Targeting inflammation to reduce recurrent stroke

Targeting to miR-130b-5p/TLR4: How sodium danshensu suppresses inflammatory response of microglia in cerebral ischemia-reperfusion injury

Cerebral ischemia reperfusion injury (CIRI) is a crucial process in the inflammatory response. Sodium danshensu (SDSS) is of protective effects in cardiovascular and cerebrovascular diseases due to its anti-inflammatory properties. Studies have demonstrated that SDSS administration reduces infarct volume, attenuates neurological impairment, and inhibits microglia activation in rat models of CIRI. While it is well established that miRNAs play roles in a wide range of diseases through multiple pathways. However, the mechanism by which SDSS alleviates inflammatory injury after CIRI and its potential interaction with miRNAs remain unclear. Thus, we aimed to investigate the effectiveness and mechanism of SDSS in CIRI, and to verify whether it exerts anti-inflammatory effects by affecting miRNA. Through bioinformatics analysis and experimental validation, we identified miR-130b-5p is a key gene in the CIRI process, with SDSS administration leading to an upregulation of miR-130b-5p that is indispensable for its anti-inflammatory effects. Moreover, both SDSS and miR-130b-5p reduced the expression of TLR4. Overall, the beneficial effects of SDSS on CIRI can be attributed to the up-regulation of miR-130b-5p and the inhibition of TLR4, resulting in the attenuation of the inflammatory response.

Effect of atrial fibrosis on clot burden score and physicochemical properties of thrombus in patients with ischaemic stroke occurring in non-valvular atrial fibrillation

Background

To investigate the effect of the degree of atrial fibrosis on the clot burden score (CBS) and physicochemical properties in patients with acute ischaemic stroke (AIS) due to non-valvular atrial fibrillation (NVAF).

Methods

A total of 117 patients with AIS in NVAF attending the Department of Cardiovascular Medicine and the Cerebrovascular Diagnostic and Treatment Centre between August 2021 and May 2024 were included in the study. Baseline clinical data, biochemical indexes, and imaging data of the patients were collected, and the patients were divided into 93 cases of the CBS (score of 0-6) group and 24 cases of the CBS (score of 7-10) group according to the CBS. CBS (score of 0-6) signifies higher clot burden. The enzyme-linked immunosorbent assay was used to measure the concentration of galactaglutinin-3 (gal-3) and transforming growth factor (TGF-β1) in the serum of the patients, and the PTFV1 were collected by 12-lead electrocardiogram, and the differences in the degree of atrial fibrosis between different groups and the risk factors of CBS (score of 0-6) were analysed. To analyse the effect of atrial fibrosis on the collateral circulation of stroke, the patients were divided into 31 cases with good collateral circulation (grade 3-4) and 86 cases with poor collateral circulation (grade 0-2) according to the digital subtraction angiography (DSA) images. The cerebral thrombus was collected from 60 AIS patients who underwent mechanical thrombectomy. The content of erythrocyte, fibrin/platelets and leukocytes in the thrombus was analysed by Mathew's scarlet blue staining, and the density of thrombus was measured by computed tomography (CT).

Results

A total of 117 patients were included in this study, and the proportion of hypertensive patients, proportion of chronic atrial fibrillation (CAF), B-type natriuretic peptide (BNP), neutrophil/lymphocyte ratio (NLR), D-dimer, uric acid concentration, proportion of patients with PTFV1 < -0.03 mm s, gal-3, and TGF-β1 were higher in the CBS (score of 0-6) group as compared to the CBS (score of 7-10) group (P-value < 0.05). Hypertension, proportion of CAF, homocysteine, NLR, D-dimer, uric acid, PTFV1 < -0.03 mm s, gal-3, and TGF-β1, were risk factors for the development of high CBS in atrial fibrillation (AF), and hypertension and CAF were the most important factors for the occurrence of AF in the independent risk factors for stroke combined with high clot burden. gal-3 and TGF-β1 were risk factors for poor collateral circulation, atrial fibrosis indexes were not associated with thrombus pathological composition and thrombus density.

