Researchers from University of Texas Southwestern Medical Center in studies with mice found that microRNAs - tiny strands that regulate gene expression - contribute to the heart's ability to regenerate up to one week after birth and soon thereafter the heart loses the ability to regenerate.
"For the first time since we began studying how cells respond to a heart attack, we now believe it is possible to activate a programme of endogenous regeneration," said Dr Hesham Sadek, assistant professor of internal medicine in the division of cardiology, and the senior author of a study in the Proceedings of the National Academy of Sciences.
In 2011, a team led by Dr Eric Olson, chairman of molecular biology, and Sadek demonstrated that within three weeks of removing 15 per cent of the newborn mouse heart, the organ was able to completely grow back the lost tissue, and as a result looked and functioned normally.
In the latest investigation, researchers found that hearts of young rodents mounted a robust regenerative response following myocardial infarction, but this restorative activity only occurs during the first week of life.
They then discovered that a microRNA called miR-15 disables the regenerative capacity after one week, but when miR-15 is blocked, the regenerative process can be sustained much longer.
"We're encouraged by this initial finding because it provides us with a therapeutic opportunity to manipulate the heart's regenerative potential," said Olson, a co-corresponding author of the study.
"This may well be the beginning of a new era in heart regeneration biology. Our research provides hope that reawakening the regenerative capacity of adult mammalian hearts is within reach," Sadek said.