Hepatocyte cultures

Rat hepatocyte culture Unscheduled DNA synthesis No data - Hoechst 1984c... 

Morel et al. (1993) have reported that three flavanoids (catechin, quercetin and diosmetin) are cytoprotective on iron-loaded hepatocyte cultures. Their cytoprotective activity (catechin > quercetin > diosmetin) correlated with their iron-chelating ability (Morel et al., 1993). These compounds should also be good phenolic antioxidants so iron chelation may only be part of the story. 

Morel, I., Lescoat, G., Cogrel, P., Sergent, O., Pasdeloup, N., Brissot, P., Cillard, P. and Cillard, J. (1993). Antioxidant and iron chelating activities of the flavonoids catechin, quercetin and diosmetin on iron-loaded rat hepatocyte cultures. Biochem. Pharmacol. 45, 13-19. 

Numerous studies were dedicated to the effects of flavonoids on microsomal and mitochondrial lipid peroxidation. Kaempferol, quercetin, 7,8-dihydroxyflavone and D-catechin inhibited lipid peroxidation of light mitochondrial fraction from the rat liver initiated by the xanthine oxidase system [126]. Catechin, rutin, and naringin inhibited microsomal lipid peroxidation, xanthine oxidase activity, and DNA cleavage [127]. Myricetin inhibited ferric nitrilotriacetate-induced DNA oxidation and lipid peroxidation in primary rat hepatocyte cultures and activated DNA repair process [128]. 

Chelators of iron, which are now widely applied for the treatment of patients with thalassemia and other pathologies associated with iron overload, are the intravenous chelator desferal (desferrioxamine) and oral chelator deferiprone (LI) (Figure 19.23, see also Chapter 31). Desferrioxamine (DFO) belongs to a class of natural compounds called siderophores produced by microorganisms. The antioxidant activity of DFO has been studied and compared with that of synthetic hydroxypyrid-4-nones (LI) and classic antioxidants (vitamin E). It is known that chronic iron overload in humans is associated with hepatocellular damage. Therefore, Morel et al. [370] studied the antioxidant effects of DFO, another siderophore pyoverdin, and hydroxypyrid-4-ones on lipid peroxidation in primary hepatocyte culture. These authors found that the efficacy of chelators to inhibit iron-stimulated lipid peroxidation in hepatocytes decreased in the range of DFO > hydroxypyrid-4-ones > pyoverdin. It seems that other siderophores are also less effective inhibitors of lipid peroxidation than DFO [371],... 

Negative results for mutagenicity of d.v-chlordanc and tran.v-chlordanc were reported in various strains of bacteria and in hepatocyte cultures of small mammals. But technical chlordane proved mutagenic to selected strains of Salmonella typhimurium and induced gene conversions in certain strains of the yeast, Saccharomyces cervisiae (IARC 1979 USEPA 1980, 1988 WHO 1984). 

Kennedy, S.W., A. Lorenzen, C.A. James, and R.J. Norstrom. 1992. Ethoxyresorufin-O-deethylase (EROD) and porphyria induction in chicken embryo hepatocyte cultures — a new bioassay of PCB, PCDD, and related chemical contamination in wildlife. Chemosphere 25 193-196. 

Donateo, M.T., Gomez-Lechon, M.J., and Castell, J.V. 1993. A microassay for measuring cytochrome P450IA1 and P450IIB1 activities in intact human and rat hepatocytes cultured on 96-well plates. Anal. Biochem. 213 29. 

Primary hepatocyte cultures have been used as a tool to predict the hepatotoxicity of many compounds such as nonsteroidal anti-inflammatory drugs (Castell et ah, 1988), psychotropic drugs (Boelsterli et ah, 1987), immunosuppressant drugs (Boelsterli et ah, 1988), and salicylates (Tolman et ah, 1978). Rat primary hepatocyte cultures have also been shown to be a good model for examining the mechanisms of metallothionein-induced tolerance to cadmium toxicity (Liu et ah,... 

