Diabetes further exacerbated myocardial IR-induced left ventricular dysfunction and infarct size, and the depression of cardiac microcirculation through the enhancement of leukocyte infiltration and NADPH oxidase p22 and p67 derived ROS and oxidative stress and a reduction in BAG3, Bcl-2 and Nrf-2/HO-1 protective signaling in the heart. The gene discussed is BAG3; the disease is diabetes mellitus.