Small bowel transplantation (SBT)is complicated by severe diarrhea possibly 2 to abnormal motility. Ileal motility after SBT is poorly investigated. AIM: To determine roles of extrinsic innervation and continuity of the enteric nervous system in ileal motility. HYPOTHESIS: Typical ileal motor patterns persist after SBT but lack temporal coordination with duodenum.
METHODS: 4 dogs with manometry catheters in duodenum, jejunum and ileum to measure motor activity were studied during fasting (n=4/dog) and after feeding small (50 g) and large (200 g) liver meals (n=2/meal/dog). Dogs then underwent a validated model of in situ neural isolation of jejunoileum to disrupt extrinsic and intrinsic neural input to the ileum. All nerves, and all other connective tissue to jejunoileum were transected (except for superior mesenteric artery and vein), and proximal jejunum and distal ileum were transected and reanastomosed. Fasting and postprandial studies were repeated 2 wk later.
RESULTS: After jejunoileal denervation, duodenal and ileal cyclic motility (migrating motor complex-MMC) persisted, but unlike controls, duodenum and ileum were temporally discoordinated and cycled independently. Parameters of ileal phase III motility (duration, veocity, no. of contractions, motility index) did not differ before and after denervation (table). Durations of cycles (mean±SEM) of ileal MMC were similar before and after denervation (113±5 vs 143±17 min; p>0.05). Only 74±6% of jejunal MMCs migrated to distal ileum versus 100% in controls. Postprandially, both small and large meals inhibited the ileal MMC in controls; after denervation, only large meals inhibited ileal motility.
SUMMARY: Disruption of extrinsic and intrinsic neural continuity did not alter the fasting ileal MMC but did interrupt regional coordination with duodenal motility. Postprandial inhibition of ileal MMC was altered after small meals.
CONCLUSIONS: Regional temporal discoordination of small bowel motor activity after SBT may have significant effects on enteric function. (Support NIH R01 39337-MGS)
Group Duration Velocity # contractions Motility index
Control 6±1 min 1±1 cm/min 85±5 12±1
Denervated 7±1 min 2±1 cm/min 86±4 13±1
x±SEM; n=4 dogs. No statistical differences noted.