High expression of gastrin receptor protein in injured mucosa of Helicobacter pylori-positive gastritis.

BACKGROUND AND AIM: Gastrin is a growth factor for the gastric epithelial cells. However, it is unknown how gastric receptor (GR) expression is regulated in the gastric mucosa. We studied GR expression using a newly raised antibody and investigated the relationship between GR expression and gastritis. METHODS: Gastric receptor expression in 63 human gastric mucosa was studied. Helicobacter pylori infection and histological gastritis status were evaluated in gastric biopsy samples. In gastric ulcer cases, additional biopsy specimens were taken from injured mucosa. Fasting sera were collected and serum gastrin level evaluated. MKN-28 cells were cultured at various pH conditions, and the change in GR expression was determined. RESULTS: Gastric receptor expression was detected in the foveolar epithelium of the gastric mucosa, and its expression was stronger in patients infected with H. pylori. In particular, higher expression was detected in regenerating injured mucosa. There was no association between gastritis score/serum gastrin level and GR expression in H. pylori-positive cases. In MKN-28 cells, GR protein expression was lower in neutral conditions than in acidic or alkaline conditions. CONCLUSION: Gastric mucosal injury with H. pylori infection destroys the pH barrier on the foveolar epithelium and may induce GR expression through pH changes.

Helicobacter pylori cagA polymorphism and gastric inflammation: an international comparison between Japanese and Brazilian patients.

OBJECTIVE: Gastritis induced by Helicobacter pylori can cause the onset of gastric cancer, and H. pylori cytotoxin associated gene A (cagA) is considered to be an important factor for its development. We investigated the relationship between the grades of gastritis and cagA phenotype in Japanese and Brazilian patients. MATERIAL AND METHODS: We studied 47 Brazilian and 47 age-, gender-matched Japanese patients. Status of H. pylori infection, the degree of histologic gastritis, and the levels of serum pepsinogen levels were evaluated. DNA was extracted from paraffin-embedded sections and a portion of the cagA gene was amplified using the polymerase chain reaction, followed by direct sequencing of the fragment. We investigated the cagA subtype using a newly developed restriction fragment length polymorphism (RFLP) system. RESULTS: In H. pylori-positive patients, the grades of histological and serological gastritis were more prominent in the Japanese subjects than their Brazilian counterparts, although no difference was detected in the H. pylori-negative subjects. According to cagA phenotype analysis, our RFLP system was helpful for evaluating cagA phenotype, and we found that the prevalence of the East Asia subtype was significantly higher in the Japanese subjects than in the Brazilian. CONCLUSION: Infection with H. pylori possessing the East Asian cagA gene contributes to the progression of gastritis.

Plaunotol induces a comparative increase of acidic mucin fraction in gastric juice.

BACKGROUND/AIMS: Gastric mucus protects the gastric mucosa. Plaunotol, a gastroprotective agent, has been shown to increase mucus production in animal models. However, it is unclear whether plaunotol benefits human gastric mucus secretion. METHODOLOGY: Twenty-five patients with atrophic gastritis were studied. All patients underwent gastroendoscopy and gastric juice was collected before and after plaunotol treatment for 3 months. Gastric juice mucin was examined by gel filtration as well as anion-exchange chromatography. The identification of each fraction was examined by enzyme-linked immunosorbent assay (ELISA) with the use of HGM75 and HIK1083, antibodies against mucin from surface mucus cells and from gastric glandular mucus cells, respectively. RESULTS: Plaunotol significantly increased the total gastric juice volume (7.8mL before vs. 10.7mL, after administration; p=0.03). By anion exchange chromatography, we detected three mucin fractions (Fr I-III). Fr I strongly reacted with HGM75 but did not react with HIK1083. The other fractions (Fr II, III) reacted with HIK1083 but weakly reacted with HGM75. After administration of plaunotol, a significant increase in Fr III (acidic mucin) was observed (p=0.02). CONCLUSIONS: Long-term administration of plaunotol changes the composition of gastric juice mucin, including a significant increase in the proportion of acidic mucin fraction.

Little necessity of acid inhibition against proton pump inhibitor rebound effects and prior helicobacter pylori eradication therapy in gastric ulcer patients: a randomized prospective study.

