Heart failure is a leading cause of death in United States. One of the causes of heart failure is associated with the death or loss of cardiomyocytes (CMs). Since adult CMs do not regenerate, their death permanently compromises myocardial contractile function. Stem cell transplantation is one therapeutic strategy to replace damaged or lost myocardial tissue to restore cardiac function. Embryonic stem cells (ESCs) are an attractive population for cardiac repair because they can self-renew unlimitedly and differentiate into all cell types including CMs. Furthermore, ESC derived CMs can functionally integrate with the recipient organ and improve heart function after transplantation.

However, a major challenge in ESC-based cardiac therapies is that the differentiation efficiency of ESCs into CMs has been very low (~1%). And large numbers of cells are required for administration for each patient. In this study, a protocol for efficient generation of CMs from hESCs was explored by optimizing various staged components in the microenvironment. Specifically, I 1) developed Honeycomb Microwell chips to generate homogeneous EB for CM differentiation; 2) optimized Actvin A/BMP4 concentration for CM differentiation; 3) optimized effects of extracellular matrix (ECM) signaling and investigated some mechanisms of ECM signaling on CM differentiation. The optimized protocols reproducibly generate approximately 70% CMs from H7 and H9 hESCs. These hESC derived CMs can now be enriched and tested for their ability to enhance cardiac function in preclinical animal models and for utility in drug discovery for future study.