Oxidation of Uric Acid in Rheumatoid Arthritis: Is Allantoin a Marker of Oxidative Stress?

• Published in: Free radical research Vol. 38; no. 6; pp. 623 - 628
• Main Authors: Yardim-Akaydin, Sevgi, Sepici, Aylin, Özkan, Ye im, Torun, Meral, im ek, Bolkan, Sepici, Vesile
• Format: Journal Article
• Language: English
• Published: England Informa UK Ltd 01.06.2004; Taylor & Francis
• Subjects: Age Factors; Allantoin; Allantoin - blood; Arthritis, Rheumatoid - blood; Biomarkers - blood; Female; Humans; Hypochlorous acid; Male; Middle Aged; Oxidation-Reduction; Oxidative Stress - physiology; Postmenopause - blood; Premenopause - blood; Rheumatoid arthritis; Sex Factors; Uric acid; Uric Acid - blood; Uric Acid - metabolism
• ISSN: 1071-5762; 1029-2470
• DOI: 10.1080/10715760410001694044

Free radicals are implicated in many diseases including atherosclerosis, cancer and also in rheumatoid arthritis. Reaction of uric acid with free radicals, such as hydroxyl radical and hypochlorous acid (HOCl) results in allantoin production. In this study, we measured the serum allantoin levels, oxidation products of uric acid, as a marker of free radical generation in rheumatoid arthritis. Fasting blood samples were obtained from 21 rheumatoid patients and 15 healthy controls. In this study, the serum allantoin and uric acid levels were measured by a gas chromatography-mass spectrometry method and the ratios were calculated. The mean allantoin and uric acid levels and ratios in the patient group were 22.1±11.3, 280.5±65.0 and 8.0±3.7  M, while in the control group they were 13.6±6.3, 278.3±53.6 and 4.9±2.1  M, respectively. The effects of gender, age, menopausal status, duration of disease and medications on serum allantoin and uric acid levels of the patient and control groups were studied. Our results suggest that uric acid acts as a free radical scavenger and thus is converted to allantoin. Increased allantoin levels suggest the possible involvement of free radicals in rheumatoid arthritis.