In human and animal studies, scientists at Johns Hopkins have developed a fast and safe method for collecting heart stem cells from remarkably small amounts of biopsied heart tissue (15 mg or less), and growing the cells in the lab to get more.
The technique gets the job done within four weeks, producing enough stem cells to conceivably be used to repair heart tissue clinically. The resulting clusters, called cardiospheres, contain cells that retain the ability to regenerate themselves, and to develop into more specialized heart cells that can conduct electrical currents and contract like heart muscle should.
Their findings, if affirmed in further clinical trials, could potentially offer patients a means of using their own stem cells to repair heart tissue soon after they have suffered a heart attack, or to regenerate weakened muscle resulting from heart failure, perhaps averting the need for heart transplants. By using a person's own adult stem cells instead of those from another donor, there would be no risk of triggering an immune response that could cause rejection.
Adult stem cells can be found in most living organ tissue, such as the heart, and can generally develop into related cell types, unlike embryonic stem cells that can become any type of cell or tissue in the body.
"Harnessing the potential benefits of therapy with adult stem cells is imperative if we are to make rapid progress in treating heart disease. Cardiac stem cells, grown from the heart itself, offer particular promise in that they can regenerate beating heart muscle," said Eduardo Marban, M.D., Ph.D., professor and chief of cardiology at The Johns Hopkins University School of Medicine and its Heart Institute, and lead investigator of the study to be presented at the American Heart Association's Scientific Sessions 2004 on Nov. 8. Marban is also director of the Johns Hopkins Institute of Molecular Cardiobiology.
"Our basic research is trying to overcome the biological problems in harnessing heart stem cells, so we are very excited about our success in growing and analyzing these cells," he said.
Using cardiac catheterization, where a tubelike probe is inserted into a vein in the neck that links to the heart, the Johns Hopkins team removed a small sample (15 mg or less) of heart tissue, from the right ventricle in 23 patients already undergoing treatment for heart failure. Earlier studies in pigs found that adult stem cells were most abundant in this region of the heart. Most other researchers use invasive surgery to obtain larger portions of muscle tissue, to increase the number of adult stem cells harvested. An added benefit to catheterization is that it can also be performed quickly, in less than 20 minutes.