Correlation between epithelial cell proliferation and histological grading in gastric mucosa

Multiplexed imaging reveals an IFN-γ-driven inflammatory state in nivolumab-associated gastritis

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.

Long-term effect of Helicobacter pylori eradication combined with folate in patients with chronic atrophic gastritis

AIM

To investigate the long-term effect of Helicobacter pylori (H. pylori) eradication combined with folate in patients with chronic atrophic gastritis (CAG).

METHODS

One hundred and twenty-three patients who underwent H. pylori eradication from July 2013 to June 2014 at our hospital were enrolled and divided into a combination group (n = 71) and a single eradication group (n = 52). Patients in the single eradication group were given standard triple H. pylori eradication therapy, and cases in the combination group were given folate for 3 mo after H. pylori eradication. All cases were followed at 2 years after treatment. The stages of operative link for gastric intestinal metaplasia assessment (OLGIM) and operative link for gastritis assessment (OLGA) were compared between the two groups before and after treatment. Patients in the combination group were further divided into an H. pylori successful eradication group (n = 49) and an H. pylori reinfection group (n = 22) according to the result of ¹³C urea breath test, and CAG lesion score was compared among the three groups before and after treatment.

RESULTS

The stages of OLGIM and OLGA in the combination group were significantly better than those in the single eradication group at 2 years after treatment (P < 0.05). CAG lesion scores in the H. pylori successful eradication group and single eradication group at 2 years after treatment were significantly lower than those before treatment in the same group (P < 0.05), but there was no significant difference in CAG lesion score between before and after treatment in the H. pylori reinfection group (P > 0.05). After treatment, CAG lesion score in the H. pylori successful eradication group was significantly lower than those in the H. pylori reinfection group and single eradication group (P < 0.05), although there was no significant difference in CAG lesion score between the H. pylori reinfection group and single eradication group after treatment (P > 0.05).

CONCLUSION

H. pylori eradication combined with folate treatment could significantly improve gastric mucosal atrophy and intestinal metaplasia in patients with CAG, and promote disease recovery, with satisfactory long-term effect, especially for patients with successful H. pylori eradication.

Water-induced modulation of Helicobacter pylori virulence properties

While the influence of water in Helicobacter pylori culturability and membrane integrity has been extensively studied, there are little data concerning the effect of this environment on virulence properties. Therefore, we studied the culturability of water-exposed H. pylori and determined whether there was any relation with the bacterium’s ability to adhere, produce functional components of pathogenicity and induce inflammation and alterations in apoptosis in an experimental model of human gastric epithelial cells. H. pylori partially retained the ability to adhere to epithelial cells even after complete loss of culturability. However, the microorganism is no longer effective in eliciting in vitro host cell inflammation and apoptosis, possibly due to the non-functionality of the cag type IV secretion system. These H. pylori-induced host cell responses, which are lost along with culturability, are known to increase epithelial cell turnover and, consequently, could have a deleterious effect on the initial H. pylori colonisation process. The fact that adhesion is maintained by H. pylori to the detriment of other factors involved in later infection stages appears to point to a modulation of the physiology of the pathogen after water exposure and might provide the microorganism with the necessary means to, at least transiently, colonise the human stomach.

Disease manifestations of Helicobacter pylori infection in Arctic Canada: using epidemiology to address community concerns

OBJECTIVES

Helicobacter pylori infection, linked to gastric cancer, is responsible for a large worldwide disease burden. H pylori prevalence and gastric cancer rates are elevated among indigenous Arctic communities, but implementation of prevention strategies is hampered by insufficient information. Some communities in northern Canada have advocated for H pylori prevention research. As a first step, community-driven research was undertaken to describe the H pylori-associated disease burden in concerned communities.

DESIGN

Participants in this cross-sectional study completed a clinical interview and gastroscopy with gastric biopsies taken for histopathological examination in February 2008.

SETTING

Study procedures were carried out at the health centre in Aklavik, Northwest Territories, Canada (population ∼600).

PARTICIPANTS

All residents of Aklavik were invited to complete a clinical interview and gastroscopy; 194 (58% female participants; 91% Aboriginal; age range 10-80 years) completed gastroscopy and had gastric biopsies taken.

PRIMARY AND SECONDARY OUTCOME MEASURES

This analysis estimates the prevalence of gastric abnormalities detected by endoscopy and histopathology, and associations of demographic and clinical variables with H pylori prevalence.

