stem cell divides, each new cell has the potential to either remain a stem cell or differentiate into a germ cell with specialized characteristics, such as muscle cells, red blood cells, or brain cells. Although several obstacles remain before stem cells can be used for clinical applications, including some potential disadvantages that must be overcome, this cellular development represents a potential pathway through which patients may eventually achieve the ability to live more normal lives. In this review, we summarize the stem cell-based therapies that have been explored for various neurological disorders, discuss the potential advantages and drawbacks of these therapies, and examine future directions for this field.

The Kynurenine Pathway and Kynurenine 3-Monooxygenase Inhibitors

Under normal physiological conditions, the kynurenine pathway (KP) plays a critical role in generating cellular energy and catabolizing tryptophan. Under inflammatory conditions, however, there is an upregulation of the KP enzymes, particularly kynurenine 3-monooxygenase (KMO). KMO has garnered much attention due to its production of toxic metabolites that have been implicated in many diseases and disorders. With many of these illnesses having an inadequate or modest treatment, there exists a need to develop KMO inhibitors that reduce the production of these toxic metabolites. Though prior efforts to find an appropriate KMO inhibitor were unpromising, the development of a KMO crystal structure has provided the opportunity for a rational structure-based design in the development of inhibitors. Therefore, the purpose of this review is to describe the kynurenine pathway, the kynurenine 3-monooxygenase enzyme, and KMO inhibitors and their potential candidacy for clinical use.

TRPM2 in ischemic stroke: Structure, molecular mechanisms, and drug intervention

Ischemic stroke has a high lethality rate worldwide, and novel treatments are limited. Calcium overload is considered to be one of the mechanisms of cerebral ischemia. Transient receptor potential melastatin 2 (TRPM2) is a reactive oxygen species (ROS)-sensitive calcium channel. Cerebral ischemia-induced TRPM2 activation triggers abnormal intracellular Ca2+ accumulation and cell death, which in turn causes irreversible brain damage. Thus, TRPM2 has emerged as a new therapeutic target for ischemic stroke. This review provides data on the expression, structure, and function of TRPM2 and illustrates its cellular and molecular mechanisms in ischemic stroke. Natural and synthetic TRPM2 inhibitors (both specific and nonspecific) are also summarized. The three-dimensional protein structure of TRPM2 has been identified, and we speculate that molecular simulation techniques will be essential for developing new drugs that block TRPM2 channels. These insights about TRPM2 may be the key to find potent therapeutic approaches for the treatment of ischemic stroke.

Inflammatory Cytokines are in Action: Brain Plasticity and Recovery after Brain Ischemia Due to Delayed Melatonin Administration

OBJECTIVES

Post-ischemic inflammation leads to apoptosis as an indirect cause of functional disabilities after the stroke. Melatonin may be a good candidate for the stroke recovery because of its anti-inflammatory effects. Therefore, we investigated the effect of melatonin on inflammation in the functional recovery of brain by evaluating ipsilesional and contralesional alterations.

MATERIALS AND METHODS

Melatonin (4 mg/kg/day) was intraperitoneally administered into the mice from the 3^rd to the 55^th day of the post-ischemia after 30 min of middle cerebral artery occlusion.

RESULTS

Melatonin produced a functional recovery by reducing the emigration of the circulatory leukocytes and the local microglial activation within the ischemic brain. Overall, the expression of the inflammation-related genes reduced upon melatonin treatment in the ischemic hemisphere. On the other hand, the expression level of the inflammatory cytokine genes raised in the contralateral hemisphere at the 55^th day of the post-ischemia. Furthermore, melatonin triggers an increase in the iNOS expression and a decrease in the nNOS expression in the ipsilateral hemisphere at the earlier times in the post-ischemic recovery. At the 55^th day of the post-ischemic recovery, melatonin administration enhanced the eNOS and nNOS protein expressions.

CONCLUSIONS

The present molecular, biological, and histological data have revealed broad anti-inflammatory effects of melatonin in both hemispheres with distinct temporal and spatial patterns at different phases of post-stroke recovery. These outcomes also established that melatonin act recruitment of contralesional rather than of ipsilesional.

