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

Practice Trends among US Gastroenterologists following the 2020 American Gastroenterological Association Guidelines on Gastric Intestinal Metaplasia: Data from a Tertiary Care Center

BACKGROUND AND AIMS

Studies show variability in gastroenterologists' management of gastric intestinal metaplasia (GIM) in the United States. In 2020, the American Gastroenterological Association published GIM guidelines, recommending physician-patient shared decision-making on GIM surveillance based on risk factors. We compared gastroenterologists' communication trends of a GIM finding and surveillance recommendations before and after 2020 and evaluated patient and provider factors associated with a surveillance recommendation.

METHODS

A sample of patients diagnosed with GIM on biopsies from upper endoscopies performed in 2018 (cohort A) and 2021 (cohort B) were included. Logistic regression analysis assessed the association between patient/provider characteristics and surveillance recommendations in the overall cohort and over time.

MATERIALS

In all, 347 patients were included: 175 in cohort A and 172 in B. Median age was 65.7 (56.0, 73.4), and 54.5% were females. Communication to patients about GIM findings and surveillance recommendations increased from 24.6% <2020 to 50% >2020 ( P <0.001) and 20% <2020 to 41.3% >2020 ( P <0.001), respectively. Overall, endoscopy >2020, family history of gastric cancer, autoimmune gastritis, female providers, and gastroenterologists with 10 to 20 years of experience were associated with a surveillance recommendation. The effect of family history of gastric cancer and the effect of the patient's female sex on surveillance was significantly different between both cohorts [Odds ratio (OR): 0.13, 95% (Confidence interval) CI: 0.02, 0.97 and OR 3.39, 95% CI: 1.12, 10.2, respectively).

CONCLUSIONS

Despite a 2-fold increase in surveillance recommendations after 2020, there was no meaningful effect of any of the patients' factors on a recommendation for surveillance over time, which raises the question as to whether surveillance is being offered to both average and high-risk patients without thorough risk stratification.

The endoscopic model for gastric carcinogenesis and Helicobacter pylori infection: A potential visual mind-map during gastroscopy examination

Helicobacter pylori (Hp) is the main trigger of chronic gastric atrophy and the main leading cause of gastric cancer. Hp infects the normal gastric mucosa and can lead to chronic inflammation, glandular atrophy, intestinal metaplasia, dysplasia and finally adenocarcinoma. Chronic inflammation and gastric atrophy associated with Hp infection appear initially in the distal part of the stomach (the antrum) before progressing to the proximal part (the corpus-fundus). In recent years, endoscopic developments have allowed for the characterization of various gastric conditions including the normal mucosa (pyloric/fundic gland pattern and regular arrangement of collecting venules), Hp-related gastritis (Kyoto classification), glandular atrophy (Kimura-Takemoto classification), intestinal metaplasia (Endoscopic Grading of Gastric Intestinal Metaplasia), and dysplasia/adenocarcinoma (Vessel plus Surface classification). Despite being independent classifications, all these scales can be integrated into a single model: the endoscopic model for gastric carcinogenesis. This model would assist endoscopists in comprehending the process of gastric carcinogenesis and conducting a systematic examination during gastroscopy. Having this model in mind would enable endoscopists to promptly recognize the implications of Hp infection and the potential patient's risk of developing gastric cancer.

Prevalence of Gastric Precursor Lesions in Countries With Differential Gastric Cancer Burden: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

The prevalence of precursor lesions for gastric cancer (GC) and the differential burden between countries of varying GC risk is not well-understood. We conducted a systematic review and meta-analysis to estimate the global prevalence of precursor lesions.

METHODS

We estimated the prevalence of atrophic gastritis (AG), gastric intestinal metaplasia (IM), and dysplasia in regions with low, medium, and high GC incidence. Because IM is an advanced manifestation of AG, we assessed the prevalence of less advanced precursors, regardless of the presence of more advanced lesions. Prevalence was sub-stratified by Helicobacter pylori infection, symptomatology, and period (<2000, 2000-2010, and >2010).

RESULTS

Among the 582 articles that underwent full-text review, 166 studies met inclusion criteria. The global prevalence estimates of AG, IM, and dysplasia were 25.4%, 16.2%, and 2.0%, respectively, on the basis of 126 studies that reported the prevalence of less advanced precursors, regardless of the presence of more advanced lesions. The prevalence of all precursor lesions was higher in high and medium compared with low GC incidence countries (P < .01). Prevalence of AG and IM was significantly higher among H pylori-infected individuals (P < .01) but not statistically different between symptomatic and asymptomatic individuals (P > .17). All precursors demonstrated a secular decrease in prevalence over time.

CONCLUSIONS

Gastric precursor lesions have differences in prevalence in regions with differential GC incidence and are associated with H pylori infection. Because of the substantial prevalence of precursor lesions in both symptomatic and asymptomatic individuals, symptomatic evaluation may not be sufficient to identify individuals at risk. These estimates provide important insights for tailoring GC prevention strategies.

Gastric intestinal metaplasia: Prevalence in a large Australian center and nationwide survey of endoscopic practice

Background and Aim

Atrophic gastritis (AG) and gastric intestinal metaplasia (GIM) are early changes in the stepwise progression to gastric adenocarcinoma. There is heterogeneity in international guidelines regarding the endoscopic diagnosis and surveillance of AG and GIM. This study aims to determine the prevalence of GIM in an Australian center and assess the approach of Australian endoscopists for these two conditions.

Methods

We conducted a single-center retrospective study of adult patients between January 2015 and December 2020 diagnosed with GIM on gastric biopsy following upper gastric endoscopy. A web-based, 25-question, investigator-designed, multiple-choice survey was distributed among all registered endoscopists in Australia.

Results

The overall prevalence of GIM within a single Australian center was 11.7% over 5 years. Of the 1026 patients identified, only 58.7% underwent mapping biopsies using the modified Sydney protocol. Among the cohort, 1.6% had low-grade dysplasia, 0.9% had high-grade dysplasia, and 1.8% had malignancy on initial gastroscopy. Two hundred and sixty-seven (7.2%) endoscopists completed the survey, 44.2% indicated they would perform mapping for all patients, and 36% only for high-risk patients. Only 1.5% (n = 4) of respondents were able to correctly identify all six endoscopic photos of GIM/AG.

Conclusion

This study demonstrates that in a large tertiary center, GIM is a prevalent endoscopic finding, but the associated rates of dysplasia and cancer were low. Additionally, among a small proportion of surveyed Australian endoscopists, there is notable variability in the endoscopic approach for AG and GIM and significant knowledge gaps. More training is required to increase the recognition of GIM and compliance with histological mapping.

Remodeling of the gastric environment in Helicobacter pylori-induced atrophic gastritis

Helicobacter pylori colonization of the human stomach is a strong risk factor for gastric cancer. To investigate H. pylori-induced gastric molecular alterations, we used a Mongolian gerbil model of gastric carcinogenesis. Histologic evaluation revealed varying levels of atrophic gastritis (a premalignant condition characterized by parietal and chief cell loss) in H. pylori-infected animals, and transcriptional profiling revealed a loss of markers for these cell types. We then assessed the spatial distribution and relative abundance of proteins in the gastric tissues using imaging mass spectrometry and liquid chromatography with tandem mass spectrometry. We detected striking differences in the protein content of corpus and antrum tissues. Four hundred ninety-two proteins were preferentially localized to the corpus in uninfected animals. The abundance of 91 of these proteins was reduced in H. pylori-infected corpus tissues exhibiting atrophic gastritis compared with infected corpus tissues exhibiting non-atrophic gastritis or uninfected corpus tissues; these included numerous proteins with metabolic functions. Fifty proteins localized to the corpus in uninfected animals were diffusely delocalized throughout the stomach in infected tissues with atrophic gastritis; these included numerous proteins with roles in protein processing. The corresponding alterations were not detected in animals infected with a H. pylori ∆cagT mutant (lacking Cag type IV secretion system activity). These results indicate that H. pylori can cause loss of proteins normally localized to the gastric corpus as well as diffuse delocalization of corpus-specific proteins, resulting in marked changes in the normal gastric molecular partitioning into distinct corpus and antrum regions.IMPORTANCEA normal stomach is organized into distinct regions known as the corpus and antrum, which have different functions, cell types, and gland architectures. Previous studies have primarily used histologic methods to differentiate these regions and detect H. pylori-induced alterations leading to stomach cancer. In this study, we investigated H. pylori-induced gastric molecular alterations in a Mongolian gerbil model of carcinogenesis. We report the detection of numerous proteins that are preferentially localized to the gastric corpus but not the antrum in a normal stomach. We show that stomachs with H. pylori-induced atrophic gastritis (a precancerous condition characterized by the loss of specialized cell types) exhibit marked changes in the abundance and localization of proteins normally localized to the gastric corpus. These results provide new insights into H. pylori-induced gastric molecular alterations that are associated with the development of stomach cancer.

