Cerebral Ischemia Research Articles

Comparison of the protective effects of silymarin and thymoquinone in the focal cerebral ischemia–reperfusion rat model

ABSTRACT Silymarin and thymoquinone exert neuroprotective effects, although their combined effects in focal cerebral ischemia/reperfusion (I/R) models are unknown. We compared the effect of silymarin and thymoquinone in an I/R rat model. Wistar rats were divided into five groups: SHAM, REP (I/R), SIR (200 mg/kg silymarin+I/R), TIR (3 mg/kg thymoquinone+I/R), and STIR (200 mg/kg silymarin+3-mg thymoquinone+I/R). The rats underwent bilateral carotid artery occlusion for 30 min and neurological assessments 24 h thereafter. Apoptosis was evaluated using anti-caspase-3 and terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) assays. Astrocyte activation was determined using an anti-GFAP antibody. Total antioxidant status (TAS), total oxidant status (TOS), and trimethylamine N-oxide (TMAO) levels were measured. SHAM and REP rats had the lowest and highest neurological scores, respectively (p = 0.001). REP rats showed greater deterioration than SIR, TIR, and STIR rats. SIR, TIR, and STIR rats had fewer TUNEL and caspase-3-positive cells than REP rats (p<0.05). GFAP expression was higher in REP rats (p<0.05) than in SIR, TIR, and STIR rats (p<0.05). SIR and TIR rats showed higher TAS than REP rats (p<0.05). SIR, TIR, and STIR rats had lower TMAO values than REP and SHAM rats (p<0.05). Silymarin/thymoquinone reduces impairment, apoptosis, and astrocyte activation. Combination therapy reduces TMAO levels.

Identifying the quality markers and optimizing the processing of Gastrodiae rhizoma to treat brain diseases

BackgroundGastrodiae rhizoma (GR) refers to the dried tuber of Gastrodia elata Bl. and has been used for many centuries to treat brain diseases, such as Alzheimer’s disease, major depressive disorder, and cerebral ischemia. However, the processing of GR is complex and varied, resulting in unstable clinical treatment effects. The processing protocols significantly affect the active ingredients and curative effects of GR. We can optimize the processing of GR by identifying quality markers to treat brain diseases.MethodsFresh tubers of G. elata Bl. were processed under eight different protocols, and their resulting contents of potentially bioactive compounds were compared using liquid chromatography mass spectrometry to screen the potential quality markers of GR through stoichiometric analysis. The potential quality markers of GR targeting Alzheimer’s disease, major depressive disorder, and cerebral ischemia were identified by network pharmacology, and the potentially neuroprotective effects of these components were validated through simulated docking to likely protein targets. Finally, a fit degree analysis was carried out using different composition ratios and proportions of the disease component degree value, and the therapeutic effects of different processing methods on Alzheimer’s disease, major depressive disorder, and cerebral ischemia were outlined clearly.ResultsWe identified 32 potential therapeutic components and screened 13 quality markers in GR, of which five quality markers (galactinol, glucosyringic acid, parishins C and E, and S-(4-hydroxybenzyl)-glutathione) showed efficacy against all three brain diseases. Furthermore, steaming and microwave-drying during processing can optimize the components of these quality markers for treating the three diseases.ConclusionProcessing protocols significantly affect the therapeutic components of GR and may also impact its effectiveness in treating brain diseases. Accordingly, optimizing the processing methods of GR to correspond to different therapeutic purposes may improve its efficacy against brain diseases.

Molecular Imaging Reveals Antineuroinflammatory Effects of HDAC6 Inhibition in Stroke Models.

