Hepatitis: Bethesda

Modi AA, Wright EC, Seeff LB. · The National Institute of Diabetes and Digestive and Kidney Diseases, The National Institute of Health, Bethesda, MD, USA. · Antivir Ther. · Pubmed #17591018 No free full text.

Abstract: Complementary and alternative medicine (CAM) has been used for centuries in China and Japan to treat various illnesses, including viral hepatitis. Several therapeutic approaches constitute CAM, the most relevant for this review being the use of herbals. However, profound disagreements exist between conventional and alternative medicine practitioners regarding their value. Western medical advocates cite deep concerns about the purity of most herbals because of lack of standardized production, the paucity of pharmacokinetic data, the fact that few well-designed randomized, controlled trials of these products have been performed and the evidence that some herbals have been responsible for severe adverse effects. Nevertheless, many in the public, even in western countries, turn to the use of herbals, believing that they must be safe and effective because they are 'natural' and have been used for centuries, and because of dissatisfaction with conventional medicine. Accordingly, their use in western countries and the costs incurred have increased each year. While there is evidence that some herbals have physiological effects, there still is insufficient evidence to recommend their use. This paper reviews the classification, epidemiology and philosophy of CAM, and the reasons advanced for herbal use to treat viral hepatitis. The criteria necessary to develop a potential pharmacological agent are presented, as well as the requirements for conducting a scientifically valid treatment trial of herbals. Five herbals used in the past to treat viral hepatitis are reviewed and evaluated for the quality of their studies and mention is made of herbals known to have adverse effects.

Tamayo C, Diamond S. · Research and Development at Flora Inc, Bethesda, MD 20817, USA. · Integr Cancer Ther. · Pubmed #17548793 No free full text.

Abstract: Milk thistle extracts have been used as traditional herbal remedies for almost 2000 years. The extracts are still widely used to protect the liver against toxins and to control chronic liver diseases. Recent experimental and clinical studies suggest that milk thistle extracts also have anticancer, antidiabetic, and cardioprotective effects. This article reviews clinical trials of milk thistle conducted in the past 5 years including pharmacokinetic and toxicity studies, herb-drug interactions, and other safety issues. Several trials have studied the effects of milk thistle for patients with liver diseases, cancer, hepatitis C, HIV, diabetes, and hypercholesterolemia. Promising results have been reported in the protective effect of milk thistle in certain types of cancer, and ongoing trials will provide more evidence about this effect. In addition, new established doses and improvement on the quality and standardization of this herb will provide the much-awaited evidence about the efficacy of milk thistle in the treatment of liver diseases. Milk thistle extracts are known to be safe and well tolerated, and toxic or adverse effects observed in the reviewed clinical trials seem to be minimal. The future of milk thistle research is promising, and high-quality randomized clinical trials on milk thistle versus placebo may be needed to further demonstrate the safety and efficacy of this herb.

Rehermann B. · Immunology Section, Liver Diseases Branch, NIDDK, National Institutes of Health, DHHS, Bethesda, Maryland 20892, USA. · Semin Liver Dis. · Pubmed #17520515 No free full text.

Abstract: Chronic hepatitis B and C cause significant morbidity and mortality worldwide. Antiviral therapy suppresses but does not eliminate chronic hepatitis B virus (HBV) infection, and it is effective in only half of all hepatitis C virus (HCV)-infected patients. Because adaptive immune responses are associated with spontaneous resolution of acute HBV and HCV infection, therapeutic enhancement of immune responses has been proposed as alternative or supplementary therapy for chronic infection. However, all efforts have been hampered by poor proliferation and effector functions of HBV- and HCV-specific CD4 and CD8 T cells, which are thought to be due to T cell exhaustion, high antigenic load, and viral escape. Recent studies revealed that endogenous factors, such as regulatory T cells, immunosuppressive cytokines, and inhibitory receptors, also contribute to the impairment of virus-specific T cell responses in chronic infection, perhaps reflecting the host's attempt to protect itself against immune-mediated pathology. These endogenous mechanisms and potential avenues to revert them are the subject of this review.

