Intracranial VCAM1 at time of mechanical thrombectomy predicts ischemic stroke severity

Regenerating Family Member 3 Alpha Is Predictive of Mortality Following Emergent Large Vessel Occlusion

Regenerating Family Member 3 Alpha (REG3A) is an antimicrobial protein secreted by the intestine and pancreas with additional immunomodulatory properties. Previously, we published that REG3A expression in ischemic stroke patient systemic blood, during mechanical thrombectomy (MT), is significantly associated with inflammatory cytokines and patient function on admission. This paper, however, did not investigate post-acute death rates. Therefore, we investigated plasma REG3A protein expression, during MT, in patients (n = 141) that survived or died within the end of the follow-up after MT. Subjects who died had significantly higher systemic plasma REG3A levels at the time of MT compared to survivors (p = 0.001). Age, sex, time from last known normal, and admission NIHSS were included as predictors to control for confounding variables and were all examined to determine their association in patient mortality. Logistic regression was used to demonstrate that higher odds of death were associated with increased REG3A levels (p = 0.002). REG3A demonstrated acceptable discrimination (AUC (95% CI): 0.669 (0.566-0.772) in predicting mortality. The overall model with age, sex, time from last known normal, and admission NIHSS discriminated well between survivors and those who died (AUC (95% CI): 0.784 (0.703-0.864)). In conclusion, REG3A could be promising as a biomarker to prognosticate stroke outcomes and stratify high-risk groups following acute ischemic stroke.

The differential proteomic response to ischemic stroke in appalachian subjects treated with mechanical thrombectomy

INTRODUCTION

The Appalachia region of North America is known to have significant health disparities, specifically, worse risk factors and outcomes for stroke. Appalachians are more likely to have comorbidities related to stroke, such as diabetes, obesity, and tobacco use, and are often less likely to have stroke interventions, such as mechanical thrombectomy (MT), for emergent large vessel occlusion (ELVO). As our Comprehensive Stroke Center directly serves stroke subjects from both Appalachian and non-Appalachian areas, inflammatory proteomic biomarkers were identified associated with stroke outcomes specific to subjects residing in Appalachia.

METHODS

There were 81 subjects that met inclusion criteria for this study. These subjects underwent MT for ELVO, and carotid arterial blood samples acquired at time of intervention were sent for proteomic analysis. Samples were processed in accordance with the Blood And Clot Thrombectomy Registry And Collaboration (BACTRAC; clinicaltrials.gov; NCT03153683). Statistical analyses were utilized to examine whether relationships between protein expression and outcomes differed by Appalachian status for functional (NIH Stroke Scale; NIHSS and Modified Rankin Score; mRS), and cognitive outcomes (Montreal Cognitive Assessment; MoCA).

RESULTS

No significant differences were found in demographic data or co-morbidities when comparing Appalachian to non-Appalachian subjects. However, time from stroke onset to treatment (last known normal) was significantly longer and edema volume significantly higher in patients from Appalachia. Further, when comparing Appalachian to non-Appalachian subjects, there were significant unadjusted differences in the NIHSS functional outcome. A comprehensive analysis of 184 proteins from Olink proteomic (92 Cardiometabolic and 92 Inflammation panels) showed that the association between protein expression outcomes significantly differed by Appalachian status for seven proteins for the NIHSS, two proteins for the MoCA, and three for the mRS.

CONCLUSION

Our study utilizes an ELVO tissue bank and registry to investigate the intracranial/intravascular proteomic environment occurring at the time of thrombectomy. We found that patients presenting from Appalachian areas have different levels of proteomic expression at the time of MT when compared to patients presenting from non-Appalachian areas. These proteins differentially relate to stroke outcome and could be used as prognostic biomarkers, or as targets for novel therapies. The identification of a disparate proteomic response in Appalachian patients provides initial insight to the biological basis for health disparity. Nevertheless, further investigations through community-based studies are imperative to elucidate the underlying causes of this differential response.

