Global brain inflammation in stroke

Partial blood replacement ameliorates middle cerebral artery occlusion generated neurological aberrations by intervening TLR4 and NLRP3 cascades in rats

Acute ischemic stroke is a catastrophic medical condition that causes severe disability and mortality if the sufferer escapes treatment within a stipulated timeframe. While timely intervention with clot-bursting agents like tissue-plasminogen activators abrogates some post-stroke neurologic deficits, no neuroprotective therapy is yet promisingly addresses the post-recanalization neuroinflammation in post-stroke survivors. Herein, we investigated the effect of partial blood replacement therapy (BRT), obtained from healthy and treadmill-trained donor rats, on neurological deficits, and peripheral and central inflammatory cascades using the ischemia-reperfusion animal paradigm. The cerebral ischemia-reperfusion was induced in rats by occlusion of the middle cerebral artery (MCAO) for 90 min, followed by reperfusion. Rats underwent MCAO surgery displayed remarkable sensorimotor and motor deficits in rotarod, foot fault, adhesive removal, and paw whisker tests till 5 days post-surgery. These behavior abnormalities were ameliorated in the BRT-recipient MCAO rats. BRT also reduced the infarct volume and neuronal death in the ipsilateral hemisphere revealed by TTC and cresyl violet staining compared to the MCAO group. Rats received BRT infusion exhibited the reduced expression of glial fibrillary acidic protein, ionized calcium-binding adaptor molecule-1 (Iba-1), and MyD88 on day 5 post-MCAO in immunohistochemistry and immunofluorescent assays. Moreover, elevated levels of toll-like receptor 4 (TLR4) and mRNA expression of IL-1β, TNF-α, matrix metalloproteinase-9 and NLRP3, and decreased levels of zonula occludens-1 in MCAO rats, were reversed following BRT. These findings suggest that the partial BRT may rescind MCAO-induced neurological dysfunctions and cerebral injury by intervening in the TLR4 and NLRP3 pathways in rats.

A novel small-molecular CCR5 antagonist promotes neural repair after stroke

Chemokine receptor 5 (CCR5) is one of the main co-receptors of HIV-1, and has been found to be a potential therapeutic target for stroke. Maraviroc is a classic CCR5 antagonist, which is undergoing clinical trials against stroke. As maraviroc shows poor blood-brain barrier (BBB) permeability, it is of interest to find novel CCR5 antagonists suitable for neurological medication. In this study we characterized the therapeutic potential of a novel CCR5 antagonist A14 in treating ischemic stroke mice. A14 was discovered in screening millions compounds in the Chemdiv library based on the molecular docking diagram of CCR5 and maraviroc. We found that A14 dose-dependently inhibited the CCR5 activity with an IC50 value of 4.29 μM. Pharmacodynamic studies showed that A14 treatment exerted protective effects against neuronal ischemic injury both in vitro and vivo. In a SH-SY5Y cell line overexpressing CCR5, A14 (0.1, 1 μM) significantly alleviated OGD/R-induced cell injury. We found that the expression of CCR5 and its ligand CKLF1 was significantly upregulated during both acute and recovery period in focal cortical stroke mice; oral administration of A14 (20 mg·kg-1·d-1, for 1 week) produced sustained protective effect against motor impairment. A14 treatment had earlier onset time, lower onset dosage and much better BBB permeability compared to maraviroc. MRI analysis also showed that A14 treatment significantly reduced the infarction volume after 1 week of treatment. We further revealed that A14 treatment blocked the protein-protein interaction between CCR5 and CKLF1, increasing the activity of CREB signaling pathway in neurons, thereby improving axonal sprouting and synaptic density after stroke. In addition, A14 treatment remarkably inhibited the reactive proliferation of glial cells after stroke and reduced the infiltration of peripheral immune cells. These results demonstrate that A14 is a promising novel CCR5 antagonist for promoting neuronal repair after ischemic stroke. A14 blocked the protein-protein interaction between CKLF1 and CCR5 after stroke by binding with CCR5 stably, improved the infarct area and promoted motor recovery through reversing the CREB/pCREB signaling which was inhibited by activated CCR5 Gαi pathway, and benefited to the dendritic spines and axons sprouting.

"Lifting Yang to Dredging Du Meridian Manipulation" acupuncture alleviates cerebral ischemia-reperfusion injury by mediating the NF-κB pathway

BACKGROUND

Ischemic stroke is a permanent neurological impairment resulting from the narrowing or blockage of blood vessels in the brain. The effectiveness of "Lifting Yang to Dredging Du Meridian Manipulation" (LYDD) acupuncture in clinical treatment of ischemic stroke patients has been well-established. Nevertheless, its mechanism is still uncertain.

METHODS

MCAO/R rat models at different time points of reperfusion (24, 36, 48 and 72 h) were constructed, and LYDD acupuncture treatment was performed. Zea-Longa score and TTC staining were used for assessing neurological impairment and cerebral infarct in rats, respectively. The pathological changes of cerebral tissue in each group were observed by HE and Nissl's staining. Cerebral tissue from each group was subjected to RNA-seq, and differentially expressed genes (DEGs) were performed for GO and KEGG enrichment analysis, and hub gene was identified based on the String database and MCODE algorithm.

RESULTS

LYDD acupuncture treatment significantly reduced Zea-Longa score, dry-wet weight ratio, infarct area, inflammatory factor levels (IL-1β and TNF-α), cerebral lesions, number of Nissl body and neuronal apoptosis in the MCAO/R model at different time points of reperfusion. A total of 3518 DEGs were identified in the MCAO/R model compared to the control group, and 3461 DEGs were present in the treatment group compared to the MCAO/R model, and they may be implicated in neurotransmitter transmission, synaptic membrane potential, cell junctions, inflammatory response, immune response, cell cycle, and ECM. The expression trends of BIRC3, LTBR, PLCG2, TLR4 and TRADD mRNAs in the Hub gene were consistent with the RNA-seq results, and LYDD acupuncture treatment significantly inhibited MCAO/R-induced p65 nuclear translocation.

CONCLUSIONS

LYDD acupuncture ameliorates cerebral ischemia-reperfusion injury by inhibiting NF-κB pathway activity.

Group 2 innate lymphoid cells resolve neuroinflammation following cerebral ischaemia

BACKGROUND

Acute brain ischaemia elicits pronounced inflammation, which aggravates neural injury. However, the mechanisms governing the resolution of acute neuroinflammation remain poorly understood. In contrast to regulatory T and B cells, group 2 innate lymphoid cells (ILC2s) are immunoregulatory cells that can be swiftly mobilised without antigen presentation; whether and how these ILC2s participate in central nervous system inflammation following brain ischaemia is still unknown.

METHODS

Leveraging brain tissues from patients who had an ischaemic stroke and a mouse model of focal ischaemia, we characterised the presence and cytokine release of brain-infiltrating ILC2s. The impact of ILC2s on neural injury was evaluated through antibody depletion and ILC2 adoptive transfer experiments. Using Rag2-/-γc-/- mice receiving passive transfer of IL-4-/- ILC2s, we further assessed the contribution of interleukin (IL)-4, produced by ILC2s, in ischaemic brain injury.

RESULTS

We demonstrate that ILC2s accumulate in the areas surrounding the infarct in brain tissues of patients with cerebral ischaemia, as well as in mice subjected to focal cerebral ischaemia. Oligodendrocytes were a major source of IL-33, which contributed to ILC2s mobilisation. Adoptive transfer and expansion of ILC2s reduced brain infarction. Importantly, brain-infiltrating ILC2s reduced the magnitude of stroke injury severity through the production of IL-4.

CONCLUSIONS

Our findings revealed that brain ischaemia mobilises ILC2s to curb neuroinflammation and brain injury, expanding the current understanding of inflammatory networks following stroke.

Development and validation of a random forest model to predict functional outcome in patients with intracerebral hemorrhage

OBJECTIVE

To develop and validate a machine learning (ML)-based model to predict functional outcome in Chinese patients with intracerebral hemorrhage (ICH).

METHODS

This retrospective cohort study enrolled patients with ICH between November 2017 and November 2020. The follow-up period ended in February 2021. The study population was divided into training and testing sets with a ratio of 7:3. All variables were included in the least absolute shrinkage and selection operator (LASSO) regression for feature selection. The selected variables were incorporated into the random forest algorithm to construct the prediction model. The predictive performance of the model was evaluated via the area under the curve (AUC), accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and calibration curve.

RESULTS

A total of 412 ICH patients were included, with 288 in the training set, and 124 in the testing set. Twelve attributes were selected: neurological deterioration, Glasgow Coma Scale (GCS) score at 24 h, baseline GCS score, time from onset to the emergency room, blood glucose, diastolic blood pressure (DBP) change in 24 h, hematoma volume change in 24 h, systemic immune-inflammatory index (SII), systolic blood pressure (SBP) change in 24 h, serum creatinine, serum sodium, and age. In the testing set, the accuracy, AUC, sensitivity, specificity, PPV, and NPV of the model were 0.895, 0.964, 0.872, 0.906, 0.810, and 0.939, respectively. The calibration curves showed a good calibration capability of the model.

CONCLUSION

This developed random forest model performed well in predicting 3-month poor functional outcome for Chinese ICH patients.

The relationship between systemic inflammation index, systemic immune-inflammatory index, and inflammatory prognostic index and 90-day outcomes in acute ischemic stroke patients treated with intravenous thrombolysis

BACKGROUND AND PURPOSE

To explore the association of systemic inflammatory index (SIRI), systemic immune-inflammatory index (SII) and inflammatory prognosis index (IPI) with 90d outcomes in patients with acute ischemic stroke (AIS) after intravenous thrombolysis.

METHODS

The patients who underwent intravenous thrombolysis were enrolled in the present study from September 2019 to December 2022. According to the relevant blood indexes obtained in 24 h after admission, the corresponding values of SIRI, SII and IPI were calculated. The correlation among SIRI, SII, IPI, and admission NIHSS scores was examined by Spearman correlation analysis. ROC curve analysis was conducted to determine the optimal cut-off value of SIRI, SII, IPI, and their corresponding sensitivity and specificity to evaluate their predictive value on admission for poor prognosis. To investigate whether high SIRI, SII, and IPI were independent predictors of poor outcomes within 90 days, variables with P-value < 0.05 during univariate analysis were included in multivariate analysis.

