Plasma S-nitrosothiols in systemic sclerosis and Raynaud’s phenomenon

Abstract

Systemic sclerosis (SSc) is a skin disease marked by overproduction of collagen, vascular dysfunction and dysregulation of NO biosynthesis. All patients exhibit Raynaud’s phenomenon. In some cases internal organs are involved (dSSc). In limited SSc (lSSc), lesions are largely confined to skin. NO and S-nitrosothiols (RSNO) inhibit collagen biosynthesis in vitro. The study investigates levels of RSNO in patients with SSc and primary Raynauds’ phenomenon (RP). RSNO and NO 2 - were measured by chemiluminescence (NO and ozone) in plasma of patients (78% female) and controls. Skin scores show the level of disease. Statistical analyses were performed by one way ANOVA and Newman–Keuls tests. A striking reduction in the level of detectable RSNO was observed in most patients compared to controls. In healthy controls, RSNO decreased with age (above 40 years). The following levels were found in controls (6 ± 0.8 SEM, n = 26), patients with lSSc (1.31 ± 0.37, n = 34, P = 1.06E−06), dSSc (0.73 ± 0.41, n = 11, P = 00025) and RP (2.12 ± 0.57, n = 16, P = 0.002). In SSc patients, high skin scores correlated with low RSNO levels (dSSc). There were no differences in nitrite levels between groups. The results suggest a link between the availability of NO as S-nitrosothiols and the severity of SSc.