Maher SG, Romero-Weaver AL, Scarzello AJ, Gamero AM. · Cancer and Inflammation Program, Laboratory of Experimental Immunology, National Cancer Institute, National Institutes of Health, Frederick, MD 21702-1201, USA. · Curr Med Chem. · Pubmed #17504213 No free full text.

Abstract: Interferons (IFNs) are a family of pleiotropic cytokines that typically exhibit antiviral, antiproliferative, antitumor, and immunomodulatory properties. While their complex mechanisms of action remain unclear, IFNs are used clinically in the treatment of viral infections, such as hepatitis B and hepatitis C, and remain the primary treatment for a limited number of malignancies, such as melanoma, hairy cell leukemia, and non-Hodgkin's lymphoma and in autoimmune diseases such as multiple sclerosis. IFNs not only regulate somatic cell growth and division but also influence cell survival through the modulation of apoptosis. Paradoxically, IFNs are described to be both pro- and anti-apoptotic in nature. The biological effects of IFNs are primarily mediated via activation of the JAK/STAT pathway, formation of the ISGF3 and STAT1:STAT1 protein complexes, and the subsequent induction of IFN-stimulated genes. However, the activation of JAK/STAT-independent signal transduction pathways also contribute to IFN-mediated responses. To further demonstrate the complexity of the downstream events following stimulation, oligonucleotide microarray studies have shown that in excess of 300 genes are induced following treatment with IFN, some of which are crucial to the induction of apoptosis and cell growth control. In this review we describe the recent advances made in elucidating the various signaling pathways that are activated by IFNs and how these diverse signals contribute to the regulation of cell growth and apoptosis and inhibition of viral replication. Furthermore, we highlight the role of specific signaling molecules and the function(s) of particular IFN-stimulated genes that have been implicated in determining cell fate in response to IFN, as well as the clinical experience of IFN immunotherapy.

Bryant BJ, Klein HG. · National Institutes of Health, Warren G. Magnuson Clinical Center, Department of Transfusion Medicine, 10 Center Dr, MSC-1184, Building 10, Room 1C711, Bethesda, MD 20894-1184, USA. · Arch Pathol Lab Med. · Pubmed #17488157 No free full text.

Abstract: CONTEXT: Pathogen inactivation provides a proactive approach to cleansing the blood supply. In the plasma fractionation and manufacturing industry, pathogen inactivation technologies have been successfully implemented resulting in no transmission of human immunodeficiency, hepatitis C, or hepatitis B viruses by US-licensed plasma derivatives since 1985. However, these technologies cannot be used to pathogen inactivate cellular blood components. Although current blood donor screening and disease testing has drastically reduced the incidence of transfusion-transmitted diseases, there still looms the threat to the blood supply of a new or reemerging pathogen. Of particular concern is the silent emergence of a new agent with a prolonged latent period in which asymptomatic infected carriers would donate and spread infection. OBJECTIVE: To review and summarize the principles, challenges, achievements, prospective technologies, and future goals of pathogen inactivation of the blood supply. DATA SOURCES: The current published English-language literature from 1968 through 2006 and a historical landmark article from 1943 are integrated into a review of this subject. CONCLUSIONS: The ultimate goal of pathogen inactivation is to maximally reduce the transmission of potential pathogens without significantly compromising the therapeutic efficacy of the cellular and protein constituents of blood. This must be accomplished without introducing toxicities into the blood supply and without causing neoantigen formation and subsequent antibody production. Several promising pathogen inactivation technologies are being developed and clinically tested, and others are currently in use. Pathogen inactivation offers additional layers of protection from infectious agents that threaten the blood supply and has the potential to impact the safety of blood transfusions worldwide.

Modi AA, Feld JJ. · Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1800, USA. · AIDS Rev. · Pubmed #17474311 No free full text.

