Mitochondrial stress in advanced fibrosis and cirrhosis associated with chronic hepatitis B, chronic hepatitis C, or nonalcoholic steatohepatitis.

BACKGROUND AND AIMS: Hepatitis B virus (HBV) infection causes oxidative stress (OS) and alters mitochondria in experimental models. Our goal was to investigate whether HBV might alter liver mitochondria also in humans, and the resulting mitochondrial stress might account for the progression of fibrosis in chronic hepatitis B (CHB). APPROACH AND RESULTS: The study included 146 treatment-naïve CHB mono-infected patients. Patients with CHB and advanced fibrosis (AF) or cirrhosis (F3-F4) were compared to patients with no/mild-moderate fibrosis (F0-F2). Patients with CHB were further compared to patients with chronic hepatitis C (CHC; n = 33), nonalcoholic steatohepatatis (NASH; n = 12), and healthy controls ( n = 24). We detected oxidative damage to mitochondrial DNA (mtDNA), including mtDNA strand beaks, and identified multiple mtDNA deletions in patients with F3-F4 as compared to patients with F0-F2. Alterations in mitochondrial function, mitochondrial unfolded protein response, biogenesis, mitophagy, and liver inflammation were observed in patients with AF or cirrhosis associated with CHB, CHC, and NASH. In vitro , significant increases of the mitochondrial formation of superoxide and peroxynitrite as well as mtDNA damage, nitration of the mitochondrial respiratory chain complexes, and impairment of complex I occurred in HepG2 cells replicating HBV or transiently expressing hepatitits B virus X protein. mtDNA damage and complex I impairment were prevented with the superoxide-scavenging Mito-Tempo or with inducible nitric oxide synthase (iNOS)-specific inhibitor 1400 W. CONCLUSIONS: Our results emphasized the importance of mitochondrial OS, mtDNA damage, and associated alterations in mitochondrial function and dynamics in AF or cirrhosis in CHB and NASH. Mitochondria might be a target in drug development to stop fibrosis progression.

New therapies for hepatitis delta virus infection.

Hepatitis delta virus (HDV) infection is a defective virus requiring hepatitis B virus (HBV) for its complete replication cycle. HDV is a small hepatotropic RNA virus and around 15 to 25 million people worldwide are living with chronic hepatitis delta (CHD) infection. However, the prevalence of HDV may be underestimated, and screening is frequently insufficient. HDV infection remains endemic in several regions including Central and West Africa, the Mediterranean basin, the Middle East, Eastern Europe, Northern Asia, certain areas of Southeast Asia and the Amazon basin of South America. The best preventive strategy to decrease HDV infection is to improve coverage of the prophylactic HBV vaccine. HDV infection may occur by HBV-HDV co-infection or superinfection, and the latter is usually more severe. CHD is associated with a higher risk of cirrhosis and hepatocellular carcinoma (HCC) compared to HBV mono-infection. Pegylated interferon alpha (PEG-IFNα) therapy is limited by moderate effectiveness (around 20%) and its adverse effects. The entry inhibitor, bulevirtide (BLV, Hepcludex® ), which was recently approved in Europe at a dose of 2 mg in sub-cutaneous injection per day, is indicated for the treatment of CHD in adult patients with compensated liver disease and positive HDV viremia. BLV can be administrated in monotherapy or in combination with PEG-IFNα. Nucleos(t)ide analogues can be used in combination for underlying HBV infection. The optimal treatment duration has not yet been determined and treatment should be continued if a clinical benefit is observed. There are other promising therapies such as IFN lambda (IFNλ) (immunomodulator), lonafarnib (prenylation inhibitor) and nucleic acid polymers (Inhibitors of HBsAg release). In this review, we will present an update on CHD and future promising treatments.

Early virological response in six patients with hepatitis D virus infection and compensated cirrhosis treated with Bulevirtide in real-life.

Hepatitis delta virus (HDV) infection is the most severe form of viral hepatitis. Bulevirtide (BLV, Hepcludex® ) is an HDV/HBV entry inhibitor approved in June 2020 in the European Union for adult patients with chronic hepatitis delta (CHD) and compensated liver disease and positive HDV RNA viral load. This real-life preliminary report described early virological efficacy and safety of BLV in six patients with CHD and compensated liver disease: four patients were treated with the combination of BLV (2 mg/d in subcutaneous injection) and pegylated interferon (PEG-IFN) and two patients with BLV monotherapy. Four patients treated with combined therapy had a decline of a minimum of 1 log10 and 3/3 of 2 log10 of HDV-VL at 12 and 24 weeks, respectively. One patient among four had stopped the treatment at 12 weeks because of thrombocytopenia and an HDV-VL relapse was notified 24 weeks after treatment cessation. Three patients among four (3/4) had undetectable HDV-VL during the therapy (<100 IU/ml). One patient (1/2) treated with BLV monotherapy had a decline of HDV-VL by 1 log10 at 8 weeks and 1/1 by 2 log10 at 28 week on-treatment. Two patients among four (2/4) with combined therapy had normal ALT reached at 4 and 56 weeks. One patient (1/2) with BLV monotherapy achieves ALT normalization at​ 4 weeks on treatment. Hepatitis B surface antigen (HBsAg) levels remain unchanged. Three among six (3/6) patients had an elevation of total biliary acids without pruritus. These early data generated confirm the interest in this new treatment. Final results will be important to demonstrate long-term clinical benefit (fibrosis reversibility and reduction in hepato-cellular carcinoma [HCC]).

