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In viral hepatitis, binding of Fas ligand (FasL) with Fas expressed on the surfaces of infected hepatocytes induces apoptosis, removing hepatitis virus along with infected hepatocytes. We measured serum concentrations of soluble Fas (sFas) and FasL (sFasL), expression of membrane-bound FasL, and expression of FasL-mRNA in patients with chronic hepatitis C without cirrhosis (CH-C) and chronic hepatitis C with liver cirrhosis (LC-C). In CH-C, sFasL concentrations were lower and FasL-mRNA expression was significantly less than in volunteers. In LC-C, sFas concentrations were significantly greater than in healthy volunteers, while sFasL, membrane-bound FasL expression, and FasL-mRNA expression did not show significant differences. We also examined these variables over 24 h following the first interferon (IFN) treatment in patients with CH-C. Serum concentrations of sFas and sFasL, and FasL-mRNA expression increased markedly beyond amounts present before IFN injection until 12 h after IFN injection. However, membrane-bound FasL expression decreased until 6 h, followed by an increase until 24 h. Our findings suggest that the ratio of membrane-bound FasL to sFasL may be regulated to remove virally infected cells in CH-C. In addition, apoptosis mediated by the Fas/FasL system may be influenced by IFN injection for treatment of CH-C.

We tested the effects of four bile acids, taurochenodeoxycholate, taurocholate, tauroursodeoxycholate and taurodeoxycholate, on kinesin-driven microtubule motility, which may have a major influence on membrane organelle transport in cholestasis. Reconstituted microtubules were incubated with kinesin purified from rabbit liver and brain. Binding and gliding of microtubules were visualized by video-enhanced differential interference contrast microscopy. Liver and brain kinesin produced similar microtubule gliding velocities. The effect of bile acids on liver and brain kinesin was also similar. Low concentrations of the four bile acids (0.25–0.5 mM) enhanced the speed of microtubule gliding by up to 152%. Higher concentrations of taurochenodeoxycholate and taurodeoxycholate inhibited attachment, but did not slow the speed of gliding. Detachment was inhibited by the addition of tauroursodeoxycholate. ATPase activity showed no changes in the presence of low concentrations of tauroursodeoxycholate and taurochenodeoxycholate. Triton X-100, a nonionic detergent, increased microtubule gliding by up to 147% at lower concentrations, while higher concentrations (up to 5%) caused a return to normal speed without detachment. Low concentrations of bile acids in hepatocytes may enhance kinesin-driven microtubule dependent organelle transport. In contrast, higher concentrations of toxic bile acids, chenodeoxycholate and deoxycholate, associated with cholestasis may inhibit kinesin-driven motility by detaching microtubules from kinesin.

Dibutyryl cyclic AMP (DBcAMP) is an analogue of cAMP. DBcAMP has many effects on hepatocellular carcinoma, liver cirrhosis, ischemic liver failure and endotoxin-induced inflammatory liver injury. However, little is known about the mechanism of DBcAMP action in Kupffer cells. We examined the effects of DBcAMP on phagocytic activity and production of nitric oxide (NO) and tumor necrosis factor- α (TNF- α ) in cultured rat Kupffer cells treated with lipopolysaccharide (LPS). NO concentrations in culture supernatants were measured using an NO analyzer and TNF- α levels were measured with ELISA. Immunofluorescent staining for nuclear factor- κ B (NF- κ B) was visualized using an anti-NF- κ B p65 antibody. DBcAMP premedication had no effect on LPS-stimulated phagocytic activity of Kupffer cells but increased NO production and inhibited TNF- α production in a dose-dependent manner. Genistein did not block, but H-89 did block, the inhibitory effect of DBcAMP on LPS-stimulated TNF- α production in Kupffer cells. We conclude that DBcAMP inhibits LPS-stimulated TNF- α production by activating cyclic AMP-dependent protein kinase. Using immunofluorescent staining for NF- κ B, we demonstrate that the effect of DBcAMP does not involve signal transduction through NF- κ B.

