Chronic Inflammatory Enteropathy Research Articles

Measurement and clinical applications of C-reactive protein in gastrointestinal diseases of dogs.

C‐reactive protein (CRP) is a positive acute‐phase protein, serum concentrations of which increase nonspecifically in response to inflammatory processes of the dog. As such, it can aid in the identification of inflammatory disease and, maybe more importantly, the objective monitoring of disease progression. In dogs, CRP is frequently used to evaluate dogs with gastrointestinal diseases, such as chronic inflammatory enteropathies (also termed idiopathic inflammatory bowel disease), acute pancreatitis, canine parvovirus infection, hepatic disease, acute abdomen, and protein‐losing enteropathy. The diversity of the assays available to measure CRP in dogs is nearly as numerous as the diseases in which serum concentrations of this protein are increased. Assay methodologies include laser nephelometric immunoassays, enzyme‐linked immunosorbent assays, immunoturbidimetric assays, and time‐resolved immunofluorometric assays. While many of these assays are acceptable for clinical use in the dog, the same assay and analyzer should be used to measure a patient's CRP concentration longitudinally. By looking at the uses of CRP in human gastroenterology, including reducing the duration of antibiotic therapy, the veterinary profession can gain insight into novel ways in which serum CRP concentration measurements might be applied in veterinary medicine in the future.

Faecal proteomics in the identification of biomarkers to differentiate canine chronic enteropathies

Canine chronic enteropathy (CCE) is a collective term used to describe a group of idiopathic enteropathies of dogs that result in a variety of clinical manifestations of intestinal dysfunction. Clinical stratification into food-responsive enteropathy (FRE) or non-food responsive chronic inflammatory enteropathy (CIE), is made retrospectively based on response to treatments. Faecal extracts from those with a FRE (n = 5) and those with non-food responsive chronic inflammatory enteropathies (CIE) (n = 6) were compared to a healthy control group (n = 14) by applying TMT-based quantitative proteomic approach. Many of the proteins with significant differential abundance between groups were pancreatic or intestinal enzymes with pancreatitis-associated protein (identified as REG3α) and pancreatic M14 metallocarboxypeptidase proteins carboxypeptidase A1 and B identified as being of significantly increased abundance in the CCE group. The reactome analysis revealed the recycling of bile acids and salts and their metabolism to be present in the FRE group, suggesting a possible dysbiotic aetiology. Several acute phase proteins were significantly more abundant in the CCE group with the significant increase in haptoglobin in the CIE group especially notable. Further research of these proteins is needed to fully assess their clinical utility as faecal biomarkers for differentiating CCE cases. SignificanceThe identification and characterisation of biomarkers that differentiate FRE from other forms of CIE would prove invaluable in streamlining clinical decision-making and would avoid costly and invasive investigations and delays in implementing effective treatment. Many of the proteins described here, as canine faecal proteins for the first time, have been highlighted in previous human and murine inflammatory bowl disease (IBD) studies initiating a new chapter in canine faecal biomarker research, where early and non-invasive biomarkers for early clinical stratification of CCE cases are needed. Pancreatitis-associated protein, pancreatic M14 metallocarboxypeptidase along with carboxypeptidase A1 and B are identified as being of significantly increased abundance in the CCE groups. Several acute phase proteins, were significantly more abundant in the CCE group notably haptoglobin in dogs with inflammatory enteropathy. The recognition of altered bile acid metabolism in the reactome analysis in the FRE group is significant in CCE which is a complex condition incorporating of immunological, dysbiotic and faecal bile acid dysmetabolism. Both proteomics and immunoassays will enable the characterisation of faecal APPs as well as other inflammatory and immune mediators, and the utilisation of assays, validated for use in analysis of faeces of veterinary species will enable clinical utilisation of faecal matrix to be fully realised.

The Use of Ascophyllum nodosum and Bacillus subtilis C-3102 in the Management of Canine Chronic Inflammatory Enteropathy: A Pilot Study.

