Radial distribution of dilated intercellular spaces of the esophageal squamous epithelium in patients with reflux disease exhibiting discrete endoscopic lesions

Introduction: Dilatation of intercellular spaces of the esophageal squamous epithelium has been suggested as a marker of early acid reflux-induced damage. This change is a potentially useful addition to histomorphological changes that represent so called minimal endoscopic lesions. We have assessed dilatation of intercellular spaces with regard to: (1) interobserver variability, and (2) whether the incidence of this varies between 'red streaks' and the adjacent normal looking squamous epithelium. Methods: Esophageal biopsies from 44 patients with chronic gastro-esophageal reflux (GERD) were evaluated. At endoscopy, these patients had one or more red streaks on the tops of the mucosal folds in the distal esophagus. Biopsies were taken from the red streaks and from the normal-appearing mucosa 1 cm lateral to the red streaks. Biopsies were assessed in a blinded fashion by two independent pathologists (MV & RF). Criteria for assessing intercellular space dilatation were evaluated and agreed on prior to the study. Results: Good interobserver agreement was recorded (kappa = 0.82 at the streaks and 0.77 for the control tissues) for absence/presence of intercellular space dilatation. Red streak and control biopsies differed significantly (p = 0.0001), with respect to presence of dilated intercellular spaces, with 90.5 % of the former demonstrating this as present compared to 56.1% in the controls. Conclusion: This study supports the concept that esophageal mucosal minimal changes due to reflux is localised and that dilatation of intercellular spaces is an early sign of reflux-induced epithelial damage. The low interobserver variability in the assessment of intercellular space dilatation suggests that this may be a useful variable for assessment of early signs of acid-reflux induced damage to the squamous epithelium of the esophagus by use of light microscopy. Copyrigh

Angiotensin II receptor expression and relation to Helicobacter pylori-infection in the stomach of the Mongolian gerbil

<p>Abstract</p> <p>Background</p> <p>The role of the renin-angiotensin system in gastric physiology and disease has as yet been sparsely explored. The first aim of the study was to investigate the baseline presence and location of angiotensin II receptors (AT1R and AT2R) in the stomach of the Mongolian gerbil. A second aim was to elucidate whether the presence of <it>H. pylori </it>infection is associated with changes in the expression of these receptors.</p> <p>Methods</p> <p><it>H. pylori</it>-negative and <it>H. pylori-</it>infected (strain SS1 or TN2GF4) male Mongolian gerbils were investigated. The stomachs were examined at six or 12 months after inoculation by the use of immunohistochemistry, western blot and microscopic morphometry.</p> <p>Results</p> <p>AT1R and AT2R were located in a variety of cells in the gerbil gastric wall, including a subpopulation of endocrine cells in the antral mucosa and inflammatory cells infiltrating <it>H. pylori</it>-infected stomachs. Gerbils infected with the SS1 strain showed a significantly increased antral AT1R protein expression and an increased number of infiltrating polymorphonuclear leucocytes (PMNs) at 12 months. The AT1R protein expression correlated with the number of PMNs and the antral expression of myeloperoxidase.</p> <p>Conclusions</p> <p>Angiotensin II receptors are present in a variety of cells in the gastric wall of the Mongolian gerbil. The results indicate an influence dependent on the <it>H. pylori </it>strain on the gastric AT1R expression and a relationship between gastric AT1R expression and mucosal PMNs infiltration.</p

The oesophageal mucosa in reflux disease - endoscopic appearance and tissue structure

Gastro-oesophageal reflux disease (GORD) is very common in especially the western world. The cardinal symptoms are heartburn or regurgitations and are caused by the reflux of noxious compounds from the stomach/duodenum to the oesophagus. The first-choice diagnostic method is endoscopy with the observation of erosions or ulcerations (erosive reflux disease; ERD). However, in approximately 50% no erosions are seen on endoscopy despite typical symptoms. These patients are referred to as non-erosive reflux disease (NERD) patients. In the other end of the reflux disease spectrum are the patients developing complications like strictures or metaplastic transformation, i.e. Barrett’s oesophagus. The latter is a known precursor to adenocarcinoma of the oesophagus. During the last three decades there is an increasing incidence of adenocarcinoma of the oesophagus but underlying causes are unknown. Risk assessment as well as surveillance regimes are still based on histopathology but there is an urgent need for bio-markers to improve individual predictions. The renin-angiotensin system (RAS) is well known for its importance in fluid homeostasis. During recent years this regulatory system has also been shown to be an important mediator of inflammation and carcinogenesis. Epidemiological studies have also indicated a lowered incidence of adenocarcinoma in patients on anti-hypertensive treatment with angiotensin converting enzyme (ACE) inhibitors. First, the thesis project addressed the possibility of using the latest advances in endoscopical imaging technology to enhance the diagnostic capability of gastric acid-dependent NERD. A NERD-patient group and healthy subjects were examined by high-resolution magnification endoscopy and seven criteria with potentially diagnostic value were proposed. These criteria were further evaluated by a panel of expert endoscopists. Three of the criteria (triangular indentations, apical mucosal breaks and pinpoint blood vessels) were found to be significantly associated to acidic reflux. However the interobserver agreement between expert endoscopists were found to be poor and therefore they cannot be recommended in everyday clinical practice. Secondly, the thesis elucidates the geographical distribution of known histo-pathological signs of reflux-induced injury in order to evaluate if there were any location in the aboral oesophagus that were more prone to be injured by the refluxate. The results indicate that there is a locus majori in the dorsal aspect of the aboral part of the oesophagus that coincides with endoscopically visible erosions and also with the preferred site of superficial oesophageal adenocarcinomas. A third objective of this thesis was to investigate the distribution of the RAS in the oesophageal mucosa. The RAS system was explored in healthy subjects and patients with erosive reflux disease as well as Barrett’s oesophagus and found to be upregulated in association to both inflammation and increasing grade of dysplasia. Especially ACE was found to be associated to neoplasia and may be considered for future research as a bio-marker-candidate

