Circulating Neutrophil Dysfunction in HBV-Related Acute-on-Chronic Liver Failure

In vitro study: HIF-1α-dependent glycolysis enhances NETosis in hypoxic conditions

Background

Hypoxia plays a pivotal role in modulating immune responses, especially in neutrophils, which are essential components of the innate immune system. Hypoxia-inducible factor (HIF)-1α, a key transcription factor in hypoxic adaptation, regulates cellular metabolism and inflammatory responses. However, the impact of HIF-1α-dependent glycolysis on the formation of neutrophil extracellular traps (known as NETosis) under hypoxic conditions remains unclear.

Methods

We employed two established neutrophil models, neutrophils isolated from human whole blood and DMSO-induced dHL-60 cells, to explore the role of HIF-1α in regulating glycolysis and its influence on NETosis under hypoxic conditions. We utilized western blotting, immunofluorescence staining, ELISA, and flow cytometry to evaluate the expression of key glycolytic enzymes and NETosis markers under hypoxia. Additionally, the effects of inhibiting HIF-1α with LW6 and blocking the glycolytic pathway with Bay-876 were investigated.

Results

HIF-1α-dependent glycolysis, through the upregulation of key glycolytic enzymes, significantly enhances NETosis under hypoxic conditions. Pharmacological inhibition of HIF-1α with LW6 and glycolytic blockade with Bay-876 markedly reduced NETosis, underscoring the crucial role of metabolic reprogramming in neutrophil function during hypoxia.

Conclusion

This study provides novel insights into the interplay between metabolic reprogramming and NETosis in response to hypoxic stress. We identify HIF-1α-dependent glycolysis as a key driver of NETs formation, advancing our understanding of the mechanisms underlying hypoxia-related inflammatory diseases. These findings also suggest that targeting metabolic pathways may offer potential therapeutic strategies for modulating immune responses in hypoxia-associated disorders.

miR-126-3p Serves as a Biomarker for Hepatitis B Virus-Associated Chronic Acute Liver Failure and Regulates Inflammation by Regulating ERRFI1

Hepatitis B virus-associated chronic acute liver failure (HBV-ACLF) is the leading cause of ACLF, affecting approximately 90% of patients with ACLF. The objective of this study was to investigate the clinical relevance of miR-126-3p on HBV-ACLF as well as the regulatory impact of ERRFI1 and miR-126-3p on the inflammatory response caused by ACLF via in vitro experimental methodologies. RT-qPCR was utilized to quantify the expression levels of miR-126-3p, ERRFI1, NLRP3, caspase 1, and IL-1β. The clinical function of miR-126-3p was assessed using ROC analysis or Kaplan-Meier curve. Cell proliferation was quantified via the CCK-8 assay, while the dual-luciferase reporter assay was employed to confirm the specific binding interaction between miR-126-3p and ERRFI1. In patients with HBV-ACLF, a significant downregulation of miR-126-3p expression was observed; The level of miR-126-3p served as a prognostic indicator for the progression of HBV-ACLF, with reduced expression being associated with an unfavorable clinical outcome. In addition, miR-126-3p was found to modulate LPS-induced cell proliferation, and inflammation in THLE-2 cells through the regulation of ERRFI1 expression. Therefore, miR-126-3p might serve as a biomarker for HBV-ACLF.

Potential therapies for acute-on-chronic liver failure

Acute-on-chronic liver failure (ACLF) is a syndrome that develops in approximately 30% of patients hospitalised with cirrhosis and is characterised by an acute decompensation of liver function associated with extra-hepatic organ failures and a high short-term mortality. At present, no specific therapies are available for ACLF, and current management is limited to treatment of the precipitating event and organ support. Given the high prevalence and high mortality of this severe liver disease, there is an urgent need for targeted treatments. There is increasing evidence of the important role played by systemic inflammation and immune dysfunction in the pathophysiology of ACLF and a better understanding of these immune processes is resulting in new therapeutic targets. The aim of this review is to present an overview of ongoing studies of potentially promising therapies and how they could be utilised in the management of ACLF.

Omics in acute-on-chronic liver failure

Acute-on-chronic liver failure (ACLF) is a critical syndrome that develops in patients with chronic liver disease and is characterized by acute decompensation, single- or multiple-organ failure and high short-term mortality. Over the past few decades, ACLF has been progressively recognized as an independent clinical entity, and several criteria and prognostic scores have been proposed and validated by different scientific societies. However, controversies still exist in some aspects across regions, which mainly involve whether the definition of underlying liver diseases should include cirrhosis and non-cirrhosis. The pathophysiology of ACLF is complicated and remains unclear, although accumulating evidence based on different aetiologies of ACLF shows that it is closely associated with intense systemic inflammation and immune-metabolism disorder, which result in mitochondrial dysfunction and microenvironment imbalance, leading to disease development and organ failure. In-depth insight into the biological pathways involved in the mechanisms of ACLF and potential mechanistic targets that improve patient survival still needs to be investigated. Omics-based analytical techniques, including genomics, transcriptomics, proteomics, metabolomics and microbiomes, have developed rapidly and can offer novel insights into the essential pathophysiologic process of ACLF. In this paper, we briefly reviewed and summarized the current knowledge and recent advances in the definitions, criteria and prognostic assessments of ACLF; we also described the omics techniques and how omics-based analyses have been applied to investigate and characterize the biological mechanisms of ACLF and identify potential predictive biomarkers and therapeutic targets for ACLF. We also outline the challenges, future directions and limitations presented by omics-based analyses in clinical ACLF research.

