Intestinal permeability and bacterial translocation are uncoupled after small bowel resection

Background/Purpose: Gut barrier failure and bacterial translocation have been proposed to cause infection and sepsis in patients with the short bowel syndrome. This study tested the hypothesis that permeability is increased in the adapting remnant ileum after massive small bowel resection (SBR). Methods: Male ICR mice underwent a 50% proximal SBR or sham operation. At 3,7, and 14 days, the ileum was mounted in an Üssing chamber. Mucosal-to-serosal flux of low (dextran) and high (horseradish peroxidase; HRP) molecular weight markers was determined. Additionally, bacterial translocation was measured by culturing blood, mesenteric lymph nodes, liver, and spleen at 3 and 14 days after SBR or sham operation. Results: Permeability to dextran was reduced immediately after SBR but was no different at later time-points. HRP permeability was no different at any time-point. Translocation of Gram-negative bacteria to the mesenteric lymph nodes and liver was more frequent in the SBR animals 3 and 14 days postoperatively. Conclusions: Intestinal permeability to macromolecules is not increased after massive SBR, but the rate of translocation to the mesenteric lymph nodes and liver is elevated. This suggests that the mechanism for bacterial translocation after SBR does not involve alterations in gut permeability.