Ischemic stroke is a devastating disease that causes neuronal death, neuroinflammation, and other cerebral damage. However, effective therapeutic strategies for ischemic stroke are still lacking. Histone deacetylase 6 (HDAC6) has been implicated in the pathogenesis of ischemic stroke, and the pharmacological inhibition of HDAC6 has shown promising neuroprotective effects. In this study, we utilized positron emission tomography (PET) imaging with the HDAC6-specific radioligand [18F]PB118 to investigate the dynamic changes of HDAC6 expression in the brain after ischemic injury. The results revealed a significant decline in [18F]PB118 uptake in the ipsilateral hemisphere on the first day after ischemia, followed by a gradual increase on days 4 and 7. To evaluate the therapeutic potential of HDAC6 inhibitors, we developed a novel brain-permeable and potent HDAC6 inhibitor, PB131, and assessed its neuroprotective effects in an ischemic stroke mouse model. PET imaging studies demonstrated that PB131 treatment alleviated the decline in [18F]PB118 uptake and reduced the infarct size in middle cerebral artery occlusion mice. Furthermore, PET imaging with the TSPO-specific radioligand [18F]FEPPA revealed that PB131 significantly suppressed neuroinflammation in the ischemic brain. These findings provide insights into the dynamic changes of HDAC6 in ischemic stroke and the potential of HDAC6 inhibitors as novel therapeutic agents for this condition.

A temperature-ultrasound sensitive nanoparticle delivery system for exploring central neuroinflammation mechanism in stroke-heart syndrome.

Cardiovascular events secondary to stroke-collectively classified as stroke-heart syndrome-greatly impair the patient's prognosis, however its underlying mechanism has yet to be determined. To investigate the mechanism of central neuroinflammation and its effects on stroke-heart syndrome, a temperature-ultrasound responsive brain-targeted drug delivery system, DATS/MION-LPE, was synthesized to specifically study neuroinflammation in the mouse middle cerebral artery occlusion (MCAO) model. The specific polymer of DATS/MION-LPE can close the nanoparticle pores at 37°C, restricting drug release in the circulation. After the nanoparticles were targeted to brains, the polymer can be cleaved under external ultrasound irradiation, reopening the nanoparticle pores and allowing drug release, therefore directly managing the neuroinflammation. After a stroke, a significant cerebral inflammation occurred, with elevated IL-1β and pyrin domain-containing 3 (NLRP3) inflammasome. Accordingly, significantly increased histone deacetylase 6 (HDAC6) and decreased sirtuin 1 (SIRT1) were observed. An antagonistic relationship between HDAC6 and SIRT1 was found, which can jointly regulate the cerebral NLRP3 expression. The systemic IL-1β and ATP levels were increased after the stroke, accompanied by a significant heart injury including contractile dysfunction, elevated IL-1β levels, and oxidative stress. Meanwhile, neuroinflammation can trigger sympathetic nervous overexcitation with associated heart damage. DATS/MION-LPE can targetedly effect on ischemic brain, exhibiting cerebral and cardiac protective effects including downregulated cerebral NLRP3 and HDAC6 expressions, upregulated SIRT1 expressions in brain, reduced IL-1β and ATP in circulation, and alleviated cardiac impairment. This study introduced the key role of neuroinflammation in stroke-heart syndrome and first investigated the crucial HDAC6/SIRT1-NLRP3 circuit in this process. Heart injury secondary to stroke is mediated by neuroinflammation induced systemic inflammatory responses and sympathoexcitation. DATS/MION-LPE is a unique tool and effective therapeutic agent, which provides new insights into combinational heart and cardiac protection.

Muscle structure assessment using synchrotron radiation X-ray micro-computed tomography in murine with cerebral ischemia.

Muscles are crucial for balance and walking, activities which depend specifically on the lower extremity muscles. Therefore, the evaluation of stroke induced atrophy and paralysis is essential; however, determining the extent of damage in the days after its occurrence remains challenging. In this study, we evaluated ischemic stroke-induced soleus muscle damage in gerbils using synchrotron radiation X-ray micro-computed tomography (SR-µCT), comparing a control group (n = 3), animals 7 days after stroke (7 d, n = 3), and animals 14 days after stroke (14 d, n = 3). The left muscle was paralyzed, whereas the right muscle was not. Subsequently, we quantified the assessment by segmenting the soleus muscle based on the extracellular space/matrix and fiber region to determine the degree of damage. The muscle fiber-to-extracellular space/matrix ratio were significantly damaged due to paralysis on the left side (control vs. 14 d, P = 0.040). Muscle area was significantly different at 14 d between the left and right sides (P = 0.010). Additionally, the left local fascicle surface area, thickness, global pennation angle, and local fascicle angle were significantly different between the control and 14 d groups (P = 0.002, P = 0.007, P = 0.005, and P = 0.014 respectively). These findings underscore the potential of post-stroke animal studies in improving rehabilitation treatment for the central nervous system by assessing the degree of muscle recovery.

