Interaction of alcohol and hepatitis viral proteins: implication in synergistic effect of alcohol drinking and viral hepatitis on liver injury

Effects of alcohol consumption on viral hepatitis B and C

The liver is the main target organ for hepatitis viruses and the vital organ for alcohol metabolism. These two factors of viral hepatitis and alcohol abuse in combination can exert dual harmful actions, leading to enhanced damage to the liver. Epidemiological studies have revealed a higher prevalence of hepatitis C virus (HCV) infection among alcoholics than the general population. The interaction of alcohol with viral hepatitis [e.g., hepatitis B virus (HBV), HCV] and the underlying mechanisms are not fully understood. The effects of alcohol on viral hepatitis include promoted viral replication, weakened immune response, and increased oxidative stress. Clinically, alcohol abuse is correlated with an increased risk of developing end-stage liver cirrhosis and hepatocellular carcinoma in patients with chronic hepatitis B and C, suggesting that the combination of alcohol and HBV/HCV lead to more severe liver damage. The influence of mild to moderate alcohol drinking on the HBV-induced liver fibrosis, cirrhosis, and hepatocellular carcinoma among patients infected with HBV remains unclear. Unlike HBV infected patients, no safe level of alcohol intake has been established for patients with HCV. Even light to moderate alcohol use can exert a synergistic effect with viral hepatitis, leading to the rapid progression of liver disease. Furthermore, interferon-based therapy is less effective in alcohol drinkers than in control patients, even after abstinence from alcohol for a period of time. Therefore, abstaining from alcohol is highly recommended to protect the liver, especially in individuals with HBV/HCV infection, to improve the clinical efficacy of antiviral treatment and prevent the rapid progression of chronic viral hepatitis.

p53 Mutation at Serine 249 and Its Gain of Function Are Highly Related to Hepatocellular Carcinoma after Smoking Exposure

BACKGROUND

It has been convincingly suggested that a close correlation exists between the incidence of hepatocellular carcinoma (HCC) and cigarette smoking. However, the underlying effect of smoking on HCC is not clear.

METHODS

A binary unconditional logistic regression was used for the data on a total of 300 cases and 612 controls. The approach of functional analysis of separated alleles in yeast and direct sequencing of TP53 mutations were applied to analyze the p53 status in the HCC group. The relationship between p53 mutation at serine 249 (p53-RS) and smoking was assessed. Quantitative reverse transcription PCR was employed for the evaluation to transcriptional activity of p53 and p53-RS.

RESULTS

Smoking was linked to the risk of HCC with an increased dose-response effect. Moreover, among subjects who did not drink, the risks of HCC were significantly increased for smokers between HCC and controls. Besides, there was an increase in the number of HCC in smokers compared to nonsmokers after exclusion of HBV and/or HCV infection. Also, a significant difference was observed in the incidence of p53-RS between smokers and nonsmokers the HCC group. Furthermore, the p53-RS transcriptional activity was significantly increased in tumor tissues.

CONCLUSIONS

It strongly demonstrated that tobacco smoking is positively and independently associated with HCC, which may be attributed to p53-RS and its gain of function.

Chronic ethanol consumption and HBV induce abnormal lipid metabolism through HBx/SWELL1/arachidonic acid signaling and activate Tregs in HBV-Tg mice

Rationale: Chronic ethanol consumption as a public health problem worldwide boosts the development of chronic liver diseases in hepatitis B virus (HBV)-infected patients. Arachidonic acid metabolite prostaglandin E2 (PGE2) activates regulatory T cells (Tregs) function. Here, we aim to investigate the underlying mechanism by which chronic ethanol consumption enriches the HBV-induced abnormal lipid metabolism and Tregs.

Methods: The si-RNAs were used to weaken the expression of SWELL1 in HepG2, HepG2.2.15 and K180 cancer cell lines, followed by RNA sequencing from HepG2 cells. Arachidonic acid metabolite PGE2 and LTD4 were measured by ELISA assay in vivo and in vitro. Western blot analysis and RT-qPCR were used to examine HBx and SWELL1 and transcriptional factor Sp1 in clinical HCC samples and cell lines. The effect of chronic ethanol consumption on Tregs was tested by flow cytometry in HBV-Tg mice. The splenic Tregs were collected and analyzed by RNA sequencing.

Results: The cooperative effect of ethanol and HBV in abnormal lipid metabolism was observed in vivo and in vitro. The depression of SWELL1 (or HBx) resulted in the reduction of lipid content and arachidonic acid metabolite, correlating with suppression of relative gene atlas. Ethanol and SWELL1 elevated the levels of PGE2 or LTD4 in the liver of mice and cell lines. Interestingly, the ethanol modulated abnormal lipid metabolism through activating HBx/Sp1/SWELL1/arachidonic acid signaling. Chronic ethanol consumption remarkably increased the population of PBL Tregs and splenic Tregs in HBV-Tg mice, consistently with the enhanced expression of PD-L1 in vivo and in vitro. Mechanically, RNA-seq data showed that multiple genes were altered in the transcriptomic atlas of Tregs sorting from ethanol-fed mice or HBV-Tg mice.

