Increased gastric epithelial cell proliferation in Helicobacter pylori associated follicular gastritis.

AIMS: An increase in the proliferative state of the gastric epithelium has been attributed to infection with Helicobacter pylori. In order to obtain a more precise estimate of the magnitude of this change, the proliferative state of 17 cases of florid H pylori associated follicular gastritis was examined using the antibody MIB-1. METHODS: Comparable results were produced from control and gastritis cases by using a combination of two reproducible measures of the labelled cells. Dividing cells in the gastric mucosa are concentrated within a proliferating compartment, situated at the base of the crypts. This compartment was measured and expressed as a proportion of the total crypt length. The proportion of positively labelled cells within the compartment was also counted. RESULTS: The proliferation compartment in the gastritis cases occupied 45.6% of the gastric crypt compared with 15.4% in the control group. Of the cells in the proliferating compartment, 79.5% were positively labelled in the gastritis cases and 33.4% in the control group. CONCLUSIONS: The convoluted nature of the gastric crypt does not make it a forgiving experimental model. The use of long lengths of mucosa obtained from gastrectomy specimens permitted the production of consistent results, using a morphometric method. The greater than 100% difference in the proportion of proliferating cells between the two groups suggests that further investigation is warranted.     

Helicobacter pylori gastritis and primary gastric non-Hodgkin's lymphomas.

AIMS--To evaluate further the relation between gastric malignant lymphoma of the mucosa associated lymphoid tissue (MALT) and Helicobacter pylori. METHODS--One hundred and sixty two surgical specimens of MALT lymphoma were retrospectively investigated to determine tumour type and inflammatory patterns. In 121 cases biopsy specimens obtained before surgery were available and stained with haematoxylin and eosin, periodic acid Schiff, Giemsa and Warthin-Starry stains. RESULTS--Residual lymphoid follicles were found less often in high grade malignant than in low grade malignant MALT lymphomas. Chronic active gastritis was shown within the mucosa at some distance from the tumours in 143 of 146 specimens. In all the cases for which biopsy specimens could be evaluated, colonisation of the mucosa by H pylori had occurred. Lymphoid follicles and lymphoid aggregates were detected in 82.7% of the antral, and in 85% of the body mucosa specimens. CONCLUSIONS--These data support the hypothesis that H pylori has an important role in the development of MALT lymphomas. Furthermore, the chronic inflammation preceding malignant transformation might enhance the probability of malignant transformation via chronic stimulation of the lymphoid tissue. This might in part indicate why MALT lymphomas occur most often in the stomach.     

Helicobacter pylori-induced chronic active gastritis, intestinal metaplasia, and gastric ulcer in Mongolian gerbils

The establishment of persisting Helicobacter pylori infection in laboratory animals has been difficult, but in 1996 Hirayama reported the development of a successful Mongolian gerbil model. The present study was undertaken with two aims: to better characterize the normal histological structure and histochemical properties of the gastric mucosa of the Mongolian gerbil; and to evaluate the progression of the histopathological features of H. pylori-induced gastritis in this animal model for one year after the experimental infection. Seventy-five Mongolian gerbils were used. Mongolian gerbils were sacrificed at 2, 4, 8, 12, 26, 38, and 52 weeks after H. pylori inoculation. Sections prepared from stomachs immediately fixed in Carnoy's solution were stained with hematoxylin and eosin and Alcian blue at pH 2.5/periodic acid-Schiff, a dual staining consisting of the galactose oxidase-cold thionin Schiff reaction and paradoxical Concanavalin A staining, and with immunostaining for H. pylori and BrdU. H. pylori infection induced in the Mongolian gerbil a chronic active gastritis, in which a marked mucosal infiltration of neutrophils on a background of chronic inflammation became detectable 4 weeks after inoculation and continued up to 52 weeks. Intestinal metaplasia and gastric ulcers appeared after 26 weeks in some of the animals, whereas others developed multiple hyperplastic polyps. The Mongolian gerbil represents a novel and useful model for the study of H. pylori-induced chronic active gastritis and may lend itself to the investigation of the epithelial alterations that lead to intestinal metaplasia and gastric neoplasia.     

