Trimethyl-L‑lysine, the metabolic precursor of carnitine, and methylated derivatives of arginine in patients with cardiovascular diseases

Abstract

Objective of the present study was to estimate the concentrations of methylated derivatives of L‑lysine and L‑arginine in patients with blood circulation disorders. Design and methods. We examined plasma samples of 151 patients with cardiovascular diseases, including 86 patients with aortic aneurysm and 47 with aortic stenosis, as well as normal subjects divided in two age groups. The concentrations of trimethyl-L‑lysine (TML), symmetric dimethyl-L‑arginine (SDMA) and asymmetric dimethyl-L‑arginine (ADMA) were determined by liquid chromatography after solid phase extraction. Results. Decreased TML level was found in all patients, regardless of diagnosis, but there was an increase in ADMA and SDMA concentrations in comparison to healthy individuals (p < 0,001). These changes were accompanied by an increase in the concentration of lactic acid. TML decline was lower in the subgroup of patients with aortic stenosis compared to the subgroup with aortic aneurysm (p < 0,05), and there was no difference in lactate/pyruvate ratio and homocysteine level compared to healthy people. No significant correlations between TML and ADMA, TML and SDMA were found. Conclusions. Patients with different cardiovascular disorders demonstrate an altered level of markers of mitochondrial and endothelial dysfunction. Determination of blood TML level allows monitoring of protein methylation in the body. Being a precursor of carnitine, TML may characterize the changes in fatty acids transport relating to mitochondrial dysfunction development.