1 Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark.
2 Laboratory of Reproductive Biology, University Hospital of Copenhagen, Copenhagen, Denmark.
Stem Cells Dev. 2019 May 1;28(9):608-619. doi: 10.1089/scd.2018.0231. Epub 2019 Mar 26.
Cardiomyocytes (CMs) derived from human embryonic stem cells (hESCs) or induced pluripotent stem cells (iPSCs) are used to study cardiogenesis and mechanisms of heart disease, and are being used in methods for toxiological screening of drugs. The phenotype of stem-cell-derived CMs should ideally resemble native CMs. Here, we compare embryonic/fetal CMs with hESC-derived CMs according to function and morphology. CM clusters were obtained from human embryonic/fetal hearts from elective terminated pregnancies before gestational week 12, and separated into atrial and ventricular tissues. Specific markers for embryonic CMs and primary cilia were visualized using immunofluorescence microscopy analysis. Contracting human embryonic cardiomyocyte (hECM) clusters morphologically and phenotypically resemble CMs in the embryonic/fetal heart. In addition, the contracting hECM clusters expressed primary cilia similar to that of cells in the embryonic/fetal heart. The electrophysiological characteristics of atrial and ventricular CMs were established by recording action potentials (APs) using sharp electrodes. In contrast to ventricular APs, atrial APs displayed a marked early repolarization followed by a plateau phase. hESC-CMs displayed a continuum of AP shapes. In all embryonic/fetal clusters, both atrial and ventricular, AP duration was prolonged by exposure to the K11.1 channel inhibitor dofetilide (50 nM); however, the prolongation was not significant, possibly due to the relatively small number of experiments. This study provides novel information on APs and functional characteristics of atrial and ventricular CMs in first trimester hearts, and demonstrates that K11.1 channels play a functional role already at these early stages. These results provide information needed to validate methods being developed on the basis of in vitro-derived CMs from either hESC or iPSC, and although there was a good correlation between the morphology of the two types of CMs, differences in electrophysiological characteristics exist.
人心肌细胞（CMs）来源于人类胚胎干细胞（hESCs）或诱导多能干细胞（iPSCs），用于研究心脏发生和心脏病机制，并被用于药物毒理学筛选方法。干细胞衍生的 CMs 的表型理想情况下应类似于天然 CMs。在这里，我们根据功能和形态比较胚胎/胎儿 CMs 与 hESC 衍生的 CMs。CM 簇从妊娠 12 周前选择性终止妊娠的人胚胎/胎儿心脏中获得，并分离为心房和心室组织。使用免疫荧光显微镜分析观察胚胎 CM 的特异性标记物和初级纤毛。收缩的人心肌细胞（hECM）簇在形态和表型上与胚胎/胎儿心脏中的 CM 相似。此外，收缩的 hECM 簇表达的初级纤毛与胚胎/胎儿心脏中的细胞相似。通过使用尖锐电极记录动作电位（APs）来建立心房和心室 CM 的电生理特征。与心室 APs 相比，心房 APs 显示出明显的早期复极，随后是平台期。hESC-CMs 显示出 AP 形状的连续变化。在所有胚胎/胎儿簇中，包括心房和心室，AP 持续时间均通过暴露于 K11.1 通道抑制剂多非利特（50 nM）而延长；然而，延长并不显著，可能是由于实验数量相对较少。这项研究提供了关于在孕早期心脏中心房和心室 CM 的 APs 和功能特征的新信息，并表明 K11.1 通道在这些早期阶段已经发挥功能作用。这些结果为基于 hESC 或 iPSC 的体外衍生 CM 开发的方法提供了所需的验证信息，尽管两种类型的 CM 在形态上有很好的相关性，但在电生理特征上存在差异。