RESULTS

Compared with the good outcome group, the poor outcome group had higher SIRI, IPI, and SII. Spearman correlation analysis showed that the SIRI, IPI, and SII levels significantly correlated with the admission NIHSS score (r = 0.338, 0.356, 0.427, respectively; Ps < 0.001). Univariate analysis and Multivariate logistic regression analysis revealed high SIRI, SII, and IPI values as independent risk factors for poor 90-day prognosis (OR = 1.09, 1.003 and 7.109, respectively).

CONCLUSIONS

High SIRI, IPI, and SII values are correlated with poor 90d outcomes in AIS patients undergoing intravenous thrombolysis.

Shared metabolic shifts in endothelial cells in stroke and Alzheimer's disease revealed by integrated analysis

Since metabolic dysregulation is a hallmark of both stroke and Alzheimer's disease (AD), mining shared metabolic patterns in these diseases will help to identify their possible pathogenic mechanisms and potential intervention targets. However, a systematic integration analysis of the metabolic networks of the these diseases is still lacking. In this study, we integrated single-cell RNA sequencing datasets of ischemic stroke (IS), hemorrhagic stroke (HS) and AD models to construct metabolic flux profiles at the single-cell level. We discovered that the three disorders cause shared metabolic shifts in endothelial cells. These altered metabolic modules were mainly enriched in the transporter-related pathways and were predicted to potentially lead to a decrease in metabolites such as pyruvate and fumarate. We further found that Lef1, Elk3 and Fosl1 may be upstream transcriptional regulators causing metabolic shifts and may be possible targets for interventions that halt the course of neurodegeneration.

Protective effects of Japanese sake yeast on depressive-like behaviors, oxidative stress and inflammatory parameters in a rat model of global cerebral ischemia/reperfusion

Stroke is a serious cerebrovascular disease that causes post-stress depression and death. Stress and inflammation have pivotal roles in the induction of the disease. Several drugs and agents have been used for the treatment of disease, but their uses are faced with limitations owing to their side effects. Natural agents are more efficient for the treatment of stroke due to lower toxicity and their pharmaceutical properties. Sake yeast or Japanese rice wine is an antioxidant compound that could be used to treat stroke and post-stress depression. This study evaluates the effects of sake yeast on depressive-like behaviors, oxidative stress and inflammatory parameters in a rat model of global cerebral ischemia/reperfusion. Rats were divided into four groups, including 1) control: without bilateral common carotid artery occlusion (BCCAO) and sake supplement, 2) Ischemia group: rats induced with BCCAO and lack of therapeutic supplement, and 3 and 4) Ischemia + sake groups: rats induced with BCCAO and treated with 25 and 50 mg/kg sake yeast, respectively. Depressive-like behaviors antioxidant enzymes activities were assessed. The induction of stroke increased oxidant status, inflammatory parameters, and depressive-like behaviors, while the administration of sake could decrease inflammation, depressive-like behaviors, and oxidant status and increase antioxidant enzymes. The yeast could be used as a supplement in combination with other drugs to treat stroke.

Stroke lesion size - Still a useful biomarker for stroke severity and outcome in times of high-dimensional models

BACKGROUND

The volumetric size of a brain lesion is a frequently used stroke biomarker. It stands out among most imaging biomarkers for being a one-dimensional variable that is applicable in simple statistical models. In times of machine learning algorithms, the question arises of whether such a simple variable is still useful, or whether high-dimensional models on spatial lesion information are superior.

METHODS

We included 753 first-ever anterior circulation ischemic stroke patients (age 68.4±15.2 years; NIHSS at 24 h 4.4±5.1; modified Rankin Scale (mRS) at 3-months median[IQR] 1[0.75;3]) and traced lesions on diffusion-weighted MRI. In an out-of-sample model validation scheme, we predicted stroke severity as measured by NIHSS 24 h and functional stroke outcome as measured by mRS at 3 months either from spatial lesion features or lesion size.

RESULTS

For stroke severity, the best regression model based on lesion size performed significantly above chance (p < 0.0001) with R2 = 0.322, but models with spatial lesion features performed significantly better with R2 = 0.363 (t(752) = 2.889; p = 0.004). For stroke outcome, the best classification model based on lesion size again performed significantly above chance (p < 0.0001) with an accuracy of 62.8%, which was not different from the best model with spatial lesion features (62.6%, p = 0.80). With smaller training data sets of only 150 or 50 patients, the performance of high-dimensional models with spatial lesion features decreased up to the point of being equivalent or even inferior to models trained on lesion size. The combination of lesion size and spatial lesion features in one model did not improve predictions.

CONCLUSIONS

Lesion size is a decent biomarker for stroke outcome and severity that is slightly inferior to spatial lesion features but is particularly suited in studies with small samples. When low-dimensional models are desired, lesion size provides a viable proxy biomarker for spatial lesion features, whereas high-precision prediction models in personalised prognostic medicine should operate with high-dimensional spatial imaging features in large samples.

Molecular network mechanism of Shexiang Huayu Xingnao granules in treating intracerebral hemorrhage

We aim to explore the pharmacological efficacy and molecular network mechanism of Shexiang Huayu Xingnao granules (SX granules) in the treatment of intracerebral hemorrhage (ICH) based on experiments and network pharmacology. After the ICH model establishment, the behavioral functions of rats were assessed by the modified neurological severity score (mNSS), the wire suspension test, and the rotarod test. Brain histomorphological changes were observed using 2,3,5-triphenyl tetrazolium chloride (TTC), hematoxylin-eosin (HE), Nissl, and TdT-mediated dUTP nick end labeling (TUNEL) combined with neuronal nuclear (NEUN) immunofluorescence staining. The cross-targets of SX granules and ICH were obtained using network pharmacology, gene ontology (GO) enrichment analysis, and Kyoto encyclopedia of genes and genomes (KEGG) signaling pathway analysis were performed. Then, the obtained Hub genes were verified using real-time quantitative polymerase chain reaction (RT-qPCR). The mNSS score was reduced and the duration to remain wire suspended increased in the SX group. In the morphological experiment, SX granules reduced brain tissue damage, neuronal apoptosis, and the number of astrocytes in the ICH rats. Moreover, 607 targets of drug-disease intersection were obtained by network pharmacology, and 10 Hub genes were found. SX granules regulated the expression of HRAS, MAPK3, and STAT3 in ICH condition. In conclusion, SX granules improved behavioral dysfunction, abnormal alterations in brain tissue, and cell morphology in ICH rats, and potential molecular mechanism was linked with the expression of multiple genes.

Applicability of the low-grade inflammation score in predicting 90-day functional outcomes after acute ischemic stroke

BACKGROUND AND PURPOSE

The low-grade inflammation (LGI) score, a novel indicator of chronic LGI, combines C-reactive protein (CRP), leukocyte counts, the neutrophil/lymphocyte ratio (NLR), and the platelet (PLT) count to predict outcomes of patients with various conditions, such as cardiovascular diseases, cancers, and neurodegenerative diseases. However, few studies have examined the role of the LGI score in predicting functional outcomes of patients with ischemic stroke. The present study aimed to evaluate the association between the LGI score and functional outcomes of patients with ischemic stroke.

METHODS

A total of 1,215 patients were screened in the present study, and 876 patients were finally included in this retrospective observational study based on the inclusion and exclusion criteria. Blood tests were conducted within 24 h of admission. Severity of ischemic stroke was assessed using the NIHSS score with severe stroke denoted by NIHSS > 5. Early neurological deterioration (END) was defined as an increment in the total NIHSS score of ≥ 2 points within 7 days after admission. Patient outcomes were assessed on day 90 after stroke onset using the modified Rankin Scale (mRS).

RESULTS

The LGI score was positively correlated with baseline and the day 7 NIHSS scores (R2 = 0.119, p < 0.001;R2 = 0.123, p < 0.001). Multivariate regression analysis showed that the LGI score was an independent predictor of stroke severity and END. In the crude model, the LGI score in the fourth quartile was associated with a higher risk of poor outcomes on day 90 compared with the LGI score in the first quartile (OR = 5.02, 95% CI: 3.09-8.14, p for trend < 0.001). After adjusting for potential confounders, the LGI score in the fourth quartile was independently associated with poor outcomes on day 90 (OR = 2.65, 95% CI: 1.47-4.76, p for trend = 0.001). Finally, the ROC curve analysis showed an AUC of 0.682 for poor outcomes on day 90 after stroke onset.

CONCLUSION

The LGI score is strongly correlated with the severity of acute ischemic stroke and that the LGI score might be a good predictor for poor outcomes on day 90 in patients with acute ischemic stroke.

H2S-RhoA/ROCK Pathway and Glial Cells in Axonal Remyelination After Ischemic Stroke

Ischemic stroke is one of the main reasons of disability and death. Stroke-induced functional deficits are mainly due to the secondary degeneration of the white matter characterized by axonal demyelination and injury of axon-glial integrity. Enhancement of the axonal regeneration and remyelination could promote the neural functional recovery. However, cerebral ischemia-induced activation of RhoA/Rho kinase (ROCK) pathway plays a crucial and harmful role in the process of axonal recovery and regeneration. Inhibition of this pathway could promote the axonal regeneration and remyelination. In addition, hydrogen sulfide (H2S) has the significant neuroprotective role during the recovery of ischemic stroke via inhibiting the inflammatory response and oxidative stress, regulating astrocyte function, promoting the differentiation of endogenous oligodendrocyte precursor cells (OPCs) to mature oligodendrocyte. Among all of these effects, promoting the formation of mature oligodendrocyte is a crucial part of axonal regeneration and remyelination. Furthermore, numerous studies have uncovered the crosstalk between astrocytes and oligodendrocyte, microglial cells and oligodendrocyte in the axonal remyelination following ischemic stroke. The purpose of this review was to discuss the relationship among H2S, RhoA/ROCK pathway, astrocytes, and microglial cells in the axonal remyelination following ischemic stroke to reveal new strategies for preventing and treating this devastating disease.

Effects of adjuvant berberine therapy on acute ischemic stroke: A meta-analysis

We conducted a meta-analysis to evaluate the clinical efficacy of berberine (BBR) in treating acute ischemic stroke (AIS), explore its anti-inflammatory effects, and assess its potential applications for AIS patients. We comprehensively searched nine databases from inception until July 1, 2022, to identify clinical trials investigating the use of BBR in treating AIS. We performed statistical analyses using RevMan5.4 software and focused on primary outcomes such as inflammatory markers as well as secondary outcomes including immune system indicators, relevant biomarkers, carotid artery atherosclerosis, and adverse reactions. Our analysis included data from 17 clinical trials involving 1670 patients with AIS. Our results revealed that BBR in combination with conventional treatment significantly reduced levels of high-sensitivity C-reactive protein (hs-CRP), macrophage migration inhibitory factor (MIF), interleukin-6 (IL-6), complement C3, hypoxic inducible factor-1 α (HIF-1α), cysteine protease-3 (Caspase-3), the national institutes of health stroke scale (NIHSS), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), carotid intima-media thickness (IMT), the number of unstable plaques, and carotid crouse score on ultrasound when compared with conventional treatment alone. Furthermore, combining BBR with conventional treatment may improve the overall effective rate. Therefore, our findings suggest that BBR can be used as an adjuvant therapy for AIS due to its ability to reduce inflammatory cytokine levels, providing a novel therapeutic option for AIS. However, larger randomized controlled trials are necessary to confirm these results.

