DOES THE COLON ADOPT SMALL-BOWEL FEATURES IN A SMALL-BOWEL ENVIRONMENT

Background: Isoperistaltic colon interposition is one of several surgi cal options available in the treatment of short bowel syndrome. It fun ctions primarily by slowing the rapid intestinal transit that follows small bowel resection (SBR). Previous studies have interposed distal c olonic segments and although there is evidence of adaptation by the in terposed colon it is not known whether these segments develop histolog ic or functional small bowel characteristics. Methods: In this study e vidence was sought of metaplasia in the interposed segments after 80% SBR and, because proximal colon is a midgut derivative, the difference s between proximal and distal colonic segments were examined. Results: There was no qualitative histological evidence of metaplasia by the i nterposed segments. There was a significant increase in crypt depth, m ucosal thickness and maltase concentration of the interposed segments compared with the non-transposed colon of the controls. The maltase co ncentations were increased to the extent that they were not significan tly different from the concentration present in normal ileum. Conclusi ons: Although there was no gross evidence of small bowel intestinaliza tion by the interposed segments, there was evidence of adaptation whic h was not merely an extension of the adaptive process seen after SBR a lone. These changes resulted in the colon taking on some small bowel f eatures. There was no significant difference between proximal vs dista l interposed segments.