Abstracts
1999 Digestive Disease Week

# 2165 EFFECT OF THE DISTAL REMNANT ON ILEAL ADAPTATION.
D C Ferguson, Jon S Thomspon, Univ of Nebraska Med Ctr, Omaha, NE

The ileum has a greater adaptive capacity than the jejunum after intestinal resection. Previous studies suggest that this is, in part, related to increased exposure to nutrients and intrinsic properties of the ileum. However, the intestinal remnant might contribute to this response as well. The aim of this study was to compare the effect of the distal intestinal remnant on ileal adaptation when the ileum is proximal in the intestinal tract. METHODS 21 Lewis rats were included in the study. One group (n=7) served as unoperated controls. The second group (n=7) had transposition of the jejunum and ileum. The third group (n=7) had 50% proximal resection with syngeneic transplantation of ileum. Nutritional status and structural adaptation were studied at 14 days. RESULTS Animals in both transposition and transplant groups initially lost weight but returned above preoperative weight at 14 days. Serum albumin levels (2.5 ± 0.1 and 2.6 ± 0.1 gm/dL) were similar at 14 days. Average daily food intake (20.3 ± 0.8 and 19.1 ± 0.9 gm/day) and stool weight (3.9±0.1 and 4.1±0.2 gm/day) were similar in these two groups. Intestinal weight and diameter were similar in proximal ileal segments in the two study groups and were significantly increased compared to unoperated ileum (.26 ± .04 and .31 ± .02 vs .10 ± 0.0 gm/cm and 8.4 ± 0.5 and 9.1 ± 0.8 vs 4.9 ± 0.3 mm, P <.05). Intestinal weight and diameter of the distal end of the ileal segment were greater than unoperated controls but were greatest in the ileal transplant group. (.15 ± 0.1 and .24 ± .03 vs .07 ± .01 gm/cm and 5.6 ± 1.1 and 8.7 ± 0.6 vs 4.3 ± 0.2 mm, P <.05). Villus height was similar in both proximal and distal ileal segments in the two study groups and were significantly increased compared to unoperated ileum (642 ± 75 and 720 ± 15 vs 411 ± 24 proximal and 443 ± 49 and 500 ± 46 vs 343 ± 22 mm distal, P <.05. Crypt depth was also similar in the two study groups and greater than unoperated controls (223 ± 34 and 244 ± 33 vs 173 ±20 proximal and 192 ±28 and 209 ± 18 vs 144 ± 26 um distal, P <.05). Crypt cell production rate was similar in all segments. CONCLUSIONS: Proximal placement of the ileum results in structural adaptation. This occurs to a similar extent whether the distal remnant is jejunum or ileum. Thus, nutrient load and intrinsic properties appear to be the important factors in the adaptive capability of the ileum when the ileum is proximal in the intestinal tract.

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