Conclusions

Atrial fibrosis increases clot burden in patients with AIS due to NVAF but does not significantly correlate with the physicochemical properties and density of the thrombus.

C-reactive protein expression in acute ischemic stroke blood clots: Implications for etiology

INTRODUCTION

C-reactive protein (CRP) is a prototypic inflammation marker, with elevated levels associated with an increased risk of cerebrovascular events. To determine whether CRP could be a useful biomarker of stroke etiology, we investigated CRP expression in acute ischemic stroke (AIS) clots from large-artery atherosclerosis (LAA), cardio-embolism (CE) and cryptogenic (Crypt) subtypes.

PATIENTS AND METHODS

We analysed clot samples from AIS patients (LAA, CE, Crypt; n = 50 each), collected across five stroke centres in France, Serbia, Spain, and Japan between February 2021 and February 2024, as part of the prospective Clotbase International Registry of 460 patients who underwent mechanical thrombectomy. Clot components were assessed using Martius Scarlet Blue staining. CRP expression was examined using immunohistochemistry and its co-localisation with clot components was detected using immunofluorescence. Clinical parameters were compared across etiologies.

RESULTS

CRP expression varied significantly among clots. Most clots (65%) had minimal (⩽1%) CRP and 35% showed substantial (>1%) CRP. CE group had significantly more clots with substantial CRP than LAA and Crypt (48% vs 30% and 26%; p = 0.048). Clots with substantial CRP contained more fibrin (28.9%) than those with low CRP (20.6%; p = 0.005). Confocal microscopy showed CRP co-localised with fibrin and white blood cells (WBCs).

DISCUSSION AND CONCLUSION

Significantly more AIS clots of CE expressed substantial CRP compared to those of LAA and Crypt, suggesting CE strokes may be more strongly linked to inflammation. Clots with substantial CRP expression displayed significantly more fibrin compared to those with minimal CRP expression, suggesting a potential association between inflammation and fibrin-rich clots. Further study of the relationship between CRP, fibrin and WBCs in clots may improve our understanding of the processes of thrombo-inflammation.

Intranasal delivery of hMSC-derived supernatant for treatment of ischemic stroke by inhibiting the pro-inflammatory polarization of neutrophils

BACKGROUND

Stem cells utilized for ischemic stroke treatment often display unstable homing capabilities and diminished activity in vivo, limiting their neuroprotective efficacy. Furthermore, the optimal delivery route for stem cells remains undetermined. While the cytokines secreted by stem cells show promise in modulating post-stroke inflammation, the direct application of these supernatants in ischemic stroke treatment and the underlying mechanisms are still unclear.

METHODS

Secretory supernatants (hMSC-L) and cell lysate products (hMSC-M) from primary human umbilical cord mesenchymal stem cells-cultured medium were administered intranasally to mice with cerebral ischemia. The neuroprotective effects of hMSC-L and hMSC-M were assessed with TTC staining, behavioral tests and pathological staining. Flow cytometry and qPCR evaluated the expression of immune cells and cytokines in the CNS and peripheral immune organs. In vitro, flow cytometry and ELISA measured the effects of hMSC-L and hMSC-M on N2 polarization and inflammatory cytokines expression in primary murine neutrophils. Western blot analysis determined the impact of hMSC-L and hMSC-M on the PPAR-γ/STAT6/SOCS1 pathway, which is crucial for N2 neutrophil polarization.

RESULTS

TTC staining, behavioral experiments, and pathological assessments reveal intranasal delivery of hMSC-L and hMSC-M significantly reduces the infarct volume of mice with cerebral ischemia, improves neurological function scores, and promotes motor function recovery. Higher concentrations of hMSC-M contributed a more pronounced effect on neuropathological improvements in ischemic mice. Intranasal delivery of hMSC-L and hMSC-M significantly reduces neutrophil infiltration in the brain post-stroke and increases the proportion of anti-inflammatory N2-subtype neutrophils, boosting the expression levels of IL-10 and TGF-β. In vitro experiments demonstrate that hMSC-L and hMSC-M promote nuclear translocation of PPAR-γ in neutrophils stimulated with PMA, activating the downstream STAT6/SOCS1 signaling pathway to encourage N2-subtype neutrophil polarization.

