Scanning electron microscopy in gastric adenocarcinoma and intestinal metaplasia

In recent years scanning electron microscopy has been used in gastric biopsy studies, contributing to better recognition of intestinal metaplasia and carcinoma, as a complement to light and transmission electron microscopy. During the second half of 1983, 53 cases of gastric carcinoma were diagnosed at the Department of Pathology of Hospital Mexico, of which six were studied ultrastructurally. A pattern similar to that of intestinal epithelium was found in cases of intestinal metaplasia. Well differentiated adenocarcinomas showed marked tumor cell proliferation with irregular "projections". In poorly differentiated carcinomas, changes were limited to areas where tumor cells invaded the epithelial surface. In summary, scanning electron microscopy is of great help in research and diagnosis of pathologic changes occurring in mucosal surfaces.     

A method for the quantitation of intestinal metaplasia of the stomach by morphometry

A novel method to quantitate the extent of intestinal metaplasia in gastrectomy specimens is presented. Morphometric measurements of histochemically labeled mucin-producing goblet cells were done in three selected gastrectomies (one having a peptic ulcer, one with adenocarcinoma of the intestinal type, and one with adenocarcinoma of the diffuse type). The sectioning of the gastrectomy specimens was standardized. The results indicated that the intestinal metaplasia was significantly higher in the specimen with adenocarcinoma of the intestinal type (as compared to the other two specimens), both along the lesser and greater curvatures as well as in the fundic area. These quantitative results confirm nonquantitative reports based on subjective visual impressions. This quantitative histochemical method for measuring the actual length as well as the topographical distribution of intestinal metaplasia in resected stomachs will be used in future studies of intestinal metaplasia with the aim of disclosing possible differences among populations with disparate incidences of gastric carcinoma.     

The fine structure of atypical ciliated cells in the human gastric epithelium

Gastric mucosa obtained from the body and pyloric portions of the human stomach were observed by light and transmission electron microscopy. Ciliated cells were found in two of 18 subjects examined, one patient with gastric ulcer and the other one with gastric adenocarcinoma. The ciliated cells were found in epithelia at sites away from the main lesions. The tissues containing ciliated cells showed intestinal metaplasia combined with mild chronic gastritis in both cases. The epithelial layer facing the gastric lumen was composed of columnar cells with numerous uniform microvilli and goblet cells. This epithelium extended to the superficial parts of the tubules surrounded by the lamina propria. The deeper portions of the tubules were composed of mucous secretory, endocrine, and rarely ciliated cells. These ciliated cells were provided with numerous cilia the numbers of which varied considerably from cell to cell. This was in contrast to the primary cilium which is usually single. The central part of the apical cell membrane was sometimes concave in the area from where cilia tended to arise. It was also observed that numerous basal bodies as well as mucus-like granules were contained in the same cell. The axonemal pattern was different from that of ordinary cilia and showed 9 + 0 and 8 + 1 patterns. In longitudinal sections it was found that one peripheral doublet was displaced to the center of the axoneme as it left the basal body.     

胃粘膜肠上皮化生SC3A的免疫组织化学研究

应用免疫组织化学ＡＢＣ方法等检测６２ 例胃良、恶性病变伴肠化组织中单克隆抗体ＳＣ３Ａ的表达及意义。结果： 癌旁肠化硫酸粘液阳性率明显较良性病变伴肠化高; 硫酸粘液阳性组肠化ＳＣ３Ａ阳性率明显高于硫酸粘液阴性组; 而且ＳＣ３Ａ 阳性率在酸性粘液阳性组胃癌明显高于酸性粘液阴性组; 硫酸粘液阳性组胃癌明显高于硫酸粘液阴性组。提示结肠型肠化可能与肠型胃癌的发生有一定关系     

Morphochemical analysis of mucosubstances in some epithelial tissues of the eel (Anguilla japonica).

In attempts to gain insight into the nature of mucosubstances in the eel epithelial tissues, the epidermis and epithelia lining the gill and intestine of the fish have been reacted for a series of light microscopic stainings of mucosaccharide and protein histochemistry under normal and experimental conditions. The present morphochemical analyses indicate that (1) the mucosubstances of the epidermis are found within two well differentiated cell types, goblet and clavate cells which elaborate a neuraminic acid containing mucosaccharide with vicinal hydroxyl, sulfate and carboxyl groupings and a glycoprotein respectively and (2) the mucosubstances of the gill and intestinal epithelia are found within goblet cells which elaborate a mucosaccharide with histochemical properties comparable to those of mucosaccharide within the epidermal goblet cells. The histochemical characteristics of all these mucosubstances have been briefly discussed in relation to the activities of the epithelial tissues in the eel.     

