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.