Occult HBV infection in HIV‐infected adults and evaluation of pooled NAT for HBV

The study aimed to determine the prevalence of occult hepatitis B virus infection among HIV‐infected persons and to evaluate the use of a pooling strategy to detect occult HBV infection in the setting of HIV infection. Five hundred and two HIV‐positive individuals were tested for HBV, occult HBV and hepatitis C and D with serologic and nucleic acid testing (NAT). We also evaluated a pooled NAT strategy for screening occult HBV infection among the HIV‐positive individuals. The prevalence of HBV infection among HIV‐positive individuals was 32 (6.4%), and occult HBV prevalence was 10%. The pooling HBV NAT had a sensitivity of 66.7% and specificity of 100%, compared to HBV DNA NAT of individual samples. In conclusion, this study found a high prevalence of occult HBV infection among our HIV‐infected population. We also demonstrated that pooled HBV NAT is highly specific, moderately sensitive and cost‐effective. As conventional HBV viral load assays are expensive in resource‐limited settings such as India, pooled HBV DNA NAT might be a good way for detecting occult HBV infection and will reduce HBV‐associated complications.     

Animal models for the study of hepatitis C virus infection and replication

Hepatitis C virus (HCV) hepatitis, initially termed non-A, non-B hepatitis, has become one of the leading causes of cirrhosis and hepatocellular carcinoma worldwide. With the help of animal models, our understanding of the virus has grown substantially from the time of initial discovery. There is a paucity of available animal models for the study of HCV, mainly because of the selective susceptibility limited to humans and primates. Recent work has focused modification of animals to permit HCV entry, replication and transmission. In this review, we highlight the currently available models for the study of HCV including chimpanzees, tupaia, mouse and rat models. Discussion will include methods of model design as well as the advantages and disadvantages of each model. Particular focus is dedicated to knowledge of pathophysiologic mechanisms of HCV infection that have been elucidated through animal studies. Research within animal models is critically important to establish a complete understanding of HCV infection, which will ultimately form the basis for future treatments and prevention of disease.     

Tolerability and efficacy of anti‐HBV nucleos(t)ide analogues in HBV‐DNA‐positive cirrhotic patients with HBV/HCV dual infection

Summary. We evaluated tolerability and virological and clinical impact of anti‐Hepatitis B Virus (HBV) nucleos(t)ide analogues in cirrhotic patients with HBV/Hepatitis C Virus (HCV) coinfection. The virological and clinical course of 24 consecutive HBsAg/HBV‐DNA/anti‐HCV‐positive patients with cirrhosis was compared with that of 24 HBsAg/HBV‐DNA‐positive, anti‐HCV‐negative cirrhotic patients, pair‐matched for age (±5 years), sex, HBeAg/anti‐HBe status and Child‐Pugh class. Patients in both groups were previously untreated with oral antiviral agents at enrolment and were treated for at least 24 months (range 24–54). At the 12th and 18th month of treatment, HBV‐DNA was negative in 21 (87.5%) and 23 (95.8%) patients with hepatitis B and C and in 20 (83.3%) and 22 (91.6%) in patients with isolated HBV; all patients in both groups were HBV‐DNA‐negative at month 24 and at subsequent observations. Treatment was well tolerated by all patients in both groups. At the last observation (for co‐infected patients, median 44 months and range 24–54; for mono‐infected patients, median 40 months and range 24–54), a deterioration in Child class was observed in eight (47%) of 17 patients in patients with both HBV and HCV who were HCV‐RNA‐positive at baseline, but in none of seven HCV‐RNA‐negative patients in the same group, and in one patient (4.2%) in the mono‐infected patients. Reactivation of HCV infection was relatively infrequent (12.5% of cases) and never associated with a clinical deterioration. Treatment with nucleotides in HBsAg/HBV‐DNA/anti‐HCV‐positive patients with cirrhosis showed a favourable virological effect in all cases, but a favourable clinical result only in the HCV‐RNA‐negative at baseline.     

Identified OAS3 gene variants associated with coexistence of HBsAg and anti‐HBs in chronic HBV infection