Simple SummaryThe development of novel, safe and effective therapies is highly desired for managing diseases requiring long-term use of drugs endowed with side effects. In the present investigation, we aimed to assess the impact of gut microbiota modulation strategies, i.e., the brown seaweed Ascophyllum nodosum and/or the probiotic microorganism Bacillus subtilis C-3102, in dogs diagnosed with Canine Chronic Inflammatory Enteropathy. The tested agents were administered on top of a hydrolysed protein diet, in a step-up fashion at 30-day intervals, with faecal collection and clinical evaluation of disease severity being performed before study initiation as well as at the end of each treatment phase. Neither Ascophyllum nodosum, nor its association with Bacillus subtilis C-3102, were able to significantly alleviate clinical signs and augment bacterial richness within the study population. Notwithstanding, increased numbers of beneficial carbohydrate-fermenting bacteria, alongside with higher amounts of faecal acetate were recorded, suggesting a potentially positive effect on gut health.The aim was to assess the effects of Ascophyllum nodosum (AN) with/without Bacillus subtilis C-3102 as alternative treatments for Chronic Inflammatory Enteropathy (CIE) of dogs. Fourteen CIE patients, which had received the same control (CTR) diet, were enrolled to serially receive three diets: (1) hydrolysed protein (HP) diet; (2) 4.0% AN supplemented HP (HPA) food, (3) HPA diet fortified with 125 billion B. subtilis C-3102 spores/10 kg body weight (HPAB diet). Clinical outcome was assessed by Canine Inflammatory Bowel Disease Activity Index (CIBDAI), whereas gut microbiota compositional variations were investigated via 16S rRNA gene analysis, and faecal fermentation end-products by liquid chromatography. Higher abundances of the Ruminococcaceae and Rikenellaceae families were shown in HPA relative to CTR treatment, with Bacillus genus being differentially abundant on HPAB diet. Concentrations of acetate were higher (p < 0.05) in dogs fed HPA compared to CTR diet, and amounts of isovalerate and isobutyrate were greater (p < 0.05) in HPA compared to HP food. A tendency for higher amounts of faecal butyrate was found for the HPAB treatment (p = 0.06). Comprehensively, while displaying potentially positive effects on faecal fermentations, the tested substances failed to improve CIBDAI scores and microbial richness in CIE dogs.

Electrolyte imbalances in dogs with chronic inflammatory enteropathies

Inflammatory bowel diseases (IBD) in humans are associated with electrolyte shifts and diarrhea. Chronic inflammatory enteropathies (CIE) in dogs produce inflammatory lesions usually located more diffusely throughout the gastrointestinal tract. The prevalence of electrolyte imbalances in canine CIE is unknown. We retrospectively evaluated serum electrolyte (Na+, Cl−, corrected Cl−, and K+) concentrations in 37 dogs with CIE.Hypokalemia was the most frequent electrolyte abnormality, affecting 7 (19%) CIE dogs and with no difference between food-responsive and immunosuppressant-responsive (IRE) cases. Hyponatremia was less common (14%) and predominantly seen with IRE; serum Na+ concentration correlated with the severity of diarrhea and duodenal histologic lesions. Hypo- (5%) and hyperchloridemia (11%) were also detected.Electrolyte imbalances occur with equal frequency in canine CIE and human IBD. Increased K+ secretion might exceed compromised Na+/Cl− absorption or K+ shifts might be more pronounced in canine CIE. Therefore, the mechanisms underlying CIE-associated diarrhea warrant further research.

Concordance of the Histopathologic Diagnosis of Concurrent Duodenal and Ileal Biopsy Specimens in Dogs.