Identification and validation of neutrophil-related biomarkers in acute-on-chronic liver failure

Dysfunction of peripheral blood neutrophils occurs in acute-on-chronic liver failure (ACLF). However, the molecular mechanisms of neutrophils involved in the pathophysiology of the ACLF remains poorly understood. Data downloaded from the GEO database (GSE142255) was used to identify both ACLF and neutrophil-related genes with the help of the limma package and Weighted Gene Co-Expression Network Analysis (WGCNA) algorithms. The analysis identified 288 ACLF-related differentially expressed genes (DEGs) in the circulating blood cells. Among these, three genes were found to be related to neutrophils and were identified as diagnostic genes, exhibiting high diagnostic efficacy as evidenced by an area under the curve (AUC) value of 1. Among these, matrix metallopeptidase-9 (MMP9) and S100 calcium binding protein A12 (S100A12) were upregulated, whereas C-C chemokine ligand 5 (CCL5) was downregulated in circulating immune cells from patients with ACLF compared to those from healthy controls. These findings were corroborated using an additional GEO dataset, GSE156382. The expression levels of the three key genes demonstrated a correlation with both ferroptosis and cuprotosis. Among the three diagnostic genes, only MMP9 was validated as differentially expressed through both quantitative real-time PCR (qRT-PCR) and western blot. Moreover, a significant elevation in plasma MMP9 levels was observed in patients with ACLF compared to those with chronic hepatitis B (CHB) and acute decompensated cirrhosis (AD). Notably, ACLF patients exhibiting elevated MMP9 levels (>175.8 ng/mL) experienced higher short-term mortality rates within both 30 and 90 days (p<0.001). In addition, a total of 21 drugs targeting the three diagnostic genes were identified from the Drug Bank database. Finally, the Kinase-TF-mRNA-miRNA network was constructed utilizing Cytoscape software. This study represents the initial application of WGCNA algorithms to identify novel biomarkers related to neutrophils in ACLF. Our findings offer new perspectives on the role of neutrophil in the pathogenesis of ACLF. However, additional research is required to substantiate the effects of these key genes and therapeutic agents on ACLF.

FPR1 affects acute rejection in kidney transplantation by regulating iron metabolism in neutrophils

BACKGROUND

Acute rejection (AR) is one of the significant factors contributing to poor prognosis in patients following kidney transplantation. Neutrophils are the main cause of early host-induced tissue injury. This paper intends to investigate the possible mechanisms of neutrophil involvement in acute rejection in renal transplantation.

METHODS

Samples were analyzed for their relationship with immune cells using CIBERSORT. WGCNA was used to identify modules with high relevance to neutrophils and hub genes in the modules were extracted. The effect on neutrophil function after blocking formyl peptide receptor 1 (FPR1) was tested in vitro experiments. The effects of blocking FPR1 on neutrophil function as well as acute rejection were tested in vivo after constructing a mouse kidney transplant model.

RESULTS

The proportion of neutrophils was higher in the AR group than in the non-rejection group, and FPR1 was identified as an important gene in the regulation of acute rejection in kidney transplantation by neutrophils. At the cellular level, blocking FPR1 inhibited the activation of the ERK1/2 pathway, decreased ferrous ion content, affected the expression of iron metabolism-related proteins, and suppressed the formation of NETs. In the acute rejection model of renal transplantation, blockade of FPR1 decreased graft neutrophil infiltration and NETs content. Meanwhile, blocking FPR1 attenuated graft injury during acute rejection.

CONCLUSION

This study found that FPR1 might be an important molecule involved in neutrophils during acute rejection of kidney transplantation, explored the relationship between kidney transplantation and neutrophils, and provided potential treatment methods for clinical practice.

Macrophage Evolution during Progression of Hepatitis Virus B-Related Acute-on-Chronic Liver Failure

INTRODUCTION

Hepatitis B virus (HBV)-related liver diseases, including hepatitis, cirrhosis, and liver failure, seriously threaten human lives and health worldwide. Innate and adaptive immune cells are all thought to participate in HBV-related diseases. However, there is a lack of information on the comprehensive landscape of the immune microenvironment.

METHODS

In this study, single-cell ribonucleic acid sequencing was performed on liver samples obtained from patients diagnosed with hepatitis, cirrhosis, and acute-on-chronic liver failure, which were caused by HBV. Trajectory analysis was performed to analyze the evolution of cell subsets, and branch expression analysis modeling was applied to visualize the changes in gene expression during evolution.

RESULTS

Finally, there was a significant increase in adaptive immune cells in the hepatitis and cirrhosis groups, whereas more innate immune cells were observed in the liver failure group. Furthermore, we found that monocytes underwent remarkable transcriptomic changes into FABP5+ macrophages, promoting the degranulation and chemotaxis of neutrophils through RESISTIN signaling, and LGMN+ macrophages, with the sequential activation of antigen presentation and defense to pathogens through SPP1 signaling.

CONCLUSION

Macrophages were revealed as central to the progression of acute-on-chronic liver failure as they regulated the activation or inhibition of other immune cells, which could help in developing an effective novel therapy.

Mesenchymal stromal cells alleviate APAP-induced liver injury via extracellular vesicle-mediated regulation of the miR-186-5p/CXCL1 axis

BACKGROUND

Acetaminophen (APAP) overdose is a significant cause of drug-induced liver injury (DILI). N-acetylcysteine (NAC) is the first-line agent used in the clinic. However, it rarely benefits patients with advanced APAP toxicity. Mesenchymal stromal cells (MSCs) have demonstrated potential in treating DILI. However, the specific mechanism by which MSCs protect against APAP-induced liver injury remains unclear.

METHODS

APAP was injected intraperitoneally to induce a liver injury model. We then detected histopathology, biochemical indices, and inflammatory cytokine levels to assess the efficacy of MSCs and MSC extracellular vesicles (MSC-EVs). Flow cytometry was performed to reveal the immunoregulatory effects of MSCs and MSC-EVs on the neutrophils. RNA sequencing (RNA-Seq) of liver tissues was used to identify critical target genes for MSC treatment.

RESULTS

MSC and MSC-EV treatment effectively alleviated APAP-induced liver injury and inhibited neutrophil infiltration. RNA-Seq analysis and ELISA data indicated that C-X-C motif chemokine 1 (CXCL1), a chemoattractant for neutrophils, was a key molecule in the MSC-mediated amelioration of APAP-induced liver damage. In addition, neutralization of CXCL1 reduced APAP-induced liver damage, which was accompanied by decreased neutrophil infiltration. Importantly, we verified that MSC-EV-derived miR-186-5p directly binds to the 3'-UTR of Cxcl1 to inhibit its expression in hepatocytes. The agomir miR-186-5p showed excellent potential for the treatment of DILI.

