Helicobacter colonization and histopathological profile of chronic gastritis in patients with or without dyspepsia, mucosal erosion and peptic ulcer: a morphological approach to the study of ulcerogenesis in man

Antimicrobial resistance pattern of Helicobacter pylori in patients evaluated for dyspeptic symptoms in North-Eastern India with focus on detection of clarithromycin resistance conferring point mutations A2143G and A2142G within bacterial 23S rRNA gene

PURPOSE

In India there is evidence of antimicrobial resistance in Helicobacter pylori, a definitive pathobiont whose only known niche is human gastric mucosa. This in turn can lead to failure of treatment, persistence or chronicity of infection. This hospital based, prospective, observational study investigates the presence of antimicrobial resistance in the organism with focus on detection of A2143G and A2142G major point mutations in domain V of H. pylori 23S rRNA gene as a molecular mechanism of conferring resistance.

METHODS

Endoscopic gastric biopsy samples from 52 patients presenting with dyspeptic symptoms from January 2016 to December 2016 were subjected to culture in a microaerophilic environment using Campylobacter agar with for 2-5 days. Isolates were identified using gram-staining, motility test and biochemical reactions. Modified Kirby-Bauer Disc diffusion method was used to determine antimicrobial susceptibility against Clarithromycin, Metronidazole, Amoxycillin, Levofloxacin, Tetracycline, Cotrimoxazole and Erythromycin. Additionally, detection of A2143G and A2142G point mutations conferring Clarithromycin resistance was carried out using real time PCR following extraction and quantification of bacterial DNA. Histopathological examination was carried out on all biopsy samples. Descriptive and inferential statistical analytical methods were used. Differences were considered significant for p < 0.05.

RESULTS

Culture positivity for H. pylori by phenotypic method was found to be 36.54%. Histopathologic Examination detected H. pylori in 55.7% and PCR detected 48.08% for either the wild type or one of two mutant strains A2143G and A2142G. No sample was found positive for both mutations. Metronidazole showed the highest resistance among antibiotics (78.9%) followed by Clarithromycin (47.3%).

CONCLUSION

Prevalence of antimicrobial resistance in H. pylori in North-Eastern India is substantially high with A2143G mutation being clinically most important in conferring Clarithromycin resistance. This resistance might be associated with low eradication rates despite initiation of therapy. ROC analysis of PCR proved it to be a good diagnostic tool.

Inflammatory map of the gastroduodenal mucosa in patients with upper gastrointestinal symptoms. The role of H. pylori infection

INTRODUCTION AND AIM

The gastric mucosa has been studied since the pre-Helicobacter pylori (H. pylori) era, but the complete descriptions of the stomach and duodenum have been anecdotal, and those of the distal duodenum, exceptional. Our aim was to evaluate the different epidemiologic characteristics and the gastroduodenal inflammatory status in patients with upper gastrointestinal symptoms.

MATERIALS AND METHODS

We studied 138 patients divided into: the non-ulcer group (functional dyspepsia [n = 77] and GERD [n = 27]) and the ulcer group (peptic ulcer [n = 13] and duodenal ulcer [n = 21]). Ten biopsy samples (2 from the corpus, 3 from the antrum, 3 from the proximal duodenum, and 2 from the distal duodenum) were taken in each patient for histologic and/or microbiologic study.

RESULTS

The prevalence of dyspepsia, functional dyspepsia, and H. pylori was 80.4%, 69.4%, and 82.6%, respectively. The frequency of superficial chronic gastritis in the corpus was significantly higher in the ulcer group vs. the non-ulcer group, whereas there was more chronic atrophic gastritis in the antrum in the ulcer group (P < 0.05). Duodenitis was significantly more frequent in the ulcer group vs. the non-ulcer group, in both the proximal and distal duodenum. Pangastroduodenitis was a significant finding in the ulcer group. In both groups, chronic gastritis (corpus and antrum) and duodenitis (proximal and distal) were significantly related to the presence of H. pylori. Proximal duodenitis is not an uncommon finding in functional dyspepsia (37.7%) and is twice as frequent as distal duodenitis (16.9%).

CONCLUSIONS

The ulcer group presented with a gastroduodenal inflammatory map different from that of the non-ulcer group and was characterized by a higher frequency of superficial chronic gastritis in the corpus, chronic atrophic gastritis in the antrum, and a very high frequency of proximal duodenitis.

Morphogen Signals Shaping the Gastric Glands in Health and Disease

The adult gastric mucosa is characterised by deep invaginations of the epithelium called glands. These tissue architectural elements are maintained with the contribution of morphogen signals. Morphogens are expressed in specific areas of the tissue, and their diffusion generates gradients in the microenvironment. Cells at different positions in the gland sense a specific combination of signals that instruct them to differentiate, proliferate, regenerate, or migrate. Differentiated cells perform specific functions involved in digestion, such as the production of protective mucus and the secretion of digestive enzymes or gastric acid. Biopsies from gastric precancerous conditions usually display tissue aberrations and change the shape of the glands. Alteration of the morphogen signalling microenvironment is likely to underlie those conditions. Furthermore, genes involved in morphogen signalling pathways are found to be frequently mutated in gastric cancer. We summarise the most recent findings regarding alterations of morphogen signalling during gastric carcinogenesis, and we highlight the new stem cell technologies that are improving our understanding of the regulation of human tissue shape.

Follow the Metaplasia: Characteristics and Oncogenic Implications of Metaplasia's Pattern of Spread Throughout the Stomach

The human stomach functions as both a digestive and innate immune organ. Its main product, acid, rapidly breaks down ingested products and equally serves as a highly effective microbial filter. The gastric epithelium has evolved mechanisms to appropriately handle the myriad of injurious substances, both exogenous and endogenous, to maintain the epithelial barrier and restore homeostasis. The most significant chronic insult that the stomach must face is Helicobacter pylori (Hp), a stomach-adapted bacterium that can colonize the stomach and induce chronic inflammatory and pre-neoplastic changes. The progression from chronic inflammation to dysplasia relies on the decades-long interplay between this oncobacterium and its gastric host. This review summarizes the functional and molecular regionalization of the stomach at homeostasis and details how chronic inflammation can lead to characteristic alterations in these developmental demarcations, both at the topographic and glandular levels. More importantly, this review illustrates our current understanding of the epithelial mechanisms that underlie the pre-malignant gastric landscape, how Hp adapts to and exploits these changes, and the clinical implications of identifying these changes in order to stratify patients at risk of developing gastric cancer, a leading cause of cancer-related deaths worldwide.

Endoscopy-based Kyoto classification score of gastritis related to pathological topography of neutrophil activity

BACKGROUND

Endoscopy-based Kyoto classification for gastritis and pathological topographic distribution of neutrophil infiltration are correlated with gastric cancer risk.

AIM

To investigate the association between Kyoto classification and the topographic distribution of neutrophil activity.

METHODS

Kyoto classification score, ranging from 0 to 8, consisted of atrophy, intestinal metaplasia, enlarged folds, nodularity, and diffuse redness. Neutrophil activity was scored according to the updated Sydney System using biopsy samples obtained from the greater curvature of the corpus and the antrum. The participants were divided into four categories, inactive stomach, antrum-predominant gastritis, pangastritis, and corpus-predominant gastritis, based on the topographic distribution of neutrophil activity. Effects of sex, age, body mass index, drinking habit, smoking habit, family history of gastric cancer, serum Helicobacter pylori (H. pylori) antibody, and Kyoto score on topography of neutrophil infiltration were analyzed.

RESULTS

A total of 327 patients (comprising 50.7% women, with an average age of 50.2 years) were enrolled in this study. H. pylori infection rate was 82.9% with a mean Kyoto score of 4.63. The Kyoto score was associated with the topographic distribution of neutrophil activity. Kyoto scores were significantly higher in the order of inactive stomach, antrum-predominant gastritis, pangastritis, and corpus-predominant gastritis (3.05, 4.57, 5.21, and 5.96, respectively). Each individual score of endoscopic findings (i.e., atrophy, intestinal metaplasia, enlarged folds, nodularity, and diffuse redness) was correlated with the topographic distribution of neutrophil activity. On multivariate analysis, the Kyoto score, age, and serum H. pylori antibody were independently associated with the topographic distribution of neutrophil activity.

