Evidence for Cardiomyocyte Renewal in Humans

TLDR

It has been unclear whether humans are limited to the cardiomyocytes they are born with or can generate new ones later in life. The study used the incorporation of Cold‑War era carbon‑14 into DNA to date human cardiomyocytes. Cardiomyocytes renew at a declining rate—from about 1 % per year at age 25 to 0.45 % at age 75—with less than half of cells replaced over a lifetime, indicating that adult human hearts retain a capacity for regeneration that could be therapeutically harnessed.

Abstract

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.