吉田 優

Helicobacter heilmannii induces gastric lymphoid follicles in mice. However, the pathogenic mechanisms behind the induction of gastric lymphoid follicles by H. heilmannii infection have not been elucidated. The aim of this study was to investigate the roles of Peyer's patches (PP) in H. heilmannii-induced immune responses and the development of gastric lymphoid follicles. C57BL/6J and PP deficient mice were infected with H. heilmannii, and in addition to histological and immunohistological examinations, the expression levels of cytokines and chemokines in gastric mucosa were investigated. Gastric lymphoid follicle formation and the infiltration of dendritic cells, B cells, and helper T cells were milder in the PP-deficient mice 1 month after infection, but they were similar in both types of mice after 3 months. The mRNA expression levels of tumor necrosis factor α and CC chemokine ligand 2 were significantly high in the H. heilmannii-infected groups, and CXC chemokine ligand 13 expression was significantly increased in the infected C57BL/6J wild-type mice 1 month after infection. These results suggest that PP are not essential for the formation and development of gastric lymphoid follicles induced by H. heilmannii infection, although they are involved in the speed of gastric lymphoid follicle formation.

偏性嫌気性グラム陽性桿菌であるビフィズス菌は，新生児腸内細菌叢において圧倒的多数を占める．その由来として，母親からの「垂直伝播」が示唆されているが，実際に母親由来ビフィズス菌が子の腸内に伝播しているという直接的な知見は未だ報告されていない．そこで，ビフィズス菌の母親から新生児への菌株レベルでの伝播をパルスフィールドゲル電気泳動（Pulsed-Field Gel Electrophoresis; PFGE）法によって検証した．その結果，5組の母子双方の糞便から Bifidobacterium longum subsp. longum（B. longum）が分離され，このうち3組の母親由来株と新生児由来株のPFGEパターンが組ごとに一致した．次に，これら母親由来株の好気及び微好気条件下での生残性を調べた．その結果，1）培地平板上では好気条件下で6時間，微好気条件下で18時間は初発の菌数を維持すること，2）ヒトの手のひら上では生残数が急速に減少し，3時間で全ての菌が死滅すること，3）好気環境でも乾燥状態では全ての菌が死滅するまでに24時間以上かかることが明らかとなった．これらの結果から，ビフィズス菌は母親の手指よりも産道や大気，器具，衣類等を介して垂直伝播することが示唆された．<br>

GOALS: The predictors of malignant intraductal papillary mucinous neoplasm (IPMN) and invasive IPMN were investigated in this study to determine the optimal indicators of surgical resection for IPMN. BACKGROUND: Recently, international consensus guidelines have described the standard indicators of resection for IPMN. However, the indicators of surgical resection for IPMN, especially for branch duct IPMN, still remain controversial. STUDY: Eighty-two patients with IPMN who underwent surgical resection during April 1998 to January 2009, were retrospectively reviewed and examined with regard to their preoperative factors and pathologic diagnosis. RESULTS: Multivariate analysis showed that main duct IPMN (P<0.01) and earlier diabetes (P=0.03) were independent predictors of malignant IPMN. In branch duct IPMN, the diameter of the main pancreatic duct (MPD) was found to be significantly associated with malignancy by univariate analysis (P=0.034). An elevated serum CA19-9 level (P<0.01) was an independent predictor of invasive IPMN. CONCLUSIONS: Our observations suggest that main duct IPMN, branch duct IPMN with MPD dilatation, and IPMN with an elevated serum CA19-9 level should be considered as indications for surgical resection.

Helicobacter pylori CagA protein is considered a major virulence factor associated with gastric cancer. There are two major types of CagA proteins: the Western and East Asian CagA. The East Asian CagA-positive H. pylori infection is more closely associated with gastric cancer. The prevalence of gastric cancer is quite low in the Philippines, although Philippine populations are considered to originate from an East Asia source. This study investigates the characteristics of the cagA gene and CagA protein in Philippine H. pylori strains and compares them with previously characterized reference strains worldwide. The full-length cagA gene was sequenced from 19 Philippine isolates and phylogenetic relationships between the Philippine and 40 reference strains were analyzed. All Philippine strains examined were cagA positive, and 73.7% (14/19) strains were Western CagA-positive. The phylogenetic tree based on the deduced amino acid sequence of CagA indicated that the Philippine strains were classified into the two major groups of CagA protein: the Western and the East Asian group. These findings suggest that the modern Western influence may have resulted in more Western type H. pylori strains in the Philippines. Therefore, H. pylori-infected Filipinos can be considered to be at a low risk of developing gastric cancer.

