Stem cells shrink enlarged hearts, rejuvenate scar tissue

Songwriters may think that only love can mend a heart, but University of Miami cardiologists found that stem cell therapy can do it, too. In a small, preliminary human study, the researchers used stem cells from patients' bone marrow to replace scar tissue and shrink enlarged hearts by up to 25 percent. Current interventions only reduce the size of swollen hearts by about 5 percent, they said.

The marrow-derived stem cells were injected into scar tissue caused by heart attack, with the hope that the immature cells would turn the damaged tissue into heart muscle. They found that some of the injected cells did transform into heart muscle, but the cells also prompted the patient's heart to produce more of its own stem cells, which in turn became heart muscle, too.

On average, the study patients' hearts shrank by 15 to 20 percent, and scar tissue reduced by more than 18 percent. Heart function in the treated areas improved dramatically, the researchers found.

"That's the Holy Grail, the quest the whole field has been pursuing for close to a decade, and this is evidence we're on the right track," lead author Joshua Hare of the University of Miami said. The study appeared in Circulation Research: Journal of the American Heart Association.

This was a safety-oriented, eight-patient study. Next come two more trials, one comprising 60 patients and designed to further assess the procedure's efficacy and safety, and another to test whether donor bone marrow works as well as the patient's own bone marrow.

- check out the Miami Herald story
- see the abstract of the AHA study
- get more from the Science Blog