Health After 50
The Potential of Stem Cell Therapy to Heal the Heart
Researchers are finding that stem cell therapy does have a modest effect on heart function in patients who have recently had a heart attack. When injected into the body after a heart attack, stem cells appear to repair heart tissue and improve heart function.
Theories on How It Works How does stem cell therapy perform its "magic"? Experts aren't sure exactly, but the latest research suggests that the expected effect of stem cells -- morphing into heart muscle cells that generate new heart tissue -- is likely not the major mechanism.
Instead, it appears that stem cells "home" to the area of heart damage, acting like microscopic paramedics rushing to the scene of an accident. In effect, the damaged heart tissue issues a chemical 911 call that attracts stem cells to the correct address in the body. When these stem cells reach the injured portion of the heart, they release their own compounds that help limit damage to the heart muscle and enhance healing -- by quenching inflammation, decreasing cell death, spurring the growth of new blood vessels and reducing scar formation at the site of damage. In essence, the stem cells are providing the heart with the tools to aid recovery and regeneration.
Before stem cell therapy becomes a part of the mainstream treatment of heart attacks, researchers need to answer some key questions about the therapy.
- Type of stem cell. It's not yet clear which type of stem cells works best for the treatment of heart attacks. Besides heart, mononuclear, and mesenchymal stem cells, other types under investigation include inducible pluripotent stem cells, which act similarly to embryonic stem cells but are generated from adult cells.
- Mode of administration. Direct infusion of the stem cells into the affected coronary artery is the most popular mode of administration. But other methods, like infusion into a vein or direct injection into the heart, appear to work as well. More research is needed to identify the preferred technique.
- How much is enough? The studies conducted so far have used a wide range of stem cell numbers, and the optimal number and whether this varies depending on the amount of damaged heart tissue are not yet known.
- Timing of administration. One 2009 analysis in Clinical Cardiology of seven randomized, controlled trials found that the timing of mesenchymal stem cell administration makes a difference in the effectiveness of the treatment. In particular, an infusion given four to seven days after a heart attack significantly improved heart function, while an injection given within 24 hours did not. Whether receiving stem cell therapy more than a week after a heart attack can still be beneficial is unknown.
Looking to the future. Stem cell therapy is available only through clinical trials, and many questions still remain about how the treatment works and the best way to deliver stem cells to provide maximum benefit. If you are interested in joining a clinical trial, check out the National Institutes of Health-sponsored website at www.clinicaltrials.gov. At the site, you can search for the terms "heart attack" and "stem cells" to find out if there are any studies near you that are recruiting participants.
Posted in Heart Health on April 20, 2012
Medical Disclaimer: This information is not intended to substitute for the advice of a physician. Click here for additional information: Health After 50 Disclaimer
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