Helicobacter pylori-Specific CD4(+) T Cells Home to and Accumulate in the Human Helicobacter pylori-Infected Gastric Mucosa

Helicobacter pylori infects the stomach and duodenal mucosa. T cells are important components of the H. pylori-induced immune response, but little is currently known about how these cells are recruited to the infected mucosa. Here, we have characterized stomach and duodenal T cells isolated from H. pylori-infected and noninfected subjects with regard to subtype, expression of homing and chemokine receptors, and in vitro reactivity to H. pylori antigens. Higher numbers of CD4(+) but similar numbers of CD8(+) lamina propria T cells were isolated from stomach biopsies from H. pylori-positive compared to H. pylori-negative individuals. CD4(+) T cells from infected stomach expressed increased levels of the homing receptor L-selectin and the chemokine receptor CCR4 compared to CD4(+) T cells from uninfected stomach. Infected stomach mucosa also contained increased levels of the CCR4 chemokine ligand MDC/CCL22. In contrast, comparable numbers of CD4(+) T cells with similar receptor expression were isolated from the duodenum of H. pylori-positive and H. pylori-negative individuals. In vitro proliferation of mucosal T cells was strongly enhanced by the addition of interleukin-2 (IL-2) and IL-7 to the cell cultures. Using this approach, H. pylori-specific T-cell responses were detected in stomach CD4(+) T cells from H. pylori-positive but not H. pylori-negative individuals. Duodenal T cells from only a few individuals responded to H. pylori stimulation, and the responsiveness was not restricted to H. pylori-positive individuals, suggesting limited H. pylori specificity in the duodenum and possible cross-reactivity with antigens from other bacteria in this compartment. In conclusion, these results suggest that H. pylori-specific CD4(+) T cells preferentially home to and accumulate in the infected stomach and that L-selectin and CCR4/MDC are important for this recruitment

Support for involvement of the renin–angiotensin system in dysplastic Barrett’s esophagus

<p><b>Background and aim:</b> Patients with dysplasia in Barrett’s esophagus (BE) have a considerable risk of developing esophageal adenocarcinoma (EAC). The mucosal expression of the pro-inflammatory angiotensin II receptor type 1 (AT1R) is elevated in these patients, suggesting a role in carcinogenesis. The purpose of this study was to determine whether interference with the renin–angiotensin system (RAS) would influence downstream markers of carcinogenesis.</p> <p><b>Methods:</b> Endoscopic mucosal biopsies from BE patients with low-grade dysplasia (LGD) were sampled before and after a three-week period of RAS-interfering treatment. Thirty patients were randomly allocated to enalapril (ACE inhibitor, 5 mg od), candesartan (AT1R antagonist, 8 mg od), or no drug. The expression of 12 proteins known to be associated with RAS and carcinogenesis was assessed using western blot.</p> <p><b>Results:</b> We found altered expression of several proteins after enalapril treatment (decreased: NFκB, <i>p</i> = .043; NLRP3, <i>p</i> = .050; AMACR, <i>p</i> = .017; and caspase 3, <i>p</i> = .025; increased: p53, <i>p</i> = .050). Candesartan treatment was associated with increased iNOS expression (<i>p</i> = .033). No significant changes were seen in the no-drug group.</p> <p><b>Conclusion:</b> Interference with angiotensin II formation was associated with altered expression of inflammation- and carcinogenesis-related proteins. The present results speak in favor of involvement of angiotensin II in BE dysplasia, but the role of AT1R should be investigated further.</p