Effects of ileal interposition on body weight and intestinal morphology in dogs.

Interposition of a segment of terminal ileum into the proximal jejunum has been shown to cause weight loss and hypertrophy of the pancreas and intestines of rats. To further evaluate the potential of ileal interposition as an anti-obesity procedure, weight loss, liver histology and intestinal morphology were studied in normal adult mongrel dogs. A 40 to 45-cm segment of distal ileum was transposed isoperistaltically on its vascular pedicle to the proximal jejunum (n = 14). Control dogs (n = 4) underwent transection and reanastomosis without interposition. Interposition resulted in a mean weight loss of 3.9 kg or 16 percent of body weight, over a 12-week period compared to a mean gain of 2.6 kg (11 percent of preop.) in the controls (P less than 0.025). Liver histology (n = 3) showed minimal fatty infiltration in one dog. Grossly, the transposed ileal segment did not show any consistent elongation or thickening of the bowel wall. Microscopically, there was complete jejunalization of the mucosa of the ileal segment which was indistinguishable histologically from the adjacent jejunal mucosa. Because of the variability of the weight response (-8.6 to +0.9 kg), further studies are required to evaluate the potential of this experimental procedure to achieve weight loss.