Conclusion: The chronic ethanol intake enriches the HBV-enhanced abnormal lipid metabolism through HBx/SWELL1/arachidonic acid signaling and activates Tregs in mice.

IFN-α2b inhibits the ethanol enriched-HBV cccDNA through blocking a positive feedback loop of HBx/MSL2/cccDNA/HBV/HBx in liver

Hepatitis B virus (HBV) is a major risk factor for liver diseases, in which HBV covalently closed circular DNA (cccDNA), as the genomic form that templates viral transcription, plays crucial roles in sustaining viral persistence. Clinically, the excessive ethanol intake accelerates the progression of liver diseases with HBV infection. Here, we supposed that ethanol might trigger HBV cccDNA in the liver. Interestingly, we observed that the ethanol remarkably elevated the levels of HBeAg, HBsAg, HBV DNA and cccDNA in HBV-expressing hepatoma cells. Mechanically, the ethanol increased the levels of HBx and MSL2 in vivo and in HBV-expressing HepG2 cells, but not in HBV-free HepG2 cells. Moreover, the down-regulation of MSL2 by small interference RNA could block the ethanol-promoted HBV cccDNA in HepG2.2.15 cells. As a commonly administered treatment for HBV, the effect of IFNα on ethanol-triggered HBV cccDNA remains poorly understood. Strikingly, we showed that the treatment with IFN-α2b inhibited the ethanol-promoted cccDNA through depressing MSL2 in the cells. Thus, we conclude that IFN-α2b inhibits the ethanol-enriched HBV cccDNA through blocking a positive feedback loop of HBx/MSL2/cccDNA/HBV/HBx. Our finding provides new insights into the mechanism by which IFN-α2b inhibits ethanol-enhanced HBV cccDNA. Therapeutically, IFNα may contribute to the cccDNA induced by ethanol in liver.

Expression quantitative trait loci for TNFRSF10 influence both HBV infection and hepatocellular carcinoma development

Tumor necrosis factor receptor superfamily member 10 (TNFRSF10) is a death domain-containing receptor for the apoptotic ligand TNFSF10, which involves multiple processes, including hepatocarcinogenesis and immune response against HBV infection. Several single nucleotide polymorphisms (SNPs) were identified as expression quantitative trait loci (eQTLs) for TNFRSF10. To assess the association of TNFRSF10 eQTL SNPs with the risk of hepatocellular carcinoma (HCC) and chronic HBV infection, we designed a case-control study that included 1,300 HBV-related HCC patients, 1,344 chronic HBV carriers, and 1,344 subjects with HBV natural clearance, and then genotyped two TNFRSF10 eQTL SNPs (rs79037040 and rs2055822). We found that rs79037040 GT/TT genotypes were associated with a decreased HCC risk (adjusted odds ratio [OR] = 0.83, 95% confidence intervals [CIs] = 0.71-0.97, P = 0.021) but an increased chronic HBV infection risk of borderline significance (adjusted OR = 1.14, 95%CIs = 0.98-1.33, P = 0.085). In contrast, the rs2055822 G allele was a risk factor for HCC (adjusted OR = 1.12, 95%CIs = 1.00-1.25, P = 0.041) but a protective factor for chronic HBV infection (adjusted OR = 0.89, 95%CIs = 0.80-0.99, P = 0.038). Furthermore, we observed a dose-dependent relationship between the number of alleles (rs79037040-T and rs2055822-A) and the risk of HCC and chronic HBV infection. In comparison with "0" alleles, having "1-4" alleles was significantly associated with decreased HCC risk and increased HBV infection risk. These findings suggest that eQTL SNPs for TNFRSF10 may be susceptibility markers for HCC and chronic HBV infection.

Fifteen-year population attributable fractions and causal pies of risk factors for newly developed hepatocellular carcinomas in 11,801 men in Taiwan

Development of hepatocellular carcinoma (HCC) is a multi-factorial process. Chronic infections with hepatitis B virus (HBV) and hepatitis C virus (HCV) are important risk factors of HCC. Host factors, such as alcohol drinking, may also play a role. This study aims to provide a synthesis view on the development of HCC by examining multiple risk factors jointly and collectively. Causal-pie modeling technique was applied to analyze a cohort of 11,801 male residents (followed up for 15 years) in Taiwan, during which a total of 298 incident HCC cases were ascertained. The rate ratios adjusted by age were further modeled by an additive Poisson regression. Population attributable fractions (PAFs) and causal-pie weights (CPWs) were calculated. A PAF indicates the magnitude of case-load reduction under a particular intervention scenario, whereas a CPW for a particular class of causal pies represents the proportion of HCC cases attributable to that class. Using PAF we observed a chance to reduce around 60% HCC risk moving from no HBV-related intervention to the total elimination of the virus. An additional ∼15% (or ∼5%) reduction can be expected, if the HBV-related intervention is coupled with an HCV-related intervention (or an anti-drinking campaign). Eight classes of causal pies were found to be significant, including four dose-response classes of HBV (total CPW=52.7%), one independent-effect class of HCV (CPW=14.4%), one HBV-alcohol interaction class (CPW=4.2%), one HBV-HCV interaction class (CPW=1.7%), and one all-unknown class (CPW=27.0%). Causal-pie modeling for HCC helps clarify the relative importance of each viral and host factor, as well as their interactions.

