Helicobacter pylori is a human microbial pathogen that colonizes the gastric epithelium and causes type B gastritis with varying degrees of active inflammatory infiltrates. The underlying chronic inflammation induced by H. pylori and other environmental factors may promote the development of neoplasms and adenocarcinoma of the stomach. Dysregulation of various cellular processes in the gastric epithelium and in different cells of the microenvironment is a hallmark of H. pylori infection. We address the conundrum of H. pylori-associated apoptosis and review distinct mechanisms induced in host cells that either promote or suppress apoptosis in gastric epithelial cells, often simultaneously. We highlight key processes in the microenvironment that contribute to apoptosis and gastric carcinogenesis.

Immune checkpoint blockade using PD-1 inhibition is an effective approach for treating a wide variety of cancer subtypes. While lower gastrointestinal (GI) side effects are more common, upper gastrointestinal adverse events are rarely reported. Here, we present a case of nivolumab-associated autoimmune gastritis. To elucidate the immunology underlying this condition, we leverage multiplexed ion beam imaging by time-of-flight (MIBI-TOF) to identify the presence and proportion of infiltrating immune cells from a single section of biopsy specimen. Using MIBI-TOF, we analyze formalin-fixed, paraffin-embedded human gastric tissue with 28 labels simultaneously. Our analyses reveal a gastritis characterized by severe mucosal injury, interferon gamma (IFN-γ)-producing gastric epithelial cells, and mixed inflammation that includes CD8 and CD4 T cell infiltrates with reduced expression of granzyme B and FOXP3, respectively. Here, we provide a comprehensive multiplexed histopathological mapping of gastric tissue, which identifies IFN-γ-producing epithelial cells as possible contributors to the nivolumab-associated gastritis.

Whereas cancer patients have benefited from liquid biopsies, the scenario for gastric adenocarcinoma (GAC) is still dismal. We used next-generation deep sequencing of TP53-a highly mutated and informative gene in GAC-to assess mutations in tumor biopsies, plasma (PL) and stomach fluids (gastric wash-GW). We evaluated their potential to reveal tumor-derived mutations, useful for monitoring mutational dynamics at diagnosis, progression and treatment. Exon-capture libraries were constructed from 46 patients including tumor biopsies, GW and PL pre and post-treatment (196 samples), with high vertical coverage >8,000×. At diagnosis, we detected TP53 mutations in 15/46 biopsies (32.6%), 7/46 GW- (15.2%) and 6/46 PL-samples (13%). Biopsies and GW were concordant in 38/46 cases (82.6%) for the presence/absence of mutations and, furthermore, four GW-exclusive mutations were identified, suggesting tumor heterogeneity. Considering the combined analysis of GW and PL, TP53 mutations found in biopsies were also identified in 9/15 (60%) of cases, the highest detection level reported for GAC. Our study indicates that GW could be useful to track DNA alterations, especially if anchored to a comprehensive gene-panel designed for this malignancy.

Nowadays, gastric ulcers have become very common gastrointestinal disorders and numerous natural plant extracts exert promising anti-ulcerative effects. Therefore, this study was designed to evaluate the possible protective effect of dietary starch against ethanol induced gastric ulcers in mice. Post-administration of dietary starch for three consecutive days caused remarkable ameliorations in hemorrhagic lesions in gastric mucus and significant suppression in % incidence of ulceration, ulcer index and ulcer score induced by ethanol single administration. Indeed, deep ulceration, necrosis, disruption and degeneration in large areas of mucosa layer together with dense inflammatory cells infiltration and edema in sub-mucosal layer induced by ethanol administration were attenuated by starch post-administration and normalized the tissue architecture of the stomach. This potential protective effect could be attributed to the potent anti-oxidative capacity of starch that causes scavenger of the reactive oxygen species and thereby decreasing single and double DNA stranded break inductions and apoptotic DNA damage revealed by returning the p53 and caspase-3 expression levels to the normal level compared to the ethanol treated group. In conclusion, dietary starch has a potent therapeutic effect against ethanol induced gastric ulcer in mice via its free radical scavengers ability. Thus, we recommended further studies on its possible use as antiulcer drugs.

