Abstract 14097: High Throughput Calcium Transient Analysis for Early Stage Cardiotoxicity Testing in Cardiomyocytes Derived from Human Induced Pluripotent Stem Cells
Current High Throughput (HT) screening assays for cardio-active drugs and early phase cardiotoxicity testing rely on engineered tumor cell lines expressing a single ion channel which grossly underestimates the complexity of cardiomyocyte electrophysiology. Expensive and complex physiological tests performed in more appropriate model systems are reserved for late-stage development. To enable HT cardiotoxicity testing in relevant models, we have developed a Kinetic Image Cytometer (KIC) for high throughput dynamic imaging and automated cell-by-cell analysis of intracellular Ca2+ dynamics. Calcium is the final integrator of the electrical signals generated by the myriad of ion channels that contribute to the cardiomyocyte action potential (AP), therefore alterations in the AP will be reflected in the intracellular calcium transient. The KIC instrument electrically field-stimulates and records intracellular Fluo-4 fluorescence from hundreds of cardiomyocytes per well in the 96-well plate format. Additionally, post recording fixation and immunostaining of the cells can be performed allowing for biomarker expression levels to be directly correlated with the Ca2+ transient dynamics of individual cells. Here we report our application of the KIC to test a panel of 11 known cardio-active drugs (including activators and blockers of the Na+, hERG, IKs, and Ca2+ channels) on cardiomyocytes derived from human induced pluripotent stem cells. Here we demonstrate that alteration of channel activities leads to changes in the calcium transient dynamics, such as reduction in peak intensity, prolongation of the calcium transient, alterations in transient velocity, and the development of early after depolarizations. Our results suggest the sensitivity of calcium transient analysis via the KIC is on par with traditional electrophysiology techniques with the advantage of possessing a throughput that is several orders of magnitude higher than traditional techniques. This suggests that automated Ca2+ transient analysis could serve as an effective tool for eliminating compounds with potential cardio-active liabilities early on in the drug development cycle and preserving resources for the development of compounds with more favorable safety profiles.
- © 2011 by American Heart Association, Inc.