Systemic inflammation as a therapeutic target in acute ischemic stroke

Neuroprotection of Human Umbilical Cord-Derived Mesenchymal Stem Cells (hUC-MSCs) in Alleviating Ischemic Stroke-Induced Brain Injury by Regulating Inflammation and Oxidative Stress

Brain injury caused by stroke has a high rate of mortality and remains a major medical challenge worldwide. In recent years, there has been significant attention given to the use of human Umbilical cord-derived Mesenchymal Stem Cells (hUC-MSCs) for the treatment of stroke in different adult and neonate animal models of stroke. However, using hUC-MSCs by systemic administration to treat ischemic stroke has not been investigated sufficiently. In this study, we conducted various experiments to explore the neuroprotection of hUC-MSCs in rats. Our findings demonstrate that an intravenous injection of a high dose of hUC-MSCs at 2 × 10^7 cells/kg markedly ameliorated brain injury resulting from ischemic stroke. This improvement was observed one day after inducing transient middle cerebral artery occlusion (MCAO) and subsequent reperfusion in rats. Notably, the efficacy of this single administration of hUC-MSCs surpassed that of edaravone, even when the latter was used continuously over three days. Mechanistically, secretory factors derived from hUC-MSCs, such as HGF, BDNF, and TNFR1, ameliorated the levels of MDA and T-SOD to regulate oxidative stress. In particular, TNFR1 also improved the expression of NQO-1 and HO-1, important proteins associated with oxidative stress. More importantly, TNFR1 played a significant role in reducing inflammation by modulating IL-6 levels in the blood. Furthermore, TNFR1 was observed to influence the permeability of the blood-brain barrier (BBB) as demonstrated in the evan's blue experiment and protein expression of ZO-1. This study represented a breakthrough in traditional methods and provided a novel strategy for clinical medication and trials.

IL-6 and stroke recurrence in ischemic stroke

Objective: This study aimed to evaluate the predictive value of IL-6 for stroke recurrence in acute ischemic stroke.Methods: Patients who were admitted within 48 h of onset were included. At 3-month, stroke recurrence was assessed. IL-6 levels were measured in serum samples taken upon admission.Results: Out of the 305 patients, 47 (15.4%) experienced a stroke recurrence. The risk of stroke recurrence increased by 8% (OR: 1.08; 95% CI: 1.04-1.11; p < 0.001) for every 1 pg/ml increase in IL-6 serum level, both in unadjusted and adjusted analyses (6%; OR: 1.06; 95% CI: 1.02-1.10; p = 0.001).Conclusion: The study supports the usefulness of IL-6 as a predictive biomarker for stroke recurrence after acute ischemic stroke.

Synthesis and bioactivity evaluation of glycosylated resveratrol derivatives as antioxidative neuroprotection agents against cerebral Ischemia-Reperfusion injury

Resveratrol (Res) has long been discovered to have antioxidant effects to prevent such as oxidation, inflammation, neurodegeneration and age-related diseases. However, its poor water solubility, low bioavailability and instability have become a barrier to its pharmaceutical application. In order to improve the neuroprotective effects and develop more potential usage of Res, three Res derivatives containing one or two glucose groups, i.e., Res-Glu1, Res-Glu2 and Res-Glu3, were designed and synthesized through click reaction. Res-Glu1, Res-Glu2 and Res-Glu3 were tested being better water solubility and stability compared to Res. Res derivatives reduced •OH radicals-induced DNA damage. PC12 assays indicated that glucosylated Res derivatives could alleviate H2O2-induced neurotoxicity and reduce intracellular ROS generation, demonstrating their neuroprotective effects. In addition, Res derivatives enhanced the protective effects on cerebral ischemia-reperfusion injury in rats. Res-Glu3 displayed the best neuroprotective effects among the three derivatives.

Innate immune memory after brain injury drives inflammatory cardiac dysfunction

The medical burden of stroke extends beyond the brain injury itself and is largely determined by chronic comorbidities that develop secondarily. We hypothesized that these comorbidities might share a common immunological cause, yet chronic effects post-stroke on systemic immunity are underexplored. Here, we identify myeloid innate immune memory as a cause of remote organ dysfunction after stroke. Single-cell sequencing revealed persistent pro-inflammatory changes in monocytes/macrophages in multiple organs up to 3 months after brain injury, notably in the heart, leading to cardiac fibrosis and dysfunction in both mice and stroke patients. IL-1β was identified as a key driver of epigenetic changes in innate immune memory. These changes could be transplanted to naive mice, inducing cardiac dysfunction. By neutralizing post-stroke IL-1β or blocking pro-inflammatory monocyte trafficking with a CCR2/5 inhibitor, we prevented post-stroke cardiac dysfunction. Such immune-targeted therapies could potentially prevent various IL-1β-mediated comorbidities, offering a framework for secondary prevention immunotherapy.

Multistrain Probiotics with Fructooligosaccharides Improve Middle Cerebral Artery Occlusion-Driven Neurological Deficits by Revamping Microbiota-Gut-Brain Axis

Recent burgeoning literature unveils the importance of gut microbiota in the neuropathology of post-stroke brain injury and recovery. Indeed, ingestion of prebiotics/probiotics imparts positive effects on post-stroke brain injury, neuroinflammation, gut dysbiosis, and intestinal integrity. However, information on the disease-specific preference of selective prebiotics/probiotics/synbiotics and their underlying mechanism is yet elusive. Herein, we examined the effect of a new synbiotic formulation containing multistrain probiotics (Lactobacillus reuteri UBLRu-87, Lactobacillus plantarum UBLP-40, Lactobacillus rhamnosus UBLR-58, Lactobacillus salivarius UBLS-22, and Bifidobacterium breve UBBr-01), and prebiotic fructooligosaccharides using a middle cerebral artery occlusion (MCAO) model of cerebral ischemia in female and male rats. Three weeks pre-MCAO administration of synbiotic rescinded the MCAO-induced sensorimotor and motor deficits on day 3 post-stroke in rotarod, foot-fault, adhesive removal, and paw whisker test. We also observed a decrease in infarct volume and neuronal death in the ipsilateral hemisphere of synbiotic-treated MCAO rats. The synbiotic treatment also reversed the elevated levels/mRNA expression of the glial fibrillary acidic protein (GFAP), NeuN, IL-1β, TNF-α, IL-6, matrix metalloproteinase-9, and caspase-3 and decreased levels of occludin and zonula occludens-1 in MCAO rats. 16S rRNA gene-sequencing data of intestinal contents indicated an increase in genus/species of Prevotella (Prevotella copri), Lactobacillus (Lactobacillus reuteri), Roseburia, Allobaculum, and Faecalibacterium prausnitzii, and decreased abundance of Helicobacter, Desulfovibrio, and Akkermansia (Akkermansia muciniphila) in synbiotic-treated rats compared to the MCAO surgery group. These findings confer the potential benefits of our novel synbiotic preparation for MCAO-induced neurological dysfunctions by reshaping the gut-brain-axis mediators in rats.

Cell-Free Supernatant of Lactobacillus rhamnosus and Bifidobacterium breve Ameliorates Ischemic Stroke-Generated Neurological Deficits in Rats

The beneficial effects of probiotics, postbiotics, and paraprobiotics have already been registered in managing ischemic stroke-generated neuroinflammation and gut dysbiosis. Herein, we examined the impact of cell-free supernatant (CFS) obtained from probiotics (Lactobacillus rhamnosus UBLR-58 and Bifidobacterium breve UBBr-01) in a rat transient middle cerebral artery occlusion (MCAO) model of focal cerebral injury. Pre-MCAO supplementation of probiotics (2 × 109 CFU/mL) for 21 days or CFS (1 mL/rat) for 7 days protect the MCAO-induced somatosensory and motor impairments recorded at 24 h and 72 h after reperfusion in foot-fault, rotarod, adhesive removal, and vibrissae-evoked forelimb placing tests. We also noted the reduced infarct area and neuronal degradation in the right hemisphere of probiotics- and CFS-recipient MCAO-operated animals. Moreover, MCAO-induced altered concentrations of glial-fibrillary acidic protein, NeuN, zonula occludens-1 (ZO-1), TLR4, IL-1β, IL-6, and TNF-α, as well as matrix metalloproteinase-9 (MMP9) were reversed in the treatment groups. Probiotics and CFS treatment ameliorated the elevated levels of IL-6, IL-1β, and MMP9 in the blood plasma of rats. The disrupted microbial phyla, Firmicutes-to-Bacteroides ratio, villi/crypt ratio, and decreased mucin-producing goblet cells, ZO-1, and occludin in the colon of MCAO-operated rats were recovered following probiotics and CFS treatment. NMR characterization of CFS and rat blood plasma revealed the presence of several important bacterial metabolites. These findings suggest that the CFS obtained from Lactobacillus rhamnosus UBLR-58 and Bifidobacterium breve UBBr-01 has the propensity to improve MCAO-generated neurological dysfunctions in rats by dampening neuroinflammation and modulating the gut-brain axis modulators.

