Jejunal and ileal absorptive function after a model of canine jejunoileal autotransplantation

The effects of intestinal transplantation on the physiologic functions of the gut are not well understood. Our aim was to determine the effect of a large animal model of small intestinal transplantation (disruption of all neural and lymphatic continuity) on selected absorptive functions of the jejunoileum. Seven dogs were studied before and at 1, 4, and 12 weeks after a model of jejunoileal autotransplantation, which avoids confounding factors of immune rejection, immunosuppression, and harvest ischemia. Jejunal function was assessed by quantitative [³H]-folate and d-xylose absorption and ileal function by quantitative ⁵⁷Co-vitamin B₁₂ absorption. The role of lymphatic continuity was assessed by fecal fat recovery following 5 days of a controlled, high fat diet (75 g/day). All dogs developed a profuse, watery diarrhea that persisted for 6 to 12 weeks and lost about 15% body weight; however, absorption of d-xylose, folate, and vitamin B₁₂ was unaffected at any time point. Fat absorption postoperatively was only mildly abnormal (≤8 g/day) at all time points in five of seven dogs despite complete lymphatic disruption. We concluded that jejunoileal autotransplantation does not markedly affect these specific jejunoileal absorptive functions. Fat absorption in most dogs surprisingly remains almost normal. Anatomic and physiologic consequences of intestinal transplantation do not appear to induce global abnormalities in all absorptive functions in the nonrejecting jejunoileum.