The Need for New Biomarkers to Assist with Stroke Prevention and Prediction of Post-Stroke Therapy Based on Plasma-Derived Extracellular Vesicles.

The risk of having a stroke event doubles each decade after the age of 55. Therefore, it is of great interest to develop neurorestorative therapies of stroke which occurs mostly in elderly people. However, to date, patients at risk for these sequels of stroke are not duly diagnosed and treated due to the lack of reliable biomarkers. Extracellular vesicles (EVs) are lipid bilayer-delimited particles that are shed by the brain cells and are able to cross the blood-brain barrier and enter the blood stream; thus, they may be used to interrogate molecular and cellular events in the brain damaged area. In this review, we summarize the major molecular and cellular responses of astroglia and neurons to cerebral ischemia and assess their impact on post-stroke recovery and rehabilitation. In particular, we ask if EVs secreted by brain cells are responses to cerebral ischemia, and they may shed new light on the interplay between exosomes-mediated interactions between brain cells and the question of how to exploit it in order to predict the individual course of the disease and to introduce specific preventive or therapeutic strategies. Given these findings, we are left with two options: either to (i) transplant neuronal precursors into the damaged cortical area or (ii) to covert abundantly present proliferating astrocytes in the perilesional area into neurons by using recently developed genetic technologies. However, given the complexity of molecular and cellular responses to cerebral ischemia and our limited capabilities to restore brain structure and function, we are left with only one realistic aim: to invest more in prevention.