Inflammation biomarkers in the intracranial blood are associated with outcome in patients with ischemic stroke

BACKGROUND

Performing endovascular treatment (EVT) in patients with acute ischemic stroke (AIS) allows a port of entry for intracranial biological sampling.

OBJECTIVE

To test the hypothesis that specific immune players are molecular contributors to disease, outcome biomarkers, and potential targets for modifying AIS.

METHODS

We examined 75 subjects presenting with large vessel occlusion of the anterior circulation and undergoing EVT. Intracranial blood samples were obtained by microcatheter aspiration, as positioned for stent deployment. Peripheral blood samples were collected from the femoral artery. Plasma samples were quality controlled by electrophoresis and analyzed using a Mesoscale multiplex for targeted inflammatory and vascular factors.

RESULTS

We measured 37 protein biomarkers in our sample cohort. Through multivariate analysis, adjusted for age, intravenous thrombolysis, pretreatment National Institutes of Health Stroke Scale and Alberta Stroke Program Early CT scores, we found that post-clot blood levels of interleukin-6 (IL-6) were significantly correlated (adjusted P value <0.05) with disability assessed by the modified Rankin Scale (mRS) score at 90 days, with medium effect size. Chemokine (C-C) ligand 17 CCL17/TARC levels were inversely correlated with the mRS score. Examination of peripheral blood showed that these correlations did not reach statistical significance after correction. Intracranial biomarker IL-6 level was specifically associated with a lower likelihood of favorable outcome, defined as a mRS score of 0-2.

CONCLUSIONS

Our findings show a signature of blood inflammatory factors at the cerebrovascular occlusion site. The correlations between these acute-stage biomarkers and mRS score outcome support an avenue for add-on and localized immune modulatory strategies in AIS.

Blue light impairs cornea and corneal wound healing by downregulating VCAM1 partly

This study aimed to investigate the effects of long-term pollution from different wavelengths of light on the corneal epithelium (CE) and identify potential biomarkers. Rabbits were exposed to red, green, blue, white, and environmental light for 6 weeks. The CE was assessed using various techniques such as fluorescein sodium staining, transcriptome sequencing, electron microscopy, and molecular assays. In human corneal epithelial cells (hCECs), the downregulation of vascular cell adhesion molecule 1 (VCAM1) in response to blue light (BL) pollution was observed. This downregulation of VCAM1 inhibited migration, increased reactive oxygen species (ROS) levels, and apoptosis, and inhibited the AKT/p70 S6 kinase cascade in hCECs. Animal experiments confirmed that BL pollution caused similar effects on the rabbit cornea, including increased ROS production, apoptosis, delayed wound healing, and decreased VCAM1 expression. Overall, BL-induced VCAM1 downregulation may impair CE and wound healing and promote ROS and apoptosis in vitro and in vivo.

Proteomic advance of ischemic stroke: preclinical, clinical, and intervention

Ischemic stroke (IS) is the most common type of stroke and is characterized by high rates of mortality and long-term injury. The prediction and early diagnosis of IS are therefore crucial for optimal clinical intervention. Proteomics has provided important techniques for exploring protein markers associated with IS, but there has been no systematic evaluation and review of research that has used these techniques. Here, we review the differential proteins that have been found in cell- and animal- based studies and clinical trials of IS in the past 10 years; determine the key pathological proteins that have been identified in clinical trials; summarize the target proteins affected by interventions aimed at treating IS, with a focus on traditional Chinese medicine treatments. Overall, we clarify findings and problems that have been identified in recent proteomics research on IS and provide suggestions for improvements in this area. We also suggest areas that could be explored for determining the pathogenesis and developing interventions for IS.

