Heart cells renew themselves throughout life: study
Last Updated: Friday, April 3, 2009 | 2:20 PM ET
CBC News
Humans regenerate heart cells throughout their lives, say scientists who found the rate of renewal slows into adulthood.
The finding published in Friday's issue of the journal Science could open the door to a new way of treating heart attacks.
In the study, researchers in Sweden and the U.S. said the beating cells in the heart, called cardiomyocytes, are renewed.
Until now, scientists didn't know whether we were born with a set number of cardiomyocytes or if renewal was possible later in life.
“DNA of myocardial cells is synthesized many years after birth, indicating that cells in the human heart do, in fact, renew into adulthood,” study author Bruce Buchholz of Lawrence Livermore National Laboratory in California said in a release.
The team looked for an answer by using carbon-14 dating to estimate the lifespan of heart cells based on when DNA synthesis occurred.
The scientists were able to use carbon-14 since levels of the isotope rose in the 1950s when above-ground tests of nuclear bombs were done. Since then, levels of carbon-14 have decreased in cells.
"We report that cardiomyocytes renew, with a gradual decrease from one per cent turning over annually at the age of 25 to 0.45 per cent at the age of 75," Jonas Frisen, a professor of stem cell research at the Karolinska Institute in Stockholm, and his colleagues wrote.
The findings mean that even among people who live a very long life, they won't exchange more than half of their cardiomyocytes.
If scientists can understand how new cardiomyocytes are generated, it could be possible to develop new drugs that stimulate regeneration to restore damaged hearts, such as after a heart attack, the researchers said.
Any potential regeneration therapies arising from the research would need to be tested to ensure they are safe and effective.
