CHICAGO (AP) - Some people virtually housebound by congestive heart failure dramatically improve and even return to work after doctors insert new cells into their severely damaged pumping muscle, according to a report Monday.
The experiment is the latest attempt at cell therapy, an approach still early in development that shows enticing hints it can restore life to stunned and scarred areas of weakly beating hearts.
Several teams around the world are using a variety of approaches, involving either primitive bone marrow cells or immature skeletal muscle cells to refurbish damaged heart muscle.
While it is still too soon to say how well the approach works - or even whether it does at all - doctors say they have been impressed with apparent reversals of severe heart failure after the experiments.
Dr. Emerson Perin of the Texas Heart Institute, who presented data Monday, said he was amazed when one of his patient who had not been able to leave his home told him he had just climbed eight flights of stairs. "I told him to take it easy!" Perin said.
Perin's results were among several studies on new approaches to heart failure discussed at a meeting in Chicago of the American College of Cardiology. Doctors also reported improvement with new drugs and devices that resynchronize the failing heart.
Heart failure occurs when the heart cannot contract powerfully enough to force sufficient blood through the circulatory system. It afflicts about 5 million Americans and is growing more common as people live longer and survive heart attacks.
Perin's team harvested primitive cells, called stem cells, from the patients' own marrow. They chose cells that seemed most likely to develop into blood vessels and injected 30 million copies into the damaged parts of their hearts.
Ordinarily, the heart pushes out more than half of its blood with each beat. Perin's patients had such bad heart failure that their hearts pumped just 20 percent. After the procedure, this increased to 29 percent.
Several of the patients, including the stair-climber, soon felt better. One man returned to work. Another began going to the beach and, showing off a deep tan, told his doctor that he could spend an hour and a half at a time in the water.
Still, Perin cautioned that a placebo effect could account for the apparent benefit. Patients may feel better because they are convinced the treatment should help them.
Just why the approach might work is unclear, although Perin speculated that the immature cells produce hormones and chemicals that promote blood vessel growth, reawakening dormant heart muscle.
"We believe it's very promising, but it's also very early," said Dr. James Willerson, another Texas Heart researcher. "These were all patients with very extensive coronary artery disease, prior heart attacks, severe heart failure, and they were desperate."
Several other teams around the world are working on similar approaches. Dr. Tomasz Siminiak of District Hospital in Poznan, Poland, updated researchers Monday on 10 patients who received immature muscle cells into their poorly working hearts during bypass surgery. After one year, their pumping power increased between 5 and 20 percentage points, although it was unclear whether the operation or the new cells triggered the improvement.
Other researchers are injecting genes, rather than cells, into damaged hearts. "Eventually I think we will combine cells and genes so they can work together," said Dr. Jens Kastrup, a gene therapy researcher at Copenhagen University Hospital.
The Texas Heart doctors are considering this step. Willerson said they hope to engineer stem cells that will carry in extra genes to promote blood vessel growth, regulate calcium transport and minimize oxygen damage.
Among other heart failure studies presented Tuesday:
-Dr. Bertram Pitt of the University of Michigan reported that a newly approved drug called eplerenone reduced deaths by 15 percent when given to heart failure patients who were already getting all the other standard drugs. The medicine has fewer side effects than a closely related older drug called spironolactone, which Pitt showed in 1999 had improved heart failure survival by blocking the hormone aldosterone.
-Dr. Michael Bristow of the University of Colorado reported on the effects of implanted devices that both resynchronize the heart and jolt it back into normal rhythm if cardiac arrest occurs. The study found a 43 percent reduction in death after one year in heart failure patients also getting standard treatments, including spironolactone.
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EDITOR'S NOTE: Medical Editor Daniel Q. Haney is a special correspondent for The Associated Press.
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