The gastric hormone gastrin plays a role in organizing the gastric mucosa. Gastrin also regulates the expression of genes that have important actions in extracellular matrix modelling, including plasminogen activator inhibitor (PAI)-1 which is part of the urokinase plasminogen activator (uPA) system. The uPA system (including PAI-1) is associated with cancer progression, fibrosis and thrombosis. Its biological role in the stomach and molecular mechanisms of action are not well understood. The aim of this study was to examine the effect of PAI-1 on the trophic changes observed in gastric corpus mucosa in hypergastrinemia using PAI-1 and/or HK-ATPase beta subunit knockout (KO) mice. HK-ATPase beta subunit KO mice were used as a model of hypergastrinemia. In 12 month old female mice, intragastric acidity and plasma gastrin were measured. The stomachs were examined for macroscopic and histological changes. In mice null for both PAI-1 and HK-ATPase beta (double KO), there was exaggerated hypergastrinemia, increased stomach weight and corpus mucosal thickness, and more pronounced trophic and architectural changes in the corpus compared with HK-ATPase beta KO mice. Genome-wide microarray expression data for the gastric corpus mucosa showed a distinct gene expression profile for the HK-ATPase beta KO mice; moreover, enrichment analysis revealed changes in expression of genes regulating intracellular processes including cytoskeleton remodelling, cell adhesion, signal transduction and epithelial-to-mesenchymal transition (EMT). Genes differentially expressed in the double KO compared with HK-ATPase beta KO mice included the transcription factor Barx2 and the chromatin remodeler gene Tet2, which may be involved in both normal gastric physiology and development of gastric cancer. Based on the present data, we suggest that PAI-1 plays a role in maintaining gastric mucosal organization in hypergastrinemia.

P53, the most commonly mutated tumor suppressor gene in all types of human cancer, is involved in cell cycle arrest and control of apoptosis. Although p53 contains several polymorphic sites, the codon 72 polymorphism is by far more common. There are divergent reports but many studies suggest p53 pro/pro SNP may be associated with susceptibility to developing various cancers in different regions of the world. The present study aimed to find any correlation between H. pylori infection and progression of carcinogenesis, by studying apoptosis and the p53 gene in gastric biopsies from north Indian population.

A total of 921 biopsies were collected and tested for prevalence of H. pylori by rapid urease test (RUT), imprint cytology and histology. Apoptosis was studied by the TUNEL method. Analysis of p53 gene polymorphism at codon 72 was accomplished by PCR using restriction enzyme BstU1.

Out of 921 samples tested 56.7% (543) were H. pylori positive by the three techniques. The mean apoptotic index (AI) in the normal group was 2.12, while gastritis had the maximum 4.24 followed by gastric ulcer 2.28, gastropathy 2.22 and duodenal ulcer 2.08. Mean AI in cases with gastric cancer (1.72) was less than the normal group. The analysis of p53 72 SNP revealed that p53 (Arg/Arg), (Pro /Arg) variant are higher (40.59% and 33.66%) as compared to p53 pro/pro variant (25.74%) in the healthy population.

The North Indian population harbors Arg or Pro/Arg SNP that is capable of withstanding stress conditions; this may be the reason of low incidence of gastric disease in spite of high infection with H. pylori. There was no significant association with H. pylori infection and AI. However, there is increased apoptosis in gastritis which may occur independent of H. pylori or p53 polymorphism.

Long noncoding RNAs (lncRNAs) play a crucial role in tumorigenesis. However, the value of lncRNAs in the diagnosis of gastric cancer remains unknown. To identify whether lncRNA-AA174084 is a potential marker for the early diagnosis of gastric cancer (GC), the authors investigated its levels in tissues, blood, and gastric juices from patients with various stage of gastric tumorigenesis.

Total RNA in 860 specimens from patients and healthy controls was extracted. Levels of AA174084 in 134 paired GC tissues, 127 gastric mucosal tissues, 335 plasma samples, and 130 gastric juice samples at each stage of gastric tumorigenesis were measured using real-time reverse transcriptase-polymerase chain reaction analysis. The potential association between AA174084 levels and patients' clinicopathologic features were analyzed. A receiver operating characteristic (ROC) curve was constructed for differentiating GC patients from controls.

Expression levels of AA174084 were down-regulated significantly in 95 of 134 GC tissues (71%) compared with the levels in paired, adjacent, normal tissues (P < .001). AA174084 levels had significant, negative correlations with age (P = .031), Borrmann type (P = .016), and perineural invasion (P = .032). Plasma AA174084 levels in patients with GC dropped markedly on day 15 after surgery compared with preoperative levels (P < .001) and were associated with invasion (P = .049) and lymphatic metastasis (P = .042). AA174084 levels in gastric juice from patients with GC were significantly higher than the levels in normal mucosa or in patients with minimal gastritis, gastric ulcers, and atrophic gastritis (P < .001). The area under ROC was up to 0.848 (P < .001).

AA174084 may have potential as marker for the early diagnosis of GC.

A number of pathogenic bacteria target mitochondria to modulate the host's apoptotic machinery. Studies here revealed that infection with the human gastric pathogen Helicobacter pylori disrupts the morphological dynamics of mitochondria as a mechanism to induce host cell death. The vacuolating cytotoxin A (VacA) is both essential and sufficient for inducing mitochondrial network fragmentation through the mitochondrial recruitment and activation of dynamin-related protein 1 (Drp1), which is a critical regulator of mitochondrial fission within cells. Inhibition of Drp1-induced mitochondrial fission within VacA-intoxicated cells inhibited the activation of the proapoptotic Bcl-2-associated X (Bax) protein, permeabilization of the mitochondrial outer membrane, and cell death. Our data reveal a heretofore unrecognized strategy by which a pathogenic microbe engages the host's apoptotic machinery.

