Effect of carvedilol on β-adrenoceptor density on peripheral lymphocytes from patients with chronic heart failure

Abstract

Objective To explore the effect of carvedilol on a-adrenoceptor density on peripheral lymphocytes from patients with chronic heart failure(CHF).Methods 112 CHF patients[New York Heart Association(NYHA) class Ⅱ ~Ⅳ) were randomly received either low dose carvedilol(12.5mg/d,n=56) or high dose carvedilol(50mg/d,n=56) for three months. Echocardiographic examinations were performed before and after drug administration. The maximum density of a-adrenoceptor( β max) on peripheral lymphocytes was measured by radioligand binding assay using 3H-dihydroalprenolol.Results The total study population consisted of 105 patients. The left ventricular end-diastolic dimension(LVEDD) and left ventricular end-systolic dimension(LVESD) were significantly decreased, the left ventricular ejection fraction(LVEF) was significantly increased after drug treatment. Compared with the low dose carvedilol group, the high dose carvedilol groun showed that LVEDD and LVESD were significantly decreased(P< 0.05), whereas LVEF significantly increased(P<0.01). The level of β max was much lower in those patients with more severe symptoms(NYHA class Ⅱ ~ Ⅴ). The level of β max was not significantly changed before and after drug treatment in the low dose carvedilol group, but was significantly decreased after drug treatment in the high dose carvedilol group(P < 0.05).Conclusion High dose carvedilol is more effective than low dose in attenuating left ventricular remodeling and in improving systolic function after heart failure. The beneficial effect of earvedilol is not depending on the change of β -adrenoceptor density. Key words: Heart failure ; β3-adrenoceptor ; Lymphocyte ; Carvedilol