Modeling Atrial Fibrillation using Human Embryonic Stem Cell-Derived Atrial Tissue

Abstract

Since current experimental models of Atrial Fibrillation (AF) have significant limitations, we used human embryonic stem cells (hESCs) to generate an atrial-specific tissue model of AF for pharmacologic testing. We generated atrial-like cardiomyocytes (CMs) from hESCs which preferentially expressed atrial-specific genes, and had shorter action potential (AP) durations compared to ventricular-like CMs. We then generated confluent atrial-like CM sheets and interrogated them using optical mapping techniques. Atrial-like CM sheets (~1 cm in diameter) showed uniform AP propagation, and rapid re-entrant rotor patterns, as seen in AF could be induced. Anti-arrhythmic drugs were tested on single atrial-like CMs and cell sheets. Flecainide profoundly slowed upstroke velocity without affecting AP duration, leading to reduced conduction velocities (CVs), curvatures and cycle lengths of rotors, consistent with increased rotor organization and expansion. By contrast, consistent with block of rapid delayed rectifier K+ currents (Ikr) and AP prolongation in isolated atrial-like CMs, dofetilide prolonged APs and reduced cycle lengths of rotors in cell sheets without affecting CV. In conclusion, using our hESC-derived atrial CM preparations, we demonstrate that flecainide and dofetilide modulate reentrant arrhythmogenic rotor activation patterns in a manner that helps explain their efficacy in treating and preventing AF.

Generating ring-shaped engineered heart tissues from ventricular and atrial human pluripotent stem cell-derived cardiomyocytes

“…Moreover, despite improvements relative to previously described hPSC-derived tissue models, some important functional parameters such as the cells' resting membrane potential (which is relatively depolarized at~−60 mv), the measured conduction velocities, and the amplitudes of the mechanical forces generated still did not reach the same level of maturity as the adult heart. This early maturity state represents a general limitation in the hPSC-CMs field 68 , and similar results were observed in other hPSC-based EHT models 22,61 . This limitation may be ameliorated by ongoing efforts in the field to generate a more mature hPSC-CMs by using different hormonal treatments 69,70 , optimizing extracellular matrix composition 71 , mechanical and electrical training 28 , and a variety of other interventions 68 .…”

“…This cellular heterogeneity may significantly hamper the use of hPSC-CMs for many of the aforementioned applications. To address this challenge, significant efforts have been made recently to establish development biology-guided hPSC differentiation protocols and/or selection strategies in an attempt to generate purified populations of chamber-specific cardiomyocytes 8,10,[20][21][22][23] .…”

Deep phenotyping of human induced pluripotent stem cell–derived atrial and ventricular cardiomyocytes

“…differentiation appear less efficient than those for ventricular CMs, giving approximately 50%-65% cTNT + CMs (9,14), or apply a cocktail of cytokines and growth factors using the embryoid body method (10,14,15), which are cost-intensive and laborious. The phenotyping of the generated atrial and ventricular iPSC-CMs was mainly based on electrophysiological measurements and gene expression profiles of subtypespecific markers (16)(17)(18).…”

Human Induced Pluripotent Stem Cells Derived from a Cardiac Somatic Source: Insights for an In-Vitro Cardiomyocyte Platform

“…In both cases, E diast of derived-CMs hyperpolarizes and the activation of all expressed ion channels allows to develop an AP profile more similar to the one of atrial or ventricular adult CMs. This optimized physiological condition has been used to investigate mechanisms of cardiac cellular disease [4] and predict pharmacological approaches [5,6]. Overall, by adding I K1 (through dynamic clamp or channel overexpression), hiPSC-CMs AP becomes more similar to the adult one, suggesting that from the electrophysiological point of view the lack of this channel may be the main reason for the hiPSC-CM immaturity.…”

“…The possibility to differentiate them into functional cardiomyocytes (hiPSC-CMs) awakened excitement for the potential use of those cells in repairing and regenerating damaged cardiac tissue [2,3]; however, even though hiPSC-CMs represent an autologous source that overcomes the immunological limitations and ethical concerns belonging to embryonic stem cells (ESCs), the risk of tumor formation and uncontrolled differentiation have restricted this kind of approach. The possibility to characterize specific phenotypes associated with patient-specific genotypes allows the use of hiPSC-derived cells for disease modelling and drug development with very promising results [4][5][6].…”