Cao et al. (2019) showed that MSC-EVs can significantly reduce colitis caused by DSS in mice by inducing colonic macrophage polarization in the immunosuppressive M2 phenotype, and they observed more IL-10-producing M2 macrophages in MSC-EV-treated mice, which was associated with weight loss, intestinal epithelial cell damage and increased colon length. Yang et al. (2015) suggested that MSC-EV effects on the phenotype and function of macrophages occur by the regulating the damaged intestinal antioxidant/oxidant balance. The gene discussed is IL10; the disease is colitis.