CONCLUSIONS

Our findings suggest that MSCs and MSC-EVs are an effective approach to mitigate DILI. Targeting the miR-186-5p/CXCL1 axis is a promising approach to improve the efficacy of MSCs and MSC-EVs in the treatment of DILI.

Metabolic Dysregulation and Metabolite Imbalances in Acute-on-chronic Liver Failure: Impact on Immune Status

Liver failure encompasses a range of severe clinical syndromes resulting from the deterioration of liver function, triggered by factors both within and outside the liver. While the definition of acute-on-chronic liver failure (ACLF) may vary by region, it is universally recognized for its association with multiorgan failure, a robust inflammatory response, and high short-term mortality rates. Recent advances in metabolomics have provided insights into energy metabolism and metabolite alterations specific to ACLF. Additionally, immunometabolism is increasingly acknowledged as a pivotal mechanism in regulating immune cell functions. Therefore, understanding the energy metabolism pathways involved in ACLF and investigating how metabolite imbalances affect immune cell functionality are crucial for developing effective treatment strategies for ACLF. This review methodically examined the immune and metabolic states of ACLF patients and elucidated how alterations in metabolites impact immune functions, offering novel perspectives for immune regulation and therapeutic management of liver failure.

Neutrophil extracellular traps in homeostasis and disease

Neutrophil extracellular traps (NETs), crucial in immune defense mechanisms, are renowned for their propensity to expel decondensed chromatin embedded with inflammatory proteins. Our comprehension of NETs in pathogen clearance, immune regulation and disease pathogenesis, has grown significantly in recent years. NETs are not only pivotal in the context of infections but also exhibit significant involvement in sterile inflammation. Evidence suggests that excessive accumulation of NETs can result in vessel occlusion, tissue damage, and prolonged inflammatory responses, thereby contributing to the progression and exacerbation of various pathological states. Nevertheless, NETs exhibit dual functionalities in certain pathological contexts. While NETs may act as autoantigens, aggregated NET complexes can function as inflammatory mediators by degrading proinflammatory cytokines and chemokines. The delineation of molecules and signaling pathways governing NET formation aids in refining our appreciation of NETs' role in immune homeostasis, inflammation, autoimmune diseases, metabolic dysregulation, and cancer. In this comprehensive review, we delve into the multifaceted roles of NETs in both homeostasis and disease, whilst discussing their potential as therapeutic targets. Our aim is to enhance the understanding of the intricate functions of NETs across the spectrum from physiology to pathology.

Neutrophil Extracellular Trap Scores Predict 90-Day Mortality in Hepatitis B-Related Acute-on-Chronic Liver Failure

Hepatitis B virus (HBV)-related acute-on-chronic liver failure (ACLF) is associated with pronounced systemic inflammation, and neutrophil extracellular traps (NETs) are key components of this response. The primary objective of this study was to establish an NET-related scoring system for patients with HBV-ACLF. A prospective training cohort of 81 patients from the Beijing Ditan Hospital was included. The concentrations of NET markers (cell-free DNA, myeloperoxidase DNA [MPO-DNA], and citrullinated histone H3) in peripheral blood were quantified. Random survival forest, LASSO regression, and multivariate Cox regression analyses were used to identify prognostic factors associated with 90-day mortality in ACLF patients and develop a nomogram for visualization, which was followed by evaluation in a validation cohort (n = 40). NET-related marker levels were significantly higher in the non-survival group than in the survival group (p < 0.05). The NET score was constructed by combining MPO-DNA, neutrophil-to-lymphocyte ratio, and age data. The score's diagnostic effectiveness, assessed by the area under the curve, yielded values of 0.83 and 0.77 in the training and validation sets, respectively, markedly surpassing those of other established models (p < 0.05). In both groups, the 90-day mortality rates were 88.8% and 75.0%, respectively, for patients categorized as high risk and 18.0% and 12.5%, respectively, for those classified as low risk.

Evidence-based incorporation of key parameters into MELD score for acute-on-chronic liver failure

BACKGROUND

The model for end-stage liver disease (MELD) score is widely used for the prognostication in end-stage liver disease but has limited performance in acute-on-chronic liver failure (ACLF). In this study, we identified additional predictive parameters and reformed the MELD score to predict ACLF more accurately.

METHODS

A meta-analysis was performed on relevant studies to identify the predictive factors of 28-day/90-day outcomes of ACLF, which were validated in two large prospective cohorts. A prognostic score was developed by incorporating predictive parameters into the MELD score. The model was evaluated with a focus on discrimination and calibration.

RESULTS

The meta-analysis incorporated 32 cohort studies with a total of 13 939 patients, of which 13 risk factors were identified, and 3 risk factors (age, neutrophil count and hepatic encephalopathy (HE) grade) besides MELD score were validated in 751 patients with ACLF derived from two prospective cohorts. A new model (Chinese Acute-on-Chronic Liver Failure Consortium (CATCH-LIFE)-MELD score) was developed as follows: 0.028×age+0.3×HE grade+0.039×neutrophil count+0.079×MELD score. CATCH-LIFE-MELD score achieved a concordance index of 0.791/0.788 for 28-day/90-day outcomes, which is superior to other traditional scores. Other discrimination indices, including net reclassification improvement, integrated discrimination improvement and probability density function, and calibration including Nagelkerke's R2 and Brier scores confirmed its superiority. Moreover, the accuracy of CATCH-LIFE-MELD score remained stable. It was highest in patients with or without hepatitis B virus infection, cirrhosis, liver failure or under the Chinese Group on the Study of Severe Hepatitis B (COSSH) criteria or European Association for the Study of the Liver (EASL) criteria. All results were substantiated by an evaluation using an external cohort.

CONCLUSIONS

CATCH-LIFE-MELD score, a modified MELD score exhibited improved accuracy in predicting the short-term prognosis of ACLF than other traditional scores.

