Background: To understand the pathophysiology of duodenal ulcer disease, it is important to identify and quantitate gastric metaplasia of the duodenum. Methylene blue dye is absorbed well by intestinal mucosa, but not by gastric mucosa. Our aim was to validate a methylene blue staining technique for measurement of gastric metaplasia in the duodenum.
Methods: Eight subjects with chronic duodenal ulcer disease and seven subjects with other upper intestinal disorders underwent duodenal methylene blue staining after application of a mucolytic agent. Biopsy specimens were obtained from blue-stained and pale unstained areas and assessed for gastric metaplasia histologically.
Results: Pink or pale unstained duodenal areas had more gastric surface cell metaplasia than blue-stained areas. Unstained duodenum was also more likely to have extensive (more than 25% of the biopsy specimens) gastric metaplasia (60%) than blue-stained areas (9%). Subjects with duodenal ulcer disease had more unstained mucosa than controls.
Conclusion: Methylene blue staining of the duodenum is useful to identify and quantitate gastric metaplasia.