Levels of amino acids and homoarginine in the venous basins of the brain and the heart muscle in patients with ischemic heart disease

Introduction. Under the conditions of circulatory disorders and coronary heart disease (CHD), amino acids acquire additional value as a source of intermediates of Krebs cycle, participating in cell energetics. If there is a disturbance of energy metabolism, the level of amino acids in the blood can change, including the minor non-encoding amino acid homoarginine (hArg).The objective of this study was to compare the shifts in the levels of hArg and other amino acids in the venous blood flowing from the tissues of the heart and brain versus their levels in blood plasma from the cubital vein in patients with CHD.Methods and materials. The study used plasma samples of 58 patients (46 men and 12 women) aged 62 (57 — 66) years with CHD and heart failure of functional class III (NYHA). The level of hArg and the spectrum of 22 other amino acids were determined by the reversed-phase high-performance liquid chromatography (HPLC). Besides, the levels of lactic acid (LA) were determined by spectrophotometric method, as well as routine biochemical parameters were determined using standard kits.Results. Patients with CHD had compensated, without significant deviations, biochemical data of glucose level, lipid and nitrogen metabolism profiles. The level of hArg in the patient group of 1.4 (1.0—1.9) p.M was significantly lower compared to the reference interval, and the level of total homocysteine was increased, although there were no differences depending on the venous basin. The highest concentrations of LA, alanine and glutamine were detected in the plasma from the internal jugular vein. At the same time, lower concentrations of arginine, lysine and alanine corresponded to the lowest values of hArg.Conclusion. In patients with CHD and heart failure, a significant increase in the levels of glutamine and alanine in plasma from the internal jugular vein and coronary sinus in comparison with plasma from the cubital vein was accompanied by profound dysregulation of energy metabolism with the decrease in hArg levels.