Increased Expression of Cytotoxic T-Lymphocyte-Associated Protein 4 by T Cells, Induced by B7 in Sera, Reduces Adaptive Immunity in Patients With Acute Liver Failure

Immunological Mechanisms and Effects of Bacterial Infections in Acute-on-Chronic Liver Failure

Acute-on-chronic liver failure (ACLF) is a severe clinical syndrome characterized by high morbidity and mortality rates. Bacterial infection is a frequent precipitating factor and complication in ACLF patients, significantly worsening patient outcomes. Elucidating the mechanisms underlying bacterial infections and their impact on ACLF pathophysiology is crucial for developing effective therapies to reduce infection rates and mortality. Current research highlights that immune suppression in ACLF increases susceptibility to bacterial infections, which in turn exacerbate immune dysfunction. However, a comprehensive review summarizing the emerging mechanisms underlying this immunosuppression is currently lacking. This review aims to provide an overview of the latest research, focusing on alterations in the immune responses of innate immune cells-including monocytes, macrophages, and neutrophils-as well as adaptive immune cells such as T and B lymphocytes during the onset and progression of bacterial infections in ACLF. In addition, recent advances in immunomodulatory therapies, including stem cell-based interventions, will also be discussed.

Application of Human Plasma/Serum to Cell Culture In Vitro: A Translational Research Approach to Better Define Disease Mechanisms

In vitro cell culture experiments play an important role in medical research. Various cellular mechanisms and signaling pathways have been identified with in vitro experimental techniques. Unfortunately, the clinical and translational impact of these studies is often limited due to their inability to closely resemble physiological or pathophysiological milieus in cell culture and the use of unrealistic experimental conditions. Thus, further developments must be made to improve the translation of in vitro cell culture work. The application of human plasma or serum as a stimulus for cells, human or otherwise, is a relatively new approach that ultimately overcomes many of the in vitro limitations and provides a more physiologically relevant model. While this technique has been used for the investigation of various diseases and pharmacological mechanisms, discrepancies remain regarding the appropriate methodologies. This review provides insight into recent findings through the application of human plasma or serum as stimuli, as well as an analysis of methodological considerations and suggestions for future directions.

Development and First Clinical Use of an Extracorporeal Artificial Multiorgan System in Acute-on-Chronic Liver Failure Patients

Multiple organ failure (MOF) is a common and deadly condition. Patients with liver cirrhosis with acute-on-chronic liver failure (AOCLF) are particularly susceptible. Excess fluid accumulation in tissues makes routine hemodialysis generally ineffective because of cardiovascular instability. Patients with three or more organ failures face a mortality rate of more than 90%. Many cannot survive liver transplantation. Extracorporeal support systems like MARS (Baxter, Deerfield, IL) and Prometheus (Bad Homburg, Germany) have shown promise but fall short in bridging patients to transplantation. A novel Artificial Multi-organ Replacement System (AMOR) was developed at the University of Washington Medical Center. AMOR removes protein-bound toxins through a combination of albumin dialysis, a charcoal sorbent column, and a novel rinsing method to prevent sorbent column saturation. It removes excess fluid through hemodialysis. Ten AOCLF patients with over three organ failures were treated by the AMOR system. All patients showed significant clinical improvement. Fifty percent of the cohort received liver transplants or recovered liver function. AMOR was successful in removing large amounts of excess body fluid, which regular hemodialysis could not. AMOR is cost-effective and user-friendly. It removes excess fluid, supporting the other vital organs such as liver, kidneys, lungs, and heart. This pilot study's results encourage further exploration of AMOR for treating MOF patients.

