FIGURE 3.

Highlights of the maturation of cardiac energy metabolism. During the cardiac perinatal development, the heart adapts to the increased workload by increasing its size by hyperplasia and then by hypertrophy. Over this period, the heart undergoes profound metabolic upheavals, notably marked by a significant increase in its oxidative capacities. This leads to the progressive establishment of a metabolism that is overwhelmingly oxidative and based on the use of fatty acids. Then, efficient energy transfer systems emerge, correlating with the appearance of an intracellular architecture displaying an increasingly complex level of organization. Pictures A and B are electron micrographs of 3-day-old cardiomyocytes of papillary muscle while pictures C and D are electron micrographs of 63-day-old cardiomyocytes of papillary muscle (adapted from Piquereau et al., 2010 with permission).