Serum paraoxonase 1 activity and malondialdehyde levels in patients with ulcerative colitis

Abstract

This study was designed to evaluate the oxidative and antioxidative status in patients with ulcerative colitis by detecting antioxidant enzyme paraoxonase I activity together with the level of a well-known marker of oxidative stress, malondialdehvde. Serum paraoxonase 1 activity and malondialdehyde levels were analysed in 30 patients with ulcerative colitis and 30 controls using a spectrophotometric method; correlation analysis was made between these variables. Serum malondialdehyde levels were higher in the ulcerative colitis group (median: 2.5, range: 0.5-9.4 nmol ml(-1)) than among the controls (median:1.1. range: 0.5-2.3 nmol/ml(-1); p < 0.001) whereas paraoxonase I activities were lower in the ulcerative colitis group (median: 158.4, range: 61.6 -264.1Ul(-1)) than in the control group (median: 233.3, range: 114.4-431.0 Ul(-1); p < 0.001). There was no correlation between serum malondialdehyde level, paraoxonase 1 activity and disease activity. (1) Increased reactive oxygen metabolites levels in ulcerative colitis may result in a pro-oxidation environment, which in turn could result in decreased antioxidant paraoxonase 1 activity and increased malondialdehyde levels, (2) increased cytokines may be a possible cause of decreased paraoxonase 1 activity and (3) decreased serum paraoxonase 1 activity may be a part of an inflammatory response. Copyright (c) 2005 John Wiley & Sons, Ltd