The Impact of the Angulus Biopsy on the Detection of Staging and the Grading of Chronic Gastritis

There is a generally recognized need for a morphological assessment of the individual risk of developing gastric cancer in a patient with chronic gastritis, according to the OLGA system (Operative Link for Gastritis Assessment). At the same time, the role of assessing the biopsy from the incisura angularis remains controversial. The aim of our study was to assess the value of incisura angularis biopsy in staging gastritis according to the OLGA system by examining the atrophic and inflammatory changes in the antrum, incisura angularis, and body.

MATERIALS AND METHODS

A total of 718 patients (576 women and 142 men) aged 20 to 84 years were examined. Most of the patients were in the age group of 50 to 70 years (54.6%). Depending on the detection of H. pylori and autoimmune gastritis markers, all patients were divided into three groups. The first group included 380 patients with H. pylori gastritis without signs of autoimmune gastritis. The second group consisted of 209 patients with autoimmune gastritis, in whom no infection was detected during the examination, and there were no indications of H. pylori eradication. The third group consisted of 129 patients with chronic gastritis of combined etiology (autoimmune and H. pylori). Endoscopy biopsies were taken according to the updated Sydney System. Histological assessments of the grade and the stage of gastritis were carried out according to the standard OLGA-based protocol. Then, the same assessments were evaluated without taking into account histological changes in the incisura angularis.

RESULTS

When assessing the severity of inflammatory changes in the gastric mucosa according to the OLGA system, grade II (72.3%) was most often detected in all groups of patients. A severe degree of activity of chronic gastritis was most often observed in the group of patients with H. pylori gastritis (6.1%). These indicators practically did not change if the assessment did not take the angulus biopsy into account. When assessing the severity of atrophy of the glands in the gastric mucosa in patients of the first group, mild stages of atrophy prevailed. Without taking into account the angulus biopsy, a decrease in the stage of atrophy was observed in 27 cases (7.11%), and in only 4 cases did stage IV change to stage III, while in 23 cases, discrepancies were noted only within groups with a mild stage of atrophy. There were no transitions from stage III to stage II. In the group of patients with autoimmune gastritis, pronounced stages of atrophy prevailed-in more than 77%. Without taking into account the angulus biopsy, a decrease in the stage of atrophy was observed in eight cases (3.83%), and in three (1.4%) patients, stage III was changed to stage II. In the group of patients with combined etiology (autoimmune + H. pylori), severe stages of atrophy also prevailed (70.5%). A decrease in the stage of atrophy without taking into account the angulus biopsy was only observed in three patients (2.32%), of which two cases concerned patients with mild stages of atrophy. Thus, in general, severe stages of atrophy of the gastric mucosa (stages III and IV according to the OLGA staging system) were detected in 313 patients (43.59%). If the assessment of the atrophy stage did not take into account changes in the angulus biopsy, then severe stages of atrophy (III and IV according to OLGA) were detected in 310 patients (43.17%). In total, changes in the assessment of the atrophy stage occurred in 38 patients (5.29%), and this was more often observed in patients with stages I and II of atrophy.

CONCLUSIONS

Accounting for histological changes in the incisura angularis does not significantly affect the assessment of the grade and stage of chronic gastritis according to the OLGA system, regardless of the etiology of atrophic gastritis.

Clinical Pathogenesis, Molecular Mechanisms of Gastric Cancer Development

The human pathogen Helicobacter pylori is the strongest known risk factor for gastric disease and cancer, and gastric cancer remains a leading cause of cancer-related death across the globe. Carcinogenic mechanisms associated with H. pylori are multifactorial and are driven by bacterial virulence constituents, host immune responses, environmental factors such as iron and salt, and the microbiota. Infection with strains that harbor the cytotoxin-associated genes (cag) pathogenicity island, which encodes a type IV secretion system (T4SS) confer increased risk for developing more severe gastric diseases. Other important H. pylori virulence factors that augment disease progression include vacuolating cytotoxin A (VacA), specifically type s1m1 vacA alleles, serine protease HtrA, and the outer-membrane adhesins HopQ, BabA, SabA and OipA. Additional risk factors for gastric cancer include dietary factors such as diets that are high in salt or low in iron, H. pylori-induced perturbations of the gastric microbiome, host genetic polymorphisms, and infection with Epstein-Barr virus. This chapter discusses in detail host factors and how H. pylori virulence factors augment the risk of developing gastric cancer in human patients as well as how the Mongolian gerbil model has been used to define mechanisms of H. pylori-induced inflammation and cancer.

Autoimmune gastritis: long-term natural history in naïve Helicobacter pylori-negative patients

OBJECTIVE

Autoimmune gastritis (AIG) is an immunomediated disease targeting parietal cells, eventually resulting in oxyntic-restricted atrophy. This long-term follow-up study aimed at elucidating the natural history, histological phenotype(s), and associated cancer risk of patients with AIG consistently tested H. pylori-negative (naïve H. pylori-negative subjects).

DESIGN

Two-hundred eleven naïve H. pylori-negative patients (tested by serology, histology, molecular biology) with AIG (F:M=3.15:1; p<0.001) were prospectively followed up with paired biopsies (T1 vs T2; mean follow-up years:7.5 (SD:4.4); median:7). Histology distinguished non-atrophic versus atrophic AIG. Atrophy was further subtyped/scored as non-metaplastic versus metaplastic (pseudopyloric (PPM) and intestinal (IM)). Enterochromaffin-like-cell (ECL) status was categorised as diffuse versus adenomatoid hyperplasia/dysplasia, and type 1 neuroendocrine tumours (Type1-NETs).

RESULTS

Over the long-term histological follow-up, AIG consistently featured oxyntic-predominant-mononuclear inflammation. At T1, PPM-score was greater than IM (200/211 vs 160/211, respectively); IM scores increased from T1 to T2 (160/211 to 179/211), with no changes in the PPM prevalence (T1=200/211; T2=201/211). At both T1/T2, the prevalence of OLGA-III-stage was <5%; no Operative Link on Gastritis Assessment (OLGA)-IV-stage occurred. ECL-cell-status progressed from diffuse to adenomatoid hyperplasia/dysplasia (T1=167/14 vs T2=151/25). Type1-NETs (T1=10; T2=11) always coexisted with extensive oxyntic-atrophy, and ECL adenomatoid-hyperplasia/dysplasia. No excess risk of gastric or other malignancies was found over a cumulative follow-up time of 10 541 person years, except for (marginally significant) thyroid cancer (SIR=3.09; 95% CI 1.001 to 7.20).

CONCLUSIONS

Oxyntic-restricted inflammation, PPM (more than IM), and ECL-cell hyperplasia/neoplasia are the histological AIG hallmarks. Compared with the general population, corpus-restricted inflammation/atrophy does not increase the GC risk. The excess of GC risk reported in patients with AIG could plausibly result from unrecognised previous/current H. pylori comorbidity.

Predicting Gastric Intestinal Metaplasia in a High-Risk Population

INTRODUCTION

Gastric intestinal metaplasia (GIM) is a precancerous lesion. It has a low prevalence rate in the United States. However, GIM is more common among non-White and immigrant populations. Harlem Hospital serves a community that includes predominantly African Americans, Hispanics, and immigrants from West Africa and Spanish-speaking Caribbean countries. This study aims to define the factors predicting GIM in this high-risk group as well as help define screening strategies for vulnerable populations.

