Cardiomyocytes renew at a rate of 1% annually at age 25, decreasing to 0.45% by age 75, with fewer than 50% replaced over a lifetime.
Adult human cardiomyocytes have the capacity to renew throughout life, providing a biological rationale for developing regenerative therapies for cardiac pathologies.
It has been difficult to establish whether we are limited to the heart muscle cells we are born with or if cardiomyocytes are generated also later in life. We have taken advantage of the integration of carbon-14, generated by nuclear bomb tests during the Cold War, into DNA to establish the age of cardiomyocytes in humans. We report that cardiomyocytes renew, with a gradual decrease from 1% turning over annually at the age of 25 to 0.45% at the age of 75. Fewer than 50% of cardiomyocytes are exchanged during a normal life span. The capacity to generate cardiomyocytes in the adult human heart suggests that it may be rational to work toward the development of therapeutic strategies aimed at stimulating this process in cardiac pathologies.
Bergmann et al. (2009) studied this question. Cardiomyocytes renew at a rate of 1% annually at age 25, decreasing to 0.45% by age 75, with fewer than 50% replaced over a lifetime.