My approach to reporting a gastric biopsy

Elevated gaseous luminal nitric oxide and circulating IL-8 as features of Helicobacter pylori-induced gastric inflammation

BACKGROUND

Gastric nitric oxide (NO) production in response to Helicobacter pylori via inducible nitric oxide synthase (iNOS) is suggested as a biomarker of inflammation and cytotoxicity. The aim of this study was to investigate relationships between gastric [NO], immunological biomarkers and histopathology.

MATERIALS AND METHODS

Esophagogastroduodenoscopy was done in 96 dyspepsia patients. Luminal [NO] was measured by chemiluminescence. Biopsies were taken from gastric antrum and corpus for culture and histopathology. H. pylori IgG was detected by immunoblot assay. Biobanked plasma from 76 dyspepsia patients (11 H. pylori positives) was analyzed for 39 cytokines by multiplexed ELISA.

RESULTS

H. pylori-positive patients had higher [NO] (336 ± 26 ppb, mean ± 95% CI, n = 77) than H. pylori-negative patients (128 ± 47 ppb, n = 19) (P < 0.0001). Histopathological changes were found in 99% of H. pylori-positive and 37% of H. pylori-negative patients. Histopathological concordance was 78-100% between corpus and antrum. Correlations were found between gastric [NO] and severity of acute, but not chronic, inflammation. Plasma IL-8 (increased in H. pylori positives) had greatest difference between positive and negative groups, with eotaxin, MIP-1β, MCP-4, VEGF-A, and VEGF-C also higher (P < 0.004 to P < 0.032). Diagnostic odds ratios using 75% cut-off concentration were 7.53 for IL-8, 1.15 for CRP, and 2.88 for gastric NO.

CONCLUSIONS

Of the parameters tested, increased gastric [NO] and circulating IL-8 align most consistently and selectively in H. pylori-infected patients. Severity of mucosal inflammatory changes is proportional to luminal [NO], which might be tied to IL-8 production. It is proposed that IL-8 be further investigated as a blood biomarker of treatment outcomes.

Distinct patterns of naive, activated and memory T and B cells in blood of patients with ulcerative colitis or Crohn's disease

Both major subcategories of inflammatory bowel disease (IBD), ulcerative colitis and Crohn’s disease are characterized by infiltration of the gut wall by inflammatory effector cells and elevated biomarkers of inflammation in blood and feces. We investigated the phenotypes of circulating lymphocytes in the two types of IBD in treatment‐naive pediatric patients by analysis of blood samples by flow cytometry. Multivariate analysis was used to compare the phenotypes of the blood lymphocytes of children with ulcerative colitis (n = 17) or Crohn’s disease (n = 8) and non‐IBD control children with gastrointestinal symptoms, but no signs of gut inflammation (n = 23). The two IBD subcategories could be distinguished based on the results from the flow cytometry panel. Ulcerative colitis was characterized by activated T cells, primarily in the CD8⁺ population, as judged by increased expression of human leukocyte antigen D‐related (HLA‐DR) and the β1‐integrins [very late antigen (VLA)] and a reduced proportion of naive (CD62L⁺) T cells, compared with the non‐IBD controls. This T cell activation correlated positively with fecal and blood biomarkers of inflammation. In contrast, the patients with Crohn’s disease were characterized by a reduced proportion of B cells of the memory CD27⁺ phenotype compared to the non‐IBD controls. Both the patients with ulcerative colitis and those with Crohn’s disease showed increased percentages of CD23⁺ B cells, which we demonstrate here as being naive B cells. The results support the notion that the two major forms of IBD may partially have different pathogenic mechanisms.

Canine Gastric Pathology: A Review

Gastric disorders are common in dogs and are a major reason for veterinary consultation. In human medicine, the classification of gastric diseases based on histological features, genotypes and molecular phenotypes helps to better understand the characteristics of each subtype, and to improve early diagnosis, prevention and treatment. Canine gastric lesions often show strong histological similarities to their human counterparts. However, such conditions in the canine stomach are poorly studied and their cellular and molecular features are largely unknown. This article reviews the histopathological classification of inflammatory and neoplastic lesions of the canine stomach and provides an update on the application of molecular techniques within the field of canine gastric pathology. The canine disorders are compared with current knowledge of the equivalent human diseases.