CONCLUSIONS

Intranasal delivery of hMSC-L and hMSC-M effectively ameliorates cerebral ischemic injury in mice, comparable to traditional administration routes like intravenous delivery. Treatment with hMSC-L and hMSC-M enhances the PPAR-γ/STAT6/SOCS1 pathway and improves the neuroinflammatory response post-stroke by increasing N2 neutrophil infiltration. These results provide a theoretical basis for a deeper understanding of the mechanisms of stem cell therapy and for exploring suitable delivery pathways of stem cell treatment.

Systemic Immune-Inflammation Index (SII) and Neutrophil-to-Lymphocyte Ratio (NLR): A Strong Predictor of Disease Severity in Large-Artery Atherosclerosis (LAA) Stroke Patients

Background

Systemic immune-inflammation index (SII) and neutrophil-to-lymphocyte ratio (NLR) are novel inflammatory markers based on neutrophil, platelet and lymphocyte counts. Atherosclerosis is a chronic inflammatory vascular disease. This study aimed to verify the predictive value of the clinical parameters such as systemic immune-inflammation index (SII) and neutrophil-to-lymphocyte ratio (NLR) for the severity in Large Artery Atherosclerosis (LAA) stroke patients.

Methods

The SII is defined as platelet × (neutrophil count/lymphocyte count), the NLR is defined as neutrophil count/lymphocyte count. Univariate logistic regression was used to analyze the association between SII and NLR and NIHSS score in patients with LAA stroke. Multiple logistic regression was used to analyze the risk factors for the severity of LAA stroke. We plotted receiver operating characteristic curves to determine the diagnostic role of SII and NLR in differentiating stroke disease severity.

Results

We included 283 LAA stroke patients, the SII and NLR in the moderate-to-severe stroke group were significantly higher than the mild stroke group. Multiple logistic regression analysis showed that SII (OR 1.051 95% CI (1.035-1.066), P < 0.001), NLR (OR 1.077,95% CI (1.032-1.123), P < 0.001) were significantly associated with stroke severity. The SII values under the receiver operating characteristic curve (0.701, 95% CI (0.649-0.791, P < 0.001, cut-off value 912.97) and NLR values under the receiver operating characteristic curve (0.604,5% CI (0.519-0.689), P < 0.01, cut-off value 1.461), and SII values had high discrimination ability. Both SII and NLR had high diagnostic and predictive value for stroke severity, and SII was better than NLR.

Conclusion

The higher SII and NLR, the more severity in LAA stroke patients. SII and NLR are independent risk factors for LAA stroke, and they can also effectively predict stroke severity; moreover, SII has a higher diagnostic efficacy than NLR. However, multicenter studies with large sample size are still needed to confirm this conclusion.

Carotid endarterectomy and the risk of perioperative stroke: The importance of chronic ischaemic lesions and small vessel disease

BACKGROUND AND PURPOSE

Perioperative stroke is a well-recognized complication of carotid endarterectomy (CEA), but well-performing prediction models do not exist for it. Our aim was to identify novel predictors for perioperative ischaemic cerebrovascular events (iCVEs), emphasizing cerebrovascular imaging and potential biomarkers for stroke in carotid stenosis (CS) patients in a well-characterized prospective CS cohort.

METHODS

Helsinki Carotid Endarterectomy Study 2 is an observational prospective and consecutive cohort study of CS patients subjected to CEA during 2012-2015. The associations between perioperative stroke and transient ischaemic attack (iCVEs) and potential predictive factors were evaluated by univariate and Cox regression analyses.

