The lack of measurable single cell contractility of human induced pluripotent stem cell-derived cardiac myocytes (hiPSC-CMs) currently limits the utility of hiPSC-CMs for evaluating contractile performance for both basic research and drug discovery.To develop a culture method that rapidly generates contracting single hiPSC-CMs and allows quantification of cell shortening with standard equipment used for studying adult cardiac myocytes (CMs).Single hiPSC-CMs were cultured for 5 - 7 days on a 0.4 - 0.8 mm thick mattress of undiluted Matrigel ("mattress hiPSC-CM") and compared to hiPSC-CMs maintained on control substrate (<0.1 mm thick 1:60 diluted matrigel, "control hiPSC-CM"). Compared to control hiPSC-CM, mattress hiPSC-CMs had more rod-shape morphology and significantly increased sarcomere length. Contractile parameters of mattress hiPSC-CMs measured with video-based edge detection was comparable to that of freshly isolated adult rabbit ventricular CMs. Morphological and contractile properties of mattress hiPSC-CM were consistent across cryopreserved hiPSC-CMs generated independently at another institution. Unlike control hiPSC-CM, mattress hiPSC-CMs display robust contractile responses to positive inotropic agents such as myofilament calcium sensitizers. Mattress hiPSC-CMs exhibit molecular changes that include increased expression of the maturation marker cardiac troponin I and significantly increased action potential upstroke velocity due to a 2-fold increase in sodium current (INa).The Matrigel mattress method enables the rapid generation of robustly contracting hiPSC-CMs and enhances maturation. This new method allows quantification of contractile performance at the single cell level, which should be valuable to disease modeling, drug discovery and preclinical cardiotoxicity testing.
View details for PubMedID 26429802