Neonatal Livers: A Source for the Isolation of Good-Performing Hepatocytes for Cell Transplantation

Abstract

Hepatocyte transplantation is an alternative therapy to orthotopic liver transplantation for the treatment of liver diseases. However, the supply of hepatocytes is limited given the shortage of organs available to isolate good-functioning quality cells. Neonatal livers may be a potential source alternative to adult livers to obtain good-performing hepatic cells for hepatocyte transplantation, which has not yet been explored profoundly. High-yield preparations of viable hepatocytes were isolated from 1- to 23-day-old liver donors, cryopreserved, and banked. Cell integrity and functional quality assessment were performed after thawing. Neonatal hepatocytes showed better postthawing recovery compared with adult hepatocytes, as shown by the viability values that did not differ significantly from freshly isolated cells, a higher expression of adhesion molecules (β1-integrin, β-catenin, and E-cadherin), better attachment efficiency, cell survival, and a lower number of apoptotic cells. The metabolic performance of thawed hepatocytes has been assessed by ureogenesis and drug-metabolizing capability (cytochrome P450 and UDP-glucuronosyltransferase enzymes). CYP2A6, CYP2C9, CYP2E1, and CYP3A4 activities were found in all cell preparations, while CYP1A2, CYP2B6, CYP2C19, and CYP2D6 activities were detected only in hepatocytes from a few neonatal donors. The expression of UGT1A1 and UGT1A9 (transcripts and protein) was detected in all hepatocyte preparations, while activity was measured only in some preparations, probably due to lack of maturity of the enzymes. However, isoforms UGT1A6 and UGT2B7 showed considerable activity in all preparations. Compared to adult liver, the hepatocyte isolation procedure in neonatal livers also provides thawed cell suspensions with a higher proportion of hepatic progenitor cells (EpCAM(+) staining), which could also participate in regeneration of liver parenchyma after transplantation. These results could imply important advantages of neonatal hepatocytes as a source of high-quality cells to improve human hepatocyte transplantation applicability.