Antioxidant defense capacity in scieroderma patients

Background: Oxidative stress is associated with scleroderma (systemic sclerosis) and is supposed to favor disease progression by complex effects on the vascular endothelium and on fibroblasts. Methods: Plasma oxidative process marker, thiobarbituric acid-reactive substances, and several markers of antioxidant defense capacity (plasma total antioxidant activity, serum albumin, uric acid and glutathione, superoxide dismutase and catalase) were evaluated by spectrophotometric methods using blood samples collected from 23 scleroderma patients and 21 healthy controls. Results: In scleroderma patients, thiobarbituric acid-reactive substances levels (mmol/L plasma) were significantly elevated (29.3 +/- 5.8) compared with healthy controls (16.6 +/- 3. 1, p < 0.001). Total antioxidant activity (mmol Trolox/L) was significantly lower in scleroderma patients than in controls (1.29 +/- 0.13 vs. 1.55 +/- 0.23, p < 0.001), as well as the antioxidant gap (mmol Trolox/L) (0.57 +/- 0.18 vs. 0.92 +/- 0.22, p < 0.001). Superoxide dismutase activity (IU/g hemoglobin) was markedly decreased in patients as compared with controls (395 184 vs. 659 211, p < 0.001). Conclusions: Lower plasma total antioxidant activity and plasma antioxidant gap in scleroderma patients show that plasma antioxidant defense is deficient in scleroderma patients. As previous studies on this issue are controversial, the decreased erythrocyte superoxide dismutase activity found in the patients in this study needs further investigation.