Regarding the mechanism of action of MSC in treating ARDS, MSC, and their extracellular vesicles exert potent antimicrobial effects through direct and indirect mechanisms.[52,53] Second, MSC can restore the permeability of the alveolar–capillary barrier, stabilizing lung endothelial barrier function through the secretion of hepatocyte growth factor[54] in extracellular vesicles. The gene discussed is HGF; the disease is acute respiratory distress syndrome.