Thromboinflammation in Stroke Brain Damage

Mechanism of inflammatory response and therapeutic effects of stem cells in ischemic stroke: current evidence and future perspectives

Ischemic stroke is a leading cause of death and disability worldwide, with an increasing trend and tendency for onset at a younger age. China, in particular, bears a high burden of stroke cases. In recent years, the inflammatory response after stroke has become a research hotspot: understanding the role of inflammatory response in tissue damage and repair following ischemic stroke is an important direction for its treatment. This review summarizes several major cells involved in the inflammatory response following ischemic stroke, including microglia, neutrophils, monocytes, lymphocytes, and astrocytes. Additionally, we have also highlighted the recent progress in various treatments for ischemic stroke, particularly in the field of stem cell therapy. Overall, understanding the complex interactions between inflammation and ischemic stroke can provide valuable insights for developing treatment strategies and improving patient outcomes. Stem cell therapy may potentially become an important component of ischemic stroke treatment.

Neutrophil extracellular traps mediate neuro-immunothrombosis

Neutrophil extracellular traps are primarily composed of DNA and histones and are released by neutrophils to promote inflammation and thrombosis when stimulated by various inflammatory reactions. Neutrophil extracellular trap formation occurs through lytic and non-lytic pathways that can be further classified by formation mechanisms. Histones, von Willebrand factor, fibrin, and many other factors participate in the interplay between inflammation and thrombosis. Neuro-immunothrombosis summarizes the intricate interplay between inflammation and thrombosis during neural development and the pathogenesis of neurological diseases, providing cutting-edge insights into post-neurotrauma thrombotic events. The blood-brain barrier defends the brain and spinal cord against external assaults, and neutrophil extracellular trap involvement in blood-brain barrier disruption and immunothrombosis contributes substantially to secondary injuries in neurological diseases. Further research is needed to understand how neutrophil extracellular traps promote blood-brain barrier disruption and immunothrombosis, but recent studies have demonstrated that neutrophil extracellular traps play a crucial role in immunothrombosis, and identified modulators of neuro-immunothrombosis. However, these neurological diseases occur in blood vessels, and the mechanisms are unclear by which neutrophil extracellular traps penetrate the blood-brain barrier to participate in immunothrombosis in traumatic brain injury. This review discusses the role of neutrophil extracellular traps in neuro-immunothrombosis and explores potential therapeutic interventions to modulate neutrophil extracellular traps that may reduce immunothrombosis and improve traumatic brain injury outcomes.

Mitochondrial mechanisms in Cerebral Ischemia-Reperfusion Injury: Unravelling the intricacies

Cerebral ischemic stroke is a major contributor to physical impairments and premature death worldwide. The available reperfusion therapies for stroke in the form of mechanical thrombectomy and intravenous thrombolysis increase the risk of cerebral ischemia-reperfusion (I-R) injury due to sudden restoration of blood supply to the ischemic region. The injury is manifested by hemorrhagic transformation, worsening of neurological impairments, cerebral edema, and progression to infarction in surviving patients. A complex network of multiple pathological processes has been known to be involved in the pathogenesis of I-R injury. Primarily, 3 major contributors namely oxidative stress, neuroinflammation, and mitochondrial failure have been well studied in I-R injury. A transcription factor, Nrf2 (Nuclear factor erythroid 2-related factor 2) plays a crucial defensive role in resisting the deleterious effects of I-R injury and potentiating the cellular protective mechanisms. In this review, we delve into the critical function of mitochondria and Nrf2 in the context of cerebral I-R injury. We summarized how oxidative stress, neuroinflammation, and mitochondrial anomaly contribute to the pathophysiology of I-R injury and further elaborated the role of Nrf2 as a pivotal guardian of cellular integrity. The review further highlighted Nrf2 as a putative therapeutic target for mitochondrial dysfunction in cerebral I-R injury management.

Futile recanalization is associated with increased risk of post-stroke epilepsy

BACKGROUND

Endovascular treatment (EVT) is the standard of care of ischaemic stroke due to occlusion of large vessels. Although EVT can significantly improve short- and long-term outcomes, functional dependence can persist despite the achievement of a successful recanalization. The evidence about the predictors of post-stroke epilepsy (PSE) in patients with stroke treated by EVT is limited. We aimed to evaluate the relationship between futile recanalization and the risk of PSE.

METHODS

We retrospectively identified consecutive adults with first-ever ischaemic stroke of anterior circulation who were treated with EVT. Futile recanalization was defined as poor 3-month functional status (modified Rankin scale score ≥ 3) despite complete or near-complete recanalization. Study outcome was the occurrence of PSE during the follow-up.

RESULTS

The study included 327 patients with anterior circulation ischaemic stroke treated with EVT. Futile recanalization occurred in 116 (35.5%) patients and 26 (8.0%) developed PSE during a median follow-up of 35 [interquartile range, 22.7-55.2] months. Futile recanalization was more common among patients who developed PSE compared to those who did not (76.9% versus 31.9%; p < 0.001). Futile recanalization [hazard ratio (HR) = 5.63, 95% confidence interval (CI): 1.88-16.84; p = 0.002], large artery atherosclerosis (HR = 3.48, 95% CI: 1.44-8.40; p = 0.006), cortical involvement (HR = 15.51, 95% CI: 2.06-116.98; p = 0.008), and acute symptomatic status epilepticus (HR = 14.40, 95% CI: 2.80-73.98; p = 0.001) increased the risk of PSE.

CONCLUSIONS

Futile recanalization after EVT is associated with increased risk of PSE in patients with ischaemic stroke due to occlusion of large vessel of the anterior circulation.

Comprehensive Management of Stroke: From Mechanisms to Therapeutic Approaches

Acute ischemic stroke (AIS) is a challenging disease, which needs urgent comprehensive management. Endovascular thrombectomy (EVT), alone or combined with iv thrombolysis, is currently the most effective therapy for patients with acute ischemic stroke (AIS). However, only a limited number of patients are eligible for this time-sensitive treatment. Even though there is still significant room for improvement in the management of this group of patients, up until now there have been no alternative therapies approved for use in clinical practice. However, there is still hope, as clinical research with novel emerging therapies is now generating promising results. These drugs happen to stop or palliate some of the underlying molecular mechanisms involved in cerebral ischemia and secondary brain damage. The aim of this review is to provide a deep understanding of these mechanisms and the pathogenesis of AIS. Later, we will discuss the potential therapies that have already demonstrated, in preclinical or clinical studies, to improve the outcomes of patients with AIS.

Microglia-neuron-vascular interactions in ischemia

Cerebral ischemia is a devastating condition that results in impaired blood flow in the brain leading to acute brain injury. As the most common form of stroke, occlusion of cerebral arteries leads to a characteristic sequence of pathophysiological changes in the brain tissue. The mechanisms involved, and comorbidities that determine outcome after an ischemic event appear to be highly heterogeneous. On their own, the processes leading to neuronal injury in the absence of sufficient blood supply to meet the metabolic demand of the cells are complex and manifest at different temporal and spatial scales. While the contribution of non-neuronal cells to stroke pathophysiology is increasingly recognized, recent data show that microglia, the main immune cells of the central nervous system parenchyma, play previously unrecognized roles in basic physiological processes beyond their inflammatory functions, which markedly change during ischemic conditions. In this review, we aim to discuss some of the known microglia-neuron-vascular interactions assumed to contribute to the acute and delayed pathologies after cerebral ischemia. Because the mechanisms of neuronal injury have been extensively discussed in several excellent previous reviews, here we focus on some recently explored pathways that may directly or indirectly shape neuronal injury through microglia-related actions. These discoveries suggest that modulating gliovascular processes in different forms of stroke and other neurological disorders might have presently unexplored therapeutic potential in combination with neuroprotective and flow restoration strategies.

Targeting brain-peripheral immune responses for secondary brain injury after ischemic and hemorrhagic stroke

The notion that the central nervous system is an immunologically immune-exempt organ has changed over the past two decades, with increasing evidence of strong links and interactions between the central nervous system and the peripheral immune system, both in the healthy state and after ischemic and hemorrhagic stroke. Although primary injury after stroke is certainly important, the limited therapeutic efficacy, poor neurological prognosis and high mortality have led researchers to realize that secondary injury and damage may also play important roles in influencing long-term neurological prognosis and mortality and that the neuroinflammatory process in secondary injury is one of the most important influences on disease progression. Here, we summarize the interactions of the central nervous system with the peripheral immune system after ischemic and hemorrhagic stroke, in particular, how the central nervous system activates and recruits peripheral immune components, and we review recent advances in corresponding therapeutic approaches and clinical studies, emphasizing the importance of the role of the peripheral immune system in ischemic and hemorrhagic stroke.

An Explainable Artificial Intelligence Model to Predict Malignant Cerebral Edema after Acute Anterior Circulating Large-Hemisphere Infarction

INTRODUCTION

Malignant cerebral edema (MCE) is a serious complication and the main cause of poor prognosis in patients with large-hemisphere infarction (LHI). Therefore, the rapid and accurate identification of potential patients with MCE is essential for timely therapy. This study utilized an artificial intelligence-based machine learning approach to establish an interpretable model for predicting MCE in patients with LHI.