Nitro-oleic acid-mediated blood-brain barrier protection reduces ischemic brain injury

Nitro-oleic acid (OA-NO₂), a nitroalkene formed in nitric oxide-dependent oxidative reactions, has been found in human plasma and is thought to regulate pathophysiological functions. Recently, accumulating evidence suggests that OA-NO₂ may function as an anti-inflammatory mediator, and ameliorate the progression of diabetes and cardiovascular diseases. However, the role of OA-NO₂ in ischemic brain injury remains unexplored. In this study, C57BL/6 mice were subjected to 1 h transient middle cerebral artery occlusion (MCAO) and followed by 1- 7 days of reperfusion. These mice were treated with vehicle, OA, or OA-NO₂ (10 mg/kg) via tail vein injection at 2 h after the onset of MCAO. Our results show that intravenous administration of OA-NO₂ led to reduced BBB leakage in ischemic brains, reduced brain infarct, and improved sensorimotor functions in response to ischemic insults when compared to OA and vehicle controls. Also, OA-NO₂ significantly reduced BBB leakage-triggered infiltration of neutrophils and macrophages in the ischemic brains. Moreover, OA-NO₂ treatment reduced the M1-type microglia and increased M2-type microglia. Mechanistically, OA-NO₂ alleviated the decline of mRNA and protein level of major endothelial TJs including ZO-1 in stroke mice. Treatment of OA-NO₂ also significantly inhibited stroke-induced inflammatory mediators, iNOS, E-selectin, P-selectin, and ICAM1, in mouse brains. In conclusion, OA-NO₂ preserves BBB integrity and confers neurovascular protection in ischemic brain damage. OA-NO₂-mediated brain protection may help us to develop a novel therapeutic strategy for the treatment of ischemic stroke.

Interleukin-6: A Novel Target for Cardio-Cerebrovascular Diseases

Cardio-Cerebrovascular Disease is a collective term for cardiovascular disease and cerebrovascular disease, being a serious threat to human health. A growing number of studies have proved that the content of inflammatory factors or mediators determines the stability of vascular plaque and the incidence of cardio-cerebrovascular event, and involves in the process of Cardio-Cerebrovascular Diseases. Interleukin-6 is a widely used cytokine that causes inflammation and oxidative stress, which would further result in cardiac and cerebral injury. The increased expression of interleukin-6 is closely related to atherosclerosis, myocardial infarction, heart failure and ischemic stroke. It is a key risk factor for these diseases by triggering inflammatory reaction and inducing other molecules release. Therefore, interleukin-6 may become a potential target for Cardio-Cerebrovascular Diseases in the future. This paper is aimed to discuss the expression changes and pathological mechanisms of interleukin-6 in Cardio-Cerebrovascular Diseases, and to provide a novel strategy for the prevention and treatment of Cardio-Cerebrovascular Diseases.

Nutritional Supplementation of Naturally Occurring Vitamin D to Improve Hemorrhagic Stroke Outcomes

Vitamin D deficiency, if left untreated, is associated with bone disorders, cardiovascular damage, and an increased risk of ischemic stroke. While there are various nutritional options for the natural intake of vitamin D, we hope to elucidate the potential mechanisms dietary vitamin D may play in hemorrhagic stroke pathology. This scoping review outlines findings from studies relevant to the biochemical activity of vitamin D, the impact of vitamin D deficiency on hemorrhagic stroke outcomes, and the potential benefit of nutritional vitamin D on hemorrhagic stroke outcomes. Here, we analyze the relevant factors that can lead to vitamin D deficiency, and subsequently, a higher risk of hemorrhagic stroke incidence with worsened subsequent outcomes. The neuroprotective mechanisms through which vitamin D works to attenuate hemorrhagic stroke onset and post-stroke outcomes have not yet been thoroughly examined. However, researchers have proposed several potential protective mechanisms, including reduction of blood brain barrier disturbance by inhibiting the production of reactive oxygen species, mitigation of inflammation through a reduction of levels of proinflammatory cytokines, and prevention of cerebral vasospasm and delayed cerebral ischemia following subarachnoid hemorrhage and intracerebral hemorrhage. While more research is needed and there are limitations to vitamin D supplementation, vitamin D as a whole may play a significant role in the dynamics of hemorrhagic stroke. Further research should focus on expanding our understanding of the neuroprotective capacity and mechanisms of vitamin D, as well as how vitamin D supplementation could serve as an effective course of treatment of hemorrhagic strokes.