Data-driven biomarkers outperform theory-based biomarkers in predicting stroke motor outcomes

Chronic motor impairments are a leading cause of disability after stroke. Previous studies have predicted motor outcomes based on the degree of damage to predefined structures in the motor system, such as the corticospinal tract. However, such theory-based approaches may not take full advantage of the information contained in clinical imaging data. The present study uses data-driven approaches to predict chronic motor outcomes after stroke and compares the accuracy of these predictions to previously-identified theory-based biomarkers. Using a cross-validation framework, regression models were trained using lesion masks and motor outcomes data from 789 stroke patients (293 female/496 male) from the ENIGMA Stroke Recovery Working Group (age 64.9±18.0 years; time since stroke 12.2±0.2 months; normalised motor score 0.7±0.5 (range [0,1]). The out-of-sample prediction accuracy of two theory-based biomarkers was assessed: lesion load of the corticospinal tract, and lesion load of multiple descending motor tracts. These theory-based prediction accuracies were compared to the prediction accuracy from three data-driven biomarkers: lesion load of lesion-behaviour maps, lesion load of structural networks associated with lesion-behaviour maps, and measures of regional structural disconnection. In general, data-driven biomarkers had better prediction accuracy - as measured by higher explained variance in chronic motor outcomes - than theory-based biomarkers. Data-driven models of regional structural disconnection performed the best of all models tested (R2 = 0.210, p < 0.001), performing significantly better than predictions using the theory-based biomarkers of lesion load of the corticospinal tract (R2 = 0.132, p< 0.001) and of multiple descending motor tracts (R2 = 0.180, p < 0.001). They also performed slightly, but significantly, better than other data-driven biomarkers including lesion load of lesion-behaviour maps (R2 =0.200, p < 0.001) and lesion load of structural networks associated with lesion-behaviour maps (R2 =0.167, p < 0.001). Ensemble models - combining basic demographic variables like age, sex, and time since stroke - improved prediction accuracy for theory-based and data-driven biomarkers. Finally, combining both theory-based and data-driven biomarkers with demographic variables improved predictions, and the best ensemble model achieved R2 = 0.241, p < 0.001. Overall, these results demonstrate that models that predict chronic motor outcomes using data-driven features, particularly when lesion data is represented in terms of structural disconnection, perform better than models that predict chronic motor outcomes using theory-based features from the motor system. However, combining both theory-based and data-driven models provides the best predictions.

The role of RhoA/ROCK pathway in the ischemic stroke-induced neuroinflammation

It is widely known that ischemic stroke is the prominent cause of death and disability. To date, neuroinflammation following ischemic stroke represents a complex event, which is an essential process and affects the prognosis of both experimental stroke animals and stroke patients. Intense neuroinflammation occurring during the acute phase of stroke contributes to neuronal injury, BBB breakdown, and worse neurological outcomes. Inhibition of neuroinflammation may be a promising target in the development of new therapeutic strategies. RhoA is a small GTPase protein that activates a downstream effector, ROCK. The up-regulation of RhoA/ROCK pathway possesses important roles in promoting the neuroinflammation and mediating brain injury. In addition, nuclear factor-kappa B (NF-κB) is another vital regulator of ischemic stroke-induced neuroinflammation through regulating the functions of microglial cells and astrocytes. After stroke onset, the microglial cells and astrocytes are activated and undergo the morphological and functional changes, thereby deeply participate in a complicated neuroinflammation cascade. In this review, we focused on the relationship among RhoA/ROCK pathway, NF-κB and glial cells in the neuroinflammation following ischemic stroke to reveal new strategies for preventing the intense neuroinflammation.

Effect and Mechanism of Sodium Butyrate on Neuronal Recovery and Prognosis in Diabetic Stroke

Ischemic stroke is a cerebrovascular lesion caused by local ischemia and hypoxia. Diabetes mellitus (DM) is a chronic inflammatory disease that disturbs immune homeostasis and predisposes patients to ischemic stroke. The mechanism by which DM exacerbates stroke remains unclear, although it may involve disturbances in immune homeostasis. Regulatory T cells (Tregs) play a regulatory role in many diseases, but the mechanism of Tregs in diabetes complicated by stroke remains unclear. Sodium butyrate is a short-chain fatty acid that increases Treg levels. This study examined the role of sodium butyrate in the prognosis of neurological function in diabetic stroke and the mechanism by which Tregs are amplified in the bilateral cerebral hemispheres. We evaluated the brain infarct volume, observed 48-h neuronal injury and 28-day behavioral changes, and calculated the 28-day survival rate in mice. We also measured Treg levels in peripheral blood and brain tissue, recorded changes in the blood‒brain barrier and water channel proteins and neurotrophic changes in mice, measured cytokine levels and peripheral B-cell distribution in bilateral hemispheres and peripheral blood, and examined the polarization of microglia and the distribution of peripheral T-cell subpopulations in bilateral hemispheres. Diabetes significantly exacerbated the poor prognosis and neurological deficits in mice with stroke, and sodium butyrate significantly improved infarct volume, prognosis, and neurological function and showed different mechanisms in brain tissue and peripheral blood. The potential regulatory mechanism in brain tissue involved modulating Tregs/TGF-β/microglia to suppress neuroinflammation, while that in peripheral blood involved improving the systemic inflammatory response through Tregs/TGF-β/T cells.

The Association of the Neutrophil-to-Lymphocyte Ratio, Platelet-to-Lymphocyte Ratio, Lymphocyte-to-Monocyte Ratio and Systemic Inflammation Response Index with Short-Term Functional Outcome in Patients with Acute Ischemic Stroke

Background and Purpose

The aim of this study was to explore the relationship between functional prognosis and the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR) and systemic inflammatory response index (SIRI) in patients with acute ischemic stroke (AIS) at discharge.

Methods

A total of 861 patients with AIS were enrolled between January 2019 and December 2021. Blood cell counts were collected on admission. Logistic regression analysis was performed to assess the relationship between NLR, PLR, LMR, SIRI and adverse functional outcomes (modified Rankin scale score of 3-6) at discharge. We also used receiver operating characteristic (ROC) curves to estimate the overall ability of NLR, PLR, LMR and SIRI to judge short-term functional outcomes. Associations between NLR, PLR, LMR, and SIRI with length of hospital stay were analyzed by Spearman correlation test.

Results

A total of 194 patients (22.5%) had poor functional outcomes at discharge. Multivariate logistic regression analysis showed that NLR (odds ratio [OR], 1.060; 95% confidence interval [CI] 1.004-1.120, P=0.037), PLR (OR, 1.003; 95% CI 1.000-1.005, P=0.018), LMR (OR, 0.872; 95% CI 0.774-0.981, P=0.023) and SIRI (OR, 1.099; 95% CI 1.020-1.184, P=0.013) were independent factors for poor functional outcome. The odds ratios of the highest versus lowest quartiles of NLR, PLR and SIRI were 2.495 (95% CI 1.394-4.466), 1.959 (95% CI 1.138-3.373) and 1.866 (95% CI 1.106-3.146), respectively. The odds ratio of the lowest versus highest quartile of LMR was 2.300 (95% CI 1.331-3.975). The areas under the curve (AUCs) of the NLR, PLR, LMR, and SIRI to discriminate poor functional prognosis were 0.644, 0.587, 0.628, and 0.651, respectively. NLR, LMR, and SIRI were related with the length of hospital stay (P<0.05).

Conclusion

NLR, PLR, LMR, and SIRI were associated with functional outcome at discharge in AIS patients. NLR, LMR and SIRI were related to hospitalization days in patients with AIS.

Distinct molecular profiles of skull bone marrow in health and neurological disorders

The bone marrow in the skull is important for shaping immune responses in the brain and meninges, but its molecular makeup among bones and relevance in human diseases remain unclear. Here, we show that the mouse skull has the most distinct transcriptomic profile compared with other bones in states of health and injury, characterized by a late-stage neutrophil phenotype. In humans, proteome analysis reveals that the skull marrow is the most distinct, with differentially expressed neutrophil-related pathways and a unique synaptic protein signature. 3D imaging demonstrates the structural and cellular details of human skull-meninges connections (SMCs) compared with veins. Last, using translocator protein positron emission tomography (TSPO-PET) imaging, we show that the skull bone marrow reflects inflammatory brain responses with a disease-specific spatial distribution in patients with various neurological disorders. The unique molecular profile and anatomical and functional connections of the skull show its potential as a site for diagnosing, monitoring, and treating brain diseases.

Klotho gene might antagonize ischemic injury in stroke rats by reducing the expression of AQP4 via P38MAPK pathway

OBJECTIVES

This study was aimed at exploring whether klotho improved neurologic function in rats with cerebral infarction by inhibiting P38 mitogen-activated protein kinase (MAPK) activation and thus down-regulating aquaporin 4 (AQP4).

METHODS

In this study, we induced intracerebral Klotho overexpression in 6-week-old Sprague Dawley rats by injecting lentivirus carrying full-length rat Klotho cDNA into the lateral ventricle of the brain, followed by middle cerebral artery occlusion (MCAO) surgery after three days. Neurologic function was evaluated by neurological deficit scores. Infarct volume was assessed by 2,3,5-triphenyl tetrazolium chloride (TTC) staining. The expressions of Klotho, AQP4, and P38 MAPK were detected by Western blot and Immunofluorescence.

RESULTS

when rats were subjected to cerebral ischemia, their neurologic function was impaired, the protein expressions of klotho downregulated, the protein expressions of AQP4 and P38 MAPK increased, and the ratios of AQP4 and P-P38-positive area were significantly increased compared with the sham group rats. LV-KL-induced Klotho overexpression greatly improved neurobehavioral deficits and reduced infarct volume in MCAO rats. Klotho overexpression significantly reduced AQP4 and P38 MAPK pathway-related protein expression levels and the ratios of P-P38 and AQP4-positive area in MCAO rats. In addition, SB203580, a P38 MAPK signal pathway inhibitor, improved neurobehavioral deficits, reduced infarct volume, downregulated the expressions levels of AQP4 and P38 MAPK, and reduced the size of P-P38 and AQP4-positive area in MCAO rats.

