Hepatitis B in China： from Guideline to Practice

Chronic hepatitis B infection is a very important health problem in China, which is carrying an enormous economic and social burdens. The major routs of chronic hepatitis B infection in China are mother-infant vertical transmission and early childhood horizontal transmission. After more than 10 years implementation of universal vaccination against hepatitis B in newborns and safety injection in health care settings, the prevalence of HBsAg in general population has decreased from 9.75% to around 7%. In China, patients with hepatitis are cared by either hepatologists or physicians of infectious diseases. The Chinese Society of Hepatology, and Chinese Society of Infectious Diseases jointly issued an evidence-based guideline on the prevention and treatment of chronic hepatitis B in 2005. This guideline concisely describes the virology, epidemiology, natural history and prevention, as well as diagnosis and management of chronic hepatitis B. It also highlights the importance of active viral replication in disease progression in chronic HBV infection and explicitly states the necessity of antiviral therapy in patient care. The cornerstone of anti-hepatitis B therapy is optimal use of interferons or nucleos(t)ide analogs in those patients with active viral replication and elevated serum transaminase levels. Through an independent continue medical educational agency, a panel of selected speakers were trained to give well-formatted talks on the key points of the guideline in over 60 major cities across China. This educational campaign among health care providers has greatly improved the awareness and the stand of care for antiviral therapy.     

Antisense therapy of hepatitis B virus infection

Chronic infection with the hepatitis B virus (HBV) is a major health problem worldwide. The only established therapy is interferon-a with an efficacy of only 30–40% in highly selected patients. The discovery of animal viruses closely related to the HBV has contributed to active research on antiviral therapy of chronic hepatitis B. The animal model tested and described in this article are Peking ducks infected with the duck hepatitis B virus (DHBV). Molecular therapeutic strategies aimed at blocking gene expression include antisense DNA. An antisense oligodeoxynucleotide directed against the 5′-region of the preS gene of DHBV inhibited viral replication and gene expression in vitro in primary duck hepatocytes and in vivo in Peking ducks. These results demonstrate the potential clinical use of antisense DNA as antiviral therapeutics.     

Antibodies to the RNase H domain of hepatitis B virus P protein are associated with ongoing viral replication.

Antibodies against the RNase H domain of human hepatitis B virus P protein(s) are frequent markers of acute and chronic virus infection (T. Weimer, K. Weimer, Z.-X. Tu, M.-C. Jung, G. R. Pape, and H. Will, J. Immunol. 143:3750-3756, 1989). In the present study, these antibodies were determined in serial serum samples of experimentally infected chimpanzees and naturally infected human patients with acute and chronic hepatitis B virus infection. Anti-P antibodies were found in the sera of both chimpanzees and humans early in infection shortly after the immunoglobulin M anti-HBc response; they persisted in chronic carriers with ongoing viral replication but declined and disappeared at the time of virus clearance from the sera. These data demonstrate that antibodies to the RNase H domain of the hepatitis B virus P protein are early markers of infection and a signal of ongoing virus replication. Falling titers indicate the decline or end of active virus production and may therefore be a prognostic sign of virus elimination in natural infection and after antiviral therapy.     

New therapeutic vaccination strategies for the treatment of chronic hepatitis B

Chronic hepatitis B virus (CHB) is currently treated with either interferon-based or nucleot(s)ide-based antiviral therapies. However, treatment with pegylated interferon alpha results in a durable antiviral response in only about 30% patients and is associated with side effects. Most patients receiving nucleot(s)ide analogue treatment do not establish long-term, durable control of infection and have rebounding viremia after cessation of therapy. Thus, novel therapy strategies are necessary to achieve the induction of potent and durable antiviral immune responses of the patients which can maintain long-term control of viral replication. Therapeutic vaccination of HBV carriers is a promising strategy for the control of hepatitis B. Here the authors review new therapeutic vaccination strategies to treat chronic hepatitis B which may be introduced for patient treatment in the future.     

