Current Neurovascular Research - Online First

Introduction

Anandamide (AEA), an endocannabinoid, has demonstrated analgesic and anti-inflammatory properties in various experimental models. However, the mechanisms underlying its role in neuropathic pain and inflammation remain unclear.

Methods

Carrageenan-induced inflammation and Chronic Constriction Injury (CCI) were used to model inflammatory and neuropathic pain in Wistar rats. Behavioral tests (e.g., paw edema, mechanical and thermal hyperalgesia), hematological and biochemical analyses, and molecular studies (mRNA expression of AEA pathway enzymes) were conducted to evaluate AEA’s therapeutic potential.

Results

Anandamide significantly reduced paw edema and alleviated pain behaviors in CCI rats in a dose-dependent manner. It normalized hematological and biochemical markers and decreased levels of oxidative stress indicators (MDA, nitrite). mRNA analysis revealed upregulation of AEA degradation enzymes following CCI, indicating disrupted endocannabinoid signaling.

Discussion

AEA’s analgesic and anti-inflammatory actions appear to be mediated through CB1 receptor activation and modulation of ATP-sensitive potassium channels. The observed improvements in biochemical and behavioral markers suggest its efficacy in modulating neuroinflammation and neuropathic pain.

Conclusion

Anandamide demonstrates significant potential as a therapeutic agent in managing neuropathic and inflammatory pain. Further studies are warranted to elucidate its mechanisms and optimize its clinical applicability.

Introduction

This study investigated the neuroprotective mechanisms of ischemic postconditioning (IPostC) in ischemic stroke, focusing on ferroptosis and the regulatory role of the ferroptosis-related gene NADPH oxidase 4 (NOX4).

Methods

Male C57BL/6 mice underwent 45-minute middle cerebral artery occlusion (MCAO), followed by IPostC (three 15s/30s ischemia/reperfusion cycles after initial 2-minute reperfusion). RNA sequencing, combined with the least absolute shrinkage and selection operator (LASSO) and random forest machine learning, quantitative real-time PCR (qRT-PCR), infarct size measurement, and neurological tests, was used to identify ferroptosis-related genes and validate their roles in IPostC-induced neuroprotection.

Results

RNA sequencing revealed that 42 ferroptosis-associated differentially expressed genes underlie the neuroprotective effects of IPostC. Among them, NOX4 emerged as a central pathogenic regulator through LASSO and random forest machine learning analyses. IPostC reduced cerebral infarct size and improved foot-fault rate compared to MCAO mice. Notably, the ferroptosis inducer Erastin abolished the protective effects of IPostC. qRT-PCR validation revealed that IPostC downregulated NOX4 mRNA expression compared to MCAO controls, while Erastin upregulated NOX4 expression. In addition, pharmacological inhibition of NOX4 with GLX351322 reduced its mRNA expression, decreased infarct size, and improved neurological function, further confirming its critical role in mediating ferroptosis-driven brain injury after ischemic stroke.

Discussion

The inhibition of ferroptosis-associated gene NOX4 by IPostC may be a novel mechanism for treating ischemic stroke.

Conclusion

Our study indicates that IPostC attenuates cerebral ischemic injury by suppressing ferroptosis-associated gene NOX4.

Introduction

Olfactory epithelium (OE) comprises diverse cell types, including olfactory sensory neurons (OSNs), supporting cells, and basal stem cells. While interleukin (IL)-4 is a key mediator in type 2 inflammation, its regulatory role in OE remains unclear. The current study aimed to explore the role of IL-4 in olfactory epithelial cells.

Methods

Using an olfactory epithelial organoid model, the impacts of IL-4 on different cell types were assessed by performing qPCR, immunofluorescence staining, and EdU incorporation assays. Calcium imaging was performed to assess the influence of IL-4 on OSNs, while Alcian Blue-Periodic Acid-Schiff (AB-PAS) staining was used to analyze mucin secretion in the organoids.

Results

IL-4 significantly promoted the proliferation of globular basal cells (GBCs) in basal cells, induced homeostasis of mature OSNs, and maintained the normal function of OE. However, IL-4 notably downregulated GAP43 expression in immature OSNs. Additionally, IL-4 enhanced mucin secretion in the OE.

Discussion

This study found that IL-4 promoted the differentiation of OE cells by stimulating the proliferation of GBCs and enhancing mucin secretion, while maintaining the normal function of mature olfactory neurons. Further clinical studies are needed to validate these results.

Conclusion

This study revealed the role of IL-4 in OE, providing novel insights into the mechanisms of IL-4 in inflammatory conditions.

Introduction

Current genetic research on the relationship between hypertension and vertigo is limited, and traditional observational studies cannot establish a causal relationship due to design limitations, particularly regarding whether hypertension acts as a causal risk factor for specific vertigo subtypes, such as benign paroxysmal positional vertigo (BPPV).

Methods

This study employed a two-sample MR approach to infer causal relationships via genome-wide association study (GWAS) data, thereby addressing the limitations of traditional observational studies. In addition to analyzing the link between total vertigo and hypertension, we examined three major types of vertigo: central vertigo, benign paroxysmal positional vertigo (BPPV), and other peripheral vertigo. The study included 3834 cases of BPPV, 186 cases of central vertigo, 1293 cases of other peripheral vertigo, and 209,582 controls. Various MR methods, including the inverse variance weighted (IVW) approach, MR-Egger, weighted median, and simple mode, were employed to deduce the potential causative associations.