Electroacupuncture alleviated post-stroke cognitive impairment via the mTOR/NLRP3-mediated autophagy-inflammatory pathway

BackgroundPost-stroke cognitive impairment (PSCI) severely reduces quality of life of patients with stroke. This study aimed to assess the effects of electroacupuncture (EA) on PSCI and the role of the mTOR/NLRP3-mediated autophagy-inflammatory pathway in this process.MethodsThe rat focal cerebral ischemia model was established using middle cerebral artery occlusion (MCAO). Following successful induction of the model, EA was applied to the bilateral Fengchi, Fengfu, and Dazhui acupoints, and brain tissue samples were collected on day 15. Cognitive function was assessed using the Morris water maze test. Cerebral infarct volume was quantified by Triphenyltetrazolium chloride (TTC) staining. Hematoxylin–eosin and TUNEL staining were performed to evaluate pathological changes and apoptosis rates. Apoptosis-, inflammation-, and autophagy-related biomarkers were measured, and autophagosomes were visualized using transmission electron microscopy.ResultsMCAO rats exhibited slower weight gain, reduced mobility, increased infarct size, pathological damage, and apoptosis, confirming successful establishment of the MCAO rat model. Following EA treatment, MCAO rats displayed faster weight gain, improved mobility, and shorter escape latency. EA also reduced the area of cerebral infarction and alleviated pathological damage and apoptosis in MCAO rats. Furthermore, EA downregulated IL-1β, IL-18, NLRP3, and LC3 II/LC3 I expression and upregulated p62, mTOR, and Beclin-1 expression in MCAO rats. EA treatment also decreased the number of autophagosomes in these rats.ConclusionsEA effectively mitigates post-stroke cognitive impairment by reducing apoptosis, inflammation, and autophagy through the regulation of the mTOR/NLRP3-mediated autophagy-inflammatory pathway, offering valuable therapeutic insights for stroke rehabilitation.

Efficacy of Omega-5 NanoPSO Treatment in the Hippocampus, Through Antioxidant Mechanisms, After an Ischemia/Reperfusion Injury, in Murine Model

Stroke is the third cause of death worldwide and a health problem, and current therapy continues to be very poor. It promotes an alteration associated with excitotoxicity, oxidative stress, and inflammatory processes, exacerbating the damage in the brain. Although cortical areas are the most affected by stroke, the hippocampus can be impacted in the long term through the pathways it connects with these areas, which are associated further with motor alterations; this encourages the search for new therapeutic approaches. Omega-5, being an antioxidant, participates in regulating oxidative stress. A recently designed nanoemulsified compound coupled with pomegranate seed oil (NanoPSO) maintains bioavailability in the body for longer. Omega-5 NanoPSO is more effective in different models of neurodegenerative diseases and metabolic disorders. Therefore, it is important to analyze the effect of omega-5 NanoPSO on ischemic damage through changes in the hippocampus, oxidative mechanisms, and behavioral outcomes. Male Wistar rats were used in five groups; three groups were subjected to an ischemic event through bilateral occlusion of the carotid arteries. An ischemia group received omega-5 NanoPSO after injury, and another group received omega-5 NanoPSO performed two weeks before the ischemic event and three weeks after the surgical process. The control and sham groups did not show changes in the hippocampus and behavior. In the ischemia group, neuronal loss, oxidative stress, and a higher expression of astrocytes were maintained in the hippocampal region, and behavior was modified. In the post and pre-treatment group with omega-5 NanoPSO, we observed reduced damage, glial proliferation, and oxidative stress. It increased neuron survival in the hippocampal region and improved the locomotion. These results highlight its promise for use in clinical settings to treat patients suffering from ischemic brain injury.

Mechanisms of fibrinogen trans-activation of the EGFR/Ca2+ signaling axis to regulate mitochondrial transport and energy transfer and inhibit axonal regeneration following cerebral ischemia.

