Endothelial dysfunction and damage underlie cerebrovascular disease and ischemic stroke. We undertook corneal confocal microscopy (CCM) to quantify corneal endothelial cell and nerve morphology in 146 patients with an acute ischemic stroke and 18 age-matched healthy control participants. Corneal endothelial cell density was lower (P < 0.001) and endothelial cell area (P < 0.001) and perimeter (P < 0.001) were higher, whilst corneal nerve fibre density (P < 0.001), corneal nerve branch density (P < 0.001) and corneal nerve fibre length (P = 0.001) were lower in patients with acute ischemic stroke compared to controls. Corneal endothelial cell density, cell area and cell perimeter correlated with corneal nerve fiber density (P = 0.033, P = 0.014, P = 0.011) and length (P = 0.017, P = 0.013, P = 0.008), respectively. Multiple linear regression analysis showed a significant independent association between corneal endothelial cell density, area and perimeter with acute ischemic stroke and triglycerides. CCM is a rapid non-invasive ophthalmic imaging technique, which could be used to identify patients at risk of acute ischemic stroke.

Stroke attacks were found to be present at a younger age in patients from Southeast Asia (SE) and the Middle East (ME) resident in the state of Qatar. Extracellular vesicles (EVs), which are small membrane vesicles with pro-thrombotic properties, may contribute to the high risk of stroke in this population. Thus, total and cell-specific medium size EVs were counted by flow cytometry in platelet-free plasma from healthy volunteers and patients with transient ischemic attacks (TIA) and acute ischemic stroke (AIS) from SE and ME. Acutely, within 48 h of attacks, there was an increase in total endothelial EVs in TIA (6.73 ± 1.77; P = 0.0156; n = 21) and AIS (11.23 ± 1.95; P = 0.0007; n = 66) patients compared to controls (2.04 ± 0.78; n = 24). Similar increases were also evident in EVs originating from platelets, erythrocytes, granulocytes, and leukocytes. Compared to controls, there was also an increase in EVs derived from activated endothelial cells, platelets, granulocytes, leukocytes, and pro-coagulant EVs (Annexin V+) at 5 and 30-days following the acute events, while a decrease was observed in erythrocyte-derived EVs. This is the first study characterizing EVs in TIA and AIS patients from ME and SE showing an increase in EVs associated with endothelial and platelet cell activation, which may contribute to the elevated risk of stroke at a younger age in this population.

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Asymptomatic small vessel disease (SVD), including white matter hyperintensities (WMHIs), periventricular hyperintensities (PVHIs), silent stroke (SS), and cerebral microbleeds (CMBs), increases the risk of stroke. There are limited studies of SVD in subjects from the Middle East and Southeast Asia (SA). All patients admitted to stroke service between 2014 and 2015 were reviewed for presence of "pre-existing" SVD. Stroke mimics with no previous history of stroke were used as controls. There were 1727 patients admitted with stroke. Analysis was done on 988 subjects (914 strokes and 74 controls) who had MRI scan done. Pre-existing SVD was seen in 642 (64.9%) patients (WMHIs 19.6%, PVHIs 33.2%, SS 51.4%, and CMBs 22%). Silent strokes were significantly more common with ischemic stroke (IS) compared to intracranial hemorrhage (ICH) (62.0 vs 34.3%, p < 0.001). CMBs were more in ICH compared to IS (42.9 vs 23.1%, p < 0.001). The risk of developing CMBs among Far Eastern (FE) patients was 1.58 times more (p = 0.07), while 1.48 times more in Arabs (AR) (p = 0.026) compared to SA after adjusting for age. The risk of developing PVHIs was significantly higher in Arab compared to SA (odds ratio (OR) 1.43; p value = 0.021). Similarly, the risk of developing WMHIs was also significantly higher in AR patients (OR 1.6; p value = 0.009) compared to SA. The majority of ethnic AR, SA, and FE populations show pre-existing SVD on MRI. The advanced changes at a young age may be related to high prevalence of untreated risk factors and possibly as yet defined genetic and environmental factors.

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