Lay Summaries - Volume 67 Issue 2

Lay Summary: Hepatitis C virus (HCV) is highly variable, with seven genotypes and 67 subtypes characterized to date. The aim of this study was to i) compare two different methods of discriminating between genotypes; ii) investigate the prevalence of HCV subtypes for each genotype around the world; iii) find the prevalence of resistance-associated substitutions (RASs) in different subtypes. We found that both methods showed high concordance in genotype discrimination, but specific subtypes were not always identified accurately. Sequencing-based analyses demonstrated variations in regional subtype prevalence for some genotypes, notably within GT2, 4 and 6. RAS prevalence also varied by subtype. These variations could determine how successful different drugs are for treating HCV.
Lay Summary: The cell surface receptor SR-BI (scavenger receptor class B member 1), is essential for hepatitis C virus (HCV) entry into hepatocytes. Variations in the gene coding this receptor influence infectivity and viral load. We analyzed these variations to gain a better understanding of inter-individual differences over the course of HCV infection.
Lay Summary: Long-term treatment with antiviral drugs carries the risk of selecting mutations in the hepatitis B virus (HBV). We herein report two cases of patients with insufficient response to dual tenofovir and entecavir therapy. Molecular analyses identified a distinct mutation, rtS78T/sC69*, that abolishes HBsAg detection, enhances replication, sustains exosome-mediated virion secretion and decreases susceptibility to antivirals, thereby representing a potentially high-risk mutation for HBV-infected individuals.
Lay Summary: Hepatitis C virus infection continues to spread among HIV-positive men who have sex with men, especially among younger individuals. However, trends seem to differ by European region in recent years. Furthermore, men who have sex with men with a higher HIV RNA load were more likely to get infected with the hepatitis C virus. During recent HIV infection, MSM appear to be at higher risk of acquiring hepatitis C.
Lay Summary: The combination of direct-acting antivirals glecaprevir and pibrentasvir comprise a once-daily, all-oral, pangenotypic treatment for HCV genotype 1–6 infection. This article describes results from two phase II trials investigating a range of doses at treatment durations of 8 or 12 weeks in 449 patients without cirrhosis. Efficacy of the optimal dose, as determined by rates of sustained virologic response at post-treatment week 12, ranged from 92%-100%; treatment was well tolerated and significant laboratory abnormalities were rare.
Lay Summary: Degradation of the blood pigment heme yields the bile pigment bilirubin and the oxidation products Z-BOX A and Z-BOX B. Serum concentrations of these bioactive molecules increase in jaundice and can impair liver function and integrity. Amounts of Z-BOX A and Z-BOX B that are observed during liver failure in humans have profound effects on hepatic function when added to cultured liver cells or infused into healthy rats.
Lay Summary: Microparticles (MPs) are small vesicles that bleb from the membrane of every cell, including cancer cells, and are released to circulate in the bloodstream. Since their surface composition is similar to the surface of their underlying parental cell, MPs from the bloodstream can be isolated and by screening their surface components, the presence of their parental cells can be identified. This way, it was possible to detect and discriminate between patients bearing liver cancer and chronic liver cirrhosis.
Lay Summary: Targeted deep sequencing of single tumor specimen is a more efficient method to identify mutations in hepatocellular carcinoma made from mixed subtypes compared to circulating cell-free DNA in blood. cfDNA may serve as secondary alternative in profiling HCC genome. Identifying mutations may help clinicians choose targeted therapy for better individual treatments.
Lay Summary: Mortality rates due to HCC have increased in many countries over recent decades. In this study, we updated worldwide mortality trends for HCC from 1990 to 2014, and predicted trends for some countries to 2020. We observed unfavorable trends in Northern and Central Europe, North and Latin America. East Asia showed an improvement, however mortality rates in this region were 2- to 5-fold higher than in most European countries and the Americas. Steady declines to 2020 are predicted for East Asia but not for Europe and the Americas.
Lay Summary: OGT, a unique glycosyltransferase enzyme, was identified to be upregulated in non-alcoholic fatty liver disease-associated hepatocellular carcinoma tissues by transcriptome sequencing. Here, we found that OGT plays a role in cancer by promoting tumor growth and metastasis in both cell models and animal models. This effect is mediated by the induction of palmitic acid.
Lay Summary: Positron emission tomography (PET) using the radiolabelled bile acid (11C-CSar) enabled quantification of the individual steps of the hepatic transport of bile acids from blood to bile in man. Cholestasis reduced uptake and secretion and increased backflux to blood. These findings improve our understanding of cholestatic liver diseases and may support therapeutic decisions.
Lay Summary: Human and experimental data suggest that CD44, a cellular protein mainly expressed in immune cells, is a marker and key player of non-alcoholic steatohepatitis (NASH). Indeed, CD44 enhances the non-alcoholic fatty liver (NAFL) (hepatic steatosis) to NASH progression by regulating hepatic macrophage polarization (pro-inflammatory phenotype) and infiltration (macrophage motility and the MCP1/CCL2/CCR2 system). Targeting CD44 partially corrects NASH, making it a potential therapeutic strategy.
Lay Summary: The Rotterdam Study is a large ongoing population study of suburban inhabitants of Rotterdam in whom data on liver stiffness, as proxy for liver fibrosis, presence of fatty liver on ultrasound and detailed information on coffee and tea consumption were obtained in 2,424 participants. The consumption of herbal tea and daily consumption of three or more cups of coffee was related to the presence of lower liver stiffness, independent of a great number of other lifestyle and environmental factors. Previous studies have found a protective effect of coffee on established liver disease and we now show for the first time that this effect is already measurable in the general population.
Lay Summary: Hepatic activating transcription factor 3 (ATF3) may play an important role in oxidative stress-mediated hepatic steatosis and the development of type 2 diabetes (T2D) in a Zucker diabetic fatty (ZDF) rat model and in human patients with non-alcoholic fatty liver disease (NAFLD). Therefore, ATF3 may be a useful biomarker for predicting the progression of NAFLD and the development of T2D. Furthermore, given the significant association between hepatic ATF3 expression and both hepatic steatosis and impaired glucose homeostasis, in vivo ATF3 silencing may be a potential central strategy for preventing and managing NAFLD and T2D.
Lay Summary: Lack of animal models for iron overload disorders makes it hard to study the disease process for improving therapies. Feeding high iron diet to mice that lack the ß-catenin gene in liver cells led to increased inflammation followed by fat accumulation, cell death and wound healing that mimicked human disease. Administration of an antioxidant prevented hepatic injury in this model.