Beat-to-Beat Variability in Field Potential Duration in Human Embryonic Stem Cell-Derived Cardiomyocyte Clusters for Assessment of Arrhythmogenic Risk, and a Case Study of Its Application

Abstract

We established a QT interval assessment system that uses human embryonic stem cell-derived cardiomyocyte clusters (hES-CMCs) in which the field potential duration (FPD) or corrected FPD (FPDc) was measured as an indicator of drug-induced QT interval prolongation. To investigate the applicability of the hES-CMC system to drug safety assessment, we investigated short-term variability in FPDc (STV FPDc ) (beat rate rhythmicity) as a marker of torsadogenic risk. We investigated the FPDc and STV FPDc of hES-CMCs treated with hERG channel blockers (E-4031 or cisapride) or with our proprietary compounds X, Y, and Z. We also evaluated the electrocardiograms and hemodynamics of dogs treated with compound X, Y, or Z. The torsadogenic hERG channel blockers increased STV FPDc and prolonged FPDc. Compounds X, Y, and Z had hERG inhibitory activity. Compound X prolonged FPDc with increased STV FPDc , whereas compounds Y and Z tended to shorten FPDc in the hES-CMC system. In the in vivo canine study, compound X prolonged corrected QT (QTc), and compounds Y and Z tended to shorten QTc, showing a good correlation with the results in hES-CMCs. These findings suggest that combined assessment of FPDc and STV FPDc in the hES-CMC system increases the predictability of torsadogenic risk.

Maturing human pluripotent stem cell-derived cardiomyocytes in human engineered cardiac tissues

“…For the hERG current, a half-maximal inhibitory concentration (IC 50 ) of 143 nM has been reported [207, 208]; and for the Ca v 1.2 channel, an IC 50 of 0.24–4.3μM has been reported [209–211] based on cell lines stably-transfected to express the respective human channel. In adult cardiac tissue (right atrial) an IC 50 of 123.0nM was reported based on the inotropic response subsequent to isoproterenol treatment [212].…”

“…Inhibition of I Kr results in a prolongation of the time between depolarization and repolarization [221], hence E-4031 affects APD. An IC 50 of 7–32nM was reported based on cell lines stably-transfected to express the human channel [208, 211]. hPSC-CMs have been demonstrated to be responsive to E-4031 with an IC 50 of 17nM [208, 214].…”

Use of Human Embryonic Stem Cell-Derived Cardiomyocyte Clusters to Assess Potential for Chronic Treatment with Compounds to Cause QT Prolongation

“…On the other hand, we did not expect that pentamidine at 10 µM would prolong FPDc at 24 h to a greater extent (62%) than did hERG channel blockage by cisapride at 100 nM (~20%). (The calculated IC 50 value of cisapride against hERG currents is 13.9 nM in hERG channel-overexpressing cells [20]). This unexpectedly long prolongation may have been caused by (as yet unknown) mechanisms other than inhibition of hERG trafficking by pentamidine.…”