Mario Alessiani¹, Lorenzo Cobianchi¹, Sandro Zonta¹, Jacopo Viganò¹, Tommaso Dominioni¹, Patrizia Morbini², Andrea Bottazzi³, Paolo Dionigi¹

¹Surgery, Fondazione IRCCS Policlinico San Matteo, University of Pavia, Pavia, Italy; ²Pathology, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy; ³Anesthesiology, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy

An increasing number of patients are listed for intestinal (isolated or combined with other organs) transplantation. Consideration for extended donor criteria has been suggested to increase donation. Living intestine donation, extention of acceptable donor criteria, optimized donor allocation and donation after cardiac death (NHB) are taken into consideration for this purpose.

We have studied, in an experimental setting of small bowel transplantation, the feasibility of using intestinal grafts undergoing a short warm ischemia time before cold perfusion, mimicking NHB donors. 25 Large White piglets underwent total orthotopic small bowel transplantation and were randomly divided into two groups: group 1 (n=15) received grafts after 20 minutes of warm ischemia followed by cold perfusion; group 2 (n=10) received grafts after conventional cold perfusion. In both groups immunosuppression was based on tacrolimus oral monotherapy. The animals were observed for 30 days. Postoperative studies included evaluation of graft absorptive function (D-xylose test), histological investigation with sequential biopsies, blood levels monitoring of inflammatory cytokines. The median survival was 19,2 ±9,7 days in group 1 and26,8 ±7,5 in group 2. Intestinal failure was seen only in group 1, causing the death of 40% of animals. The histological examination revealed a statistically significant difference between the two groups in terms of ischemia/reperfusion injury (IRI) (Park/Chiu score, p<0,05). The cytokines blood levels were significantly increased in group 1. In this latter group intestinal absorption was also impaired.

Our study confirm that intestinal mucosa is very sensitive to warm ischemic injury and that, without any treatment to reduce graft IRI, NHB donation is not feasible for small bowel transplantation. However our findings indicate that protective strategies against IRI could be effective to reduce or prevent irreversibile damage due to warm ischemia and are under evaluation in our experimental model.