Cardiomyocytes Derived from Human Induced Pluripotent Stem Cells: An In-Vitro Model to Predict Cardiac Effects of Drugs

Abstract

Introduction: Cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CM) form spontaneously beating syncytia in-vitro. We evaluated whether hiPSC-CM are a compelling model of human cardiac pharmacology useful for early drug development. Methods: We measured hiPSC-CM beating frequency using Ca-sensitive dyes and a high-throughput screening system. We quantified the effects of 640 drugs with various structures and pharmacologies. Results: When tested at 1 µM, most drugs without direct effects on heart rhythm or with effects at high concentrations do not change frequency, indicating specificity. In contrast, the preparation detects compounds with direct activity on heart rhythm, demonstrating sensitivity. In particular, β-adrenergic agonists increase frequency and the model differentiates β2 from β1 agonists, as well as partial from full agonists. Phosphodiesterase inhibitors have subtype-specific actions and PDE4 is particularly important in controlling frequency. The preparation is sensitive to cardiac ion channel blockers: L-type calcium channel blockers, Class-I and Class-III antiarrhythmics change frequency but drugs acting on K ATP channels do not. The assay detects compounds blocking the cardiac rapid delayed-rectifier K channel and is an alternative to the classic "hERG test".Conclusion: hiPSC-CM are a useful in-vitro cardiac model in drug development since they respond appropriately to drugs that modify heart rate in humans.

Contractions of Human-iPSC-derived Cardiomyocyte Syncytia Measured with a Ca-sensitive Fluorescent Dye in Temperature-controlled 384-well Plates

“…In a validation study performed with many drugs approved for human use, we showed that the assay reacts to drugs used in human medicine as predicted by existing clinical data 5 . Because this method considers all potential effects on cardiac rhythm, it complements the Comprehensive in vitro Proarrhythmic assay (CiPA) initiative 14 that specifically assesses pro-arrhythmic potential.…”

“…Blockers of cardiac ion channels affect the rhythm of the cardiomyocytes in a reproducible manner 5 . Amlodipine, a blocker of the slow Ca channels 9 , accelerates the rhythm more than 100% in a concentration-dependent manner up to 1 µM ( Figure 2A ).…”

“…These hiPSC-CM can be obtained in large numbers through commercial providers or through production in the laboratory, and they are a useful source of cells to generate models of human cardiac physiology and pharmacology. In particular, they can be used to predict or to characterize cardiac effects that may occur when a drug is administered to humans 5 .…”

A deep learning algorithm to translate and classify cardiac electrophysiology

“…We updated network parameters ( +1 ) using adaptive momentum estimation (ADAM) optimization algorithm [79] based on the average gradient of overall loss function with respect to the network parameters for 64 randomly selected simulated AP traces (mini-batch = 64) at each training iteration (Eqs. [13][14][15].…”

A deep learning algorithm to translate and classify cardiac electrophysiology: From induced pluripotent stem cell-derived cardiomyocytes to adult cardiac cells

“…While in vitro iPSC-CM utilization allows for observation of a variety of responses to drugs and other perturbations [9][10][11][12], there is still a major inherent limitation: The complex differentiation process to create iPSC-CMs results in a model of cardiac electrical behavior, which is relatively immature, resembling fetal cardiomyocytes. Hallmarks of the immature phenotype include spontaneous beating, immature calcium handling, presence of developmental currents, and significant differences in the relative contributions of repolarizing potassium currents compared to adult ventricular myocyte [13][14][15].…”