Factors influencing the severity of acute viral hepatitis A

Background/Aims

Most patients with acute viral hepatitis A have a favorable course, but a few of them suffer from severe forms of hepatitis such as fulminant hepatitis. This study was carried out to identify the factors influencing the severity of acute viral hepatitis A.

Methods

We retrospectively reviewed the medical records of 713 patients with acute hepatitis A, who were divided into two groups: severe hepatitis A (N=87) and non-severe hepatitis A (N=626). Severe hepatitis was defined as fulminant hepatitis or prolongation of prothrombin time (INR≥1.5). Clinical variables were compared between the two groups.

Results

The incidence of fulminant hepatitis was 1.4% (10/713) in patients with acute hepatitis A. Thirty-three (4.6%) cases exhibited HBsAg positivity. In multivariate analyses, significant alcohol intake and the presence of HBsAg were significant predictive factors of fulminant hepatitis A, and significant alcohol intake and age were significant predictive factors of severe hepatitis A. HBeAg and HBV-DNA status did not affect the clinical course of hepatitis A in chronic hepatitis B carriers.

Conclusions

While most patients with acute hepatitis A have an uncomplicated clinical course, our data suggest that a more-severe clinical course is correlated with being older, significant alcohol intake, and chronic hepatitis-B-virus infection.

Alcohol consumption among patients with hepatitis B infection in northern Portugal considering gender and hepatitis B virus genotype differences

Alcohol abuse is an important public health problem. In Portugal with a population of 10 millions of inhabitants, there are around 10% of alcoholics or excessive alcohol drinkers and 1% of chronically infected patients with hepatitis B virus (HBV). To examine the characteristics of patients with higher levels of alcohol consumption and to investigate the association between alcohol consumption and liver damage a total of 298 chronically infected individuals, with HBV genotyped and submitted to liver biopsy, were classified with Child's grading and separated by habits of alcohol intake, less and greater than 20g/day. No significant differences were observed about genotype but genotypes A and D were predominant in both of them. A higher percentage of males (P<.001) were observed in the group with alcohol intake above 20g/day, as well a lower proportion of patients with HBeAg negativity (P< or =.035). In this group, biochemistry parameters, such as alanine aminotransferase (P=.006), aspartate aminotransferase (P=.001), gamma-glutamyl transferase (P<.001) were elevated in a significantly higher proportion than in the other group. The analysis of hematological parameters showed significantly lower values of platelets (P=.042) and mean corpuscular volume (P<.001) and significantly higher values of prothrombin time (P<.001) in the group with higher levels of alcohol consumption. The characteristics of biopsy (P<.001) and Child-Phug's classification (P=.002) revealed more severe results in this group. Logistic regression showed a positive association between liver damage and alcohol intake, increasing with age. In female patients, a strong positive association between alcohol intake and liver damage was also found (odds ratio: 9.379; 95% confidence interval: 0.859-468.422; P = .037); however, the most severe cases were only observed in women older than 45 years. In patients with HBV infection, alcohol is associated with a more severe liver disease. No evidence was found concerning association with HBV genotype.

Inflammation and repair in viral hepatitis C

Hepatitis C viral infection (HCV) results in liver damage leading to inflammation and fibrosis of the liver and increasing rates of hepatic decompensation and hepatocellular carcinoma (HCC). However, the host's immune response and viral determinants of liver disease progression are poorly understood. This review will address the determinants of liver injury in chronic HCV infection and the risk factors leading to rapid disease progression. We aim to better understand the factors that distinguish a relatively benign course of HCV from one with progression to cirrhosis. We will accomplish this task by discussion of three topics: (1) the role of cytokines in the adaptive immune response against the HCV infection; (2) the progression of fibrosis; and (3) the risk factors of co-morbidity with alcohol and human immunodeficiency virus (HIV) in HCV-infected individuals. Despite recent improvements in treating HCV infection using pegylated interferon alpha (PEGIFN-alpha) and ribavirin, about half of individuals infected with some genotypes, for example genotypes 1 and 4, will not respond to treatment or cannot be treated because of contraindications. This review will also aim to describe the importance of IFN-alpha-based therapies in HCV infection, ways of monitoring them, and associated complications.