Comparative Metabolism. Since the liver is the major organ involved in the biotransformation of xenobiotics, primary hepatocyte cultures provide an excellent model for in vitro metabolism studies. Primary hepatocyte cultures provide useful tools with which to study the comparative metabolism of xenobiotics by both humans and laboratory animals. 

Green et al. (1986) compared the metabolism of amphetamine in isolated hepatocyte suspensions from rat, dog, squirrel, monkey, and human livers. The metabolite profile of hepatocytes from each species corresponded to the profile of urinary metabolites identified previously. These results indicate that species-specific differences in the metabolic activation of compounds seen in vivo can be reproduced in vitro by the utilization of primary hepatocyte cultures. 

Primary hepatocyte cultures have been used in vitro to metabolically activate toxins for evaluation with target tissues. Cocultures of rat embryos with hepatocytes have been used to study the role of metabolism in teratogenesis (Oglesby et al., 1986). Lindahl-Kiessling et al., (1989), in an attempt to bring test conditions closer to in vivo conditions, developed an assay utilizing primary rat hepatocytes and human peripheral lymphocytes to detect metabolism-mediated mutagenesis. 

TABLE 17.4. In Vitro Testing Utilizing Hepatocyte Cultures... 

Boelsterli, U.A., Bouis, P., Brouillard, J.F. and Donatsch, P. (1988). In vitro toxicity assessment of cyclosporin A and its analogs in a primary rat hepatocyte culture model. Toxicol. Appl. Pharmacol. 96 212-221. 

Hockin, L.J. and Paine, A.J. (1983). The role of 5-aminolevulinate synthetase, haem oxygenase and ligand formation in the mechanism of maintenance of cytochrome P-450 concentration in hepatocyte culture. Biochem. Pharmacol. 210 855-857. 

Liu, J., Kershaw, W.C. and Klaasen, C.D. (1990). Rat primary hepatocyte cultures are a good model for examining metallothionein-induced tolerance to cadmium toxicity. In Vitro Cell. Dev. Biol. 26 75-79. 

Smolarek, T.A., Higgings, C.V and Amacher, D.E. (1990a). Metabolism and cytotoxicity of acetaminophen in hepatocyte cultures from rat, rabbit, dog and monkey. Drug Metabolism and Disposition 18 659-663. 

Fischer 344 rat primary hepatocyte cultures (DNA repair) DNA damage — NA Maslansky and Williams 1981... 

Probst GS, McMahon RE, Hill LE, et al. 1981. Chemically-induced unscheduled DNA synthesis in primary rat hepatocyte cultures A comparison with bacterial mutagenicity using 218 compounds. Environ Mutagen 3 11-32. 

Bolognesi C, Taningher M, Parodi S, et al. 1986. Quantitative predictivity of carcinogenicity of the autoradiographic repair test (primary hepatocyte cultures) for a group of 80 chemicals belonging to different chemical classes. Environ Health Perspect 70 247-53. 

Sergent, O., Griffon, B., Morel, I., Chevanne, M., Dubos, M. P., Cihard, P., and Chlard, J., 1997, Effect of nitric oxide on iron-mediated oxidative stress in primary rat hepatocyte culture, Hepatology 25 122-127. 

Berthiaume, F., Moghe, P.V., Toner, M. and Yarmush, M.L. (1996) Effect of extracellular matrix topology on cell structure, fimction, and physiological responsiveness hepatocytes cultured in a... 

Hepatocytes Culture methods available Full enzyme complement - contain enzymes and enzyme cofactors not present in subcellular fractions Full enzyme complement - contain enzymes and enzyme cofactors not present in subcellular fractions Can be used quantitatively Useful for prediction of Phase 1 and 11 metabolism Require fresh tissue No cell-cell contact Need collagenase digestion Handling difficult Closed system so may not be representative of in vivo situation... 

---