Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0021390 (inflammatory bowel disease)
 23,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glucocorticoids inhibit the expression and action of most cytokines. This is part of the in vivo feed-back system between inflammation-derived cytokines and CNS-adrenal produced corticosteroids with the probable physiological relevance to balance parts of the host defence and anti-inflammatory systems of the body. Glucocorticoids modulate cytokine expression by a combination of genomic mechanisms. The activated glucocorticoid-receptor complex can (i) bind to and inactivate key proinflammatory transcription factors (e.g. AP-1, NF kappa B). This takes place at the promotor responsive elements of these factors, but has also been reported without the presence of DNA; (ii) via glucocorticoid responsive elements (GRE), upregulate the expression of cytokine inhibitory proteins, e.g. I kappa B, which inactivates the transcription factor NF kappa B and thereby the secondary expression of a series of cytokines; (iii) reduce the half-life time and utility of cytokine mRNAs. In studies with triggered human blood mononuclear cells in culture, glucocorticoids strongly diminish the production of the 'initial phase' cytokines IL-1 beta and TNF-alpha and the 'immunomodulatory' cytokines IL-2, IL-3, IL-4, IL-5, IL-10, IL-12 and IFN-gamma, as well as of IL-6, IL-8 and the growth factor GM-CSF. While steroid treatment broadly attenuates cytokine production, it cannot modulate it selectively, e.g. just the TH0, the TH1 or the TH2 pathways. The production of the 'anti-inflammatory' IL-10 is also inhibited. The exceptions of steroid down-regulatory activity on cytokine expression seem to affect 'repair phase' cytokines like TGF-beta and PDGF. These are even reported to be upregulated, which may explain the rather weak steroid dampening action on healing and fibrotic processes. Some growth factors, e.g. G-CSF and M-CSF, are only weakly affected. In addition to diminishing the production of a cytokine, steroids can also often inhibit its subsequent actions. Because cytokines work in cascades, this means that steroid treatment can block expression of the subsequent cytokines. The blocked cytokine activity does not depend on a reduced cytokine receptor expression; in fact available in vitro investigations show that while the cytokine expression is blunted, its receptor is upregulated. The cellular studies presented here may represent the maximum potential of steroids to modulate cytokine expression in human mononuclear cells. It remains to be determined by clinical-experimental studies how effective cytokine modulation can be achieved in situ in inflamed bowel by systemic or by topical steroid therapy. Such studies may also answer whether a blocked cytokine production/action is the key or just a secondary mechanism behind the unique efficacy of steroids in active inflammatory bowel disease.
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PMID:Cytokine modulation by glucocorticoids: mechanisms and actions in cellular studies. 889 6

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

Mononuclear cell proliferative response to IL-2 and functional response to IL-4 is disturbed in IBD. The aim of the present study was to verify whether altered expression of the common gamma chain (gamma c) might contribute to this abnormality. The gamma c expression on peripheral blood mononuclear cells was analyzed by flow cytometry using a monoclonal antibody to gamma c. IL-4 binding in association with gamma c expression was assessed using biotinylated IL-4 in two-color flow cytometry. Mean fluorescence of gamma c expression was significantly decreased in active CD patients as compared to inactive CD and healthy controls (P < 0.05). Cell activation as a possible reason for gamma c down-regulation was confirmed using the in vitro stimulated donor cells. In the same system it was shown that down-regulation of gamma c is accompanied by decreased numbers of IL-4 binding cells. In conclusion, a decreased expression of the gamma c on peripheral blood mononuclear cells from CD patients with active disease might have an important pathogenetic significance in this chronic intestinal disorder.
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PMID:Expression of common gamma chain on peripheral blood mononuclear cells in Crohn's disease. 905 22

