Altered glycosylation in secreting cells of the gastric glands of aquaporin-4-deficient mice.

Aquaporins (AQPs) are important for water transport in the gastrointestinal tract. Changes in their expression and/or localization could cause in disorders and be used as therapeutic targets. Aquaporin-4 (AQP4) is expressed predominantly on the basolateral membrane of the parietal cells in the corpus of the murine gastric glands. Although the secretion of gastric juice is not affected in AQP4-deficient knockout, we evaluated by light microscopy whether the lack of AQP4 affects the glycopatterns of secreting gastric cells. Wild type (WT) and AQP4-deficient knockout mice (KO) were fed a standard diet ad libitum before sacrifice. Segments of stomach corpus were collected, fixed in buffered formalin, and embedded in paraffin wax. Sections, 5-µm thick, were analyzed by histochemical methods (Periodic acid-Schiff, Alcian Blue pH 2.5), and binding of lectins specific to GalNAc (SBA, DBA), Gal (PNA) GlcNAc (WGA, GSAII) mannose and/or glucose (ConA), and fucose (UEA-I, AAA, LTA). Immunohistochemical methods such as anti-Muc6 for neck cells and anti- ß- H+/K+-ATPase for parietal cells were also performed. Compared to WT mice, in the mucous cells of KO lower amounts of glycans with galactosyl/galactosaminylated, glycosyl/glycosaminylated, and fucosylated residues were observed; lower fucosylation resulted also in the parietal cells. The observed differences of KO in respect to WT could lead to severer pathological conditions. RESEARCH HIGHLIGHTS: Glycopatterns in gastric glands were compared between wild type (WT) and AQP4-deficient knockout (KO) mice by histochemical and lectin-binding methods. In the mucous cells of KO lower amounts of glycans with galactosyl/galactosaminylated, glycosyl/glycosaminylated and fucosylated residues were observed. In the parietal cells lower fucosylation also resulted. AQP4-deficiency affects glycosylation and could result in altered functionality and pathological conditions.

Gastritis Cystica Profunda: A Rare Disease, a Challenging Diagnosis, and an Uncertain Malignant Potential: A Case Report and Review of the Literature.

Gastritis cystica profunda (GCP) has been defined as a rare submucosal benign gastric lesion with cystic gland growth. Due to its unclear etiopathogenesis, this lesion is often misdiagnosed and mistaken for other gastric masses. Currently, a standardized treatment for GCP lesions is still missing. Here, we illustrate a case of a patient admitted to our general surgery department for melena and general discomfort. No history of peptic ulcer or gastric surgery was present. Upper GI endoscopy was performed, showing a distal gastric lesion with a small ulceration on the top. CT-scan and endoscopic ultrasound confirmed the presence of the lesion, compatible with a gastric stromal tumor, without showing any eventual metastasis. Surgical gastric resection was performed. Histological findings were diagnostic for GCP, with cistically ectasic submucosal glands, chronic inflammation, eosinophilic infiltration and foveal hyperplasia. GCP is a very exceptional cause of upper-GI bleeding with specific histological features. Its diagnosis as well as its therapy are challenging, resulting in several pitfalls. Even though it is a rare entity, GCP should always be considered in the differential diagnosis of gastric submucosal lesions.

A case of early gastric cancer resembling a subepithelial lesion diagnosed by endoscopic ultrasound-guided fine needle aspiration.

We present a case of early gastric cancer resembling a subepithelial lesion (GCSEL) derived from the submucosal ectopic gastric glands (SEGGs), diagnosed using endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). A 55-year-old woman was referred to our hospital for the investigation of a subepithelial lesion (SEL). Contrast computed tomography and esophagogastroduodenoscopy revealed two SELs in the greater curvature of the fundus and the posterior wall of the upper body of the stomach. EUS revealed a hypoechoic lesion in the submucosa and suggested partial invasion into the muscularis propria of the greater curvature of the fundus, and an anechoic lesion in the submucosa of the posterior wall of the upper body. The different diagnosis for the SEL in the fundus was GCSEL, neuroendocrine tumor, malignant lymphoma, and gastric adenocarcinoma of fundic gland type. EUS-FNA findings suggested adenocarcinoma. The patient underwent a laparoscopic proximal gastrectomy. Pathological findings confirmed a differentiated tubular adenocarcinoma derived from the SEGG, which partially invaded into the submucosa of the surrounding gastric wall without lymphovascular invasion or lymph node metastasis. The patient has been recurrence-free after 10 months of follow-up. EUS should be performed for SELs followed by EUS-FNA for lesions, such as GCSEL, that require early intervention.

