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Background & Aims: The main hindrance in promoting living donor liver transplantation remains the morbi-mortality risk for the donor. Considering the opposed remodeling influence of portal and hepatic artery flows, our working hypothesis was to identify a lobar portal vein stenosis capable of inducing a contralateral liver mass compensatory enlargement, without the downstream ipsilateral atrophic response. Methods: Twenty-four pigs entered this study. Six of them were used to establish hemodynamic changes following a progressive left portal vein (LPV) stenosis, in blood flow, pressure and vessel diameter of the LPV, main portal vein and hepatic artery. Sixteen pigs were divided into 4 groups: sham operated animals, 20% LPV stenosis, 50% LPV stenosis, and 100% LPV stenosis. Daily liver biopsies were collected until post-operative day 5 to investigate liver regeneration and atrophy (Ki67, STAT3, LC3, and activated caspase 3) according to the degree of LPV stenosis. Finally, changes in liver volumetry after 20% LPVS were investigated. Results: A 20% LPV stenosis led to dilatation of the hepatic artery and a subsequent four-fold increase in hepatic arterial flow. Concomitantly, liver regeneration was triggered in the non-ligated lobe and the cell proliferation peak, 5days after surgery, was comparable to that obtained after total LPV ligation. Moreover, 20% LPV stenosis preconditioning did not induce left liver atrophy contrary to 50 and 100% LPV stenosis. Conclusions: A 20% LPV stenosis seems to be the adequate preconditioning to get the remnant liver of living donor ready to take on graft harvesting without atrophy of the future graft. [Copyright &y& Elsevier]

Abstract: Objective: The aim of the present study was to validate an experimental model of heterotopic renal allotransplantation. Such a model, more relevant to the human situation, has never been previously described. Materials and Methods: Pietrin pigs (40 to 50 kg) were used in the study. Through a midline incision, the left kidney was removed, washed, and preserved in a standard preservation solution (Celsior, Genzyme, France) for 20 hours at 4°C. Heterotopic autotransplantation was performed into the right iliac fossa onto the external iliac vessels with an end-to-side anastomosis and a nonstented uretero-ureteral anastomosis was performed. Results: Twenty-five renal allotransplantations were performed over a 5-month time period. Mean operating time progressively decreased and stabilized after 15 procedures (mean ± SD: 78.2 ± 19 minutes and 187.4 ± 18 minutes for left nephrectomy and transplantation, respectively) as morbidity decreased concomitantly. Suturing times for end-to-side anastomosis of the renal artery and vein onto the external iliac artery and vein were 21.9 ± 7 minutes and 34 ± 8 minutes (mean ± SD), respectively. Ten pigs died before the end of the experiment. ConcIusions: We have developed and validated the first nonrodent animal model of heterotopic renal autotransplantation relevant to the human anatomy and physiology. The procedure was easy to learn and safe. This model could be used to teach junior surgeons renal transplantation techniques and could also be used as a model to study ischemia-reperfusion injury in renal transplantation. [Copyright &y& Elsevier]