The Biomimetic Cardiac Tissue Model (BCTM) Enables the Adaption ofHuman Induced Pluripotent Stem Cell Cardiomyocytes (iPSC-CMs) to PhysiologicalHemodynamic Loads

摘要

Induced pluripotent stem cell derived cardiomyocytes (iPSC-CMs) provide a human source of cardiomyocytes for use in cardiovascular research and regenerative medicine. However, attempts to use these cells in vivo have resulted in drastic cell death caused by mechanical, metabolic, and/or exogenous factors. To explore this issue, we designed a Biomimetic Cardiac Tissue Model (BCTM) where various parameters associated with heart function including heart rate, peak-systolic pressure, end-diastolic pressure and volume, end-systolic pressure and volume, and ratio of systole to diastole can all be precisely manipulated to apply hemodynamic loading to culture cells. Using the BCTM, two causes of low survivability in current cardiac stem cell therapies, mechanical and metabolic, were explored. iPSC-CMs were subject to physiologically relevant mechanical loading (50 mmHg systolic, 10% biaxial stretch) in either a low- or high-serum environment and mechanical loads were applied either immediately or gradually. Results confirm that iPSC-CMs subject to mechanical loading in low-serum conditions experienced widespread cell death. The rate of application of stress also played an important role in adaptability to mechanical loading. Under high-serumconditions, iPSC-CMs subject to gradual imposition of stress were comparable toiPSC-CMs maintained in static culture when evaluated in terms of cell viability,sarcomeric structure, action potentials and conduction velocities. In contrast,iPSC-CMs that were immediately exposed to mechanical loading had significantlylower cell viability, destruction of sarcomeres, smaller action potentials andlower conduction velocities. We report that iPSC-CMs survival underphysiologically relevant hemodynamic stress requires gradual imposition ofmechanical loads in a nutrient-rich environment.