Markers of lipid peroxidation and antioxidant status in the serum and saliva of patients with active Crohn disease

Introduction Increased oxidative stress has been implicated in the pathogenesis of Crohn disease (CD). Except for C‑reactive protein (CRP), good biological markers of CD activity are lacking.
Objectives We aimed to investigate the diagnostic usefulness of selected markers of oxidative stress in the serum and saliva of patients with active and inactive CD.
Patients and methods A total of 58 patients with confirmed CD (32 with active CD, 26 with inactive CD, and 26 healthy controls) were prospectively enrolled to the study. The markers examined were malondialdehyde (MDA), ferric reducing ability of plasma (FRAP), reduced glutathione (GSH), and catalase (CAT).
Results MDA levels were higher in the serum and saliva of patients with active CD than in those with inactive CD and controls and were positively correlated with the Crohn’s Disease Activity Index (r = 0.8, P <0.001) and CRP (P <0.001). Serum and saliva antioxidant indicators (FRAP and GSH) were decreased in both CD groups compared with controls and were negatively correlated with clinical activity and inflammation (FRAP, r = –0.5, P <0.001; GSH, r = –0.5, P <0.001; and CAT, r = –0.5, P <0.001).
Conclusions The increased lipid peroxidation and decreased antioxidant activity in serum and saliva confirm that CD patients are under oxidative stress. The positive correlations of MDA with the clinical activity and inflammation, as well as the comparison of the receiver operating characteristic curves for MDA and CRP, suggest that MDA could be a good diagnostic marker of CD.