Purpose: Our aim was to determine the effects of infliximab on bone mineral metabolism in rheumatoid arthritis (RA) patients and analyze the relationship between inflammatory markers of acute phase thought to play a major role in bone remodeling.
Materials and methods: 36 patients with established RA were investigated. All patients underwent physical examination and blood and urinary analysis at baseline, 2 weeks, 14 weeks, 6 months and 12 months after the initiation of treatment. The serum levels of: tumor necrosis factor alpha (TNF-alpha), tumor necrosis factor alpha receptor 1 (TNFR1), TNFR2, interleukin 6 (IL-6), IL-17, IL-23 and markers of bone remodeling such as osteocalcin (BGP), deoxypyridynoline (Dpd), and N-telopeptide of type I collagen (NTx) were measured by ELISA.
Results: The results showed significant decrease of all the above cytokines levels in RA patients in comparison with those after 2 weeks of treatment. After 6 months, the markers of bone formation and resorption decreased compared to baseline values. We found positive correlation between the levels of NTx and the levels of IL-6, IL-17 and TNFR1, and between the levels of Dpd and IL-6 and Dpd and TNFR2, whereas negative correlation between BGP and IL-23. After 12 months the positive association was found at the BGP level and IL-6 as well as Dpd and the level of IL-6. We also observed a positive relation between Dpd and TNF-alpha and negative between BGP and TNFR1.
Conclusion: We suggest that infliximab treatment may limit the risk of osteoporosis in RA patients.