Red blood cell distribution width as a predictor of mortality and poor functional outcome after acute ischemic stroke: a meta-analysis and meta-regression

BACKGROUND

This study aimed to review evidence on the ability of red cell distribution width (RDW) to predict mortality and poor functional outcomes after acute ischemic stroke (AIS).

METHODS

Databases of PubMed, CENTRAL, Scopus, Embase, and Web of Science were searched online from inception to 25th Jul 2023 for all studies reporting the association between RDW and outcomes as adjusted ratios. A random-effects meta-analysis was done. Meta-regression was conducted using multiple moderators.

RESULTS

15 studies with 14,968 patients were included. Meta-analysis found that RDW, both as a categorical variable (OR: 2.10 95% CI: 1.74, 2.55 I2 = 42%) and continuous variable OR: 1.16 95% CI: 1.05, 1.28 I2 = 64%) was a significant predictor of mortality after AIS. Age and number of hypertensives were found to be significant moderators in the meta-regression. Also, high RDW, as a categorical variable (OR: 1.68 95% CI: 1.20, 2.35 I2 = 84%), was associated with significantly higher odds of poor functional outcomes after AIS, but not as a continuous variable (OR: 1.07 95% CI: 0.99, 1.16 I2 = 61%). Meta-regression showed that the association was stronger in small sample-sized studies.

CONCLUSION

RDW can be a useful, readily available, and cost-effective biomarker to rapidly stratify AIS patients at risk of poor outcomes. High RDW was consistently associated with an increased risk of mortality after AIS, however, its ability to predict poor functional outcomes needs to be verified by further studies.

Oxyberberine protects middle cerebral artery occlusion triggered cerebral injury through TLR4/NLRP3 pathway in rats

Cerebral ischemia is a life-threatening health concern that leads to severe neurological complications and fatalities worldwide. Although timely intervention with clot-removing agents curtails serious post-stroke neurological dysfunctions, no effective neuroprotective intervention is available for addressing post-recanalization neuroinflammation. Herein, for the first time we studied the effect of oxyberberine (OBB), a derivative of berberine, on transient middle cerebral artery occlusion (MCAO)-generated neurological consequences in Sprague-Dawley rats. The MCAO-operated rats exhibited significant somatosensory and sensorimotor dysfunctions in adhesive removal, foot fault, paw whisker, and rotarod assays at 1 and 3 days post-surgery. These MCAO-generated neurological deficits were prevented in OBB-treated (50 and 100 mg/kg) rats, and also coincided with a smaller infarct area (in 2,3,5-triphenyl tetrazolium chloride staining) and decreased neuronal death (in cresyl violet staining) in the ipsilateral hemisphere of these animals. The immunostaining of neuronal nuclear protein (NeuN) and glial-fibrillary acidic protein (GFAP) also echoes the neuroprotective nature of OBB. The increased expression of neuroinflammatory and blood-brain barrier tight junction proteins like toll-like receptor 4 (TLR4), TRAF-6, nuclear factor kappa B (NF-κB), pNF-κB, nNOS, ASC, and IKBα in the ipsilateral part of MCAO-operated rats were restored to normal following OBB treatment. We also observed the decline in plasma levels/mRNA transcription of TNF-α, IL-1β, NLRP3, IL-6, and matrix metalloproteinase-9 and increased expression of occludin and claudin in OBB-treated rats. These outcomes imply that OBB may prevent the MCAO-induced neurological consequences and neuroinflammation by interfering with TLR4 and NLRP3 signaling in rats.

Feasibility and Safety of Sildenafil to Repair Brain Injury Secondary to Birth Asphyxia (SANE-01): A Randomized, Double-blind, Placebo-controlled Phase Ib Clinical Trial

OBJECTIVE

To test feasibility and safety of administering sildenafil in neonates with neonatal encephalopathy (NE), developing brain injury despite therapeutic hypothermia (TH).

STUDY DESIGN

We performed a randomized, double-blind, placebo-controlled phase Ib clinical trial between 2016 and 2019 in neonates with moderate or severe NE, displaying brain injury on day-2 magnetic resonance imaging (MRI) despite TH. Neonates were randomized (2:1) to 7-day sildenafil or placebo (2 mg/kg/dose enterally every 12 hours, 14 doses). Outcomes included feasibility and safety (primary outcomes), pharmacokinetics (secondary), and day-30 neuroimaging and 18-month neurodevelopment assessments (exploratory).

RESULTS

Of the 24 enrolled neonates, 8 were randomized to sildenafil and 3 to placebo. A mild decrease in blood pressure was reported in 2 of the 8 neonates after initial dose, but not with subsequent doses. Sildenafil plasma steady-state concentration was rapidly reached, but decreased after TH discontinuation. Twelve percent of neonates (1/8) neonates died in the sildenafil group and 0% (0/3) in the placebo group. Among surviving neonates, partial recovery of injury, fewer cystic lesions, and less brain volume loss on day-30 magnetic resonance imaging were noted in 71% (5/7) of the sildenafil group and in 0% (0/3) of the placebo group. The rate of death or survival to 18 months with severe neurodevelopmental impairment was 57% (4/7) in the sildenafil group and 100% (3/3) in the placebo group.

CONCLUSIONS

Sildenafil was safe and well-absorbed in neonates with NE treated with TH. Optimal dosing needs to be established. Evaluation of a larger number of neonates through subsequent phases II and III trials is required to establish efficacy.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.govNCT02812433.

Vagus nerve stimulation as immunomodulatory therapy for stroke: A comprehensive review

Stroke is a devastating cerebrovascular pathology with high morbidity and mortality. Inflammation plays a central role in the pathophysiology of stroke. Vagus nerve stimulation (VNS) is a promising immunomodulatory method that has shown positive effects in stroke treatment, including neuroprotection, anti-apoptosis, anti-inflammation, antioxidation, reduced infarct volume, improved neurological scores, and promotion of M2 microglial polarization. In this review, we summarize the current knowledge about the vagus nerve's immunomodulatory effects through the cholinergic anti-inflammatory pathway (CAP) and provide a comprehensive assessment of the available experimental literature focusing on the use of VNS in stroke treatment.

Mesencephalic astrocyte-derived neurotrophic factor (MANF) alleviates cerebral ischemia/reperfusion injury in mice by regulating microglia polarization via A20/NF-κB pathway

Microglia, resident brain immune cells, is critical in inflammation, apoptosis, neurogenesis and neurological recovery during cerebral ischemia/reperfusion (I/R) injury. Mesencephalic astrocyte-derived neurotrophic factor (MANF), a novel identified endoplasmic reticulum stress-inducible neurotrophic factor, can alleviate I/R injury by reducing the inflammatory reaction, but its specific regulatory mechanism on microglia after ischemic stroke has not been fully clarified. To mimic the process of ischemia/reperfusion in vivo and in vitro, middle cerebral artery occlusion/reperfusion (MCAO/R) was induced in C57BL/6J mice and oxygen glucose deprivation/reoxygenation (OGD/R) model was established in BV-2 cells. Moreover, MANF small interfering RNA (siRNA) was used to silence the expression of endogenous MANF, while recombination human MANF protein (rhMANF) acted as an exogenous supplement. Seventy-two hours after MCAO/R, 2,3,5-triphenyltetrazolium staining, neurological scores, brain water content, immunohistochemical staining, immunofluorescent staining, flow cytometry, hematoxylin and eosin staining, quantitative real-time PCR and western blot are applied to evaluate the protective effect and possible mechanism of MANF on cerebral I/R injury. In vitro, cell viability, inflammatory cytokines and the expression of MANF, A20, NF-κB and the markers of microglia were analyzed. The results showed that MANF decreased brain infarct volume, neurological scores, and brain water content. In addition, MANF promoted the polarization of microglia to an anti-inflammatory phenotype both in vivo and in vitro, which are related to A20/NF-κB pathway. In summary, MANF may offer novel therapeutic approaches for ischemic stroke in the process of microglia polarization.

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.

Reduced ex vivo TNFα synthesis upon whole blood stimulation with endotoxin predicts post-stroke fatigue

OBJECTIVE

Fatigue is a common, debilitating syndrome after stroke. Peripheral inflammation plays a role in the pathogenesis of fatigue of different origin, but its contribution to post-stroke fatigue (PSF) remains unclear. We aimed to determine if there is any association between ex vivo synthesized and circulating cytokines, and risk of PSF.

METHODS

We included 174 patients with ischemic stroke. We stimulated in vitro blood taken on day 3 after stroke with endotoxin. We measured ex vivo released (TNFα, IP-10, IL-1β, IL-6, IL-8, IL-10, IL-12p70) and plasma (TNFα, IL-6, sIL-6R, IL-1Ra) cytokines. We assessed fatigue at month 3 using Fatigue Severity Scale (FSS). We used logistic regression to assess the relationship between cytokines and fatigue scores.

