Partial hepatectomy and laparoscopic-guided liver biopsy in rhesus macaques (Macaca mulatta): Novel approach for study of liver regeneration

Background and Purpose: Although valuable information has been gained using a rodent partial hepatectomy model to assess liver regeneration, the abili ty to apply this research to humans remains uncertain. Thus, liver regenera tion was assessed in a non-human primate, the rhesus macaque (Macaca mulatt a). Methods: One animal underwent 60% hepatectomy, a second animal underwent 30 % hepatectomy, and control surgery (cholecystectomy) was performed on two s eparate animals. Laparoscopic-guided liver biopsy was performed on days 1, 2, 7, 14, and 30 after surgery. Changes in hemoglobin concentration and ala nine transaminase activity were assessed, and liver regeneration was evalua ted by measuring the expression of Ki-67. Results: All animals survived surgery and laparoscopy. Substantial liver re generation was induced in the animal that underwent 60% hepatectomy. Excell ent tissue specimens were obtained via laparoscopic-assisted liver biopsy. Conclusions: Sixty percent partial hepatectomy in rhesus macaques appears t o be an excellent model for the study of hepatocellular regeneration. The p rocedure was safe, and effectively induced liver regeneration. In addition, laparoscopic-guided liver biopsy allows observation of changes in the live r remnant as regeneration develops, and provides excellent tissue specimens for analysis. Thus, this rhesus macaque partial hepatectomy model will all ow further characterization of liver regeneration in a species closer to hu mans.