Hepatitis B virus: the "metabolovirus" highjacks cholesterol and bile acid metabolism

Serum ApoB/ApoA1 ratio in patients with CHB and the occurrence of HBV related cirrhosis and HBV related hepatocellular carcinoma

Clinical research has suggested that chronic HBV infection exerts a certain effect on the occurrence of cardiovascular disease by regulating cholesterol metabolism in liver cells. High serum apolipoprotein B/apolipoprotein A1 (ApoB/ApoA1) ratio plays a certain role in the above regulation, and it serves as a risk factor for cardiovascular disease. However, whether the ApoB/ApoA1 ratio is correlated with chronic HBV infection and its disease progression remains unclear. In accordance with the inclusion and exclusion criteria, all 378 participants administrated at Renmin Hospital of Wuhan University from March 2021 to March 2022, fell into Healthy Control (HC) group (50 participants), Hepatocellular carcinoma (HCC) group (107 patients), liver cirrhosis (LC) group (64 patients), chronic hepatitis B (CHB) group (62 patients), chronic hepatitis C (CHC) group (46 patients) and Hepatitis E Virus (HEV) group (49 patients). Serum ApoA1 and ApoB concentrations were measured at admission, and the ApoB/ApoA1 ratio was determined. The levels of laboratory parameters in the respective group were compared and ApoB/ApoA1 ratios in HCC patients and LC patients with different severity were further analyzed. ROC curves were plotted to analyze the early diagnostic ability of ApoB/ApoA1 ratio for HBV-associated HCC. Logistic regression and restricted cubic spline analysis were used to explore the correlation between ApoB/ApoA1 ratio and LC and HCC risk. A comparison was drawn in terms of ApoB/ApoA1 ratio between the groups, and the result was expressed in descending sequence: HEV group > CHB group > LC group > HCC group > CHC group > HC group, early-stage HCC < middle-stage HCC < advanced-stage HCC, Class A LC < Class B LC < Class C LC. Serum ApoB/ApoA1 ratio combined diagnosis with AFP exhibited the capability of increasing the detection efficacy and specificity of AFP for HCC and AFP-negative HCC. The incidence of LC and HCC in the respective logistic regression model showed a negative correlation with the serum ApoB/ApoA1 ratio in CHB patients (P < 0.05). After all confounding factors covered in this study were regulated, the result of the restricted cubic spline analysis suggested that in a certain range, serum ApoB/ApoA1 ratio showed an inverse correlation with the prevalence of LC or HCC in CHB patients. Serum ApoB/ApoA1 ratio in CHB patients may be conducive to identifying high-risk patients for HCC or LC, such that LC and HCC can be early diagnosed and treated.

Human gut microbiota from hepatitis B virus-infected individuals is associated with reduced triglyceride level in mice: faecal transplantation study

BACKGROUND AND AIMS

Chronic hepatitis B virus (HBV) infection is associated with a reduced risk of dyslipidaemia. Using a human faecal microbiota transplantation (FMT), we compared changes in gut microbiota and lipid profiles in mice transplanted with human faeces from HBV-infected and non-infected individuals.

APPROACH AND RESULTS

A total of 19 mice received human FMT from four HBV-infected individuals and were categorised into the HBV-positive mice group, while 20 mice received FMT from four HBV-non-infected individuals into the HBV-negative one. In the analysis of gut microbiota in FMT mice, we observed a robust increase in alpha diversity and abundance of Akkermansia muciniphila in HBV-positive mice, compared to that in HBV-negative. Functional inference analysis revealed that the pathways involved in glycerolipid metabolism were more enriched in HBV-positive mice. At 5 weeks of FMT, the reduced triglyceride (TG) level was predominantly observed in HBV-positive mice.

CONCLUSIONS

Altered gut microbiota accompanied by HBV infection was associated with a robust increase in alpha diversity and butyrate producers, which resulted in a reduced level of TG at 5 weeks post-FMT. This indicates that the reduced risk of dyslipidaemia in chronic HBV infection may be due to the altered gut microbiota accompanied by HBV infection.

Cholesterol: A friend to viruses

Cholesterol is a key life-sustaining molecule which regulates membrane fluidity and serves as a signaling mediator. Cholesterol homeostasis is closely related to various pathological conditions including tumor, obesity, atherosclerosis, Alzheimer's disease and viral infection. Viral infection disrupts host cholesterol homeostasis, facilitating their own survival. Meanwhile, the host cells strive to reduce cholesterol accessibility to limit viral infection. This review focuses on the regulation of cholesterol metabolism and the role of cholesterol in viral infection, specifically providing an overview of cholesterol as a friend to promote viral entry, replication, assembly, release and immune evasion, which might inspire valuable thinking for pathogenesis and intervention of viral infection.