METHODS

A total of 1351 patients who underwent endoscopic gastroduodenoscopy (EGD) and biopsy in 2018 and 2019 for any indication at Harlem Hospital were included in this study. Gastric biopsy specimens taken during the procedure were assessed for GIM by histopathology. Baseline demographics were collected, including age, sex, and ethnicity. Other information collected included risk factors for GIM such as Helicobacter pylori infection, smoking status, and the use of alcohol. Descriptive analysis was done and the Wilcoxon rank sum test and chi-squared test were used to test for associations. Multiple logistic regressions were used to assess the odds of independent factors associated with increased risk of GIM.

RESULTS

Of the 1351 patients reviewed, 106 had GIM for a prevalence of 8.0% (CI: 6.7%-9.6%, p < 0.001). Univariate analysis revealed older patients, males, history of smoking, alcohol, and H. pylori infection were significantly associated with GIM. Using multiple logistic regressions and adjusting for underlying risk factors, smoking (OR: 1.61, 95% CI: 1.00-2.570) and H. pylori infection (OR: 3.35, 95% CI: 2.18-5.15) continued to be significantly associated with increased risk of GIM; however, alcohol use was not significant after adjusting for other risk factors (OR: 1.10, 95% CI: 0.68-1.78). Hispanic risk for GIM was slightly higher than African Americans (OR: 1.17, 95% CI: 0.74-1.83). The predicted marginal effect of age on the odds of GIM was significant from age 40 and increased exponentially at age 50. By age 70, the odds of GIM were as high as 11% (95% CI: 8.3-13.6).

CONCLUSION

The prevalence of GIM in our population is significantly higher compared to reported cases in the United States. Age, male gender, H. pylori infection, and smoking significantly increase the risk of GIM. Given the high prevalence of GIM in our population, early endoscopic screening would play an important role in evaluating dyspepsia to diagnose GIM with or without H. pylori infection. We propose screening all at-risk ethnicities from age 40 years with EGD according to the Sydney System biopsy protocol. We believe this will ultimately decrease the incidence of gastric cancer death in these vulnerable populations of color.

Bile reflux and bile acids in the progression of gastric intestinal metaplasia

ABSTRACT

Gastric intestinal metaplasia (GIM) is a precancerous lesion of gastric cancer (GC) and is considered an irreversible point of progression for GC. Helicobacter pylori infection can cause GIM, but its eradication still does not reverse the process. Bile reflux is also a pathogenic factor in GIM and can continuously irritate the gastric mucosa, and bile acids in refluxed fluid have been widely reported to be associated with GIM. This paper reviews in detail the relationship between bile reflux and GIM and the mechanisms by which bile acids induce GIM.

Pernicious Anemia: The Hematological Presentation of a Multifaceted Disorder Caused by Cobalamin Deficiency

Pernicious anemia is still a neglected disorder in many medical contexts and is underdiagnosed in many patients. Pernicious anemia is linked to but different from autoimmune gastritis. Pernicious anemia occurs in a later stage of autoimmune atrophic gastritis when gastric intrinsic factor deficiency and consequent vitamin B₁₂ deficiency may occur. The multifaceted nature of pernicious anemia is related to the important role of cobalamin, which, when deficient, may lead to several dysfunctions, and thus, the proteiform clinical presentations of pernicious anemia. Indeed, pernicious anemia may lead to potentially serious long-term complications related to micronutrient deficiencies and their consequences and the development of gastric cancer and type 1 gastric neuroendocrine tumors. When not recognized in a timely manner or when pernicious anemia is diagnosed with delay, these complications may be potentially life-threatening and sometimes irreversible. The current review aimed to focus on epidemiology, pathogenesis, and clinical presentations of pernicious anemia in an attempt to look beyond borders of medical specialties. It aimed to focus on micronutrient deficiencies besides the well-known vitamin B₁₂ deficiency, the diagnostic approach for pernicious anemia, its long-term complications and optimal clinical management, and endoscopic surveillance of patients with pernicious anemia.

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.

Pseudopyloric Metaplasia Is Not Associated With the Development of Gastric Cancer

INTRODUCTION

Corpus atrophic gastritis (CAG) is associated with intestinal metaplasia (IM) and pseudopyloric metaplasia (PPM). Prospective data on corpus mucosa PPM and its link to the development of gastric cancer (GC) are lacking. This study aimed to investigate the relationship between the presence of corpus mucosa PPM at baseline and the development of GC at follow-up in patients with CAG.

METHODS

A longitudinal cohort study was conducted on patients with consecutive CAG adhering to endoscopic-histological surveillance. Patients were stratified for the presence/absence of corpus PPM without concomitant corpus IM at baseline, and the occurrence of gastric neoplastic lesions at the longest available follow-up was assessed.

RESULTS

A total of 292 patients with CAG with a follow-up of 4.2 (3-17) years were included. At baseline, corpus PPM without corpus IM was diagnosed in 62 patients (21.2%). At the follow-up, GC was detected in 5 patients (1.7%) and gastric dysplasia (GD) in 4 patients (1.4%). In all these 9 patients with GC/GD at the follow-up, corpus IM was present at baseline and follow-up. Age <50 years (odds ratio [OR] 2.5), absence of pernicious anemia (OR 4.3), and absence of severe corpus atrophy (OR 2.3) were associated with corpus PPM without corpus IM.

DISCUSSION

At the 4.2-year follow-up, in patients with CAG characterized at baseline with corpus PPM without corpus IM, GC or GD was not observed because these lesions were consistently associated with corpus IM. Corpus PPM without corpus IM was associated with younger age, absence of pernicious anemia, and severe corpus atrophy, suggesting a lower stage of disease progression. Corpus PPM alone seems not to be associated with GC, whose development seems to require the presence of corpus IM as a necessary step.

The Different Clinicopathological Features of Remnant Gastric Cancer Depending on Initial Disease of Partial Gastrectomy

Background: The incidence of gastric cancer increases in the remnant stomach after partial gastrectomy; however, its pathogenesis remains controversial. The clinicopathological features and immunohistochemical subtype were evaluated in patients with remnant gastric cancer considering the initial cause of partial gastrectomy. Methods: We categorized 59 cases of remnant gastric cancer who underwent curative surgery between 2001 and 2016 according to initial pathologies of benign (n = 24) or malignant (n = 35). Histological changes including pyloric metaplasia and intestinal metaplasia in the mucosa around the anastomosis site and the background mucosa of carcinomas were compared between the groups. Results: In the malignant group, the proportion of male patients was substantially lower, with a shorter interval. In background mucosa around the carcinomas, incidence of high-grade pyloric metaplasia was significantly higher in the benign group (13/20, 65.0% vs. 10/28, 35.7%), while high-grade intestinal metaplasia was only observed in the malignant group (0/20, 0% vs. 7/28, 25.0%). Conclusions: The cancers in the initial benign disease are mainly associated with pyloric metaplasia at the anastomosis site, reflecting reflux, but not with intestinal metaplasia. On the other hand, in the initial malignant disease group, intestinal metaplasia has an equally important role as reflux-associated pyloric metaplasia.

Acid and the basis for cellular plasticity and reprogramming in gastric repair and cancer

Subjected to countless daily injuries, the stomach still functions as a remarkably efficient digestive organ and microbial filter. In this Review, we follow the lead of the earliest gastroenterologists who were fascinated by the antiseptic and digestive powers of gastric secretions. We propose that it is easiest to understand how the stomach responds to injury by stressing the central role of the most important gastric secretion, acid. The stomach follows two basic patterns of adaptation. The superficial response is a pattern whereby the surface epithelial cells migrate and rapidly proliferate to repair erosions induced by acid or other irritants. The stomach can also adapt through a glandular response when the source of acid is lost or compromised (that is, the process of oxyntic atrophy). We primarily review the mechanisms governing the glandular response, which is characterized by a metaplastic change in cellular differentiation known as spasmolytic polypeptide-expressing metaplasia (SPEM). We propose that the stomach, like other organs, exhibits marked cellular plasticity: the glandular response involves reprogramming mature cells to serve as auxiliary stem cells that replace lost cells. Unfortunately, such plasticity might mean that the gastric epithelium undergoes cycles of differentiation and de-differentiation that increase the risk of accumulating cancer-predisposing mutations.

