Abstract 13789: Developing Xeno-Free Human Induced Pluripotent Stem Cell-Derived Cardiac Construct for Regeneration Therapy Using a Rat Myocardial Infarction Model
Background: Use of induced pluripotent stem cells (hiPSC) is promising to establish cardiac regenerative medicine in clinical arena; however, safety is concerned by regulatory scientific view, including use of xeno-biological materials for production of the graft. We have explored synthetic small molecules, KY, instead of standard xeno-materials to induce cardiomyogenic differentiation, such as BMP4, Activin A or insulin. We herein studied therapeutic efficacy of hiPSC-derived cardiomyocytes (CMs) generated by xeno-free condition on chronic myocardial infarction (MI) in rat. Methods: Lentivirus vector carrying Oct3/4, Sox2 and Klf4 was transfected in human dermal fibroblasts to establish hiPSC cell-line. KY was added to the hiPSCs, which displayed 80±10%-positivity in cardiac-troponin T. Scaffold-free cardiac graft was produced by hiPSC-CMs that were cultured in thermoresponsive dishes, and transplanted over the cardiac surface of athymic nude rats that were subjected to left coronary artery ligation 2 weeks prior to the treatment, or sham operation was performed. Results: Echocardiographically, ejection fraction recovered after the treatment in the hiPSC-CM group (48±4% at baseline, 55±4% at 1 week, 55±4% at 2 weeks, and 56±3% at 4 weeks), whereas the sham group showed gradual reduction in ejection fraction (46±5% at baseline, 42±5% at 1 week, 38±4% at 2 weeks, and 34±6% at 4 weeks). Immunohistochemistry showed that cardiac-troponin T and human nuclear antigen double positive-hiPSC-CMs were present in the lateral cardiac surface in the hiPSC-CM hearts. In the hiPSC-CM group, collagen fibers significantly decreased in the infarct-border and remote areas (p<0.01 and p<0.01, respectively). CD31-positve capillary number in the infarct-border area was significantly greater in the hiPSC-CM group (p<0.01) than the sham group. Conclusion: Transplantation of scaffold-free human iPSC-CMs grafts produced by xeno-free synthetic small molecules was effective on rat chronic MI heart, warranting further studies to optimize production of iPSC-based artificial cardiac graft for cardiac regeneration therapy.