Bone turnover imbalance in rheumatoid arthritis: Relationship between tumor necrosis factor- α and dickkopf-1 with bone turnover markers

Background: Rheumatoid arthritis (RA) is a chronic inflammatory disease that leads to bone loss due to an imbalance of the bone turnover process that could be evaluated using bone turnover markers. Inflammation in RA is mainly mediated by Tumor necrosis factor-α (TNF-α) that will increase osteoclastogenesis. In recent studies, Dickkopf-1 (DKK-1) is a key regulatory pathway for bone formation that affects osteoblastogenesis. Objective: This study aims to examine the imbalance of the bone turnover process in RA patients. Methods: This was a cross-sectional study with 38 subjects of premenopausal women with RA. Serum levels of TNF-α, DKK-1, and bone turnover markers (CTx and P1NP) were investigated. Result: The median duration of RA in this study was 5 years with 60.5% of subjects in remission or with low disease activity. The median value of TNF-α was 10.6 pg/mL, the mean value of DKK-1 was 4027pg/mL, the mean value of CTx was 2.74ng/mL, and the mean value of P1NP was 34pg/mL. This study revealed a weak positive correlation between TNF-α and P1NP (r=0.36; p=0.03). Conclusion: This study found a low level of TNF-α, a high level of DKK-1, a high level of CTx and a low level of P1NP that indicates an imbalance of bone turnover process in RA patients that is in favor of bone resorption.