Human iPSC-Derived Cardiomyocytes for Investigation of Disease Mechanisms and Therapeutic Strategies in Inherited Arrhythmia Syndromes: Strengths and Limitations

Abstract

During the last two decades, significant progress has been made in the identification of genetic defects underlying inherited arrhythmia syndromes, which has provided some clinical benefit through elucidation of gene-specific arrhythmia triggers and treatment. However, for most arrhythmia syndromes, clinical management is hindered by insufficient knowledge of the functional consequences of the mutation in question, the pro-arrhythmic mechanisms involved, and hence the most optimal treatment strategy. Moreover, disease expressivity and sensitivity to therapeutic interventions often varies between mutations and/or patients, underlining the need for more individualized strategies. The development of the induced pluripotent stem cell (iPSC) technology now provides the opportunity for generating iPSC-derived cardiomyocytes (CMs) from human material (hiPSC-CMs), enabling patient- and/or mutation-specific investigations. These hiPSC-CMs may furthermore be employed for identification and assessment of novel therapeutic strategies for arrhythmia syndromes. However, due to their relative immaturity, hiPSC-CMs also display a number of essential differences as compared to adult human CMs, and hence there are certain limitations in their use. We here review the electrophysiological characteristics of hiPSC-CMs, their use for investigating inherited arrhythmia syndromes, and their applicability for identification and assessment of (novel) anti-arrhythmic treatment strategies.

Keywords: Arrhythmias; Cardiomyocytes; Human; Induced pluripotent stem cells; Pharmacology.

Fig. 1

Morphological and electrophysiological phenotype of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and native human ventricular cardiomyocytes (CMs). a Morphological differences between human adult ventricular CMs and hiPSC-CMs; note the different scale. b Examples of action potential (solid line) and calcium transient (dashed line) in human adult ventricular CMs and hiPSC-CMs (upper panels), and schematic representation of the time course and magnitude of relevant ion currents (lower panels). Figure modified from [68] (a) and [15] (b)

Fig. 2

Examples of techniques used for electrophysiological measurements in hiPSC-CMs. a hiPSC-CMs patched with manual anpatch clamp technique (upper panel). Typical AP trace recorded in hiPSC-CMs with the use of the patch clamp technique (lower panel). b Cluster of hiPSC-CMs seeded on multi-electrode arrays (MEAs) (upper panel). Field potential trace obtained with MEAs (lower panel). Assessable parameters are indicated in the corresponding figures. APD ₂₀, APD ₅₀, and APD ₉₀ action potential duration at 20, 50, and 90% repolarization; APA _max maximal AP amplitude; RMP resting membrane potential; MDP maximal diastolic potential; dV/dt _max maximal upstroke velocity; FPD field potential duration. Upper panel reproduced from [122]

Fig. 3

Effect of I _K1 injection on maximal diastolic potential (MDP) and maximal upstroke velocity (dV/dt _max) in hiPSC-CMs. a Representative example of action potential traces recorded from hiPSC-CMs upon injection of increasing magnitudes of simulated I _K1 using dynamic clamp. Impact of I _K1 injection at different amplitudes on MDP and dV/dt_max is shown in panels b and c, respectively (*p < 0.05). Figure reproduced from [68]

Fig. 4

Effect of the hERG allosteric modulator LUF7346 on field potential (FP) and action potential (AP) duration in LQT2 hiPSC-CMs. a Representative FP traces showing the effect of increasing concentrations of LUF7346 on FP duration measured in LQT2 hiPSC-CMs carrying the N996I mutation (LQT2^N996I). b Representative AP traces from LQT2^N996I hiPSC-CMs under baseline conditions (Tyrode) and after application of increasing concentrations of LUF7346 (color-code panels are shown in the insets). LUF7346 reduced FP and AP duration in LQT2^N996I hiPSC-CMs. Figure modified from [14]

Fig. 5

Comparable effect of the late sodium current blocker GS967 in SCN5A-1795insD^+/− hiPSC-CMs and Scn5a-1798insD^+/− murine cardiomyocytes. a, b Representative action potential (AP) traces (left panel) and average data for AP duration at 90% repolarization (APD₉₀, right panel) in SCN5A-1795insD^+/− hiPSC-CMs (a) and in Scn5a-1798insD^+/− cardiomyocytes (b) before and after application of GS967. GS967 was able to reduce AP duration in both models. *p < 0.05. Reproduced from [37], with permission

Fig. 6

Electrophysiological characteristics of a homozygous mutation in TECRL, the gene encoding for the trans-2,3-enoyl-CoA reductase like protein. a Example of ventricular tachycardia recorded by the implantable cardioverter defibrillator (ICD) in a patient carrying the homozygous splice site mutation c.331+1G>A in TECRL. b, c Representative calcium transient (b) and action potential (c) traces recorded in control (CTRL), heterozygous (HET), and homozygous (HOM) hiPSC-CMs carrying the TECRL mutation c.331+1G>A. The mutation causes a significant increase in diastolic calcium concentrations (b) and prolongation of action potential duration (c). d Addition of 5 μM flecainide (Flec) decreased the susceptibility to triggered activity in HOM hiPSC-CMs challenged with noradrenaline (NA). Reproduced from [79]