Increased interleukin-18 level contributes to the development and severity of ischemic stroke

The impact of cytokines in neuroinflammation-mediated stroke

Cerebral stroke is ranked as the third most common contributor to global mortality and disability. The involvement of inflammatory mechanisms, both peripherally and within the CNS, holds significance in the pathophysiological cascades following the initiation of stroke. After the onset of acute stroke, predominantly ischemic, a subsequent phase of neuroinflammation ensues. It is a dual-effect process that not only exacerbates injury, leading to cell death, but paradoxically, it also serves a shielding role in facilitating recovery. Cytokines serve as pivotal mediators within the inflammatory cascade, actively contributing to the progression of ischemic damage. Stroke is followed by increased expression of pro-inflammatory cytokines including TNF-α, IL-1β, IL-6, etc. leading to the recruitment and stimulation of glial cells and peripheral leukocytes at the site of injury, promoting neuroinflammation. Cytokines can directly induce neuronal injury and death through various mechanisms, including excitotoxicity, oxidative stress, HPA-axis activation, secretion of matrix metalloproteinase and apoptosis. They can also amplify the inflammatory response, leading to further neuronal damage. Therapeutic strategies aimed at modulating cytokine release, immune response and cytokine signalling or activity are being explored as potential interventions to mitigate neuroinflammation and its detrimental effects in stroke. In this review, we have given a concise summary of our current knowledge of the function of various cytokines, brain inflammation and various signalling and molecular pathways including JAK/STAT3, TGF-β/Smad, MAPK, HMGB1/TLR and NF-κB modulated cytokines regulation in stroke. Therapeutic agents such as MCC950, genistein, edaravone, minocycline, etc. targeting various cytokines-associated signalling pathways have shown efficacy in preclinical and clinical trials reducing the pathophysiology of the illness were also addressed in this study.

Targeting pyroptosis to treat ischemic stroke: From molecular pathways to treatment strategy

Ischemic stroke is the primary reason for human disability and death, but the available treatment options are limited. Hence, it is imperative to explore novel and efficient therapies. In recent years, pyroptosis (a pro-inflammatory cell death characterized by inflammation) has emerged as an important pathological mechanism in ischemic stroke that can cause cell death through plasma membrane rupture and release of inflammatory cytokines. Pyroptosis is closely associated with inflammation, which exacerbates the inflammatory response in ischemic stroke. The level of inflammasomes, GSDMD, Caspases, and inflammatory factors is increased after ischemic stroke, exacerbating brain injury by mediating pyroptosis. Hence, inhibition of pyroptosis can be a therapeutic strategy for ischemic stroke. In this review, we have summarized the relationship between pyroptosis and ischemic stroke, as well as a series of treatments to attenuate pyroptosis, intending to provide insights for new therapeutic targets on ischemic stroke.

Exploring causal association between circulating inflammatory cytokines and functional outcomes following ischemic stroke: A bidirectional Mendelian randomization study

OBJECTIVES

Previous observational studies have indicated correlations between various inflammatory cytokines and functional outcomes following ischemic stroke (IS); however, the causality remains unclear. We aimed to further evaluate the causal association between 41 circulating inflammatory cytokines and functional outcomes following IS.

METHODS

Two-sample bidirectional Mendelian randomization (MR) analysis was used in this study. The genetic variation of 41 circulating inflammatory cytokines were derived from genome-wide association study (GWAS) data of European ancestry (n = 8293). The corresponding genetic association of functional outcomes following IS were derived from European ancestry GWAS data (n = 6021).

RESULTS

Inverse variance weighted (IVW) analysis showed that genetically predicted increased levels of regulation and activation in normal T-cell expression and secretion factor (RANTES/CCL5) and eosinophilic chemotactic factor (EOTAXIN/CCL11) were positively correlated with the increased adverse functional outcomes (modified Rankin Scale [mRS≥3] following IS (OR: 1.40, 95% CI: 1.002-1.96, p = 0.049; OR: 1.33, 95% CI: 1.15-1.54, p = 0.0001). Interleukin 18 (IL-18) level might be the downstream consequence of adverse functional outcomes following IS (β: -0.09, p = 0.039). Other inflammatory cytokines and functional outcomes following IS did not appear to be causally related.

CONCLUSIONS

This study suggests a causality between inflammation and adverse functional outcomes following IS. RANTES (CCL5) and EOTAXIN (CCL11) may be the upstream factors of adverse functional outcomes following IS, while IL-18 may be the downstream effect of adverse functional outcomes following IS. Whether these cytokines can be used to predict or improve adverse functional outcomes after IS requires further researches.