CONCLUSION

The Kyoto classification score was associated with the topographic distribution of neutrophil activity.

Severe gastritis decreases success rate of Helicobacter pylori eradication

BACKGROUND

In several studies, different risk factors other than antibiotic resistance have been documented with Helicobacter pylori eradication failure. We aimed in this study to investigate the relationship of gastric density of H. pylori, the occurrence/degree of gastric atrophy, and intestinal metaplasia (IM) with success rate of H. pylori eradication.

METHODS

Two hundred consecutive treatment naive patients who received bismuth containing standart quadruple treatment due to H. pylori infection documented by histopathological examination of two antral or two corpal biopsies entered this retrospective study. The updated Sydney system was used to grade the activity of gastritis, density of H. pylori colonization, atrophy, and IM. Stages III and IV of operative link for gastritis assessment (OLGA) or the operative link on gastric intestinal metaplasia assessment (OLGIM) stages was considered as severe gastritis. H. pylori eradication was determined via stool H. pylori antigen test performed 4 weeks after the end of therapy.

RESULTS

The presence of gastric atrophy and IM was significantly higher in patients with eradication failure (p = 0.001 and 0.01, respectively). Severe gastritis (OLGA III-IV and OLGIM III-IV) rates were higher in eradication failure group. A multiple linear regression analysis showed that OLGA and OLGIM stages were to be independent risk factors for eradication failure (p = 0.03 and 0.01, respectively).

CONCLUSION

Our results suggested that histopathologically severe gastritis may cause H. pylori eradication failure. In addition, we found that H. pylori density was not a risk factor for treatment failure in patients who receive quadruple treatment.

Helicobacter pylori HP(2-20) induces eosinophil activation and accumulation in superficial gastric mucosa and stimulates VEGF-alpha and TGF-beta release by interacting with formyl-peptide receptors

Eosinophils participate in the immune response against Helicobacter pylori, but little is known about their role in the gastritis associated to the infection. We recently demonstrated that the Hp(2-20) peptide derived from H. pylori accelerates wound healing of gastric mucosa by interacting with N-formyl peptide receptors (FPRs) expressed on gastric epithelial cells. The aim of the present study was to investigate whether eosinophils play a role in the repair of gastric mucosa tissue during H. pylori infection. Immuno-histochemistry and transmission electron microscopy were used to detect eosinophils in gastric mucosal biopsies. Eosinophil re-distribution occurred in the gastric mucosa of H. pylori-infected patients: their density did not change in the deep mucosal layer, whereas it increased in the superficial lamina propria just below the foveolar epithelium; eosinophils entered the epithelium itself as well as the lumen of foveolae located close to the area harboring bacteria, which in turn were also engulfed by eosinophils. The H. pylori-derived peptide Hp(2-20) stimulated eosinophil migration through the engagement of FPR2 and FPR3, and also induced production of VEGF-A and TGF-beta, two key mediators of tissue remodelling. We also demonstrate that Hp(2-20) in vivo induced eosinophil infiltration in rat gastric mucosa after injury brought about by indomethacin. This study suggests that eosinophil infiltrate could modulate the capacity of gastric mucosa to maintain or recover its integrity thereby shedding light on the role of eosinophils in H. pylori infection.

What is the impact of Helicobacter pylori density on the success of eradication therapy: a clinico-histopathological study

BACKGROUND AND OBJECTIVE

To investigate the presence of any possible association between H. pylori density in the stomach and the efficacy of triple (lansoprazole 30 mg b.i.d., clarithromycin 500 mg b.i.d. and amoxicillin 1g b.i.d. for 14 days) and bismuth-containing quadruple (colloidal bismuth subcitrate 300 mg q.i.d., lansoprazole 30 mg b.i.d., tetracycline 500 mg q.i.d. and metronidazole 500 mg t.i.d. for 14 days) eradication therapies.

METHODS

Eighty-five cases with H. pylori infection (proved by rapid urease test and histology) were studied. In each case, the density of H. pylori colonization was graded according to the updated Sydney classification. H. pylori eradication was determined via the (14)C-Urea breath test performed 4 weeks after the end of therapy.

RESULTS

The eradication rate of H. pylori was 50% (30 out of 60) in the triple therapy and 92% (23 of 25) in the quadruple therapy group. In the triple therapy group, the eradication rate of H. pylori decreased as the initial density of H. pylori increased (density of H. pylori: 1, 58.3%; 2, 54.5%; 3, 52.4%; 4, 38.5%; 5, 33.3%). In two cases with eradication failure after quadruple therapy, the grades of bacterial density were 1 and 3.

CONCLUSION

H. pylori density, as assessed by histological grading, may predict the usefulness of triple therapy. The higher the H. pylori density, the less effective triple therapy will be at successful eradication of H. pylori. Quadruple therapy does not seem to be negatively affected by bacterial density.

An infection-enhanced oncolytic adenovirus secreting H. pylori neutrophil-activating protein with therapeutic effects on neuroendocrine tumors

Helicobacter pylori neutrophil-activating protein (HP-NAP) is a major virulence factor involved in H. pylori infection. HP-NAP can mediate antitumor effects by recruiting neutrophils and inducing Th1-type differentiation in the tumor microenvironment. It therefore holds strong potential as a therapeutic gene. Here, we armed a replication-selective, infection-enhanced adenovirus with secretory HP-NAP, Ad5PTDf35-[Δ24-sNAP], and evaluated its therapeutic efficacy against neuroendocrine tumors. We observed that it could specifically infect and eradicate a wide range of tumor cells lines from different origin in vitro. Insertion of secretory HP-NAP did not affect the stability or replicative capacity of the virus and infected tumor cells could efficiently secrete HP-NAP. Intratumoral administration of the virus in nude mice xenografted with neuroendocrine tumors improved median survival. Evidence of biological HP-NAP activity was observed 24 hours after treatment with neutrophil infiltration in tumors and an increase of proinflammatory cytokines such as tumor necrosis factor (TNF)-α and MIP2-α in the systemic circulation. Furthermore, evidence of Th1-type immune polarization was observed as a result of increase in IL-12/23 p40 cytokine concentrations 72 hours postvirus administration. Our observations suggest that HP-NAP can serve as a potent immunomodulator in promoting antitumor immune response in the tumor microenvironment and enhance the therapeutic effect of oncolytic adenovirus.

Predictive value of neutrophil infiltration as a marker of Helicobacter pylori infection

AIM: To evaluate the predictive value of neutrophil infiltration as a marker of Helicobacter pylori (H. pylori) infection.

METHODS: A total of 315 patients with dyspepsia symptoms who underwent upper gastrointestinal endoscopy were enrolled in this study. Biopsies were evaluated using the updated Sydney system. The medication history of all patients in the preceding 4 wk was recorded. The diagnosis of H. pylori infection was based on ¹³C-urea breath test at least 4 wk after withdrawal of antisecretory drugs, antibiotics and related drugs. For the patients with subtotal gastrectomy, the diagnosis of H. pylori infection was based on anti-H. pylori immunoglobulin G (IgG) antibody. Serum anti-H. pylori IgG antibody was measured by enzyme-linked immunosorbent assays (Biohit, Finland).

RESULTS: The sensitivity, specificity, positive predictive value and negative predictive value of neutrophil infiltration in the diagnosis of H. pylori infection were 92.3%, 83.5%, 77.4% and 94.7%, respectively. Neutrophil infiltration of gastric mucosa in the histological analysis was strongly associated with H. pylori infection (77.4% vs 5.3% in the neutrophil infiltration negative group, P = 0.000). Moderate neutrophil infiltration was more frequent in H. pylori infection when compared to mild infiltration (81.8% and 75%, respectively), but did not reach statistical significance. For those patients with negative rapid urease test, H. pylori was detected in 73.2% of patients with positive neutrophil infiltration on histology. In patients with subtotal gastrectomy, the diagnostic accuracy of neutrophil infiltration in H. pylori infection was 50%.

CONCLUSION: Neutrophil infiltration is closely associated with H. pylori and may be recognized as a sign of this infection.

