Spontaneous electrical activity of cardiomyocytes derived from hiPSCs of a patient with idiopathic ventricular fibrillation and RYR2 variant: impact of isoprenaline and varying concentrations of Ca2+

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Authors

KRÁL Martin ŠVECOVÁ Olga ZELENÁK Štefan PACHERNÍK Jiří BÁRTA Tomáš LIETAVA Samuel SYNKOVÁ Iva ZÍDKOVÁ Jana NOVOTNÝ Tomáš BÉBAROVÁ Markéta

Year of publication 2023
Type Conference abstract
MU Faculty or unit

Faculty of Medicine

Citation
Description Background: We have found a potentially proarrhythmic variant p. Y4734C in the ryanodine receptor type 2 (RYR2) in a patient suffering from idiopathic ventricular fibrillation. Here we bring pilot data showing the effect of 0.1 µM isoprenaline (ISO) and 0.5-5 mM Ca2+ on the spontaneous electrical activity of patient-specific cardiomyocytes derived from human-induced pluripotent stem cells (hiPSC-CM). Material and Methods: The spontaneous electrical activity of Y4734C-RYR2 hiPSC-CM (Y4734C) and hiPSC-CM of unrelated healthy control (WT) was recorded using the multielectrode array (MEA) technique at 37 °C. The cycle length (CL) and field potential duration (FPD and FPDc – correction according to Fridericia) are presented as the median ± interquartile range (IQR); non-parametric tests were used for comparison. Results: In control conditions (1.8 mM Ca2+), CL was insignificantly longer in WT (5.36±5.87 s; n=9) than in Y4734C (1.22±0.82 s; n=6). FDP and FPDc were significantly longer in WT (0.35±0.51 and 0.16±0.13 s, respectively; n=9) than in Y4734C (0.08±0.04 and 0.09±0.05 s, respectively; n=6; P?0.05). Under the effect of 0.1 µM ISO, CL was shortened by 45.0±16.7% (n=9, P?0.05) in WT and a similar, but insignificant change was observed in Y4734C (by 24.9±29.6%, n=5). We detected a significant CL prolongation in the presence of 1, 2, 3, and 5 mM Ca2+ in WT (P?0.05) whereas it was not significantly changed in Y4734C. No significant changes in FPD and FPDc were observed both in ISO and varying concentrations of Ca2+ except for a shortened FPD in 0.1 µM ISO in WT. Conclusions: The pilot data showed longer FPD and FPDc in WT vs. Y4734C and significant changes mostly in CL in WT at 0.1 µM ISO and various Ca2+ concentrations.
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