Single-Cell RNA Sequencing Reveals the Spatial Heterogeneity and Functional Alteration of Endothelial Cells in Chronic Hepatitis B Infection

Chronic Hepatitis B virus (CHB) infection is a global health challenge, causing damage ranging from hepatitis to cirrhosis and hepatocellular carcinoma. In our study, single-cell RNA sequencing (scRNA-seq) analysis was performed in livers from mice models with chronic inflammation induced by CHB infection and we found that endothelial cells (ECs) exhibited the largest number of differentially expressed genes (DEGs) among all ten cell types. NF-κB signaling was activated in ECs to induce cell dysfunction and subsequent hepatic inflammation, which might be mediated by the interaction of macrophage-derived and cholangiocyte-derived VISFATIN/Nampt signaling. Moreover, we divided ECs into three subclusters, including periportal ECs (EC_Z1), midzonal ECs (EC_Z2), and pericentral ECs (EC_Z3) according to hepatic zonation. Functional analysis suggested that pericentral ECs and midzonal ECs, instead of periportal ECs, were more vulnerable to HBV infection, as the VISFATIN/Nampt- NF-κB axis was mainly altered in these two subpopulations. Interestingly, pericentral ECs showed increasing communication with macrophages and cholangiocytes via the Nampt-Insr and Nampt-Itga5/Itgb1 axis upon CHB infection, which contribute to angiogenesis and vascular capillarization. Additionally, ECs, especially pericentral ECs, showed a close connection with nature killer (NK) cells and T cells via the Cxcl6-Cxcr6 axis, which is involved in shaping the microenvironment in CHB mice livers. Thus, our study described the heterogeneity and functional alterations of three subclusters in ECs. We revealed the potential role of VISFATIN/Nampt signaling in modulating ECs characteristics and related hepatic inflammation, and EC-derived chemokine Cxcl16 in shaping NK and T cell recruitment, providing key insights into the multifunctionality of ECs in CHB-associated pathologies.

Outcome Predictors of Acute-on-Chronic Liver Failure: A Narrative Review

Complications of acute-on-chronic liver failure (ACLF) include increased short-term mortality. Extrahepatic organ failures result from chronic liver disease and acute hepatic injury. This combination characterizes end-stage liver disease. Its rapid progression makes it challenging for hepatologists and intensivists to treat. The varied definitions of this condition lead to varied clinical presentations. Hepatic or extrahepatic failures are more prevalent in chronic hepatitis B or cirrhosis patients who receive an additional injury. Numerous intensity parameters and prognosis ratings, including those for hepatitis B virus (HBV), have been developed and verified for various patients and causes of the disease. Liver regeneration, liver transplantation (LT), or antiviral therapy for HBV-related ACLF are the main treatment aims for various organ failures. LT is the best treatment for HBV-ACLF. In some HBV-related ACLF patients, nucleos(t)ide analogs and artificial liver assistance may enhance survival. Combining epidemiological and clinical studies, this review updates our understanding of HBV-ACLF's definition, diagnosis, epidemiology, etiology, therapy, and prognosis.

Characteristics and risk factors for invasive fungal infection in hospitalized patients with acute-on-chronic hepatitis B liver failure: a retrospective cohort study from 2010 to 2023

BACKGROUND AND AIM

The global burden of invasive fungal infections (IFIs) is emerging in immunologic deficiency status from various disease. Patients with acute-on-chronic hepatitis B liver failure (ACHBLF) are prone to IFI and their conditions are commonly exacerbated by IFI. However, little is known about the characteristics and risk factors for IFI in hospitalized ACHBLF patients.

METHODS

A total of 243 hospitalized ACHBLF patients were retrospectively enrolled from January 2010 to July 2023. We performed restricted cubic spline analysis to determine the non-linear associations between independent variables and IFI. The risk factors for IFI were identified using logistic regression and the extreme gradient boosting (XGBoost) algorithm. The effect values of the risk factors were determined by the SHapley Additive exPlanations (SHAP) method.

RESULTS

There were 24 ACHBLF patients (9.84%) who developed IFI on average 17.5 (13.50, 23.00) days after admission. The serum creatinine level showed a non-linear association with the possibility of IFI. Multiple logistic regression revealed that length of hospitalization (OR = 1.05, 95% CI: 1.02-1.08, P = 0.002) and neutrophilic granulocyte percentage (OR = 1.04, 95% CI: 1.00-1.09, P = 0.042) were independent risk factors for IFI. The XGBoost algorithm showed that the use of antibiotics (SHAP value = 0.446), length of hospitalization (SHAP value = 0.406) and log (qHBV DNA) (SHAP value = 0.206) were the top three independent risk factors for IFI. Furthermore, interaction analysis revealed no multiplicative effects between the use of antibiotics and the use of glucocorticoids (P = 0.990).

CONCLUSION

IFI is a rare complication that leads to high mortality in hospitalized ACHBLF patients, and a high neutrophilic granulocyte percentage and length of hospitalization are independent risk factors for the occurrence of IFI.

Overview of the immunological mechanisms in hepatitis B virus reactivation: Implications for disease progression and management strategies

Hepatitis B virus (HBV) reactivation is a clinically significant challenge in disease management. This review explores the immunological mechanisms underlying HBV reactivation, emphasizing disease progression and management. It delves into host immune responses and reactivation's delicate balance, spanning innate and adaptive immunity. Viral factors' disruption of this balance, as are interactions between viral antigens, immune cells, cytokine networks, and immune checkpoint pathways, are examined. Notably, the roles of T cells, natural killer cells, and antigen-presenting cells are discussed, highlighting their influence on disease progression. HBV reactivation's impact on disease severity, hepatic flares, liver fibrosis progression, and hepatocellular carcinoma is detailed. Management strategies, including anti-viral and immunomodulatory approaches, are critically analyzed. The role of prophylactic anti-viral therapy during immunosuppressive treatments is explored alongside novel immunotherapeutic interventions to restore immune control and prevent reactivation. In conclusion, this comprehensive review furnishes a holistic view of the immunological mechanisms that propel HBV reactivation. With a dedicated focus on understanding its implications for disease progression and the prospects of efficient management strategies, this article contributes significantly to the knowledge base. The more profound insights into the intricate interactions between viral elements and the immune system will inform evidence-based approaches, ultimately enhancing disease management and elevating patient outcomes. The dynamic landscape of management strategies is critically scrutinized, spanning anti-viral and immunomodulatory approaches. The role of prophylactic anti-viral therapy in preventing reactivation during immunosuppressive treatments and the potential of innovative immunotherapeutic interventions to restore immune control and proactively deter reactivation.

