Hepatocyte function during experimental use of a bioartificial liver

Abstract

The aim of the present study was to compare the function of fresh versus cryopreserved hepatocytes in an experimental bioartificial liver system (BAL), especially designed to reproduce clinical parameters. Our BAL consists of a pump, a plasma reservoir, a membrane oxygenator, and a hollow fiber module loaded with 5 × 10 9 isolated porcine hepatocytes, either fresh (n = 5) or cryopreserved (n = 5). In the present setting, the system was isolated and perfused for 6 hours with recirculating plasma obtained from pigs with ischemic liver failure (toxic plasma). The following parameters were studied at 0 and 6 hours: oxygen consumption by the hepatocytes in the bioreactor, hepatocyte viability, as well as plasma concentrations of AST, LDH, ammonia, urea, and total bilirubin. MEGXconcentrations were measured following injection of lidocaine into the system 30 minutes after initiation of plasma recirculation. Compared to cryopreserved cells, fresh hepatocytes showed higher viability at both time points studied ( P < .05). Furthermore, during BAL sessions, ammonia levels were reduced while urea, AST, and LDH levels were increased with both preservation types ( P < .05). Total bilirubin levels increased only during sessions with cryopreserved hepatocytes. After lidocaine administration, both fresh and cryopreserved hepatocytes were capable of producing MEGX; however, fresh-cell bioreactors produced significantly more MEGX at both 30 and 60 minutes after lidocaine administration. Oxygen consumption was significantly higher by fresh-cell bioreactors both before and after BAL use. In conclusion, hepatocytes in the BAL bioreactor showed preservation of important metabolic functions, when perfused with homologous toxic plasma. Fresh cells appeared to respond better than did cryopreserved ones.