RESULTS

Compared with patients with lower fatigue at month 3 (FSS < 36), patients with higher fatigue (FSS ≥ 36) had lower endotoxin-stimulated TNFα release after 24 h (median: 429 vs 581 pg/mL, P = 0.05). Plasma TNFα tended to be higher in patients who developed fatigue (median: 0.8 vs 0.6 pg/mL, P = 0.06). Other cytokines did not differ between groups. After adjusting for pre-stroke fatigue and depressive symptoms, TNFα release <559.7 pg/mL after 24 h was associated with an increased risk of PSF (OR: 2.61, 95%CI: 1.22-5.57, P = 0.01). Plasma TNFα >0.76 pg/mL was associated with higher risk of PSF in univariable (OR: 2.41, 95%CI: 1.13-5.15, P = 0.02), but not multivariable analysis (OR: 2.41, 95%CI: 0.96-6.00, P = 0.06).

CONCLUSION

Reduced ex vivo TNFα synthesis upon whole blood stimulation with endotoxin in the acute phase of stroke predicted PSF.

Clinical role of vitamin D, vitamin B12, folate levels and hematological parameters in patients with sudden sensorineural hearing loss

BACKGROUND

Sudden sensorineural hearing loss (SSNHL), which is frequently observed in otolaryngology clinics, is characterized by sudden onset hearing loss that can develop within hours or days. Its etiology is still not fully understood.

AIMS/OBJECTIVES

This research aims to identify prognostic biomarkers that can be utilized to assess the progress of SSNHL as well as circumstances that may predispose individuals to the disease.

MATERIALS AND METHODS

Between 1 January 2019 and 1 October 2020, patients diagnosed with SSNHL in our clinic and a control group consisting of healthy people were examined retrospectively. The files of the groups were examined and the levels of hemoglobin, Neutrophil-Lymphocyte Ratio (NLR), ferritin, iron, iron binding capacity (UIBC), vitamin D, vitamin B12, folate were statistically compared with the control group. In addition, the effect of the parameters studied in the patient group on the degree of recovery was examined.

RESULTS

There was no statistically significant difference between the groups in terms of mean age and gender distribution (p > .05). NLR level of the patient group was higher than the control group (p < .05). Vitamin D level of the patient group was lower than the control group (p < .05). NLR and vitamin D levels had no effect on the degree of recovery (p > .05). There was no significant difference between the groups in terms of other parameters (p > .05).

CONCLUSIONS AND SIGNIFICANCE

We think that our study can be a guide for adding vitamin D as a routine laboratory test in patients with SSNHL. In addition, we think that NLR value can be used as a marker in patients with SSNHL. It is recommended to investigate the role of vitamin D supplementation in better and faster response in these patients.

Beneficial effects of buspirone in endothelin-1 induced stroke cachexia in rats

Stroke cachexia is associated with prolonged inflammation, muscle loss, poor prognosis, and early death of stroke patients. No particular treatment is available to cure the symptoms or disease. The present study aimed to evaluate the effect of a 5-HT1a agonist, buspirone on stroke cachexia. Wistar rats were injected with endothelin-1 to the bregma region of the brain to induce ischemic stroke followed by induction of cachexia after 4 days. Treatment with buspirone (3 mg/kg p.o) was given for 4 weeks after confirmation of cachexia in animals. Disease control animals exhibited decrease in wire hanging time and increase in foot fault numbers compared to normal animals. Disease control animals also showed weight loss, decrease in food intake, increased serum glucose and lipid profile along with high serum levels of inflammatory cytokines-TNF-α, IL-6 and decrease in weight of skeletal muscle and adipose tissues. Treatment with buspirone improves behavioural parameters along with increases food intake and body weight, decreased inflammatory cytokines IL-6 and TNF-α and serum glucose levels with increase in lipid profile. Buspirone also increased the weight of adipose tissue and maintain the skeletal muscle architecture and function as depicted in histopathological studies. Our study suggests that buspirone produces beneficial role in stroke cachexia by increasing body weight, food intake and adipose tissue depots by activating on 5-HT receptors. Buspirone decreases inflammatory markers in stroke cachexia although mechanism behind it was not fully understood. Buspirone decreases circulating blood glucose by stimulating glucose uptake in skeletal muscle via 5-HT receptors and maintained lipid profile. Buspirone was found to be effective in ameliorating cachectic conditions in stroke.

Inflammatory markers and the risk of idiopathic sudden sensorineural hearing loss: A Mendelian randomization study

Background

Observational studies suggest that inflammatory markers may increase the risk of idiopathic sudden sensorineural hearing loss (ISSHL). However, the causal relationship between the two has not been established. We sought to assess the possible causal effect between several genetically predicted inflammatory markers and ISSHL by Mendelian random (MR) analysis.

Methods

We extracted single nucleotide polymorphisms (SNPs) associated with C-reactive protein (CRP), Tumor necrosis factor-α (TNF-α), and fibrinogen from abstract data from the European Individual Large genome-wide association studies (GWAS). Genetic data for ISSHL were obtained from the FinnGen study (n = 196,592). Effect estimates were assessed using inverse variance weighting (IVW) as the primary method. Sensitivity analyses were performed using weighted median, MR-Egger, and MR-PRESSO to evaluate heterogeneity and pleiotropy.

Results

In the random-effects IVW approach, there was a significant causal relationship between genetic susceptibility to CRP levels and ISSHL (OR = 1.23, 95% CI = 1.02-1.49, P = 0.03). In contrast, genetic TNF-α and fibrinogen were not risked factors for ISSHL (OR = 1.14, 95% CI = 0.88-1.49, P = 0.30; OR = 0.74, 95% CI = 0.07-7.96, P = 0.30; OR = 1.05, 95% CI = 0.88-1.25, P = 0.59). All the above results were consistent after validation by different Mendelian randomization methods and sensitivity analyses.

Conclusion

This Mendelian randomization study provides causal evidence that CRP is a risk factor for ISSHL, while TNF-α and fibrinogen do not increase the risk for ISSHL Introduction.

[Multifactorial analysis of the degree of hearing loss and outcome in patients with sudden hearing loss]

Objective:To investigate the relationship between the severity and curative effect of hearing loss and clinical indicators in patients with sudden hearing loss （SHL）. Methods:The Spearman correlation coefficient was used to analyze the correlation between the efficacy of SHL and clinical indicators.A total of two hundred and seventy-three patients with SHL were selected and divided into three quantile groups according to the average hearing threshold of the the involved ear frequency of the first pure tone audiometry at admission. Univariate and multivariate ordered logistic regression were used to evaluate the relationship between initial hearing level and clinical indicators of SHL patients. The Spearman correlation coefficient was used to analyze the correlation between efficacy of SHL and clinical indicators. Results:Compared with patients with lower hearing loss （≤50 dB HL），patients with higher hearing loss （>50 dB HL） had higher Neutrophil, Monocyte, Triglycerides, Hemoglobin, Fibrinogen, Glucose, Neutrophil/high-density lipoprotein cholesterol ratio （NHR）, Monocyte/high-density lipoprotein cholesterol ratio, Monocyte/lymphocyte cell ratio, age, dizziness, and lower Platelet/ lymphocyte cell ratio and High-density lipoprotein cholesterol, and poor final hearing threshold.Multivariate logistic regression showed that NHR and age were independent risk factors for initial hearing loss in SHL patients.And the NHR, Neutrophil/lymphocyte cell ratio （NLR）, course of disease, type of hearing curve, and final hearing threshold were significantly negatively correlated with curative effect. Conclusion:SHL patients with higher NHR and NLR values, the longer time from onset to visit, and the more severe hearing loss had worse efficacy.However, SHL patients with higher NHR and age values had greater initial hearing loss,the degree of hearing loss and curative effect are different in SHL patients with different types of hearing threshold curve and age.

Network pharmacology study on the potential effect mechanism of Chuanzhi Tongluo Capsule in the treatment of cerebral infarction

BACKGROUND

Chuanxiong Tongluo capsules have been widely used to treat recovered stroke and cerebral infarction, but their specific therapeutic mechanism is not well understood.

METHODS

This study aims to investigate the mechanism of action for Chuanzhi Tongluo capsule on cerebral infarction based on a network pharmacology approach. The TCMSP platform collected the chemical composition of Chuanzhi Tongluo capsules. Its potential targets were predicted by Swiss target prediction and standardized using the Uniprot database for gene normalization. Meanwhile, the OMIM, Genecards, and TTD databases were used to obtain the targets related to cerebral infarction. The standard targets of Chuanzhi Tongluo capsule and cerebral infarction were uploaded to the STRING database to construct protein-protein interaction networks. Topological methods analyzed the key targets and components in the drug-component-disease-target network. Gene ontology function and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis of the shared targets were performed using the DAVID database.

RESULTS

A total of 105 active ingredients and 427 targets were associated with Chuanzhi Tongluo capsule, and there were 3055 targets related to cerebral infarction disease and 240 common targets between the two keywords. The key targets included INS, ALB, IL-6, VEGFA, TNF, and TP53. The conduction pathways involved include the calcium signaling pathway, cAMP signaling pathway, cGMP-PKG signaling pathway, and TNF signaling pathway.

