Four research studies presented at Scientific Sessions point to new directions that offer the first promising results in several years.
?This is a new, refreshing appetizer for what may be an excellent meal in years to come,? said Valentin Fuster, M.D., Ph.D., American Heart Association past president and director of the Weiner Cardiovascular Institute and the Davis Center for Cardiovascular Health at Mount Sinai Medical Center in New York, NY, during a Tuesday news conference.
?Study results in the past couple of years have been equivocal at best. These four papers all use different sources of stem cells and all show great promise.?
Pediatric cardiologists can take hope in a Swiss project. Simon Hoerstrup, M.D., Ph.D., and his colleagues used stem cells derived from amniotic fluid to grow heart valves on a scaffold of biodegradable polymers. The goal is to create working valves that can be implanted in newborns.
?The advantage is that these valves come from the baby?s own cells. We can prefabricate a heart valve that can be ready to implant at the time of birth. It will not be rejected and can grow with the child,? said Dr. Hoerstrup, professor of biomedical engineering and director of cardiovascular research and the division of regenerative medicine in the department of surgical research at University Hospital, Zurich, Switzerland.
At the other end of the age spectrum, Paul DiMuzio, M.D., associate professor of surgery at Thomas Jefferson University, Philadelphia, found that stem cells harvested from the abdominal fat of elderly patients are as viable as adipose stem cells harvested from younger patients.
?A major problem for tissue engineers is a reliable source of cells,? Dr. DiMuzio explained. ?The supply of stem cells in blood and bone marrow decreases with age. Stem cells in fat remain viable into old age.?
Researchers used liposuction to remove about 15 grams of adipose tissue from 49 elderly patients. After seven days of culture, the cells were inspected and tested for viability.
?We were pleasantly surprised,? Dr. DiMuzio said. ?As you go from decade to decade (in age), we did not see a decline in the harves
t of stem cells. They all look the same, they are all healthy, and they all grow well.? German researchers found that bone marrow stem cells speed functional recovery following major heart attacks. The more severe the infarction, the greater the benefit. ?The sicker the patient, the greater the impact on ejection fraction,? said Thorsten Dill, M.D., of the Department of Cardiology and Cardiac Imaging, Kerckhoff-Heart Center, Bad Nauheim, Germany. ?Bone marrow stem cells hold great promise to limit infarct damage.?
For another researcher, the bone marrow could be the ultimate source of stem cells. Canadian researchers found that commercially available human marrow stromal cells do not elicit immune rejection when injected into rat heart tissue after induced myocardial infarct.
?Marrow stromal cells may be universal donor cells,? said Ray Chiu, M.D., Ph.D., professor of surgery and chair emeritus at McGill University Health Center, Montreal. ?It looks like they may be tolerated by everybody, even between species.?