Electrophysiological Characteristics of Human iPSC-Derived Cardiomyocytes for the Assessment of Drug-Induced Proarrhythmic Potential

<div><p>The aims of this study were to (1) characterize basic electrophysiological elements of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) that correspond to clinical properties such as QT-RR relationship, (2) determine the applicability of QT correction and analysis methods, and (3) determine if and how these in-vitro parameters could be used in risk assessment for adverse drug-induced effects such as Torsades de pointes (TdP). Field potential recordings were obtained from commercially available hiPSC-CMs using multi-electrode array (MEA) platform with and without ion channel antagonists in the recording solution. Under control conditions, MEA-measured interspike interval and field potential duration (FPD) ranged widely from 1049 to 1635 ms and from 334 to 527 ms, respectively and provided positive linear regression coefficients similar to native QT-RR plots obtained from human electrocardiogram (ECG) analyses in the ongoing cardiovascular-based Framingham Heart Study. Similar to minimizing the effect of heart rate on the QT interval, Fridericia’s and Bazett’s corrections reduced the influence of beat rate on hiPSC-CM FPD. In the presence of E-4031 and cisapride, inhibitors of the rapid delayed rectifier potassium current, hiPSC-CMs showed reverse use-dependent FPD prolongation. Categorical analysis, which is usually applied to clinical QT studies, was applicable to hiPSC-CMs for evaluating torsadogenic risks with FPD and/or corrected FPD. Together, this results of this study links hiPSC-CM electrophysiological endpoints to native ECG endpoints, demonstrates the appropriateness of clinical analytical practices as applied to hiPSC-CMs, and suggests that hiPSC-CMs are a reliable models for assessing the arrhythmogenic potential of drug candidates in human.</p></div

Relationship between field potential duration (FPD)/corrected FPD (FPDc) and interspike interval (ISI) of 96 samples of hiPSC-CM.

<p>The data in sham treatment from 4 facilities were plotted (n = 96) in Fig 2a (FPD-ISI), Fig 2b (FPDcF-ISI) and Fig 2c (FPDcB-ISI), respectively. The solid and dashed lines indicate the linear regression line and 95% confidence bands, respectively. The equation, R² value, and root mean squared prediction error (RMSE) are shown in the figures.</p

Assay design and representative field potential (FP) waveforms before/after drug application.

<p>Schematic depicting the measurement schedule for the hiPSC-CM/MEA assay (Fig 1a). The upper panels show FP waveforms and parameters, and the lower panels indicate the arrhythmogenic waveform of EAD (left, dashed circle) and TA (right, dashed circle) (Fig 1b). Example FP waveforms after application of DMSO, E-4031, cisapride or chromanol 293B (Fig 1c).</p

Effects of <i>I</i>_Kr and <i>I</i>_Ks inhibitors on field potential duration (FPD)-interspike interval (ISI) plots.

<p>FPD-ISI plots are shown before and after compound application both in terms of absolute values (left) and % change (right), for DMSO (Fig 3a), E-4031 (Fig 3b), cisapride (Fig 3c) and chromanol 293B (Fig 3d). The solid lines and dashed lines indicate the linear regression lines and 95% confidence bands, respectively. Data for the middle concentrations are omitted for clarity. ‘Slope’ refers to the slope of the regression line.</p

Categorical analyses of absolute FPD values after E-4031 application.

<p>Categorical analyses of absolute FPD values after E-4031 application.</p

Categorical analyses of absolute FPD values after cisapride application.

<p>Categorical analyses of absolute FPD values after cisapride application.</p