Weil's disease in a patient with chronic viral hepatitis and history of alcohol abuse

Clinical and laboratory diagnosis of severe leptospirosis (Weil's disease) may be difficult when other pathological processes that may cause similar clinical syndromes or affect immune response to infections coexist. In addition, the optimal management of the disease remains to be defined. We report on a case of Weil's disease, in which concurrent chronic hepatitis B virus infection and alcohol abuse caused diagnostic and therapeutic difficulties.

Role of STAT3 in liver regeneration: survival, DNA synthesis, inflammatory reaction and liver mass recovery

The hepatoprotective effect of interleukin-6 (IL-6)/signal transducer and activator of transcription 3 (STAT3) has been well documented. However, reports on the role of IL-6/STAT3 in liver regeneration are conflicting probably due to the fact that the model of Stat3 knockout mice were complicated with obesity and fatty liver, which may cause some secondary effects on liver regeneration. To study the direct role of STAT3 and to circumvent the problems of obesity and fatty liver in liver regeneration, we generated conditional STAT3 knockout in the liver (L-Stat3(-/-)) using a transthyretin-driven Cre-lox method. The L-Stat3(-/-) mice were born with the expected Mendelian frequency and showed no obesity or other obvious phenotype. After partial hepatectomy, mortality in the L-Stat3(-/-) mice was significantly higher than the littermate Stat3(f/+) controls in the early time points (<24 h). Hepatocyte DNA synthesis in the survived L-Stat3(-/-) mice slightly decreased as compared with Stat3(f/+) mice at 40 h after partial hepatectomy, whereas similar hepatocyte DNA synthesis was found at other time points and liver mass could be completely recovered in the L-Stat3(-/-) mice. In another model of liver regeneration induced by subcutaneous injection of carbon tetrachloride (CCl(4)), hepatocyte DNA synthesis in the CCl(4)-treated L-Stat3(-/-) mice also decreased as compared with Stat3(f/+) mice at 40 h after injection but not at other time points. In addition, infiltration of neutrophils and monocyte increased in the liver of CCl(4)-treated L-Stat3(-/-) mice compared to wild-type mice. In conclusion, STAT3 is required for survival in the acute stage after 70% hepatectomy and plays a role in inflammatory reaction after hepatocyte necrosis. However, the hepatocytic STAT3 may have limited role in liver mass recovery although DNA synthesis may be impaired.

Additive effect of ethanol and HCV subgenomic replicon expression on COX-2 protein levels and activity

The mechanisms by which alcohol exacerbates liver injury in patients with hepatitis C are unknown. We used the hepatitis C virus (HCV) subgenomic replicon cell system to evaluate the effect of ethanol on HCV replication and viral protein synthesis. Our results demonstrate that alcohol stimulates HCV replicon expression at both HCV-RNA and protein levels. Furthermore, we observed that ethanol treatment showed an additive effect in cyclooxygenase-2 (COX-2) protein expression and activity already induced by HCV viral proteins, and in turn increased HCV viral expression. Our results suggest that COX-2 activity is involved in ethanol-induced HCV-RNA and NS5A protein expression, because acetylsalicylic acid (ASA), a COX-1/2 inhibitor, blocked this induction and downregulated COX-2 protein expression and activity. Therefore, we suggest that ethanol increases HCV replication expression, at least in part, by upregulating a key cellular regulator of oxidative stress pathway known as COX-2 or its products.

Role of the proteasome in ethanol-induced liver pathology

The ubiquitin-proteasome system has come to be known as a vital constituent of mammalian cells. The proteasome is a large nonlysosomal enzyme that acts in concert with an 8.5 kDa polypeptide called ubiquitin and a series of conjugating enzymes, known as E1, E2 and E3, that covalently bind multiple ubiquitin moieties in a polyubiquitin chain to protein substrates in a process called ubiquitylation. The latter process targets protein substrates for unfolding and degradation by the 26S proteasome. This enzyme system specifically recognizes and degrades polyubiquitylated proteins, many of which are key proteins involved in cell cycle regulation, apoptosis, signal transduction, and antigen presentation. The 26S proteasome contains a cylinder-shaped 20S catalytic core that, itself, degrades proteins in an ATP- and ubiquitin-independent manner. The 20S form is actually the predominant enzyme form in mammalian cells. Proteolysis by the constitutive 20S proteasome is vital in removing oxidized, misfolded and otherwise modified proteins. Such degradation is critical as a means of cellular detoxification, as intracellular accumulation of damaged and misfolded proteins is potentially lethal. Studies have shown that inhibition of proteasome activity can lead to cell death. Ethanol and its metabolism cause partial inhibition of the proteasome. This leads to a number of pleiotropic effects that can affect a variety of cellular processes. This critical review describes important aspects of ethanol metabolism and its influence on the proteasome. The review will summarize recent findings on: (1) the interactions between the proteasome and the ethanol metabolizing enzyme, CYP2E1; (2) the dynamics of proteasome inhibition by ethanol in animal models and cultured cells; (3) ethanol-elicited suppression of proteasome activity and its effect on signal transduction; (4) The role of proteasome inhibition in cytokine production by liver cells; and (5) ethanol elicited suppression of peptide hydrolysis and the potential effects on antigen presentation. While the principal focus is on alcohol-induced liver injury, the authors foresee that the findings presented in this review will prompt further research on the role of this proteolytic system in other tissues injured by excessive alcohol consumption.

