However, scores on the Minnesota Living with Heart Failure Questionnaire decreased to the same degree in the two study groups. And both groups also showed nonsignificant changes in left-ventricular ejection fraction at 6 months.
Both regional contractility and systolic wall thickening improved in the stem cell group but worsened in the control group.
Previous studies have reported small reductions in scar size after infusions of bone marrow mononuclear cells, mesenchymal cells, and another heart-derived cell product, purified c-KIT–positive cells. However, animal studies demonstrate that the cardiosphere-derived cells used in this study outperform all of them "in terms of paracrine potency, antiapoptotic properties, tissue engraftment, and regenerative efficacy," the CADUCEUS researchers said.
"This discovery challenges the conventional wisdom that, once established, cardiac scarring is permanent and that, once lost, healthy heart muscle cannot be restored," they concluded.
CADUCEUS was supported by the National Heart, Lung, and Blood Institute and Cedars-Sinai Heart Stem Cell Center. Dr. Makkar’s associates reported ties to Capricor, a biotech company that develops and commercializes cardiac stem cell treatments.