丙型肝炎病毒包膜糖蛋白的研究进展

本文概述了近年来利用体外表达系统对丙型肝炎病毒(HCV)包膜糖蛋白的翻译后加工、折叠、装配的研究进展。目前的研究表明:HCV E1、E2蛋白通过非共价键相连形成的异源二聚体代表了HCV糖蛋白的天然构象;E1和E2 C末端的跨膜区能使其锚定于内质网;HCV包膜糖蛋白在内质网中完成其加工及成熟的过程;分子伴侣及E1、E2蛋白的旁侧序列对形成天然HCV包膜糖蛋白复合物起重要作用。

Liver insulin-like growth factor 2 methylation in hepatitis C virus cirrhosis and further occurrence of hepatocellular carcinoma

AIM: To assess the predictive value of the insulinlike growth factor 2 (Igf2) methylation profile for the occurrence of Hepatocellular Carcinoma (HCC) in hepatitis C (HCV) cirrhosis. METHODS: Patients with: (1) biopsy-proven compensated HCV cirrhosis; (2) available baseline frozen liver sample; (3) absence of detectable HCC; (4) regular screening for HCC; (5) informed consent for genetic analysis were studied. After DNA extraction from liver samples and bisulfite treatment, unbiased PCR and DHPLC analysis were performed for methylation analysis at the Igf2 locus. The predictive value of the Igf2 methylation profile for HCC wasassessed by Kaplan-Meier and Cox methods. RESULTS: Among 94 included patients, 20 developed an HCC during follow-up (6.9 ± 3.2 years). The methylation profile was hypomethylated, intermediate and hypermethylated in 13, 64 and 17 cases, respectively. In univariate analysis, two baseline parameters were associated with the occurrence of HCC: age (P = 0.01) and prothrombin (P = 0.04). The test of linear tendency between the three ordered levels of Igf2 methylation and probability of HCC occurrence was significant (Log Rank, P = 0.043; Breslow, P = 0.037; Tarone-Ware, P = 0.039). CONCLUSION: These results suggest that hypomethylation at the Igf2 locus in the liver could be predictive for HCC occurrence in HCV cirrhosis.

Safety of lamivudine treatment for chronic hepatitis B in early pregnancy

AIM:To evaluate the safety of lamivudine(LAM) treatment for chronic hepatitis B in early pregnancy.METHODS:A total of 92 pregnant women who received LAM treatment either before pregnancy or in early pregnancy were enrolled in this study.All of the pregnant women volunteered to take lamivudine during pregnancy and were not co-infected with hepatitis C virus,human immunodeficiency virus,cytomegalovirus,or other viruses.All infants received passiveactive immunoprophylaxis with 200 IU hepatitis B immunoglobulin and three doses of 10 μg hepatitis B vaccines(0-1-6 mo) according to the guidelines for the prevention and treatment of chronic hepatitis B.Adverse events were observed throughout the entire pregnancy and perinatal period,and the effectiveness of lamivudine treatment for blocking mother-to-infant transmission of hepatitis B virus(HBV) was evaluated.All adverse events in mothers and infants during pregnancy and the perinatal period and the HBV motherto-infant transmission blocking rate were compared with the literature.RESULTS:Among the 92 pregnant women,spontaneous abortions occurred in 11 cases,while 3 mothers had a second pregnancy after the initial abortion;72 mothers delivered 73 live infants,of whom 68 infants were followed up for no less than 6 mo,and 12 mothers were still pregnant.During pregnancy,the main maternal adverse events were vaginitis(12/72,16.7%),spontaneous abortion(11/95,11.6%),and gestational diabetes(6/72,8.3%);only one case had 1-2 degree elevation of the creatine kinase level(195 U/L).During the perinatal period,the main maternal adverse events were premature rupture of the membranes(8/72,11.1%),preterm delivery(5/72,6.9%),and meconium staining of the amniotic fluid(4/72,5.6%).In addition,2 infants were found to have congenital abnormalities;1 had a scalp hemangioma that did not change in size until 7 mo,and the other had early cerebral palsy,but with rehabilitation training,the infant's motor functions became totally normal at 2 years of age.The incidence of adverse events among the mothers or abnormalities in the infants was not higher than that of normal mothers or HBV-infected mothers who did not receive lamivudine treatment.In only 2 cases,mother-to-infant transmission blocking failed;the blocking rate was 97.1%(66/68),which was higher than has been previously reported.CONCLUSION:Lamivudine treatment is safe for chronic HBV-infected pregnant mothers and their fetuses with a gestational age of less than 12 wk or throughout the entire pregnancy.

