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1.
The immunological and genetic basis of inflammatory bowel disease   总被引:2,自引:0,他引:2  
The inflammatory bowel diseases (IBDs), Crohn's disease and ulcerative colitis, are chronic inflammatory disorders of the gastrointestinal tract. Enormous progress has been made recently in understanding the pathogenesis of these diseases. Through the study of patients and mouse models, it has emerged that Crohn's disease is driven by the production of interleukin-12 (IL-12) and interferon-gamma (IFN-gamma), whereas ulcerative colitis is probably driven by the production of IL-13. A second area of progress is in the identification of specific genetic abnormalities that are responsible for disease. The most important finding is the identification of mutations in the gene that encodes NOD2 (nucleotide-binding oligomerization domain 2) protein in a subgroup of patients with Crohn's disease. Here, we discuss these recent findings and the implications for therapy.  相似文献   

2.
The mechanisms responsible for development of inflammatory bowel disease (IBD) have not been fully elucidated, although the main cause of disease pathology is attributed to up-regulated inflammatory processes. The aim of this study was to investigate frequencies of polymorphisms in genes encoding pro-inflammatory and anti-inflammatory markers in IBD patients and controls. We determined genotypes of patients with IBD (n= 172) and healthy controls (n= 389) for polymorphisms in genes encoding various cytokines (interleukin (IL)-1beta, IL-6, tumour necrosis factor (TNF), IL-10, IL-1 receptor antagonist). Association of these genotypes to disease incidence and pathophysiology was investigated. No strong association was found with occurrence of IBD. Variation was observed between the ulcerative colitis study group and the control population for the TNF-alpha-308 polymorphism (p= 0.0135). There was also variation in the frequency of IL-6-174 and TNF-alpha-308 genotypes in the ulcerative colitis group compared with the Crohn's disease group (p= 0.01). We concluded that polymorphisms in inflammatory genes are associated with variations in IBD phenotype and disease susceptibility. Whether the polymorphisms are directly involved in regulating cytokine production, and consequently pathophysiology of IBD, or serve merely as markers in linkage disequilibrium with susceptibility genes remains unclear.  相似文献   

3.
Heat shock protein 32 (Hsp32, hemoxygenase-1) is induced by reactive oxygen metabolites (ROM) and degrades heme leading to the formation of antioxidant bilirubin. Increased mucosal generation of ROM occurs in gastritis and inflammatory bowel disease. We aimed to assess mucosal expression of Hsp32 in normal stomach and colon and to test the hypothesis that disease-related differential expression occurs in inflamed tissue. Gastric body and antral mucosal biopsies were obtained from 33 patients comprising Helicobacter pylori-negative normal controls (n = 8), H pylori-negative gastritis patients (n = 11), and H pylori-positive gastritis patients (n = 14). Forty-seven archival colonic mucosal biopsies selected comprised normal histology (n = 10), active ulcerative colitis (UC) (n = 9), inactive UC (n = 8), active Crohn's disease (CD) (n = 8), inactive CD (n = 6), and other colitides (n = 6). Hsp32 expression in formalin-fixed sections was assessed by avidin-biotin peroxidase immunohistochemistry using a polyclonal rabbit anti-Hsp32 as the primary antibody. Immunohistochemical staining identified Hsp32 in all groups. Diffuse cytoplasmic staining was seen in gastric and colonic epithelial and lamina proprial inflammatory cells. Staining scores for Hsp32 were higher in antral H pylori-positive (P = 0.002) and H pylori-negative (P = 0.02) gastritis than in controls and in body H pylori-positive gastritis than in the other 2 groups (P < 0.01). Expression of Hsp32 was increased in active UC compared with inactive disease (P = 0.03) and normal controls (P = 0.02). In conclusion, Hsp32 is expressed constitutively in normal gastric and colonic mucosa, and differential expression occurs in these tissues when they are inflamed. Upregulation of Hsp32 may be an adaptive response to protect mucosa from oxidative injury in patients with gastritis and inflammatory bowel disease.  相似文献   