Letter: association of circulating bile acid concentrations and non-alcoholic fatty liver disease

This article is linked to Rivera–Andrade et al papers. To view these articles, visit https://doi.org/10.1111/apt.16948 and https://doi.org/10.1111/apt.17059

Viral Hepatitis, Cholesterol Metabolism, and Cholesterol-Lowering Natural Compounds

Hepatitis is defined as inflammation of the liver; it can be acute or chronic. In chronic cases, the prolonged inflammation gradually damages the liver, resulting in liver fibrosis, cirrhosis, and sometimes liver failure or cancer. Hepatitis is often caused by viral infections. The most common causes of viral hepatitis are the five hepatitis viruses—hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), and hepatitis E virus (HEV). While HAV and HEV rarely (or do not) cause chronic hepatitis, a considerable proportion of acute hepatitis cases caused by HBV (sometimes co-infected with HDV) and HCV infections become chronic. Thus, many medical researchers have focused on the treatment of HBV and HCV. It has been documented that host lipid metabolism, particularly cholesterol metabolism, is required for the hepatitis viral infection and life cycle. Thus, manipulating host cholesterol metabolism-related genes and proteins is a strategy used in fighting the viral infections. Efforts have been made to evaluate the efficacy of cholesterol-lowering drugs, particularly 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, in the treatment of hepatitis viral infections; promising results have been obtained. This review provides information on the relationships between hepatitis viruses and host cholesterol metabolism/homeostasis, as well as the discovery/development of cholesterol-lowering natural phytochemicals that could potentially be applied in the treatment of viral hepatitis.

Emerging Insights on the Diverse Roles of Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) in Chronic Liver Diseases: Cholesterol Metabolism and Beyond

Chronic liver diseases are commonly associated with dysregulated cholesterol metabolism. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a serine protease of the proprotein convertase family that is mainly synthetized and secreted by the liver, and represents one of the key regulators of circulating low-density lipoprotein (LDL) cholesterol levels. Its ability to bind and induce LDL-receptor degradation, in particular in the liver, increases circulating LDL-cholesterol levels in the blood. Hence, inhibition of PCSK9 has become a very potent tool for the treatment of hypercholesterolemia. Besides PCSK9 limiting entry of LDL-derived cholesterol, affecting multiple cholesterol-related functions in cells, more recent studies have associated PCSK9 with various other cellular processes, including inflammation, fatty acid metabolism, cancerogenesis and visceral adiposity. It is increasingly becoming evident that additional roles for PCSK9 beyond cholesterol homeostasis are crucial for liver physiology in health and disease, often contributing to pathophysiology. This review will summarize studies analyzing circulating and hepatic PCSK9 levels in patients with chronic liver diseases. The factors affecting PCSK9 levels in the circulation and in hepatocytes, clinically relevant studies and the pathophysiological role of PCSK9 in chronic liver injury are discussed.

The evaluation of serum lipid profile in chronic Hepatitis B patients at a Tertiary Care Centre in Western India: A cross-sectional study

Introduction

Hepatitis B virus (HBV) is known as a metabolovirus due to its impact on lipid and glucose metabolism in the liver. Previous literature showed a trend of hypolipidemia and reduced risk of metabolic syndrome in hepatitis B surface antigen-positive patients. However, data from the Indian population are lacking. We evaluate the relation of lipid profile with HBV infection and severity of liver disease.

Materials and Methods

This was an observational cross-sectional study in which 50 patients with chronic hepatitis B and 43 anthropometrically matched seronegative controls were enrolled. Demographical, clinical, and laboratory data including lipid profile (high-density lipoprotein [HDL], low-density lipoprotein [LDL], triglycerides, and total cholesterol [TC]) were collected. Seropositive patients were categorized based on prognostic models (model for end-stage liver disease [MELD] and Child-Pugh score) for further analysis.

Results

Our study revealed significant low levels of serum TC, HDL, and LDL cholesterol in hepatitis B patients compared to seronegative controls (133.06 vs. 162.39, 35.56 vs. 43.65, and 76.62 vs. 99.95 mg/dl respectively, P < 0.05). The patients with high MELD and Child-Pugh score were associated with hypolipidemia. Significant low levels of LDL and TC were observed in Child-Pugh class C in comparison to class A (94.8 vs. 149.2 and 50.6 vs. 87.9 mg/dl respectively, P < 0.05).

Conclusions

A significant reduction in various lipid parameters was seen with chronic hepatitis B. Furthermore, prognostic score (high MELD and Child-Pugh score) were associated with hypolipidemia.

Advanced Liver Fibrosis Is Associated with Necroinflammatory Grade but Not Hepatic Steatosis in Chronic Hepatitis B Patients

BACKGROUND AND AIMS

Patients with chronic hepatitis B (CHB) are at an increased risk of disease progression. The influence of hepatic steatosis (HS) to liver fibrosis was controversial. We aim to investigate the association between HS and liver fibrosis and explore the predicting factors for advanced fibrosis.

METHODS

CHB patients undergoing liver biopsy with complete assessments of HS, necroinflammation grade [histological activity index (HAI) score], and fibrosis stage were retrospectively recruited. Logistic regression analysis was performed to determine the factors associated with advanced liver fibrosis.

