Further studies on Barretts mucosa in baboons: metaplastic glandular cells produce sialomucin.

backgroundIn humans and in baboons, protracted gastro-esophageal reflux (GER) transforms the squamous-lined esophagus into columnar-lined (that is Barrett's mucosa, BM). Alcian blue stain (AB) is used to evidence sialomucin-producing goblet cells in human BM.

aimTo assess the frequency and distribution of sialomucin-producing cells in BM in baboons. MATERIALS AND

methodsSections from 137 consecutive baboon esophagi were alternatively stained with hematoxylin-eosin (H&E) and with AB (pH 2.5), without counterstain.

resultsOut of 137 baboons, 131 (95.6%) had BM. Columnar and intramucosal glandular cells produced sialomucin in all 131 of these animals. Many BM cells were ballooned and filled with sialomucins, despite goblet cells not being found in H&E sections.

conclusionIn humans, protracted GER is a disease requiring medication that may lead to BM; AB stains mainly goblet cells and occasional columnar cells in BM. In baboons, in contrast, BM is a natural postnatal process of adaptation to GER, triggered by regurgitation and rumination. AB stains all columnar and intra-mucosal glandular cells. Sialomucin-overstuffed cells were more frequent and larger in baboons than in humans. The extra load of sialomucin in BM might be an integrated part of the postnatal life-long process of adaptation to regurgitation and rumination in baboons.