Enhancing the Therapeutic Potential of Human Umbilical Cord Mesenchymal Stem Cells for Osteoarthritis: The Role of Platelet-Rich Plasma and Extracellular Vesicles.

Osteoarthritis (OA) is a chronic degenerative joint disease. Our previous study demonstrated that extracellular vesicles (EVs) secreted by human umbilical cord mesenchymal stem cells (HUCMSCs), which play a crucial role in regenerative medicine, have therapeutic effects on OA. Additionally, platelet-rich plasma (PRP) has been widely used in musculoskeletal diseases as it promotes wound healing, angiogenesis, and tissue remodeling; however, its efficacy as a stand-alone therapy remains controversial. Therefore, we investigated the therapeutic effects of combining stem cell-derived EVs with PRP in an OA model. HUCMSC-derived EVs treated with PRP were used as the experimental group, whereas HUCMSC-derived EVs cultured with serum-free (SF) or exosome-depleted fetal bovine serum (exo(-)FBS) and PRP served as controls. PRP-treated HUCMSCs maintained their surface antigen characteristics and potential to differentiate into adipocytes, osteoblasts, and chondrocytes. In the OA model, mice treated with HUCMSCs + 5% PRP-derived EVs showed significantly improved motor function compared to controls and were comparable to those treated with HUCMSCs +SF and +exo(-)FBS-derived EVs. Additionally, increased type II collagen and aggrecan and decreased IL-1β expression were observed in cartilage transplanted with various EVs. In conclusion, PRP enhances HUCMSC differentiation, whereas treatment with EVs improves OA outcomes, providing a promising strategy for future clinical applications.