Metabolic Imaging of Acute Ischemic Stroke (PET, 1Hydrogen Spectroscopy, 17Oxygen Imaging, 23Sodium MRI, pH Imaging).

Acute stroke imaging plays a vital and time-sensitive role in therapeutic decision-making. Current clinical workflows widely use computed tomography (CT) and magnetic resonance (MR) techniques including CT and MR perfusion to estimate the volume of ischemic penumbra at risk for infarction without acute intervention. The use of imaging techniques aimed toward evaluating the metabolic derangements underlying a developing infarct may provide additional information for differentiating the penumbra from benign oligemia and infarct core. The authors review several modalities of metabolic imaging including PET, hydrogen and oxygen spectroscopy, sodium MRI, and pH-weighted MRI.

Edaravone dexborneol protects against cerebral ischemia/reperfusion-induced blood-brain barrier damage by inhibiting ferroptosis via activation of nrf-2/HO-1/GPX4 signaling.

PURPOSE: Ferroptosis has recently been recognized as a mechanism of cerebral ischemia-reperfusion (I/R) injury, attributed to blood-brain barrier (BBB) disruption. Edaravone dexboneol (Eda.B) is a novel neuroprotective agent widely employed in ischemic stroke, which is composed of edaravone (Eda) and dexborneol. This study aimed to investigate the protective effects of Eda.B on the BBB in cerebral I/R and explore its potential mechanisms. METHODS: Transient middle cerebral artery occlusion (tMCAO) Sprague-Dawley-rats model was used. Rats were randomly assigned to sham-operated group (sham, n = 20), model group (tMCAO, n = 20), Eda.B group (Eda.B, n = 20), Eda group (Eda, n = 20) and dexborneol group (dexborneol, n = 20), and Eda.B + Zinc protoporphyria group (Eda.B + ZnPP, n = 5). Infarct area, cellular apoptosis and neurofunctional recovery were accessed through TTC staining, TUNEL staining, and modified Garcia scoring system, respectively. BBB integrity was evaluated via Evans blue staining. Nuclear factor E2 related factor 2 (Nrf-2)/heme oxygenase 1 (HO-1)/glutathione peroxidase 4 (GPX4) signaling were qualified by Western blot. Transmission electron microscopy (TEM) revealed alterations in ipsilateral brain tissue among groups. Glutathione (GSH) and malondialdehyde (MDA) levels, and Fe2+ tissue content determination were detected. RESULTS: Eda.B effectively improved neurological deficits, diminished infarct area and cellular apoptosis, as well as ameliorated BBB integrity in tMCAO rats. Further, Eda.B significantly inhibited ferroptosis, as evidenced by ameliorated pathological features of mitochondria, down-regulated of MDA and Fe2+ levels and up-regulated GSH content. Mechanistically, Eda.B attenuated BBB disruption via Nrf-2-mediated ferroptosis, promoting nuclear translocation of Nrf-2, increasing HO-1, GPX4 expression, alleviating the loss of zonula occludens 1 (ZO-1) and occludin as well as decreasing 4-hydroxynonenal (4-HNE) level. CONCLUSIONS: This study revealed for the first time that Eda.B safeguarded the BBB from cerebral I/R injury by inhibiting ferroptosis through the activation of the Nrf-2/HO-1/GPX4 axis, providing a novel insight into the neuroprotective effect of Eda.B in cerebral I/R.

Acrobatic training prevents motor deficits and neuronal loss in male and female rats following chronic cerebral hypoperfusion.

BACKGROUND: Chronic cerebral hypoperfusion in vascular dementia leads to memory and motor deficits; Physical exercise improves these aspects and promotes neuroprotection. Sexual dimorphism may significantly influence both ischemic and exercise outcomes. AIMS: The aim of this study was to investigate the effects of 2VO (Two-Vessel occlusion) and the acrobatic training on motor function, functional performance, and tissue loss in male and female rats. METHODS: Male and female rats were randomly divided into 4 groups: sham acrobatic, sham sedentary, 2VO acrobatic and 2VO sedentary. After 45 days of 2VO surgery, the animals received 4 weeks of acrobatic training. At the end, open field, beam balance and horizontal ladder tests were performed. Brain samples were taken for histological and morphological evaluation. RESULTS: Spontaneous motor activity in the open field was not affected by 2VO, on the other hand, an impairment in forelimb placement was observed after 2VO and acrobatic training prevented errors and improved hindlimb placement. Neuronal loss was found in the motor cortex and striatum after 2VO, especially in females, which was prevented by acrobatic training. CONCLUSION: Mild motor damage was found in animals after 2VO when refined movement was evaluated, probably associated to neuronal death in the motor cortex and striatum. The acrobatic exercise showed a neuroprotective effect, promoting neuronal survival and attenuating the motor deficit.