Alcohol and hepatitis C mortality among males and females in the United States: a life table analysis

OBJECTIVE

Evidence from previous studies suggests that heavy alcohol use (HAU) exacerbates the rate of fibrosis progression in the liver and results in increased probability for premature death among patients with hepatitis C virus (HCV) infection. The current study uses population-based mortality data to investigate whether heavy drinking affects the age of death among individuals with HCV and, if so, whether this effect differs between men and women.

METHODS

A total of 7,263,163 death records in the United States between 2000 and 2002 were drawn from the Multiple Cause of Death (MCD) public-use data files compiled by the National Center for Health Statistics (NCHS). International Classification of Diseases, Tenth Revision (ICD-10) codes were used to identify the presence of HCV (B17.1 and B18.2) and HAU (as indicated by alcohol-induced medical conditions, F10 and K70) either as the underlying cause or as one of the contributing causes of death. The deaths were divided into 4 distinctive cause-of-death categories: HCV without HAU, HAU without HCV, HCV plus HAU, and all others. The mean ages of death and the cumulative probabilities of death derived from multiple-cause life table were compared across these categories.

RESULTS

Hepatitis C virus deaths showed an excessive prevalence of HAU when compared with non-HCV deaths. Compared with deaths of HCV without HAU, the mean age of death was shortened for deaths of HCV plus HAU (from 55.1 to 50.0 years among males, and from 61.0 to 49.1 years among females). The cumulative probability of death before age 65 was much higher for the latter than the former group (0.91 vs 0.68 among males, and 0.88 vs 0.47 among females). While HCV alone showed a disproportionate effect on premature death in males, HAU presented a stronger effect in females, resulting in a "catching-up" effect that diminished the gender difference in age of HCV death.

CONCLUSIONS

This study provides mortality-based evidence to further establish heavy alcohol consumption as one of the key risk factors contributing to premature deaths from HCV in the United States. More importantly, this study, for the first time, presents empirical evidence that alcohol consumption affects men and women differently in HCV mortality.

Referrals for surgical therapy in patients with hepatocellular carcinoma: a community experience

The treatment of hepatocellular carcinoma (HCC) is notoriously difficult. Either because of oncogenic behavior or the frequent association of cirrhosis, successful therapy is elusive, particularly in cirrhotic patients. Surgical removal has been the only modality that has produced long-term, disease-free survival. In a large series of patients from specialty institutions, median survival in those who underwent resection of HCC lesions has ranged from 30 to 70 months. Similarly, liver transplantation has been shown to be an effective treatment when HCC is favorable (limited in size and number), producing long-term survival in greater than 70% of patients. However, less information is known about community-based treatment of HCC. Reports from referral centers may not accurately reflect the community experience. We have retrospectively reviewed patients with HCC seen in surgical referral from three teaching hospitals in a medium-size urban community from 1995 to 2004 who were not felt to be candidates for liver transplantation and who were not sent to referral centers. We sought to examine their suitability for operation and resection. The study group comprised 61 patients, whose ages ranged from 35 to 83 years old. There were 44 patients (72%) with cirrhosis (Childs A, B, and C in 27, 15, and 2 patients, respectively), 21 from hepatitic C virus (HCV) infection. Three recognized staging systems were used that incorporated the estimation of hepatic reserve and tumor burden. Seven patients (11%) were deemed nonoperable (five advanced disease by imaging, two comorbidities). Of the 54 patients who underwent surgical procedures, 32 underwent resection (28 patients) or cryoablation (4 patients). The reasons for unresectability were unrecognized multifocality (ten patients), poor risk for major hepatectomy (five patients), portal vein/hepatic vein involvement (three patients), metastatic disease (two patients), and excessive blood loss prior to hepatectomy (two patients). Eleven of 17 (65%) noncirrhotic patients and 21 of 44 (48%) cirrhotic patients were resectable or ablatable. There were ten postoperative deaths: six following resection, two following cryoablation, and two following exploratory celiotomy. All deaths were in cirrhotic patients (Childs A in four patients, B in five patients, and C in one patient), 10 of 44 patients (23%); 3 of 11 (27%) patients died following segmentectomy and 3 of 9 (33%) following major hepatectomy. Seven deaths that occurred were in patients with HCV; (P = NS). From this series, the difficulty in surgically treating cirrhotic patients in an urban practice is evident. From 39 to 73% of patients had advanced local disease. Less than half were resectable and, for cirrhotic patients, the postoperative mortality was high, even after "minor" hepatectomies. Noncirrhotic patients fared somewhat better. While HCC in community practice can be treated surgically in the majority of noncirrhotic patients, cirrhotic patients are less likely candidates, and surgical treatment is associated with significant postoperative mortality. This frequently reflected advanced disease and HCV but may be associated with access to preventative and surveillance measures. Only those with optimum hepatic reserve and small tumor burden should be considered for surgical resection.

