Development Of Metaplasia Research Articles

Development of a total colectomy and ileorectal anastomosis rat model to evaluate colonic metaplasia

BackgroundUlcerative colitis is an idiopathic inflammatory condition of the colon that may require surgical intervention including proctocolectomy and either ileal pouch-anal anastomosis or in the pediatric population, low ileorectal anastomosis (IRA). Often, subsequent physiologic alteration (or colonic metaplasia) occurs in the anastomosed small bowel that includes changes in mucin content, villous blunting, and increased expression of WNT5A, a marker of colonic crypt regeneration. We developed a rat low IRA model to assess and study the development of colonic metaplasia. Materials and methodsWe subjected male Sprague–Dawley rats (n = 17) to total colectomy and low IRA surgery and evaluated healing periodically by endoscopic evaluation. The ileum upstream of the anastomosis was assessed by hematoxylin and eosin staining, and the mucin content was measured by high iron diamine-Alcian blue staining. Wnt5a transcripts were quantified by reverse transcription and quantitative polymerase chain reaction at the 8-wk study end point. ResultsAlthough no gross endoscopic evidence of inflammation was seen throughout the course of the study, colonic metaplasia in the small bowel was detected in 7 out of 10 (70%) rats at the study end point. In rats with colonic metaplasia, enhanced expression of Wnt5a was evident at the study end point compared to levels in the terminal ileum at the time of surgery. ConclusionsWithin 4-8 wk, the majority of rats subjected to IRA developed colonic metaplasia defined by villous blunting, changes in mucin content, and increased expression of Wnt5a. This model provides a method to study small bowel colonic metaplasia.

Quantitative Shotgun Proteomics Unveils Candidate Novel Esophageal Adenocarcinoma (EAC)-specific Proteins

Esophageal cancer is the eighth most common cancer worldwide and the majority of patients have systemic disease at presentation. Esophageal adenocarcinoma (OAC), the predominant subtype in western countries, is largely resistant to current chemotherapy regimens. Selective markers are needed to enhance clinical staging and to allow targeted therapies yet there are minimal proteomic data on this cancer type. After histological review, lysates from OAC and matched normal esophageal and gastric samples from seven patients were subjected to LC MS/MS after tandem mass tag labeling and OFFGEL fractionation. Patient matched samples of OAC, normal esophagus, normal stomach, lymph node metastases and uninvolved lymph nodes were used from an additional 115 patients for verification of expression by immunohistochemistry (IHC).Over six thousand proteins were identified and quantified across samples. Quantitative reproducibility was excellent between technical replicates and a moderate correlation was seen across samples with the same histology. The quantitative accuracy was verified across the dynamic range for seven proteins by immunohistochemistry (IHC) on the originating tissues. Multiple novel tumor-specific candidates are proposed and EPCAM was verified by IHC.This shotgun proteomic study of OAC used a comparative quantitative approach to reveal proteins highly expressed in specific tissue types. Novel tumor-specific proteins are proposed and EPCAM was demonstrated to be specifically overexpressed in primary tumors and lymph node metastases compared with surrounding normal tissues. This candidate and others proposed in this study could be developed as tumor-specific targets for novel clinical staging and therapeutic approaches.

Reflux esophagitis and its role in the pathogenesis of Barrett's metaplasia.