Inhibition of Anaplastic Lymphoma Kinase Protects From Ischemic Stroke.

BACKGROUND: Ischemic stroke is often accompanied by oxidative stress and inflammatory response, both of which work synergistically to exacerbate the disruption of the blood-brain barrier and ischemic brain injury. ALK (anaplastic lymphoma kinase), a cancer-associated receptor tyrosine kinase, was found to play a role in oxidative stress and inflammation. In this study, we investigated the role of ALK inhibition in a murine model of ischemic stroke. METHODS: Focal cerebral ischemia was induced by temporary occlusion of the right middle cerebral artery in mice with a filament. The ALK inhibitor alectinib was administered following the stroke. ALOX15 (arachidonic acid 15-lipoxygenase) was overexpressed by adenovirus injection. The immunohistochemistry, Western blot, oxidative stress, inflammation, blood-brain barrier leakage, infarct volume, and functional outcomes were determined. RESULTS: We found that the expression of ALK was markedly increased in the neurovascular unit after cerebral ischemia. Treatment with the ALK inhibitor alectinib reduced the accumulation of reactive oxygen species, lipid peroxidation, and oxidative DNA, increased the vascular levels of antioxidant enzymes, inactivated the vascular NLRP3 (nucleotide-binding oligomerization domain-like receptor protein 3) inflammasome pathway, and reduced vascular inflammation (ICAM-1 [intercellular adhesion molecule-1] and MCP-1 [monocyte chemoattractant protein-1]) after ischemia. Moreover, alectinib reduced the loss of cerebrovascular integrity and blood-brain barrier damage, consequently decreasing brain infarction and neurological deficits. Furthermore, alectinib reduced stroke-evoked ALOX15 expression, whereas virus-mediated overexpression of ALOX15 abolished alectinib-dependent inhibition of oxidative stress and vascular inflammation, blood-brain barrier protection, and neuroprotection, suggesting the protective effects of alectinib for stroke may involve ALOX15. CONCLUSIONS: Our findings demonstrated that alectinib protects from stroke by regulating ischemic signaling cascades and suggest that ALK may be a novel therapeutic target for ischemic stroke.

Autophagy-related 5 in acute ischemic stroke: Variation and linkage with neurofunction, and survival.

OBJECTIVE: Autophagy-related 5 (ATG5) facilitates the pathologic process of acute ischemic stroke (AIS) via multiple ways. This study aimed to identify the association of serum ATG5 with clinical outcomes in AIS patients. METHODS: Serum ATG5 from 280 AIS patients were detected at admission, Day (D)1, D3, D7, D30, and D90 after admission by enzyme-linked immunosorbent assay. The median (interquartile range) follow-up was 21.1 (5.9-43.9) months. Another 50 healthy controls (HCs) were also enrolled for serum ATG5 determination. RESULTS: ATG5 was elevated (p < 0.001) (vs. HCs), and positively correlated with hyperlipidemia (p = 0.016), and the national institutes of health stroke scale score (p = 0.001) in AIS patients. Interestingly, ATG5 was increased from admission to D1, but gradually decreased until D90 (p < 0.001). Besides, 85 (30.4%) and 195 (69.6%) AIS patients were assessed as modified Rankin Scale (mRS) >2 and mRS ≤2 at D90, respectively. ATG5 at admission, D1, D3, D30, and D90 was elevated in AIS patients with mRS >2 versus those with mRS ≤2 (all p < 0.050). ATG5 at admission, D1, D3, D7, D30, or D90 was elevated in relapsed (vs. non-relapsed) or died (vs. survived) AIS patients (all p < 0.050). Recurrence-free survival was shortened in AIS patients with high (≥52.0 ng/mL) ATG5 versus those with low (<52.0 ng/mL) ATG5 at admission, D3, D7, and D30 (all p < 0.050); overall survival was shorter in AIS patients with high (vs. low) ATG5 at D7 and D30 (both p < 0.050). INTERPRETATION: Serum ATG5 elevates at first, thereafter gradually declines, whose elevation associates with neurological dysfunction, recurrence, and death risk in AIS patients.