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

Over the past few years, application of targeted gene deletion and transgenic approaches has led to the often unanticipated development of rodent lines which develop inflammatory bowel disease. While none of these lines recapitulate the histopathological and clinical features usually associated with human inflammatory bowel disease (IBD) in their entirety, many exhibit key features comprising the development of "spontaneous" chronic and acute inflammation. These models include targeted deletion of the genes encoding IL-2, IL-10, TGF beta, T-cell receptor alpha/beta, keratin 8, and Gi2 alpha. In addition, animals expressing transgenes for the human WA-B27 (with beta-2 microglobulin) as well as a dominant negative construct which functionally blocks N-cadherin have also been observed to result in chronic inflammatory bowel disease. Most of the mutant murine lines experience a diffuse colitis, but some (HLA-B27 transgenic and IL-10-deficient) also experience small bowel inflammation. The variety of manipulations provides some important broad insights: (1) IBD can result from dysregulation of mucosal immune responses or impairment of epithelial barrier function, and (2) the natural history of inflammation resulting from mutation at a single genetic loci is substantially modulated by other genetic factors. With the rapidly-increasing variety of mutant mice, comparison of the residual components of immune system in lines developing IBD with those of lines not developing IBD, it is possible to deduce a requirement for TCR gamma/delta CD4+ lymphocytes as well as pivotal role of IFN gamma and (as a suppressive factor) IL-10. Study of a number of models has demonstrated the important interaction between environmental factors and genetic predisposition. Thus, in at least some of the lines (IL-2-deficient and HLA-B27) the inflammatory bowel disease is not observed when the mutant mice are maintained in a germ-free environment but does develop after reconstitution with a pathogen-free flora. In the TCR alpha/beta deficient mice, appendectomy in the neonatal period prevents the subsequent development of colitis. In still other models, inflammation may not occur without some challenge by an exogenous external agent, e.g., mice deficient in intestinal trefoil factor (ITF) exposed to dextran sodium sulfate (1). These models offer great promise to permit further dissection of the various constituents of the intestinal epithelium and mucosal immune response systems which are necessary for maintaining normal homeostasis and which can contribute to the development of inflammatory bowel disease. Further, they offer powerful tools for exploring the interaction between genetic and environmental factors to explicate the pathogenesis of inflammatory bowel disease and to develop new therapeutic intervention strategies.
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PMID:Lessons from genetic models of inflammatory bowel disease. 926 Mar 28

A severe, Th1-mediated experimental colitis with similarities to inflammatory bowel disease in humans can be induced by a single injection of 2,4,6-trinitrophenol (TNP)-substituted protein plus adjuvant in IL-2-/- mice. To determine the early events involved in the pathogenesis of IL-2-/-colitis, we compared the function of lamina propria (LP) T cells from IL-2-/- and IL-2+/+ mice subjected to disease-inducing (TNP-conjugated keyhole limpet hemocyanin [TNP-KLH]) and disease-inhibiting (anti-CD3) immunization protocols. We show that LP T cells in TNP-KLH-immunized IL-2-/- mice fail to produce TGF-beta early (day 2), whereas LP T cells in TNP-KLH-immunized IL-2+/+ mice exhibit an approximately eightfold rise in TGF-beta secretion. The critical importance of local TGF-beta production was further substantiated by the following findings. 1) LP T cells from TNP-KLH-immunized IL-2-/- mice administered anti-CD3 (i.p.) exhibit a significant rise in TGF-beta, production but fail to produce IFN-gamma, and such mice do not develop colitis. 2) TNP-KLH-immunized IL-2-/- mice administered anti-CD3 and coadministered anti-TGF-beta mAb again give rise to IFN-gamma-producing LP cells, and such mice develop colitis. 3) TNP-KLH-immunized IL-2+/+ mice administered anti-TGF-beta mAb exhibit pockets of mononuclear cell infiltrates in the LP. These results indicate that the disposition of IL-2-/- mice to develop chronic colonic inflammation is due to a Th1 cell response in the LP that is not appropriately counter-regulated by the production of the suppressor cytokine, TGF-beta.
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PMID:TGF-beta production regulates the development of the 2,4,6-trinitrophenol-conjugated keyhole limpet hemocyanin-induced colonic inflammation in IL-2-deficient mice. 931 62

Scid mice develop a severe, chronic, and lethal IBD 3-6 months after engraftment of gut wall from immunocompetent congenic donors, induced by donor-derived CD4+ T cells migrating from the graft. We have investigated intracellular T-helper type 1 (Th1) cytokines in the spleens of gut wall-transplanted scid mice with IBD. Increased fractions of interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha) and IL-2-positive CD4+ T cells were found in the spleens of diseased mice compared with control mice. Moreover, a small but significant population of CD4+ T cells which stained positive for granulocyte-macrophage colony-stimulating factor (GM-CSF) was found in scid mice with IBD but was virtually absent in congenic non-scid control mice. Cloning of granulocyte/ macrophage colony-forming cells (G/M-CFC) revealed that both non-transplanted scid mice and scid mice with IBD had an 8-14-fold increase in splenic G/M-CFC compared with control mice. No significant difference in the number of G/M-CFC per total spleen was found between non-transplanted and disease scid mice, although both groups of mice showed a nearly two-fold increase compared with control mice. G/M-CFC were never found in the thymus, liver or lymph nodes of diseased mice. Immunohistochemistry revealed that the multinucleated giant cells observed in the gut wall of diseased mice did not represent haematopoietic foci, but were derived from macrophages. These observations point towards a dominant role for Th1-type CD4+ T cells in the immunopathogenesis of IBD, whereas haematopoiesis does not seem to be affected by the development of the disease.
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PMID:Splenic T helper cell type 1 cytokine profile and extramedullary haematopoiesis in severe combined immunodeficient (scid) mice with inflammatory bowel disease (IBD). 947 77