Role of Interleukin-1 Receptor-Like 1 (ST2) in Cerebrovascular Disease

Following both ischemic and hemorrhagic stroke, innate immune cells initiate a proinflammatory response that further exacerbate tissue injury in the acute phase, but these cells also play an important reparative role thereafter. Numerous cytokines and signaling pathways have been implicated in driving the deleterious proinflammatory response, but less is known about the mediators that connect the initial vascular injury to the systemic immune response and the relationship between proinflammatory and reparative immune responses. The Interleukin-33 (IL-33) and serum stimulation-2 (ST2) axis is an interleukin signaling pathway that is a prime candidate to fulfill this role. In this review, we describe the biology of the IL-33/ST2 system, present evidence that its soluble decoy receptor, soluble ST2 (sST2), plays a key role in secondary neurologic injury after stroke, and discuss this in the context of the known role of IL-33/ST2 in other disease.

C-Reactive Protein Levels and Clinical Prognosis in LAA-Type Stroke Patients: A Prospective Cohort Study

Methods

We prospectively included 200 patients with LAA-type AIS and tested their CRP levels on admission. We followed these patients consecutively. The primary outcome was an adverse event, defined as a modified Rankin Scale score of 2-6 at months 3, 6, and 12 after discharge. A logistic regression model was used to analyze the relationship between CRP and the functional outcome of LAA stroke.

Results

We divided 200 patients into 3 groups evenly based on CRP level. After adjustment for gender, age, smoking history, drinking history, history of hyperlipidemia, history of diabetes, lipid levels, and blood glucose levels, logistic regression showed that the incidence of LAA-type AIS poor outcome was positively associated with CRP level at admission, whether it was 3 months, 6 months, or 12 months after discharge, respectively (OR: 2.574, 95% CI: 1.213-5.463; OR: 2.806, 95% CI: 1.298-6.065; OR: 2.492, 95% CI: 1.167-5.321. In the highest tertile vs. the lowest tertile as a reference), and both were statistically different.

Conclusions

High CRP level predicts poor functional outcome in LAA-type AIS patients, which provides a strong basis for clinicians to make treatment decisions for these patients.

Therapeutic Potential of Cytokines in Demyelinating Lesions After Stroke

White matter damage is a component of most human stroke and usually accounts for at least half of the lesion volume. Subcortical white matter stroke (WMS) accounts for 25% of all strokes and causes severe motor and cognitive dysfunction. The adult brain has a very limited ability to repair white matter damage. Pathological analysis shows that demyelination or myelin loss is the main feature of white matter injury and plays an important role in long-term sensorimotor and cognitive dysfunction. This suggests that demyelination is a major therapeutic target for ischemic stroke injury. An acute inflammatory reaction is triggered by brain ischemia, which is accompanied by cytokine production. The production of cytokines is an important factor affecting demyelination and myelin regeneration. Different cytokines have different effects on myelin damage and myelin regeneration. Exploring the role of cytokines in demyelination and remyelination after stroke and the underlying molecular mechanisms of demyelination and myelin regeneration after ischemic injury is very important for the development of rehabilitation treatment strategies. This review focuses on recent findings on the effects of cytokines on myelin damage and remyelination as well as the progress of research on the role of cytokines in ischemic stroke prognosis to provide a new treatment approach for amelioration of white matter damage after stroke.