A new crystal lattice structure of Helicobacter pylori neutrophil-activating protein (HP-NAP)

A new crystal lattice structure of Helicobacter pylori neutrophil-activating protein (HP-NAP) has been determined in two forms: the native state (Apo) at 2.20 Å resolution and an iron-loaded form (Fe-load) at 2.50 Å resolution. The highly solvated packing of the dodecameric shell is suitable for crystallographic study of the metal ion-uptake pathway. Like other bacterioferritins, HP-NAP forms a spherical dodecamer with 23 symmetry including two kinds of channels. Iron loading causes a series of conformational changes of amino-acid residues (Trp26, Asp52 and Glu56) at the ferroxidase centre.

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.

Adverse effects of long-term proton pump inhibitor therapy

Proton pump inhibitors have an excellent safety profile and have become one of the most commonly prescribed class of drugs in primary and specialty care. Long-term, sometimes lifetime, use is becoming increasingly common, often without appropriate indications. This paper is a detailed review of the current evidence on this important topic, focusing on the potential adverse effects of long-term proton pump inhibitor use that have generated the greatest concern: B12 deficiency; iron deficiency; hypomagnesemia; increased susceptibility to pneumonia, enteric infections, and fractures; hypergastrinemia and cancer; drug interactions; and birth defects. We explain the pathophysiological mechanisms that may underlie each of these relationships, review the existing evidence, and discuss implications for clinical management. The benefits of proton pump inhibitor use outweigh its risks in most patients. Elderly, malnourished, immune-compromised, chronically ill, and osteoporotic patients theoretically could be at increased risk from long-term therapy.

Adverse effects of proton pump inhibitors

Proton pump inhibitors (PPI) are very effective drugs used largely in acid related disorders. During the last years concern have been raised regarding their overutilisation in benign condition, such as gastroesophageal reflux disease. The debate focussed also on the risk of adverse events related to long term use of PPI. Apart of the case of Helicobacter Pylori (H. Pylori) positive patients, in whose long term acid suppression lead to the development of corpus predominant atrophic gastritis, precursor of cancer; the other assumed adverse events, have never been demonstrated in prospective studies. The attention should move towards the appropriate prescription of PPI, rather than the fear adverse effects of PPI. In fact, in clinical practise, PPI are often prescribed in patients without a specific acid related disease and continued long term based on their safety profile. This review focus on the main adverse events related to long term PPI use.

Evidence for transepithelial dendritic cells in human H. pylori active gastritis

BACKGROUND

Despite extensive experimental investigation stressing the importance of bacterial interaction with dendritic cells (DCs), evidence regarding direct interaction of Helicobacter pylori or its virulence products with DCs in the human gastric mucosa is lacking.

METHODS

Human gastric mucosa biopsies, with or without H. pylori infection and active inflammation, were investigated at light and electron microscopy level with immunocytochemical tests for bacterial products (VacA, urease, outer membrane proteins) and DC markers (DC-SIGN, CD11c, CD83) or with the DC-labeling ZnI(2)-OsO(4 )technique. Parallel tests with cultured DCs were carried out.

RESULTS

Cells reproducing ultrastructural and cytochemical patterns of DCs were detected in the lamina propria and epithelium of heavily infected and inflamed (but not of normal) mucosa, where DC luminal endings directly contact H. pylori and take up their virulence products. Cytotoxic changes (mitochondrial swelling, cytoplasmic vacuolation, autophagy) were observed in intraepithelial DCs and reproduced in cultured DCs incubated with H. pylori broth culture filtrates to obtain intracellular accumulation of VacA and urease. Granulocytes were also seen to contact and heavily phagocytose luminal H. pylori, while macrophages remained confined to basal epithelium, though taking up bacteria and bacterial products.

CONCLUSION

Human DCs can enter H. pylori-infected gastric epithelium, in association with other innate immunity cells, to take up bacteria and their virulence products. This process is likely to be important for bacterial sensing and pertinent immune response; however, it may also generate DC cytotoxic changes potentially hampering their function.

An open-labeled study of rebamipide treatment in chronic gastritis patients with dyspeptic symptoms refractory to proton pump inhibitors

To assess the efficacy of rebamipide therapy in chronic gastritis patients with refractory dyspeptic symptoms, we enrolled 30 patients with chronic gastritis nonresponsive to the antisecretory medications, proton pump inhibitors. Upper gastrointestinal endoscopy was performed in all patients to confirm and evaluate the severity of gastritis by gastric mucosal injury score and the histology by the updated Sydney system before and after treatment with rebamipide 300 mg daily for 8 weeks. At the end of the study, significant improvement in the scores for symptoms (epigastralgia, stomach heaviness, and abdominal fullness) and endoscopic mucosal injury were observed for all patients. The degrees of neutrophil activity in antrum and mononuclear cell inflammation in both body and antrum significantly decreased from baseline. Improvement of gastritis might be the mechanism by which rebamipide prevents gastric mucosal inflammation. In conclusion, rebamipide treatment improved symptom, endoscopic, and histologic features of chronic gastritis in patients with refractory dyspeptic symptoms.

Proton pump inhibitors, enterochromaffin-like cell growth and Helicobacter pylori gastritis

In both rodents and humans the development of gastrin-promoted gastric argyrophil enterochromaffin-like cell carcinoids requires the involvement of a genetic factor inherent to multiple endocrine neoplasia syndrome or of type A autoimmune chronic atrophic gastritis. Prolonged severe hypergastrinaemia acting on non-gastritic mucosa, as in Zollinger-Ellison syndrome patients, results in diffuse argyrophil enterochromaffin-like cell hyperplasia but, as a rule, does not produce tumours. Combination of chronic atrophic gastritis (mostly related to Helicobacter pylori infection) with hypergastrinaemia frequently causes linear and micronodular hyperplasia of argyrophil cells, whereas carcinoids are exceptional. No tumours or pre-neoplastic lesions have been observed in patients treated long-term with proton pump inhibitors, apart from rare cases in patients with combined Zollinger-Ellison and multiple endocrine neoplasia syndromes. A moderate increase in the incidence of argyrophil cell clustering, with or without hyperplasia, probably results from the parallel evolution of ulcer-associated Helicobacter gastritis into chronic atrophic gastritis. Eradication of H. pylori with a combination of proton pump inhibitors and antibiotics suppresses gastritis and prevents ulcer recurrence.

Intracellular, intercellular, and stromal invasion of gastric mucosa, preneoplastic lesions, and cancer by Helicobacter pylori

BACKGROUND AND AIMS

It is not clear how Helicobacter pylori, an apparently extracellular pathogen colonizing the luminal side of the gastric epithelium, invariably causes an immune-inflammatory response on the stromal side of the mucosa. Penetration of H pylori into epithelial cell lines and its interaction with immune-inflammatory cells have been documented in vitro. Several investigations also showed in vivo bacterial penetration into the epithelium up to the lamina propria; however, the identification as H pylori of the bacteria-like bodies observed in unchanged, metaplastic, or neoplastic mucosa remained sometimes questionable.

METHODS

To search for bacteria-like organisms, we used transmission electron microscopy on endoscopic biopsy specimens from 20 dyspeptic subjects and surgical specimens of neoplastic and nonneoplastic mucosa from 20 cancerous stomachs. To ascertain the H pylori nature of the organisms found, we used 6 different antibodies directed against bacterial lysates, purified vacuolating cytotoxin A, or purified cytotoxin-associated antigen A in immunogold tests. The results were compared with those of H pylori strains cultivated in vitro.

RESULTS

In nonmetaplastic gastric epithelium, cytochemically proven H pylori were detected, in the majority of cases, inside cytoplasm of epithelial cells, in intraepithelial intercellular spaces, and in underlying lamina propria, often in direct contact with immune-inflammatory cells and sometimes inside small blood vessels. Cytochemically proven H pylori were also observed inside 6 of 8 intestinal metaplasias and 9 of 20 cancers.

CONCLUSIONS

H pylori penetrates normal, metaplastic, and neoplastic gastric epithelium in vivo, intracellularly, or interstitially to cause a strong immune-inflammatory response and promote gastric carcinogenesis.

