Water transport in native and transplanted porcine jejunum

Adequate absorptive function of transplanted small intestine is essential for success of this procedure. This study compared water transport under basal and meal stimulated conditions in the transplanted swine jejunum to native jejunum. Six female adolescent Yorkshire swine were randomized to undergo construction of either a 25-cm native proximal jejunal Thiry-Vella Fistula (TVF), n=3, or a 25-cm proximal jejunal allograft TVF, n=3. Immunosuppression in the transplanted animals was accomplished with intravenous methylprednisolone, azathioprine, and cyclosporin. Jejunal absorption studies, each 4 hr long, were performed utilizing 14C-polyethylene glycol to calculate net water flux. Each animal underwent at least three fasting and three postprandial studies. New water flux was negative, i.e., secretory, in both the native and transplanted proximal swine jejunum. In the basal state, integrated hourly water transport was more secretory in the native bowel vs the transplanted bowel during the 2nd, 3rd, and 4th experimental hr (-4.6 +/- .8 vs -2.1 +/- .7 cc, P = 0.034; -4.4 +/- .7 vs -1.8 +/- .6 cc, P = 0.012; and -4.7 vs 1.3 +/- .5 cc, P < 0.005), respectively. In native jejunum, integrated hourly water transport was less secretory 2 and 3 hr postprandially compared to basal (-1.9 +/- .5 vs -4.4 +/- .7 cc, P = 0.016; and -2.0 +/- .5 vs -4.7 +/- .7 cc, P = 0.021), respectively. This postprandial proabsorptive response did not occur in the transplanted jejunum. Native and transplanted jejunal water flux in the postprandial state did not differ significantly. We conclude that there is higher secretion in native vs transplanted jejunum during fasting. The postprandial proabsorptive response of the proximal porcine jejunum is abolished by transplantation.