Yuhei Inaba

Expression of the antimicrobial peptide α‐defensin/cryptdins in intestinal crypts decreases at the initial phase of intestinal inflammation in a model of inflammatory bowel disease, IL‐10‐deficient mice

Background: The etiology of inflammatory bowel disease (IBD) is associated with an altered microflora due to a failure of the immune system. This study investigated the expression of the intestinal antimicrobial peptide &agr;‐defensin, which plays a pivotal role in the regulation of the intestinal microflora in a representative model of IBD, interleukin (IL)‐10‐deficient mice. Methods: The expression of &agr;‐defensin/cryptdins in IL‐10‐deficient mice was assessed by real‐time polymerase chain reaction (PCR) and acid/urea polyacrylamide gel (AU‐PAGE). The alteration of &agr;‐defensin/cryptdins expression was compared with the inflammatory grade of mice intestine at various weeks from birth. Results: The weight, length, and inflammation grade of the mouse intestines were assessed at 5, 7, 9, 11, 13, and 15 weeks from birth. While the weight of the large intestine was heavier at 15 weeks after birth in the IL‐10‐deficient mice than in the control mice, histological inflammation began from 7 weeks after birth. Real‐time PCR and AU‐PAGE identified a significant decrease in the expression of &agr;‐defensin/cryptdins at 7 weeks after birth in the IL‐10 knockout mice, thus illustrating the involvement of &agr;‐defensin/cryptdins in the etiology of the intestinal inflammation in IBD. This study also identified the expression of &agr;‐defensin/cryptdins to be inversely proportional to age until 11 weeks, suggesting a relationship between the formation of the intestinal microflora and a reduction in the expression of &agr;‐defensin/cryptdins. Conclusions: The altered expression of antimicrobial peptide &agr;‐defensin may cause the onset of intestinal inflammation due to a failure to regulate intestinal microflora. (Inflamm Bowel Dis 2010)

Cytokine Regulation of OCTN2 Expression and Activity in Small and Large Intestine

Background: The organic cation transporter OCTN2 is located on the IBD5 risk allele and has been implicated in the pathogenesis of inflammatory bowel diseases (IBD). OCTN2 is expressed in the apical membrane and transports many solutes including bacteria‐derived mediators that may be involved in host–microbial interactions. To explore its role further, we examined potential regulatory factors in human IBD and in experimental models of OCTN2 expression. Methods: Human colonic epithelial cells (Caco2BBE) were used to investigate the effects of inflammatory mediators on OCTN2 activity and expression. Apical membrane expression of OCTN2 was assessed by surface biotinylation. Rag‐1−/−‐deficient mice were used to determine the potential role of adaptive immune cells in the regulation of OCTN2 expression. C57Bl/6 mice were treated with the cytokines interferon‐gamma (IFN‐&ggr;) and tumor necrosis factor‐alpha (TNF‐&agr;) to determine the effects on OCTN2 expression and activity. OCTN2 expression in human IBD specimens was assessed by Western blotting and immunohistochemistry. Results: OCTN2 activity and expression are regulated by the state of intestinal inflammation. OCTN2 expression in colonic tissues of Rag‐1−/−‐deficient mice was reduced. Treatment with IFN‐&ggr; and TNF‐&agr; increased intestinal OCTN2 expression, particularly in the colon. IFN‐&ggr; increased both total and apical membrane expression of Caco2BBE OCTN2, whereas TNF‐&agr; stimulated apical expression. Colonic epithelial OCTN2 expression was increased in actively inflamed areas of both Crohns disease and ulcerative colitis. Conclusions: Intestinal epithelial OCTN2 expression is increased by intestinal inflammation, most likely through increased levels of proinflammatory cytokines. These findings suggest that OCTN2 may participate to restoration of intestinal homeostasis under conditions of inflammation‐associated stress. (Inflamm Bowel Dis 2011;)

Reduction of syndecan-1 expression in differentiated type early gastric cancer and background mucosa with gastric cellular phenotype