4.
BACKGROUND: Patients with inflammatory bowel disease have lower prevalence of Helicobacter pylori infection, but the exact reason for this is not yet clear. AIM: To examine whether the antibiotics frequently used in inflammatory bowel disease are responsible for the lower prevalence of H. pylori infection. Patients with chronic obstructive pulmonary disease on prolonged previous antibiotic therapy were used for comparison. METHODS: Presence/absence of H. pylori infection was detected by a (13)C-urea breath test in 133 patients with inflammatory bowel disease (82 ulcerative colitis, and 51 Crohn's disease) and compared with that of 135 patients with chronic obstructive pulmonary disease and with two age-matched control groups (200 patients each). Primary disease location, duration of disease and detailed analysis of previous and current medication (dose and duration of antibiotics, steroids, 5-aminosalicylic acid) were analysed in each cases. RESULTS: Seventeen of the 133 patients with inflammatory bowel disease [12.2% (10/82) of ulcerative colitis and 13.7% (7/51) of Crohn's disease] and 90/135 patients with chronic obstructive pulmonary disease (66.7%) were positive for H. pylori. A total of 78/200 (39%) for the inflammatory-bowel-disease-group-matched controls and 110/210 (55%) for the chronic-obstructive-pulmonary-disease-matched controls were positive for H. pylori. The history of any antibiotic or steroid therapy had no influence on H. pylori status of patients with inflammatory bowel disease. CONCLUSION: The prevalence of H. pylori compared to the age-matched controls is significantly lower in patients with inflammatory bowel disease but not in those with chronic obstructive pulmonary disease. Antibiotic use is not responsible for the lower prevalence of H. pylori infection in patients with inflammatory bowel disease.  相似文献   

5.
Activated polymorphonuclear leucocytes, which are accumulated in inflammatory lesions of inflammatory bowel disease, produce tissue destructive, oxygen derived free radicals and other inflammatory mediators. The PMN superoxide production elicited by formyl-methionyl-leucyl-phenylalanine or the complement split product 5a were compared in IBD and healthy volunteers. Significantly reduced superoxide production was found in PMNs from patients with Crohn's disease as compared to normal controls, when fMLP or CSa were used as stimulants (p < 0.001 and p < 0.01, respectively), whereas no differences were found when ulcerative colitis patients were compared to normal controls (p > 0.05). The enhanced oxygen derived free radical production previously reported in active IBD, and especially in CD intestinal lesions, may either be due to an accumulation of productive phagocytes or to a change of the inflammatory profile of these cells when migrating into intestinal lesions, possibly due to interaction with other mediators (e.g. adhesion molecules and interleukins).  相似文献   

6.
Seventy-eight patients, 47 with Crohn's disease and 31 with ulcerative colitis, were studied using 99mTc-HMPAO-labelled leukocytes, in order to assess the reliability of the scan in evaluating the location and activity of the disease. The granulocyte integrity was assessed by evaluating the lung wash-out and the early liver and spleen uptake using a 20 minute initial dynamic study. The results of the leukocyte scan revealed a high correlation with radiological and endoscopic findings in the diagnosis of the inflamed bowel segments. The disease activity correlated well with uptake in the bowel, graded from 0 to 3. The leukocyte scan exactly documented the activity in the 9 cases of Crohn's disease located in the ileum and in 5 cases in which the endoscopic exploration was hampered by scarring. Four fistulae were correctly visualized. Moreover, the change in activity after therapy in 6 patients was documented. This technique provides images of excellent quality, superior to those obtainable with indium-111.  相似文献   

7.
The distribution of radioactivity after the oral administration of sucralfate labelled with technetium-99m was studied in 33 patients with Crohn''s disease (13 adults, 20 children), 10 with ulcerative colitis (four adults), and 29 controls (23 with upper intestinal disease, four irritable bowel, one hypolactasia, and one malrotation of the gut). Positive scans were obtained in all patients with ulcerative colitis and 29 of 31 with active Crohn''s disease. The scans of two patients with inactive Crohn''s disease were negative. There were two false negative scans in patients with Crohn''s colitis and one false positive scan. Overall, sensitivity was 95% and specificity 97%. Comparison with radiology in 39 patients showed similar distribution of disease in 24 and more extensive disease in 12. The scan was inexpensive, simple to perform, well tolerated, allowed small and large bowel to be visualised simultaneously, and used a lower dose of radiation than barium studies. It may prove useful as a screening test for inflammatory bowel disease and in the serial assessment of disease activity.  相似文献   