Ethanol-induced oxidative stress suppresses generation of peptides for antigen presentation by hepatoma cells

Processing of peptides for antigen presentation is catalyzed by antigen-trimming enzymes, including the proteasome and leucine aminopeptidase. Oxidative stress suppresses proteasome function. We hypothesized that in liver cells, processing of antigenic peptides is altered by ethanol metabolism. To address this issue, soluble extracts of ethanol-metabolizing VL-17A cells treated with 100 mM ethanol or left untreated were incubated with C-extended or N-extended 18-27 HBV core peptides. Peptide cleavage was measured by recovery after HPLC. Ethanol exposure to VL-17A cells increased CYP2E1 and decreased proteasome peptidase activities. The latter effect was prevented by treatment of cells with inhibitors, 4-methylpyrazole and diallyl sulfide. Ethanol treatment of VL-17A cells also reduced the activity of leucine aminopeptidase (LAP). Consequently, cleavage of both C-extended and N-extended peptides by cytosolic extracts was suppressed by pretreatment of cells with ethanol. Treatment of cells with interferon gamma, which enhances proteasome activity, did not reverse the effects of ethanol. Ethanol exerted similar effects on WIFB cells, indicating that its effects are not unique to one cell type.

CONCLUSION

Ethanol metabolism suppresses activities of antigen-trimming enzymes, thereby decreasing the cleavage of C-extended and N-extended peptides. This defect may potentially result in decreased MHC class I-restricted antigen presentation on virally infected liver cells.

Analysis of HLA-DQB1 gene polymorphisms in asymptomatic HBV carriers and chronic hepatitis B patients in the Chinese Han population

Host genetic factors and environment factors including hepatitis B virus (HBV) genotype are widely viewed as common basis of the different outcomes of HBV infection. Human leucocyte antigen (HLA) plays an important role in immunological reaction to HBV infection. The study aimed to explore whether the HLA-DQB1 allele polymorphisms are associated with the outcomes of HBV infection in the Chinese Han population. One hundred and thirty-four asymptomatic HBV carriers and 139 chronic hepatitis B patients were recruited in this case-control study in Beijing, China. Sequence-specific primers-polymerase chain reaction was used to detect 13 alleles of HLA-DQB1 gene. The frequency distributions of alleles in two groups were analysed using sas 9.1.2 software. After adjustment of confounders the frequencies of HLA-DQB1*0503 allele and *0303 allele in chronic hepatitis B group were statistically significant lower than those in asymptomatic HBV carrier group (P = 0.04; P = 0.05), and the frequency of exposure to alcohol consumption in patients with chronic hepatitis B was clearly higher than that in asymptomatic HBV carrier group (P = 0.004). HLA-DQB1*0503 allele and *0303 allele are independently resistant genetic factors to chronic hepatitis B, and alcohol consumption is the risk factor of chronic hepatitis B.

Association of TNF-alpha promoter polymorphisms with the outcomes of hepatitis B virus infection in Chinese Han population

Host genetic factors and environment factors including hepatitis B virus (HBV) genotypes are widely studied for the different outcomes of HBV infection. Recent studies suggest that tumour necrosis factor-alpha (TNF-alpha) plays a pivotal role in the viral clearance and host immune response to HBV, and the capacity for TNF-alpha production in individuals is influenced by a major genetic component. In this study, we aimed to explore whether the single-nucleotide polymorphisms (SNPs) of TNF-alpha promoter are associated with the outcomes of HBV infection in the Chinese Han population. One hundred and forty-three spontaneously recovered HBV subjects and 196 chronic hepatitis B patients were recruited in this case-control study in the Beijing area of China. Polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) and sequence-specific primer-PCR (SSP-PCR) were used to detect the SNPs of five sites in the TNF-alpha promoter (-238G/A, -308G/A, -857C/T, -863C/A, -1031T/C). The frequency distributions of genotypes and haplotypes in two groups were analysed by EPI and EH programs. The presence of the -238GG genotype was significantly correlated with persistence of HBV infection (OR = 4.08, P = 0.02), and -857TT genotype appeared in relation to the spontaneous clearance of HBV (OR = 0.47, P = 0.03). Frequency of haplotype GGCCT (-238/-308/-857/-863/-1031) in the chronic HB group was significantly lower than that in spontaneously recovered group (P = 0.03), and frequencies of haplotypes GGCAT and GGTAT in the chronic HB group were significantly higher than those in the spontaneously recovered group (P = 0.0001, P = 0.0004). In conclusion, TNF-alpha promoter polymorphisms are independently associated with different outcomes of HBV infection.

