Cellular Liver Regeneration After Extended Hepatic Resection in Pigs
Ruth Ladurner*, Martin Schenk, Frank Traub, Alfred Koenigsrainer, Jorg Glatzle
General and Transplant Surgery, University of Tuebingen, Tuebingen, Germany
Background: The liver has an extremely effective regenerative capacity. There is some evidence, that a portosystemic shunt is beneficial for liver regeneration after extended resection. The aim of the study was to estimate, whether the regeneration is due to hypertrophy or hyperplasia of the remnant liver tissue and whether a portosystemic shunt is beneficial for liver regeneration. MATERIAL AND
Methods: An extended left hemihepatectomy (approximately 75% of liver volume) was performed in 6-8 weeks old domestic pigs (n=25, body weight 25-35 kg). In n=14 pigs a portosystemic H-shunt was inserted between the portal vein and the infrahepatic cava vein after extended resection. After surgery, animals were weaned from anesthesia and resumed oral feeding. Liver biopsies were histological examined before extended liver resection and weekly until the 3rd postoperative week. Liver regeneration was estimated by the liver volume, the size of the portal fields [mm2], the amount of hepatocytes per portal field and the amount of hepatocytes per mm2.
Results: Extended left resection was technically feasible in all animals with and without portosystemic shunt. Volume of the remnant right lateral segment reached 250% at the end of the first week after resection. The size of the portal fields increased significantly after resection (portal field [mm2]; animals with shunt before resection: 1.0±0.4, 1 week after resection: 1.8±0.9*; 3 weeks: 2.9±1.3*, *p<0.05; animals without shunt before resection: 1.1±0.3, 1 week after resection 1.8±0.7*; 3 weeks: 2.9±1.7*, *p<0.05). The number of hepatocytes in the portal fields increased significantly (hepatocytes/portal field, animals with shunt before resection: 3438±1281; 1 week after resection: 5831±3419*; 3 weeks: 8793±3690*; *p<0.05; animals without shunt before resection: 3053±1096, 1 week after resection: 4580±2007*; 3 weeks: 8014±4809*, *p<0.05). Interestingly there was no increase in hepatocytes/mm2 and there was no difference between animals with or without portosystemic shunt.
Conclusion: After extended liver resection the restoration of the liver volume is accomplished by an extensive and significant hyperplasia of hepatocytes within the preexisting portal fields, indicated by increased portal fields and hepatocytes per portal field, but constant hepatocytes per mm2. However, there was no beneficial effect of a portosystemic shunt, regarding liver regeneration after extended liver resection.
