Enzymes activity of intestinal grafts after liver small bowel transplantation in rats

OBJECTIVES: To investigate the activity alterations of enzymes in intestine grafts after liver/small bowel transplantation in rats and the relations of these changes to immune rejection of grafts. METHODS: A model of liver/small bowel transplantation (LSBT) was established in closed colony SD and Wistar rats. The activity of enzymes including triphosphatase (ATPase), alkalinophosphatase (AKP), acytelcholinesterase (AchE), oxidesynthase (NOS) and monoamine oxidase (MAO) in bowel grafts was studied histochemically at regular postoperative intervals. RESULTS: The activity of enzymes in the wall of the grafts disappeared eventually in isolated small bowel transplantation (SBT) rats. In contrast, the activity in LSBT rats remained and recovered postoperatively. CONCLUSIONS: The rejection in grafted intestine could be prevented or delayed in LSBT rats. The changes in the activity of enzymes and neurons might be used to detect the rejection and function of the graft.

Gut microbiota and its implications in small bowel transplantation

The gut microbiota is mainly composed of a diverse population of commensal bacterial species and plays a pivotal role in the maintenance of intestinal homeostasis, immune modulation and metabofism. The influence of the gut microbiota on solid organ transplantation has recently been recognized. In fact, several studies indicated that acute and chronic allograft rejection in small bowel transplantation （SBT） is closely associated with the alterations in microbial patterns in the gut. In this review, we focused on the recent findings regarding alterations in the microbiota following SBT and the potential roles of these alterations in the development of acute and chronic allograft rejection. We also reviewed important advances with respect to the interplays between the microbiota and host immune systems in SBT. Furthermore, we explored the potential of the gut microbiota as a microbial marker and/or therapeutic target for the predication and intervention of allografl rejection and chronic dysfunction. Given that current research on the gut microbiota has become increasingly sophisticated and comprehensive, large cohort studies employing metagenomic analysis and multivariate linkage should be designed for the characterization of host-microbe interaction and causality between microbiota alterations and clinical outcomes in SBT. The findings are expected to provide valuable insights into the role of gut microbiota in the development of allograft rejection and other transplant-related complications and introduce novel therapeutic targets and treatment approaches in clinical practice.

Immunological protection of small bowel by simultaneously transplanted liver graft in pigs

BACKGROUND: A simultaneously transplanted liver shields a bowel graft from immunologic attack in small animals, while the possible immuno-tolerance induced by the liver in liver and small bowel transplantation (LSBT) is uncertain in large animal models. To investigate the clinically suspected beneficial effect of the liver on small bowel allograft, we developed a new model of composite LSBT in the pig. METHODS: Seventy outbred long-white pigs were randomized into four groups. LSBT without immunosuppressive treatment (n=10, group A); LSBT with routine immunosuppressive treatment (n=10, group B); LSBT with a lower dose of immunosuppressive treatment (n=10, group C); and small bowel segment allotransplantation without immunosuppressive treatment (n=10, group D). RESULTS: There was no remarkable difference in survival time between groups A and D (10.33 vs. 12.89 days, P>0.05), but the initial time of acute rejection of the intestinal graft in group A was clearly delayed when compared to group D (8.22 vs. 4.33 days, P<0.05), and the rejection scores in group A were remarkably lower than those in group D at each postoperative time point (0 vs. 0.44 on day 3, P<0.05; 0.22 vs. 1.78 on day 5, P<0.05; 1.11 vs. 2.56 on day 7, P<0.05). There were evident differences in postoperative survival time, initial time of acute rejection and postoperative rejection scores between groups A, B and C. Postoperative survival time (30.00 vs. 28.13 days, P>0.05), initial acute rejection time (25.40 vs. 22.13 days, P>0.05) or rejection score did not differ between groups B and C within one postoperative month. CONCLUSIONS: Compared to isolated segment small bowel allotransplantation, the intestinal graft in LSBT (group A) had a delayed initial time of acute rejection and a lower postoperative acute rejection score, and a lower dose of immunosuppressive treatment led to persistent graft immuno-tolerance in LSBT. Thus the simultaneously transplanted liver graft may reduce the risk of intestinal rejection and protect the bowel graft from severe acute rejection.