Experimental Study: The Effect Of 20% Intralipid Emulsion Therapy In Cerebral Ischemic Reperfusion.

BACKGROUND: This experimental study was conducted to investigate the effect of 20% Intralipid Emulsion (ILE) treatment on Cerebral Ischemia Reperfusion Injury (CIRI) after reperfusion in acute ischemic stroke. METHODS: In this experimental study, seven rats without any intervention (control group), seven rats (sham group) for which CIRI was created after the common carotid artery was ligated for 2 hours, and seven rats who were treated with 20% ILE after CIRI (CIRI + ILE group) were sacrificed after 24 hours, and histopathological findings were investigated. RESULTS: In rats that were not treated after CIRI, 52.7% had level-1, 32.7% had level-2. and 14.5% had level-3. histopathological findings. While 72.2% of the rats treated with ILE had level-1 and 27.8% had level-2 findings, no level-3 histopathological findings were detected in any of the rats. While no signs of coagulative necrosis, spongiosis of surrounding tissue and polymorphonuclear leukocytes were observed histopathological in any of the rats given ILE, there was no macrophages finding in 85.6% of the rats. ILE treatment also reduced the histopathological findings of eosinophilic neurons, astrogliosis, neovascularization, vascular thrombosis and mononuclear inflammatory cells. CONCLUSION: This study showed that 20% ILE treatment reduces the histopathological damage seen in cerebral ischemia and CIRI.

Hippocampal capillary pericytes in post-stroke and vascular dementias and Alzheimer's disease and experimental chronic cerebral hypoperfusion.

Neurovascular unit mural cells called 'pericytes' maintain the blood-brain barrier and local cerebral blood flow. Pathological changes in the hippocampus predispose to cognitive impairment and dementia. The role of hippocampal pericytes in dementia is largely unknown. We investigated hippocampal pericytes in 90 post-mortem brains from post-stroke dementia (PSD), vascular dementia (VaD), Alzheimer's disease (AD), and AD-VaD (Mixed) subjects, and post-stroke non-demented survivors as well as similar age controls. We used collagen IV immunohistochemistry to determine pericyte densities and a mouse model of VaD to validate the effects of chronic cerebral hypoperfusion. Despite increased trends in hippocampal microvascular densities across all dementias, mean pericyte densities were reduced by ~25-40% in PSD, VaD and AD subjects compared to those in controls, which calculated to 14.1 ± 0.7 per mm capillary length, specifically in the cornu ammonis (CA) 1 region (P = 0.01). In mice with chronic bilateral carotid artery occlusion, hippocampal pericyte loss was ~60% relative to controls (P < 0.001). Pericyte densities were correlated with CA1 volumes (r = 0.54, P = 0.006) but not in any other sub-region. However, mice subjected to the full-time environmental enrichment (EE) paradigm showed remarkable attenuation of hippocampal CA1 pericyte loss in tandem with CA1 atrophy. Our results suggest loss of hippocampal microvascular pericytes across common dementias is explained by a vascular aetiology, whilst the EE paradigm offers significant protection.

Set7/9 aggravates ischemic brain injury via enhancing glutamine metabolism in a blocking Sirt5 manner.

The aberrant expression of methyltransferase Set7/9 plays a role in various diseases. However, the contribution of Set7/9 in ischemic stroke remains unclear. Here, we show ischemic injury results in a rapid elevation of Set7/9, which is accompanied by the downregulation of Sirt5, a deacetylase reported to protect against injury. Proteomic analysis identifies the decrease of chromobox homolog 1 (Cbx1) in knockdown Set7/9 neurons. Mechanistically, Set7/9 promotes the binding of Cbx1 to H3K9me2/3 and forms a transcription repressor complex at the Sirt5 promoter, ultimately repressing Sirt5 transcription. Thus, the deacetylation of Sirt5 substrate, glutaminase, which catalyzes the hydrolysis of glutamine to glutamate and ammonia, is decreased, promoting glutaminase expression and triggering excitotoxicity. Blocking Set7/9 eliminates H3K9me2/3 from the Sirt5 promoter and normalizes Sirt5 expression and Set7/9 knockout efficiently ameliorates brain ischemic injury by reducing the accumulation of ammonia and glutamate in a Sirt5-dependent manner. Collectively, the Set7/9-Sirt5 axis may be a promising epigenetic therapeutic target.