Investigating the Potential Mechanisms and Therapeutic Targets of Inflammatory Cytokines in Post-stroke Depression

Post-stroke depression (PSD) affects approximately one-third of stroke survivors, severely impacting general recovery and quality of life. Despite extensive studies, the exact mechanisms underlying PSD remain elusive. However, emerging evidence implicates proinflammatory cytokines, including interleukin-1β, interleukin-6, tumor necrosis factor-alpha, and interleukin-18, play critical roles in PSD development. These cytokines contribute to PSD through various mechanisms, including hypothalamic-pituitary-adrenal (HPA) axis dysfunction, neurotransmitter alterations, neurotrophic factor changes, gut microbiota imbalances, and genetic predispositions. This review is aimed at exploring the role of cytokines in stroke and PSD while identifying their potential as specific therapeutic targets for managing PSD. A more profound understanding of the mechanisms regulating inflammatory cytokine expression and anti-inflammatory cytokines like interleukin-10 in PSD may facilitate the development of innovative interventions to improve outcomes for stroke survivors experiencing depression.

ASIC1a-CMPK2-mediated M1 macrophage polarization exacerbates chondrocyte senescence in osteoarthritis through IL-18

PURPOSE

Identification of a role for, and the mechanism of action of, the acid-sensing ion channel 1a (ASIC1a) in M1 macrophage polarization, which results in osteoarthritis (OA)-associated chondrocyte senescence.

METHOD

ASIC1a expression in synovial M1 macrophages of OA patients was assessed by immunofluorescence. A role for ASIC1a in M1 macrophage and chondrocyte senescence was assessed in a mouse OA model.

RESULTS

ASIC1a expression was found to be upregulated in synovial M1 macrophages of OA patients. Extracellular acidification (pH 6.0) promoted M1 polarization of bone marrow derived macrophages (BMDMs), which was reversed by PcTx-1 or ASIC1a-siRNA. RNA-seq transcriptome results demonstrated a downregulation of M1 macrophage-associated genes in BMDMs after PcTx-1 treatment. Mechanistically, a role for the ASIC1a-cytidine/uridine monophosphate kinase 2 (CMPK2) axis in M1 macrophage polarization was demonstrated. The concentration of IL-18 was elevated in synovial fluid and supernatants of acid-activated BMDMs. In vitro, IL-18 stimulation or co-culture with acid-activated macrophages promoted chondrocyte senescence. In vivo, intra-articular administration of PcTx-1 reduced articular cartilage destruction and chondrocytes senescence in OA mice, which related to reduced numbers of M1 macrophages and IL-18 in affected joints.

CONCLUSION

These results demonstrate a novel pathogenic process that results in OA cartilage damage, in which M1 macrophage derived IL-18 induces articular chondrocytes senescence. Further, the ASIC1a-CMPK2 axis was shown to positively regulate M1 macrophage polarization. Hence, ASIC1a is a promising treatment target for M1 macrophage-mediated diseases, such as OA.

Gut microbiota composition reflects disease progression, severity and outcome, and dysfunctional immune responses in patients with hypertensive intracerebral hemorrhage

OBJECTIVE

In this study, we aimed to explore the alterations in gut microbiota composition and cytokine responses related to disease progression, severity, and outcomes in patients with hypertensive intracerebral hemorrhage (ICH).

METHODS

Fecal microbiota communities of 64 patients with ICH, 46 coronary heart disease controls, and 23 healthy controls were measured by sequencing the V3-V4 region of the 16S ribosomal RNA (16S rRNA) gene. Serum concentrations of a broad spectrum of cytokines were examined by liquid chips and ELISA. Relationships between clinical phenotypes, microbiotas, and cytokine responses were analyzed in the group with ICH and stroke-associated pneumonia (SAP), the major complication of ICH.

RESULTS

In comparison with the control groups, the gut microbiota of the patients with ICH had increased microbial richness and diversity, an expanded spectrum of facultative anaerobes and opportunistic pathogens, and depletion of anaerobes. Enterococcus enrichment and Prevotella depletion were more significant in the ICH group and were associated with the severity and functional outcome of ICH. Furthermore, Enterococcus enrichment and Prevotella depletion were also noted in the SAP group in contrast to the non-SAP group. Enterococci were also promising factors in the prognosis of ICH. The onset of ICH induced massive, rapid activation of the peripheral immune system. There were 12 cytokines (Eotaxin, GM-CSF, IL-8, IL-9, IL-10, IL-12p70, IL-15, IL-23, IL-1RA, IP-10, RANTES, and TNF-α) changed significantly with prolongation of ICH, and the Th2 responses correlated with the 90-day outcomes. Cytokines TNF-α, IP-10, IL-1RA, IL-8, IL-18, and MIP-1β in SAP group significantly differed from non-SAP group. Among these cytokines, only IP-10 levels decreased in the SAP group. Enterococcus was positively associated with IL-1RA and negatively associated with IP-10, while Prevotella was inversely associated in both the ICH and SAP groups.