Simple SummaryCanine chronic inflammatory enteropathy (CIE) is a gastrointestinal (GI) inflammatory condition that requires histopathology of intestinal biopsies for definitive diagnosis. This can be performed endoscopically or surgically; with the former being more common as it is less invasive. In recent years, research has identified that different types of inflammatory disease and histologic severity can exist at different locations within the GI tract, known as discordance. There is a lack of understanding of the clinical impact of lesion oversight in dogs with discordant biopsies between locations. Therefore, current recommendations are to procure endoscopic biopsies from both the upper intestinal (stomach and duodenum) and lower small intestinal tract (ileum) when possible. The rate of discordance between different GI locations has not been assessed in dogs with non-inflammatory enteropathies, i.e., neoplastic etiology, nor compared between endoscopic and surgically collected biopsy specimens. Here, we report that the rate of discordance between the duodenum and ileum in CIE is similar between endoscopic biopsy and surgical biopsy specimens and confirm that discordance between upper and lower GI biopsies exist for small-cell lymphoma. There were no clinicopathologic variables that were correlated with discordance. We conclude that for all dogs with chronic GI signs, concurrent duodenal and ileal biopsies should be performed.Histopathologic discordance between gastrointestinal (GI) locations in canine chronic inflammatory enteropathy (CIE) has prompted recommendations to biopsy both the duodenum and ileum, while further evaluation is required for non-CIE. We aimed to determine the concordance of histopathologic diagnosis between duodenal and ileal endoscopic or full-thickness biopsy specimens for all dogs with CIE and GI neoplasia and to assess the association between histopathologic discordance between GI locations with clinicopathologic variables. Seventy-nine dogs were eligible, with endoscopic (74) or full-thickness (5) biopsy specimens. Clinicopathological data were recorded for all dogs. Concordance of histopathologic diagnosis was retrospectively assessed for concurrent duodenal and ileal biopsy specimens by a single board-certified veterinary pathologist using the modified World Small Animal Veterinary Association (WSAVA) Gastrointestinal Standardization Group guidelines. Sixty-seven dogs were diagnosed with CIE and 5 with enteric-associated T-cell lymphoma-2 (EATL-2). Concordance of histologic diagnosis between duodenal and ileal sites was similar between endoscopic (73.0%) and full-thickness (80.0%) biopsy groups. For the CIE cases, lymphoplasmacytic enteritis had the highest concordance (73.0%) and eosinophilic enteritis the least (16.7%). Of the 5 neoplastic cases, 5/5 (100%) were present at the duodenum but only 3/5 (60%) in the ileum. No clinicopathologic variables demonstrated a statistically significant association with discordance. We conclude that the level of discordance necessitates concurrent biopsy of both duodenum and ileum in all dogs with chronic GI signs. The rate of EATL-2 was lower than rates reported for cats.

Chronic enteropathies in cats - diagnostic and therapeutic approach

Chronic enteropathies are characterized by persistent or recurrent gastrointestinal signs including vomiting, diarrhoea, weight loss, anorexia and lethargy for a minimum duration of 3 weeks. Diagnosis is by excluding other disease processes and includes faecal examinations, blood screenings (e. g., thyroidal, pancreatic, liver dysfunctions, investigation for infectious diseases, vitamin B12 status), diagnostic imaging, histopathological evaluation using biopsies from several different gastrointestinal segments and the response to therapeutic trials. Chronic inflammatory enteropathies are classified as food-responsive enteropathy (FRE), antibiotic-responsive enteropathy (ARE), immunosuppressant-responsive or, similarly -refractory enteropathy (IRE). Small-cell (low-grade) alimentary lymphoma (LGAL), a crucial differential diagnosis, is predominantly seen in older cats. The feline chronic enteropathy activity index (FCEAI), a clinical scoring system, was established to objectively assess the severity of clinical illness and to evaluate the response to treatment. In general, the prognosis depends on the underlying aetiology. Cats diagnosed with FRE typically have a good long-term prognosis with adequate dietary management. The response to treatment varies in cats with IRE, with same cats experiencing frequent relapses of clinical signs and still others being non-responsive to treatment. Prognosis for LGAL, with adequate treatment, is usually fair to good (median survival time 510-704 days).

Immunosuppressant-Responsive Enteropathy and Non-Responsive Enteropathy in Dogs: Prognostic Factors, Short- and Long-Term Follow Up.

Simple SummaryChronic intestinal inflammation in dogs is a challenging disease to manage. Most studies about prognostic factors and follow-up data are only available for small populations or with short-term follow-up. The aim of this study of 165 dogs with chronic intestinal inflammation was to identify clinical and haematological factors associated with mortality, clinical response and relapse, with long-term follow-up. Nine per cent of dogs did not respond to therapy at 1 month follow-up. Most dogs with chronic intestinal inflammation had a good clinical course in most cases, and the non-response or relapse rate was 9–11%. A reduction of body condition (loss of weight), lower serum albumin concentration and presence of lacteal dilatation on intestinal histology at diagnosis were identified as factors associated with a decreased response rate, higher mortality and lower chance of achieving long-term remission.A multicentre prospective study was performed to assess whether clinical, hematobiochemical, endoscopic and histopathological parameters were associated with mortality, clinical response and relapse of disease in short- and long-term follow-up of a total of 165 dogs with chronic inflammatory enteropathy, of which 150 had immunosuppressant responsive enteropathy (IRE), and 15 had non-responsive enteropathy (NRE) dogs. Clinical severity (CCECAI) was evaluated from presentation (T0) to 18 months (T18) from diagnosis. T0 body condition score (BCS), selected haematological parameters and endoscopic and histopathological scores were evaluated. Presence/absence of histopathological duodenal lesions was recorded. Responders were evaluated using CCECAI at T1. Relapse was evaluated from T3 to T18. Long-term responders included dogs who responded at T1 and showed no relapse. Dogs were divided into responders/non-responders, survivors/non-survivors and relapsed/non-relapsed. At T1, 15/165 dogs (9%) were considered NRE. Sixteen dogs (11%) were considered relapsed at T3, 8% at T6 and 10% at T12, and none of 96 dogs relapsed at T18. NREs showed significantly lower BCS than IREs. Non-survivors showed a significantly lower serum albumin concentration and BCS than survivors. Non-responders, relapsed or non-survivors had higher presence of lacteal dilatation compared to long-term responders. Dogs with IRE showed a good clinical course with a low relapse rate, with only a few dogs in the NRE group. Reduction of BCS, albumin and lacteal dilatation at diagnosis may be considered negative prognostic factors for response, mortality and long-term disease remission.