8.
The genetics and immunopathogenesis of inflammatory bowel disease   总被引:1,自引:0,他引:1  
Genome-wide association studies efficiently and powerfully assay common genetic variation. The application of these studies to Crohn's disease has provided insight into the immunopathogenesis of this disease, implicating a role for genes of the innate and adaptive immune systems. In this Review, I discuss our current understanding of the genetics and immunopathogenesis of Crohn's disease and ulcerative colitis. Crohn's disease, but not ulcerative colitis, is associated with genetic variation in NOD2 and an autophagy gene, ATG16L1, both of which affect the intracellular processing of bacterial components. By contrast, variation in the gene encoding the interleukin-23 (IL-23) receptor subunit, as well as in the IL12B, STAT3 and NKX2-3 gene regions, is associated with both Crohn's disease and ulcerative colitis. Comparative analyses of gene associations between these two inflammatory bowel diseases reveal common and unique mechanisms of their immunopathogenesis.  相似文献   

9.
The clinical features of ulcerative colitis and Crohn''s disease are similar to those of infections of the bowel, although their cause is uncertain. Many bacteria that cause intestinal diseases adhere to the gut mucosa, and adhesion of pathogenic Escherichia coli is resistant to D-mannose. The adhesive properties of isolates of E coli were assessed by assay of adhesion to buccal epithelial cells with mannose added. The isolates were obtained from patients with inflammatory bowel diseases (50 with a relapse of ulcerative colitis, nine with ulcerative colitis in remission, 13 with Crohn''s disease, and 11 with infectious diarrhoea not due to E coli) and 22 controls. The median index of adhesion to buccal epithelial cells (the proportion of cells with more than 50 adherent bacteria) for E coli from patients with ulcerative colitis in relapse was significantly higher (43%) than that for controls (5%) and patients with infectious diarrhoea (14%). The index was not significantly different among isolates from patients with ulcerative colitis in relapse, Crohn''s disease (53%), and ulcerative colitis in remission (30%). If an index of adhesion of greater than 25% is taken as indicating an adhesive strain 86% of isolates of E coli from patients with inflammatory bowel disease were adhesive compared with 27% from patients with infective diarrhoea and none from controls. The adhesive properties of the isolates from patients with inflammatory bowel disease were similar to those of pathogenic intestinal E coli, raising the possibility that they may have a role in the pathogenesis of the condition; the smaller proportion of adhesive isolates in patients with infective diarrhoea due to other bacteria suggests that the organism may be of primary importance rather than arising secondarily.  相似文献   

10.
The role of cell-mediated cytotoxicity in the pathogenesis of ulcerative colitis and Crohn's disease has been controversial since reports indicating either a decreased, or an increased, activity of cytotoxic T cells in active stages of inflammatory bowel disease exist. Some of these discrepancies may be attributed to the fact that so far mostly peripheral blood lymphocytes rather than intestinal T cells have been examined. To overcome some of these limitations we performed in situ hybridizations for the detection of perforin and granzyme A mRNA expressing cells, i.e. of cytotoxic cells activated in situ, in the affected intestinal mucosa. These studies revealed increased frequencies of activated, cytotoxic T cells in active stages of ulcerative colitis and Crohn's disease. Interestingly, activated perforin mRNA expressing T cells are present both in the CD4 and in the CD8 T cell subsets. In the latter T cell subset up to 60% of the mucosal T cells isolated from the affected sites express perforin mRNA at detectable levels. The elevated frequency of activated cytotoxic cells and their histological distribution also in close proximity to the epithelial cells may thus indicate an important role for cytotoxic cells in the pathogenesis of inflammatory bowel disease since activated cytotoxic T cells may further exacerbate the inflammatory process through the production of pro-inflammatory cytokines such as interferon-gamma or tumor necrosis factor-alpha, but also through the release of pro-inflammatory cytokines and chemokines upon lysis of epithelial cells and the increased influx of luminal antigens at the site of epithelial erosions.  相似文献   