Primary sarcopenia is associated with elevated spontaneous NET formation

Introduction: Sarcopenia is a frequent complication of liver cirrhosis, but it can also occur independently as a result of any underlying cause. The immune system plays an important role in the pathogenesis of both liver cirrhosis and sarcopenia. Neutrophil function, including neutrophil extracellular trap (NET) formation, is linked to chronic inflammation; however, it has not been extensively studied in patients with sarcopenia. Here, we aim to study if main neutrophil functions, such as phagocytosis, reactive oxygen species (ROS) production, and NET formation, are altered in patients with sarcopenia with or without liver cirrhosis. Methods: Neutrophils from 92 patients (52 patients with liver cirrhosis and sarcopenia, 25 patients with liver cirrhosis without sarcopenia, and 15 patients with sarcopenia without liver cirrhosis) and 10 healthy controls were isolated and stimulated with heat-inactivated E. coli (250 bacteria/cell), phorbol 12-myristate 13-acetate (PMA) (100 nM), or incubation medium in duplicates for 2 h at 37°C. Cells were fixed with paraformaldehyde and stained with 4',6-diamidino-2-phenylindole (DAPI). Pictures of 10 random fields of vision per slide were taken with an Olympus BX51 fluorescence microscope (Olympus, Shinjuku, Tokyo, Japan) at 600x total magnification. The DNA Area and NETosis Analysis (DANA) algorithm was used to quantify the percentage of NET formation per patient. Phagocytosis and ROS production were assessed with the PhagotestTM kit and PhagoburstTM kit (Glycotope, Heidelberg, Germany) in 92 patients and 21 healthy controls, respectively. Results: Spontaneous NET formation was significantly elevated in patients with only sarcopenia compared to patients with cirrhosis and sarcopenia (p = 0.008) and healthy controls (p = 0.039). NET formation in response to PMA was significantly decreased in patients with cirrhosis (p = 0.007), cirrhosis and sarcopenia (p < 0.001), and sarcopenia (p = 0.002) compared to healthy controls. There was no significant difference in NET formation in response to E. coli between the groups. The DANA algorithm was successfully optimized and validated for assessment of clinical samples. There were no significant changes in neutrophil phagocytosis between patients' groups compared to healthy controls. A significantly lower percentage of neutrophils produced ROS in response to N-formylmethionine-leucyl-phenylalanine (fMLF) in patients compared to healthy controls. Discussion: Spontaneous NET formation might contribute to chronic inflammation and sarcopenia pathogenesis. This, however, does not result in the impairment of the NET formation function of neutrophils in response to a bacterial stimulus and, therefore, cannot be not linked with the increased risk of bacterial infections neither in sarcopenia nor in cirrhosis. The semi-automated NET formation analysis can be successfully implemented to analyze the vast amount of data generated within clinical studies. This approach opens up the possibilities to develop an NET formation-based biomarker in different diseases including sarcopenia and implement NET formation analysis into clinical settings. Phagocytosis and ROS production were not affected in patients with sarcopenia. Further research is needed to explore the mechanism of NET formation in patients with sarcopenia and its potential as a biomarker in sarcopenia.

Characteristics of circulating immune cells in HBV-related acute-on-chronic liver failure following artificial liver treatment

BACKGROUND AND AIM

Liver failure, which is predominantly caused by hepatitis B (HBV) can be improved by an artificial liver support system (ALSS). This study investigated the phenotypic heterogeneity of immunocytes in patients with HBV-related acute-on-chronic liver failure (HBV-ACLF) before and after ALSS therapy.

METHODS

A total of 22 patients with HBV-ACLF who received ALSS therapy were included in the study. Patients with Grade I according to the ACLF Research Consortium score were considered to have improved. Demographic and laboratory data were collected and analyzed during hospitalization. Immunological features of peripheral blood in the patients before and after ALSS were detected by mass cytometry analyses.

RESULTS

In total, 12 patients improved and 10 patients did not. According to the immunological features data after ALSS, the proportion of circulating monocytes was significantly higher in non-improved patients, but there were fewer γδT cells compared with those in improved patients. Characterization of 37 cell clusters revealed that the frequency of effector CD8+ T (P = 0.003), CD4+ TCM (P = 0.033), CD4+ TEM (P = 0.039), and inhibitory natural killer (NK) cells (P = 0.029) decreased in HBV-ACLF patients after ALSS therapy. Sub group analyses after treatment showed that the improved patients had higher proportions of CD4+ TCM (P = 0.010), CD4+ TEM (P = 0.021), and γδT cells (P = 0.003) and a lower proportion of monocytes (P = 0.012) compared with the non-improved patients.

CONCLUSIONS

Changes in effector CD8+ T cells, effector and memory CD4+ T cells, and inhibitory NK cells are associated with ALSS treatment of HBV-ACLF. Moreover, monocytes and γδT cells exhibited the main differences when patients obtained different prognoses. The phenotypic heterogeneity of lymphocytes and monocytes may contribute to the prognosis of ALSS and future immunotherapy strategies.

The glucose metabolic reprogramming in hepatitis B virus infection and hepatitis B virus associated diseases

Hepatitis B virus (HBV) infection is closely related to viral hepatitis, liver cirrhosis, and hepatocellular carcinoma. HBV infection can reprogram metabolism processes of the host cells including glucose metabolism. The aberrant glucose metabolism may aid in viral infection and immune escape and may contribute to liver associated pathology. In this review, we discussed the interplay between HBV infection and glucose metabolism, which may provide new insights into HBV infection and pathology, novel intervention targets for HBV-related diseases.

Clinical determinants of hospital mortality in liver failure: a comprehensive analysis of 62,717 patients

BACKGROUND

Liver failure (LF) is characterised by a loss of the synthetic and metabolic liver function and is associated with a high mortality. Large-scale data on recent developments and hospital mortality of LF in Germany are missing. A systematic analysis and careful interpretation of these datasets could help to optimise outcomes of LF.