CONCLUSION

This study revealed that gut dysbiosis with enriched Enterococcus and depleted Prevotella increased the risk of ICH and subsequently SAP. The altered gut microbiota composition and serum cytokine profiles are potential biomarkers that reflect the inciting physiologic insult/stress involved with ICH.

Interleukin-18 mediated inflammatory brain injury after intracerebral hemorrhage in male mice

Interleukin-18 (IL-18), a pro-inflammatory cytokine, is thought to be associated with inflammation in many neurological diseases such as ischemic stroke and poststroke depression, but the role of IL-18 in inflammatory injury after intracerebral hemorrhage (ICH) remains unclear. In this study, we established the ICH model in male mice and found that IL-18 expression including protein and mRNA levels was significantly increased in brain tissues after ICH. Meanwhile, exogenous IL-18 exacerbated cerebral hematoma and neurological deficits following ICH. In the IL-18 knockout group, the size of hematoma and neurological functions after ICH was decreased compared with the wild-type group, suggesting the critical role of IL-18 on the modulation of brain injury after ICH. Importantly, exogenous IL-18 increased microglial activation in brain tissues after ICH. Furthermore, IL-18 knockout resulted in the reduction of activated microglia after ICH. These results indicated that IL-18 may regulate the inflammatory response after ICH through the activation of microglia. Thus, IL-18 is expected to be a promising therapeutic target for secondary brain injury after ICH.

Vagus nerve stimulation alleviated cerebral ischemia and reperfusion injury in rats by inhibiting pyroptosis via α7 nicotinic acetylcholine receptor

Cumulative evidence suggests that pyroptosis, a new sort of programmed cell death, is closely related to cerebral ischemia/reperfusion (I/R) injury. Our previous studies have testified that vagus nerve stimulation (VNS) was involved in many different neuroprotective and neuroplasticity pathways via α7 nicotinic acetylcholine receptor (α7nAchR), a vital node of the cholinergic anti-inflammatory pathway during cerebral I/R injury. We aimed to determine the neuroprotective effects of VNS through α7nAchR-mediated inhibition of pyroptosis. Focal cerebral ischemic stroke rat models were obtained by middle cerebral artery occlusion for 120 min. Expression of the NLRP3 inflammasome was evaluated using western blotting and immunofluorescence (IF) staining. The neurological deficit score, infarct volume, TUNEL staining findings, transmission electron microscopy findings, and expression of inflammatory cytokines were assessed 3 days after I/R injury. Our findings suggested that the protein expression levels of NLRP3, GSDMD-N, cleaved caspase-1, and ASC gradually increased until they peaked on day 3 after I/R injury. VNS inhibited the expression of pyroptosis-related molecules and decreased the number of pyroptotic cells and membrane pores. Administration of α7nAchR-antagonist and agonist helped in further assessment of the role of α7nAchR in pyroptosis. α7nAchR-agonist mimicked VNS’s neuroprotective effects on the improvement of neurological deficits, the reduction of infarct volumes, and the inhibition of neuronal pyroptosis after cerebral I/R injury. Conversely, the neuroprotection provided by VNS could be reversed by the administration of α7nAchR-antagonist. In conclusion, VNS-induced neuroprotection via inhibition of neuronal pyroptosis was α7nAchR-dependent, highlighting the pivotal role of α7nAChR in suppressing cellular pyroptosis and neuroinflammation. These findings may allow a better understanding of treatment principles for cerebral I/R injury.

Elevated Red Blood Cell Distribution Width Levels at Admission Predicts Depression After Acute Ischemic Stroke: A 3-Month Follow-Up Study

PURPOSE

Red blood cell distribution width (RDW) is closely related to inflammatory-related disease markers. The present study aimed to investigate the association between the red blood cell distribution width (RDW) and post-stroke depression (PSD).

