Unveiling the roles of the glutathione redox system in vivo by analyzing genetically modified mice.

Redox status affects various cellular activities, such as proliferation, differentiation, and death. Recent studies suggest pivotal roles of reactive oxygen species not only in pathogenesis under oxidative insult but also in intracellular signal transduction. Glutathione is present in several millimolar concentrations in the cytoplasm and has multiple roles in the regulation of cellular homeostasis. Two enzymes, γ-glutamylcysteine synthetase and glutathione synthetase, constitute the de novo synthesis machinery, while glutathione reductase is involved in the recycling of oxidized glutathione. Multidrug resistant proteins and some other transporters are responsible for exporting oxidized glutathione, glutathione conjugates, and S-nitrosoglutathione. In addition to antioxidation, glutathione is more positively involved in cellular activity via its sulfhydryl moiety of a molecule. Animals in which genes responsible for glutathione metabolism are genetically modified can be used as beneficial and reliable models to elucidate roles of glutathione in vivo. This review article overviews recent progress in works related to genetically modified rodents and advances in the elucidation of glutathione-mediated reactions.

(99m)Tc-GSA SPECT analysis was clinically useful to evaluate the effect of interferon in a patient with interferon non-responsive chronic hepatitis C.

We describe a 62-year-old woman with advanced chronic hepatitis C who showed no response to low-dose long-term interferon-beta monotherapy (3 MU, three times a week). The interferon monotherapy was continued for 2 years and 9 months. Despite this lack of response to interferon, the patient's clinical course was good and liver function assessed by (99m)Tc-galactosyl human serum albumin single photon emission computed tomography ((99m)Tc-GSA SPECT) analysis improved significantly. Improvement of the data obtained by (99m)Tc-GSA SPECT analysis justified continuation of the treatment. (99m)Tc-GSA SPECT analysis was clinically useful to evaluate the effect of interferon in a patient with interferon non-responsive chronic hepatitis C, despite a lack of reduction of the ALT level and HCV-RNA titer.

Relationship between alcohol consumption and serum adiponectin levels: the Takahata study--a cross-sectional study of a healthy Japanese population.

CONTEXT: The relationship between alcohol consumption and serum adiponectin levels has not been fully explored in an Asian population. OBJECTIVE: Our goal was to determine whether alcohol consumption is associated with a change in adiponectin levels in a healthy Japanese population. DESIGN: This was a cross-sectional study. SETTING: Subjects were recruited from participants in a health check-up program. PARTICIPANTS: This study included 2932 subjects (1306 men and 1626 women). MAIN OUTCOME MEASURES: The effects of total weekly or daily volume of ethanol intake on serum adiponectin levels were evaluated. In addition, the correlation of clinical traits with serum adiponectin levels was examined. A multivariate regression model was used to control for possible confounding factors. RESULTS: Alcohol consumption was weakly correlated with decreased serum adiponectin levels in men [Spearman's ordered correlation coefficient (rs=-0.141; P<0.001]; an even weaker correlation was seen in women (rs=-0.055; P=0.025). Multivariate analysis demonstrated that alcohol consumption was independently associated with hypoadiponectinemia. CONCLUSION: In contrast to reports from the United States and Europe among White and Black subjects, our study demonstrated an inverse association between alcohol intake and serum adiponectin levels in Asian subjects, suggesting ethnic differences in the effects of alcohol consumption on serum adiponectin levels.

Impact of metabolic syndrome on elevated serum alanine aminotransferase levels in the Japanese population.