Ozanimod differentially preserves human cerebrovascular endothelial barrier proteins and attenuates matrix metalloproteinase-9 activity following in vitro acute ischemic injury

Endothelial integrity is critical in mitigating a vicious cascade of secondary injuries following acute ischemic stroke (AIS). Matrix metalloproteinase-9 (MMP-9), a contributor to endothelial integrity loss, is elevated during stroke and is associated with worsened stroke outcome. We investigated the FDA-approved selective sphingosine-1-phosphate receptor 1 (S1PR1) ligand, ozanimod, on the regulation/activity of MMP-9 as well as endothelial barrier components [platelet endothelial cell adhesion molecule 1 (PECAM-1), claudin-5, and zonula occludens 1 (ZO-1)] in human brain microvascular endothelial cells (HBMECs) following hypoxia plus glucose deprivation (HGD). We previously reported that S1PR1 activation improves HBMEC integrity; however, mechanisms underlying S1PR1 involvement in endothelial cell barrier integrity have not been clearly elucidated. We hypothesized that ozanimod would attenuate an HGD-induced increase in MMP-9 activity that would concomitantly attenuate the loss of integral barrier components. Male HBMECs were treated with ozanimod or vehicle and exposed to 3 h of normoxia (21% O2) or HGD (1% O2). Immunoblotting, zymography, qRT-PCR, and immunocytochemical labeling techniques assessed processes related to MMP-9 and barrier markers. We observed that HGD acutely increased MMP-9 activity and reduced claudin-5 and PECAM-1 levels, and ozanimod attenuated these responses. In situ analysis, via PROSPER, suggested that attenuation of MMP-9 activity may be a primary factor in maintaining these integral barrier proteins. We also observed that HGD increased intracellular mechanisms associated with augmented MMP-9 activation; however, ozanimod had no effect on these select factors. Thus, we conclude that ozanimod has the potential to attenuate HGD-mediated decreases in HBMEC integrity in part by decreasing MMP-9 activity as well as preserving barrier properties.NEW & NOTEWORTHY We have identified a potential novel mechanism by which ozanimod, a selective sphingosine-1-phosphate receptor 1 (S1PR1) agonist, attenuates hypoxia plus glucose deprivation (HGD)-induced matrix metalloproteinase-9 (MMP-9) activity and disruptions in integral human brain endothelial cell barrier proteins. Our results suggest that ischemic-like injury elicits increased MMP-9 activity and alterations of barrier integrity proteins in human brain microvascular endothelial cells (HBMECs) and that ozanimod via S1PR1 attenuates these HGD-induced responses, adding to its therapeutic potential in cerebrovascular protection during the acute phase of ischemic stroke.

Neuroinflammatory Biomarkers in the Brain, Cerebrospinal Fluid, and Blood After Ischemic Stroke

The most frequent type of stroke, known as ischemic stroke (IS), is a significant global public health issue. The pathological process of IS and post-IS episodes has not yet been fully explored, but neuroinflammation has been identified as one of the key processes. Biomarkers are objective indicators used to assess normal or pathological processes, evaluate responses to treatment, and predict outcomes, and some biomarkers can also be used as therapeutic targets. After IS, various molecules are produced by different cell types, such as microglia, astrocytes, infiltrating leukocytes, endothelial cells, and damaged neurons, that participate in the neuroinflammatory response within the ischemic brain region. These molecules may either promote or inhibit neuroinflammation and may be released into extracellular spaces, including cerebrospinal fluid (CSF) and blood, due to reasons such as BBB damage. These neuroinflammatory molecules should be valued as biomarkers to monitor whether their expression levels in the blood, CSF, and brain correlate with the diagnosis and prognosis of IS patients or whether they have potential as therapeutic targets. In addition, although some molecules do not directly participate in the process of neuroinflammation, they have been reported to have potential diagnostic or therapeutic value against post-IS neuroinflammation, and these molecules will also be listed. In this review, we summarize the neuroinflammatory biomarkers in the brain, CSF, and blood after an IS episode and the potential value of these biomarkers for the diagnosis, treatment, and prognosis of IS patients.