Results

A set of 53 genome-wide significant single-nucleotide polymorphisms (SNPs) associated with hypertension was identified as instrumental variables for subsequent MR analysis. The results indicated a significantly positive correlation between hypertension and the risk of total vertigo (OR: 1.16, 95% CI: 1.08-1.25, p <0.05), BPPV (OR: 1.12, CI: 1.01-1.24, and p =0.03), and other peripheral vertigo (OR: 1.19, 95% CI: 1.00-1.41, p =0.046), whereas no significant association was found with central vertigo (OR: 1.15, 95% CI: 0.74-1.80, p =0.53).

Discussion

This study provides genetic evidence for a positive association between hypertension and vertigo, particularly BPPV and peripheral vertigo, but not central vertigo. Hypertension may induce vestibular dysfunction via vascular changes leading to tissue hypoxia and cochlear-vestibular degeneration. Limitations include small sample sizes for certain vertigo subtypes (e.g., central vertigo) and limited generalizability to non-European populations.

Conclusion

This MR analysis provides evidence supporting a potential causal relationship between hypertension and an increased risk of certain types of vertigo. These findings contribute to the understanding of risk factors and the early prediction of vertigo.

Introduction

High On-Treatment Platelet Reactivity (HTPR) is frequently observed after carotid endarterectomy (CEA) or stenting (CAS), but its association with adverse events remains uncertain. This systematic review and meta-analysis evaluate the association between HTPR and recurrent vascular events in these patients.

Methods

EMBASE, PubMed, and Cochrane Library were searched for eligible studies from inception to July 1, 2024. Two independent reviewers screened the records, extracted data, and assessed the bias using predefined criteria. A meta-analysis was conducted using RevMan 5.4 software. The primary outcome was the risk of recurrent ischemic events in patients with HTPR. Secondary outcomes included the risk of hemorrhage and carotid restenosis.

Results

Eight studies involving 1,052 patients were included in the meta-analysis. This meta-analysis found that HTPR significantly increased the risk of adverse vascular events (OR = 2.41, 95% CI: 1.37-4.24), particularly in CAS patients (OR = 1.85, 95% CI: 1.14-2.98), but not in CEA patients (OR = 4.53, 95% CI: 0.52-39.12). Furthermore, HTPR was not significantly associated with an increased risk of bleeding (OR = 0.90, 95% CI: 0.24-3.37) or carotid restenosis (OR = 1.70, 95% CI: 0.38-7.55).

Discussion

This meta-analysis demonstrates that HTPR may increase the risk of recurrent ischemic events in CAS patients, supporting the clinical utility of platelet function monitoring in this population. However, no significant association was observed between HTPR and hemorrhage or restenosis. These findings should be interpreted cautiously due to study limitations, including small sample sizes and heterogeneity in platelet function assessment methodologies. Large-scale prospective studies with standardized protocols are warranted to validate these observations.

Conclusion

HTPR may be associated with an increased risk of recurrent ischemic events in patients undergoing CAS, highlighting the potential value of platelet function monitoring.

Introduction

Hemorrhagic stroke is a severe disease that endangers human life and well-being, with unclear pathogenesis. Recent studies have found an association between the immune system and hemorrhagic stroke, but the causal relationship between them remains unclear. We aim to elucidate the causal relationships between immune cell traits and hemorrhagic stroke using Mendelian randomization (MR).

Methods

We collected genome-wide association studies (GWAS) summary statistics for 731 immune cell traits as exposures, and GWAS data for hemorrhagic stroke outcomes, including intracerebral hemorrhage (ICH), subarachnoid hemorrhage (SAH), and cerebral aneurysm (non-ruptured) (CA), from the FinnGen Consortium's R10 dataset. Five methods were employed to evaluate the causal relationships, with the primary method being the inverse-variance weighted (IVW) method. Sensitivity analyses were carried out to enhance the robustness. Subsequently, we performed multivariate MR analyses, including confounding variables. Additionally, reverse MR analyses were carried out. Ultimately, we conducted pathway and functional enrichment analyses.

Results

After univariate and multivariate MR analyses, we identified that the higher counts of herpesvirus entry mediator (HVEM) on effector memory (EM) CD4+ cells (OR=0.954, 95%CI:0.925-0.984, P=0.003, PFDR=0.120) were a protective factor for SAH, and the counts of forward scatter area (FSC-A) on plasmacytoid dendritic cells (DC) (OR=1.059, 95%CI:1.023-1.095, P=0.001, PFDR=0.066) were associated with an increased risk of CA. The reverse MR indicated that CA could significantly increase the effector memory (EM) DN (CD4-CD8-) AC counts. No significant pleiotropy or heterogeneity was calculated in the MR analyses. SNP annotation and enrichment analyses suggested possible mechanisms by which immune cells affect hemorrhagic stroke.

Discussion

The involvement of immune cells in the neuroinflammatory responses has been demonstrated in previous studies. Among the immune cell traits with a significant causal relationship to hemorrhagic stroke, higher levels of HVEM on EM CD4+ cells may inhibit further inflammatory progress by binding to corresponding receptors, thereby exerting a protective effect against SAH. Alterations in FSC-A values (a flow cytometry measure of cell size) of plasmacytoid dendritic cells may contribute to atherosclerosis through cascading reactions that ultimately lead to CA. In addition, based on existing studies, other immune cell traits and related pathways identified in this study may contribute to the prevention and treatment of hemorrhagic stroke, providing a reference for future research. Finally, this study has some limitations, including population specificity, the use of a relatively lenient significance threshold (P < 1 × 10^-5), and potential bias from weak instrumental variables and pleiotropy.

Conclusion

This study demonstrated the causal relationships between immune cell traits and hemorrhagic stroke, laying the foundation for understanding the underlying mechanisms.

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