RESULTS

Among 194 participants with evaluable gastric biopsies, 66% were H pylori-positive on histology. Among H pylori-positive participants, prevalence was 94% for acute gastritis, 100% for chronic gastritis, 21% for gastric atrophy and 11% for intestinal metaplasia of the gastric mucosa, while chronic inflammation severity was mild in 9%, moderate in 47% and severe in 43%. In a multivariable model, H pylori prevalence was inversely associated with previous gastroscopy, previous H pylori therapy and aspirin use, and was positively associated with alcohol consumption.

CONCLUSIONS

In this population, H pylori-associated gastric histopathology shows a pattern compatible with elevated risk of gastric cancer. These findings demonstrate that local concern about health risks from H pylori is warranted and provide an example of how epidemiological research can address health priorities identified by communities.

H. pylori eradication did not improve dysregulation of specific oncogenic miRNAs in intestinal metaplastic glands

BACKGROUND

Many microRNAs (miRNAs) are differentially expressed in Helicobacter pylori-infected gastric mucosa and in gastric cancer tissue.

AIM

We aimed to compare the effect of H. pylori eradication on gastric mucosal miRNAs in subjects in a high-risk group for gastric cancer compared to controls.

METHODS

Patients with a recent history of endoscopic resection for early gastric cancer and sex- and age-matched non-cancer controls were enrolled. The expression of 21 miRNAs was examined using gastric mucosal biopsy specimens and microdissected gastric glands from the lesser and greater curvatures of the gastric corpus both before and one year after H. pylori eradication.

RESULTS

Twenty patients and 14 controls were enrolled. The expression of oncogenic miRNAs (miR-17/92 and the miR-106b-93-25 cluster, miR-21, miR-194, and miR-196) was significantly higher in the gastric mucosa of the cancer group than in the controls. H. pylori eradication resulted in a significant fall in the expression of oncogenic miRNAs only in the controls, whereas miR-223 expression was decreased and let-7d expression was increased in both groups. miR-196 was expressed only in intestinal metaplastic glands. The expression of oncogenic miRNAs was significantly higher in the intestinal metaplastic glands than in the non-intestinal metaplastic glands irrespective of H. pylori eradication. In neither group did H. pylori eradication significantly change any miRNA expression in the intestinal metaplastic glands.

CONCLUSION

Dysregulation of specific miRNAs is present in H. pylori-induced corpus gastritis. H. pylori eradication improved miRNA dysregulation, but not in intestinal metaplastic glands or in the gastric mucosa of patients in a high-risk group for gastric cancer.

Bacterial load and degree of gastric mucosal inflammation in Helicobacter pylori infection

Helicobacter pylori induces an inflammatory immune response in the gastric mucosa. The degree of gastric mucosal inflammation and its topographic distribution are key factors in the diversity of H. pylori-related complications. Here we summarize substantial evidence reported in the literature concerning the impact of H. pylori density on gastric inflammation, the development of severe complications, and its relation to H. pylori suppression therapy. Most studies demonstrate a significant correlation between H. pylori density and the grade of acute and chronic inflammation, taking into account the limitations of each method for density assessment. Overall, high bacterial loads are associated with increased acute mucosal damage and long-term changes in the gastric mucosa. The influence of H. pylori density reduction on the improvement of gastric mucosal changes was observed in studies using 'clearance' therapies. Mucosal agents provoke a significant, but not persistent, reduction in gastritis activity. Treatments suppressing the density and virulence of H. pylori could become strategies to prevent H. pylori-associated disease in the future.

Histological evaluation of patients with gastritis at high risk of developing gastric cancer using a conventional index

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.

Helicobacter pylori infection generates genetic instability in gastric cells

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.

Immune response to Helicobacter pylori and its association with the dynamics of chronic gastritis in the antrum and corpus

