The combined presence of H pylori infection and gastro-oesophageal reflux disease leads to an up-regulation of CDX2 gene expression in antrum and cardia.

BACKGROUND

CDX2 is an epithelial transcription factor that regulates intestinal differentiation and is involved in the development of intestinal metaplasia (IM).

AIM

To analyse the expression of CDX2 in the gastric mucosa in various locations and its relationship to Helicobacter pylori infection and gastro-oesophageal reflux disease (GORD).

METHODS

69 patients with upper gastrointestinal symptoms were stratified into four groups according to their H pylori and GORD status. Patients without infection and without GORD were the reference group (H pylori(-)/GORD(-)). Biopsies from the antrum, corpus and cardia were assessed by histopathology according to the updated Sydney System. CDX2 transcription levels were determined by quantitative RT-PCR and immunohistochemistry.

RESULTS

CDX2 gene expression was significantly up-regulated in antral and cardia mucosa of patients with both H pylori infection and GORD (26- and 100-fold, respectively; p<0.05), but remained unchanged in corpus mucosa. If only H pylori infection or GORD was present, CDX2 expression levels were 6- to 11-fold increased in the antrum, but without reaching statistical significance. CDX2 expression correlated positively with the degree of IM (p<0.01) and the degree of H pylori induced inflammation (p<0.05). Gene expression data were confirmed immunohistochemically by the detection of CDX2 in areas of IM and in focally distributed CDX2-expressing cells in non-metaplastic gastric mucosa.

CONCLUSIONS

The combined presence of H pylori infection and GORD leads to an up-regulation of CDX2 gene expression in cardia and antral mucosa, but not in the corpus.