The Mutagenic Potential of Duodenoesophageal Reflux

In Brief Summary Background Data: Duodenogastric–esophageal reflux disease is directly linked to Barrett's esophagus and to the development of esophageal adenocarcinoma. Despite this link, little is known about the mutagenic potential of refluxed material on the esophageal mucosa. We hypothesize that the reflux of gastric and duodenal content causes mutations in esophageal mucosa in vivo. Methods: Seven Sprague Dawley/Big Blue F1 lacI transgenic rats underwent esophagoduodenostomy (ED) to surgically create duodeno–gastric–esophageal reflux. Fourteen nonoperated rats served as negative (n = 7) and as positive (n = 7/methyl-N-amyl-nitrosamine [MNAN] intraperitoneally) controls. The animals were killed 16 weeks after operation or injection, the entire esophageal mucosa was harvested, and mutation frequency was determined through standard Big Blue Mutagenesis Assay. Results: Gross esophagitis was evident in all operated animals. The frequency of lacI mutations in esophageal mucosal cells of animals with ED was significantly higher, nearly 1.5-fold, than that of nonoperated animals. Nitrosamine administration resulted in a nearly 20-fold increase of lacI mutation frequency. Thirteen mutations were successfully sequenced, 46% occurred at CpG dinucleotide sites and 61% were either C to T or G to A transitions. Conclusions: The data provide preliminary evidence of the mutagenic potential of bile reflux on esophageal epithelium. The specific mutations are markedly higher than would be expected by chance and are similar to that found in p53 mutations of human esophageal adenocarcinoma, providing a link to human esophageal cancer. The frequency and spectrum of mutations of the lac-I gene were investigated in a well-described rat model of esophageal carcinoma. Surgical creation of duodenoesophageal reflux resulted in a significant increase in lac-I mutation frequency, which, on analysis, had a spectrum of mutations remarkably similar to those seen in human esophageal adenocarcinoma.