Functional Role of Metaplastic Paneth Cell Defensins in Helicobacter pylori-Infected Stomach

Background and Aims:  Chronic gastritis is caused by Helicobacter pylori infection, and gastritis is classified as inflammation, atrophy, and intestinal metaplasia. Detailed pathologic studies have shown that H. pylori settles on the surface of gastric mucosa, and that it is eliminated from metaplastic mucosa. However, its mechanism of natural protection is not well known.
Methods:  Antimicrobial human enteric defensin expression was determined in the RNA and protein levels. Recombinant enteric defensins were produced with a bacterial expression system and their anti- H. pylori activities were assessed by bactericidal assay.
Results:  Human enteric defensin (HD)-5 and HD-6 were detected in Paneth cells, which are observed in the gastric metaplastic mucosa as well as small intestinal epithelia. HD-5 protein was coexpressed with trypsin, which is considered to be an activating enzyme of HD-5. Less H. pylori was observed in the intestinal metaplasia with HD-5 expressing Paneth cells. The recombinant defensins showed killing activity against H. pylori at a low concentration in vitro.
Conclusions:  The human defensins that are expressed in the metaplastic Paneth cells eliminate H. pylori . Metaplastic change may be a purposive development of the human stomach.     

Acid, bile, and CDX: the ABCs of making Barrett's metaplasia

Barrett's esophagus, a squamous-to-columnar cell metaplasia that develops as a result of chronic gastroesophageal reflux disease (GERD), is a risk factor for esophageal adenocarcinoma. The molecular events underlying the pathogenesis of Barrett's metaplasia are poorly understood, but recent studies suggest that interactions among developmental signaling pathways, morphogenetic factors, and Caudal homeobox (Cdx) genes play key roles. Strong expression of Cdx genes normally is found in the intestine but not in the esophagus and stomach. When mice are genetically engineered so that their gastric cells express Cdx, the stomach develops a metaplastic, intestinal-type epithelium similar to that of Barrett's esophagus. Exposure to acid and bile has been shown to activate the Cdx promoter in certain esophageal cell lines, and Cdx expression has been found in inflamed esophageal squamous epithelium and in the specialized intestinal metaplasia of Barrett's esophagus. Barrett's metaplasia must be sustained by stem cells, which might be identified by putative, intestinal stem cell markers like leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) and doublecortin and CaM kinase-like-1 (DCAMKL-1). Emerging concepts in tumor biology suggest that Barrett's cancers may develop from growth-promoting mutations in metaplastic stem cells or their progenitor cell progeny. This report reviews the roles of developmental signaling pathways and the Cdx genes in the development of normal gut epithelia and the potential mechanisms whereby GERD may induce the esophageal expression of Cdx genes and other morphogenetic factors that mediate the development of Barrett's metaplasia. The role of stem cells in the development of metaplasia and in carcinogenesis and the potential for therapies directed at those stem cells also is addressed.     

Improved method for mapping gastric intestinal metaplasia using selective histochemical morphometry

A gastrectomy specimen containing two tubular adenomas from a 67-year-old woman was mapped by an improved method using selective histochemical staining. The specimen was divided into 83 blocks measuring 4.0 cm x 0.5 cm. Sections from the blocks were stained with alcian blue (pH 2.5) to detect mucin. Alcian blue-stained fields were easily identified and measured with the aid of a MOP 30 interactive digital image analyzer. The total area of gastric mucosa analyzed in the 83 sections measured 3,270.9 sq mm while the area occupied by alcian blue-stained goblet cells measured 755.9 sq mm (23.1% of the total area). Intestinal metaplasia was present in 46 of 83 blocks. Both the mean size of alcian blue-positive fields per section as well as the number of alcian blue-positive fields per section were significantly larger in the antral zone I and the intermediate zone II than in the fundal zones III, IV and V. The highest proportion of gastric mucosa with intestinal metaplasia was not found around the two gastric adenomas, but elsewhere. There was no significant difference in the proportion of intestinal metaplasia between the greater and lesser curvatures, further challenging the belief that intestinal metaplasia is always greatest along the lesser curvature. The method described will permit future studies of the possible association between intestinal metaplasia and dysplasias and adenocarcinomas of the stomach.     