The Impact of Chronic Inflammatory Enteropathy on Dogs' Quality of Life and Dog-Owner Relationship.

This research was aimed at evaluating the impact of canine chronic enteropathies on dogs’ quality of life (QoL), their behavior, and owner–dog relationship. Forty-four dogs suffering from primary chronic enteropathies were assessed on the first visit with a veterinary gastroenterologist and on the first follow-up visit using a 1–10 visual scale to evaluate five features of QoL, the Canine Chronic Enteropathy Clinical Activity Index, the Lexington Attachment to Pet Scale, and the Canine Behavioral Assessment and Research Questionnaire. They were compared to a control group of 49 healthy dogs and to a group of 50 dogs suffering from cancer. QoL and severity of enteropathy were negatively associated; enteropathic dogs on the first visit had a lower QoL than healthy dogs for all features and a lower general QoL than cancer patients; enteropathic dogs on the follow-up visit improved significantly for general QoL, health QoL, and interaction QoL. Higher levels of attachment between the owner and the dog were obtained for dogs affected by chronic enteropathies. Finally, dogs showed higher scores for separation-related behaviors and contact/attention behaviors on the first visit than on the subsequent follow-up. As in human medicine, chronic enteropathies have a strong negative impact on dogs.

PetSavers interview

Aarti Kathrani is currently working on the PetSavers-funded study ‘Defining the duodenal mycobiota in dogs with chronic enteropathy’. She has also just been awarded a new PetSavers clinical research project grant for a study entitled ‘The characterization and clinical significance of intestinal fibrosis in cats with chronic inflammatory enteropathy’.

Upregulation of signal transducer and activator of transcription 3 in dogs with chronic inflammatory enteropathies.

BackgroundIn inflammatory bowel disease (IBD) in humans, phosphorylated signal transducer and activator of transcription 3 (pSTAT3) is upregulated in mucosal epithelial cells and correlates with clinical severity.Hypothesis/ObjectiveTo investigate the expression pattern of pSTAT3 in the mucosa of dogs with chronic inflammatory enteropathy (CIE) and explore correlations between its expression and clinical and histopathological severity scoring.AnimalsTwenty‐eight canine CIE patients grouped into food‐responsive enteropathy (FRE; 9), steroid‐responsive enteropathy (SRE; 10), and protein‐losing enteropathy (PLE; 9). Ten healthy beagle dogs served as controls (CO).MethodsRetrospective case control study. Immunohistochemistry was used to detect pSTAT3 in canine duodenal mucosa samples.ResultsCompared to CO, SRE (P < .001) and PLE (P < .001) dogs had significantly higher pSTAT3 expression in the villus epithelium. The SRE group had a significantly higher expression in the villus lamina propria (VLP) compared to controls (P = .009). In the crypt epithelium (CE), all CIE dogs had significantly higher pSTAT3 expression (FRE, P = .002; SRE, P = .003; PLE, P < .001) compared to CO. In the lamina propria crypt region (CLP), dogs with FRE (P = .04) and SRE (P = .03) had significantly upregulated pSTAT3 compared to controls. A positive correlation was found between canine chronic enteropathy clinical activity index (CCECAI) scoring and pSTAT3 expression for both epithelial (rho = .541; P < .001) and crypt regions (rho = .32; P = .02).Conclusions and Clinical ImportancepSTAT3 is upregulated in CIE in dogs, correlates with clinical severity, and may be helpful as a clinical marker in dogs with CIE.

Coagulation status, fibrinolysis, and platelet dynamics in dogs with chronic inflammatory enteropathy.