The aim of the study was to establish possible factors which play a role in progression of gastritis to atrophic gastritis in long-term follow-up among the Estonian population, to assess the association between the host immune response and different Helicobacter pylori antigens and autoantigens in relation to the histological parameters of gastritis in the antrum and corpus. ELISA and immunoblot were used for detection of IgG to H. pylori acid glycine-extracted cell surface proteins, CagA protein, and H. pylori HSP60. Anticanalicular autoantibodies (ACAB) in the serum were evaluated according to Faller et al. (1996). Apoptosis was evaluated using the TUNEL method. Study subjects were 1958 persons from an unselected Estonian population, and 70 persons from a sample from Saaremaa Island, who had been investigated over a period of 18 years. Seropositivity for CagA was a sign of gastritis activity [OR=14.8 (4.5-50.3)] and atrophy [OR=7.0 (2.1-23.1)] and might predict development of atrophy, particularly in the corpus [OR=7.1 (1.8-27.7)]. The prevalence of ACAB increased significantly with duration of H. pylori gastritis from 22% in 1985 to 46% in 1997 (p=0.004). Immune response to H. pylori HSP60 indicates chronic inflammation in the antrum (p=0.003). Apoptosis of gastric epithelial cells is largely dependent on grade of activity of gastritis, and, particularly in the antrum, on grade of H. pylori colonization (p=0.01; p=0.02), but is not associated with development of atrophy. Seropositivity for different H. pylori antigens (CagA, HSP 60) serves as a marker of different histological manifestations in the antrum and corpus mucosa.

Immune and proliferative cellular responses to Helicobacter pylori infection in the gastric mucosa of Mexican children

BACKGROUND

Helicobacter pylori infection occurs mostly during childhood, but few studies on this age group have addressed the innate immune and the proliferative response to this infection. Mexico has a high H. pylori prevalence in children, but a low risk of gastric cancer. The aim of this work was to study the cellular responses of the gastric mucosa to this infection in Mexican children.

METHODS

Antral and corpus gastric biopsies were obtained from 44 H. pylori-infected children (mean age 12 +/- 3.2 years) and 44 uninfected children (mean age 10 +/- 3 years). Mucosal cellular responses were studied by immunohistochemistry, using anti-Ki67 antibodies for proliferation studies, antihuman tryptase for mast cells, and antihuman CD68 for macrophages. T and B lymphocytes were stained with a commercial integrated system. The intensity of cellular responses was estimated histologically using the software KS300.

RESULTS

Epithelium proliferation and infiltration of macrophages and T and B lymphocytes were significantly higher in H. pylori-infected than in uninfected children. A balanced increase of CD4, CD8, and CD20 lymphocytes was observed in infected children. However, activated mast cells were decreased, and infiltration of neutrophil and mononuclear cells was low. Epithelial proliferation was associated with polymorphonuclear infiltration but not with infiltration of macrophages or lymphocytes. Inflammation and proliferation was higher in CagA (+)-infected children.

CONCLUSIONS

Mexican children respond to H. pylori infection with a low inflammatory response, a balanced increase of T and B lymphocytes, and a high regenerative activity.

Gastric epithelial cell proliferation and cagA status in Helicobacter pylori gastritis at different gastric sites

OBJECTIVE

Helicobacter pylori infection causes hyperproliferation which is believed to predispose to the development of gastric carcinoma. The aim of this study was to analyze epithelial cell proliferation topographically in H. pylori gastritis in relationship to cagA status.

MATERIAL AND METHODS

The proliferative index (PI: Ki-67-labeled nuclei/total number of foveolar nuclei) was determined in gastric mucosa biopsies taken at the antrum (lesser and greater curvatures), incisura, and corpus (greater curvature) from 78 patients with H. pylori gastritis and 20 H. pylori-negative patients. H. pylori and cagA status were determined by polymerase chain reaction (PCR) and serology.

RESULTS

PIs were significantly higher in H. pylori- and cagA-positive patients, in comparison with H. pylori- and cagA-negative patients, at all sites (p<or=0.002 and p<or=0.009) and in the antrum in comparison to the corpus, in both H. pylori-negative (p=0.04) and positive patients (p<10(-3)). At the antral lesser curvature, PIs were higher than in all the other sites, both in H. pylori- (p<or=0.002) and cagA-positive groups (p<or=0.02). The PI correlated directly and significantly with inflammation in infected patients (r=0.45, p<10(-3)) and in cagA-positive patients (r=0.41, p=0.005). The PI was significantly higher in the antrum of infected patients with atrophy (p=0.03) and intestinal metaplasia (p=0.05) than in those without atrophy and intestinal metaplasia, respectively.

CONCLUSIONS

We demonstrated that H. pylori infection and cagA-positive strains promote epithelial proliferation that was correlated with host inflammatory reaction and mostly at the antral lesser curvature, which is recognized as the area where most carcinomas arise.

Gastric mucosal proliferative and total tyrosine kinases activities increase in Helicobacter pylori-induced chronic gastritis

BACKGROUND

The intestinal type of gastric cancer is thought to originate from cancer precursor lesions, progressing from H. pylori-induced chronic gastritis, atrophic gastritis, to intestinal metaplasia (IM) and dysplasia. Tyrosine kinases (tyr-k) represent the family of proteins that are widely expressed during cell metabolism and are considered as secondary markers for cellular proliferation and malignant transformation.

