Pathophysiological investigation of the gastric surface mucous gel layer of patients with Helicobacter pylori infection by using immunoassays for trefoil factor family 2 and gastric gland mucous cell-type mucin in gastric juice.

ABSTRACT

BACKGROUND: The trefoil factor family (TFF) 2 protein is produced by gastric gland mucous cells (GMCs), and the secreted TFF2 shares a mucosal barrier function with GMC-type mucin. Recently, we presented an enzyme-linked immunosorbent assay (ELISA) method for measurement of GMC-type mucin in the gastric juice. AIMS: We aimed to develop an ELISA for TFF2 and to assess pathophysiological changes in the gastric surface mucous gel layer (SMGL) of patients with Helicobacter pylori infection. METHODS: The distribution of TFF2 and GMC-type mucin in the SMGL was immunohistochemically determined. The ELISA for TFF2 was based on a polyclonal goat antibody. Recombinant TFF2 was employed to prepare the calibrators. TFF2 and GMC-type mucin in the gastric juice in healthy individuals (n = 33) and patients with gastritis (n = 37), gastric ulcer (n = 16), and duodenal ulcer (n = 10) were assayed using ELISA. RESULTS: TFF2 and GMC-type mucin were immunohistochemically co-localized in the gastric SMGL and GMCs. The TFF2 levels in the patients were significantly higher than those in the healthy individuals. Further, the TFF2 levels in the H. pylori-positive patients were significantly higher than those in the H. pylori-negative patients, and decreased after the eradication of the infection. GMC-type mucin levels showed a tendency similar to that of TFF2 levels. CONCLUSIONS: The upregulation of TFF2 and GMC-type mucin secretion may reflect the response of the gastric mucosa to H. pylori-induced injuries. TFF2 and GMC-type mucin secreted into the SMGL may protect the gastric mucosa against H. pylori.