Extracellular Vesicle Heterogeneity and Its Impact for Regenerative Medicine Applications

vesicles (EVs) are cell-derived membrane-enclosed particles that are involved in phys-iologic and pathologic processes. EVs are increasingly being studied for therapeutic applications in the field of regenerative medicine. Therapeutic application of stem cell-derived EVs has shown great potential to stimulate tissue repair. However, the exact mechanisms through which they induce this effect have not been fully clarified. This may to a large extent be attributed to a lack of knowledge on EV heterogeneity. Recent studies suggest that EVs represent a heterogeneous population of vesicles with distinct functions. The het-erogeneity of EVs can be attributed to differences in their biogenesis, and as such, they can be classified into distinct populations that can then be further subcate-gorized into various subpopulations. A better under-standing of EV heterogeneity is crucial for elucidating their mechanisms of action in tissue regeneration. This review provides an overview of the latest insights on EV heterogeneity related to tissue repair, including the different characteristics that contribute to such hetero-geneity and the functional differences among EV sub-types. It also sheds light on the challenges that hinder clinical translation of EVs. Additionally, innovative EV isolation techniques for studying EV heterogeneity are discussed. Improved knowledge of active EV subtypes would promote the development of tailored EV thera-pies and aid researchers in the translation of EV-based therapeutics to the clinic. Significance Statement--Within this review we discuss the differences in regenerative properties of extracellular vesicle (EV) subpopulations and implica-tions of EV heterogeneity for development of EV-based therapeutics. We aim to provide new insights into which aspects are leading to heterogeneity in EV prep-arations and stress the importance of EV heterogene-ity studies for clinical applications.