METHODS

This study included 314 patients with LHI not undergoing recanalization therapy. The patients were divided into MCE and non-MCE groups, and the eXtreme Gradient Boosting (XGBoost) model was developed. A confusion matrix was used to measure the prediction performance of the XGBoost model. We also utilized the SHapley Additive exPlanations (SHAP) method to explain the XGBoost model. Decision curve and receiver operating characteristic curve analyses were performed to evaluate the net benefits of the model.

RESULTS

MCE was observed in 121 (38.5%) of the 314 patients with LHI. The model showed excellent predictive performance, with an area under the curve of 0.916. The SHAP method revealed the top 10 predictive variables of the MCE such as ASPECTS score, NIHSS score, CS score, APACHE II score, HbA1c, AF, NLR, PLT, GCS, and age based on their importance ranking.

CONCLUSION

An interpretable predictive model can increase transparency and help doctors accurately predict the occurrence of MCE in LHI patients not undergoing recanalization therapy within 48 h of onset, providing patients with better treatment strategies and enabling optimal resource allocation.

Intensive Versus Standard Blood Pressure Management after Endovascular Therapy for Acute Ischemic Stroke: A Systematic Review and Meta-analysis

Prospective clinical studies on blood pressure (BP) management targets after endovascular therapy (EVT) for acute ischemic stroke (AIS) have recently been published. Our objective was to assess the impact on clinical outcomes of BP management guided by established systolic BP (SBP) targets within the first 24 hours after successful EVT. Four randomized controlled trials (RCTs) including 1556 participants across 5 SBP target settings identified from 5 databases up to September 6, 2023 were included in this systematic review and meta-analysis. All the intensive SBP target groups in these RCTs were combined to facilitate head-to-head comparisons. Patients receiving intensive SBP management had lower risk of 90-day functional independence as assessed by the modified Rankin scale score (relative risk [RR], 0.81; 95% confidence interval [CI], 0.72 to 0.91; I2, 12%), excellent outcomes (RR,0.86; 95% CI, 0.75 to 0.99; I2, 7%), favorable outcomes (RR, 0.85; 95% CI, 0.78 to 0.92; I2, 0%), and quality of life (standardized mean difference, -0.22; 95% CI, -0.35 to -0.10; I2,0%). There were no differences in the probability of any intracerebral hemorrhage (RR, 1.04; 95% CI, 0.92 to 1.19; I2,0%), symptomatic intracerebral hemorrhage (RR, 1.10; 95% CI, 0.76 to 1.60; I2, 0%), stroke-related death (RR, 1.16; 95% CI, 0.80 to 1.68; I2, 0%), or parenchymal hematoma (RR, 1.71; 95% CI, 0.74 to 3.98; I2, 47%) between SBP targets. This meta-analysis provides evidence from RCTs suggesting that intensive SBP control (target<160 mm Hg) may be detrimental to clinical outcomes in AIS patients with successful reperfusion after EVT.

Pretreatment with a dual antiplatelet and anticoagulant (APAC) reduces ischemia-reperfusion injury in a mouse model of temporary middle cerebral artery occlusion-implications for neurovascular procedures

BACKGROUND

Several neurovascular procedures require temporary occlusion of cerebral arteries, leading to ischemia of unpredictable length, occasionally causing brain infarction. Experimental models of cerebral ischemia-reperfusion injury have established that platelet adhesion and coagulation play detrimental roles in reperfusion injury following transient cerebral ischemia. Therefore, in a model of cerebral ischemia-reperfusion injury (IRI), we investigated the therapeutic potential of a dual antiplatelet and anticoagulant (APAC) heparin proteoglycan mimetic which is able to bind to vascular injury sites.

METHODS

Brain ischemia was induced in mice by transient occlusion of the right middle cerebral artery for 60 min. APAC, unfractionated heparin (UFH) (both at heparin equivalent doses of 0.5 mg/kg), or vehicle was intravenously administered 10 min before or 60 min after the start of ischemia. At 24 h later, mice were scored for their neurological and motor behavior, and brain damage was quantified.

RESULTS

Both APAC and UFH administered before the onset of ischemia reduced brain injury. APAC and UFH pretreated mice had better neurological and motor functions (p < 0.05 and p < 0.01, respectively) and had significantly reduced cerebral infarct sizes (p < 0.01 and p < 0.001, respectively) at 24 h after transient occlusion compared with vehicle-treated mice. Importantly, no macroscopic bleeding complications were observed in either APAC- or UFH-treated animals. However, when APAC or UFH was administered 60 min after the start of ischemia, the therapeutic effect was lost, but without hemorrhaging either.

CONCLUSIONS

Pretreatment with APAC or UFH was safe and effective in reducing brain injury in a model of cerebral ischemia induced by transient middle cerebral artery occlusion. Further studies on the use of APAC to limit ischemic injury during temporary occlusion in neurovascular procedures are indicated.

High Systemic Inflammatory Protein Index Is Associated with Clinically Ineffective Reperfusion in Acute Anterior Circulation Ischemic Stroke Patients Undergoing Endovascular Treatment

Nearly half of the patients undergoing endovascular treatment (EVT) do not have favorable outcomes despite successful recanalization of the occluded artery, which is also known as clinically ineffective reperfusion. We proposed a novel index-the systemic inflammatory protein index (SIPI), based on albumin, globulin, and C-reaction protein (CRP). We aimed to evaluate the relationship between inflammatory biomarkers at varying time points and the 90-day functional outcomes and investigate inflammatory biomarkers' dynamic changes during hospitalization in acute ischemic stroke (AIS) patients of anterior circulation undergoing EVT. We retrospectively recruited consecutive patients diagnosed with AIS of anterior circulation and treated with EVT from January 2018 to June 2022 in Nanfang Hospital. Albumin, globulin, and CRP were recorded on admission, 1 day, 3 days, and 7 days after EVT. An unfavorable functional outcome was defined as 90-day modified Rankin Scale (mRS) of 3-6. Albumin-to-globulin ratio (AGR), C-reactive protein-to-albumin ratio (CAR), and SIPI were calculated as follows: AGR = albumin/globulin; CAR = CRP/albumin; SIPI = CRP × globulin/albumin. A total of 238 consecutive anterior circulation AIS patients with EVT were included, among which 145 (60.9%) patients had unfavorable outcomes. After adjusting for confounding factors, admission globulin, admission AGR, 1-day AGR, 3-day albumin, 3-day CRP, 3-day CAR, 3-day SIPI, 7-day albumin, 7-day CRP, 7-day CAR, and 7-day SIPI showed an independent association with 90-day functional outcome. Of them, 3-day SIPI had the most robust discriminative ability with an area under the curve of 0.719 (CI 0.630-0.808, p < 0.001). There were differences in the dynamic change of inflammatory biomarkers between the subjects with favorable and unfavorable functional outcomes. Inflammatory biomarkers, including albumin, globulin, CRP, AGR, CAR, and SIPI, are independent predictors of 90-day unfavorable outcomes in anterior circulation AIS patients with EVT. SIPI of day 3 has the highest predictive value.

Association Between Hematoma Volume and Risk of Subsequent Ischemic Stroke: A MISTIE III and ATACH-2 Analysis

BACKGROUND

Nontraumatic intracerebral hemorrhage (ICH) is independently associated with a long-term increased risk of major arterial ischemic events. While the relationship between ICH location and ischemic risk has been studied, whether hematoma volume influences this risk is poorly understood.

METHODS

We pooled individual patient data from the MISTIE III (Minimally Invasive Surgery Plus Alteplase for Intracerebral Hemorrhage Evacuation Phase 3) and the ATACH-2 (Antihypertensive Treatment of Acute Cerebral Hemorrhage-2) trials. The exposure was hematoma volume, treated as a continuous measure in the primary analysis, and dichotomized by the median in the secondary analyses. The outcome was a symptomatic, clinically overt ischemic stroke, adjudicated centrally within each trial. We evaluated the association between hematoma volume and the risk of an ischemic stroke using Cox regression analyses after adjustment for demographics, vascular comorbidities, and ICH characteristics.

RESULTS

Of 1470 patients with ICH, the mean age was 61.7 (SD, 12.8) years, and 574 (38.3%) were female. The median hematoma volume was 17.3 mL (interquartile range, 7.2-35.7). During a median follow-up of 107 days (interquartile range, 91-140), a total of 30 ischemic strokes occurred, of which 22 were in patients with a median ICH volume of ≥17.3 mL and a cumulative incidence of 4.6% (95% CI, 3.1-7.1). Among patients with a median ICH volume <17.3 mL, there were 8 ischemic strokes with a cumulative incidence of 3.1% (95% CI, 1.7-6.0). In primary analyses using adjusted Cox regression models, ICH volume was associated with an increased risk of ischemic stroke (hazard ratio, 1.02 per mL increase [95% CI, 1.01-1.04]). In secondary analyses, ICH volume of ≥17.3 mL was associated with an increased risk of ischemic stroke (hazard ratio, 2.5 [95% CI, 1.1-7.2]), compared with those with an ICH volume <17.3 mL.

