The relationships between plasma and erythrocyte antioxidant enzymes and lipid peroxidation in patients with rheumatoid arthritis

Objective. The present study was undertaken to evaluate the activities of s ome key erythrocyte and plasma enzymes participating in free radical metabo lism and the end product of lipid peroxidation in rheumatoid arthritis, and whether there are any differences for these parameters between newly diagn osed untreated patients and rheumatoid arthritis patients on drug therapy. Patients and methods. Superoxide dismutase and catalase activities, and mal ondialdehyde levels were determined in erythrocytes and plasma samples from 54 patients with rheumatoid arthritis (21 of whom without any treatment an d 33 on classical therapy regimens) and from 33 healthy controls. Results. There were no statistically significant differences in mean values of activ ities of the erythrocyte enzymes between the patients and controls. Malondi aldehyde levels were significantly increased in both newly diagnosed untrea ted patients and patients on drug therapy compared to control subjects. Mal ondialdehyde levels were lower in the treated group than the newly diagnose d untreated group (0.214 +/- 0.111 mu mol/L and 0.388 +/- 0.075 mu mol/L, r espectively) (P < 0.0001). Mean plasma superoxide dismutase activity was lo wer in the group of newly diagnosed untreated patients compared to those of the treated and control groups (1.31 +/- 0.69 U/mL, 1.79 +/- 0.94 U/mL and 2.48 +/- 0.95 U/mL, respectively) (P < 0.0001, untreated vs control groups ). Conclusions. These results suggest sufficient antioxidant enzyme activit ies in erythrocytes in patients with rheumatoid arthritis and also increase d lipid peroxidation end products in newly diagnosed untreated patients com pared to control group and patients on drug therapy. (C) 2001 Editions scie ntifiques et medicales Elsevier SAS.