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BACKGROUND: Inflammatory bowel disease (IBD) is thought to result from a dysregulated interaction between the host immune system and commensal microflora. Toll-like receptors (TLRs) recognize microbe-associated molecular patterns (MAMPs), but their role in enteropathies in dogs is unknown. HYPOTHESIS: That there is a dysregulation of TLRs recognizing bacterial MAMPs in dogs with IBD. ANIMALS: Sixteen healthy beagles and 12 dogs with steroid-treated (ST) and 23 dogs with food-responsive (FR) diarrhea. METHODS: Prospective, observational study. mRNA expression of canine TLR2, 4, and 9 was evaluated by quantitative real-time RT-PCR in duodenal and colonic biopsies obtained before and after standard therapy. Samples from control dogs were taken at necropsy, with additional biopsies of stomach, jejunum, ileum, and mesenteric lymph node in 6 dogs. RESULTS: There were significant differences (P< or = .017) in expression of TLR2, 4, and 9 between the 6 sampled locations in healthy control dogs (lymph node > small intestine > or = colon). Before therapy, ST expressed more mRNA than control dogs for all 3 receptors (P < .05). There were no significant differences between pretreatment and posttreatment values, even though 32/35 dogs improved clinically. No associations were found when comparing receptor mRNA expression with either histology or clinical activity scores. CONCLUSIONS AND CLINICAL IMPORTANCE: Bacteria-responsive TLR2, 4, and 9 are upregulated in duodenal and colonic mucosa in IBD. This might lead to increased inflammation through interaction with the commensal flora. The absence of significant changes after therapy despite clinical improvement might point toward the existence of a genetic predisposition to IBD as described in human IBD.  相似文献   

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Inflammatory bowel disease (IBD) is a common cause of chronic diarrhoea in dogs. In people, specific cytokine patterns attributed to T cell subsets, especially T helper cell [Th]1, Th17 and regulatory T(reg) cells have emerged in IBD. In contrast, no specific involvement of a distinct T cell subset has been described so far in canine IBD. Thus, the aim of the present study was to assess gene expression of signature cytokines in duodenal tissues from 18 German shepherd dogs with IBD (group 1), 33 dogs of other breeds with IBD (group 2) and 15 control dogs (group 3). Relative quantification of IL-17A, IL-22, IL-10, IFNy and TGFβ was performed. Expression of IL-17A was significantly lower in groups 1 and 2 compared to group 3 (p=0.014), but no difference in the expression of IL-22 (p=0.839), IFNγ (p=0.359), IL-10 (p=0.085) or TGFβ (p=0.551) across groups was detected. Thus, no clear evidence for the involvement of Th-17 signature cytokines in canine IBD at the mRNA level could be shown. The contribution of specific T cell subsets to the pathogenesis of canine IBD warrants further investigation.  相似文献   

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The mucosal immune system may play a critical role in the pathogenesis of small intestinal enteropathies. The aim of the current study was to assess mucosal immune cell populations in dogs with inflammatory bowel disease (IBD), idiopathic antibiotic-responsive diarrhea (ARD), and adverse reactions to food (FR). Endoscopic biopsies were performed of the duodenum of dogs with these conditions and from a group of dogs without enteric disease. Additional control samples were collected after death from other dogs that did not have evidence of enteric disease. Immunohistochemistry and computer-aided morphometry were used to assess the distribution of immune cell subsets in both lamina propria and intestinal epithelium. Compared with controls, dogs with ARD had increased numbers of lamina propria immunoglobulin (Ig) A- plasma cells and CD4+ cells. More marked alterations were noted in dogs with IBD, with significant increases in lamina propria IgG+ plasma cells, T cells (CD3+), CD4+ cells, macrophages, and neutrophils, but with reduced mast cell numbers. Increased intraepithelial CD3+ T cells were also present in the dogs with IBD, compared with controls. However, lamina propria and epithelial populations were unaltered in dogs with FR when compared with controls. The altered mucosal immune cell populations observed in dogs with ARD or IBD may reflect an underlying immunologic pathogenesis in these disorders.  相似文献   

