Sohnis Research Laboratory for Cardiac Electrophysiology and Regenerative Medicine, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel.
First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim, University of Heidelberg, Mannheim, Germany; DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, Mannheim, Germany.
J Am Coll Cardiol. 2019 May 14;73(18):2310-2324. doi: 10.1016/j.jacc.2019.02.055.
The short QT syndrome (SQTS) is an inherited arrhythmogenic syndrome characterized by abnormal ion channel function, life-threatening arrhythmias, and sudden cardiac death.
The purpose of this study was to establish a patient-specific human-induced pluripotent stem cell (hiPSC) model of the SQTS, and to provide mechanistic insights into its pathophysiology and therapy.
Patient-specific hiPSCs were generated from a symptomatic SQTS patient carrying the N588K mutation in the KCNH2 gene, differentiated into cardiomyocytes, and compared with healthy and isogenic (established by CRISPR/Cas9-based mutation correction) control hiPSC-derived cardiomyocytes (hiPSC-CMs). Patch-clamp was used to evaluate action-potential (AP) and I current properties at the cellular level. Conduction and arrhythmogenesis were studied at the tissue level using confluent 2-dimensional hiPSC-derived cardiac cell sheets (hiPSC-CCSs) and optical mapping.
Intracellular recordings demonstrated shortened action-potential duration (APD) and abbreviated refractory period in the SQTS-hiPSC-CMs. Similarly, voltage- and AP-clamp recordings revealed increased I current density due to attenuated inactivation, primarily in the AP plateau phase. Optical mapping of the SQTS-hiPSC-CCSs revealed shortened APD, impaired APD-rate adaptation, abbreviated wavelength of excitation, and increased inducibility of sustained spiral waves. Phase-mapping analysis revealed accelerated and stabilized rotors manifested by increased rotor rotation frequency, increased rotor curvature, decreased core meandering, and increased rotor complexity. Application of quinidine and disopyramide, but not sotalol, normalized APD and suppressed arrhythmia induction.
A novel hiPSC-based model of the SQTS was established at both the cellular and tissue levels. This model recapitulated the disease phenotype in the culture dish and provided important mechanistic insights into arrhythmia mechanisms in the SQTS and its treatment.
短 QT 综合征（SQTS）是一种遗传性心律失常综合征，其特征为异常离子通道功能、危及生命的心律失常和心源性猝死。
本研究旨在建立 SQTS 的患者特异性人诱导多能干细胞（hiPSC）模型，并为其病理生理学和治疗提供机制见解。
从携带 KCNH2 基因 N588K 突变的有症状 SQTS 患者中生成患者特异性 hiPSC，分化为心肌细胞，并与健康和同基因（通过基于 CRISPR/Cas9 的突变校正建立）对照 hiPSC 衍生的心肌细胞（hiPSC-CMs）进行比较。通过膜片钳技术在细胞水平上评估动作电位（AP）和 I 电流特性。通过 2 维 hiPSC 衍生的心脏细胞片（hiPSC-CCSs）和光学标测在组织水平上研究传导和心律失常发生。
细胞内记录显示 SQTS-hiPSC-CMs 的动作电位时程（APD）缩短和不应期缩短。同样，电压和 AP 钳位记录显示 I 电流密度增加，主要是由于 AP 平台期的失活减弱。SQTS-hiPSC-CCSs 的光学标测显示 APD 缩短、APD 率适应受损、激发波长缩短以及持续螺旋波的诱导性增加。相位标测分析显示，旋转频率增加、旋转曲率增加、核心蜿蜒减少以及旋转复杂性增加，表明旋转速度加快且稳定。奎尼丁和双异丙吡胺的应用可使 APD 正常化并抑制心律失常的诱导，但索他洛尔则不然。
在细胞和组织水平上建立了 SQTS 的新型 hiPSC 模型。该模型在培养皿中再现了疾病表型，并为 SQTS 中的心律失常机制及其治疗提供了重要的机制见解。