CONCLUSIONS

In a heterogeneous cohort of patients with ICH, initial hematoma volume was associated with a heightened short-term risk of ischemic stroke.

Development and validation of a prediction model for postoperative ischemic stroke following total arch replacement and frozen elephant trunk under mild hypothermia

Background

Early identification of postoperative ischemic stroke among patients with acute DeBakey type I aortic dissection (ADIAD) is of great significance to taking timely effective treatment. We aimed to develop and validate a prediction model for postoperative ischemic stroke in ADIAD patients who underwent total arch replacement (TAR) and frozen elephant trunk (FET) under mild hypothermia.

Methods

ADIAD patients who underwent TAR and FET between January 2017 and April 2023 were enrolled in our study. Preoperative and intraoperative variables were selected using pairwise comparisons, the Least Absolute Shrinkage and Selection Operator (LASSO), and logistic regression to construct a prediction model for postoperative ischemic stroke. The accuracy and calibration of the model were assessed using 1000 bootstrap resamples for internal validation, with the area under the receiver operating characteristic curve (AUC) and the Hosmer-Lemeshow test. The AUC was also used to evaluate the model's accuracy in the validation cohort.

Results

The development cohort included 246 patients. The mean [standard deviation (SD)] age of patients in the cohort was 50.7 (11.2) years, 196 (79.7%) were men, and 22 (8.9%) were diagnosed with postoperative ischemic stroke. The validation cohort included 73 patients with a mean (SD) age of 52.5 (11.9) years, 58 (79.5%) were men and 3 (4.1%) were diagnosed with postoperative ischemic stroke. Three variables out of the initial 40 potential predictors were included in the final prediction model: the platelet count [odd ratio (OR), 0.992; 95% confidence interval (CI), 0.983-1.000], the presence of innominate artery dissection (OR, 3.400; 95% CI, 1.027-11.260), and the flow of selective cerebral perfusion (OR, 0.147; 95% CI, 0.046-0.469). The mean AUC in the development cohort was 0.77 (95% CI, 0.68-0.87), and calibration was checked with the Hosmer-Lemeshow test (P = 0.78). In the validation cohort, the AUC was 0.98 (95% CI, 0.94-1.00). A prediction model and a clinical impact curve were developed for practical purposes.

Conclusions

In this study, we have developed a prediction model with competent discriminative ability and calibration. This model can be used for early assessment of the risk of postoperative ischemic stroke in patients with ADIAD following TAR and FET under mild hypothermia.

AIM2 inflammasome: A potential therapeutic target in ischemic stroke

Ischemic stroke (IS) is a significant global public health issue with a high incidence, disability, and mortality rate. A robust inflammatory cascade with complex and wide-ranging mechanisms occurs following ischemic brain injury. Inflammasomes are multiprotein complexes in the cytoplasm that modulate the inflammatory response by releasing pro-inflammatory cytokines and inducing cellular pyroptosis. Among these inflammasomes, the Absent in Melanoma 2 (AIM2) inflammasome shows the ability to detect a wide range of pathogen DNAs, thereby triggering an inflammatory response. Recent studies have indicated that the aberrant expression of AIM2 inflammasome in various cells is closely associated with the pathological processes of ischemic brain injury. This paper summarizes the expression and regulatory role of AIM2 in CNS and peripheral immune cells and discusses current therapeutic approaches targeting AIM2 inflammasome. These findings aim to serve as a reference for future research in this field.

White blood cell subtypes and neutrophil extracellular traps content as biomarkers for stroke etiology in acute ischemic stroke clots retrieved by mechanical thrombectomy

BACKGROUND

Lymphocytes, macrophages, neutrophils, and neutrophil extracellular traps (NETs) associate with stroke risk factors and form a thrombus through different mechanisms. We investigated the total WBCs, WBC subtypes and NETs composition in acute ischemic stroke (AIS) clots to identify possible etiological differences that could help us further understand the process of thrombosis that leads to AIS.

METHODS

AIS clots from 100 cases each of atherothrombotic (AT), cardioembolic (CE) and cryptogenic stroke etiology were collected per-pass as part of the CÚRAM RESTORE registry of AIS clots. Martius Scarlet Blue stain was used to identify the main histological components of the clots. Immunohistochemical staining was used to identify neutrophils, lymphocytes, macrophages, and NETs patterns. The cellular and histological components were quantified using Orbit Image Analysis software.

RESULTS

AT clots were larger, with more red blood cells and fewer WBCs than CE clots. AT clots had more lymphocytes and cryptogenic clots had fewer macrophages than other etiologies. Most significantly, CE clots showed higher expression of neutrophils and extracellular web-like NETs compared to AT and cryptogenic clots. There was also a significantly higher distribution of web-like NETs around the periphery of the CE clots while a mixed distribution was observed in AT clots.

CONCLUSION

The difference in neutrophil and NETs expression in clots from different etiologies may provide insight into the mechanism of clot formation.

A lone spike in blood glucose can enhance the thrombo-inflammatory response in cortical venules

How transient hyperglycemia contributes to cerebro-vascular disease has been a challenge to study under controlled physiological conditions. We use amplified, ultrashort laser-pulses to physically disrupt brain-venule endothelium at targeted locations. This vessel disruption is performed in conjunction with transient hyperglycemia from a single injection of metabolically active D-glucose into healthy mice. The observed real-time responses to laser-induced disruption include rapid serum extravasation, platelet aggregation, and neutrophil recruitment. Thrombo-inflammation is pharmacologically ameliorated by a platelet inhibitor, by a scavenger of reactive oxygen species, and by a nitric oxide donor. As a control, vessel thrombo-inflammation is significantly reduced in mice injected with metabolically inert L-glucose. Venules in mice with diabetes show a similar response to laser-induced disruption and damage is reduced by restoration of normo-glycemia. Our approach provides a controlled method to probe synergies between transient metabolic and physical vascular perturbations and can reveal new aspects of brain pathophysiology.

Hypoxia and interleukin-1-primed mesenchymal stem/stromal cells as novel therapy for stroke

Promising preclinical stroke research has not yielded meaningful and significant success in clinical trials. This lack of success has prompted the need for refinement of preclinical studies with the intent to optimize the chances of clinical success. Regenerative medicine, especially using mesenchymal stem/stromal cells (MSCs), has gained popularity in the last decade for treating many disorders, including central nervous system (CNS), such as stroke. In addition to less stringent ethical constraints, the ample availability of MSCs also makes them an attractive alternative to totipotent and other pluripotent stem cells. The ability of MSCs to differentiate into neurons and other brain parenchymal and immune cells makes them a promising therapy for stroke. However, these cells also have some drawbacks that, if not addressed, will render MSCs unfit for treating ischaemic stroke. In this review, we highlighted the molecular and cellular changes that occur following an ischaemic stroke (IS) incidence and discussed the physiological properties of MSCs suitable for tackling these changes. We also went further to discuss the major drawbacks of utilizing MSCs in IS and how adequate priming using both hypoxia and interleukin-1 can optimize the beneficial properties of MSCs while eliminating these drawbacks.

Sex Differences in Thrombin Generation in Patients with Acute Ischemic Stroke

Sex differences in stroke exist, including variation in stroke risk and outcome. Differences in thrombin generation may contribute to this variation between females and males. To examine this, we assessed sex differences in thrombin generation between females and males with acute ischemic stroke and the relationship to blood cell gene expression. In 97 patients with acute ischemic stroke, thrombin generation was measured by thrombin generation assay. Blood cell gene expression was measured by microarray. Differences in thrombin generation between sexes were identified and the relationship to blood cell gene expression examined. Genes associated with sex differences in thrombin generation were analyzed by functional pathway analysis. Females and males had similar overall capacity to generate thrombin. The peak thrombin generated in females was 468.8 nM (SD 91.6), comparable to males (479.3nM;SD 90.8; p = 0.58). Lag time, time to peak thrombin, and endogenous thrombin potential were also similar between females and males. While overall thrombin generation was comparable between females and males with stroke, differences in genes that promote this thrombin generation exist. Females with high peak thrombin had an increase in genes that promote thrombosis, and platelet activation. In contrast, males with high peak thrombin had a decrease in genes involved in thrombus degradation. Females and males with acute ischemic stroke have similar capacity to generate thrombin, however, differences may exist in how this thrombin generation is achieved, with females having increased thrombin signaling, and platelet activation, and males having decreased thrombus degradation. This suggests regulatory differences in thrombosis may exist between females and males that may contribute to sex differences in stroke.