Hypothermia Protects Mice Against Ischemic Stroke by Modulating Macrophage Polarization Through Upregulation of Interferon Regulatory Factor-4

Background

Therapeutic hypothermia (TH) has been proven to be protective in ischemic stroke (IS) due to its anti-inflammatory capacity. Recently, the interferon regulatory factor 4 (IRF4) has been characterized as a central regulator of neuroinflammation in IS. Here we aim to determine whether IFR4 contributes to the neuroprotective effects of TH in IS.

Methods

In the present study, IRF4 knockout (IRF4^−/-) and wild-type (IRF4^+/+) mice were treated with or without TH after IS. Cerebral IRF4 expression, the production of pro-inflammatory and anti-inflammatory cytokines and macrophage polarization were determined at 8 hours after reperfusion. In addition, cerebral infarct volume and neurological function were evaluated at 7 days after IS.

Results

TH attenuates IS together with enhanced IRF4 expression as well as reduced production of pro-inflammatory cytokines. In addition, TH increased M2 macrophage polarization while inhibited M1 macrophage polarization. However, IRF4 knockout worsens neurological outcomes of stoke mice. The expression of pro-inflammatory cytokines were markedly increased in IRF4^−/- mice as compared with IRF4^+/+ mice at 8 h after stroke. Moreover, IRF4 knockout driven the macrophage polarization toward M1phenotype at 8 h after stroke. Most importantly, IRF4 knockout abolished the neuroprotective and anti-inflammatory effects of TH in IS.

Conclusion

Together, we report for the first time that TH attenuates neuroinflammation following IS by modulating M1/M2 macrophage polarization through the upregulation of IRF4 expression.

Study Protocol for a Randomized, Double-Blind, Placebo-Controlled, Phase-II Trial: AdrenoMedullin for Ischemic Stroke Study

OBJECTIVES

Adrenomedullin (AM), a vasoactive peptide, has strong anti-inflammatory and angiogenic properties, which have been reported to ameliorate the consequences of ischemic stroke in several animal models. After a phase I study in healthy volunteers, two phase II trials of AM for inflammatory bowel diseases have been recently completed. The current AdrenoMedullin For Ischemic Stroke (AMFIS) study aims to assess the safety and efficacy of AM in patients with acute ischemic stroke.

MATERIALS AND METHODS

The AMFIS study is an investigator-initiated, randomized, double-blind, phase-II trial. AM or placebo will be administered to patients with non-cardioembolic ischemic stroke within 24 h after stroke onset. In the first cohort of the AMFIS study, patients will be randomly allocated to the investigation treatment A (30 μg/kg of AM in total for 7 days, n = 20) or placebo group (n = 10). In the second cohort, patients will be assigned to the investigation treatment B (56 μg/kg of AM in total for 7 days, n = 20) or placebo group (n = 10).

RESULTS

Serious adverse events related to the protocol treatment will be evaluated as the primary outcome. All adverse events will be analyzed as the secondary outcome. Regarding efficacy endpoints, the change in National Institutes of Health Stroke Scale and modified Rankin Scale scores will be compared between investigation treatment and placebo groups.

CONCLUSIONS

AM is expected to be a safe and effective treatment for ischemic stroke.

Sivelestat-loaded nanostructured lipid carriers modulate oxidative and inflammatory stress in human dental pulp and mesenchymal stem cells subjected to oxygen-glucose deprivation

