Claudin-3 and occludin tissue content in the glands of colonic mucosa with and without a fecal stream

Somatostatin alleviates diversion colitis after fecal-stream bypass colostomy surgeries in rats

BACKGROUND

Diversion colitis (DC) is a prevalent complication of colostomy characterized by intestinal inflammation. This study aimed to investigate the therapeutic potential of somatostatin (SST) in managing DC.

METHODS

After establishing a rat DC model, SST was administered via Mini Osmotic Pumps 2001W at a pumping rate of 1.0 μL/h. Various techniques, including hematoxylin and eosin staining, periodic acid-Schiff staining, immunofluorescence staining, and electron microscopy were employed to assess the effects of SST. Intestinal barrier functions were evaluated using Evans blue, enzyme-linked immunosorbent assay, and MacConkey agar.

RESULTS

After SST treatment, the significant weight loss and associated high mortality in the DC group were successfully mitigated. Upregulation of claudin-3 and claudin-4 restored mechanical barriers in colon epithelial tissue, whereas protection of goblet cells and stimulation of mucus secretion enhanced mucus barriers. SST effectively reduced leaky gut and alleviated systemic inflammation.

CONCLUSION

This study provides initial evidence supporting the efficacy of SST in the treatment of DC. It offers insights into the role of SST in DC by elucidating its ability to restore damaged intestinal barriers.

Mucin levels in glands of the colonic mucosa of rats with diversion colitis subjected to enemas containing sucralfate and n-acetylcysteine alone or in combination

PURPOSE

To evaluate the tissue content of neutral and acidic mucins, sulfomucins and sialomucins in colonic glands devoid of intestinal transit after enemas containing sucralfate and n-acetylcysteine alone or in combination.

METHODS

Sixty-four rats underwent intestinal transit bypass. A colonic segment was collected to compose the white group (without intervention). After derivation, the animals were divided into two groups according to whether enemas were performed daily for two or four weeks. Each group was subdivided into four subgroups according to the substance used: control group: saline 0.9%; sucralfate group (SCF): SCF 2 g/kg/day; n-acetylcysteine group (NAC): NAC 100 mg/kg/day; and SCF+NAC group: SCF 2 g/kg/day + NAC 100 mg/kg/day.Neutral and acidic mucins were stained by periodic acid-Schiff and alcian-blue techniques, respectively. The distinction between sulfomucins and sialomucin was made by the high alcian-blue iron diamine technique. The content of mucins in the colonic glands was measured by computerized morphometry. The inflammatory score was assessed using a validated scale. The results between the groups were compared by the Mann-Whitney's test, while the variation according to time by the Kruskal-Wallis' test (Dunn's post-test). A significance level of 5% was adopted.

RESULTS

There was reduction in the inflammatory score regardless of the application of isolated or associated substances. Intervention with SCF+NAC increased the content of all mucin subtypes regardless of intervention time.

CONCLUSIONS

The application of SCF+NAC reduced the inflammatory process of the colonic mucosa and increased the content of different types of mucins in the colonic glands of segments excluded from fecal transit.

Tissue Content and Pattern of Expression of Claudin-3 and Occludin in Normal and Neoplastic Tissues in Patients with Colorectal Cancer

BACKGROUND

Metastasis is the worst prognostic variable of patients with colorectal cancer (CRC). For the development of metastases, it is necessary that cancer cells detach from the primary tumor, migrate into the angiolymphatic system, and invade the tissue where they will develop. The breakdown of the tight junctions (TJs) plays an important role in colorectal metastatic tumors. Claudin-3 and occludin are the main component proteins of TJs.

AIM

To analyze the expression and tissue content of claudin-3 and occludin in normal and neoplastic tissues of patients with metastatic CRC.

METHODS

Fifty-seven consecutive patients with stage III and IV CRC were included. Fragments of neoplastic tissue were collected from the tumor margins, and samples of the normal tissue were collected from the same patient in a standardized distance of 10 cm from the cranial margin of the tumor. Immunohistochemistry technique was used to identify the tissue staining of claudin-3 and occludin. To measure the content of both proteins in cellular membranes of normal and cancer cells, a validated immunoscore was used.