Neuroprotection Is in the Air-Inhaled Gases on Their Way to the Neurons

Cerebral injury is a leading cause of long-term disability and mortality. Common causes include major cardiovascular events, such as cardiac arrest, ischemic stroke, and subarachnoid hemorrhage, traumatic brain injury, and neurodegenerative as well as neuroinflammatory disorders. Despite improvements in pharmacological and interventional treatment options, due to the brain's limited regeneration potential, survival is often associated with the impairment of crucial functions that lead to occupational inability and enormous economic burden. For decades, researchers have therefore been investigating adjuvant therapeutic options to alleviate neuronal cell death. Although promising in preclinical studies, a huge variety of drugs thought to provide neuroprotective effects failed in clinical trials. However, utilizing medical gases, noble gases, and gaseous molecules as supportive treatment options may offer new perspectives for patients suffering neuronal damage. This review provides an overview of current research, potentials and mechanisms of these substances as a promising therapeutic alternative for the treatment of cerebral injury.

Plasma von Willebrand Factor Is Elevated Hyperacutely After Mild Traumatic Brain Injury

Each year in the United States, ∼2.7 million persons seek medical attention for traumatic brain injury (TBI), of which ∼85% are characterized as being mild brain injuries. Many different cell types in the brain are affected in these heterogeneous injuries, including neurons, glia, and the brain vasculature. Efforts to identify biomarkers that reflect the injury of these different cell types have been a focus of ongoing investigation. We hypothesized that von Willebrand factor (vWF) is a sensitive biomarker for acute traumatic vascular injury and correlates with symptom severity post-TBI. To address this, blood was collected from professional boxing athletes (n = 17) before and within 30 min after competition. Plasma levels of vWF and neuron-specific enolase were measured using the Meso Scale Discovery, LLC. (MSD) electrochemiluminescence array-based multi-plex format (MSD, Gaithersburg, MD). Additional symptom and outcome data from boxers and patients, such as the Rivermead symptom scores (Rivermead Post Concussion Symptoms Questionnaire [RPQ-3]), were collected. We found that, subsequent to boxing bouts, there was a 1.8-fold increase in vWF levels within 30 min of injury (p < 0.0009). Moreover, fold-change in vWF correlates moderately (r = 0.51; p = 0.03) with the number of head blows. We also found a positive correlation (r = 0.69; p = 0.002) between fold-change in vWF and self-reported post-concussive symptoms, measured by the RPQ-3. The receiver operating curve analysis of vWF plasma levels and RPQ-3 scoring yielded a sensitivity of 94.12% and a specificity of 76.5% with an area under the curve of 83% for boxers after a fight compared to the pre-bout baseline. This study suggests that vWF is a potential blood biomarker measurable in the hyperacute period after blunt mild TBI. This biomarker may prove to be useful in diagnosing and monitoring traumatic vascular injury.

Effect of routine inflammatory markers on clinical outcomes in acute basilar artery occlusion after endovascular thrombectomy: Results from ATTENTION registry

BACKGROUND

To investigate the relationship between clinical routine inflammatory markers, including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), mean platelet volume (MPV), white blood cell count (WBC), neutrophils, lymphocytes, and platelets with clinical outcomes in acute basilar artery occlusion (BAO) patients receiving endovascular treatment (EVT).

METHODS

We recruited 2134 acute BAO patients from 48 stroke centers across 22 Chinese provinces in the ATTENTION registry from 2017 to 2021. Blood samples were drawn at admission. An unfavorable functional outcome was defined using a modified Rankin Scale (mRS) of 4-6 at 90 days. Safety outcomes included mortality within 90 days and symptomatic intracerebral hemorrhage within 3 days.

RESULTS

A total of 1044 patients were included in the final study. After adjusting for confounding factors, the upper quartiles of WBC and NLR were related to 90-day unfavorable functional outcome (mRS = 4-6) compared with those in the lowest quartile (WBC: quartile 4, odds ratio (OR) = 1.85, 95% confidence interval (CI) = 1.22-2.80; NLR: quartile 4, OR = 2.02, 95% CI = 1.34-3.06). The higher quartiles of WBC and NLR were also related to the increased risk of mortality at 90 days. Restricted cubic spline regression analysis showed an incremental trend between NLR and 90-day unfavorable functional outcome (Pnonlinearity = 0.055). In subgroup analysis, a significant interaction was found between NLR and bridging therapy for predicting unfavorable functional outcome (P = 0.006).

CONCLUSION

Higher WBC and NLR on admission are significantly related to unfavorable functional outcome and mortality at 90 days in acute BAO patients receiving EVT. Significant interaction was found between increased NLR and bridging therapy on these outcome measures.

Neuroprotective effects of Coenzyme Q10 in ischemia-reperfusion injury via inflammation and oxidative stress reduction in adult male rats

This study aimed to investigate the potential neuroprotective effects of coenzyme Q10 in cerebral ischemia-reperfusion injury-induced neuronal damage and explore the underlying mechanisms. Twenty-eight adult male rats, weighing approximately 200-300 grams, were randomly divided into four groups: the sham group (neck dissection without ischemia), the control group (30 minutes of bilateral common carotid artery ligation followed by one hour of reperfusion), the vehicle group (oral carboxymethylcellulose solution for seven days prior to bilateral common carotid artery ligation and reperfusion), and the treatment group (seven days of coenzyme Q10 pretreatment followed by bilateral common carotid artery occlusion and reperfusion). Histopathological analysis and measurement of brain infarct size were performed, and cerebral levels of IL-6, IL-10, TNF-α, ICAM-1, NF-κB p65, and total antioxidant capacity were assessed. These cerebral tissue levels and cerebral infarct size were significantly elevated in the control and vehicle groups compared to the sham group. Conversely, the total antioxidant capacity was significantly reduced in these groups. Coenzyme Q10 treatment resulted in a significant increase in IL-10 and total antioxidant capacity levels, along with a significant decrease in IL-6, ICAM-1, TNF-α, and NF-κB p65 levels. Histopathological analysis revealed a significant reduction in ischemic damage in the coenzyme Q10-treated group. Coenzyme Q10 has neuroprotective properties in rats subjected to cerebral ischemia/reperfusion injury, possibly through its anti-inflammatory and anti-oxidative effects.

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

BACKGROUND AND PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Association of Admission Glucose and Outcomes After Endovascular Treatment for Acute Stroke: Data From the ANGEL-ACT Registry

BACKGROUND

The association between admission glucose levels and clinical outcomes after stroke has not been effectively elucidated. This study assessed the association among admission glucose levels, admission hyperglycemia, diabetes mellitus, and 90-day neurological outcomes in patients with acute ischemic stroke undergoing endovascular therapy.

METHODS

The ANGEL-ACT registry enrolled adults with acute ischemic stroke undergoing endovascular therapy between 2017 and 2019 in China and patients with available admission glucose data were included. Restricted cubic spline regression was used to determine the knots of blood glucose levels. Binary or ordinal logistic regression models were used to examine the impact of different admission glucose levels on neurological outcomes and 90-day mortality.

RESULTS

In total, 1684 participants with available admission glucose concentrations were evaluated. The admission glucose level was divided into 4 levels according to the restricted cubic spline curves: level 1 (<5.3 mmol/L), level 2 (5.3 to 7.0 mmol/L), level 3 (7.0 to 11.6 mmol/L), and level 4 (≥11.6 mmol/L). Level 4 admission glucose was associated with a decreased incidence of a modified Rankin scale score of 0 to 2 (hazard ratio, 0.59; 95% CI, 0.40-0.87) and an increased risk of mortality (hazard ratio, 1.74; 95% CI, 1.06-2.85). Levels 3 and 4, hyperglycemia, and diabetes mellitus independently predicted symptomatic intracranial hemorrhage (sICH). Admission glucose levels showed J-shaped relationships with sICH.

CONCLUSIONS

Higher admission glucose levels (≥11.6 mmol/L) were associated with a decreased likelihood of a modified Rankin scale score of 0 to 2 and an increased risk of mortality and sICH.

Admission NLPR predicts long-term mortality in patients with acute ischemic stroke: A retrospective analysis of the MIMIC-III database

BACKGROUND

The neutrophil to lymphocyte*platelet ratio (NLPR) is a new index based on platelets, neutrophils, and lymphocytes associated with the prognosis of patients with infectious diseases and cancer. However, its use in acute ischemic stroke has rarely been reported. This study examined the relationship between levels of systemic immunoinflammatory indices at admission and patient outcomes at different times after onset to assess stroke prognosis by NLPR.

METHODS

This was a retrospective cohort study. The data from 1222 stroke patients were obtained from multi-parameter intelligent monitoring in the Intensive Care III database(MIMIC- III). Cox proportional risk model was conducted to evaluate the relation between NLPR, all-cause mortality, and ischemic. The results were further verified via a subgroup analysis.

RESULTS

After adjusting for multiple covariates, it was found that NLPR was related with all-cause mortality in stroke patients. High NLPR was accompanied by an increase in mortality with longer follow-up (30 days: HR = 1.52, 95% CI = 1.14-2.02,90 days: HR = 1.67, 95% CI = 1.29-2.16, 365 days: HR = 1.56, 95% CI = 1.24-1.96 and 2 years: HR = 1.52, 95% CI = 1.22-1.89).

CONCLUSION

The neutrophil to lymphocyte*platelet ratio (NLPR) are related to long-term adverse outcomes in patients with acute ischemic stroke. Therefore, NLPR is a promising inflammatory index for predicting the long-term prognosis of stroke.