Abstract: With increasing access to antiretroviral therapy across sub-Saharan Africa, progress is finally being made in combating the devastating HIV epidemic. As HIV-infected individuals live longer, the effects of coinfection with chronic hepatitis B and C will likely become an increasingly relevant issue. Indeed, HIV adversely affects the natural history of HBV and HCV, both of which are endemic across the African continent, Issues ranging from appropriate diagnostic testing to prevention and treatment are affected by HIV coinfection, particularly in resource-limited settings. In addition, some of the more complex problems such as occult infection, immune reconstitution, and antiretroviral hepatotoxicity are becoming increasingly important considerations. In this review, we present the available data on coinfection in Africa with a major emphasis on prevalence, routes of transmission, prevention and treatment strategies.

Ghany M, Liang TJ. · Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA. · Gastroenterology. · Pubmed #17408658 No free full text.

Abstract: Chronic hepatitis B continues to be a major cause of end-stage liver disease and hepatocellular carcinoma worldwide. Nucleos(t)ide analogues have proven to be effective in controlling the disease and perhaps decreasing the incidence of hepatocellular carcinoma. However, development of drug resistance is a major limitation to their long-term effectiveness. Understanding the mechanisms of drug resistance are important for designing new agents and devising strategies to manage and prevent the development of antiviral drug resistance. The development of resistance is determined by an interplay of viral, host, and drug characteristics Homology of the HBV polymerase to the human immunodeficiency virus-1 reverse transcriptase has allowed predictions to be made on the effect mutations have on HBV polymerase structure. In vitro functional studies provide complementary information. Several broad principles on the mechanism of resistance have emerged from these studies. First, most of the primary mutations cluster in the vicinity of the incoming nucleotide and act by directly affecting the position or stability of the bound substrate, template, or primer. In contrast, secondary mutations tend to occur away from the nucleotide-binding pocket. Finally, the structural and functional consequences of mutations are quite variable among the different agents. This paper reviews the key mutations and mechanisms associated with resistance to the nucleos(t)ide analogues approved for clinical use and discuss new targets for drug development.

Hussain SP, Schwank J, Staib F, Wang XW, Harris CC. · Laboratory of Human Carcinogenesis, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892-4258, USA. · Oncogene. · Pubmed #17401425 No free full text.

Abstract: Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and the major risk factors include chronic infections with the hepatitis B (HBV) or C (HCV) virus, and exposure to dietary aflatoxin B(1) (AFB(1)) or alcohol consumption. Multiple genetic and epigenetic changes are involved in the molecular pathogenesis of HCC, for example, somatic mutations in the p53 tumor suppressor gene (TP53) and the activation of the WNT signal transduction pathway. AFB(1) frequently induces G:C to T:A transversions at the third base in codon 249 of TP53 and cooperates with HBV in causing p53 mutations in HCC. The detection of TP53 mutant DNA in plasma is a biomarker of both AFB(1) exposure and HCC risk. Chronic infection with HBV and HCV viruses, and oxyradical disorders including hemochromatosis, also generate reactive oxygen/nitrogen species that can both damage DNA and mutate cancer-related genes such as TP53. Certain mutant p53 proteins may exhibit a 'gain of oncogenic function'. The p53 biological network is a key responder to this oxidative and nitrosative stress. Depending on the extent of the DNA damage, p53 regulates the transcription of protective antioxidant genes and with extensive DNA damage, transactivates pro-oxidant genes that contribute to apoptosis. The X gene of HBV (HBx) is the most common open reading frame integrated into the host genome in HCC and the integrated HBx is frequently mutated. Mutant HBx proteins still retain their ability to bind to p53, and attenuate DNA repair and p53-mediated apoptosis. In summary, both viruses and chemicals are implicated in the etiology of TP53 mutations during the molecular pathogenesis of HCC.

