Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: HUMANGGP:017444 (TNF)
 61,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The immunological and genetic pathogeneses of inflammatory bowel disease (IBD) have been well studied, but not well elucidated in recent years. Accordingly, the pharmacological treatment of IBD is focusing upon the individual pathologic step (targeting therapy). It has recently become apparent that new drugs such as biological immunomodulating agents and anti-inflammatory cytokines have better short-term effects in some respects than conventional drugs, and they could change the treatment strategy of IBDs in the near future. Many options are now available to treat IBD. The choice depends on the type of IBD, the location of inflammation and the severity of symptoms. Many key processes in the inflammatory cascade have been targeted by cytokine and anticytokine therapies ranging from antigen presentation, T cell activation, overproduction of pro-inflammatory cytokines and migration of inflammatory cells to blockade of effector signals. TNF-alpha plays an important role in the induction of other cytokines as well as in the upregulation of adhesion molecules in chronic IBDs, Crohn's disease (CD) and ulcerative colitis. In fact, the most successful approaches so far in the treatment of IBD have been anti-TNF strategies. In contrast, the use of antiadhesion molecules strategies has been demonstrated to be ineffective in IBD.
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PMID:Emerging biotherapies for inflammatory bowel disease. 1466 93

The aims of this study were: 1) to obtain an experimental model reproducing the characteristics of chronicity and spontaneous relapses found in inflammatory bowel disease (IBD) and 2) to correlate these changes with intestinal motility and bacteria translocation. For this purpose, two groups of Sprague-Dawley rats were used: a treated group that received two subcutaneous injections of indomethacin (7.5 mg/kg) 48 h apart and a control group that received saline. Blood leukocytes, TNF, and fecal parameters were monitored for 90 days after treatment. In treated rats, a cyclic oscillation of blood leukocytes and TNF concomitant with an inverse correlation of fecal output was observed. Treated rats were then selected either during their highest or lowest blood leukocyte values for motor activity and microbiological evaluation. Controls were obtained in age-matched rats. Rats with high leukocyte levels showed a decrease of motor activity. In contrast, animals with low leukocyte levels presented hypermotility. Bacterial overgrowth accompanied by bacterial translocation was found in the group with high leukocytes, whereas no differences were observed between the control and indomethacin groups during the lowest leukocyte phase. We obtained a model of IBD characterized by a chronic cyclic oscillation of intestinal motility, flora, and inflammatory blood parameters. During the high-leukocyte stage, motor activity decrease is related to bacterial translocation. This phase is followed by a reactive one characterized by hypermotility associated with a decrease in both bacterial growth and leukocytes. However, as in IBD, this reaction seems unable to prevent a return to relapse.
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PMID:Intestinal motor disorders associated with cyclical bacterial overgrowth in a rat model of enteritis. 1496 48

Genetic factors have a definitive role in the etiology of ulcerative colitis (UC). The mode of inheritance suggests a polygenic disease with the penetrance of the genetic factors being strongly influenced by environmental factors. Several studies have been reported associations between UC and the polymorphism of genes that are located in the major histocompatibility complex (MHC) on the short arm of chromosome 6. The human leukocyte antigen (HLA) class II genes are candidates for a role in the pathogenesis of UC, because their products play a central role in the immune response. The MHC region contains numerous immune related genes, and it has now become clear that different alleles of the MHC genes are strongly linked. Association studies have suggested a role for HLA-DR alleles in disease susceptibility to UC. Thus, HLA-DRB1*0103, DRB1*1502 and DRB1*12 were found to be positively associated with UC. On the other hand, the tumor necrosis factor alpha (TNF-alpha) gene encodes a proinflammatory cytokine that is found in increased concentrations in the mucosa of patients with inflammatory bowel disease. The regulation of TNF expression is in part genetically determined because the polymorphisms -238, -308, -863, -857, and -1031 found in the promoter region are associated with increased TNF production. Recent data suggests that TNF polymorphism may be more important in determining susceptibility to UC and these TNF markers could predict response to infusion with chimeric anti-TNF antibody.
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PMID:[Immunogenetics of chronic ulcerative colitis]. 1501 40