Neuroinflammation and anti-inflammatory therapy for ischemic stroke

Stroke remains one of the most devastating and challenging neurological diseases worldwide. Inflammation, as well as oxidative stress is one of the main contributors to post-stroke injuries, and oxidative stress can further induce inflammation. Moreover, the inflammatory response is closely related to immune modulation in ischemic stroke progression. Hence, major ischemic stroke treatment strategies include targeting inflammatory responses, immune modulation (especially immune cells), and inflammatory response to suppress stroke progression. To date, several drugs have demonstrated clinical efficacy, such as Etanercept and Fingolimod. However, only edaravone dexborneol has successfully passed the phase III clinical trial and been approved by the National Medical Products Administration (NMPA) to treat ischemic stroke in China, which can restore redox balance and regulate inflammatory immune responses, thus providing neuroprotection in ischemic stroke. In this review, we will comprehensively summarize the current advances in the application of inflammatory biomarkers, neuroinflammation and neuro-immunotherapeutic scenarios for ischemic stroke, thus aiming to provide a theoretical basis and new prospects and frontiers for clinical applications.

Association between Citrullinated Histone H3 and White Matter Lesions Burden in Patients with Ischemic Stroke

INTRODUCTION

Neutrophil extracellular traps play a role in the pathophysiology of stroke and are associated with severity and mortality. We aimed to investigate whether the citrullinated histone H3 (CitH3), a biomarker for neutrophil extracellular traps formation, is associated with the white matter lesion (WML) burden in ischemic stroke patients.

METHODS

Between September 2021 and April 2022, 322 patients were enrolled in this prospective observational cohort study. Serum CitH3 levels were measured after admission using an enzyme-linked immunosorbent assay. WMLs severity was graded according to the Fazekas scale and conceptually defined as mild (total Fazekas score 0-2) and severe (total Fazekas score 3-6). We used multivariable regression models to determine the relationship between CitH3 concentrations and the severity of WMLs burden.

RESULTS

One-hundred and forty-eight (46.0%) patients were diagnosed with severe WMLs burden after admission. Increased CitH3 levels (first quartile vs. fourth quartile of H3Cit, odds ratio, 3.311, 95% confidence interval, 1.336-8.027; p = 0.011) were independently associated with a greater WML burden in the fully adjusted multivariable model. Similar results were found when the H3Cit was analyzed as a continuous variable. Furthermore, the multiple-adjusted spline regression model showed a linear association between H3Cit levels and severe WMLs (P = 0.001 for linearity).

CONCLUSIONS

In the present study, increased CitH3 levels were positively associated with extensive WMLs in ischemic stroke patients, indicating a role of neutrophil extracellular traps formation in the pathogenesis of WMLs.

An In Silico Analysis Reveals Sustained Upregulation of Neuroprotective Genes in the Post-Stroke Human Brain

Ischemic stroke is a cerebrovascular disease caused by an interruption of blood flow to the brain, thus determining a lack of oxygen and nutrient supply. The ischemic event leads to the activation of several molecular signaling pathways involved in inflammation and the production of reactive oxygen species, causing irreversible neuronal damage. Several studies have focused on the acute phase of ischemic stroke. It is not clear if this traumatic event can influence some of the molecular processes in the affected area even years after the clinical event. In our study, we performed an in silico analysis using freely available raw data with the purpose of evaluating the transcriptomic state of post-mortem brain tissue. The samples were taken from non-fatal ischemic stroke patients, meaning that they suffered an ischemic stroke and lived for a period of about 2 years after the event. These samples were compared with healthy controls. The aim was to evaluate possible recovery processes useful to mitigating neuronal damage and the detrimental consequences of stroke. Our results highlighted differentially expressed genes codifying for proteins along with long non-coding genes with anti-inflammatory and anti-oxidant functions. This suggests that even after an amount of time from the ischemic insult, different neuroprotective mechanisms are activated to ameliorate brain conditions and repair post-stroke neuronal injury.

Human umbilical cord blood mononuclear cells ameliorate ischemic brain injury via promoting microglia/macrophages M2 polarization in MCAO Rats

Cerebral infarction is one of the most prevalent cerebrovascular disorders. Microglia and infiltrating macrophages play a key role in regulating the inflammatory response after ischemic stroke. Regulation of microglia/macrophages polarization contributes to the recovery of neurological function in cerebral infarction. In recent decades, human umbilical cord blood mononuclear cells (hUCBMNCs) have been considered a potential therapeutic alternative. However, the mechanism of action is yet unclear. Our study aimed to explore whether hUCBMNCs treatment for cerebral infarction is via regulation of microglia/macrophages polarization. Adult male Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO) and were treated by intravenous routine with or without hUCBMNCs at 24 h following MCAO. We evaluated the therapeutic effects of hUCBMNCs on cerebral infarction by measuring animal behavior and infarct volume, and further explored the possible mechanisms of hUCBMNCs for cerebral infarction by measuring inflammatory factors and microglia/macrophages markers using Elisa and immunofluorescence staining, respectively. We found that administration with hUCBMNCs improved behavioral functions and reduced infarct volume. Rats treated with hUCBMNCs showed a significant reduction in the level of IL-6, and TNF-α and increased the level of IL-4 and IL-10 compared to those treated without hUCBMNCs. Furthermore, hUCBMNCs inhibited M1 polarization and promoted M2 polarization of microglia/macrophages after MCAO. We conclude that hUCBMNCs could ameliorate cerebral brain injury by promoting microglia/macrophages M2 polarization in MCAO Rats. This experiment provides evidence that hUCBMNCs represent a promising therapeutic option for ischemic stroke.

Else_BRB_110660Docosahexaenoic acid promotes M2 microglia phenotype via activating PPARγ-mediated ERK/AKT pathway against cerebral ischemia-reperfusion injury

In ischemia-reperfusion stroke, microglia play a dual role in brain injury as well as brain repair, and promoting their switch from a pro-inflammatory M1 phenotype to an anti-inflammatory M2 phenotype is considered to be a potential therapeutic strategy. Docosahexaenoic acid (DHA) is an essential long-chain omega-3 polyunsaturated fatty acid that exhibits potent anti-inflammatory properties in the acute phase of ischemic stroke, but its effect on microglia polarization is unknown. Thus, the objective of this study was to investigate the neuroprotective effects of DHA on rat brain following ischemia-reperfusion injury, and to investigate the mechanism by which DHA regulates microglia polarization. We administered DHA 5mg/kg intraperitoneally daily for 3 d following a transient middle cerebral artery occlusion reperfusion model in rats. The protective effects of DHA on cerebral ischemia-reperfusion injury were detected by TTC staining, HE staining, Nissler staining, and TUNEL staining. Quantitative real-time PCR, immunofluorescence, western blot, and enzyme-linked immunosorbent assay were used to detect the expression of M1 and M2 microglia-associated markers and PPARγ-mediated ERK/AKT signaling pathway proteins. We found that DHA significantly improved brain injury by decreasing the expression of the M1 phenotypic marker (iNOS, CD16) and increasing the expression of the M2 phenotypic marker (Arg-1, CD206). DHA also increased the expression of peroxisome proliferator-activated receptor gamma (PPARγ) mRNA and protein, increased the expression of the pathway protein AKT, and decreased the expression of ERK1/2. In addition, DHA promoted the expression of anti-inflammatory factor IL-10 and decreased the expression of pro-inflammatory factors TNF-α and IL-1β. However, the PPARγ antagonist GW9662 greatly blocked these beneficial effects. These results suggest that DHA may activate PPARγ to inhibit ERK and activate AKT signaling pathways to regulate microglia polarization, thereby reducing neuroinflammation and promoting neurological recovery to alleviate cerebral ischemia-reperfusion injury.

Sex differences in the inflammatory response to stroke

Ischemic stroke is a leading cause of morbidity and mortality and disproportionally affects women, in part due to their higher longevity. Older women have poorer outcomes after stroke with high rates of cognitive deficits, depression, and reduced quality of life. Post-stroke inflammatory responses are also sexually dimorphic and drive differences in infarct size and recovery. Factors that influence sex-specific immune responses can be both intrinsic and extrinsic. Differences in gonadal hormone exposure, sex chromosome compliment, and environmental/social factors can drive changes in transcriptional and metabolic profiles. In addition, how these variables interact, changes across the lifespan. After the onset of ischemic injury, necrosis and apoptosis occur, which activate microglia and other glial cells within the central nervous system, promoting the release of cytokines and chemokines and neuroinflammation. Cells involved in innate and adaptive immune responses also have dual functions after stroke as they can enhance inflammation acutely, but also contribute to suppression of the inflammatory cascade and later repair. In this review, we provide an overview of the current literature on sex-specific inflammatory responses to ischemic stroke. Understanding these differences is critical to identifying therapeutic options for both men and women.