Elevated risk for gastric adenocarcinoma can be predicted from histomorphology

The number of patients with gastric cancer has more than doubled since 1985 in developing countries. Thus, the questions of whether it can be predicted from gastritis morphology, who is at risk and who has a lower risk of developing gastric carcinoma are raised. H pylori-infection leads to erosions, ulcerations, carcinoma, mucosa associated lymphoid tissue (MALT)-lymphoma and extragastric diseases only in some individuals. The frequency of ulcerations among H pylori-infected individuals is estimated to be 13%, gastric cancer about 1% and MALT lymphoma around 0.1%. In the literature a multistep model from chronic active H pylori-infection through multifocal atrophy, intestinal metaplasia, dysplasia (intraepithelial neoplasia) and carcinoma has been described. But this model cannot be applied to all routine cases. Since risk factors such as metaplasia and atrophy are paracancerous rather than precancerous conditions, this raises the question whether there is a better morphological marker. Differences in topography, grade and activity of Helicobacter gastritis in the antrum and corpus might be good markers for identifying those who are at risk of developing gastric cancer. It is known that the so-called corpus dominant

H pylori gastritis is found more frequently among individuals with early and advanced gastric cancer and within high risk populations. This is valid both for first-degree relatives of gastric cancer patients and for patients with gastric adenoma and hyperplastic polyps. In conclusion, corpus-dominant H pylori gastritis is significantly more common in patients with advanced and early gastric cancer, first-degree relatives of patients with gastric cancer, patients with gastric adenoma and gastric hyperplastic polyps. Therefore, all these patients are at risk of developing gastric cancer. Next, the question of who is at risk of developing corpus-dominant gastritis is raised. It appears that patients with a low acid output more frequently develop gastric cancer. Eradication therapy is never performed too early but probably sometimes too late after the patients pass a “point of no return”. Large prospective long term studies are necessary to prove this and identify new reliable markers for gastric cancer development.

[Association of Helicobacter pylori infection with nodular antritis and follicular gastritis]

INTRODUCTION

Helicobacter pylori (H. pylori) infection is known to be the must common cause of chronic gastritis having some endoscopic and pathologic characteristies as determinated by the Sydney System for Gastritis Classification. The aim of our case report was to point out the relationship between an endoscopic finding of nodular antritis and the presence of H. pylori infection and active chronic gastritis.

CASE REPORT

Our patient underwent upper gastrointestinal endoscopy for dyspeptic complaints and was diagnosed as having nodular antritis, but also underwent urease test and hystopathologic examination of antral mucosa, to determine the presence and density of H. pylori infection and the presence and severity of gastritis. After a course of anti H. pylori treatment, dyspepsia improved and new biopsy specimens obtained two months and six months afterwards revealed no pathological findings.

CONCLUSION

The case report supported the association of H. pylori infection of lymphoid follicles with nodular gastric mucosis.

Upregulation of cathepsin W-expressing T cells is specific for autoimmune atrophic gastritis compared to other types of chronic gastritis

AIM: To investigate a pathophysiological role of cathepsin W (CatW), a putative thiol-dependent cysteine protease, which is specifically expressed in cytotoxic lymphocytes, in different types of chronic inflammation of the gastric mucosa.

METHODS: Gastric and duodenal biopsies of patients with Helicobacter pylori (H pylori)-associated active gastritis (Hp, n = 19), chemically induced reactive gastritis (CG, n = 17), autoimmune atrophic gastritis (AIG, n = 20), lymphocytic corpus gastritis (LG, n = 29), celiac disease (CD, n = 10), and corresponding controls (n = 24) were analyzed by immunohistochemistry for the expression of CatW and CD45. Furthermore, immunohistochemical double staining with anti-CD3 and anti-cathepsin was performed for the samples of AIG.

RESULTS: Median values of CatW-expressing cells among CD45-positive immune cells were between 2% and 6% for normal gastric mucosa, CG, and LG, whereas the corresponding value was significantly increased for AIG (24.7%, P<0.001) and significantly decreased for HP (0.7%, P<0.05). Double staining with anti-CD3 and anti-CatW antibodies revealed that >90% of CatW-expressing cells in gastric mucosa of AIG were T cells. Duodenal mucosa had significantly more CatW/CD45-positive cells than normal gastric mucosa (median: 17.8% vs 2%, P<0.01). The corresponding proportion of CatW/CD45-positive cells was decreased in CD compared to duodenal mucosa (median: 2.1% vs 17.8%, P<0.05).

CONCLUSION: The opposite findings regarding the presence of CatW-positive cells in AIG (increase) and CD (decrease) reflects the different cellular composition of immune cells involved in the pathogenesis of these diseases.

Basophils Infiltrate Human Gastric Mucosa at Sites of Helicobacter pylori Infection, and Exhibit Chemotaxis in Response to H. pylori-derived Peptide Hp(2–20)

Basophils, which are normally confined to the circulation, can migrate to sites of allergic inflammation. Using the specific mAb, BB1, we detected basophil infiltration of the gastric mucosa of Helicobacter pylori-infected patients affected by moderate and severe gastritis. Basophils were not found in H. pylori-free individuals or in subjects with mild gastritis. The H. pylori-derived peptide, Hp(2-20), was a potent basophil chemoattractant in vitro, whereas the control peptide, Hp1, was ineffective. Basophils from peripheral blood of healthy volunteers expressed mRNA for the formyl peptide receptors, N-formyl-peptide receptor (FPR), FPR-like (FPRL)1, and FPRL2. Preincubation of basophils with FMLP or Hp(2-20) caused complete desensitization to a subsequent challenge with homologous stimulus. Incubation of basophils with a low concentration of FMLP, which binds with high affinity to FPR, but not to FPRL1 or FPRL2, did not affect the chemotactic response to Hp(2-20). In contrast, a high concentration of FMLP, which binds to FPRL1 and FPRL2, reduced the chemotactic response to Hp(2-20). The FPR antagonist, cyclosporin H, prevented chemotaxis induced by FMLP, but not by Hp(2-20). Hp(2-20) could be responsible, at least in part, for basophil infiltration of the gastric mucosa of H. pylori-infected patients presumably through the interaction with FPRL1 and FPRL2.

Recovery from gastric mucus depletion in the intact guinea pig mucosa

BACKGROUND

In developed countries one-third of the population is infected with the gastric pathogen Helicobacter pylori. In the early stages of H. pylori-induced gastritis, typical symptoms include gastric erosions and mucus depletions. Artificial mucus depletion was generated, demonstrating both consequent irritation and recovery processes in the mucosa.

METHODS

The mucus depletion was examined by removing a small cylinder of mucus from the surface of the explanted guinea pig corpus mucosa, leaving the epithelial surface intact. pH microelectrodes were inserted into the mucosa in vitro, measuring the epicellular mucus pH, the pH(i) of the underlying epithelial cells and the pH inside the gastric glands during mucus regeneration. Using infrared microscopy, the same process of mucus layer renewal was followed in anaesthetized animals.

RESULTS

The depletion exposed the tissue surface to low luminal pH levels. At a luminal pH of 2.5, a decrease was observed in the crypt outlet pH and surface cell pH(i), while deeper cells were less affected. However, a subsequent neutralization in the deep gland lumen was found. During the repair process, a quarter of the mucus layer was regenerated within the first 5 min. This newly secreted mucus formed a structure similar to that before depletion. Within 45 min, pH(i) and tissue-near pH values had fully recovered.

CONCLUSION

Following mucus depletion, there is a decrease in surface cell pH(i) and crypt outlet pH values. The repair process is then characterized by extensive mucus secretion and local cessation of acid secretion.

Effects of 6-12 months of esomeprazole treatment on the gastric mucosa

OBJECTIVE

The aim of this study was to determine the effect of 6-12 months of treatment with esomeprazole on the histopathology of the gastric mucosa.

METHODS

Two identically designed, randomized, placebo-controlled trials of esomeprazole 40, 20, or 10 mg daily for up to 6 months, as well as a noncomparative, multicenter trial of esomeprazole 40 mg daily for up to 12 months, were conducted in 1326 patients with healed erosive esophagitis (1294 negative for Helicobacter pylori [H. pylori]). Gastric biopsy samples were obtained before treatment and on completion of (or discontinuation from) the trials. Samples were evaluated for the presence of H. pylori, characteristics of acute gastritis or atrophic gastritis, and enterochromaffin-like cell pathology.