In ballooned hepatocytes associated with alcoholic liver disease, secretory proteins are abundant, possibly due to an impairment of the microtubule-dependent vesicular transport system. We studied the effects of ethanol and acetaldehyde on microtubules and hepatic kinesin function. Tubulin and microtubule-associated protein 2 was purified by phosphocellulose and hydroxyapatite column chromatography from microtubule proteins of bovine brain. Hepatic kinesin was purified from rabbit liver. The assembly of microtubules was quantified by spectro-photometer. The kinesin motility assay is done with or without various concentrations of ethanol or acetaldehyde using video-enhanced differential interference contrast microscopy. Ethanol had no effect on the assembly or disassembly of the microtubules or on hepatic kinesin function, even at high concentrations of up to 100 mM. In contrast, acetaldehyde reduced hepatic kinesin function at concentrations greater than or equal to 100 μ M and induced microtubular disassembly at concentrations greater than or equal to 200 μ M. In alcoholic liver injury, chronic reduction of hepatic kinesin function may cause retention of secretory proteins and hepatocyte swelling. Moreover, reduction of the microtubule concentrations due to acetaldehyde may further impair the vesicular transport system and reduce the cells ability to maintain morphology, in turn accelerating hepatocyte ballooning.

GB virus C (GBV-C) and hepatitis G virus (HGV) seemed to be the cause of hepatic injury in a setting of both acute and chronic infection. Some patients with hepatitis C virus (HCV) infection were coinfected with GBV-C/HGV. In the present study, we examined the effect of interferon on the GBV-C/HGV in chronic hepatitis C patients who were coinfected with GBV-C/HGV, in order to clarify the clinical significance of GBV-C/HGV infection. For GBV-C/HGV-RNA detection, the reverse transcription-nested polymerase chain reaction (RT-PCR) with primers from the 5′ untranslated subgenomic region was used. For GBV-C/HGV-RNA quantitative analysis, competitive RT-PCR was employed. Polymerase chain reaction products were directly sequenced. During IFN therapy, serum GBV-C/HGV-RNA became negative in nine patients (90%). However, a breakthrough of GBV-C/HGV was seen in two patients (20%), a virological relapse was seen after the cessation of IFN therapy in four patients (40%), and only three patients (30%) were sustained as negative. The changes in serum alanine aminotransferase levels after the cessation of IFN therapy correlated well with the changes in HCV-RNA. However, the correlation with GBV-C/HGV-RNA was poor. These results suggest that [1] GBV-C/HGV is sensitive to IFN therapy; and [2] In chronic hepatitis C patients coinfected with GBV-C/HGV and HCV, HCV appears to be involved with hepatocellular injury. It is less likely that GBV-C/HGV is directly involved in the initiation and progression of hepatic injury.

The efficacy of Interferon (IFN) therapy against hepatitis C is greatly affected by viral factors such as the level of viremia and the HCV genotype. The prognosis of those with high serum HCV-RNA levels in genotype 1b is poor. In the present report, we carried out a randomized controlled study of two IFN doses for patients with genotype 1b chronic hepatitis C whose serum HCV-RNA levels were at least 10 6 copies/ml as determined by multicyclic polymerase chain reaction (PCR) assay. These patients were randomly divided into two groups. Group A received 6 million units (MIU) of IFN 6 days per week for 8 weeks, followed by the same dose 3 days per week for 16 weeks (total IFN dose: 576 MIU). Group B received 6 MIU of IFN 6 days per week for 2 weeks, followed by the same dose 3 days per week for 22 weeks (total IFN dose: 480 MIU). The number of complete responders was four of 24 (16.6%) in group A and three of 20 (15.0%) in group B. There was no significant difference between the groups. On the basis of these findings, it appears that there is no advantage in lengthening the initial period of consecutive IFN administration to 8 weeks or in increasing the total dose by 100 MIU for those with genotype 1b hepatitis C and high virus levels.