OBJECTIVE: Recently, guidelines for the treatment and prevention of ulcers induced by non-steroidal anti-inflammatory drugs (NSAIDs) were established. This study investigated the association between the current adherence to the guidelines and the incidence of gastric mucosal lesions caused by NSAIDs. METHODS: This study included 254 NSAIDs users (128 regular and 126 on-demand users) who had undergone upper gastrointestinal endoscopy. The patients were characterized as high risk based on the following: age 65 years or older, history of peptic ulcers, concurrent use of corticosteroids or anticoagulants, and high-dose NSAIDs use. Adherence was defined as the prescription of NSAIDs with proton pump inhibitors, prostaglandin analogues, or high-dose histamine 2 receptor antagonists in high-risk NSAIDs user. The severity of gastric mucosal lesions was evaluated using the modified LANZA score (MLS). RESULTS: Seventy-nine (61.7%) of the regular NSAIDs users and 65 (51.6%) of the on-demand NSAIDs users met our definition of high-risk patients. Adherence in the regular NSAIDs users and on-demand NSAIDs users was 25 (31.7%) and 16 (24.6%), respectively. The incidence of gastric mucosal lesions (MLS ≧ 1) was significantly higher in the nonadherence group than in the adherence group for both regular NSAIDs users (59.3 vs. 28.0%, P = 0.01) and on-demand NSAIDs users (63.3 vs. 25.0%, P = 0.01). Gastric ulcers in the regular NSAIDs users were more frequently observed in the nonadherence group than in the adherence group (29.6 vs. 4.0%, P < 0.01). CONCLUSION: Nonadherence was associated with a high prevalence of NSAIDs-induced gastric mucosal lesions.

In this article, novel gel-forming materials based on oligomeric and polymeric electrolytes for not only water but also organic solvents, including ionic liquids, are highlighted especially the synthesis, derivatization, and physical property. The oligoelectrolytes with cationic pyridinium backbone can be very easily prepared by the intermolecular quaternization of the ampholytic monomer. The ionene polymers with N,N'-(p-phenylene)dibenzamide linkages as polyelectrolyte were also straightforwardly synthesized in high yields by the copolymerization of 1,4-bis[4-(chloromethyl)benzamide]benzene and commercially available alpha,omega-ditertiary amines. The oligo- and polyelectrolytes provided physical hydrogels under ca. 1-5 wt% of the concentrations after heating and cooling at room temperature without any other additives. These cationic gelators have characteristic properties, such as acid resistance, a self-healing nature after mechanical collapse, and a dispersant ability for single-walled carbon nanotubes, which have been rarely attainable for conventional physical gelators.

症例は55歳男性，左上顎洞形質細胞腫治療後に腹痛と背部痛を主訴に施行された腹部CTにて膵頭体部に70mm大の腫瘤性病変を認めた．血清IgG高値及びERCPにて同部位に膵管狭細像を認めた．悪性リンパ腫，自己免疫性膵炎との鑑別が問題となり，開腹生検にて膵形質細胞腫の確定診断に至った．膵形質細胞腫は非常に稀な疾患であるが，膵に腫瘤性病変，IgG高値，膵管狭細像を認めた際には鑑別診断の一つとして念頭に置くべきであると考えられた．

