Stem cell extracellular vesicles for neuropsychiatric disorders and translation.

Neuropsychiatric disorders represent a major global health challenge due to their high prevalence, chronic disability, and substantial socioeconomic burden. Although stem cell-based therapies offer regenerative potential, their clinical application is limited by poor post-transplantation survival, restricted targeted integration, and potential tumorigenicity. Stem cell-derived extracellular vesicles (SC-EVs), particularly exosomes, have emerged as a promising cell-free therapeutic approach. These vesicles can cross the blood-brain barrier (BBB) and exhibit high biocompatibility and low immunogenicity. This review summarizes the cellular origins and biogenesis of SC-EVs and evaluates current preclinical and clinical evidence supporting their therapeutic potential. Particular attention is given to acute ischemic stroke and progressive neurodegenerative disorders, including Alzheimer's disease and Parkinson's disease. In addition, the molecular mechanisms underlying their neuroprotective and regenerative effects are discussed, with a focus on modulating neuroinflammation, promoting neurogenesis, and enhancing synaptic plasticity. Finally, key advances and major challenges in the clinical translation of SC-EVs are outlined. Integrating current evidence, this review provides a framework and practical perspective for the continued development of SC-EV-based therapies for complex neurological disorders.