BackgroundCoagulation status is poorly understood in dogs with chronic inflammatory enteropathy (CIE). Fibrinolytic activity and platelet dynamics have not been evaluated in CIE dogs.ObjectivesTo assess coagulation status and fibrinolysis in normoalbuminemic CIE dogs (CIE‐N) and CIE dogs with protein‐losing enteropathy (CIE‐PLE) compared to healthy controls (HC). To evaluate thromboelastography (TEG) variable differences between groups and for correlations with clinicopathologic data. To report platelet dynamics in CIE dogs.AnimalsTwenty‐five client‐owned dogs with CIE (n = 16 CIE‐N; n = 9 CIE‐PLE); 14 HC beagle dogs.MethodsAll dogs had tissue factor + tissue plasminogen activator TEG. Nine of 25 CIE dogs had whole blood impedance platelet aggregometry. The TEG variables and coagulation data were compared between all CIE vs HC dogs, CIE‐N dogs vs HC, and CIE‐PLE dogs vs HC. Clinicopathologic and coagulation data were available for CIE dogs and assessed for correlation to TEG variables.ResultsDogs with CIE had higher maximum amplitude (MA; P < .001), longer clot lysis times (CLTs; P < .001), lower % lysis after 30 minutes (LY30; P < .001), and % lysis after 60 minutes (LY60; P < .001) compared to HC, suggesting hypercoagulability and hypofibrinolysis. When separated out, both CIE‐N and CIE‐PLE dogs had higher MA, longer CLT, and lower LY30 and LY60 compared to HC. Serum albumin and 25‐hydroxyvitamin D (25[OH]D) concentrations, and plasma antithrombin and fibrinogen concentrations moderately correlated with MA.Conclusions and Clinical ImportanceNormoalbuminemic and hypoalbuminemic CIE dogs were considered hypercoagulable based on TEG compared to HC. Some CIE dogs displayed hypofibrinolytic phenotypes on TEG.

Dysregulation of gastrointestinal RAGE (receptor for advanced glycation end products) expression in dogs with chronic inflammatory enteropathy

The pathogenesis of chronic inflammatory enteropathies (CIE) in dogs involves dysregulated innate immune responses. The receptor for advanced glycation end products (RAGE), a pattern recognition receptor, plays a role in chronic inflammation. Abrogation of proinflammatory RAGE signaling by ligand binding (e.g., S100/calgranulins) to soluble RAGE (sRAGE) might also be a novel therapeutic avenue. Serum sRAGE levels are decreased in canine CIE, but gastrointestinal tissue RAGE expression has not been investigated in dogs. Thus, the study aimed to evaluate the gastrointestinal mucosal RAGE expression in dogs with CIE. Further, the potential binding of RAGE to canine S100/calgranulin ligands was investigated.Epithelial RAGE expression was quantified in gastrointestinal (gastric, duodenal, ileal, and colonic) biopsies from 12 dogs with CIE and 9 healthy control dogs using confocal laser scanning microscopy. RAGE expression was compared between both groups of dogs and was tested for an association with patient characteristics, clinical variables, histologic lesion severity, and biomarkers of extra-gastrointestinal disease, systemic or gastrointestinal inflammation, function, or protein loss. Statistical significance was set at p < 0.05. RAGE:S100/calgranulin binding was assessed by immunoassay and electrophoretic techniques.RAGE expression was detected in all 59 biopsies from diseased and healthy control dogs evaluated. Epithelial RAGE expression in the duodenum and colon was significantly higher in dogs with CIE than in healthy controls (p < 0.04). Compared to healthy controls, RAGE expression in dogs with CIE also tended to be higher in the ileum but lower in the stomach. A slight (statistically not significant) shift towards more basal intestinal epithelial RAGE expression was detected in CIE dogs. Serum sRAGE was proportional to epithelial RAGE expression in the duodenum (p < 0.04), and RAGE expression in the colon inversely correlated with biomarkers of protein loss in serum (both p < 0.04). Several histologic morphologic and inflammatory lesion criteria and markers of inflammation (serum C-reactive protein and fecal calprotectin concentration) were related to epithelial RAGE expression in the duodenum, ileum, and/or colon. in vitro canine RAGE:S100A12 binding appeared more pronounced than RAGE:S100A8/A9 binding.This study showed a dysregulation of epithelial RAGE expression along the gastrointestinal tract in dogs with CIE. Compensatory regulations in the sRAGE/RAGE axis are an alternative explanation for these findings. The results suggest that RAGE signaling plays a role in dogs with CIE, but higher anti-inflammatory decoy receptor sRAGE levels paralleled RAGE overexpression. Canine S100/calgranulins were demonstrated to be ligands for RAGE.

