Microenvironment for hiPSC-derived pacemaking cardiomyocytes

Electronic pacemakers have numerous inherent deficiencies, such as limited sensitivity to changes in physical activities of recipients and necessary surgeries for battery replacement every 5-10 years for the recipients. Biopacemakers composed of human pacemaking cells similar to those in the native cardiac pacemaking tissue can circumvent these deficiencies that are inherent in the electronic devices. One potential source of human pacemaking cells is through derivation from the human induced pluripotent stem cells (hiPSCs). This award has enabled our laboratory to optimize the differentiation protocol and the microenvironment to induce hiPSC-derived heart cells to behave functionally more like the pacemaking rather than the contractile type. This is the first step towards having the right components for engineering biopacemakers.

Electronic pacemakers have numerous inherent deficiencies, such as limited sensitivity to changes in physical activities of recipients and necessary surgeries for battery replacement every 5-10 years for the recipients. Biopacemakers composed of human pacemaking cells similar to those in the native cardiac pacemaking tissue can circumvent these deficiencies that are inherent in the electronic devices. We proposed to develop pacemaking tissue constructs that may serve as biopacemakers by incorporating human induced pluripotent stem cell (hiPSC)-derived heart muscle cells in matrix scaffold from the pig pacemaking tissue, the sinoatrial node. In this study, we developed a new differentiation method that can yield up to 2.4 times more pacemaking heart muscle cells from the hiPSCs. We also demonstrated that the extracellular matrix environment is critical in inducing the pacemaking function and also in maintaining the function when subjected to cyclic mechanical strain that mimics the cardiac environment. Our research will continue to understand the mechanisms and the factors in the extracellular matrix of the native pacemaking tissue that resulted in the observed sustained pacemaking function in hiPSC-derived heart muscle cells.