Morphogen Signals Shaping the Gastric Glands in Health and Disease.

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

Functional morphology of cardiac stomach of Nile catfish (Clarias gariepinus): Histological, scanning, and ultrastructural studies.

The present study was done on 20 adult specimens of Nile catfish (Clarias gariepinus) to demonstrate the morphological characteristics of the cardiac region of the stomach. The cardiac mucosa was characterized by a large number of well-defined long folds. The surface epithelial cells were simple columnar type covered with distinct microvilli and connected by desmosomes. Few PAS- and AB- positive goblet cells were found between the surface epithelium. In addition, many lymphocytes, macrophages, and blood capillaries were seen in the epithelial layer. The lamina propria was exclusively occupied by simple branched gastric (cardiac) glands that fill most of the thickness of the mucosa and open into gastric pits. The gastric glands were composed of numerous secretory tubules that were lined with one type of cells with a cytoplasm containing numerous electron-dense granules, well-developed rER, mitochondria, and a large number of free ribosomes. Moreover, macrophages were distributed in the lamina propria and submucosa. Telocytes were observed in the cardiac region for the first time around the glands, blood vessels, between the muscular layer, and in the serosa. A large number of mast cells could be identified in the submucosa around the blood vessels. The presence of many immune cells in the wall of the cardiac stomach suggests involvement in immune response in addition to its digestive function. RESEARCH HIGHLIGHTS: The study exposed many cell types in the wall of the cardiac stomach of Nile catfish including mast cells, lymphocytes, and neutrophils that suggests an involvement in the immune response. The current study is the first one to highlight the distribution of telocytes in the fish stomach.

Identification of sugar moieties in chief cells of the rat fundic gastric glands.

Many studies have been conducted to determine the composition of the glycoconjugates of the mucus-secreting cells of the fundic glands of the stomach. However, the chief cells of these glands have been largely ignored because they secrete mainly zymogens with a lower glycosylation. The aim of this work was to analyze the glycoconjugates of the gastric chief cells by a battery of 17 different lectins, recognizing Fucose, N-acetylgalactosamine, Galactose, N-acetylneuraminic acid, N-acetylglucosamine and Mannose containing oligosaccharides. Histochemical techniques were performed with several lectins and also combined with two pre-treatments; ß-elimination, which removes O-linked oligosaccharides, and incubation with Peptide-N-Gycosidase F, which removes N-linked oligosaccharides. In addition, acid hydrolysis was performed before WGA histochemistry, and incubation with glucose oxidase before Con A labeling. Many lectins did not stain the chief cells. In addition, the presence of O-glycans in the apical cell membrane was demonstrated with the lectins AAL, HPA, MPA/MPL, PNA, RCA-I, and WGA. Some of these O-glycans were resistant to short-term ß-elimination pre-treatments. Mannose-binding lectins stained the basal cytoplasm of the chief cells. The level of glycosylation of the chief cells was lower than that of the mucous cells. The presence of O-glycans in the apical cell membrane is consistent with the presence of mucins such as MUC1 in the apical membrane of chief cells. Moreover, Mannose-binding lectins revealed N-glycosylation in the basal cytoplasm. The knowledge of gastric chief cell glycoconjugates is relevant because of their potential involvement not only in in physiological but also in pathological processes, such as cancer.

Gastric MiNEN Arising from the Heterotopic Gastric Glands.