RESULTS

During treatment with esomeprazole, the number of patients with an improvement in gastric histological scores was typically greater than or equal to the number who worsened. Gastric histological scores worsened for each corporal or antral characteristic of gastritis in <6.2% of patients. Histological scores with esomeprazole and placebo were similar throughout the 6-month trials. Only one among 1326 patients treated with esomeprazole (H. pylori negative) had evidence of treatment-emergent atrophic gastritis. On final biopsy, 5-12% of patients had abnormal enterochromaffin-like cell scores (simple, linear, or micronodular hyperplasia). There were no instances of enterochromaffin-like cell dysplasia, carcinoids, or neoplasia.

CONCLUSIONS

Patients with healed erosive esophagitis receiving esomeprazole for up to 12 months had minor fluctuations in gastric histological scores, similar to those experienced in untreated populations. Use of esomeprazole did not raise any safety concerns with respect to the development of atrophic gastritis, or cause clinically significant changes in enterochromaffin-like cells.

Helicobacter pylori infection is not involved in the pathogenesis of either erosive or non-erosive gastro-oesophageal reflux disease

BACKGROUND

The majority of reflux patients have non-erosive reflux disease.

AIM

To evaluate the influence of Helicobacter pylori on oesophageal acid exposure in patients with both non-erosive and erosive reflux disease and in a group of controls. The pattern and distribution of chronic gastritis were also assessed.

METHODS

One hundred and twelve consecutive patients with symptoms of gastro-oesophageal reflux disease agreed to undergo both upper gastrointestinal endoscopy and 24-h oesophageal pH-metry. Patients were grouped as H. pylori-positive or H. pylori-negative on the basis of both CLO-test and histology, and as cases with or without oesophagitis on the basis of endoscopy. The controls consisted of 19 subjects without reflux symptoms and with normal endoscopy and oesophageal pH-metry.

RESULTS

H. pylori was positive in 35 patients (31%) and in six controls (31%); oesophagitis was found in 44 patients (39%) and non-erosive reflux disease in 68 (61%). The prevalence of chronic gastritis in the antrum and corpus was higher in H. pylori-positive than in H. pylori-negative patients (P < 0.001), but was more frequently mild (P < 0.001) than moderate or severe. The percentage total time the oesophageal pH < 4.0 was higher in patients than in controls (P < 0.008-0.001), but there was no difference between H. pylori-positive and H. pylori-negative patients (12.3% vs. 12%, P = 0.43) or H. pylori-positive and H. pylori-negative controls (1.07% vs. 1.47%, P = 0.19).

CONCLUSIONS

H. pylori infection had the same prevalence in reflux patients and in controls. It did not affect oesophageal acid exposure, as there was no difference between H. pylori-positive and H. pylori-negative individuals. The high prevalence of mild body gastritis in H. pylori-positive patients suggests that H. pylori eradication is unlikely to lead to gastric functional recovery, which might precipitate or worsen symptoms and lesions in patients with gastro-oesophageal reflux disease.

Diagnostic yield of gastric biopsy specimens when screening for preneoplastic lesions

The Sydney system recommends sites and numbers of stomach biopsies (mapping) for evaluation of Helicobacter pylori-associated lesions. The diagnostic yield of the recommended mapping technique in populations at high risk for gastric preneoplastic lesions has not been established. We evaluated pathology data from 733 endoscopies performed as part of an intervention study that assessed the effects of H. pylori treatment on preneoplastic conditions. Two pathologists assessed whether the mapping sequence of the 7 biopsy specimens obtained during each endoscopy was correctly followed and graded the specimens using the Sydney classification for gastritis. If the mapping sequence was followed, then we evaluated whether the amount of information obtained from 3 biopsy samples approximated that obtained from 5 and 7 biopsy samples. The mapping sequence was followed in only 239 (33%) endoscopies, indicating that experienced endoscopists can inadvertently misidentify sites in the stomach when obtaining specimens. When data from 7 specimens were used, H. pylori was found in 205 endoscopies, atrophy in 152, metaplasia in 135, and dysplasia in 22. When data from 3 specimens were used, the sensitivity was 99% for presence of H. pylori, 82% for atrophy and metaplasia, and 81% for dysplasia. When data from 5 specimens were used, the sensitivity was 100% for H. pylori, 96% for atrophy, and 95% for metaplasia and dysplasia. Although site-specific biopsy mapping is difficult in practice, the recommendations of the Sydney system as to the location and number of gastric biopsy specimens can adequately identify significant gastric histopathology.

Minor effects of Helicobacter pylori on gastric secretion and dose of lansoprazole during long-term treatment in ZE and non-ZE acid hypersecretors

BACKGROUND

Helicobacter pylori infection may increase or decrease acid secretion and may augment proton pump inhibitor efficacy. Pepsin effects have not been reported. In Zollinger-Ellison syndrome (ZE) specifically, H. pylori has been reported to decrease acid.

AIM

To examine H. pylori effects on secretion and dose of medication in hypersecretors (basal acid output > 15 mmol/h) undergoing long-term treatment with individually optimized lansoprazole doses.

METHODS

Sixty-five patients (47 ZE and 18 non-ZE), treated for > 3 months to 10 years, were tested every 6 months with endoscopy, gastric analysis and serum gastrin.

RESULTS

Forty-three per cent were H. pylori-positive. Acid, pepsin and gastrin were not different between H. pylori-positive and H. pylori-negative patients before or during long-term lansoprazole treatment. Initially, H. pylori-positive patients required less lansoprazole than H. pylori-negative patients (68 +/- 6 vs. 96 +/- 8 mg/day), but after 3 years the doses converged (83 vs. 86 mg/day). The disappearance of H. pylori in 15 patients caused no significant changes in acid, pepsin, gastrin or lansoprazole dose in the following 4 years.

CONCLUSIONS

H. pylori had no significant initial or long-term physiological or potential clinical effects on acid or pepsin secretion or gastrin in these acid hypersecretors.

Involvement of the corporal mucosa and related changes in gastric acid secretion characterize patients with iron deficiency anaemia associated with Helicobacter pylori infection

BACKGROUND

Recent studies have reported an association between iron deficiency anaemia and Helicobacter pylori. Helicobacter pylori could cause iron deficiency anaemia by altering iron absorption. We observed that most patients with Helicobacter pylori infection and iron deficiency anaemia present a chronic superficial pangastritis.

AIM

To investigate whether Helicobacter pylori-positive patients with iron deficiency anaemia have peculiar histological and functional features when compared with non-anaemic Helicobacter pylori-positive subjects.

PATIENTS

Fifty-one patients with iron deficiency anaemia, in whom chronic superficial Helicobacter pylori gastritis was the only gastrointestinal finding, and 103 non-anaemic Helicobacter pylori-positive controls were included in the study. Thirty-seven patients were randomly matched with 37 controls of the same sex and age.

METHODS

Gastroscopy, with antral (n=3) and body (n=3) biopsies, was performed. Gastrin and pepsinogen I levels and antiparietal cell antibodies were evaluated. Intragastric pH was also measured.

RESULTS

Gastritis involved the corporal mucosa in 90% of patients compared to 42.7% of controls (P < 0.0001). The mean inflammatory score in the gastric body was significantly higher among patients than in controls (2.2 vs. 0.6; P=0.012). Gastrin was significantly higher in patients than in controls (mean 60.2 vs. 29 pg/mL; P=0.0069). Intragastric pH was higher in patients than in controls (median 5.7 vs. 2; P=0.0026).

CONCLUSIONS

These data suggest that patients with iron deficiency anaemia and Helicobacter pylori infection have a peculiar pattern of gastritis with corporal involvement and related changes in intragastric pH.

