TY - JOUR T1 - Nitric oxide-derived species in synovial fluid from patients with juvenile idiopathic arthritis. JF - The Journal of Rheumatology JO - J Rheumatol SP - 992 LP - 997 VL - 31 IS - 5 AU - Ana Paola N Lotito AU - Marcelo N MuscarĂ¡ AU - Maria Helena B Kiss AU - Simone A Teixeira AU - Gilberto S Novaes AU - Ieda Maria M Laurindo AU - Clovis A Silva AU - Suzana Beatriz V Mello Y1 - 2004/05/01 UR - http://www.jrheum.org/content/31/5/992.abstract N2 - OBJECTIVE: To evaluate superoxide anion (O2-), nitrite/nitrate (NO2-/NO3-), and nitrotyrosine (NT) production and the contribution of myeloperoxidase (MPO) to the production of NT-containing proteins in the synovial fluid (SF) of patients with juvenile idiopathic arthritis (JIA). The affected tissues in inflammatory arthritis produce large amounts of nitric oxide (NO) or peroxynitrite (ONOO-) but there are no reports of NO or ONOO- participation in JIA. We also attempted to correlate our findings with variables of disease activity and articular damage. METHODS: We analyzed 40 patients with JIA, mean age 12.7 years, mean disease duration 7.8 years. O2- production was measured by cytochrome C reduction after incubation of 106 synovial fluid (SF) cells with or without phorbol myristate acetate (PMA), formyl-methionyl-leucyl-phenylalanine (FMLP) or opsonized zymosan. SF and serum NO2-/NO3- levels were measured by Griess reaction; NT was detected by Western blot. Myeloperoxidase (MPO) activity was estimated spectrophotometrically. Clinical and laboratory variables [erythrocyte sedimentation rate, C reactive protein (CRP), and radiological score] and interleukin 6 (IL-6) levels were evaluated. RESULTS: NO2-/NO3- production was greatly enhanced in the joints of JIA patients (54.6 +/- 3.2 micro M) when compared with serum (13.9 +/- 0.6 micro M; p < 0.001). NO2-/NO3- levels in SF were positively correlated with the number of infiltrating lymphomononuclear cells. NT-modified proteins detected in the SF showed a high correlation with radiological score, disease duration, CRP, and IL-6. CONCLUSION: Our results confirm the increased oxidative stress in children with JIA, suggesting a high in situ production of NO. The positive correlation between the expression of NT-modified proteins and variables of disease activity and damage is additional evidence that nitrogen and oxygen species may be involved in the joint destruction seen in patients with JIA. ER -