Etanercept reduces the oxidative stress marker levels in patients with rheumatoid arthritis

This study was performed to evaluate the effects of the TNF-α inhibitor etanercept on oxidation stress markers representing DNA damage, lipid peroxidation, and protein glycosylation. Twenty-two rheumatoid arthritis (RA) patients underwent etanercept treatment. The levels of serum total, urinary total, and urinary free pentosidine, which is an advanced glycation end-product (AGE), of urinary N^ε-hexanoyl lysine (N^ε-HEL), and of 8-hydroxy-deoxy guanosine (8-OHdG) were measured at baseline and at 3 and 6 months after the initial treatment with etanercept. Serum total and urinary total pentosidine levels were reduced at 6 months after the initial treatment with etanercept, and urinary free pentosidine levels were reduced at 3 and 6 months. Urinary N^ε-HEL levels were also reduced at 3 and 6 months, and urinary 8-OHdG levels were reduced at 6 months. Serum total and urinary total pentosidine levels in RA patients correlated with the number of swelling joints and tender joints, and urinary total pentosidine levels correlated with the Disease Activity Score using 28 joints (DAS28). This study demonstrated that etanercept acts as a regulator against pentosidine formation, oxidative DNA damage, and lipid peroxidation in RA patients.