RESULTS

Of 488 operated CS patients, 33 (7%) sustained an iCVE including 21 (4%) ischaemic strokes. In univariate analysis, moderate ipsilateral CS (hazard ratio [HR] 2.14, 95% confidence interval [CI] 1.08-4.23), covert or chronic ipsilateral brain infarct in imaging (HR 2.27, 95% CI 1.09-4.76) and severe cerebral small vessel disease (HR 3.36, 95% CI 1.04-10.88) appeared as novel risk factors for perioperative iCVE. In Cox proportional hazards regression modelling, female gender (HR 3.03, 95% CI 1.30-7.04), a history of coronary heart disease (HR 3.59, 95% CI 1.52-8.47), covert or chronic ipsilateral infarct (HR 2.32, 95% CI 1.01-5.34) and severe small vessel disease (HR 2.63, 95% CI 1.07-6.47) were the strongest independent predictors of perioperative iCVE.

CONCLUSIONS

In addition to the previously reported clinical risk factors, it was found that imaging markers of past cerebrovascular disease, covert or chronic ipsilateral infarct and severe small vessel disease, and moderate ipsilateral stenosis are associated with perioperative iCVEs.

Rationale and design of the efficacy and safety of combination of cilostazol and gingko biloba extract EGb 761 in patients with acute non-cardioembolic ischemic stroke (RENEW): A pilot and feasibility randomized controlled trial

BACKGROUND

Dual antiplatelet therapy with aspirin and clopidogrel is the standard treatment for acute ischemic stroke (AIS). Cilostazol has emerged as a safe alternative with pleiotropic effects that prevent stroke without increasing the risk of bleeding and has been shown to reduce neurological deterioration (ND) in the acute phase. Ginkgo biloba extract (EGb 761) has also been reported to improve neurological impairment following AIS. This trial aimed to evaluate the efficacy and safety of the combination of cilostazol and EGb 761 in reducing early stroke recurrence and ND in patients with non-cardioembolic AIS.

METHODS

The RENEW trial is a prospective, randomized, active-controlled, double-blind, parallel, multicenter phase IV study. Five hundred patients with non-cardioembolic AIS presenting within 72 h of symptom onset will be randomized to receive either aspirin 100 mg and cilostazol 200 mg plus EGb 761 160 mg daily or aspirin 100 mg and clopidogrel 75 mg daily for 90 days. The primary outcomes included the combined ND rate during hospitalization and stroke recurrence within 90 days. Secondary outcomes included the rates of ND, recurrent AIS, hemorrhagic stroke, hemorrhagic transformation, functional outcomes (modified Rankin Scale 0-2), bleeding events, and changes in the dizziness handicap inventory scores.

DISCUSSION

The RENEW trial is expected to provide evidence for the safety and efficacy of combining aspirin, cilostazol, and EGb 761 as an alternative to standard therapy for the acute management of non-cardioembolic AIS.

TRIAL REGISTRATION

This trial was registered at ClinicalTrials.gov (NCT05445895).

Prediction Value of High Serum Pentraxin-3 for Short-Term Recurrence of Cerebral Infarction in Patients Accompanied with Intracranial Atherosclerotic Stenosis Within One Year

Objective

Elevated serum pentraxin-3 levels are generally considered a risk factor for atherosclerosis. However, there is limited data on the relationship between pentraxin-3 and cerebral infarction (CI) accompanied by intracranial atherosclerotic stenosis (ICAS). This study aims to investigate the association between pentraxin-3 (PTX-3) and short-term recurrence in cerebral infarction caused by ICAS patients within one year.

Methods

A prospective observational study was conducted. Cerebral infarction accompanied by intracranial atherosclerotic stenosis (CI-ICAS) patients were selected from January 2020 to December 2023. Recurrent ischemic stroke (RIS) is defined as a new neurological deficit that appears after a period of clinical stabilization, lasting more than 24 hours, with an attributable new ischemic lesion that can be confirmed by CT or MRI. Serum pentraxin-3 levels were determined on admission. Multivariate logistic regression analysis was used to investigate the relationship between serum pentraxin-3 and RIS.