Although gastric cancer (GCa) is strongly associated with Helicobacter pylori infection, only some H. pylori-positive subjects develop gastric cancer. The aim of this study is to identify H. pylori-positive subjects at high risk of developing GCa by assessment of the histopathological findings in the non-cancer-containing mucosa of patients with and without GCa. The subjects were 35 patients with diffuse-type gastric cancer (D-GCa), 55 with intestinal-type gastric cancer (I-GCa), and 99 H. pylori-positive controls without GCa. Two specimens were taken from the greater curvature of the antrum and the middle body. Histopathological gradings were evaluated using the updated Sydney System, and the risk of GCa was evaluated using a modified Meining's gastric cancer risk index (GCRI). Among the H. pylori-positive controls, corpus gastritis was seen in 98.0% (97/99) and corpus atrophic gastritis in 78.8% (78/99). The mean GCRI for the D-GCa (5.514±2.03) and I-GCa (6.836±2.08) groups was significantly greater than that for the H. pylori-positive controls (4.071±2.07; p=0.0005, p<0.0001). In addition, the mean GCRI for the I-GCa group was significantly greater than that for the D-GCa group (p<0.005). The GCRI-positive rate was significantly higher in subjects with GCa than in H. pylori-positive controls (D-GCa: p<0.005, I-GCa: p<0.0001). Many H. pylori-positive Japanese still carry a high risk for gastric cancer. However, H. pylori-positive patients at high risk of developing GCa (not only intestinal-type but also diffuse-type) may be detected using a simple GCRI.

Emerging evidence reveals that pattern-recognition receptors (PRRs), Toll-like receptors (TLRs), and nucleotide-binding oligomerization domain proteins (NODs) mediate both infection-induced and sterile inflammation by recognizing pathogen-associated molecular patterns and endogenous molecules, respectively. PRR-mediated chronic inflammation is a determinant for the development and progression of chronic diseases including cancer, atherosclerosis, and insulin resistance. Recent studies demonstrated that certain phytochemicals inhibit PRR-mediated pro-inflammation. Curcumin, helenalin, and cinnamaldehyde with α, β-unsaturated carbonyl groups, or sulforaphane with an isothiocyanate group, inhibit TLR4 activation by interfering with cysteine residue-mediated receptor dimerization, while resveratrol, with no unsaturated carbonyl group, did not. Similarly, curcumin, parthenolide, and helenalin, but not resveratrol and (-)-epigallocatechin-3-gallate (EGCG), also inhibit NOD2 activation by interfering with NOD2 dimerization. In contrast, resveratrol, EGCG, luteolin, and structural analogs of luteolin specifically inhibit TLR3 and TLR4 signaling by targeting TANK binding kinase 1 (TBK1) and receptor interacting protein 1 (RIP1) in Toll/IL-1 receptor domain-containing adaptor inducing IFN-β (TRIF) complex. Together, these results suggest that PRRs and downstream signaling components are molecular targets for dietary strategies to reduce PRR-mediated chronic inflammation and consequent risks of chronic diseases.

Atrophic gastritis, is the main consequence of long-standing Helicobacter pylori infection, and is linked to the development of gastric cancer. The severity of atrophic gastritis is related to the lifetime risk of gastric cancer development, especially in terms of its degree and extent of mucosal damage. Therefore, it is important for clinicians to assess the severity of atrophic gastritis, interfere with the disease progress, and reverse gastric mucosal atrophy. In the article, we demonstrated some methods (conventional endoscopy, modern endoscopic technology and noninvasive methods) that may help assess the severity of atrophic gastritis and select the reasonable treatment protocols.

Gastric cancer is one of the most common malignancies in the world; however, its exact mechanism of development which may be relevant to many factors is still unclear, such as age, diet, Helicobacter pylori infection, smoking, polyps, chronic gastric ulcer and so on. Chronic gastric ulcer is considered as precancerous lesion of gastric cancer. The above-mentioned diseases are usually diagnosed by endoscopy and biopsy. In general, biopsy specimens are usually taken from the edges of lesions, seldom from the base. In patients with chronic gastric ulcer, especially healing or healed benign ulcer, we took the biopsy specimens from both the edges and the base of ulcers in the follow-up. Malignant lesions were found in several cases of chronic gastric ulcer, in which specimens were taken from the base of lesions. Therefore, we hypothesize that biopsy from the base of healing or healed chronic gastric ulcer in the second or third endoscopy may find gastric cancer earlier than traditional biopsy.

