Characterization of intestinal morphologic, biochemical, and ultrastructural features in gluten-sensitive Irish...

To characterize histologic, biochemical, and ultrastructural changes in the intestine of Irish Setters susceptible to gluten-sensitive enteropathy (GSE) during controlled oral challenge exposure with gluten after weaning.

Six gluten-sensitive and 12 healthy Irish Setters and 3 healthy Greyhounds.

Jejunal biopsy specimens were taken at 4 and 12 months of age from the 6 gluten-sensitive Irish Setters, which had been reared on a gluten-free diet to which a controlled dose of gluten (0.5 g/kg of body weight/d) was added. Control specimens were obtained at 4 (n = 5) and 12 (7) months of age from the healthy Irish Setters, which had been fed a conventional gluten-containing diet, and at 4 months of age from the healthy Greyhounds fed the controlled dose of gluten. The specimens were subjected to histologic and ultrastructural examinations and assay of brush border enzymes.

Gluten-sensitive Irish Setters developed abnormalities characteristic of GSE at 4 months. Abnormalities were comparable to changes not seen previously until 12 months in dogs with GSE fed a conventional gluten-containing diet. In addition, microvilli were stunted and irregular, and a few were vesiculated and reduced in number; the glycocalyx was reduced or absent. By 12 months of age, there was improvement in morphologic and biochemical parameters, indicating partial recovery despite continued exposure to gluten.

Relative early onset of intestinal damage, compared with that previously reported, and subsequent partial recovery suggestive of oral tolerance to gluten may be attributable to oral administration of gluten as a purified extract rather than in dietary cereal, but alternative explanations include differences in environment or genetic susceptibility to gluten.