RSA 2004: Combined Basic Research Satellite Symposium - Session Four: Hepatitis Virus and Alcohol Interactions in Immunity and Liver Disease

This article summarizes the proceedings of the RSA 2004 Combined Basic Research Satellite Meeting convened at the Westin Bayshore Resort and Marina, Vancouver, CA. The session "Hepatitis virus and alcohol interactions in immunity and liver disease" featured four speakers and was chaired by Drs. Diane Lucas and Samuel French. The presentations were 1) Mitochondrial effects of HCV proteins and alcohol by Steve Weinman, 2) Chronic alcohol consumption accelerates viral hepatitis and T-cell hepatitis via dysregulation of cytokine signaling by Bin Gao 3) Interactions between alcohol, hepatitis C virus and innate defense pathways by Steve Polyak and 4) Scavenger Receptor-mediated modulation of the innate and adaptive immune responses following chronic ethanol consumption by Geoffrey Thiele.

Alcoholic hepatitis: from pathogenesis to treatment

Alcoholic hepatitis is a serious complication of alcohol abuse due to its high mortality rates particularly at short term. It may complicate pre-existing alcoholic fatty liver or cirrhosis and is mainly diagnosed on clinical and laboratory grounds although liver biopsy is occasionally needed to exclude other pathology and confirm the diagnosis. Accumulating evidence suggests that cytokines and immunity are actively involved in its pathogenesis. Management includes abstinence and supportive care. Treatment with corticosteroids has been studied in several clinical trials with conflicting results. However, recent evidence supporting the beneficial effect of TNF-alpha inhibition provides an encouraging alternative. Here we summarise the current state in diagnosis and management of alcoholic hepatitis and briefly review the latest advances in pathophysiology that may lead to new therapeutic strategies for this difficult clinical condition.

DATA SOURCES

Medline 1966-2005, EMBASE/Excerpta Medica 1980-2005, The Cochrane Library (2005 Issue 2) and contact with authors of published reports.

Effect of alcohol on viral hepatitis and other forms of liver dysfunction

Alcohol is a known hepatotoxic agent, which may exacerbate liver injury caused by other agents. The wide prevalence of alcohol use and abuse in society makes it an important cofactor in many other liver diseases. Examples of liver diseases that are significantly influenced by ingestion of alcohol include chronic viral hepatitis, disorders of iron overload, and obesity-related liver disease.

Effects of Alcohol Consumption on Osseointegration of Titanium Implants in Rabbits

Alcohol consumption affects bone metabolism by impairing osteoblast proliferation and by increasing osteoclastic activity. The purpose of this study was to evaluate bone formation in alcohol-fed rabbits following the insertion of dental titanium implants. Animals were fed with 20% ethanol sugarcane brandy pre- and postoperatively (group 1), preoperatively only (group 2), and with water as control (group 3). During the postoperative period, rabbits received doses of polyfluorochrome labels (i.e., alizarin, calcein, and tetracycline). Rabbits were killed 8 weeks after the implant insertion. The polyfluorochrome-labeled bone areas in rabbits with alcohol consumption in pre- and postoperative (group 1) and preoperatively only (group 2) were significantly less (P <.05) than in the control group (group 3). The percentage of direct bone-to-implant contact was significantly less in pre- and postoperative (49.5%) and preoperative-only (49.2%) groups than in the control group (64.7%) (P <.05). Alcoholic rabbits demonstrated significantly less bone density and direct bone-to-implant contact.

Association of -238G/A polymorphism of tumor necrosis factor-alpha gene promoter region with outcomes of hepatitis B virus infection in Chinese Han population

AIM: To clarify whether -238G/A polymorphism of tumor necrosis factor-α (TNF-α) gene promoter region was associated with outcomes of hepatitis B virus (HBV) infection in Han population of northern China, and to analyze the gene-environment interaction between -238G/A polymorphism and cigarette smoking or alcohol consumption.

METHODS: A case-control study was conducted to analyze the association of TNF-α gene promoter polymorphism with HBV infection outcomes. A total of 207 patients with chronic hepatitis B (HB) and 148 cases of self-limited HBV infection from Ditan Hospital and Shunyi District Hospital in Beijing, respectively were recruited. History of smoking and alcohol drinking was inquired by a questionnaire. The -238G/A polymorphism of TNF-α gene promoter was genotyped by polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP).