METHODS

We used standardised hospital discharge data of the Federal Statistical Office to evaluate current trends, hospital mortality and factors associated with an unfavourable course of LF in Germany between 2010 and 2019.

RESULTS

A total of 62,717 hospitalised LF cases were identified. Annual LF frequency decreased from 6716 (2010) to 5855 (2019) cases and was higher among males (60.51%). Hospital mortality was 38.08% and significantly declined over the observation period. Mortality significantly correlated with patients' age and was highest among individuals with (sub)acute LF (47.5%). Multivariate regression analyses revealed pulmonary (ORARDS: 2.76, ORmechanical ventilation: 6.46) and renal complications (ORacute kidney failure: 2.04, ORhepatorenal syndrome: 2.92) and sepsis (OR: 1.92) as factors for increased mortality. Liver transplantation reduced mortality in patients with (sub)acute LF. Hospital mortality significantly decreased with the annual LF case volume and ranged from 47.46% to 29.87% in low- or high-case-volume hospitals, respectively.

CONCLUSIONS

Although incidence rates and hospital mortality of LF in Germany have constantly decreased, hospital mortality has remained at a very high level. We identified a number of variables associated with increased mortality that could help to improve framework conditions for the treatment of LF in the future.

Acute-on-chronic liver failure: far to go-a review

Acute-on-chronic liver failure (ACLF) has been recognized as a severe clinical syndrome based on the acute deterioration of chronic liver disease and is characterized by organ failure and high short-term mortality. Heterogeneous definitions and diagnostic criteria for the clinical condition have been proposed in different geographic regions due to the differences in aetiologies and precipitating events. Several predictive and prognostic scores have been developed and validated to guide clinical management. The specific pathophysiology of ACLF remains uncertain and is mainly associated with an intense systemic inflammatory response and immune-metabolism disorder based on current evidence. For ACLF patients, standardization of the treatment paradigm is required for different disease stages that may provide targeted treatment strategies for individual needs.

PADs and NETs in digestive system: From physiology to pathology

Peptidylarginine deiminases (PADs) are the only enzyme class known to deiminate arginine residues into citrulline in proteins, a process known as citrullination. This is an important post-translational modification that functions in several physiological and pathological processes. Neutrophil extracellular traps (NETs) are generated by NETosis, a novel cell death in neutrophils and a double-edged sword in inflammation. Excessive activation of PADs and NETs is critically implicated in their transformation from a physiological to a pathological state. Herein, we review the physiological and pathological functions of PADs and NETs, in particular, the involvement of PAD2 and PAD4 in the digestive system, from inflammatory to oncological diseases, along with related therapeutic prospects.

The immunological function of CXCR2 in the liver during sepsis

Background

The chemokine receptor CXCR2 and its ligands, especially CXCL8, are crucial mediators for the progression of liver inflammation and liver failure in sepsis. Neutrophils have the highest CXCR2 expression in mice and humans, and their activation via CXCL8 facilitates their migration to the inflamed liver for the clearance of the pathogens and, in turn, the inflammation.

Main body

In sepsis, the inflammatory insult causes extensive neutrophil migration to the liver that overwhelms the immune response. To compensate for the strong receptor activation, CXCR2 desensitizes, incapacitating the immune cells to efficiently clear pathogens, causing further life-threatening liver damage and uncontrolled pathogen spread.

Conclusion

CXCR2 function during infection strongly depends on the expressing cell type. It signals pro- and anti-inflammatory effects that may prompt novel cell-type-specific CXCR2-directed therapeutics.

Characterization of intrahepatic B cells in acute-on-chronic liver failure

Background and objectives

Acute on chronic liver failure (ACLF) is characterized by the immunologic dissonance during the prolonged pathogenic development. Both abnormal innate immune response and adaptive T-cell response have been reported in patients with ACLF; however, less is known regarding B cells in ACLF pathogenesis. Previous reports were only based on immunophenotyping of peripheral blood samples. Here, we aim to dissect liver-infiltrating B-cell subpopulation in ACLF.

Methods

Paired liver perfusate and peripheral blood were freshly collected from healthy living donors and recipients during liver transplantation. Liver tissues were obtained from patients with ACLF, cirrhosis, and healthy controls. Flow cytometry was used to characterize the phenotypic and functional alterations in intrahepatic and circulating B-cell populations from ACLF, cirrhosis, and healthy controls. The expression of CD19⁺ and CD138⁺ on liver tissues was examined by immunohistochemistry staining.

Results

In this study, we first deciphered the intrahepatic B cells subsets of patients with ACLF. We found that the ACLF liver harbored reduced fraction of naïve B cells and elevated percentage of CD27⁺CD21^- activated memory B cells (AM), CD27^-CD21^- atypical memory B cells (atMBC), CD27⁺IgD^-IgM⁺(IgM⁺ memory B cells), and CD27⁺CD38⁺⁺ plasma cells than cirrhosis and healthy controls. Moreover, these B subpopulations demonstrated enhanced activation and altered effector functions. Specifically, the ACLF liver was abundant in atMBC expressing higher CD11c and lower CD80 molecule, which was significantly correlated to alanine aminotransferase and aspartate aminotransferase. In addition, we found that intrahepatic CD27⁺CD38⁺⁺plasma cells were preferentially accumulated in ACLF, which expressed more CD273 (PD-L2) and secreted higher granzyme B and IL-10. Finally, the enriched hepatic plasma B cells were in positive association with disease severity indices including alkaline phosphatase and gamma-glutamyl transferase.

Conclusions

In this pilot study, we showed an intrahepatic B-cell landscape shaped by the ACLF liver environment, which was distinct from paired circulating B-cell subsets. The phenotypic and functional perturbation in atMBC and plasma cells highlighted the unique properties of infiltrating B cells during ACLF progression, thereby denoting the potential of B-cell intervention in ACLF therapy.