Neuroprotection of rhubarb extract against cerebral ischaemia-reperfusion injury via the gut-brain axis pathway.

BACKGROUND: The gut-brain axis (GBA) plays a central role in cerebral ischaemia-reperfusion injury (CIRI). Rhubarb, known for its purgative properties, has demonstrated protective effects against CIRI. However, it remains unclear whether this protective effect is achieved through the regulation of the GBA. AIM: This study aims to investigate the mechanism by which rhubarb extract improves CIRI by modulating the GBA pathway. METHODS: We identified the active components of rhubarb extract using LC-MS/MS. The model of middle cerebral artery occlusion (MCAO) was established to evaluate the effect of rhubarb extract. We conducted 16S rDNA sequencing and untargeted metabolomics to analyze intestinal contents. Additionally, we employed HE staining, TUNEL staining, western blot, and ELISA to assess intestinal barrier integrity. We measured the levels of inflammatory cytokines in serum via ELISA. We also examined blood-brain barrier (BBB) integrity using Evans blue (EB) penetration, transmission electron microscopy (TEM), western blot, and ELISA. Neurological function scores and TTC staining were utilized to evaluate neurological outcomes. RESULTS: We identified twenty-six active components in rhubarb. Rhubarb extract enhanced α-diversity, reduced the abundance of Enterobacteriaceae, and partially rectified metabolic disorders in CIRI rats. It also ameliorated pathological changes, increased the expressions of ZO-1, Occludin, and Claudin 1 in the colon, and reduced levels of LPS and d-lac in serum. Furthermore, it lowered the levels of IL-1ß, IL-6, IL-10, IL-17, and TNF-α in serum. Rhubarb extract mitigated BBB dysfunction, as evidenced by reduced EB penetration and improved hippocampal microstructure. It upregulated the expressions of ZO-1, Occludin, Claudin 1, while downregulating the expressions of TLR4, MyD88, and NF-κB. Similarly, rhubarb extract decreased the levels of IL-1ß, IL-6, and TNF-α in the hippocampus. Ultimately, it reduced neurological function scores and cerebral infarct volume. CONCLUSION: Rhubarb effectively treats CIRI, potentially by inhibiting harmful bacteria, correcting metabolic disorders, repairing intestinal barrier function, alleviating BBB dysfunction, and ultimately improving neurological outcomes.

Development of a new cerebral ischemia reperfusion model of Mongolian gerbils and standardized evaluation system.

BACKGROUND: The Mongolian gerbil is an excellent laboratory animal for preparing the cerebral ischemia model due to its inherent deficiency in the circle of Willis. However, the low incidence and unpredictability of symptoms are caused by numerous complex variant types of the circle. Additionally, the lack of an evaluation system for the cerebral ischemia/reperfusion (I/R) model of gerbils has shackled the application of this model. METHODS: We created a symptom-oriented principle and detailed neurobehavioral scoring criteria. At different time points of reperfusion, we analyzed the alteration in locomotion by rotarod test and grip force score, infarct volume by triphenyltetrazolium chloride (TTC) staining, neuron loss using Nissl staining, and histological characteristics using hematoxylin-eosin (H&E) straining. RESULTS: With a successful model rate of 56%, 32 of the 57 gerbils operated by our method harbored typical features of cerebral I/R injury, and the mortality rate in the male gerbils was significantly higher than that in the female gerbils. The successfully prepared I/R gerbils demonstrated a significant reduction in motility and grip strength at 1 day after reperfusion; formed obvious infarction; exhibited typical pathological features, such as tissue edema, neuronal atrophy and death, and vacuolated structures; and were partially recovered with the extension of reperfusion time. CONCLUSION: This study developed a new method for the unilateral common carotid artery ligation I/R model of gerbil and established a standardized evaluation system for this model, which could provide a new cerebral I/R model of gerbils with more practical applications.

Integrating spatial and single-cell transcriptomics to characterize the molecular and cellular architecture of the ischemic mouse brain.

