Results of a clinical trial show that administering stem cells to patients derived from their own bone marrow either three or seven days after a heart attack is safe but does not improve heart function six months later.
The results of the trial, called Transplantation In Myocardial Infarction Evaluation (TIME), mirror a previous, related study, LateTIME, which found that such cells (called autologous stem cells) given two to three weeks after a heart attack did not improve heart function.
Both TIME and LateTIME were conducted by the Cardiovascular Cell Therapy Research Network (CCTRN), sponsored by the NIH's National Heart, Lung, and Blood Institute.
"This study was extremely valuable even though it did not provide a demonstrated health benefit after six months," said Sonia Skarlatos, Ph.D., deputy director of NHLBI's Division of Cardiovascular Sciences and member of the CCTRN.
"Heart stem cell therapy research is still in its infancy, and results from early trials have varied greatly due to differences in the numbers of stem cells injected, the delivery methods used, and the compositions of the study populations. With TIME and LateTIME, we have established both safety and baseline results in two large studies that followed the same procedures for growing and then administering stem cells. This standard will inform the next steps in research on the use of stem cells to repair damaged hearts," she stated.
Fellow CCTRN member Jay Travese, M.D., of the Minneapolis Heart Institute added, "With this baseline now set, we can start to adjust some of the components of the protocol to grow and administer stem cell to find cases where the procedure may improve function."
"For example, this therapy may work better in different population groups, or we might need to use new cell types or new methods of delivery," he noted.
Skarlatos said that another advantage of the TIME study is that CCTRN is storing samples of the stem cells taken from the participants. Investigators can examine the relationship between people who showed significant improvement during the study and the characteristics of their stem cells. Such a comparison may offer insights on the cell traits that are associated with clinical improvement.
The findings will be presented at the American Heart Association (AHA) 2012 Scientific Sessions in Los Angeles and will appear concurrently in the Journal of the American Medical Association.