Impact of human immunodeficiency virus infection on the course of hepatitis C virus infection: A meta-analysis

AIM: To analyze the influence of human immunodeficiency virus (HIV) infection on the course of hepatitis C virus (HCV) infection. METHODS: We performed a meta-analysis to quantify the effect of HIV co-infection on progressive liver disease in patients with HCV infection. Published studies in the English or Chinese-language medical literature involving cohorts of HIV-negative and -positive patients coinfected with HCV were obtained by searching the PUBMED, EMBASE and CBM. Data were extracted independently from relevant studies by 2 investigators and used in a fixed-effect meta analysis to determine the difference in the course of HCV infection in the 2 groups. RESULTS: Twenty-nine trails involving 16 750 patients were identified including the outcome of histological fibrosis or cirrhosis or de-compensated liver disease or hepatocellular carcinoma or death. These studies yielded a combined adjusted odds ratio (OR) of 3.40 [95% confidence interval (CI) = 2.45 and 4.73]. Of note, studies that examined histological fibrosis/ cirrhosis, decompensated liver disease, hepatocellular carcinoma or death had a pooled OR of 1.47 (95% CI = 1.27 and 1.70), 5.45 (95% CI = 2.54 and 11.71), 0.76 (95% CI = 0.50 and 1.14), and 3.60 (95% CI = 3.12 and 4.15), respectively. CONCLUSION: Without highly active antiretroviral therapies (HAART), HIV accelerates HCV diseaseprogression, including death, histological fibrosis/ cirrhosis and decompensated liver disease. However, the rate of hepatocellular carcinoma is similar in persons who had HCV infection and were positive for HIV or negative for HIV.

Mechanisms of alcohol-mediated hepatotoxicity in human-immunodeficiency-virus-infected patients

Clinical observations have demonstrated that excessive chronic alcohol use negatively affects human immuno- deficiency virus (HIV) infection and contributes to the liver manifestations of the disease, even in HIV mono- infection. HIV/hepatitis C virus (HCV) co-infection is as- sociated with increased progression of HVC liver disease compared to HCV infection alone, and both of these are negatively affected by alcohol use. Recent data suggest that alcohol use and HIV infection have common targets that contribute to progression of liver disease. Both HIV infection and chronic alcohol use are associated with increased gut permeability and elevated plasma levels of lipopolysaccharide; a central activator of inflammatory responses. Both alcoholic liver disease and HIV infec tionresult in non-specific activation of innate immunity, proinflammatory cytokine cascade upregulation, as well as impaired antigen presenting cell and dendritic cell functions. Finally, alcohol, HIV and antiretroviral therapyaffect hepatocyte functions, which contributes to liver damage. The common targets of alcohol and HIV infection in liver disease are discussed in this minireview.

Hepatitis B and C infection and liver disease trends among human immunodeficiency virus-infected individuals

AIM:To examine trends in and correlates of liver disease and viral hepatitis in an human immunodeficiency virus (HIV)-infected cohort. METHODS:The multi-site adult/adolescent spectrum of HIV-related diseases (ASD) followed 29 490 HIVinfected individuals receiving medical care in 11 U.S. metropolitan areas for an average of 2.4 years,and a total of 69 487 person-years,between 1998 and 2004. ASD collected data on the presentation,treatment,and outcomes of HIV,including liver disease,hepatitis screening,and hepatitis diagnoses. RESULTS:Incident liver disease,chronic hepatitis B virus (HBV),and hepatitis C virus (HCV) were diagnosed in 0.9,1.8,and 4.7 per 100 person-years. HBV and HCV screening increased from fewer than 20% to over 60% during this period of observation (P < 0.001). Deaths occurred in 57% of those diagnosed with liver disease relative to 15% overall (P < 0.001). Overall 10% of deaths occurred among individuals with a diagnosis of liver disease. Despite care guidelines promoting screening and vaccination for HBV and screening for HCV,screening and vaccination were not universally conducted or,if conducted,not documented. CONCLUSION:Due to high rates of incident liver disease,viral hepatitis screening,vaccination,and treatment among HIV-infected individuals should be a priority.