AIM OF STUDY

The aim of the study was to evaluate the correlation between gastric mucosal histopathologic changes, total tyrosine kinases, and proliferative activities in patients with H. pylori infection.

METHODS

Biopsy specimens from the gastric mucosa of 94 patients were assessed for H. pylori infection, histopathology (according to the Sydney classification), proliferative activity [Ki-67 immunohistochemistry with labeling index (LI) estimation], and total tyr-k activities (ELISA assay kit).

RESULTS

Total tyr-k activities and Ki-67 LI were significantly higher in H. pylori (+) than H. pylori (-) group (728.1 +/- 175.3 vs 360.1 +/- 44.4 pmol P/mg/min. p <0,01 and 20.0 +/- 5.8 vs 10.9 +/- 1.3 %, respectively). A significant correlation has been observed between the Ki-67 LI and total tyr-k activities in patients with and without H. pylori infection. In cases of gastritis accompanied with atrophic changes or intestinal metaplasia in H. pylori (+) patients, Ki-67 LI and total tyr-k activities were particularly high compared to chronic gastritis without atrophy or intestinal metaplasia.

CONCLUSION

Those results suggest that tyrosine kinases may play an important role in the development of gastric mucosal hyperproliferation in H. pylori-induced gastritis and possibly in early phase of gastric carcinogenesis.

Gastric and duodenal mucosal protein fractional synthesis and growth factor expression in patients with H. pylori-associated gastritis before and after eradication of the organism

Our purpose was to study the effect of Helicobacter pylori (HP) on mucosal protein fractional synthesis (MPFS) and growth factor expression. 14C-leucine incorporation, and TGF-alpha, beta-FGF, and EGF-receptor levels were assessed in gastric and duodenal mucosa in 20 patients with HP-associated gastritis and repeated after treatment of the gastritis, with or without eradication of the organism. At entry, MPFS in the fundus, antrum, and duodenum was 43.1, 38.2, and 28.3%/day, respectively. Following HP eradication, fundal and antral rates fell to 28.1 and 21.4%/day (P < 0.05), whereas the duodenum was unchanged. MPFS in the patient subset not eradicated remained similar to entry values (35.9, 31.6, and 25.4%/day). Expression of TGF-alpha, beta-FGF, and EGF receptors was unchanged. Eradication of HP results in reduction of gastric, but not duodenal, MPFS and has no effect on the growth factors measured. Increased MPFS associated with HP gastritis may relate to the potential for neoplastic transformation.

Prevention of gastric cancer by Helicobacter pylori eradication

The evidence supporting the important role of Helicobacter pylori causing gastric cancer is getting stronger. The mechanisms by which H. pylori can influence the progression to severe changes in the gastric mucosa are under investigation. An increased gastric epithelial cell proliferation has been observed in individuals infected with H. pylori. This lifelong increased cell turnover is deemed to be a major risk factor for increased mutational changes and may lead to the development of gastric cancer. Successful eradication of H. pylori infection induces the healing of the gastritis and a significant decrease in gastric epithelial cell proliferation. Nevertheless, it is right now unknown at which time the point of no return, meaning at which time an eradication therapy leads to a benefit for the individual to prevent gastric cancer, has been reached. Therefore the major question that arises is to whom an eradication therapy should be offered to prevent gastric cancer. A general elimination of the infection might be worthwhile, but seems to be unrealistic now because of the high prevalence of the infection and the missing of a vaccine. This review reflects possible mechanisms of gastric cancer development induced by chronic H. pylori infection and recent investigational trials for prevention of gastric cancer by H. pylori eradication therapy will be discussed.

Helicobacter-induced gastritis in mice not expressing metallothionein-I and II

BACKGROUND

Helicobacter pylori a primary cause of gastritis and peptic ulcer disease, is associated with increased production of reactive oxygen species within the gastric mucosa. Metallothionein (MT), a low-molecular-weight, cysteine-rich, metal-binding ligand, has been shown to sequester reactive oxygen species and reduce tissue damage. This study investigates the role of MT in H. pylori-induced gastritis in mice.

MATERIALS AND METHODS

Control (MT+/+) and MT-null (MT-/-) mice were inoculated with either 1 x 108H. pylori or H. felis, and were infected for 4, 8 and 16 weeks or 8 weeks, respectively. H. pylori load was determined by culture. Myloperoxidase activity and MT levels were also determined.

