Video-based assessment of drug-induced effects on contractile motion properties using human induced pluripotent stem cell-derived cardiomyocytes.

INTRODUCTION: Drug-induced inotropic change is a risk factor in drug development; thus, de-risking is desired in the early stages of drug development. Unlike proarrhythmic risk assessment using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), few in vitro models were validated to predict cardiac contractility. Motion field imaging (MFI), a high-resolution block matching-based optical flow technique, was expected to possess high quantitative predictivity in the detection of contraction speed. We aimed to establish an in vitro model to assess drug-induced contractile changes using hiPSC-CMs and MFI. METHODS: MFI was designed to noninvasively characterize cardiomyocyte contractile behavior by analyzing light microscope video images, and maximum contraction speed (MCS) was used as the index of contractility. Using MFI, 9 inactive compounds, 10 negative inotropes, and 10 positive inotropes were tested. Two negative chronotropes, ZD7288 and ivabradine, were also tested. To determine the sensitivity and specificity of the assay, the minimum effective concentration of the MCS was compared with the human effective total therapeutic concentration for 28 compounds in clinical use. RESULTS: For 8 negative and 8 positive inotropes, the effects observed in in vivo and clinical studies were detected in MFI assay. MFI assay showed negative chronotropic changes without inotropic changes. MFI assay presented sufficient specificity (83%) and sensitivity (88%), and RNA-sequence analysis provided an insight into the relationship between occurrence of the false compounds and target gene expression. DISCUSSION: We demonstrated the utility of MFI assay using hiPSC-CMs to assess drug-induced contractile function. These results will facilitate the de-risking of compounds during early drug development.

Cell-based two-dimensional morphological assessment system to predict cancer drug-induced cardiotoxicity using human induced pluripotent stem cell-derived cardiomyocytes.

Recent developments of novel targeted therapies are contributing to the increased long-term survival of cancer patients; however, drug-induced cardiotoxicity induced by cancer drugs remains a serious problem in clinical settings. Nevertheless, there are few in vitro cell-based assays available to predict this toxicity, especially from the aspect of morphology. Here, we developed a simple two-dimensional (2D) morphological assessment system, 2DMA, to predict drug-induced cardiotoxicity in cancer patients using human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) with image-based high-content analysis in a high-throughput manner. To assess the effects of drugs on cardiomyocytes, we treated iPSC-CMs with 28 marketed pharmaceuticals and measured two key parameters: number of cell nuclei and sarcomere morphology. Drugs that significantly perturbed these two parameters at concentrations ≤30 times the human Cmax value were regarded as positive in the test. Based on these criteria, the sensitivity and specificity of the 2DMA system were 81% and 100%, respectively. Moreover, the translational predictability of 2DMA was comparable with that of a three-dimensional cardiotoxicity assay. RNA sequencing further revealed that the expression levels of several genes related to sarcomere components decreased following treatment with sunitinib, suggesting that inhibition of the synthesis of proteins that comprise the sarcomere contributes to drug-induced sarcomere disruption. Based on these features, the 2DMA system provides mechanistic insight with high predictability of cancer drug-induced cardiotoxicity in humans, and could thus contribute to the reduction of drug attrition rates at early stages of drug development.

CSAHi study-2: Validation of multi-electrode array systems (MEA60/2100) for prediction of drug-induced proarrhythmia using human iPS cell-derived cardiomyocytes: Assessment of reference compounds and comparison with non-clinical studies and clinical information.

With the aim of reconsidering ICH S7B and E14 guidelines, a new in vitro assay system has been subjected to worldwide validation to establish a better prediction platform for potential drug-induced QT prolongation and the consequent TdP in clinical practice. In Japan, CSAHi HEART team has been working on hiPS-CMs in the MEA (hiPS-CMs/MEA) under a standardized protocol and found no inter-facility or lot-to-lot variability for proarrhythmic risk assessment of 7 reference compounds. In this study, we evaluated the responses of hiPS-CMs/MEA to another 31 reference compounds associated with cardiac toxicities, and gene expression to further clarify the electrophysiological characteristics over the course of culture period. The hiPS-CMs/MEA assay accurately predicted reference compounds potential for arrhythmogenesis, and yielded results that showed better correlation with target concentrations of QTc prolongation or TdP in clinical setting than other current in vitro and in vivo assays. Gene expression analyses revealed consistent profiles in all samples within and among the testing facilities. This report would provide CiPA with informative guidance on the use of the hiPS-CMs/MEA assay, and promote the establishment of a new paradigm, beyond conventional in vitro and in vivo assays for cardiac safety assessment of new drugs.

Recapitulation of Clinical Individual Susceptibility to Drug-Induced QT Prolongation in Healthy Subjects Using iPSC-Derived Cardiomyocytes.

To predict drug-induced serious adverse events (SAE) in clinical trials, a model using a panel of cells derived from human induced pluripotent stem cells (hiPSCs) of individuals with different susceptibilities could facilitate major advancements in translational research in terms of safety and pharmaco-economics. However, it is unclear whether hiPSC-derived cells can recapitulate interindividual differences in drug-induced SAE susceptibility in populations not having genetic disorders such as healthy subjects. Here, we evaluated individual differences in SAE susceptibility based on an in vitro model using hiPSC-derived cardiomyocytes (hiPSC-CMs) as a pilot study. hiPSCs were generated from blood samples of ten healthy volunteers with different susceptibilities to moxifloxacin (Mox)-induced QT prolongation. Different Mox-induced field potential duration (FPD) prolongation values were observed in the hiPSC-CMs from each individual. Interestingly, the QT interval was significantly positively correlated with FPD at clinically relevant concentrations (r > 0.66) in multiple analyses including concentration-QT analysis. Genomic analysis showed no interindividual significant differences in known target-binding sites for Mox and other drugs such as the hERG channel subunit, and baseline QT ranges were normal. The results suggest that hiPSC-CMs from healthy subjects recapitulate susceptibility to Mox-induced QT prolongation and provide proof of concept for in vitro preclinical trials.