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Abstract

Parallel changes in spontaneously occurring inflammation in colonic Thiry-Vella loops and the in-line colon of cotton-top tamarins were studied in a colitis-inducing environment at 8 and 15 months following surgical preparation of the loops. Gross disease severity and numbers of inflammatory/immune cells per unit area of lamina propria in histological sections from endoscopic biopsies were analyzed. Cell counts and severity of colitis declined over time in the Thiry-Villa loops while the disease followed its characteristic course in the remaining large bowel and in the colons of controls. Perfusion of the loops with the animals' feces increased the density of the cellular infiltrate in the lamina propria in parallel with increased severity of inflammation. Electron micrographs of the colonic mucosa showed invasion by microorganisms. The predominant microorganism had characteristics of Helicobacter sp. The results implicate the fecal stream as a factor in the persistence of colitis in the tamarin model. Nevertheless, fecal factors appear not to be the primary trigger, as evidenced by findings that the disease is not expressed in wild-living tamarins and that it enters remission when affected animals are transferred to natural conditions from a colitis-inducing environment. Both an adverse environment and the fecal contents appear to be required for expression of the disease.

Animal models of colorectal cancer

“…Efforts to identify a heritable or familial cause for this syndrome have failed (55) and there are no reports detailing the molecular nature of these adenocarcinomas. The cause of the syndrome is unknown, but there is evidence that environmental stress (56) and luminal bacteria (57) may play a role in its pathogenesis. The similarities to the human disease and spontaneous nature of these adenocarcinomas are features beneficial in modeling therapeutic and preventative interventions.…”

The Effects of Physical and Psychological Stress on the Gastrointestinal Tract: Lessons from Animal Models

“…In the early 80´s the spontaneous development of colonic inflammation in this small primate from Central America was initially described [47,48]; later on it was noted that the frequency of colitis was, to a large extent, significantly higher in animals under captivity, compared to animals living in their wild environment [49][50][51]. This fact underlined the essential role of an environmental factor -reasonably psychological stress due to captivity -in the pathogenesis of the disease in these animals, serving as an excellent animal model of stress-related disorder.…”

“…Altered barrier function might be also be involved in visceral hypersensitivity observed in animal models of stress, chemical-induced colitis and parasite infection, and that characterize postinfectious human IBS [98]. Increased intestinal permeability has been uniformly observed after acute and chronic stress exposure in rodents [25,[99][100][101][102] by means of different experimental approaches assessing the intestinal permeability both in vivo -with probe molecules such as small carbohydrates or 51 Cr-EDTA -and in vitro, mounting intestinal segments on Ussing chambers. Macromolecular and bacterial passage across the intestinal epithelium of animals exposed to a variety of stressors seems to occur mainly via paracellular pathway [25,32,100] in a sequence of events that are mainly dependent on tight junction dysfunction [25,32,103] (see below); nevertheless, acute and, to a greater extent, chronic stress also lead to an increased transcellular transport of antigens and bacteria by follicleassociated epithelium of rat small bowel [104].…”

Review on the Influence of Stress on Immune Mediators, Neuropeptides and Hormones with Relevance for Inflammatory Bowel Disease

“…Further, cotton-top tamarins develop colitis in captivity. Remission of the disease will be entered by transferring affected tamarins to natural living conditions [70]. …”