PATIENTS AND METHODS

A total of 414 patients with acute ischemic stroke (AIS) admitted to our hospital from June 2018 to July 2021 were consecutively enrolled and received 3 months' follow-up. According to the 17-item Hamilton Depression Scale (HAMD) assessment, they were divided into PSD group and non-PSD group. Diagnosis of PSD was made in accordance with DSM-IV. RDW was recorded within 24 hours of admission.

RESULTS

Among the included 414 patients, 95 (22.95%) patients were diagnosed as having PSD at 3 months after stroke. The results showed significantly higher level of RDW in patients with depression (13.69 (IQR13.24-13.88) vs. 13.56 (IQR 12.67-13.77), P<0.001) at admission than patients without depression. After adjustment for potential confounding factors, the odds ratio of PSD was 5.707 (95% CI, 2.717-11.989) for the highest tertile of RDW compared with the lowest tertile. Moreover, based on the receiver operating characteristic (ROC) curve, the optimal cutoff of RDW levels as an indicator for the prediction of PSD was projected as 13.01, which yielded a sensitivity of 83% and a specificity of 41.0%, with an area under the curve (AUC) of 0.643 (95% CI, 0.585-0.701; P = 0.012).

CONCLUSION

Higher RDW levels at admission were found to be correlated with PSD 3 months after stroke.

Acute Inflammation in Cerebrovascular Disease: A Critical Reappraisal with Focus on Human Studies

Recent attention has been focused on the field of inflammatory biomarkers associated with vascular disorders, regarding diagnosis, prognosis, and possible therapeutical targets. In this study, we aimed to perform a comprehensive review of the literature regarding the use of inflammatory biomarkers in stroke patients. We searched studies that evaluated inflammation biomarkers associated with Cerebrovascular Disease (CVD), namely, ischemic Stroke (IS), Intracerebral Hemorrhage (ICH) and Cerebral Venous Thrombosis (CVT). As of today, neutrophil–lymphocyte ratio (NLR) seems the be the most widely studied and accepted biomarker for cerebrovascular disease due to its easy access and availability. Although demonstrated as a prognostic risk factor, in IS, ICH and CVT, its diagnostic role is still under investigation. Several other prognostic factors could be used or even combined together into a diagnostic or prognostic index. Multiple inflammatory biomarkers appear to be involved in IS, ICH, and CVT. Blood inflammatory cells, easily measured and accessible at admission may provide information regarding accurate diagnosis and prognosis. Although not yet a reality, increasing evidence exists to suggest that these may become potential therapeutic targets, likely influencing or mitigating complications of CVD and improving prognosis. Nevertheless, further larger, well-designed randomized clinical trials are still needed to follow up this hypothesis.

Spata2 Knockdown Exacerbates Brain Inflammation via NF-κB/P38MAPK Signaling and NLRP3 Inflammasome Activation in Cerebral Ischemia/Reperfusion Rats

Brain inflammation induced by ischemic stroke is an important cause of secondary brain injury. The nuclear factor kappa B (NF-κB), mitogen-activated protein kinase (MAPK), and NLRP3 inflammasome signaling are believed to drive the progression of brain inflammation. Spermatogenesis-associated protein2 (SPATA2) functions as a partner protein that recruits CYLD, a negative regulator of NF-κB signaling, to signaling complexes. However, the role of SPATA2 in the central nervous system remains unclear and whether it is involved in regulating inflammatory responses remains controversial. Rats were subjected to transient middle cerebral artery occlusion followed by reperfusion (tMCAO/R) surgery. The expression and localization of SPATA2 in the brain were investigated. The lentivirus-mediated shRNA was employed to inhibit SPATA2 expression. The inflammatory responses and outcomes of Spata2 knockdown were investigated. SPATA2 was co-localized with CYLD in neurons. SPATA2 expression was reduced in tMCAO/R rats. Spata2 knockdown resulted in increased microglia, increased expression of Tnfa, Il-1β, and Il-18, decreased Garcia score, and increased infarct volume. Spata2 knockdown resulted in the activation of P38MAPK and NLRP3 inflammasome and the increased activation of NF-κB signaling. These results suggest that SPATA2 plays a protective role against brain inflammation induced by ischemia/reperfusion injury. Therefore, SPATA2 could be a potential therapeutic target for treating 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.

The Role of Interleukin-18 in the Development and Progression of Atherosclerosis

Atherosclerosis (AS), as a chronic inflammatory disorder of the cardiovascular system, is one of the leading causes of ischemic heart disease, stroke and peripheral vascular disease. There is growing evidence on the role of innate and adaptive immunity in the pathogenesis of atherosclerosis. Interleukin-18 is one of the novel proinflammatory cytokines involved in atherogenesis, atherosclerotic plaque instability and plaque rupture. In this review, we overview the findings of preclinical and clinical studies about the role and mechanism of action of IL-18 in the pathogenesis of AS, which could offer novel prognostic and therapeutic approaches.