The discovery that Helicobacter pylori is associated with gastric cancer has led to numerous studies that investigate the mechanisms by which H. pylori induces carcinogenesis. Gastric cancer shows genetic instability both in nuclear and mitochondrial DNA, besides impairment of important DNA repair pathways. As such, this review highlights the consequences of H. pylori infection on the integrity of DNA in the host cells. By down-regulating major DNA repair pathways, H. pylori infection has the potential to generate mutations. In addition, H. pylori infection can induce direct changes on the DNA of the host, such as oxidative damage, methylation, chromosomal instability, microsatellite instability, and mutations. Interestingly, H. pylori infection generates genetic instability in nuclear and mitochondrial DNA. Based on the reviewed literature we conclude that H. pylori infection promotes gastric carcinogenesis by at least three different mechanisms: (1) a combination of increased endogenous DNA damage and decreased repair activities, (2) induction of mutations in the mitochondrial DNA, and (3) generation of a transient mutator phenotype that induces mutations in the nuclear genome.

Intestinal type gastric cancer is a significant cause of mortality, therefore a better understanding of its molecular basis is required. We assessed if either aneuploidy or activity of the oncogenic transcription factor nuclear factor kappa B (NF-kappaB), increased incrementally during pre-malignant gastric histological progression and also if they correlated with each other in patient samples, as they are both induced by oxygen free radicals. In a prospective study of 54 (aneuploidy) and 59 (NF-kappaB) consecutive patients, aneuploidy was assessed by interphase fluorescent in situ hybridisation (FISH) for chromosome 1. NF-kappaB was assessed by expression of interleukin-8 (IL-8), and in a subset, by immunohistochemistry (IHC) for active p65. Aneuploidy levels increased incrementally across the histological series. 2.76% of cells with normal histology (95% CI, 2.14-3.38%) showed background levels of aneuploidy, this increased to averages of 3.78% (95% CI, 3.21-4.35%), 5.89% (95% CI, 3.72-8.06%) and 7.29% (95% CI, 4.73-9.85%) of cells from patients with gastritis, Helicobacter pylori positive gastritis and atrophy/intestinal metaplasia (IM) respectively. IL-8 expression was only increased in patients with current H. pylori infection. NF-kappaB analysis showed some increased p65 activity in inflamed tissues. IL-8 expression and aneuploidy level were not linked in individual patients. Aneuploidy levels increased incrementally during histological progression; were significantly elevated at very early stages of neoplastic progression and could well be linked to cancer development and used to assess cancer risk. Reactive oxygen species (ROS) induced in early gastric cancer are presumably responsible for the stepwise accumulation of this particular mutation, i.e. aneuploidy. Hence, aneuploidy measured by fluorescent in situ hybridisation (FISH) coupled to brush cytology, would be worthy of consideration as a predictive marker in gastric cancer and could be clinically useful in pre-malignant disease to stratify patients by their cancer risk.

We recently reported the expansion of the acid-secreting mucosa following Helicobacter pylori eradication with Congo red chromoendoscopy for a short-term follow-up of up to 7 months. We aimed to extend the observation period and to clarify the characteristic features of acid-secreting and non-acid-secreting mucosa.

In 24 H. pylori-positive patients with fundic atrophy, Congo red chromoendoscopy was performed prior to, 1 month, 7 months, and finally more than 2 years after the eradication. The areas of the acid-secreting mucosa were evaluated semiquantitatively. Two gastric biopsy specimens were taken from the acid-secreting and non-acid-secreting areas at the final chromoendoscopy and were subjected to histologic evaluation and immunohistochemistry for Ki-67 as a proliferation index.

After a gradual increase in acid-secreting areas for up to 7 months after eradication, they further increased in 79% subjects between 7 months and the final observation at a mean follow-up of 62 months. However, there still existed non-acid-secreting mucosa in the fundic area in all subjects, indicating that the expansion of acid-secreting mucosa remained partial. Compared with the neighboring acid-secreting area, the non-acid-secreting area was characterized histologically by higher degrees of residual inflammation, mucosal atrophy, and intestinal metaplasia, and by sustained hyperproliferation as well.

Functionally irreversible (non-acid-secreting) gastric mucosa after eradication was associated with extensive intestinal metaplasia and sustained hyperproliferation, suggesting that such mucosa still possesses malignant potential. Congo red chromoendoscopy may be useful for estimating the risk of subsequent development of gastric cancer following successful H. pylori eradication by determining the distribution of functionally irreversible mucosa.

Long-term therapy with potent acid inhibitors is a common treatment for gastro-esophageal reflux disease. Administration of proton pump inhibitors (PPIs) causes profound and continuous hypochlorhydria by inhibition of the proton pump in gastric parietal cells. Long-term hypergastrinaemia increases mucosal thickness and enterochromaffin-like cell density in oxyntic mucosa.

The aim of this study was to see whether this very common clinical intervention induces significant changes in the gastric mucosal gene expression pattern.

Seven patients suffering from gastro-esophageal reflux disease were included in this study. Endoscopic biopsies were taken from the corpus mucosa before and toward the end of a 3-month treatment with the PPI esomeprazole.

Microarray analysis identified 186 differentially expressed genes. A high proportion of genes with changed gene expression levels during PPI treatment are involved in proliferation, apoptosis, and stress response.

