AKT1 and obesity due to melanocortin 4 receptor deficiency: Experimental limitations: Although our study provided a likely causal relationshipamong cardiac mechanical function, intracellular Ca2+homeostasis, NADPH oxidase, O2− accumulation,Akt/eNOS and stress signaling activation between aging and obesity, caution shouldbe taken for the interpretation of the precise interaction between aging and obesityin cardiac dysfunction in the human setting.