The Role of Viral Mutation in the Pathogenesis of Chronic Viral Hepatitis

The quasispecies nature of hepatitis B and C virus (HBV, HCV) plays an important role in the pathogenesis, immune escape and drug resistance during chronic infection. Although there is still a lack of effective treatment for hepatitis C, a series of nucleoside analogs (NA) have been developed for the treatment of hepatitis B. NA resistant HBV mutants can accumulate during prolonged therapy and lead to the failure of anti-HBV therapy. Switching to other sensitive NAs can inhibit the emerged resistant mutants. Therefore, understanding the evolution of viral quasispecies under drug pressure is crucial for the establishment of antiviral strategy and the monitoring of antiviral process. Immune response and escape are complicated process, during which both host and virus factors may play their roles. Further understanding of the interaction and interrelationship between host and these viruses may lead to optimized prevention, diagnosis and treatment for chronic hepatitis.     

The role of viral mutation in the pathogenesis of chronic viral hepatitis

The quasispecies nature of hepatitis B and C virus (HBV, HCV) plays an important role in the pathogenesis, immune escape and drug resistance during chronic infection. Although there is still a lack of effective treatment for hepatitis C, a series of nucleoside analogs (NA) have been developed for the treatment of hepatitis B. NA resistant HBV mutants can accumulate during prolonged therapy and lead to the failure of anti-HBV therapy. Switching to other sensitive NAs can inhibit the emerged resistant mutants. Therefore, understanding the evolution of viral quasispecies under drug pressure is crucial for the establishment of antiviral strategy and the monitoring of antiviral process. Immune response and escape are complicated process, during which both host and virus factors may play their roles. Further understanding of the interaction and interrelationship between host and these viruses may lead to optimized prevention, diagnosis and treatment for chronic hepatitis.     

Inhibition of Hepatitis B Virus cccDNA by siRNA in Transgenic Mice

The elimination of viral covalently closed circular DNA (cccDNA) from the nucleus of infected hepatocytes is an obstacle to achieving sustained viral clearance during antiviral therapy of chronic hepatitis B virus (HBV) infection. The aim of our study was to determine whether treatment with siRNA is able to suppress viral cccDNA amplification using a HBV-transgenic mice model. The experimental results revealed that siRNAs can serve as efficient alternative anti-HBV agents, because they showed better inhibitory effect on viral replication and antigen expression in transgenic mice. More importantly, the siRNA markedly inhibited HBV cccDNA amplification.     

Indoleamine 2,3-dioxygenase mediates the antiviral effect of gamma interferon against hepatitis B virus in human hepatocyte-derived cells

Alpha interferon (IFN-α) is an approved medication for chronic hepatitis B. Gamma interferon (IFN-γ) is a key mediator of host innate and adaptive antiviral immunity against hepatitis B virus (HBV) infection in vivo. In an effort to elucidate the antiviral mechanism of these cytokines, 37 IFN-stimulated genes (ISGs), which are highly inducible in hepatocytes, were tested for their ability to inhibit HBV replication upon overexpression in human hepatoma cells. One ISG candidate, indoleamine 2,3-dioxygenase (IDO), an IFN-γ-induced enzyme catalyzing tryptophan degradation, efficiently reduced the level of intracellular HBV DNA without altering the steady-state level of viral RNA. Furthermore, expression of an enzymatically inactive IDO mutant did not inhibit HBV replication, and tryptophan supplementation in culture completely restored HBV replication in IDO-expressing cells, indicating that the antiviral effect elicited by IDO is mediated by tryptophan deprivation. Interestingly, IDO-mediated tryptophan deprivation preferentially inhibited viral protein translation and genome replication but did not significantly alter global cellular protein synthesis. Finally, tryptophan supplementation was able to completely restore HBV replication in IFN-γ- but not IFN-α-treated cells, which strongly argues that IDO is the primary mediator of IFN-γ-elicited antiviral response against HBV in human hepatocyte-derived cells.     

病毒性肝病抗病毒治疗期间新发肝癌7例临床分析

目的:探讨病毒性肝炎肝硬化患者经抗病毒治疗仍发生原发性肝癌的原因。方法:回顾性分析兰州大学第一医院东岗院区肝病中心在2012年10月-2013年6月收治的7例病毒性肝炎肝硬化患者在规范抗病毒治疗期间新发原发性肝癌的临床资料、抗病毒治疗情况。结果:7例患者中有HBV感染6例,HCV感染1例;慢性肝炎2例,肝硬化5例;HBeAg阴性5例;3例合并糖尿病;经抗病毒治疗后病毒载量均处于低度复制或不可测状态。结论:病毒性肝炎肝硬化患者经抗病毒治疗不能完全消除原发性肝癌发生的风险,病毒载量、HBeAg阴性、糖尿病、肝硬化等可能是肝癌发生的危险因素。     