Specific inflammatory profile of acute ischemic stroke patients with left atrial enlargement

Background

The inflammatory process underlying atrial myopathy may affect the inflammatory response activated in acute ischemic stroke (AIS).

Objectives

We aimed to assess whether left atrial enlargement (LAE) as a marker of atrial myopathy is associated with a different profile of circulating inflammatory markers in AIS patients.

Methods

HIBISCUS-STROKE is a cohort study including anterior circulation AIS patients treated with mechanical thrombectomy following MRI. Ten circulating inflammatory markers were measured at admission and 6, 24, and 48 h after admission. LAE was defined as a left atrial volume index (LAVi) ≥34 ml/m2. A multiple logistic regression model was performed to detect an independent association between the area under the curve (AUC) of these markers and LAE.

Results

We included 143 patients. Of them, 85 (59.4%) had LAE. On univariable analysis, we found that patients with LAE had higher soluble form suppression of tumorigenicity 2 (sST2), soluble tumor necrosis factor receptor I (sTNFR1), and vascular cellular adhesion molecule-1 (VCAM-1) AUC, were older, mostly female, had a higher National Institutes of Health Stroke Scale (NIHSS) score and blood glucose level at admission, had more often hypertension, and a cardioembolic source of AIS, such as atrial fibrillation, while they were less frequently current smokers and had a lower rate of tandem occlusion than patients without LAE. On multivariable analysis, we found that among circulating inflammatory markers, only high VCAM-1 (OR: 9.13, 95% CI: 3.21-25.9) and sST2 (OR: 3.40, 95% CI: 1.68-6.86) AUC remained associated with LAE.

Conclusions

High VCAM-1 and sST2 levels within the first 48 h are associated with LAE in AIS patients.

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.

Mechanism of ligusticum cycloprolactam against neuroinflammation based on network pharmacology and experimental verification

Ligustilide, a natural phthalide mainly derived from chuanxiong rhizomes and Angelica Sinensis roots, possesses anti-inflammatory activity, particularly in the context of the nervous system. However, its application is limited because of its unstable chemical properties. To overcome this limitation, ligusticum cycloprolactam (LIGc) was synthesized through structural modification of ligustilide. In this study, we combined network pharmacological methods with experimental verification to investigate the anti-neuroinflammatory effects and mechanisms of ligustilide and LIGc. Based on our network pharmacology analysis, we identified four key targets of ligustilide involved in exerting an anti-inflammatory effect, with the nuclear factor (NF)-κB signal pathway suggested as the main signalling pathway. To verify these results, we examined the expression of inflammatory cytokines and inflammation-related proteins, analysed the phosphorylation level of NF-κB, inhibitor of κBα (IκBα) and inhibitor of κB kinase α and β (IKKα+β), and evaluated the effect of BV2 cell-conditioned medium on HT22 cells in vitro. Our results, demonstrate for the first time that LIGc can downregulate the activation of the NF-κB signal pathway in BV2 cells induced by lipopolysaccharide, suppress the production of inflammatory cytokines and reduce nerve injury in HT22 cells mediated by BV2 cells. These findings suggest that LIGc inhibits the neuroinflammatory response mediated by BV2 cells, providing strong scientific support for the development of anti-inflammatory drugs based on natural ligustilide or its derivatives. However, there are some limitations to our current study. In the future, further experiments using in vivo models may provide additional evidence to support our findings.

Inflammatory-associated proteomic predictors of cognitive outcome in subjects with ELVO treated by mechanical thrombectomy

BACKGROUND

Emergent Large Vessel Occlusion (ELVO) stroke causes devastating vascular events which can lead to significant cognitive decline and dementia. In the subset of ELVO subjects treated with mechanical thrombectomy (MT) at our institution, we aimed to identify systemic and intracranial proteins predictive of cognitive function at time of discharge and at 90-days. These proteomic biomarkers may serve as prognostic indicators of recovery, as well as potential targets for novel/existing therapeutics to be delivered during the subacute stage of stroke recovery.

