Single-cell RNA-sequencing of virus-specific cellular immune responses in chronic hepatitis B patients.

Chronic hepatitis B (CHB) is a major global health challenge. CHB can be controlled by antivirals but a therapeutic cure is lacking. CHB is characterized by limited HBV-specific T cell reactivity and functionality and expression of inhibitory receptors. The mechanisms driving these T cell phenotypes are only partially understood. Here, we created a single-cell RNA-sequencing dataset of HBV immune responses in patients to contribute to a better understanding of the dysregulated immunity. Blood samples of a well-defined cohort of 21 CHB and 10 healthy controls, including a subset of 5 matched liver biopsies, were collected. scRNA-seq data of total immune cells (55,825) plus sorted HBV-specific (1,963), non-naive (32,773) and PD1+ T cells (96,631) was generated using the 10X Genomics platform (186,123 cells) or the full-length Smart-seq2 protocol (1,069 cells). The shared transcript count matrices of single-cells serve as a valuable resource describing transcriptional changes underlying dysfunctional HBV-related T cell responses in blood and liver tissue and offers the opportunity to identify targets or biomarkers for HBV-related immune exhaustion.

Tight Junction Proteins as Therapeutic Targets to Treat Liver Fibrosis and Hepatocellular Carcinoma.

In the last decade tight junction proteins exposed at the surface of liver or cancer cells have been uncovered as mediators of liver disease biology: Claudin-1 and Occludin are host factors for hepatitis C virus entry and Claudin-1 has been identified as a driver for liver fibrosis and hepatocellular carcinoma (HCC). Moreover, Claudins have emerged as therapeutic targets for liver disease and HCC. CLDN1 expression is upregulated in liver fibrosis and HCC. Monoclonal antibodies (mAbs) targeting Claudin-1 have completed preclinical proof-of-concept studies for treatment of liver fibrosis and HCC and are currently in clinical development for advanced liver fibrosis. Claudin-6 overexpression is associated with an HCC aggressive phenotype and treatment resistance. Claudin-6 mAbs or chimeric antigen receptor-T cells therapies are currently being clinically investigated for Claudin-6 overexpressing tumors. In conclusion, targeting Claudin proteins offers a novel clinical opportunity for the treatment of patients with advanced liver fibrosis and HCC.

Spontaneous idiopathic liver hemorrhage: a systematic review of a rare entity.

BACKGROUND: Spontaneous idiopathic liver hemorrhage (SILH) is a rare life-threatening condition occurring without a clear and specific etiology. A systematic review was performed to provide guidelines for the perioperative management of patients affected by SILH. A case report was also included. METHODS: A systematic search of the last 24-year literature was conducted and the manuscript was structured following point-by-point the PRISMA guidelines. RESULTS: After an initial selection of 6995 titles, 15 articles were considered for the final qualitative analysis (n = 22 patients, including the present report). Conservative treatment was chosen in 12 cases (54.5%) with stable clinical conditions, while 9 patients (40.9%) required a primary operative approach for emergency presentation at diagnosis. Direct liver resection was the preferred surgical treatment (n = 6), mostly major hepatectomies (n = 4). Hepatic arterial embolization was performed as the primary operative approach in three patients, followed by emergency laparotomy during the same hospitalization because of rebleeding in one case. Contrast-enhanced CT scan was the gold standard for diagnosis (n = 19). CONCLUSIONS: Conservative treatment of SILH is mainly based on stable clinical conditions and may be considered even in case of a limited arterial blush found on imaging. The absence of underlying hepatic or systemic disorders seems to correlate with favorable outcomes and no mortality.

Impact of anti-HDV reflex testing at HBs antigen positive discovery in a single center France: Support for primary HDV screening in France.