Reflux esophagitis damages the squamous epithelium that normally lines the esophagus, and promotes replacement of the damaged squamous lining by the intestinal metaplasia of Barrett's esophagus, the precursor of esophageal adenocarcinoma. Therefore, to prevent the development of Barrett's metaplasia and esophageal adenocarcinoma, the pathogenesis of reflux esophagitis must be understood. We have reported that reflux esophagitis, both in a rat model and in humans, develops as a cytokine-mediated inflammatory injury (i.e., cytokine sizzle), not as a caustic chemical injury (i.e., acid burn), as traditionally has been assumed. Moreover, reflux induces activation of hypoxia inducible factor (HIF)-2α, which enhances the transcriptional activity of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) causing increases in pro-inflammatory cytokines and in migration of T lymphocytes, an underlying molecular mechanism for this cytokine-mediated injury. In some individuals, reflux esophagitis heals with Barrett's metaplasia. A number of possibilities exist for the origin of the progenitor cells that give rise to this intestinal metaplasia including those of the esophagus, the proximal stomach, or the bone marrow. However, intestinal cells are not normally found in the esophagus, the stomach, or the bone marrow. Thus, the development of Barrett's intestinal metaplasia must involve some molecular reprogramming of key developmental transcription factors within the progenitor cell, a process termed transcommitment, which may be initiated by the noxious components of the gastric refluxate. This review will highlight recent studies on the pathogenesis of reflux esophagitis and on reflux-related molecular reprogramming of esophageal squamous epithelial cells in the pathogenesis of Barrett's metaplasia.

Transitional metaplasia in intestinal epithelium of rats submitted to intestinal cystoplasty and treatment with L -lysine.

To evaluated the effects of L-lysine on the intestinal and urothelial epithelia in cystoplasty in rats. Twenty-eight 9-week-old rats were assigned to 4 groups: Group A (n=8) cystoplasty followed by administration of L-lysine (150 mg/kg body weight by gavage) for 30 weeks; Group B (n=8) cystoplasty + water for 30 weeks; Group C (n=6) L-lysine for 30 weeks; Group D (n=6) water for 30 weeks. On histopathology with hematoxylin and eosin, mild to moderate hyperplasia transitional was observed in at the site of anastomosis in all animals submitted to cystoplasty (Groups A and B), but "transitional metaplasia" of the intestinal glandular epithelium was more accentuated in Group A (p=0.045). No inflammatory cells, dysplasia or abnormalities were observed. Staining with Alcian blue revealed a substantial reduction of goblet cells and mucins in the colon segment (Groups A and B). The administration of L-lysine to rats accelerated the development of transitional metaplasia in the epithelium of the colon segment in cystoplasty.

190 - The Involvement of Epigenetic Regulation in the Initiation of Metaplasia Development in the Stomach

190 - The Involvement of Epigenetic Regulation in the Initiation of Metaplasia Development in the Stomach

High expression of Claudin-2 in esophageal carcinoma and precancerous lesions is significantly associated with the bile salt receptors VDR and TGR5

BackgroundClaudins are a family of integral membrane proteins and are components of tight junctions (TJs). Many TJ proteins are known to tighten the cell structure and maintain a barrier. Claudin-2 forms gated paracellular channels and allows sodium ions and other small positively charged ions to cross between adjacent cells. Recently, we found that vitamin D receptor (VDR) enhanced Claudin-2 expression in colon and that bile salt receptors VDR and Takeda G-protein coupled receptor5 (TGR5) were highly expressed in esophageal adenocarcinoma (EAC) and precancerous lesions. Here, we examined the expression of Claudin-2 in EAC and precancerous lesions and its association with VDR and TGR5 expression.MethodsClaudin-2 expression was examined by immunohistochemistry on tissue microarrays, containing EAC, high grade dysplasia (HGD), low grade dysplasia (LGD), Barrett’s esophagus (BE), columnar cell metaplasia (CM), squamous cell carcinoma (SCC), and squamous epithelium (SE) cases. Intensity (0 to 3) and percentage were scored for each case. High expression was defined as 2–3 intensity in ≥ 10% of cells.ResultsClaudin-2 was highly expressed in 77% EAC (86/111), 38% HGD (5/13), 61% LGD (17/28), 46% BE (18/39), 45% CM (29/65), 88% SCC (23/26), and 14% SE (11/76). It was significantly more highly-expressed in EAC, SCC and glandular lesions than in SE and more in EAC than in BE and CM. A significant association was found between Claudin-2 expression and VDR and TGR5 expression. No significant association was found between expression of Claudin-2 and age, gender, grade, stage, or patients’ survival time in EAC and SCC.ConclusionsWe conclude that Claudin-2 expression is significantly associated with bile acid receptors VDR and TGR5 expression. Our studies identify a novel role of a tight junction protein in the development and progression of esophageal mucosal metaplasia, dysplasia and carcinoma.