Ischemic stroke results in inhibition of axonal regeneration but the roles of fibrinogen (Fg) in neuronal signaling and energy crises in experimental stroke are under-investigated. We explored the mechanism of Fg modulation of axonal regeneration and neuronal energy crisis after cerebral ischemia using a permanent middle cerebral artery occlusion (MCAO) rat model and primary cortical neurons under low glucose-low oxygen. Behavioral tests assessed neurological deficits; immunofluorescence, immunohistochemistry, and Western-blot analyzed Fg and protein levels. Fluo-3/AM fluorescence measured free Ca2+ and ATP levels were gauged via specific assays and F560nm/F510nm ratio calculations. Mito-Tracker Green labeled mitochondria and immunoprecipitation studied protein interactions. Our comprehensive study revealed that Fg inhibited axonal regeneration post-MCAO as indicated by reduced GAP43 expression along with elevated free Ca2+, both suggesting an energy crisis. Fg impeded mitochondrial function and mediated impairment through the EGFR/Ca2+ axis by trans-activating EGFR via integrin αvβ3 interaction. These results indicate that the binding of Fg with integrin αvβ3 leads to the trans-activation of the EGFR/Ca2+ signaling axis thereby disrupting mitochondrial energy transport and axonal regeneration and exacerbating the detrimental effects of ischemic neuronal injury.

LncRNA Taurine Up-Regulated 1 Knockout Provides Neuroprotection in Ischemic Stroke Rats by Inhibiting Nuclear-Cytoplasmic Shuttling of HuR

Background: Long non-coding RNA taurine-upregulated gene 1 (TUG1) is involved in various cellular processes, but its role in cerebral ischemia–reperfusion injury remains unclear. This study investigated TUG1’s role in regulating the nucleocytoplasmic shuttling of human antigen R (HuR), a key apoptosis regulator under ischemic conditions. Methods: CRISPR-Cas9 technology was used to generate TUG1 knockout Sprague Dawley rats to assess TUG1’s impact on ischemic injury. The infarct area and neuronal apoptosis were evaluated using TUNEL, hematoxylin and eosin (HE), and TTC staining, while behavioral functions were assessed. Immunofluorescence staining with confocal microscopy was employed to examine TUG1-mediated HuR translocation and expression changes in the apoptosis-related proteins COX-2 and Bax. Results: TUG1 knockout rats showed significantly reduced cerebral infarct areas, decreased neuronal apoptosis, and improved neurological functions compared to controls. Immunofluorescence staining revealed that HuR translocation from the nucleus to the cytoplasm was inhibited, leading to decreased COX-2 and Bax expression levels. Conclusions: TUG1 knockout reduces ischemic damage and neuronal apoptosis by inhibiting HuR nucleocytoplasmic shuttling, making TUG1 a potential therapeutic target for ischemic stroke.

Intravenous Regeneration-associated Cell Transplantation Enhances Tissue Recovery in Mice with Acute Ischemic Stroke.

Previously, we reported that transplantation of regeneration-associated cells (RACs) via the ipsilateral external carotid artery reduced stroke volume in mice with permanent occlusion of the middle cerebral artery (MCA). However, intracarotid arterial transplantation is invasive and requires skill, and severe complications may occur, such as thromboembolism, infection, and decreased cerebral blood flow. This study aimed to investigate the efficacy of intravenous injection of RACs in reducing stroke volume and increasing anti-inflammatory and angiogenic factors in mice with focal cerebral ischemia. Mice with occluded MCAs received intravenous injections of phosphate-buffered saline (PBS) (control), low-dose RACs, or high-dose RACs. The proximal part of the left MCA was occluded to induce permanent focal ischemia. After 3 days, we administered PBS or low-dose (1 × 104 /50 µL) or high-dose RACs (1 × 105 /50 µL) through the tail vein and assessed the infarct volume on day 7. High-dose RACs significantly decreased infarct volume compared to PBS, whereas low-dose RACs showed no effect. The number of interleukin-10 (IL-10)-positive and vascular endothelial growth factor (VEGF)-positive cells in the peri-infarct area on day 7 was significantly higher in mice treated with low-dose and high-dose RACs than in the PBS control group. Intravenous injection of RACs can reduce ischemic stroke volume; however, a higher dose of RACs is required than the dose used in intraarterial transplantation. By assessing IL-10 and VEGF expression, the study sheds light on the underlying mechanisms of RAC therapy, revealing its potential anti-inflammatory and angiogenic properties in the treatment of cerebral ischemia.