BACKGROUND: Hepatitis Delta virus (HDV) infection is a major cause of liver-related morbidity and mortality in patients infected with HBV, with a global HDV prevalence uncertain. In France, 2 to 5 % of HBs antigen (HBsAg) carriers present anti-HDV antibodies (anti-HDV). The EASL recommends testing for anti-HDV in all HBsAg-positive patients. Since January 2022, we have systematically carried out anti-HDV serology when a positive HBsAg is discovered (new HBsAg carriers). OBJECTIVES: We evaluated the benefit of anti-HDV reflex testing after one year of practice by comparing anti-HDV and HBsAg serology data over the last six years, among the new HBsAg carriers and all the HBsAg carriers. STUDY DESIGN: HBsAg and anti-HDV were screened using the Abbott Architect HBsAg quanti kit and the DIA.PRO HDVAb kit. Serological, demographic, virological, and clinical data were analyzed. RESULTS: Implementing anti-HDV reflex testing leads to more than a 2-fold increase in diagnoses of HDV infection among all HBsAg carriers. If the anti-HDV positive rate remains stable among the new HBsAg carriers, a significant increase in the anti-HDV positive rate from 6.8 % to 10.3 % was observed considering all HBsAg carriers. Interestingly, the discovery of anti-HDV carriage increased from 3.9 % to 6.5 % in 2022, allowing earlier identification of HBV-HDV-infected patients and a fast referral to hepatologists for adequate clinical management and, in some cases, the introduction of bulevirtide-based therapy. CONCLUSIONS: Our preliminary results at one year seem promising and evaluating the cost-effectiveness of reflex tests in real life with feedback would be helpful.

Left-sided portal hypertension: Update and proposition of management algorithm.

Left-sided or segmental portal hypertension (SPHT) is a rare entity, most often associated with pancreatic disease or antecedent pancreatic surgery. The starting point is splenic vein obstruction secondary to local inflammation or, less often, extrinsic compression. SPHT leads to splenomegaly and development of collateral porto-systemic venous circulation. SPHT should be suspected in patients with pancreatic history who present with episodic upper gastrointestinal bleeding and splenomegaly with normal liver function tests. The most common clinical presentation is major upper gastrointestinal bleeding secondary to rupture of esophageal and/or gastric varices. At the present time, there are no management recommendations for SPHT, particularly when the patient is asymptomatic. In patients with upper gastro-intestinal bleeding, hemostasis can be obtained either by medical or interventional means according to patient status and available resources. For symptomatic patients, splenectomy is the reference treatment. Recently, less invasive, radiologic procedures, such as splenic artery embolization, have been developed as an alternative to surgery. Additionally, sonography-guided endoscopic hemostasis can also be envisioned, leading to the diagnosis and treatment of the lesion by elastic band ligation or by glue injection into the varices during the same procedure. The goal of this article is to describe the pathophysiological mechanisms behind SPHT and its clinical manifestations and treatment, based on a review of the literature. Because of the absence of recommendations for the management of SPHT, we propose a decisional algorithm for the management of SPHT based on the literature.

Treatment of HCC with claudin-1-specific antibodies suppresses carcinogenic signaling and reprograms the tumor microenvironment.

BACKGROUND & AIMS: Despite recent approvals, the response to treatment and prognosis of patients with advanced hepatocellular carcinoma (HCC) remain poor. Claudin-1 (CLDN1) is a membrane protein that is expressed at tight junctions, but it can also be exposed non-junctionally, such as on the basolateral membrane of the human hepatocyte. While CLDN1 within tight junctions is well characterized, the role of non-junctional CLDN1 and its role as a therapeutic target in HCC remains unexplored. METHODS: Using humanized monoclonal antibodies (mAbs) specifically targeting the extracellular loop of human non-junctional CLDN1 and a large series of patient-derived cell-based and animal model systems we aimed to investigate the role of CLDN1 as a therapeutic target for HCC. RESULTS: Targeting non-junctional CLDN1 markedly suppressed tumor growth and invasion in cell line-based models of HCC and patient-derived 3D ex vivo models. Moreover, the robust effect on tumor growth was confirmed in vivo in a large series of cell line-derived xenograft and patient-derived xenograft mouse models. Mechanistic studies, including single-cell RNA sequencing of multicellular patient HCC tumorspheres, suggested that CLDN1 regulates tumor stemness, metabolism, oncogenic signaling and perturbs the tumor immune microenvironment. CONCLUSIONS: Our results provide the rationale for targeting CLDN1 in HCC and pave the way for the clinical development of CLDN1-specific mAbs for the treatment of advanced HCC. IMPACT AND IMPLICATIONS: Hepatocellular carcinoma (HCC) is associated with high mortality and unsatisfactory treatment options. Herein, we identified the cell surface protein Claudin-1 as a treatment target for advanced HCC. Monoclonal antibodies targeting Claudin-1 inhibit tumor growth in patient-derived ex vivo and in vivo models by modulating signaling, cell stemness and the tumor immune microenvironment. Given the differentiated mechanism of action, the identification of Claudin-1 as a novel therapeutic target for HCC provides an opportunity to break the plateau of limited treatment response. The results of this preclinical study pave the way for the clinical development of Claudin-1-specific antibodies for the treatment of advanced HCC. It is therefore of key impact for physicians, scientists and drug developers in the field of liver cancer and gastrointestinal oncology.