Huang Y, Staschke K, De Francesco R, Tan SL. · Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA. · Virology. · Pubmed #17400273 No free full text.

Abstract: The hepatitis C virus (HCV) nonstructural 5A (NS5A) phosphoprotein has been intensely studied due to its ability to subvert the host interferon-induced antiviral response. However, more recent studies suggest that it may also play an important regulatory role in HCV RNA replication as well as modulate host intracellular signaling pathways. Phosphorylation of NS5A appears to be a highly regulated process and several cellular protein kinases responsible for NS5A phosphorylation have been identified in vitro. Studies utilizing the HCV replicon cell culture system have suggested a provocative role for the differential phosphorylation of NS5A in the regulation of viral RNA replication through its association with the viral replication complex, including several host cell factors. Importantly, recent in vivo data linking loss of NS5A hyperphosphorylation to non-productive HCV replication in the chimpanzee model have provided high validation for targeting the cellular kinases involved, particularly the kinases responsible for NS5A phosphorylation, for antiviral therapeutic intervention. Understanding the process of NS5A phosphorylation and the definite identification of the culprit cellular protein kinase(s) will shed light on the mechanisms of HCV RNA replication and/or pathogenesis.

Hoofnagle JH, Doo E, Liang TJ, Fleischer R, Lok AS. · Liver Disease Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA. · Hepatology. · Pubmed #17393513 No free full text.

Abstract: Chronic hepatitis B is caused by persistent infection with the hepatitis B virus (HBV), a unique DNA virus that replicates through an RNA intermediate produced from a stable covalently closed circular DNA molecule. Viral persistence appears to be due to inadequate innate and adaptive immune responses. Chronic infection has a variable course after several decades resulting in cirrhosis in up to one-third of patients and liver cancer in a proportion of those with cirrhosis. Sensitive assays for HBV DNA levels in serum have been developed that provide important insights into pathogenesis and natural history. Therapy of hepatitis B is evolving. Peginterferon induces long-term remissions in disease in one-third of patients with typical hepatitis B e antigen (HBeAg) positive chronic hepatitis B, but a lesser proportion of those without HBeAg. Several oral nucleoside analogues with activity against HBV have been shown to be effective in suppressing viral levels and improving biochemical and histological features of disease in a high proportion of patients with and without HBeAg, at least in the short term. What is uncertain is which agent or combination of agents is most effective, how long therapy should last, and which criteria should be used to start, continue, switch or stop therapy. Long-term therapy with nucleoside analogues may be the most appropriate approach to treatment, but the expense and lack of data on long-term safety and efficacy make recommendations difficult. Clearly, many basic and clinical research challenges remain in defining optimal means of management of chronic hepatitis B.

Engels EA. · Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Department of Health and Human Services, 6120 Executive Boulevard, EPS 7076, Rockville, MD 20852, USA. · Cancer Epidemiol Biomarkers Prev. · Pubmed #17337646 links to  free full text

Abstract: Among exposures presently viewed as possible etiologic factors in non-Hodgkin lymphoma (NHL), infections are close to being regarded as established causes. Infectious agents causing NHL can be classified, according to mechanism, into three broad groups. First, some viruses can directly transform lymphocytes. Lymphocyte-transforming viruses include Epstein Barr virus (linked to Burkitt's lymphoma, NHLs in immunosuppressed individuals, and extranodal natural killer/T-cell NHL), human herpesvirus 8 (primary effusion lymphoma), and human T lymphotropic virus type I (adult T-cell leukemia/lymphoma). Second, human immunodeficiency virus is unique in causing profound depletion of CD4+ T lymphocytes, leading to acquired immunodeficiency syndrome and an associated high risk for some NHL subtypes. Third, recent evidence suggests that some infections increase NHL risk through chronic immune stimulation. These infections include hepatitis C virus as well as certain bacteria that cause chronic site-specific inflammation and seem to increase risk for localized mucosa-associated lymphoid tissue NHLs. Establishing that an infectious agent causes NHL depends on showing that the agent is present in persons with NHL as well as laboratory experiments elucidating the mechanisms involved. Only epidemiologic studies can provide evidence that infection is actually a risk factor by showing that infection is more frequent in NHL cases than in controls. Given the range of mechanisms by which infections could plausibly cause NHL and our growing molecular understanding of this malignancy, this field of research deserves continued attention.

