REN and diabetes mellitus: Though the pathogenesis and pathophysiology of DCM is multifactorial and poorly understood, current evidence suggests that diabetes affects cardiac remodeling through a variety of mechanisms (Figure 1), including over-activation of the renin-angiotensin system, insulin resistance, metabolic disturbances (hyperglycemia, hyperinsulinemia and hyperlipidemia), fibrosis and impairment of calcium homeostasis [28,29,30].