Effect of intestinal location on growth and function of neomucosa

Abstract

Growing intestinal neomucosa in patched intestinal defects has been investigated as a means of permanently increasing the absorptive capacity in the short bowel syndrome. Several factors, including luminal contents, appear to affect the growth and function of the neomucosa. The purpose of this study was to compare function and rate of growth of neomucosa in patched defects of the jejunum and ileum. In both the jejunum and ileum of 11 New Zealand white male rabbits 2 × 5-cm patched intestinal defects were created using the serosal surface of adjacent colon. The animals were sacrificed at 4 weeks ( n = 6) and 8 weeks ( n = 5) after operation. Grossly there was more complete coverage of the defect by neomucosa in the ileum at both 4 and 8 weeks (99.1 ± 1.1% vs 92.6 ± 6.3% overall P < 0.005). Villous height of the ileal neomucosa was similar to normal mucosa at 8 weeks (209 ± 21 vs 244 ± 18 m) but was significantly less in the jejunum (209 ± 16 vs 273 ± 16 m, P < 0.005). Glucose uptake by neomucosa was greater in the ileum than the jejunum (3.34 ± .84 vs 2.39 ± .46 nmole/min/mg, P < 0.05) but was similar to normal mucosa at both sites. Disaccharidase activity (lactase, sucrase, and maltase) was similar in both jejunum and ileum but was significantly less in ileal neomucosa than in normal mucosa ( P < 0.005). Taurocholate uptake was greater in the ileum in both normal mucosa (0.76 ± 0.12 vs 0.44 ± 0.11 nmole/min/mg, P < 0.1) and neomucosa (0.68 ± 0.15 vs 0.41 ± 0.05, P < 0.1). Neomucosa grows faster in the ileum than the jejunum. Glucose and taurocholate uptake are greater in the ileal neomucosa, reflecting the longitudinal specialization of the gut. The ileum would be the most desirable site for growing neomucosa in the clinical setting.