Effects of Retinoic Acid,Triiodothyronine and Hydrocortisone on Mucin and Lysozyme Expression in Cultured Human Middle Ear Epithelial Cells

Mucous hypersecretion is a major complication of otitis media and can prolong the disease course and increase morbidity. Mucin, a major component of mucus, is a macromolecular complex of glycoprotein and makes mucus viscous. Lysozyme is a secretory element of the middle ear mucosa, which has a non-specific and innate antibacterial function. We attempted to identify factors that regulate these secretory products and their morphological phenotype using cultured human middle ear epithelial cells. Cellular differentiation was induced by creating an air-liquid interface on culture day 9 in serum-free conditioned media. Omission of retinoic acid (RA) caused decrease in the secretion of mucin and lysozyme, and in the cellular expression of MUC 2, MUC 5AC and MUC 5B mRNA. In contrast, removal of triiodothyronine (T3) caused an increase in the secretion of mucin and the level of MUC5AC mRNA. When hydrocortisone (HC) was removed from the media, the secretion of mucin was decreased without an apparent change of message level. The expression of MUC 1 mRNA was not changed by the respective deficiency of RA, T3 or HC. The effect of T3 or HC on lysozyme was not significant. This study shows that RA, T3 and HC influence the morphological phenotype and the secretory function of mucin and lysozyme in cultured human middle ear epithelial cells. This culture system can serve as an in vitro model for study of the regulation of various cellular secretions in human middle ear epithelium.     

Ciliary and Secretory Differentiation of Normal Human Middle Ear Epithelial Cells

Recent technical advances now permit the serial culture of normal human middle ear epithelial (NHMEE) cells. However, the ciliary differentiation of these cells has not been achieved. The purpose of this study was to establish a culture system in order to differentiate serially cultured NHMEE cells into ciliated cells. If ciliated cells developed, the percentages of ciliated cells and secretory cells were measured throughout the duration of culture. We also examined the levels of mucin and lysozyme secretion and their mRNAs in a time-dependent manner. Human middle ear mucosa with a normal appearance was harvested and serially cultured after enzymatic disaggregation. These cells were cultured in an air-liquid interface (ALI) culture system for 2, 7, 14, 21 and 28 days after confluence. Ciliogenesis usually began 16-18 days after confluence. The percentage of ciliated cells detected by means of immunohistochemical staining increased over time up to a maximum of 10.6% but the percentage of secretory cells remained stable at 40% throughout the duration of culture. By Day 14 after confluence, the amounts of mucin and lysozyme secretion, as measured by dot-blotting analysis, had increased significantly and then remained stable. The expression levels of mucin gene 5B ( MUC5B ), MUC8 and lysozyme increased with the duration of culture. MUC8 in particular showed a dramatic increase on Day 28 after confluence. In contrast, the level of MUC5AC mRNA peaked on Day 14 after confluence, and then decreased. In conclusion, ciliary differentiation of NHMEE cells can be induced using an ALI culture system. Our study also suggests that secretory function develops earlier than ciliogenesis, and that the expressions of MUC5B and MUC8 mRNAs increase as a function of differentiation.     

Differentiated adenocarcinoma with a gastric phenotype in the stomach: difficulties in clinical and pathological diagnoses

Differentiated-type adenocarcinoma with gastric phenotype of the stomach is rare and is difficult to diagnose both clinically and pathologically. We report a case of differentiated-type adenocarcinoma with a gastric phenotype in the stomach. A 60-year-old Japanese female was referred to our hospital with gastric cancer. A barium meal examination and esophagogastroduodenoscopy revealed a granular elevated lesion in the lower body near the lesser curvature and a depressed lesion on the antrum. A biopsy specimen showed benign atrophic mucosa in a granulated lesion and moderately differentiated adenocarcinoma in the depressed lesion. The patient underwent laparoscopy-assisted distal gastrectomy with lymph node dissection. The postoperative course was uneventful. Histological examination of the resected tissue confirmed well-differentiated adenocarcinoma in the granulated lesion and moderately differentiated adenocarcinoma in the depressed lesion, without lymph node metastasis. Both lesions were confined to the mucosa. Since mucin immunohistochemistry revealed MUC5AC-positive staining in the granulated lesion, the final diagnosis was differentiated-type adenocarcinoma with gastric phenotype in the stomach. Despite the high malignant potential, the clinical and pathological diagnoses of gastric-type differentiated adenocarcinoma are often difficult. Mucin immunohistochemistry together with hematoxylin and eosin (HE) staining may be helpful in the pathological diagnosis of this rare disease.     

