Abstract

Brain-derived exosomes (BDEs) are extracellular nanovesicles released by all central nervous system cell lineages and contain cargo from the cells that produced them. In physiological and pathological conditions, they are becoming more well-known as critical mediators of communication and waste management between neurons, glial cells, and connective tissue in the brain. It may provide a mechanistic view of the disease phenotype, useful for diagnosis and therapeutic intervention. We emphasize the importance of exosomes as a pathogenic agent and a disease biomarker in Alzheimer's disease (AD), Parkinson's disease (PD), Multiple Sclerosis (MS), and Glioblastoma. It is because exosomes have the ability to cross the blood–brain barrier, our understanding of these unique nanovesicles may provide not only answers about the neurodegenerative diseases but also ideal methods for developing these vesicles as drug delivery vehicles or tools to monitor brain diseases in a non-invasive manner. This review will discuss exosomes' physicochemical properties, extraction, and diagnosis functions in the brain and relate new findings to current evidence of exosome nanoparticles in brain disorders. © 2022 Elsevier B.V.