The Study of the Association of Polymorphisms in LSP1, GPNMB, PDPN, TAGLN, TSPO, and TUBB6 Genes with the Risk and Outcome of Ischemic Stroke in the Russian Population

To date, there has been great progress in understanding the genetic basis of ischemic stroke (IS); however, several aspects of the condition remain underexplored, including the influence of genetic factors on post-stroke outcomes and the identification of causative loci. We proposed that an analysis of the results obtained from animal models of brain ischemia could be helpful. To this end, we developed a bioinformatic approach for exploring single-nucleotide polymorphisms (SNPs) in human orthologs of rat genes expressed differentially after induced brain ischemia. Using this approach, we identified and analyzed 11 SNPs from 6 genes in 553 Russian individuals (331 patients with IS and 222 controls). We assessed the association of SNPs with the risk of IS and IS outcomes. We found that the SNPs rs858239 (GPNMB), rs907611 (LSP1), and rs494356 (TAGLN) were associated with different parameters of IS functional outcomes. In addition, the SNP rs1261025 (PDPN) was associated significantly with IS itself (p = 0.0188, recessive model). All these associations were demonstrated for the first time. Analysis of the literature suggests that they should be characterized as being inflammation related. This supports the pivotal role of inflammation in both the incidence of stroke and post-stroke outcomes. We believe the findings reported here will help with stroke prognosis in the future.

QiShen YiQi and its components attenuate acute thromboembolic stroke and carotid thrombosis by inhibition of CD62P/PSGL-1-mediated platelet-leukocyte aggregate formation

BACKGROUND

QiShen YiQi (QSYQ) dropping pill, a component-based Chinese medicine consisting of benefiting Qi (YQ) and activating blood (HX) components, has been reported to exert a beneficial effect on cerebral ischemia-induced stroke. However, its efficacy and pharmacological mechanism on acute thromboembolic stroke is not clear.

PURPOSE

This study is to explore the preventative effect and pharmacological mechanism of QSYQ and its YQ/HX components on the formation of platelet-leukocyte aggregation (PLA) in acute thromboembolic stroke.

STUDY DESIGN AND METHODS

In vivo thromboembolic stroke model and FeCl₃-induced carotid arterial occlusion models were used. Immunohistochemistry, Western blot, RT-qPCR, and flow cytometry experiments were performed to reveal the pharmacological mechanisms of QSYQ and its YQ/HX components.

RESULTS

In thromboembolic stroke rats, QSYQ significantly attenuated infarct area, improved neurological recovery, reduced PLA formation, and inhibited P-selection (CD62P)/ P-selectin glycoprotein ligand-1 (PSGL-1) expressions. The YQ component preferentially down-regulated PSGL-1 expression in leukocyte, while the HX component preferentially down-regulated CD62P expression in platelet. In carotid arterial thrombosis mice, QSYQ and its YQ/HX components inhibited thrombus formation, prolonged vessel occlusion time, reduced circulating leukocytes and P-selectin expression. PLA formation and platelet/leukocyte adhesion to endothelial cell were also inhibited by QSYQ and its YQ/HX components in vitro.

CONCLUSION

QSYQ and YQ/HX components attenuated thromboembolic stroke and carotid thrombosis by decreasing PLA formation via inhibiting CD62P/PSGL-1 expressions. This study shed a new light on the prevention of thromboembolic stroke.

Mechanical Thrombectomy for Acute Ischemic Stroke

OBJECTIVE

Endovascular stroke therapy has greatly improved the ability to treat the deadliest and most disabling form of acute ischemic stroke. This article summarizes some of the recent innovations in this field and discusses likely future developments.

LATEST DEVELOPMENTS

At present, there is robust activity to improve all facets of care for patients with large vessel occlusion stroke, including better prehospital routing, more efficient in-hospital screening, expanding indications for thrombectomy eligibility, innovating novel thrombectomy devices, and improving the effects of recanalization on clinical outcomes. In addition, the integration of endovascular stroke therapy (EVT)-an emergent and frequently off-hours procedure that requires a specialized team of nurses, technologists, and physicians-into acute stroke care has transformed referral patterns, hospital accreditation pathways, and physician practices. The eligibility for the procedure will potentially continue to grow to include patients screened without advanced imaging, larger core infarcts, and more distal occlusions.

ESSENTIAL POINTS

In this review, we discuss the current state of EVT and its implications for practice, and present three cases that highlight some of the directions in which the field is moving.

Influencing factors of futile recanalization after endovascular therapy for cerebral infarction with posterior circulation occlusion of large vessels: a retrospective study

BACKGROUND

The optimal treatment for cerebral infarction caused by posterior circulation occlusion of large vessels has not yet been determined. Intravascular interventional therapy is an important treatment for cerebral infarction with posterior circulation occlusion of large vessels. However, endovascular therapy (EVT) of some posterior circulation cerebrovascular is ineffective and eventually become futile recanalization. Therefore, we performed a retrospective study to explore the factors influencing futile recanalization after EVT in patients with posterior circulation large-vessel occlusion.

METHODS

Eighty-six patients with acute cerebral infarction and posterior circulation large vessel occlusion after intravascular intervention were divided into two groups according to their modified Rankin scale (mRS) scores after 3 months: group 1, mRS scores less than or equal to 3 (the effective recanalization group); group 2, mRS scores greater than 3 (the ineffective recanalization group). The basic clinical data, imaging index scores, time from onset to recanalization, and operation time between the two groups were compared and analyzed. Logistic regression was used to analyze the factors influencing indicators of good prognosis, and the ROC curve and Youden index were used to determine the best cutoff value.

RESULTS

Between the two groups, there were significant differences in the posterior circulation CT angiography (pc-CTA) scores, GCS scores, pontine midbrain index scores, time from discovery to recanalization, operation time, NIHSS score and incidence of gastrointestinal bleeding. The logistic regression revealed that the NIHSS score and time from discovery to recanalization were associated with good prognoses.

CONCLUSION

NIHSS score and recanalization time were independent influencing factors of ineffective recanalization of cerebral infarctions caused by posterior circulation occlusion. EVT is relatively effective for cerebral infarction caused by posterior circulation occlusion when the NIHSS score is less than or equal to 16 and the time from onset to recanalization is less than or equal to 570 min.

Mild Traumatic Brain Injury Induces Time- and Sex-Dependent Cerebrovascular Dysfunction and Stroke Vulnerability

Mild traumatic brain injury (mTBI) produces subtle cerebrovascular impairments that persist over time and promote increased ischemic stroke vulnerability. We recently established a role for vascular impairments in exacerbating stroke outcomes 1 week after TBI, but there is a lack of research regarding long-term impacts of mTBI-induced vascular dysfunction, as well as a significant need to understand how mTBI promotes stroke vulnerability in both males and females. Here, we present data using a mild closed head TBI model and an experimental stroke occurring either 7 or 28 days later in both male and female mice. We report that mTBI induces larger stroke volumes 7 days after injury, however, this increased vulnerability to stroke persists out to 28 days in female but not male mice. Importantly, mTBI-induced changes in blood-brain barrier permeability, intravascular coagulation, angiogenic factors, total vascular area, and glial expression were differentially altered across time and by sex. Taken together, these data suggest that mTBI can result in persistent cerebrovascular dysfunction and increased susceptibility to worsened ischemic outcomes, although these dysfunctions occur differently in male and female mice.

Association of platelet-to-neutrophil ratios with 1-year outcome and mortality in patients with acute ischemic stroke

BACKGROUND

Platelet-neutrophil crosstalk is being increasingly recognized as a driver of inflammation and thrombosis in patients with ischemic stroke. The aim of this study was to investigate the potential of PNR value in predicting the long-term prognosis and evaluate whether or not an available and routine blood cell biomarker could help predict the long-term neurological function and mortality in AIS patients.

METHODS

A total of 718 patients with suspected acute ischemic stroke were involved and followed up for 1 year by standard telephone interview or reexamination. Kaplan-Meier curve, Univariate and Multivariate Cox Regression were analyzed using Statistical Packages for Social Sciences.

RESULTS

ROC curve for PNR to evaluate 1-year outcomes was analyzed and the area under the curve (AUC) was 0.659 (P < 0.001). The cutoff point was observed at 38.30, with a sensitivity of 53.09 % and a specificity of 71.25 %. Moreover, patients in PNR ≤ 38.30 were more likely to have more serious NIHSS on admission, 1-year mRS and higher 1-year mortality (P < 0.001, respectively). The 1-year mortality in the low PNR group was significantly higher than that of the high PNR group (log-rank tests: P < 0.0001). Age, NIHSS, RBC and PNR were combined into model B which significantly increased the AUC value from 0.736 to 0.888 compared to model A (including Age, NIHSS and RBC).

CONCLUSION

PNR may serve as a readily assessable biomarker for early predicting neurological deterioration and the long-term prognosis of AIS. The nomogram that included age, NIHSS, PNR and RBC may be a useful predictive tool for 1-year mortality.

