Extrinsic Denervation Alters Postprandial Absorption of Glucose and Glutamine in the Ileum: Implications For Small Bowel Transplantation
Abstracts
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In the postprandial period, augmentation of absorption of water, electrolytes and taurocholate occurs in the ileum (J Surg Res, 1995). The role of the extrinsic nervous system in this postprandial augmentation has not been well studied and may be important in small bowel transplantation. AIM: To investigate extrinsic neural mechanisms mediating postprandial absorptive patterns. HYPOTHESIS: Ileal postprandial absorption is blunted in transplanted (extrinsically denervated) bowel. METHODS: 6 dogs were used to measure absorption in an 80-cm ileal segment via a triple-lumen perfusion technique. Using an isosmolar, ileal-like electrolyte solution (in mEq/L, Na+ 140, K+ 5, Cl- 110, HCO3- 35) containing one of four nutrients (glucose 2.5 mM, glutamine 2.5 mM, oleic acid 5 mM, taurocholic acid 5 mM), net absorptive fluxes of each were measured in the fasted state and after a 400-kcal, mixed meal before, and 2 and 12 wk after our validated model of complete extrinsic denervation of the jejunoileum. RESULTS: All dogs developed diarrhea after extrinsic denervation that resolved in 4-6 wk. At baseline, there were no differences in absorption of each nutrient postprandially compared to the fasted state. Although fasting absorption of glucose was unchanged 2 wk after denervation, absorption of glucose at both 1 and 2 hr postprandially decreased (table). Similarly, while fasting absorption of glutamine was unaltered 2 wk after denervation, glutamine absorption decreased 2 hr after a meal compared to fasting absorption. No differences were noted in postprandial absorption of oleic acid or taurocholate. SUMMARY: Extrinsic denervation decreases postprandial net absorptive fluxes of glucose and glutamine in the ileum. CONCLUSIONS: Decreases in absorption postprandially after extrinsic denervation (which is necessitated by SBT) may play an important role in post-transplant enteric absorptive dysfunction. |