Neuroinflammation is acknowledged as a pivotal pathological event after cerebral ischemia. However, there is limited knowledge of the molecular and spatial characteristics of nonneuronal cells, as well as of the interactions between cell types in the ischemic brain. Here, we used spatial transcriptomics to study the ischemic hemisphere in mice after stroke and sequenced the transcriptomes of 19,777 spots, allowing us to both visualize the transcriptional landscape within the tissue and identify gene expression profiles linked to specific histologic entities. Cell types identified by single-cell RNA sequencing confirmed and enriched the spatial annotation of ischemia-associated gene expression in the peri-infarct area of the ischemic hemisphere. Analysis of ligand-receptor interactions in cell communication revealed galectin-9 to cell-surface glycoprotein CD44 (LGALS9-CD44) as a critical signaling pathway after ischemic injury and identified microglia and macrophages as the main source of galectins after stroke. Extracellular vesicle-mediated Lgals9 delivery improved the long-term functional recovery in photothrombotic stroke mice. Knockdown of Cd44 partially reversed these therapeutic effects, inhibiting oligodendrocyte differentiation and remyelination. In summary, our study provides a detailed molecular and cellular characterization of the peri-infact area in a murine stroke model and revealed Lgals9 as potential treatment target that warrants further investigation.

Indole-3-carbinol (I3C) reduces apoptosis and improves neurological function after cerebral ischemia-reperfusion injury by modulating microglia inflammation.

Indole-3-carbinol(I3C) is a tumor chemopreventive substance that can be extracted from cruciferous vegetables. Indole-3-carbinol (I3C) has been shown to have antioxidant and anti-inflammatory effects. In this study, we investigated the cerebral protective effects of I3C in an in vivo rats model of middle cerebral artery occlusion (MCAO). 8-10 Week-Old male SD rat received I3C (150 mg/kg, once daily) for 3 days and underwent 3 h of middle cerebral artery occlusion (MCAO) followed by reperfusion. The results showed that I3C pretreatment (150 mg/kg, once daily) prevented CIRI-induced cerebral infarction in rats. I3C pretreatment also decreased the mRNA expression levels of several apoptotic proteins, including Bax, caspase-3 and caspase-9, by increasing the mRNA expression levels of the anti-apoptotic protein Bcl-2. Inhibited apoptosis in the brain cells of MCAO rats. In addition, we found that I3C pretreatment reduced neuronal loss, promoted neurological recovery after ischemia-reperfusion injury and increased seven-day survival in MCAO rats. I3C pretreatment also significantly reduced the expression of inducible nitric oxide synthase (INOS), interleukin-1ß (IL-1ß) and interleukin-6 (IL-6) mRNA in ischemic brain tissue; Increased expression of interleukin-4 (IL-4) and interleukin-10 (IL-10) mRNA. At the same time, I3C pretreatment significantly decreased the expression of the M1 microglial marker IBA1 after cerebral ischemia-reperfusion injury and increased the expression of these results in the M2 microglial marker CD206. I3C pretreatment also significantly decreased apoptosis and death of HAPI microglial cells after hypoxia induction, decreased interleukin-1ß (IL-1ß) and interleukin-6 (IL-6) mRNA The expression of interleukin-4 (IL-4) and interleukin-10 (IL-10) mRNAs was increased. These results suggest that I3C protects the brain from CIRI by regulating the anti-inflammatory and anti-apoptotic effects of microglia.

Prolonged myelin deficits contribute to neuron loss and functional impairments after ischaemic stroke.