METHODS

At the University of Kentucky Center for Advanced Translational Stroke Sciences, the BACTRAC tissue registry (clinicaltrials.gov; NCT03153683) of human biospecimens acquired during ELVO stroke by MT is utilized for research. Clinical data are collected on each enrolled subject who meets inclusion criteria. Blood samples obtained during thrombectomy were sent to Olink Proteomics for proteomic expression values. Montreal Cognitive Assessments (MoCA) were evaluated with categorical variables using ANOVA and t-tests, and continuous variables using Pearson correlations.

RESULTS

There were n = 52 subjects with discharge MoCA scores and n = 28 subjects with 90-day MoCA scores. Several systemic and intracranial proteins were identified as having significant correlations to discharge MoCA scores as well as 90-day MoCA scores. Highlighted proteins included s-DPP4, CCL11, IGFBP3, DNER, NRP1, MCP1, and COMP.

CONCLUSION

We set out to identify proteomic predictors and potential therapeutic targets related to cognitive outcomes in ELVO subjects undergoing MT. Here, we identify several proteins which predicted MoCA after MT, which may serve as therapeutic targets to lessen post-stroke cognitive decline.

Endothelial Dysfunction and Parenchymal Hematoma in Ischemic Stroke Patients after Endovascular Thrombectomy

INTRODUCTION

Endothelial dysfunction (ED) may result in parenchymal injury and therefore worsen the outcomes of ischemic stroke. This study aimed to determine whether ED could predict parenchymal hematoma (PH) in ischemic stroke patients treated with endovascular thrombectomy (EVT).

METHODS

Patients with large artery occlusion in the anterior circulation and treated with EVT were prospectively enrolled from 2 stroke centers. Serum soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1, soluble E-selectin, and von Willebrand factor (vWF) were tested and summed to a standardized score to reflect the levels of ED. PH was diagnosed according to the Heidelberg Bleeding Classification.

RESULTS

Of the 325 enrolled patients (mean age, 68.6 years; 207 men), 41 (12.6%) developed PH. Patients with PH had higher concentrations of soluble E-selectin, vWF, and ED sum score. After adjusting for demographic characteristics, National Institutes of Health Stroke Scale score, pretreatment Alberta stroke program early computed tomography score, and other potential confounders, the increased ED burden was associated with PH (odds ratio, 1.432; 95% confidence interval, 1.031-1.988; p = 0.032). Similar significant results were found in the sensitivity analysis. The multiple-adjusted spline regression model showed a linear association between the total ED score and PH (p = 0.001 for linearity). Adding the ED score to the conventional model significantly improved the risk prediction of PH (net reclassification improvement = 25.2%, p = 0.001; integrated discrimination index = 2.9%; p = 0.001).

CONCLUSIONS

This study demonstrated that ED might be related to PH. Introducing the ED score could increase the reliability of the PH risk model for stroke patients treated with EVT.

Advancing Stroke Research on Cerebral Thrombi with Omic Technologies

Cerebrovascular diseases represent a leading cause of disability, morbidity, and death worldwide. In the last decade, the advances in endovascular procedures have not only improved acute ischemic stroke care but also conceded a thorough analysis of patients' thrombi. Although early anatomopathological and immunohistochemical analyses have provided valuable insights into thrombus composition and its correlation with radiological features, response to reperfusion therapies, and stroke etiology, these results have been inconclusive so far. Recent studies applied single- or multi-omic approaches-such as proteomics, metabolomics, transcriptomics, or a combination of these-to investigate clot composition and stroke mechanisms, showing high predictive power. Particularly, one pilot studies showed that combined deep phenotyping of stroke thrombi may be superior to classic clinical predictors in defining stroke mechanisms. Small sample sizes, varying methodologies, and lack of adjustments for potential confounders still represent roadblocks to generalizing these findings. However, these techniques hold the potential to better investigate stroke-related thrombogenesis and select secondary prevention strategies, and to prompt the discovery of novel biomarkers and therapeutic targets. In this review, we summarize the most recent findings, overview current strengths and limitations, and present future perspectives in the field.

