Metabolic substrate utilization differs in ileal faecal and urinary reservoirs.
BACKGROUND
Construction of an ileal faecal or urinary reservoir profoundly alters ileal luminal ecology and availability of mucosal metabolic substrates. The aims of this study were to measure mucosal metabolic flux of butyrate and glutamine in histologically normal (control) ileum and to determine the effect of reservoir construction on metabolic fluxes in patients with ileal pouch-anal anastomosis and ileocystoplasty.


METHODS
Endoscopic biopsy samples were obtained from normal ileum (n = 10), ileum of patients with ulcerative colitis (n = 10), ileal pouch-anal anastomosis (n = 7), ileocystoplasty (n = 7) and ileal conduit (n = 7). Using a closed microculture technique, biopsy utilization of 14C-labelled butyrate and glutamine was measured as [14C]carbon dioxide production. Biopsy DNA content was measured and [14C]carbon dioxide evolution expressed as picomoles [14C]carbon dioxide per microgram DNA per hour.


RESULTS
The metabolic flux of both butyrate and glutamine was reduced in ileal pouch mucosa compared with that of ileal mucosa in patients with ulcerative colitis. In contrast, the metabolic flux of buyrate alone was reduced in ileal mucosa from ileocystoplasty and ileal conduit compared with that in normal ileal mucosa, while the metabolic flux of glutamine remained unchanged.


CONCLUSIONS
Ileal mucosal metabolic fluxes measured in vitro are altered by changing luminal ecology in vivo. These changes may affect the health and mucosal integrity of ileum used to construct these reservoirs.
Department of Biochemistry, Mater Misericordiae Hospital and University College Dublin, Ireland.
M M
MM
Duffy
M C
MC
Regan
M G
MG
Harrington
J M
JM
Fitzpatrick
P R
PR
O'Connell
D002087:Butyrates / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D003093:Colitis, Ulcerative / Q000378:metabolism / Q000601:surgery*; D003110:Colonic Neoplasms / Q000378:metabolism / Q000601:surgery*; D005973:Glutamine / Q000378:metabolism*; D006801:Humans; D007082:Ileum / Q000378:metabolism / Q000637:transplantation*; D007413:Intestinal Mucosa / Q000378:metabolism; D016737:Proctocolectomy, Restorative; D016476:Urinary Reservoirs, Continent
D002087:Butyrates; D005973:Glutamine; D002245:Carbon Dioxide