Canine model of human fistulizing Crohn's disease

Perianal lesions represent one of the most important complications for patients suffering from Crohn's disease (CD). Particularly, the presence of anal fistulizing disease represents a predictor of poor long-term outcome in CD patients. The pathophysiology of perianal fistulizing CD is not well understood. There is not a good animal model to study the relevance of the microbiota in perianal fistulizing CD. Here we aim to characterize the microbiota of dogs spontaneously suffering from canine anal furunculosis (CAF), a disease with a clinical similarity to that of perianal fistulizing CD. CAF is characterized by inflammation and ulceration of the perianal tissues with development of cutaneous sinuses or rectocutaneous fistulae. Twenty German Shepherd dogs were recruited for this study. Twelve dogs exhibited active CAF while eight dogs were healthy. Fecal samples were collected daily for a week and were sequenced for microbiome analysis. We found that dogs suffering from CAF do exhibit a distinct microbiota from those of healthy dogs. As observed in human patients with CD, the microbiota of CAF-dogs is bimodal, with dogs exhibiting microbiomes very distant from the healthy controls, and other dogs with similarities- yet still unique -from the healthy controls.