1-(3-sulfonatopropyl)-4-(beta)(2-(di-n-butylamino)-6-naphthylvinyl)pyridinium-betaine and Cardiotoxicity

Because cardiotoxicity is one of the leading causes of drug failure and attrition, the design of new protocols and technologies to assess proarrhythmic risks on cardiac cells is in continuous development by different laboratories. Current methodologies use electrical, intracellular Ca2+, or contractility assays to evaluate cardiotoxicity. Increasingly, the human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are the in vitro tissue model used in commercial assays because it is believed to recapitulate many aspects of human cardiac physiology. In this work, we demonstrate that the combination of a contractility and voltage measurements, using video-based imaging and fluorescence microscopy, on hiPSC-CMs allows the investigation of mechanistic links between electrical and mechanical effects in an assay design that can address medium throughput scales necessary for drug screening, offering a view of the mechanisms underlying drug toxicity. To assess the accuracy of this novel technique, 10 commercially available inotropic drugs were tested (5 positive and 5 negative). Included were drugs with simple and specific mechanisms, such as nifedipine, Bay K8644, and blebbistatin, and others with a more complex action such as isoproterenol, pimobendan, digoxin, and amrinone, among others. In addition, the results provide a mechanism for the toxicity of itraconazole in a human model, a drug with reported side effects on the heart. The data demonstrate a strong negative inotropic effect because of the blockade of L-type Ca2+ channels and additional action on the cardiac myofilaments. We can conclude that the combination of contractility and action potential measurements can provide wider mechanistic knowledge of drug cardiotoxicity for preclinical assays.

Topics: Action Potentials; Arrhythmias, Cardiac; Calcium Channels, L-Type; Cardiotoxicity; Cell Differentiation; Cells, Cultured; Excitation Contraction Coupling; Fluorescent Dyes; Humans; Induced Pluripotent Stem Cells; Microscopy, Fluorescence; Microscopy, Video; Myocardial Contraction; Myocytes, Cardiac; Myofibrils; Pyridinium Compounds; Risk Assessment; Time Factors; Toxicity Tests

Topics: Action Potentials; Arrhythmias, Cardiac; Cardiotoxicity; Cell Differentiation; Cell Line; Dose-Response Relationship, Drug; Fluorescent Dyes; Humans; Induced Pluripotent Stem Cells; Myocytes, Cardiac; Photometry; Pyridinium Compounds; Risk Assessment; Signal Processing, Computer-Assisted; Time Factors; Toxicity Tests; Voltage-Sensitive Dye Imaging