Biochemical changes in the jejunal mucosa of dogs with a naturally occurring enteropathy associated with bacterial overgrowth.

Abstract

SUMMARY The subcellular biochemical features of a naturally occurring enteropathy in the dog associated with bacterial overgrowth have been examined. Affected animals comprised a group of 10 German Shepherd dogs with raised serum folate and reduced vitamin B12 concentrations, mild steatorrhoea, reduced xylose absorption, and normal exocrine pancreatic function. Culture of duodenal juice showed bacterial overgrowth with mixed flora, most frequently including enterococci and Escherichia coli. Examination of peroral jejunal biopsies revealed predominantly minimal histological but distinct biochemical abnormalities in the mucosa. The specific activity of alkaline phosphatase was decreased, isopycnic density gradient centrifugation showing a marked loss particularly of the brush border component of enzyme activity. In contrast, y-glutamyl transferase activity was enhanced in brush border fragments of slightly increased modal density, but there were no changes in the activities of the carbohydrases, zinc-resistant a-glucosidase, maltase, sucrase, and lactase or of the peptidase, leucyl-2-naphthylamidase. Activities of lysosomal enzymes were increased and there was evidence for enhanced lysosomal fragility and mitochondrial disruption. The activities and density gradient distributions of marker enzymes for basal-lateral membranes, endoplasmic reticulum and peroxisomes were essentially unaltered. These findings show that bacterial colonisation of the proximal small intestine may be associated with specific alterations in microvillus membrane proteins and provide biochemical evidence for intracellular damage to the enterocytes.

Chronic small intestinal disease in the dog

“…A detailed comparison with the changes described in bacterial overgrowth due to the 'blind-loop syndrome' (BLS) in man and in experimental animals has been discussed elsewhere (Batt, Carter & Peters, 1984). In agreement with the findings in this group of German Shepherd dogs, histological changes in the 'blind-loop syndrome' are frequently minimal; however, the biochemical abnormalities appear to vary, depending not only on the numbers but also the types of bacteria isolated.…”

“…This enteropathy has been described in a series of ten German Shepherd dogs, one aged 9 years and the remainder aged between 5 months and 2 years (Batt, Carter & Peters, 1984). All animals had a history of intermittent diarrhoea, with or without loss of weight, and had exhibited clinical signs for at least 3 months, two cases since they were 1-year-old and the other dogs since they were approximately 2-months-old.…”

Pediatric small intestine bacterial overgrowth in low-income countries

“…In SIBO, histology is often normal but villous atrophy and distortion, mitochondrial swelling, and vacuolization of microvillus membranes have been described[44, 46, 61] (Figure 2). SIBO has been shown to result in increased concentrations of interleukin 6 (IL-6), but not interferon γ (IFN-γ) and tumor necrosis factor α (TNF-α) in the small intestine, especially when SIBO involves colonic-type flora[62].…”

Immune Cell Populations within the Duodenal Mucosa of Dogs with Enteropathies

“…The pathogenesis of SIBO is unclear, although initial reports suggested that increased bacterial numbers within the duodenal lumen may play an important role. [4][5][6][7] Against this hypothesis is the observation that similar bacterial numbers can occur in the duodenum of some healthy dogs, [8][9][10] and the fact that total bacterial numbers do not decline after successful antibiotic treatment. 11 Although the etiopathogenesis of SIBO is not known, a recent study has suggested that the mucosal immune system may be important.…”