Helicobacter pylori infection and chronic gastritis in gastric cancer.

AIMS: To investigate the prevalence of Helicobacter pylori associated chronic gastritis in patients with gastric cancer. METHODS: Serum IgG antibodies for H pylori were determined in 54 consecutive patients with gastric carcinoma. The prevalence of H pylori in gastric mucosa was also examined histologically (modified Giemsa) in 32 patients from whom adequate biopsy specimens of the antrum and corpus were available. Thirty five patients with gastrointestinal tumours outside the stomach and 48 with non-gastrointestinal malignancies served as controls. RESULTS: Of the 54 patients, 38 (70%) had H pylori antibodies (IgG) in their serum (three additional patients had H pylori antibodies IgA, class specific but not IgG specific). This prevalence was significantly higher (p less than 0.05) than that (49%) in the 35 controls. No differences in prevalence of H pylori antibodies were found between gastric cancer cases of intestinal (IGCA) or diffuse (DGCA) type, both these types showing H pylori antibodies (IgG) in 71% of the patients. In the subgroup of 32 subjects, five patients had normal gastric mucosa and four showed corpus limited atrophy ("pernicious anaemia type" atrophy of type A). All of these nine patients had no evidence of current or previous H pylori infection in serum (no IgG antibodies) or in tissue sections (negative Giemsa staining). The remaining 23 patients had antral or pangastritis, and all had evidence of current or previous H pylori infection. CONCLUSIONS: H pylori associated chronic gastritis was the associated disease in 75% of the patients with gastric cancer occurring equally often in both IGCA and DGCA groups. About 25% of cases seem to have a normal stomach or severe corpus limited atrophy, neither of which showed evidence of concomitant H pylori infection.     

The comparison of histologic gastritis in patients with duodenal ulcer, chronic gastritis, gastric ulcer and gastric cancer

This study was designed to investigate the differences of histologic gastritis according to the endoscopic diagnosis, and between H. pylori positive and negative gastritis, using the Sydney system. A total of 122 patients (42 duodenal ulcer, 31 chronic gastritis, 35 gastric ulcer and 14 gastric cancer) underwent endoscopy with biopsies from the antrum and body. Among the 122 patients, 104 (85%) were H. pylori positive. H. pylori density of the antrum was significantly higher in duodenal ulcer than in chronic gastritis, gastric ulcer, and gastric cancer. The positivity of intestinal metaplasia was lowest in duodenal ulcer and highest in gastric cancer. H. pylori density as well as grade of activity, inflammation and atrophy were significantly higher in the antrum than in the body in duodenal ulcer, while in chronic gastritis, gastric ulcer and gastric cancer there was no difference of H. pylori density, activity, inflammation and atrophy between the antrum and body. The grade of activity and chronic inflammation were significantly higher in H. pylori positive patients than in H. pylori negative patients in both the antrum and body. In conclusion, the gastritis of duodenal ulcer was mainly localized to the antrum, while the gastritis of chronic gastritis, gastric ulcer or gastric cancer was rather uniform in the antrum and body. H. pylori seemed to be related to the development of chronic inflammation and activity.     

