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

Background : TFF3 peptide is secreted by salivary glands and is expre ssed 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 , corpu s and cardia .Additional biopsies from the antrum and corpu s served to determin e H. pylori status by rapid urease test, culture and histology.The gastritis parameters were graded according to the updated Sydne y system.Biopsies were tested for TFF 3 by Western-Blot (WB) using a rabbit IgG antibody against a synthetic peptide compo sed of 1I amino acids of the C terminal end of TFF 3. TFF3 mRNA expre ssion 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 addition al 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 esophag eal 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 actuall y expressed locally in the stomach.The failure to detect TFF3 in the esophagus contradicts a major contamination by saliva .A possible contamination by duodenal-gastric reflux should also be excluded in future studies.The correlation of TFF3 to intestinal metaplasia of the stomach warrant s further investigation.