A Preliminary Comparison of LiverBeads™ with a Conventional Rat Hepatocyte Culture Preparation: Some Aspects of Xenobiotic Metabolism and Related Toxicity

Abstract

LiverBeads™ are made of hepatocytes that are immobilised and cryopreserved in alginate gel. They have great potential as an easily transportable and easily handled source of hepatocytes for use in in vitro pharmacotoxicology. In this study, we compared the drug metabolising capacity of LiverBeads in culture with that of conventional cultures and of cultures derived from cryopreserved cells. Trypan blue exclusion, lactate dehydrogenase and DNA content were measured in LiverBead cultures. The levels were all similar to those of the conventional cultures, as were the toxicities of precocene II and allyl alcohol, although more variability was seen in the LiverBeads than in the conventional cultures. The cytochrome P450-dependent activity 3,4-dimethyl-7-ethoxycoumarin-O-dealkylase, was reduced in the LiverBeads when compared to the conventional cultures, although the pattern of conjugation was very similar. In addition, the inducibility of cytochrome P4504A was demonstrated in LiverBeads. Cultures from cryopreserved cells were more susceptible to the toxicants tested, and contained less lactate dehydrogenase and DNA than the conventional cultures. Overall, in terms of the aspects of drug metabolism measured, the cultures from LiverBeads appeared to be equivalent to conventional cultures, and superior to cultures from cryopreserved cells.

Metabolism: A Bottleneck in In Vitro Toxicological Test Development

“…Several physiologically relevant models have been established for liver cells, including co-cultures, by using primary cells attached to an extracellular matrix, such as collagen, as in sandwich cultures (102,103), or by using liver spheroids. The immobilisation of hepatocytes on alginate gel (Liverbeads™) or alginate biospheres has been shown to be a useful technique for studying the biotransforming capacity of hepatocytes (104,105). Choi et al (106) described a double-layered co-culture system, comprising two cell lines, Hep G2 and Caco-2, which showed a reduced Gonzalez & Tarloff (194).…”