Invasive ductal carcinoma of the pancreas showing exophytic growth

BACKGROUND:Invasive pancreatic carcinoma generally appears as poorly defined mass reflecting the infiltrative growth.We aimed to identify the histological and immunohistochemical features in a rare case of pancreatic carcinoma showing exophytic growth. METHODS:A 67-year-old woman presented with a mass of 5.0 cm in diameter in the pancreatic head.Preoperative computed tomography revealed a well-demarcated, primarily solid mass with a central low-density area. Magnetic resonance cholangiopancreatography revea...     

Gallbladder Inflammation is Associated with Increase in Mucin Expression and Pigmented Stone Formation

Mucin is a high molecular weight glycoprotein that plays an important role in protecting the gallbladder epithelium from the detergent effect of bile. However, it also participates in gallstone formation. There is little information about a possible relationship between gallbladder inflammation and mucin expression or gallbladder stones’ characteristics. The aims of this study were to investigate stone characteristics and patterns of mucin expression in the gallbladder epithelium and bile of gallstone patients, in relation to inflammation. Gallbladder bile and tissue samples from 21 patients were obtained at surgery. Mucin content was evaluated by gel filtration on a Sepharose CL-4B column. Dot blot for bile mucin apoproteins and immunohistochemistry staining for gallbladder mucosal mucin apoproteins were performed with antibodies to MUC2, MUC3, MUC5AC, MUC5B and MUC6. Staining intensity score (0–3) was used for assessment of antigen expression and the level of inflammation. Gallstone cholesterol content was determined in 16 patients. MUC 5AC and MUC 5B were demonstrated in 95.4 and 100% of gallbladder bile samples, respectively. Immunohistochemistry staining with antibodies to MUC 2, MUC 3, MUC 5AC, MUC 5B and MUC 6 were positive in 0, 100, 85.7, 100 and 95.4% of the gallbladder mucosal samples, respectively. Pigmented brown stones were associated with a higher level of gallbladder inflammation. Mucin species expressed in gallbladder epithelium are MUC3, MUC5AC, MUC5B and MUC6. MUC5AC and MUC5B are secreted into bile. Inflammation of the gallbladder is accompanied by a higher level of MUC5AC expression and is associated with pigmented brown stones.     

Duodenal adenoma with production of massive mucus: report of a case with emphasis on US findings

Duodenal adenoma with massive mucus production is very rare. We report such a case. Ultrasonography (US) showed the presence of massive mucus, and contrast- enhanced US revealed the thickened wall to be homogeneously enhanced, suggesting that the lesion was composed of the same pathology. The US results were confirmed histologically by endoscopically guided biopsy. Thus, contrast-enhanced US helps determine the biopsy point and determine good diagnostic strategies.     

Muc2-deficient mice spontaneously develop colitis, indicating that MUC2 is critical for colonic protection

BACKGROUND & AIMS: Expression of mucin MUC2, the structural component of the colonic mucus layer, is lowered in inflammatory bowel disease. Our aim was to obtain insight in the role of Muc2 in epithelial protection. METHODS: Muc2 knockout (Muc2(-/-)) and Muc2 heterozygous (Muc2(+/-)) mice were characterized and challenged by a colitis-inducing agent, dextran sulfate sodium (DSS). We monitored clinical symptoms, intestinal morphology, and differences in intestine-specific protein and messenger RNA levels. RESULTS: The Muc2(-/-) mice showed clinical signs of colitis (as of 5 weeks), aggravating as the mice aged. Microscopic analysis of the colon of Muc2(-/-) mice showed mucosal thickening, increased proliferation, and superficial erosions. Colonic goblet cells in the Muc2(-/-) mice were negative for Muc2, but trefoil factor 3 was still detectable. In Muc2(-/-) mice, transient de novo expression of Muc6 messenger RNA was observed in the distal colon. On day 2 of DSS treatment, the histologic damage was more severe in Muc2(+/-) versus wild-type (Muc2(+/+)) mice, but the disease activity index was not yet different. By day 7, the disease activity index and histologic score were significantly elevated in Muc2(+/-) versus Muc2(+/+) mice. The disease activity index of the Muc2(-/-) mice was higher (versus both Muc2(+/+) and Muc2(+/-) mice) throughout DSS treatment. The histologic damage in the DSS-treated Muc2(-/-) mice was different compared with Muc2(+/+) and Muc2(+/-) mice, with many crypt abscesses instead of mucosal ulcerations. CONCLUSIONS: This study shows that Muc2 deficiency leads to inflammation of the colon and contributes to the onset and perpetuation of experimental colitis.     