CONCLUSION

Klotho could alleviate the infraction volume and neurological dysfunction in MCAO rats, and its mechanism may involve AQP4 expression downregulation by suppressing P38-MAPK activation.

Predicting ischemic stroke risk from atrial fibrillation based on multi-spectral fundus images using deep learning

Background

Ischemic stroke (IS) is one of the most common serious secondary diseases of atrial fibrillation (AF) within 1 year after its occurrence, both of which have manifestations of ischemia and hypoxia of the small vessels in the early phase of the condition. The fundus is a collection of capillaries, while the retina responds differently to light of different wavelengths. Predicting the risk of IS occurring secondary to AF, based on subtle differences in fundus images of different wavelengths, is yet to be explored. This study was conducted to predict the risk of IS occurring secondary to AF based on multi-spectrum fundus images using deep learning.

Methods

A total of 150 AF participants without suffering from IS within 1 year after discharge and 100 IS participants with persistent arrhythmia symptoms or a history of AF diagnosis in the last year (defined as patients who would develop IS within 1 year after AF, based on fundus pathological manifestations generally prior to symptoms of the brain) were recruited. Fundus images at 548, 605, and 810 nm wavelengths were collected. Three classical deep neural network (DNN) models (Inception V3, ResNet50, SE50) were trained. Sociodemographic and selected routine clinical data were obtained.

Results

The accuracy of all DNNs with the single-spectral or multi-spectral combination images at the three wavelengths as input reached above 78%. The IS detection performance of DNNs with 605 nm spectral images as input was relatively more stable than with the other wavelengths. The multi-spectral combination models acquired a higher area under the curve (AUC) scores than the single-spectral models.

Conclusions

The probability of IS secondary to AF could be predicted based on multi-spectrum fundus images using deep learning, and combinations of multi-spectrum images improved the performance of DNNs. Acquiring different spectral fundus images is advantageous for the early prevention of cardiovascular and cerebrovascular diseases. The method in this study is a beneficial preliminary and initiative exploration for diseases that are difficult to predict the onset time such as IS.

Mechanism of PGC-1α-mediated mitochondrial biogenesis in cerebral ischemia-reperfusion injury

Cerebral ischemia-reperfusion injury (CIRI) is a series of cascade reactions that occur after blood flow recanalization in the ischemic zone in patients with cerebral infarction, causing an imbalance in intracellular homeostasis through multiple pathologies such as increased oxygen free radicals, inflammatory response, calcium overload, and impaired energy metabolism, leading to mitochondrial dysfunction and ultimately apoptosis. Rescue of reversibly damaged neurons in the ischemic hemispheric zone is the key to saving brain infarction and reducing neurological deficits. Complex and active neurological functions are highly dependent on an adequate energy supply from mitochondria. Mitochondrial biogenesis (MB), a process that generates new functional mitochondria and restores normal mitochondrial function by replacing damaged mitochondria, is a major mechanism for maintaining intra-mitochondrial homeostasis and is involved in mitochondrial quality control to ameliorate mitochondrial dysfunction and thus protects against CIRI. The main regulator of MB is peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), which improves mitochondrial function to protect against CIRI by activating its downstream nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (TFAM) to promote mitochondrial genome replication and transcription. This paper provides a theoretical reference for the treatment of neurological impairment caused by CIRI by discussing the mechanisms of mitochondrial biogenesis during cerebral ischemia-reperfusion injury.

A Nomogram for Predicting the Recurrence of Acute Non-Cardioembolic Ischemic Stroke: A Retrospective Hospital-Based Cohort Analysis

Non-cardioembolic ischemic stroke (IS) is the predominant subtype of IS. This study aimed to construct a nomogram for recurrence risks in patients with non-cardioembolic IS in order to maximize clinical benefits. From April 2015 to December 2019, data from consecutive patients who were diagnosed with non-cardioembolic IS were collected from Lanzhou University Second Hospital. The least absolute shrinkage and selection operator (LASSO) regression analysis was used to optimize variable selection. Multivariable Cox regression analyses were used to identify the independent risk factors. A nomogram model was constructed using the "rms" package in R software via multifactor Cox regression. The accuracy of the model was evaluated using the receiver operating characteristic (ROC), calibration curve, and decision curve analyses (DCA). A total of 729 non-cardioembolic IS patients were enrolled, including 498 (68.3%) male patients and 231 (31.7%) female patients. Among them, there were 137 patients (18.8%) with recurrence. The patients were randomly divided into training and testing sets. The Kaplan-Meier survival analysis of the training and testing sets consistently revealed that the recurrence rates in the high-risk group were significantly higher than those in the low-risk group (p < 0.01). Moreover, the receiver operating characteristic curve analysis of the risk score demonstrated that the area under the curve was 0.778 and 0.760 in the training and testing sets, respectively. The nomogram comprised independent risk factors, including age, diabetes, platelet-lymphocyte ratio, leukoencephalopathy, neutrophil, monocytes, total protein, platelet, albumin, indirect bilirubin, and high-density lipoprotein. The C-index of the nomogram was 0.752 (95% CI: 0.705~0.799) in the training set and 0.749 (95% CI: 0.663~0.835) in the testing set. The nomogram model can be used as an effective tool for carrying out individualized recurrence predictions for non-cardioembolic IS.

Association between PDE4D rs966221 and the Risk of Ischemic Stroke in Regional Chinese Populations

In published research that includes genome-wide association studies and meta-analyses, the phosphodiesterase 4D (PDE4D) rs966221 variant has been identified as a risk factor in ischemic stroke (IS) in the Caucasian population. Several studies have investigated the relationship between rs966221 and IS susceptibility in Chinese populations over the years but have not provided consistently conclusive results. Therefore, our team performed a new meta-analysis of 5973 IS patients and 6204 controls from qualified studies. We observed no significant link between the PDE4D rs966221 variant and IS in any of the regional Chinese populations. Thus, we performed a subgroup analysis by the geographical distribution of China. Notably, significant associations were observed between rs96622 and the susceptibility of IS in the Northeast Chinese populations (p = 1.00 × 10^-4, odds ratio = 1.28, and 95% confidence interval = 1.13-1.44, I² = 0%). However, rs966221 was not found to be correlated with IS risk in the populations of North, Central, South, and East China. Our meta-analysis demonstrated that the PDE4D rs966221 variant is significantly associated with IS risk in some regional Chinese populations.

Serum amyloid A is a potential predictor of prognosis in acute ischemic stroke patients after intravenous thrombolysis

Objectives

Inflammation shows a notable relationship to acute ischemic stroke's (AIS) occurrence and prognosis. However, existing research has confirmed that serum amyloid A (SAA) is an inflammatory biomarker. The aim of this paper was to investigate the association between SAA and the three-month clinical results of acute AIS patients after intravenous thrombolysis (IVT).

Methods

The evaluation of AIS patients with complete medical records was carried out by prospectively investigating patients hospitalized in our department between January 2020 and February 2023. The SAA levels were examined with the use of an immunosorbent assay kit that shows a relationship with the enzyme (Invitrogen Corp). Patients were dichotomized into favorable (mRS score of 0, 1 or 2) and unfavorable (mRS score of 3, 4, 5, or 6) results with the use of the modified Rankin Scale (mRS).

Results

A total of 405 AIS patients who were subjected to IVT therapy were prospectively covered. To be specific, 121 (29.88%) patients had an unfavorable prognosis during the follow-up for 3 months. On that basis, patients achieving unfavorable results gained notably greater SAA levels (39.77 (IQR 38.32-46.23) vs.31.23 (IQR 27.44-34.47), p < 0.001) during hospitalization in comparison to patients with a better result. In the analysis with multiple variates, SAA was adopted to achieve the independent prediction of the three-month unfavorable clinical results of acute AIS patients after IVT [OR:2.874 (95% CI, 1.764-4.321), p < 0.001]. When the fundamental confounding factors were regulated, the odds ratio (OR) of unfavorable prognosis after AIS patients undergoing IVT therapy was 4.127 (95% CI = 1.695-10.464, p = 0.032) for the maximum tertile of SAA in terms of the minimal tertile. With an AUC of 0.703 (95% CI, 0.649-0.757), SAA revealed a notably more effective discriminating capability in terms of CRP, NLR, EMR, and WBC. SAA as a predictor in terms of the prediction of three-month unfavorable results after AIS patients undergoing IVT therapy achieved specificity and sensitivity of 84.45% and 77.23%, as well as an optimal cut-off value (COV) of 37.39.

Conclusion

SAA level that is up-regulated during hospitalization is capable of serving as an effective marker in terms of the prediction of unfavorable three-month results in AIS patients after IVT.

Lipocalin-2-mediated astrocyte pyroptosis promotes neuroinflammatory injury via NLRP3 inflammasome activation in cerebral ischemia/reperfusion injury

BACKGROUND

Neuroinflammation is a vital pathophysiological process during ischemic stroke. Activated astrocytes play a major role in inflammation. Lipocalin-2 (LCN2), secreted by activated astrocytes, promotes neuroinflammation. Pyroptosis is a pro-inflammatory form of programmed cell death that has emerged as a new area of research in stroke. Nevertheless, the potential role of LCN2 in astrocyte pyroptosis remains unclear.

METHODS

An ischemic stroke model was established by middle cerebral artery occlusion (MCAO) in vivo. In this study, in vitro, oxygen-glucose deprivation and reoxygenation (O/R) were applied to cultured astrocytes. 24p3R (the LCN2 receptor) was inhibited by astrocyte-specific adeno-associated virus (AAV-GFAP-24p3Ri). MCC950 and Nigericin sodium salt (Nig) were used to inhibit or promote the activation of NLRP3 inflammasome pharmacologically, respectively. Histological and biochemical analyses were performed to assess astrocyte and neuron death. Additionally, the neurological deficits of mice were evaluated.

RESULTS

LCN2 expression was significantly induced in astrocytes 24 h after stroke onset in the mouse MCAO model. Lcn2 knockout (Lcn2^-/-) mice exhibited reduced infarct volume and improved neurological and cognitive functions after MCAO. LCN2 and its receptor 24p3R were colocalized in astrocytes. Mechanistically, suppression of 24p3R by AAV-GFAP-24p3Ri alleviated pyroptosis-related pore formation and the secretion of pro-inflammatory cytokines via LCN2, which was then reversed by Nig-induced NLRP3 inflammasome activation. Astrocyte pyroptosis was exacerbated in Lcn2^-/- mice by intracerebroventricular administration of recombinant LCN2 (rLCN2), while this aggravation was restricted by blocking 24p3R or inhibiting NLRP3 inflammasome activation with MCC950.