RESULTS

In this cohort of 672 patients, 342 (50.9%) had HS and 267 (39.4%) were of advanced liver fibrosis. Age [odds ratio (OR) 1.026, 95% confidence interval (CI) 1.007-1.046, p = 0.008], body mass index (BMI, OR 1.091, 95% CI 1.026-1.159, p = 0.005), genotype (C vs. B) (OR 2.790, 95% CI 1.847-4.214, p < 0.001), platelet (OR 0.986, 95% CI 0.982-0.991, p < 0.001), and HAI score (OR 1.197, 95% CI 1.114-1.285, p < 0.001) were independent factors for advanced liver fibrosis in multivariate logistic regression analysis. HAI score was also a significantly associated factor for significant liver fibrosis in non-cirrhotic subpopulation (OR 1.578, 95% CI 1.375-1.810, p < 0.001). HS was not related to advanced/significant liver fibrosis in overall/non-cirrhotic population (p > 0.05).

CONCLUSIONS

Significant or advanced liver fibrosis is associated with grade of necroinflammation but not with HS in CHB patients.

Hepatic steatosis and development of type 2 diabetes: Impact of chronic hepatitis B and viral specific factors

BACKGROUND

Chronic hepatitis B (CHB) was associated with a lower prevalence of nonalcoholic fatty liver disease (NAFLD). The impact of CHB on the link between NAFLD and type 2 diabetes (T2D) and related virological implications remain unclear.

METHODS

We recruited 2255 middle-to older-aged individuals who were examined serially for hepatic steatosis by ultrasonography and blood biochemistry as part of a population-based hepatocellular-carcinoma cohort study. In CHB patients, hepatitis B surface antigen (HBsAg) seroclearance and variation in viral load trajectory were also evaluated.

RESULTS

During the average follow-up of 6 years, 168 participants developed T2D. CHB, as compared with uninfected subjects, was associated with lower risks for both new development and persistence of hepatic steatosis. Furthermore, the risk of steatosis decreased with higher levels of past viral load trajectories (p for trend = 0.0002). However, concomitant steatosis at baseline in CHB patients was still significantly associated with a 1.98-fold increased risk for T2D after multivariate adjustment including age, impaired fasting glucose, cirrhosis, and time-varying body mass index, although CHB reduced the propensity of hepatic steatosis to develop diabetes, especially for patients with high levels of past viral-load trajectory. In CHB, the functional cure of HBV infection, as indicated by HBsAg seroclearance, was associated with a 1.41-fold (95% CI 1.12-1.79) increased risk of steatosis. In addition, the increased risk for progressive impairment of glucose metabolism due to steatosis was especially prominent after HBsAg seroclearance.

CONCLUSION

The data showed that HBV interferes with fatty liver disease and modulates its related T2D risk, offering additional insight into the interplay between NAFLD and CHB.

Relationship between gut microbiome diversity and hepatitis B viral load in patients with chronic hepatitis B

Background

Hepatitis B virus (HBV) infection is associated with a reduced risk of developing dyslipidemia and non-alcoholic fatty liver diseases. Given that the gut microbiota plays a significant role in cholesterol metabolism, we compared the differences in gut microbial diversity and composition between HBV-infected and uninfected subjects.

Results

A prospective case–control study was designed comprising healthy controls (group A) and HBV-infected individuals (group B) in a 1:1 ratio (57 participants each; total = 114). The patients in group B were divided into two subgroups according to their HBV DNA loads: B1 < 2000 IU/mL (N = 40) and B2 ≥ 2000 IU/mL (N = 17). In a pairwise comparison of HBV-infected individuals and controls, higher alpha diversity was noted in group B, and the difference was significant only in patients in group B1. Alloprevotella and Eubacterium coprostanoligenes were predominant in group B1 compared to the control, whereas the abundance of Bacteroides fragilis and Prevotella 2 was lower.

Conclusions

The gut microbiome in HBV-infected individuals with a low viral load is highly diverse and is dominated by specific taxa involved in fatty acid and lipid metabolism. To our knowledge, this is the first demonstration of a correlation between the presence of certain bacterial taxa and chronic HBV infection depending on the load of HBV DNA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13099-021-00461-1.

mTOR Signaling: The Interface Linking Cellular Metabolism and Hepatitis B Virus Replication

Mammalian target of rapamycin (mTOR) is a conserved Ser/Thr kinase that includes mTOR complex (mTORC) 1 and mTORC2. The mTOR pathway is activated in viral hepatitis, including hepatitis B virus (HBV) infection-induced hepatitis. Currently, chronic HBV infection remains one of the most serious public health issues worldwide. The unavailability of effective therapeutic strategies for HBV suggests that clarification of the pathogenesis of HBV infection is urgently required. Increasing evidence has shown that HBV infection can activate the mTOR pathway, indicating that HBV utilizes or hijacks the mTOR pathway to benefit its own replication. Therefore, the mTOR signaling pathway might be a crucial target for controlling HBV infection. Here, we summarize and discuss the latest findings from model biology research regarding the interaction between the mTOR signaling pathway and HBV replication.