RESULTS

Claudin-3 and occludin in normal tissues are in the apical and lateral membranes of cells, while in the neoplastic, in cytoplasm. The mean of the tissue content of claudin-3 in the normal tissue was 2.57 ± 0.16, while in the neoplastic tissue was 1.03 ± 0.13. The contents of occludin were 2.77 ± 0.1 in normal tissue, while in the neoplastic were 1.08 ± 0.14.

CONCLUSION

There is a reduction in the content of the claudin-3 and occludin in the cell membranes of the neoplastic tissue in patients with CRC.

The Pathology and Physiology of Ileostomy

An ileostomy is a surgery that is commonly performed to protect low pelvic anastomoses or prevent high-risk anastomotic leakages. However, various postoperative complications remain of major concern. After an ileostomy, the distal intestinal segment is left open for an extended period and is in a non-functional state. Consequently, the intestinal mucosa, smooth muscle, and microbiota undergo significant changes that are closely related to postoperative recovery and complications. A systematic description of these changes is necessary to understand the relationship among them and take more effective measures for postoperative intervention.

ENEMA DE SULCRALFATO PODE PREVENIR COLITE EM SEGMENTOS COLÔNICOS SEM TRÂNSITO FECAL?

RESUMO - RACIONAL: O estresse oxidativo é um dos principais mecanismos associados à ruptura dos mecanismos de defesa que formam a barreira epitelial cólica e reduz o conteúdo tecidual das proteínas claudina-3 e ocludina principais constituintes das junções de oclusão intercelulares. O sucralfato, possui atividade antioxidante e tem sido usado para tratar diferentes formas de colite. OBJETIVO: Mensurar o conteúdo tecidual de claudina-3 e ocludina da mucosa do cólon sem trânsito fecal, submetido à intervenção com sucralfato. MÉTODO: Trinta e seis ratos foram submetidos à colostomia do cólon esquerdo e fístula mucosa distal. Os animais foram divididos em dois grupos de acordo com a eutanásia ser realizada duas ou quatro semanas após a intervenção. Cada grupo foi dividido em três subgrupos de acordo com o tipo de intervenção realizada diariamente: solução salina isolada; sucralfato a 1 g/kg/dia ou sucralfato a 2g/kg/dia. A colite foi diagnosticada por análise histológica adotando escala de validação prévia. A expressão tecidual de ambas as proteínas foi identificada por imunoistoquímica. O conteúdo das proteínas foi quantificado por análise de imagem assistida por computador. RESULTADOS: O escore inflamatório foi maior nos segmentos cólicos sem trânsito fecal e os enemas com sucralfato reduziram o escore inflamatório nesses segmentos, principalmente nos animais submetidos à intervenção com sucralfato em maior concentração e por período mais longo de intervenção. Houve aumento no conteúdo tecidual das proteínas claudina-3 e ocludina, relacionado com a concentração de sucralfato. O conteúdo tecidual de ambas as proteínas não se modificou com a duração da intervenção. CONCLUSÃO: Enemas com sucralfato reduzem a inflamação e aumentam o conteúdo tecidual de claudina-3 e ocludina na mucosa cólica sem trânsito intestinal.

Characterization of a Novel Diarrheagenic Strain of Proteus mirabilis Associated With Food Poisoning in China