RESULTS

The stomachs of H. felis-infected mice were more severely inflamed than those of H. pylori-infected mice. H. felis-induced gastritis was more severe (p =.003) in MT-/- than in MT+/+ mice. MT-/- mice also had higher (60%; p <.05) H. pylori loads than MT+/+ mice 4 weeks after infection but not 8 or 16 weeks after infection. Myloperoxidase activity with H. pylori was similar between MT+/+ and MT-/- mice. Thirty-three per cent greater (p <.05) myloperoxidase activity was observed in MT-/- than in MT+/+ mice infected with H. felis. In MT+/+ mice infected with H. pylori, liver MT was increased by 33 and 39% (p <.05) at 8 and 16 weeks, respectively, whereas gastric MT increased by 46% (p <.05) at 4 weeks and declined to baseline levels at 8 and 16 weeks.

CONCLUSIONS

Mice lacking MT are more susceptible to H. pylori colonization and gastric inflammation, indicating that MT may be protective against H. pylori-induced gastritis.

Delta (13)C-urea breath test value is a useful indicator for Helicobacter pylori eradication in patients with functional dyspepsia

BACKGROUND

Eradication of Helicobacter pylori is not routinely recommended for the symptomatic relief and the prevention of gastric cancer in patients with functional dyspepsia. The present study investigated a useful indicator of H. pylori eradication in such patients by determining the optimal cutoff value of a 13C-urea breath test (UBT).

METHODS

One hundred dyspeptic patients participated in the study. Dyspepsia was scored, and a 13C-UBT administered. A level of delta 13C-UBT of>4 per thousand was diagnosed as H. pylori-positive. After the stomach was endoscopically sprayed with phenol red, biopsy specimens were taken from the antrum, body and cardia of the stomach for the assessment of H. pylori density, and activity (neutrophil infiltration) and degree (lymphocyte infiltration) of gastritis.

RESULTS

Correlation between delta 13C-UBT and dyspepsia score was not found. Delta 13C-UBT significantly correlated with H. pylori density score in the total stomach (r = 0.53, P < 0.0001), neutrophil (r = 0.34, P = 0.0005) and lymphocyte score (r = 0.69, P < 0.0001). Twenty-six of the 100 subjects had a neutrophil score of >or=4, lymphocyte score of >or=4, and H. pylori score of >or=4. Their 95% confidence interval of mean was 58.2 per thousand, which reflects moderate to marked acute and chronic gastritis, and dense H. pylori colonization.

CONCLUSIONS

The 13C-UBT is a reliable semiquantitative test to assess H. pylori density and the activity and degree of gastritis. It is proposed that H. pylori eradication therapy might be beneficial for patients with functional dyspepsia with a delta 13C-UBT of >58.2 per thousand.

[Genetics and environmental factors in gastric carcinogenesis]

BACKGROUND

Gastric cancer is considered to be the second most common cancer worldwide. Carcinogenesis of the stomach is a multi-stage process. The progression from normal epithelial to tumor cells may involve at least five stages: superficial gastritis, chronic atrophic gastritis, intestinal metaplasia, dysplasia and carcinoma. These sequential changes in the gastric mucosa may occur over a period of many years as a result of exposure to a variety of exogenous and/or endogenous factors which cause genetic alterations. Recent developments in molecular genetics have shown that the accumulation of these multiple genetic alterations, including activation of oncogenes and inactivation of tumor-suppressor genes, results in cancer development. Genetic alterations previously reported in gastric carcinomas include amplifications or mutations of the c-ERBB2, K-RAS, c-MET and TP53. Chromosomal gains were also found in various combinations with chromosomal losses and may be associated with the overexpression of dominant oncogenes contributing to tumor progression.

CONCLUSIONS

These accumulated genetic changes in carcinomas provide evidences for the stepwise mode of gastric carcinogenesis through the accumulation of a series of genetic alterations.

Effect of interlukin-1beta on proliferation of gastric epithelial cells in culture

BACKGROUND

Helicobacter pylori is the main risk factor for the development of non-cardia gastric cancer. Increased proliferation of the gastric mucosa is a feature of H. pylori infection. Mucosal interkeukin-1beta production is increased in H. pylori infection and IL-1beta genotypes associated with increased pro-inflammatory activity are risk factors for the development of gastric cancer. The effect of IL-1beta on gastric epithelial cell proliferation has been examined in this study.