Liver Lipids of Patients with Hepatitis B and C and Associated Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) still remains a difficult to cure malignancy. In recent years, the focus has shifted to lipid metabolism for the treatment of HCC. Very little is known about hepatitis B virus (HBV) and C virus (HCV)-related hepatic lipid disturbances in non-malignant and cancer tissues. The present study showed that triacylglycerol and cholesterol concentrations were similar in tumor adjacent HBV and HCV liver, and were not induced in the HCC tissues. Higher levels of free cholesterol, polyunsaturated phospholipids and diacylglycerol species were noted in non-tumorous HBV compared to HCV liver. Moreover, polyunsaturated phospholipids and diacylglycerols, and ceramides declined in tumors of HBV infected patients. All of these lipids remained unchanged in HCV-related HCC. In HCV tumors, polyunsaturated phosphatidylinositol levels were even induced. There were no associations of these lipid classes in non-tumor tissues with hepatic inflammation and fibrosis scores. Moreover, these lipids did not correlate with tumor grade or T-stage in HCC tissues. Lipid reprogramming of the three analysed HBV/HCV related tumors mostly resembled HBV-HCC. Indeed, lipid composition of non-tumorous HCV tissue, HCV tumors, HBV tumors and HBV/HCV tumors was highly similar. The tumor suppressor protein p53 regulates lipid metabolism. The p53 and p53S392 protein levels were induced in the tumors of HBV, HCV and double infected patients, and this was significant in HBV infection. Negative correlation of tumor p53 protein with free cholesterol indicates a role of p53 in cholesterol metabolism. In summary, the current study suggests that therapeutic strategies to target lipid metabolism in chronic viral hepatitis and associated cancers have to consider disease etiology.

S6K1 inhibits HBV replication through inhibiting AMPK-ULK1 pathway and disrupting acetylation modification of H3K27

AIMS

To investigated the effect of S6K1 on the replication and transcription of HBV DNA using multiple cell models.

MAIN METHODS

The pgRNA, total HBV RNA and HBV DNA level were detected by Real-time PCR. The HBcAg expression by Western blot and the activity of four HBV promoters, such as preS1, preS2/S, core, and X promoters by using dual luciferase reporter assay. Moreover, we determined S6K1 interacted with HBcAg in both cytoplasm and nucleus through Immunofluorescence, co-immunoprecipitation (CoIP) and Western blot.

KEY FINDINGS

S6K1 inhibited HBV DNA replication and cccDNA-dependent transcription in HBV-expressing stable cell lines. The mechanistic study revealed that S6K1 suppressed HBV DNA replication by inhibiting AMPK-ULK1 autophagy pathway, and the nuclear S6K1 suppressed HBV cccDNA-dependent transcription by inhibiting the acetylation modification of H3K27. In addition, HBV capsid protein (HBcAg) suppressed the phosphorylation level of S6K1Thr389 by interacting with S6K1, indicating a viral antagonism of S6K1-mediated antiviral mechanism.

SIGNIFICANCE

The p70 ribosomal S6 kinase (S6K1) is a serine/threonine protein kinase, and it plays a significant role in different cellular processes. It has been previously reported that S6K1 affects hepatitis B virus (HBV) replication but the underlying mechanism remains unclear. In this study, our data suggested that the activation of S6K1 restricts HBV replication through inhibiting AMPK-ULK1 autophagy pathway and H3K27 acetylation. These findings indicated that S6K1 might be a potential therapeutic target for HBV infection.

Differential expression profile of long noncoding RNAs in chronic HBV infection: New insights into pathogenesis

Increasing studies have revealed that long noncoding RNAs (lncRNAs) might play vital roles in the development and progression of various diseases including viral infectious diseases. However, the expression and biological functions of lncRNAs in chronic hepatitis B virus (HBV) infection remain largely unknown. Therefore, lncRNA microarray was performed to analyze the lncRNAs' and messenger RNAs' (mRNAs) expression profiles in liver tissues from patients with chronic HBV infection. Subsequently, a comprehensive bioinformatics analysis was conducted to investigate the potential functions of the differentially expressed genes. As a result, a total of 203 differentially expressed lncRNAs and 180 mRNAs were identified in chronic HBV infection. The expressions of five differentially expressed lncRNAs were further validated using quantitative real-time polymerase chain reaction. Gene ontology, pathway analysis, and gene set enrichment analysis revealed that differentially expressed lncRNAs might be mainly be involved in cytokine-cytokine receptor interaction and varied biotransformation processes, including fatty acid metabolism, amino acid metabolism, carbon metabolism, and drug metabolism. Additionally, coexpression networks between differentially expressed lncRNAs and mRNAs were constructed to reveal the hub regulator and analyze the functional pathways. This study provided an overview of lncRNA and mRNA expression in liver tissues from patients with chronic HBV infection. These differentially expressed lncRNAs might play crucial roles in the pathogenesis and progression of chronic HBV infection, which deserve further investigation.

The impact of hepatitis B virus infection status on the prevalence of nonalcoholic fatty liver disease: A population-based study

BACKGROUND

We aimed to explore the impact of hepatitis B virus (HBV) infection on the prevalence of nonalcoholic fatty liver disease (NAFLD) based on clinical big data.

