Abstracts
2000 Digestive Disease Week

# 2249 The Immunohistochemical Similarity of Cardiac Mucosa, Intestinal Metaplasia of the Cardia, and Barrett’s Esophagus.
Steve R. Demeester, Kumari S. Wickramasinghe, Reginald L. Lord, Adam Friedman, Los Angeles, CA

Introduction: Cardiac mucosa is a distinct type of simple columnar epithelium characterized histologically by the presence of mucous cells and the absence of parietal or chief cells. Within cardiac mucosa goblet cells, indicative of intestinal metaplasia (IM), may develop. Controversy surrounds the nature of cardiac mucosa, the etiology of IM limited to the gastroesophageal junction (CIM), and the relationship of CIM to Barrett’s esophagus. The aim of this study was to further characterize cardiac mucosa and IM on the basis of immunoreactivity to specific antibodies. Methods: Endoscopic and histologic findings were used to select Paraffinembedded, formalin fixed biopsy specimens from 30 patients who had undergone upper endoscopy for reflux symptoms. Ten patients had only cardiac mucosa, 10 had CIM, and 10 patients had Barrett’s esophagus. New slides from the original tissue blocks were cut and stained for cytokeratins (CK) 7 and 20, ornithine decarboxylase (ODC), and DAS-1 antibody. Each slide was examined in a blinded fashion by two investigators. Sections from a known colon cancer and breast cancer were used for positive controls. Results: The columnar epithelium of cardiac mucosa, CIM, and Barrett’s had an identical CK 7/20 staining profile, and differed markedly from both gastric and squamous mucosa. Heavy CK 7 staining of the surface mucous cells with lighter patchy staining of the deeper columnar cells was seen in all cases. In patients with IM the columnar cells demonstrated immunoreactivity, but goblet cells did not. Staining with CK 20 was similar to CK 7 but less intense in all groups. Immunoreactivity with ODC was none or trace in the cardiac mucosa and CIM sections. In the Barrett’s sections it was also minimal unless dysplasia was present, in which case moderate ODC staining was noted. Goblet cells from all patients with IM demonstrated heavy staining with DAS-1 antibody. Cardiac mucosa without IM and the columnar cells surrounding goblet cells in sections with IM did not demonstrate immunoreactivity with DAS-1 antibody. Conclusions: Without goblet cells the histology of CIM and Barrett’s esophagus would be identical to cardiac mucosa. The shared CK 7/20 profile of these tissues suggests a shared etiology and perhaps common origin. Likewise, the identical staining of CIM and Barrett’s with DAS-1 antibody, an antibody specific for Barrett’s, is further evidence that these two entities are closely linked and may represent two ends of a spectrum.