Interestingly, in various cells, including renal fibroblasts and MC, activins have also been shown to be critical for the profibrotic response to TGFβ1 [14,19,20,21], a cytokine central to the pathogenesis of DKD [22], although the mechanism underlying this has not been defined as of yet. This evidence concerns the gene TGFB1 and diabetic kidney disease.