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The effect of endotoxin on canine colonic motility and transit.
ST Spates, JJ Cullen, KS Ephgrave, MM Hinkhouse.
Department of Surgery, University of Iowa College of Medicine and VAMC, Iowa City, IA.

Diarrhea is a common problem in patients who have episodes of sepsis and are being fed enterally. Endotoxemia results in gastrointestinal motor dysfunction characterized by slowed gastric emptying (J. Surg. Res. 58:90, 1995) and rapid intestinal transit (J. Surg. Res. 60:307, 1996), however, the effect of endotoxin on colonic motility is unknown. AIMS: To determine the effects of a single, sublethal dose of endotoxin on colonic motility and transit. METHODS: Five dogs underwent construction of 50 cm colonic Thiry-Vella fistulas (TVF). Five manometry catheters were sewn into the colonic lumen at 8 cm intervals along the TVF. Following recovery, the TVF was perfused with an isotonic solution at 2.9 ml/min and fasting and postprandial colonic motility were determined. Liquid transit was assessed by bolus of a non-absorbable marker instilled into the proximal end of the TVF. Recordings of gastrointestinal contractile activity were made digitally to determine contractile frequencies and motility indexes. Following completion of the baseline studies, each dog was given a single dose of E. coli lipopolysaccharide 200 µg/kg IV and studies were repeated daily for the next three days. RESULTS: Endotoxin doubled the postprandial colonic contractile frequency on postendotoxin day 1 and also increased motility indexes on that same day (Table). Postprandial liquid transit was rapid on postendotoxin day 1. The postprandial frequency of contractions and motility indexes returned to baseline levels on postendotoxin day 2 and postendotoxin day 3. CONCLUSIONS: Endotoxin temporarily speeds liquid transit and increases both the frequency and strength of postprandial colonic contractions. These effects may contribute to the diarrhea that occurs with enteral feeding during episodes of sepsis. Support: VA Merit Review.

Postendotoxin

Postprandial
colonic motility	Baseline	Day 1	Day 2	Day 3
contractions/30 min	22 ± 6	50 ± 24	14 ± 2	17 ± 4
MI/30 min	379 ± 113	10808 ± 1224*	257 ± 57	337 ± 84
Transit (min)	14.9 ± 2.7	9.1 ± 1.7*	11.6 ± 2.0	18.1 ± 4.0
#Means ± SEM, *P < 0.05 vs baseline. MI = motility index.