Gizurarson Sigfus, Shao Yangzhen, Miljanovic Azra, Råmunddal Truls, Borén Jan, Bergfeldt Lennart, Omerovic Elmir
Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg, Bruna stråket 16, Gothenburg, Sweden.
Cell Physiol Biochem. 2012;30(2):477-88. doi: 10.1159/000339029. Epub 2012 Jul 10.
Sudden death due to malignant ventricular arrhythmias is the most important cause of death in acute myocardial infarction. Improved knowledge about the pathophysiology underlying these arrhythmias is essential in the search for new anti-arrhythmic strategies. Lysophosphatidylcholine (LPC), a hydrolysis product of (membrane) phospholipid degradation, is one of the most potent pro-arrhythmic substances that accumulate in the human heart during myocardial ischemia. The aim of this study was to set up and validate an in vitro experimental system for studies on the effects of LPC on electrophysiological parameters in beating cardiomyocytes.
Spontaneously beating HL-1 cardiomyocytes were cultured on multielectrode array microchips for three days for the recording of electrical activities in the form of field potentials (FP). FPs were recorded at baseline and after addition of 2, 4, 8, 12, 16, 20, and 24 µM of LPC to the cell medium (n=9). We found that LPC could induce rapid effects on electrical parameters in the HL-1 cells. The overall half-maximal effective concentration (EC(50)) of LPC was around 12 µM. The beating rate and peak-peak amplitude of FP thus decreased at concentrations ≥ 12 µM and were inversely proportional to increased LPC concentration. The duration of FP was significantly prolonged with LPC above 12 µM and was concentration-dependent. LPC delayed signal propagation, an effect which was mimicked by blocking gap junctions with heptanol and attenuated by pre-treatment with isoprenaline and atropine. Finally, asynchronous activity was induced by LPC at >12 µM.
LPC induced prompt and pronounced electrophysiological alterations that may underlie its observed pro-arrhythmic properties. Our in vitro model with HL-1 cells and microelectrode array system may be a useful tool for preclinical studies of electrophysiological effects of various pathophysiological concepts.
恶性室性心律失常导致的猝死是急性心肌梗死最重要的死亡原因。深入了解这些心律失常的病理生理学对于寻找新的抗心律失常策略至关重要。溶血磷脂酰胆碱（LPC）是（膜）磷脂降解的水解产物，是心肌缺血时在人心脏中积聚的最有效的促心律失常物质之一。本研究的目的是建立并验证一个体外实验系统，用于研究LPC对跳动心肌细胞电生理参数的影响。
将自发跳动的HL-1心肌细胞在多电极阵列微芯片上培养三天，以记录场电位（FP）形式的电活动。在基线时以及向细胞培养基中添加2、4、8、12、16、20和24 μM的LPC后记录FP（n = 9）。我们发现LPC可对HL-1细胞的电参数产生快速影响。LPC的总体半数有效浓度（EC50）约为12 μM。因此，当浓度≥12 μM时，FP的跳动频率和峰峰值幅度降低，且与LPC浓度升高呈反比。当LPC浓度高于12 μM时，FP的持续时间显著延长且呈浓度依赖性。LPC延迟信号传导，用庚醇阻断缝隙连接可模拟该效应，而异丙肾上腺素和阿托品预处理可减弱该效应。最后，当LPC浓度>12 μM时可诱导异步活动。
LPC可诱导迅速且明显的电生理改变，这可能是其观察到的促心律失常特性的基础。我们的HL-1细胞体外模型和微电极阵列系统可能是用于各种病理生理学概念电生理效应临床前研究的有用工具。
