Serotonin (5-HT): an enteroendocrine marker of reperfusion injury after liver-small bowel allotransplantation in the pig.

HISTOMORPHOLOGIC and functional aspects of preservation/reperfusion injury, after small bowel transplantation, have been well investigated after different modalities and types of perfusion solutions. Experimental and clinical studies on bowel preservation damage have well defined the modifications of enteric and Goblet cells, vascular structures, myoenteric nerves, and ganglia. The enteroendocrine system is not so well studied. In recent studies of Lai et al, 1 on auxiliary small bowel allotransplantation in the dog without immunosuppression, biopsies of the small bowel were done daily and at time of death; specimens were stained with immunohistochemical methods for chromogranin A and somatostatin. Also, in animals with severe rejection, this type of enteroendocrine cell did not present any evident modification. Kaihara et al 2 suggested serotonin as a good marker of ischemia/reperfusion injury after allotransplantation of the small bowel in the rat. In their experience, the release of serotonin in the lumen bowel after reperfusion inversely correlated with the number and quality of serotonin cells. Our previous experiences with normothermic preservation in Ringer lactate solution, up to 20 hours in the pig, showed good preservation of argentaffin and serotonin cells up to 6 hours with a progressive marked reduction in the following hours. 3 The bowel perfused and preserved ipothermically with 4°C Wisconsin solution up to 36 hours, showed normal argentaffin cells up to 20 hours, after which time these cells were numerically reduced and degranulated. On the basis of these previous observations, we decided to analyze the modifications of enteroendocrine cells in a pig model of orthotopic liver-small bowel allotransplantation with different preservation/reperfusion times.