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NIH Study: Stem-Cell Therapy Doesn’t Improve Short-Term Recovery After Heart Attack
Administering stem cells derived from patients’ own bone marrow either 3 or 7 days after a heart attack is safe but does not improve heart function 6 months later, according to a clinical trial supported by the National Institutes of Health (NIH).
The results of the Transplantation In Myocardial Infarction Evaluation (TIME) trial mirror those of a previous study (LateTIME), which found that autologous stem cells given 2 to 3 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.
The findings were published in the November 6 issue of the Journal of the American Medical Association.
Between July 2008 and February 2011, TIME researchers enrolled 120 volunteers (average age: 57 years; 87.5% male) who had moderate to severe left ventricular impairment and who had undergone stenting procedures following heart attacks. Those selected for the trial were randomly assigned to one of four treatment groups: stem-cell injection on day 3 after the heart attack; placebo injection on day 3 after the heart attack; stem-cell treatment on day 7 after the heart attack; or placebo treatment on day 7 after the heart attack.
The researchers developed a method of processing and purifying the stem cells to ensure that participants in the stem-cell groups received a uniform dose of 150 million cells approximately 8 hours after the cells were harvested from the patients’ bone marrow. This ensured that the results would not be skewed by differences in the quantity or quality of the stem cells administered.
The researchers assessed heart improvement at 6 months after stem-cell therapy by measuring the percentage of blood that was pumped out of the left ventricle during each contraction (i.e., the left ventricular ejection fraction [LVEF]). The study found no significant differences between the change in LVEF readings at the 6-month follow-up in either the day 3 or the day 7 stem-cell groups compared with the placebo groups or with each other. Every group showed about a 3% improvement in LVEF.
Source: NIH; November 5, 2012.