Association of serum Dkk-1 levels with β-catenin in patients with postmenopausal osteoporosis

Wnt signaling plays an important role in the bone development and remodeling. The Wnt antagonist Dkk-1 is a potent inhibitor of bone formation. The aims of this study were firstly to compare the serum Dkk-1 levels in postmenopausal osteoporosis patients with age-matched healthy controls, and secondly, to assess the possible relationship between Dkk-1 and β-catenin, sclerostin, or bone turnover markers [CTX, PINP, N-MID-OT and 25(OH)D] in the setting of postmenopausal osteoporosis. A total of 350 patients with postmenopausal osteoporosis and 150 age-matched healthy controls were enrolled, and the serum levels of Dkk-1, β-catenin, sclerostin, OPG, and RANKL were detected by ELISA, and bone turnover markers [CTX, PINP, N-MID-OT and 25(OH)D] were measured by Roche electrochemiluminescence system in two groups. Serum Dkk-1 levels were significantly higher in postmenopausal osteoporosis group than in control group (P<0.001). Univariate analyses revealed that serum Dkk-1 levels were weakly negatively correlated to β-catenin (r=−0.161, P=0.003) and OPG (r=−0.106, P=0.047), while multiple regression analysis showed a negative correlation between serum Dkk-1 levels with β-catenin (β=−0.165, P=0.009) and BMD (β=−0.139, P=0.027), and a positive correlation between serum Dkk-1 levels and CTX (β=0.122, P=0.040) in postmenopausal osteoporosis group. No similar correlations ware observed in control group. The results provided evidence for the role of Dkk-1 in bone metabolism and demonstrated the link of Dkk-1 and Wnt/β-catenin in some ways.