Association of Helicobacter pylori with gastritis and peptic ulcer diseases

The occurrence of Helicobacter pylori(H.pylori) and its relationship with gastric mucosa were studied by light and electron microscopy and culture of biopsy specimens from gastric mucosa of 160 patients with upper gastrointestinal symptoms. H. pylori were present in 96.6% of patients with active chronic gastritis, 100% of patients with duodenal ulcer and 76.9% of patients with gastric ulcer, while present in only 6.3% of individuals with histologically normal gastric mucosa. The bacteria colonized the antral mucosa more frequently than the body or than the duodenal cap mucosa. The bacteria were rarely seen in the intestinalized epithelium per se, but there was no significant difference in prevalence of H. pylori between gastritis with intestinal metaplasia and gastritis without intestinal metaplasia. H. pylori could be seen in close association with the surface of gastric epithelial cells below the mucus layer without evidence of intracellular parasitism, All of the strains tested were susceptible to penicillin, erythromycin, and most of them susceptible to tinidazole and bismuth salts. It is concluded that H. pylori are highly associated with gastritis and peptic ulcer diseases and its prevalence rates in patients with those diseases is higher than in developed countries. This strong association of H. pylori infection with gastritis and peptic ulcer diseases suggest a possible etiologic role for the bacterium in those diseases.     

Light and electron microscopic immunohistochemical investigation on G and D cells in antral mucosa in Helicobacter pylori-related gastritis.

Recently, it has been recognized that Helicobacter pylori (H. pylori) infection is associated with an exaggeration of basal and meal gastrin secretion. We investigate whether there is a relationship between H. pylori-related chronic gastritis and G-cell and D-cell number and granule density index of G and D cells. - The number of antral G cells and D cells and granule density index of D and G cells are compared between thirty two patients with H. pylori-related chronic gastritis and twelve patients without H. pylori and inflammation. Antral mucosal biopsy specimens are examined using light and electron immunohistochemical techniques. - The number of G cells is the same in either infected or uninfected patients (98.40 +/- 11.39, 109.25 +/- 12.76 vs 101.17 +/- 7.72 for infected patients with non atrophic and with mild atrophic chronic gastritis and uninfected controls, respectively) except for the cases with moderate gastric mucosal atrophy, where G cells (58.22 +/- 5.63) decrease in number. The number of D cells is decreased in all patients with H. pylori-related gastritis. G cell granule density index is significantly (p < 0.05) increased in patients with H. pylori-related chronic gastritis than in controls (3.15 +/- 0.43 vs 2.528 +/- 0.01). D cell granule density index is similar between patients with H. pylori chronic gastritis and controls (3.18 +/- 0.05 vs 3.166 +/- 0.12). It is concluded that decreased D cells number in patients with H. pylori-related chronic gastritis might be one of the reasons for the existing hypergastrinaemia.     

Helicobacter pylori-related and -non-related gastric cancers do not differ with respect to chromosomal aberrations

Gastric carcinogenesis is strongly associated with Helicobacter pylori infection, but the underlying genetic mechanisms are largely unknown. The aim of this study was to correlate chromosomal aberrations in gastric cancer to H. pylori status and its different strains, as well as to histological type and other clinico-pathological variables. DNA from 46 gastric cancers (male/female 35/11, age 27-85 years) was extracted from formaldehyde-fixed, paraffin-embedded material and tested for chromosomal gains and losses by comparative genomic hybridization (CGH). Chromosomal aberrations with frequencies of 20% or higher were considered to be non-random changes associated with gastric cancer. The mean number of chromosomal events per tumour was 9.7 (range 0-27), with a mean of 3.2 gains (range 0-16) and 6.5 losses (range 0-15). Gains were most frequently found at chromosomes 8q and 13q (24% and 26%, respectively). Losses were predominantly found on chromosome arms 2q, 9p, 12q, 14q, 15q, 16p, 16q, 17p, 17q, 19p, 19q, and 22q (22%, 30%, 43%, 22%, 33%, 50%, 28%, 50%, 39%, 33%, 39%, and 37%, respectively). Common regions of overlap narrowed down to 2q11-14, 8q23, 9p21, 12q24, 13q21-22, 14q24 and 15q11-15. The mean number of gains was higher in tumours with metastases than in localized tumours (4.1 vs. 1.9, p=0.04). Tumours with a loss at 17p showed a higher number of losses than tumours without a 17p loss (9. 5 vs. 4.7 on average, p<0.001). Neither H. pylori status (+, n=25; -, n=21) nor H. pylori strain was correlated to the total number of events or to any specific chromosomal aberration, nor were there differences between intestinal (n=30) and diffuse (n=15) cancers or any other clinico-pathological variable tested. In conclusion, a complex of chromosomal aberrations is involved in gastric cancer, but their pattern does not depend on H. pylori status or strain, nor on the histological type of the tumour. The exact biological meaning of these aberrations in carcinogenesis needs further clarification.     

