Serum nitric oxide and peroxynitrite levels in adult sero-positive rheumatoid arthritis treated with disease modifying antirheumatic drugs: a preliminary report

The contribution of inducible nitric oxide synthase (iNOS) to oxidative/nitrative stress is well documented in inflamed joints. Nitric oxide stimulates the synthesis of proinflammatory mediators and cytotoxic molecules with a pivotal role in apoptosis at the joint of rheumatoid arthritis. This study aimed to assess the serum levels of nitric oxide and peroxynitrite in sero positive rheumatoid patients treated with disease modifying antirheumatic drugs. Materials and methods: Sixteen known patients with sero-positive rheumatoid arthritis fulfilling the criteria of the American College of Rheumatology and on disease modifying antirheumatic drugs were allocated from the consultant clinic of rheumatology at Al-Yarmouk Teaching hospital in Baghdad, Iraq, from October 2004 to May 2005. The serum levels of nitric oxide and peroxynitrite were determined for patients as well as for another 16 healthy individuals serving as controls. Results: The mean serum levels of nitric oxide (116.9 mmol) and peroxynitrite (7.3 mmol) were significantly higher than the controls' levels of 46 mmol and 2.5 mmol, respectively. Females had non-significantly lower serum nitric oxide and higher serum peroxynitrite than corresponding males. Patients older than 50 years had non-significantly higher serum nitric oxide and lower serum peroxynitrite levels than those younger than 50 years old. There was a non-significant correlation between the serum levels of each of nitrogen species and the duration of disease or erythrocyte sedimentation rate as a marker of disease activity. Conclusion: Sero-positive rheumatoid patients treated with disease modifying antirheumatic drugs have significantly high serum nitric oxide and peroxynitrite levels that are not related to the duration or disease activity.