INS and diabetes mellitus: Animal studies showed that MSCs transplantation increased the levels of insulin and C-peptide in type 1 diabetes mellitus and T2DM by promoting the replication of residual β-cells, improving the autophagy function of islets, promoting the phenotypic dedifferentiation of islet β-cells and the polarization repair of macrophages in the local microenvironment of islets [26, 27].