Effect of extracellular vesicles derived from hypoxia-preconditioned human mesenchymal stem cells on osteoblastogenesis and adipogenesis in vitro

Objectives: mesenchymal stem cells (MSC) are characterized by their anti-inflammatory, immunosuppressive activity, and their ability to differentiate. This makes them an interesting therapeutic tool in cell therapy and regenerative medicine. In part, the therapeutic effect of MSC is mediated by the secretion of extracellular vesicles (EV). The preconditioning of MSC in hypoxia can enhance the regenerative capacity of the secreted EV. In this context, the aim of the study was to evaluate whether EV derived from human MSC cultured in normoxic and hypoxic conditions affect the osteoblastogenesis and adipogenesis of MSC.Material and methods: EV were isolated from MSC maintained for 48 hours in normoxic or hypoxic conditions (3 % O2) using ultrafiltration and size exclusion chromatography. The EV were characterized by Western blot, electron microscopy, and nanoparticle tracking analysis. In MSC cultures, the effect of the EV on viability was evaluated using an MTT assay, migration was assessed with the Oris assay while differentiation into osteoblasts and adipocytes was also studied.Results: the EV increased viability and migration, but no differences were seen between those derived from normoxic and hypoxic culture conditions. The EV, mainly those derived from hypoxia, increased both mineralization, and the expression of osteoblastic genes. However, they did not affect adipogenesis significantly.Conclusions: the EV derived from MSC in hypoxia do not affect adipogenesis but have a greater ability to induce osteo-blastogenesis. Therefore, they could potentially be used in bone regeneration therapies and treatments for bone conditions like osteoporosis.