EFFECT OF A MODEL OF CANINE JEJUNOILEAL ORTHOTOPIC AUTOTRANSPLANTATION ON JEJUNAL AND ILEAL TRANSPORT OF WATER AND ELECTROLYTES

Canine jejunoileal transplantation induces an early profuse watery dia rrhea of uncertain etiology. Our aim was to determine the temporal eff ects of a canine model of jejunoileal autotransplantation (a model dev oid of confounding effects of ischemia-reperfusion or or immune reject ion) on basal jejunal and ileal absorption of water and electrolytes t o determine if impaired absorption is responsible for the diarrhea. Ou r hypothesis was that net absorption of water and electrolytes in an e nterically isolated loop would decrease after jejunoileal transplantat ion. Four groups of dogs (N greater than or equal to 6) were prepared with 80-cm modified Thiry-Vella loops: group I, neurally intact jejunu m; group II; autotransplanted jejunum; group III, neurally intact ileu m; and group IV autotransplanted ileum. The loops were perfused for 3 hr with 150 mM NaCl at 3 ml/min under fasted conditions; transit time through the loop was determined by bolus of a nonabsorbable marker. Do gs were studied on three separate days at one, two, eight, and nine we eks postoperatively. Net absorptive fluxes of water and electrolytes a nd transit times were similar (P > 0.05) between neurally intact and a utotransplant groups (group I vs II and group III vs IV) at each timep oint. Ileal loops absorbed more than jejunal loops, and transit was sl ower in ileal loops (each P < 0.05). Our findings suggest that, despit e the obligate disruption of extrinsic innervation, enteric (intrinsic ) neural continuity, and lymphatic drainage that accompanies this cani ne model of jejunoileal autotransplantation, net basal absorptive func tion of water and electrolytes during the fasted state was not decreas ed nor was transit altered either in jejunum or ileum. These findings have important implications for clinical small intestinal transplantat ion in man.