Extracellular vesicles-based theranostics for neurodegenerative diseases

With the accelerated aging of the global population, the incidence of neurodegenerative diseases (NDDs) is increasing year by year. Because of the presence of the blood–brain barrier (BBB), the low concentration of the biomarkers in peripheral blood and the low penetration rate of the drugs through BBB into brain hinders the development of diagnosis and treatment of NDDs. As an effective mediator to penetrate through BBB in both directions, extracellular vesicles (EVs) have attracted much attention in the early diagnosis and treatment of NDDs because of their superior performance as drug carriers and detection biomarkers. Brain-derived EVs in body fluids contain disease-related biomolecules can be used as early diagnostic biomarkers for NDDs. In addition, as one of the subpopulations of EVs, exosomes, especially stem cell-derived exosomes, have great potential in the treatment of NDDs. The ability to cross the BBB, together with the feasibility of versatile functionalization of EV for NDDs pathogen targeting facilitate EVs a potential tool for targeted drug delivery systems for NDDs. In this review, the important role of EVs in the diagnosis and treatment of NDDs and the current research progress will be discussed.