黏蛋白在胃癌的诊断和预后评估中的作用

黏蛋白是由特殊的上皮细胞分泌的大分子量糖蛋白。多项研究显示黏蛋白在不同胃黏膜病变尤其在胃腺癌的不同类型中存在不同的表达:MUC1、MUC5AC、MUC6在正常胃黏膜中呈强阳性表达而MUC2则不表达。在正常胃黏膜向肠上皮化生、胃癌演进过程中,MUC1、MUC5AC、MUC6表达呈下调趋势而MUC2表达上调。此文就胃腺癌的不同类型及其发展,黏蛋白在不同胃黏膜病变中的表达及其在胃腺癌的诊断和预后评估中的作用等做一概述。     

Time trends for small gastric cancer in Japan

Background. Gastric cancer rates in Japan have been declining since the 1970s. The rate of differentiated carcinomas has decreased and that of undifferentiated carcinomas has increased. However, little is known about the time trends of small gastric cancer. The aim of this study was to investigate the trends of small gastric cancer over time in Japan. Methods. We reviewed cases of small gastric cancer (less than 20 mm in diameter) in two groups of patients who entered the age range of 55-to-67 years 14 years apart: patients in cohort 1 (n = 66) were born between 1899 and 1912, and those in cohort 2 (n = 66) were born between 1926 and 1936. Between-group comparisons were made for macroscopic, microscopic, and histochemical findings. Mucin histochemical analysis was used to investigate gastric and nongastric phenotypes. Helicobacter pylori was also investigated by immunohistochemistry. Results. There were significant decreases in the incidence of elevated carcinoma (20% in cohort 1 vs 6% in cohort 2; P < 0.05) and papillary adenocarcinoma (11% vs 2%; P < 0.05). The incidence of flat carcinomas was significantly increased (3% vs 15%; P < 0.05). The incidence of tumors surrounded by fundic gland mucosa increased (20% vs 29%), whereas that of tumors surrounded by intestinal metaplastic mucosa decreased (52% vs 41%). The rate of H. pylori infection in mucosa surrounding tumors was the same in both groups (35%). The incidence of tubular adenocarcinoma with gastric-type mucin was higher in cohort 2 (64%) than in cohort 1 (51%). Conclusion. The rate of tubular adenocarcinomas containing gastric type mucin has increased over time. These tumors had a tendency to develop in the fundic gland mucosa and to show less intestinal metaplasia. The H. pylori infection rate was unrelated to this time trend. In advanced gastric cancer, the differentiated carcinoma rate has decreased; however, in small gastric cancer, the rate of tubular adenocarcinoma containing gastric type mucin has increased. This suggests that tubular adenocarcinoma with gastric type mucin changes into poorly differentiated adenocarcinoma as tumors grow to advanced stages. Received: April 24, 2000 / Accepted: August 1, 2000     

胃肠道印戒细胞癌超微结构分型

通过对３８例胃肠道印戒细胞癌进行超微细胞结构观察，发现印戒细胞癌可有三种类型，即粘液型、微囊型和糖原型。结合粘液组化染色，作者对印戒细胞癌的细胞起源以及癌细胞不同形态表现的原因和意义进行了探讨，认为印戒细胞癌起源于具有多潜能分化的干细胞，癌细胞超微结构形态特征的变化是其畸形分化或功能代谢不同的具体表现。