Clinical QTc/QRS prediction using hiPSC derived cardiomyocytes

QTc and QRS liabilities are a serious concern when developing novel clinical compounds. Assessment of ion channel activity provides a robust method to highlight potential risks, however it may not be sufficient to capture all potential mechanisms that could induce QTc, QRS or arrhythmia issues. In such cases an integrated system such as the hiPSC cardiomyocyte (hiPSC-CM) model can be a valuable model.

We can assess compounds for such liabilities in hiPSC-CMs in a higher throughput 96-well plate-based format. Using a voltage sensitive fluorescent dye, we can simultaneously measure action potential waveforms with high fidelity across all wells using the Lumencor Volta high frequency (10kHz) plate reader. This allows us to accurately capture endpoints such as action potential duration (e.g. APD₉₀), rise time and beat rate. Moreover, this system allows for the assessment of compounds over extended time periods (up to 72h) in serum free conditions.

A key aspect of this model is its ability predict a compounds propensity to generate a prolongation in the clinical QTc interval. Moreover, that assay can help predict the free clinical exposure of a novel compound that would be associated with a 10 ms change in clinical QTc. Similarly, this model can also define the probability of a QRS clinical liability.

Further reading: Characterization of a high throughput human stem cell cardiomyocyte assay to predict drug-induced changes in clinical electrocardiogram parameters, European Journal of Pharmacology, Volume 912, 2021.

iPSC-derived cardiomyocyte screening using conventional manual patch-clamp

Services to evaluate the effect of compounds on action potentials recorded from iPSC-derived cardiomyocytes using conventional manual patch clamp methodology are also provided. Spontaneous or evoked action potentials can be recorded and used to determine the effect of compounds on a range of action potential parameters. The recordings are stable for >30 minutes, which allows the cumulative application of multiple concentrations of each compound.

The manual patch clamp assay generates high fidelity recordings that allow the detection of even subtle changes to the action potential waveform. This helps to successfully discern between compounds with low, medium and high proarrhythmic risk profiles. For example, the figures below show mean data generated using 50 nM dofetilide, which reveals a significant prolongation of all measured APD values.

Chronic cardiotoxicity assay – hiPSC derived cardiomyocytes

Base impedance, an indicator of cell viability, can be used to non-invasively identify structural and functional cardiotoxicity over a chronic time course. We have developed a chronic cardiotoxicity assay using human iPSC-derived cardiomyocytes, which has been validated with a number of cardiotoxicants. For example, doxorubicin, a member of the anthracycline family that is used to treat breast cancer, is associated with a number of cardiac side effects, which includes acute atrial and ventricular arrhythmias, chronic cardiomyopathy and congestive heart failure. Our chronic cardiotoxicity assay recapitulates doxorubicin’s cardiotoxic effect by producing a concentration-dependent decrease of base impedance that develops following a 24 hour exposure period.

This protocol is designed to measure the potential for test compounds to become trapped inside the hERG channel pore, and it is the first to be validated on an automated patch clamp platform.

Cardiac safety screening resource library