GENE THERAPY MAY AID HEART BYPASSES.

Byline: Daniel Q. Haney Associated Press

Scientists tinkering with gene therapy think they have found a way to make bad hearts grow their own bypasses.

The idea is to inject extra genes directly into the heart that will trigger it to sprout new blood vessels within two to three weeks. If all goes well, these will work at least as well as the ones surgeons stitch into place during coronary bypass surgery.

So far, doctors from Boston have tried the gene therapy on people with dangerously clogged arteries in the legs, where it seems to have spared some from threatened amputations.

For several years, scientists have talked about manipulating genes to cure a variety of human ills. But until now, there has been little firm evidence that it will do any good.

``This is the first time that any gene therapy has been shown to be clinically successful,'' said Dr. Jeffrey Isner of St. Elizabeth's Medical Center in Boston.

Reports by Isner and another team working on a different gene therapy approach were presented Sunday at a meeting of the American Heart Association. If their promising but preliminary findings stand up to more rigorous testing, gene therapy may someday prove be an important way to control heart disease, the nation's biggest killer.

``This is opening a door to genetic therapy in cardiovascular disease,'' said Dr. Valentin Fuster of Mount Sinai Medical Center in New York City, incoming president of the heart association.

So far, 20 patients with severely clogged arteries in their legs have received injections of laboratory-made versions of the human gene that makes vascular endothelial growth factor, a protein that prompts blood vessel development during growth in the womb.

Of these, Isner said 16 have responded by growing new blood vessels that carry blood around the blockages.

Several of the patients have been spared the need for leg amputations. Others have been freed of constant pain.

Isner said MRI scans and X-rays show improved circulation, and the blood pressure in the patients' legs has increased - something that never happens by itself in such cases.

He said he has asked the federal Food and Drug Administration for permission to start the therapy on patients with blockages in their hearts, which biologically are virtually identical to clogged leg arteries. He hopes to begin those experiments by early next year.

Drs. Michael Mann and Victor J. Dzau of Brigham and Women's Hospital in Boston are using gene therapy to try to make traditional bypass surgery work better.

Over time, about half of the blood vessels used to reroute blood in the heart or the legs become clogged. Their goal is to alter the grafts genetically so this does not happen.