Genomic and Epigenomic Profiling of High-Risk Intestinal Metaplasia Reveals Molecular Determinants of Progression to Gastric Cancer

Intestinal metaplasia (IM) is a pre-malignant condition of the gastric mucosa associated with increased gastric cancer (GC) risk. We performed (epi)genomic profiling of 138 IMs from 148 cancer-free patients, recruited through a 10-year prospective study. Compared with GCs, IMs exhibit low mutational burdens, recurrent mutations in certain tumor suppressors (FBXW7) but not others (TP53, ARID1A), chromosome 8q amplification, and shortened telomeres. Sequencing identified more IM patients with active Helicobacter pylori infection compared with histopathology (11%-27%). Several IMs exhibited hypermethylation at DNA methylation valleys; however, IMs generally lack intragenic hypomethylation signatures of advanced malignancy. IM patients with shortened telomeres and chromosomal alterations were associated with subsequent dysplasia or GC; conversely patients exhibiting normal-like epigenomic patterns were associated with regression.

Preferential location of idiopathic peptic ulcers

OBJECTIVE

Helicobacter pylori infection-negative, nonsteroidal antiinflammatory drugs (NSAIDs)-negative peptic ulcers, which are termed idiopathic peptic ulcers (IPUs), have been increasing worldwide. In this study, we investigated the preferential locations of gastric ulcers according to their cause (e.g., H. pylori and NSAIDs), with special attention to IPUs.

MATERIAL AND METHODS

A total of 361 patients consecutively diagnosed with a peptic ulcer over a period of one year were classified into four groups according to H. pylori-infection status and NSAIDs usage. The ulcer location was divided into the antrum, angularis, and body, and was compared among the four ulcer groups.

RESULTS

The ulcers of 43 patients were classified as IPUs. Compared with simple H. pylori ulcers, IPUs more preferentially located in the antrum (14% vs. 52%, p < 0.01). The difference was more pronounced in the analysis of IPUs in which patients with a history of H. pylori eradication or those with severe atrophic gastritis were excluded, and 79% of these IPUs were located in the antrum. With duodenal ulcers taken together, the vast majority of (86%) these IPUs occurred in the duodenal bulb or the antrum. The proportion of antral ulcers in NSAISs users also differed depending on the presence of concomitant H. pylori infection (positive: 22% vs. negative: 62%, p < 0.01).

CONCLUSION

There was a striking difference in the ulcer location within the stomach depending on the cause of the ulcer, and IPUs predominantly occurred in the antrum. This information on the preferential locations of ulceration should provide endoscopists with some hints concerning the etiology of ulcers.

Safety of proton pump inhibitors and risk of gastric cancers: review of literature and pathophysiological mechanisms

INTRODUCTION

Despite being an overall safe drug, several long-term adverse effects are associated with proton pump inhibitors (PPIs). The link between PPI use and gastric neuroendocrine tumors (NETs), gastric adenocarcinomas and Barrett's esophagus progression gastric cancers has been investigated due to PPI-induced hypergastrinemia.

AREAS COVERED

The pathophysiological mechanisms underlying PPI exposure and gastric NETs, gastric adenocarcinomas and Barrett's esophagus progression are discussed. The quality of randomized control studies, cohort studies and case reports investigating the link between gastric cancers and PPIs are examined. Recommendations for clinicians are provided.

EXPERT OPINION

PPIs cause a hypergastrinemic state, increasing enterochromaffin-like cell dysplasia and risk of gastric NET development, increasing gastritis severity in the context of Helicobacter pylori infection, and progression of carcinogenesis in a certain predisposed subset of Barrett's esophagus patients. There are case reports of PPI-induced gastric NETs and adenocarcinomas as consequences of these effects. In pernicious anemia and chronic gastritis, clinicians should be aware of potential increased risk of gastric NET development with chronic PPI use in these patients. Eradication status of H. pylori prior to commencing long-term PPI therapy should be established to reduce the risk of severe atrophic gastritis and development of gastric dysplasia.

Detection of gastric precancerous conditions in daily clinical practice: a nationwide survey

BACKGROUND

The burden of gastric precancerous conditions and factors associated with their detection have not been fully investigated in community-based settings. Little is known about adherence to Sydney system for histopathology of gastric biopsies.

OBJECTIVE

We aimed to investigate what really happens in clinical practice with regard to the detection of gastric atrophy and intestinal metaplasia in dyspeptic patients.

METHODS

We performed a nationwide survey of 979 consecutive patients (50-65 years old) with dyspeptic symptoms, examined at 24 gastrointestinal endoscopy units throughout Italy. Clinical information was collected from questionnaires; a standard bioptic mapping was performed in each unit, biopsies from each patient were analyzed by histopathology performed according to daily clinical practice in each local histopathology center.

RESULTS

Separate descriptions of antral and corporal biopsies were included in 679 pathology reports (69%), whereas Sydney system was applied in 324 reports (33%). Gastric atrophy without intestinal metaplasia (GA) and gastric atrophy with intestinal metaplasia (GIM) were detected in 322 (33%) patients. The full adherence to Sydney system significantly increased the probability of detecting GIM (OR 9.6, 95% CI 5.5-16.7), GA (OR 1.92, 95% CI 1.07-3.44), and either of the conditions (OR 6.67, 95% CI 4.36-10.19).

CONCLUSIONS

This nationwide survey showed that in one-third of dyspeptic patients, gastric precancerous conditions are detected. In daily routine practice, only 1/3 of histology reports were worked out adhering to Sydney system showing that international guidelines are poorly observed in clinical practice. This may represent a critical element for surveillance strategies for gastric cancer.

Modelling human development and disease in pluripotent stem-cell-derived gastric organoids

Gastric diseases, including peptic ulcer disease and gastric cancer, affect 10% of the world’s population and are largely due to chronic H. pylori infection^1–3. Species differences in embryonic development and architecture of the adult stomach make animal models suboptimal for studying human stomach organogenesis and pathogenesis⁴, and there is no experimental model of normal human gastric mucosa. Here we report the de novo generation of three-dimensional human gastric tissue in vitro through the directed differentiation of human pluripotent stem cells (hPSCs). We identified that temporal manipulation of the FGF, WNT, BMP, retinoic acid and EGF signaling pathways and three-dimensional growth are sufficient to generate human gastric organoids (hGOs). Developing hGOs progressed through molecular and morphogenetic stages that were nearly identical to the developing antrum of the mouse stomach. Organoids formed primitive gastric gland- and pit-like domains, proliferative zones containing LGR5-expressing cells, surface and antral mucous cells, and a diversity of gastric endocrine cells. We used hGO cultures to identify novel signaling mechanisms that regulate early endoderm patterning and gastric endocrine cell differentiation upstream of the transcription factor NEUROG3. Using hGOs to model pathogenesis of human disease, we found that H. pylori infection resulted in rapid association of the virulence factor CagA with the c-Met receptor, activation of signaling and induction of epithelial proliferation. Together, these studies describe a novel and robust in vitro system for elucidating the mechanisms underlying human stomach development and disease.

Establishment of novel in vitro mouse chief cell and SPEM cultures identifies MAL2 as a marker of metaplasia in the stomach

Oxyntic atrophy in the stomach leads to chief cell transdifferentiation into spasmolytic polypeptide expressing metaplasia (SPEM). Investigations of preneoplastic metaplasias in the stomach are limited by the sole reliance on in vivo mouse models, owing to the lack of in vitro models for distinct normal mucosal lineages and metaplasias. Utilizing the Immortomouse, in vitro cell models of chief cells and SPEM were developed to study the characteristics of normal chief cells and metaplasia. Chief cells and SPEM cells isolated from Immortomice were cultured and characterized at both the permissive (33°C) and the nonpermissive temperature (39°C). Clones were selected on the basis of their transcriptional expression of specific stomach lineage markers (named ImChief and ImSPEM) and protein expression and growth were analyzed. The transcriptional expression profiles of ImChief and ImSPEM cells were compared further by using gene microarrays. ImChief cells transcriptionally express most chief cell markers and contain pepsinogen C and RAB3D-immunostaining vesicles. ImSPEM cells express the SPEM markers TFF2 and HE4 and constitutively secrete HE4. Whereas ImChief cells cease proliferation at the nonpermissive temperature, ImSPEM cells continue to proliferate at 39°C. Gene expression profiling of ImChief and ImSPEM revealed myelin and lymphocyte protein 2 (MAL2) as a novel marker of SPEM lineages. Our results indicate that the expression and proliferation profiles of the novel ImChief and ImSPEM cell lines resemble in vivo chief and SPEM cell lineages. These cell culture lines provide the first in vitro systems for studying the molecular mechanisms of the metaplastic transition in the stomach.

