Adult Liver Slices Research Articles

Efficient replication of primary or culture hepatitis C virus isolates in human liver slices: A relevant ex vivo model of liver infection

The development of human cultured hepatitis C virus (HCV) replication-permissive hepatocarcinoma cell lines has provided important new virological tools to study the mechanisms of HCV infection; however, this experimental model remains distantly related to physiological and pathological conditions. Here, we report the development of a new ex vivo model using human adult liver slices culture, demonstrating, for the first time, the ability of primary isolates to undergo de novo viral replication with the production of high-titer infectious virus as well as Japanese fulminant hepatitis type 1, H77/C3, and Con1/C3. This experimental model was employed to demonstrate HCV neutralization or HCV inhibition, in a dose-dependent manner, either by cluster of differentiation 81 or envelope protein 2-specific antibodies or convalescent serum from a recovered HCV patient or by antiviral drugs. This new ex vivo model represents a powerful tool for studying the viral life cycle and dynamics of virus spread in native tissue and also allows one to evaluate the efficacy of new antiviral drugs.

Effect of maternal ethanol consumption on foetal and neonatal rat hepatic protein synthesis

Effects of maternal ethanol consumption were investigated on the rates of protein synthehsis by livers of foetal and neonatal rats both in vivo and in vitro, and on the activities of enzymes involved in protein synthesis and degradation. The rates of general protein synthesis by ribosomes in vitro studied by measuring the incorporation of [14C]leucine into ribosomal protein showed that maternal ethanol consumption resulted in an inhibition of the rates of protein synthesis by both foetal and neonatal livers from the ethanol-fed group. The rates of incorporation of intravenously injected [14C]leucine into hepatic proteins were also significantly lower in the foetal, neonatal and adult livers from the ethanol-fed group. Incubation of adult-rat liver slices with ethanol resulted in an inhibition of the incorporation of [14C]leucine into hepatic proteins; however, this effect was not observed in the foetal liver slices. This effect of externally added ethanol was at least partially prevented by the addition of pyrazole to the adult liver slices. Pyrazole addition to foetal liver slices was without significant effect on the rates of protein synthesis. Cross-mixing experiments showed that the capacity of both hepatic ribosomes and pH5 enzyme fractions to synthesize proteins was decreased in the foetal liver from the ethanol-fed group. Maternal ethanol consumption resulted in a decrease in hepatic total RNA content, RNA/DNA ratio and ribosomal protein content in the foetal liver. Foetal hepatic DNA content was not significantly affected. Ethanol consumption resulted in a significant decrease in proteolytic activity and the activity of tryptophan oxygenase in the foetal, neonatal and adult livers. It is possible that the mechanisms of inhibition of protein synthesis observed here in the foetal liver after maternal ethanol consumption may be responsible for at least some of the changes observed in 'foetal alcohol syndrome'.

Effect of cell concentration on the uptake of amino acids by rat liver parenchymal cells in suspension.

The accumulation of several amino acids in the acid-soluble fraction and their incorporation into protein in rat liver parenchymal cell suspensions, has been shown to depend on the concentration of cells in the incubation medium; the uptake, both in the acid-soluble and the acid-insoluble fractions, decreased as the cell concentration increased from 0.03 X 10(6) cells/ml upwards, reaching a plateau at high cell concentrations (3-5 X 10(6) cells/ml). The uptake values at high cell concentrations were the same as those obtained in liver slices in which a similar effect was not observed. Evidence is presented which suggests that this phenomenon is mediated by a material released from the cells in suspension, which is inhibitory to enhancement of the uptake of amino acids by these cells over and above the value obtained in normal, adult liver slices.

The oxidation of choline by liver slices and mitochondria during liver development in the rat

Betaine is the major oxidation product of [Me- 14C] choline produced by rat liver slices. Liver slices from adult rats rapidly oxidize [Me- 14C] choline to betaine and the bulk of the betaine produced is recovered in the incubation medium. Considerably more choline is oxidized to betaine than is phosphorylated to phosphorylcholine. The rate of phosphorylation of choline appears to be independent of the rate of choline oxidation. Liver slices from fetal and young rats oxidize choline to betaine at a lower rate than adult liver slices. The ability of mitochondria to oxidize [Me- 14C] choline to betaine aldehyde and betaine is considerably lower in fetal liver than in adult liver. The major product with both fetal and adult mitochondria is betaine aldehyde. Choline oxidation by mitochondria begins to increase 1 day prior to birth and increases progressively to adult levels by 18 days. The developmental pattern for choline oxidation is similar to the pattern for succinic dehydrogenase activity.

Phospholipid metabolism in the developing liver: I. The biosynthesis of choline glycerophosphatides by liver slices from fetal, newborn and adult rats

1. 1. The biosynthesis of choline glycerophosphatides was evaluated in fetal, neonatal and adult female rat liver. The two main pathways were assessed by studying the rates of incorporation of [ Me- 14C]choline and [ Me- 14C]methionine by liver slices. 2. 2. Over 96% of the lipid radioactivity from [ Me- 14C] choline was located in choline glycerophosphatides. In adult liver slices 93% of the total lipid radioactivity from [ Me- 14C]methionine was located in choline glycerophosphatides. An appreciable amount of radioactivity from [ Me- 14C]methionine was incorporated into fatty acids by fetal liver slices. 3. 3. Liver slices from fetal rats incorporated the same amount of [ Me- 14C]choline into lecithin as did adult liver slices except for a drop 2 days before birth. Liver slices from 3-day-old neonatal rats incorporated about twice as much [ Me- 14C]choline as the adult liver slices. 4. 4. Liver slices from fetal and young rats incorporated about 8–10 times more [ Me- 14C]choline into phosphoryl choline than did liver slices from adults. Adult levels were reached at 10 days after birth. 5. 5. The incorporation of radioactivity from [ Me- 14C]methionine into lecithin by fetal liver slices was much lower than that by adult liver slices and increased to twice adult levels by 10–12 days after birth. Adult levels were reached by 25 days after birth. 6. 6. Studies with [1,2- 14C 2, Me- 14H]choline indicated that the choline was incorporated intact and that little, if any, of the methyl groups of choline were used for the methylation of phosphatidyl ethanolamine. 7. 7. The mechanism of choline incorporation into lecithin is discussed.