An 80-year-old woman presented with a 30-mm protruding lesion-like submucosal tumor with a central depression located at the anterior wall of the upper gastric body. The depressed area had a well-demarcated margin, while the other area was covered by a non-neoplastic mucosa. A biopsy specimen revealed neuroendocrine carcinoma. Endoscopic ultrasonography revealed a heterogeneous mass with a clearly distinguished border in the submucosal layer. The mass had two distinct areas adjacent to each other. In addition, a hypoechoic zone was observed on the margin of the mass. Distal gastrectomy was performed. The final diagnosis was a mixed neuroendocrine-non-neuroendocrine neoplasm arising from the heterotopic gastric gland.

Early gastric cancer with diffuse heterotopic gastric glands and granular cell tumors mimicking advanced gastric cancer.

INTRODUCTION: Heterotopic gastric grands (HGGs) are gastric grands that are observed in the submucosa and are considered to be paracancerous lesions or precursors of gastric cancer (GC). Granular cell tumors (GCTs) are benign neural origin tumors. Gastrointestinal GCTs are rare and gastric GCTs are seldom seen. We report the case of a patient who was diagnosed with early GC with diffuse HGGs affecting the whole stomach and two GCTs mimicking advanced GC. PRESENTATION OF CASE: The patient is a 71-year-old male with epigastric discomfort. Gastrointestinal endoscopy revealed an ulcerated lesion at the mid-gastric body. A biopsy specimen indicated adenocarcinoma. Moreover, gastrointestinal endoscopy revealed a submucosal tumor at the posterior wall and multiple transparent protuberances across the entire stomach. Computed tomography demonstrated diffuse gastric wall thickening with lymphadenopathies. Total gastrectomy was performed under the preoperative diagnosis of advanced GC with lymph node metastases. The pathological diagnosis was adenocarcinoma invading submucosal stroma without lymph node metastasis, two GCTs, and diffuse HGGs affecting whole stomach. DISCUSSION: Preoperative diagnosis of GC depth or range associated with HGGs is often difficult. Although diffuse HGGs are sometimes observed, there is no previous report of a case of HGGs with whole gastric wall thickening observed by computed tomography. As a result, this case was overdiagnosed as advanced GC. Although the relationship between GCTs and HGGs or GC is unclear, there is no case report of GCTs accompanied by HGGs or GC. CONCLUSION: This case report suggested that cautious preoperative assessment for GC co-occurring with HGGs is required.

Gastric adenocarcinoma of fundic gland type spreading to heterotopic gastric glands.

Herein, we present a case of gastric adenocarcinoma of fundic gland type (GA-FG) spreading to heterotopic gastric glands (HGG) in the submucosa. A 58-year-old man with epigastric pain was referred to our hospital and underwent an esophagogastroduodenoscopy. A Borrmann type II gastric cancer at the antrum and a 10 mm submucosal tumor-like lesion in the lesser curvature of the upper third of the stomach were detected. Histological examination of the biopsy specimens obtained from the submucosal tumor-like lesion suggested a GA-FG. Therefore, endoscopic submucosal dissection was performed as excisional biopsy, and histopathological examination of the resected specimen confirmed a GA-FG and HGG proximal to the GA-FG. Although the GA-FG invaded the submucosal layer slightly, the submucosal lesion of the GA-FG had a poor stromal reaction and was located just above the HGG in the submucosa. Therefore, we finally diagnosed the lesion as a GA-FG invading the submucosal layer by spreading to HGG.

Characterization of Ostertagia ostertagi annexin-like proteins at different developmental stages.