Alter HJ, Stramer SL, Dodd RY. · Infectious Diseases Section and Department of Transfusion Medicine, National Institutes of Health, Bethesda, MD 20892, USA. · Semin Hematol. · Pubmed #17198845 No free full text.

Abstract: Following the devastating effects of blood-transmitted human immunodeficiency virus (HIV), blood establishments have become increasingly vigilant for the emergence or re-emergence of new threats to the safety of the blood supply. Many agents have fulfilled the broad definition of emerging blood-transmitted infections, including West Nile virus (WNV), Trypanosoma cruzi, Plasmodium spp., Babesia spp., parvovirus B19, dengue virus, and the prions that cause variant Creutzfeld-Jacob disease (vCJD). Other agents such as human herpes virus-8 (HHV-8-Kaposi's sarcoma virus) and Borellia (Lyme disease) and, perhaps, avian flu virus, are known to have a viremic phase, but have not yet been proved to be transfusion-transmitted. In the wake of these threats, transfusion services use a variety of donor screening interventions, including serologic assays, nucleic acid assays, and geographic exclusions based on potential exposure. The ultimate safeguard may be a pre-emptive pathogen inactivation strategy that will disrupt all nucleic acid-containing agents (though not prions). Considerable effort and resources have been invested in this arena, but currently no single technique is effective for inactivation of both liquid and cellular blood products and toxicity issues have not been completely resolved. The blood supply is remarkably safe with the risk of major pathogens such as hepatitis C virus (HCV) and HIV now reduced to less than one transmission per 2 to 3 million exposures. However, to approach near-zero infectious disease risk for emerging and re-emerging pathogens, new strategies such as pathogen inactivation or multi-pathogen microarray technology will need to be developed or refined.

Hoofnagle JH, Seeff LB. · Liver Disease Research Branch, Division of Digestive Diseases and Nutrition, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA. · N Engl J Med. · Pubmed #17151366 No free full text.

This publication has no abstract.

Budhu A, Wang XW. · National Cancer Institute, 37 Convent Dr., Bldg. 37, Rm. 3044A, Bethesda, MD 20892, USA. · J Leukoc Biol. · Pubmed #16946019 links to  free full text

Abstract: Hepatocellular carcinoma (HCC) is a frequent malignancy worldwide with a high rate of metastasis. The hepatitis B and C viruses are considered major etiological factors associated with the development of HCC, particularly as a result of their induction of chronic inflammation. There is increasing evidence that the inflammatory process is inherently associated with many different cancer types, including HCC. Specifically, this review aims to cover evidence for the potential roles of cytokines, an important component of the immune system, in promoting HCC carcinogenesis and progression. A global summary of cytokine levels, functions, polymorphisms, and therapies with regard to HCC is presented. In particular, the role of proinflammatory Th1 and anti-inflammatory Th2 cytokine imbalances in the microenvironment of HCC patients with metastasis and the possible clinical significance of these findings are addressed. Overall, multiple studies, spanning many decades, have begun to elucidate the important role of cytokines in HCC.

Wang HC, Huang W, Lai MD, Su IJ. · Division of Clinical Research, National Health Research Institutes, National Cheng Kung University College of Medicine, Tainan 704, Taiwan. · Cancer Sci. · Pubmed #16863502 No free full text.