CONCLUSION

The active ingredients in Chuanzhi Tongluo capsule may participate in the therapeutic process of cerebral infarction by regulating the calcium, cAMP, cGMP-PKG, and TNF signaling pathway through critical targets such as INS, ALB, IL-6, VEGFA, TNF, and TP53.

Bone marrow mesenchymal stem cell-derived exosomes carrying long noncoding RNA ZFAS1 alleviate oxidative stress and inflammation in ischemic stroke by inhibiting microRNA-15a-5p

BACKGROUND/AIM

Bone marrow mesenchymal stem cell (BMSC)-derived exosomes can prevent oxidative stress and inflammation in cerebral ischemia-reperfusion injury. This study intended to assess influences of BMSC-released exosomes on oxidative stress and inflammation following ischemic stroke.

METHODS

In vitro and in vivo models were developed using oxygen-glucose deprivation/reperfusion (OGD/R) and middle cerebral artery occlusion (MCAO), respectively. After exosome isolation, co-culture experiments of BMSCs or BMSC-derived exosomes and OGD/R-treated BV-2 cells were implemented to evaluate the impacts of BMSCs or BMSC-secreted exosomes on proliferation, inflammation, oxidative stress, and apoptosis. The gain-of-function experiments of ZFAS1 or microRNA (miR)-15a-5p were conducted to investigate the associated mechanisms. Besides, MCAO mice were injected with exosomes from BMSCs overexpressing ZFAS1 for in vivo verification. The binding of ZFAS1 to miR-15a-5p was assessed through dual-luciferase reporter gene assay.

RESULTS

Co-culture with BMSCs accelerated proliferation and downregulated IL-1β, IL-6, and TNF-α in OGD/R-exposed BV-2 cells, accompanied by increased SOD level and decreased MDA level and apoptosis, all of which were nullified by inhibiting exosome secretion. Mechanistically, ZFAS1 bound to miR-15a-5p to negatively orchestrate its expression. In addition, BMSC-released exosomes or BMSC-secreted exosomal ZFAS1 augmented proliferation but reduced oxidative stress, apoptosis, and inflammation in OGD/R-exposed BV-2 cells, whereas these impacts of BMSC-released exosomal ZFAS1 were nullified by overexpressing miR-15a-5p. Moreover, BMSC-derived exosomal ZFAS1 diminished MCAO-induced oxidative stress, cerebral infarction, and inflammation in mice.

CONCLUSIONS

Conclusively, BMSC-released exosomes might carry long noncoding RNA ZFAS1 to curb oxidative stress and inflammation related to ischemic stroke, which was possibly realized through miR-15a-5p inhibition.

Identification of pyroptosis-related immune signature and drugs for ischemic stroke

Background: Ischemic stroke (IS) is a common and serious neurological disease, and multiple pathways of cell apoptosis are implicated in its pathogenesis. Recently, extensive studies have indicated that pyroptosis is involved in various diseases, especially cerebrovascular diseases. However, the exact mechanism of interaction between pyroptosis and IS is scarcely understood. Thus, we aimed to investigate the impact of pyroptosis on IS-mediated systemic inflammation.

Methods: First, the RNA regulation patterns mediated by 33 pyroptosis-related genes identified in 20 IS samples and 20 matched-control samples were systematically evaluated. Second, a series of bioinformatics algorithms were used to investigate the contribution of PRGs to IS pathogenesis. We determined three composition classifiers of PRGs which potentially distinguished healthy samples from IS samples according to the risk score using single-variable logistic regression, LASSO-Cox regression, and multivariable logistic regression analyses. Third, 20 IS patients were classified by unsupervised consistent cluster analysis in relation to pyroptosis. The association between pyroptosis and systemic inflammation characteristics was explored, which was inclusive of immune reaction gene sets, infiltrating immunocytes and human leukocyte antigen genes.

Results: We identified that AIM2, SCAF11, and TNF can regulate immuno-inflammatory responses after strokes via the production of inflammatory factors and activation of the immune cells. Meanwhile, we identified distinct expression patterns mediated by pyroptosis and revealed their immune characteristics, differentially expressed genes, signaling pathways, and target drugs.

Conclusion: Our findings lay a foundation for further research on pyroptosis and IS systemic inflammation, to improve IS prognosis and its responses to immunotherapy.

Consensus clustering of gene expression profiles in peripheral blood of acute ischemic stroke patients

Acute ischemic stroke (AIS) is a primary cause of mortality and morbidity worldwide. Currently, no clinically approved immune intervention is available for AIS treatment, partly due to the lack of relevant patient classification based on the peripheral immunity status of patients with AIS. In this study, we adopted the consensus clustering approach to classify patients with AIS into molecular subgroups based on the transcriptomic profiles of peripheral blood, and we identified three distinct AIS molecular subgroups and 8 modules in each subgroup by the weighted gene co-expression network analysis. Remarkably, the pre-ranked gene set enrichment analysis revealed that the co-expression modules with subgroup I-specific signature genes significantly overlapped with the differentially expressed genes in AIS patients with hemorrhagic transformation (HT). With respect to subgroup II, exclusively male patients with decreased proteasome activity were identified. Intriguingly, the majority of subgroup III was composed of female patients who showed a comparatively lower level of AIS-induced immunosuppression (AIIS). In addition, we discovered a non-linear relationship between female age and subgroup-specific gene expression, suggesting a gender- and age-dependent alteration of peripheral immunity. Taken together, our novel AIS classification approach could facilitate immunomodulatory therapies, including the administration of gender-specific therapeutics, and attenuation of the risk of HT and AIIS after ischemic stroke.

Systemic inflammation after stroke: implications for post-stroke comorbidities

Immunological mechanisms have come into the focus of current translational stroke research, and the modulation of neuroinflammatory pathways has been identified as a promising therapeutic approach to protect the ischemic brain. However, stroke not only induces a local neuroinflammatory response but also has a profound impact on systemic immunity. In this review, we will summarize the consequences of ischemic stroke on systemic immunity at all stages of the disease, from onset to long‐term outcome, and discuss underlying mechanisms of systemic brain‐immune communication. Furthermore, since stroke commonly occurs in patients with multiple comorbidities, we will also overview the current understanding of the potential role of systemic immunity in common stroke‐related comorbidities, such as cardiac dysfunction, atherosclerosis, diabetes, and infections. Finally, we will highlight how targeting systemic immunity after stroke could improve long‐term outcomes and alleviate comorbidities of stroke patients.

4-Ethylguaiacol Modulates Neuroinflammation and Promotes Heme Oxygenase-1 Expression to Ameliorate Brain Injury in Ischemic Stroke

Ischemic stroke is caused by a sudden reduction in cerebral blood flow that subsequently induces a complex cascade of pathophysiological responses, leading to brain inflammation and irreversible infarction. 4-ethylguaiacol (4-EG) is reported to suppress inflammatory immune responses. However, whether 4-EG exerts anti-inflammatory effects in ischemic stroke remains unexplored. We evaluated the therapeutic potential of 4-EG and examined the cellular and molecular mechanisms underlying the protective effects of 4-EG in ischemic stroke. The effect of 4-EG in ischemic stroke was determined by using a transient middle cerebral artery occlusion (MCAO) animal model followed by exploring the infarct size, neurological deficits, microglia activation, inflammatory cytokine production, blood–brain barrier (BBB) disruption, brain endothelial cell adhesion molecule expression, and microglial heme oxygenase-1 (HO-1) expression. Nrf2^-/- and HO-1 inhibitor ZnPP-treated mice were also subjected to MCAO to evaluate the role of the Nrf2/HO-1 pathway in 4-EG-mediated protection in ischemic stroke. We found that 4-EG attenuated infarct size and neurological deficits, and lessened BBB disruption in ischemic stroke. Further investigation revealed that 4-EG suppressed microglial activation, peripheral inflammatory immune cell infiltration, and brain endothelial cell adhesion molecule upregulation in the ischemic brain. Finally, we identified that the protective effect of 4-EG in ischemic stroke was abolished in Nrf2^-/– and ZnPP-treated MCAO mice. Our results identified that 4-EG confers protection against ischemic stroke and reveal that the protective effect of 4-EG in ischemic stroke is mediated through the induction of the Nrf2/HO1 pathway. Thus, our findings suggest that 4-EG could be developed as a novel therapeutic agent for the treatment of ischemic stroke.