METHODS

AGS cells were cultured with IL-1beta. DNA synthesis was assed by [3H]thymidine incorporation and total viable cell numbers by MTT assay.

RESULTS

IL-1beta dose dependently increased DNA synthesis and cell numbers. The enhanced proliferation was blocked by interleukin-1 receptor antagonist. Addition of neutralising antibody to GM-CSF reduced IL-1beta-stimulated proliferation by 31 +/- 4 %. GM-CSF alone significantly stimulated proliferation. Addition or neutralisation of IL-8 had no effect on basal or IL-1beta-stimulated proliferation. The tyrosine kinase inhibitor genistein completely blocked IL-1beta-stimulated proliferation and inhibition of the extracellular signal related kinase pathway with PD 98059 inhibited IL-1beta stimulated proliferation by 58 +/- 5 %.

CONCLUSIONS

IL-1beta stimulates proliferation in gastric epithelial cells. Autocrine stimulation by GM-CSF contributes to this proliferative response. Signalling via tyrosine kinase activity is essential to the mitogenic response to IL-1beta. The extracellular signal related kinase pathway is involved in, but not essential to downstream signalling. IL-1beta may contribute to the hyperproliferation seen in H. pylori- infected gastric mucosa, and be involved in the carcinogenic process.

An update on Helicobacter pylori microbiology and infection for the new millennium

The finding of the bacterium Helicobacter pylori in patients with symptomatic gastric diseases was a breakthrough for both treatment of peptic ulcer disease and studies of other infectious diseases. Helicobacter pylori infection is rare among the young, indicating that improved childhood living conditions have halted the transmission of the bacterium within families, with a parallel decrease in symptomatic gastroduodenal diseases. Extensive strain variation in H. pylori has been demonstrated at both the genomic and the protein level, and the interstrain variation is higher than in any other bacterium studied so far. Pathogenic markers in H. pylori and host genetics are both of importance for disease outcome. Genotypic or phenotypic markers of H. pylori strains may be used to discriminate patients who should undergo eradication therapy from those who might not benefit from it. Possible positive effects of the infection are still under investigation, and several hypotheses regarding the etiology of diseases in different parts of the stomach have been proposed. To be able to separate the disease-causing infections from the silent infections is a real challenge for the new millennium, and one of the most important issues for therapy and prevention, in the research field of H. pylori.

The role of Helicobacter pylori in paediatrics

Helicobacter pylori is a bacterium that colonizes the human stomach, especially during childhood. Although it has been studied intensively during the past decade, many controversies still exist on many important issues, including the clinical relevance of virulence factors, indications for treatment, recommended procedures for diagnosis and the typical symptom profile, among others. The lack of double-blind, placebo-controlled studies in children illustrates the paucity of hard scientific data, and is the major reason for differences in opinion. Therefore, the present review of literature published during the past 2 years raises many questions.

Gastric mucosal inflammation and epithelial cell turnover are associated with gastric cancer in patients with Helicobacter pylori infection

BACKGROUND

Infection with a virulent Helicobacter pylori strain is associated with gastric mucosal damage and the increased risk of gastric cancer.

AIMS

To examine the characteristics of host gastric mucosal responses in patients with gastric cancer, histological grade of gastritis, gastric epithelial apoptosis, and proliferation were studied.

METHODS

Thirty two patients with early gastric cancer and 32 sex and age matched controls were studied. All subjects were infected with a virulent H pylori strain (vacA s1/m1, cagA positive genotype). Biopsy specimens were taken from the antrum and the corpus of the stomach. The grade of gastritis was assessed according to the updated Sydney system. Apoptotic cells were detected using terminal uridine deoxynucleotidyl nick end labelling, and epithelial cell proliferation was determined by means of the Ki-67 labelling index.

RESULTS

In patients with gastric cancer, significantly higher grades were observed when glandular atrophy (p < 0.05) and intestinal metaplasia (p < 0.01) were present in the antrum, and when mononuclear cell infiltration was present in the corpus (p < 0.05). The numbers of apoptotic cells were increased in patients with cancer (p < 0.05) and the apoptotic index correlated significantly with the grade of glandular atrophy. Epithelial cell proliferation was more likely to be increased in mucosa where intestinal metaplasia was present.

CONCLUSIONS

Infection with H pylori causes increased gastric epithelial apoptosis, resulting in more severe glandular atrophy in patients with gastric cancer. Increased damage of gastric epithelial DNA and the presence of more severe atrophic gastritis might contribute to the development of gastric cancer.