Lopez-Arcos, Eduardo

Ischaemic stroke is a leading cause of death and disability. Circulating extracellular vesicles (EVs) post-stroke may help brain endothelial cells (BECs) counter ischaemic injury. However data on how EVs from ischaemic stroke patients, considering injury severity, affect these cells are limited. The aims were to characterize the inflammatory and angiogenic components of circulating EVs in acute ischaemic stroke patients, considering stroke severity, and to investigate whether these circulating EVs differentially influence the proangiogenic properties and blood–brain barrier (BBB) integrity of human BECs. Eighteen ischaemic stroke patients (acute phase: 24–48 h) and nine controls matched by age, sex, and blood pressure were studied. Stroke severity was classified as severe (n = 9) or mild (n = 9). Plasma EVs were analysed for size, concentration, and protein markers (CD63, Alix, CD81, TSG101, HSP70), as well as proinflammatory and angiogenic proteins. EV uptake, cell viability, proangiogenic capacity, electrical resistance [TEER (transendothelial electrical resistance)], and dextran-70 kD permeability were assessed using human brain microvascular endothelial cells (hCMEC/D3). Stroke patients had lower EV concentrations than controls (p = 0.075), with mild-stroke patients having the smallest EVs. Stroke-derived EVs had higher levels of interleukin 6 (IL-6), tumour necrosis factor α (TNF-α), nitrotyrosine, and vascular endothelial growth factor (VEGF) but lower placental growth factor (PLGF) compared to controls. IL-6 was higher in mild strokes (p = 0.0025), and VEGF was higher in severe strokes (p = 0.048). EVs from severe-stroke cases enhanced proangiogenic capacity and minimally disrupted the BBB. Stroke severity influences EV number, size, and composition. EVs from severe strokes may promote BBB restoration and cerebral angiogenesis, suggesting their role in intercellular communication and homeostasis in ischaemic tissue. Key points - Ischaemic stroke is one of the leading causes of death worldwide. After an ischaemic stroke several physiological processes are triggered to recover the injured tissue. - Increasing evidence has suggested that extracellular vesicles (EVs) present in the bloodstream could play a role in brain recovery, but their specific impact, especially concerning stroke severity, was unclear. - This study demonstrates that plasma-derived EVs from first-ever ischaemic stroke patients have distinctive characteristics and effects over brain angiogenesis and blood–brain barrier (BBB) integrity. - Our study proposes that circulating EVs from patients with severe stroke may carry protective factors to initiate brain endothelial cell recovery after acute episodes. - These findings underscore the role of EVs as potential effectors of BBB recovery and biomarkers in severe ischaemic stroke.

Background and purpose: Systemic inflammation conveys information about ischaemic stroke prognosis. Growth factors with neurotrophic and angiogenesis‐regulating properties might provide additional information about sequelae. The prognostic performance of circulating vascular endothelial growth factor (VEGF), placental growth factor, interleukin 6 and C‐reactive protein measured after acute ischaemic stroke was evaluated. Methods: Blood samples were collected from n = 45 patients within 24–48 h of acute ischaemic stroke. The primary outcome was death or moderate to severe disability at 6 months (modified Rankin Scale >2). Logistic regression models were used to determine the area under the receiver operating characteristic curve (AUC). Correlation and principal component analyses were performed to examine interrelationships amongst biomarkers. Results: Vascular endothelial growth factor was elevated in ischaemic stroke patients who died or had moderate to severe disability at six months. Correlation analysis revealed interrelationships between VEGF and HbA1c, triglycerides, erythrocyte sedimentation rate and National Institutes of Health Stroke Scale and Rankin scores, whereas principal component analyses identified VEGF as a major loading factor that discriminated good from poor prognosis. There were no significant differences in AUC using each protein individually to identify patients who had modified Rankin Scale score >2 at 6 months (n = 15/41, AUC 0.61–0.74). However, the AUC increased significantly when combining VEGF with interleukin 6 and C‐reactive protein compared to the VEGF‐only model (AUC 0.92 vs. 0.67, p = 0.02). Conclusion: Circulating VEGF was elevated 24–48 h after acute ischaemic stroke and conveyed prognostic information about moderate to severe disability at 6 months.