慢性胃炎肠化生CD_(44)、CD_(44V6)及Cyclin D_1、Cyclin E的表达和意义

目的探讨慢性胃炎胃粘膜肠化生CD44、CD44V6及cyclin D1、Cyclin E表达的意义。方法利用免疫细胞化学技术对39例伴有肠化生的慢性胃炎和5例正常人胃窦粘膜的活检组织进行检查。结果正常人胃窦粘膜上皮,腺上皮对CD44、CD44V6、Cyclin D1和Cyclin E均为阴性,但在有神经内分泌样细胞的粘膜,CD44V6和cyclin D1为阳性。慢性胃炎肠化生区和不典型增生区除CD44为阴性外,CD44V6、cyclin D1和cyclin E均呈现不同的阳性反应,但未见有阳性的神经内分泌样细胞。间质细胞大都呈阳性反应。结论CD44V6、cyclin D1和cyclin E可能是胃癌前状态的早期事件,而CD44可能为胃癌晚期的标志物。     

Conversion of gastric mucosa to intestinal metaplasia in Cdx2-expressing transgenic mice

Gastric intestinal metaplasia occurs as a pathological condition in the gastric mucosa. To clarify how an intestine-specific homeobox gene, Cdx2, affects the morphogenesis of gastric mucosa, we generated transgenic mice expressing Cdx2 in parietal cells. Until Day 18 after birth, the number of parietal cells inthegastric mucosa of transgenic mice was the same as for their normal littermates. However, at Day 19, we detected several glands in which parietal cells disappeared and the proliferating zone moved from the isthmus to the base of the glands. Thereafter, parietal cells decreased gradually and disappeared at Day 37. All of the gastric mucosal cells, except for enterochromaffin-like (ECL) cells, were completely replaced by intestinal metaplasia, consisting of goblet cells, enteroendocrine cells, and absorptive cells expressing alkaline phosphatase. Pseudopyloric gland metaplasia was also formed. The transgenic mouse is a very useful model for clarifying physiological differentiation of gastric and intestinal cell lineages and analyzing the molecular events from intestinal metaplasia to adenocarcinoma.     

Effect of Helicobacter pylori infection and eradication on gastric epithelial cell proliferation and apoptosis.

OBJECTIVES: the effect of Helicobacter pylori infection on gastric epithelial cell proliferation and apoptosis is still controversial. Our aim was to evaluate the effect of H. pylori infection on cell kinetic parameters in normal gastric epithelium, gastritis with/without intestinal metaplasia and gastric cancer. PATIENTS AND METHODS: antral biopsies were taken from 121 patients (61 women, 60 men, mean age 58.5+/-14.3 years of age) who underwent routine gastroscopy for upper gastrointestinal symptoms. Sections were scored for normal epithelia (n=15), gastritis without intestinal metaplasia (n=74), gastritis with intestinal metaplasia (n=24), and gastric adenocarcinoma (n=8). Fifty-two patients had H. pylori positive gastritis, and success of H. pylori eradication therapy was controlled in 12 cases, all with intestinal metaplasia. To characterize cell proliferation and assess apoptosis, immunohistochemistry [Proliferating Cell Nuclear Antigen (PCNA)], histochemistry [Argyrophil Nucleolar Organizer Regions (AgNOR)], and terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridinetriphosphate (dUTP) nick end-labeling (TUNEL) were used, respectively. RESULTS: both cell proliferation and apoptosis is was higher in chronic gastritis when compared with normal epithelia, but neither PCNA LI (54.79+/-19.1 vs. 53.20+/-20.7) nor AgNOR counts (291.43+/-44.3 vs. 277.8+/-57.54) were different in H. pylori positive versus negative chronic gastritis. A significant positive correlation (P<0.05) was found in this group between PCNA and AgNOR techniques. Apoptosis was significantly higher (P<0.05) in H. pylori positive cases only when intestinal metaplasia was not present. Cell proliferation in intestinal metaplasia decreased to the activity of normal epithelium after successful eradication of H. pylori but remained high if eradication therapy failed. CONCLUSIONS: epithelial cell proliferation does not depend on H. pylori status in chronic gastritis. H. pylori increases apoptosis only in the absence of intestinal metaplasia.     

胃癌及癌旁组织癌胚抗原分布的免疫电镜观察

应用免疫电镜技术对１４例胃癌手术切除标本进行胃癌及癌旁组织中癌胚抗原（ＣＥＡ）超微结构水平分布的定位观察。结果表明,癌旁正常胃粘膜上皮细胞ＣＥＡ含量很少,仅在表面微绒毛见到微弱的ＣＥＡ分布;肠化上皮细胞ＣＥＡ主要分布在吸收细胞的微绒毛及杯状细胞粘液颗粒之间;而胃癌细胞ＣＥＡ除分布腔面微绒毛外,尚分布细胞侧面,基底面或整个胞膜,还见于胞浆内膜结构中。ＣＥＡ在胃癌细胞与正常胃粘膜上皮及肠化上皮分布上的差异说明表面膜成份极性的丧失是上皮性肿瘤细胞的特征之一。ＣＥＡ在胃癌细胞的分布异常可能导致恶性细胞某些生物学行为的变化。     

Terminal alpha1,4-linked N-acetylglucosamine in Helicobacter pylori-associated intestinal metaplasia of the human stomach and gastric carcinoma cell lines.

