UMLS:C0009319 - FACTA Search

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Query: UMLS:C0009319 (colitis)
19,384 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the production of proinflammatory cytokines (IL-1 beta, IL-6, IL-8, and TNF-alpha) and immunoregulatory cytokines (IL-2, IFN-gamma, and IL-10) in the colonic mucosa of patients with active ulcerative colitis (UC), inactive UC, and non-inflammatory bowel disease (IBD) colitis by organ culture. The production of proinflammatory cytokines was significantly increased in all the studied groups compared with controls. In active UC, levels of these cytokines, except for IL-1 beta, were markedly increased compared with non-IBD colitis, and the levels were positively correlated with the degree of inflammation. Patients with non-refractory active UC receiving steroids showed levels of IL-1 beta and TNF-beta production similar to those in controls. IL-10 production was also significantly increased in all the studied groups, the value of being the highest in active UC. In contrast, IL-2- and IFN-gamma production was significantly decreased in both active and inactive UC compared with controls, and the values in active UC were inversely correlated with the degree of inflammation. In non-IBD colitis, decreased IL-2 production was observed, but IFN-gamma production did not differ from that in controls. In an experimental study, each of the proinflammatory cytokines was injected into the colonic mucosa of rats. All of these proinflammatory cytokines, except for IL-1 beta induced colonic mucosal damage that showed some histologic features similar to those of UC. These results suggest that the increased production of proinflammatory cytokines, particularly of IL-6 and IL-8, and the decreased production of IL-2- and IFN-gamma, probably downregulated by the enhanced production of IL-10, play an important role in the pathogenesis of UC.
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PMID:The role of proinflammatory and immunoregulatory cytokines in the pathogenesis of ulcerative colitis. 856 92

There is now increasing evidence that hyperresponsiveness towards intestinal flora is a crucial event in the pathogenesis of inflammatory bowel disease (IBD). In support of this hypothesis, we recently described in humans that tolerance exists towards indigenous intestinal flora but is broken in active IBD lesions. In the present study, we have attempted to transfer this model into mice from different genetic backgrounds (BALB/c, SJL/J, C3H/HeJ). We found that mononuclear cells from spleen, small bowel and large bowel of mice do not proliferate, i.e. are tolerant when exposed to bacterial sonicates derived from autologous intestine (BsA) but do proliferate, i.e. are immune when exposed to bacterial sonicates derived from the heterologous intestine of syngenic littermates (BsH). Furthermore, we demonstrate that both local and systemic tolerance to BsA is broken in a murine model of chronic intestinal inflammation induced by the hapten reagent 2, 4, 6-trinitrobenzene sulfonic acid (TNBS), which mimics several important characteristics of Crohn's disease. Tolerance to BsA was restored and TNBS-induced colitis was abrogated in mice systemically treated with interleukin (IL)-10 or antibodies to IL-12. Treatment specifically restored tolerance to BsA, but did not suppress proliferation to BsH. In summary, we here report a new model for the study of immunity and tolerance towards bacterial products. Our data suggest that tolerance to BsA is an important protective mechanism and that restoration of tolerance intestinal flora by IL-10 and antibodies to IL-12 may be of potential therapeutic utility in patients with inflammatory bowel disease.
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PMID:Tolerance towards resident intestinal flora in mice is abrogated in experimental colitis and restored by treatment with interleukin-10 or antibodies to interleukin-12. 862 91

In previous studies we showed that a chronic colitis associated with a Th1 T cell response can be induced by the rectal administration of the haptenizing reagent 2,4,6-trinitrobenzene sulfonic acid (TNBS). We report here that oral administration of haptenized colonic proteins (HCP) before rectal administration of TNBS effectively suppresses the ability of the latter to induce colitis. This suppression (oral tolerance) appears to be due to the generation of mucosal T cells producing TGF-beta and Th2-type cytokines after oral HCP administration. Peyer's patch and lamina propria CD4+ T cells from HCP-fed animals stimulated with anti-CD3/anti-CD28 had a 5-10-fold increase in their production of TGF-beta and secreted increased amounts of IL-4 and IL-10 but lower levels of IFN-gamma in comparison to T cells from ovalbumin-fed control animals. In addition, the colons of HCP-fed mice showed strikingly increased TGF-beta but decreased IL-12 expression by immunohistochemical studies and isolated mononuclear cells from HCP-fed animals secreted less IL-12 heterodimer. Finally, and most importantly, the suppressive effect of orally administered HCP was abrogated by the concomitant systemic administration of anti-TGF-beta or rIL-12 suggesting a reciprocal relationship between IL-12 and TGF-beta on tolerance induction in TNBS-induced colitis. In parallel studies we demonstrated that TNBS-induced colitis can be transferred to naive recipient animals with purified CD4+ T cells from the colon of TNBS-treated animals and that such animals develop lethal pancolitis when exposed to very low doses of TNBS. Feeding of HCP suppressed this sensitivity to TNBS, indicating that oral feeding can suppress the response of pre-committed T cells in vivo. These studies suggest for the first time that TGF-beta production can abrogate experimental granulomatous colitis even after such colitis is established, and thus, that regulation of TGF-beta levels may have relevance to the treatment of human inflammatory bowel disease.
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PMID:Experimental granulomatous colitis in mice is abrogated by induction of TGF-beta-mediated oral tolerance. 867 81