Update on the pathologic approach to the diagnosis of gastritis, gastric atrophy, and Helicobacter pylori and its sequelae

Biopsy sampling of the gastric mucosa at diagnostic endoscopy provides information that cannot be obtained otherwise. The most common indication for gastric biopsy is the need to know whether the patient is infected with Helicobacter pylori or not and whether the stomach is gastritic or not. Microscopic examination of gastric biopsy specimens gives, in addition to H. pylori status, information about the grade, extent, and topography of gastritis- and atrophy-related alterations in the gastric mucosa. This information provides further possibilities for the assessment of risk and likelihood of various gastric disorders. The presence of atrophy (loss of mucosal glands) results in failures in secretory functions of the corresponding mucosa and leads to errors in the homeostasis of normal gastric physiology. The grade of atrophy of the corpus mucosa linearly correlates with peak and maximal output of acid. The presence of advanced (moderate or severe) corpus atrophy indicates an extremely hypochlorhydric or achlorhydric stomach in which, for example, ordinary peptic ulcer is unlikely or impossible in spite of a possible H. pylori infection. Some well characterized and common topographic phenotypes of H. pylori gastritis and atrophic gastritis can be delineated as follows: Predominance or restriction of the H. pylori-related inflammation in antrum, in association with a nonatrophic corpus mucosa--of which phenotype is the most common--and with an increased risk of peptic ulcer disease, duodenal ulcer in particular ("duodenal ulcer phenotype" of gastritis); the presence of atrophic gastritis in corpus of the stomach ("corpus predominant gastritis"), which indicates a low risk of peptic ulcer and a reduction in the capacity of the patient to secrete acid; the occurrence of advanced atrophic gastritis and intestinal metaplasia multifocally in the stomach (advanced "multifocal atrophic gastritis"), which are features of a gastritis type and which also indicate a low acid secretion capacity and an increased risk of gastric neoplasias ("gastric cancer phenotype of gastritis"), suggesting a need for a careful exclusion of concomitant presence of small focal neoplastic or dysplastic lesions; and the presence of normal and healthy gastric mucosa, which indicates an extremely low risk of both peptic ulcer disease or gastric cancer and, therefore, is a finding of high clinical relevance. The presence of duodenal or gastric ulcer in conjunction with normal, healthy gastric mucosa suggests either aspirin or nonsteroidal antiinflammatory drugs to be the most likely cause of the ulcer.

Helicobacter pylori effects on gastritis, gastrin and enterochromaffin-like cells in Zollinger-Ellison syndrome and non-Zollinger-Ellison syndrome acid hypersecretors treated long-term with lansoprazole

BACKGROUND

Helicobacter pylori is said to cause atrophy of the gastric corpus and enterochromaffin-like cell proliferation in gastro-oesophageal reflux disease (GERD) patients treated long-term with a proton pump inhibitor.

AIMS

To determine the effect of H. pylori infection on gastritis, enterochromaffin-like cell density and hyperplasia, mucosal atrophy and serum gastrin in patients with gastric hypersecretion (basal acid output gt; 15 mmol/h) with either hypergastrinemia (Zollinger-Ellison syndrome) or normal gastrin (non-Zollinger-Ellison syndrome) before and during long-term treatment with lansoprazole.

METHODS

Lansoprazole was individually titrated to reduce basal acid output to < 5 mmol/h (< 1 mmol/h in post-surgical Zollinger-Ellison syndrome). Gastric corpus biopsies were obtained every 6 months before treatment and up to 8 years later.

RESULTS

H. pylori was present in corpus biopsies in approximately 50%, causing active gastritis which resolved rapidly in 15 subjects after elimination of H. pylori. Patchy mild/moderate corpus atrophy was present at entry in two and at the end in four out of 60 patients, one being H. pylori-positive. Intestinal metaplasia (< 10%) was seen in six isolated biopsies (1% of total). H. pylori did not affect serum gastrin, enterochromaffin-like cell density or hyperplasia. Enterochromaffin-like cell density was twice as high in Zollinger-Ellison syndrome as in non-Zollinger-Ellison syndrome patients (241 vs. 126 cells/mm2, P < 0.001). Enterochromaffin-like cells remained normal in the non-Zollinger-Ellison syndrome hypersecretors regardless of H. pylori status.

CONCLUSION

Corpus enterochromaffin-like cell increases were related to serum gastrin elevation, but neither H. pylori nor long-term treatment with lansoprazole alone or together had any effect on enterochromaffin-like cell density or hyperplasia. Corpus acute gastritis resulted from H. pylori infection, but did not result in mucosal atrophy despite long-term proton pump inhibitor treatment and promptly resolved with loss of H. pylori.

Review article: potential gastrointestinal effects of long-term acid suppression with proton pump inhibitors

This review examines the evidence for the development of adverse effects due to prolonged gastric acid suppression with proton pump inhibitors. Potential areas of concern regarding long-term proton pump inhibitor use have included: carcinoid formation; development of gastric adenocarcinoma (especially in patients with Helicobacter pylori infection); bacterial overgrowth; enteric infections; and malabsorption of fat, minerals, and vitamins. Prolonged proton pump inhibitor use may lead to enterochromaffin-like cell hyperplasia, but has not been demonstrated to increase the risk of carcinoid formation. Long-term proton pump inhibitor treatment has not been documented to hasten the development or the progression of atrophic gastritis to intestinal metaplasia and gastric cancer, although long-term studies are required to allow definitive conclusions. At present, we do not recommend that patients be tested routinely for H. pylori infection when using proton pump inhibitors for prolonged periods. Gastric bacterial overgrowth does increase with acid suppression, but important clinical sequelae, such a higher rate of gastric adenocarcinoma, have not been seen. The risk of enteric infection may increase with acid suppression, although this does not seem to be a common clinical problem with prolonged proton pump inhibitor use. The absorption of fats and minerals does not appear to be significantly impaired with chronic acid suppression. However, vitamin B12 concentration may be decreased when gastric acid is markedly suppressed for prolonged periods (e.g. Zolllinger-Ellison syndrome), and vitamin B12 levels should probably be assessed in patients taking high-dose proton pump inhibitors for many years. Thus, current evidence suggests that prolonged gastric acid suppression with proton pump inhibitors rarely, if ever, produces adverse events. Nevertheless, continued follow-up of patients taking proton pump inhibitors for extended periods will provide greater experience regarding the potential gastrointestinal adverse effects of long-term acid suppression.

The neutrophil-activating protein (HP-NAP) of Helicobacter pylori is a protective antigen and a major virulence factor

Helicobacter pylori infection induces the appearance of inflammatory infiltrates, consisting mainly of neutrophils and monocytes, in the human gastric mucosa. A bacterial protein with neutrophil activating activity (HP-NAP) has been previously identified, but its role in infection and immune response is still largely unknown. Here, we show that vaccination of mice with HP-NAP induces protection against H. pylori challenge, and that the majority of infected patients produce antibodies specific for HP-NAP, suggesting an important role of this factor in immunity. We also show that HP-NAP is chemotactic for human leukocytes and that it activates their NADPH oxidase to produce reactive oxygen intermediates, as demonstrated by the translocation of its cytosolic subunits to the plasma membrane, and by the lack of activity on chronic granulomatous disease leukocytes. This stimulating effect is strongly potentiated by tumor necrosis factor alpha and interferon gamma and is mediated by a rapid increase of the cytosolic calcium concentration. The activation of leukocytes induced by HP-NAP is completely inhibited by pertussis toxin, wortmannin, and PP1. On the basis of these results, we conclude that HP-NAP is a virulence factor important for the H. pylori pathogenic effects at the site of infection and a candidate antigen for vaccine development.

Antral-type mucosa in the gastric incisura, body, and fundus (antralization): a link between Helicobacter pylori infection and intestinal metaplasia?

OBJECTIVES

Helicobacter pylori is a carcinogen; gastric carcinoma involves a multistep process from chronic gastritis to atrophy, intestinal metaplasia, and dysplasia. The aims of this study were to determine the types of mucosa at different gastric sites in H. pylori-infected and uninfected patients, and whether the presence of antral-type mucosa in the incisura, body, and fundus is associated with gastric atrophy and intestinal metaplasia.

METHODS

Two hundred and sixty-eight patients with dyspepsia were enrolled. Eight biopsies (i.e., antrum x3, body x2, fundus x2, and incisura x1) were obtained. One antral biopsy was used for the CLO-test. Three (each from the antrum, body, and fundus) were cultured. The remaining biopsies were examined histologically according to the updated Sydney System after staining with hematoxylin and eosin and Giemsa. A validated serological test was also applied.