The Natural Antimicrobial Enzyme Lysozyme is Up-Regulated in Gastrointestinal Inflammatory Conditions

The cells that line the mucosa of the human gastrointestinal tract (GI, that is, oral cavity, oesophagus, stomach, small intestine, large intestine, and rectum) are constantly challenged by adverse micro-environmental factors, such as different pH, enzymes, and bacterial flora. With exception of the oral cavity, these microenvironments also contain remnant cocktails of secreted enzymes and bacteria from upper organs along the tract. The density of the GI bacteria varies, from 103/mL near the gastric outlet, to 1010/mL at the ileocecal valve, to 1011 to 1012/mL in the colon. The total microbial population (ca. 1014) exceeds the total number of cells in the tract. It is, therefore, remarkable that despite the prima facie inauspicious mixture of harmful secretions and bacteria, the normal GI mucosa retains a healthy state of cell renewal. To counteract the hostile microenvironment, the GI epithelia react by speeding cell exfoliation (the GI mucosa has a turnover time of two to three days), by increasing peristalsis, by eliminating bacteria through secretion of plasma cell-immunoglobulins and by increasing production of natural antibacterial compounds, such as defensin-5 and lysozyme. Only recently, lysozyme was found up-regulated in Barrett's oesophagitis, chronic gastritis, gluten-induced atrophic duodenitis (coeliac disease), collagenous colitis, lymphocytic colitis, and Crohn's colitis. This up-regulation is a response directed to the special types of bacteria recently detected in these diseases. The aim of lysozyme up-regulation is to protect individual mucosal segments to chronic inflammation. The molecular mechanisms connected to the crosstalk between the intraluminal bacterial flora and the production of lysozyme released by the GI mucosae, are discussed. Bacterial resistance continues to exhaust our supply of commercial antibiotics. The potential use of lysozyme to treat infectious diseases is receiving much attention.

Paucity of synaptophysin-expressing cells in Barrett's mucosa

AIMS

To assess synaptophysin expression in columnar-lined oesophageal mucosa showing either goblet cells, known as intestinal metaplasia, or with accompanying oxyntic glands or pyloric glands.

METHODS AND RESULTS

Of 159 biopsies, 53 were oesophageal (19 had intestinal metaplasia, 13 oxyntic glands, and 21 pyloric glands), 77 gastric (12 had goblet cells and 27 no goblet cells) and 29 duodenal. Synaptophysin-positive goblet cells were found in all biopsies from the normal duodenum, in 53% of the oesophageal biopsies showing intestinal metaplasia, but only in 8% of gastric biopsies showing intestinal metaplasia. Synaptophysin-positive Paneth cells occurred in all duodenal biopsies, and in nine of the gastric biopsies showing intestinal metaplasia, but in only one of the oesophageal biopsies showing intestinal metaplasia. A continuous synaptophysin-positive neck cell zone was found in all biopsies from the normal antrum, but in none of the oesophageal biopsies with pyloric glands or with chronic antritis.

CONCLUSIONS

The paucity or absence of synaptophysin-positive cells in all three phenotypes of Barrett's mucosa might mirror a sequela of chronic inflammation caused by the particular pathogenic bacteria present in the immediate oesophageal microenvironment.

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.

Plugs clog the glandular outlets in fundic gland polyps

A systematic histologic analysis of 62 gastric fundic gland polyps (FGP) was carried out. All FGP (100%) showed foveolar cells with hypertrophic cytoplasm. In 95% of the FGP, parietal cells ballooned into the lumen and in 93%, exfoliated anucleated structures with eosinophilic granules were found. Plugs of anucleated structures with eosinophilic granules, most likely derived from exfoliated parietal cells, were found to clog the outlets of the glands in 86% of the FGP. None of the 30 control gastric biopsies without FGP had similar cellular aberrations. FGP seems to evolve by cellular aberrations affecting parietal cells. This is not surprising considering that genetic mutations are recorded in FGP with a common APC/b-catenin pathway in both FAP and sporadic cases. The genetic mutations in FGP might alter the biological behavior of the parietal cells, leading to increased exfoliation with clogging of the outlets of the glands. Thus, the blocking of the glandular outflow by plugs of anucleated structures with eosinophilic granules is the most likely cause for the cystic accumulation of "normal" glandular secretions.