Fecal microbiota transplantation alleviates neuronal Apoptosis, necroptosis and M1 polarization of microglia after ischemic stroke

ObjectiveThis study aims to delve into the mechanisms underlying the improvement of neurological function in rats with ischemic stroke through fecal microbiota transplantation.Methods: A total of fifty male Sprague-Dawley rats were categorized into three groups: sham surgery, model, and fecal transplantation. We assessed behavioral and pathological alterations in the rats using modified neurological function scoring and TTC staining. Additionally, Western blot and immunofluorescence techniques were employed to examine the expression levels of RIP1, RIP3, MLKL, p-MLKL, Bcl-2, Bax, and cleaved caspase-3 in neurons of ischemic brain tissue, while iNOS and Arg1 were analyzed to evaluate microglial polarization.Results: The fecal transplantation group exhibited a decline in neurological function score compared to the model group, accompanied by a reduction in infarct volume (P < 0.05). Relative to the sham surgery group, the model group displayed a significant increase in the expression levels of necroptosis-related proteins RIP1, RIP3, p-MLKL, apoptotic proteins Bax and cleaved caspase-3, and the M1 microglial cell marker iNOS in ischemic brain tissue, while Bcl-2 expression was notably decreased (P < 0.05). Conversely, compared to the model group, the fecal transplantation group demonstrated decreased expression levels of RIP1, RIP3, p-MLKL, Bax, cleaved caspase-3, and iNOS, along with increased expression of Bcl-2.Conclusion: Fecal microbiota transplantation presents a promising avenue for enhancing neurological function in rats with ischemic stroke by inhibiting neuronal apoptosis, necroptosis, and M1 polarization of microglial cells.

Multimodal action of phosphodiesterase 5 inhibitors against neurodegenerative disorders: An update review.

Phosphodiesterase type 5 (PDE5) is an enzyme primarily found in the smooth muscle of the corpus cavernosum and also highly expressed in the substantia nigra, cerebellum, caudate, hippocampal regions and cerebellar purkinje cells, responsible for selectively breaking down cyclic guanosine monophosphate (cGMP) into 5'-GMP and regulate intracellular cGMP levels. As a second messenger, cyclic GMP enhances signals at postsynaptic receptors and triggers downstream effector molecules, leading to changes in gene expression and neuronal responses. Additionally, cGMP signaling transduction cascade, present in the brain, is also essential for learning and memory processes. Mechanistically, PDE5 inhibitors share structural similarities with cGMP, competitively binding to PDE5 and inhibiting cGMP hydrolysis. This action enhances the effects of nitric oxide, resulting in anti-inflammatory and neuroprotective effects. Neurodegenerative disorders entail the progressive loss of neuron structure, culminating in neuronal cell death, with currently available drugs providing only limited symptomatic relief, rendering neurodegeneration considered incurable. PDE5 inhibitors have recently emerged as a potential therapeutic approach for neurodegeneration, neuroinflammation, and diseases involving cognitive impairment. This review elucidates the principal roles of 3',5'-cyclic adenosine monophosphate (cAMP) and cGMP signaling pathways in neuronal functions, believed to play pivotal roles in the pathogenesis of various neurodegenerative disorders. It provides an updated assessment of PDE5 inhibitors as disease-modifying agents for conditions such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, cerebral ischemia, Huntington's disease, and neuroinflammation. The paper aims to review the current understanding of PDE5 inhibitors, which concurrently regulate both cAMP and cGMP signaling pathways, positing that they may exert complementary and synergistic effects in modifying neurodegeneration, thus presenting a novel direction in therapeutic discovery. Moreover, the review provides critical about biological functions, therapeutic potentials, limitations, challenges, and emerging applications of selective PDE5 inhibitors. This comprehensive overview aims to guide future academic and industrial endeavors in this field.

