Abstract Body: Background: Trimethylamine (TMA) is a gut-derived metabolite of choline and L-carnitine that is converted to trimethylamine N-oxide (TMAO) in the liver. Elevated plasma TMAO levels are strongly associated with an increased risk of cardiovascular disease. Previous studies suggest that TMA and TMAO promote inflammation, oxidative stress, and dysregulation of cholesterol metabolism, contributing to pro-atherosclerotic changes in blood vessels. We hypothesize that high levels of TMA and TMAO induce cardiac cell damage through oxidative stress and mitochondrial dysfunction.
Goals/Methods: This study utilizes H9c2 myoblast cells to investigate the effects of TMA and TMAO on cardiac cell function. Cells were treated with different concentrations of TMA or TMAO (0.001uM-500mM) to assess dose-dependent effects on cell viability using the colorimetric Cell Counting Kit-8. Additionally, mitochondrial membrane potential (MMP) and intracellular reactive oxygen species (ROS) levels were measured using MT-1 and DCFDA fluorescence assays, respectively. All data were presented as means ± SE. The data was analyzed by student t-test. p<0.05 are considered to be statistically significant.
Results: Higher concentrations (10-500 mM) of TMA or TMAO dose-dependently reduced cell viability. TMA (80 mM) significantly attenuated H9c2 cell viability to 25.3 ± 2.1% (n=8) compared to the control. In contrast, TMAO exerted similar effects (26.9 ± 7.3%, n=5) at a higher concentration (250 mM). The ROS levels remained unchanged in TMA-treated cells at 80 mM (104 ± 20.7%, n=3), whereas TMAO (250 mM) showed a 44.53 ± 0.78 fold increase in ROS production. Additionally, TMA (80 mM) slightly reduced MMP to 94.0 ± 5.1% (n=2), while TMAO (250 mM) significantly reduced MMP to 74.8 ± 2.8% (n=2).
Conclusion: The data suggest that higher doses of TMA and TMAO reduced H9c2 cell viability. In contrast to TMAO, TMA showed higher potency. TMAO-induced cell damage is mediated by increased ROS production and MMP reduction. However, TMA's mechanism of cell damage remains unclear, as ROS levels and MMP were not significantly altered. Further studies are needed to elucidate the precise mechanisms underlying TMA-mediated cytotoxicity.