A monoclonal antibody targeting nonjunctional claudin-1 inhibits fibrosis in patient-derived models by modulating cell plasticity.

Tissue fibrosis is a key driver of end-stage organ failure and cancer, overall accounting for up to 45% of deaths in developed countries. There is a large unmet medical need for antifibrotic therapies. Claudin-1 (CLDN1) is a member of the tight junction protein family. Although the role of CLDN1 incorporated in tight junctions is well established, the function of nonjunctional CLDN1 (njCLDN1) is largely unknown. Using highly specific monoclonal antibodies targeting a conformation-dependent epitope of exposed njCLDN1, we show in patient-derived liver three-dimensional fibrosis and human liver chimeric mouse models that CLDN1 is a mediator and target for liver fibrosis. Targeting CLDN1 reverted inflammation-induced hepatocyte profibrogenic signaling and cell fate and suppressed the myofibroblast differentiation of hepatic stellate cells. Safety studies of a fully humanized antibody in nonhuman primates did not reveal any serious adverse events even at high steady-state concentrations. Our results provide preclinical proof of concept for CLDN1-specific monoclonal antibodies for the treatment of advanced liver fibrosis and cancer prevention. Antifibrotic effects in lung and kidney fibrosis models further indicate a role of CLDN1 as a therapeutic target for tissue fibrosis across organs. In conclusion, our data pave the way for further therapeutic exploration of CLDN1-targeting therapies for fibrotic diseases in patients.

Safety and Antiviral Activity of EGFR Inhibition by Erlotinib in Chronic Hepatitis C Patients: A Phase Ib Randomized Controlled Trial.

INTRODUCTION: Significant hepatocellular carcinoma (HCC) risk persists after chronic hepatitis C (CHC) cure. Preclinical studies have shown that erlotinib, an oral epidermal growth factor receptor (EGFR) inhibitor, has an antiviral activity and HCC chemopreventive effect. Erlotinib is metabolized in the liver, and its safety in patients with CHC is unknown. This study aimed to assess the safety and antiviral activity of erlotinib in patients with CHC. METHODS: In this investigator-initiated dose-escalation phase Ib prospective randomized double-blind placebo-controlled study, noncirrhotic hepatitis C virus (HCV) patients received placebo or erlotinib (50 or 100 mg/d) for 14 days with a placebo-erlotinib ratio of 1:3. Primary end points were safety and viral load reduction at the end of treatment (EOT). The secondary end point was viral load reduction 14 days after EOT. RESULTS: This study analyzed data of 3 patients receiving placebo, 3 patients receiving erlotinib 50 mg/d, and 3 patients receiving erlotinib 100 mg/d. One grade 3 adverse event was reported in the placebo group (liver enzymes elevation), leading to treatment discontinuation and patient replacement, and 1 in the erlotinib 100 mg/d group (pericarditis), which was not considered to be treatment-related. Grade 2 skin rash was observed in 1 erlotinib 100 mg/d patient. No significant HCV-RNA level reduction was noted during treatment, but 2 of the 3 patients in the erlotinib 100 mg/d group showed a decrease of >0.5 log HCV-RNA 14 days after EOT. DISCUSSION: Erlotinib demonstrated to be safe in noncirrhotic CHC patients. An antiviral activity at 100 mg/d confirms a functional role of EGFR as an HCV host factor in patients. These results provide perspectives to further study erlotinib as an HCC chemopreventive agent in patients with CHC.

Conventional and artificial intelligence-based imaging for biomarker discovery in chronic liver disease.