Blocking of PI3-kinase beta protects against cerebral ischemia/reperfusion injury by reducing platelet activation and downstream microvascular thrombosis in rats

Phosphoinositide 3-kinase beta (PI3Kβ) plays an important role in platelet activation and thrombosis, but its role in stroke pathology remains unknown. In this study, we investigated whether inhibition of PI3Kβ protects against cerebral ischemia/reperfusion (I/R) injury by preventing circulating platelet activation and downstream microvascular thrombosis. We used a rat intraluminal filament model of transient middle cerebral artery occlusion (tMCAO) because the rapid restoration of cerebral blood flow to the ischemic area in both tMCAO and endovascular thrombectomy provides clinical relevance for this model. The results showed that TGX221, a selective PI3Kβ inhibitor, treatment immediately before the onset of reperfusion dose-dependently reduced infarct volume and improved neurological function. The protective effects were associated with blocking platelet activation and thrombotic response, thereby reducing downstream microvascular thrombosis, and maintaining reperfusion efficiency. These results suggest that PI3Kβ might be a promising target for treating downstream microvascular thrombosis induced by cerebral I/R injury and offer a novel adjunctive treatment to improve reperfusion therapy for acute ischemic stroke.

Hyperacute immune responses associate with immediate neuropathology and motor dysfunction in large vessel occlusions

OBJECTIVE

Despite successful endovascular therapy, a proportion of stroke patients exhibit long-term functional decline, regardless of the cortical reperfusion. Our objective was to evaluate the early activation of the adaptive immune response and its impact on neurological recovery in patients with large vessel occlusion (LVO).

METHODS

Nineteen (13 females, 6 males) patients with acute LVO were enrolled in a single-arm prospective cohort study. During endovascular therapy (EVT), blood samples were collected from pre and post-occlusion, distal femoral artery, and median cubital vein (controls). Cytokines, chemokines, cellular and functional profiles were evaluated with immediate and follow-up clinical and radiographic parameters, including cognitive performance and functional recovery.

RESULTS

In the hyperacute phase (within hours), adaptive immune activation was observed in the post-occlusion intra-arterial environment (post). Ischemic vascular tissue had a significant increase in T-cell-related cytokines, including IFN-γ and MMP-9, while GM-CSF, IL-17, TNF-α, IL-6, MIP-1a, and MIP-1b were decreased. Cellularity analysis revealed an increase in inflammatory IL-17+ and GM-CSF+ helper T-cells, while natural killer (NK), monocytes and B-cells were decreased. A correlation was observed between hypoperfused tissue, infarct volume, inflammatory helper, and cytotoxic T-cells. Moreover, helper and cytotoxic T-cells were also significantly increased in patients with improved motor function at 3 months.

INTERPRETATION

We provide evidence of the activation of the inflammatory adaptive immune response during the hyperacute phase and the association of pro-inflammatory cytokines with greater ischemic tissue and worsening recovery after successful reperfusion. Further characterization of these immune pathways is warranted to test selective immunomodulators during the early stages of stroke rehabilitation.

Brush sign and collateral supply as potential markers of large infarct growth after successful thrombectomy

OBJECTIVES

To investigate the relationships between brush sign and cerebral collateral status on infarct growth after successful thrombectomy.

METHODS

HIBISCUS-STROKE cohort includes acute ischemic stroke patients treated with thrombectomy after MRI triage and undergoing a day-6 MRI including FLAIR images to quantify final infarct volume (FIV). Successful reperfusion was defined as a modified thrombolysis in cerebral infarction score  ≥ 2B. Infarct growth was calculated by subtracting FIV from baseline ischemic core after co-registration and considered large (LIG) when  > 11.6 mL. Brush sign was assessed on T2*-weighted-imaging and collaterals were assessed using the hypoperfusion intensity ratio, which is the volume of Time-To-Tmax (Tmax)  ≥ 10 s divided by the volume of Tmax  ≥  6 s. Good collaterals were defined by a hypoperfusion intensity ratio  < 0.4.

RESULTS

One hundred and twenty-nine patients were included, of whom 45 (34.9%) had a brush sign and 63 (48.8%) good collaterals. Brush sign was associated with greater infarct growth (p = 0.01) and larger FIV (p = 0.02). Good collaterals were associated with a smaller baseline ischemic core (p < 0.001), larger penumbra (p = 0.04), and smaller FIV (p < 0.001). Collateral status was not significantly associated with brush sign (p = 0.20) or with infarct growth (p = 0.67). Twenty-eight (22.5%) patients experienced LIG. Univariate regressions indicated that brush sign (odds ratio (OR) = 4.8; 95% confidence interval (CI): [1.9;13.3]; p = 0.004) and hemorrhagic transformation (OR = 1.7; 95%CI: [1.2;2.6]; p = 0.04) were predictive of LIG. In multivariate regression, only the brush sign remained predictive of LIG (OR = 5.2; 95%CI: [1.8-16.6], p = 0.006).

CONCLUSIONS

Brush sign is a predictor of LIG after successful thrombectomy and cerebral collateral status is not.

KEY POINTS

• Few predictors of ischemic growth are known in ischemic stroke patients achieving successful mechanical thrombectomy. • Our results suggest that the brush sign-a surrogate marker of severe hypoperfusion-is independently associated with large ischemic growth (> 11.6 mL) after successful thrombectomy whereas cerebral collateral status does not.

The role of traditional herbal medicine for ischemic stroke: from bench to clinic-A critical review

BACKGROUND

Ischemic stroke (IS) is a leading cause of death and severe long-term disability worldwide. Over the past few decades, considerable progress has been made in anti-ischemic therapies. However, IS remains a tremendous challenge, with favourable clinical outcomes being generally difficult to achieve from candidate drugs in preclinical phase testing. Traditional herbal medicine (THM) has been used to treat stroke for over 2,000 years in China. In modern times, THM as an alternative and complementary therapy have been prescribed in other Asian countries and have gained increasing attention for their therapeutic effects. These millennia of clinical experience allow THM to be a promising avenue for improving clinical efficacy and accelerating drug discovery.

PURPOSE

To summarise the clinical evidence and potential mechanisms of THMs in IS.

METHODS

A comprehensive literature search was conducted in seven electronic databases, including PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, the Chinese National Knowledge Infrastructure, the VIP Information Database, the Chinese Biomedical Literature Database, and the Wanfang Database, from inception to 17 June 2022 to examine the efficacy and safety of THM for IS, and to investigate experimental studies regarding potential mechanisms.

RESULTS

THM is widely prescribed for IS alone or as adjuvant therapy. In clinical trials, THM is generally administered within 72 h of stroke onset and are continuously prescribed for over 3 months. Compared with Western medicine (WM), THM combined with routine WM can significantly improve neurological function defect scores, promote clinical total effective rate, and accelerate the recovery time of stroke with fewer adverse effects (AEs). These effects can be attributed to multiple mechanisms, mainly anti-inflammation, antioxidative stress, anti-apoptosis, brain blood barrier (BBB) modulation, inhibition of platelet activation and thrombus formation, and promotion of neurogenesis and angiogenesis.

CONCLUSIONS

THM may be a promising candidate for IS management to guide clinical applications and as a reference for drug development.

Neutrophil extracellular traps: A novel target for the treatment of stroke

Stroke is a threatening cerebrovascular disease caused by thrombus with high morbidity and mortality rates. Neutrophils are the first to be recruited in the brain after stroke, which aggravate brain injury through multiple mechanisms. Neutrophil extracellular traps (NETs), as a novel regulatory mechanism of neutrophils, can trap bacteria and secret antimicrobial molecules, thereby degrading pathogenic factors and killing bacteria. However, NETs also exacerbate certain non-infectious diseases by activating autoimmune or inflammatory responses. NETs have been found to play important roles in the pathological process of stroke in recent years. In this review, the mechanisms of NETs formation, the physiological roles of NETs, and the dynamic changes of NETs after stroke are summarized. NETs participate in stroke through various mechanisms. NETs promote the coagulation cascade and interact with platelets to induce thrombosis. tPA induces the degranulation of neutrophils to form NETs, leading to hemorrhagic transformation and thrombolytic resistance. NETs aggravate stroke by mediating inflammation, atherosclerosis and vascular injury. In addition, the regulation of NETs in stroke, the potential of NETs as biomarker and the treatment of stroke targeting NETs are discussed. The increasing evidences suggest that NETs may be a potential target for stroke treatment. Inhibition of NETs formation or promotion of NETs degradation plays protective effects in stroke. However, how to avoid the adverse effects of NETs-targeted therapy deserves further study. In summary, this review provides a reference for the pathogenesis, drug targets, biomarkers and drug development of NETs in stroke.