Citrobacter rodentium, a murine model pathogen for enteropathogenic Escherichia coli, colonizes the surface of intestinal epithelial cells and causes mucosal inflammation. This bacterium is an ideal model for investigating pathogen-host immune interactions in the gut. It is well known that gene transcripts for Th1 cytokines are highly induced in colonic tissue from mice infected with C. rodentium. However, it remains to be seen whether the Th1 or Th2 cytokines produced by antigen-specific CD4(+) T cells provide effective regulation of the host immune defense against C. rodentium infection. To investigate the antigen-specific immune responses, C. rodentium expressing ovalbumin (OVA-C. rodentium), a model antigen, was generated and used to define antigen-specific responses under gamma interferon (IFN-gamma)-deficient or interleukin-4 (IL-4)-deficient conditions in vivo. The activation of antigen-specific CD4(+) T cells and macrophage phagocytosis were evaluated in the presence of IFN-gamma or IL-4 in vitro. IFN-gamma-deficient mice exhibited a loss of body weight and a higher bacterial concentration in feces during OVA-C. rodentium infection than C57BL/6 (wild type) or IL-4-deficient mice. This occurred through the decreased efficiency of macrophage phagocytosis and the activation of antigen-specific CD4(+) T cells. Furthermore, a deficiency in antigen-specific CD4(+) T-cell-expressed IFN-gamma led to a higher susceptibility to mucosal and gut-derived systemic OVA-C. rodentium infection. These results show that the IFN-gamma produced by antigen-specific CD4(+) T cells plays an important role in the defense against C. rodentium.

CagA protein is the most assessed effecter molecule of Helicobacter pylori. In this report, we demonstrate how CagA protein regulates the functions of dendritic cells (DC) against H. pylori infection. In addition, we found that CagA protein was tyrosine-phosphorylated in DC. The responses to cagA-positive H. pylori in DC were reduced in comparison to those induced by cagA-negative H. pylori. CagA-overexpressing DC also exhibited a decline in the responses against LPS stimulation and the differentiation of CD4(+) T cells toward Th1 type cells compared to wild type DC. In addition, the level of phosphorylated IRF3 decreased in CagA-overexpressing DC stimulated with LPS, indicating that activated SHP-2 suppressed the enzymatic activity of TBK1 and consequently IRF3 phosphorylation. These data suggest that CagA protein negatively regulates the functions of DC via CagA phosphorylation and that cagA-positive H. pylori strains suppress host immune responses resulting in their chronic colonization of the stomach.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) causes a wasting syndrome characterized by a loss of body weight accompanied by a decrease in adipose tissue weight, i.e., insulin resistance-like symptoms. Therefore, the effects of TCDD on an insulin signaling pathway in mature 3T3-L1 adipocytes were investigated to obtain insight into the underlying mechanisms. TCDD downregulated expression of insulin receptor beta-subunit (IRbeta), insulin receptor substrate 1 (IRS1), and glucose transporter 4 (GLUT4) and decreased insulin-stimulated glucose uptake activity. TCDD also upregulated expression of TNF-alpha, one of insulin resistance-inducing factors. Anti-TNF-alpha neutralization antibody and silencing of TNF-alpha receptor 1 (TNFR1) diminished the TCDD-induced downregulation of IRbeta, IRS1, and GLUT4. Moreover, the experiments using small interfering RNA for an aryl hydrocarbon receptor (AhR) revealed that the TCDD-evoked changes of IRbeta, IRS1, GLUT4, and TNF-alpha were dependent on AhR. TCDD also stimulated the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase (JNK), and their inhibitors abrogated the TCDD-induced downregulation of IRbeta, IRS1, and GLUT4; upregulation of TNF-alpha; and activation of NF-kappaB. Taken together, TCDD stimulates expression and secretion of TNF-alpha in adipocytes through activation of AhR, ERK1/2, and JNK, and the secreted TNF-alpha causes the downregulation of IRbeta, IRS1, and GLUT4 through TNFR1, resulting in insulin resistance.

Curcumin, a component of turmeric (Curcuma longa), is known to exert a variety of biological functions including anti-inflammatory activity. We examined the inhibitory effects of chemically synthesized derivatives of curcumin against inflammatory responses and compared them with those of curcumin, in order to find derivatives with stronger effects than curcumin. In a cell culture system using the mouse macrophage cell line RAW264.7, monoacetylcurcumin strongly inhibited IkappaB phosphorylation, nuclear factor (NF)-kappaB activation and tumor necrosis factor (TNF)-alpha production induced by lipopolysaccharide (LPS). In addition, oral administration of monoacetylcurcumin to mice led to greater suppression of TNF-alpha production after LPS stimulation than the administration of curcumin or tetrahydrocurcumin in vivo. Monoacetylcurcumin also inhibited the LPS-induced NF-kappaB activation in the liver. Collectively, monoacetylcurcumin is a potential chemopreventive agent for treating inflammatory responses more effectively than curcumin.