BackgroundSyndecan-1 is known to play a role as a cell adhesion molecule, similar to E-cadherin, and is associated with the maintenance of epithelial morphology. The purpose of this study was to elucidate the role and alterations of syndecan-1 expression in comparison with those of E-cadherin in different cellular phenotypes of differentiated-type gastric cancers (DGCs).MethodsA total of 80 DGCs at an early stage, and their adjacent mucosa, were evaluated by both immunohistochemistry and in situ hybridization. Syndecan-1 and E-cadherin were assessed by immunohistochemical staining with an anti-syndecan-1 and an anti-E-cadherin antibody, respectively. Based on immunohistochemistry, DGCs and their surrounding mucosa were divided into four types: gastric type (G-type), ordinary type (O-type), complete-intestinal type (CI-type), and null type.ResultsThe expression sites of syndecan-1 mRNA mostly coincided with those of syndecan-1 protein. Syndecan-1 expression was significantly lower in G-type cancers (30%) than in O- (81%) and CI-type cancers (92%) (P = 0.0001 and P = 0.004, respectively), but E-cadherin did not show this result. In addition, syndecan-1 expression was significantly reduced in DGCs comprised partly of poorly differentiated adenocarcinoma or signet-ring cell carcinoma, compared to DGCs demonstrating papillary and/or tubular adenocarcinoma (P = 0.02). G-type intestinal metaplasia (IM) surrounding the tumors was observed in 21% of G-type cancers, in 0% of O-, and in 10% of CI-type cancers (P = 0.01; G-type vs O-type). Reduction of syndecan-1 expression was significant in G-type IM (25%) compared to non-G-type IM (75%; P = 0.02).ConclusionsSyndecan-1 plays a role in the growth of G-type cancers at an early stage compared with E-cadherin changes, and the reduction of syndecan-1 expression in IM surrounding the tumors may influence the growth of G-type cancer.

Spontaneous remission of primary diffuse large B-cell gastric lymphoma

Spontaneous and complete disappearance of diffuse large B-cell lymphoma (DLBL) of the stomach is extremely rare. Although regression of gastric DLBL after eradication of Helicobacter pylori has recently been reported, we present two consecutive cases of stage I DLBL of the stomach which disappeared after only nonspecific therapy, including histamine 2-receptor antagonist (H2RA); both cases were documented histologically and endoscopically. Both patients were positive for H. pylori, and later received H. pylori eradication therapy. The disease has not recurred after 11 and 6 months, respectively. Our cases suggest that the option of combination therapy with H2RA either with or followed by H. pylori eradication is appropriate for consideration as an initial approach in standard therapy for stage I diffuse large B-cell gastric lymphoma.

Immunoprecipitation of nucleosomal DNA is a novel procedure to improve the sensitivity of serum screening for the p16 hypermethylation associated with colon cancer

BACKGROUNDnWe developed a novel method of methylation-specific PCR (MSP) using immunoprecipitation with anti-histone antibody (IP-MSP) to efficiently detect serum methylated DNA tightly bound to de-acetylated histones.nnnMATERIALS AND METHODSnThe detection limit of IP-MSP for p16 methylation was determined with a standard made by cell line (SKCO-1) lysate. p16 methylation of tumor and/or serum of 51 colorectal cancers and 10 adenoma patients, and 10 healthy volunteers was detected with conventional MSP or IP-MSP.nnnRESULTSnIP-MSP detected p16 methylation from 0.5pg/mul of the cell lysate. The sensitivity of IP-MSP for detecting serum p16 methylation in 27 patients with tumors characterized by p16 methylation was significantly higher than that with conventional method (81% versus 59%), particularly in Stage II patients (91% versus 45%). IP-MSP detected no p16 hypermethylation in sera of adenoma patients and volunteers.nnnCONCLUSIONSnIP-MSP is thus considered to be a promising procedure to detect serum methylated DNA in colorectal cancer patients.