Network pharmacology-based prediction of active compounds in the Wenyang Jiedu Huayu formula acting on acute-on-chronic liver failure with experimental support in vitro and in vivo

Acute-on-chronic liver failure (ACLF) is characterized by undermined liver function, massive necrosis/apoptosis of hepatocytes, and hepatic inflammatory cell recruitment, leading to multiorgan failure. Traditional Chinese medicine (TCM) has been widely applied in clinical and experimental studies of ACLF. In this study, 23 compounds with 6,386 drug targets were obtained from Wenyang Jiedu Huayu (WYJDHY), and 8,096 genes were identified as ACLF disease targets, among which 3,132 were overlapping co-targets. Expression profile analysis identified 105 DEGs among the co-targets, which were associated with biological activities such as lymphocyte activation, immune response regulation, and pathways such as Th17 cell differentiation and NF-κB signaling. After PPI analysis and network construction, atractylenolide I (AT-1) has been identified as the hub active ingredient of the WYJDHY formula. LPS stimulation inhibited rat hepatocytes’ BRL 3A cell viability, promoted cell apoptosis, increased the levels of ALT, AST, IL-6, and VCAM-1 within the culture medium, and activated NF-κB signaling, whereas AT-1 treatment significantly attenuated LPS-induced toxicity on BRL 3A cells. Furthermore, the NF-κB signaling inhibitor PDTC exerted effects on LPS-stimulated BRL 3A cells similar to those of AT-1, and the combination of PDTC and AT-1 further attenuated LPS-induced toxicity on BRL 3A cells. In vivo, AT-1 alone or with PDTC improved the symptoms and local inflammation in ACLF model rats. In conclusion, 23 active ingredients of six herbs in the WYJDHY formula were retrieved, and 105 co-targets were differentially expressed in ACLF. AT-1 exerts protective effects on LPS-stimulated hepatocytes and ACLF rats, possibly by inhibiting the NF-κB pathway.

Acute decompensation events differentially impact the risk of nosocomial infections and short-term outcomes in patients with cirrhosis

Aims

This research aimed to evaluate the influence of acute decompensation (AD) events upon admission on the subsequent risk of nosocomial infections (NIs) and the synergy between AD and the following NIs on the short-term outcome.

Methods

A total of 419 hospitalized individuals with cirrhosis and AD participated in the current study. Various AD events at admission and outcomes in patients with or without NIs were compared. The logistic regression and Cox proportional hazards models were designed for NIs development and liver transplant (LT)-free mortality at 28 and 90 days, respectively.

Results

During hospitalization, 91 patients developed NIs. Notably, a higher proportion of patients with NIs had jaundice (52.7 vs. 30.5%; p < 0.001) and bacterial infections (37.4 vs. 20.7%; p = 0.001) at admission compared to patients without NIs, while a lower proportion suffered gastrointestinal hemorrhage (16.5 vs. 36.6%; p < 0.001). Multivariate analysis revealed that jaundice was independently linked with the development of NIs (OR, 2.732; 95% CI: 1.104–6.762). The 28-day (16.5 vs. 7.3%; p = 0.008) and 90-day (27.5 vs. 15.9%; p = 0.011) LT-free mortality rates of patients with NIs were significantly higher than those without NIs. According to the Cox proportional hazards model, jaundice remained an independent risk factor for 90-day death (HR, 5.775; 95% CI: 1.217–27.397). The connection between total bilirubin and 90-day mortality was nonlinear, and a 6 mg/mL threshold was proposed.

Conclusion

The types of AD events differentially predispose to risk of NIs. Presenting jaundice at admission is independently associated with NIs occurrence and increased 90-day mortality of patients with NIs. Antibiotic prophylaxis may benefit this specific subset of patients.

Jieduan–Niwan Formula Ameliorates Oxidative Stress and Apoptosis in Acute-on-Chronic Liver Failure by Suppressing HMGB1/TLR-4/NF-κB Signaling Pathway: A Study In Vivo and In Vitro

Jieduan-Niwan (JDNW) formula is a traditional Chinese medicine compound created by the famous Chinese medicine expert Professor Qian Ying, and has been used clinically for decades to treat acute-on-chronic liver failure (ACLF) and exhibits remarkable efficacy. However, the exact mechanism remains to be discovered. As an important hepatocyte damage-associated molecular patterns (DAMP) factor, high mobility group box 1 (HMGB1) is a potential therapeutic target as an accelerator of ACLF in the pathogenesis. Therefore, the present study investigated whether JDNW inhibits the overexpression and cytoplasmic translocation of HMGB1 in ACLF liver tissue and alleviates its mediated oxidative stress and apoptosis. In vivo, an immune-induced ACLF rat model was established, and then treated with JDNW for 5, 10, and 15 d. The results showed that a large number of cytoplasmic translocations of HMGB1 occurred in the ACLF group. And there was an increase in the expression of HMGB1 in the M-5 d group. After the intervention of JDNW, the overexpression and translocation of HMGB1 were inhibited. In vitro, D-GaLN caused an increase in the expression and translocation of HMGB1 in L02 cells. Similar to the inhibitor of HMGB1, JDNW serum alleviated this kind of increase. Further tests showed that JDNW attenuated ACLF-related oxidative stress and apoptosis, and the inhibition was associated with the regulation of TLR-4/NF-κB signaling pathway. In conclusion, our present findings suggest that the therapeutic effect of JDNW on ACLF was associated with the inhibition of high expression and cytoplasmic translocation of HMGB1 during the acute injury phase, thus, attenuating oxidative stress injury and apoptosis induced by HMGB1/TLR-4/NF-κB pathway.

The Immune Pathogenesis of Acute-On-Chronic Liver Failure and the Danger Hypothesis

Acute-on-chronic liver failure (ACLF) is a group of clinical syndromes related to severe acute liver function impairment and multiple-organ failure caused by various acute triggering factors on the basis of chronic liver disease. Due to its severe condition, rapid progression, and high mortality, it has received increasing attention. Recent studies have shown that the pathogenesis of ACLF mainly includes direct injury and immune injury. In immune injury, cytotoxic T lymphocytes (CTLs), dendritic cells (DCs), and CD4⁺ T cells accumulate in the liver tissue, secrete a variety of proinflammatory cytokines and chemokines, and recruit more immune cells to the liver, resulting in immune damage to the liver tissue, massive hepatocyte necrosis, and liver failure, but the key molecules and signaling pathways remain unclear. The “danger hypothesis” holds that in addition to the need for antigens, damage-associated molecular patterns (DAMPs) also play a very important role in the occurrence of the immune response, and this hypothesis is related to the pathogenesis of ACLF. Here, the research status and development trend of ACLF, as well as the mechanism of action and research progress on various DAMPs in ACLF, are summarized to identify biomarkers that can predict the occurrence and development of diseases or the prognosis of patients at an early stage.