METHODS

Data were collected from the health examination center of the First Affiliated Hospital of Fujian Medical University. Univariate and multivariate analysis were applied to investigate the relationship between HBV and NAFLD.

RESULTS

A total of 14 452 patients were included, with an average age of 43.84 ± 13.03 years. Cases of HBV current infection, past infection, and noninfection were 21 102 110 (14.6%), 90 039 003 (62.3%), and 33 393 339 (23.1%), respectively. The prevalence of NAFLD was significantly lower in the current infection group (29.9%) than in the past infection group (35.8%) and noninfection group (31.9%) (P < .001). After adjusting for age, the prevalence of NAFLD in the current infection group remained the lowest across all of the age groups. Multivariate analysis showed that current infection was at a lower risk of NAFLD (odds ratio [OR] = 0.717, 95% CI: 0.608-0.846), whereas past infection had no effect on NAFLD.

CONCLUSIONS

Current HBV infection may lower the risk of NAFLD. This effect becomes insignificant when the patient is no longer infected.

Risk factors associated with hepatic osteopathy in HBV related cirrhosis measured by liver stiffness: An Observational study

To investigate the differences in bone mineral density between patients with liver cirrhosis and healthy control, and to analyze the risk factors of hepatic osteoporosis in patients with HBV related liver cirrhosis.A total of 189 patients with liver cirrhosis and 207 health controls were enrolled. The bone mineral density of lumbar spine and femoral neck was examined by dual energy X-ray absorptiometry. -2.0 <T value <-1.0 defined as osteopenia, T value ≤-2.0 defined as osteoporosis.Bone mineral density in the cirrhotic group was significantly lower than that in the control group (lumbar: 1.02 ± 0.16 vs 1.08 ± 0.13, P < .001; femoral neck: 0.86 ± 0.14 vs 0.91 ± 0.14, P < .001). Both 2 groups showed a tendency that decrease bone density correlated with age and decrease body mass index (BMI). Multivariate correlation analysis showed that women (OR = 6.931, P = .002), age (OR = 1.096, P < .001), low BMI (OR = 0.874, P = .037), and high liver stiffness value (OR = 1.125, P = .046) were independent risk factors for osteopenia and low body weight (OR = 0.934, P = .006) and high liver stiffness value (OR = 1.246, P = .034) were independent risk factors for osteoporosis.Our study shows that bone mineral density in patients with liver cirrhosis decreased significantly, especially in the elderly and low BMI patient. For HBV-related cirrhosis with risk factors, a regular bone density screening should be given, and timely intervention should be taken into consideration.

Chronic hepatitis B virus infection and risk of dyslipidaemia: A cohort study

Hepatitis B virus (HBV) infection has been associated with a decreased prevalence of dyslipidaemia in cross-sectional studies, but cohort studies are limited. We investigated the longitudinal effects of chronic HBV infection on the development of dyslipidaemia. We performed a cohort study of 62 287 non-cirrhotic adult men and women free of dyslipidaemia who underwent serologic testing for hepatitis B surface antigen (HBsAg) and were followed annually or biennially for an average of 4.46 years. A parametric proportional hazard model was used to estimate the adjusted hazard ratio with 95% confidence interval (CI) for incident dyslipidaemia according to HBsAg seropositivity status. We identified 12 331 incident cases of hypercholesterolaemia during 278 004.4 person-years of follow-up (incident rate 44.4 per 1000 person-years). In models adjusted for age, sex, body mass index, year of screening exam, smoking status, alcohol intake, regular exercise and education level, the adjusted hazard ratios (95% CIs) for incident hypercholesterolaemia, high LDL cholesterolaemia; hypertriglyceridaemia, high non-HDL cholesterolaemia and low HDL cholesterolaemia comparing HBsAg-positive to HBsAg-negative participants was 0.71 (0.64-0.79), 0.83 (0.78-0.89), 0.61 (0.54-0.70), 0.69 (0.63-0.75) and 1.10 (0.98-1.24), respectively. An inverse association between HBsAg positivity and incident high apolipoprotein B were also identified, with a corresponding a hazard ratio of 0.63 (0.55-0.72). In a large cohort of apparently healthy Korean adults, HBsAg seropositivity was associated with lower risk of development of dyslipidaemia, suggesting a role of HBV infection in lipid metabolism.

The Role of Promyelocytic Leukemia Protein in Steatosis-Associated Hepatic Tumors Related to Chronic Hepatitis B virus Infection