A signalling cascade of IL-33 to IL-13 regulates metaplasia in the mouse stomach

ObjectiveAlternatively activated macrophages (M2) are associated with the progression of spasmolytic polypeptide-expressing metaplasia (SPEM) in the stomach. However, the precise mechanism(s) and critical mediators that induce SPEM are unknown.DesignTo determine...

Vaginal Infections of Albanian women Infected with HPV and their impact in intraepithelial cervical lesions evidenced by Pap test.

Background:Cervical cytology is the best single method for large screening of the population in identifying precancerous lesions of the uterine cervix.Aim:To estimate the frequency of human papillomavirus (HPV) positivity in a group of Albanian women, the prevalence of vaginal coinfections, and the relationship of coinfections with HPV, as well as their role in metaplasia or cervical intraepithelial lesions (CIN).Materials and Methods:In this retrospective study, 2075 vaginal smears were examined. The Papanicolaou stain was used for all slides. The New Bethesda System 2001 was used for the interpretations of the smears. Data analysis was completed using the Statistical Package for the Social Sciences version 19.0.Results:Prevalence of HPV positivity was 43.9% with an average age of 35.48 ± 9.27 years. Candida coinfection resulted in 57.8% of HPV positive women with a significant relationship between them. Gardnerella coinfection resulted in 36 (23%), mixed flora in 34 (8%), and Trichomonas vaginalis in 50% of HPV positive woman. Among the women with positive HPV, 19% had CIN, 8% had metaplasia, and 1% had metaplasia and CIN; 9% of the women with HPV had CIN1 and one of the coinfections.Conclusions:There is a strong relationship between CIN1 and HPV positivity as well as between CIN1 and coinfections. HPV infection is a major factor contributing to metaplasia, and bacterial coinfections in HPV positive women have a statistically significant impact in the development of metaplasia.

A Favorable Response of Dysplastic Barrett’s Refractory to Ablation Therapy Only after Initiation of an Alginate Solution as Add-on Therapy

Alginates have been shown not only to be beneficial in their relief of symptomatic post-prandial gastroesophageal reflux, but there is also evidence that they may inhibit reflux, including bile acids and pepsin, and in turn attenuate and even prevent the activation and up-regulation of molecules associated with the development of metaplasia and cancer of the esophagus. Here we present the case of a patient with Barrett's esophagus with high-grade dysplasia (HGD) which was initially unresponsive to endoscopic radiofrequency ablation therapy and cryotherapy for highgrade dysplasia. Following initiation of therapy with an alginate solution in addition to twice daily proton pump inhibitor (PPI) therapy, the patient showed a favorable response and eventual complete eradication of his dysplastic Barrett's. The patient's course is suggestive that the alginate solution, through reflux inhibition, prevented persistent esophageal cell changes which occur secondary to gastric and bile acid exposure, thus allowing development of neosquamous epithelium. This case is intriguing with regard to the role of alginates in creating a favorable environment for esophageal healing when treating Barrett's esophagus with high-grade dysplasia.

Fatty acids in a high-fat diet potentially induce gastric parietal-cell damage and metaplasia in mice.