Asthma is a chronic inflammatory airway disease characterized by airway hyperreactivity, increased mucus production, and reversible airway contraction. Asthma is a complex genetic trait caused by environmental factors in genetically predisposed individuals. The transportation of maternal antigen-specific IgG via amniotic fluid, placenta and breast milk plays an important role in passive immunity. First, to examine whether maternal passive immunity by the transportation of antigen-specific IgG via FcRn regulates allergic airway inflammation, ovalbumin-immunized FcRn(+/-) female mice were bred with FcRn(-/-) male mice to evaluate the degree of ovalbumin-induced allergic airway inflammation of FcRn(-/-) offspring. Maternal passive immunity regulated allergic airway inflammation in an FcRn-dependent manner. Second, to examine the role of maternal antigen-specific IgG1 injection into mothers, we intravenously injected ovalbumin-specific IgG1 into wild-type or FcRn(+/-) mice immediately after they gave birth. The offspring were sensitized and challenged with ovalbumin. Antigen-specific IgG1 administered to lactating mice reduced allergic airway inflammation in their offspring in an FcRn-dependent manner. Last, to exclude the factor of maternal passive immunity other than ovalbumin-specific IgG1, we administered ovalbumin-specific IgG1 orally to offspring after birth. Oral administration of ovalbumin-specific IgG1 to offspring during the lactating period prevented the development of allergic airway inflammation in an FcRn-dependent manner. These data show that the transfer of maternal antigen-specific IgG regulates the development of allergic airway inflammation early in life in an FcRn-dependent manner.

Lipoxins, which are bioactive lipids derived from omega-6 polyunsaturated fatty acids, play important roles in various biological functions. In this study, the anti-inflammatory effects of lipoxin A(4) (LXA4; 5S,6R,15S-trihydroxy-7,9,13-trans-11-eicosatetraenoic acid) were investigated in in vitro cultured cell experiments and in vivo animal experiments. In mouse peritoneal macrophages and mouse macrophage cell line RAW264.7 cells, LXA4 reduced the lipopolysaccharide (LPS)-induced increase in the mRNA expression level of tumor necrosis factor (TNF)-alpha. LXA4 also reduced the LPS-induced nuclear translocation of nuclear factor-kappaB (NF-kappaB). In an LPS-induced acute inflammation mouse model, the injection of LXA4 at 5 microg/kg b.wt. led to down-regulation of the TNF-alpha level in serum and the TNF-alpha mRNA expression level in intestinal epithelial cells. Moreover, LXA4 reduced the LPS-caused phosphorylation of IkappaB kinases, IkappaB, and NF-kappaB, the degradation of IkappaB, and the nuclear translocation of NF-kappaB in intestinal epithelial cells. In a coculture system using RAW264.7 cells and human colon carcinoma cell line Caco-2 cells, treatment with LXA4 to Caco-2 cells led to reduction of LPS-evoked TNF-alpha production in RAW264.7 cells and interleukin-8 mRNA expression in Caco-2 cells. These results indicate that LXA4 exerts anti-inflammatory effects through inhibition of NF-kappaB activation, and, therefore, LXA4 may be useful as a therapeutic strategy against intestinal mucosa inflammation.

