Endocrine Abstracts

Introduction: Osteoprotegerin (OPG) and receptor activator for nuclear factor-κB ligand (RANKL) are cytokines that increase in cardiovascular diseases. Serum OPG levels are high in vascular calcifications, while RANKL is expressed by atherosclerotic lesions. The aim of the study was to assess the OPG and RANKL concentrations in patients with stable coronary artery disease.

Material and methods: The study included 38 patients diagnosed with ischemic coronary disease (16 men and 22 women, mean age 54.3±7.2 years) and 34 control subjects, sex and age-matched. Analyses for serum cholesterol, high and low-density lipoprotein (HDL and LDL) cholesterol, triglycerides, and glucose were performed by enzymatic methods. High-sensitivity C-reactive protein (hsCRP), OPG and RANKL were measured by ELISA.

Results: Serum OPG levels were significantly higher in study group than in controls (3.52±0.75 vs 1.19±0.35 pmol/l, P<0.0001). RANKL (pmol/l) to OPG (pmol/l) ratio was significantly higher in study cases than in controls (0.48±0.12 vs 0.30±0.12, P<0.0001). OPG values did not correlate with age, cholesterol, HDL-cholesterol, triglycerides and hsCRP. A significant correlation was found between RANKL and OPG: r=0.530, r²=0.281, P=0.003. RANKL/OPG correlated positively with total cholesterol (r=0.509, r²=0.295, P=0.004) and hsCRP values (r=0.453, r²=0.205, P=0.01), but it didn’t correlate with age, triglycerides and glucose. There were not significant differences between men and wome regarding: OPG, RANKL/OPG, hsCRP levels and lipid profile. Receiver-operating curve analysis showed that at a cutoff point of 0.381, RANKL/OPG presented a sensitivity of 86.2%, but a lower specificity (76.6%). At a cutoff point of 2.52 pmol/l, OPG showed a better sensitivity (91.2%) and specificity (89.1%). At a cutoff point of 2.95 mg/l, hsCRP presented a moderate sensitivity (79.3%), but a good specificity (93.1%).

Conclusion: Our study confirms that OPG and RANKL/OPG values are higher in ischemic patients, correlated with other inflammatory markers (hsCRP). RANKL/OPG could represent a good assessment and prediction parameter of future cardiac events.