Fig. 1.

Hypothetical scenario of mitochondrial quality control failure, organellar dysfunction, and triggering of mitochondrion-mediated apoptosis during cardiac aging. The aged myocardium is characterized by the presence of enlarged mitochondria with aberrant morphology, reduced bioenergetic efficiency, and increased reactive oxygen species (ROS) production. The formation of giant mitochondria may be the consequence of a shift of mitochondrial dynamics toward fusion. This adaptation could allow diluting mitochondrial abnormalities along the network. Enlarged mitochondria are, however, less susceptible to mitophagic degradation because of their larger dimensions. The accumulation of lipofuscin within lysosomes may further impair the efficiency of mitochondrial quality control. Excessive oxidant production eventually triggers apoptosis. The artwork is by Francesco Antognarelli.