Abstract 14377: Therapeutic Potential of Clinical Grade Human Induced Pluripotent Stem Cell-derived Cardiac Tissues for a Rat Myocardial Infarction Model: A Pre-clinical Study for a Cell Transplantation Therapy

Abstract

Introduction: Transplantation of three-dimensional bioengineered cardiac tissues composed of pluripotent stem cell-derived cardiovascular cell lineages is reported to hold potential for functional recovery on pre-clinical studies. We aimed to evaluate therapeutic and myocardial regenerative potential of clinical grade human induced pluripotent stem cell (hiPSC)-derived cardiac tissues (HiCTs) on a rat myocardial infarction (MI) model. Methods: Clinical grade hiPSC lines established from a healthy volunteer were simultaneously differentiated into cardiovascular cell lineages. We seeded the cells on temperature responsive culture dishes to form cell sheets. HiCTs were generated by stacking 5 cell sheets with insertion of gelatin hydrogel microspheres (GHMs) to promote oxygen and nutrition supply and transplanted onto an athymic rat MI model (n=6). Echocardiography and histological analysis at 12 weeks after surgery were conducted and compared to those in animals with sham surgery (n=9) and with cell sheet stacks without GHMs [GHM(-), n=6]. Some of HiCT-transplanted rats were subjected to tissue clearing and two-photon excitation microscopy (TPEM) to assess graft vascularization. Results: Flow cytometry revealed cellular components after differentiation as follows: 52.0±1.4% of cardiomyocytes (cardiac isoform of troponin-T + :cTnT), 9.9±0.7% of vascular endothelial cells (VE-cadherin + ) and 14.1±1.8% of vascular mural cells (PDGFRβ + ). Echocardiography revealed significantly lower left ventricular end diastolic volume (LVEDV) and higher left ventricular ejection fraction (LVEF) in HiCT group [sham vs GHM(-) vs HiCT: LVEDV; 1.5±0.1 vs 1.3±0.05 vs 0.9±0.03 mL, p<0.0001 / LVEF; 59.7±2.2 vs 67.4±0.6 vs 82.7±0.9 %, p<0.0001]. HiCT group showed significantly larger engraftment [GHM(-) vs HiCT; 12 week; 0.1 ± 0.1 vs 1.8 ± 0.6 mm 2 ; p<0.05]. Engrafted graft tissues were composed of cTnT / α-Actinin-positive cardiomyocytes which exhibited obvious striated structure. TPEM revealed host to graft vascular connection at 2 weeks after HiCT transplantation. Conclusions: HiCTs derived from clinical grade hiPSC potentially serve as a stem cell-derived cellular product in cardiac regenerative therapy for foreseeable clinical applications.