Novel method for action potential measurements from intact cardiac monolayers with multiwell microelectrode array technology.

The cardiac action potential (AP) is vital for understanding healthy and diseased cardiac biology and drug safety testing. However, techniques for high throughput cardiac AP measurements have been limited. Here, we introduce a novel technique for reliably increasing the coupling of cardiomyocyte syncytium to planar multiwell microelectrode arrays, resulting in a stable, label-free local extracellular action potential (LEAP). We characterized the reliability and stability of LEAP, its relationship to the field potential, and its efficacy for quantifying AP morphology of human induced pluripotent stem cell derived and primary rodent cardiomyocytes. Rise time, action potential duration, beat period, and triangulation were used to quantify compound responses and AP morphology changes induced by genetic modification. LEAP is the first high throughput, non-invasive, label-free, stable method to capture AP morphology from an intact cardiomyocyte syncytium. LEAP can accelerate our understanding of stem cell models, while improving the automation and accuracy of drug testing.

Cross-Site Reliability of Human Induced Pluripotent stem cell-derived Cardiomyocyte Based Safety Assays Using Microelectrode Arrays: Results from a Blinded CiPA Pilot Study.

Recent in vitro cardiac safety studies demonstrate the ability of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) to detect electrophysiologic effects of drugs. However, variability contributed by unique approaches, procedures, cell lines, and reagents across laboratories makes comparisons of results difficult, leading to uncertainty about the role of hiPSC-CMs in defining proarrhythmic risk in drug discovery and regulatory submissions. A blinded pilot study was conducted to evaluate the electrophysiologic effects of 8 well-characterized drugs on 4 cardiomyocyte lines using a standardized protocol across 3 microelectrode array platforms (18 individual studies). Drugs were selected to define assay sensitivity of prominent repolarizing currents (E-4031 for IKr, JNJ303 for IKs) and depolarizing currents (nifedipine for ICaL, mexiletine for INa) as well as drugs affecting multichannel block (flecainide, moxifloxacin, quinidine, and ranolazine). Inclusion criteria for final analysis was based on demonstrated sensitivity to IKr block (20% prolongation with E-4031) and L-type calcium current block (20% shortening with nifedipine). Despite differences in baseline characteristics across cardiomyocyte lines, multiple sites, and instrument platforms, 10 of 18 studies demonstrated adequate sensitivity to IKr block with E-4031 and ICaL block with nifedipine for inclusion in the final analysis. Concentration-dependent effects on repolarization were observed with this qualified data set consistent with known ionic mechanisms of single and multichannel blocking drugs. hiPSC-CMs can detect repolarization effects elicited by single and multichannel blocking drugs after defining pharmacologic sensitivity to IKr and ICaL block, supporting further validation efforts using hiPSC-CMs for cardiac safety studies.

Multielectrode Array (MEA) Assay for Profiling Electrophysiological Drug Effects in Human Stem Cell-Derived Cardiomyocytes.

More relevant and reliable preclinical cardiotoxicity tests are required to improve drug safety and reduce the cost of drug development. Human stem cell-derived cardiomyocytes (hSC-CMs) provide a potential model for the development of superior assays for preclinical drug safety screening. One such hSC-CM assay that has shown significant potential for enabling more predictive drug cardiac risk assessment is the MEA assay. The Multi-electrode Array (MEA) assay is an electrophysiology-based technique that uses microelectrodes embedded in the culture surface of each well to measure fluctuations in extracellular field potential (FP) generated from spontaneously beating hSC-CMs. Perturbations to the recorded FP waveform can be used as an unbiased method of predicting the identity of ion channel(s) impacted on drug exposure. Here, a higher throughput MEA assay using hSC-CMs in 48-well MEA plates is described for profiling compound-induced effects on cardiomyocyte electrophysiology. Techniques for preparing hSC-CM monolayers in MEA plates and methods to contextualize MEA assay experimental results are also covered. © 2016 by John Wiley & Sons, Inc.

Comprehensive in vitro Proarrhythmia Assay (CiPA): Pending issues for successful validation and implementation.

INTRODUCTION: The Comprehensive in vitro Proarrhythmia Assay (CiPA) is a nonclinical Safety Pharmacology paradigm for discovering electrophysiological mechanisms that are likely to confer proarrhythmic liability to drug candidates intended for human use. TOPICS COVERED: Key talks delivered at the 'CiPA on my mind' session, held during the 2015 Annual Meeting of the Safety Pharmacology Society (SPS), are summarized. Issues and potential solutions relating to crucial constituents [e.g., biological materials (ion channels and pluripotent stem cell-derived cardiomyocytes), study platforms, drug solutions, and data analysis] of CiPA core assays are critically examined. DISCUSSION: In order to advance the CiPA paradigm from the current testing and validation stages to a research and regulatory drug development strategy, systematic guidance by CiPA stakeholders is necessary to expedite solutions to pending and newly arising issues. Once a study protocol is proved to yield robust and reproducible results within and across laboratories, it can be implemented as qualified regulatory procedure.