Hepatitis B surface antigen seroclearance: Immune mechanisms, clinical impact, importance for drug development.

HBsAg seroclearance occurs rarely in the natural history of chronic hepatitis B (CHB) infection and is associated with improved clinical outcomes. Many factors are associated with HBsAg seroconversion, including immune and viral factors. However, the immune mechanisms associated with HBsAg seroclearance are still difficult to elucidate. HBsAg seroclearance is the ideal aim of HBV treatment. Unfortunately, this goal is rarely achieved with current treatments. Understanding the mechanisms of HBsAg loss appears to be important for the development of curative HBV treatments. While studies from animal models give insights into the potential immune mechanisms and interactions occurring between the immune system and HBsAg, they do not recapitulate all features of CHB in humans and are subject to variability due to their complexity. In this article, we review recent studies on these immune factors, focusing on their influence on CHB progression and HBsAg seroconversion. These data provide new insights for the development of therapeutic approaches to partially restore the anti-HBV immune response. Targeting HBsAg will ideally relieve the immunosuppressive effects on the immune system and help to restore anti-HBV immune responses.

Future treatments for hepatitis delta virus infection.

Around 15-20 million people develop chronic hepatitis delta virus worldwide. Hepatitis delta virus (HDV) is a defective RNA virus requiring the presence of the hepatitis B virus surface antigen (HBsAg) to complete its life cycle. HDV infects hepatocytes using the hepatitis B virus (HBV) receptor, the sodium taurocholate cotransporting polypeptide (NTCP). The HDV genome is a circular single-stranded RNA which encodes for a single hepatitis delta antigen (HDAg) that exists in two forms (S-HDAg and L-HDAg), and its replication is mediated by the host RNA polymerases. The HBsAg-coated HDV virions contain a ribonucleoprotein (RNP) formed by the RNA genome packaged with small and large HDAg. Farnesylation of the L-HDAg is the limiting step for anchoring this RNP to HBsAg, and thus for assembling, secreting and propagating virion particles. There is an important risk of morbidity and mortality caused by end-stage liver disease and hepatocellular carcinoma with HDV and current treatment is pegylated-interferon (PEG-IFN) for 48 weeks with no other options in patients who fail treatment. The ideal goal for HDV treatment is the clearance of HBsAg, but a reasonably achievable goal is a sustained HDV virological response (negative HDV RNA 6 months after stopping treatment). New drug development must take into account the interaction of HBV and HDV. In this review, we will present the new insights in the HDV life cycle that have led to the development of novel classes of drugs and discuss antiviral approaches in phase II and III of development: bulevirtide (entry inhibitor), lonafarnib, (prenylation inhibitor) and REP 2139 (HBsAg release inhibitor).

The Changing Demographics of Hepatitis B Virus Infection.

Hepatitis B virus infection remains a global public health problem with changing epidemiology due to several factors including vaccination policies and migration.

miRNAs as Potential Biomarkers for Viral Hepatitis B and C.

Around 257 million people are living with hepatitis B virus (HBV) chronic infection and 71 million with hepatitis C virus (HCV) chronic infection. Both HBV and HCV infections can lead to liver complications such as cirrhosis and hepatocellular carcinoma (HCC). To take care of these chronically infected patients, one strategy is to diagnose the early stage of fibrosis in order to treat them as soon as possible to decrease the risk of HCC development. microRNAs (or miRNAs) are small non-coding RNAs which regulate many cellular processes in metazoans. Their expressions were frequently modulated by up- or down-regulation during fibrosis progression. In the serum of patients with HBV chronic infection (CHB), miR-122 and miR-185 expressions are increased, while miR-29, -143, -21 and miR-223 expressions are decreased during fibrosis progression. In the serum of patients with HCV chronic infection (CHC), miR-143 and miR-223 expressions are increased, while miR-122 expression is decreased during fibrosis progression. This review aims to summarize current knowledge of principal miRNAs modulation involved in fibrosis progression during chronic hepatitis B/C infections. Furthermore, we also discuss the potential use of miRNAs as non-invasive biomarkers to diagnose fibrosis with the intention of prioritizing patients with advanced fibrosis for treatment and surveillance.

Targets and future direct-acting antiviral approaches to achieve hepatitis B virus cure.

Around 257 million people worldwide have chronic hepatitis B virus (HBV) infection, which leads to almost 1 million deaths per year from complications, mainly decompensated cirrhosis and hepatocellular carcinoma. The development of effective treatments for hepatitis C virus has led to hope for a cure for HBV. Current treatments for HBV infection include pegylated interferon-alfa, which is associated with modest efficacy and poor tolerability, or nucleoside analogues, which require lifelong administration and rarely achieve hepatitis B surface antigen (HBsAg) loss. Understanding the HBV lifecycle is essential to develop new approaches, since each step is a potential target for drug development. New direct-acting antivirals for HBV in development include entry inhibitors, capsid assembly modulators, and drugs targeting cccDNA or HBV RNA, and HBsAg secretion inhibitors. In this Review, we discuss potential targets and direct-acting antiviral approaches in development.