Abstract P1041: Multiplexed Cardiotoxicity And Efficacy Screening Using Kinetic Image Cytometry Of Human Induced Pluripotent Stem Cell-derived Cardiomyocytes

Traditionally, cardiotoxicity testing used low-throughput animal models which may not fully recapitulate human physiology. Stem cell technology enables screening in a more physiologically-relevant model system in less time and with less cost, but most current high-throughput screening modalities rely on whole-well or whole-field averaged data, which obfuscate the responses of individual hiPSC-cardiomyocytes (CMs). By measuring individual hiPSC-CMs, heterogenous responses that would otherwise be “averaged out” can be quantified, thus improving sensitivity. We previously published that the single-cell Kinetic Image Cytometry (KIC) methods developed at Vala Sciences predicted arrhythmogenic liability with an accuracy of 90% using intracellular Ca 2+ kinetics as a readout. In this study, we expand upon this methodology by loading metabolically matured hiPSC-CMs with Cal-520 (a green Ca 2+ dye) and BeRST-1 (a far red membrane voltage dye), acquiring interleaved movies of Ca 2+ and membrane potential at 60 Hz (30 Hz per channel). We then created image analysis algorithms to measure Ca 2+ transient (CT) and action potential (AP) kinetics, and to derive contraction measurements from those movies. To validate our approach, we exposed cells to isoproterenol, nifedipine, dofetilide, and butadiene 2-monoxime (BDM) at various concentrations. Isoproterenol increased beat rate, decreased both AP and CT durations, increased CT magnitude, and elicited a lusitropic effect. Nifedipine increased beat rate, decreased AP and CT durations, and reduced CT magnitude and contraction distance. Dofetilide reduced beat rate, prolonged APs and CTs, and increased contraction distance. BDM had multiple inhibitor effects on APs and CTs, and strongly reduced contraction. Thus, this multiplexed assay can quantify multiple effects of drugs on APs, CTs, and contraction, providing an unprecedented suite of information relevant to cardiosafety and efficacy.