Measurement of the serum alanine aminotransferase (ALT) level is used as an initial test for detection of liver diseases, and recent studies have also highlighted its potential value as a measure of overall health and survival as a marker of an increased risk of metabolic disorder. This study was designed to clarify the prevalence of elevated ALT levels in the Japanese population and to assess factors associated with ALT elevation. The subjects were 2165 individuals aged 40 to 85 years who participated in a Japanese community-based study referred to as the Takahata Study. Serum ALT levels and factors associated with ALT elevation were investigated. Among 2087 subjects who were negative for hepatitis B and C, the rates of elevated ALT greater than 30 U/L in men and greater than 25 U/L in women were 217 (22.7%) of 957 and 239 (21.2%) of 1130, respectively. These ALT cutoff levels had a specificity of more than 80% for exclusion of subjects with none or 1 of 3 metabolic risk factors: hypertension, lipid metabolism abnormality, and hyperglycemia. Multivariate analysis revealed 5 factors with a significant association with ALT elevation in men (n = 957): high gamma-glutamyltranspeptidase, low adiponectin, high low-density lipoprotein cholesterol, high body mass index, and high homeostasis model assessment insulin resistance index. Similarly, 4 factors were significantly associated with ALT elevation in women (n = 1130): high gamma-glutamyltranspeptidase, low adiponectin, high body mass index, and high homeostasis model assessment insulin resistance index. These results suggest that elevated ALT levels in the Japanese population older than 40 years have a strong association with metabolic syndrome-related features including obesity and insulin resistance.

Down-regulation of hepatic stearoyl-CoA desaturase 1 expression by angiotensin II receptor blocker in the obese fa/fa Zucker rat: possible role in amelioration of insulin resistance and hepatic steatosis.

BACKGROUND: It has been reported that angiotensin II type 1 receptor blocker (ARB) can ameliorate hepatic steatosis and insulin resistance. Stearoyl-CoA desaturase 1 (SCD-1), which catalyzes the cellular synthesis of monounsaturated fatty acids, affects lipid metabolism. In this study, we investigated whether SCD-1 gene expression is affected by ARB treatment. METHODS: Obese fa/fa Zucker rats fed a high-fat diet were treated with a potent ARB and olmesartan, and the resulting changes in the components of serum and liver were studied. Gene expression of hepatic SCD-1 was assayed using real-time PCR. RESULTS: The serum glucose and insulin levels and hepatic TG content of the obese Zucker rats fed a high-fat diet were reduced after olmesartan administration, while the serum adiponectin level was increased. Real-time PCR revealed an increase of SCD-1 gene expression in the liver of these rats, followed by a reduction after olmesartan administration. The ratio of stearic acid (C18:0) to oleic acid (C18:1) in the liver was increased by olmesartan, indicating a reduction in the in vivo activity of SCD-1. CONCLUSIONS: ARB ameliorates hepatic steatosis and insulin resistance in obese fa/fa Zucker rats fed a high-fat diet. Gene expression of SCD-1 is decreased by olmesartan, suggesting that the beneficial effect is due partly to suppression of the key enzyme for hepatic lipid metabolism by ARB.

Risk of hepatocellular carcinoma and secondary structure of hepatitis C virus (HCV) NS3 protein amino-terminus, in patients infected with HCV subtype 1b.

We conducted a retrospective study of 65 patients with chronic hepatitis C, to determine whether the secondary structure of the amino-terminal 120 residues of the hepatitis C virus (HCV) NS3 protein is associated with an increased risk of development of hepatocellular carcinoma (HCC). The cumulative incidence of HCC was highest among patients infected with group B HCV-1b, wherein the risk of HCC significantly increased compared with that among patients infected with group A (hazard ratio, 4.95 [95% CI, 1.43-17.11]) after adjustment for age and histological stage. This HCV-1b grouping may be a useful marker for detecting the risk of development of HCC.

Serum levels of stem cell factor and thrombopoietin are markedly decreased in fulminant hepatic failure patients with a poor prognosis.

BACKGROUND AND AIM: Hematopoietic growth factors including stem cell factor (SCF), thrombopoietin (TPO) and granulocyte colony stimulating factor (G-CSF) have a potential role in inducing bone marrow hematopoietic stem cells to move into the circulation, and the association of these factors with liver regeneration has received a lot of attention recently. The aim of this study was to determine the serum levels of such factors in patients with acute liver injury. METHODS: The subjects were 25 patients with acute hepatitis (AH) who had a favorable prognosis and 26 patients with fulminant hepatitis (FH), of whom 11 were alive and 15 had died. Sixty-six healthy subjects matched for age and sex served as controls. Serum samples were collected before treatment, and the levels of SCF, TPO and G-CSF were measured using enzyme-linked immunosorbant assays. RESULTS: The levels of SCF and TPO were significantly lower in FH patients than in AH patients and the controls, and were also significantly lower in the FH patients who died, compared to the surviving patients. The G-CSF levels did not differ among them. CONCLUSIONS: These results suggest that low serum levels of SCF and TPO may be linked to poor prognosis in patients with severe liver injury.

