Autophagy represents an evolutionarily conserved catabolic mechanism that promotes cell survival by releasing energy substrates via degradation of cellular constituents and by eliminating defective organelles under conditions of stress, such as starvation and hypoxia. The link between enhanced autophagy and nutrient deprivation has been well established. For example, chronic myocardial ischemia, a condition of insufficient oxygen and nutrition, activates autophagy to degrade and recycle damaged cellular structures, thereby ameliorating cardiomyocyte injury.