Genetic Switch Fixes Damaged Hearts

Researchers at Columbia University Medical Center have discovered a genetic switch that allows mice to repair heart muscles damaged by heart attacks, and the research may be applicable to humans as well.

Normally, heart cells in mice, and in humans, stop regenerating after birth. If the heart is damaged by a heart attack, it cannot create new cells to repair the damage and hearts become less efficient at pumping blood. The team at Columbia University Medical Center in New York found that by genetically manipulating a gene associated with cell growth--called cyclin A2--adult mice were able to make new cells to replace those damaged in a heart attack.

The researchers engineered mice that continue to express cyclin A2 throughout their lives (normally it is only expressed in embryos). Later, they induced heart attacks in the mice. At three months, the mice whose cyclin A2 genes had been switched on had 77 percent better heart function than the other mice.

Most of the mice that did not have cyclin A2 activated progressed to heart failure and died, while none of the mice that expressed cyclin A2 died.

The research needs to be tested in larger mammals and eventually humans before any therapies useful to us will be available, but this is great progress and hopeful news, especially for those of us with a family history of heart attacks.