Characteristics of rat bone marrow cells differentiated into a liver cell lineage and dynamics of the transplanted cells in the injured liver.

BACKGROUND: Bone marrow cells (BMCs) have been shown to differentiate into a liver cell lineage, but little is known about their dynamics following transplantation. BMCs were cultured to investigate the expression of liver-specific genes in vitro and transplanted into in vivo liver-injury models to elucidate their dynamics in the liver. METHODS: The mRNA expression of various liver-specific genes in BMCs cocultured with hepatocytes was analyzed using reverse transcription-polymerase chain reaction. BMCs from transgenic rats expressing green fiuorescent protein were transplanted into the spleen of rat liver-injury models induced with 2-acetylaminofiuorene (2-AAF) or carbon tetrachloride (CCl4). BMCs were also transplanted directly into livers treated with CCl4 to determine which route is better for transplantation. RESULTS: BMCs differentiated into a liver cell lineage in vitro and expressed mRNAs consistent with mature hepatocytes, including albumin. The transplanted BMCs were found in the liver in the CCl4-induced injury model, but not in the 2-AAF-induced model. The hepatocyte growth factor and fibroblast growth factor mRNA levels in the liver were significantly higher in the CCl4-induced model than in the 2-AAF-induced model. Migration of BMCs to the liver was more effective following injection into the liver, rather than into the spleen. CONCLUSIONS: Cultured BMCs differentiated into a liver cell lineage are a potential source for cell transplantation. Transplantation is successful in the severely injured liver with a high level of expression of mRNAs for growth factors. Injection of BMCs directly into the liver is the preferred route of administration.

Reduction of serum ghrelin concentration during interferon-alpha therapy in patients with chronic hepatitis C.

The efficacy of interferon (IFN) therapy for chronic hepatitis C is dependent on compliance. Anorexia is an important adverse effect in determining compliance. To clarify the mechanisms underlying anorexia, the level of ghrelin was determined during therapy. Fourteen patients with chronic hepatitis C received IFN-alpha2b with or without ribavirin (Rib+ or Rib- group; n=7 in each group) for 24 weeks. Serum ghrelin concentrations and body weight were determined before, 2 and 24 weeks after initiation of therapy. Serum ghrelin concentrations and body weight significantly decreased 2 weeks after initiation of therapy (P=0.0008 and 0.0062, respectively), and then returned to the level before therapy. The Deltaghrelin concentration correlated with Deltabody weight after 2 weeks (r=0.726, P=0.023). Percentage reduction of serum ghrelin was significantly higher in the Rib+ group than in the Rib- group (P=0.046). Percentage reduction in body weight tended to be higher in the Rib+ group (P=0.057). IFN-alpha2b therapy causes short-term reduction of serum ghrelin and body weight, and this may occur to a greater extent with combination therapy. Reduction of serum ghrelin might contribute partly to anorexia, leading to weight loss.

Differentiation of rat bone marrow cells cultured on artificial basement membrane containing extracellular matrix into a liver cell lineage.

BACKGROUND/AIMS: Bone marrow (BM) cells have been shown to be capable of differentiating into a liver cell lineage in vitro. However, their differentiation and proliferation is poor, and the cell characteristics are poorly understood. METHODS: We cultured rat BM cells on an artificial basement membrane containing extracellular matrix (ECM) with hepatocyte growth factor (HGF). The expression of mRNA for liver-specific genes was analyzed by reverse transcription PCR. The expression of albumin and Musashi-1 by cultured cells was analyzed using a fluorescence-activated cell sorter (FACS). The proportions of albumin-positive cells when culture was performed with different concentrations of HGF were analyzed by FACS. RESULTS: On culture day 21, polygonal cells proliferated and formed cell colonies. These cells expressed mRNA for all the liver-specific genes analyzed, and showed heterogeneous differentiation, some cells expressing albumin, others expressing Musashi-1. Albumin-positive differentiated cells were large and rich in intracellular structures, while Musashi-1-positive undifferentiated cells had the opposite characteristics. Culturing cells with higher concentrations of HGF induced an increased proportion of albumin-positive cells. CONCLUSIONS: The results suggest that cell culture on an ECM with a high concentration of HGF increases the extent to which BM cells differentiate into a liver cell lineage and proliferate in vitro.

