NPHS1 and diabetic kidney disease: Further, the blood pressure and the expression of proteins involved in glomerular filtration barrier (nephrin), tubular injury (KIM-1), and fibrosis, (connective tissue growth factor (CTGF), transforming growth factor-β1 (TGF-β1), and alpha-smooth muscle actin (α-SMA)) were assessed as markers of progression of diabetic nephropathy.