Ostertagiosis remains an economically important parasitic disease in cattle in the temperate regions of the world. Repeated exposures to Ostertagia ostertagi in calves cause significant pathology in the abomasum but elicit little protective immunity. The larvae use the host's gastric glands as a niche for development, where the parasite completes its parasitic stages, while in the gastric glands, the larvae must down-regulate the host inflammatory immune responses. Annexin (ANX) A1, commonly found in most eukaryotes, is heavily involved in controlling anti-inflammatory responses by binding receptors on leukocytes. We hypothesized, therefore, that parasite proteins of the ANX family may be involved in host-parasite interactions during ostertagiosis. BLASTN search with the bovine ANXA1 identified two families of Oos-ANX like proteins (Oos-ANXL), each of which was highly conserved at the genetic level and identical at the amino acid sequence level. Oos-ANXL-1 is encoded by two transcripts and Oos-ANXL-2 by 20 transcripts. The present study characterized one Oos-ANXL, representing the most abundant Oos-ANXL, which was further defined as Oost-ANXL-2.1. Oos-ANXL-2.1 with a coding sequence of 519 bp was PCR-amplified, cloned, and expressed. Oos-ANXL-2.1 was immunolocalized to both L3 and adult, but not L4. The staining appeared to be associated with the gut and hypodermis in L3, but it was specifically localized to the hypodermis in adult worms. Western blots detected three protein bands in parasite lysates using anti-recombinant Oos-ANXL-2.1 antibody. Integrated optical density for each of the 3 Oos-ANXL-2s or the total Oos-ANXL-2s detected by Western blots (P < 0.05) was higher in adult worms than in L3 or L4. The results indicate that the production of Oos-ANXL-2s is developmentally regulated and most abundant in the adult worm. This rather large family of proteins could be a potential vaccine target against O. ostertagi infection and warrants further investigation.

Spatial distribution of mast cells around vessels and glands in human gastric carcinoma.

The spatial distribution of mast cells inside the tumor stroma has been little investigated. In this study, we have evaluated tumor mast cells (MCs) distribution in gastric cancer through the analysis of the morphological features of the spatial patterns generated by these cells, including size, shape, and architecture of the cell pattern. The pattern of distribution of tryptase- and chymase-positive MCs around the blood vessels and gastric glands in human gastric adenocarcinoma samples was investigated by immunohistochemical techniques and by introducing a quantitative approach to characterize the spatial distribution of MCs. In human gastric cancer, both chymase-positive MC and vessels exhibited significant deviations from randomness for what it concerns their spatial relationship with gastric parenchyma. As indicated by cell-to-gland distances shorter than expected by chance, in grade II samples a preferential localization of chymase-positive MC near the gastric glands was observed. Interestingly, the same type of spatial association was exhibited by vessels in grade IV samples, where vessel-to-gland distances shorter than expected by chance were observed. These two findings allow to speculate about a sequence of events in which a subpopulation of MC is first recruited around gastric parenchyma to drive the subsequent development of a vascular support to the tissue.

Sexual dimorphism in histological structure of normal rat stomach / Dimorfismo sexual en la estructura histológica del estómago normal de la rata

Fifty male and fifty female Spargue-Dawley rats were randomly chosen and used to study the sexual dimorphisms of stomachic histological structures. The rat stomach consisted of the nonglandular part and the glandular part. The gender differences of the nonglandular part existed in the thicknesses of the stratified squamous epithelium and the longitudinal muscle. These findings revealed that the male rat stomach may storage more foods than the female. The gastric glands occupied all the lamina propria in the glandular part. The thicknesses of the gastric glands of the female and male rat were 525.0 ± 95.9 µm and 472.0 ± 158.7 µm respectively, and the difference was very significant (p<0.01). The gastric glands could be divided to two layers in the HE stain, i.e. the luminal and the basal layers. The thicknesses of the luminal layer of the female and male rat were 289.7 ± 95.9 µm and 300.0 ± 120.7 µm respectively, and the difference was insignificant (p>0.05). On the contrary, the thicknesses of the basal layer and the three muscle layers in the female glandular part were all thicker than those in male, and the differences were very significant (P<0.01). These findings indicated that the female rat stomachs may have a more powerful digestive ability than the male ones. The nucleus-glandular index of the gastric gland of the normal female and male rat were 0.19 ± 0.05 and 0.18 ± 0.04 respectively, and the difference was insignificant (p>0.05).