Abstract: Although hepatitis B virus (HBV) has been documented to cause hepatocellular carcinoma (HCC), the exact role of HBV in the development of HCC remains enigmatic. Several hypotheses have been proposed to explain the potential mechanism, including insertional mutagenesis of HBV genomes and transcriptional activators of HBV gene products such as hepatitis B x protein (HBx) and truncated middle S mutants. In the past few years, we have identified two types of large HBV surface antigens (LHBs) with deletions at the pre-S1 (DeltaS1-LHBs) and pre-S2 (DeltaS2-LHBs) regions in ground glass hepatocytes. The pre-S mutant LHBs are retained in the endoplasmic reticulum (ER) and escape from immune attack. The pre-S mutants, particularly DeltaS2-LHBs, are increasingly prevalent in patients with hepatitis B e antigen (HBeAg)-positive chronic HBV infection, ranging from 6% before the 3rd decade to 35% in the 6th decade. In HCC patients, the two pre-S mutants were detected in 60% of HCC patients, in the serum and in HCC tissues. Pre-S mutant LHBs can initiate ER stress to induce oxidative DNA damage and genomic instability. Furthermore, pre-S mutant LHBs can upregulate cyclooxygenase-2 and cyclin A to induce cell cycle progression and proliferation of hepatocytes. In transgenic mice, the pre-S mutants can induce dysplasia of hepatocytes and development of HCC. In a nested control study, the presence of pre-S mutants carried a high risk of developing HCC in HBV carriers. In summary, the findings we describe in this review suggest a potential role for HBV pre-S mutants in HBV-related hepatocarcinogenesis, providing a model of viral carcinogenesis associated with ER stress.

Robertson SJ, Hasenkrug KJ. · Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South 4th St., Hamilton, MT 59840, USA. · Springer Semin Immunopathol. · Pubmed #16841143 No free full text.

Abstract: In recent years, regulatory T cells have received increased attention for their role in immune responses to microbial infections. The list of microbial pathogens associated with regulatory T cell responses is growing rapidly and includes bacteria, viruses, parasites, and fungi. As the biology of regulatory T cells is revealed, we are discovering that their induction during infection is a normal aspect of immunity, necessary to limit collateral damage from inflammatory responses and aggressive immunological effectors. Thus, these cells play a critical role in maintaining the delicate balance between preventing immunopathology and allowing the immune response to clear infections. While generally successful, there are notable exceptions where regulatory T cell-mediated suppression appears to be responsible for allowing certain viruses to establish and maintain a persistent state. In this review, we will discuss our current understanding of what virus-induced regulatory T cells are, how they are induced, and what mechanisms they use to suppress immunity. The complex role of Tregs in regulating immunity to viral infections, and the consequences their activity has on disease is illustrated by a review of specific viral infections including hepatitis C virus and human immunodeficiency virus.

Wick JY, Zanni GR. · National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA. · Consult Pharm. · Pubmed #16824001 No free full text.

Abstract: Disease researchers use animal models to study potential etiologies, pathophysiologies, and treatments. Responsive models must be predictable, emulating human conditions, and produce results that can be extrapolated and transposed. These models are often better than in vitro study or computer models, but still have limitations. Animal models can be difficult to maintain and are usually quite costly. Numerous methods are used to develop animal models including chemical exposure, genetic "knockout or knock in," or forward genetic modeling. Recently, more accurate animal models of Alzheimer's disease, osteoporosis, cancer, and mental illness have been developed. The strengths and limitations of each are discussed.

Shin EC. · Immunology Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA. · Korean J Hepatol. · Pubmed #16804339 links to  free full text

Abstract: Hepatitis C virus (HCV) infection is a worldwide problem in terms of public health. It causes chronic hepatitis C in 60-80% of patients after acute hepatitis C. Chronic hepatitis C can progress to liver cirrhosis and hepatocellular carcinoma. In the present time, combination therapy of pegylated interferon-alpha and ribavirin is the standard therapy for hepatitis C, but it results in sustained virologic response only in 45-80% of treated patients. In addition, there is no available effective vaccine for HCV. To develop effective immunotherapy or preventive vaccine, understanding of the immune response against HCV is prerequisite. Among several components of immune system, T cells play a key role in the clearance of HCV and immunopathology during hepatitis C. In the study of HCV infection, however, the most important limiting factor is the absence of small animal model as only humans and chimpanzees can be infected by HCV. In this review, T cell response against HCV, which has been known from the studies of the HCV-infected patients and chimpanzees, will be discussed in several circumstances, including acute hepatitis C, chronic hepatitis C and recovered status from hepatitis C.

