MIAMI, Florida, March 23, 2011 ( – A new study shows that adult stem cells may hold the key to healing cardiac injuries and reducing the need for heart transplant surgeries.

The results of a trial study of eight patients are recorded in Circulation Research: Journal of the American Heart Association, and show that when adult stem cells were injected into enlarged hearts, they reduced heart volume, scar tissue, and revitalized damaged areas.

“The injections first improved function in the damaged area of the heart and then led to a reduction in the size of the heart. This was associated with a reduction in scar size. The effects lasted for a year after the injections, which was the full duration of the study,” said Joshua M. Hare, M.D., the study’s senior author.

Hare is professor of medicine and director of the Interdisciplinary Stem Cell Institute at the University of Miami in Florida.

Hare notes that more than five million Americans have hearts that become damaged and enlarged due to heart attacks, which can lead to further severe health complications or even death.

The scientist cautioned that while the early phases suggested the stem cell procedure could improve the lives of people with enlarged hearts by giving them better functioning hearts with more normal structure, more studies will be needed to prove that benefit. Nevertheless, he said, “the findings support further clinical trials and give us hope that we can help people with enlarged hearts.”

The study suggests that patients may one day have options other than constant heart medication or even major invasive procedures such as heart transplantation.

Researchers injected two kinds of adult stem cells – mononuclear and mesenchymal – into the heart through a catheter. Eight men (averaging 57 years old) with enlarged, damaged hearts participated in the study.

The study reports that after one year, the size of the heart decreased overall 15 – 20 percent. The researchers say this is almost three times what is possible with current treatments. Also, scar tissue diminished overall by 18.3 percent, and the targeted areas of the heart showed substantially improved function.

“This therapy improved even old cardiac injuries,” Hare said. “Some of the patients had damage to their hearts from heart attacks as long as 11 years before treatment.”

Adult stem cells have enjoyed enormous successes in pioneering new therapies and treatments for a variety of illnesses, expanding the limits of current medical frontiers. In contrast, embryonic stem cells have presented a number of medical drawbacks – in addition to the major ethical issues of destroying an early-stage human embryo – for treatment of patients, including tumors and immune system rejection.

In a related recent success, the media in Spain reported in March that a four-year-old girl has been cured of a brain tumor thanks to a transplant of adult stem cells derived from umbilical cord blood, which her parents had banked away at the child’s birth. Now, 16 months after a stem cell treatment restored the child’s blood system, which was devastated by chemotherapy treatments, the girl remains cancer free. She will be certified as officially “cured” by doctors only after living a total of five years without a relapse.