Transcriptome signatures in Helicobacter pylori-infected mucosa identifies acidic mammalian chitinase loss as a corpus atrophy marker

Background

The majority of gastric cancer cases are believed to be caused by chronic infection with the bacterium Helicobacter pylori, and atrophic corpus gastritis is a predisposing condition to gastric cancer development. We aimed to increase understanding of the molecular details of atrophy by performing a global transcriptome analysis of stomach tissue.

Methods

Biopsies from patients with different stages of H. pylori infection were taken from both the antrum and corpus mucosa and analyzed on microarrays. The stages included patients without current H. pylori infection, H. pylori-infected without corpus atrophy and patients with current or past H. pylori-infection with corpus-predominant atrophic gastritis.

Results

Using clustering and integrated analysis, we found firm evidence for antralization of the corpus mucosa of atrophy patients. This antralization harbored gain of gastrin expression, as well as loss of expression of corpus-related genes, such as genes associated with acid production, energy metabolism and blood clotting. The analyses provided detailed molecular evidence for simultaneous intestinal metaplasia (IM) and spasmolytic polypeptide expressing metaplasia (SPEM) in atrophic corpus tissue. Finally, acidic mammalian chitinase, a chitin-degrading enzyme produced by chief cells, was shown to be strongly down-regulated in corpus atrophy.

Conclusions

Transcriptome analysis revealed several gene groups which are related to development of corpus atrophy, some of which were increased also in H. pylori-infected non-atrophic patients. Furthermore, loss of acidic chitinase expression is a promising marker for corpus atrophy.

Gastric intestinal metaplasia revisited: function and regulation of CDX2

Intestinal metaplasia of the stomach is a preneoplastic lesion that appears following Helicobacter pylori infection and confers increased risk for gastric cancer development. However, the molecular networks connecting infection to lesion formation and the cellular origin of this lesion remain largely unknown. A more comprehensive understanding of how intestinal metaplasia arises and is maintained will be a major breakthrough towards developing novel therapeutic interventions. Furthermore, after ascertaining the pivotal role of CDX2 in establishing and maintaining intestinal metaplasia, it becomes important to decipher the upstream molecular pathways leading to its ectopic expression. Here, we review the pathophysiology of intestinal metaplasia in the context of the molecular network involved in its establishment and maintenance, with emphasis on CDX2 function and regulation.

Tests for serum levels of trefoil factor family proteins can improve gastric cancer screening

BACKGROUND & AIMS

Improving methods for early detection of gastric cancer could reduce mortality. Measurements of serum pepsinogen levels have been used for screening in Japan without satisfactory levels of sensitivity or specificity. Trefoil factor family (TFF) proteins (TFF1, TFF2, and TFF3) are small and stable molecules secreted by the mammalian gastrointestinal tract. Foveolar hyperplasia, spasmolytic polypeptide (TFF2)-expressing metaplasia, and intestinal metaplasia are histologic changes observed in patients with atrophic gastritis; they express TFF1, TFF2, and TFF3, respectively. We investigated whether serum levels of TFF can be used as markers for gastric cancer screening.

METHODS

Serum was collected from 183 patients with gastric cancer and 280 healthy individuals without cancer. Serum levels of anti-Helicobacter pylori immunoglobulin G, pepsinogen I, pepsinogen II, TFF1, TFF2, and TFF3 were measured by enzyme-linked immunosorbent assay and associated with gastric cancer.

RESULTS

Using a cutoff of 3.6 ng/mL, the level of TFF3 was significantly increased in serum samples from patients with cancer (odds ratio, 18.1; 95% confidence interval, 11.2-29.2); using this test, patients with cancer were identified with 80.9% sensitivity and 81.0% specificity. The test for TFF3 had a significantly higher odds ratio than that for pepsinogen. A test for the combination of TFF3 and pepsinogen had better results than the test for only pepsinogen.

CONCLUSIONS

Serum levels of TFF3 are a better marker of gastric cancer than pepsinogen; a test for the combined levels of serum pepsinogen and TFF3 could improve gastric cancer screening.

The transcription factor MIST1 is a novel human gastric chief cell marker whose expression is lost in metaplasia, dysplasia, and carcinoma

The lack of reliable molecular markers for normal differentiated epithelial cells limits understanding of human gastric carcinogenesis. Recognized precursor lesions for gastric adenocarcinoma are intestinal metaplasia and spasmolytic polypeptide expressing metaplasia (SPEM), defined here by ectopic CDX2 and TFF2 expression, respectively. In mice, expression of the bHLH transcription factor MIST1, normally restricted to mature chief cells, is down-regulated as chief cells undergo experimentally induced metaplasia. Here, we show MIST1 expression is also a specific marker of human chief cells. SPEM, with and without MIST1, is present in human lesions and, akin to murine data, likely represents transitional (TFF2(+)/MIST1(+) = "hybrid"-SPEM) and established (TFF2(+)/MIST1(-) = SPEM) stages. Co-visualization of MIST1 and CDX2 shows similar progressive loss of MIST1 with a transitional, CDX2(+)/MIST1(-) hybrid-intestinal metaplasia stage. Interinstitutional analysis and comparison of findings in tissue microarrays, resection specimens, and biopsies (n > 400 samples), comprising the entire spectrum of recognized stages of gastric carcinogenesis, confirm MIST1 expression is restricted to the chief cell compartment in normal oxyntic mucosa, rare in established metaplastic lesions, and lost in intraepithelial neoplasia/dysplasia and carcinoma of various types with the exception of rare chief cell carcinoma ( approximately 1%). Our findings implicate MIST1 as a reliable marker of mature, healthy chief cells, and we provide the first evidence that metaplasia in humans arises at least in part from the chief cell lineage.

Epidemiology, pathology and clinical management of multiple gastric cancers: a mini-review

The incidence of multiple gastric cancers (MGCs) has been increasing over the recent decades due to the advance in diagnostic techniques combining with the detailed pathological examinations of surgical resection specimens. Reduction of the surgical extent and trauma under the premise of radical resection improves the quality of life of patients with gastric cancer. However, MGC lesions may have been missed, which can result in adverse consequences. We carried out this systematic review of previous literatures, in order to provide deep insights into epidemiological, pathological and clinical features of MGCs and to establish an efficient way to screen the individuals with high risks. MGCs represent a special type of malignant gastric tumor and possess distinctive features compared with the solitary one. More attention should be paid to both diagnosis and treatment of MGCs. Possibility of overlooking accessory lesions must be kept in mind constantly. For the population at high risk, such as the elderly with differentiated type, strict perioperative tissue examinations and follow-up are essential.

Current understanding of SPEM and its standing in the preneoplastic process

Gastric cancer is the second leading cause of cancer-related death worldwide, but the details of gastric carcinogenesis remain unclear. In humans, two preneoplastic metaplasias are associated with the precancerous stomach: intestinal metaplasia and spasmolytic polypeptide-expressing metaplasia (SPEM). While mouse models of Helicobacter sp. infection have not shown intestinal metaplasia, a number of mouse models lead to the evolution of SPEM. In this review, we summarize increasing data that indicates that SPEM arises in the setting of parietal cell loss, either following acute druginduced oxyntic atrophy or in chronic oxyntic atrophy associated with H. felis infection. Importantly, recent investigations support the origin of SPEM through transdifferentiation from mature chief cells following parietal cell loss. Novel biomarkers of SPEM, such as HE4, hold promise as specific markers of the metaplastic process distinct from normal gastric lineages. Staining with HE4 in humans and other studies in gerbils suggest that SPEM arises initially in the human stomach following parietal cell loss and then further evolves into intestinal metaplasia, likely in association with chronic inflammation. Further studies are needed to broaden our knowledge of metaplasia and early cancer-specific biomarkers that could give insights into both lineage derivation and preneoplasia detection.

