Beta-adrenoreactivity of erythrocyte membranes and expression of beta1-adrenergic receptors of cardiomyocytes in patients with heart failure with different left ventricular ejection fraction

Abstract

Introduction. More and more studies demonstrate the importance of determining the beta-adrenergic reactivity of erythrocyte membranes (beta-ARM) for predicting the severity of cardiovascular diseases, including chronic heart failure. But the presence of general patterns between the change in beta-ARM and the expression of beta1adrenergic receptors on the membranes of cardiomyocytes, depending on the left ventricular ejection fraction (LVEF) remains questionable.Aim: To evaluate beta-ARM and expression of beta1-adrenergic receptors of cardiomyocytes in groups of patients with heart failure with preserved (≥ 50%) and reduced (< 50%) LV EF.Materials and methods. The study included 100 patients with chronic heart failure of ischemic origin. Groups of 79 patients with LVEF ≥ 50% and 21 patients with LVEF < 50% were formed. The levels of epinephrine and norepinephrine in blood plasma and the expression of beta1-adrenergic receptors in myocardial samples were assessed using enzyme immunoassay. Beta-ARM was determined in whole blood by assessing the inhibition of hemolysis of erythrocytes placed in a hypoosmotic medium in the presence of a selective beta-blocker.Results. In the group with LV EF < 50%, beta-ARM was increased (p = 0.037), amounting to 31.9% (23.2; 40.1), compared with the group with LVEF ≥ 50%, where beta-ARM was 21.4% (15.0; 31.7). At the same time, in patients with LV EF < 50%, the expression of beta1-AR on cardiomyocyte membranes was significantly lower than in the other group (p = 0.037): 2.7 (2.1; 3.0) ng/mg and 3.1 (2.4; 3.9) ng/mg total protein, respectively. However, plasma levels of epinephrine and noradrenaline were comparable in the study groups.Conclusion. Patients with heart failure with LVEF < 50% were characterized by increased beta-ARM and reduced expression of beta1-AR on cardiomyocyte membranes compared with the group with LVEF ≥ 50% with comparable levels of circulating catecholamines.