Use of agents stimulating erythropoiesis in digestive diseases

Anemia is the most common complication of inflammatory bowel disease (IBD). Control and inadequate treatment leads to a worse quality of life and increased morbidity and hospitalization. Blood loss, and to a lesser extent, malabsorption of iron are the main causes of iron def iciency in IBD. There is also a variable component of anemia related to chronic inflammation. The anemia of chronic renal failure has been treated for many years with recombinant human erythropoietin (rHuEPO), which significantly improves quality of life and survival. Subsequently, rHuEPO has been used progressively in other conditions that occur with anemia of chronic processes such as cancer, rheumatoid arthritis or IBD, and anemia associated with the treatment of hepatitis C virus. Erythropoietic agents complete the range of available therapeutic options for treatment of anemia associated with IBD, which begins by treating the basis of the inflammatory disease, along with intravenous iron therapy as f irst choice. In cases of resistance to treatment with iron, combined therapy with erythropoietic agents aims to achieve near-normal levels of hemoglobin/hematocrit (11-12 g/dL). New formulations of intravenous iron (iron carboxymaltose) and the new generation of erythropoietic agents (darbepoetin and continuous erythropoietin receptor activator) will allow better dosing with the same eff icacy and safety.

Ion Channels as Antivirus Targets

Ion channels are membrane proteins that are found in a number of viruses and which are of crucial physiological importance in the viral life cycle. They have one common feature in that their action mode involves a change of electrochemical or proton gradient across the bilayer lipid membrane which modulates viral or cellular activity. We will discuss a group of viral channel proteins that belong to the viroproin family, and which participate in a number of viral functions including promoting the release of viral particles from cells. Blocking these channel-forming proteins may be ＂lethal＂, which can be a suitable and potential therapeutic strategy. In this review we discuss seven ion channels of viruses which can lead serious infections in human beings： M2 of influenza A, NB and BM2 of influenza B, CM2 of influenza C, Vpu of HIV-1, p7 of HCV and 2B of picomaviruses.

An annual topic highlight: Alcohol and liver, 2011

An annual topic highlight: Alcohol and Liver, 2011, covers the important and new aspects of pathogenesis of alcoholic liver diseases (ALD). It includes broad topics ranging from the exacerbation of ALD by infectious (viral) agents (hepatitis C virus and human immunodeficiency virus) to the influence of alcohol on liver fibrogenesis, lipid rafts, autophagy and other aspects. This issue is recommended for both basic scientists and clinicians who are involved in alcoholic liver research.

DNA sequences homologous to hepatitis C virus(HCV) in the extrachromosomal circular DNA in peripheral blood mononuclear cells of HCV-negative subjects

Objective: This study aimed to investigate DNA sequences that are substantially homologous to the corresponding RNA sequence sections of the hepatitis C virus (HCV). These DNA sequences are present in the whole DNA extracted from peripheral blood mononuclear cells (PBMCs) of HCV-negative subjects. We presumed that these experimentally proven 5'-noncoding region (5'-NCR) homologous DNA sequences could be contained in the extrachromosomal circular DNA (eccDNA) fraction as part of the whole cellular DNA. Methods: Home-made polymerase chain reaction (PCR) with whole cellular and isolated eccDNA, nucleotide basic local alignment search tool (BLASTn) alignments, and tests for patterns of methylation in selected sequence sections were performed. Results: The PCR tests revealed DNA sequences of up to 320 bp that broadly matched the corresponding sequence sections of known HCV genotypes. In contrast, BLASTn alignment searches of published HCV 5'-NCR sequences with human genome databases revealed only sequence segments of up to 36 bp of the 5'-NCR. The composition of these sequences shows missing base pairs, base pair mismatches as well as complete homology with HCV reference sequences. These short sequence sections are present in numerous copies on both the same and different chromosomes. The selected sequence region within the DNA sequences of the 5'-NCR revealed a broad diversity of individual patterns of methylation. Conclusions: The experimental results confirm our assumption that parts of the HCV 5'-NCR genomic RNA sequences are present at the DNA level in the eccDNA fraction of PBMCs. The tests for methylation patterns therein revealed individual methylomes which could represent an epigenetic feature. The respective sequence section might be subject to genetic regulation.