This study identified many genes that were not previously known to be affected by inhibition of gastric acid secretion. Further characterization of the functional roles of genes whose expression is modulated by potent acid inhibition may give new insight into the biological responses to potent acid inhibition, including the mucosal response to the moderately increased gastrin levels encountered in clinical practice.

To examine the significance of alteration of p53-regulated apoptosis-induced protein 1 (p53AIP1) expression in gastric carcinogenesis in patients with Helicobacter pylori infection.

H. pylori infection induces gastric mucosal inflammation and DNA damage of epithelial cells, which associate with gastric carcinogenesis. p53AIP1 is expressed after DNA damage and induces apoptosis in human cell lines.

Endoscopic antral and corpus biopsies were obtained from 13 patients with chronic gastritis and 17 with gastric cancer. Expression of p53AIP1 and p53DINP1 mRNA was examined by semiquantitative reverse transcription polymerase chain reaction and mutation of p53 codon-46 was studied by direct sequence analysis. The grade of gastritis was assessed according to the updated Sydney System. Results were compared between patients with gastric cancer and chronic gastritis.

In the antrum, p53AIP1 mRNA expression was significantly lower in patients with gastric cancer than in those with chronic gastritis (P<0.05). In patients with chronic gastritis, expression of p53AIP1 mRNA was significantly higher in the antrum than in the corpus (P<0.05). In patients with chronic gastritis, antral mucosa with high p53AIP1 expression tended to have severe intestinal metaplasia. No mutation was found at p53 codon-46.

In H. pylori-infected gastric mucosa expression of p53AIP1 would be higher when the inflammation is severe or intestinal metaplasia is present. Insufficient expression of p53AIP1 may play a role in gastric carcinogenesis in patients infected with H. pylori infection.

Helicobacter pylori vacuolating cytotoxin A (VacA) has been considered as an apoptosis-inducing factor. Here, we investigated the mechanism of VacA-induced apoptosis in relation to the defense mechanism and MAP kinases pathway in gastric epithelial cells. AGS cells exposed to enriched VacA extracts affected the level of SOD-1 and villin. We further investigated the role of VacA in those inductions using a functional recombinant VacA (rVacA). Activation of p38 MAPK and Bax dimerization by rVacA were increased in a dose-dependent manner. rVacA-induced ERK1/2 MAPK activation was maximal at 30 min and 4 h and 1-4 microg/ml of rVacA. rVacA-induced SOD-1 expression was considerably diminished by inhibiting ERK1/2 MAPK and it was slightly increased by inhibiting p38 MAPK. rVacA increased or decreased villin expression depending on dose and exposure time and its expression was mainly appeared in the contractile actin ring of the dividing cells. Despite its cytoprotective effect, SB-203580, a p38 inhibitor, was unlikely to reduce VacA-induced Bax dimerization and rather inhibited villin and Bcl2 expression, indicating that p38 may also play a role in cell proliferation or differentiation for survival after VacA intoxication. Furthermore, p38 inhibitor accelerated rVacA-induced cell death after exposure of AGS cells to H(2)O(2) but ERK1/2 inhibitor protected cells from H(2)O(2) insult. These results suggest that SOD-1 and villin are expressed differentially upon VacA insult depending on dose and exposure time via ERK and p38 MAP kinases; decrease in SOD-1 and villin expression coupled with Bax dimerization leads to apoptosis of gastric epithelial cells.

To investigate epithelial cell turnover alterations, and p53, bcl-2 protein expression during development of early and advanced gastric cancer in a Western population.

We investigated cell apoptosis and proliferation rates, p53 and bcl-2 protein expression in 17 early and 34 advanced gastric carcinomas and in the adjacent non-dysplastic mucosa. Cell proliferation, p53 and bcl-2 expression were detected immunohistochemically using MIB-1, anti-p53 and anti-bcl-2 monoclonal antibodies. Apoptosis was measured by TUNEL. The rate of the positive stained cells (labelling index) was count using image analysis technique.

No difference was observed of either apoptotic (10 vs. 11) or proliferation (35 vs. 25) index between early and advanced cancers. However, the apoptotic index was significantly higher in intestinal type advanced tumors. While both apoptotic and proliferation indices were significantly higher in tumors than in the adjacent mucosa, no difference was observed of either apoptotic (2 vs. 2) or proliferation (8 vs. 13) index between the tissues adjacent to early and advanced tumors. p53 protein expression was significantly higher in advanced cancers (7 vs. 5, p=0.001) and in the non-dysplastic tissue adjacent to advanced tumors (3.5 vs. 2, p=0.001). bcl-2 labelling index was significantly higher in the mucosa adjacent to advanced carcinomas (15 vs. 5, p=0.016) but this difference did not reach significance in the tumors (20 vs. 15, p=0.37).

Our data indicate similar cell turnover during tumorigenesis of early and advanced cancer. p53 and bcl-2 protein accumulation is more intense in gastric mucosa adjacent to advanced tumors and p53 immunoreactivity peaks in advanced carcinomas.