Ischaemic stroke causes neuron loss and long-term functional deficits. Unfortunately, effective approaches to preserving neurons and promoting functional recovery remain unavailable. Oligodendrocytes, the myelinating cells in the CNS, are susceptible to oxygen and nutrition deprivation and undergo degeneration after ischaemic stroke. Technically, new oligodendrocytes and myelin can be generated by the differentiation of oligodendrocyte precursor cells (OPCs). However, myelin dynamics and their functional significance after ischaemic stroke remain poorly understood. Here, we report numerous denuded axons accompanied by decreased neuron density in sections from ischaemic stroke lesions in human brain, suggesting that neuron loss correlates with myelin deficits in these lesions. To investigate the longitudinal changes in myelin dynamics after stroke, we labelled and traced pre-existing and newly-formed myelin, respectively, using cell-specific genetic approaches. Our results indicated massive oligodendrocyte death and myelin loss 2 weeks after stroke in the transient middle cerebral artery occlusion (tMCAO) mouse model. In contrast, myelin regeneration remained insufficient 4 and 8 weeks post-stroke. Notably, neuronal loss and functional impairments worsened in aged brains, and new myelin generation was diminished. To analyse the causal relationship between remyelination and neuron survival, we manipulated myelinogenesis by conditional deletion of Olig2 (a positive regulator) or muscarinic receptor 1 (M1R, a negative regulator) in OPCs. Deleting Olig2 inhibited remyelination, reducing neuron survival and functional recovery after tMCAO. Conversely, enhancing remyelination by M1R conditional knockout or treatment with the pro-myelination drug clemastine after tMCAO preserved white matter integrity and neuronal survival, accelerating functional recovery. Together, our findings demonstrate that enhancing myelinogenesis is a promising strategy to preserve neurons and promote functional recovery after ischaemic stroke.

Nuciferine reduces inflammation induced by cerebral ischemia-reperfusion injury through the PI3K/Akt/NF-κB pathway.

BACKGROUND: Cerebral ischemia has the characteristics of high incidence, mortality, and disability, which seriously damages people's health. Cerebral ischemia-reperfusion injury is the key pathological injury of this disease. However, there is a lack of drugs that can reduce cerebral ischemia-reperfusion injury in clinical practice. At present, a few studies have provided some evidence that nuciferine can reduce cerebral ischemia-reperfusion injury, but its specific mechanism of action is still unclear, and further research is still needed. OBJECTIVE: In this study, PC12 cells and SD rats were used to construct OGD/R and MCAO/R models, respectively. Combined with bioinformatics methods and experimental verification methods, the purpose of this study was to conduct a systematic and comprehensive study on the effect and mechanism of nuciferine on reducing inflammation induced by cerebral ischemia-reperfusion injury. RESULTS: Nuciferine can improve the cell viability of PC12 cells induced by OGD/R, reduce apoptosis, and reduce the expression of inflammation-related proteins; it can also improve the cognitive and motor dysfunction of MCAO/R-induced rats by behavioral tests, reduce the area of cerebral infarction, reduce the release of inflammatory factors TNF-α and IL-6 in serum and the expression of inflammation-related proteins in brain tissue. CONCLUSION: Nuciferine can reduce the inflammatory level of cerebral ischemia-reperfusion injury in vivo and in vitro models by acting on the PI3K/Akt/NF-κB signaling pathway, and has the potential to be developed as a drug for the treatment of cerebral ischemia-reperfusion injury.

Synergistic effects and molecular mechanisms of DL-3-n-butylphthalide combined with dual antiplatelet therapy in acute ischemic stroke.

DL-3-n-butylphthalide (NBP) is isolated from the seeds of Apium graveolens L., and has been recently used as a neuroprotective agent for acute ischemic stroke. The present study aimed to determine the efficacy and safety of the combined use of dual antiplatelet therapy (DAPT) and NBP for treating of acute ischemic stroke in rats and to explore the synergistic mechanism of this treatment strategy in rat middle cerebral artery occlusion models. The efficacy of DAPT combined with NBP was evaluated by determining neurological deficits, infarction status, and histological changes. Changes in body weight, blood glucose level, blood count, and serum biochemical parameters were detected to evaluate the safety. To explore the synergistic pharmacological mechanism, the mRNA expression and protein levels of key proteins in the pyroptosis-inflammatory pathway, and the pyroptosis ratio of microglias were examined. Compared with the administration of NBP or DAPT alone, combination of them significantly improved neurological deficits, reduced infarct area, and repaired tissue injury and inflammation after cerebral ischemia. No hepatorenal toxicity was observed. The mRNA expression and protein levels of key proteins in the pyroptosis-inflammation pathway, and the pyroptosis ratio of microglias were significantly downregulated in the combined administration group than in the monotherapy group. We demonstrated that the combined use of NBP and DAPT exhibits better efficacy and high safety and plays a synergistic role by inhibiting the pyroptosis-inflammation pathway in the brain tissues, particularly in microglial cells.

