Segmental small bowel transplantation (SBT) offers theoretic advantages over total jejunoileal transplantation, but regional ability of the transplanted segment to adapt has not been well investigated. AIM: To investigate extrinsic neural mechanisms mediating jejunal adaptation to total ileal resection.
HYPOTHESIS: Adaptive response is blunted in denervated bowel.
METHODS: 14 dogs were implanted with cannulae in proximal jejunum to measure absorption in an 80-cm segment via a triple lumen perfusion technique. After 2 wk, separate studies measuring baseline absorption of water, electrolytes, and 4 3H-labelled nutrients (glucose, glutamine, oleic acid and taurocholic acid) were performed (2 studies per dog with each solution). Control dogs (CON, n=6) then had the distal 50% of small bowel resected, preserving ileocecal valve. Experimental dogs (EXP, n=8), underwent distal 50% enterectomy and extrinsic denervation of jejunoileum; this validated model of (auto)transplantation avoids immune rejection and ischemia/reperfusion. Absorptive studies were repeated in both groups 2 and 12 wk later.
RESULTS: All dogs developed diarrhea which resolved in all but 1 CON dog but persisted in all 8 EXP dogs. Maximal weight loss was greater in EXP (3.7±0.2 vs 2.1±0.2 kg; p<0.05). Glucose and oleate absorption was decreased at 2 wk after ileal resection in both CON and EXP; glutamine absorption was decreased at 2 wk in EXP only. All values returned to baseline at 12 wk (Table). Net fluxes of tauro-cholate and water were unchanged in both groups. Summary: Distal 50% enterectomy induces a short bowel syndrome worsened by extrinsic denervation. Despite more weight loss and persistent diarrhea, there were no differences in absorptive fluxes 12 wk after denervation.
CONCLUSION: Extrinsic denervation as necessitated by SBT does not blunt the jejunal adaptive response to total ileal resection. (Support NIH R01 DK39337-MGS)
Glucose Glutamine Oleic acid
CON EXP CON EXP CON EXP
Baseline 4.2±0.5 4.0±0.4 4.0±0.4 4.1±0.2 9.7±1.0 9.2±0.5
2 wk 2.7±0.6* 2.5±0.8* 3.5±0.7 2.6±0.4* 6.3±0.5* 5.8±0.8*
12 2k 3.7±0.3 4.0±1.1 4.4±1.0 3.6±0.6 8.0±1.6 7.5±1.5
Absorptive fluxes (mM cm-1 10-2) are x±SEM, *p<0.05 vs baseline.