Construction of Liver Model with Genetically Engineered Human HepG2 Cells

Abstract

Bioartificial liver (BAL) support systems are currently expected to be novel therapeutic devices for the end stage of hepatic failure. Treatment with BAL systems will improve recipient conditions as a bridge to successful transplantation and will support the critical stage of the post-operational period. We developed a BAL system containing the human hepatoblastoma cell line HepG2 with the addition of an ammonia removal function by transfecting a glutamine synthetase (GS) gene. After transfection of a hamster GS gene into HepG2, the resulting GS-HepG2 cells showed 15% ammonia removal activity of porcine hepatocytes, while unmodified HepG2 cells had no such activity. The established GS-HepG2 cells were grown in a circulatory flow bioreactor and used when the cell numbers reached 3.5 – 4.1 × 109. We used pigs with ischemic liver failure to estimate the efficiency of the BAL system. The BAL treatment was started 3 hrs after the completion of total liver ischemia. The survival time of the animals treated with GS-HepG2 BAL was significantly longer than that of the cell-free control group (14.5 hrs vs. 8.5 hrs) and the group treated with BAL consisting of unmodified HepG2 (9.6 hrs). The BAL groups containing the GS-HepG2 cells had significantly fewer incidents of increased brain pressure and abnormalities of coagulation indices during the plasma exchange treatment.