Intestinal permeability in humans is increased after radiation therapy.
Methods: Segments from sigmoid colon and rectum obtained from irradiated and nonirradiated patients were stripped from the serosa-muscle layer and mounted in Ussing diffusion chambers. The mucosa-to-serosa passage of the marker molecules 14C-mannitol, fluorescein isothiocyanate-dextran 4,400, and ovalbumin was followed for 120 minutes.
Results: The permeability to the markers was size-dependent and increased linearly across time in all specimens. The passage of all markers was increased in irradiated rectum compared with nonirradiated sigmoid colon, whereas in specimens from nonirradiated patients there were no differences between rectum and sigmoid colon. Histologic signs of crypt and mucosal atrophy were found in the irradiated rectal specimens.
Conclusions: Early gastrointestinal complications after radiation therapy may be the result of mucosal atrophy in addition to mucosal damage, with a loss of barrier integrity.
Dis Colon Rectum. 2000 Nov;43(11):1582-1587; discussion 1587-8. doi: 10.1007/BF02236743. PMID: 11089597.