title: Markedly increased expression of interleukin-8 in the colorectal mucosa of inflammatory colorectal polyps in miniature dachshunds.
abstract: Inflammatory colorectal polyps (ICRPs) in miniature dachshunds were 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/or space-occupying large polyps in the colorectal area and are thought to be a novel form of inflammatory bowel disease (IBD). To explore key mediators in the pathogenesis of ICRPs, we analyzed several pro-inflammatory cytokine (IL-1β, IL-6, TNF-α, IL-8, IL-12p35, IL-12/23p40, and IL-23p19) mRNA expressions in colorectal polyps in ICRP dogs by quantitative PCR. Among these cytokines, IL-8 mRNA expression was markedly up-regulated in large polyps. To examine IL-8 protein expression, we analyzed IL-8 protein level and its location in colorectal mucosal specimens of ICRP dogs by ELISA and immunofluorescence microscopy. IL-8 protein was significantly increased in large polyps and serum in dogs with ICRPs compared to controls. By immunofluorescence microscopy, IL-8 was only localized in macrophages, but not in mucosal epithelial cells or neutrophils. IL-8-positive macrophages were significantly increased in large polyps compared to controls. These results suggest that IL-8 is produced mainly by macrophages and may induce neutrophil infiltration in the colorectal area of ICRP dogs.
authors.affiliation: Laboratory of Veterinary Internal Medicine, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Tamura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohta
authors.forename: Shidow
authors.initials: S
authors.lastname: Torisu
authors.forename: Masashi
authors.initials: M
authors.lastname: Yuki
authors.forename: Nozomu
authors.initials: N
authors.lastname: Yokoyama
authors.forename: Masahiro
authors.initials: M
authors.lastname: Murakami
authors.forename: Sue Yee
authors.initials: SY
authors.lastname: Lim
authors.forename: Tatsuyuki
authors.initials: T
authors.lastname: Osuga
authors.forename: Keitaro
authors.initials: K
authors.lastname: Morishita
authors.forename: Kensuke
authors.initials: K
authors.lastname: Nakamura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yamasaki
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Takiguchi
mesh_terms: D000818:Animals; D003111:Colonic Polyps / Q000276:immunology / Q000662:veterinary; D004283:Dog Diseases / Q000276:immunology*; D004285:Dogs; D005260:Female; D015212:Inflammatory Bowel Diseases / Q000276:immunology / Q000662:veterinary*; D016209:Interleukin-8 / Q000097:blood / Q000235:genetics*; D007413:Intestinal Mucosa / Q000276:immunology*; D007417:Intestinal Polyps / Q000276:immunology / Q000662:veterinary*; D008297:Male; D012333:RNA, Messenger / Q000032:analysis; D012002:Rectal Diseases / Q000276:immunology / Q000662:veterinary
chemical_list: D016209:Interleukin-8; D012333:RNA, Messenger
keywords: Colorectal mucosa; IL-8; Inflammatory colorectal polyps; Macrophage; Miniature dachshunds