Reverse Translation to Develop Post-stroke Therapeutic Interventions during Mechanical Thrombectomy: Lessons from the BACTRAC Trial

The majority of strokes, approximately 87%, are ischemic in etiology with the remaining hemorrhagic in origin. Emergent large vessel occlusions (ELVOs) are a subtype of ischemic stroke accounting for approximately 30-40% of acute large vessel blockages. Treatment for ELVOs focuses on recanalization of the occluded vessel by time-sensitive administration of tissue plasminogen activator (tPA) or thrombus removal using mechanical thrombectomy. Although a great deal of time and resources have focused on translational stroke research, little progress has been made in the area of identifying additional new treatments for stroke. Translational limitations include difficulty simulating human comorbid conditions in animal models, as well as the temporal nature of stroke pathology. The Blood And Clot Thrombectomy Registry And Collaboration represents an ongoing tissue registry for thrombectomy patients and includes collection of intracranial arterial blood, systemic arterial blood, thrombi, as well as a series of clinical and radiographic data points for analysis. This chapter will explore the methodologies employed and results obtained from studying BACTRAC-derived human biological specimens and how they can inform translational experimental design in animal studies.

Levels of adhesion molecules and clinical outcomes in patients with ischemic stroke after mechanical thrombectomy

Background and purpose

Data on adhesion molecule levels in patients treated with mechanical thrombectomy (MT) are scarce. We aimed to evaluate the association among adhesion molecule levels, symptomatic intracranial hemorrhage (sICH), and clinical outcome and to determine whether the sICH influences the association of adhesion molecules with functional outcome.

Methods

Patients with large artery occlusion in the anterior circulation and treated with MT were prospectively recruited. Adhesion molecules, such as soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1 (sVCAM-1), and soluble E-selectin (sE-selectin) were tested. An unfavorable outcome was defined as a 90-day modified Rankin Scale (mRS) score of 3–6. The sICH was diagnosed according to the Heidelberg Bleeding Classification within 72 h of endovascular treatment (EVT).

Results

Of the 310 enrolled patients (mean age, 68.5 years; 198 men), 46 (14.8%) experienced sICH and 173 (55.8%) experienced an unfavorable outcome at 90 days. After adjusting for potential confounders, patients with higher sVCAM-1 and sE-selectin levels had an increasing trend of sICH [4th quartile vs. 1st quartile for sVCAM-1; odds ratio (OR), 2.766, p = 0.085; sE-selectin; OR, 2.422, p = 0.086] and poor outcome (4th quartile vs. 1st quartile for sVCAM-1; OR, 2.614, p = 0.025; sE-selectin; OR, 2.325, p = 0.046). Furthermore, the sICH might partially mediate the worse functional outcome in patients with higher adhesion molecules levels (Sobel test, p < 0.001 for sVCAM-1 and p = 0.007 for sE-selectin).

Conclusions

There were significant relationships between levels of adhesion molecules and a 90-day poor outcome in patients with ischemic stroke treated with MT, which was partially mediated by sICH.

Plasma protein alterations during human large vessel stroke: A controlled comparison study

BACKGROUND

Stroke is a major cause of death and disability in the United States. Mechanical thrombectomy (MT) ¹ and tissue plasminogen activator are the current treatments for ischemic stroke, which have improved clinical outcomes. Despite these treatments, functional and cognitive deficits still occur demonstrating a need for predictive biomarkers for beneficial clinical outcomes which can be used as therapeutic targets for pharmacotherapy. The aim of this study compares the proteomic expression of systemic arterial blood collected at the time of MT to those from a matched cerebrovascular disease (CVD) control cohort.

