Aggrecan Turnover in Women with Rheumatoid Arthritis Treated with TNF-α Inhibitors

This study was performed to evaluate the effects of 15-month anti-tumor necrosis factor α (anti-TNF-α) therapy on the aggrecan turnover of female rheumatoid arthritis (RA) patients. Serum was obtained from healthy subjects and female RA patients treated with TNF-α inhibitors (TNFαI) in combination with methotrexate. We measured serum levels of aggrecan chondroitin sulfate 846 epitope (CS846), aggrecan fragments (AGC), disintegrin and metalloproteinase with thrombospondin motifs-4 (ADAMTS-4) and 5 (ADAMTS-5), as well as their natural inhibitor, known as tissue inhibitor of matrix metalloproteinase-3 (TIMP-3), using immunoassay methods. Serum levels of CS846, AGC, ADAMTS-4, ADAMTS-5 and TIMP-3 were higher in female patients with RA before the treatment in comparison to healthy subjects. Ratio of ADAMTS-5 to TIMP-3 was significantly higher in RA women than in controls, whereas ADAMTS-4/TIMP-3 ratio did not differ from that in controls. During the anti-TNF-α therapy, the serum levels of 846 epitope increased, whereas levels of AGC decreased in female RA patients. Furthermore, 15 months of treatment with TNFαI downregulated serum levels of both ADAMTS, without any effect on TIMP-3 levels. These changes were accompanied by significantly reduced ratios of ADAMTS to TIMP-3. According to our results, anti-TNF-α therapy has a beneficial impact on aggrecan remodeling during RA.