SMAD3 and diabetes mellitus: demonstrated in vivo and in vitro that exosomes from macrophages treated with high glucose activate glomerular mesangial cells through the TGF-β1/Smad3 pathway (17).Another important study revealed that mesenchymal stem cell-derived exosomes ameliorated diabetes-induced myocardial injury and fibrosis by inhibiting TGF-β1/Smad2 signaling pathway (18).In addition, Han et al.