BACKGROUND: We aimed to elucidate the risk factors and preventive factors associated with chronic low-dose aspirin (L-ASA)-induced gastroduodenal mucosal injury in Japanese patients with arteriosclerotic disease. METHODS: This retrospective observational study included 400 L-ASA users who underwent upper gastrointestinal endoscopy. We investigated patients' clinical characteristics, including age, peptic ulcer history, concomitant drugs [i.e. gastric agents, antiplatelet drugs, anticoagulants, non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids], abdominal symptoms, endoscopic findings, and interruption of L-ASA before endoscopy. The severity of gastroduodenal mucosal lesions was evaluated using the modified LANZA score (MLS). RESULTS: Of 400 patients, 249 (62%) and 41 (10%) had gastroduodenal mucosal lesions (MLS ≥1) and gastroduodenal ulcers, respectively. Peptic ulcer history, abdominal symptoms, proton pump inhibitor (PPI), histamine type 2-receptor antagonists (H2RA), and the cessation of L-ASA before endoscopy were significantly associated with L-ASA-induced gastroduodenal ulcers; the odds ratio (OR) (confidence interval (CI)) was 5.49 (1.82-16.55), 4.56 (1.93-10.75), 0.12 (0.03-0.42), 0.13 (0.04-0.40) and 0.11 (0.04-0.29), respectively. Moreover, patients having two or more of five factors [i.e. advanced age (≥75), anticoagulants, antiplatelet drugs, NSAIDs and corticosteroids] had a significantly higher prevalence of L-ASA-induced gastroduodenal ulcers [OR (CI): 2.39 (1.002-5.69)]. CONCLUSION: Peptic ulcer history, abdominal symptoms and the summation of risk factors increased the risk for L-ASA-induced gastroduodenal ulcers. H2RAs and PPIs were effective for the prevention of L-ASA-induced gastroduodenal ulcers. The cessation of L-ASA before endoscopy might lead to the underestimation of L-ASA-induced gastroduodenal injury.

BACKGROUND: Resolvin E1 (RvE1), an endogenous lipid mediator derived from eicosapentaenoic acid, has been identified in local inflammation during the healing stage. RvE1 reduces inflammation in several types of animal models including peritonitis and retinopathy and blocks human neutrophil transendothelial cell migration. The RvE1 receptor ChemR23 is expressed on myeloid cells such as macrophages and dendritic cells. The aim of this study was to determine whether RvE1 regulates colonic inflammation when the innate immune response of macrophages plays a key role in pathogenesis and tissue damage. METHODS: The RvE1 receptor ChemR23 was expressed in mouse peritoneal macrophages as defined by flow cytometry. Peritoneal macrophages were pretreated with RvE1, followed by lipopolysaccharide stimulation, whereupon transcriptional levels of proinflammatory cytokines were analyzed. RESULTS: RvE1 treatment led to inhibition of proinflammatory cytokines including TNF-alpha and IL-12p40. In HEK293 cells, pretreatment with RvE1 inhibited TNF-alpha-induced nuclear translocation of NF-kappaB in a ChemR23-dependent manner. These results suggested that RvE1 could regulate proinflammatory responses of macrophages expressing ChemR23. Therefore, we investigated the beneficial effects of RvE1 in dextran sulfate sodium-induced colitis. RvE1 treatment led to amelioration of colonic inflammation. CONCLUSIONS: These results indicate that RvE1 suppresses proinflammatory responses of macrophages. RvE1 and its receptor may therefore be useful as therapeutic targets in the treatment of human inflammatory bowel disease and other inflammatory disorders.

Helicobacter pylori (H. pylori) chronically colonizes human gastric epithelium and induces various diseases. But the mechanism of carcinogenesis in H. pylori infection remains to be assessed. We described that after attachment of H. pylori to gastric epithelial cells, CagA is injected directly from the bacteria into the cells and undergoes tyrosine phosphorylation. Tyrosine phosphorylated CagA can bind to SHP-2. Deregulation of SHP -2 by CagA may induce abnormal proliferation and movement of gastric epithelial cells. There are two patterns of CagA motifs between East Asian strains and Western strains. East Asian-type CagA confers stronger SHP-2 binding and transforming activities than Western-type CagA. We assessed the association between CagA diversity and clinical outcome in Asian countries, where mortalities from gastric cancer is different. As results, H. pylori infection with East Asian-type CagA was associated with gastric atrophy and cancer. Therefore, persistent active inflammation induced by the East Asian CagA-positive strain may play a role in the pathogenesis of disease.

