Effect of elective surgery on protein synthesis in intestinal mucosa

Background/aim: Intestinal mucosa plays an important role in maintenance of the intestinal barrier function and in prevention of postoperative anastom otic leakage. An adequate acceleration of intestinal proliferation and coll agen synthesis is essential for an efficient healing of injured bowel. Thes e processes require a sufficient rise in protein synthesis. Thus far, post- surgical changes in intestinal protein synthesis have not been studied. Methods: Ileum and colon mucosa protein synthesis were examined in control subjects and in patients after curative abdominal surgery. Mucosa biopsies could be obtained via ileostomies (control n = 6, post-surgery n = 6) and c olostomies (control n = 6, post-surgery n=6). Protein synthesis was measure d by the incorporation of 1-C-13-leucine into mucosa protein. Enrichment of free intracellular amino acids was taken as an indicator of the true precu rsor pool enrichment. During continuous isotope infusion, tissue samples we re obtained after three, six and ten hours to generate baseline data and da ta after a prolonged fasting period. Results: During isotope infusion, the enrichment in the free intracellular amino acid pool remained constant indicating a steady state in the precurso r pool enrichment. Compared to controls, postoperative patients demonstrate d a rise in ileum protein synthetic rate (1.11 +/- 0.14 %/h, p < 0.01 vs co ntrols 0.62 +/- 0.06), whereas only minor changes were observed in the colo n (1.01 +/- 0.17 %/h, not significant vs 0.74 +/- 0.09). Prolonged fasting reduced protein synthesis postoperatively in the ileum (0.39 +/- 0.13 %/h, p < 0.01 vs baseline 1.11 +/- 0.14), but not in the colon (1.03 +/- 0.05 %/ h, not significant vs baseline 1.01 +/- 0.17). Conclusion: These data demonstrate that the proliferative response is only adequate in small bowel, in which it is, however, also sensitive to fasting . These data may explain the well-known clinical finding that the risk of a nastomotic leakage is markedly lower in small than in large bowel.