Results

Among 398 patients enrolled, 112 cases (28.1%) had recurrence within one year. The elevation of serum PTX-3 level in patients accompanied with ICAS was independently correlated with recurrent stroke. Therefore, it is worth considering the possibility of intervening in higher PTX-3 levels. Serum pentraxin-3 was significantly higher in patients with RIS (15.16 vs 10.21 µmol/L, P<0.001). Correlation analysis showed that PTX-3 was correlated with age, LDL, Hs-CRP, Baseline NIHSS score, and Hcy (P < 0.001). Univariate logistic regression analysis showed that pentraxin-3 remained an independent predictor of recurrent ischemic stroke after adjusting for major confounding factors (OR = 1.21, 95% CI: 1.06-1.39, P = 0.007).

Conclusion

The elevation of serum pentraxin-3 level in patients with ischemic stroke was independently correlated with the recurrence of stroke within one year. Therefore, intervention in serum pentraxin-3 levels may be worth considering.

Efficacy of Colchicine for Secondary Prevention of Stroke: A Systematic Review and Meta-Analysis of Randomized Control Trials

Colchicine, a long-established anti-inflammatory medication, has emerged as a potential therapeutic agent for secondary prevention of stroke. This systematic review and meta-analysis aimed to evaluate the efficacy and safety of colchicine in preventing secondary stroke by comprehensively synthesizing available evidence. A systematic literature search was conducted across multiple electronic databases from inception to November 15, 2024, using comprehensive search strategies. Randomized controlled trials involving colchicine administration for stroke prevention were included. Two independent reviewers screened studies, extracted data, and assessed methodological quality using the Cochrane Risk of Bias tool. Meta-analysis was performed using Review Manager software, with risk ratios calculated for stroke incidence and all-cause mortality. The analysis encompassed seven studies involving 23,303 participants. The meta-analysis revealed a borderline significant 24% relative risk reduction in stroke incidence (risk ratio 0.76, 95% confidence interval 0.57-1.00, p = 0.05). Moderate heterogeneity was observed among studies (I² = 50%). Importantly, no significant difference was found in all-cause mortality between colchicine and control groups (risk ratio 1.03, 95% confidence interval 0.91-1.17, p = 0.66). While the findings suggest potential benefits of colchicine in stroke prevention, the results warrant cautious interpretation. The study emphasizes the need for larger, well-designed randomized controlled trials to definitively establish colchicine's role in comprehensive stroke prevention strategies.

Interleukin-6, C-Reactive Protein, and Recurrence After Stroke: A Time-Course Analysis of Individual-Participant Data

BACKGROUND

Inflammation promotes atherogenesis. Randomized controlled trials of anti-inflammatory therapies for prevention after stroke have not yet demonstrated clear benefit. IL-6 (interleukin-6) and hsCRP (high-sensitivity C-reactive protein) are independently associated with major adverse cardiovascular events poststroke and may guide patient selection in future randomized controlled trials. Optimal timing of hsCRP/IL-6 measurement poststroke is unknown, as early blood levels may be confounded by the inflammatory response to brain infarction.

METHODS

Using individual-participant data from a systematic review, we performed a time-course analysis to investigate the association between hsCRP/IL-6 and recurrent events stratified by timing of sampling. The prespecified coprimary end points after sample measurement were: (1) recurrent major adverse cardiovascular events (first major coronary event, recurrent stroke, or vascular death) and (2) recurrent stroke (ischemic, hemorrhagic, or unspecified). The poststroke dynamics of IL-6/hsCRP were analyzed by plotting their median (interquartile interval) concentrations within each tenth of the sampling timeframe. Acute/postacute phases were defined for each biomarker according to the shape of this relationship.

RESULTS

There were data for 9798 patients from 11 studies (19 891 person-years follow-up, 10 observational cohorts, and 1 randomized trial). Each marker was measured once. IL-6 was markedly elevated <24 hours poststroke compared with postacute levels (≥24 hours; 11.6 versus 3.02 pg/mL; P<0.001). HsCRP was elevated for 10 days. IL-6 was associated with recurrent major adverse cardiovascular events in the postacute phase (≥24 hours; risk ratio, 1.30 [CI, 1.19-1.41], per unit logeIL-6), but not in the acute phase (<24 hours; risk ratio, 1.10 [CI, 0.98-1.25]; Pinteraction=0.03). After adjustment for risk factors/medication, the association remained for postacute IL-6 when analyzed per logeunit (risk ratio, 1.16 [CI, 1.05-1.66]) and per quarter increase (risk ratio, 1.55 [CI, 1.19-2.02]; Q4 versus Q1), but not if measured acutely. Similar findings were observed for recurrent stroke. There was no evidence of time-dependent interaction with hsCRP.