Vinpocetine Attenuates Ischemic Stroke Through Inhibiting NLRP3 Inflammasome Expression in Mice

ABSTRACT

Ischemic stroke is the leading cause of globe death and permanent disability, but its therapeutic strategies are limited. Over the past decades, multiprotein complexes called inflammasomes have been shown as promising targets in ischemic stroke. Here, we examined vinpocetine (Vinp), a synthetic drug, playing a neuroprotective role against ischemic stroke in mice through regulating NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation. Middle cerebral artery occlusion/reperfusion (MCAO/R) was applied to mimic ischemic stroke in vivo. Vinp was administrated by intraperitoneal injection with different dose (5 or 10 mg/kg) 1 hour after reperfusion. Then, neurological assessment and infarct size were performed, and interleukin-1β (IL-1β) and IL-18 levels were evaluated using ELISA. The levels of NLRP3 inflammasome components and its upstream nuclear factor-κB (NF-κB) were determined using real-time PCR or Western blot. The experimental results indicated that posttreatment with Vinp decreased cerebral infarct size, improved behavior recover, reduced NLRP3 inflammasome expression, and suppressed the transfer of NF-κB to nucleus and proinflammatory cytokine release in middle cerebral artery occlusion/reperfusion mice. In conclusion, this study demonstrates that Vinp alleviates ischemic stroke by regulating levels of NLRP3 inflammasome, NF-κB, and proinflammatory cytokines in vivo, offering an alternative medication for ischemic stroke associated with inflammation.

Neuroinflammation evoked by brain injury in a rat model of lacunar infarct

Stroke is the leading cause of long-term, severe disability worldwide. Immediately after the stroke, endogenous inflammatory processes are upregulated, leading to the local neuroinflammation and the potentiation of brain tissue destruction. The innate immune response is triggered as early as 24 h post-brain ischemia, followed by adaptive immunity activation. Together these immune cells produce many inflammatory mediators, i.e., cytokines, growth factors, and chemokines. Our study examines the immune response components in the early stage of deep brain lacunar infarct in the rat brain, highly relevant to the clinical scenario. The lesion was induced by stereotactic injection of ouabain into the adult rat striatum. Ouabain is a Na/K ATPase pump inhibitor that causes excitotoxicity and brings metabolic and structural changes in the cells leading to focal brain injury. We have shown a surge of neurodegenerative changes in the peri-infarct area in the first days after brain injury. Immunohistochemical analysis revealed early microglial activation and the gradual infiltration of immune cells with a significant increase of CD4⁺ and CD8⁺ T lymphocytes in the ipsilateral hemisphere. In our studies, we identified the higher level of pro-inflammatory cytokines, i.e., interleukin-1α, interleukin-1β, tumor necrosis factor-α, and interferon-γ, but a lower level of anti-inflammatory cytokines, i.e., interleukin-10 and transforming growth factor-β2 in the injured brain than in normal rats. Concomitantly focal brain injury showed a significant increase in the level of chemokines, i.e., monocyte chemoattractant protein-1 and CC motif chemokine ligand 5 compared to control. Our findings provide new insights into an early inflammatory reaction in our model of the deep-brain lacunar infarct. The results of this study may highlight future stroke immunotherapies for targeting the acute immune response accompanied by the insult.

Interleukin-18 from neurons and microglia mediates depressive behaviors in mice with post-stroke depression

Post-stroke depression (PSD) is a common and serious complication that is affecting one thirds of stroke patients which leaves them with a poor quality of life, high mortality rate, high recurrent rate, and slow recovery. Recent studies showed that serum interleukin-18 (IL-18) level is a biomarker for patients with PSD. However, the role of IL-18 in the pathology of PSD is still unclear. In this study, we demonstrated that the IL-18 level in the ischemic brain significantly increased in mice with depression-like behaviors that were caused by the combined use of chronic spatial restraint stress and middle cerebral artery occlusion. Interestingly, IL-18 expression was mainly found in neurons at early phase and in microglia at a later phase. Injection of the exogenous IL-18 into the amygdala, but not the hippocampus or the striatum caused severe depression-like behaviors. On the contrary, the blockage of endogenous IL-18 by IL-18 binding protein, a specific antagonist of IL-18, repressed depressive phenotypes in SIR mice. IL-18 KO mice exhibited the resistance to spatial restraint stress and cerebral ischemia injury. Finally, we found that IL-18 mediated depressive behaviors by the interaction of IL-18 receptor and NKCC1, a sodium-potassium chloride co-transporter that is related to GABAergic inhibition. Administration of NKCC1 antagonist bumetanide exerted a therapeutic effect on the in IL-18-induced depressive mice. In conclusion, we demonstrated that increased IL-18 in the brain causes depression-like behaviors by promoting the IL-18 receptor/NKCC1 signaling pathway. Targeting IL-18 and its downstream pathway is a promising strategy for the prevention and treatment of PSD.