Obesity is associated with risk of adenocarcinoma in the proximal stomach. We aimed to identify the links between dietary fat and gastric premalignant lesions. C57BL/6 mice were fed high fat diet (HFD), and gastric mucosa was histologically analysed. Morphological changes were also analysed using an electron microscope. Transcriptome analysis of purified parietal cells was performed, and non-parietal gastric corpus epithelial cells were subjected to single-cell gene-expression profiling. Composition of gastric contents of HFD-fed mice was compared with that of the HFD itself. Lipotoxicity of free fatty acids (FFA) was examined in primary culture and organoid culture of mouse gastric epithelial cells in vitro, as well as in vivo, feeding FFA-rich diets. During~8-20weeks of HFD feeding, the parietal cells of the stomach displayed mitochondrial damage, and a total of 23% of the mice developed macroscopically distinct metaplastic lesions in the gastric corpus mucosa. Transcriptome analysis of parietal cells indicated that feeding HFD enhanced pathways related to cell death. Histological analysis and gene-expression profiling indicated that the lesions were similar to previously reported precancerous lesions identified as spasmolytic polypeptide-expressing metaplasia. FFAs, including linoleic acid with refluxed bile acids were detected in the stomachs of the HFD-fed mice. In vitro, FFAs impaired mitochondrial function and decreased the viability of parietal cells. In vivo, linoleic acid-rich diet, but not stearic acid-rich diet induced parietal-cell loss and metaplastic changes in mice. Dietary lipids induce parietal-cell damage and may lead to the development of precancerous metaplasia.

A knockin mouse model for human ATP4aR703C mutation identified in familial gastric neuroendocrine tumors recapitulates the premalignant condition of the human disease and suggests new therapeutic strategies.

ABSTRACTBy whole exome sequencing, we recently identified a missense mutation (p.R703C) in the human ATP4a gene, which encodes the proton pump responsible for gastric acidification. This mutation causes an aggressive familial type I gastric neuroendocrine tumor in homozygous individuals. Affected individuals show an early onset of the disease, characterized by gastric hypoacidity, hypergastrinemia, iron-deficiency anemia, gastric intestinal metaplasia and, in one case, an associated gastric adenocarcinoma. Total gastrectomy was performed as the definitive treatment in all affected individuals. We now describe the generation and characterization of a knockin mouse model for the ATP4aR703C mutation to better understand the tumorigenesis process. Homozygous mice recapitulated most of the phenotypical alterations that were observed in human individuals, strongly suggesting that this mutation is the primary alteration responsible for disease development. Homozygous mice developed premalignant condition with severe hyperplasia, dysplasia and glandular metaplasia in the stomach. Interestingly, gastric acidification in homozygous mice, induced by treatment with 3% HCl acid in the drinking water, prevented (if treated from birth) or partially reverted (if treated during adulthood) the development of glandular metaplasia and dysplasia in the stomach and partially rescued the abnormal biochemical parameters. We therefore suggest that, in this model, achlorhydria contributes to tumorigenesis to a greater extent than hypergastrinemia. Furthermore, our mouse model represents a unique and novel tool for studying the pathologies associated with disturbances in gastric acid secretion.

Abstract 4178: Pigs as a new weapon against cancer: Modeling solid tumors in porcine

Abstract Widely-used genetically modified mice have revolutionized the field of cancer research by providing reliable in vivo systems with similar, if not identical, molecular alterations. Furthermore, Cre/Lox technology has afforded greater tissue specificity, with many of the developing cancer phenotypes recapitulating those observed in humans. However, despite these strengths, there are a number of notable limitations when comparing mice to humans including small sample sizes, dramatic differences in physiology, and often dissimilar drug responses. Pig models would alleviate these shortcomings if they were to have a repertoire of gene signatures observed in human cancer, like those engineered in mice. Therefore, to achieve this goal, we have engineered a pig model with the Cre-responsive transgene encoding KRASG12D and TP53R167H. Hence, tissue-specific targeted Cre would generate simultaneous expression of mutant KRAS and p53 alleles to induce cellular changes leading to cancer. Pig pancreases were injected with adenovirus containing a cre expression vector (adenoCre) in an attempt to generate a model of pancreatic cancer. Initial injections of adenoCre into the parenchymal body of the pancreas led to the development of acinar-ductal metaplasia (ADM), though the clear predominant histotype was leiomyosarcoma immediately adjacent to the pancreas. Pancreatic ADM was characterized by concomitant localization of amylase (acinar cell marker) and CK19 (ductal cell marker) in the same pancreatic acinus, with an occasional few cells expressing both cell markers. These lesions were further characterized and exhibited increased proliferation via PCNA staining, as well the development of surrounding desmoplastic stroma (enhanced trichrome, vimentin, and aSMA staining; a marker of pancreatic stellate cells) with a robust inflammatory component (strong CD11b and CAE staining). Based on the lack of pancreas specificity, the experiment was repeated by injecting adenoCre into the main pancreatic duct. This 10-month-old pig appears relatively healthy after, which was expected considering this was a fully adult pig prior to manipulation. We will fully access this pig in 2 months to determine if strict pancreatic duct injection of adenoCre induces ADM, neoplastic disease, and/or ductal adenocarcinoma. Based on these encouraging findings, we anticipate having a robust model of pancreatic cancer in the pig, and plan to extend this study to generate models of other solid tumors with high rates of KRAS and p53 mutations. These porcine models may significantly impact preclinical studies, as diseases induced in pigs are likely more physiologically relevant to those in humans, with a potentially similar pharmacokinetic profile following drug treatment. Indeed, due to the size of the organs and volume of blood, samples can be more readily shared among multiple groups of investigators facilitating greater collaboration and expanding future research. Citation Format: Andrew Diaz, Daniel Principe, Brian DeCant, Paul J. Grippo, Laurie Rund, Lawrence Schook. Pigs as a new weapon against cancer: Modeling solid tumors in porcine. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4178.