Seeff LB, Hoofnagle JH. · Liver Disease Research Branch, Division of Digestive Diseases and Nutrition, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA. · Oncogene. · Pubmed #16799618 No free full text.

Abstract: Hepatocellular carcinoma (HCC) ranks among the 10 most common cancers worldwide. It evolves from several chronic liver diseases, most of which culminate in cirrhosis. As the most common causes, other than alcoholic cirrhosis, are chronic hepatitis B and C infections, its prevalence worldwide is linked to the prevalence of these two viruses. Thus, the highest rates are in southeast Asia and sub-Saharan Africa, the world's most populous nations, where hepatitis B virus infection is endemic. In most western countries, hepatitis C virus infection is the predominant cause, and hepatitis B-related liver cancer occurs largely among immigrants from countries of high hepatitis B endemicity. In most western countries, the incidence and mortality from HCC is increasing as a consequence of the chronic sequelae of the 'epidemic' of hepatitis C of the 1960-1980s. In the US, modeling of this infection predicts a continued rise in liver cancer over the next decade. Surveillance by the National Cancer Institute and the Centers for Disease Control confirms the increasing incidence of and mortality from HCC to the year 2000, although subsequent analyses suggest a slowing or possibly decline in the rate of increase. Whether this trend will continue requires further evaluation.

Shiina M, Rehermann B. · Immunology Section, Liver Diseases Branch NIDDK, National Institutes of Health, DHHS, Bethesda, MD, USA. · Hepatology. · Pubmed #16729320 No free full text.

Abstract: Three percent of the world's population is chronically infected with the hepatitis C virus (HCV) and at risk of developing liver cancer. Effective cellular immune responses are deemed essential for spontaneous resolution of acute hepatitis C and long-term protection. Here we describe a new T-cell HCV genetic vaccine capable of protecting chimpanzees from acute hepatitis induced by challenge with heterologous virus. Suppression of acute viremia in vaccinated chimpanzees occurred as a result of massive expansion of peripheral and intrahepatic HCV-specific CD8+ T lymphocytes that cross-reacted with vaccine and virus epitopes. These findings show that it is possible to elicit effective immunity against heterologous HCV strains by stimulating only the cellular arm of the immune system, and suggest a path for new immunotherapy against highly variable human pathogens like HCV, HIV or malaria, which can evade humoral responses.

Feld JJ, Heathcote EJ. · Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, Bethesda, Maryland, USA. · Semin Liver Dis. · Pubmed #16673290 No free full text.

Abstract: The natural history of hepatitis B e antigen (HBeAg)-positive chronic hepatitis B is very heterogeneous. Age at acquisition is a major factor in determining the natural history of chronic infection. The vigor of the host immune response to the virus, viral factors (genotype, core promoter mutations, and duration of viral replication) as well as exogenous factors (alcohol, immune suppression) all influence the severity of disease. The goal of antiviral therapy is HBeAg seroconversion, and preferably HB surface Ag seroconversion as this latter end-point is associated with sustained immune control and the halting of disease progression. Although peginterferon is now considered as the first line of therapy for HBeAg-positive chronic hepatitis B, in most cases there are circumstances where nucleos(t)ide analogues are indicated (e.g., decompensated liver disease) for those requiring cancer chemotherapy/other immunosuppressive agents and for those with contraindications to interferon. The major challenge for the clinician using these agents is the emergence of antiviral drug resistance. Long-term immune control of viral replication is key to improving patient outcome.