The persistence of hepatitis B surface antigen (HBsAg) is a risk factor for the development of steatosis-associated tumors in chronic hepatitis B virus (HBV) infection, yet little is known about the metabolic link with this factor. We correlated HBV-related pathogenesis in genetically engineered mice and human carriers with metabolic proteomics and lipogenic gene expression profiles. The immunohistochemistry showed that the promyelocytic leukemia protein (PML, a tumor suppressor involved in genome maintenance and fatty acid oxidation), being inversely influenced by the dynamic HBsAg levels from acute phase to seroclearance, appeared as a lipo-metabolic switch linking HBsAg-induced steatosis (lipogenesis) to HBsAg-lost fat-burning hepatocarcinogenesis (lipolysis). Knockdown of PML in HBsAg-transgenic mice predisposed to obesity and drove early steatosis-specific liver tumorigenesis. Proteome analysis revealed that the signaling pathways corresponding to energy metabolism and its regulators were frequently altered by suppression or depletion of PML in the HBsAg-transgenic mice, mainly including oxidative phosphorylation and fatty acid metabolism. Expression profiling further identified upregulation of stearoyl-CoA desaturase 1 (Scd1) and epigenetic methylation of NDUFA13 in the mitochondrial respiratory chain and the cell cycle inhibitor CDKN1c in concordance to the increased severity of lipodystrophy and neoplasia in the livers of HBsAg-transgenic mice with PML insufficiency. The defect in lipolysis in PML-deficient HBsAg-transgenic mice made the HBsAg-induced adipose-like liver tumors vulnerable to synthetic lethality from toxic saturated fat accumulation with a Scd1 inhibitor. Our findings provide mechanistic insights into the evolution of steatosis-associated hepatic tumors driven by reciprocal interactions of HBsAg and PML, and a potential utility of lipid metabolic reprogramming as a treatment target.

Pathways of topological rank analysis (PoTRA): a novel method to detect pathways involved in hepatocellular carcinoma

Complex diseases such as cancer are usually the result of a combination of environmental factors and one or several biological pathways consisting of sets of genes. Each biological pathway exerts its function by delivering signaling through the gene network. Theoretically, a pathway is supposed to have a robust topological structure under normal physiological conditions. However, the pathway's topological structure could be altered under some pathological condition. It is well known that a normal biological network includes a small number of well-connected hub nodes and a large number of nodes that are non-hubs. In addition, it is reported that the loss of connectivity is a common topological trait of cancer networks, which is an assumption of our method. Hence, from normal to cancer, the process of the network losing connectivity might be the process of disrupting the structure of the network, namely, the number of hub genes might be altered in cancer compared to that in normal or the distribution of topological ranks of genes might be altered. Based on this, we propose a new PageRank-based method called Pathways of Topological Rank Analysis (PoTRA) to detect pathways involved in cancer. We use PageRank to measure the relative topological ranks of genes in each biological pathway, then select hub genes for each pathway, and use Fisher's exact test to test if the number of hub genes in each pathway is altered from normal to cancer. Alternatively, if the distribution of topological ranks of gene in a pathway is altered between normal and cancer, this pathway might also be involved in cancer. Hence, we use the Kolmogorov-Smirnov test to detect pathways that have an altered distribution of topological ranks of genes between two phenotypes. We apply PoTRA to study hepatocellular carcinoma (HCC) and several subtypes of HCC. Very interestingly, we discover that all significant pathways in HCC are cancer-associated generally, while several significant pathways in subtypes of HCC are HCC subtype-associated specifically. In conclusion, PoTRA is a new approach to explore and discover pathways involved in cancer. PoTRA can be used as a complement to other existing methods to broaden our understanding of the biological mechanisms behind cancer at the system-level.

Risk factors associated with liver steatosis and fibrosis in chronic hepatitis B patient with component of metabolic syndrome

Background

We investigated whether metabolic syndrome exacerbated the risk of liver fibrosis among chronic hepatitis B patients and risk factors associated with liver steatosis and fibrosis in chronic hepatitis B patients with components of metabolic syndrome.

Methods

This study included 1236 chronic hepatitis B patients with at least one component of metabolic syndrome. The controlled attenuation parameter and liver stiffness, patient information and relevant laboratory data were recorded.

Results

Controlled attenuation parameter was increased progressively with the number of metabolic syndrome components (p < 0.001). Multivariate analysis indicated younger age, high gamma-glutamyltransferase level, high waist-hip ratio, and high body mass index were independent risk factors associated with nonalcoholic fatty liver disease among chronic hepatitis B patients with metabolic syndrome. In the fibrosis and non-fibrosis groups, most of blood lipid was relatively lower in fibrosis group. An increased proportion of chronic hepatitis B patients with liver fibrosis was found concomitant with an increasing number of components of metabolic syndrome. Male gender, older age, smoking, aspartate aminotransferase levels, high body mass index, and low platelet level were identified as independent risk factors associated with liver fibrosis.

Conclusions

For chronic hepatitis B patients with coexisting components of metabolic syndrome, stratification by independent risk factors for nonalcoholic fatty liver disease and fibrosis can help with management of their disease.