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Inflammatory colorectal polyps (ICRPs) in miniature dachshunds are recently recognized as a major cause of large bowel diarrhea in this dog breed in Japan. ICRPs are characterized by the formation of multiple small polyps and a space-occupying large polyp in the colorectal area, and are thought to be a novel form of inflammatory bowel disease (IBD). In humans, specific cytokine patterns attributed to T helper (Th)1, Th17 and regulatory T cells have important roles in the pathogenesis of IBD. Thus, the aim of the present study was to assess the gene expression of cytokines of T cell subsets in the colorectal mucosa from dogs with ICRPs. Colorectal mucosal specimens from 10 dogs with ICRPs and 14 control dogs were used in this study. Interferon (IFN)-γ, interleukin (IL)-4, IL-17A and IL-10 mRNA expression was assessed using quantitative real-time PCR. IL-17A mRNA expression was significantly increased in large polyps compared to small polyps and controls. IFN-γ and IL-10 mRNA expression in large polyps were significantly higher than in controls. There was no significant difference in IL-4 mRNA expression among the three groups. IL-17A is thought to play important roles in the pathogenesis of ICRPs. IL-10 up-regulation could oppose the proinflammatory function of IL-17A.  相似文献   

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Canine sino-nasal aspergillosis is usually caused by Aspergillus fumigatus and is similar to human chronic erosive non-invasive fungal sinusitis. The pathogenesis of the disease is poorly understood. We investigated the nature of the local immune response mounted in canine sino-nasal aspergillosis. Quantitative RT-PCR was carried out on RNA isolated from nasal biopsies from diseased and control dogs, using specific assays designed to amplify mRNA encoding a panel of cytokines and chemokines. Canine sino-nasal aspergillosis was associated with significantly increased expression of mRNA encoding MCP-1, -2, -3 and -4, IL-8, IL-10, IL-18 and TNF-alpha relative to controls (P<0.01) but there was no difference between groups with respect to IL-4, IL-5, IL-6, IL-12, TGF-beta, and eotaxin-2 and -3. The up-regulation of proinflammatory cytokines and chemokines related to the influx of phagocytic cells might account for the localisation of this infection to the upper respiratory tract. The up-regulation of the expression of the immunomodulatory cytokine IL-10 in nasal tissue from affected dogs might be important in limiting the extent of local tissue destruction, but might also account for the fact that infected dogs are generally unable to clear this infection spontaneously.  相似文献   

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The most commonly encountered chronic enteropathies in dogs are inflammatory bowel disease (IBD), food allergies, and small intestinal bacterial overgrowth. Recent research in the field of immunopathogenesis of IBD and food allergy in human beings have made available new therapeutic options with immunomodulatory drugs. However, the mechanisms involved in the pathogenesis of canine IBD and food allergy have not been elucidated so far. Further studies focusing on the immunological dysregulation in the mucosa as well as clinical trials with new therapeutic modalities are needed to improve our knowledge and approach to these chronic diseases in dogs.  相似文献   

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The interaction between fractalkine/CX(3)CL1 and its receptor CX(3)CR1 has been reported to play an important role in various human inflammatory diseases, including inflammatory bowel disease (IBD) mediated by lymphocyte chemoattraction. The objective of this study was to investigate the role of fractalkine and CX(3)CR1 in lymphocyte migration in canine IBD. IBD was diagnosed in 34 dogs, and 19 healthy beagles were used as normal controls. We quantified intestinal mRNA and protein expression of fractalkine and CX(3)CR1 by real-time RT-PCR and ELISA, respectively, and examined the localization of fractalkine in canine intestine by immunohistochemistry. The expression of CX(3)CR1 and surface antigens on peripheral blood mononuclear cells (PBMCs) and intraepithelial lymphocytes (IELs) was analyzed by flow cytometry. Intestinal fractalkine and CX(3)CR1 mRNA was significantly up-regulated in IBD dogs compared with the healthy control dogs. In addition, fractalkine expression on intestinal epithelial cells was significantly increased in the intestinal mucosa of IBD dogs compared with the healthy dogs. CX(3)CR1(+) PBMCs were significantly elevated in IBD dogs and positively correlated with the histopathological severity of IELs infiltration. These CX(3)CR1(+) PBMCs predominantly expressed markers for cytotoxic T cells. Almost all IELs expressed CD3, and the majority of cells expressed CD8 rather than CD4, which was analogous to the CX(3)CR1(+) PBMCs. These results suggest that the fractalkine-CX(3)CR1 interaction may contribute to the pathogenesis of canine IBD through migration of IELs.  相似文献   