Coeliac Disease Etiology and Pathogenesis

Coeliac disease is a chronic inflammatory autoimmune enteropathy that affects around 1% of people worldwide. It is caused by ingestion of gluten products in people who are genetically predisposed. The pathogenesis involves multifactorial factors of genetic, gluten exposure, and environmental triggers. HLA-DQ2 and HLA-DQ8 are the main responsible genes that contribute to the development of coeliac disease. Both innate and adaptive immune plays role in the pathogenesis. In this article, we will review the causes and pathogenesis of coeliac disease development.

Correlation of minimally invasive imaging techniques to assess intestinal mucosal perfusion with established markers of chronic inflammatory enteropathy in dogs.

BackgroundMinimally invasive diagnostic imaging techniques to detect intestinal inflammation in dogs are lacking. Contrast‐enhanced ultrasound (CEUS) and endoscopic narrow band imaging‐like endoscopy (Storz Professional Image Enhancement System [SPIES]) might allow quantification of intestinal mucosal perfusion and microvessel density in chronic inflammatory enteropathy (CIE) of dogs.Hypothesis/ObjectivesMarkers of mucosal perfusion as determined by CEUS and SPIES endoscopy are potentially useful diagnostic markers to help characterize CIE and correlate with histological inflammation type and severity.AnimalsThirty client‐owned dogs diagnosed with CIE at a referral hospital were prospectively enrolled.Materials and MethodsData from CEUS, SPIES, and white light (WL) endoscopy were correlated with World Small Animal Veterinary Association (WSAVA) endoscopy and histology scores and vessel density as determined by immunohistochemistry for von Willebrand factor (vWF). Automated linear modeling was used to determine predictors of endoscopic and histologic severity.ResultsDuodenal histology correlated with SPIES data (area percentage value, rho = 0.424, P = .04). White light endoscopy parameters correlated with SPIES parameters in the duodenum. Colonic histology correlated positively with CEUS, whereas colonic CEUS parameters correlated inversely with vWF expression. Several duodenal parameters combined predicted duodenal histology scores to a level of 73.4%. For the colon, 2 parameters contributed more than others to 73.1%.Conclusion and Clinical ImportanceMinimally invasive CEUS and SPIES appear feasible to assess intestinal perfusion in CIE. Use of SPIES endoscopy may be promising for assessing small intestinal inflammation, whereas CEUS could be used to assess colonic perfusion and inflammation. Both techniques need to be investigated further for their clinical utility.

Acute Ulcerative Enterocolitis With Severe Protein Loss Due to Mucosal Invasion With Enterococcus spp. in a Dog With Exocrine Pancreatic Insufficiency: A Case Report

We describe an unusual case of severe acute protein-losing enteropathy in a dog, which presented with a systemic inflammatory response syndrome. This dog's condition could not be categorized as any well-known canine intestinal condition. Instead, components of several enteropathies like acute hemorrhagic diarrhea syndrome (AHDS), chronic inflammatory enteropathy (CIE), and ulcerative and granulomatous colitis were present. Thorough investigations identified concurrent exocrine pancreatic insufficiency (EPI) and hypocobalaminemia. On histopathology, marked diffuse chronic-active ileitis and ulcerative colitis with fibroplasia and neovascularization were present. Intestinal biopsy cultures identified E.coli and multiresistant Enterococcus spp. The latter was identified as mucosally invasive using fluorescent in situ hybridization (FISH). Protracted clinical signs following the acute presentation required intensive care including enteral and parenteral feeding for a successful outcome, but eventually stabilized with antibiotics and immunosuppressive doses of glucocorticoids. This case highlights a potentially previously unrecognized condition, suspected to be a form of CIE manifesting acutely after bacterial mucosal invasion. In this case, this might have been facilitated by EPI-induced dysbiosis. The use of FISH and mucosal culture in this context provided important clinical information and should be considered more frequently in CIE and non-responsive AHDS.

Association between serum soluble receptor for advanced glycation end-products (RAGE) deficiency and severity of clinicopathologic evidence of canine chronic inflammatory enteropathy.

