Serum and colon mucosa micronutrient antioxidants: differences between adenomatous polyp patients and controls.

OBJECTIVES: Micronutrient antioxidants, by virtue of their free radical scavenging properties, are potential chemopreventive agents against colon cancer. Yet, little is known about the actual concentration of these antioxidants in colonic mucosa. It is also not known whether a relationship exists between serum and mucosal tissue antioxidant levels. Previous studies evaluating the occurrence of polyps after supplementation with vitamin E and beta-carotene have yielded mixed results. The aim of this study was to determine the concentrations of seven micronutrient antioxidants (alpha- and gamma-tocopherol, lutein, beta-cryptoxanthin, lycopene, and alpha- and beta-carotene) in colonic mucosa and to determine whether serum levels of each antioxidant could predict levels of that antioxidant in the right and left colon of patients with normal mucosa or in those with adenomatous polyps.
METHODS: Mucosal tissue concentrations and serum levels of antioxidants were determined in 10 patients with adenomatous polyps and 15 control subjects (GI patients with normal colonic mucosa). Mucosal tissue samples were obtained from both the right and left colon in all patients.
RESULTS: Patients with polyps similar serum antioxidant status similar to that of control. However, polyp patients had significantly lower concentrations of all seven antioxidants in both the right (p < 0.0070) and left colon (p < 0.0026) than did controls. Finally, serum antioxidant levels predict right and left colon antioxidant levels in controls but not in patients with polyps.
CONCLUSIONS: Patients with adenomatous polyps have low levels of micronutrient antioxidants in their colon mucosa. Because the serum levels of these antioxidants were similar in controls and polyp patients, our findings suggest an increased level of free radical activity in patients with polyps compared to normal subjects.