Abstract
Electrifying Insights: How hiPSC-CM-MEA technology detects hidden cardiotoxic risks in pre-clinical screenings.
Background/Introduction: Cardiotoxicity is a major challenge in drug development, often leading to clinical trial failures and market withdrawals. Traditional preclinical models, including animal assays, frequently fail to predict human-specific electrophysiological responses. Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) combined with multi-electrode array (MEA) technology offer a more physiologically relevant platform for assessing compound-induced electrophysiological and proarrhythmic effects.
Purpose: This study assesses the predictive value of the hiPSC-CM-MEA assay in detecting drug-induced electrophysiological abnormalities, including field potential and contractility alterations, as well as arrhythmias, across acute and chronic exposure timepoints. Selected compounds were further investigated to determine their cytotoxic potential, and benchmark dose, while also elucidating their molecular mechanisms of action. These compounds, found in traditional Chinese medicine, the food and cosmetic industries, or under evaluation as anti-cancer drugs, may possess previously unrecognized cardiotoxic or therapeutic potential.
Methods: Commercial hiPSC-CMs were seeded in 24-well MEA plates and exposed to a single dose (1µM) of 320 phytochemicals. MEA recordings assessed FIELD POTENTIAL (Spike Amplitude, Field Potential Duration (FPD), Beat Period (BP), Beat Period Irregularities (BPI)) and CONTRACTILITY parameters (Beat Amplitude (BA), Excitation-Contraction Delay) at 30min, 2h (acute) and 24h, 48h (chronic) exposure timepoints. Validation was performed using known proarrhythmic compounds (e.g., E-4031, Bepridil). Cytotoxicity was evaluated via a live/dead fluorescence viability assay.
Results: The hiPSC-CM-MEA assay identified 38 compounds inducing significant (>2 StD) electrophysiological alterations. Two distinct ToxPi™ ranking models prioritized four inotropic compounds for screening in a 3D engineered heart tissue model while eleven proarrhythmic compounds were selected for further analysis of their effects on ion channel activity. Compounds causing prolonged FPD, BP, and increased BPI indicated proarrhythmic risk, while BA and BP changes identified inotropic effects. Notably, classic proarrhythmic drugs, scored high in the expected categories, confirming assay accuracy. Cytotoxicity analysis revealed six compounds with mild to severe effects after 72 hours, with no acute-phase toxicity observed.
Conclusion(s): The hiPSC-CM-MEA assay is a robust, human-relevant, mid-throughput tool for early cardiotoxicity screening. It enables higher-throughput, less labor-intensive analysis than patch-clamp assays while maintaining predictive accuracy. This first blinded large-scale phytochemical MEA screening integrates two ToxPi ranking models for precise classification of inotropic and proarrhythmic compounds. Positive control validation confirms reliability, supporting safer drug development while reducing reliance on animal models.