Oxyntic atrophy, metaplasia, and gastric cancer

Gastric carcinogenesis involves the loss of parietal cells (oxyntic atrophy) and subsequent replacement of the normal gastric lineages with metaplastic cells. In humans, two metaplastic lineages develop as sequelae of chronic Helicobacter pylori infection: intestinal metaplasia and spasmolytic polypeptide-expressing metaplasia (SPEM). Mouse models of both chronic Helicobacter infection and acute pharmacological oxyntic atrophy have led to the discovery that SPEM arises from transdifferentiation of mature chief cells. The presence of inflammation promotes the expansion of SPEM in mice. Furthermore, studies in Mongolian gerbils as well as increasing evidence from human studies indicate that SPEM likely represents a precursor for the development of intestinal metaplasia. These findings suggest that loss of parietal cells, augmented by chronic inflammation, leads to a cascade of metaplastic events. Identification of specific biomarkers for SPEM and intestinal metaplasia hold promise for providing both early detection of preneoplasia and information on prognostic outcome following curative resection.

Alterations of gastric homeoprotein expression in Helicobacter pylori infection, incisural antralisation, and intestinal metaplasia

PURPOSE

This study was to determine whether gastric expression of homeoproteins is altered in Helicobacter pylori infection, incisural antralisation, and intestinal metaplasia (IM).

METHODS

Gastric biopsy specimens were taken from 98 patients with non-ulcer dyspepsia for the detection of H. pylori infection; histological examinations; immunohistochemical staining of CDX2, PDX1, PAX6, and NKX6.1.

RESULTS

Of the patients, 38 were positive for H. pylori infection, 44 had antral-type mucosa at the incisura, and 22 had IM in the stomach. At the incisura, the expression of PDX1, NKX6.1, and PAX6 in cytoplasm compartment was down-regulated in antral-type mucosa compared with that in the transitional- or body-type mucosa (all P<0.01). The expression of PDX1, PAX6, and NKX6.1 in cytoplasm at the incisura was down-regulated in H. pylori-infected patients compared with that in those without H. pylori infection (all P<0.01). CDX2 expression in whole stomach was up-regulated, but PDX1 expression at the incisura was down-regulated in patients with IM compared with that in those without IM (all P<0.01).

CONCLUSIONS

Gastric expression of PDX1, PAX 6, and NKX6.1 is down-regulated in H. pylori infection and incisural antralisation. CDX2 is up-regulated but PDX1 is down-regulated in the presence of IM.

Effect of antrectomy in hypergastrinaemic female Japanese cotton rats

OBJECTIVE

Female Japanese cotton rats become hypoacidic and hypergastrinaemic from age 2 months and later develop gastric carcinomas in the oxyntic mucosa. Previous studies have demonstrated that carcinogenesis can be halted by a gastrin receptor antagonist and that carcinomas can be induced by a histamine-2 receptor antagonist or partial corpectomy, both of which induce hypergastrinaemia. The aim of the present study was to examine the effect of antrectomy in female cotton rats.

MATERIAL AND METHODS

The animals were either antrectomized (Group 1) or sham-operated (Group 2) 2 months after detection of hypergastrinaemia and terminated 4 months after operation. A third group was antrectomized at age 2 months while still normo-acidic (Group 3) and terminated 6 months after operation.

RESULTS

Antrectomy after 2 months of hypergastrinaemia prevented the development of carcinoma compared with in sham-operated animals, whereas some of the animals that were antrectomized at 2 months of age also developed carcinomas. In Groups 1 and 2 as well as in animals developing carcinomas in Group 3, there was marked hyperplasia of neuroendocrine cells in the oxyntic mucosa expressing chromogranin A, vesicular monoamine transporter (VMAT)-2, ghrelin and somatostatin. Gastrin-positive cells were found adjacent to neoplastic areas in the oxyntic mucosa.

CONCLUSIONS

The removal of antral gastrin by antrectomy halts carcinogenesis in cotton rats, but other mechanisms may also play a role.

Optimal approach to obtaining mucosal biopsies for assessment of inflammatory disorders of the gastrointestinal tract

Endoscopic evaluation and mucosal biopsy analysis have assumed important roles in the clinical management of patients with symptoms related to the gastrointestinal tract. Several common inflammatory diseases, including eosinophilic esophagitis, Barrett's esophagus, Helicobacter pylori infection, celiac disease, lymphocytic colitis, collagenous colitis, and inflammatory bowel disease, may display a patchy or discontinuous distribution and, thus, multiple mucosal samples may be required to obtain diagnostic tissue in some cases. Not surprisingly, clinicians and pathologists are increasingly challenged to determine the optimum number of procedures and tissue samples necessary to detect, or exclude, the presence of inflammatory disorders of the gastrointestinal tract. Unfortunately, clinical practice varies widely with respect to tissue sample procurement in the evaluation of these disorders, particularly when the endoscopic appearance of the gastrointestinal mucosa is normal or shows only minimal changes. Guidelines concerning the appropriate number of tissue samples are well established for some diseases, such as Barrett's esophagus and chronic gastritis, but are not clear in other instances. The purpose of this review is to discuss the available literature pertaining to appropriate endoscopic sampling in the assessment of medical diseases of the gastrointestinal tract, and to develop recommendations regarding the clinical evaluation of common gastrointestinal disorders.

Helicobacter pylori, inflammation, oxidative damage and gastric cancer: a morphological, biological and molecular pathway

Gastric carcinogenesis is a complex, multistep and multifactorial event, characterized by progressive cyto-histological dedifferentiation, in which the role of Helicobacter pylori infection has been established. Among the pathways relevant to gastric carcinogenesis and correlated with H. pylori infection, it has been demonstrated that the production of reactive oxygen species, with damage to the DNA, may be quite important. Oxidative damage, alone and/or in combination with exogenous and endogenous factors, induces several molecular changes. The assumption is that, in precancerous lesions, these molecular changes belong to the same biological spectrum as their invasive counterpart. The molecular profile of these preneoplastic lesions is heterogeneous, however, and there are still no molecular markers enabling the distinction between atypical hyperplastic lesions and low-grade noninvasive neoplasia (NiN) or between high-grade NiN and early invasive neoplasia. Indeed, within the spectrum of morphological changes characterizing this multistep evolution, dysplasia (NiN) is the lesion coming closest to the development of invasive adenocarcinoma. Several of the genetic and epigenetic alterations reported in gastric precancerous lesions affect DNA repair system genes, tumor suppressor genes, oncogenes, cell cycle regulators, growth factors, and adhesion molecules. Although we await reliable molecular markers, it is best to monitor patients harboring NiN closely with endoscopy and extensive bioptic sampling, and to eradicate any H. pylori to prevent the accumulation of oxidative DNA damage and its consequent progression. The growing body of evidence of the regression of precancerous changes and the high prevalence of superficial gastric carcinoma demonstrated in long-term follow-up studies on NiN make this approach mandatory.

Association of Helicobacter pylori infection with chronic atrophic gastritis: Meta-analyses according to type of disease definition

Helicobacter pylori is a major risk factor for chronic atrophic gastritis (CAG). A large variety of definitions of CAG have been used in epidemiologic studies in the past. The aim of this work was to systematically review and summarize estimates of the association between H. pylori infection and CAG according to the various definitions of CAG. Articles on the association between H. pylori infection and CAG published until July 2007 were identified. Separate meta-analyses were carried out for studies defining CAG based on gastroscopy with biopsy, serum pepsinogen I (PG I) only, the pepsinogen I/pepsinogen II ratio (PG I/PG II ratio) only, or a combination of PG I and the PG I/PG II ratio. Numbers of identified studies and summary odds ratios (OR) (95% confidence intervals) were as follows: gastroscopy with biopsy: n = 34, OR = 6.4 (4.0-10.1); PG I only: n = 13, OR = 0.9 (0.7-1.2); PG I/PG II ratio: n = 8, OR = 7.2 (3.1-16.8); combination of PG I and the PG I/PG II ratio: n = 20, OR = 5.7 (4.4-7.5). Studies with CAG definitions based on gastroscopy with biopsy or the PG I/PG II ratio (alone or in combination with PG I) yield similarly strong associations of H. pylori with CAG. The association is missed entirely in studies where CAG is defined by PG I only.

