Final results of a study conducted at Johns Hopkins show that stem cell therapy can be used effectively to treat heart attacks, or myocardial infarction, in pigs. In just two months, stem cells harvested from another pig's bone marrow and injected into the animal's damaged heart restored heart function and repaired damaged heart muscle by 50 percent to 75 percent.
The Hopkins findings, first presented last fall at the 2004 Scientific Sessions of the American Heart Association, are to be published in the latest issue of the Proceedings of the National Academy of Sciences online the week of July 25.
Two patients have already been enrolled at Hopkins in a Phase I clinical trial, which is designed to test the safety of injecting adult stem cells at varying doses in patients who have recently suffered a heart attack. In total, 48 patients will participate in this study, which is happening at several sites across the country. Results are not expected until mid-2006.
"Ultimately, the goal is to develop a widely applicable treatment to repair and reverse the damage done to heart muscle that has been infarcted, or destroyed, after losing its blood supply," says cardiologist Joshua Hare, M.D., professor of medicine at The Johns Hopkins University School of Medicine and its Heart Institute, and senior author of the study and lead trial investigator.
"There is reason for optimism about these findings, possibly leading to a first-ever cure for heart attack in humans," he says. "If a treatment can be found for the damage done by a heart attack to heart muscle, then there is the potential to forestall the serious complications that traditionally result from a heart attack, including disturbances of heart rhythm that can lead to sudden cardiac death, and decreased muscle pumping function that can lead to congestive heart failure."
The researchers are using a special kind of stem cell in an early stage of development, called adult mesenchymal stem cells, to avoid potential problems with immunosuppression, in which every human's immune system might attack stem cells from sources other than itself. Bone marrow adult stem cells do not have the same potential to develop into different organ tissues, as do embryonic stem cells, whose use is more controversial.