Severe combined immunodeficient (scid) mice engrafted with small pieces of full thickness gut wall from immunocompetent syngenic donors develop a chronic and lethal colitis. Lymphocytes from the lamina propria of engrafted mice were analyzed for phorbol ester/ionomycin-induced cytokine production by intracellular staining. A 4-5-fold increase in the fraction of IFN-gamma-producing CD4+ lamina propria T cells was found in moderately and severely diseased mice when compared to healthy congenic C.B-17 control mice. The number of IL-2-producing T cells was increased by approximately 2-fold when comparing mice suffering from severe disease to healthy control mice. The fraction of TNF-alpha positive CD4+ T cells was increased by a factor of two in both moderately and severely diseased mice. When analyzing Th2 cytokines, it was found that the levels of IL-4-producing CD4+ T cells was not altered in diseased animals, whereas the fraction IL-10-producing CD4+ T cells was reduced by a factor of 20. The combined data showed a 15-25-fold increase in the Th1/Th2 ratio of diseased mice when compared to healthy control mice. No intracellular cytokines could be detected in lymphocytes not treated with phorbol ester/ionomycin. The present data identify a prominent role for Th1-type T helper cells in the immunopathogenesis of gut wall graft-induced inflammatory bowel disease in scid mice.
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PMID:Increased intracellular Th1 cytokines in scid mice with inflammatory bowel disease. 948 17

C3H/HeJBir mice are a new substrain that spontaneously develop colitis early in life. This study was done to determine the T cell reactivity of C3H/HeJBir mice to candidate antigens that might be involved in their disease. C3H/HeJBir CD4+ T cells were strongly reactive to antigens of the enteric bacterial flora, but not to epithelial or food antigens. The stimulatory material in the enteric bacteria was trypsin sensitive and restricted by class II major histocompatibility complex molecules, but did not have the properties of a superantigen. The precursor frequency of interleuken (IL)-2-producing, bacterial-reactive CD4+ T cells in colitic mice was 1 out of 2,000 compared to 1 out of 20,000-25,000 in noncolitic control mice. These T cells produced predominately IL-2 and interferon gamma, consistent with a T helper type 1 cell response and were present at 3-4 wk, the age of onset of the colitis. Adoptive transfer of bacterial-antigen-activated CD4+ T cells from colitic C3H/HeJBir but not from control C3H/HeJ mice into C3H/HeSnJ scid/scid recipients induced colitis. These data represent a direct demonstration that T cells reactive with conventional antigens of the enteric bacterial flora can mediate chronic inflammatory bowel disease.
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PMID:CD4+ T cells reactive to enteric bacterial antigens in spontaneously colitic C3H/HeJBir mice: increased T helper cell type 1 response and ability to transfer disease. 950 Jul 88

Budesonide, a beta-adreno-receptor agonist, is comparable to corticosteroid in the treatment of patients with inflammatory bowel disease with the advantage of minimal side effect. Although the immunomodulatory effects of budesonide on the circulatory and respiratory mucosal immune system have been reported, its effect on the human gut immune system has not been published. In this study, the effect of budesonide on the human gut immune system was compared to methyl-prednisolone. The cellular immune function was measured in-vitro by DNA synthesis, ornithine decarboxylase (ODC) activity and TNFalpha secretion. We found that both drugs have a comparable inhibitory effect on DNA synthesis, ODC activity and suppression of TNFalpha secretion. Exogenous addition of IL-2, did not restore the antiproliferative effect of both drugs. We conclude that budesonide has a comparative suppressive effect to methyl-prednisolone on the gut immune system which is not related to IL-2 secretion. The antiproliferative response may explain the therapeutic effect of budesonide on patients with inflammatory bowel disease.
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PMID:Immunosuppressive effect of budesonide on human lamina propria lymphocytes. 950 28


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