Shh regulates M2 microglial polarization and fibrotic scar formation after ischemic stroke

BackgroundFibrotic scar formation is a critical pathological change impacting tissue reconstruction and functional recovery after ischemic stroke. The regulatory mechanisms behind fibrotic scarring in the central nervous system (CNS) remain largely unknown. While macrophages are known to play a role in fibrotic scar formation in peripheral tissues, the involvement of microglia, the resident immune cells of the CNS, in CNS fibrosis requires further exploration. The Sonic Hedgehog (Shh) signaling pathway, pivotal in embryonic development and tissue regeneration, is also crucial in modulating fibrosis in peripheral tissues. However, the impact and regulatory mechanisms of Shh on fibrotic scar formation post-ischemic stroke have not been thoroughly investigated. MethodsThis study explores whether Shh can regulate fibrotic scar formation post-ischemic stroke and its underlying mechanisms through in vivo and in vitro manipulation of Shh expression. ResultsOur results showed that Shh expression was upregulated in the serum of acute ischemic stroke patients, as well as in the serum, CSF, and ischemic regions of MCAO/R mice. Moreover, the upregulation of Shh expression was positively correlated with fibrotic scar formation and M2 microglial polarization. Shh knockdown inhibited fibrotic scar formation and M2 microglial polarization while aggravating neurological deficits in MCAO/R mice. In vitro, adenoviral knockdown or Smoothened Agonist (SAG) activation of Shh expression in BV2 cells following OGD/R regulated their polarization and influenced the expression of TGFβ1 and PDGFA, subsequently affecting fibroblast activation. ConclusionThese results suggest that Shh regulates M2 microglial polarization and fibrotic scar formation after cerebral ischemia.

Basal Ganglia’s influence on awake testing in carotid endarterectomy

BackgroundWhite matter changes (WMC) have been associated with the underlying presence of chronic cerebral ischemia, such as in carotid stenosis and age-related white matter changes (ARWMC). A low attenuation on computed tomography (CT) characterizes these alterations. Patients undergoing carotid endarterectomy (CEA) with severe WMC may be at increased risk of intraoperative neurologic deficits (IND) during carotid clamping. This study aims to determine the potential role of ARWMC as a predictor of IND during CEA with regional anesthesia (RA). MethodsPatients undergoing CEA under RA at a tertiary referral center, who presented with IND during CEA were prospectively and consecutively recruited between January 2011 and December 2023. The control group comprised the immediately consecutive patient who underwent the same procedure without IND. From this sample, patients with preoperative CT were selected and compared based on ARWMC score (≤ 1 and 2). Differences in demographics and comorbidities were assessed between the groups. A multivariable logistic regression was performed. ResultsOne hundred and twenty-one patients were enrolled. Patients with IND had a significantly higher ARWMC score in basal ganglia (ARWMC-BG ≥ 2) and posterior circulation disease was more frequent (27.8 %). No significant differences were observed in anatomical variations of the circle of Willis.For patients with ARWMC-BG ≥ 2, a significant burden of other comorbidities was associated, such as chronic kidney disease, coronary disease, and atrial fibrillation. After multivariable logistic regression analysis, ARWMC-BG score ≥ 2 was an independent risk factor for IND (aOR 3.472). ConclusionAn ARWMC-BG score above 2 predicts positive intraoperative “awake tests” in CEA with RA, constituting a reliable tool to stratify patients according to their risk of adverse events. However, larger prospective cohorts are needed to validate these findings and offer a better selection and management of this subset of patients.

