TFF3 in esophageal, gastric mucosa as well as in gastric juice

Abstract

Background : TFF3 peptide is secreted by salivary glands and is expressed throughout the intestine but is reported to be absent from gastric tissue. TFF3 is co-secreted with mucins and is assumed to be involved in epithelial protection and repai r. Aim: To find TFF3 in gastric tissue and juice, and find out whether TFF3 is expressed in gastric tissues. Patients and Methods: In n=9 consecutive patients undergoing upper gastrointestinal endoscopy, two gastric biopsies each were taken from the antrum, corpus and cardia . Additional biopsies from the antrum and corpus served to determine H. pylori status by rapid urease test, culture and histology. The gastritis parameters were graded according to the updated Sydney system. Biopsies were tested for TFF3 by Western-Blot (WB) using a rabbit IgG antibody against a synthetic peptide composed of 1I amino acids of the C terminal end of TFF3. TFF3 mRNA expression was determined by RT-PCR using a human specific primer pair. In a further two groups of patients, esophageal biopsies (n= 9) and gastric ju ice (n= 17) were tested for TFF3 by WB. Results: WB analysis of the gastric biopsies detected TFF3 in 4 of the 9 patients. RT-PCR detected mRNA in these and in an additional 3 patients (total 7 of 9). RT-PCR was more frequently positive in antral biopsies compared to corpus or cardia. TFF3 found by RT-PCR and by WB was inversely correlated with the H. pylori status. The strongest bands were found in two patients with gastric atrophy, intestinal metapl asia. and autoimmune gastritis. TFF 3 in gastric juice was detectable in 13 of 17 patients with no correlation to H. pylori infection or gastritis paramete rs. No TFF3 was found in esophageal biopsies . Conclusions: TFF3 was found in gastric mucosa and juic e with an interindivi dual variability yet to be explained and is in stark contrast to previous studies. Detection of mRNA in gastric biopsies suggests that TFF3 is actually expressed locally in the stomach. The failure to detect TFF3 in the esophagus contradicts a major contamination by saliva . A possible contamination by duodenalgastric reflux should also be excluded in future studies. The correlation of TFF3 to intestinal metaplasia of the stomach warrants further investigation. 5899