MMP9 and familial dilated cardiomyopathy: In addition to cardiomyocyte apoptosis, intensive cardiac fibrosis is another crucial characteristic of DCM.41, 42 Excess production and deposition of ECM, principally collagen I and III, can alter the structure of the heart and lead to severe cardiac dysfunction.10, 42 And HG stimulates MMP‐2 and MMP‐9 expression in diabetic hearts which accelerates tissue remodelling and cardiac fibrosis.