Neuroinflammation and fibrosis in stroke: The good, the bad and the ugly

Stroke is the leading cause of death and the main cause of disability in surviving patients. The detrimental interaction between immune cells, glial cells, and matrix components in stroke pathology results in persistent inflammation that progresses to fibrosis. A substantial effort is being directed toward understanding the exact neuroinflammatory events that take place as a result of stroke. The initiation of a potent cytokine response, along with immune cell activation and infiltration in the ischemic core, has massive acute deleterious effects, generally exacerbated by comorbid inflammatory conditions. There is secondary neuroinflammation that promotes further injury, resulting in cell death, but conversely plays a beneficial role, by promoting recovery. This highlights the need for a better understanding of the neuroinflammatory and fibrotic processes, as well as the need to identify new mechanisms and potential modulators. In this review, we summarize several aspects of stroke-induced inflammation, fibrosis, and include a discussion of cytokine inhibitors/inducers, immune cells, and fibro-inflammation signaling inhibitors in order to identify new pharmacological means of intervention.

Red blood cell distribution width is associated with neuronal damage in acute ischemic stroke

Elevated red blood cell distribution width (RDW) has been found to be associated with the occurrence of ischemic stroke. However, there is no defined relationship between RDW and neuronal damage in acute ischemic stroke (AIS). This study was designed to determine the relationship between RDW and neuronal damage in AIS patients. A total of 442 consecutive AIS patients from January 2018 to June 2019 were evaluated for neuronal damage, which was estimated by serum neuron-specific enolase (NSE) levels. Red blood cell distribution width-standard deviation (RDW-SD), a parameter that reflects the heterogeneity of red blood cell volume, was also assessed. We evaluated the association between the RDW-SD and serum NSE level through multivariate-adjusted linear regression analysis. Both the serum NSE level and the incidence of high NSE increased according to the increased RDW-SD tertile in AIS patients (p<0.01). There was a positive correlation between RDW-SD and serum NSE levels (r=0.275, 95% CI: 0.187-0.359, p<0.001). The beta coefficients (95% CI) between RDW-SD and serum NSE levels were 0.32 (0.21-0.42, p<0.001) and 0.26 (0.15-0.38, p<0.001), respectively, in AIS patients before and after adjusting for potential confounders. In conclusion, we found a significant positive association between RDW-SD and neuronal damage in AIS patients.

Neuroprotective Effects of Qingnao Dripping Pills Against Cerebral Ischemia via Inhibiting NLRP3 Inflammasome Signaling Pathway: In Vivo and In Vitro

Ischemic stroke patients suffer from relatively limited treatment options. Studies have shown that in cerebral ischemia, NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is a key mediator in mediating inflammatory responses and results in activation of apoptosis signaling pathways. Here we assessed the in vivo and in vitro effects of Qingnao Dripping Pills (QNDP), a traditional Chinese prescription, on inflammatory responses and apoptosis. Our results showed that QNDP could significantly decrease cerebral ischemia injury, improve neurological function and inhibit apoptosis in rats impaired by middle cerebral artery occlusion (MCAO). Further, we found that QNDP inhibited NLRP3 inflammasome expression both in MCAO rats and in SH-SY5Y cells under OGD. Moreover, the levels of inflammatory cytokines including interleukin-1β (IL-1β) and IL-18, which mediated by NLRP3 inflammasome and increased in MCAO rats, could be reduced by QNDP, suggesting that QNDP could protect the neurons against inflammation through a mechanism mediated by NLRP3 inflammasome. Nuclear factor-kappa B (NF-κB) was also involved in the anti-inflammatory effect of QNDP. In conclusion, QNDP had neuroprotective effects against cerebral ischemia via inhibiting NLRP3 inflammasome signaling pathway, and was a potential candidate for the future treatment of ischemic stroke.