Helicobacter pylori (Hp) infection is associated with the development of gastric lesions including gastritis, intestinal metaplasia (IM), and gastric carcinoma. In humans, Hp is found almost exclusively in the foveolar epithelium of the gastric mucosa and rarely colonizes the deeper portions where mucous cells of the glands produce mucins with terminal alpha1,4-GlcNAc O-glycans. This structure exerts antimicrobial activity against Hp. The development of IM in the stomach is characterized by Hp clearance from the metaplastic glands and by major alterations in the expression of mucins and mucin-carbohydrates. The present work evaluated whether terminal alpha1,4-GlcNAc and sialyl-Tn antigen are implicated in the process of Hp clearance from metaplastic glands by analyzing the expression of these antigens in different types of IM-complete (n=12) and incomplete (n=8)-and in gastric cell lines. Terminal alpha1,4-GlcNAc was not detected in IM except in a single foci of one case, indicating that this structure is not implicated in the clearance of Hp from IM, in contrast to what is observed in normal gastric mucosa. None of the gastric carcinoma cell lines studied showed terminal alpha1,4-GlcNAc, suggesting that they do not display a gastric gland mucous cell phenotype and therefore are useful models for in vitro Hp studies. Finally, sialyl-Tn antigen colocalizes with MUC2 mucin and is present in all cases of complete and incomplete IM, suggesting that either or both can be implicated in Hp clearance from IM.     

Ultrastructural localization of alkaline phosphatase activity in the intestine of developing Rana catesbeiana.

Alkaline phosphatase activity has been localized at the light and electron microscopic levels in the intestine of developing frog, Rana catesbeiana. The intensity of the histochemical reactivity decreases along the intestinal tract. The intracellular localization of the enzymatic activity shows continuous series of organelles loaded with the reaction product from the Golgi zones to the brush border. These results are in agreement with the biochemical observations made on the same material.     

胃癌癌旁肠化上皮酶组织化学研究

本文应用酶组化方法对６０例胃癌癌旁粘膜中４７例肠化上皮（７８．３％）的破性磷酸酶（ＡＬＰ）、酸性磷酸酶（ＡＣＰ）、胞嘧啶单核苷酸酶（ＣＭＰ）、葡萄糖－６－磷酸酶（Ｇ－６－ｐａｓｅ）、焦磷酸硫胺素酶（ＴＰＰａｓｅ）、５－核苷酸酶（ＳＮａｓｅ）、三磷酸腺苷酶（Ｍｇ２＋－ＡＴＰａｓｅ,Ｃａ２＋－ＡＴＰａｓｅ）和细胞色素氧化酶（ＣＣＯ）等九种细胞器标志酶进行了定位观察。结果发现肠化上皮吸收细胞上述酶活性均较强,且分布具有极性,杯状细胞酶反应较弱,主要位于细胞基底部。癌旁粘膜肠化阳性率为７８．３％,其中ＡＬＰ阳性的酶完全型肠化和ＡＬＰ阴性的酶不完全型肠化分别占５３．２％,４６．８％,两者出现率相近。酶完全型肠化ＡＬＰ阳性率在胃分化型癌及未分化型癌瘤旁分别占６９．２％和３３．３％。ＡＬＰ阳性率在胃分化型及未分化型癌组织内分别为３５．５％和０％。提示肠化上皮具有与肠上皮相似的代谢特征,酶完全型肠化和酶不完全型肠化可能是肠化的二种不同的形式,在致癌环境下,二者都有可能转变成癌,其中酶完全型肠化与分化型癌的关系较为密切。     

Deviated formation of intestinal glycocalyx in human stomach cancer cells. Another type of signet ring cell.