Ethoxyquin, a Lipid Peroxidation Inhibitor, Has Protective Effects against White Matter Lesions in a Mouse Model of Chronic Cerebral Hypoperfusion.

White matter lesions induced by chronic cerebral hypoperfusion can cause vascular dementia; however, no appropriate treatments are currently available for these diseases. In this study, we investigated lipid peroxidation, which has recently been pointed out to be associated with cerebrovascular disease and vascular dementia, as a therapeutic target for chronic cerebral hypoperfusion. We used ethoxyquin, a lipid-soluble antioxidant, in a neuronal cell line and mouse model of the disease. The cytoprotective effect of ethoxyquin on glutamate-stimulated HT-22 cells, a mouse hippocampal cell line, was comparable to that of a ferroptosis inhibitor. In addition, the administration of ethoxyquin to bilateral common carotid artery stenosis model mice suppressed white matter lesions, blood-brain barrier disruption, and glial cell activation. Taken together, we propose that the inhibition of lipid peroxidation may be a useful therapeutic approach for chronic cerebrovascular disease and the resulting white matter lesions.

White matter hyperintensity burden and collateral circulation in acute ischemic stroke with large artery occlusion.

OBJECTIVE: This study aimed to investigate the association between white matter hyperintensity (WMH) burden and pial collaterals in acute strokes caused by intracranial large artery occlusion treated with mechanical thrombectomy in the anterior circulation, focusing on stroke subtypes. METHODS: Consecutive patients undergoing mechanical thrombectomy between December 2019 and June 2022 were retrospectively screened. The Fazekas scale assessed WMH burden. Pial collaterals were categorized as either poor (0-2) or good (3-4) based on the Higashida score. A multivariable analysis was used to determine the relationship between WMH burden and pial collaterals. Subgroup analyses delved into associations stratified by stroke subtypes, namely cardioembolism (CE), tandem lesions (TLs), and intracranial atherosclerosis (ICAS). RESULTS: Of the 573 patients included, 274 (47.8%) demonstrated poor pial collaterals. Multivariable regression indicated a strong association between extensive WMH burden (Fazekas score of 3-6) and poor collaterals [adjusted OR 3.04, 95% CI 1.70-5.46, P < 0.001]. Additional independent predictors of poor collaterals encompassed ICAS-related occlusion (aOR 0.26, 95% CI 0.09-0.76, P = 0.014), female sex (aOR 0.63, 95% CI 0.41-0.96, P = 0.031), and baseline Alberta Stroke Program Early Computed Tomography scores (aOR 0.80, 95% CI 0.74-0.88, P < 0.001). Notably, an interaction between extensive WMH burden and stroke subtypes was observed in predicting poor collaterals (P = 0.001), being pronounced for CE (adjusted OR 2.30, 95% CI 1.21-4.37) and TLs (adjusted OR 5.09, 95% CI 2.32-11.16), but was absent in ICAS (adjusted OR 1.24, 95% CI 0.65-2.36). CONCLUSIONS: Among patients treated with mechanical thrombectomy for anterior circulation large artery occlusion, extensive WMH burden correlates with poor pial collaterals in embolic occlusion cases (CE and TLs), but not in ICAS-related occlusion.

Modeling diffusion-weighted imaging lesion expansion between 2 and 24 h after endovascular thrombectomy in acute ischemic stroke.

PURPOSE: Diffusion-weighted imaging (DWI) lesion expansion after endovascular thrombectomy (EVT) is not well characterized. We used serial diffusion-weighted magnetic resonance imaging (MRI) to measure lesion expansion between 2 and 24 h after EVT. METHODS: In this single-center observational analysis of patients with acute ischemic stroke due to large vessel occlusion, DWI was performed post-EVT (< 2 h after closure) and 24-h later. DWI lesion expansion was evaluated using multivariate generalized linear mixed modeling with various clinical moderators. RESULTS: We included 151 patients, of which 133 (88%) had DWI lesion expansion, defined as a positive change in lesion volume between 2 and 24 h. In an unadjusted analysis, median baseline DWI lesion volume immediately post-EVT was 15.0 mL (IQR: 6.6-36.8) and median DWI lesion volume 24 h post-EVT was 20.8 mL (IQR: 9.4-66.6), representing a median change of 6.1 mL (IQR: 1.5-17.7), or a 39% increase. There were no significant associations among univariable models of lesion expansion. Adjusted models of DWI lesion expansion demonstrated that relative lesion expansion (defined as final/initial DWI lesion volume) was consistent across eTICI scores (0-2a, 0.52%; 2b, 0.49%; 2c-3, 0.42%, p = 0.69). For every 1 mL increase in lesion volume, there was 2% odds of an increase in 90-day mRS (OR: 1.021, 95%CI [1.009, 1.034], p < 0.001). CONCLUSION: We observed substantial lesion expansion post-EVT whereby relative lesion expansion was consistent across eTICI categories, and greater absolute lesion expansion was associated with worse clinical outcome. Our findings suggest that alternate endpoints for cerebroprotectant trials may be feasible.