A neutrophil-to-lymphocyte ratio-based prognostic model to predict mortality in patients with HBV-related acute-on-chronic liver failure

Background

Although the Asian Pacific Association for the Study of the Liver acute-on-chronic liver failure (ACLF) research consortium (AARC) ACLF score is easy to use in patients with hepatitis b virus-related ACLF (HBV-ACLF), serum lactate is not routinely tested in primary hospitals, and its value may be affected by some interference factors. Neutrophil-to-lymphocyte ratio (NLR) is used to assess the status of bacterial infection (BI) or outcomes in patients with various diseases. We developed an NLR-based AARC ACLF score and compared it with the existing model.

Methods

A total of 494 HBV-ACLF patients, enrolled in four tertiary academic hospitals in China with 90-day follow-up, were analysed. Prognostic performance of baseline NLR and lactate were compared between cirrhotic and non-cirrhotic subgroups via the receiver operating curve and Kaplan–Meier analyses. A modified AARC ACLF (mAARC ACLF) score using NLR as a replacement for lactate was developed (n = 290) and validated (n = 204).

Results

There were significantly higher baseline values of NLR in non-survivors, patients with admission BI, and those with higher grades of ACLF compared with the control groups. Compared with lactate, NLR better reflected BI status in the cirrhotic subgroup, and was more significantly correlated with CTP, MELD, MELD-Na, and the AARC score. NLR was an independent predictor of 90-day mortality, and was categorized into three risk grades (< 3.10, 3.10–4.78, and > 4.78) with 90-day cumulative mortalities of 8%, 21.2%, and 77.5% in the derivation cohort, respectively. The mAARC ACLF score, using the three grades of NLR instead of corresponding levels of lactate, was superior to the other four scores in predicting 90-day mortality in the derivation (AUROC 0.906, 95% CI 0.872–0.940, average P < 0.001) and validation cohorts (AUROC 0.913, 95% CI 0.876–0.950, average P < 0.01), with a considerable performance in predicting 28-day mortality in the two cohorts.

Conclusions

The prognostic value of NLR is superior to that of lactate in predicting short-term mortality risk in cirrhotic and non-cirrhotic patients with HBV-ACLF. NLR can be incorporated into the AARC ACLF scoring system for improving its prognostic accuracy and facilitating the management guidance in patients with HBV-ACLF in primary hospitals.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-02007-w.

Inflammatory signature in acute-on-chronic liver failure includes increased expression of granulocyte genes ELANE, MPO and CD177

Acute-on-Chronic Liver Failure (ACLF) is associated with innate immune dysfunction and high short-term mortality. Neutrophils have been identified to influence prognosis in ACLF. Neutrophil biology is under-evaluated in ACLF. Therefore, we investigated neutrophil-specific genes and their association with ACLF outcomes. This is an observational study. Enriched granulocytes, containing neutrophils, isolated from study participants in three groups- ACLF(n = 10), chronic liver disease (CLD, n = 4) and healthy controls (HC, n = 4), were analysed by microarray. Differentially expressed genes were identified and validated by qRT-PCR in an independent cohort of ACLF, CLD and HC (n = 30, 15 and 15 respectively). The association of confirmed overexpressed genes with ACLF 28-day non-survivors was investigated. The protein expression of selected neutrophil genes was confirmed using flow cytometry and IHC. Differential gene expression analysis showed 1140 downregulated and 928 upregulated genes for ACLF versus CLD and 2086 downregulated and 1091 upregulated genes for ACLF versus HC. Significant upregulation of neutrophilic inflammatory signatures were found in ACLF compared to CLD and HC. Neutrophil enriched genes ELANE, MPO and CD177 were highly upregulated in ACLF and their expression was higher in ACLF 28-day non-survivors. Elevated expression of CD177 protein on neutrophil surface in ACLF was confirmed by flow cytometry. IHC analysis in archival post mortem liver biopsies showed the presence of CD177+ neutrophils in the liver tissue of ACLF patients. Granulocyte genes ELANE, MPO and CD177 are highly overexpressed in ACLF neutrophils as compared to CLD or HC. Further, this three-gene signature is highly overexpressed in ACLF 28-day non-survivors.

Risk of Reactivation of Hepatitis B Virus (HBV) and Tuberculosis (TB) and Complications of Hepatitis C Virus (HCV) Following Tocilizumab Therapy: A Systematic Review to Inform Risk Assessment in the COVID-19 Era

Objectives: Tocilizumab (TCZ), an IL-6 receptor antagonist, is used in the treatment of severe COVID-19 caused by infection with SARS-CoV-2. However, unintended consequences of TCZ therapy include reactivation of tuberculosis (TB) or hepatitis B virus (HBV), and worsening of hepatitis C virus (HCV). We set out to assimilate existing data for these complications, in order to help inform evidence-based risk assessments for the use of TCZ, and thus to reduce the risk of serious but preventable complications. Methods: We searched the global WHO database of Individual Case Safety Reports (ICSRs) and adverse drug reactions (ADRs) ("VigiBase") and undertook a systematic literature review, in accordance with PRISMA guidelines. We generated mean cumulative incidence estimates for infection complications. Results: Mean cumulative incidence of HBV and TB were 3.3 and 4.3%, respectively, in patients receiving TCZ. Insufficient data were available to generate estimates for HCV. These estimates derive from heterogeneous studies pre-dating SARS-CoV-2, with differing epidemiology and varied approaches to screening and prophylaxis, so formal meta-analysis was not possible. Conclusions: We underline the need for careful individual risk assessment prior to TCZ prescription, and present an algorithm to guide clinical stratification. There is an urgent need for ongoing collation of safety data as TCZ therapy is used in COVID.