BACKGROUND/AIMS: Helicobacter pylori (H. pylori) eradication therapy increases acid secretion and promotes the development of gastroesophageal reflux disease (GERD) and reflux esophagitis (RE). Rebound acid hypersecretion develops after the use of proton pump inhibitors (PPI). We examined the clinical necessity of acid inhibitors to prevent GERD or RE caused by PPI rebound phenomenon and prior H. pylori eradication therapy. METHODOLOGY: We enrolled 39 patients who underwent successful H. pylori eradication therapy prior to endoscopic mucosal resection of gastric cancer. After 8-week rabeprazole treatment for iatrogenic ulcer, they were randomly divided into two groups (who took nizatidine (group N) and sofalcone (group S)), and took each for 16 weeks, we compared RE/GERD symptoms with the baseline by endoscopy and QUEST score. RESULTS: All patients had corpus atrophy in which there was no difference between the two groups. Only 1 patient in group S (5.9%) developed symptomatic GERD, and 1 patient in group N (4.5%) developed RE. CONCLUSIONS: In severe atrophic gastritis patients, there is little clinical necessity of acid inhibitors to prevent GERD/RE caused by PPI rebound and prior H. pylori eradication therapy.

Clinical prevention of gastric cancer by Helicobacter pylori eradication therapy: a systematic review.

Helicobacter pylori (H. pylori) infection plays an important role in gastric carcinogenesis. We conducted a systematic review concerning gastric cancer development after H. pylori eradication therapy. In total 15 papers matched our criteria, the results were reviewed. The H. pylori eradication therapy statistically diminished the prevalence of clinical gastric cancer by approximately one-third. The studies from Japan supported this conclusion; however, studies from overseas reported conflicting results. The differences in these conclusions lie in the diagnostic ability of endoscopic examination, since the clinical stage was quite different between these studies. Gastric cancer that developed after eradication revealed a mainly intestinal type histology and depressed-type appearance. The following are possible reasons for reduced gastric cancer: (1) eradication therapy inhibits the new occurrence of gastric cancer, (2) eradication regresses or inhibits the growth of gastric cancer, and (3) eradication interferes with the discovery of gastric cancer. Considering the biological nature of cancer cell proliferation, a sufficiently long-term follow-up may clarify the effect of eradication therapy on inhibition of the development (not discovery) of gastric cancer and reduction of gastric cancer-related mortality.

Role of the gastrin-gastrin receptor system in the expansive growth of human gastric neoplasms.

BACKGROUND AND AIM: Gastrin is one of the most important gut hormones. However, the role of the gastrin-gastrin receptor (GR) system in the growth of gastric tumors is still unclear. METHODS: We examined serum gastrin levels in 957 patients with early gastric carcinoma. Next, we raised antibody against the GR and examined GR expression in 5 gastric carcinoma cell lines and 48 human gastric tumor tissues. In 28 cases, Helicobacter pylori eradication therapy was performed and morphological tumor changes were examined. RESULTS: Serum gastrin levels were significantly higher in patients with elevated tumors than in patients with depressed tumors (p = 0.02). All gastric carcinoma cell lines expressed GR. Thirty-one of 48 (65%) gastric tumors expressed GR, and its expression was prominent in elevated-type tumor with an intestinal histologic feature. Of 28 patients who underwent eradication therapy, 9 showed gastric tumors that became flat or depressed. In these 9 cases, GR expression was detected in all tumors, and the decrease in gastrin levels was more prominent than in those without morphological change (p = 0.01). CONCLUSION: The gastrin-GR system plays an important role in the elevated morphology of gastric tumors.

Evaluation of gastric cancer risk using topography of histological gastritis: a large-scaled cross-sectional study.

We evaluated the topography of histological gastritis, which may be risk factors for gastric cancer (GCa). A total of 530 Helicobacter pylori-positive patients underwent diagnostic upper-gastrointestinal endoscopy. Biopsy specimens were obtained from the gastric antrum and body to assess the grade of gastritis. Subjects were divided into four groups by the topography of active gastritis (antrum predominant gastritis, AP; pan-gastritis with or without corpus atrophy, Pan-1 and Pan-2; and corpus predominant gastritis, CP). A higher prevalence of GCa followed the order of Pan 2-->CP-->Pan 1-->AP. The age of patients decreased in the same order. When we set Pan 2 and CP as a high-risk group, the sensitivity and specificity for GCa detection were 77.3 and 54.7%, which were superior to the serum criteria using pepsinogens. These suggest that topography of histologic gastritis is an important marker to identify the high-risk group.