The pathogenesis of gastroduodenal diseases is related to the diversity of Helicobacter pylori strains. CagA-positive strains are more likely to cause gastric cancer than CagA-negative strains. Based on EPIYA (Glu-Pro-Ile-Tyr-Ala) motifs at the carboxyl terminus corresponding to phosphorylation sites, H. pylori CagA is divided into East Asian CagA and Western CagA. The former type prevails in East Asia and is more closely associated with gastric cancer. The present study used full sequences of the cagA gene and CagA protein of 22 H. pylori strains in gastric cancer and peptic ulcer patients from Southern Vietnam to make a comparison of genetic homology among Vietnamese strains and between them and other strains in East Asia. A phylogenetic tree was constructed based on full amino acid sequences of 22 Vietnamese strains in accordance with 54 references from around the world. The cagA gene was found in all Vietnamese H. pylori strains. Twenty-one of 22 (95.5%) strains belonged to the East Asian type and had similar characteristics of amino acid sequence at the carboxyl terminus to other strains from the East Asian region. From evidence of East Asian CagA and epidemiologic cancerous lesions in Vietnam, H. pylori-infected Vietnamese can be classified into a high-risk group for gastric cancer, but further studies on the interaction among environmental and virulence factors should be done. Finally, phylogenetic data support that there is a Japanese subtype in the Western CagA type.

Probiotics have been used to treat human gastrointestinal inflammations including inflammatory bowel disease (IBD). However, the exact mechanisms by which probiotics act to protect against intestinal inflammation have yet to be fully elucidated. The aim of this study was to evaluate anti-inflammatory effects of Lactococcus lactis subsp. cremoris FC using in vivo and in vitro inflammation models. Colitis was induced in C57BL/6 mice by administration of 3% dextran sulfate sodium to drinking water. In the cellular level assessment, a gut inflammation model with the co-culture system consisting Caco-2 cells and RAW264.7 cells stimulated by LPS was used. Administration of L. lactis subsp. cremoris FC significantly ameliorated shortening of colon length and histological score of the colon in DSS-induce colitis mice. In addition, the treatment of L. lactis subsp. cremoris FC improved the aberrant mRNA expression in inflamed tissue near to control level through notable suppression of TNF-alpha (P<0.05), IFN-gamma (P<0.05), IL-6, iNOS, and MIP-2 mRNA expression. In addition, in a gut inflammation model, treatment with L. lactis subsp. cremoris FC resulted in significant down-regulation of IL-8 mRNA expression in Caco-2 cells and inhibition of NF-kappaB nuclear translocation in RAW264.7 cells. Our findings indicate that administration of L. lactis subsp. cremoris FC improves negative effects of DSS-induced colitis in mice through the inhibition of inflammatory cell infiltration.

BACKGROUND & AIMS: The neonatal Fc receptor for immunoglobulin (Ig)G (FcRn) protects monomeric IgG from catabolism in parenchymal and hematopoietic cells during adult life. In dendritic cells, FcRn also promotes presentation of antigens in association with IgG. Because IgGs with anti-bacterial specificity are a hallmark of inflammatory bowel disease, we sought to determine their significance and relationship to FcRn expression in antigen-presenting cells, focusing on IgGs specific for flagellin. METHODS: Levels of circulating anti-flagellin IgG were induced in wild-type and FcRn(-/-) mice, followed by induction of colitis with dextran sodium sulfate (DSS). Bone marrow chimera models were used to localize the site of FcRn action. RESULTS: Wild-type mice that received anti-flagellin IgG exhibited more severe colitis following administration of DSS, compared with mice that received control IgG. Wild-type mice immunized with flagellin exhibited significantly more severe colitis in response to DSS administration than that observed in similarly treated FcRn(-/-) mice. In chimera studies, FcRn(-/-) mice given wild-type bone marrow and immunized with flagellin exhibited significantly more colitis than wild-type mice given FcRn(-/-) bone marrow and immunized with flagellin. Serum anti-flagellin IgG levels were similar in both sets of chimeric mice, consistent with the equal participation of hematopoietic and nonhematopoeitic cells in FcRn-mediated IgG protection. CONCLUSIONS: Anti-bacterial IgG antibodies are involved in the pathogenesis of colitis; this pathway requires FcRn in antigen presenting cells, the major subset of hematopoietic cells that express FcRn.