Journal of Physical Chemistry & Biophysics
Open Access

Abstract

Novel Automated Patch-clamp Assays on Stem Cell-derived Cardiomyocytes: Will they Standardize In Vitro Pharmacology and Arrhythmia Research?

Amuzescu B, Scheel O and Knott T

Recent progress in embryonic stem cell and human induced pluripotent stem cell technology allowed effective generation of cultured cardiomyocyte preparations with over 99% purity, rendering them suitable for automated patchclamp approaches. Compared to current high-throughput drug screening methods, such as fluorescence assays using calcium-sensitive or transmembrane potential-sensitive dyes, or field potential recordings and activation mapping using multi-electrode arrays, patch-clamp experiments offer the possibility to combine action potential recordings in current-clamp mode with detailed characterization of drug effects on multiple ion current components with carefully designed voltage-clamp protocols, leading to an in-depth understanding of arrhythmogenesis conditions and mechanisms, especially when combined with cellular electrophysiology computerized models. The recently issued Comprehensive in vitro ProArrhythmia Assay (CiPA) guidelines emphasize the importance of pharmacological tests on multiple cardiac ion channels, including at least Nav1.5 (early and late), Cav1.2, hERG1, Kv7.1/minK, and Kir2.1, via voltage-clamp protocols, instead of simple hERG screening, combined with computer modeling, in order to determine the proarrhythmic liability of a drug candidate. In addition, patch-clamp assays on patient-specific induced pluripotent stem cell-derived cardiomyocytes will enhance current molecular diagnosis methods in cardiac channelopathies by identification of the faulty current component and individualized screening of drug sensitivity of mutant channels, a step forward for personalized medicine approaches.