Circulating osteoprotegerin is increased in the metabolic syndrome and associates with subclinical atherosclerosis and coronary arterial calcification

Context: The relationship between osteoprotegerin (OPG) a glycoprotein related to bone metabolism and the metabolic syndrome (MS) has not been established. Objective: The aim of this study is to evaluate OPG concentration in patients with MS and its association with subclinical atherosclerosis and coronary arterial calcification (CAC). Materials/methods: The study included 238 asymptomatic patients. MS was diagnosed according to the NCEP/ATPIII guidelines. OPG was measured by ELISA. All subjects underwent ultrasonography of the common carotid arteries to measure intima-media thickness (IMT) and evaluate the presence of atheroma plaques. In a subgroup (n = 39) CAC was quantified by ECG-triggered cardiac computed tomography. Adipose tissue was excised from 25 patients and OPG expression by RT-PCR and immunohistochemistry was studied. Results: Patients with the MS (n = 60) had higher OPG than patients without (n = 178) (p < 0.05). OPG correlated with IMT (r = 0.2, p = 0.005) and patients with atheroma plaques had higher OPG (p = 0.008) and also those with coronary artery calcification (p < 0.05). OPG expression was confirmed in adipose tissue (n = 12) and the expression was significantly higher in patients with MS than in those without (p = 0.003). Conclusions: This study shows that OPG may potentially be a biomarker for cardiovascular risk/damage in the MS and identifies adipose tissue as a potential source of OPG. (C) 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.