RESUMEN
BACKGROUND & AIMS: Preclinical studies in animal models, human epidemiological data, and clinical trials in patients with adenomatous polyposis have consistently indicated that sulindac and other nonsteroidal antiinflammatory drugs or cyclooxygenase inhibitors have the greatest potential efficacy among current candidates for colon tumor chemopreventive agents. However, at highly effective doses they all have some risk of toxicity, and their therapeutic profile might be improved by use at lower, more tolerable doses, in combination with a second agent acting via other mechanisms. METHODS: Sulindac was tested in combination with ursodeoxycholic acid (ursodiol), a naturally occurring 7-B-epimer of the bile component chenodeoxycholic acid, for prevention of adenomas in the Min mouse model of adenomatous polyposis. RESULTS: Ursodeoxycholic acid caused a dose-dependent decrease in the number of intestinal tumors. Unlike sulindac and other nonsteroidal anti-inflammatory drugs, which are quite beneficial in the distal intestine but are somewhat less effective in the proximal small intestine (especially the clinically important periampullary duodenum), ursodeoxycholate had equal efficacy throughout the entire intestine, both proximal and distal. Combined treatment with low-dose sulindac was less toxic, with normal weight gain and fewer gastrointestinal ulcerations than high-dose sulindac. Combined treatment with sulindac and ursodeoxycholate was more effective than either agent alone for the prevention of tumors throughout the entire intestine. CONCLUSIONS: These experiments provide the first evidence that ursodeoxycholic acid is effective for preventing adenomas in an animal model. Cyclooxygenase inhibition, when combined with this naturally occurring bile component, may become a promising approach for colon cancer prevention.