Prospective evaluation of early morphological changes in pelvic ileal pouches.
OBJECTIVE
Little is known about the evolution of morphological changes in pelvic ileal-pouch mucosa. This study evaluates prospectively the sequence of early morphological, histochemical, and phenotypic features in pouch mucosal biopsy specimens.


METHODS
Twenty-two patients with pelvic ileal pouches constructed after total colectomy for chronic ulcerative colitis had biopsies performed at the time of ileostomy closure and after 6 weeks and 6 months of pouch function and were evaluated to assess the type and degree of inflammation, villus atrophy, Paneth's cell hyperplasia, mucin histochemical changes, the mucosal proliferative activity using the murine monoclonal antibody 1 (MIB-1), and the expression of the enzyme sucrase-isomaltase.


RESULTS
Early changes (6 weeks) were characterized by neutrophilic and eosinophilic inflammation, mild villus atrophy, Paneth's cell hyperplasia, a partial transition to colonic mucin phenotype, and an increased MIB-1 proliferation index. These features remained relatively stable after 6 months, except for a greater degree of mononuclear infiltration, a progressive increase in the degree of eosinophilic inflammation and a new higher steady state level of crypt epithelial kinetics. Expression of sucrase-isomaltase remained stable.


CONCLUSIONS
Pelvic ileal pouches develop inflammatory, phenotypic, and kinetic changes early in the course of function but have only a limited potential for colonic type metaplasia. The persistence of these changes is evidence in support of an adaptive response to a new luminal environment.
Department of Pathology, Mount Sinai Hospital, University of Toronto Medical School, Ontario, Canada.
R
R
Apel
Z
Z
Cohen
C W
CW
Andrews
R
R
McLeod
H
H
Steinhart
R D
RD
Odze
D000293:Adolescent; D000328:Adult; D001284:Atrophy; D002455:Cell Division; D003093:Colitis, Ulcerative / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D005260:Female; D006651:Histocytochemistry; D006801:Humans; D006965:Hyperplasia; D007082:Ileum / Q000378:metabolism / Q000473:pathology*; D007249:Inflammation; D007413:Intestinal Mucosa / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009077:Mucins / Q000378:metabolism; D016737:Proctocolectomy, Restorative; D011446:Prospective Studies; D013394:Sucrase-Isomaltase Complex / Q000378:metabolism
D009077:Mucins; D013394:Sucrase-Isomaltase Complex