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. The sheet was made of adipose tissue–derived stroma cells grown from a biopsy of autologous adipose tissue and cultured onto temperature-responsive dishes. Allogeneic Rhesus embryonic stem cells were committed to a cardiac lineage and immunomagnetically sorted to yield SSEA-1 cardiac progenitors, which were then deposited onto the cell sheet. Cyclosporine was given for 2 months until the animals were euthanized. Preimplantation studies showed that the SSEA-1 progenitors expressed cardiac markers and had lost pluripotency. After 2 months, there was no teratoma in any of the 5 cell-treated monkeys. Analysis of 1500 histological sections showed that the SSEA-1 cardiac progenitors had differentiated into cardiomyocytes, as evidenced by immunofluo-rescence and real-time polymerase chain reaction. There were also a robust engraftment of autologous adipose tissue–derived stroma cells and increased angiogenesis compared with the sham animals. Conclusions—These data collected in a clinically relevant nonhuman primate model show that developmentall