Rho/Rho kinase is a key enzyme system involved in the angiotensin II signaling pathway of liver fibrosis and steatosis.

BACKGROUND AND AIM: The molecular mechanisms underlying the involvement of the renin-angiotensin system in hepatic fibrosis are unclear. Recently, it was reported that a Rho kinase inhibitor prevented fibrosis of various tissues and that the Rho/Rho kinase pathway was involved in the renin-angiotensin system of vascular smooth muscle cells. In this study, the involvement of the Rho/Rho kinase pathway on angiotensin II signaling in liver fibrogenesis and generation of steatosis was investigated. METHODS: Rats were fed a choline-deficient/L-amino acid-defined (CDAA) diet continuously and treated with a Rho kinase inhibitor, Y-27632, and an angiotensin II receptor blocker, TCV-116. Liver histology and hepatic stellate cell activation were analyzed. Free radical production was detected by 4-hydroxynonenal and 8-hydroxy-2'-deoxyguanosine immunostaining and the expression of tumor necrosis factor-alpha was examined. Isolated hepatic stellate cells were pretreated with a Rho kinase inhibitor, Y-27632, or an angiotensin II receptor blocker, CV-11974, and stimulated with angiotensin II, and mRNA expression of transforming growth factor-beta and alpha-smooth muscle actin was analyzed. RESULTS: Both the angiotensin II receptor blocker and the Rho kinase inhibitor improved fibrosis and steatosis of the liver in CDAA-fed rats. The increase in the number of hepatocytes positive for 4-hydroxynonenal and 8-hydroxy-2'-deoxyguanosine in CDAA-fed rats was significantly prevented by the angiotensin II receptor blocker and the Rho kinase inhibitor. The levels of tumor necrosis factor-alpha mRNA in the liver of CDAA-fed rats were significantly increased and this increase was significantly inhibited by treatment with the angiotensin II receptor blocker and the Rho kinase inhibitor. mRNA expression of transforming growth factor-beta and alpha-smooth muscle actin stimulated by angiotensin II was also significantly suppressed by these two drugs. CONCLUSION: These results suggest that the Rho/Rho kinase pathway is at least partly involved in the renin-angiotensin system and plays an important role in hepatic fibrosis and steatosis.

Effect of long-term interferon therapy for refractory chronic hepatitis c: preventive effect on hepatocarcinogenesis.

BACKGROUND/AIMS: Effect of interferon (IFN) therapy for refractory chronic hepatitis C is not sufficient. For patients with persistent hepatitis C virus (HCV) infection, one of the clinical goals is prevention of progression to liver cirrhosis (LC) and hepatocellular carcinoma (HCC). In this study, we evaluated effect of long-term IFN administration for refractory chronic hepatitis C. METHODOLOGY: The patients who were positive for HCV of genotype lb in high viral load and failed in HCV elimination by standard IFN therapy were retrospectively analyzed. The patients were divided into three groups according to administration duration of IFN therapy. The patients in group 1, 2 and 3 received IFN therapy for 6 months, 6-24 months and more than 24 months, respectively. RESULTS: The normalization rate of alanine aminotransferase (ALT) levels less than twice that of the normal limit 6 months after the treatment was highest in group 3 (85%). The platelet counts in group 1 gradually decreased more than 3 x 10(4)/microL from the pretreatment levels at 100 months after the start of treatment. Cumulative hepatocarcinogenesis rate in groups 1, 2 and 3 were 34.7%, 5.9% and 0%, respectively. We found distinct improvement in both ALT levels and histopathological findings in the case that received the longest term of IFN therapy (91 months). CONCLUSIONS: Long-term IFN therapy is effective in preventing hepatocarcinogenesis through reduction of chronic necroinflammation and accumulation of fibrosis in the liver and may be a good indication even for refractory chronic hepatitis C.

Contribution of Irf-1 promoter polymorphisms to the Th1-type cell response and interferon-beta monotherapy for chronic hepatitis C.

We recently reported promoter polymorphisms in the IRF-1 gene, an interferon-inducible gene that plays an important role in host antiviral function. The promoter activity was shown to be different between different polymorphisms. In this study, we investigated the relationship between IRF-1 promoter polymorphisms and the response to interferon monotherapy for chronic hepatitis C. Eighteen patients with a low initial viral load or hepatitis C virus (HCV) genotype non-1b received 6-months course of interferon-beta monotherapy. IRF-1 gene mutations and the treatment response were investigated. The IRF-1 promoter type possessing a higher promoter activity (-415C/-410A/-300A) was found in only three patients, all of which had a lower viral load than those with other promoter types and were able to obtain a sustained viral response. Flow cytometric analysis of peripheral blood mononuclear cells showed that the patients with a higher promoter activity of the IRF-1 had a significantly higher proportion of T helper 1-type CD4(+) cells after interferon administration than those of other promoter types. These results suggest that IRF-1 promoter polymorphisms may contribute, at least partially, to host antiviral activity for chronic hepatitis C.