The process of glycocalyx formation by the trilaminar membrane was investigated at the subcellular level by use of cultivated cancer cells derived from a human stomach adenocarcinoma. Glycocalyx was apparently synthesized on the characteristic trilaminar membrane of Golgi-derived vesicles which gave rise to cytoplasmic vacuoles which, in turn, fused to form an intracytoplasmic cyst. Characteristic microvilli similar to those of intestinal epithelium extended from the membrane lining the intracytoplasmic cyst. These ultrastructural features agree with earlier histochemical findings in suggesting intestinal metaplasia in the origin of the gastric tumor. The morphologic features of the cancer cells clearly indicated that glycoprotein is first synthesized in the Golgi complex and fully formed mucoprotein then emerges as membrane-bound glycocalyx in the vesicles budding from the Golgi stacks. The glycocalyx layer is an integral part of the external leaflet of the characteristic trilaminar membrane. Abundant deposits of glycocalyx in the intracytoplasmic cyst constituted the ultrastructural basis for a distinctive type of signet ring cell that differed from mucous signet ring cells derived from goblet cells.     

Multidrug resistance gene and P-glycoprotein expression in gastric adenocarcinoma and precursor lesions

Overexpression of the Multiple Drug Resistance gene (MDR1) has been proposed as a major mechanism related to both intrinsic and acquired resistance to chemotherapeutic agents. The gene product is a membrane protein (P-glycoprotein), that acts as an energydependent drug efflux pump decreasing drug accumulation in resistant tumor cells. We have characterized MDR1 and P-Glycoprotein expression in human gastric adenocarcinoma and in precursor lesions. MDR1 mRNAs, analyzed by dot-blot technique, were detected in 9 of 10 non-tumoral gastric mucosae and in 8 of 10 gastric adenocarcinomas. Immunohistochemical analysis, using the MRK16 monoclonal antibody, revealed heterogeneous expression of P-Glycoprotein in individual cells. The P-Glycoprotein was found on the surface of cells of gastric areas with intestinal metaplasia subtype III. This type of intestinal metaplasia, also called “colonic metaplasia”, has been strongly associated with a high risk for the development of gastric cancer. The fact that the P-Glycoprotein was detected in this precursor lesion is consistent with the intestinal metaplasia dysplasia and carcinoma sequence proposed in the histogenesis of this tumor. The finding that P-Glycoprotein was heterogeneously expressed in malignant cells of some gastric adenocarcinomas also suggests that this transporter system probably contributes to primary and secondary multidrug resistance in this neoplasm.     

Multidrug resistance gene and P-glycoprotein expression in gastric adenocarcinoma and precursor lesions.

Overexpression of the Multiple Drug Resistance gene (MDR1) has been proposed as a major mechanism related to both intrinsic and acquired resistance to chemotherapeutic agents. The gene product is a membrane protein (P-glycoprotein), that acts as an energy-dependent drug efflux pump decreasing drug accumulation in resistant tumor cells. We have characterized MDR1 and P-Glycoprotein expression in human gastric adenocarcinoma and in precursor lesions. MDR1 mRNAs, analyzed by dot-blot technique, were detected in 9 of 10 non-tumoral gastric mucosae and in 8 of 10 gastric adenocarcinomas. Immunohistochemical analysis, using the MRK16 monoclonal antibody, revealed heterogeneous expression of P-Glycoprotein in individual cells. The P-Glycoprotein was found on the surface of cells of gastric areas with intestinal metaplasia subtype III. This type of intestinal metaplasia, also called "colonic metaplasia", has been strongly associated with a high risk for the development of gastric cancer. The fact that the P-Glycoprotein was detected in this precursor lesion is consistent with the intestinal metaplasia-dysplasia and carcinoma sequence proposed in the histogenesis of this tumour. The finding that P-Glycoprotein was heterogeneously expressed in malignant cells of some gastric adenocarcinomas also suggests that this transporter system probably contributes to primary and secondary multidrug resistance in this neoplasm.     

Characterization of metaplastic and heterotopic epithelia in the human gastrointestinal tract by the expression pattern of acyl-CoA synthetase 5

Metaplastic and heterotopic epithelia are frequently found in the human intestine. The recently cloned human acyl-CoA synthetase 5 (ACS5) is a key enzyme in providing cytosolic acyl-CoA thioesters. The aim of the study was to identify and to locate the expression of ACS5 in the gastric body and the small intestine with metaplasia or heterotopia by different methods. In the normal gastrointestinal tract, ACS5 was predominantly found in the villus epithelium of the small intestine, but not in the gastric mucosa. Of note, strong expression of ACS5 was also detectable in intestinal metaplasia of the stomach. Inversely, ACS5 expression could neither be detected in heterotopic gastric mucosa of the corpus type nor in gastric, pseudopyloric, or antral metaplasia of the small intestine. In conclusion, our data implicate that ACS5 is a suitable differentiating marker molecule in the gastrointestinal tract.