Preoperative Serum Alkaline Phosphatase and Neurological Outcome of Cerebrovascular Surgery

This study evaluated the relationship between the preoperative alkaline phosphatase (ALP) level and major postoperative neurological complications in patients undergoing cerebral bypass surgery. This was a retrospective analysis of a prospective database of all patients undergoing cerebral bypass surgery after a diagnosis of cerebrovascular stenosis or occlusion between May 2003 and August 2017. The patients were divided into tertiles based on serum alkaline phosphatase (ALP) levels (low: <63, intermediate: 63~79, and high: ALP > 79 IU/mL). The incidence of neurological events according to ALP level was analyzed. The study analyzed 211 cases. The incidence of acute infarction was highest in the third serum ALP tertile (5.7% vs. 2.9% vs. 16.9% in the first, second, and third tertile, respectively, p = 0.007). Logistic regression analysis showed that the third tertile of serum ALP was an independent predictor of acute cerebral infarction (odds ratio 3.346, 95% confidence interval 1.026−10.984, p = 0.045). On Kaplan−Meier time-to-event curves, the incidence of acute infarction increased significantly with ALP (log rank = 0.048). Preoperative serum ALP level can be used as a biomarker to predict acute cerebral infarction in patients undergoing cerebral bypass surgery for vascular stenosis or occlusion.

Integrated Network Pharmacology and UPLC/Q-TOF-MS Screen System to Exploring Anti-Inflammatory Active Components and Mechanism of Shunaoxin Pills

Background

Chronic cerebral ischemia (CCI) is a pathological condition associated with a variety of cerebrovascular diseases. Shunaoxin pills (SNX) are a traditional Chinese medicine (TCM) used to improve blood circulation. However, its multicomponent and multitarget features make it difficult to decipher the molecular mechanisms.

Objective

Thus, in this study, we aimed to identify the key anti-inflammatory components of SNX as markers for standardization and quality control and the potential pharmacological mechanisms of SNX in the treatment of CCI by network pharmacology to provide scientific evidence of its clinical efficacy.

Methods

We evaluated the anti-inflammatory effect of SNX using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectroscopy (UPLC/Q-TOF-MS) combined with a dual-luciferase reporter assay for nuclear factor kappa B (NF-κB) inhibition to identify the active components in SNX. In addition, key pathways involved in the anti-inflammatory effect of SNX were predicted using a network pharmacology approach, and some crucial proteins and pathways were further validated by Western blotting.

Results

Shunaoxin pills inhibited NF-κB through tumor necrosis factor-α (TNF-α) stimulation in 293T cells. The therapeutic effect may be related to 10 pathways regulated by ligustilide, ferulic acid, ligustrazine, and senkyunolide I. It was further confirmed that ligustilide could reduce the inflammatory response by inhibiting the phosphorylation of p38 and 3-phosphoinositide-dependent kinase 1 (PDK1).

Conclusions

Ligustilide, senkyunolide I, ferulic acid, and ligustrazine could be used as anti-inflammatory Q-markers to control the quality of SNX, and p38 and PDK1 might be potential targets of SNX in the treatment of CCI.

The Influence of Gut Dysbiosis in the Pathogenesis and Management of Ischemic Stroke

Recent research on the gut microbiome has revealed the influence of gut microbiota (GM) on ischemic stroke pathogenesis and treatment outcomes. Alterations in the diversity, abundance, and functions of the gut microbiome, termed gut dysbiosis, results in dysregulated gut–brain signaling, which induces intestinal barrier changes, endotoxemia, systemic inflammation, and infection, affecting post-stroke outcomes. Gut–brain interactions are bidirectional, and the signals from the gut to the brain are mediated by microbially derived metabolites, such as trimethylamine N-oxide (TMAO) and short-chain fatty acids (SCFAs); bacterial components, such as lipopolysaccharide (LPS); immune cells, such as T helper cells; and bacterial translocation via hormonal, immune, and neural pathways. Ischemic stroke affects gut microbial composition via neural and hypothalamic–pituitary–adrenal (HPA) pathways, which can contribute to post-stroke outcomes. Experimental and clinical studies have demonstrated that the restoration of the gut microbiome usually improves stroke treatment outcomes by regulating metabolic, immune, and inflammatory responses via the gut–brain axis (GBA). Therefore, restoring healthy microbial ecology in the gut may be a key therapeutic target for the effective management and treatment of ischemic stroke.

Potentials of Neuropeptides as Therapeutic Agents for Neurological Diseases

Despite recent leaps in modern medicine, progress in the treatment of neurological diseases remains slow. The near impermeable blood-brain barrier (BBB) that prevents the entry of therapeutics into the brain, and the complexity of neurological processes, limits the specificity of potential therapeutics. Moreover, a lack of etiological understanding and the irreversible nature of neurological conditions have resulted in low tolerability and high failure rates towards existing small molecule-based treatments. Neuropeptides, which are small proteinaceous molecules produced by the body, either in the nervous system or the peripheral organs, modulate neurological function. Although peptide-based therapeutics originated from the treatment of metabolic diseases in the 1920s, the adoption and development of peptide drugs for neurological conditions are relatively recent. In this review, we examine the natural roles of neuropeptides in the modulation of neurological function and the development of neurological disorders. Furthermore, we highlight the potential of these proteinaceous molecules in filling gaps in current therapeutics.

Association of Neutrophil-to-Lymphocyte Ratio with the Risk of Fatal Stroke Occurrence in Older Chinese

BACKGROUND

Associations of neutrophil-to-lymphocyte ratio (NLR) and its longitudinal change with risk of fatal strokes are unclear in older populations.

METHODS

In this retrospective analysis, a total of 27,799 participants were included and followed up for a mean of 14.3 years (standard deviation = 3.2). 838 stroke deaths were recorded. Cox proportional hazards regression was used to assess associations of NLR with fatal strokes.

RESULTS

Compared to those in the first quartile and after adjustment for a series of factors, the participants in the highest neutrophil quartile had an increased risk of fatal all stroke (adjusted hazard ratio (aHR) = 1.45, 95% confidence interval (CI), 1.18-1.79) and fatal ischaemic stroke (aHR = 1.58, 95% CI, 1.17-2.12). Restricted cubic splines showed an increased trend of relationship between the NLR and fatal all stroke. The participants with the highest NLR quartile had an increased risk of fatal all stroke (aHR = 1.52, 95% CI, 1.23-1.88) and fatal ischaemic stroke (aHR = 1.59, 95% CI, 1.13-2.26), respectively; Similar associations repeated after further C-reactive protein adjustment; a 21% and a 32% increased risk of fatal all stroke and fatal ischaemic stroke showed in a continuous variable model. Those in NLR change with 5% increase had a 70% increased risk of fatal all stroke (aHR = 1.70, 95%CI, 1.13-2.57), compared to those in stable (-5%∼5%).

CONCLUSIONS

Higher NLR was associated with an increased risk of fatal all stroke and fatal ischaemic stroke, and its longitudinal change increase of ≥ 5% was associated with an increased risk of fatal all stroke in a relatively healthy older population.

Knocking Down Peroxiredoxin 6 Aggravates Cerebral Ischemia-Reperfusion Injury by Enhancing Mitophagy

Cerebral ischemia-reperfusion injury (IRI) is caused by reperfusion following ischemia. Mitophagy is closely related to cerebral IRI. Mitophagy disorder or excess may be harmful and lead to neuronal apoptosis. Peroxiredoxin 6 (PRDX6) is an antioxidant protein and plays an important role in ischemic stroke. However, the relationship between PRDX6 and mitophagy is not clear at present. In order to explore and solve this problem. We have established a middle cerebral artery occlusion (MCAO) model of cerebral ischemia-reperfusion in SD rats and knockdown PRDX6 and PINK1 with lentivirus. Knocking down PRDX6 led to further aggravation of cerebral IRI. Our research found that knockdown PRDX6 increased the expression of mitophagy-related and apoptosis-related proteins. Knocking down PINK1 relieved mitophagy and apoptosis caused by knocking down PRDX6. In conclusion, knockdown of PRDX6 could aggravate cerebral IRI by enhancing PINK1/PARKIN pathway mediated mitophagy, and this effect could increase neuronal apoptosis.

Exogenous inter-α inhibitor proteins prevent cell death and improve ischemic stroke outcomes in mice

Inter-α inhibitor proteins (IAIPs) are a family of endogenous plasma and extracellular matrix molecules. IAIPs suppress proinflammatory cytokines, limit excess complement activation, and bind extracellular histones to form IAIP-histone complexes, leading to neutralization of histone-associated cytotoxicity in models of sepsis. Many of these detrimental processes also play critical roles in the pathophysiology of ischemic stroke. In this study, we first assessed the clinical relevance of IAIPs in stroke and then tested the therapeutic efficacy of exogenous IAIPs in several experimental stroke models. IAIP levels were reduced in both ischemic stroke patients and in mice subjected to experimental ischemic stroke when compared with controls. Post-stroke administration of IAIP significantly improved stroke outcomes across multiple stroke models, even when given 6 hours after stroke onset. Importantly, the beneficial effects of delayed IAIP treatment were observed in both young and aged mice. Using targeted gene expression analysis, we identified a receptor for complement activation, C5aR1, that was highly suppressed in both the blood and brain of IAIP-treated animals. Subsequent experiments using C5aR1-knockout mice demonstrated that the beneficial effects of IAIPs are mediated in part by C5aR1. These results indicate that IAIP is a potential therapeutic candidate for the treatment of ischemic stroke.

