Circulating Exosomes of Neuronal Origin as Potential Early Biomarkers for Development of Stroke

Stroke is one of the major causes of morbidity and mortality globally, with devastating effects. It is diagnosed mainly by clinical assessment and brain imaging; however, it is challenging to discriminate stroke from similar conditions with parallel presentations. While brain imaging provides detection of stroke infarcts, it does not provide useful information on the biology and prognosis of the underlying disease process. The complex pathophysiology of stroke infarcts is a barrier in developing sensitive diagnostic tools, which consequently has a detrimental effect on development of treatment regimens. Early diagnosis of stroke is vital for better management, but currently there is no diagnostic blood-based biomarker. The cargo of exosomes can give an insight into the physiological or pathophysiological status of the cell. Exosomes have gained great interest as a means of intercellular communication and recently have been explored as a potential biomarker tool. Circulating exosomes in the blood result from of a contribution from all tissues. The sub-population of exosomes released from brain cells circulating in body fluids are known as neuronal exosomes. This overview presents the vital diagnostic function that could be performed by circulating exosomes of neuronal origin in identifying the subtype of stroke, its severity, and the recovery stages. A number of potential biomarkers that are obtained from circulating exosomes have showed promising potential to function as stroke biomarkers; however, further work is needed to characterize the neuronal exosomes and its payload and to determine the pathways it uses in the complex pathophysiology of stroke. The identification is a subset of exosomal biomarkers that are specific to stroke will enhance the early detection and prognosis of the disease.