Composite cell sheets: a further step toward safe and effective myocardial regeneration by cardiac progenitors derived from embryonic stem cells.

Background: The safety and efficacy of myocardial regeneration using embryonic stem cells are limited by the risk of teratoma and the high rate of cell death.

Methods And Results: To address these issues, we developed a composite construct made of a sheet of adipose tissue-derived stroma cells and embryonic stem cell-derived cardiac progenitors. Ten Rhesus monkeys underwent a transient coronary artery occlusion followed, 2 weeks later, by the open-chest delivery of the composite cell sheet over the infarcted area or a sham operation.