Several recent studies have illustrated the power of stem cells to heal damaged hearts following a heart attack. Now, a new study finds that injecting one’s own stem cells into the heart can reverse much of the damage that can linger for many years after the injury originally occurred.
The improvements in heart function were seen as early as three months after the stem cell injections, and continued for the length of the study (one year). No significant negative effects were reported as a result of the treatment.
In the study, researchers followed eight men who had suffered heart attack up to 11 years earlier. All of the men had poorly functioning, chronically enlarged hearts. When a heart is enlarged it can’t pump blood as effectively as a normal-sized, healthy heart. The researchers took stem cells from the men’s bone marrow and injected it into their hearts. They used cardiac MRI to study how the function and structure of the men’s hearts changed over time.
Some impressive changes occurred in the year following treatment. The size of the men’s hearts was reduced by 15-20%, which is significantly more than any current treatments can claim. The amount of scar tissue in the men’s hearts also declined by about 18%, and there was a big improvement in how well the hearts contracted to pump blood. The improvements in heart function were seen as early as three months after the stem cell injections, and continued for the length of the study (one year).
Lead researcher Joshua M. Hare points out, in the American Heart Association press release, that earlier studies had used different methods to measure heart function, which hadn’t proved to work very well in humans. Newer methods, like the ones used in this study, may allow researchers to better understand the changes that are occurring in the heart after stem cells are injected into human hearts.
The study’s early results are exciting and may lead to effective new treatments for chronically enlarged hearts. Hare is still cautious, however, saying that "we have yet to prove this clinical benefit — this is an experimental therapy in phase one studies." But he adds that "[t]hese findings support further clinical trials and give us hope that we can help people with enlarged hearts." Future research needs to look at the effectiveness of the treatment over the longer term, but the study certainly outlines a promising new avenue for heart research.
The study was conducted at the University of Miami’s Miller School of Medicine, and published in the March 17, 2011 online edition of Circulation Research: Journal of the American Heart Association.