CONCLUSION

LCN2/24p3R mediates astrocyte pyroptosis via NLRP3 inflammasome activation following cerebral ischemia/reperfusion injury.

Pleocytosis in cerebrospinal fluid attributed to ischemic stroke: A review of the literature

INTRODUCTION

Lumbar puncture is generally performed in stroke settings when infectious or inflammatory diseases are suspected to be the etiology. This review aimed to assess the prevalence of pleocytosis in the cerebrospinal fluid following ischemic stroke without inflammatory or infectious etiology.

METHODS

We searched PubMed for studies with mentions of "[ischemic stroke] AND [cerebrospinal fluid]". We included only studies written in English, including patients with a primary diagnosis of either ischemic stroke or transient ischemic attack (TIA), and where white blood cell count in the spinal fluid was presented. Studies investigating common etiologies for pleocytosis, was excluded. Study and patient characteristics, white blood cell count and time to lumbar puncture were presented in tables, and the prevalence of pleocytosis were reported and plotted graphically.

RESULTS

We included 15 studies with 1607 patients, 1522 with ischemic stroke and 85 with TIA. The prevalence of pleocytosis was between 0% to 28,6% and a mean of 11.8%. The highest white blood cell count found with common etiologies for pleocytosis ruled out was 56 cells/mm3. A mean white blood cell count of 4.0 was based on the three studies where this was available.

DISCUSSION

The included studies were methodologically heterogenous and few had pleocytosis as primary outcome. Pleocytosis following ischemic stroke is uncommon and should prompt further investigations.

CD4+ T cells aggravate hemorrhagic brain injury

Leukocyte infiltration accelerates brain injury following intracerebral hemorrhage (ICH). Yet, the involvement of T lymphocytes in this process has not been fully elucidated. Here, we report that CD4⁺ T cells accumulate in the perihematomal regions in the brains of patients with ICH and ICH mouse models. T cells activation in the ICH brain is concurrent with the course of perihematomal edema (PHE) development, and depletion of CD4⁺ T cells reduced PHE volumes and improved neurological deficits in ICH mice. Single-cell transcriptomic analysis revealed that brain-infiltrating T cells exhibited enhanced proinflammatory and proapoptotic signatures. Consequently, CD4⁺ T cells disrupt the blood-brain barrier integrity and promote PHE progression through interleukin-17 release; furthermore, the TRAIL-expressing CD4⁺ T cells engage DR5 to trigger endothelial death. Recognition of T cell contribution to ICH-induced neural injury is instrumental for designing immunomodulatory therapies for this dreadful disease.

Prognostic value of inflammatory markers for in-hospital mortality in intensive care patients with acute ischemic stroke: a retrospective observational study based on MIMIC-IV

Background

Acute ischemic stroke (AIS) is a primary cause of death and disability worldwide. Four markers that can be readily determined from peripheral blood, namely, the systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and total bilirubin, were measured in this study. We examined the relationship between the SII and in-hospital mortality after AIS and evaluated which of the above four indicators was most accurate for predicting in-hospital mortality after AIS.

Methods

We selected patients from the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database who were aged >18 years and who were diagnosed with AIS on admission. We collected the patients' baseline characteristics, including various clinical and laboratory data. To investigate the relationship between the SII and in-hospital mortality in patients with AIS, we employed the generalized additive model (GAM). Differences in in-hospital mortality between the groups were summarized by the Kaplan-Meier survival analysis and the log-rank test. The receiver operating characteristic (ROC) curve analysis was used to assess the accuracy of the four indicators (SII, NLR, PLR, and total bilirubin) for predicting in-hospital mortality in patients with AIS.

Results

The study included 463 patients, and the in-hospital mortality rate was 12.31%. The GAM analysis showed a positive correlation between the SII and in-hospital mortality in patients with AIS, but the correlation was not linear. Unadjusted Cox regression identified a link between a high SII and an increased probability of in-hospital mortality. We also found that patients with an SII of >1,232 (Q2 group) had a considerably higher chance of in-hospital mortality than those with a low SII (Q1 group). The Kaplan-Meier analysis demonstrated that patients with an elevated SII had a significantly lower chance of surviving their hospital stay than those with a low SII. According to the results of the ROC curve analysis, the in-hospital mortality of patients with AIS predicted by the SII had an area under the ROC curve of 0.65, which revealed that the SII had a better discriminative ability than the NLR, PLR, and total bilirubin.

Conclusion

The in-hospital mortality of patients with AIS and the SII were positively correlated, but not linearly. A high SII was associated with a worse prognosis in patients with AIS. The SII had a modest level of discrimination for forecasting in-hospital mortality. The SII was slightly better than the NLR and significantly better than the PLR and total bilirubin for predicting in-hospital mortality in patients with AIS.

The role of high-sensitivity C-reactive protein serum levels in the prognosis for patients with stroke: a meta-analysis

Background

The impact of high-sensitivity C-reactive protein (hs-CRP) as a biomarker of inflammation on the prognosis of stroke patients remains controversial, this study was conducted to evaluate the prognostic value of hs-CRP levels for patients with stroke.

Methods

PubMed, Web of Science, Embase, and Cochrane Library databases were searched from inception to October 28, 2022. Outcome measures were all-cause mortality, recurrent stroke, and poor prognosis. The relationship between the highest versus lowest levels of hs-CRP or per unit increment and outcomes as measured by risk ratio (RR) and corresponding 95% confidence intervals (CI).

Results

A total of 39 articles were eligible for meta-analysis. High hs-CRP levels at admission were associated with mortality among patients with acute ischemic stroke (AIS) [RR = 3.84, 95% CI (2.41 ~ 6.111); p < 0.001], risk of recurrent stroke [RR = 1.88, 95%CI (1.41 ~ 2.52); p < 0.001], and poor prognosis [RR = 1.77, 95% CI (1.59 ~ 1.97); p < 0.001]. The risk ratios for the association of per unit increase in hs-CRP levels with mortality, risk of recurrent stroke, and poor prognosis were as follows, respectively: 1.42 [95% CI (1.19-1.69); p < 0.001], 1.03 [95% CI (1.01-1.04); p = 0.003], and 1.27 [95% CI (1.10-1.47); p = 0.001]. For hemorrhagic stroke (HS), the risk ratios (RR) for the highest versus the lowest (reference) category of hsCRP or per unit increment to all-cause mortality were 4.36 [95% CI (1.38-13.73); p = 0.012] and 1.03 [95% CI (0.98-1.08); p = 0.238].

Conclusion

Hs-CRP levels are strongly associated with mortality, risk of stroke recurrence and poor prognosis in stroke patients. Therefore, hs-CRP levels may contribute to the prognosis prediction of these patients.

Molecular Hydrogen Mediates Neurorestorative Effects After Stroke in Diabetic Rats: the TLR4/NF-κB Inflammatory Pathway

Diabetes is an independent risk factor for stroke and amplifies inflammation. Diabetic stroke is associated with a higher risk of death and worse neural function. The identification of effective anti-inflammatory molecules with translational advantages is particularly important to promote perioperative neurorestorative effects. Applying molecular hydrogen, we measured blood glucose levels before and after middle cerebral artery occlusion (MCAO), 48-h cerebral oedema and infarct volumes, as well as 28-day weight, survival and neurological function. We also measured the levels of TLR4, NF-κB p65, phosphorylated NF-κB p65, catecholamines, acetylcholine and inflammatory factors. All measurements comprehensively showed the positive effect and translational advantage of molecular hydrogen on diabetic stroke. Molecular hydrogen improved the weight, survival and long-term neurological function of rats with diabetic stroke and alleviated changes in blood glucose levels before and after middle cerebral artery occlusion (MCAO), but no difference in circadian rhythm was observed. Molecular hydrogen inhibited the phosphorylation of NF-κB and significantly reduced inflammation. Molecular hydrogen mediates neurorestorative effects after stroke in diabetic rats. The effect is independent of circadian rhythms, indicating translational advantages. The molecular mechanism is related to the TLR4/NF-κB pathway and inflammation. Molecular hydrogen (H2) affects outcomes of ischemic stroke with diabetes mellitus (DM).

Mitochondrial dysfunctions induce PANoptosis and ferroptosis in cerebral ischemia/reperfusion injury: from pathology to therapeutic potential

Ischemic stroke (IS) accounts for more than 80% of the total stroke, which represents the leading cause of mortality and disability worldwide. Cerebral ischemia/reperfusion injury (CI/RI) is a cascade of pathophysiological events following the restoration of blood flow and reoxygenation, which not only directly damages brain tissue, but also enhances a series of pathological signaling cascades, contributing to inflammation, further aggravate the damage of brain tissue. Paradoxically, there are still no effective methods to prevent CI/RI, since the detailed underlying mechanisms remain vague. Mitochondrial dysfunctions, which are characterized by mitochondrial oxidative stress, Ca²⁺ overload, iron dyshomeostasis, mitochondrial DNA (mtDNA) defects and mitochondrial quality control (MQC) disruption, are closely relevant to the pathological process of CI/RI. There is increasing evidence that mitochondrial dysfunctions play vital roles in the regulation of programmed cell deaths (PCDs) such as ferroptosis and PANoptosis, a newly proposed conception of cell deaths characterized by a unique form of innate immune inflammatory cell death that regulated by multifaceted PANoptosome complexes. In the present review, we highlight the mechanisms underlying mitochondrial dysfunctions and how this key event contributes to inflammatory response as well as cell death modes during CI/RI. Neuroprotective agents targeting mitochondrial dysfunctions may serve as a promising treatment strategy to alleviate serious secondary brain injuries. A comprehensive insight into mitochondrial dysfunctions-mediated PCDs can help provide more effective strategies to guide therapies of CI/RI in IS.

Regulatory mechanisms of natural compounds from traditional Chinese herbal medicines on the microglial response in ischemic stroke

BACKGROUND

Development of clinically effective neuroprotective agents for stroke therapy is still a challenging task. Microglia play a critical role in brain injury and recovery after ischemic stroke. Traditional Chinese herbal medicines (TCHMs) are based on a unique therapeutic principle, have various formulas, and have long been widely used to treat stroke. Therefore, the active compounds in TCHMs and their underlying mechanisms of action are attracting increasing attention in the field of stroke drug development.

