Antioxidant enzymes, glutathione and lipid peroxidation in peripheral blood of children affected by coeliac disease.

Background: Oxidative stress has been implicated in the pathogenesis of coeliac disease. The aim of this study was to examine the modulation of the biochemical response to oxidative stress in untreated and treated coeliac disease.
Methods: The study involved peripheral blood samples from 39 paediatric patients (18 with active, 11 with silent form of the disease, 10 on gluten-free diet [GFD]) and 30 control subjects. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR), as well as the concentrations of total glutathione (GSH) and lipid hydroperoxides (LOOH) were determined in patients and controls.
Results: In comparison to the controls, a significant increase in SOD activity was found in the active group (P<0.05), while CAT activity was elevated in GFD group (P<0.05). GPx activity was lower in patients than in controls (active and silent, P<0.001; GFD, P<0.01). GSH contents were significantly reduced in all patient groups (P<0.001) as well, while the concentration of LOOH was elevated in active and silent group (P<0.001). The concentration of LOOH correlated negatively with the activity of GPx (r = -0.32, P<0.01) and the concentration of GSH (r = -0.70, P<0.001). A significant positive correlation was found between the concentration of GSH and the activity of GPx (r = 0.57, P<0.001).
Conclusions: The results show evidence of increased oxidative stress in untreated coeliac disease. Although LOOH were not significantly elevated in the GFD group, changes in antioxidant enzyme activities and GSH content demonstrate that oxidative stress persists even in treated patients.