siRNA抑制乙肝病毒的研究进展

乙型肝炎作为一种发病率高、死亡率高的传染性疾病,已严重威胁人类健康,乙肝病毒（hepatitis B virus,HBV）是诱发乙型肝炎的重要病因。目前,最主要的治疗方法是运用抗病毒药物控制病情,但这些药物都不能完全治愈乙型肝炎且复发率高。近年来,RNA干扰技术（RNA interference, RNAi）逐渐成为有效、快速治疗乙型肝炎的新疗法。利用RNA干扰技术体外合成针对HBV基因的siRNA,选择适当的载体将其运送至靶细胞,使HBV基因沉默,从而抑制病毒复制,可有效达到治疗乙肝的效果。本文围绕siRNA沉默HBV基因的设计原理、递送载体、靶向策略、以及治疗效果与应用前景等方面进行了系统综述,为今后siRNA治疗乙肝的临床应用提供参考。     

Sulfamoylbenzamide Derivatives Inhibit the Assembly of Hepatitis B Virus Nucleocapsids

Chronic hepatitis B virus (HBV) infection, a serious public health problem leading to cirrhosis and hepatocellular carcinoma, is currently treated with either pegylated alpha interferon (pegIFN-α) or one of the five nucleos(t)ide analogue viral DNA polymerase inhibitors. However, neither pegIFN-α nor nucleos(t)ide analogues are capable of reliably curing the viral infection. In order to develop novel antiviral drugs against HBV, we established a cell-based screening assay by using an immortalized mouse hepatocyte-derived stable cell line supporting a high level of HBV replication in a tetracycline-inducible manner. Screening of a library consisting of 26,900 small molecules led to the discovery of a series of sulfamoylbenzamide (SBA) derivatives that significantly reduced the amount of cytoplasmic HBV DNA. Structure-activity relationship studies have thus far identified a group of fluorine-substituted SBAs with submicromolar antiviral activity against HBV in human hepatoma cells. Mechanistic analyses reveal that the compounds dose dependently inhibit the formation of pregenomic RNA (pgRNA)-containing nucleocapsids of HBV but not other animal hepadnaviruses, such as woodchuck hepatitis virus (WHV) and duck hepatitis B virus (DHBV). Moreover, heterologous genetic complementation studies of capsid protein, DNA polymerase, and pgRNA between HBV and WHV suggest that HBV capsid protein confers sensitivity to the SBAs. In summary, SBAs represent a novel chemical entity with superior activity and a unique antiviral mechanism and are thus warranted for further development as novel antiviral therapeutics for the treatment of chronic hepatitis B.     

抗乙型肝炎病毒的天然药物研究

如何从丰富的天然生物中筛选具有抗乙型肝炎病毒活性的药物 ,并且研究它们的作用机理 ,寻找特异性强、毒副作用小的药物 ,是我国中药现代化的一个重要研究方向。本文综述了近年来中草药和一些重要的天然化合物抗乙型肝炎病毒的作用机理以及体内外研究和临床应用 ,并提出了在抗乙型肝炎病毒药物筛选中存在的一些问题     

Modeling the transmission dynamics and control of hepatitis B virus in China

Hepatitis B is a potentially life-threatening liver infection caused by the hepatitis B virus (HBV) and is a major global health problem. HBV is the most common serious viral infection and a leading cause of death in mainland China. Around 130 million people in China are carriers of HBV, almost a third of the people infected with HBV worldwide and about 10% of the general population in the country; among them 30 million are chronically infected. Every year, 300,000 people die from HBV-related diseases in China, accounting for 40-50% of HBV-related deaths worldwide. Despite an effective vaccination program for newborn babies since the 1990s, which has reduced chronic HBV infection in children, the incidence of hepatitis B is still increasing in China. We propose a mathematical model to understand the transmission dynamics and prevalence of HBV infection in China. Based on the data reported by the Ministry of Health of China, the model provides an approximate estimate of the basic reproduction number R₀=2.406. This indicates that hepatitis B is endemic in China and is approaching its equilibrium with the current immunization program and control measures. Although China made a great progress in increasing coverage among infants with hepatitis B vaccine, it has a long and hard battle to fight in order to significantly reduce the incidence and eventually eradicate the virus.     