The Prognostic Determinant of Interleukin-10 in Patients with Acute Ischemic Stroke: An Analysis from the Perspective of Disease Management

Background

In patients with ischemic stroke, the role of anti-inflammatory cytokine Interleukin-10 (IL-10) in predicting risk and outcomes is not very clear. This study is aimed at prospectively assessing the prognostic determinant value of IL-10 in patients with acute ischemic stroke in a cohort of Chinese people.

Methods

In a prospective cohort study, consecutive first-ever patients with acute ischemic stroke admitted to our hospital were included from October 2019 to October 2020. The serum level of IL-10 was measured at baseline. A structured follow-up telephone interview was performed on day 90 after admission. Logistic regression analyses were used to assess the prognostic value of IL-10 to predict the poor functional outcome (defined as a modified Rankin Scale score of 3 to 6) and mortality.

Results

The median age of the 236 enrolled patients was 65 years (interquartile range (IQR), 56-76), and 57.6% were male. There was a negative correlation between the National Institutes of Health Stroke Scale (NIHSS) score and IL-10 serum levels (r (Spearman) = −0.221, P = 0.001). Patients with elevated IL-10 levels (> the highest quartile = 5.24 pg/mL; n = 79) were at significantly lower risk of poor functional outcomes (odds ratio (OR), 0.35; 95% confidence interval (CI), 0.19 to 0.63; P < 0.001) and mortality (OR = 0.24; 95% CI = 0.11–0.52; P < 0.001) compared with patients with IL-10 levels in the lowest three quartiles.

Conclusions

Reduced serum levels of IL-10 were independently associated with both the clinical severity at admission and a poor functional prognosis in ischemic stroke patients, suggesting that the anti-inflammatory cytokine IL-10 was an important prognostic determinant.

High Neutrophil-Lymphocyte Ratio Predicts Post-stroke Cognitive Impairment in Acute Ischemic Stroke Patients

Background and Aims: Systemic inflammation is associated with an increased risk of cognitive impairment and dementia, but the associations between them in stroke patients are less clear. We examined the impact of systemic inflammation represented as the neutrophil-lymphocyte ratio (NLR) on the development of post-stroke cognitive impairment (PSCI) and domain-specific cognitive outcomes 3-month after ischemic stroke. Methods: Using prospective stroke registry data, we consecutively enrolled 345 participants with ischemic stroke whose cognitive functions were evaluated 3-month after stroke. Their cognition was assessed with the Korean version of the Vascular Cognitive Impairment Harmonization Standards and the Korean-Mini Mental Status Examination. PSCI was defined as a z-score of < -2 standard deviations for age, sex, and education adjusted means in at least one cognitive domain. The participants were categorized into five groups according to the quintiles of NLR (lowest NLR, Q1). The cross-sectional association between NLR and PSCI was assessed using multiple logistic regression, adjusting for age, sex, education, vascular risk factors, and stroke type. Results: A total of 345 patients were enrolled. The mean age was 63.0 years and the median NIHSS score and NLR were 2 [1-4] and 2.26 [1.65-2.91], respectively. PSCI was identified in 71 (20.6%) patients. NLR was a significant predictor for PSCI both as a continuous variable (adjusted OR, 1.14; 95% CI, 1.00-1.31) and as a categorical variable (Q5, adjusted OR, 3.26; 95% CI, 1.17-9.08). Patients in the Q5 group (NLR ≥ 3.80) showed significantly worse performance in global cognition and in visuospatial and memory domains. Conclusions: NLR in the acute stage of ischemic stroke was independently associated with PSCI at 3 months after stroke, and high NLR was specifically associated with cognitive dysfunction in the memory and visuospatial domains. Thus, systemic inflammation may be a modifiable risk factor that may influence cognitive outcomes after stroke.

Construction of lncRNA-Mediated ceRNA Network for Investigating Immune Pathogenesis of Ischemic Stroke

Ischemic stroke (IS) is a common and serious neurological disease. Extensive evidence indicates that activation of the immune system contributes significantly to the development of IS pathology. In recent years, some long non-coding RNAs (lncRNAs), acting as competing endogenous RNAs (ceRNAs), have been reported to affect IS process, especially the immunological response after stroke. However, the roles of lncRNA-mediated ceRNAs in immune pathogenesis of IS are not systemically investigated. In the present study, we generated a global immune-related ceRNA network containing immune-related genes (IRGs), miRNAs, and lncRNAs based on experimentally verified interactions. Further, we excavated an IS immune-related ceRNA (ISIRC) network through mapping significantly differentially expressed IRGs, miRNAs, and lncRNAs of patients with IS into the global network. We analyzed the topological properties of the two networks, respectively, and found that lncRNA NEAT1 and lncRNA KCNQ1OT1 played core roles in aforementioned two immune-related networks. Moreover, the results of functional enrichment analyses revealed that lncRNAs in the ISIRC network were mainly involved in several immune-related biological processes and pathways. Finally, we identified 17 lncRNAs which were highly related to the immune mechanism of IS through performing random walk with restart for the ISIRC network. Importantly, it has been confirmed that NEAT1, KCNQ1OT1, GAS5, and RMRP could regulate immuno-inflammatory response after stroke, such as production of inflammatory factors and activation of the immune cells. Our results suggested that lncRNAs exerted an important role in the immune pathogenesis of IS and provided a new strategy to do research on IS.

Therapeutic Potential of Cytokines in Demyelinating Lesions After Stroke

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

Significantly Reduced Alanine Aminotransferase Level Increases All-Cause Mortality Rate in the Elderly after Ischemic Stroke

(1) Background: A significantly reduced alanine aminotransferase (ALT) level is being recognized as a risk factor of increasing mortality in the elderly in relation to frailty. In the elderly, both frailty and ischemic stroke are not only common, but are also associated with mortality. The aim of this research was to investigate whether a significantly reduced ALT level increases the all-cause mortality rate in the elderly with ischemic stroke. (2) Methods: Between February 2014 and April 2019, a retrospective study of 901 patients with ischemic stroke admitted to a university-affiliated hospital was conducted. Cox proportional hazard regression was used to determine whether a significantly reduced ALT level is an independent risk factor for mortality in elderly patients after an ischemic stroke. (3) Results: This study enrolled 323 older adults (age ≥ 65 years) who were first diagnosed with ischemic stroke. The mean age of the participants was 76.5 ± 6.6 years, the mean survival time was 37.1 ± 20.4 months, and the number of deaths was 96 (29.7%). Our results showed that reduced ALT level (less than 10 U/L) increased the risk of all-cause mortality in the elderly after ischemic stroke (adjusted HR: 3.24, 95% CI: 1.95–5.41; p < 0.001). (4) Conclusions: A significantly reduced ALT level at the time of diagnosis (less than 10 U/L) is an independent risk factor that increases the mortality rate in the elderly after ischemic stroke.

Toll-like receptor 4-mediated cytokine synthesis and post-stroke depressive symptoms

Altered cytokine synthesis thought to contribute to the pathophysiology of post-stroke depression (PSD). Toll-like receptor 4 (TLR4) is a master regulator of innate immunity. The aim of this study was to explore the putative association between TLR4-mediated cytokine synthesis and subsequent symptoms of PSD. In total, 262 patients with ischemic stroke and without a history of PSD were included. Depressive symptoms were assessed using the Patient Health Questionnaire-9 in 170 patients on Day 8 and in 146 at 3 months after stroke. Blood samples taken on Day 3 after stroke were stimulated ex vivo with lipopolysaccharide (LPS). Ex vivo synthesized cytokines (TNFα, IP-10, IL-1β, IL-6, IL-8, IL-10, and IL-12p70) and circulating cytokines (TNFα, IL-6, sIL-6R, and IL-1ra) were measured using the enzyme-linked immunoassay or cytometric method. RNA sequencing was used to determine the gene expression profile of LPS-induced cytokines and chemokines. LPS-induced cytokine synthesis and the gene expression of TLR4-dependent cytokines and chemokines did not differ between patients with and without greater depressive symptoms. The plasma level of IL-6, but not TNFα, sIL-6R, and IL-1ra, was higher in patients who developed depressive symptoms at 3 months after stroke (median: 4.7 vs 3.4 pg/mL, P = 0.06). Plasma IL-6 predicted the severity of depressive symptoms at 3 months after stroke (β = 0.42, P = 0.03). In conclusion, TLR4-dependent cytokine synthesis was not associated with greater post-stroke depressive symptoms in this study. Circulating IL-6 might be associated with depressive symptoms occurring at 3 months after stroke.