Proteus mirabilis is commonly considered to be an opportunistic pathogen causing urinary tract infections (UTIs) in humans. However, some strains of P. mirabilis were found to be associated with food poisoning outbreaks, with the pathogenic mechanism still unclear. In our study, we described a novel strain of P. mirabilis C02011 isolated from patients’ specimens in a food poisoning in China. In order to determine its gastrointestinal pathogenicity, experiments were performed to compare P. mirabilis B02005 strain (isolated from healthy people) and P. mirabilis American Type Culture Collection (ATCC) 29906 strain both in vitro [Caco-2 cells: bacterial adhesion and invasion assays, Giemsa staining, and transmission electron microscopy (TEM)] and in vivo [BALB/c mouse model: fecal character, colon injury, histological examination, immunochemistry, and western blotting (WB)]. According to the results, C02011 strain exhibited almost identical characteristics with B02005 strain in bacterial appearance and proliferation. In vitro, Caco-2 cells were infected with P. mirabilis C02011, B02005, and P. mirabilis ATCC 29906 strains. After that, Giemsa staining and TEM were used for observing the infection process of C02011 strain. Meanwhile, the adhesive abilities of different strains were rated as follows: P. mirabilis B02005 > P. mirabilis C02011 > P. mirabilis ATCC 29906 (P < 0.01). Invasive abilities of different strains were rated as follows: P. mirabilis C02011 > P. mirabilis B02005 > P. mirabilis ATCC 29906 (P < 0.01). In vivo, BALB/c mice were infected with P. mirabilis C02011 and B02005 strains. C02011 strain shows more virulence than B02005 strain in terms of the following indicators: (1) feces water content and fecal character; (2) colon length of mice; (3) histological examination on mouse intestine tissues; (4) ELISA for detecting TNF-α level in the colon; and (5) WB and immunohistochemistry (IHC) for detecting occludin protein expression in the colon. On the basis of these results, we firstly validated that the novel strain of P. mirabilis C02011 shows more gastrointestinal pathogenicity than the other strains isolated from a healthy individual. In addition, type IV secretion system (T4SS) was preliminarily confirmed to play an important role in the pathogenesis of diarrheal P. mirabilis isolated from the food poisoning incident.

Enemas with mesalazine increase the tissue contents of mucins in the colonic mucosa devoid of fecal stream

Purpose:

To evaluate the inflammatory reaction and measure the content of mucins, in the colonic mucosa without fecal stream submit to intervention with mesalazine.

Methods:

Twenty-four rats were submitted to a left colostomy and a distal mucous fistula and divided into two groups according to euthanasia to be performed two or four weeks. Each group was divided into two subgroups according daily application of enemas containing saline or mesalazine at 1.0 g/kg/day. Colitis was diagnosed by histological analysis and the inflammatory reaction by validated score. Acidic mucins and neutral mucins were determined with the alcian-blue and periodic acid of Schiff techniques, respectively. Sulfomucin and sialomucin were identified by high iron diamine-alcian blue technique. The tissue contents of mucins were quantified by computer-assisted image analysis. Mann-Whitney test was used to analyze the results establishing the level of significance of 5%.

Results:

Enemas with mesalazine in colonic segments without fecal stream decreased the inflammation score and increased the tissue content of all subtypes of mucins. The increase of tissue content of neutral, acid and sulfomucin was related to the time of intervention.

Conclusion:

Mesalazine enemas reduce the inflammatory process and preserve the content of mucins in colonic mucosa devoid of fecal stream.

Role of short-chain fatty acids in colonic inflammation, carcinogenesis, and mucosal protection and healing

Short-chain fatty acids (SCFAs), mainly acetate, propionate, and butyrate, produced by microbial fermentation of undigested food substances are believed to play a beneficial role in human gut health. Short-chain fatty acids influence colonic health through various mechanisms. In vitro and ex vivo studies show that SCFAs have anti-inflammatory and anticarcinogenic effects, play an important role in maintaining metabolic homeostasis in colonocytes, and protect colonocytes from external harm. Animal studies have found substantial positive effects of SCFAs or dietary fiber on colonic disease, but convincing evidence in humans is lacking. Most human intervention trials have been conducted in the context of inflammatory bowel disease. Only a limited number of those trials are of high quality, showing little or no favorable effect of SCFA treatment over placebo. Opportunities for future research include exploring the use of combination therapies with anti-inflammatory drugs, prebiotics, or probiotics; the use of prodrugs in the setting of carcinogenesis; or the direct application of SCFAs to improve mucosal healing after colonic surgery.

Claudin-3 and occludin content in the glands of colonic mucosa devoid from fecal stream submitted to topical intervention with oil extract of Curcuma longa

Purpose:

To evaluate the inflammatory intensity and measure the tissue content of the proteins claudin-3 and occludin in the colonic mucosa without fecal stream submit to intervention with curcumin.