Genetic susceptibility to Barrett's oesophagus: Lessons from early studies.

Barrett’s oesophagus (BO) is a common condition, predisposing strongly to the development of oesophageal adenocarcinoma (OAC). Consequently, there has been considerable effort to determine the processes involved in the development of BO metaplasia, and ultimately develop markers of patients at risk. Whilst a number of robust acquired risk factors have been identified, a genetic component to these and the apparent increased susceptibility of certain individuals has long been suspected. This has been evidenced in part by linkage studies, but subsequently two recent genome-wide association studies (GWAS) have suggested mechanisms underlying the heritability of BO, as well as providing the first direct evidence at modern levels of statistical significance. This review discusses BO heritability, in addition to that of individual variants and genes reported to be associated with BO to date. Through this, we identify a number of plausible associations, although often tempered by issues of methodology, and discuss the priorities and need for future research.

Helicobacter pylori as a crucial factor in intestinal metaplasia development of gastric mucosa

<p class="BodyText1"><em>Helicobacter pylori</em> (<em>H. pylori</em>) is detected on the surface of gastric epithelium and in goblet cells, predominantly in patients with chronic atrophic gastritis and incomplete intestinal metaplasia (IM). <em>H. pylori</em> infection persistence leads to the formation of gastrointestinal phenotype of IM. <em>H. pylori</em> can be considered as an etiological factor of IM. It inhibits the expression of SOX2 in gastric epithelial cells, hence activating transcription factor CDX2 as a counterpart to <em>MUC5AC</em> gene inhibition and <em>MUC2</em> gene induction. Thus, in metaplastic cells, programming differentiation after intestinal phenotype will develop. The role of <em>H. pylori</em> in the origin of intestinal metaplasia of gastric mucosa was defined in this study to elucidate the probable mechanism of cell reprogramming. The activation of CDX2, with simultaneous inactivation and decreased number of genes (<em>e.g.</em>, <em>SHH</em>, <em>SOX2</em>, and <em>RUNX3</em>) responsible for gastric differentiation, was identified to cause the appearance of IM. </p>

Stomach-Specific Activation of Oncogenic KRAS and STAT3-Dependent Inflammation Cooperatively Promote Gastric Tumorigenesis in a Preclinical Model.