11.
Over the past decade, much has been learned regarding the role of various cytokines in the pathogenesis of inflammatory bowel disease. Several cytokine 'knockout' models in mice have been shown to develop colitis, while alterations in the production of various cytokines has been documented in human Crohn's disease and ulcerative colitis. In recent years, attempts have been made to treat these diseases through modulation of cytokine production or action. This review focuses on the cytokines that have been implicated in the pathogenesis of inflammatory bowel disease. The evidence for and against a role for particular cytokines in intestinal inflammation is reviewed, as is the experimental and clinical data suggesting that cytokines are rational targets for the development of new therapies.  相似文献   

12.
Summary. Nitric oxide synthase (NOS) activities are responsible for the enzymatic conversion of L-arginine into NO and L-citrulline. Relatively low amounts of NO are produced in intestinal epithelial cells or are released from nerve endings. The effects of NO production are related to the maintenance of epithelial integrity and permeability. A pathological role of an increased NO production has been suggested to play a role in models of experimental colitis. In humans, NOS activity in colon mucosa from patients with ulcerative colitis is clearly increased when compared with the activity of the control group. In contrast, an increase of NOS activity in the colon mucosa from patients with Crohn's disease remains controversial. In the present work, we have measured NOS activity in colon biopsies originating from the control group (n = 16), from patients with ulcerative colitis (n = 23) and Crohn's disease (n = 17) using the radiochemical method of the conversion of L-[guanido-14C] arginine into radioactive L-citrulline. In the control group, NOS activity was mainly of the inducible type (88% of total NOS activity) since it was characterised by its insensibility to the absence of calcium in the assay medium. In colon biopsies originating from patients with ulcerative colitis, inducible NOS activity was increased 3 fold (p < 0.005) and in patients with Crohn's disease, inducible NOS activity was increased 5 fold (p < 0.005). Correlations between NOS activity in colon biopsies and the intensity parameters of the disease i.e. Truelove index, endoscopic score and histo-logical parameters were evidenced in patients with ulcerative colitis. In contrast, in patients with Crohn's disease, the high inducible NOS activity was not correlated with any intensity parameters of the disease. From these data, we concluded that although inducible NOS activity was increased several fold in colon biopsies originating from patients with both ulcerative colitis and Crohn's disease, a correlation between this activity and the severity of bowel inflammation was not found in either cases. Received August 7, 1999  相似文献   

13.
Dysregulation of innate and adaptive intestinal immune responses to bacterial microbiota is supposed to be involved in pathogenetic mechanisms of inflammatory bowel diseases (IBDs). We investigated expression of Toll-like receptor 2 (TLR2), TLR4, and their transmembrane coreceptor CD14 in biopsy samples from patients with IBD and in non-inflamed gut mucosa from controls. Small intestine and colon samples were obtained by colonoscopy from patients with Crohn's disease (CD), ulcerative colitis (UC), and controls. Immunohistochemical analysis of cryostat sections using polyclonal and monoclonal antibodies specific for TLR2, TLR4, and CD14 showed a significant increase in TLR2 expression in the terminal ileum of patients with inactive and active UC against controls. Significant upregulation of TLR4 expression relative to controls was found in the terminal ileum and rectum of UC patients in remission and in the terminal ileum of CD patients with active disease. CD14 expression was upregulated in the terminal ileum of CD patients in remission and with active disease, in the cecum of UC patients in remission and with active disease, and in rectum of UC patients with active disease. Hence, dysregulation of TLR2, TLR4, and CD14 expression in different parts of the intestinal mucosa may be crucial in IBD pathogenesis.  相似文献   

14.
Paf-acether (platelet-activating factor, paf) is one of the most potent inflammatory mediators synthesised by and acting on most inflammatory cells. Paf causes gastric ulcerations and ischemic bowel necrosis. Recently, we described the presence of paf in stools of patients bearing ileal pouch-anal anastomosis with pouchitis. These findings prompted us to search for the presence of paf in stools of patients suffering from inflammatory bowel diseases: Crohn's disease and ulcerative colitis. The fraction corresponding to paf isolated from stools exhibited the same physicochemical and biological characteristics as synthetic paf. Reverse-phase high performance liquid chromatography revealed 80% of C16 and 20% of C18 paf. The presence of a biologically active phospholipid in human stools may bring new perspectives with respect to the study of gastrointestinal diseases as well as the use of paf antagonists in the treatment of inflammatory bowel diseases.  相似文献   