Innate immunity plays a central role in the pathogenesis of chronic inflammatory enteropathies (CIE) in dogs, and further evaluation of the innate immune receptor for advanced glycation end-products (RAGE) is warranted. We measured serum concentrations of decoy receptor soluble RAGE (sRAGE) in 102 dogs diagnosed with CIE, and evaluated relationships with clinical disease severity, histologic lesion severity, concentrations of serum C-reactive protein (CRP), and serum and fecal calprotectin, S100A12, and alpha1-proteinase inhibitor (α1PI). Serum sRAGE levels were not associated with clinical disease activity, serum CRP, serum and fecal α1PI, calprotectin, or S100A12 concentrations. Microscopic lesions in the duodenum were more severe in dogs with serum sRAGE concentration ≤ 340 ng/L (p = 0.013). Serum sRAGE levels were weakly and inversely correlated with the severity of lymphoplasmacytic infiltration in the gastric antrum and duodenum, and with crypt dilation and the neutrophilic infiltrate in the duodenum, in univariate analysis (all p < 0.05), but none of the correlations remained statistically significant after correction for multiple comparisons. Our study confirms that CIE in dogs is associated with decreased serum sRAGE concentrations, suggesting a dysregulated sRAGE/RAGE axis.

A19 NOVEL HLA-DQ2 TRANSGENIC MICE DEVELOP GLUTEN-IMMUNOPATHOLOGY FOLLOWING GLUTEN SENSITIZATION

Abstract Background Celiac disease (CeD), an autoimmune and chronic inflammatory enteropathy triggered by the ingestion of gluten, is associated with HLA-DQ2 (~90%) and, to a lesser extent, HLA-DQ8. We previously characterized a humanized mouse model of gluten sensitivity that expresses the HLA-DQ8 allele, and that develops mild innate and adaptive immune pathways related to DQ8+ CeD patients. Gluten peptides recognized in the context of DQ2 differ from those bound to DQ8 molecules and homozygous carriage of HLA-DQ2 provides higher risk for CeD development. Thus, characterization of a transgenic HLA-DQ2 model would allow for the investigation of disease pathways that affect the majority of celiac patients. Aims Our aim was to determine gluten-immune responses and small intestinal pathology in C57BL/6 mice humanized with the HLA DR3-DQ2 gene. Methods To break oral tolerance to gluten, DR3-DQ2 mice were orally sensitized with gliadin (5mg/mL) and cholera toxin (CT; 2.5mg/mL) before being challenged with gluten (10mg/mL) for three weeks. Non-sensitized DR3-DQ2 controls mice received CT and a sham challenge. To determine the effects of long-term exposure to gluten, gliadin sensitized DR3-DQ2 mice were placed on a gluten-containing diet for twelve weeks. Controls were given CT and remained on a gluten-free diet. Pathology was evaluated by CD3+ intraepithelial lymphocytes (IELs) counts; villus-crypt (V/C) ratios. Gluten-induced immune responses were evaluated by anti-tissue transglutaminase-2 (tTG) and anti-gliadin antibodies, inflammatory gene expression by Nanostring Technology, and CD4+ T cell proliferation using flow cytometry. Intestinal permeability was measured in vitro by Ussing Chamber. Results DR3-DQ2 mice that were sensitized and challenged with gluten for three weeks had higher IEL counts, lower V/C ratios, higher anti-gliadin and tTG antibodies, which are used in the serological diagnosis of the disease. Gluten sensitized mice also has higher expression of pro-inflammatory genes, and an induction of gluten specific T cells, but no changes in permeability compared to control mice. DR3-DQ2 mice given a gluten-containing diet for 12 weeks also had higher IEL counts, lower V/C ratios, and higher anti-gliadin and tTG antibodies, but had no changes in permeability compared to controls. Conclusions These results indicate that mice humanized with the HLA DR3-DQ2 gene show innate and gluten-specific immune responses following sensitization. Thus, mice expressing HLA-DQ2 represents a novel model of gluten sensitivity that can be used to investigate celiac disease pathways related to gluten peptide repertoire that binds to DQ2 MHC class II, encoded by the HLA gene expressed by the majority of celiac patients. Supported by CIHR to EFV and OGS to AVC Funding Agencies CIHROGS

Bacterial Biogeography of the Colon in Dogs With Chronic Inflammatory Enteropathy.

