Newborn heart can heal itself.

• Position: Cardiothoracics

In a promising science-fiction-meets-real-world juxtaposition, researchers have discovered that a newborn heart can heal itself completely--a significant portion of the heart removed during the first week after birth grew back wholly and correctly as if nothing had happened.

"This is an important step in our search for a cure for heart disease, the number one killer in the developed world," expounds Hesham Sadek, senior author of the study published in Science. "We found that the heart of newborn mammals can fix itself; it just forgets how as it gets older. The challenge now is to find a way to remind the adult heart how to fix itself again."

Previous research has demonstrated that the lower organisms--like some fish and amphibians--that can regrow fins and tails also can regrow portions of their hearts after injury. "In contrast, the hearts of adult mammals lack the ability to regrow lost or damaged tissue and, as a result, when the heart is injured, for example after a heart attack, it gets weaker, which eventually leads to heart failure," Sadek explains.

Within three weeks of removing 15% of a mouse's newborn heart, it was able to grow back the lost tissue completely and, as a result...