INF-β1b therapy modulates L-arginine and nitric oxide metabolism in patients with relapse remittent multiple sclerosis.

The scope of this study is the examination of NO(2)+NO(3), 3-nitrotyrosine (3-NT), S-nitrosothiols (RSNO), arginase activity and asymmetric (ADMA) and symmetric (SDMA) dimethyl-L-arginine concentrations in plasma of MS patients during interferon-β1b therapy. The study population included 15 (12 women, 3 men) untreated MS patients and 12 (10 women, 2 men) interferon-β1b treated MS patients with clinically definite relapsing MS (McDonalds criteria) for at least 1 year and a baseline EDSS score of 1.0 to 3.5 inclusive. Patients were treated with 250 μg IU interferon-β1b s.c. every second day during 30 months. The disease course was evaluated using correlations between baseline EDSS score and relapse rates in both groups. During interferon-β1b treatment, EDSS scores in treated patients were decreased compared to untreated ones - after 18 and 30 months (p<0.05). In interferon-β1b treated MS patients, NO(2)+NO(3), 3-NT and RSNO plasma concentrations were significantly lower (p<0.05), while arginase activity, ADMA and SDMA levels were significantly increased (p<0.05) during the therapy, compared to the baseline levels in treated patients. The investigated parameters may be the new biomarkers, providing information for the therapeutic approach and valuable in clinical monitoring.