Functional and morphologic changes of the ileal mucose after ileoanal pouch procedure

Background: Restorative proctocolectomy is used widely for treatment of ulc erative colitis and familial polyposis coli, Limited information is availab le regarding the morphologic and functional adaptation of the mucosa in a f unctioning ileoanal pouch. Study Design: Ileal pouch specimens from patients who underwent pouch recon struction (mean 7.5 years postcolectomy, n=12) were compared with normal il eum (n=15) and normal colon (n=5). Amino-oligopeptidase (AOP) and maltase a ctivity were measured as parameters of normal ileal function. Histologic sa mples were examined for the presence of neutrophils and plasma cells, the v illus to crypt height ratio, and the degree of crypt hyperplasia, villus bl unting, and goblet cell mass. Data were analyzed by analysis of variance. Results: The AOP activity in the normal ileum was 73 +/- 32 units of enzyma tic activity per gram of mucosal protein; the AOP activities of the pouch a nd colon were 21 +/- 22 and 16 +/- 10, respectively. The maltase activity o f the normal ileum measured 254 +/- 116 units of enzymatic activity per gra m of mucosal protein, and the maltase activities of the pouch and colon wer e 57 +/- 71 units and 29 +/- 25 units, respectively The ileal pouch mucosa demonstrated little acute inflammation and varying degrees of chronic infla mmation. Morphologically, the ileal pouch mucosa demonstrated a range of ad aptations, including villus blunting and crypt hyperplasia, Several specime ns contained immature epithelial cells. Conclusions: The AOP and maltase activities in mucosa from ileoanal pouches and colon were significantly lower than those in normal ileal mucosa. Ileo anal pouch mucosa from humans undergoes adaptive changes to resemble coloni c mucosa both morphologically and functionally. (J Am Coll Surg 2000;190:31 0-314. (C) 2000 by the American College of Surgeons).