Dr. Bernhard Kuhn of the Department of Cardiology at Boston Children's Hospital said the findings refuted the long-held belief that the human heart grows after birth exclusively by enlargement of existing cells, and raises the possibility that scientists could stimulate production of new cells to repair injured hearts.
Since 2009, Kuhn and his team looked at specimens from healthy human hearts, ranging in age from 0-59, and documented the cells in these hearts were still dividing after birth, significantly expanding the heart cell population.
The study, published in the Proceedings of the National Academy of Sciences, found cells regenerated at their highest rates during infancy, but while regeneration declined after infancy, it rose during the adolescent growth spurt, and continued up until around age 20.
"For more than 100 years, people have been debating whether human heart muscle cells are generated after birth or whether they simply grow larger," Kuhn said.
For many years, the accepted belief in the scientific community was that human hearts grow after birth only because cells grow larger, Kuhn added.