To study the effect of proton pump inhibitor (PPI) treatment on patients with reflux esophagitis and its in vivo effect on apoptosis, p53- and epidermal growth factor receptor (EGFR) expression.

After informed consent was obtained, gastric biopsies of the antrum were taken from patients with reflux oesophagitis prior to and after 6 mo of 20 mg omeprazole (n = 14) or 40 mg esomeprazole (n = 12) therapy. Patients did not take any other medications known to affect the gastric mucosa. All patients were Helicobacter pylori negative as confirmed by rapid urease test and histology, respectively. Cell proliferation, apoptosis, EGFR, and p53 expression were measured by immunohistochemical techniques. At least 600 glandular epithelial cells were encountered and results were expressed as percentage of total cells counted. Was considered statistically significant.

Although there was a trend towards increase of cell proliferation and EGFR expression both in omeprazole and esomeprazole treated group, the difference was not statistically significant. Neither apoptosis nor p53 expression was affected.

Long-term PPI treatment does not significantly increase gastric epithelial cell proliferation and EGFR expression and has no effect on apoptosis and p53 expression.

Chronic gastritis with gastric mucosa atrophy, intestinal metaplasia and endocrine cell hyperplasia are alterations with an increased risk for the development of gastric neoplasias. Immunological studies in autoimmune gastritis, in atrophic Helicobacter pylori gastritis and in studies with transgenic mice point to a central role of the parietal cell in the development of gastric mucosa atrophy. Destruction of gastric epithelial cells alone might not be sufficient for the loss of complete gastric glands. Gastric atrophy, endocrine cell hyperplasia and intestinal and pancreatic metaplasia can be regarded as the result of altered morphogenesis within the gastric mucosa. Impaired expression of the gastric morphogenic factor Sonic Hedgehog by parietal cells and increased expression of the transcriptional activators of intestinal and pancreatic differentiation, namely CDX2 and PDX1, seem to be crucial for the development of gastric atrophy and for intestinal, endocrine and pancreatic transdifferentiation processes. Altered expression of these morphogenic factors is partly caused by changes in the gastric milieu. Further studies concerning the normal and pathological morphogenesis of the gastric mucosa and related tissues might give new insight into the pathogenesis of gastric atrophy and metaplasia.

Helicobacter pylori (H. pylori) colonizes the gastric mucosa of a half of the mankind. Duodenal ulcer is found in 15-25%, gastric ulcer in 13%, while gastric adenocarcinoma develops in 1% of all infected individuals. Pathogenesis of H. pylori infection is related to the virulence factors of the bacterium, environmental (dietary habits, hygiene, stress) and host factors (age, sex, blood type). Colonization of the gastric mucosa is related to the motility of the bacterium, presence of lipopolysaccharide (LPS) and various bacterial enzymes. Gastric mucosal injury is the result of H. pylori LPS, vacuolization cytotoxin (vacA), cytotoxin associated protein (cagA), heat shock proteins and factors responsible for neutrophil chemotaxis and activity. H. pylori colonizes the gastric mucosa and zones of ectopic gastric epithelium. H. pylori infection is transmitted via oral-oral, fecal-oral and iatrogenic way (during endoscopy). Higher prevalence of the infection is associated with lower socioeconomic level, lack of drinking water, and living in a community. Acute H. pylori gastritis is superficial pangastritis progressing into the chronic phase after 7-10 days. Gastric mucosal atrophy and intestinal metaplasia can develop during the course of H. pylori infection. Clearly defined factors that influence the outcome of H. pylori infection include bacterial strain, distribution of gastritis, acid secretion and gastric mucosal atrophy.

Although Helicobacter pylori infection is now acknowledged as a major promoter of gastric cancer in humans, the carcinogenetic process of this effect has not been fully elucidated. Precancerous lesions such as intestinal metaplasia, enhanced proliferation of epithelial cells and elevated level of growth factors have been postulated to play a role.

To analyse a relationship between gastric mucosal proliferation, mucosal content of hepatocyte growth factor and prevalence of intestinal metaplasia before and after successful H. pylori eradication therapy.

We evaluated 25 H. pylori-eradicated patients. At initial endoscopic examination, two biopsy tissue samples each were obtained from the antrum and great curvature of the corpus. Tissue content of hepatocyte growth factor and neutrophil myeloperoxidase were measured using an ELISA method, and histological assessment of intestinal metaplasia (haematoxylin and eosin) and proliferating cells (Ki-67 immunostaining) was performed. The patients were treated with a 1-week course of triple therapy. At 10 months after successful eradication, biochemical and histological assessments were repeated.

Among all patients (n = 25), no intestinal metaplasia was detected in the corpus mucosa, but was observed in 10 patients (40%) in the antrum. This prevalence ratio was not changed after eradication. A slight decrease in HGF content was demonstrated in both sites, but the level of antral hepatocyte growth factor was significantly decreased in patients with intestinal metaplasia but not in those without. Proliferative index (Ki-67 positive cells/epithelium) was decreased after eradication therapy in both sites. An increase in proliferative index was observed in the antrum with intestinal metaplasia compared with that without, which significantly decreased after eradication therapy.