Expression of Notch signalling markers in bone marrow cells that differentiate into a liver cell lineage in a rat transplant model.

Notch signalling pathway plays an important role in cell differentiation. To investigate the implications of Notch signalling in the differentiation of rat bone marrow (BM) cells into a liver cell lineage, we used cultured BM cells to examine the mRNA expression of Musashi-1, which positively regulates Notch signalling, and made a transplant model to examine the protein expression of Notch signalling markers. For the in vivo experiment, BM cells were collected from transgenic rats expressing green fluorescence protein (GFP) and transplanted into the spleens of recipient rats, in which liver damage had been induced with carbon tetrachloride. The expression of Notch receptor 1 (Notch-1), Jagged-1 and Musashi-1, in the transplanted GFP-positive BM cells was investigated by immunohistochemistry. The expression of the liver-specific proteins, alpha-fetoprotein and cytokeratin19 was also investigated. Musashi-1 mRNA became detectable in the BM cells on culture day 7 in vitro. After transplantation, GFP-positive BM cells were observed in the portal areas of the recipient's livers. Notch-1, Jagged-1, Musashi-1, alpha-fetoprotein and cytokeratin19 were all expressed in the transplanted BM cells. These results suggest that the Notch signalling pathway plays a role in the differentiation of BM cells into a liver cell lineage.

Transmission of hepatitis C virus quasispecies between human adults.

To elucidate how hepatitis C virus (HCV) with multiple variants (quasispecies) is transmitted and adapts to the host during infection, we compared nucleotide and deduced amino acid sequences from hypervariable region1 (HVR1) of the E2 gene of HCV between a donor and a recipient who developed hepatitis after a needlestick accident. Thirty clones from each subject were sequenced after PCR amplification, cloning, and purification of plasmid DNA from single colonies of transformed bacteria. Genetic analysis revealed that the recipient's viral sequences were much less diverse than the donor's. We found a single predominant HCV HVR1 clone of the recipient in 22/30 isolates with the same amino acid sequence, and mimic clones in 8/30 isolates with only one amino acid substitution. These were all absent in the donor, who had 21 highly diverse sequences. Phylogenetic analysis of virus E1/E2 gene sequences showed that the recipient's unique sequences were related to the population of variants from the donor, in whom one isolate had 96% similarity to the recipient's predominant amino acid sequence. These results suggest that a minor subset of the donor's HCV variants is selectively transmitted to the recipient, and that the selection determines the predominant variant in the new host.

Genetic variations in humans associated with differences in the course of hepatitis C.

The outcome of hepatitis C virus (HCV) infection varies among individuals, but the genetic factors involved remain unknown. We conducted a population-based association study in which 238 Japanese individuals positive for anti-HCV antibody were genotyped for 269 single nucleotide polymorphisms (SNPs) in 103 candidate genes that might influence the course of infection. Altogether, 50 SNPs in 32 genes were listed. Genetic polymorphisms in IL4, IL8RB, IL10RA, PRL, ADA, NFKB1, GRAP2, CABIN1, IFNAR2, IFI27, IFI41, TNFRSF1A, ALDOB, AP1B1, SULT2B1, EGF, EGFR, TGFB1, LTBP2, and CD4 were associated with persistent viremia (P < 0.05), whereas those in IL1B, IL1RL1, IL2RB, IL12RB1, IL18R1, STAT5A, GRAP2, CABIN1, IFNAR1, Mx1, BMP8, FGL1, LTBP2, CD34, and CD80 were associated with different serum alanine aminotransferase levels in HCV carriers (P < 0.05). The sorted genes allow us to draw novel hypotheses for future studies of HCV infection to ultimately identify bona fide genes and their variations.

Possible contribution of circulating interleukin-10 (IL-10) to anti-tumor immunity and prognosis in patients with unresectable hepatocellular carcinoma.

