Lipid peroxidation markers in Crohn's disease: the associations and diagnostic value

Background: Crohn's disease (CD) is an incurable and difficult to diagnose condition. While high sensitive C-reactive protein (CRP) remains the best biochemical marker, we evaluated the diagnostic usefulness of lipid peroxidation indices. Methods: Malondialdehyde/thiobarbituric acid-reactive substances (MDA/TBARS), peroxidation potential (PP), lipid hydroperoxides (ROOH), oxidized-low density lipoprotein (oxLDL), and oxLDL antibodies (OLAB) were assessed in 52 CD patients and 99 volunteers and referred to clinical activity, inflammation, nutritional and antioxidant status. Results: MDA/TBARS were higher in CD while oxLDL and PP decreased in active disease and ROOH and OLAB did not differ. oxLDL and PP negatively and OLAB positively correlated with CD activity. MDA/TBARS positively correlated with IL-6 and SOD-1 and negatively with catalasc. IL-6 and SOD-1 explained 24% in MDA/TBARS variability. PP negatively correlated with CRP, platelets, and IL-6 and positively with glutathione peroxidase-1, paraoxonase-1, cholesterol, triglycerides, and albumins. Cholesterol and CRP explained 57% in PP variability. oxLDL negatively correlated with IL-1 and IL-6 and positively with glutathione peroxidase-1, paraoxonase-1, cholesterol, and albumins. Paraoxonase-1 explained 17% of oxLDL variability. OLAB positively correlated with IL-1 explaining 10% in its variability and negatively with cholesterol. MDA/TBARS were the best predictor of CD, comparable to CRP, with high specificity (MDA/TBARS sensitivity and specificity: 75% and 90%; CRP: 76% and 93%). Combined assessment of MDA/TBARS and CRP improved sensitivity (94%) corresponding with acceptable specificity (81%). Conclusions: MDA/TBARS are elevated in CD and may help to rule the disease out, while the combined evaluation with CRP may serve for CD confirmation. oxLDL and PP depended on substrate availability, decreased in CD.