Stroke remains the leading cause of morbidity and mortality. Stem cell-based therapy offers promising hope for survivors and their families. Despite the clinical translation of stem cell-based therapies in stroke patients for almost two decades, results of these randomized controlled trials are not very optimistic. In these lines, an amalgamation of nanocarriers based drug delivery with stem cells holds great promise in enhancing stroke recovery. In the present study, we treated oxygen-glucose deprivation (OGD) exposed dental pulp stem cells (DPSCs) and mesenchymal stem cells (MSCs) with sivelestat-loaded nanostructured lipid carriers (NLCs). Various physicochemical limitations associated with sivelestat drug applications and its recent inefficacy in the clinical trials necessitates the development of novel delivery approaches for sivelestat. Therefore, to improve its efficacy on the survival of DPSCs and MSCs cell types under OGD insult, the current NLCs were formulated and characterized. Resulting NLCs exhibited a hydrodynamic diameter of 160-180 nm by DLS technique and possessed good PDI values of 0.2-0.3. Their shape, size and surface morphology were corroborated with microscopic techniques like TEM, SEM, and AFM. FTIR and UV-Vis techniques confirmed nanocarrier's loading capacity, encapsulation efficiency of sivelestat, and drug release profile. Oxidative stress in DPSCs and MSCs was assessed by DHE and DCFDA staining, and cell viability was assessed by Trypan blue exclusion test and MTT assay. Results indicated that sivelestat-loaded NLCs protected the loss of cell membrane integrity and restored cell morphology. Furthermore, NLCs successfully defended human DPSCs and MSCs against OGD-induced oxidative and inflammatory stress. In conclusion, modulation of oxidative and inflammatory stress by treatment with sivelestat-loaded NLCs in DPSCs and MSCs provides a novel strategy to rescue stem cells during ischemic stroke.

The Role of C-Reactive Protein and Fibrinogen in the Development of Intracerebral Hemorrhage: A Mendelian Randomization Study in European Population

Background: The causal association of C-reactive protein (CRP) and fibrinogen on intracerebral hemorrhage (ICH) remains uncertain. We investigated the causal associations of CRP and fibrinogen with ICH using two-sample Mendelian randomization. Method: We used single-nucleotide polymorphisms associated with CRP and fibrinogen as instrumental variables. The summary data on ICH were obtained from the International Stroke Genetics Consortium (1,545 cases and 1,481 controls). Two-sample Mendelian randomization estimates were performed to assess with inverse-variance weighted and sensitive analyses methods including the weighted median, the penalized weighted median, pleiotropy residual sum and outlier (MR-PRESSO) approaches. MR-Egger regression was used to explore the pleiotropy. Results: The MR analyses indicated that genetically predicted CRP concentration was not associated with ICH, with an odds ratio (OR) of 1.263 (95% CI = 0.935-1.704, p = 0.127). Besides, genetically predicted fibrinogen concentration was not associated with an increased risk of ICH, with an OR of 0.879 (95% CI = 0.060-18.281; p = 0.933). No evidence of pleiotropic bias was detected by MR-Egger. The findings were overall robust in sensitivity analyses. Conclusions: Our findings did not support that CRP and fibrinogen are causally associated with the risk of ICH.

Integration of ultra-high-pressure liquid chromatography-tandem mass spectrometry with machine learning for identifying fatty acid metabolite biomarkers of ischemic stroke

We report for the first time the integration of ultra-high-pressure liquid chromatography-tandem mass spectrometry with machine learning for identifying fatty acid metabolite biomarkers of ischemic stroke. In particular, we develop an optimal model to discriminate ischemic stroke patients from healthy persons with 100% sensitivity and 93.18% specificity. This research may facilitate understanding the roles of fatty acid metabolites in stroke occurrence, holding great potential in clinical stroke diagnosis.

Attenuation of the Induction of TLRs 2 and 4 Mitigates Inflammation and Promotes Neurological Recovery After Focal Cerebral Ischemia