RESULTS

Overall, 113 (42%) patients were infected with H. pylori. At the incisura, antral-type mucosa was more prevalent in infected than in uninfected patients (84% vs. 18%; odds ratio [OR] = 23.9, 95% confidence interval [CI] 12.5-45.8; p<0.001). Atrophic gastritis and intestinal metaplasia at the incisura was present in 19.5% and 13.3%, respectively, of infected, and 4.5% and 3.2%, respectively, of uninfected patients (both p<0.01). Moreover, atrophic gastritis at the incisura was associated with the presence of antral-type mucosa at the site (termed antralization); the prevalence of atrophic gastritis was 19.5% (24/123) in the presence of antralization, whereas the rate was 2.1% (3/145) without antralization (OR = 11.4, 95% CI 3.4-39.2; p<0.001). Similarly, at the incisura, 16.3% (20/123) of "antralized" cases and 1.4% (2/145) of "unantralized" cases had intestinal metaplasia (OR = 13.8, 95% CI, 3.2-60.7; p<0.001). The association between antralization at gastric body and fundus also appeared to be associated with atrophic gastritis and intestinal metaplasia at these sites.

CONCLUSIONS

Atrophic gastritis and intestinal metaplasia occurs predominantly at the gastric antrum and incisura with H. pylori infection. Antralization of the gastric incisura is a common event in H. pylori-infected patients, and appears to be associated with an increased risk of atrophic gastritis and intestinal metaplasia.

The Helicobacter pylori neutrophil-activating protein is an iron-binding protein with dodecameric structure

The neutrophil-activating protein (HP-NAP) of Helicobacter pylori is a major 17 kDa antigen of the immune response of infected individuals. Amino acid sequence comparison indicated a high similarity between HP-NAP and both bacterial DNA-protecting proteins (Dps) and ferritins. The structure prediction and spectroscopic analysis presented here indicate a close similarity between HP-NAP and Dps. Electron microscopy revealed that HP-NAP forms hexagonal rings of 9-10 nm diameter with a hollow central core as seen in Dps proteins, clearly different from the 12 nm icositetrameric (24 subunits) ferritins. However, HP-NAP is resistant to thermal and chemical denaturation similar to the ferritin family of proteins. In addition, HP-NAP binds up to 40 atoms of iron per monomer and does not bind DNA. We therefore conclude that HP-NAP is an unusual, small, ferritin that folds into a four-helix bundle that oligomerizes into dodecamers with a central hole capable of binding up to 500 iron atoms per oligomer.

Molecular and cellular activities of Helicobacter pylori pathogenic factors

Stomach infection with pathogenic strains of Helicobacter pylori causes in some patients severe gastroduodenal diseases. These bacteria produce various virulence factors and, here, we review the recent acquisition on the biochemical mode of action of three major factors. We discuss the role of urease both as buffer of the stomach pH and as source of ammonia. The vacuolating toxin alters the endocytic pathway of non-polarized cells, inducing the release of acid hydrolases, the depression of extracellular ligand degradation and of antigen processing and, in the presence of ammonia, swelling of late-prelysosomal compartments. In polarized epithelial monolayers, vacuolating toxin induces an increase of the paracellular permeability, independent of vacuolation. The neutrophil activating protein induces the production of oxygen radicals in human neutrophils and could contribute to the damage of the stomach mucosa. The activities of these factors are discussed in terms of the need of the bacterium of increasing the supply of nutrients from the stomach lumen and from the mucosa.

The gastric transitional zones: neglected links between gastroduodenal pathology and helicobacter ecology

The gastric transitional zones are the junctional zones between the different types of mucosa: antral-body, body-cardia, and antrum-duodenum. In this article, the importance of the transitional zone in determining disease outcome, specifically duodenal ulcer, gastric ulcer, and possibly gastric cancer, is reviewed. Both gastric ulcers and duodenal ulcers are located immediately adjacent to the transitional zones. The transitional zones are dynamic rather than static areas. Local acid levels determine the behavior of Helicobacter pylori at the antral-body transitional zone and, as a consequence, the geographic distribution of gastritis in the stomach and the formation of duodenal ulcer and gastric ulcer. This review also explains that diffuse antral gastritis and multifocal atrophic gastritis are part of the same disease and not separate entities.

Differing patterns of Helicobacter pylori gastritis in patients with duodenal, prepyloric, and gastric ulcer disease

BACKGROUND

We investigated the risk relationship between histotopographic patterns of Helicobacter pylori gastritis and peptic ulcer site.

METHODS

Three hundred and eighty-three infected patients were classified as having duodenal ulcer (n = 79), prepyloric ulcer (n = 39), gastric (angular) ulcer (n = 28), and no ulcer (n = 237). Antral and corpus biopsy specimens were taken. Sydney system-based scores for bacterial density and activity and degree of gastritis were added to antral and corpus sum scores (SS) (range, 0-9). These were used to categorize the phenotype of gastritis. In addition, the presence or absence of mucosal atrophy was taken into account. The relative risk for ulcer association with these conditions was calculated.

RESULTS

High-grade antral (SS > 5) associated with mild to moderate corpus (SS > 5) gastritis increased duodenal (RR = 4.9; confidence interval (CI), 2.8-8.5) and prepyloric ulcer risk (RR = 2.99; CI, 1.4-6.2). High-grade gastritis in the antrum (SS > 5) and corpus (SS > 5) increased gastric ulcer risk (RR = 3.7; CI, 1.6-8.3). Antral atrophy and/or intestinal metaplasia is associated with an increased gastric ulcer risk (RR = 3.3; CI, 1.4-7.8).

CONCLUSION

The pattern of H. pylori gastritis may define a risk for peptic ulcer at various sites, but additional factors, not reflected in histology, also contribute to this risk.

Helicobacter pylori vacuolating toxin accumulates within the endosomal-vacuolar compartment of cultured gastric cells and potentiates the vacuolating activity of ammonia

This study explored the relationship between vacuolating toxin and ammonia in the genesis of Helicobacter pylori-induced vacuolation in cultured human gastric cells and investigated the intracellular sites of toxin accumulation. Neutral red dye uptake and electron microscopy were used in the investigation of the respective roles of, and of the reciprocal interaction between, toxin and ammonia in cell vacuolation and ultrastructural immunocytochemistry was used for the identification of the intracellular sites of internalized toxin. Toxin was found to cause an expansion of the endosomal compartment, where it accumulates after cellular internalization. However, toxin does not form large, neutral red-positive vacuoles unless combined with ammonia, whose moderate vacuolating activity is markedly potentiated by the toxin. It is concluded that the toxin accumulated within the endosomal compartment alters the morphology and function of this organelle and plays a permissive role towards cell vacuolation, possibly by increasing the accumulation of protonated ammonia within endosomes. In turn, ammonia induces excessive dilatation of the endosomes with reciprocal fusion of their membranes, thus causing cytoplasmic vacuolation.

Vacuoles induced by Helicobacter pylori toxin contain both late endosomal and lysosomal markers

Intoxication of mammalian cells with the vacuolating toxin (VacA) released by Helicobacter pylori causes the formation of large acidic vacuoles containing the vacuolar ATPase proton pump and Rab7, a late endosome marker. Here, we describe a novel subcellular fractionation procedure, and we show that nanomolar concentrations of VacA induce a clear redistribution of lysosomal membrane glycoproteins among endocytic compartments. This redistribution is an early event in the process of cellular intoxication by VacA and precedes the formation of macroscopic vacuoles. The absence of the cation independent mannose 6-P receptor and the presence of Rab7 and of lysosomal membrane proteins in the newly formed compartment suggest that the vacuolating toxin induces the accumulation of a post-endosomal hybrid compartment presenting both late endosomal and lysosomal features.