Chronic liver diseases, resulting from chronic injuries of various causes, lead to cirrhosis with life-threatening complications including liver failure, portal hypertension, hepatocellular carcinoma. A key unmet medical need is robust non-invasive biomarkers to predict patient outcome, stratify patients for risk of disease progression and monitor response to emerging therapies. Quantitative imaging biomarkers have already been developed, for instance, liver elastography for staging fibrosis or proton density fat fraction on magnetic resonance imaging for liver steatosis. Yet, major improvements, in the field of image acquisition and analysis, are still required to be able to accurately characterize the liver parenchyma, monitor its changes and predict any pejorative evolution across disease progression. Artificial intelligence has the potential to augment the exploitation of massive multi-parametric data to extract valuable information and achieve precision medicine. Machine learning algorithms have been developed to assess non-invasively certain histological characteristics of chronic liver diseases, including fibrosis and steatosis. Although still at an early stage of development, artificial intelligence-based imaging biomarkers provide novel opportunities to predict the risk of progression from early-stage chronic liver diseases toward cirrhosis-related complications, with the ultimate perspective of precision medicine. This review provides an overview of emerging quantitative imaging techniques and the application of artificial intelligence for biomarker discovery in chronic liver disease.

Differences between sporadic hyperplastic gastric polyps and portal hypertensive gastric polyps: a review.

Portal hypertension (PH) is one of the most severe complications of chronic liver diseases. It is defined as an increase in pressure in the portal venous system which results in a portosystemic gradient >5 mmHg. In the western world, cirrhosis is the most frequent cause of PH, mainly due to nonalcoholic fatty liver disease and alcoholic liver disease. Patients with PH have esophageal varices in 68-73% of cases, portal hypertensive gastropathy in 51-73% and hyperplastic polyps (HPs) in 0.9-2%. Recent studies have shown that HPs found in PH patients are different from classical HPs. They constitute a new entity called portal hypertensive polyps (PHPs). The main difference between sporadic HPs and PHP is the presence of larger and more numerous vascular capillaries in the lamina propria. The clinical course of PHPs is unknown. Their physiopathology seems different from HPs: the increased congestion caused by higher portal pressure in the stomach may induce capillaries proliferation and neoangiogenesis. PHPs may be responsible for symptoms, such as pyloric obstruction, iron deficiency and anemia. Their prevalence in portal hypertensive and cirrhotic patients is from 1% to 8%. PHPs can be single or numerous, in the antrum or the gastric corpus. Their size ranges from 2 to 3 cm. PHPs seem to disappear or shrink with the treatment of PH. They should be resected in case of symptom and if >10 mm, after Helicobacter pylori eradication if present. However, their recurrence is frequent (40-79%), thus surveillance endoscopy is mandatory, at the same time as esophageal varices.

A human liver cell-based system modeling a clinical prognostic liver signature for therapeutic discovery.

Chronic liver disease and hepatocellular carcinoma (HCC) are life-threatening diseases with limited treatment options. The lack of clinically relevant/tractable experimental models hampers therapeutic discovery. Here, we develop a simple and robust human liver cell-based system modeling a clinical prognostic liver signature (PLS) predicting long-term liver disease progression toward HCC. Using the PLS as a readout, followed by validation in nonalcoholic steatohepatitis/fibrosis/HCC animal models and patient-derived liver spheroids, we identify nizatidine, a histamine receptor H2 (HRH2) blocker, for treatment of advanced liver disease and HCC chemoprevention. Moreover, perturbation studies combined with single cell RNA-Seq analyses of patient liver tissues uncover hepatocytes and HRH2+, CLEC5Ahigh, MARCOlow liver macrophages as potential nizatidine targets. The PLS model combined with single cell RNA-Seq of patient tissues enables discovery of urgently needed targets and therapeutics for treatment of advanced liver disease and cancer prevention.

Hepatitis B virus compartmentalization and single-cell differentiation in hepatocellular carcinoma.

Chronic hepatitis B virus (HBV) infection is a major cause of hepatocellular carcinoma (HCC) world-wide. The molecular mechanisms of viral hepatocarcinogenesis are still partially understood. Here, we applied two complementary single-cell RNA-sequencing protocols to investigate HBV-HCC host cell interactions at the single cell level of patient-derived HCC. Computational analyses revealed a marked HCC heterogeneity with a robust and significant correlation between HBV reads and cancer cell differentiation. Viral reads significantly correlated with the expression of HBV-dependency factors such as HLF in different tumor compartments. Analyses of virus-induced host responses identified previously undiscovered pathways mediating viral carcinogenesis, such as E2F- and MYC targets as well as adipogenesis. Mapping of fused HBV-host cell transcripts allowed the characterization of integration sites in individual cancer cells. Collectively, single-cell RNA-Seq unravels heterogeneity and compartmentalization of both, virus and cancer identifying new candidate pathways for viral hepatocarcinogenesis. The perturbation of pro-carcinogenic gene expression even at low HBV levels highlights the need of HBV cure to eliminate HCC risk.