Mice rendered deficient in the production of interleukin 10 (IL-10-/-) develop a chronic inflammatory bowel disease (IBD) that predominates in the colon and shares histopathological features with human IBD. Our aim was to identify which cell type(s) can mediate colitis in IL-10-/- mice. We detected an influx of immunoglobulin-positive cells into the colon and the presence of colon-reactive antibodies in the serum of IL-10-/- mice. To assess a pathogenic role for B cells, we generated a B cell-deficient (B-/-) strain of IL-10-/- mice. B-/-IL-10-/- mice acquired a severe colitis analogous to that IL-10-/- mice, implying that B cells were not the primary mediator of IBD in this model. A series of cell transfer experiments was performed to assess a pathogenic role for T cells. When IL-10-/- T cell-enriched lamina propria lymphocytes (LPL) or intraepithelial lymphocytes (IEL) were transferred into immunodeficient recombinase-activating gene (RAG)-2-/- recipients, a mild to severe colitis developed, depending on the cell number transferred. Lymphocytes recovered from the colon of transplanted RAG-2-/- mice with colitis were predominantly alpha beta TCR+CD4+, including a large proportion of CD4+CD8 alpha + cells. These cells were also CD45RB-/low and CD44+, indicative of an activated/memory population. Individual populations of CD4+CD8 alpha-, CD4+CD8 alpha + and CD4-CD8 alpha + T cells were then isolated from the lamina propria compartment of IL-10-/- mice and transferred into RAG-2-/- recipients. Only IL-10-/- CD4-expressing LPL, including both the CD4+CD8 alpha- and CD4+CD8 alpha + populations, induced colitis in recipient mice. Interferon-gamma, but little to no IL-4, was produced by CD4+CD8 alpha- and CD4+CD8 alpha + LPL recovered from the inflamed colons of RAG-2-/- recipients implicating alpha T helper cell 1 (TH1)-mediated response. We thus conclude that colitis in IL-10-/- mice is predominantly mediated by TH1-type alpha beta TCR+ T cells expressing CD4 alone, or in combination with the CD8 alpha molecule.
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PMID:T helper cell 1-type CD4+ T cells, but not B cells, mediate colitis in interleukin 10-deficient mice. 869 Nov 38

The mechanisms of wound healing in the gut are poorly understood but are mediated by cytokines in other tissues. In this study we wanted to determine which cytokines were expressed after nonspecific colonic injury, the kinetics of that expression, and how cytokine expression correlated with tissue histology. At 0, 4, 8, 12, 24, 48, and 72 h after intrarectal administration of 3% acetic acid to C3H/HeJ mice, their colons were removed for histology, organ culture, and RNA extraction. Cytokine mRNA expression for various cytokines was assessed by reverse transcriptase-polymerase chain reaction with primers specific for each cytokine. Cytokine production in organ cultures was measured with bioassays. Shortly after colonic injury and during colonic regeneration, proinflammatory cytokines such as interleukin-1 beta (IL-1 beta), IL-6, tumor necrosis factor-alpha (TNF-alpha), macrophage inflammatory protein (MIP), and transforming growth factor-beta (TGF-beta) were expressed. In contrast, expression of T cell-derived cytokines was not detected at any time point. Cytokines such as IL-1 beta, IL-6, IL-10, TNF-alpha, and MIP-1 are important mediators of tissue repair and restitution after nonspecific colonic injury and may subserve a similar role in human colitis.
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PMID:Kinetics of cytokine expression during healing of acute colitis in mice. 876 Jan 16

