Secretome - the role of extracellular vesicles in the pathogenesis and therapy of neurodegenerative diseases.

Purpose: Extracellular vesicles are the subject of many studies in various medical specialties. Their role in neurodegenerative diseases is increasing and they worth introducing in more detail. Methods: This review was performed following an electronic search of the database PubMed/Medline and Web of Science for English-language articles between 2010 and 2024 in the fields of medicine, molecular biology, and biochemistry. Keywords searches included combinations of the following terms: "extracellular vesicles" OR "exosomes" AND "neurodeg*" AND "microRNA" OR "miRNA" AND "AD" OR "PD" OR "ALS" OR "HD". Articles had to be original work or reviews. Results: The classification of extracellular vesicles is based on their size or origin. Their content is of key importance in communication between cells and can be treated as a physiological determinant of the normal or pathological condition of a body. The cargo transported in the extracellular space and over longer distances in various body fluids is diversified and may be nucleic acids (DNA, RNA, miRNA) as well as proteins and lipids, and, in the case of apoptotic bodies also a cell's organelles. Exosomes are the most thoroughly studied extracellular vesicles and the most often considered for therapeutic applications. Vesicles carrying biological substances in the body perform three basic functions: participation in a pathological mechanism, a biomarker role that also has diagnostic and prognostic functions, and a role in therapeutic activities. In the case of neurodegenerative diseases, it appears that extracellular vesicles can transport misfolded proteins, initiating pathological processes in previously normal cells. Conclusions: The transport of various substances enclosed in vesicles seems to be very promising in therapeutic prospects in various diseases, and the possibility of their crossing the blood-brain barrier particularly indicates diseases of the central nervous system. Despite many years of research on extracellular vesicles in the context of neurodegenerative diseases, their practical use is currently limited to studies on animal and cellular models, and their practical application in clinical trials in neurodegenerative diseases is to date extremely rare.