RESULTS: The frequencies of GG and GA genotypes were 98.07% and 1.93% in chronic HB patients and 93.24% and 6.76% in self-limited HBV infection individuals, respectively (χ² = 5.30, P = 0.02). The frequency of G allele was significantly higher in patients with chronic HB that in individuals with self-limited HBV infection (99.03% vs 96.62%, χ² = 5.20, P = 0.02). Only modestly increased risk of onset of chronic HB was found in smokers (OR = 1.40, 95% CI: 0.87-2.28, P = 0.14) and drinkers (OR = 1.26, 95% CI: 0.78-2.05, P = 0.32). There was a positive interaction between genotype GG and cigarette smoking with an interaction index (II) of 2.95, or alcohol consumption with an II of 1.64.

CONCLUSION: The -238G/A polymorphism of TNF-α gene promoter region is independently associated with different outcomes of HBV infection.

Results of common laboratory tests in solvent-exposed workers

OBJECTIVES

The screening and identification of occupational liver or other organ-system injury related to long-term, low-level solvent exposure are difficult in clinical practice. We studied the feasibility of the use of common laboratory tests combined with a detailed exposure history.

METHODS

The relationships between laboratory tests and exposure to organic solvents were studied in regression modelling adjusted to age, alcohol consumption, gender and body mass index (BMI). The subjects were 29 solvent-exposed workers and 19 referents. Laboratory tests included serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), carbohydrate-deficient transferrin (CDT), alkaline phosphatase (ALP), creatinine, cholesterol, HDL-cholesterol, triglycerides, blood glucose and total and conjugated bilirubin. Positive hepatitis serology, systemic diseases or medications with known hepatic effects and current pregnancy were exclusion criteria. The main exposures of each subject were identified. Current solvent exposure status, exposure during the past 3 months, exposure during the past 5 and 10 years, and total life-time exposure were recorded.

RESULTS

AST (P=0.0031), ALT (P=0.0015) and cholesterol (P=0.0110) correlated positively with cumulative solvent exposure in the past 5 years, total bilirubin with current exposure (P=0.0380), and glucose with exposure in the past 5 (P<0.0001) and 10 (P=0.0003) years. Triglycerides correlated positively with exposure in the past 5 (P=0.0025) and 10 (P=0.0059) years and with life-time exposure (P=0.0005). Creatinine correlated negatively with exposure in the past 10 years (P=0.0300) and life-time exposure (P=0.0005). Most laboratory values were within the normal range.

CONCLUSIONS

These results suggest a multi-system health effect of solvents. The laboratory data had some similarities with those in the metabolic syndrome. The screening and diagnostics of solvent-related conditions should be based on a thorough work history and a set of carefully selected laboratory tests. No single test seems sufficient for this purpose.

Microbial infections, immunomodulation, and drugs of abuse

The use of recreational drugs of abuse has generated serious health concerns. There is a long-recognized relationship between addictive drugs and increased levels of infections. Studies of the mechanisms of actions of these drugs became more urgent with the advent of AIDS and its correlation with abused substances. The nature and mechanisms of immunomodulation by marijuana, opiates, cocaine, nicotine, and alcohol are described in this review. Recent studies of the effects of opiates or marijuana on the immune system have demonstrated that they are receptor mediated, occurring both directly via specific receptors on immune cells and indirectly through similar receptors on cells of the nervous system. Findings are also discussed that demonstrate that cocaine and nicotine have similar immunomodulatory effects, which are also apparently receptor mediated. Finally, the nature and mechanisms of immunomodulation by alcohol are described. Although no specific alcohol receptors have been identified, it is widely recognized that alcohol enhances susceptibility to opportunistic microbes. The review covers recent studies of the effects of these drugs on immunity and on increased susceptibility to infectious diseases, including AIDS.

Hepatitis C and alcohol: interactions, outcomes, and implications

BACKGROUND

Alcoholism and chronic hepatitis C (HCV) infection are common causes of liver disease worldwide. Hepatitis C virus and alcohol use frequently coexist, and together lead to more rapid progression of liver disease.

GOALS

To critically review the literature pertaining to the combined effects of alcohol and HCV, focusing primarily on how alcohol influences the natural history, pathogenesis, and treatment of HCV liver disease.

STUDY

A thorough review of the English literature was conducted, using a MEDLINE-based computerized literature search and review of cited references.

RESULTS

Hepatitis C virus is prevalent in unselected alcoholic populations (14-36%) and in alcoholic individuals with liver disease (< or =51%). Hepatitis C virus-infected individuals who drink alcohol in excess have more severe histologic injury, more rapid disease progression, and a higher frequency of cirrhosis and hepatocellular carcinoma. Alcohol use also appears to decrease response rates to interferon therapy. The mechanisms of interaction between alcohol and HCV are not fully understood, but they likely include the effects of alcohol on the host immune system and the virus and on other factors possibly related to HCV liver disease and hepatic carcinogenesis.

CONCLUSIONS

Alcohol use and HCV infection frequently coexist. Although there is ample evidence that alcohol use adversely affects the natural history of HCV liver disease, how the two interact is not well understood. Patients with chronic HCV should be encouraged to avoid alcohol; however, the threshold above which alcohol results in accelerated liver disease remains to be determined.