Probiotics Restoring the Pattern of Apical Junction Complex Protein (AJC) Expression in the Intestinal Mucosa of Dogs with Inflammatory Bowel Disease

Introduction: The apical junction complex (AJC) plays a significant role in regulating epithelial paracellular permeability. Materials and Methods: We have studied by immunohistochemistry the distribution of tight junction components (claudin-2, occludin) and adherens junction (E-cadherin) proteins in the normal intestinal tract from three control dogs (CD) and from 10 dogs with IBD, before and after a probiotic treatment (VSL#3, VSL Pharmaceuticals, Inc; 450 billion lyophilized bacteria daily for 60 days). Results: In the CD group, occludin-specific labelling was most intense at the epithelial cell AJC and appeared uniformly expressed throughout the epithelium of the small and large intestine, but in the IBD group a weak to absent expression was observed in luminal epithelium and in some intestinal glands of the small intestine. No differences in the distribution or labelling intensity of E-cadherin were observed between normal and affected dogs. In the CD group, claudin-2 was detected in the duodenal epithelium and glands and in the colonic crypt epithelium, decreasing in intensity from the distal to the proximal crypt and becoming barely detectable at the luminal surface of the colon. However, claudin-2 expression was increased in the proximal crypt and luminal epithelium of all dogs with IBD. Conclusions: The observation that the expression and distribution of occludin and claudin-2 were restored after VSL#3 treatment may provide insight into the effects of probiotics on intestinal barrier function

Colonic mucosal and serum expression of microRNAs in canine large intestinal inflammatory bowel disease

Background: Canine inflammatory bowel disease (IBD) is a group of chronic gastrointestinal (GI) disorders of still largely unknown etiology. Canine IBD diagnosis is time-consuming and costly as other diseases with similar signs should be initially excluded. In human IBD microRNA (miR) expression changes have been reported in GI mucosa and blood. Thus, there is a possibility that miRs may provide insight into disease pathogenesis, diagnosis and even treatment of canine IBD. The aim of this study was to determine the colonic mucosal and serum relative expression of a miRs panel in dogs with large intestinal IBD and healthy control dogs. Results: Compared to healthy control dogs, dogs with large intestinal IBD showed significantly increased relative expression of miR-16, miR-21, miR-122 and miR-147 in the colonic mucosa and serum, while the relative expression of miR-185, miR-192 and miR-223 was significantly decreased. Relative expression of miR-146a was significantly increased only in the serum of dogs with large intestinal IBD. Furthermore, serum miR-192 and miR-223 relative expression correlated to disease activity and endoscopic score, respectively. Conclusion: Our data suggest the existence of dysregulated miRs expression patterns in canine IBD and support the potential future use of serum miRs as useful noninvasive biomarkers. © 2020 The Author(s)

Effect of Sample Quality on the Sensitivity of Endoscopic Biopsy for Detecting Gastric and Duodenal Lesions in Dogs and Cats

Background: The quality of histopathology slides of endoscopic biopsies from different laboratories varies, but the effect of biopsy quality on outcome is unknown. Hypothesis: The ability to demonstrate a histologic lesion in the stomach or duodenum of a dog or cat is affected by the quality of endoscopic biopsy samples submitted. More endoscopic samples are needed to find a lesion in poor-quality tissue specimens. Animals: Tissues from 99 dogs and 51 cats were examined as clinical cases at 8 veterinary institutions or practices in 5 countries. Methods: Histopathology slides from sequential cases that underwent endoscopic biopsy were submitted by participating institutions. Quality of the histologic section of tissue (inadequate, marginal, adequate), type of lesion (lymphangiectasia, crypt lesion, villus blunting, cellular infiltrate), and severity of lesion (normal, mild, moderate, severe) were determined. Sensitivity of different quality tissue samples for finding different lesions was determined. Results: Fewer samples were required from dogs for diagnosis as the quality of the sample improved from inadequate to marginal to adequate. Duodenal lesions in cats displayed the same trend except for moderate duodenal infiltrates for which quality of tissue sample made no difference. Gastric lesions in dogs and mild gastric lesions in cats had the same trend, whereas the number of tissue samples needed to diagnose moderately severe gastric lesions in cats was not affected by the quality of tissue sample. Conclusions and Clinical Importance: The quality of endoscopically obtained tissue samples has a profound effect on their sensitivity for identifying certain lesions, and there are differences between biopsies of canine and feline tissues

Effect of Tissue Processing on Assessment of Endoscopic Intestinal Biopsies in Dogs and Cats

Background: Prior studies failed to detect significant association between hypoalbuminemia and small intestinal lesions. Hypothesis: Use of pictorial templates will enhance consistency of interpathologist interpretation and identification of intestinal lesions associated with hypoalbuminemia. Animals: Tissues from 62 dogs and 25 cats examined as clinical cases at 7 referral veterinary practices in 4 countries. Methods: Retrospective, observational study. Histopathology slides from sequential cases undergoing endoscopic biopsy were examined by 4 pathologists by pictorial templates. Changes for 9 microscopic features were recorded as normal, mild, moderate or severe, and 2- and 4-point scales were tested for consistency of interpretation. Logistic regression models determined odds ratios (OR) of histologic lesions being associated with hypoalbuminemia while k statistics determined agreement between pathologists on histologic lesions. Results: There was poor agreement (k= -0.013 to 0.3) between pathologists, and institution of origin of slides had effect (k = 1.0 for 3 of 4 lesions on slides from Institution 5) on agreement between pathologists on selected histologic features. Using 2 point as opposed to 4-point grading scale increased agreement between pathologists (maximum k = 0.69 using 4-point scale versus maximum k = 1.0 using 2-point scale). Significant association (P = .019\u2013 .04; 95% OR = 3.14\u201310.84) between lacteal dilation and hypoalbuminemia was found by 3 pathologists. Conclusions and Clinical Importance: Substantial inconsistency between pathologists remains despite use of pictorial template because of differences in slide processing. Distinguishing between mild and moderate lesions might be important source of the disagreement among pathologists