Expression of Sonic hedgehog (SHH) and CDX2 in the columnar epithelium of the lower oesophagus.

Background: Decreases in Sonic hedgehog (SHH) and CDX2 expression are associated with atrophy and intestinal metaplasia in the gastric mucosa. The pathogenesis of development of Barrett's oesophagus is still unclear.
Objective: To examine the gene expression of CDX2 and SHH and their signalling pathways in the columnar epithelium and the association with endoscopic appearance, gastric pH or bile acids.
Subjects/methods: Sixty-three patients with metaplastic columnar epithelium of the lower oesophagus were studied. Whole biopsy specimens and microdissected tissues were examined for messenger RNA.
Results: BMP4 expression was significantly higher in patients with tubular mucosal patterns of columnar epithelium visualised by Narrow Band Imaging with magnification. The expression of SHH was significantly lower and that of CDX2 was higher in the goblet columnar epithelium than in non-goblet columnar epithelium. CDX2 expression was significantly higher in the patients with hypoacidity than in the others. BMP4 and PTCH1 expression was significantly higher in the group with higher concentrations of deoxycholic acid than in the group with lower concentrations.
Conclusions: SHH might be the initial factor inducing columnar metaplasia, and subsequent or simultaneous BMP4 stimuli might induce the CDX2 expression that causes goblet-cell metaplasia.
(Copyright © 2010 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.)