The underlying mechanism of coexistence of hepatitis B surface antigen (HBsAg) and hepatitis B surface antigen antibody (anti‐HBs) is still controversial. To identify the host genetic factors related to this unusual clinical phenomenon, a two‐stage study was conducted in the Chinese Han population. In the first stage, we performed a case‐control (1:1) age‐ and gender‐matched study of 101 cases with concurrent HBsAg and anti‐HBs and 102 controls with negative HBsAg and positive anti‐HBs using whole exome sequencing. In the second validation stage, we directly sequence the 16 exons on the OAS3 gene in two dependent cohorts of 48 cases and 200 controls. Although, in the first stage, a genome‐wide association study of 58,563 polymorphism variants in 101 cases and 102 controls found no significant loci (P‐value ≤ .05/58563), and neither locus achieved a conservative genome‐wide significance threshold (P‐value ≤ 5e‐08), gene‐based burden analysis showed that OAS3 gene rare variants were associated with the coexistence of HBsAg and anti‐HBs. (P‐value = 4.127e‐06 ≤ 0.05/6994). A total of 16 rare variants were screened out from 21 cases and 3 controls. In the second validation stage, one case with a stop‐gained rare variant was identified. Fisher’s exact test of all 149 cases and 302 controls showed that the rare coding sequence mutations were more frequent in cases vs controls (P‐value = 7.299e‐09, OR = 17.27, 95% CI [5.01‐58.72]). Protein‐coding rare variations on the OAS3 gene are associated with the coexistence of HBsAg and anti‐HBs in patients with chronic HBV infection in Chinese Han population.     

Animal models for the study of hepatitis C virus infection and related liver disease

Hepatitis C virus (HCV) causes liver-related death in more than 300,000 people annually. Treatments for patients with chronic HCV are suboptimal, despite the introduction of directly acting antiviral agents. There is no vaccine that prevents HCV infection. Relevant animal models are important for HCV research and development of drugs and vaccines. Chimpanzees are the best model for studies of HCV infection and related innate and adaptive host immune responses. They can be used in immunogenicity and efficacy studies of HCV vaccines. The only small animal models of robust HCV infection are T- and B- cell deficient mice with human chimeric livers. Although these mice cannot be used in studies of adaptive immunity, they have provided new insights into HCV neutralization, interactions between virus and receptors, innate host responses, and therapeutic approaches. Recent progress in developing genetically humanized mice is exciting, but these models only permit studies of specific steps in the HCV life cycle and have limited or no viral replication.     

The use of nonhuman primate models of HIV infection for the evaluation of antiviral strategies

Several nonhuman primate models are used in HIV/AIDS research. In contrast to natural host models, infection of macaques with virulent simian immunodeficiency virus (SIV) isolates results in a disease (simian AIDS) that closely resembles HIV infection and AIDS. Although there is no perfect animal model, and each of the available models has its limitations, a carefully designed study allows experimental approaches that are not feasible in humans, but that can provide better insights in disease pathogenesis and proof-of-concept of novel intervention strategies. In the early years of the HIV pandemic, nonhuman primate models played a minor role in the development of antiviral strategies. Since then, a better understanding of the disease and the development of better compounds and assays to monitor antiviral effects have increased the usefulness and relevance of these animal models in the preclinical development of HIV vaccines, microbicides, and antiretroviral drugs. Several strategies that were first discovered to have efficacy in nonhuman primate models are now increasingly used in humans. Recent trends include the use of nonhuman primate models to explore strategies that could reduce viral reservoirs and, ultimately, attempt to cure infection. Ongoing comparison of results obtained in nonhuman primate models with those observed in human studies will lead to further validation and improvement of these animal models so they can continue to advance our scientific knowledge and guide clinical trials.     

Animal models used for the evaluation of antiretroviral therapies

Several animal models for the study of HIV/AIDS have been established and characterized and have been widely used to study the pathogenesis of HIV/AIDS as well as vaccine development. The purpose of this study was to review the literature and identify the animal models most frequently used for the evaluation of drugs, drug combinations, plant extracts and drug-plant combinations. Four of these animal models were evaluated namely the SIV model due to its similarities in pathogenesis of disease to humans, the FIV and the LP-BM5 model due to wide availability and the SCID murine model that combines components of both systems. The pathogenesis of disease in each model, application in the evaluation of drugs, drug combinations and plant extracts as well as the inherent advantages and disadvantages of each model are discussed. The LP-BM5 murine AIDS (MAIDS) model with its in vitro equivalent was identified as the animal model, although not identical to HIV/AIDS, most suitable for the rapid and cost effective initial screening of drugs, drug combinations, plant extracts and drug-plant combinations.     

多重耐药HBV感染特点及挽救治疗策略

多重耐药HBV感染的治疗是临床面临的一个难题。多重耐药的发生主要与病毒因素、宿主因素和药物因素等相关。严格评估抗病毒治疗指征,初治选择高耐药基因屏障的抗病毒药物,避免以低耐药基因屏障药物起始的单药序贯治疗等措施能够降低多重耐药HBV株产生的风险。对于已发生耐药与多重耐药HBV感染的患者,应尽早开始挽救性治疗。有多项研究提示恩替卡韦与替诺福韦酯联合是针对难治性多重耐药HBV感染的更加有效、安全的挽救性治疗方案。研究开发多靶点作用的新型抗病毒药物是治疗多重耐药HBV感染的新途径。     

