The potential role of gluten in equine inflammatory small bowel disease

Abstract

Background Equine inflammatory small bowel disease (ISBD) is an idiopathic pathologic condition of the small intestine characterised by substantial reduction of the available absorptive surface area. Signs include a dull hair coat, weight loss, recurrent colic and at times soft faeces, depression and oedema. ISBD is a rare disease that in recent years seems to be increasing in frequency. Different aetiologies are suggested in today’s literature, such as abnormal host inflammatory reaction to intestinal bacteria, parasitic antigens and dietary components.

Aims To clarify the role of gluten in equine ISBD, aiming at improved diagnostic and treatment modalities. To find out if there is an analogy between coeliac disease in humans and ISBD in horses.

Methods Comparing different tests: the blood samples of 3 different groups (ISBD patients (n=12), gluten-rich controls (n=22) and gluten-free controls (n=25)) were ELISA tested for IgA antibodies against E. coli, human recombinant tissue-transglutaminase (rh-tTGA), guinea pig tissue-transglutaminase (gp-tTGA), antigliadin, deamidated-gliadin-peptides (anti-DGP) and, by using IFT, antibodies against endomysium (EmA). Differences between groups were statistically compared by means of the Mann-Whitney U-test. ρ values < 0,05 were considered significant. One patient was followed after adjustment to a gluten-free diet period for 6 months.

Results Both ISBD patients and the gluten-rich controls had significant (ρ < 0.0004) higher rh-tTGA than the gluten-free controls. Concentrations of anti-DGP antibodies were significantly (ρ = 0.024) higher in ISBD patients then in the gluten rich controls. The ELISA’s for gp-tTGA, antigliadin antibodies and the IFT for EmA’s were inconclusive as no clear relation was found between these and the use of gluten or ISBD. The patient, followed after a gluten-free diet period of 6 months showed reduced concentrations of all measured serological coeliac disease parameters.

Conclusion This is the first study to investigate the potential role of gluten in the aetiology of equine inflammatory small bowel disease. On the basis of these data it is not possible to draw clear conclusions on the role of gluten in equine inflammatory small bowel disease yet. But, the finding that rh-tTGA and DGP antibody concentrations are raised in horses fed a gluten-rich diet suggest an immune-stimulatory effect of gluten that could play a role in the aetiology of ISBD. The case, showing both clinically as well as serological improvement after a gluten-free diet supports this possibility. However, further research is needed to clarify the specifics.