27.01.2021 | Webinar: Thinking outside the cardiac box
Patchliner and FLEXcyte 96 Webinar
Date: January 27. 2021
Dr. Elena Dragicevic (Senior Sales and Alliance Manager; Nanion Technologies)
Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are attractive due to their unlimited availability and human origin, making them a promising tool for cardiac research and safety pharmacology. However, they can show an immature phenotype such as lower inward rectifier potassium current (IK1), atypical expression pattern of ion channels, divergent response to pharmacological agents and contractile behaviour compared to adult CMs. Thus, their detailed characterization and optimized recording environments are essential.
We aimed to characterize and modulate electrophysiological and contractile properties of hiPSC-CMs using automated dynamic clamp and contraction measurements on flexible substrate.
Here, we recorded iCell Cardiomyocytes2 in voltage and current clamp using a combined automated patch clamp (APC) and dynamic clamp device (Patchliner Dynamite8), and contractility recordings were made using the FLEXcyte 96. During the APC recordings simulated IK1 and seal compensation were applied to up to 8 hiPSC-CMs simultaneously, while the contractility recordings were conducted in 96-well plates. We have tested various compounds targeting cardiac ion channels and recorded their effects on action potential duration (APD), sodium, calcium and potassium currents, as well as their effect on the contraction capabilities of these cells. Additionally, different levels of static and cyclic pressure were applied to the cell monolayers with the aim to induce membrane deflection for reproducibility test of Frank-Starling mechanism and to imitate the physiological stretching experienced by CMs in the beating human heart during systolic and diastolic phases, respectively.
Seal compensation and virtual IK1 in hiPSC-CMs resulted in more stable and longer APs with low APD variability. Consequently, the dynamic clamp approach enabled reliable calcium, sodium and potassium channel pharmacology on action potentials of these cells. Culturing conditions that support contractility, i.e. flexible membrane substrates, demonstrate Ca2+ channel pharmacology equivalent to that expected from adult CMs while applied mechanical stimulation resulted in functional changes of hiPSC-CMs physiology.