TGFB1 and diabetic kidney disease: It is known that high blood glucose promotes the accumulation of extracellular matrix (ECM) [30] and upregulates the expression of DKK1, the Kremen-2 receptor, transforming growth factor-beta (TGF-β), and fibrotic factors in mesangial cells [31], which ultimately escalates to damage to the glomerular filtration barrier to cause DKD.