Salvianolic acid A provides neuroprotective effects on cerebral ischemia-reperfusion injury in rats via PKA/CREB/c-Fos signaling pathway.

BACKGROUND: Cerebral ischemia-reperfusion injury (CIRI) is a phenomenon that pathological injury of ischemic brain tissue is further aggravated after the restoration of blood supply. The complex pathological mechanism of CIRI has led to the failure of multiple neuroprotective agents in clinical studies. Salvianolic acid A (SAA) is a neuroprotective extract from Salvia miltiorrhiza Bge., with significant pharmacological activities in the treatment of brain injury. However, the neuroprotective mechanisms of SAA remain unclear. PURPOSE: To explore the potential protective effect of SAA on CIRI and its mechanism, and to provide experimental basis for the research of new drugs for CIRI. STUDY DESIGN: A model of transient middle cerebral artery occlusion (tMCAO) in rats was used to simulate clinical CIRI, and the neuroprotective effect of SAA on tMCAO rats was investigated within 14 days after reperfusion. The improvement effects of SAA on cognitive impairment of tMCAO rats were investigated by behavioral tests from days 7-14. Finally, the neuroprotective mechanism of SAA was investigated on day 14. METHODS: The neuroprotective effects and mechanism of SAA were investigated by behavioral tests, HE and TUNEL staining, RNA sequence (RNA-seq) analysis and Western blot in tMCAO rats. RESULTS: The brain protective effects of SAA were achieved by alleviating cerebral infarction, cerebral edema, cerebral atrophy and nerve injury in tMCAO rats. Meanwhile, SAA could effectively improve the cognitive impairment and pathological damage of hippocampal tissue, and inhibit cell apoptosis in tMCAO rats. Besides, SAA could provide neuroprotective effects by up-regulating the expression of Bcl-2, inhibiting the activation of Caspase 3, and regulating PKA/CREB/c-Fos signaling pathway. CONCLUSION: SAA can significantly improve brain injury and cognitive impairment in CIRI rats, and this neuroprotective effect may be achieved through the anti-apoptotic effect and the regulation of PKA/CREB/c-Fos signaling pathway.

A toolkit for stroke infarct volume estimation in rodents.

Stroke volume is a key determinant of infarct severity and an important metric for evaluating treatments. However, accurate estimation of stroke volume can be challenging, due to the often confined 2-dimensional nature of available data. Here, we introduce a comprehensive semi-automated toolkit to reliably estimate stroke volumes based on (1) whole brains ex-vivo magnetic resonance imaging (MRI) and (2) brain sections that underwent immunofluorescence staining. We located and quantified infarct areas from MRI three days (acute) and 28 days (chronic) after photothrombotic stroke induction in whole mouse brains. MRI results were compared with measures obtained from immunofluorescent histologic sections of the same brains. We found that infarct volume determined by post-mortem MRI was highly correlated with a deviation of only 6.6 % (acute) and 4.9 % (chronic) to the measurements as determined in the histological brain sections indicating that both methods are capable of accurately assessing brain tissue damage (Pearson r > 0.9, p < 0.001). The Dice similarity coefficient (DC) showed a high degree of coherence (DC > 0.8) between MRI-delineated regions of interest (ROIs) and ROIs obtained from histologic sections at four to six pre-defined landmarks, with histology-based delineation demonstrating higher inter-operator similarity compared to MR images. We further investigated stroke-related scarring and post-ischemic angiogenesis in cortical peri­infarct regions and described a negative correlation between GFAP+fluorescence intensity and MRI-obtained lesion size.