Permeability of intestinal mucosa from urinary reservoirs in man and rat

Objective To evaluate the barrier properties of intestinal mucosa chronically exposed to urine and to evaluate possible differences between ileal and colonic segments used in the reconstruction of the urinary tract. Materials and methods Mucosal specimens from patients with continent reservoirs with an abdominal stoma, or orthotopic neobladders constructed from colonic segments, were obtained at revisional surgery. Control segments were obtained during right‐sided hemicolectomy. In addition, ileal and colonic segments from enterocystoplasties in rats were assessed. The mucosa‐to‐serosa passage of marker molecules, i.e. 14 C‐mannitol, 3 H‐glucose, fluorescein isothiocyanate‐dextran 4400 and ovalbumin, was measured using modified Ussing diffusion chambers. Results In man, there were no permeability differences between segments exposed to urine and control segments for any of the marker molecules. In rats, there was less passage of markers in ileal and colonic transplanted segments than in intestinal segments from sham‐operated animals. Conclusions Intestinal mucosa that has been in chronic contact with urine maintains its barrier function; in the rat model the permeability was even decreased. In addition, there were no detectable differences between ileal and colonic segments in this model.