External validation of a classification for methylene blue magnification chromoendoscopy in premalignant gastric lesions

BACKGROUND

Conventional endoscopy has low sensitivity, specificity, and interobserver agreement for the diagnosis of gastric atrophy, intestinal metaplasia, and dysplasia. Magnification chromoendoscopy (ME) may optimize the evaluation of premalignant gastric lesions.

OBJECTIVE AND DESIGN

As part of a multicenter trial, we aimed at validating a previously proposed classification for gastric methylene blue ME at a different center. SETTING, PATIENTS, AND INTERVENTIONS: A sample of patients (n = 42) with previously diagnosed chronic atrophic gastritis with or without intestinal metaplasia underwent ME (Pentax EG-3430Z) with 1% methylene blue by 2 endoscopists.

MAIN OUTCOME MEASUREMENTS

A simplified version of a previously published ME classification (group I, group II [further divided into subgroups IIE and IIF], and group III) was used for macroscopic lesions (n = 203) with Sydney-Houston and Vienna classifications being used for histologic analysis (n = 479 biopsy specimens).

RESULTS AND LIMITATIONS

Excellent reproducibility (wK = 0.92 [95% CI, 0.88-0.96]) was observed for classification in groups and substantial reproducibility (wK = 0.78 [95% CI, 0.72-0.84]) was found for classification in subgroups. Global validity was 82% (range 78%-86%), showing no false negatives (sensitivity of 100% [1/1 biopsy]) and a very low rate of false positives (specificity 99% [297/299 biopsies]) for dysplasia detection.

CONCLUSIONS

This classification for methylene blue ME was highly reproducible and valid for the diagnosis of premalignant gastric lesions when used in a center different from that involved in its conception. Despite requiring an unconventional endoscope and a longer procedure, these results could reinforce ME as a valuable technique in the surveillance of patients at risk for gastric cancer.

Systematic review of the prevalence of gastric intestinal metaplasia and its area-level association with smoking

OBJECTIVES

We aimed to show an area-level association between the frequency of intestinal metaplasia (IM) in Helicobacter pylori-infected patients and tobacco consumption.

METHODS

We systematically reviewed the literature to retrieve data on the prevalence of IM in different countries and performed an ecological analysis to quantify the association between the prevalence of IM among infected subjects and smoking, using data on national tobacco availability. Articles evaluating IM in the general population or in dyspeptic patients were identified by a MEDLINE search. We selected one study per country, giving preference to those for which the study design/populations evaluated provided the highest external validity and inter-study comparability of methodology.

RESULTS

This systematic review of published data retrieved information for 29 countries from 5 continents depicting a wide variation in the prevalence of IM among H. pylori-infected subjects in different regions, ranging from 3% in Argentina to 55% in New Zealand. In countries exhibiting a simultaneously high prevalence of infection and low incidence of gastric cancer, IM was also relatively infrequent (Thailand, 6%; India, 8.2%; Nigeria, 11.1%; Gambia, 11.8%; Saudi Arabia, 15.5%; Iran, 15.6%; Egypt, 24.4%). A significant correlation was observed between IM prevalence in infected subjects and tobacco availability (r = 0.45; p = 0.02).

CONCLUSIONS

Our results show that the concept of the African and Asian "enigmas" may be extended to precancerous lesions. Tobacco availability was positively associated with the prevalence of IM among H. pylori-infected subjects at an area level.

Prevalence and distribution of gastric intestinal metaplasia and its subtypes

BACKGROUND AND STUDY AIMS

Intestinal metaplasia, especially type III intestinal metaplasia is considered to be a precursor of gastric cancer and because of this it is suggested that these patients should be followed up by gastroscopy. Our aim was to find out the prevalence of intestinal metaplasia and its subtypes, the appearance of intestinal metaplasia in different parts of the stomach, and the correlation of intestinal metaplasia with other histological and endoscopic findings.

PATIENTS AND METHODS

A total of 505 consecutive patients, with a mean age+/-S.D. of 54+/-16 years, had two biopsies taken from the antrum, two from the corpus, and, in 272 cases, two from the angulus of the stomach during routine upper gastrointestinal endoscopy. Histological specimens were examined according to the updated Sydney system and the ones with incomplete intestinal metaplasia were further stained for sulphomucin visualisation to divide these into types II and III.

RESULTS

The overall prevalence of intestinal metaplasia was 19%. The prevalence of type III intestinal metaplasia was 2.8%, type II intestinal metaplasia was 4.4%, and complete intestinal metaplasia was 11%. Intestinal metaplasia was found most frequently in the antrum and also in the angulus. There was no type III intestinal metaplasia in the corpus. Intestinal metaplasia was found more frequently in patients with atrophic gastritis than in other patients (p < 0.01). The patients with type III intestinal metaplasia were older than the patients without intestinal metaplasia (mean age of 73 versus 51 years). None of the patients with a totally normal appearing stomach in upper gastrointestinal endoscopy had type II or type III intestinal metaplasia.

CONCLUSION

The relatively high overall prevalence of intestinal metaplasia was found in patients referred for gastroscopy in a region of low prevalence of Helicobacter pylori infection and low incidence of gastric cancer. Intestinal metaplasia was most often found in the antrum and angulus. Type III intestinal metaplasia was more prevalent in older patients and intestinal metaplasia was more frequently found in patients with atrophic gastritis. Normal appearing endoscopic finding seems to exclude type II and III intestinal metaplasia.

An evaluation of a serologic test with a current infection marker of Helicobacter pylori before and after eradication therapy in Chinese

BACKGROUND AND AIMS

Development of an accurate and less cumbersome noninvasive method to detect current Helicobacter pylori infection is essential in clinic. The aim of this study was to evaluate the performance of the CIM test, also known as the Assure H. pylori Rapid Test (Genelabs Diagnostics Pty. Ltd., Singapore), for the diagnosis of current H. pylori infection before and after eradication therapy in Chinese population.

METHODS

A total of 452 eligible people were recruited for this study in Jiangsu Province, China. Each individual underwent a 13C urea breath test (13C-UBT). For the evaluation of CIM test after eradication, 115 H. pylori-positive outpatients were treated with 1-week triple therapy. One month after the end of therapy, the patients underwent 13C-UBT again, and the CIM-test was performed 1, 3, and 6 months after the end of therapy. Its performance (sensitivity, specificity, positive and negative predictive values, and accuracy) were determined using the 13C-UBT as a gold standard for H. pylori diagnosis.

RESULTS

H. pylori was detected in 221 (65.6%) of the 337 people by 13C-UBT. The sensitivity, specificity, positive and negative predictive values, and accuracy of the CIM test were 93.2%, 90.5%, 94.9%, 87.5%, and 92.3%, respectively, using 13C-UBT as a gold standard. One month after eradication therapy, the sensitivity, specificity of CIM test were only 50% and 66.7%, 66.7% and 84.6% 3-month after eradication therapy and the sensitivity, specificity increased to 85.7% and 96.9%, respectively, when CIM test was used 6 months after the end of anti-H. pylori therapy.

CONCLUSIONS

The CIM test is a simple, rapid, accurate, cheap, and near-people test. It may be satisfactory for detecting H. pylori infection in cases without eradication therapy, but it could not differentiate the past or current infection correctly within 6 months after anti-H. pylori therapy.

