EFFECT OF REVERSED INTESTINAL SEGMENTS ON INTESTINAL STRUCTURE AND FUNCTION

Our aim was to evaluate the short-term effect of a reversed segment on structural and functional intestinal adaptation. Ten dogs underwent 7 5% distal resection and serosal electrode placement with (RS, n = 5) o r without (RO, n = 5) reversal of the terminal 10 cm of the remnant. N utritional status, absorption, motility, hormonal response, and remnan t adaptation were studied at 4, 8, and 12 weeks. Both groups lost weig ht (RO 89 +/- 3% and RS 76 +/- 8% of initial wt at 12 weeks). Hypoalbu minemia occurred in the RS animals (2.5 +/- .4 vs 2.9 +/- 4 g/dl, P < 0.05). Caloric intake was lower in RS animals during the first 2 weeks . Stool weight increased transiently (4 and 8 weeks) after RO (239 +/- 92 and 249 +/- 25 g/day vs 101 +/- 42 g/day, preop, P <.05) but not R S. Stool fat was elevated in both groups. Remnant length increased aft er RO (90 +/- 16 to 110 +/- 21 cm) but not after RS (89 +/- 8 vs 86 +/ - 9 cm). Morphometric changes were similar. Plasma PYY was increased a fter RO but not RS animals. Changes in tissue neuropeptides were simil ar. Intestinal transit time was increased 4 weeks after RS (19 +/- 9 v s 10 +/- 2 min) but was similar to RO thereafter. Myoelectrical activi ty in the reversed segment was persistently reversed and independent; only 11% of proximal Phase 3 complexes were propagated into the revers ed segment. The dominant motor pattern within this segment was orad-mi grating clusters and prolonged spike bursts. Rapidly migrating myoelec trical events, perhaps consequent on the obstructive effect of the rev ersed segment, were also noted throughout the small intestine in RS an imals. Reversed segments ameliorate diarrhea but impair nutritional st atus in the short term. The intestinal adaptive response is blunted. T he changes in RS relate to transiently decreased caloric intake, lack of hormonal responses, and altered myoelectrical activity. (C) 1995 Ac ademic Press, Inc.