Liver Disease and Coronavirus Disease 2019: From Pathogenesis to Clinical Care.

Infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus that emerged in late 2019, is posing an unprecedented challenge to global health. Coronavirus disease 2019 (COVID-19), the clinical disease caused by SARS-CoV-2, has a variable presentation ranging from asymptomatic infection to life-threatening acute respiratory distress syndrome and multiorgan failure. Liver involvement is common during COVID-19 and exhibits a spectrum of clinical manifestations from asymptomatic elevations of liver function tests to hepatic decompensation. The presence of abnormal liver tests has been associated with a more severe presentation of COVID-19 disease and overall mortality. Although SARS-CoV-2 RNA has been detected in the liver of patients with COVID-19, it remains unclear whether SARS-CoV-2 productively infects and replicates in liver cells and has a direct liver-pathogenic effect. The cause of liver injury in COVID-19 can be attributed to multiple factors, including virus-induced systemic inflammation, hypoxia, hepatic congestion, and drug-induced liver disease. Among patients with cirrhosis, COVID-19 has been associated with hepatic decompensation and liver-related mortality. Additionally, COVID-19's impact on health care resources can adversely affect delivery of care and outcomes of patients with chronic liver disease. Understanding the underlying mechanisms of liver injury during COVID-19 will be important in the management of patients with COVID-19, especially those with advanced liver disease. This review summarizes our current knowledge of SARS-CoV-2 virus-host interactions in the liver as well the clinical impact of liver disease in COVID-19.

Targeting clinical epigenetic reprogramming for chemoprevention of metabolic and viral hepatocellular carcinoma.

OBJECTIVE: Hepatocellular carcinoma (HCC) is the fastest-growing cause of cancer-related mortality with chronic viral hepatitis and non-alcoholic steatohepatitis (NASH) as major aetiologies. Treatment options for HCC are unsatisfactory and chemopreventive approaches are absent. Chronic hepatitis C (CHC) results in epigenetic alterations driving HCC risk and persisting following cure. Here, we aimed to investigate epigenetic modifications as targets for liver cancer chemoprevention. DESIGN: Liver tissues from patients with NASH and CHC were analysed by ChIP-Seq (H3K27ac) and RNA-Seq. The liver disease-specific epigenetic and transcriptional reprogramming in patients was modelled in a liver cell culture system. Perturbation studies combined with a targeted small molecule screen followed by in vivo and ex vivo validation were used to identify chromatin modifiers and readers for HCC chemoprevention. RESULTS: In patients, CHC and NASH share similar epigenetic and transcriptomic modifications driving cancer risk. Using a cell-based system modelling epigenetic modifications in patients, we identified chromatin readers as targets to revert liver gene transcription driving clinical HCC risk. Proof-of-concept studies in a NASH-HCC mouse model showed that the pharmacological inhibition of chromatin reader bromodomain 4 inhibited liver disease progression and hepatocarcinogenesis by restoring transcriptional reprogramming of the genes that were epigenetically altered in patients. CONCLUSION: Our results unravel the functional relevance of metabolic and virus-induced epigenetic alterations for pathogenesis of HCC development and identify chromatin readers as targets for chemoprevention in patients with chronic liver diseases.

Risk Factors, Pathogenesis, and Strategies for Hepatocellular Carcinoma Prevention: Emphasis on Secondary Prevention and Its Translational Challenges.

Hepatocellular carcinoma (HCC) is a leading cause of cancer-associated mortality globally. Given the limited therapeutic efficacy in advanced HCC, prevention of HCC carcinogenesis could serve as an effective strategy. Patients with chronic fibrosis due to viral or metabolic etiologies are at a high risk of developing HCC. Primary prevention seeks to eliminate cancer predisposing risk factors while tertiary prevention aims to prevent HCC recurrence. Secondary prevention targets patients with baseline chronic liver disease. Various epidemiological and experimental studies have identified candidates for secondary prevention-both etiology-specific and generic prevention strategies-including statins, aspirin, and anti-diabetic drugs. The introduction of multi-cell based omics analysis along with better characterization of the hepatic microenvironment will further facilitate the identification of targets for prevention. In this review, we will summarize HCC risk factors, pathogenesis, and discuss strategies of HCC prevention. We will focus on secondary prevention and also discuss current challenges in translating experimental work into clinical practice.