MRPL41, as a target for acupuncture, promotes neuron apoptosis in models of ischemic stroke via activating p53 pathway

Neuronal death is the key cause of ischemic stroke. Acupuncture (Acu) is a recognized method for the treatment and amelioration of cerebral ischemia. However, the molecular mechanism of Acu for treating ischemic stroke has not yet been detailedly elucidated. Based our microarray analysis results, mitochondrial ribosomal protein L41 (MRPL41), which is related to apoptosis, was identified as the target of Acu. MRPL41 expression was increased in middle cerebral artery occlusion/reperfusion (MCAO/R) model and reduced after Acu treatment. Following, MCAO/R model and oxygen and glucose deprivation/reoxygenation (OGD/R) model were established to explore the effect of MRPL41. Knockdown of MRPL41 increased cell viability and ani-apoptotic protein (Bcl-2) expression, and reduced apoptosis intensity and pro-apoptotic protein (Bax and Cleaved caspase-3) of OGD/R neurons. In vivo, MRPL41 silencing decreased neurological severity score, shrank infarct area, reduced encephaledema and neuron apoptosis. In addition, reduction of MRPL41 caused loss of p53. Our data uncover that Acu targets MRPL41, following with inhibiting neuron apoptosis via p53 pathway, thereby ameliorating ischemic stroke.

Neovascularization as a Leading Mechanism of Intraplaque Hemorrhage and Carotid Plaque Destabilization: A Narrative Review.

Intraplaque neovascularization (IPN) is considered a leading mechanism causing carotid plaque destabilization. We provide an objective and comprehensive summary of the biology, imaging techniques, and treatment options related to carotid IPN. Plaque neovascularization has been reported to originate mainly from the adventitial vasa vasorum as a response to hypoxia. The leakage and rupture of neovessels lead to the formation of extravasations and foci of inflammation that destabilize the plaque. Vascular endothelial growth factor and its receptors are key regulators of neoangiogenesis. Neovascularization can be analyzed by advanced computed tomography and magnetic resonance imaging. The basic tools for the ultrasound assessment of IPN are contrast-enhanced ultrasound, superb microvascular imaging, and ultrasound molecular imaging. A promising direction of research seems to be the identification of patients with advanced plaque neovascularization. A simple test assessing low-velocity flow in the IPN can detect patients at risk of stroke before they experience rupture of defective neovessels and intracerebral embolism. In addition to surgical treatment, the stabilization of carotid atherosclerotic plaque can be supported pharmacologically. Statins have the best-documented role in this respect. The ideal moment of intensified therapeutic intervention in patients with previously stable carotid plaque is its increased neovascularization. However, the time frame in which intracerebral embolization may occur is unknown, and therapeutic intervention may be too late. The formation of deficient neovessels can currently be non-invasively evaluated with ultrasound. Superb microvascular imaging may change the clinical approach for asymptomatic patients at risk of cerebral ischemia.

Cedrol attenuates acute ischemic injury through inhibition of microglia-associated neuroinflammation via ERβ-NF-κB signaling pathways

Microglia-associated neuroinflammation plays essential roles in pathology of acute stroke. Cedrol, a natural compound extracted from ginger, has been shown to confer inhibitory effects on inflammation in various diseases. However, whether Cedrol suppresses neuroinflammation and protects brains from acute ischemic injury still remains unclear. In this study, we found that Cedrol inhibited microglia activation and the production of inflammatory factors in LPS-challenged microglia and the penumbra region of middle cerebral artery occlusion (MCAO) mice. We also found that Cedrol reduced the infarct size and mNSS scores and improved acute cerebral ischemia-induced behavioral outcomes, suggesting remarked neuroprotection of Cedrol. Molecular docking analysis showed that Cedrol bound to estrogen receptor β (ERβ) with moderate-strong affinity. Intriguingly, treatment with fulvestrant, an ER blocker, abolished the anti-inflammatory effects of Cedrol. Cedrol significantly reversed the LPS- and MCAO-induced increases in phosphorylation levels of IκB and NF-κB P65 in primary microglia and MCAO mice, respectively. Additionally, Cedrol was observed to rescue LPS-induced shuttling of NF-κB P65 from cytoplasm to nuclei in primary microglia, indicating inhibitory effects of Cedrol on NF-κB signaling. These results suggest microglia associated neuroinflammation may be mediated by ERβ-NF-κB signaling pathway. Together, our study reveals that Cedrol protected brain function from acute cerebral ischemia through inhibition of microglia-associated neuroinflammation via ERβ-NF-κB signaling pathways, and Cedrol may serve as an alternative option for treatment of acute stroke injury.

Pharmacotherapy in SAH: Clinical Trial Lessons.

