Evaluation of oxidant and antioxidant status and relation with prolidase in systemic sclerosis

Systemic sclerosis (SSc) is a disease characterized by fibrosis of the skin and organs; it is associated with diffuse fibroproliferative microangiopathy and autoimmune background. The studies have shown that the production of excessive free radicals and increased collagen synthesis by the fibroblasts play an important role in the pathophysiology of SSc. Prolidase is an important marker in collagen turnover. We aimed to compare total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), and prolidase levels of SSc patients and healthy controls. We also investigated the relationship between prolidase and oxidative stress. A total of 38 SSc patients and 33 healthy volunteers were included in the study. Serum TAS, TOS, and prolidase activity were evaluated in the groups. It was found that the TOS and OSI levels of patients were higher than those in the control group (P = 0.012 and 0.015, respectively), whereas TAS was not significantly different between groups (P = 0.451). Prolidase activity was lower in patients than in controls (P = 0.008). There was a weak correlation between prolidase and OSI in patients. It was found that TAS was lower by marginal significance in the patients with lung and gastrointestinal tract (GT) involvement than the patients without those (P = 0.067 and 0.059, respectively). Our data suggest that oxidative stress is increased in SSc. TAS is decreased in patients with lung and GT involvement. These results support that antioxidant treatment may be useful in SSc, especially in patients with lung and GT involvement. Antioxidant treatment may prevent organ involvement in SSc. TAS may be a marker that predicts the risk of involvement of a specific organ. In addition, prolidase may be a marker of SSc.