Helicobacter pylori in patho- and morphogenesis of chronic gastritis and peptic ulcer

Review of the literature on the role of Helicobacter pylori (HP) in the patho- and morphogenesis of chronic gastritis (CG) type B, gastric ulcer (GU) and duodenal ulcer (DU) is presented. Various hypotheses of pathogenetic effect of HP, histologic and ultrastructural characteristics of changes in the gastric and duodenal mucosa in HP infection are presented. The majority of authors consider HP as a possible pathogenic factor in CG type B, GU and DU. However, there are works in which HP is regarded as a saprophyte or a secondary infection. This indicates a necessity of further studies.     

Antibody response of patients with Helicobacter pylori-related gastric adenocarcinoma: significance of anti-cagA antibodies

The aim of this study was to search for a specific antibody pattern in sera from patients suffering from Helicobacter pylori-related gastric adenocarcinoma (GAC). The serological response of 22 patients suffering from GAC, 31 patients with gastroduodenal ulcer, and 39 asymptomatic subjects was analyzed using immunoblotting performed with three H. pylori strains: strain ATCC 43579; strain B110, isolated from a patient with ulcers; and strain B225, isolated from a patient with GAC. In addition, the latex agglutination test Pyloriset Dry was used to analyze ambiguous sera. H. pylori seropositivity was 75% in the GAC group, 61.3% in the ulcer group, and 56.4% in the asymptomatic group. Anti-CagA antibodies were found more often in the GAC group (48.8%) and in the ulcer group (47.3%) than in the asymptomatic group (21.2%). These percentages depended on the strain used as an antigen: in the GAC group, the anti-CagA frequencies were 93.3, 40, and 13.3% with strains B225, B110, and ATCC 43579, respectively. Thus the presence of anti-CagA antibodies was increased in patients suffering from H. pylori-related GAC, in particular when the CagA antigen was from a GAC strain. These data suggest the existence of a CagA protein specifically expressed by H. pylori strains isolated from GAC patients.     

Modes of Helicobacter colonization and gastric epithelial damage

A total of 144 gastric biopsies colonized by Helicobacter-like organisms were studied under light and differential interference contrast microscopy for the modes of bacterial colonization. Biopsies were also graded for the degree of epithelial damage (epithelial-damage-grade: 0 to 6, in ascending order of severity) and density of Helicobacter-like organism (Helicobacter-grade: 0 to 6, in ascending order of bacterial density). Three modes of colonization were identified: free-in-mucus, surface-adhesion and intercellular colonization. Because light microscopy cannot definitely prove the presence of intracellular colonization, bacteria located between cells and below the apical cell border were counted together as intercellular colonization. Bacteria free-in-mucus were seen in all biopsies. Surface adhesion was seen in 50-87.9% of biopsies, without obvious correlation with the epithelial-damage- and Helicobacter-grades. The incidences of intercellular and intracellular colonization were directly proportional to the epithelial-damage- and Helicobacter-grades. Free-in-mucus as the predominant mode of colonization was mainly seen in biopsies with lower (1-3) epithelial-damage- and Helicobacter-grades. Conversely, biopsies with intercellular colonization as the predominant mode of colonization were mainly cases with higher (4-6) epithelial-damage- and Helicobacter-grades. In cases showing predominantly bacteria between cells, 69.2% had a gastric ulcer whereas only 38.8% of cases showing predominantly bacteria free-in-mucus showed ulceration (P < 0.01). These results indicate that Helicobacter-like organisms can invade and penetrate between epithelial cells. When free-in-mucus, Helicobacter-like organisms are less likely to induce epithelial damage. However, the more invasive modes of colonization (intercellular) were associated with severe epithelial damage and high Helicobacter density.(ABSTRACT TRUNCATED AT 250 WORDS)     

