Objective: To investigate the relationship between the plasma osteoprotegerin (OPG) level and endothelium-dependent arterial dilation in type 1 diabetic patients.
Methods: Sandwich ELISA method was used to detect the plasma OPG levels of 22 newly diagnosed type 1 diabetic patients before and 6 months after treatment and of 28 healthy subjects. All patients were then given insulin therapy for 6 months. High resolution ultrasound was used to measure the brachial artery diameter at rest, after reactive hyperemia and after sublingual administration of glyceryltrinitrate (GTN).
Results: The plasma OPG level of the patients before treatment was 3.09 ng/L +/- 0.70 ng/L, significantly higher than that of the healthy controls (2.07 ng/L +/- 0.75 ng/L, P < 0.001). After 6 months treatment, the OPG level of the patients decreased to 2.58 ng/L +/- 0.59 ng/L, significantly lower than that before treatment (P < 0.001). The flow-mediated endothelium-dependent arterial dilation in the patients before treatment was 3.35% +/- 0.67%, significantly lower than that of the healthy controls (5.17% +/- 0.83%, P < 0.001), and was increased to 4.27% +/- 0.63% after 6 months treatment, significantly higher than that before (P < 0.001). Multivariate analysis showed that OPG level was significantly associated with endothelium-dependent arterial dilation, fasting blood glucose (FBG), hemoglobin A1c (HbA1c), and ultra-sensitive C-reactive protein (CRP) at baseline (all P < 0.01). The absolute change in OPG level was significantly correlation with the changes in endothelium-dependent arterial dilation, FBG, HbA1c, and CRP in the diabetic patients during the course of treatment (all P < 0.01).
Conclusion: Plasma OPG level is elevated in newly diagnosed diabetic patients, and the plasma OPG level is significantly associated with endothelial function.