Repairing Damaged Heart Muscle

After a heart attack, the best one can generally hope for is that the area of damage becomes scar tissue that is sufficiently strong to withstand the high blood pressures generated in the heart. That’s because in adult mammals, cardiac muscle does not rebuild or repair itself after an injury. And yet, adult frogs, newts, and some fish still do have the ability to rebuild functional heart tissue after injury – what’s the difference?

One hypothesis is that the general ability of heart muscle to regenerate in essentially all embryos is switched off shortly after birth in higher mammals. In support of this hypothesis, researchers have now shown that mouse hearts do undergo structural and functional regeneration, but only if the damage occurs within the first week after birth. These findings raise the possibility that if we could understand the process of heart muscle regeneration in a newborn mouse, we might be able to induce the process again in adult mammals if necessary. Ultimately this could lead to new approaches for the treatment of victims of heart attacks.