Scientists prove human heart can regenerate cells

By Kylie MacLellan

LONDON (Reuters) - Scientists said on Thursday they had shown the human body regenerates heart cells at a rate of about one percent a year, a discovery that could one day reduce the need for transplants.

The study of 50 volunteers, using a dating method that detects traces of a carbon isotope left by Cold War nuclear bomb tests, raises the prospect of artificially stimulating the renewal process some day, they reported in the journal Science.

"It would be a way to try and help the heart to some self-help rather than transplanting new cells," Jonas Frisen of Sweden's Karolinska Institute said in a telephone interview.

"Taking advantage of the heart's own capacity to generate new cells either using pharmaceutical compounds or, if it is possible, by exercise or any other environmental factor."

Heart cells are unusual in that they stop dividing early in life. Doctors knew there were master cells called stem cells in the heart, but heart muscle usually simply forms scar tissue after damage and never fully regenerates.

In their four-year study, Frisen and colleagues employed an ingenious method to find out whether there is any regeneration at all.

"The DNA of all plant and animal cells incorporated high concentrations of carbon-14 released into the atmosphere by above-ground nuclear testing during the Cold War, and this unfortunate episode provides a unique opportunity to test cell population dynamics in human tissues," Charles Murry of the University of Washington and Richard Lee of Harvard Medical School wrote in a commentary.

Carbon-14 dating showed that overall, the hearts of their 50 volunteers were "younger" than the patients' ages.