Subarachnoid Haemorrhage (SAH) is a medical emergency with potentially devastating outcomes. It is without doubt that over the past decades, there has been a radical change in the approach towards patients with SAH, both in terms of the surgical as well as of the pharmacological treatments offered. The present review aims to outline the principal data regarding the best practice in the pharmacotherapy of SAH, as well as to sum up the emerging evidence from the latest clinical trials. To date, nimodipine is the only evidence-based treatment of vasospasm. However, extensive research is currently underway to identify novel substances with magnesium sulphate, cilostazol, clazosentan and fasudil, demonstrating promising results. Antifibrinolytic therapy could help reduce mortality, and anticoagulants, in spite of their associated hazards, could actually reduce the incidence of delayed cerebral ischemia. The effectiveness of triple-H therapy has been challenged, yet evidence on the optimal regimen is still pending. Statins may benefit some patients by reducing the incidence of vasospasm and delayed ischemic events. As several clinical trials are underway, it is expected that in the years to come, more therapeutic options will be added to the attending physician's armamentarium.

2-Acetylacteoside improves recovery after ischemic stroke by promoting neurogenesis via the PI3K/Akt pathway

Ischemic stroke induces adult neurogenesis in the subventricular zone (SVZ), even in elderly patients. Harnessing of this neuroregenerative response presents the therapeutic potential for post-stroke recovery. We found that phenylethanoid glycosides (PhGs) derived from Cistanche deserticola aid neural repair after stroke by promoting neurogenesis. Among these, 2-acetylacteoside had the most potent on the proliferation of neural stem cells (NSCs) in vitro. Furthermore, 2-acetylacteoside was shown to alleviate neural dysfunction by increase neurogenesis both in vivo and in vitro. RNA-sequencing analysis highlighted differentially expressed genes within the PI3K/Akt signaling pathway. The candidate target Akt was validated as being regulated by 2-acetylacteoside, which, in turn, enhanced the proliferation and differentiation of cultured NSCs after oxygen-glucose deprivation/reoxygenation (OGD/R), as evidenced by western blot analysis. Subsequent analysis using cultured NSCs from adult subventricular zones (SVZ) confirmed that 2-acetylacteoside enhanced the expression of phosphorylated Akt (p-Akt), and its effect on NSC neurogenesis was shown to be dependent on the PI3K/Akt pathway. In summary, our findings elucidate for the first time the role of 2-acetylacteoside in enhancing neurological recovery, primarily by promoting neurogenesis via Akt activation following ischemic brain injury, which offers a novel strategy for long-term cerebrological recovery in ischemic stroke.

A mechanistic systems biology model of brain microvascular endothelial cell signaling reveals dynamic pathway-based therapeutic targets for brain ischemia

Ischemic stroke is a significant threat to human health. Currently, there is a lack of effective treatments for stroke, and progress in new neuron-centered drug target development is relatively slow. On the other hand, studies have demonstrated that brain microvascular endothelial cells (BMECs) are crucial components of the neurovascular unit and play pivotal roles in ischemic stroke progression. To better understand the complex multifaceted roles of BMECs in the regulation of ischemic stroke pathophysiology and facilitate BMEC-based drug target discovery, we utilized a transcriptomics-informed systems biology modeling approach and constructed a mechanism-based computational multipathway model to systematically investigate BMEC function and its modulatory potential. Extensive multilevel data regarding complex BMEC pathway signal transduction and biomarker expression under various pathophysiological conditions were used for quantitative model calibration and validation, and we generated dynamic BMEC phenotype maps in response to various stroke-related stimuli to identify potential determinants of BMEC fate under stress conditions. Through high-throughput model sensitivity analyses and virtual target perturbations in model-based single cells, our model predicted that targeting succinate could effectively reverse the detrimental cell phenotype of BMECs under oxygen and glucose deprivation/reoxygenation, a condition that mimics stroke pathogenesis, and we experimentally validated the utility of this new target in terms of regulating inflammatory factor production, free radical generation and tight junction protection in vitro and in vivo. Our work is the first that complementarily couples transcriptomic analysis with mechanistic systems-level pathway modeling in the study of BMEC function and endothelium-based therapeutic targets in ischemic stroke.