15.
Inflammatory bowel diseases (IBD) including Crohn's disease (CD) and ulcerative colitis (UC) have a major impact on the health of individuals and populations. Accurate diagnosis of inflammatory bowel disease (IBD) at an early stage, and correct differentiation between Crohn's disease (CD) and ulcerative colitis (UC), is important for optimum treatment and prognosis. We present here the first characterization of fecal extracts obtained from patients with CD and UC by employing a noninvasive metabonomics approach, which combines high resolution 1H NMR spectroscopy and multivariate pattern recognition techniques. The fecal extracts of both CD and UC patients were characterized by reduced levels of butyrate, acetate, methylamine, and trimethylamine in comparison with a control population, suggesting changes in the gut microbial community. Also, elevated quantities of amino acids were present in the feces from both disease groups, implying malabsorption caused by the inflammatory disease or an element of protein losing enteropathy. Metabolic differences in fecal profiles were more marked in the CD group in comparison with the control group, indicating that the inflammation caused by CD is more extensive in comparison with UC and involves the whole intestine. Furthermore, glycerol resonances were a dominant feature of fecal spectra from patients with CD but were present in much lower intensity in the control and UC groups. This work illustrates the potential of metabonomics to generate novel noninvasive diagnostics for gastrointestinal diseases and may further our understanding of disease mechanisms.  相似文献   

16.
Fibrosis is a major complication of chronic inflammation, as seen in Crohn's disease and ulcerative colitis, two forms of inflammatory bowel diseases. To elucidate inflammatory signals that regulate fibrosis, we investigated gene expression changes underlying chronic inflammation and fibrosis in trinitrobenzene sulfonic acid-induced murine colitis. Six weekly 2,4,6-trinitrobenzene sulfonic acid enemas were given to establish colitis and temporal gene expression patterns were obtained at 6-, 8-, 10-, and 12-wk time points. The 6-wk point, TNBS-w6, was the active, chronic inflammatory stage of the model marked by macrophage, neutrophil, and CD3(+) and CD4(+) T cell infiltrates in the colon, consistent with the idea that this model is T cell immune response driven. Proinflammatory genes Cxcl1, Ccl2, Il1b, Lcn2, Pla2g2a, Saa3, S100a9, Nos2, Reg2, and Reg3g, and profibrogenic extracellular matrix genes Col1a1, Col1a2, Col3a1, and Lum (lumican), encoding a collagen-associated proteoglycan, were up-regulated at the active/chronic inflammatory stages. Rectal administration of the NF-kappaB p65 antisense oligonucleotide reduced but did not abrogate inflammation and fibrosis completely. The antisense oligonucleotide treatment reduced total NF-kappaB by 60% and down-regulated most proinflammatory genes. However, Ccl2, a proinflammatory chemokine known to promote fibrosis, was not down-regulated. Among extracellular matrix gene expressions Lum was suppressed while Col1a1 and Col3a1 were not. Thus, effective treatment of fibrosis in inflammatory bowel disease may require early and complete blockade of NF-kappaB with particular attention to specific proinflammatory and profibrogenic genes that remain active at low levels of NF-kappaB.  相似文献   

17.
Deletion of exon CD44v7 abrogates experimental colitis by apoptosis induction in intestinal mononuclear cells. Here we show that CD44v7 expression was upregulated upon CD40 ligation in human mononuclear cells, and examined whether ligation of CD44v7 also affects activation and apoptosis in lamina propria mononuclear cells (LPMC) from Crohn's disease (CD) patients. Thirty five patients with chronic inflammatory bowel disease (IBD), fourteen controls and four patients with diverticulitis were evaluated. CD44v7 was upregulated predominantly in the inflamed mucosa of CD patients. Furthermore, incubation with an anti-CD44v7 antibody induced apoptosis in LPMC isolated from inflamed mucosa of CD patients, but not from non-inflamed mucosa, from patients with ulcerative colitis (UC) or from normal controls. CD40 ligation and simultaneous incubation with anti-CD44v7 significantly downregulated CD80 in dendritic cells, thus inhibiting a critical second signal for naive T-cell activation. The apoptotic signal was mediated via the intrinsic mitochondrial pathway with decreased Bcl-2 and increased 7A6 (a mitochondrial membrane protein) expression. It was Fas independent and required caspases-3 and -9 activation. The process is highly specific for macrophage activation via CD40. These findings point to a novel mechanism of apoptosis induction in CD patients mediated by CD44v7 ligation.  相似文献   