Using serum pepsinogens wisely in a clinical practice

Serum pepsinogen (PG) has been used as biomarkers of gastric inflammation and mucosal status, including atrophic change, before the discovery of Helicobacter pylori (H. pylori). Serum pepsinogen I (PG I) and pepsinogen II (PG II) levels are known to increase in the presence of H. pylori-related nonatrophic chronic gastritis. The measurement of serum PG provides much information on the presence of intestinal metaplasia as well as atrophic gastritis. The eradication of H. pylori provokes a significant change in serum PG values: it reduces both PG I and PG II and elevates the PG I to PG II ratio. Recently, the serum PG test method has been the first screening step in Japan, as well as photofluorography. Serum PG tests are used to screen for high risk subjects with atrophic gastritis, rather than as a test for cancer itself. Unlike photofluorography or endoscopy, serum PG screening can identify non-ulcerated differentiated asymptomatic cancer, irrespective of the size and location of the lesion. Most cases detected by the PG method are asymptomatic early gastric cancers and are limited to the mucosa, which are particularly well suited for endoscopic treatment. The PG method can contribute greatly to the patients' quality of life.

Helicobacter pylori eradication for gastric cancer prevention

Gastric cancer is the second most common fatal malignancy in the world. Its incidence is high in East Asia. Helicobacter pylori infection is an important factor in the pathogenesis of gastric cancer. Epidemiological studies have established a strong causal relationship between H. pylori infection and gastric cancer. H. pylori eradication is therefore likely to be one of the most promising approaches to gastric cancer prevention. Animal studies have shown that eradication of H. pylori infection, especially at the early stage, is effective in preventing H. pylori-related gastric carcinogenesis. However, the available data from human studies show that H. pylori eradication does not completely prevent gastric cancer and that it might be useful only in patients without atrophic gastritis or intestinal metaplasia at baseline. Longer follow-up and additional studies are needed to clarify this issue.

Atrophic Autoimmune Pangastritis: A Distinctive Form of Antral and Fundic Gastritis Associated With Systemic Autoimmune Disease

The 2 major recognized forms of atrophic gastritis are autoimmune and environmental atrophic gastritis. These differ in their topographical distribution in the stomach, histologic features, and etiology. Autoimmune atrophic gastritis results from immune-mediated destruction of specialized oxyntic glands, is restricted to the body and fundus, and shows characteristic neuroendocrine hyperplasia. Environmental atrophic gastritis is associated with long-standing Helicobacter pylori infection and preferentially involves antrum and transition zone mucosa. In this study, we describe a distinctive form of atrophic gastritis that differs markedly from both of these classic variants. This gastritis is characterized by: (1) intense mucosal inflammatory infiltrates, persisting even into the phase of severe glandular atrophy, (2) pangastric distribution with diffuse involvement of both body and antrum, (3) lack of association with H. pylori, and (4) lack of neuroendocrine hyperplasia. The 8 patients presented ranged from 1 to 75 years and showed a slight female predominance (5F:3M). All had systemic autoimmune and/or connective tissue diseases including autoimmune enterocolitis (4 cases), systemic lupus erythematosus, refractory sprue, autoimmune hemolytic anemia, and disabling fibromyalgia. Positive serum autoimmune markers were documented in 7 of 8 (87%) patients, but serologies for antiparietal cell and anti-intrinsic factor antibodies were undertaken in only 1 patient each and were negative. We propose that the distinctive histology of this form of atrophic pangastritis and its association with systemic autoimmune disease suggests an autoimmune process directed against multiple cell lineages in the stomach. The development of multifocal low-grade dysplasia in 1 patient, a 19-year-old woman, suggests that this condition might have neoplastic potential.

Regional differences in the recovery of gastric acid secretion after Helicobacter pylori eradication: evaluations with Congo red chromoendoscopy

BACKGROUND

Gastric-acid secretion is reduced in Helicobacter pylori-positive fundic atrophic gastritis, but it is restored by the eradication. However, changes in the distribution of acid-secreting mucosa after the eradication remain unknown. Congo red chromoendoscopy is capable of visualizing the acid-secreting fundic mucosa.

OBJECTIVE

To evaluate the effect of H pylori eradication on the distribution of acid-secreting mucosa in the fundus by using Congo red chromoendoscopy.

DESIGN

An assessment of the distribution of acid-secreting mucosa by the visualized images of Congo red chromoendoscopy and a histologic evaluation of biopsy specimens were performed before and 1 and 7 months after the eradication. The areas of the acid-secreting mucosa in the lesser and greater curvatures of the fundus were evaluated semiquantitatively.

PATIENTS

Thirty-seven patients positive for H pylori and with fundic atrophic gastritis.

RESULTS

The area of the acid-secreting mucosa increased in 27 cases (73%) by 1 month after eradication, and in 32 cases (86%) by 7 months. This expansion of the acid-secreting mucosa coincided with the improvement of inflammatory changes rather than with that of the mucosal atrophy and was more prominent on the greater curvature than on the lesser curvature.

CONCLUSIONS

The acid-secreting mucosa in the fundus expanded in most cases with fundic atrophic gastritis after H pylori eradication, which could be responsible for the increase in acid secretion after the treatment. Regional differences in the recovery of local acid secretion may be associated with site-specific susceptibility to the development of gastric cancer after successful eradication.

Significance of 24-h intragastric pH monitoring and serum concentration of gastrin in chronic atrophic gastritis

AIM: To evaluate the clinical significance of 24-h intragastric pH monitoring and the serum concentration of gastrin in patients with chronic atrophic gastritis (CAG).

METHODS: A total of 126 patients with chronic gastritis, confirmed by endoscopy combined with pathological examination, were recruited in this study. Based on histological results, the patients were devided into 4 groups: non-atrophic gastritis, mild, moderate and severe CAG group, respectively. The 24-h intragastric pH value was monitored using mobile pH measuring apparatus. The serum concentration of gastrin was detected by enzyme-linked immunosorbent assay (ELISA), and H. pylori infection was determined by rapid urease test and ¹⁴C urea breath test.

RESULTS: H. pylori infection was assured in 73 patients, of which 52 cases were diagnosed with CAG. The rates of H. pylori infection showed no difference between the two groups. The intragastric 24-h median pH value, mean pH value, and nightly median pH value were significant higher in patients with severe CAG than those in the others (P < 0.05). The content of gastrin was the highest in patients without CAG, significantly higher than that in the others (59.21 ± 17.36, 54.67 ± 15.84, 50.78 ± 13.13 vs 74.24 ± 19.52 nmol/L, P < 0.05).

CONCLUSION: Besides endoscopy and biopsy, the combination of intragastric pH monitoring and serum gastrin detection is helpful in the improvement of CAG diagnosis, so as to guide clinical treatment.

Local expressions of TGF-beta1, TGF-beta1RI, CTGF, and Smad-7 in Helicobacter pylori-associated gastritis

OBJECTIVE

Transforming growth-factor (TGF)-beta1 and Smad-7 play important roles in Helicobacter pylori (H. pylori)-associated gastritis. Connective tissue growth factor (CTGF) can facilitate the TGF-beta/Smad signaling by switching off Smad-7. The purpose of this study was to examine the in situ expressions of these cytokines in the gastric antrum with or without H. pylori infection.

MATERIAL AND METHODS

Antral specimens from 166 patients (96 M, 70 F, median age 52 years, range 26 to 76 years) were used in this study. H. pylori infection status was determined by histological examination and (UBT) [13C]-urea breath test. Degrees of severity and activity of chronic gastritis were scored for all specimens. Immunohistochemistry was used to demonstrate local expressions of TGF-beta1, TGF-beta1 type 1 receptor (TGF-beta1RI), Smad-7, and CTGF in the gastric antrum.

RESULTS

The results demonstrated that mononuclear cells (MNCs) in lamina propria were the major source of these cytokines. The number of MNCs stained with TGF-beta1, TGF-beta1RI, CTGF, and Smad-7 was significantly higher in H. pylori-positive patients than in H. pylori-negative patients. Furthermore, there was a positive correlation between these cytokine-producing MNCs and the severity of chronic gastritis.

CONCLUSIONS

H. pylori infection is associated with increased expression of TGF-beta1, TGF-beta1RI, Smad-7, and CTGF in the gastric antrum. Our results also suggest that the feed-back loop consisting of TGF-beta1, Smad-7, and CTGF may play an important role in the pathogenesis of H. pylori-associated gastritis.