Researchers have used cardiac stem cells to regenerate heart muscle in patients who have suffered heart attacks, also known as myocardial infarction.
The small preliminary study, which was conducted by the Cedars-Sinai Heart Institute in Los Angeles, involved 25 patients who had suffered heart attacks in the previous one and a half to three months.
Seventeen of the study subjects received infusions of stem cells cultured from a raisin-sized chunk of their own heart tissue, which had been removed via catheter. The eight others received standard care.
During a heart attack, heart tissue is damaged, leaving a scar. On average, scars in patients who had the stem cell infusions dropped in size from 24% to 12% of the heart, said Dr. Eduardo Marbán, director of the Cedars-Sinai Heart Institute and lead researcher on the study, which was published online Monday in the journal The Lancet. (The journal has provided an abstract of the study; subscription is required for the full text.)
In an email, Marbán said he believed that the stem cells repaired the damaged heart muscle "indirectly, by stimulating the heart's endogenous capacity to regrow [which normally lies dormant]." He said that the most surprising aspect of the research team's finding was that the heart was able to regrow healthy tissue. Conventional wisdom holds that cardiac scarring is permanent.
A follow-up study involving about 200 patients is planned for later this year, Marbán added.
Last year, the Los Angeles Times wrote about efforts to develop therapies to reverse heart failure using several types of stem cells, including embryonic stem cells, cardiac stem cells and the stem cells found in bone marrow.