Histologic studies of the bypassed stomach after Roux-en-Y gastric bypass in a porcine model

Background: Laparoscopic Roux-en-Y gastric bypass (LRYGBP) is highly effective for morbid obesity. However, the long-term effects in the bypassed segments are unknown. The aim of this study is to evaluate gastrin and histologic changes in bypassed segments after LRYGBP. Methods: 10 50-kg pigs were subjected to LRYGBP. Preoperative weight and serum gastrin were compared with similar measures at 6 months postoperatively, when the pigs were euthanized. At necropsy, full-thickness gastric, duodenal, and jejunal biopsies were performed. Normal biopsies were obtained from a control group of 10 pigs. Results: 1 pig died at 3 months postoperatively because of an intestinal intussusception. In the remaining 9 pigs, weight increased after surgery from 52±2.2 kg to 55±1.9 kg. Serum gastrin was unchanged after surgery (mean 68.2 vs 68.3 pg/mL at 3 months and 61.7 pg/mL at 6 months). Histology showed no abnormalities from sections in all control pigs, and in 7 of the LRYGBP pigs as well. 1 LRYGBP pig was found to have hyperplastic duodenal glands, jejunal mucosa with mild chronic inflammation, and gastric mucosa with focal erosive gastritis. 1 LRYGBP pig had jejunal sections showing Peyer's patches. Conclusion: LRYGBP is not associated with gastrin changes and major histologic changes in the bypassed segments, at 6 months postoperatively in the porcine model.