Recent studies have demonstrated that the treatment of mice with anti-gp39 antibodies impairs T-cell functions in the murine collagen type II-induced arthritis model, in acute semi-allogenic graft-versus-host disease, and in the allo-specific CTL-reaction, that is, reactions that are believed to be mediated by Th1-type T cells. On the other hand, the administration of anti-gp39 antibody did not influence Th2 T-cells responses, suggesting that CD40-CD40L interactions are more crucial for Th1 than Th2 T-cell development. Recent studies also demonstrate that dendritic cells (DC) are capable of driving a Th1 T-cell response that is mediated by IL-12. In addition, stimulation of CD40 on human monocytes results in IL-12 production, suggesting that activated T cells expressing CD40L may directly induce the production of IL-12 by antigen-presenting cells, thus allowing for the generation of a Th1 T-cell response in the absence of intracellular pathogens. We investigated whether the CD40-CD40L interaction was important in the production of IL-12 by DCs in an in vitro system that allowed precise control of cytokine concentrations. Initially we showed that FACS-purified mouse spleen DCs produce high amounts of IL-12 p40 in response to CD40 crosslinking by CD40L-expressing fibroblasts. We then demonstrate that DCs also produce IL-12 p40 in a more physiologic system using purified DCs pulsed with ovalbumin (OVA) and then cultured with LECAM-1hi T cells from ovalbumin T-cell receptor transgenic mice. Finally, we show that IL-10 has a potent capacity to shut down CD40-induced IL-12 p40 secretion; and, in addition, IL-4 partially inhibits CD40-induced IL-12 p40 secretion and enhances IL-10-mediated inhibition in an additive fashion. We also investigated the in vivo relevance of this interaction in an experimental model for a Th1-mediated disease, the hapten reagent (TNBS)-induced colitis. The administration of anti-gp39 (CD40L) antibodies during the induction phase of the Th1 response completely prevented IFN-gamma production by CD4 T cells from the intestinal lamina propria and also the clinical and histological evidence of disease. In further studies we showed that the prevention of disease activity was due to an inhibition of IL-12 secretion. Thus, the injection of recombinant IL12 p75 heterodimer into TNBS + anti-gp39-treated mice reversed the effect of anti-gp39 and resulted in severe disease activity. In conclusion, these findings suggest that DCs produce IL-12 in response to CD40 signaling, that a mechanism by which IL-4 may induce Th2 development is by acting with IL-10 to inhibit IL-12 production by DCs, and that the CD40L-CD40 interaction is crucial for the IL-12-dependent priming of Th1 T cells in vivo.
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PMID:Interleukin-12 production by dendritic cells. The role of CD40-CD40L interactions in Th1 T-cell responses. 895 22

Mice with targeted deletion of the G protein G(alpha)i2 develop an inflammatory bowel disease closely resembling ulcerative colitis. To better define disease pathogenesis, the mucosal immune system in G(alpha)i2-deficient mice was studied. Phenotypic analysis of large intestine lamina propria lymphocytes revealed a large increase in memory CD4+ T cells (CD44high, CD45RBlow, CD62Llow). Furthermore, expression of the mucosal homing receptor integrin beta7 was increased on mucosal, but not systemic, CD4+ T cells. Analysis of cytokine production revealed a marked increase in proinflammatory Th1-type cytokines in inflamed colons, as compared with wild-type mice or G(alpha)i2-deficient mice without colitis. Thus, IFN-gamma and IL-1beta levels were increased 13-fold and 30-fold, respectively, with more modest increases in IL-6 levels (5-fold) and TNF levels (2-fold). Inflamed colons of G(alpha)i2-deficient mice also demonstrated increased IL-12 p40 mRNA levels. No increase in IL-2, IL-4, IL-5, and IL-10 was seen. Large intestinal epithelial cells in G(alpha)i2-deficient mice with colitis were found by immunohistochemistry to express increased levels of both MHC class I and class II Ags. Colitis was associated with increased IgG levels (60-fold increase), predominantly IgG2a (135-fold increase), in large but not small intestinal secretions. This was shown by ELISPOT analysis to result from local production within the lamina propria.
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PMID:G(alpha)i2-deficient mice with colitis exhibit a local increase in memory CD4+ T cells and proinflammatory Th1-type cytokines. 901 44