Biologic therapies, namely antibodies against tumor necrosis factor-alpha (TNF- alpha) or its receptors, have been recently introduced for the treatment of patients with inflammatory bowel disease (IBD). In the present study the effects of cloricromene, an agent with known antithrombotic actions and with demonstrated anti-TNF- alpha activity were investigated in a rat model of experimental colitis induced with dinitrobenzenesulphonic acid (DNB)/ethanol. We investigated three experimental groups: (i) sham-colitis with vehicle-treatment (controls, n = 6), (ii) colitis with vehicle-treatment (saline, 0.1 ml s.c., daily) (DNB-V, n = 7), (iii) colitis with cloricromene-treatment (10 mg/kg/day s.c.; DNB-C, n = 8). After 7 days, the weight gain, colon wet weight, macroscopic damage score, coagulation parameters, colon mucosal myeloperoxidase activity (MPO), and tissue concentrations of TNF- alpha and of macrophage inhibitory peptide-2 (MIP-2) were assessed. The macroscopic damage scores, colon wet weights, and tissue MIP-2 levels were significantly increased in untreated and in cloricromene-treated rats compared with controls. Cloricromene treatment was associated with a minor body weight loss (p < 0.025) and significantly reduced tissue concentrations of MPO and TNF-alpha (p < 0.02, both). Blood coagulation parameters were not affected by treatment. In the DNB-model treatment with cloricromene effectively reduces tissue levels of TNF- alpha and of myeloperoxidase, whereas MIP-2 concentrations were not influenced. Blood coagulation parameters remained unchanged indicating safety of treatment. Since biological therapies frequently fail to improve disease course of IBD, other therapies with similar targets should be further investigated.
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PMID:A protective effect of the synthetic coumarine derivative Cloricromene against DNB-colitis in the rat. 1504 89

TNF can potentiate IFN-gamma production by activated T cells and other members of the TNF-superfamily play key roles in this effect. A newly discovered TNF-superfamily cytokine (TL1A) could also be involved in initiating or promoting the Th1 response by enhancing IFN-gamma production. The purpose of this study was to assess the role of recombinant TL1A on IFN-gamma production by cultured PBMC and lamina propria LPMC and to determine whether TL1A expression is altered in inflammatory bowel disease. IFN-gamma, but not IL-4 or IL-10 production by PBMC and LPL, was dose-dependently augmented by TL1A (or by activation of its receptor, death domain receptor 3 [DR3], with specific mAb) independently of, but in synergy with, IL-12 and IL-18. T cell activating stimuli induced expression of TL1A on the cell membrane (mb-TL1A) in a fraction of peripheral blood (PB) T cells. In the intestinal mucosa, a fraction of lamina propria (LP) T cells, especially CD4+ cells, constitutively expressed mb-TL1A, and the fraction increased in mucosal inflammation. A higher fraction of cells also express the TL1A receptor DR3 in ulcerative colitis and Crohn's disease. TL1A transcript was several times more abundant in RNA from mucosal biopsies taken from inflamed Crohn's disease lesions than in those taken from uninvolved areas. Expression of TL1A and its receptor DR3 by lamina propria mononuclear cells (LPMC) could have significant influence on the severity of mucosal inflammation.
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PMID:Potential role for TL1A, the new TNF-family member and potent costimulator of IFN-gamma, in mucosal inflammation. 1520 83

T-cells are causally involved in the pathogenesis of inflammatory bowel disease (IBD). The tryptophan-metabolizing enzyme indoleamine 2,3-dioxygenase (IDO) regulates T-cell proliferation and survival. We show in this report that IDO mRNA is markedly induced in lesional colonic biopsies of IBD patients. IDO is primarily expressed in CD123(+) mononuclear cells infiltrating the submucosal areas of the inflamed lesions. In Crohn's disease (CD), IDO is also strongly expressed in perifollicular regions of lymphoid follicles. Upregulation of IDO is of functional significance, as we detected an increase of kynurenine and of the kynurenine/tryptophan ratio in supernatants from colonic explant cultures (CECs) of CD patients. Immunohistochemistry of colonic biopsies taken from CD patients prior and after treatment with the TNF-blocking antibody Infliximab revealed reduced IDO expression in patients with good clinical response to Infliximab. In summary, high local expression of IDO may represent an anti-inflammatory mechanism tempting to counterbalance the tissue-damaging effects of activated T-cells infiltrating the colonic mucosa in IBD.
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PMID:Overexpression of indoleamine 2,3-dioxygenase in human inflammatory bowel disease. 1538 May 29

The production of CRP occurs almost exclusively in the liver by the hepatocytes as part of the acute phase response upon stimulation by IL-6, TNF-alphaand IL-1-betaoriginating at the site of inflammation. Its short half-life makes CRP a valuable marker to detect and follow up disease activity in Crohn's disease (CD). In contrast, ulcerative colitis has only a modest to absent CRP response despite active inflammation, and the reason for this is unknown. In CD, serum levels of CRP correlate well with disease activity and with other markers of inflammation as the CDAI, serum amyloid, IL-6 and faecal calprotectin. CRP is a valuable marker for predicting the outcome of certain diseases as coronary heart disease and haematological malignancies. An increased CRP (>45 mg/L) in patients with IBD predicts with a high certainty the need for colectomy and this by reflecting severe ongoing and uncontrollable inflammation in the gut. Finally, trials with anti-TNF and anti-adhesion molecules have shown that a high CRP predicts better response to these drugs. However, whether we need to include CRP as an inclusion criterion for future trials with biologicals is still a matter of debate.
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PMID:C-reactive protein as a marker for inflammatory bowel disease. 1547 32

