Alain Bel, MD; Valérie Planat-Bernard, PhD, MD; Atsuhiro Saito, PhD; Lionel Bonnevie, MD; Valérie Bellamy, MSc; Laurent Sabbah, MD; Linda Bellabas; Benjamin Brinon, MSc; Valérie Vanneaux, MD, PhD; Pascal Pradeau, DVet; Séverine Peyrard, MSc; Jérôme Larghero, MD, PhD; Julia Pouly, MD; Patrice Binder, MD; Sylvie Garcia, PhD; Tatsuya Shimizu, PhD; Yoshiki Sawa, MD; Teruo Okano, PhD; Patrick Bruneval, MD; Michel Desnos, MD, PhD; Albert A. Hagège, MD, PhD; Louis Casteilla, PhD; Michel Pucéat, PhD; Philippe Menasché, MD, PhD

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 immunofluorescence 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 developmentally restricted SSEA-1 + cardiac progenitors appear to be safe and highlight the benefit of the epicardial delivery of a construct harboring cells with a cardiomyogenic differentiation potential and cells providing them the necessary trophic support.

To test the purported immune privilege of embryonic stem cells (ESC) in the challenging setting of xenotransplantation, 14 immunocompetent baboons were subjected to a coronary artery occlusion-reperfusion sequence and, two weeks later, randomized to receive in-scar injections of culture medium or cardiac-committed mouse ESC engineered to express fluorescent reporter genes driven by cardiac-specific promoters. Two months after transplantation, left ventricular function, as assessed by echocardiography, deteriorated to a similar extent in control and treated baboons. This correlated with failure to identify the grafted cells by X-gal histology and immunofluorescence. Rejection did not seem to be mediated by xenoantibodies, but rather by T lymphocytes and natural killer cells as suggested by positive immunostaining for CD3 and CD56 early after transplantation. There was no increase in circulating levels of regulatory T cells. These data raise a cautionary note about the immune privilege of ESC and suggest that from a mere immunologic standpoint, ESC xenotransplantation is likely to be an unrealistic challenge.