Lymphocyte beta-adrenergic receptors in young subjects with peripheral or central obesity: relationship with central haemodynamics and left ventricular function

Abstract

This study was designed to evaluate total (t) and surface (s) beta-adrenergic receptor (BAR) density and their relationship with central haemodynamics and left ventricular function in young subjects with central or peripheral obesity. A total of 31 obese subjects (BMI > or = 30.5 kg.m-2 for males and > or = 27.3 kg.m-2 for females) aged less than 40 years and without other risk factors for cardiovascular diseases (smoking, hypertension, diabetes and lipid abnormalities) were studied. Nine had peripheral obesity and 22 central obesity according to WHR values; there were 20 lean controls (BMI < 25 kg.m-2 for males and < 24.7 kg.m-2 for females). Casual (c) and 24 h ambulatory mean blood pressures (MBP-24 h) were determined. BAR density was evaluated according to Böyum and De Blasi methods. Plasma catecholamines by high perfusion liquid chromatography and fasting immunoreactive plasma insulin (IRI) were also measured by RIA. Radionuclide angiocardiography was used to determine central haemodynamics and both systolic and diastolic left ventricular function. Total peripheral resistances (TPR) and intravascular volumes were also determined. Echocardiographic study was used to measure LVM, LVM.h-1, LVDD and IVS. Left ventricular ejection fraction (LVEF), peak filling rate (PFR), BARt and BARs were significantly lower (P < 0.05) and cardiac output, cardiac volumes, LVM, LVM. h-1 and time to PFR significantly higher (P < 0.05) in both obese groups than in lean controls. Plasma IRI was significantly (P < 0.05) higher in both obese groups whereas plasma norepinephrine was higher only in central obese.