Abstract 4630: Pro-Arrhythmic Effects of Lysolecithin on Isolated Cardiomyocytes
Aim The aim was to set up in vitro model for studies of arrhythmias in cardiomyocytes and to test whether lysolecithin (LLC) - a hydrolytic product of ischemia-caused degradation of membrane phospholipids - would cause arrhythmia.
Methods HL-1 cells (immortalized mouse cardiomyocytes), n=15, were cultured in standard medium on the MEA chips (Multi Channel Systems, Reutlingen, Germany) for 4 –7 days until spontaneous beating activity was observed. The chip consists of sixty 30 μm electrodes connected through an amplifier to the computerized system. Various doses of isoprenaline (10–20 μM) and LLC (1–40 μM) were added to the cell cultures. After incubation-time of 5 minutes the recordings of electrical activity, i.e. field potentials (FP- equivalent of QRS-T complex), were made for up to 2 minutes. Analysis of FP rise-time (FPRT), field potential duration (FPD), frequency of spontaneous activity and occurrence of arrhythmia was performed.
Results Stimulation with isoprenaline caused non-significant changes in FPRT and FPD. The frequency increased moderately by 17 % (p < 0.05) and the rhythm was stable apart from infrequent extrasystoles. Stimulation with LLC increased both FPRT and FPD (both p < 0.05) and there was a pronounce alteration in the morphology of the FPs. Furthermore, in 83% of the cell cultures, irregular activation patterns were seen (typical of fibrillatory activity) while the mean frequency decreased.
Discussion This simple in vitro model can reproducibly induce a fibrillation-like arrhythmia in isolated cardiomyocytes after the treatment with the potent pro-arrhythmic agent LLC and can be useful for screening studies of potential anti-arrhythmic drugs.