Elevated plasma levels of galectin-3 binding protein are associated with post-stroke delirium - A pilot study

To explore the role of systemic inflammation in post-stroke delirium, we investigated the level of two inflammatory mediators: high mobility group box 1 (HMGB1) and galectin-3 binding protein (Gal-3BP). Of 571 stroke patients, we compared plasma levels of HMGB1 and Gal-3BP in 79 delirious patients with 81 non-delirious patients matched for age and stroke severity. Delirious patients had higher Gal-3BP level (median: 1440 vs 1053 ng/mL, P < 0.01). An elevated level of Gal-3BP was associated with an increased risk of delirium. HMGB1 levels did not differ between groups. Our results suggest that pro-inflammatory monocytes and macrophages might be involved in delirium pathophysiology.

Serum Interleukin-37 Increases in Patients after Ischemic Stroke and Is Associated with Stroke Recurrence

Background

This study seeks to assess interleukin-37 (IL-37) serum level in acute ischemic stroke and the value of predicting 3-month stroke recurrence and functional outcome in acute ischemic stroke.

Methods

From January 1, 2018, to June 30, 2019, all consecutive first-ever acute ischemic stroke patients from our hospital, China, were included. Serum samples, clinical information, and stroke severity (defined by the National Institute of Health stroke scale (NIHSS) score) were collected at baseline. Serum IL-37 level was measured by the enzyme-linked immunosorbent assay (ELISA) method. Functional impairment (defined by the modified Rankin scale (mRS)) and recurrent stroke were assessed 3 months after admission. The relation of IL-37 with either clinical severity at baseline, unfavorable functional outcome, or stroke recurrence at follow-up was evaluated by logistic regression analysis, and the results were presented as odds ratios (OR) with 95% confidence intervals (CI).

Results

Three hundred and ten stroke patients were included. The median IL-37 serum level in those patients was 344.1 pg/ml (interquartile range (IQR), 284.4-405.3 vs. control cases: 122.3 pg/ml (IQR, 104.4-1444.0); P < 0.001). At 3 months, a total of 36 (11.6%) patients had a stroke recurrence. IL-37 serum levels in those patients were higher than in those patients without stroke recurrence (417.0 pg/ml (IQR, 359.3-436.1) vs. 333.3 pg/ml (279.0-391.0)). In a logistic model adjusted for other factors, IL-37 in the highest quartile (>405.3 pg/ml) was still associated with recurrent stroke (OR = 3.32; 95%CI = 2.03–6.13; P < 0.001). IL-37 could promote the NIHSS score (area under the curve (AUC) of the IL-37/NIHSS, 0.75; 95% CI, 0.67–0.83; P < 0.001), corresponding to a difference of 0.085 (0.005). Serum IL-37 increases in patients with poor outcome, and an IL-37 in the highest quartile is related to poor outcome (OR = 4.85; 95%CI = 3.11 − 8.22; P < 0.001).

Conclusion

Serum IL-37 increased in patients after ischemic stroke and was associated with stroke recurrence events and poor stroke outcomes. Large randomized controlled trials should be carried out to confirm whether IL-37 lowering treatment improves stroke prognosis.

Predictors of mortality and disability in stroke-associated pneumonia

Whilst stroke-associated pneumonia (SAP) is common and associated with poor outcomes, less is known about the determinants of these adverse clinical outcomes in SAP. To identify the factors that influence mortality and morbidity in SAP. Data for patients with SAP (n = 854) were extracted from a regional Hospital Stroke Register in Norfolk, UK (2003–2015). SAP was defined as pneumonia occurring within 7 days of admission by the treating clinicians. Mutlivariable regression models were constructed to assess factors influencing survival and the level of disability at discharge using modified Rankin Scale [mRS]. Mean (SD) age was 83.0 (8.7) years and ischaemic stroke occurred in 727 (85.0%). Mortality was 19.0% at 30 days and 44.0% at 6 months. Stroke severity assessment using National Institutes of Health Stroke Scale was not recorded in the data set although Oxfordshire Community Stroke Project was Classification. In the multivariable analyses, 30-day mortality was independently associated with age (OR 1.04, 95% CI 1.01–1.07, p = 0.01), haemorrhagic stroke (2.27, 1.07–4.78, p = 0.03) and pre-stroke disability (mRS 4–5 v 0–1: 6.45, 3.12–13.35, p < 0.001). 6-month mortality was independently associated with age (< 0.001), pre-stroke disability (p < 0.001) and certain comorbidities, including the following: dementia (6.53, 4.73–9.03, p < 0.001), lung cancer (2.07, 1.14–3.77, p = 0.017) and previous transient ischemic attack (1.94, 1.12–3.36, p = 0.019). Disability defined by mRS at discharge was independently associated with age (1.10, 1.05–1.16, p < 0.001) and plasma C-reactive protein (1.02, 1.01–1.03, p = 0.012). We have identified non-modifiable determinants of poor prognosis in patients with SAP. Further studies are required to identify modifiable factors which may guide areas for intervention to improve the prognosis in SAP in these patients.

Bacterial lipopolysaccharide is associated with stroke

We aimed to determine if plasma levels of bacterial lipopolysaccharide (LPS) and lipoteichoic acid (LTA) are associated with different causes of stroke and correlate with C-reactive protein (CRP), LPS-binding protein (LBP), and the NIH stroke scale (NIHSS). Ischemic stroke (cardioembolic (CE), large artery atherosclerosis (LAA), small vessel occlusion (SVO)), intracerebral hemorrhage (ICH), transient ischemic attack (TIA) and control subjects were compared (n = 205). Plasma LPS, LTA, CRP, and LBP levels were quantified by ELISA. LPS and CRP levels were elevated in ischemic strokes (CE, LAA, SVO) and ICH compared to controls. LBP levels were elevated in ischemic strokes (CE, LAA) and ICH. LTA levels were increased in SVO stroke compared to TIA but not controls. LPS levels correlated with CRP and LBP levels in stroke and TIA. LPS, LBP and CRP levels positively correlated with the NIHSS and WBC count but negatively correlated with total cholesterol. Plasma LPS and LBP associate with major causes of ischemic stroke and with ICH, whereas LPS/LBP do not associate with TIAs. LTA only associated with SVO stroke. LPS positively correlated with CRP, LBP, and WBC but negatively correlated with cholesterol. Higher LPS levels were associated with worse stroke outcomes.

Serum ICAM-1 as a Predictor of Prognosis in Patients with Acute Ischemic Stroke

Objective

Inflammation is one of the key mechanisms involved in functional impairment after stroke. Intercellular adhesion molecule-1 (ICAM-1) is an important inflammatory molecule in the body. The purpose of our study was to determine the correlation between ICAM-1 and the prognosis of acute ischemic stroke (AIS).

Methods

286 AIS patients treated at Beijing Tiantan Hospital were continuously included in the study. The demographic data of the patients were collected, and the fasting blood within 24 hours of admission was collected to detect the clinical indicators. The functional prognosis was measured using the modified Rankin Scale (mRS) 3 months after stroke. The poor prognosis is defined as mRS ≥ 3. The enzyme-linked immunosorbent assay (ELISA) was used to determine the serum ICAM-1 levels.

Results

The serum ICAM-1 levels of patients with poor prognosis were significantly higher than that of patients with good prognosis (144.2 ± 14.8 vs 117.5 ± 12.1 pg/ml). Receiver operating characteristic curve (ROC) analysis showed that the sensitivity and specificity of serum ICAM-1 for predicting the prognosis of AIS were 74% and 76%, respectively. In logistic regression analysis, the serum ICAM-1 level is still an independent predictor of poor prognosis (odds ratio [OR]: 0.52; 95% confidence interval [CI]: 0.318-0.839).

Conclusions

Higher serum ICAM-1 levels on admission in AIS patients might increase the risk of poor prognosis.

Extremely Low Serum Alanine Transaminase Level Is Associated with All-Cause Mortality in the Elderly after Intracranial Hemorrhage

OBJECTIVE

Extremely low alanine transaminase (ALT) levels are associated with all-cause mortality in frail elderly individuals; the clinical significance of ALT as a reliable biomarker is now being considered. Predicting mortality with routine tests at the time of diagnosis is important for managing patients after intracranial hemorrhage. We aimed to investigate whether an extremely low ALT level is associated with mortality in the elderly after intracranial hemorrhage.

METHODS

A retrospective review was performed on 455 patients with intracranial hemorrhage admitted to a university-affiliated tertiary care hospital from February 2014 to May 2019. Multivariate Cox regression analysis was performed for all ages and for each age group to determine whether an extremely low ALT level is an independent predictor of mortality only in the elderly.

RESULTS

Overall, 294 patients were enrolled, and the mean age of the subjects was 59.1 years, with 99 (33.8%) aged ≥65 years. The variables associated with all-cause mortality in all subjects were age, C-reactive protein (CRP) levels, hemoglobin (Hb) levels (<11 g/dL), and initial Glasgow coma scale (GCS) scores. In young patients, CRP, low Hb levels, and initial GCS scores were significantly associated with all-cause mortality. However, in the elderly (≥65 years), the variables significantly associated with allcause mortality were extremely low levels of ALT (<10 U/L) (adjusted hazard ratio, 3.313; 95% confidence interval, 1.232-8.909; p=0.018) and initial GCS scores.