Classification and grading of gastritis. The updated Sydney System. International Workshop on the Histopathology of Gastritis, Houston 1994

The Sydney System for the classification of gastritis emphasized the importance of combining topographical, morphological, and etiological information into a schema that would help to generate reproducible and clinically useful diagnoses. To reappraise the Sydney System 4 years after its introduction, a group of gastrointestinal pathologists from various parts of the world met in Houston, Texas, in September 1994. The aims of the workshop were (a) to establish an agreed terminology of gastritis; (b) to identify, define, and attempt to resolve some of the problems associated with the Sydney System. This article introduces the Sydney System as it was revised at the Houston Gastritis Workshop and represents the consensus of the participants. Overall, the principles and grading of the Sydney System were only slightly modified, the grading being aided by the provision of a visual analogue scale. The terminology of the final classification has been improved to emphasize the distinction between the atrophic and nonatrophic stomach; the names used for each entity were selected because they are generally acceptable to both pathologists and gastroenterologists. In addition to the main categories and atrophic and nonatrophic gastritis, the special or distinctive forms are described and their respective diagnostic criteria are provided. The article includes practical guidelines for optimal biopsy sampling of the stomach, for the use of the visual analogue scales for grading the histopathologic features, and for the formulation of a comprehensive standardized diagnosis. A glossary of gastritis-related terms as used in this article is provided.

Eradication of Helicobacter pylori and long-term outcome of functional dyspepsia. A clinical endoscopic study

The aim of this study was to assess the effect of colloidal bismuth subcitrate (CBS) and metronidazole on Helicobacter pylori eradication and on the course of symptoms due to functional dyspepsia. Forty-one patients with functional dyspepsia were entered into the study and randomized to treatment with CBS (120 mg four times a day) for four weeks combined with metronidazole (250 mg four times a day) for one week (group A, N = 21) or matching placebo (group B, N = 20). The severity of gastritis and of bacterial colonization and the symptom score was assessed by endoscopy and clinical evaluation at baseline and after four, eight, and 24 weeks from the start of the treatment. With intent-to-treat analysis eradication was achieved in 16/25 (64%) patients in group A and in 6/24 (25%) in group B. At eight and 24 weeks the gastritis score was significantly lower only in those patients with eradication. No change was seen in patients in whom the bacteria was not eradicated. The symptom score at eight weeks was considerably lower both in patients with eradication and in those with infection. However, at 24 weeks a gradual decrease in the symptom score in patients with eradication and a worsening of symptoms in controls was observed. No differences were observed between patients with ulcerlike and those with dysmotility-like dyspepsia. The study confirms the need for a long observation period after antibacterial treatment in patients with functional dyspepsia and suggests that Helicobacter pylori-eradicating treatment improves the course of this functional syndrome.

Histology of chronic gastritis with and without duodenitis in patients with Helicobacter pylori infection

AIM

To compare the histological characteristics of Helicobacter pylori positive chronic gastritis in patients with and without associated duodenitis.

METHODS

Gastric mucosal biopsy specimens were obtained from patients undergoing endoscopy for dyspepsia. Severity of gastritis and density of H pylori infection were graded according to the Sydney system.

RESULTS

Of the 69 patients studied, 15 had normal histology, 22 had chronic gastritis only (77.3% H pylori positive), 21 had duodenitis (90.5% H pylori positive), and 11 had other diagnoses. In the H pylori positive patients, the median gastritis score was higher in the duodenitis group (6, range 3-9) than in the chronic gastritis only group (5, range 2-8), because of greater neutrophil activity scores in patients with duodenitis (median score 2 v 1). There were no differences in the density of H pylori infection, inflammation, atrophy, or intestinal metaplasia between patients with chronic gastritis only and those with duodenitis.

CONCLUSIONS

These results suggest that H pylori positive patients with duodenitis have a more severe form of gastritis than those without associated duodenal inflammation. This is because of increased neutrophil activity, which seems to be independent of the density of H pylori infection.

Helicobacter pylori in promotion of gastric carcinogenesis

Gastric atrophy and intestinal metaplasia are considered the earliest phenotypic changes in the cascade of events leading from normal mucosa to intestinal-type gastric cancer, and epidemiological evidence links Helicobacter pylori to gastric epithelial malignancies. To evaluate any causal relationship between bacterial infection and atrophic metaplastic lesions, gastric pathology was histologically and histochemically evaluated in 267 consecutive, nonulcerous, untreated subjects, with attention given the phenotypes of intestinal metaplasia. The prevalence of Helicobacter pylori infection was 61%. Intestinal metaplasia (particularly types II and III) was significantly associated with both Helicobacter pylori detection (chi 2 LR: P < 0.002) and increasing age (chi 2 LR: P < 0.002). Using logistic regression analysis, the development of intestinal metaplasia proved more significantly linked with Helicobacter pylori infection [odds ratio = 4.55 (95% confidence interval: 1.51-13.7)], than with age [odds ratio = 1.03 (95% CI: 1.01-1.06)], with no interaction. In conclusion, Helicobacter pylori can be considered among the major causal agents of mucosal lesions involved in the multistep process of gastric carcinogenesis, justifying any attempt to eradicate this bacterial infection.

Helicobacter pylori infection and its role in human disease--an overview

Helicobacter pylori (H. pylori) is probably the commonest chronic bacterial infection in humans. The bacterium colonizes the gastric epithelium and induces inflammation of the underlying mucosa. The recognition that this infection is the most important acquired factor in the pathogenesis of duodenal and gastric ulcers has transformed the management of these common disorders. Most patients with ulcers can be cured by a 1-week course of anti-H. pylori therapy, thereby removing the need for long-term acid inhibitory therapy. Eradication of the infection involves taking complex combinations of drugs and simpler eradication regimens are required. Recent epidemiological data indicate an association between H. pylori infection and the subsequent development of gastric carcinoma. If this association is established as causal, then widespread eradication of the infection may be indicated. Global eradication of H. pylori will probably rely on prophylactic or therapeutic vaccination and this approach is being actively investigated.

Intestinal and diffuse gastric cancers arise in a different background of Helicobacter pylori gastritis through different gene involvement

Investigation of extensively sampled nontumor gastric mucosa from 205 early gastric cancers showed Helicobacter pylori colonization in 85% of cases, including 100% of diffuse and 78% (83% in 97 cases with Swiss rolls) of glandular or mixed cancers. Intestinal metaplasia, including its type III variant, was prominent in the mucosa associated with glandular and mixed (but not diffuse) early cancers. Both glandular (usually called "intestinal") and diffuse-type cancers showed admixtures of intestinal and gastric tumor cell phenotypes. Both p53 gene mutations and p53 protein immunostaining were essentially restricted to glandular or mixed cancers and associated dysplastic lesions. Their appearance in the advanced stage of diffuse cancer was partly due to a change of the histologic pattern from glandular to diffuse during progression of some tumors. Loss of laminin, beta I integrin, or zonula adherens junctions was a common finding in both early and advanced diffuse cancer. It is concluded that two main pathways operate in gastric carcinogenesis, both starting from H. pylori gastritis and both leading to phenotypically variable, often mixed gastric/intestinal tumor growth. However, only one of the two pathways involves intestinal metaplasia, its type III variant, p53 gene alteration, and dysplasia to end in glandular cancer. In the other pathway, diffuse cancer apparently arises directly from hyperplastic, sometimes atypical necks of mostly nonmetaplastic gastric glands, through primary involvement of genes affecting cell-cell and cell-matrix junctional proteins.

Effects of permanent eradication or transient clearance of Helicobacter pylori on histology of gastric mucosa using omeprazole with or without antibiotics

Changes in Helicobacter pylori-associated gastritis of the antrum and corpus were investigated in a large number of patients treated with omeprazole, with or without the addition of amoxycillin. To investigate the role of H. pylori-associated gastritis in ulcerogenesis and its interplay with omeprazole, biopsies were taken and evaluated according to the Sydney system. Successful eradication of H. pylori (assessed histologically 4 weeks after the end of therapy) led to prompt and persistent suppression of gastritis activity, slow, partial regression of mononuclear inflammation and an ulcer recurrence rate of only 14% during the 6 months' follow-up. In patients treated with omeprazole and placebo, or where eradication treatment with omeprazole and amoxycillin had failed, transient clearance of H. pylori from the antral (but not oxyntic) mucosa was seen. In both of these groups of patients transient regression in the antrum, and worsening in the corpus, of gastritis activity and mononuclear inflammation were evident, coupled with ulcer recurrence rates of 72 and 46%, respectively. It was concluded that H. pylori colonization and gastritis activity play a crucial role in ulcerogenesis, that acid inhibition treatment improves antral H. pylori gastritis and worsens the oxyntic mucosal gastritis, and that this can be prevented by eradication of the H. pylori infection.