H. pylori eradication therapy in the present study afforded an inhibitory effect on epithelial cell proliferation and on the mucosal content of HGF.

Helicobacter pylori infection in gastric mucosa is a form of chronic active gastritis that leads to expression of inducible nitric oxide synthase in host macrophages and polymorphonuclear leukocytes. Nitric oxide produced by these cells infiltrating the gastric mucosa could damage DNA. We correlated apoptosis in H. pylori-infected antral tissue from peptic ulcer patients with serum nitrate-plus-nitrite.

Biopsy specimens were obtained endoscopically from antrum and fundus in 17 peptic ulcer patients before and after H. pylori eradication. Tissue samples were subjected to rapid urease testing and histopathological scoring (updated Sydney system), as well as immunohistochemical detection of single-stranded DNA indicating apoptotic cells. Fasting serum samples were analyzed for combined nitrate and nitrite content.

In all cases atrophy was absent to mild in antral mucosa and H. pylori was eradicated successfully. A strong positive correlation was present between apoptosis and both inflammation and activity scores in infected antral mucosa. A significant positive correlation also was noted between apoptosis and H. pylori density. Serum nitrite concentrations were decreased significantly by successful eradication of H. pylori, and showed a strong positive correlation with H. pylori density. Serum nitrite concentrations showed a significant positive correlation with numbers of single-stranded DNA-positive cells.

High H. pylori density was associated with elevated serum nitrate-plus-nitrite (a marker of nitric oxide production in gastric mucosa). Increased apoptosis and abnormal gastric cell turnover are likely results.

The biological processes involved in the development of gastric mucosal atrophy and intestinal metaplasia are still incompletely understood. Reports testing the hypothesis that apoptosis leads to atrophy have yielded conflicting results. The availability of new antibodies for the detection of apoptotic cells in tissue sections has facilitated the analysis of the role of apoptosis in the gastritis-atrophy-intestinal metaplasia sequence.

Archival material from 40 gastric resection specimens with normal mucosa (n = 5), chronic active gastritis (n = 17), or intestinal metaplasia (n = 18) was studied. Immunohistochemistry was performed using antibodies directed against cleaved cytokeratin 18 and active caspase 3. Slides were scored on a 0-3 scale for the presence of apoptotic cells.

Normal gastric mucosa contained low numbers of apoptotic cells at the surface epithelium (mean score, 0.20). This number was significantly increased in cases with chronic gastritis (mean score, 1.06) and in those with intestinal metaplasia (mean score, 2.56). Within the intestinal metaplasia cases, 44 different foci of intestinal metaplasia were identified. In 39 of these 44 areas, concentrations of apoptotic cells were seen immediately adjacent to the foci of intestinal metaplasia, but not in the metaplastic epithelium itself.

Apoptosis is uncommon in normal gastric mucosa. Chronic inflammation and intestinal metaplasia are associated with increased apoptosis, but occur mainly at the mucosal surface and not in the deeper layers. These findings do not support the concept that apoptosis underlies the loss of gastric glands and leads to atrophy, but the observed concentration of apoptotic epithelial cells adjacent to foci of intestinal metaplasia could be related to heterogeneity of epithelial damage, causing apoptosis, to which intestinal metaplasia is a response.

Helicobacter pylori induces the apoptosis of gastric epithelial cells in vivo and in vitro. However, the molecular mechanism has not been clarified. The aim of this study was to investigate the effect of H pylori on the apoptosis of gastric epithelial cells and the expression of apoptosis related genes in vitro.

Human gastric adenocarcinoma SGC-7901 cells were co-cultured with a cytotoxic H pylori strain, NCTC 11637, at various densities ranging from 3.2 x 10(4) to 1.0 x 10(8) colony forming units (CFU)/ml for 48 hours. Apoptosis in gastric cells was determined by transmission electron microscopy, Hoechst 33258 fluorochrome staining, and flow cytometry. The expression of apoptosis related proteins, Bcl-2, Bax, and c-Myc, was measured by an immunohistochemical method, and c-Myc mRNA expression was determined by the reverse transcription-polymerase chain reaction.

Helicobacter pylori induces morphological changes typical of apoptosis. Both fluorochrome staining and flow cytometry showed that the apoptotic index began to increase when H pylori were at a density of > 1.6 x 10(4) CFU/ml, and in a density dependent manner (p < 0.01; one way ANOVA). The expression of the Bax and c-Myc proteins and of c-Myc mRNA was increased, whereas Bcl-2 expression was decreased after co-culture for 48 hours.

Helicobacter pylori induced apoptosis in gastric epithelial cells is mediated by altered expression of the products of the Bcl-2, Bax, and c-Myc genes.