PURPOSE

To summarize the regulatory mechanisms of TCHM-derived natural compounds on the microglial response in animal models of ischemic stroke.

METHODS

We searched studies published until 10 April 2023 in the Web of Science, PubMed, and ScienceDirect using the following keywords: natural compounds, natural products or phytochemicals, traditional Chinese Medicine or Chinese herbal medicine, microglia, and ischemic stroke. This review was prepared according to PRISMA (Preferred Reporting Item for Systematic Reviews and Meta-Analysis) guidelines.

RESULTS

Natural compounds derived from TCHMs can attenuate the M1 phenotype of microglia, which is involved in the detrimental inflammatory response, via inhibition of NF-κB, MAPKs, JAK/STAT, Notch, TLR4, P2X7R, CX3CR1, IL-17RA, the NLRP3 inflammasome, and pro-oxidant enzymes. Additionally, the neuroprotective response of microglia with the M2 phenotype can be enhanced by activating Nrf2/HO-1, PI3K/AKT, AMPK, PPARγ, SIRT1, CB2R, TREM2, nAChR, and IL-33/ST2. Several clinical trials showed that TCHM-derived natural compounds that regulate microglial responses have significant and safe therapeutic effects, but further well-designed clinical studies are needed.

CONCLUSIONS

Further research regarding the direct targets and potential pleiotropic or synergistic effects of natural compounds would provide a more reasonable approach for regulation of the microglial response with the possibility of successful stroke drug development.

Xiaoxuming decoction cutting formula reduces LPS-stimulated inflammation in BV-2 cells by regulating miR-9-5p in microglia exosomes

The Background: Stroke is one of the leading causes of morbidity and mortality, and the inflammatory mechanism plays a crucial role in stroke-related brain injury and post-ischemic tissue damage. Xiaoxuming decoction (XXMD) is the first prescription for the treatment of "zhongfeng" (a broad concept referring to stroke) in the Tang and Song Dynasties of China and has a significant position in the history of stroke treatment. Through the study of ancient medical records and modern clinical evidence, it is evident that XXMD has significant efficacy in the treatment of stroke and its sequelae, and its pharmacological mechanism may be related to post-stroke inflammation. However, XXMD contains 12 medicinal herbs with complex composition, and therefore, a simplified version of XXMD, called Xiaoxuming decoction cutting (XXMD-C), was derived based on the anti-inflammatory effects of the individual herbs. Therefore, it is necessary to explore and confirm the anti-inflammatory mechanism of XXMD-C. Aim of the study: Based on the previous experiments of our research group, it was found that both XXMD and XXMD-C have anti-inflammatory effects on LPS-induced microglia, and XXMD-C has a better anti-inflammatory effect. Since miRNAs in exosomes also participate in the occurrence and development of cardiovascular diseases, and traditional Chinese medicine can regulate exosomal miRNAs through intervention, this study aims to explore the anti-inflammatory mechanism of XXMD-C in the treatment of post-stroke inflammation through transcriptome sequencing, providing a basis for the application of XXMD-C. Materials and methods: XXMD-C was extracted using water and filtered through a 0.22 μm membrane filter. The main chemical components of the medicinal herbs in XXMD-C were rapidly qualitatively analyzed using ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Cell viability was determined using the CCK-8 assay, and an LPS-induced BV-2 cell inflammation model was established. The expression of inflammatory cytokines was detected using ELISA and Western blot (WB). Extracellular vesicles were extracted using ultracentrifugation, and identified using transmission electron microscopy (TEM), nanoparticle tracking analysis, and WB. Differential miRNAs were screened using smallRNA-seq sequencing, and validated using RT-PCR and Western blot. Results: The UPLC-Q-TOF-MS analysis revealed that representative components including ephedrine, pseudoephedrine, cinnamaldehyde, baicalin, baicalein, wogonin, and ginsenoside Rg1 were detected in XXMD-C. The results of ELISA and WB assays showed that XXMD-C had a therapeutic effect on LPS-induced inflammation in BV-2 cells. TEM, nanoparticle tracking analysis, and WB results demonstrated the successful extraction of extracellular vesicles using high-speed centrifugation. Differential miRNA analysis by smallRNA-seq identified miR-9-5p, which was validated by RT-PCR and WB. Inhibition of miR-9-5p was found to downregulate the expression of inflammatory factors including IL-1β, IL-6, iNOS, and TNF-α. Conclusion: The study found that XXMD-C has anti-neuroinflammatory effects. Through smallRNA-seq sequencing of extracellular vesicles, miR-9-5p was identified as a key miRNA in the mechanism of XXMD-C for treating neuroinflammation, and its in vivo anti-inflammatory mechanism deserves further investigation.

A detection method for neuronal death indicates abnormalities in intracellular membranous components in neuronal cells that underwent delayed death

Acute neuronal degeneration is always preceded under the light and electron microscopes by a stage called microvacuolation, which is characterized by a finely vacuolar alteration in the cytoplasm of the neurons destined to death. In this study, we reported a method for detecting neuronal death using two membrane-bound dyes, rhodamine R6 and DiOC₆(3), which may be associated with the so-called microvacuolation. This new method produced a spatiotemporally similar staining pattern to Fluoro-Jade B in kainic acid-damaged brains in mice. Further experiments showed that increased staining of rhodamine R6 and DiOC₆(3) was observed only in degenerated neurons, but not in glia, erythrocytes, or meninges. Different from Fluoro-Jade-related dyes, rhodamine R6 and DiOC₆(3) staining is highly sensitive to solvent extraction and detergent exposure. Staining with Nile red for phospholipids and filipin III for non-esterified cholesterol supports that the increased staining of rhodamine R6 and DiOC₆(3) might be associated with increased levels of phospholipids and free cholesterol in the perinuclear cytoplasm of damaged neurons. In addition to kainic acid-injected neuronal death, rhodamine R6 and DiOC₆(3) were similarly useful for detecting neuronal death in ischemic models either in vivo or in vitro. As far as we know, the staining with rhodamine R6 or DiOC₆(3) is one of a few histochemical methods for detecting neuronal death whose target molecules have been well defined and therefore may be useful for explaining experimental results as well as exploring the mechanisms of neuronal death. (250 words).

Bioinformatic identification of hub genes Myd88 and Ccl3 and TWS-119 as a potential agent for the treatment of massive cerebral infarction

Background

Massive cerebral infarction (MCI) causes severe neurological deficits, coma and can even result in death. Here, we identified hub genes and pathways after MCI by analyzing microarray data from a murine model of ischemic stroke and identified potential therapeutic agents for the treatment of MCI.

Methods

Microarray expression profiling was performed using the GSE28731 and GSE32529 datasets from the Gene Expression Omnibus (GEO) database. Data from a sham group (n = 6 mice) and a middle cerebral artery occlusion (MCAO) group (n = 7 mice) were extracted to identify common differentially expressed genes (DEGs). After identifying gene interactions, we generated a protein-protein interaction (PPI) network with Cytoscape software. Then, the MCODE plug-in in Cytoscape was used to determine key sub-modules according to MCODE scores. Enrichment analyses were then conducted on DEGs in the key sub-modules to evaluate their biological functions. Furthermore, hub genes were identified by generating the intersections of several algorithms in the cytohubba plug-in; these genes were then verified in other datasets. Finally, we used Connectivity MAP (CMap) to identify potential agents for MCI therapy.

Results

A total of 215 common DEGs were identified and a PPI network was generated with 154 nodes and 947 edges. The most significant key sub-module had 24 nodes and 221 edges. Gene ontology (GO) analysis showed that the DEGs in this sub-module showed enrichment in inflammatory response, extracellular space and cytokine activity in terms of biological process, cellular component and molecular function, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that TNF signaling was the most enriched pathway. Myd88 and Ccl3 were identified as hub genes and TWS-119 was identified as the most potential therapeutic agent by CMap.

Conclusions

Bioinformatic analysis identified two hub genes (Myd88 and Ccl3) for ischemic injury. Further analysis identified TWS-119 as the best potential candidate for MCI therapy and that this target may be associated with TLR/MyD88 signaling.

Protective effects and mechanisms of Yi Qi Huo Xue Fang in cerebral ischemic stroke based on network pharmacology and experimental verification

ETHNOPHARMACOLOGICAL RELEVANCE

Yi Qi Huo Xue Fang (YQHXF) is an effective formula for treating cerebral ischemic stroke (CIS). However, its active ingredients and mechanism of action remain unclear.

AIM OF THE STUDY

This study aimed to reveal the mechanism of action of YQHXF in the treatment of ischemic stroke based on network pharmacology and experimental validation.

MATERIALS AND METHODS

This study identified the chemical components in YQHXF and the components absorbed by rat serum based on UPLC-Q-TOF/MS technology and used network pharmacology to predict key candidate targets. A protein-protein-interaction (P-P-I) network was constructed using String 11.0 database and Cytoscape, and R software for gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis. Finally, molecular docking combined with animal experiments was used to verify network pharmacology results.

RESULTS

This study identified and confirmed 36 chemical components of YQHXF and five chemical ingredients that were absorbed into the blood of rats and screened 66 key candidate targets. All targets in the P-P-I network were mainly related to inflammation and vascular processes. KEGG enrichment results revealed that these 66 key candidate targets were primarily involved in the "AGE-RAGE signaling pathway," "TNF-α signaling pathway, and "T cell receptor signaling pathway." Molecular docking results revealed that Prostaglandin-endoperoxidase synthase 2(PTGS-2), Nitric oxide synthase, endothelial (NOS3), and peroxisome proliferator-activated receptor gamma (PPARG) were more stably bound to their active ingredients. Animal experiments demonstrated that YQHXF promoted M2 polarization, inhibited M1 polarization in microglia, and promoted angiogenesis, which may be related to the PPARG pathway.

CONCLUSION

This study revealed the key active components and effective targets of YQHXF, identified the mechanism of action of YQHXF, laid the foundation for further research on YQHXF, and provided ideas for developing new drugs for CIS.

Red blood cell distribution width to platelet ratio predicts early neurological deterioration in acute ischemic stroke patients receiving intravenous thrombolysis

BACKGROUND

Inflammation plays a prominent role in the pathogenesis and progression of acute ischemic stroke (AIS). The red blood cell distribution width to platelet ratio (RPR) has been demonstrated as a novel biomarker to indicate the severity of inflammatory reaction. This study aimed to explore the association between RPR before intravenous thrombolysis and early neurological deterioration (END) after thrombolysis in AIS patients.

