In this context, the exact source of these cells is unclear and controversial and only in few nephropathies such as diabetic nephropathy, the development of renal fibrosis is more clearly associated with intrarenal TGF-β1 induced transition of secondary epithelial cells towards myofibroblastic cells: the so-called Type II EMT [13–15]. Here, TGFB1 is linked to diabetic kidney disease.