Gene expression of the myofibroblast marker α-smooth muscle actin (Acta2) and matrix molecules collagen 1 (Col1a1), collagen IV (Col4a3) and fibronectin (Fn1) were all increased 2- to 3- fold in kidneys at week 12 of diabetes (Figure 7D–G). This evidence concerns the gene COL4A3 and diabetes mellitus.