About 5% to 10% of human gastric tumors harbor oncogenic mutations in the KRAS pathway, but their presence alone is often insufficient for inducing gastric tumorigenesis, suggesting a requirement for additional mutagenic events or microenvironmental stimuli, including inflammation. Assessing the contribution of such events in preclinical mouse models requires Cre recombinase-mediated conditional gene expression in stem or progenitor cells of normal and transformed gastric epithelium. We therefore constructed a bacterial artificial chromosome containing transgene (Tg), comprising the regulatory elements of the trefoil factor 1 (Tff1) gene and the tamoxifen-inducible Cre recombinase (CreERT2)-coding sequence. The resulting Tg(Tff1-CreERT2) mice were crossed with mice harboring conditional oncogenic mutations in Kras or Braf The administration of tamoxifen to the resulting adult Tg(Tff1-CreERT2);Kras(LSL-G12D/+) and Tg(Tff1-CreERT2);Braf(LSL-V600E/+) mice resulted in gastric metaplasia, inflammation, and adenoma development, characterized by excessive STAT3 activity. To assess the contribution of STAT3 to the spontaneously developing gastric adenomas in gp130(F/F) mice, which carry a knockin mutation in the Il6 signal transducer (Il6st), we generated Tg(Tff1-CreERT2);Stat3(fl/fl);gp130(F/F) mice that also harbor a conditional Stat3 knockout allele and found that tamoxifen administration conferred a significant reduction in their tumor burden. Conversely, excessive Kras activity in Tg(Tff1-CreERT2);Kras(LSL-G12D/+);gp130(F/F) mice promoted more extensive gastric inflammation, metaplastic transformation, and tumorigenesis than observed in Tg(Tff1-CreERT2);Kras(LSL-G12D/+) mice. Collectively, our findings demonstrate that advanced gastric tumorigenesis requires oncogenic KRAS or BRAF in concert with aberrant STAT3 activation in epithelial precursor cells of the glandular stomach, providing a new conditional model of gastric cancer in which to investigate candidate therapeutic targets and treatment strategies. Cancer Res; 76(8); 2277-87. ©2016 AACR.

Pathogenesis of Barrett s Esophagus

Barrett’s esophagus (BE) is characterized as histologic evidence of intestinal metaplasia is present in distal esophageal epithelium and is an important pathology because it is the major risk factor for developing esophageal adenocarcinoma (EAC). It’s well known that chronic gastroesophageal reflux disease (GERD) leads to the development of metaplasia. However, the cellular and molecular mechanism of the replacement of squamous esophageal epithelium with a columnar type is largely unknown. Efforts to understand the pathogenesis of BE and its disposition to EAC have been increasing over the previous 2 decades. This review aims to explore current data on the major risk factors, origin, genetic changes of BE, provide an insight into the molecular biomarkers related with BE and seek for possible development of therapies that could prevent BE from progressing to EAC.

Anatomical predilection of intestinal metaplasia based on 78,335 endoscopic cases.

Background/Aims:Gastric intestinal metaplasia (IM) is an important risk factor for intestinal-type gastric carcinoma, and successful treatment critically depends on its timely detection. In order to guide appropriate endoscopic surveillance, objective knowledge on the anatomical predilection of intestinal metaplasia development is urgently needed.Materials and Methods:A total of 78,335 cases who underwent gastroduodenoscopy from 2008 to 2013 in Jiangsu and Anhui provinces in China, were studied. Demographic and clinical characteristics, as well as biopsy location and histological results, were analyzed.Results:This study revealed that intestinal metaplasia incidence was 28.5% in angulus, 20.24% in lesser curvature of the antrum, and 25.48% in corpus; and all these were significantly higher than those observed in other sites (P < 0.01). Histological grading of intestinal metaplasia in the lesser curvature of the antrum and angulus was generally worse than the grading observed in the greater curvature of the antrum. For Helicobacter pylori-positive patients, acute inflammation was more severe in the lesser curvature of the antrum compared with the greater curvature. In the H. Pylori-negative group, both acute and chronic inflammations were more severe in the lesser curvature of the antrum.Conclusions:The angulus, lesser curvature in the antrum, and corpus are most prone to the development of intestinal metaplasia. Inflammation is most severe in the lesser curvature of the antrum, which corresponds to a higher predilection to develop intestinal metaplasia at this site. The lesser curvature of the antrum and corpus require the most attention during endoscopic biopsy surveillance.

