Modifications in combined liver-small bowel transplantation in pigs

Early hemodynamics and metabolic changes after total abdominal evisceration for experimental multivisceral transplantation

PURPOSE: Multivisceral transplantation (MVTx) has been accepted as standard therapeutic modality for patients with short-bowel syndrome associated with irreversible liver failure. Even nowadays, experimental models of MVTx grounds high incidence of intraoperative or early recipient mortality. Despite the known deleterious effects of hepatosplanchnic exenteration the impact of this procedure on systemic hemodynamics and metabolism remains to be determined. METHODS: Nine dogs (20.1±0.5 kg) were subjected to an en bloc resection of all abdominal organs including, stomach, duodenum, pancreas, liver, spleen, small bowel, and colon. A woven double velour vascular graft was interposed between the suprahepatic and infrahepatic vena cava. Systemic hemodynamic were evaluated through a Swan-Ganz catheter, ultrasonic flowprobes, and arterial lines. Systemic O2-derived variables, glucose, and lactate metabolism were analyzed throughout the experiment. RESULTS: Complete abdominal exenteration was associated with significant reduction in cardiac output, and mean arterial pressure (57% and 14%, respectively). Two hours after reperfusion a significant reduction in arterial pH and glucose were also observed. Oxygen consumption remained unaltered during the first two hours of the experiment, with a significant increase of lactate levels (1.4±0.3 vs. 7.6±0.4, p<0.05). Three animals died before the 3 hours of reperfusion were completed. Total abdominal exenteration for MVTx in dogs is associated with early major hemodynamics, and metabolic changes. CONCLUSION: The deleterious hemodynamic alterations observed are probably related with the association of severe acidosis, hyperlactemia, hypoglycemia, and reduction of total circulating blood volume. Close hemodynamic and metabolic monitoring should be provided during experimental MVTx in order to promote an increase in successful rates of this complex and challenging procedure.

Immuno-protective effect of liver on small bowel in combined transplantation of liver and small bowel

AIM: To develop a new combined transplan-tation model of liver and small bowel in rats, and to investigate the protective effect of trans-planted liver on transplanted small bowel.

METHODS: Closed colony Sprague Dawley rats and inbred Wistar rats were included in this study. Five groups were designed: isogene small bowel transplant group (A), isogene liver transplant group (B), xenogene small bowel transplant group (C), xenogene liver transplant group (D), combined transplant of liver and small bowel group (E). Only Wistar rats were used in group A and B, while SD and Wistar rats were used as donors and recipients respectively in group C, D and E. During the combined transplantation of liver and small bowel (CTLS) for the donors, inferior vena cava in chest was cut to construct a muff in the lateral wall of portal vein and cuff was placed. During the operation for the recipients, portal veins of the donors and recipients were connected using cuff technique, and re-arterialization was completed by anastomosing the superior mesenteric artery of graft with the right kidney artery of the recipients. Randomly selected 4 rats from each group were sacrificed on postoperative days (POD) 5, 7 and 14, and grafts were sampled. The rejection of graft was investigated through histopathological analysis, and the apoptosis of the cells of graft were evaluated by TUNEL.

RESULTS: The survival rate of CTLS was 73.3% (22/30). The pathological changes of ischemia and reperfusion injury were observed in group A and B, and the numbers of apoptotic cells in the grafts were decreased with the prolonging of time. However, acute rejection after transplantation appeared in group C and D, and there were more apoptotic cells in the grafts. Mild, moderate and severe acute rejection occurred on POD 5, 7 and 14, respectively in group C, while only mild or severe acute rejection appeared in group E. Furthermore, the number of apoptotic cells in the grafts of group E was markedly decreased on POD 14 in comparison with that of group C (16.9 ± 4.3 vs 20.5 ± 6.3, P < 0.05). The degrees of acute rejection after transplantation and cell apoptosis of the grafts were not significantly different between group D and E.

CONCLUSION: The technique used in this study is feasible for establishment of CTLS model, and the transplanted liver can protect the transplanted intestinal graft from rejection in CTLS.