CONCLUSION

Extremely low ALT level (<10 U/L) at the time of diagnosis is a significant risk factor for all-cause mortality in the elderly after intracranial hemorrhage.

Inhibition of Caspase-1 Ameliorates Ischemia-Associated Blood-Brain Barrier Dysfunction and Integrity by Suppressing Pyroptosis Activation

Ischemic cerebral infarction represents a significant cause of disability and death worldwide. Caspase-1 is activated by the NLRP3/ASC pathway and inflammasomes, thus triggering pyroptosis, a programmed cell death. In particular, this death is mediated by gasdermin D (GSDMD), which induces secretion of interleukin (IL)-1β and IL-18. Accordingly, inhibition of caspase-1 prevents the development and worsening of multiple neurodegenerative diseases. However, it is not clear whether inhibition of caspase-1 can preserve blood-brain barrier (BBB) integrity following cerebral infarction. This study therefore aimed at understanding the effect of caspase-1 on BBB dysfunction and its underlying mechanisms in permanent middle cerebral artery occlusion (MCAO). Our findings in rat models revealed that expression of caspase-1 was upregulated following MCAO-induced injury in rats. Consequently, pharmacologic inhibition of caspase-1 using vx-765 ameliorated ischemia-induced infarction, neurological deficits, and neuronal injury. Furthermore, inhibition of caspase-1 enhanced the encapsulation rate of pericytes at the ischemic edge, decreased leakage of both Evans Blue (EB) and matrix metalloproteinase (MMP) proteins, and upregulated the levels of tight junctions (TJs) and tissue inhibitors of metalloproteinases (TIMPs) in MCAO-injured rats. This in turn improved the permeability of the BBB. Meanwhile, vx-765 blocked the activation of ischemia-induced pyroptosis and reduced the expression level of inflammatory factors such as caspase-1, NLRP3, ASC, GSDMD, IL-1β, and IL-18. Similarly, vx-765 treatment significantly reduced the expression levels of inflammation-related receptor for advanced glycation end products (RAGE), high-mobility family box 1 (HMGB1), mitogen-activated protein kinase (MAPK), and nuclear factor-κB (NF-κB). Evidently, inhibition of caspase-1 significantly improves ischemia-associated BBB permeability and integrity by suppressing pyroptosis activation and the RAGE/MAPK pathway.

Clinical Features and Hearing Outcomes of Sudden Sensorineural Hearing Loss in Diabetic Patients

Background and Objectives

This study aimed to evaluate the clinical features and the clinical factors associated with prognosis of sudden sensorineural hearing loss (SSNHL) in diabetic patients.

Subjects and Methods

Forty-nine diabetic with unilateral SSNHL were retrospectively included. All patients received systemic high dose steroid therapy within one month after onset and had more than one month of follow-up audiogram. The basic characteristics of the patients, initial and follow-up audiograms, laboratory data, and methods of steroid treatment were collected.

Results

Compared to reference values in healthy subjects, 79%, 55%, and 45% of the patients had higher values of mean neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and lymphocyte-monocyte ratio (LMR), respectively. Older patients had significantly less degree of hearing loss, but they also had significantly worse hearing thresholds in the unaffected ear. After steroid treatment, less than half patients (47%) showed hearing recovery. Simultaneous intratympanic dexamethasone (ITD) injections with systemic steroid did not confer an additional hearing gain or an earlier recovery rate in diabetic patients with SSNHL. In the multivariate analysis, initial hearing thresholds of affected ear and timing of steroid treatment were significantly associated with hearing prognosis in diabetic patients with SSNHL.

Conclusions

Diabetic patients with SSNHL tended to have increased NLR, LMR, and PLR, which are reported to be associated with microvascular angiopathy. Simultaneous ITD injections to improve hearing recovery in diabetic patients with SSNHL seems unnecessary.

Perspective of SGLT2 Inhibition in Treatment of Conditions Connected to Neuronal Loss: Focus on Alzheimer's Disease and Ischemia-Related Brain Injury

Sodium-glucose co-transporter 2 inhibitors (SGLT2i) are oral anti-hyperglycemic agents approved for the treatment of type 2 diabetes mellitus. Some reports suggest their presence in the central nervous system and possible neuroprotective properties. SGLT2 inhibition by empagliflozin has shown to reduce amyloid burden in cortical regions of APP/PS1xd/db mice. The same effect was noticed regarding tau pathology and brain atrophy volume. Empagliflozin presented beneficial effect on cognitive function, which may be connected to an increase in cerebral brain-derived neurotrophic factor. Canagliflozin and dapagliflozin may possess acetylcholinesterase inhibiting activity, resembling in this matter Alzheimer’s disease-registered therapies. SGLT2 inhibitors may prove to impact risk factors of atherosclerosis and pathways participating both in acute and late stage of stroke. Their mechanism of action can be related to induction in hepatocyte nuclear factor-1α, vascular endothelial growth factor-A, and proinflammatory factors limitation. Empagliflozin may have a positive effect on preservation of neurovascular unit in diabetic mice, preventing its aberrant remodeling. Canagliflozin seems to present some cytostatic properties by limiting both human and mice endothelial cells proliferation. The paper presents potential mechanisms of SGLT-2 inhibitors in conditions connected with neuronal damage, with special emphasis on Alzheimer’s disease and cerebral ischemia.

Blood biomarkers associated with inflammation predict poor prognosis in cerebral venous thrombosis:: a multicenter prospective observational study

BACKGROUND AND PURPOSE

Experimental studies suggest inflammation can contribute to blood barrier disruption and brain injury in cerebral venous thrombosis (CVT). We aimed to determine whether blood biomarkers of inflammation were associated with the evolution of brain lesions, persistent venous occlusion or functional outcome in patients with CVT.

METHODS

Pathophysiology of Venous Infarction-Prediction of Infarction and Recanalization in CVT (PRIORITy-CVT) was a multicenter prospective cohort study of patients with newly diagnosed CVT. Evaluation of neutrophil-to-lymphocyte ratio (NLR) and C-reactive protein (CRP) concentrations in peripheral blood samples was performed at admission in 62 patients. Additional quantification of interleukin (IL)-6 was performed at day 1, 3 and 8 in 35 patients and 22 healthy controls. Standardized magnetic resonance imaging was performed at day 1, 8 and 90. Primary outcomes were early evolution of brain lesion, early recanalization and functional outcome at 90 days.

RESULTS

Interleukin-6 levels were increased in patients with CVT with a peak at baseline. IL-6, NLR and CRP levels were not related with brain lesion outcomes or early recanalization but had a significant association with unfavourable functional outcome at 90 days (IL-6: OR = 1.28, 95% CI: 1.05-1.56, P = 0.046; NLR: OR = 1.39, 95% CI: 1.4-1.87, P = 0.014; CRP: OR = 1.756, 95% CI: 1.010-3.051, P = 0.029). Baseline IL-6 had the best discriminative capacity, with an area under the receiver operating characteristic curve to predict unfavourable functional outcome of 0.74 (P = 0.031).

CONCLUSIONS

Increased baseline levels of NLR, CRP and IL-6 may serve as new predictive markers of worse functional prognosis at 90 days in patients with CVT. No association was found between inflammatory markers and early evolution of brain lesion or venous recanalization.

Astragalin alleviates ischemia/reperfusion‑induced brain injury via suppression of endoplasmic reticulum stress

Excessive apoptosis and neuronal dysfunction are pathological features of ischemic stroke. Previous studies have demonstrated that astragalin (AST) exerted both anti‑​apoptotic and anti‑inflammatory effects in several types of disease, although its potential effect in ischemic stroke remains unclear. The purpose of the present study was to investigate the effects of AST on cerebral ischemia/reperfusion (I/R)‑induced brain injury and the underlying mechanisms. Brain injury was assessed in an experimental rat model using measurement of neurological scores and inflammatory factors. To assess the role of AST in I/R‑induced brain injury and the potential mechanism of action, SH5Y were treated with thapsigargin and AST. Apoptotic rate and ER stress levels were measured by western blotting, reverse transcription‑quantitative PCR and immunofluorescence staining. It was discovered that AST significantly improved long‑term neurological outcomes in rats following cerebral I/R injury, through the attenuation of the expression levels of apoptotic proteins (Bax and cleaved‑caspase‑3) and the release of inflammatory cytokines, as well as upregulating the expression levels of the anti‑apoptotic protein Bcl‑2. Furthermore, AST attenuated the expression levels of the endoplasmic reticulum (ER) stress‑related protein, glucose‑regulated protein, 78 kDa, as well as its downstream apoptotic mediators (CHOP and caspase‑12). Thapsigargin‑induced ER stress activation and apoptosis were also attenuated by AST in an in vitro neuronal cell culture model. In conclusion, these results suggested that AST may protect against I/R‑induced brain injury, thus, highlighting its therapeutic potential in patients with ischemic stroke.