乙型肝炎病毒感染模型研究新进展

病毒性肝炎抗病毒药物的开发和评价中的重要环节之一就是建立一种方便有效的体内外模型。现就乙型肝炎的感染模型新进展作一简要综述。 一、体外模型 乙型肝炎病毒(hepatitis B virus,HBV)感染有高度的种属和组织特异性,它只感染人和类人猿。其原因是病毒黏附以及病毒DNA转录及复制对细胞有严格的要求。体外培养的     

Animal models for the study of hepatic fibrosis

Animal models are being used for several decades to study fibrogenesis and to evaluate the anti-fibrotic potential of therapies and strategies. Although immensely valuable for our understanding of pathophysiological processes, they remain models and none of them reproduces a human disease. Each model (meaning stimulus, design, strain and species) displays specific characteristics in the nature of the pathogenesis, the topography and the evolution of fibrosis. We review here the most used as well as some newly described but potentially interesting models including models for studying biliary, immune, alcohol-induced, NASH-associated and viral fibrosis and provide insight on underlying disease processes and practical details. We attempted to delineate the benefits, advantages, limitations and drawbacks of those models. We also report the new opportunities provided by genetically engineered mice for tracking and manipulating cells that participate to fibrosis. Finally, we emphasize the importance of adapting study design to the question addressed.     

Animal models for the study of portal hypertension

Animal models allow detailed study of the hemodynamic alterations in portal hypertension syndrome and of the molecular mechanisms involved in the abnormalities in splenic and systemic circulation associated with this syndrome. Models of prehepatic portal hypertension can be used to study alterations in the splenic circulation and the physiopathology of hyperdynamic circulation. Moreover, models of cirrhosis allow the alterations in intrahepatic microcirculation that lead to increased resistance to portal flow to be studied. The present review summarizes currently available animal models of portal hypertension and analyzes their relative utility in investigating the distinct disorders associated with this entity. The criteria for the choice of a particular model, depending on the specific objectives of the study, are also discussed.     

Gender‐related issues in the pharmacology of new anti‐obesity drugs

Four new medicines—liraglutide, lorcaserin, bupropion/naltrexone, and phentermine/topiramate—have been recently added to the pharmacological arsenal for obesity treatment and could represent important tools to manage this epidemic disease. To achieve satisfactory anti‐obesity goals, the use of these new medicines should be optimized and tailored to specific patient subpopulations also by applying dose adjustments if needed. In the present review, we posit that gender could be among the factors influencing the activity of the new obesity drugs both because of pharmacokinetic and pharmacodynamic factors. Although evidence from premarketing clinical studies suggested that no dose adjustment by gender is necessary for any of these new medicines, these studies were not specifically designed to identify gender‐related differences. This observation, together with the strong theoretical background supporting the hypothesis of a gender‐dimorphic response, strongly call upon an urgent need of new real‐life data on gender‐related difference in the pharmacology of these new obesity drugs.     

Animal models of dengue virus infection

The development of animal models of dengue virus (DENV) infection and disease has been challenging, as epidemic DENV does not naturally infect non-human species. Non-human primates (NHPs) can sustain viral replication in relevant cell types and develop a robust immune response, but they do not develop overt disease. In contrast, certain immunodeficient mouse models infected with mouse-adapted DENV strains show signs of severe disease similar to the 'vascular-leak' syndrome seen in severe dengue in humans. Humanized mouse models can sustain DENV replication and show some signs of disease, but further development is needed to validate the immune response. Classically, immunocompetent mice infected with DENV do not manifest disease or else develop paralysis when inoculated intracranially; however, a new model using high doses of DENV has recently been shown to develop hemorrhagic signs after infection. Overall, each model has its advantages and disadvantages and is differentially suited for studies of dengue pathogenesis and immunopathogenesis and/or pre-clinical testing of antiviral drugs and vaccines.     

HBV动物模型研究进展

HBV感染动物模型是研究HBV致病机制、筛选新型有效抗HBV药物和治疗方法的重要工具,然而HBV感染具有高度组织特异性以及种属特异性,这给HBV感染动物模型的建立带来了困难。近年来,随着分子生物学、实验动物学、病毒学及免疫学等相关学科技术的进步,HBV感染或复制动物模型取得了明显进展。目前应用于HBV(包括与HBV具有相似特性的动物肝炎病毒)研究的动物模型主要包括黑猩猩、树鼩、土拨鼠及鸭HBV感染模型,HBV转基因小鼠、高压水动力注射介导的小鼠HBV复制模型和重组腺相关病毒载体介导的小鼠HBV复制模型,以及人源化人-鼠嵌合肝脏HBV感染模型,此外,钠离子-牛磺胆酸共转运蛋白转基因小鼠感染模型是近年的研究热点。本文就上述HBV动物模型的研究进展进行综述。