Human hepatocyte cell lines proliferating as cohesive spheroid colonies in alginate markedly upregulate both synthetic and detoxificatory liver function

Background/Aims: Bio-artificial liver support systems for treatment of hepatic failure require maintained expression of hepatocyte function in vitro. We studied cultures of human hepatocyte cell-lines proliferating within alginate beads, investigating the hypothesis that 3-dimensional cohesive colonies of hepatocyte cell-lines would achieve polarity and cell-to-cell contact resulting in upregulation of function. Methods: HepG2 and HHY41 human cell lines in alginate beads were cultured for >20 days. Results: Proliferation was maintained for 20 days. Production of albumin, prothrombin, fibrinogen, alpha-1-acid glycoprotein and alpha-l-antitrypsin was maintained throughout, maximal at days 8-10, when upregulation was 300-1100% compared with monolayer cultures at similar cell number per unit volume. Detoxificatory functions: ethoxyresorufin deethylase activity, androstenedione metabolism, and urea synthesis from arginine was also increased severalfold. Function returned to pre-freezing levels within 18 h of thawing after cryopreservation of cells in alginate, Electron microscopy revealed spherical colonies of cells of cuboidal shape, with cell-to-cell contact via desmosomes and junctional complexes, abundant microvilli, and cytoplasmic appearances suggesting transcriptionally active hepatocytes. Conclusion: Hepatocyte cell-lines, proliferating in alginate express a range of liver-specific functions at levels approaching those found in vivo, relevant to their use in liver support systems. (C) 2001 European Association for the Study of the Liver. Published by Elsevier Science B.V. All rights reserved.