OBJECTIVES: Interleukin-10 (IL-10) has been implicated in immune deficiency in patients with cancer. The relationship of this cytokine as measured in serum to anti-tumor immunity and prognosis was investigated in unresectable hepatocellular carcinoma. METHODS: This study consisted of 74 consecutive patients with unresectable hepatocellular carcinoma (median age, 65 years). Forty-four healthy age-matched subjects and 32 patients with cirrhosis but no carcinoma served as controls. Patients with hepatocellular carcinoma were divided into those with serum IL-10 concentrations above (high group, n=39) or below (low group, n=35) 10pg/ml. RESULTS: Age, gender, Child-Pugh grade, and tumor stage distributions were similar in high and low groups. The patients of high group showed lower in lymphokine-activated killer (LAK) and natural killer (NK) activities than those of low group (P<0.01 and 0.01, respectively). Serum IL-10 concentration was a significant factor contributing to low activities of LAK and NK by logistic regression analysis (P<0.05 and 0.05, respectively). The high group had a significantly shorter survival (median, 3 months) than low group (median, 12 months; P<0.02, generalized Wilcoxon test). CONCLUSIONS: These data suggest that serum IL-10 concentration is a possible factor contributing to poor prognosis and low anti-tumor immunity in patients with unresectable hepatocellular carcinoma.

Spontaneous elimination of serum hepatitis C virus (HCV) RNA in chronic HCV carriers: a population-based cohort study.

The natural course of hepatitis C virus (HCV) infection has not been fully elucidated. To investigate whether HCV is spontaneously eliminated in chronic carriers, a long-term population-based cohort study was conducted on 435 chronic HCV carriers. Individual characteristics, serum HCV RNA, and liver function tests were analyzed, and ultra sonography (US) was performed in all subjects. Subjects were followed up for 7.2 +/- 2.4 years (mean +/- SD). Serum HCV RNA was spontaneously eliminated in 16/435 (3.7%) individuals during this period; thus, the incidence of spontaneous elimination of serum HCV RNA was 0.5%/year/person. Multivariate analysis revealed that both a low value of ZTT and no US finding of chronic liver disease were associated with spontaneous viral elimination in HCV carriers. Three of these 16 individuals had chronic hepatitis, and 13 of them had normal ALT levels. When the neutralization of binding (NOB) assay that evaluates inhibition of the HCV envelope-2 protein binding to human cells was examined using sera from these 16 individuals, the NOB antibody was detected in only 3 cases with chronic hepatitis. These results suggest that serum HCV RNA is spontaneously eliminated in chronic HCV carriers in a population, and that the development of NOB antibody is associated with a natural resolution of chronic hepatitis in the minority of them.

Differentiation of bone marrow cells into cells that express liver-specific genes in vitro: implication of the Notch signals in differentiation.

Bone marrow (BM) stem cells have been shown to differentiate into liver cells. It remains difficult to sort and culture BM stem cells, and the gene expression of liver-specific proteins in these cells has not been fully investigated. We used a negative selective magnetic cell separation system to obtain stem cell-enriched BM cells. The cells obtained were cultured with hepatocytes or with hepatocyte growth factor (HGF), and the differentiation of BM cells into cells expressing liver-specific genes, hepatocyte nuclear factor (HNF) 1alpha, cytokeratin (CK) 8, alpha-fetoprotein (AFP), and albumin was investigated by the reverse transcription-polymerase chain reaction. We also investigated the gene expressions of Notch receptor-1 (Notch-1) and its ligand Jagged-1 in BM cell differentiation. Sorted BM cells showed positive for Sca-1 (Ataxin-1) by immunofluorescence staining. Fluorescence activated cell sorter analysis showed that 32.6% of sorted BM cells had a high level of expression of the hematopoietic stem cell marker CD90 (Thy-1). When cultured with hepatocytes, these cells expressed the liver-specific genes HNF1alpha and CK8 on culture day 3, AFP and albumin on culture day 7. When cultured with HGF (20ng/ml), the cells expressed HNF1alpha on day 3 and CK8 on day 7. Gene expressions of Notch-1 and Jagged-1 were detected in cultured BM cells on day 3. These results suggest that the negative selective magnetic cell separation system is useful for the rapid preparation of stem cell-enriched BM cells, and that the Notch signaling pathway plays a role in BM cell differentiation into a hepatocyte lineage in vitro.