Peripheral lymphocyte DNA damage and oxidative stress in patients with ulcerative colitis.

INTRODUCTION Ulcerative colitis (UC) is a fairly common chronic inflammatory disorder. Chronic inflammation may contribute to the risk of colorectal cancer through the accumulation of specific products resulting from DNA damage. Previous studies reported that DNA damage and oxidative stress play a significant role in the pathophysiology of UC, but the results are inconsistent. OBJECTIVES In the present study, we investigated peripheral DNA damage and oxidative stress in patients with UC. PATIENTS AND METHODS The study included 20 patients with UC and 20 controls. Peripheral lymphocyte DNA damage was measured using the alkaline comet assay. Plasma total antioxidant capacity (TAC), total oxidant status (TOS), and oxidative stress index (OSI) were determined. RESULTS DNA damage levels, TOS, and OSI were significantly higher in patients with UC than in controls (P <0.001 for all parameters), while TAC was significantly lower (P <0.001). DNA damage was significantly correlated with TOS, TAC, and OSI (r = 0.604, P <0.001; r = -0.593, P <0.001; and r = 0.716, P <0.001, respectively). Moreover, TAC levels were significantly correlated with TOS and OSI (r = 0.604, P <0.001; r = -0.399, P <0.05; and r = -0.513, P <0.05, respectively). CONCLUSIONS Our results show that increased peripheral DNA damage and oxidative stress seem to be associated with decreased antioxidant levels and thus may in part contribute to the development of colorectal cancer associated with UC.