METHODS

AIS patients accepting intravenous thrombolysis were recruited continuously. Postthrombolysis END was defined as death or an increase in the National Institute of Health Stroke Scale (NIHSS) score ≥4 points within 24 h after intravenous thrombolysis compared to the NIHSS score before intravenous thrombolysis. We constructed univariate and multivariate logistic regression analyses to investigate the relationship of RPR before intravenous thrombolysis to postthrombolysis END. Moreover, a receiver operating characteristic (ROC) curve was applied to examine the discriminative utility of RPR before intravenous thrombolysis in predicting postthrombolysis END.

RESULTS

A total of 235 AIS patients were included, and 31 (13.19%) subjects underwent postthrombolysis END. The univariate logistic regression analysis demonstrated that RPR before intravenous thrombolysis was significantly related to postthrombolysis END (odds ratio [OR], 2.162; 95% confidence interval [CI], 1.605-2.912; P < 0.001). After adjusting for potential confounding variables with P < 0.15 in the univariate logistic regression analysis, the difference remained statistically significant (OR, 2.031; 95% CI, 1.436-2.873; P < 0.001). Furthermore, an optimal cutoff value of 7.66 for RPR before intravenous thrombolysis in predicting postthrombolysis END was observed in the ROC curve analysis, and the sensitivity and specificity were calculated as 61.3% and 81.9%, respectively (area under the curve [AUC], 0.772; 95% CI, 0.684-0.860; P < 0.001).

CONCLUSIONS

RPR before intravenous thrombolysis might be an independent risk factor for postthrombolysis END in AIS patients. Elevated levels of RPR before intravenous thrombolysis may predict postthrombolysis END.

Systemic innate myeloid responses to acute ischaemic and haemorrhagic stroke

Acute ischaemic and haemorrhagic stroke account for significant disability and morbidity burdens worldwide. The myeloid arm of the peripheral innate immune system is critical in the immunological response to acute ischaemic and haemorrhagic stroke. Neutrophils, monocytes, and dendritic cells (DC) contribute to the evolution of pathogenic local and systemic inflammation, whilst maintaining a critical role in ongoing immunity protecting against secondary infections. This review aims to summarise the key alterations to myeloid immunity in acute ischaemic stroke, intracerebral haemorrhage (ICH), and subarachnoid haemorrhage (SAH). By integrating clinical and preclinical research, we discover how myeloid immunity is affected across multiple organ systems including the brain, blood, bone marrow, spleen, and lung, and evaluate how these perturbations associate with real-world outcomes including infection. These findings are placed in the context of the rapidly developing field of human immunology, which offers a wealth of opportunity for further research.

Melatonin protects against NMDA-induced retinal ganglion cell injury by regulating the microglia-TNFα-RGC p38 MAPK pathway

Glaucoma, one of the most common ocular neurodegenerative diseases worldwide, is characterized by retinal ganglion cell (RGC) loss. There is a large body of literature that describes the neuroprotective role of melatonin against neurodegenerative diseases by regulating neuroinflammation, although the exact mechanism through which melatonin acts on RGC is still uncertain. This study assessed the protective effects of melatonin using a NMDA-induced RGC injury model, and studied the possible mechanisms involved in this process. Melatonin promoted RGC survival, improved retinal function, and inhibited the apoptosis and necrosis of retinal cells. To understand the mechanism of the neuroprotective effects of melatonin on RGC, microglia and inflammation-related pathways were assessed after melatonin administration and microglia ablation. Melatonin promoted RGC survival by suppressing microglia-derived proinflammatory cytokines, in particular TNFα, which in turn inhibited the activation of p38 MAPK pathway. Inhibiting TNFα or manipulating p38 MAPK pathway protected damaged RGC. Our results suggest that melatonin protects against NMDA-induced RGC injury by inhibiting the microglial TNFα-RGC p38 MAPK pathway. It should be considered a candidate neuroprotective therapy against retinal neurodegenerative diseases.

Whole-brain diffusion tensor imaging predicts 6-month functional outcome in acute intracerebral haemorrhage

INTRODUCTION

Small vessel disease (SVD) causes most spontaneous intracerebral haemorrhage (ICH) and is associated with widespread microstructural brain tissue disruption, which can be quantified via diffusion tensor imaging (DTI) metrics: mean diffusivity (MD) and fractional anisotropy (FA). Little is known about the impact of whole-brain microstructural alterations after SVD-related ICH. We aimed to investigate: (1) association between whole-brain DTI metrics and functional outcome after ICH; and (2) predictive ability of these metrics compared to the pre-existing ICH score.

METHODS

Sixty-eight patients (38.2% lobar) were retrospectively included. We assessed whole-brain DTI metrics (obtained within 5 days after ICH) in cortical and deep grey matter and white matter. We used univariable logistic regression to assess the associations between DTI and clinical-radiological variables and poor outcome (modified Rankin Scale > 2). We determined the optimal predictive variables (via LASSO estimation) in: model 1 (DTI variables only), model 2 (DTI plus non-DTI variables), model 3 (DTI plus ICH score). Optimism-adjusted C-statistics were calculated for each model and compared (likelihood ratio test) against the ICH score.

RESULTS

Deep grey matter MD (OR 1.04 [95% CI 1.01-1.07], p = 0.010) and white matter MD (OR 1.11 [95% CI 1.01-1.23], p = 0.044) were associated (univariate analysis) with poor outcome. Discrimination values for model 1 (0.67 [95% CI 0.52-0.83]), model 2 (0.71 [95% CI 0.57-0.85) and model 3 (0.66 [95% CI 0.52-0.82]) were all significantly higher than the ICH score (0.62 [95% CI 0.49-0.75]).

CONCLUSION

Our exploratory study suggests that whole-brain microstructural disruption measured by DTI is associated with poor 6-month functional outcome after SVD-related ICH. Whole-brain DTI metrics performed better at predicting recovery than the existing ICH score.

C1q/tumor necrosis factor-related protein-9 exerts antioxidant and anti-inflammatory effects on oxygen-glucose deprivation/reoxygenation-stimulated neurons by modulating the Akt-GSK-3β-Nrf2 cascade via AdipoR1

C1q/tumor necrosis factor-related protein-9 (CTRP9) is linked to diverse pathological conditions via the effects on cell apoptosis, inflammatory response, and oxidative stress. However, its functional relevance in ischemic brain injury is not well determined. The present work aimed to evaluate the role of CTRP9 in ischemia/reperfusion-associated neuronal injury using an in vitro model. The cultured cortical neurons were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) to simulate ischemia/reperfusion in vitro. CTRP9 level was lowered in cultured neurons exposed to OGD/R. Neurons with overexpressed CTRP9 were resistant to OGD/R-elicited injuries, including neuronal apoptosis, oxidative stress, and pro-inflammatory response. Mechanism research revealed that CTRP9 could boost the activation of the nuclear factor erythroid 2-related factor (Nrf2) pathway associated with modulation of the Akt-glycogen synthase kinase-3β (GSK-3β) axis. CTRP9 regulated the transduction of the Akt-GSK-3β-Nrf2 cascade via adiponectin receptor 1 (AdipoR1). Restraining Nrf2 could diminish CTRP9-mediated neuroprotective effects in OGD/R-injured neurons. Altogether, these results confirmed that CTRP9 exerts a protective effect on OGD/R-injured neurons by modulating Akt-GSK-3β-Nrf2 cascade via AdipoR1. This work suggests a possible link between CTRP9 and ischemic brain injury.

Role of Sirtuin 3 in Degenerative Diseases of the Central Nervous System

An NAD⁺-dependent deacetylase called Sirtuin 3 (Sirt3) is involved in the metabolic processes of the mitochondria, including energy generation, the tricarboxylic acid cycle, and oxidative stress. Sirt3 activation can slow down or prevent mitochondrial dysfunction in response to neurodegenerative disorders, demonstrating a strong neuroprotective impact. The mechanism of Sirt3 in neurodegenerative illnesses has been elucidated over time; it is essential for neuron, astrocyte, and microglial function, and its primary regulatory factors include antiapoptosis, oxidative stress, and the maintenance of metabolic homeostasis. Neurodegenerative disorders, such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS), may benefit from a thorough and in-depth investigation of Sirt3. In this review, we primarily cover Sirt3's role and its regulation in the nerve cells and the connection between Sirt3 and neurodegenerative disorders.

Elevated neutrophil-related immune-inflammatory biomarkers in acute anterior choroidal artery territory infarction with early progression

OBJECTIVE

The anterior choroidal artery territory (AChA) infarction has a high rate of progression and poor functional prognosis. The aim of the study is to search for fast and convenient biomarkers to forecast the early progression of acute AChA infarction.

METHODS

We respectively collected 51 acute AChA infarction patients, and compared the laboratorial index between early progressive and non-progressive acute AChA infarction patients. The receiver-operating characteristics curve (ROC) analysis was used to determine the discriminant efficacy of indicators that had statistical significance.

RESULTS

The white blood cell, neutrophil, monocyte, white blood cell to high-density lipoprotein cholesterol ratio, neutrophil to high-density lipoprotein cholesterol ratio (NHR), monocyte to high-density lipoprotein cholesterol ratio, monocyte to lymphocyte ratio, neutrophil to lymphocyte ratio (NLR), and hypersensitive C-reaction protein in acute AChA infarction are significantly higher than healthy controls (P < 0.05). The NHR (P = 0.020) and NLR (P = 0.006) are remarkably higher in acute AChA infarction patients with early progression than non-progression. The area under the ROC curve of NHR, NLR, the combine of NHR and NLR are 0.689 (P = 0.011), 0.723 (P = 0.003), 0.751 (P < 0.001), respectively. But there are no significant differences in efficiency between NHR and NLR and their combined marker in predicting progression (P > 0.05).

CONCLUSION

NHR and NLR may be significant predictors of early progressive patients with acute AChA infarction, and the combination of NHR and NLR could be a preferable prognostic marker for AChA infarction with early progressive course in acute stage.

