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The University of Pittsburgh Medical Center on Thursday launched the nation's first clinical trial to test the safety and gauge the promise of using injections of a patient's own stem cells to pump life into a dying heart.

Cardiologists say the trial marks an important step in the push to develop stem cell therapies to treat the estimated 5 million Americans who live with congestive heart failure, for which the only cure is heart transplants.

It also should help physicians solve the mystery of how exactly adult stem cells act when they are introduced to a damaged heart, experts say.

"There are millions of people in the United States who have chronic heart failure, and there's no treatment for them," said Dr. Darwin Prockop, who heads the Center for Gene Therapy at Tulane University Health Sciences Center in New Orleans and isn't part of the UPMC trial.

Stem cell therapies are being used in other parts of world with encouraging results.

"Most reports from 10 centers around the world are saying that the injection of stem cells can help," Prockop said. "But we know very little about how the cells are working, so the therapy is still a risk."

The stem cell trial to address this question of how adult stem cells might act to repair the heart is being led by Dr. Amit Patel, who runs UPMC's Center for Cardiac Cell Therapy, and his colleague Dr. Robert Kormos, who heads the center's artificial heart program and serves as medical director of the University of Pittsburgh's McGowan Institute for Regenerative Medicine.

Last April, Patel and Kormos reported promising results from an early trial looking at the impact of stem cell therapy on 20 heart patients who also underwent coronary bypass surgeries. In late January, they presented related data showing that 15 patients who had received injections of stem cells directly into the heart pumped blood much better than their counterparts who did not receive these cells.

Both of these studies were conducted at medical centers in South America.

Since then, the U.S. Food and Drug Administration has cleared the way for similar studies at three sites across the U.S., including UPMC, St. Elizabeth's Medical Center in Boston and Texas Heart Institute in Houston, Patel said.

The Pittsburgh trial will be the only one to inject stem cells directly into the heart. The other studies will deliver cells through a catheter leading into the coronary arteries of patients with angina, or chest pain, Patel said.

The trial here will enroll five to 10 patients awaiting heart transplants because of severe congestive heart failure, which occurs when the heart loses its pumping power, causing the potentially lethal build-up of fluid in the lungs and other organs. About 550,000 new cases of this debilitating condition are diagnosed every year, according to the American Heart Association.

In addition to stem-cell injections, patients in the trial will receive left ventricular assist devices -- battery-powered mechanical heart pumps -- to buy time until donor hearts become available for transplant. Doctors will monitor these patients regularly to see whether there is any improvement in blood-pumping efficiency and other cardiac functions.

"It's kind of the best of both worlds," Patel said. "In these super-sick people, if the cells do something very positive, then they can opt not to undergo transplant. If that doesn't happen, they have the ventricular assist device as a bridge to transplant. There's no downside."

The stem cell injections will take place when the ventricular assist devices are implanted.

Like unmolded clay, adult stem cells are master cells with the potential to morph into specific cell types when exposed to the right biochemical signals. The body deploys stem cells where needed to repair damaged or dead cells.

The stem cells used in this study will be harvested from a patient's own hip bone marrow and then injected into 25 to 30 diseased spots on half of the heart about three hours after the assist device is connected. Depending on body weight, each patient will receive from 25 million to 45 million stem cells.

The other half of the heart will be injected with plasma, Patel said.

That way, after a transplant, pathologists can compare tissue samples from areas of the diseased heart that did and did not receive stem cells. These samples also would be compared to those taken during a biopsy done at the time of surgery.

This will help Patel and his colleagues determine how stem cells might work to fix the heart.

One theory is that stem cells become transformed into new heart muscle tissue or blood tissue; another possibility is that they fuse with a patient's own cells to help them work better. Alternatively, the stem cells could act like homing signals to attract other repair substances to the heart, which is the most likely scenario, Patel said.

"The heart consists of trillions of cells, and we're only injecting millions of cells, yet we're seeing improvements at medical centers across the world," Patel said. "It has to be something more than just these cells themselves."

If the trial is successful, Patel and his colleagues will test giving stem cell injections in conjunction with coronary bypass surgery. Stem cell therapy as a minimally invasive procedure could be just a year or two away, he said. This already is becoming a reality in Thailand and other countries in Asia and Europe, where many Americans are traveling for treatment, Patel said.

Stem cell therapy is coming too late to help Bill McGeary, 40, of Avonmore, Westmoreland County, who suffered heart failure in November 2003 due to complications from diabetes and drug abuse. McGeary is awaiting a heart transplant, but meantime, he is hooked up to a left ventricular assist device that enables his deteriorating heart to pump. The former security guard is hopeful the treatment may save other people from the pain he has suffered.

"If it works, it's going to help a lot of people like me, and maybe they won't have to go through transplant," McGeary said. "If that happens, it would be great."

In addition to showing stem cell therapy is safe and feasible, researchers also must show that it improves quality of life, said Dr. Valentin Fuster, past president of the American Heart Association and director of the Cardiovascular Institute at Mt. Sinai Medical Center in New York. Congestive heart patients shouldn't expect miracles.

"I think it's an interesting study on a new concept, but it's a long road," Fuster said. "The stem cells may change the function of the muscles in the heart, but the question is going to be to what degree that impacts the patient."

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