The researchers, whose previous studies on rabbits already have shown that gene therapy can prevent such damage, believe that one day gene therapy could be used to treat heart damage, and in people, not just animals. In people with congestive heart failure, the heart muscle cannot stretch and contract normally, usually because of coronary artery disease or a heart attack. Roughly 550,000 new cases of congestive heart failure are diagnosed every year in the United States, and nearly 47,000 people die each year from the condition. Between 1979 and 1998, the number of deaths from this disease increased by 135 percent. In a healthy heart, this enzyme helps restore normal muscular contractions after a release of adrenaline kicks the heart into high gear.
Adrenaline speeds up the heart by binding to beta-adrenergic receptors on heart cells.
But continued fast pounding leads to heart failure. Koch, an associate professor of experimental surgery, had found that failing heart tissue contains levels of BARK three times higher than normal. But because no chemical inhibitors exist to do that, Koch says, the researchers looked to a genetic solution to boost the heart's ability to pump blood. They then directed it into the coronary arteries of the left ventricles of rabbits that had experienced a heart attack. Details appear in today's issue of the journal Circulation .