Regenerating cells after a heart attack.

• Position: Cardiology - Brief article

A molecular mechanism needed to unleash the heart's ability to regenerate has been pinpointed. This is a critical step toward developing eventual therapies for damage suffered following a heart attack.

MicroRNAs--tiny strands that regulate gene expression--contribute to the heart's ability to regenerate up to one week after birth. Soon thereafter, however, the heart loses the ability to regenerate. By determining the fundamental mechanisms that control the heart's natural regenerative on-off switch, researchers have begun to understand better the No. 1 hurdle in cardiovascular research--the inability of the heart to regenerate following injury.

"For the first time since we began studying how cells respond to a heart attack, we now believe it is possible to activate a program of endogenous regeneration," suggests internist Hesham Sadek, senior author of a study published in the National Academy of Sciences.

"It is a fresh perspective on an age-old problem," relates Eric Olson, director of Texas' Center for Basic...