Helicobacter pylori blood group antigen binding adhesin (BabA) mediates bacterial adherence to human blood group antigens on gastric epithelium. Although strains harbouring babA2 were recently found to be associated with peptic ulcer and gastric cancer, the role of babA2 in cellular turnover, severity of gastritis, and premalignant changes is poorly understood.

We correlated H pylori babA2, vacuolating toxin (vacA), and cytotoxin associated gene A (cagA) genotypes with the severity of gastric inflammation and epithelial cell turnover in a group of Chinese patients from an area with a high incidence of gastric cancer.

H pylori isolates were obtained from 104 Chinese patients who participated in a gastric cancer prevention programme. Genotype variants of babA2, vacA, and cagA were determined by polymerase chain reaction. Antrum and corpus histopathology was examined according to the updated Sydney classification. Apoptosis was scored by terminal uridine deoxynucleotidyl nick end labeling (TUNEL) and proliferation by Ki-67 immunostaining.

Of the 104 patients, 102 (98.1%) harboured cagA(+) strains and all had vacA s1 genotype. The babA2(+) strains were found in 83 (79.8%) patients and were associated with higher lymphocytic infiltration (p=0.028), presence of glandular atrophy (odds ratio (OR) 7.5, 95% confidence interval (CI) 2.3-24.3), and intestinal metaplasia (OR 7.4, 95% CI 2.2-25.3) in the antrum. Increased epithelial proliferation was also noted in individuals infected with babA2(+) strains (p=0.025). Strains harbouring cagA(+)/vacA s1 genotypes lacked this association in the absence of babA2.

The presence of babA2(+) H pylori strains alone or in combination with cagA(+) and vacA s1 was associated with the presence of preneoplastic gastric lesions.

Helicobacter pylori (H. pylori) infection has been recognized to be a causal factor of gastritis, ulcers and gastric cancer in man. Using Mongolian gerbils (M. gerbils), which are suitable for an H. pylori infection animal model, we examined 1) how H. pylori infection, indomethacin and their combination affects the healing of gastric ulcers and whether or not such factors provoke a relapse of healed acetic acid ulcers; and 2) whether or not eradication of the bacteria with drugs at specified times after infection prevents the development of mucosal changes, including gastric adenocarcinoma. 1) H. pylori infection significantly delayed ulcer healing 4 weeks following infection. Indomethacin treatment showed a tendency to delay ulcer healing. Ulcer healing in H. pylori-infected M. gerbils was significantly delayed by indomethacin. H. pylori infection resulted in a relapse of healed ulcers from 1 to 6 months after infection, with a gradual increase in size. Omeprazole markedly prevented the ulcer relapse caused by H. pylori infection. 2) Four or 8 months after H. pylori inoculation, eradication was performed by concurrent treatment with omeprazole + clarithromycin. Immediately after treatment ended in both the 5 and 9 month groups, it was verified that H. pylori were completely eradicated. Autopsy performed 18 months after H. pylori inoculation revealed gastric hyperplastic polyps with erosive lesions and ulcers that were grossly visible; and atrophic gastritis, intestinal metaplasia, carcinoids, and adenocarcinomas were histologically observed in the non-treated control group. In animals eradicated after 4 months and autopsied after 18 months, however, such mucosal changes were not observed. In contrast, intestinal metaplasia and mucosal atrophy was observed in animals eradicated after 8 months and autopsied after 18 months. It was concluded that 1) H. pylori infection delayed the healing of preexisting gastric ulcers and resulted in the relapse of healed ulcers, yet indomethacin had little or no effect on ulcer healing or relapse; and 2) early eradication of H. pylori infection with drug therapy can prevent severe gastric mucosal changes, to include adenocarcinomas, in M gerbils.

Helicobacter pylori infection has been reported to induce various mucosal changes, including gastric adenocarcinoma, in Mongolian gerbils 62 weeks after inoculation. Using Mongolian gerbils, this study examined whether or not eradication of the bacteria with drugs at specified times after infection prevents the development of mucosal changes. After orally inoculating with H. pylori (TN2GF4, vacA- and cagA-positive), the animals were killed 18 months later. Four or 8 months after H. pylori inoculation, eradication was performed by concurrent treatment with omeprazole+clarithromycin. Immediately after treatment ended, in both the 5 and 9 month groups, it was verified that H. pylori was completely eradicated. Autopsy performed 18 months after H. pylori inoculation revealed gastric hyperplastic polyps with erosive lesions and ulcers that were grossly visible in the non-treated control group. In addition, atrophic gastritis, intestinal metaplasia, carcinoids, and adenocarcinomas were histologically observed in the animals. In animals eradicated after 4 months and autopsied after 18 months, however, such mucosal changes were not observed. In contrast, intestinal metaplasia and mucosal atrophy was observed in animals eradicated after 8 months and autopsied after 18 months. It was concluded that early eradication of H. pylori infection with drug therapy can prevent severe gastric mucosal changes, to include adenocarcinomas, in Mongolian gerbils.