Efficacy of non-invasive elastometry on staging of hepatic fibrosis.

To assess the efficacy of elastmetry in the determination of fibrotic stage in the liver, we investigated correlation between liver histology and the elastometry using a device equipped with a vibrator and an ultrasound system (Echosens, Paris, France) in patients with chronic hepatitis C. Totally 75 patients, 24 in F1 stage, 17 in F2 stage, 18 in F3 stage, and 16 in F4 stage according to the new Inuyama classification without fatty change were investigated. Correlations between the staging of liver fibrosis and elastometry, serum fibrosis makers and platelet counts were investigated. The elastometry was absolutely non-invasive. Serum fibrosis markers did not well correlate with the stage of liver fibrosis. Platelet counts significantly ( [Formula: see text] ) correlated with the fibrotic stage. Median platelet counts in each stage was; F1, 191.5; F2, 172.0; F3, 132.0; F4, 77.5 (x10(3)microl(-1)). However, the deviation was comparatively broad. On the contrary, the elastometry correlated well to the stage of fibrosis and the deviation was small. Median elastometric levels in each stage were; F1, 6.25; F2, 7.80; F3, 13.85; F4, 34.00 (kPa). These results suggest that elastometry is significantly useful for evaluating fibrotic staging of the liver without any invasiveness.

A free radical scavenger, edaravone, attenuates steatosis and cell death via reducing inflammatory cytokine production in rat acute liver injury.

BACKGROUND/AIMS: Reactive oxygen radicals play an important role in various forms of liver injury. In this study, we evaluated the efficacy of edaravone, a newly synthesized free radical scavenger, in its clinical dosage on an experimental model of acute liver injury in rats. METHODS: The clinical dose of edaravone (3 mg/kg) was intravenously administered immediately and 3 h after intraperitoneal administration of carbon tetrachloride (CCl4) in rats. Histological evaluation including apoptosis and cytokine profiles were examined. RESULTS: Fatty degeneration and necrosis with marked elevation of serum alanine aminotransferase and lactate dehydrogenase levels developed after CCl4 administration were significantly reduced by edaravone. In addition, the apoptotic index assessed by TUNEL method was significantly lowered in the edaravone treated group. Serum and liver transcription levels of interleukin-6, tumor necrosis factor-alpha, interleukin-4, and interleukin-10 were increased following CCl4 administration, and they were attenuated by edaravone treatment. The formation of malondialdehyde, 4-hydroxynonenal adduct and one of the markers for oxidative DNA damage, 8-hydroxy-2'-deoxyguanosine, was also inhibited by edaravone treatment. CONCLUSION: Edaravone has a remarkable protective effect on acute liver injury caused by oxygen radicals through not only attenuating the membrane lipid peroxidation, but also inhibiting the production of inflammatory cytokines. We theorize that edaravone may have a clinical benefit in the treatment of various liver injuries.

Genomic mutations with amino acid substitutions of circulating hepatitis B virus found in non-B, non-C patients with hepatocellular carcinoma.

OBJECTIVE: Most hepatocellular carcinoma (HCC) in Japan is caused by chronic infection with hepatitis B virus (HBV) or hepatitis C virus (HCV). HBV DNA has been detected in the serum and liver tissue of some proportion of those patients who are HBs antigen-negative and HCV antibody-negative; i.e., non-B, non-C (NBNC) patients with HCC. We sought to detect HBV DNA in the serum from NBNC HCC cases and to investigate genomic mutations of HBV in seronegative cases. PATIENTS AND METHODS: The sera from 26 NBNC HCC patients were examined by polymerase chain reaction (PCR) followed by southern blotting for existence of HBV DNA. The precore/core and polymerase regions of the HBV genome in the sera from five seronegative cases were analyzed by direct sequence. RESULTS: HBV DNA was detected in 17 of 26 patients (65.4%). Demographic factors such as age, gender, anti-HBs positivity, anti-HBc positivity, complication with cirrhosis, and excessive alcohol intake did not affect circulating HBV positivity. Genomic mutations with amino acid substitutions were detected in the polymerase and the precore regions from one of the five cases, and in the core region from four of the five cases. CONCLUSIONS: PCR-based HBV screening is necessary in patients suffering from liver diseases of unknown etiology, although its etiological importance and benefit of viral elimination have not been established. Genomic mutations in the precore/core and the polymerase region detected in this study might be involved in the lack of HBsAg in NBNC HCC cases.