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  • Author or Editor: Michael J. Wannemuehler x
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Abstract

Objective

To validate use of canine colonic biopsy specimens obtained via endoscopy as a source of mucosal lymphocytes (ML) for flow cytometric analysis.

Sample Population

Mucosal biopsy specimens from 10 adult dogs.

Procedure

Mucosal lymphocyte subsets obtained from excised colon were compared with ML subsets obtained from biopsy specimens obtained by use of an endoscopic forceps (6 dogs). Endoscopic colonic biopsy specimens from 4 other dogs were used to define whether obtained ML were predominantly of intraepithelial or lamina propria origin. Mucosal lymphocytes were isolated and labeled, using commercially available monoclonal antibodies directed against canine cell surface antigens. Lymphocyte subsets (cytotoxic or helper T cells; B cells) were determined by use of flow cytometric analysis.

Results

A large number of viable ML was obtained after dissociation of the colonic epithelium from excised colon (45.5 ± 21.5 × 106) and endoscopic (7.2 ± 3.4 × 106) biopsy specimens. Lymphocyte subsets obtained with both methods were identical for each dog and consisted predominantly of intraepithelial lymphocytes, with some lymphocytes from the lamina propria. Collagenase digestion of excised colon also yielded a large number of viable lymphocytes from the lamina propria (56.7 ± 20.4 × 106), but collagenase digestion of endoscopic biopsy specimens was less rewarding.

Conclusion and Clinical Relevance

A representative sample of viable intraepithelial ML is obtainable from endoscopic biopsy specimens. Flow cytometric analysis, a minimally invasive technique, can be used to study ML of client-owned animals. (Am J Vet Res 1999;60:346-353).

Free access
in American Journal of Veterinary Research

Abstract

Objective—To characterize mucosal gene expression in dogs with chronic enteropathy (CE).

Animals—18 dogs with CE and 6 healthy control dogs.

Procedures—Small intestinal mucosal biopsy specimens were endoscopically obtained from dogs. Disease severity in dogs with CE was determined via inflammatory bowel index scores and histologic grading of biopsy specimens. Total RNA was extracted from biopsy specimens and microchip array analysis (approx 43,000 probe sets) and quantitative reverse transcriptase PCR assays were performed.

Results—1,875 genes were differentially expressed between dogs with CE and healthy control dogs; 1,582 (85%) genes were downregulated in dogs with CE, including neurotensin, fatty acid–binding protein 6, fatty acid synthase, aldehyde dehydrogenase 1 family member B1, metallothionein, and claudin 8, whereas few genes were upregulated in dogs with CE, including genes encoding products involved in extracellular matrix degradation (matrix metallopeptidases 1, 3, and 13), inflammation (tumor necrosis factor, interleukin-8, peroxisome proliferator–activated receptor γ, and S100 calcium-binding protein G), iron transport (solute carrier family 40 member 1), and immunity (CD96 and carcinoembryonic antigen–related cell adhesion molecule [CEACAM] 18). Dogs with CE and protein-losing enteropathy had the greatest number of differentially expressed genes. Results of quantitative reverse transcriptase PCR assay for select genes were similar to those for microchip array analysis.

Conclusions and Clinical Relevance—Expression of genes encoding products regulating mucosal inflammation was altered in dogs with CE and varied with disease severity.

Impact for Human Medicine—Molecular pathogenesis of CE in dogs may be similar to that in humans with inflammatory bowel disease.

Full access
in American Journal of Veterinary Research