Neutrophil Extracellular Traps in Cerebral Ischemia/Reperfusion Injury: Friend and Foe

Cerebral ischemic injury, one of the leading causes of morbidity and mortality worldwide, triggers various central nervous system (CNS) diseases, including acute ischemic stroke (AIS) and chronic ischemia-induced Alzheimer's disease (AD). Currently, targeted therapies are urgently needed to address neurological disorders caused by cerebral ischemia/reperfusion injury (CI/RI), and the emergence of neutrophil extracellular traps (NETs) may be able to relieve the pressure. Neutrophils are precursors to brain injury following ischemic stroke and exert complicated functions. NETs extracellularly release reticular complexes of neutrophils, i.e., double-stranded DNA (dsDNA), histones, and granulins. Paradoxically, NETs play a dual role, friend and foe, under different conditions, for example, physiological circumstances, infection, neurodegeneration, and ischemia/reperfusion. Increasing evidence indicates that NETs exert anti-inflammatory effects by degrading cytokines and chemokines through protease at a relatively stable and moderate level under physiological conditions, while excessive amounts of NETs release (NETosis) irritated by CI/RI exacerbate the inflammatory response and aggravate thrombosis, disrupt the blood-brain barrier (BBB), and initiates sequential neuron injury and tissue damage. This review provides a comprehensive overview of the machinery of NETs formation and the role of an abnormal cascade of NETs in CI/RI, as well as other ischemia-induced neurological diseases. Herein, we highlight the potential of NETs as a therapeutic target against ischemic stroke that may inspire translational research and innovative clinical approaches.

Neutrophil dynamics and inflammaging in acute ischemic stroke: A transcriptomic review

Stroke is among the leading causes of death and disability worldwide. Restoring blood flow through recanalization is currently the only acute treatment for cerebral ischemia. Unfortunately, many patients that achieve a complete recanalization fail to regain functional independence. Recent studies indicate that activation of peripheral immune cells, particularly neutrophils, may contribute to microcirculatory failure and futile recanalization. Stroke primarily affects the elderly population, and mortality after endovascular therapies is associated with advanced age. Previous analyses of differential gene expression across injury status and age identify ischemic stroke as a complex age-related disease. It also suggests robust interactions between stroke injury, aging, and inflammation on a cellular and molecular level. Understanding such interactions is crucial in developing effective protective treatments. The global stroke burden will continue to increase with a rapidly aging human population. Unfortunately, the mechanisms of age-dependent vulnerability are poorly defined. In this review, we will discuss how neutrophil-specific gene expression patterns may contribute to poor treatment responses in stroke patients. We will also discuss age-related transcriptional changes that may contribute to poor clinical outcomes and greater susceptibility to cerebrovascular diseases.

Ischemic post-conditioning in acute ischemic stroke thrombectomy: A phase-I duration escalation study

Background

Previous experimental studies have found that ischemic post-conditioning exhibits neuroprotective effects by alleviating ischemia-reperfusion injury in an acute ischemic stroke model, and its efficacy is thought to be related to the duration of ischemic post-conditioning. However, ischemic post-conditioning has not been used in patients with acute ischemic stroke. This study aims to determine the safety, tolerability, and maximum tolerable duration of ischemic post-conditioning in patients with acute ischemic stroke receiving mechanical thrombectomy.

Methods

Patients with acute ischemic stroke with unilateral middle cerebral artery M1 segment occlusion eligible for mechanical thrombectomy will be enrolled. We adopt a 3 + 3 dose-escalation design with a duration escalation schedule of 0, 1, 2, 3, 4, and 5 min × 4 cycles for the ischemic post-conditioning study. After successful reperfusion following mechanical thrombectomy, the balloon for ischemic post-conditioning will be inflated at the site proximal to the culprit lesion four times for 0–5 min with low-pressure (3–4 atmospheres) inflations, each separated by 0–5 min of reflow. We pre-defined the major responses (vessel perforation or rupture, reocclusion of the culprit vessel after ischemic post-conditioning, vessel dissection, severe vasospasm, ischemic post-conditioning related thrombotic events, and rupture of the balloon used for ischemic post-conditioning) as the stopping rules. Each patient will undergo a rigorous evaluation to determine the safety, tolerability, and maximum tolerable duration of ischemic post-conditioning.

Discussion

This will be the first clinical study to ascertain the safety and tolerability of ischemic post-conditioning in patients with acute ischemic stroke receiving mechanical thrombectomy. The maximum tolerable duration obtained in this study will also serve as a starting point for future studies on the efficacy of ischemic post-conditioning.

Clinical trial registration

[https://clinicaltrials.gov], identifier [NCT05153655].

Network pharmacology approach to investigate the multitarget mechanisms of Zhishi Rhubarb Soup on acute cerebral infarction

CONTEXT

Zhishi Rhubarb Soup (ZRS) is a traditional Chinese medicine formula used in the clinic to treat acute cerebral infarction (ACI) for many years. However, the exact mechanism of the treatment remains unclear.

OBJECTIVE

This study elucidates the multitarget mechanisms underlying the effects of ZRS on ACI using network pharmacology analysis and verify its effect by performing animal experiments.

MATERIALS AND METHODS

Using the network pharmacology approach, the multiple components, critical targets and potential mechanisms of ZRS against ACI were investigated. Six herbal names of ZRS and 'acute cerebral infarction' were used as keywords to search the relevant databases. In addition, we established the MCAO model to verify the results of network pharmacology enrichment analysis. ZRS (10 g crude drug/kg) was gavaged once per day for 7 consecutive days beginning 3 h after model establishment. After ZRS treatment, TTC staining, Western blot analysis, IHC and ELISA were conducted to further explore the mechanism of ZRS intervention in ACI.

RESULTS

The network pharmacology approach identified 69 key targets, 10 core genes and 169 signalling pathways involved in the treatment of ACI with ZRS. In vivo experiment showed that ZRS treatment significantly reduced cerebral infarction volume (42.76%). It also reduced the expression level of AGE, RAGE and P65; and inhibited the expression of inflammatory MMP-9 and IFN-γ.

CONCLUSIONS

This study demonstrated that ZRS improved cerebral ischaemic injury by inhibiting neuroinflammation partly via the AGE-RAGE signalling pathway. It provides a theoretical basis for the clinical application of ZRS in the treatment of ACI.

Wasp venom from Vespa magnifica acts as a neuroprotective agent to alleviate neuronal damage after stroke in rats

CONTEXT

Acute ischaemic stroke (AIS) is a major cause of disability and death, which is a serious threat to human health and life. Wasp venom extracted from Vespa magnifica Smith (Vespidae) could treat major neurological disorders.

OBJECTIVE

This study investigated the effects of wasp venom on AIS in rats.

MATERIAL AND METHODS

We used a transient middle cerebral artery occlusion (MCAO) model in Sprague-Dawley rats (260-280 g, n = 8-15) with a sham operation group being treated as negative control. MCAO rats were treated with wasp venom (0.05, 0.2 and 0.6 mg/kg, i.p.) using intraperitoneal injection. After treatment 48 h, behavioural tests, cortical blood flow (CBF), TTC staining, H&E staining, Nissl staining, TUNEL assay, immunohistochemistry (IHC) and ELISA were employed to investigate neuroprotective effects of wasp venom.

RESULTS

Compared with the MCAO group, wasp venom (0.6 mg/kg) improved neurological impairment, accelerated CBF recovery (205.6 ± 52.92 versus 216.7 ± 34.56), reduced infarct volume (337.1 ± 113.2 versus 140.7 ± 98.03) as well as BBB permeability as evidenced by changes in claudin-5 and AQP4. In addition, function recovery of stroke by wasp venom treatment was associated with a decrease in TNF-α, IL-1β, IL-6 and inhibition activated microglia as well as apoptosis. Simultaneously, the wasp venom regulated the angiogenesis factors VEGF and b-FGF in the brain.

CONCLUSIONS

Wasp venom exhibited a potential neuroprotective effect for AIS. In the future, we will focus on determining whether the observed actions were due to a single compound or the interaction of multiple components of the venom.

Exosomes-based therapy of stroke, an emerging approach toward recovery

Based on clinical observations, stroke is touted as one of the specific pathological conditions, affecting an individual’s life worldwide. So far, no effective treatment has been introduced to deal with stroke post-complications. Production and release of several neurotrophic factors by different cells exert positive effects on ischemic areas following stroke. As a correlate, basic and clinical studies have focused on the development and discovery of de novo modalities to introduce these factors timely and in appropriate doses into the affected areas. Exosomes (Exo) are non-sized vesicles released from many cells during pathological and physiological conditions and participate in intercellular communication. These particles transfer several arrays of signaling molecules, like several neurotrophic factors into the acceptor cells and induce specific signaling cascades in the favor of cell bioactivity. This review aimed to highlight the emerging role of exosomes as a therapeutic approach in the regeneration of ischemic areas.

Ischemic stroke: From pathological mechanisms to neuroprotective strategies

Ischemic stroke (IS) has complex pathological mechanisms, and is extremely difficult to treat. At present, the treatment of IS is mainly based on intravenous thrombolysis and mechanical thrombectomy, but they are limited by a strict time window. In addition, after intravenous thrombolysis or mechanical thrombectomy, damaged neurons often fail to make ideal improvements due to microcirculation disorders. Therefore, finding suitable pathways and targets from the pathological mechanism is crucial for the development of neuroprotective agents against IS. With the hope of making contributions to the development of IS treatments, this review will introduce (1) how related targets are found in pathological mechanisms such as inflammation, excitotoxicity, oxidative stress, and complement system activation; and (2) the current status and challenges in drug development.