Increased lysozyme expression in gastric biopsies with intestinal metaplasia and pseudopyloric metaplasia

Lysozyme is an innate enzyme with potent non-immunological antibacterial properties in the upper intestinal tract. Lysozyme expression (ly-ex) was investigated in 80 consecutive sets of gastric biopsies having normal gastric mucosa (n=20), chronic gastritis (n=20), gastric intestinal metaplasia (IM, n=20), and pseudopyloric metaplasia (PpM, n=20). In biopsies with normal mucosa and with chronic gastritis, the foveolar epithelium and the mucus neck cells of the fundic mucosa as well as the antropyloric glands had moderate (++) to marked (+++) ly-ex whereas the fundic glands proper did not express lysozyme. In IM the goblet and the Paneth cells showed marked (+++) ly-ex. PpM, developing in patients with autoimmune (corpus) gastritis, had moderate ly-ex (++), thus contrasting with the negative ly-ex in the normal or inflamed fundic mucosa. The Helicobacter pylori did not proliferate in areas with IM or with PpM. The lysozyme production in IM and in PpM might be upregulated to eradicate ingested, proliferating bacteria in acid-deficient stomachs.

Gastritis and gastric atrophy

PURPOSE OF REVIEW

The majority of problems in interpreting gastritis remain Helicobacter related, but their nature has changed. The present review covers gastritis historically through cancer risk staging systems.

RECENT FINDINGS

Key points to remember are: Helicobacter is associated with several forms of gastritis; in the present review, I am focusing on the two ends of the disease, 'Helicobacter pylori infection', that starts with antral predominant gastritis but can continue to oxyntic predominant disease with atrophy; the role Helicobacter pylori plays in autoimmune gastritis with pernicious anemia remains unresolved; gastritis staging systems for cancer risk, namely Baylor and Operative Link on Gastritis Assessment, are currently available.

SUMMARY

As most gastric carcinomas arise on a background of atrophic gastritis, and the risk increases with the extent of atrophy, an index of atrophy location and extent could be useful in predicting patients at greatest risk for carcinoma. It is now possible to stage patients for cancer risk. Nonetheless, in a field such as gastritis in which many issues remain unresolved, a classification or staging system that is more descriptive will likely prove more useful.

Antralization of the gastric mucosa of the incisura angularis and its gastrin expression

The frequency of antrum-type mucosa and gastrin expression in gastric biopsies from the incisura angularis was assessed in 60 consecutive patients having gastrointestinal symptoms. Following the recommendations from the updated Sydney System for the classification and grading of gastritis, two biopsies were taken from the antrum, one from the incisura and two from the corpus. Sections were stained with H&E, Giemsa and for gastrin. Gastrin-positive cells were semi-quantified as: 0 (none), </= 9, 10- 49 cells and >/=50 gastrin-labelled cells/40x field. Antrum-type mucosa at the incisura (called antralization) occurred in 30% of the biopsies without inflammation, but in 69% of those with H. pylori-induced gastritis, and in 64% of those with autoimmune gastritis. At the incisura, gastrin-labelled cells (>/=10) were found in 62% (18/29) of biopsies showing antralization, but in only 20% (3/15) of those having transitional-type mucosa (p<0.05) and in none of the 16 biopsies having fundic-type mucosa. The similarity in gastrin expression between the mucosa of the gastric antrum and the antral-type mucosa at the incisura substantiates the notion that antralization is a metaplastic transformation. The significantly higher frequency of antral-type mucosa at the incisura in patients with gastritis than in those without gastritis strongly suggests that chronic inflammation per se triggers antralization of the incisura, irrespective of the presence or absence of H. pylori infection.

The columnar-lined mucosa at the gastroesophageal junction in non-human primates

Despite that anatomists consider the cardia as a portion of the stomach, there is disagreement in the literature over whether the cardia mucosa, described as columnar-lined with mucus-producing glands (CLMMG) with or without occasional interspersed oxyntic cells, is part of the stomach, part of the esophagus or a distinct entity. For some authors this mucosa phenotype is a metaplastic glandular change of the distal esophagus caused by protracted gastro-esophageal reflux (GER). In this survey, the presence of CLMMG mucosa was searched for at the esophagus-gastric junction in 50 non-human primates (NHP). The length of the CLMMG (between the squamous epithelium of the esophagus and the first oxyntic fundic gastric gland) was assessed by the aid of an ocular microscale. In all three foetuses, all four stillborn baboons and one 4 day old baboon, the columnar-lined mucosa showed depressions that corresponded to early epithelial pits without glands. In the remaining 45 post-natal NHP, the length of the CLMMG mucosa varied from 0.8 mm to 25.2 mm, and the CLMMG mucosa had replaced the distal esophageal squamous epithelium. The size was neither influenced by the post-natal age nor by the gender of the animals. In NHP, regurgitation with rumination is a natural physiological process leading to GER. The present investigation substantiates the notion that the columnar-lined mucosa with mucus-producing glands is a post-natal developmental process in NHP. These animals seem to offer an excellent spontaneous model to study the series of histological events that take place in the distal esophagus of NHP, most likely under the influence of protracted GER.