CONCLUSIONS

Timing of sample measurement after stroke modifies the association with recurrent major adverse cardiovascular events for IL-6 but not hsCRP. These data inform future randomized controlled trial designs incorporating biomarker-based selection of patients for anti-inflammatory therapies.

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.

Pharmacological inhibition of mTORC1 reduces neural death and damage volume after MCAO by modulating microglial reactivity

Ischemic stroke is a sudden and acute disease characterized by neuronal death, increment of reactive gliosis (reactive microglia and astrocytes), and a severe inflammatory process. Neuroinflammation is an early event after cerebral ischemia, with microglia playing a leading role. Reactive microglia involve functional and morphological changes that drive a wide variety of phenotypes. In this context, deciphering the molecular mechanisms underlying such reactive microglial is essential to devise strategies to protect neurons and maintain certain brain functions affected by early neuroinflammation after ischemia. Here, we studied the role of mammalian target of rapamycin (mTOR) activity in the microglial response using a murine model of cerebral ischemia in the acute phase. We also determined the therapeutic relevance of the pharmacological administration of rapamycin, a mTOR inhibitor, before and after ischemic injury. Our data show that rapamycin, administered before or after brain ischemia induction, reduced the volume of brain damage and neuronal loss by attenuating the microglial response. Therefore, our findings indicate that the pharmacological inhibition of mTORC1 in the acute phase of ischemia may provide an alternative strategy to reduce neuronal damage through attenuation of the associated neuroinflammation.

Association between Interleukin-6 and Multiple Acute Infarctions in Symptomatic Intracranial Atherosclerotic Disease

BACKGROUND

Interleukin-6 (IL-6) plays an important role in the pathophysiology of atherosclerosis. This study aimed to determine whether IL-6 is a crucial biomarker associated with Multiple Acute Infarctions (MAIs), which indicate an important stroke mechanism of artery-to-artery embolism with a high risk of stroke recurrence in symptomatic Intracranial Atherosclerotic Disease (sICAD). We tested the association between circulating IL-6 levels and the presence of MAIs in a prospective population-based registry.

METHODS

We included 1,919 patients with sICAD and baseline IL-6 levels from the Third China National Stroke Registry for the current analysis, The baseline IL-6 was centrally measured at Beijing Tiantan Hospital, Images of the brain parenchyma and vascular structures were digitized and then blindly and independently read by two groups of trained readers, The recruited patients were divided into 3 groups according to IL-6 tertiles, The relationship between baseline IL-6 tertile levels and the presence of MAIs was modeled using multivariate logistic regression.

RESULTS

Compared to patients in the first IL-6 tertile those in the second and third tertiles demonstrated a significantly higher proportion of MAIs. The odds ratios were 1.81 [95% Confidence Interval (CI), 1.42-2.30] for the second versus first tertile and 2.15 (95% CI 1.66-2.79) for the third versus first tertile, The proportion of patients with MAIs increased with rising IL-6 tertiles observed at 59.3%, 71.6% and 76.4% for the first, second and third tertiles, respectively (P for trend < 0.001). The association between higher IL-6 tertiles and increased proportion of MAIs was also present in subgroups defined by age < 65 years, age ≥ 65 years, male, and high-sensitivity C-reactive Protein (hs-CRP) ≥ 2 mg/L. Furthermore, a significant interaction was detected for the hs- CRP subgroup (P = 0.038). In sensitivity analyses, the positive correlation between IL-6 levels and the proportion of MAIs remained consistent.

CONCLUSION

In patients with sICAD, higher IL-6 levels were associated with an increased proportion of MAIs. IL-6 could be used as a biomarker and a potential therapeutic target for future atherosclerosis treatment and prevention in patients with sICAD.