Loomba R, Liang TJ. · Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA. · Antivir Ther. · Pubmed #16518955 No free full text.

Abstract: Hepatitis B is one of the most prevalent viral diseases in the world. It leads to chronic liver disease in 10% of infected individuals, putting them at an increased risk for liver-related morbidity and mortality from complications of cirrhosis and hepatocellular carcinoma. Despite the success of universal hepatitis B vaccination in many countries, this disease remains a major public health problem, resulting in more than 500,000 deaths per year. Although the current therapy for chronic hepatitis B (CHB) is effective, it is not optimal; novel approaches to the management of CHB are needed. An improved understanding of virus-host interactions, advances in gene therapy, the development of molecular therapies targeted at different stages of the hepatitis B virus life cycle, and new insights into various approaches of immune modulation will lead to the development of better therapeutic agents for the management of CHB. These advances herald a new era of combination therapy. In this review, we will discuss emerging therapies and potential mechanisms, and highlight the promises and pitfalls of these new treatment strategies.

Purohit V, Brenner DA. · Division of Metabolism and Health Effects, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA. · Hepatology. · Pubmed #16502397 No free full text.

Abstract: This report is a summary of Ron Thurman Symposium on the Mechanisms of Alcohol-Induced Hepatic Fibrosis which was organized by The National Institutes of Health in Santa Barbara, California, June 25, 2005. The Symposium and this report highlight the unique aspects by which drinking alcoholic beverages may result in hepatic fibrosis. Acetaldehyde, the first metabolite of ethanol, can upregulate transcription of collagen I directly as well as indirectly by upregulating the synthesis of transforming growth factor-beta 1 (TGF-beta1). Reactive oxygen species (ROS) generated in hepatocytes by alcohol metabolism can activate collagen production in hepatic stellate cells (HSCs) in a paracrine manner. Alcohol-induced hepatocyte apoptotic bodies can be phagocytosed by HSCs and Kupffer cells and result in increased expression of TGF-beta1 and subsequent HSC activation. Kupffer cells may contribute to the activation of HSCs by releasing ROS and TGF- beta1. Innate immunity may suppress hepatic fibrosis by killing activated HSCs and blocking TGF-beta1 signaling. In patients infected with hepatitis C virus (HCV), alcohol may promote hepatic fibrosis by suppressing innate immunity. HCV core and non-structural proteins contribute to HCV-induced hepatic fibrosis. Alcohol and HCV together may promote hepatic fibrosis through increased oxidative stress and upregulation of fibrogenic cytokines. The inactive aldehyde dehydrogenase (ALDH2) and the super-active alcohol dehydrogenase (ADH2) alleles may promote hepatic fibrosis through increased accumulation of acetaldehyde in the liver. Hepatic fibrosis can be reversed by inducing selective apoptosis or necrosis of activated HSCs, or by reverse trans-differentiation of activated HSCs into the quiescent phenotype.

Alter H. · National Institutes of Health, Bethesda, MD 20892, USA. · Hepatology. · Pubmed #16447286 No free full text.

This publication has no abstract.

Feld JJ, Liang TJ. · Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA. · Hepatology. · Pubmed #16447261 No free full text.

Abstract: Hepatitis C follows a variable course with some patients developing progressive liver fibrosis, cirrhosis and hepatocellular carcinoma, while others have minimal or no significant liver disease after decades of infection. Studies have identified both host and viral factors associated with disease progression. The importance of general factors such as age at infection, gender, immune status and alcohol consumption has long been recognized; however recently, polymorphisms in a wide array of genes have also been shown to be associated with progressive fibrosis. How specific viral proteins may contribute to disease progression has also been studied. This review highlights what is currently known about the factors associated with progressive liver injury in patients with hepatitis C. A greater understanding of the determinants of disease progression will hopefully lead to improved utilization of existing treatments and ultimately may aid in identification of new therapeutic targets.