The homing receptor CD44 is involved in the progression of precancerous gastric lesions in patients infected with Helicobacter pylori and in development of mucous metaplasia in mice

Infection with Helicobacter pylori (H. pylori) leads to inflammatory events that can promote gastric cancer development. Immune cells transition from the circulation into the infected mucosa through the interaction of their receptors and ligands in the endothelial compartment. CD44 expression is increased in advanced gastric lesions. However, the association of this molecule with the progression of these lesions over time has not been investigated. In addition, there is a lack of understanding of the CD44-dependent cellular processes that lead to gastritis, and possibly to gastric cancer. Here we studied H. pylori-positive subjects with gastric lesions that ranged from multifocal atrophic gastritis to dysplasia to determine gene expression changes associated with disease progression over a period of 6 years. We report that CD44 expression is significantly increased in individuals whose gastric lesions progressed along the gastric precancerous cascade. We also show that CD44−/− mice develop less severe and less extensive H. pylori-induced metaplasia, and show fewer infiltrating Gr1+ cells compared to wild type mice. We present data suggesting that CD44 is associated with disease progression. Mechanisms associated with these effects include induction of interferon gamma responses.

Immature myeloid progenitors promote disease progression in a mouse model of Barrett's-like metaplasia.

Cdx2, an intestine specific transcription factor, is expressed in Barrett's esophagus (BE). We sought to determine if esophageal Cdx2 expression would accelerate the onset of metaplasia in the L2-IL-1β transgenic mouse model for Barrett's-like metaplasia. The K14-Cdx2::L2-IL-1β double transgenic mice had half as many metaplastic nodules as control L2-IL-1β mice. This effect was not due to a reduction in esophageal IL-1β mRNA levels nor diminished systemic inflammation. The diminished metaplasia was due to an increase in apoptosis in the K14-Cdx2::L2-IL-1β mice. Fluorescence activated cell sorting of immune cells infiltrating the metaplasia identified a population of CD11b+Gr-1+ cells that are significantly reduced in K14-Cdx2::L2-IL-1β mice. These cells have features of immature granulocytes and have immune-suppressing capacity. We demonstrate that the apoptosis in K14-Cdx2::L2-IL-1β mice is CD8+ T cell dependent, which CD11b+Gr-1+ cells are known to inhibit. Lastly, we show that key regulators of CD11b+Gr-1+ cell development, IL-17 and S100A9, are significantly diminished in the esophagus of K14-Cdx2::L2-IL-1β double transgenic mice. We conclude that metaplasia development in this mouse model for Barrett's-like metaplasia requires suppression of CD8+ cell dependent apoptosis, likely mediated by immune-suppressing CD11b+Gr-1+ immature myeloid cells.

Duodenogastral reflux and its influence on manifestation of morphological changes of gastric mucosa.

Among the diseases of the gastroduodenal zone chronic gastritis (CG) occupies one of the leading positions. One of the main forms of CG is reflux gastritis (RG) based on long-term location of duodenal content in the gastric antrum , so-called duodenal reflux (DR). It is w ell known that stable inflammatory response of the gastric mucosa (GM) appears under the influence of bile acid and gastric juice , leading to chronic antral gastritis followed by gradual development of atrophy, metaplasia and dysplasia appearance. Therefore the aim of our work was to investigate the influence of the DR on the course of chronic hepatitis and morphological changes in the gastric mucosa. We observed 70 patients with chronic RG, aged from 22 to 59 years, average age – 43,5±1,2 years. The control group consisted of 25 healthy individuals of both sexes aged from 19 to 39 years. As a result it was found out that pain and dyspeptic syndromes caused problems most of all. While studying the content of bile acids in gastric juice of all patients examined it was higher (1,42±0,05 g/L) in comparison with the control group (0,65±0,04 g/L). C ontent of bile acids in groups of RG patients with atrophy and without it was analyzed. T he role of DR as an independent factor of recomposing changes in GM in chronic RG was proved.