Drug-induced cardiotoxicity plays a central role in the non-clinical testing. Applications of iPS-derived cardiomyocytes (iPS-CMs) hold great promise as a human cell-based platform. To date, multielectrode array (MEA) system has been widely used as a standardized assay to detect proarrhythmic risk with iPS-CMs. In addition, the importance of inotropic effects in vivo is recognized in a safety pharmacology through drug development. Given its impact on drug development, it should be useful to detect the drug-induced effects on contractility in vitro. Although many detection systems have been developed to monitor contractility in CMs, the standardized protocols have not been well established.
To compare contractility detection systems with iPS-CMs, we used iPS-CMs (iCell Cardiomyocyte, CDI) with cell motion imaging system (CMI) and the measurement of cell-induced electrical impedance (IMP). To determine suitable parameters to assess drug-induced contractility, we used isoproterenol and verapamil as reference compounds. By sequential recordings of CMI and IMP, we found common parameters to detect contractility between CMI and IMP. Our results suggest that both CMI and IMP can be used to monitor contractility in iPS-CMs. We are planning to evaluate the usefulness of these parameters by using more compounds, such as anti-cancer drugs.