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The dog is the main reservoir of Leishmania infantum, the parasite responsible for visceral leishmaniasis in Mediterranean countries. The infection in dogs shows different clinical presentations, from subclinical/asymptomatic to a fully developed disease, depending on the host's immune responses. The Th1/Th2 dichotomy is not clear in the different forms of canine leishmaniasis, since the data available from studies of immunity response in canine leishmaniasis are scarce and fragmented. The present work describes the cytokine expression in peripheral blood mononuclear cells (PBMC) obtained from asymptomatic dogs experimentally infected with L. infantum that present a cellular protective immune response. The results obtained from freshly isolated PBMC showed expressions of TNF-alpha, IL-2, IFN-gamma, IL-10 and IL-18 mRNA, similar to those from non-infected dogs. However, there was almost no expression of IL-4 mRNA detected in the asymptomatic infected dogs compared to the control dogs. Unspecific stimulation with ConA promoted the expression in a greater or lower degree of all the cytokines studied. In vitro stimulation of PBMC with soluble leishmanial antigen (SLA) promoted the expression of IL-2, IFN-gamma, TNF-alpha, IL-18, IL-4, IL-6 and IL-10 mRNA, with the two first being specifically induced. Although both Th1 and Th2 cytokines are produced, cell mediated immunity observed in these L. infantum-infected asymptomatic dogs depended on the preferential expression of Th1 cytokines.  相似文献   

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Intestinal wall thickness is neither a specific nor sensitive ultrasound parameter for detecting intestinal inflammation. We hypothesize that mucosal echogenicity, lymphadenomegaly, and secondary findings of the gastrointestinal tract would be more sensitive and specific markers for detecting and differentiating causes of chronic inflammatory bowel disease in dogs. Fifty-six client-owned dogs with chronic diarrhea and 10 control dogs were examined with two-dimensional, gray-scale ultrasound (time 0, 4, and 10 weeks post therapy) and small intestinal mucosal biopsies were performed at the 0- and 4-week time points. The clinical activity was assessed at each time point using the canine inflammatory bowel disease activity index (CIBDAI). Fifty-one dogs had inflammatory infiltration of the duodenal mucosa and were divided into three groups, food-responsive disease, idiopathic inflammatory bowel disease, and protein-losing enteropathy, based on their response to the different treatments and histology. Two different patterns of increased echogenicity of the mucosa were detected: hyperechoic speckles and hyperechoic striations. A normal, hypoechoic bowel mucosa in dogs with chronic diarrhea had a sensitivity of 80% and a specificity of 81% for the diagnosis of food-responsive disease. Hyperechoic striations had a sensitivity of 75% and a specificity of 96% for dogs with protein-losing enteropathy. Hyperechoic speckles were non-specific for diagnosing inflammatory bowel disease. There was a significant relationship between ultrasound score and CIBDAI at t0, but not following therapy. Mucosal echogenicity may be a better parameter for detecting inflammatory bowel disease than bowel wall thickness in dogs with chronic diarrhea.  相似文献   

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German Shepherd Dogs have an increased incidence of anal furunculosis (AF), which is a disease characterised by inflammation and ulceration of the perianal tissues. Ciclosporin, an immunosuppressive drug, has been successfully used to treat AF, suggesting that the pathogenesis of disease is likely to have an immune-mediated component. Previous research has shown that the cytokine mRNA profile in AF lesions is consistent with T cell-mediated inflammation. The aims of the current study were to quantify IL-2 and IFNgamma mRNA expression in AF biopsies taken before and after treatment with ciclosporin and to compare cytokine expression with lesion severity. Twenty-two dogs with AF were recruited into the study and lesional biopsies were taken prior to ciclosporin therapy. Lesion severity was graded using a visual analogue scale. All dogs were evaluated after 4 weeks of ciclosporin therapy and, in 10 dogs with persistent disease, residual lesions were resected. RNA was extracted from AF-lesional tissue and control perianal tissue samples (n=10), which was used as the template for RT-PCR. Analysis of IL-2 and IFNgamma mRNA expression was performed using real-time PCR. IL-2 and IFNgamma mRNA was consistently detected in pre-treatment AF biopsies and, when quantified, this was significantly increased compared to control tissue (P<0.05). However, no correlation was seen between lesion severity and pre-treatment cytokine mRNA expression. In the ten paired pre- and post-treatment samples, IL-2 mRNA expression was significantly reduced in residual disease tissue following ciclosporin therapy (P=0.013). Treatment with ciclosporin seemed to result in decreased expression of IFNgamma mRNA in AF lesions but this was not statistically significant. In six of the 10 dogs with persistent disease, T cell cytokine mRNA could still be detected in the tissues, suggesting that there was inadequate immunosuppression. The absence of a correlation between T cell cytokine expression and the severity of disease suggests that tissue destruction observed in AF might be a consequence of other inflammatory mediators or downstream effects of T cell activation.  相似文献   

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