Methods:

Thirty-six rats were submitted to a proximal colostomy and a distal mucous fistula and divided into two groups according to sacrifice to be performed two or four weeks. Each group was divided into three subgroups according daily application of enemas containing saline, curcumin at 50 mg/kg/day or 200 mg/kg/day. Colitis was diagnosed by histological analysis. Claudin-3 and occludin were determined by immunohistochemistry. The tissue content of claudin-3 and occludin were quantified by computer-assisted image analysis. Mann-Whitney, Student t and ANOVA tests were used to analyze the results establishing the level of significance of 5% for both (p<0.05).

Results:

Curcumin at both concentrations reduces the inflammation and preserves the tissue content of the proteins claudin-3 and occludin, which was related to the concentration used and to the time of the intervention.

Conclusion:

The application of enemas with curcumin reduces inflammation and preserves the tissue content of the proteins claudin-3 and occludin in the colonic mucosa devoid from the fecal stream.

Deviation of the Fecal Stream in Colonic Bowel Segments Results in Increased Numbers of Isolated Lymphoid Follicles in the Submucosal Compartment in a Novel Murine Model of Diversion Colitis

INTRODUCTION

Diversion colitis is a significant health problem due to its high incidence in patients with diverting enterostomy. This mucosal inflammation presents characteristic histopathological features allowing for the differentiation of this entity from other inflammatory bowel diseases. The pathophysiology of this disease remains ill-defined, in part due to the lack of appropriate animal models. The present study was performed in order to develop and characterize a murine model of diversion colitis.

METHODS

A diverting loop colostomy was performed in C57BL/6 mice either in the ascending colon or in the transverse colon. Animals were assessed for clinical and histopathological parameters during short-term and long-term survival.

RESULTS

Animals with a colostomy in the transverse colon showed a good long-term survival and developed a mild colitis in the bypassed bowel closely resembling the human pathology on a histopathological level.

CONCLUSION

This model is a promising tool to further elucidate the pathomechanism leading to impaired mucosal homeostasis in bypassed colonic segments. Moreover, the establishment of the model in the C57BL/6 background allows the combination of this colitis model with various transgenic mouse strains to investigate the effect of locally deregulated mucosal immunity on systemic immune homeostasis and to develop specific therapeutic strategies.

Interferon-gamma increased epithelial barrier function via upregulating claudin-7 expression in human submandibular gland duct epithelium

Tight junctions (TJs) are necessary for salivary gland function and may serve as indicators of salivary gland epithelial dysfunction. IgG4-related disease (IgG4-RD) is a newly recognized fibro-inflammatory condition which disrupts the TJ associated epithelial barrier. The salivary glands are one of the most frequently involved organs in IgG4-RD, however, changes of the TJ associated epithelial barrier in salivary gland duct epithelium is poorly understood. Here, we investigated the regulation and function of TJs in human submandibular gland ductal epithelial cells (HSDECs) in normal and IgG4-RD. We examined submandibular gland (SMG) tissue from eight control individuals and 22 patients with IgG4-RD and established an HSDEC culture system. Immunohistochemistry, immunocytochemistry, western blotting, and measurement of transepithelial electrical resistance (TER) were performed. Claudin-4, claudin-7, occludin, and JAM-A were expressed at the apical side of the duct epithelium in submandibular gland (SMG) tissue and at the cell borders in HSDECs of normal and IgG4-RD. The expression and distribution of TJs in SMG tissue were not different in control individuals and patients with IgG4-RD in vivo and in vitro. Although interferon-gamma (IFNγ) generally disrupts the integrity and function of TJs, as manifested by decreased epithelial barrier function, IFNγ markedly increased the epithelial barrier function of HSDECs via upregulation of claudin-7 expression in HSDECs from patients with IgG4-RD. This is the first report showing an IFNγ-dependent increase in epithelial barrier function in the salivary gland duct epithelium. Our results provide insights into the functional significance of TJs in salivary gland duct epithelium in physiological and pathological conditions, including IgG4-RD.