Conventional therapy for inflammatory bowel diseases rely on corticosteroids and 5-aminosalicylates combined with immunosuppressive agents for maintenance. These drugs are not always effective and may inflict serious side effects. Other therapies are therefore awaited. Infliximab, a monoclonal antibody against the pro-inflammatory cytokine TNF-alpha has been successfully applied as a treatment for Crohn's disease. The mechanism of action of this drug extends beyond the level of TNF-alpha scavenging and includes induction of apoptosis of effector cells. Numerous anti-TNF antibodies have been developed and are currently evaluated in clinical trials. Other targets for monoclonal antibodies include integrins and cytokines involved in T-cell differentiation and activation. Likewise recombinant proteins that moderate TNF bioactivity and lymphocyte function have been developed. The therapeutic effect of recombinant interleukin-10 seems to be dependent on local delivery of the protein. Antisense therapy targeting lymphocyte migration has also been tested in IBD. Finally, the conventional drug thalidomide and possibly MAP-kinase inhibitors may become novel treatment entities for IBD.
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PMID:New cytokine therapeutics for inflammatory bowel disease. 1558 91

The TNF superfamily cytokine, lymphotoxin-like inducible protein that competes with glycoprotein D for binding herpesvirus entry mediator on T cells (LIGHT; TNFSF14), can augment T cell responses inducing IFN-gamma production and can drive pathological gut inflammation when expressed as a transgene in mouse T cells. LIGHT expression by human intestinal T cells suggests the possibility that LIGHT may play a key role in regulation of the mucosal immune system. A nonenzymatic method was developed for the isolation of T cells from the human lamina propria, permitting analysis of native cell surface protein expression. Cell surface LIGHT was constitutively expressed on mucosal T and NK cells and a subpopulation of gut-homing CD4(+) T cells in the periphery. In addition, CD2-mediated stimulation induced efficient LIGHT expression on intestinal CD4(+) T cells, but not on peripheral blood T cells, suggesting a gut-specific, Ag-independent mechanism for LIGHT induction. By contrast, herpesvirus entry mediator expression on gut T cells was unperturbed, implicating the transcriptional regulation of LIGHT as a mechanism modulating signaling activity in the gut. Quantitative analysis of LIGHT mRNA in a cohort of inflammatory bowel disease patients indicated elevated expression in biopsies from small bowel and from inflamed sites, implicating LIGHT as a mediator of mucosal inflammation.
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PMID:LIGHT is constitutively expressed on T and NK cells in the human gut and can be induced by CD2-mediated signaling. 1563 82

Therapeutic interventions in the case of gastrointestinal disease are based on the understanding of the role of different inflammatory mediators. Reactive O2 and N2 metabolites are involved in IBD. Pro-inflammatory cytokines, apoptosis signalling and redox-response transcription factors are depended on free radicals. NO activates COX enzymes. PGE2 negatively modulates induction of NO synthase by interleukins and therefore regulation of gastric mucosal integrity by endogenous NO depends on arachidonic acid cascade. PG-s have pro-inflammatory and anti-inflammatory effects on the immune system. Dietary PUFA-s and eicosanoids have potential effects on the modulation of inflammatory processes and immune cells. The cholesterol level lowering activity of several cytokines and colony stimulating factor can be observed. Therapeutic efficacy of N-3 PUFA is described in cases of patients with chronic gastrointestinal disorders, but N-3 PUFA-s only delay early relapse of ulcerative colitis in remission. TNF is known as a pleiotropic cytokine. Strategies for TNF in IBD is very important part of therapeutical approaches. Therapy with infliximab and related ones are encouraging in critical cases. It is also believed recently, that NF-kappaB also may be a target of IBD treatment. It became known, that oxidized LDL can inhibit LPS-induced binding of the NF-kappaB to DNA and the subsequent expression of TNF-alpha and interleukin-1beta in macrophages as well as oxidized LDL modulates activation of NF-kappaB in mononuclear phagocytes by altering the degradation of I-kappaBs. 15-d-PGJ2 inhibits multiple steps in the NF-kappaB signaling pathway. 15-d-PGJ2 metabolite binds PPAR-gamma promotes adipocyte differentiation. PPAR-gamma ligand inhibits growth of cells through induction of apoptosis. Several nutritional polyphenols (the secondary metabolites of plants) are COX2 and/or LOX inhibitors and iNOS activators. The moderate nutritional customs with natural antioxidants can help restore to normal function of gastrointestinal tract, but the immoderate consumption of vitamins and polyphenol type antioxidant molecules is contraindicated.
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PMID:[Cytokines, prostaglandins, nutritive and non-nuitritive factors in inflammatory bowel diseases]. 1566 52


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