The prospective IQ-CSRC trial: A prototype early clinical proarrhythmia assessment investigation for replacing the ICH E14 thorough QTc (TQT) study.

INTRODUCTION: Early clinical Phase I ECG investigations designed to replace the currently applied thorough QT (TQT) study are reviewed to examine how they could complement and verify the conclusions of nonclinical investigations and, in particular, the Comprehensive in vitro Proarrhythmia Assay (CiPA). TOPICS: The IQ-CSRC trial is a prospective ascending multiple-dose first in human (FIH) type investigation performed as a possible replacement for the thorough QT study (TQT). Designed in accordance with the results of a simulation study by the FDA QT Interdisciplinary Review Team (IRT), it succeeded in correctly categorizing 5/5 established QTc-prolonging agents free of notable heart rate effects (dofetilide, dolasetron, moxifloxacin, ondansetron, and quinine) and the QTc-negative drug, levocetirizine. DISCUSSION: The positive results obtained with the IQ-CSRC study require additional confirmation with threshold QTc-positive and negative drugs and established QTc prolongers producing both increases and decreases in heart rate. In the future, similar studies should also adopt and validate innovative proarrhythmic metrics, in addition to, or instead of, the traditional proarrhythmic surrogate of QTc, to assess the proarrhythmic safety of candidate drugs.

Bridging Functional and Structural Cardiotoxicity Assays Using Human Embryonic Stem Cell-Derived Cardiomyocytes for a More Comprehensive Risk Assessment.

More relevant and reliable preclinical cardiotoxicity tests are required to improve drug safety and reduce the cost of drug development. Current in vitro testing strategies predominantly take the form of functional assays to predict the potential for drug-induced ECG abnormalities in vivo. Cardiotoxicity can also be structural in nature, so a full and efficient assessment of cardiac liabilities for new chemical entities should account for both these phenomena. As well as providing a more appropriate nonclinical model for in vitro cardiotoxicity testing, human stem cell-derived cardiomyocytes offer an integrated system to study drug impact on cardiomyocyte structure as well as function. Employing human embryonic stem cell-derived cardiacmyocytes (hESC-CMs) on 3 assay platforms with complementary insights into cardiac biology (multielectrode array assay, electrophysiology; impedance assay, cell movement/beating; and high content analysis assay, subcellular structure) we profiled a panel of 13 drugs with well characterized cardiac liabilities (Amiodarone, Aspirin, Astemizole, Axitinib, AZT, Bepridil, Doxorubicin, E-4031, Mexiletine, Rosiglitazone, Sunitinib, Sibutramine, and Verapamil). Our data show good correlations with previous studies and reported clinical observations. Using multiparameter phenotypic profiling techniques we demonstrate the dynamic relationship that exists between functional and structural toxicity, and the benefits of this more holistic approach to risk assessment. We conclude by showing for the first time how the advent of transparent MEA plate technology enables functional and structural cardiotoxic responses to be recorded from the same cell population. This approach more directly links changes in morphology of the hESC-CMs with recorded electrophysiology signatures, offering even greater insight into the wide range of potential drug impacts on cardiac physiology, with a throughput that is more amenable to early drug discovery.

High-throughput multi-parameter profiling of electrophysiological drug effects in human embryonic stem cell derived cardiomyocytes using multi-electrode arrays.

Human stem cell derived cardiomyocytes (hESC-CM) provide a potential model for development of improved assays for pre-clinical predictive drug safety screening. We have used multi-electrode array (MEA) analysis of hESC-CM to generate multi-parameter data to profile drug impact on cardiomyocyte electrophysiology using a panel of 21 compounds active against key cardiac ion channels. Our study is the first to apply multi-parameter phenotypic profiling and clustering techniques commonly used for high-content imaging and microarray data to the analysis of electrophysiology data obtained by MEA analysis. Our data show good correlations with previous studies in stem cell derived cardiomyocytes and demonstrate improved specificity in compound risk assignment over convention single-parametric approaches. These analyses indicate great potential for multi-parameter MEA data acquired from hESC-CM to enable drug electrophysiological liabilities to be assessed in pre-clinical cardiotoxicity assays, facilitating informed decision making and liability management at the optimum point in drug development.