Characterization of Mesenchymal Stromal Cells after Serum Starvation for Extracellular Vesicle Production

Featured Application: Mesenchymal stromal cell derived-extracellular vesicles (MSC-EVs) are considered an alter-native approach to cell therapies. They are derived from in vitro starved cells, and we demon-strated that they maintain their functional properties. For this reason, we support the idea that MSCs after starvation, otherwise discarded, could be collected and used as therapeutic agents. It has been demonstrated that mesenchymal stromal cells (MSCs) act by releasing bioactive molecules, among these are extracellular vesicles (EVs). The MSC-EVs are considered a convenient alternative to cell therapy, showing several functional characteristics of their origin cells. EVs can be collected from conditioned in vitro cultured MSCs. Different processes have been developed to induce in vitro EV release, and these approaches have been demonstrated to also influence MSC potentialities. This study aimed to investigate the effect of serum starvation on MSC characteristics. The morphology, phenotype, differentiation capacity, immunomodulatory ability, and metabolic state were maintained by MSCs cultured under starvation. To evaluate basic ultrastructural characteristics of cells and EVs, Transmission Electron Microscopy (TEM) analysis was performed on MSCs after 12, 24, and 48 h starvation, demonstrating that 24 h starvation was the best time for MSC structure preservation. Further studies are needed to support the hypothesis that MSCs after starvation could still be considered as therapeutic agents.