Chronic hepatitis B--who should be treated?

Hepatitis B virus (HBV) can cause both acute and chronic infection and is an important human pathogen, with an estimated 350 million individuals chronically infected worldwide. HBV carriers are at risk for the development of cirrhosis and hepatocellular carcinoma (HCC), and patients with chronic infection require life-long monitoring. Effective hepatitis B antiviral treatment is important given the significant associated global morbidity and mortality from liver-related complications. The goals of treatment are to achieve sustained suppression of HBV replication and remission of liver disease. In the past decade, great progress has been made in the treatment of chronic HBV infection. Interferon alfa, longer-acting pegylated interferon, and nucleos(t)ide analogs such as lamivudine, adefovir dipivoxil, and entecavir are currently available for treatment of HBV infection. Effective treatment decisions require an understanding of the natural history of hepatitis B and the range of treatment options. This review includes criteria for determining when and how to most effectively intervene with antiviral therapy for chronically infected patients.     

乙型肝炎病毒特异性细胞毒性T淋巴细胞在病毒清除过程中的作用

在乙型肝炎病毒(HBV)感染过程中,适应性免疫与病毒的致病和清除密切相关。一般认为,体液免疫产生的抗体可以清除外周循环的病毒颗粒,从而阻止病毒在宿主体内的传播,细胞免疫主要清除被感染细胞中的病毒。HBV特异性的细胞毒性T淋巴细胞(CTL)在抑制HBV复制过程中发挥着重要的作用。CTL在肝内主要通过分泌γ干扰素抑制病毒,同时,当CTL识别HBV抗原后,HBV特异性CTL募集抗原非特异性炎症细胞对肝组织浸润,造成肝细胞的损伤。对CTL抗病毒作用进行深入研究,将为乙型肝炎的治疗开辟新的途径。     

错位双链RNA,丙氧鸟苷和原核细胞DNA促旋酶B对鸭乙肝病毒的抑制作用

人工合成错位双链ＲＮＡ（ａｍｐｌｉｇｅｎ）是一种已知的干扰素诱导剂。单独和／或与其它抗病毒药物联合使用治疗鸭乙型肝炎病毒（ＤＨＢＶ）阳性鸭。这些药物包括丙氧鸟苷（ｇａｎｃｉｃｌｏｖｉｒ）和原核细胞ＤＮＡ促旋酶Ｂ抑制物（ｃｏｕｍｅｒｍｙｃｉｎＡｌ）。单独和／或联合该两种药物时,对鸭血清和肝组织内ＤＨＢＶ均有抑制作用,但以三种药物联合时抑制效果最好。上述下种方案治疗结束后肝内松弛环状ＤＮＡ（ＲＣ）和超螺旋ＤＮＡ（ＳＣ）持续存在,而且不能消除血中鸭乙肝表面抗原（ＤＨＢｓＡｇ）。对治疗的大多数鸭血清干扰素,测定结果表明,ａｍｐｌｉｇｅｎ能诱生鸭干扰素,但其出现时间与抗病毒效果产生没有平行关系。本研究为人慢性乙型肝炎治疗合理使用抗病毒药物和免疫诱导剂提供了参考。     

Tumor necrosis factor-alpha and interleukin-4 in the blood sera of chronic hepatitis patients

The concentration of tumor necrosis factor-alpha (TNF-alpha) and interleukin-4 (IL-4) in the blood sera of chronic hepatitis patients was, on the average, reliably higher than in the control group. A more pronounced increase in the concentration of TNF-alpha in the blood sera was observed in patients with chronic hepatitis of viral etiology in comparison with toxic hepatitis. The pronounced cytokine response of type Th2, manifested by the excessive production of IL-4, was typical for hepatitis B virus and hepatitis C virus infections, but not characteristic of hepatitis D virus infection. The replication activity of hepatotropic viruses induced a powerful cytokine response. In the presence of active virus replication in patients with chronic hepatitis B the levels of both TNF-alpha and IL-4 in their blood sera proved to be reliably higher than in patients with hepatitis B virus in the interactive phase.