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

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. 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. 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. 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. 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.