METHODS

The Blood and Clot Thrombectomy Registry and Collaboration (BACTRAC) (clinicaltrials.gov NCT03153683) collects and banks arterial blood, both distal and proximal to the thrombus, from ischemic stroke subjects undergoing MT. Arterial blood from patients undergoing a diagnostic angiogram was also collected and banked as CVD controls. Changes in cardiometabolic and inflammatory proteins between stroke and CVD controls were analyzed via Olink Proteomics.

RESULTS

Proteins including ARTN, TWEAK, HGF, CCL28, FGF-5, CXCL9, TRANCE and GDNF were found to be decreased in stroke subjects when compared to CVD controls. CXCL1, CCL5, OSM, GP1BA, IL6, MMP-1, and CXCL5 were increased in stroke subjects when compared to CVD controls. These proteins were also significantly correlated to stroke outcome metrics such as NIHSS, infarct volume and MoCA scoring.

CONCLUSION

Overall, acute stroke patients had an increase in inflammatory proteins with a decrease in trophic proteins systemically compared to matched CVD controls. Using our CVD controls, proteins of interest were directly compared to stroke patients with the same cerebrovascular risk factors instead of statistically controlling for comorbidities. The novel methodology of matching an arterial blood CVD control group to a stroke group, as well as controlling for age and comorbid status add to the literature on prognostic stroke biomarkers, which are specific targets for future therapeutics.

sVCAM1 in the Hippocampus Contributes to Postoperative Cognitive Dysfunction in Mice by Inducing Microglial Activation Through the VLA-4 Receptor

Postoperative cognitive dysfunction (POCD) is a severe postsurgical complication, but its underlying mechanisms remain unclear. Neuroinflammation mediated by microglial activation plays a major role in POCD pathophysiology. Upregulation of vascular cell adhesion molecule 1 (VCAM1) on brain endothelial cells is closely correlated with microglial activation in the mouse hippocampus. However, the role of VCAM1 upregulation in microglial activation remains unknown. Soluble VCAM1 (sVCAM1) activates the very late antigen-4 (VLA-4) receptor under inflammatory conditions. Therefore, we hypothesized that sVCAM1 which is shed from VCAM1 contributes to POCD by triggering hippocampal microglial activation through the VLA-4 receptor. We found that VCAM1 and sVCAM1 expression in the mouse hippocampus was upregulated after surgery, and the upregulation was accompanied by hippocampal microglial activation. sVCAM1 levels in mouse and human serum were increased after surgery. Anti-VCAM1 treatment inhibited microglial activation, proinflammatory cytokine production, VLA-4 expression and P38 mitogen-associated protein kinase (MAPK) pathway activation and attenuated hippocampal-dependent cognitive dysfunction. In vitro, recombinant sVCAM1 promoted M1 polarization in BV2 cells, increased VLA-4 expression and activated the P38 MAPK pathway. These effects were reversed by VLA-4 receptor blockade. Anti-VLA-4 treatment ameliorated hippocampal-dependent cognitive dysfunction after surgery by inhibiting microglial activation, proinflammatory cytokine production and P38 pathway activation. In conclusion, increased sVCAM1 in the hippocampus is involved in microglial activation and cognitive dysfunction induced by surgery. Inhibiting the sVCAM1-VLA-4 interaction in microglia may be a therapeutic strategy for POCD.

Stroke Proteomics: From Discovery to Diagnostic and Therapeutic Applications

Stroke remains a leading cause of death and disability, with limited therapeutic options and suboptimal tools for diagnosis and prognosis. High throughput technologies such as proteomics generate large volumes of experimental data at once, thus providing an advanced opportunity to improve the status quo by facilitating identification of novel therapeutic targets and molecular biomarkers. Proteomics studies in animals are largely designed to decipher molecular pathways and targets altered in brain tissue after stroke, whereas studies in human patients primarily focus on biomarker discovery in biofluids and, more recently, in thrombi and extracellular vesicles. Here, we offer a comprehensive review of stroke proteomics studies conducted in both animal and human specimen and present our view on limitations, challenges, and future perspectives in the field. In addition, as a unique resource for the scientific community, we provide extensive lists of all proteins identified in proteomic studies as altered by stroke and perform postanalysis of animal data to reveal stroke-related cellular processes and pathways.