Nonalcoholic fatty liver disease and the ongoing role of liver biopsy evaluation

Nonalcoholic fatty liver disease (NAFLD) is one of the most common underlying causes of chronically elevated liver tests and liver disease in adults and children worldwide and may be strongly suspected if not diagnosed by ever evolving and available serologic and imaging‐based noninvasive tests. However, the definitive diagnosis of the most progressive form of NAFLD, nonalcoholic steatohepatitis, and the identification of fibrosis stage still require liver biopsy evaluation as noninvasive testing has not replaced some of the specifics or the totality of information obtainable from liver biopsy. In this review, both the role and value of a liver biopsy evaluation in NAFLD/ nonalcoholic steatohepatitis are examined from publications related to a selected variety of settings. Details of the most commonly used semiquantitative methods of analysis are discussed, and some useful potential pitfalls for differential diagnostic consideration in liver biopsy interpretation are given. (Hepatology Communications 2017;1:370–378)

Hepatitis B virus infection and decreased risk of nonalcoholic fatty liver disease: A cohort study

The presence of an association between chronic hepatitis B virus (HBV) infection and fatty liver is controversial. We examined the association between HBV infection and the development of nonalcoholic fatty liver disease (NAFLD). We conducted a cohort study of 83,339 participants without NAFLD at baseline who underwent serologic testing for hepatitis B surface antigen (HBsAg) between 2002 and 2006 and were followed annually or biennially until December 2014. NAFLD was defined as the presence of ultrasonographic fatty liver in the absence of excessive alcohol use or other identifiable causes. We used a parametric Cox model to estimate adjusted hazard ratios with 95% confidence intervals of incident NAFLD. During 484,736.1 person-years of follow-up, 20,200 incident NAFLD cases were identified. In models adjusted for age, sex, year of visit, smoking status, alcohol intake, regular exercise, education level, and body mass index, the adjusted hazard ratio (95% confidence interval) for incident NAFLD comparing HBsAg-positive to HBsAg-negative participants was 0.83 (0.73-0.94). After introducing HBV infection and confounders (including homeostasis model assessment of insulin resistance and metabolic factors) as time-dependent exposures, the association between HBV infection and decreased risk of incident NAFLD was attenuated but persisted. These associations were consistently observed across clinically relevant, prespecified subgroups.

CONCLUSION

In this large cohort of apparently healthy Korean adults, HBsAg seropositivity was associated with lower risk of developing NAFLD, indicating a possible effect of HBV infection on the pathogenesis of NAFLD development. (Hepatology 2017;65:828-835).

Impact of hepatitis B virus infection on hepatic metabolic signaling pathway

A growing body of epidemiologic research has demonstrated that metabolic derangement exists in patients with hepatitis B virus (HBV) infection, indicating that there are clinical associations between HBV infection and host metabolism. In order to understand the complex interplay between HBV and hepatic metabolism in greater depth, we systematically reviewed these alterations in different metabolic signaling pathways due to HBV infection. HBV infection interfered with most aspects of hepatic metabolic responses, including glucose, lipid, nucleic acid, bile acid and vitamin metabolism. Glucose and lipid metabolism is a particular focus due to the significant promotion of gluconeogenesis, glucose aerobic oxidation, the pentose phosphate pathway, fatty acid synthesis or oxidation, phospholipid and cholesterol biosynthesis affected by HBV. These altered metabolic pathways are involved in the pathological process of not only hepatitis B, but also metabolic disorders, increasing the occurrence of complications, such as hepatocellular carcinoma and liver steatosis. Thus, a clearer understanding of the hepatic metabolic pathways affected by HBV and its pathogenesis is necessary to develop more novel therapeutic strategies targeting viral eradication.

Diverse impacts of the rs58542926 E167K variant in TM6SF2 on viral and metabolic liver disease phenotypes

A genome-wide exome association study has identified the transmembrane 6 superfamily member 2 (TM6SF2) rs58542926 variant encoding an E167K substitution as a genetic determinant of hepatic steatosis in nonalcoholic fatty liver disease (NAFLD). The roles of this variant across a spectrum of liver diseases and pathologies and on serum lipids comparing viral hepatitis to NAFLD and viral load in chronic viral hepatitis, as well as its intrahepatic molecular signature, have not been well characterized. We undertook detailed analyses in 3260 subjects with viral and nonviral liver diseases and in healthy controls. Serum inflammatory markers and hepatic expression of TM6SF2 and genes regulating lipid metabolism were assessed in a subset with chronic hepatitis C (CHC). The rs58542926 T allele was more prevalent in 502 NAFLD patients than controls (P = 0.02) but not different in cohorts with CHC (n = 2023) and chronic hepatitis B (n = 507). The T allele was associated with alterations in serum lipids and hepatic steatosis in all diseases and with reduced hepatic TM6SF2 and microsomal triglyceride transfer protein expression. Interestingly, the substitution was associated with reduced CHC viral load but increased hepatitis B virus DNA. The rs58542926 T allele had no effect on inflammation, impacted ≥F2 fibrosis in CHC and NAFLD assessed cross-sectionally (odds ratio = 1.39, 95% confidence interval 1.04-1.87, and odds ratio = 1.62, 95% confidence interval 1.03-2.52, respectively; P < 0.03 for both), but had no effect on fibrosis progression in 1174 patients with CHC and a known duration of infection.

CONCLUSION

The TM6SF2 E167K substitution promotes steatosis and lipid abnormalities in part by altering TM6SF2 and microsomal triglyceride transfer protein expression and differentially impacts CHC and chronic hepatitis B viral load, while effects on fibrosis are marginal. (Hepatology 2016;64:34-46).