Collagenous colitis appeared after 6-year administration of lansoprazole

Collagenous colitis (CC) is one of the causes of undefined watery diarrhea, which is histologically accompanied by thickening of the subepithelial collagen layer. CC associated with lansoprazole normally occurs within several weeks after initial administration, but no case presenting after long-term administration of lansoprazole has yet been reported. A 77-year-old male with 6-year history of administration of lansoprazole complained of watery diarrhea and weight loss. Colonoscopy revealed disappearance of vascular networks and red spots in the sigmoid colon. Biopsy specimen showed erosion and collagen bands thickened, so the patient was diagnosed as CC. After lansoprazole discontinuation, the watery diarrhea disappeared and histological abnormalities improved.

Capsule endoscopy is a feasible procedure for identifying a Diphyllobothrium nihonkaiense infection and determining the indications for vermifuge treatment.

Diphyllobothrium is a member of Cestoda family, which is the largest parasite of humans. The diagnosis of diphyllobothriasis is based on the detection of eggs in the stool. Because the remainder of the scolex causes a relapse in diphyllobothriasis, the scolex must be completely discharged to cure the parasite infection. However, the scolex or forefront of the Diphyllobothrium is difficult to detect with gastroduodenoscopy and colonoscopy, because most Diphyllobothrium attach to the jejunal wall. In the present case, capsule endoscopy detected proglottids as well as forefront of the parasite at jejunum. Based on the results of capsule endoscopy, the patient underwent additional vermifuge (anthelminthic) treatment to cure the diphyllobothriasis and discharged a worm measuring 3 m in length with a scolex. Capsule endoscopy is a practical option to determine whether additional vermifuge treatment is required through the detection of the proglottids as well as a scolex or forefront of the parasite.

Soluble bioactive microbial mediators regulate proteasomal degradation and autophagy to protect against inflammation-induced stress

Bifidobacterium breve and other Gram-positive gut commensal microbes protect the gastrointestinal epithelium against inflammation-induced stress. However, the mechanisms whereby these bacteria accomplish this protection are poorly understood. In this study, we examined soluble factors derived from Bifidobacterium breve and their impact on the two major protein degradation systems within intestinal epithelial cells, proteasomes and autophagy. Conditioned media from gastrointestinal Gram-positive, but not Gram-negative, bacteria activated autophagy and increased expression of the autophagy proteins Atg5 and Atg7 along with the stress response protein heat shock protein 27. Specific examination of media conditioned by the Gram-positive bacterium Bifidobacterium breve (Bb-CM) showed that this microbe produces small molecules (<3 kDa) that increase expression of the autophagy proteins Atg5 and Atg7, activate autophagy, and inhibit proteasomal enzyme activity. Upregulation of autophagy by Bb-CM was mediated through MAP kinase signaling. In vitro studies using C2BBe1 cells silenced for Atg7 and in vivo studies using mice conditionally deficient in intestinal epithelial cell Atg7 showed that Bb-CM-induced cytoprotection is dependent on autophagy. Therefore, this work demonstrates that Gram-positive bacteria modify protein degradation programs within intestinal epithelial cells to promote their survival during stress. It also reveals the therapeutic potential of soluble molecules produced by these microbes for prevention and treatment of gastrointestinal disease.

Obscure gastrointestinal bleeding occurring 50 years after an appendectomy

A 69-year-old male, with a history of an appendectomy 50u2005years previously, presented to hospital due to refractory dizziness and bloody stool. A routine blood test revealed that he had severe anaemia. Upper and lower endoscopy revealed no evidence of bleeding in the oesophagus, stomach, duodenum, terminal ileum or colorectum. He was diagnosed as having obscure gastrointestinal bleeding.1 Capsule endoscopy (CE) was performed and dark-bluish areas with whitish villi were detected in the jejunum (figure 1). Subsequently, double-balloon endoscopy (DBE) was performed orally and multiple dark-bluish areas coated with whitish villi were found at the distal jejunum (figure 2A), and white debris also oozed from …