Se seleccionaron al azar 100 ratas Sprague-Dawley, 50 de sexo masculino y 50 de sexo femenino, para estudiar los dimorfismos sexuales de las estructuras histológicas del estómago. El estómago de la rata consiste de una parte no glandular y de una parte glandular. Existen diferencias de género en la parte no glandular en relación al espesor del epitelio escamoso estratificado y del músculo longitudinal. Estos hallazgos revelaron que el estómago de las ratas masculinas puede almacenar más alimentos que las hembras. Las glándulas gástricas ocuparon toda la lámina propia de la parte glandular. Los espesores de las glándulas gástricas de la rata hembra y macho fueron 525,0±95,9 mm y 472,0±158,7 mm, respectivamente, y la diferencia fue muy significativa (p <0,01). En la tinción de Hematoxilina-Eosina (H-E) se visualiza la división de las glándulas gástricas en dos capas, es decir, en las capas luminal y basal. Los espesores de la capa luminal de la rata hembra y macho fueron 289,7±95,9 mm y 300,0±120,7 mm, respectivamente, y la diferencia fue no significativa (p> 0,05). Por el contrario, los espesores de la capa basal y las tres capas musculares en la parte glandular fueron más gruesos en las ratas hembras y las diferencias fueron muy significativas (p <0,01). Estos hallazgos indicaron que los estómagos femeninos de rata pueden tener una capacidad digestiva más potente que los masculinos. El índice núcleo-glandular de la glándula gástrica de la rata normal femenina y masculina fue 0,19±0,05 y 0,18±0,04 respectivamente, y la diferencia fue no significativa (p> 0,05).

Analysis of the Distribution of Mucins in Adult Human Gastric Mucosa and Its Functional Significance.

INTRODUCTION: Mucins are complex composition of carbohydrates seen in the epithelial cells lining the gastrointestinal tract (GIT). Normal distribution of such mucins in different part of the GIT and its alteration in various inflammatory, benign and malignant lesions of GIT has aroused interest in the field of histochemistry. AIM: By applying variety of histochemical techniques an attempt has been made to draw a map of mucin secretion by the different epithelial cell types in different parts of the stomach. MATERIALS AND METHODS: Fifty samples were taken each from different parts of the stomach like fundus, body and pylorus, from dissected fresh specimens (total of 150 specimens). Tissue samples were subjected for routine process and studied for histological and different histochemical staining. RESULTS: Mucin pattern in adult predominantly secretes neutral mucosubstances. Surface epithelium shows predominant neutral mucin while cardiac and gastric glands with foveolar cells show moderate amount. Sialomucin is present in a few cells of the surface epithelium, foveolar cells and in most of the mucous neck cells. Small amount of sialomucin and sulphomucin are found in surface epithelial foveolar cells while traces of sulphomucin are found in deep foveolar cells. Mucous neck cells secrete both sulphomucin and sialomucin. CONCLUSION: Normal gastric mucosa adjacent to gastric ulcers and malignant tumours of stomach secretes mucins which differ histochemically and biochemically from that of normal. Early recognition of such changes could be useful in recognizing the different type of carcinomas and their prognosis.

GLP-1 receptor is expressed in human stomach mucosa: analysis of its cellular association and distribution within gastric glands.

The stomach is a target organ of the incretin hormone glucagon-like peptide-1 (GLP-1). However, the cellular expression and glandular distribution of its receptor (GLP-1R) in human gastric mucosa are not known. We determined the expression of GLP-1R in different regions of human stomach mucosa and its specific cellular association and distribution within gastric glands. Tissue samples from stomach body and antrum were obtained from 20 patients during routine esophagogastroduodenoscopy. mRNA encoding GLP-1R protein expression was evaluated by RT-PCR. Determination of cell types bearing GLP-1R, their localization, and their frequency in gastric glands in different gastric regions were estimated by immunohistochemical morphological analysis. Levels of GLP-1R mRNA were similar in body and antrum. GLP-1R immunoreactivity was found throughout the gastric mucosa in various types of glandular cells. The highest frequency of GLP-1R immunoreactive cells was found in the neck area of the principal glands in cells morphologically identified as parietal cells. GLP-1R immunostaining was also found on enteroendocrine-like cells in the pyloric glands. This study provides the first description of GLP-1R expression in human gastric glands and its specific cellular association. Our data suggest that GLP-1 may act directly on the gastric mucosa to modulate its complex functions.