The intestinal microbiota is believed to play a role in the pathogenesis of inflammatory bowel disease in humans and chronic inflammatory enteropathy (CIE) in dogs. While most previous studies have described the gut microbiota using sequencing methods, it is fundamental to assess the spatial distribution of the bacteria for a better understanding of their relationship with the host. The microbiota in the colonic mucosa of 22 dogs with CIE and 11 control dogs was investigated using fluorescence in situ hybridization (FISH) with a universal eubacterial probe (EUB338) and specific probes for select bacterial groups. The number of total bacteria labeled with EUB338 probe was lower within the colonic crypts of dogs with CIE compared to controls. Helicobacter spp. and Akkermansia spp. were decreased on the colonic surface and in the crypts of dogs with CIE. Dogs with CIE had increased number of Escherichia coli/Shigella spp. on the colonic surface and within the crypts compared to control dogs. In conclusion, the bacterial microbiota in the colonic mucosa differed between dogs with and without CIE, with depletion of the crypt bacteria in dogs with CIE. The crypt bacterial species that was intimately associated with the host mucosa in control dogs was composed mainly of Helicobacter spp.

What are the potential biomarkers that should be considered in diagnosing and managing canine chronic inflammatory enteropathies?

Chronic inflammatory enteropathies in dogs are characterized by persistent or recurrent gastrointestinal signs that last for more than 3 weeks. Despite unclear etiopathogenesis, it is considered that a genetic predisposition associated with environmental factors, such as dietary antigens and intestinal microbiota, might induce an abnormal immune response in the host. The diagnosis of this condition requires full investigation in order to exclude all other possible causes. Currently, the observation of clinical signs associated with histopathologic evaluation and systematic therapeutic trials is the gold standard for the diagnosis of chronic enteropathies. Furthermore, diagnosis, monitoring the disease progression, and treatment response evaluation can be exhausting, since this whole process is time-consuming, costly, and partially invasive. Therefore, biomarkers appear as non-invasive tools, which can be useful in evaluating gastrointestinal function, identifying the presence of the disease and assessing its natural progression, monitoring gastrointestinal inflammation, predicting response to treatment, and clinical outcomes. Over the past decade, several studies were conducted in order to explore the clinical utility of biomarkers. Thus, the aim of this dissertation is to provide an overview of the biomarkers considered relevant in the diagnosis and management of dogs with chronic inflammatory enteropathies. The biomarkers addressed in this study may be serological, present in urine and feces, or even tissue-derived. This study argues that biomarkers, in particular calprotectin and calgranulin C, have great potential to be used in clinical practice in the diagnosis and management of affected dogs. However, a single biomarker cannot assuredly predict disease severity, progression, response to treatment, and clinical outcomes. Therefore, in order to achieve greater accuracy, it would be beneficial if these tools are used in conjunction with contemporary ones. Future research is needed with the aim to better determine the usefulness of these tools in chronic inflammatory enteropathies in dogs.

Ki-67/CD3 ratio in the diagnosis of chronic inflammatory enteropathy in dogs.

BackgroundT cells play a key role in the pathogenesis of chronic inflammatory enteropathy (CIE) in dogs. Cluster of differentiation 3 (CD3) antigen serves as a marker for T cells. In human medicine, Ki‐67 is an indicator for cell growth but there are only a few studies in dogs with CIE.ObjectiveTo investigate Ki‐67 in relation to T cells as a marker for CIE in dogs.AnimalsEleven dogs with CIE and 6 healthy beagle controls (CO).MethodsRetrospective case‐control study. Dogs were clinically assessed by the Canine Chronic Enteropathy Clinical Activity Index (CCECAI). Duodenal mucosal biopsy samples were endoscopically obtained for histopathologic examination by means of the World Small Animal Veterinary Association score. Double‐labeled immunofluorescence was used to investigate colocalization of Ki‐67 and CD3 in epithelium and lamina propria (LP) of villi and crypts.ResultsDogs with CIE had significantly higher clinical score (median, 5.0; interquartile range [IQR], 3‐7) compared to CO (all 0; P < .001). The Ki‐67/CD3 double‐positive cells were significantly increased in the LP of the crypt region of CIE dogs (0.63 cells/mm2; IQR, 0‐0.54) versus CO (0.08 cells/mm2; IQR, 0‐0.26; P = .044). A significant correlation was found between CCECAI and the Ki‐67/CD3 ratio in the LP of the crypt region (r = 0.670; P = .012) in dogs with CIE.Conclusions and Clinical ImportanceThe Ki‐67/CD3 ratio is upregulated in the LP crypt region of dogs with CIE and it correlates with clinical severity. Therefore, Ki‐67/CD3 could be a useful tool for detection of CIE.