Our studies have elucidated, in part, the mechanism whereby persistent stimulation by normal enteric antigens leads to the development of chronic enterocolitis in interleukin 10-deficient (IL-10-/-) mice. This disease is mediated by IL-10-/- CD4+ T cells as evidenced by their ability to transfer colitis to immunodeficient RAG-2-/- mice. Furthermore, the CD4+ T cells recovered from the affected colons of IL-10-/- mice consisted of a highly polarized Th1-like population because they produced interferon-gamma (IFN-gamma) but not IL-4. We found that enterocolitis could be prevented if 3-week-old mutants were treated for 6-8 weeks with either anti-IL-12 or anti-IFN-gamma monoclonal antibodies (mAb). These results were consistent with the findings of in vitro studies suggesting that IFN-gamma and, in particular, IL-12 direct the differentiation of naive T cells toward a Th1 phenotype. Apparently, the uncontrolled production of IL-12 and IFN-gamma by accessory cells and T cells, respectively, in IL-10-/- mice ultimately resulted in the excessive generation and activation of Th1 cells, hence, immunopathology. IL-10-/- mice have also been used to evaluate the importance of IL-10 in regulating immune responses outside of the gastrointestinal (GI) tract. In these studies, IL-10-/- mice were challenged with a variety of foreign antigens using different routes of administration. In general, the results repeatedly demonstrated that a major function of IL-10 is to protect the host from the harmful side effects of an overly zealous immune-inflammatory response. However, other studies have confirmed speculations that the potent immunosuppressive activities of IL-10 may, under certain circumstances, increase the host's susceptibility to infection with certain types of pathogenic organisms.
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PMID:Studies with IL-10-/- mice: an overview. 910 24

Interleukin (IL)-10 is a pleiotropic cytokine which inhibits a broad array of immune parameters including T helper cell type 1 (Th1) cytokine production, antigen presentation, and antigen-specific T cell proliferation. To understand the consequences of altered expression of IL-10 in immune models of autoimmune disease, the response to infectious agents, and the response to tumors, we developed transgenic mice expressing IL-10 under the control of the IL-2 promoter. Upon in vitro stimulation, spleen cells from unimmunized transgenic mice secrete higher levels of IL-10 and lower amounts of IFN-gamma than do controls, although no gross abnormalities were detected in lymphocyte populations or serum Ig levels. Transfer of normally pathogenic CD4(+) CD45RBhigh splenic T cells from IL-10 transgenic mice did not cause colitis in recipient severe combined immunodeficiency mice. Furthermore, co-transfer of these transgenic cells with CD4(+) CD45RBhigh T cells from control mice prevented disease. Transgenic mice retained their resistance to Leishmania major infection, indicating that their cell-mediated immune responses were not globally suppressed. Lastly, in comparison to controls, IL-10 transgenic mice were unable to limit the growth of immunogenic tumors. Administration of blocking IL-10 mAbs restored in vivo antitumor responses in the transgenic mice. These results demonstrate that a single alteration in the T cell cytokine profile can lead to dramatic changes in immune responses in a manner that is stimulus dependent. These mice will be useful in defining differences in inflammatory conditions and cellular immunity mediated by IL-10.
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PMID:Altered immune responses in interleukin 10 transgenic mice. 918 82

One of the major advances in the understanding of inflammatory bowel disease has been the observation that mice with immunoregulatory defects, such as interleukin-2 knockout (IL-2 -/-) mice, develop spontaneous gut inflammation. Here we have characterized the immune response in the ileum, caecum and colon of these mice before and after the onset of colitis by examining the cellular infiltrate, the cytokines produced by these cells and the mucosal vascular addressin MAdCAM-1. IL-2 -/- mice developed colitis after 35 days of age and before this the mice were apparently healthy. IL-2 -/- mice aged over 35 days with colitis had large numbers of CD4+, CD8+, alpha beta T-cell receptor (TCR)+ and gamma delta TCR+ T cells, macrophages, dendritic cells and MAdCAM-1+ endothelial cells in the caecum and colon. This was associated with an increase in the number of interferon-gamma (IFN-gamma), IL-1 and tumour necrosis factor-alpha (TNF-alpha) transcripts and a decrease in IL-4 and IL-10 transcripts. Treatment of IL-2 -/- mice with cyclosporin A significantly delayed mortality. Interestingly, IL-2 -/- mice under 35 days, although healthy, did show some subtle immunological signs of preclinical disease. There was a significant increase in the number of macrophages and dendritic cells in the colonic lamina propria and increased mRNA for IL-1 and TNF-alpha. There were also increased numbers of MAdCAM-1+ endothelial cells, but IFN-gamma transcripts were not elevated. These results suggest that T-cell-mediated colitis in IL-2 -/- mice may be secondary to an initial non-specific inflammation.
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PMID:Characterization of the mucosal cell-mediated immune response in IL-2 knockout mice before and after the onset of colitis. 920 68

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