Up-regulation of cathepsin X in Helicobacter pylori gastritis and gastric cancer

Recently, we identified increased cathepsin X expression in H. pylori-infected gastric mucosa. Here, we describe further up-regulation in gastric cancer and report on the role of inflammatory cytokines required for cathepsin X up-regulation in H. pylori-infected gastric mucosa, as well as on consequences for cellular invasion. Biopsy specimens were taken from the antrum, corpus and cardia of H. pylori-infected and non-infected patients. Gastric cancer samples were obtained from patients undergoing gastric surgery. Cathepsin X was detected in gastric mucosa by quantitative real-time RT-PCR, western blotting and immunohistochemistry. Induction of cathepsin X expression in epithelial and inflammatory cells caused by H. pylori infection was tested in in vitro contact and non-contact co-cultures of AGS cells and monocytic cells. Patients with H. pylori gastritis showed significantly higher cathepsin X mRNA (2.5-fold) and protein (1.6-fold) expression than H. pylori-negative patients. Cathepsin X was also up-regulated in gastric cancer (3-12-fold) compared to non-neoplastic mucosa. Cathepsin X was predominantly expressed by macrophages in the mucosal stroma and in glands of the antral mucosa. In addition, tumour cells stained for cathepsin X in 26 (68%) patients with gastric carcinoma. In general, staining was significantly more common (20 vs. 6 patients) and more intense (3.55 vs. 0.83) in intestinal type gastric cancer than in the diffuse type. In vitro cell culture experiments revealed that intercellular signalling between pathogenicity island (PAI)-positive H. pylori-infected epithelial cells and macrophages via soluble factors in the culture medium seems to be responsible for increased expression of cathepsin X in monocytes. Using antisense oligonucleotides, cathepsin X up-regulation was directly associated with higher invasiveness in vitro. Although no correlation of cathepsin X expression and TNM stage was found, our study demonstrates that cathepsin X plays a role not only in the chronic inflammation of gastric mucosa but also in the tumourigenesis of gastric cancer.     

Spectrotypic analysis of antibodies to Helicobacter pylori in patients with antral gastritis and duodenal ulcer.

AIMS--To investigate the anti Helicobacter pylori (H pylori) spectrotype associated with (a) antral gastritis and duodenal ulcer; (b) the H pylori eradicating treatment. METHODS--Spectrotypic analysis was performed by isoelectric focusing and reverse blotting (IEFRB) in a cross sectional study on sera from 70 patients with antral gastritis and duodenal ulcer. In addition, a longitudinal study was performed on 40 of these patients (20 with antral gastritis and 20 with duodenal ulcer) who underwent eradicating treatment. RESULTS--The cross sectional study showed that the oligoclonal spectrotype was present in 74% of antral gastritis patients and in 85% of duodenal ulcer patients. In only a minority of subjects (23% with antral gastritis and 3% with duodenal ulcer) was a polyclonal spectrotype observed. The longitudinal study showed a reduction in the intensity of the spectrotypic bands in 5/10 antral gastritis patients with eradicated H pylori as opposed to only 2/10 patients without eradication. A reduction was also observed in 6/11 eradicated v 0/9 non-eradicated patients with duodenal ulcer. Collectively, a reduction in the spectrotype was observed in 11/21 patients (52%) who--independently of the disease--underwent H pylori eradication, as opposed to 2/19 of the non-responder patients (10.5%). The polyclonal spectrotype was found exclusively in four patients with antral gastritis, all belonging to the group without eradication of H pylori after eradicating treatment. CONCLUSIONS--The anti H pylori oligoclonal spectrotype is the most common pattern observed in patients with antral gastritis and duodenal ulcer. After H pylori eradicating treatment the spectrotype does not change qualitatively, but the polyclonal pattern seems to be predictive of a poor response to eradication.