The intense inflammatory response triggered in the brain after focal cerebral ischemia is detrimental. Recently, we showed that the suppression of toll-like receptors (TLRs) 2 and 4 attenuates infarct size and reduces the expression of pro-inflammatory cytokines in the ischemic brain. In this study, we further examined the effect of unsuppressed induction of TLRs 2 and 4 on the expression of its downstream signaling molecules and pro-inflammatory cytokines 1 week after reperfusion. The primary purpose of this study was to investigate the effect of simultaneous knockdown of TLRs 2 and 4 on M1/M2 microglial polarization dynamics and post-stroke neurological deficits and the recovery. Transient focal cerebral ischemia was induced in young adult male Sprague-Dawley rats by the middle cerebral artery occlusion (MCAO) procedure using a monofilament suture. Appropriate cohorts of rats were treated with a nanoparticle formulation of TLR2shRNA and TLR4shRNA (T2sh+T4sh) expressing plasmids (1 mg/kg each of T2sh and T4sh) or scrambled sequence inserted vector (vehicle control) expressing plasmids (2 mg/kg) intravenously via tail vein immediately after reperfusion. Animals from various cohorts were euthanized during reperfusion, and the ischemic brain tissue was isolated and utilized for PCR followed by agarose gel electrophoresis, real-time PCR, immunoblot, and immunofluorescence analysis. Appropriate groups were subjected to a battery of standard neurological tests at regular intervals until 14 days after reperfusion. The increased expression of both TLRs 2 and 4 and their downstream signaling molecules including the pro-inflammatory cytokines was observed even at 1-week after reperfusion. T2sh+T4sh treatment immediately after reperfusion attenuated the post-ischemic inflammation, preserved the motor function, and promoted recovery of the sensory and motor functions. We conclude that the post-ischemic induction of TLRs 2 and 4 persists for at least 7 days after reperfusion, contributes to the severity of acute inflammation, and impedes neurological recovery. Unlike previous studies in TLRs 2 or 4 knockout models, results of this study in a pharmacologically relevant preclinical rodent stroke model have translational significance.

Acute Treatment With Fingolimod Does Not Confer Long-Term Benefit in a Mouse Model of Intracerebral Haemorrhage

Intracerebral haemorrhage (ICH) has no specific treatment, but accounts for up to 15% of all strokes and has the highest mortality. Fingolimod (FTY720) is an immunomodulator approved for the management of multiple sclerosis, with abundant evidence of efficacy in experimental ischemic stroke, and more limited evidence in experimental ICH. The goal of this study was to confirm the efficacy of fingolimod in experimental ICH using rigorous and statistically well-powered studies. ICH was induced in C57BL/6JOlaHsd male and female mice by intrastriatal bacterial collagenase injection. Fingolimod (0.5 mg/kg) or saline was administered intraperitoneally after 0.5, 24 and 72 h, in a randomized and blinded manner. Functional improvement with cylinder, wire hanging, and foot fault tests was evaluated one and two weeks later. Lesion volume and hemispheric atrophy were quantified at the 14-day endpoint. There was a higher mortality in saline-treated females compared to fingolimod-treated females and saline-treated males. There was no treatment- or gender-related difference in the behavioural tests. Histological outcome measures did not differ between any of the groups. These results, contrasting with those of previous studies of fingolimod in experimental ICH, emphasize the importance of rigorous testing of this agent in models more representative of the clinical situation.

The role of neutrophils in mediating stroke injury in the diabetic db/db mouse brain following hypoxia-ischemia

Diabetic mice exhibit increased mortality and morbidity following stroke. Recent studies from our laboratory have indicated that increased morbidity in diabetic db/db mice relative to their non-diabetic db/+ littermates is associated with increased levels of MMP-9 protease activity, increased blood-brain barrier (BBB) permeability, and greater neutrophil infiltration following hypoxic/ischemic (H/I) insult. Neutrophils are a major source of proteases and reactive oxygen species and studies have reported neutrophil depletion/inhibition is protective in certain models of experimental stroke. The objective of the current study is to determine the role of neutrophils in the increased morbidity seen in db/db mice following acute ischemic stroke. In this study, we found a significant increase in circulating neutrophils in the db/db mice at 4 h post H/I, which bound to endothelial cells in the ipsilateral hemisphere and infiltrated into brain tissue by 24 h of recovery. Depletion of circulating neutrophils resulted in reduced neutrophil concentrations in blood and in the ipsilateral hemispheres of the brain of both db/+ and db/db mice and decreased the levels of MMP-9 within the infarcted area. This resulted in smaller infarct size in the db/db mice compared to non-treated controls but did not affect stroke outcome in db/+ mice. While there was a significant correlation between neutrophil number and the levels of MMP-9 in the ipsilateral hemisphere of control and diabetic mice, surprisingly, neutrophil depletion had no effect on BBB permeability in either group. Thus, the current study suggests that neutrophil depletion reduces MMP-9 protease levels and improves stroke outcome in db/db mice but not in their db/+ counterparts.