18.
Using a specific enzyme-linked immunosorbent assay, IL-10 concentrations were measured in serum from 62 patients with ulcerative colitis (UC), 43 with Crohn's disease (CD), 25 with other colitides, and 44 normal control subjects. Serum IL-10 concentrations were increased in patients with active UC but not in those with active CD when compared with normal control subjects. A time course study showed that in patients with UC and CD, serum concentrations of IL-6 and C-reactive protein increased during the acute phase and returned to normal as patients go into remission. Notably, serum IL-10 concentrations increased during the phase of disease resolution and declined thereafter regardless of the treatment modality. Gel filtration analysis indicated that IL-10 circulated predominantly as a dimer. In conclusion, this study shows that serum IL-10 is increased during disease recovery in patients with inflammatory bowel disease, and may be a helpful marker in monitoring disease status.  相似文献   

19.
Ulcerative colitis and Crohn's disease are the two major forms of inflammatory bowel disease (IBD). A series of reports have hypothesized interplay of genetic and environmental factors in the pathogenesis of IBD. Polymorphism in the mannan-binding lectin-2 (MBL-2) gene is known to affect the structural assembly and function thereby predisposing subjects to various diseases. The present study was designed to evaluate effect of MBL-2 gene polymorphism on MBL levels and function in IBD patients. Genomic DNA was isolated from blood samples collected from 157 ulcerative colitis, 42 Crohn's disease and 204 control subjects. Genotyping for different polymorphic sites at exon1 of MBL-2 gene was performed by refractory mutation system-PCR and amplification followed by restriction digestion (PCR-RFLP). Serum MBL concentration and C4 deposition levels were estimated using ELISA. Mannan-binding lectin-2 genotypic variants were calculated in IBD and healthy controls. The frequency of single nucleotide polymorphisms at codon 54 was significantly higher in ulcerative colitis patients than controls (P?相似文献   

20.
Ulcerative colitis (colitis ulcerosa) is a non-specific inflammatory bowel disease of unknown etiology. The symptoms which are observed in the course of ulcerative colitis are: an increase in the number of leukocytes and blood platelets, an increase in the concentration of IL-6 and anemia. Blood platelets are the key element, linking the processes of hemostasis, inflammation and the repair of damaged tissues. Activation of blood platelets is connected with changes in their shape and the occurrence of the reaction of release. P-selectin appears on the surfaces of activated blood platelets and the concentration level of soluble P-selectin increases in the blood plasma. The aim of this study was to define whether the increased number of blood platelets in patients with ulcerative colitis accompanies changes in their activation and morphology. A total of 16 subjects with ulcerative colitis and 32 healthy subjects were studied. Mean platelet count, morphological parameters of platelets and MPC were measured using an ADVIA 120 hematology analyzer. Concentrations of sP-selectin and IL-6 in serum were marked by immunoassay (ELISA). MPC, concentration of sP-selectin and IL-6 were significantly higher in subjects with ulcerative colitis compared to those in the healthy group. There was a decrease of MPV in patients with ulcerative colitis, which is statistically significant. Chronic inflammation in patients with ulcerative colitis causes an increase in the number of blood platelets, a change in their morphology and activation. Decreased MPV value reflects activation and the role blood platelets play in the inflammatory process of the mucous membrane of the colon. A high concentration of sP-selectin, which is a marker of blood platelet activation, demonstrates their part in the inflammatory process. The increase in the concentration of sP-selectin correlated positively with the increase in concentration of IL-6. This is why it may be a useful marker of the activity of colitis ulcerosa.  相似文献   

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