Arrhythmogenicity Test Based on a Human-Induced Pluripotent Stem Cell (iPSC)-Derived Cardiomyocyte Layer

Area of Science:

• Cardiology
• Stem Cell Biology
• Pharmacology

Background:

• In vitro drug screening using human-induced pluripotent stem-cell-derived cardiomyocytes (hiPSC-CMs) is advancing pharmaceutical safety assessments.
• Current methods, including screening for drug-induced prolonged QT interval, are recommended by ICH but require mechanistic insights into arrhythmogenicity.
• A comprehensive tissue-based test is needed to accurately assess the proarrhythmic potential of drugs.

Purpose of the Study:

• To develop and validate a tissue-based assay for measuring arrhythmogenicity using hiPSC-CMs.
• To investigate the mechanism of drug-induced arrhythmias, specifically reentry.
• To assess the utility of the assay for predicting drug effectiveness and individual cardiovascular disease risk.

Main Methods:

• hiPSC-CMs were differentiated and characterized using immunocytochemistry and patch-clamp techniques.
• A standard obstacle was introduced in the CM monolayer to induce reentry.
• Optical mapping was employed to measure arrhythmogenicity, defined as the probability of reentry occurrence at specific stimulation frequencies.

Main Results:

• The assay successfully demonstrated a change in potassium current, consistent with LQTS type 2, at high heart rates.
• Arrhythmogenicity was quantitatively measured based on reentry probability.
• The method showed potential for quantifying drug efficacy/inefficacy and determining donor-specific cardiovascular disease risk.

Conclusions:

• A novel hiPSC-CM based tissue assay provides a comprehensive platform for assessing drug-induced arrhythmogenicity.
• The assay elucidates mechanisms of arrhythmia, such as reentry, and can predict proarrhythmic drug effects.
• This approach holds promise for personalized medicine by assessing individual cardiovascular disease risk and drug response.