DIETARY MODULATION OF METHOTREXATE-INDUCED ENTERITIS IN CATS

Objective-To determine effects of purified and dry expanded (complex) diets on intestinal structure and function in healthy cats and in a fe line model of methotrexate-induced enteritis. Animals-19 adult specifi c-pathogen-free cats. Procedure-Cats were randomized in groups to rece ive a purified diet intragastrically or a complex diet orally to meet their daily metabolizable energy requirements. After 21 days, cats rec eived either methotrexate (MTX; 10 mg/kg of body weight, IV, n = 12) o r saline solution IV (n = 7), and were anesthetized 72 hours later. Ce liotomy was performed for aseptic removal of mesenteric lymph nodes, f ull-thickness biopsy of the gastrointestinal tract, and collection of aortic and portal venous blood samples for determination of arterioven ous amino acid concentrations across the intestine. Results-MTX was as sociated with severe enterotoxicosis in cats receiving the purified di et, as manifested by diarrhea (4 of 6 cats) and vomiting (2 of 6 cats) . One cat receiving the complex diet developed mild diarrhea, and none of these cats vomited. The purified diet was associated with marked v illus blunting in the proximal and distal portions of the duodenum and increased bacterial translocation (3 of 6 cats), whereas none of the cats in the complex diet group developed bacterial translocation after MTX administration. For the cats given saline solution, bacterial tra nslocation occurred in 1 of 4 cats receiving the complex diet versus 2 of 3 cats receiving the purified diet. Conclusions-Feeding of a compl ex diet containing intact protein as the nitrogen source abrogated the proximal small intestinal atrophy and bacterial translocation associa ted with feeding an amino acid-based purified diet. Clinical Relevance -Use of purified diets containing free amino acids as the only nitroge n source cannot be endorsed in human and animal cancer patients receiv ing systemic chemotherapy.