PRKAA/AMPK restricts HBV replication through promotion of autophagic degradation

Adenosine monophosphate-activated protein kinase (AMPK) is a crucial energy sensor that maintains cellular energy homeostasis. AMPK plays a critical role in macroautophagy/autophagy, and autophagy facilitates hepatitis B virus (HBV) replication. To date, the intrinsic link among AMPK, autophagy and HBV production remains to be elucidated. Here, we demonstrate that PRKAA (a catalytic subunit of AMPK) is activated in response to HBV-induced oxidative stress, which in turn decreases the production of HBV. Mechanistic studies reveal that the autophagy machinery is associated with the inhibitory effect of PRKAA/AMPK on HBV production. Activation of PRKAA/AMPK promotes autolysosome-dependent degradation through stimulation of cellular ATP levels, which then leads to the depletion of autophagic vacuoles. Taken together, our data suggest that the activation of AMPK might be a stress response of host cells to restrict virus production through promotion of autophagic degradation. These findings therefore indicate that AMPK could provide a potential therapeutic target for HBV infection.

Molecular changes in hepatic metabolism and transport in cirrhosis and their functional importance

Liver cirrhosis is the common endpoint of many hepatic diseases and represents a relevant risk for liver failure and hepatocellular carcinoma. The progress of liver fibrosis and cirrhosis is accompanied by deteriorating liver function. This review summarizes the regulatory and functional changes in phase I and phase II metabolic enzymes as well as transport proteins and provides an overview regarding lipid and glucose metabolism in cirrhotic patients. Interestingly, phase I enzymes are generally downregulated transcriptionally, while phase II enzymes are mostly preserved transcriptionally but are reduced in their function. Transport proteins are regulated in a specific way that resembles the molecular changes observed in obstructive cholestasis. Lipid and glucose metabolism are characterized by insulin resistance and catabolism, leading to the disturbance of energy expenditure and wasting. Possible non-invasive tests, especially breath tests, for components of liver metabolism are discussed. The heterogeneity and complexity of changes in hepatic metabolism complicate the assessment of liver function in individual patients. Additionally, studies in humans are rare, and species differences preclude the transferability of data from rodents to humans. In clinical practice, some established global scores or criteria form the basis for the functional evaluation of patients with liver cirrhosis, but difficult treatment decisions such as selection for transplantation or resection require further research regarding the application of existing non-invasive tests and the development of more specific tests.

Interactions of Hepatitis B Virus Infection with Nonalcoholic Fatty Liver Disease: Possible Mechanisms and Clinical Impact

Hepatitis B virus (HBV) infection is a major etiology of chronic liver disease worldwide. In the past decade, nonalcoholic fatty liver disease (NAFLD) has emerged as a common liver disorder in general population. Accordingly, the patient number of chronic hepatitis B (CHB) concomitant with NAFLD grows rapidly. The present article reviewed the recent studies aiming to explore the relationship between CHB and NAFLD from different aspects, including the relevant pathogenesis of CHB and NAFLD, the intracellular molecular mechanisms overlaying HBV infection and hepatic steatosis, and the observational studies with animal models and clinical cohorts for analyzing the coincidence of the two diseases. It is concluded that although numerous cross-links have been suggested between the molecular pathways in HBV infection and NAFLD pathogenesis, regarding whether HBV infection can substantially interfere with the occurrence of NAFLD or vice versa in the patients, there is still far from a conclusive agreement.

Advances in treating drug-resistant hepatitis B virus in HIV-infected patients

INTRODUCTION

Treatment of HIV infection with nucleos(t)ide analogs active against hepatitis B virus (HBV) highly improves hepatic outcomes in HIV-HBV coinfected patients, especially when tenofovir (TDF) is part of the antiviral regimen. Drug resistance has been the major drawback and must remain as the most important caveat when planning to treat dually or HIV and HBV independently in coinfected patients.

AREAS COVERED

The use of lamivudine (LAM) as the only active anti-HBV agent should strongly be discouraged in HIV-HBV coinfected patients, although it might be considered for individuals with low serum HBV-DNA and in the absence of liver cirrhosis as an exception. In any other case drug resistance may cause any clinical benefit of this antiviral HBV therapy to disappear, and lead to cross-resistance with other antivirals and even occasionally select for HBV vaccine escape mutants. In cirrhotics, liver enzyme flares may be accompanied by life-threatening decompensation. Entecavir is generally not recommended as an anti-HBV agent in HIV-HBV coinfected patients given its low residual antiretroviral activity and potential for selection of resistance mutations in HIV. Adefovir is not active against HIV using HBV dosing and is no longer recommended as HBV therapy given its limited antiviral effect. Finally, telbivudine is not active against HIV, it is less potent than TDF against HBV and depicts low barrier to resistance and cross-resistance to LAM or emtricitabine.

EXPERT OPINION

The introduction of TDF has drastically reduced the clinical relevance of hepatitis B drug resistance in HIV-HBV coinfected individuals. The use of LAM as the only active anti-HBV agent should strongly be discouraged in this population.