IGF1 and type 2 diabetes mellitus: Research has shown that exosomal miR-320 released by central muscle cells of T2DM mice can be transferred to mouse cardiac endothelial cells, impairing the function of adjacent cardiac endothelial cells by down-regulating the expression of insulin-like growth factor 1 (IGF-1), heat shock protein 20 (HSP-20), and E26 transcription factor 2 (E-twenty-six 2).