Isolation and identification of leukocyte populations in intracranial blood collected during mechanical thrombectomy

Using standard techniques during mechanical thrombectomy, the Blood and Clot Thrombectomy Registry and Collaboration (BACTRAC) protocol (NCT03153683) isolates intracranial arterial blood distal to the thrombus and proximal systemic blood in the carotid artery. We augmented the current protocol to study leukocyte subpopulations both distal and proximal to the thrombus during human stroke (n = 16 patients), and from patients with cerebrovascular disease (CVD) undergoing angiography for unrelated conditions (e.g. carotid artery stenosis; n = 12 patients). We isolated leukocytes for flow cytometry from small volume (<1 mL) intracranial blood and systemic blood (5-10 mL) to identify adaptive and innate leukocyte populations, in addition to platelets and endothelial cells (ECs). Intracranial blood exhibited significant increases in T cell representation and decreases in myeloid/macrophage representation compared to within-patient carotid artery samples. CD4⁺ T cells and classical dendritic cells were significantly lower than CVD controls and correlated to within-patient edema volume and last known normal. This novel protocol successfully isolates leukocytes from small volume intracranial blood samples of stroke patients at time of mechanical thrombectomy and can be used to confirm preclinical results, as well as identify novel targets for immunotherapies.

Long Non-Coding RNA-Mediated Competing Endogenous RNA Networks in Ischemic Stroke: Molecular Mechanisms, Therapeutic Implications, and Challenges

Ischemic stroke (IS) is a disease that is characterized by high mortality and disability. Recent studies have shown that LncRNA-mediated competing endogenous RNA (ceRNA) networks play roles in the occurrence and development of cerebral I/R injury by regulating different signaling pathways. However, no systematic analysis of ceRNA mechanisms in IS has been reported. In this review, we discuss molecular mechanisms of LncRNA-mediated ceRNA networks under I/R injury. The expression levels of LncRNAs, microRNAs (miRNAs), and messenger RNAs (mRNAs) and their effects in four major cell types of the neurovascular unit (NVU) are also involved. We further summarize studies of LncRNAs as biomarkers and therapeutic targets. Finally, we analyze the advantages and limitations of using LncRNAs as therapeutics for IS.

New Drug Targets to Prevent Death Due to Stroke: A Review Based on Results of Protein-Protein Interaction Network, Enrichment, and Annotation Analyses

This study used established biomarkers of death from ischemic stroke (IS) versus stroke survival to perform network, enrichment, and annotation analyses. Protein-protein interaction (PPI) network analysis revealed that the backbone of the highly connective network of IS death consisted of IL6, ALB, TNF, SERPINE1, VWF, VCAM1, TGFB1, and SELE. Cluster analysis revealed immune and hemostasis subnetworks, which were strongly interconnected through the major switches ALB and VWF. Enrichment analysis revealed that the PPI immune subnetwork of death due to IS was highly associated with TLR2/4, TNF, JAK-STAT, NOD, IL10, IL13, IL4, and TGF-β1/SMAD pathways. The top biological and molecular functions and pathways enriched in the hemostasis network of death due to IS were platelet degranulation and activation, the intrinsic pathway of fibrin clot formation, the urokinase-type plasminogen activator pathway, post-translational protein phosphorylation, integrin cell-surface interactions, and the proteoglycan-integrin extracellular matrix complex (ECM). Regulation Explorer analysis of transcriptional factors shows: (a) that NFKB1, RELA and SP1 were the major regulating actors of the PPI network; and (b) hsa-mir-26-5p and hsa-16-5p were the major regulating microRNA actors. In conclusion, prevention of death due to IS should consider that current IS treatments may be improved by targeting VWF, the proteoglycan-integrin-ECM complex, TGF-β1/SMAD, NF-κB/RELA and SP1.