Introduction: A priority in the development and approval of new drugs is assessment of cardiovascular risk. Current methodologies for screening compounds (e.g. HERG testing) for proarrhythmic risk lead to many false positive and false negative results, resulting in the attrition of potentially therapeutic compounds in early development, and the advancement of other candidates that cause adverse effects. With improvements in the technologies of high content imaging and human stem cell differentiation, it is now possible to directly screen compounds for arrhythmogenic tendencies in human stem cell derived cardiomyocytes (hSC-CMs).
Methods: A training panel of 90 compounds consisting of roughly equal numbers of QT-prolonging and negative control (non-QT-prolonging) compounds, and a follow-up blinded study of 35 compounds including 16 from the 90 compound panel and 2 duplicates, were evaluated for prolongation of the calcium transient in hSC-CMs using kinetic image cytometry (KIC), a specialized form of high content analysis.
Results: The KIC-hSC-CM assay identified training compounds that prolong the calcium transient with 98% specificity, 97% precision, 80% sensitivity, and 89% accuracy in predicting clinical QT prolongation by these compounds. The follow-up study of 35 blinded compounds confirmed the reproducibility and strong diagnostic accuracy of the assay.
Discussion: The correlation of the KIC-hSC-CM results to clinical observations met or surpassed traditional preclinical assessment of cardiac risk utilizing animal models. Thus, the KIC-hSC-CM assay, which can be accomplished in high throughput and at relatively low cost, is an effective new model system for testing chemicals for cardiovascular risk.
Keywords: 3Rs; Action potential; Calcium transient; Cardiac safety pharmacology; Cisapride (PubChem CID: 2769); Comprehensive in vitro Proarrhythmia Assay (CiPA); Dofetilide (PubChem CID: 71329); Droperidol (PubChem CID: 3168); Fluo 4AM (PubChem CID: 4060965); Haloperidol (PubChem CID: 3559); High-throughput; Human stem cell derived cardiomyocytes; Kinetic image cytometry; Methods; Pimozide (PubChem CID: 16362); QT; Quinidine (PubChem CID: 441074); Sematilide (PubChem CID: 58505); Sotalol (PubChem CID: 66245); Thioridazine (PubChem CID: 5452).
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