A NOVEL PORCINE MODEL OF IN SITU SUB-TOTAL (70%) DONOR HEPATECTOMY AND ORTHOTOPIC TRANSPLANTATION (Tx) OF THE REMAINING LIVER GRAFT.

Abstract

418 PURPOSE OF THE STUDY: In patients with liver failure, replacement of the diseased organ is currently the only available therapeutic modality. It has been argued that in the face of reduced cadaveric organ donation with progressive increase in the number of patients awaiting liver Tx, obtainment of sections of livers from living-related donors (LRD) and splitting cadaveric organs may help alleviate this shortage. While Tx of left lateral segment obtained from LRD may be adequate for pediatric recipients, its relatively small size is considered inadequate to meet the physiological needs of that of an adult. To formally address this issue, we proceeded to develop a porcine model of liver Tx, in which, the donors were subjected (in situ) to subtotal (70%) hepatectomy with obtainment of the remaining (30%) graft for orthotopic placement in a syngeneic recipient. It was envisioned that if successful, this model would also allow us to undertake studies aimed at elucidating the mechanisms underlying liver regeneration. METHODS: White female pigs weighing 28-32 kg were used as donors and recipients. Donor Surgery, 70% hepatectomy was performed by in situ resection of left and central lobes (LCL). The hepatic pediclas to the LCL were isolated and divided by the glissonian approach. Along a well-demarcatod line, the parechyma was dissected using an ultrasonic dissector. Isolating and ligating the hepatic veins draining the LCL completed the resection. At the culmination of this procedure, right hepatic and candate lobes with intact blood supply and biliary drainage were preserved. This partial (30%) graft was then harvested following perfusion of the aorta and portal vein with chilled lactated Ringer's solution. Subsequent to procurement, the graft was weighed and the percentage of liver volume and total body weight was calculated. Additionally, harvested livers were also subjected to cholangiography to confirm the integrity of the biliary tree. The reduced (30%) graft was then orthotopically transplanted into a syngeneic recipient in whom, liver function was serially monitored post-Tx. The cold ischemia time was maintained at < 2 hours; blood loss was minimal. RESULTS: Without any further intervention, animal and graft survival was observed in syngeneic recipients of reduced (30%) orthotopic livers. CONCLUSIONS: Unlike the prevailing dogma, orthotopic Tx of reduced livers may be able to sustain the physiological and metabolic needs of majority of adult transplant recipients. However, the putative use of hepatic growth factors to augment regeneration of transplanted livers may allow widespread utility of this approach in clinical organ Tx. The latter approach is currently under investigation.