INTESTINAL TRANSPLANTATION - EFFECTS ON ILEAL ENTERIC ABSORPTIVE PHYSIOLOGY

Background. The effects of small intestine transplantation on enteric physiology a-e poorly understood. After orthotopic jejunoileal autotra nsplantation, dogs develop a severe watery diarrhea and lose up to 15% of their body weight. The cause of these changes has not been explain ed. Our aim was to determine the influence of jejunoileal autotranspla ntation on ileal absorption of water, electrolytes, and bile salts and the effects of proabsorptive and prosecretory agents on ileal transpo rt. Methods. Seven dogs were studied before and at 2 and 8 weeks after in situ jejunoileal neural and lymphatic isolation (a model of small intestine autotransplantation). With a triple-lumen perfusion techniqu e, net ileal fluxes of water, electrolytes, and bile salts were measur ed before and at 2 and 8 weeks after this model of jejunoileal autotra nsplantation. In addition, the effects of an intravenous infusion of v asoactive intestinal polypeptide (a prosecretory agent) and norepineph rine (a proabsorptive agent) on net transport were evaluated. Results. Dogs developed a profuse diarrhea after this model of autotransplanta tion. Ileal absorption of water and electrolytes decreased immediately (measured during operation), remained decreased for 2 weeks, and retu rned toward baseline by 8 weeks. A similar decrease in net flux of bil e salts was shown at 2 weeks after transplantation and returned toward baseline by 8 weeks. The prosecretory response of vasoactive intestin al polypeptide on ileal fluxes of water and electrolytes was unchanged , whereas the proabsorptive response to norepinephrine increased after this model of autotransplantation. Conclusions. Jejunoileal autotrans plantation decreases ileal absorption of water, electrolytes, and bile salts. The profuse watery diarrhea observed in dogs after small intes tine autotransplantation may be a secretory and/or a bile salt-induced diarrhea related to the effects of jejunoileal denervation.