Intranasal Delivery of Gene-Edited Microglial Exosomes Improves Neurological Outcomes after Intracerebral Hemorrhage by Regulating Neuroinflammation

Neural inflammatory response is a crucial pathological change in intracerebral hemorrhage (ICH) which accelerates the formation of perihematomal edema and aggravates neural cell death. Although surgical and drug treatments for ICH have advanced rapidly in recent years, therapeutic strategies that target and control neuroinflammation are still limited. Exosomes are important carriers for information transfer among cells. They have also been regarded as a promising therapeutic tool in translational medicine, with low immunogenicity, high penetration through the blood-brain barrier, and ease of modification. In our previous research, we have found that exogenous administration of miRNA-124-overexpressed microglial exosomes (Exo-124) are effective in improving post-injury cognitive impairment. From this, we evaluated the potential therapeutic effects of miRNA-124-enriched microglial exosomes on the ICH mice in the present study. We found that the gene-edited exosomes could attenuate neuro-deficits and brain edema, improve blood-brain barrier integrity, and reduce neural cell death. Moreover, the protective effect of Exo-124 was abolished in mice depleted of Gr-1⁺ myeloid cells. It suggested that the exosomes exerted their functions by limiting the infiltration of leukocyte into the brain, thus controlling neuroinflammation following the onset of ICH. In conclusion, our findings provided a promising therapeutic strategy for improving neuroinflammation in ICH. It also opens a new avenue for intranasal delivery of exosome therapy using miRNA-edited microglial exosomes.

Post-ischemic inflammatory response in the brain: Targeting immune cell in ischemic stroke therapy

An ischemic stroke occurs when the blood supply is obstructed to the vascular basin, causing the death of nerve cells and forming the ischemic core. Subsequently, the brain enters the stage of reconstruction and repair. The whole process includes cellular brain damage, inflammatory reaction, blood–brain barrier destruction, and nerve repair. During this process, the proportion and function of neurons, immune cells, glial cells, endothelial cells, and other cells change. Identifying potential differences in gene expression between cell types or heterogeneity between cells of the same type helps to understand the cellular changes that occur in the brain and the context of disease. The recent emergence of single-cell sequencing technology has promoted the exploration of single-cell diversity and the elucidation of the molecular mechanism of ischemic stroke, thus providing new ideas and directions for the diagnosis and clinical treatment of ischemic stroke.

Brain and blood single-cell transcriptomics in acute and subacute phases after experimental stroke

Cerebral ischemia triggers a powerful inflammatory reaction involving both peripheral leukocytes and brain resident cells. Recent evidence indicates that their differentiation into a variety of functional phenotypes contributes to both tissue injury and repair. However, the temporal dynamics and diversity of post-stroke immune cell subsets remain poorly understood. To address these limitations, we performed a longitudinal single-cell transcriptomic study of both brain and mouse blood to obtain a composite picture of brain-infiltrating leukocytes, circulating leukocytes, microglia and endothelium diversity over the ischemic/reperfusion time. Brain cells and blood leukocytes isolated from mice 2 or 14 days after transient middle cerebral artery occlusion or sham surgery were purified by FACS sorting and processed for droplet-based single-cell transcriptomics. The analysis revealed a strong divergence of post-ischemic microglia, macrophages, and neutrophils over time, while such diversity was less evident in dendritic cells, B, T and NK cells. Conversely, brain endothelial cells and brain associated-macrophages showed altered transcriptomic signatures at 2 days post-stroke, but low divergence from sham at day 14. Pseudotime trajectory inference predicted the in-situ longitudinal progression of monocyte-derived macrophages from their blood precursors into day 2 and day 14 phenotypes, while microglia phenotypes at these two time points were not connected. In contrast to monocyte-derived macrophages, neutrophils were predicted to be continuously de-novo recruited from the blood. Brain single-cell transcriptomics from both female and male aged mice did not show major changes in respect to young mice, but aged and young brains differed in their immune cell composition. Furthermore, blood leukocyte analysis also revealed altered transcriptomes after stroke. However, brain-infiltrating leukocytes displayed higher transcriptomic divergence than their circulating counterparts, indicating that phenotypic diversification into cellular subsets occurs within the brain in the early and the recovery phase of ischemic stroke. In addition, this resource report contains a searchable database https://anratherlab.shinyapps.io/strokevis/ to allow user-friendly access to our data. The StrokeVis tool constitutes a comprehensive gene expression atlas that can be interrogated at the gene and cell type level to explore the transcriptional changes of endothelial and immune cell subsets from mouse brain and blood after stroke.

Lactate modulates microglial inflammatory responses after oxygen-glucose deprivation through HIF-1α-mediated inhibition of NF-κB

Metabolic adaption drives microglial inflammatory responses, and lactate shapes immunological and inflammatory states. However, whether lactate was involved in the regulation of microglial inflammatory responses after cerebral ischemia remains unclear. In this study, the expression of iNOS, arginase-1, phosphorylated NF-κB p65 and IκB-α, and HIF-1α in BV2 cells after oxygen-glucose deprivation (OGD) were detected by western blotting and immunofluorescence. The mRNA levels of microglial responsive markers and inflammatory factors were assessed by real-time-qPCR. The effect of lactate-treated BV2 cells on the survival of primary neurons was observed using transwell co-culture. The results showed that the protein levels of iNOS and arginase-1, the ratio of mRNA levels of iNOS/CD206, CD86/Ym1, IL-6/IL-10, TNF-α/IL-10 and the mRNA levels of IL-6 and TNF-α, as well as the protein levels of phosphorylated NF-κB p65 and IκB-α, were increased after OGD. Lactate treatment inhibited the OGD-induced increase in the protein levels of iNOS, phosphorylated NF-κB p65 and IκB-α, as well as iNOS/CD206, CD86/Ym1, IL-6/IL-10, TNF-α/IL-10, IL-6 and TNF-α mRNA levels in BV2 cells, while promoted arginase-1 protein expression as well as IL-10 and TGF-β mRNA level. Interestingly, lactate activated HIF-1α and the HIF-1α inhibitor YC-1 reversed the effect of lactate on levels of microglial responsive markers and phosphorylated NF-κB p65 and IκB-α in BV2 cells. Moreover, knockdown of HIF-1α by lentivirus-delivered shRNA also reversed the effect of lactate on phosphorylated NF-κB p65 and IκB-α in BV2 cells after OGD. Finally, and importantly, lactate-treated BV2 microglia increased the viability and decreased the apoptosis of neurons after OGD. These findings revealed that lactate inhibited NF-κB pathway and skewed BV2 microglia toward the protective response through activation of HIF-1α after OGD, thereby improving neuronal survival.

Construction of a Nomogram Prediction Model for Prognosis in Patients with Large Artery Occlusion-Acute Ischemic Stroke

BACKGROUND

Patients with large artery occlusion-acute ischemic stroke (LAO-AIS) can experience adverse outcomes, such as brain herniation due to complications. This study aimed to construct a nomogram prediction model for prognosis in patients with LAO-AIS in order to maximize the benefits for clinical patients.

METHODS

Retrospective analysis of 243 patients with LAO-AIS from January 2019 to January 2022 with medical history data and blood examination at admission. Univariate and multivariate analyses were conducted through binary logistic regression equation analysis, and a nomogram prediction model was constructed.

RESULTS

Results of this study showed that hyperlipidemia (odds ratio [OR] = 2.849, 95% confidence interval [CI] = 1.100-7.375, P = 0.031), right cerebral infarction (OR = 2.144, 95% CI = 1.106-4.156, P = 0.024), D-Dimer>500 ng/mL (OR = 2.891, 95% CI = 1.398-5.980, P = 0.004), and neutrophil-lymphocyte ratio >7.8 (OR = 2.149, 95% CI = 1.093-4.225, P = 0.027) were independent risk factors for poor early prognosis in patients with LAO-AIS. In addition, hypertension (OR = 1.947, 95% CI = 1.114-3.405, P = 0.019), hyperlipidemia (OR = 2.594, 95% CI = 1.281-5.252, P = 0.008), smoking (OR = 2.414, 95% CI = 1.368-4.261, P = 0.002), D-dimer>500 ng/mL (OR = 3.170, 95% CI = 1.533-6.553, P = 0.002), and neutrophil-lymphocyte ratio >7.8 (OR = 2.144, 95% CI = 1.231-3.735, P = 0.007) were independent risk factors for poor long-term prognosis. The early prognosis nomogram receiver operating characteristic curve area under the curve value was 0.688 for the training set and 0.805 for the validation set, which was highly differentiated. The mean error was 0.025 for the training set calibration curve and 0.016 for the validation set calibration curve. Both the training and validation set decision curve analyses indicated that the clinical benefit of the nomogram was significant. The long-term prognosis nomogram receiver operating characteristic curve area under the curve values was 0.697 for the training set and 0.735 for the validation set, showing high differentiation. The mean error was 0.041 for the training set calibration curve and 0.021 for the validation set calibration curve. Both of the training and validation set decision curve analyses demonstrated a substantial clinical benefit of the nomogram.

CONCLUSIONS

The nomogram prediction model based on admission history data and blood examination are easy-to-use tools that provide an accurate individualized prediction for patients with LAO-AIS and can assist in early clinical decisions and in obtaining an early prognosis.

iPSC-sEVs alleviate microglia senescence to protect against ischemic stroke in aged mice

The polarization of microglia plays an important role in the outcome of ischemic stroke (IS). In the aged population, senescent microglia show a predominant pro-inflammatory phenotype, which leads to worse outcomes in aged ischemic stroke compared to young ischemic stroke. Recent research demonstrated that inducible pluripotent stem cell-derived small extracellular vesicles (iPSC-sEVs) possess the significant anti-ageing ability. We hypothesized that iPSC-sEVs could alleviate microglia senescence to regulate microglia polarization in aged ischemic stroke. In this study, we showed that treatment with iPSC-sEVs significantly alleviated microglia senescence as indicated by the decreased senescence-associated proteins including P16, P21, P53, and γ-H2AX as well as the activity of SA-β-gal, and inhibited pro-inflammatory activation of microglia both in vivo and in vitro. Furthermore, iPSC-sEVs shifted microglia from pro-inflammatory phenotype to anti-inflammatory phenotype, which reduced the apoptosis of neurons, and improved the outcome of aged stroke mice. Mechanism studies showed that iPSC-sEVs reversed the loss of Rictor and downstream p-AKT (s473) in senescent microglia, which was involved in the senescence and pro-inflammatory phenotype regulation of microglia. Inhibition of Rictor abolished the iPSC-sEVs-afforded phosphorylation of AKT and alleviation of inflammation of senescent microglia. Proteomics results indicated that iPSC-sEVs carried transforming growth factor-β1 (TGF-β1) to upregulate Rictor and p-AKT in senescent microglia, which could be hindered by blocking TGF-β1. Taken together, our work demonstrates iPSC-sEVs reverse the senescent characteristic of microglia in aged brains and therefore improve the outcome after stroke, at least, via delivering TGF-β1 to upregulate Rictor and p-AKT. Our data suggest that iPSC-sEVs might be a novelty therapeutic method for aged ischemic stroke and other diseases involving senescent microglia.