Development and validation of risk prediction model for bacterial infections in acute liver failure patients

Infections significantly increase mortality in acute liver failure (ALF) patients, and there are no risk prediction models for early diagnosis and treatment of infections in ALF patients. This study aims to develop a risk prediction model for bacterial infections in ALF patients to guide rational antibiotic therapy. The data of ALF patients admitted to the Second Hospital of Hebei Medical University in China from January 2017 to January 2022 were retrospectively analyzed for training and internal validation. Patients were selected according to the updated 2011 American Association for the Study of Liver Diseases position paper on ALF. Serological indicators and model scores were collected within 24 h of admission. New models were developed using the multivariate logistic regression analysis. An optimal model was selected by receiver operating characteristic (ROC) analysis, Hosmer-Lemeshow test, the calibration curve, the Brier score, the bootstrap resampling, and the decision curve analysis. A nomogram was plotted to visualize the results. A total of 125 ALF patients were evaluated and 79 were included in the training set. The neutrophil-to-lymphocyte ratio and sequential organ failure assessment (SOFA) were integrated into the new model as independent predictive factors. The new SOFA-based model outperformed other models with an area under the ROC curve of 0.799 [95% confidence interval (CI): 0.652-0.926], the superior calibration and predictive performance in internal validation. High-risk individuals with a nomogram score ≥26 are recommended for antibiotic therapy. The new SOFA-based model demonstrates high accuracy and clinical utility in guiding antibiotic therapy in ALF patients.

Standard-Volume Is As Effective As High-Volume Plasma Exchange for Patients With Acute Liver Failure

Background/Aims

Acute liver failure (ALF) is associated with fatal outcomes without liver transplantation. Two randomized studies reported standard volume (SV) and high volume (HV) plasma exchange (PLEX) as effective therapeutic modalities for patients with ALF. However, no studies have compared the safety and efficacy of SV with HV PLEX, which we aimed to assess.

Methods

This retrospective study included patients with ALF admitted between March 2021 and March 2023 who underwent PLEX. All patients underwent HV PLEX until May 2022, and then thereafter, SV PLEX was performed. The objectives of the study were to compare transplant-free survival (TFS) at 30 days, efficacy in reducing severity scores, biochemical variables, and adverse events between SV (total plasma volume x 1) and HV (total plasma volume x 1.5-2) PLEX.

Results

Forty two ALF patients (median age: 23.5 years; females: 57.1%; MELD Na: 34.67 ± 6.07; SOFA score- 5.24 ± 1.42) underwent PLEX. Of these, 22 patients underwent SV-PLEX, and 20 underwent HV-PLEX. The mean age, sex, etiology distribution, and severity scores were similar between the groups. The median number of PLEX sessions (2) was similar in both groups. On Kaplan-Meier analysis, TFS was 45.5% in SV group and 45% in HV group (P = 0.76). A comparable decline in total bilirubin, PT/INR, ammonia, and MELD Na scores was noted in both groups. The cumulative number of adverse events was similar between the HV group (77.3%) and SV group (54.5%; P = 0.12).

Conclusions

SV PLEX is safe and as effective as HV PLEX in patients with ALF. Further randomized controlled trials with a larger sample size are needed to validate these findings.

BTLA contributes to acute-on-chronic liver failure infection and mortality through CD4+ T-cell exhaustion

B- and T-lymphocyte attenuator (BTLA) levels are increased in patients with hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF). This condition is characterized by susceptibility to infection and T-cell immune exhaustion. However, whether BTLA can induce T-cell immune exhaustion and increase the risk of infection remains unclear. Here, we report that BTLA levels are significantly increased in the circulating and intrahepatic CD4+ T cells from patients with HBV-ACLF, and are positively correlated with disease severity, prognosis, and infection complications. BTLA levels were upregulated by the IL-6 and TNF signaling pathways. Antibody crosslinking of BTLA activated the PI3K-Akt pathway to inhibit the activation, proliferation, and cytokine production of CD4+ T cells while promoting their apoptosis. In contrast, BTLA knockdown promoted their activation and proliferation. BTLA-/- ACLF mice exhibited increased cytokine secretion, and reduced mortality and bacterial burden. The administration of a neutralizing anti-BTLA antibody reduced Klebsiella pneumoniae load and mortality in mice with ACLF. These data may help elucidate HBV-ACLF pathogenesis and aid in identifying novel drug targets.

Plasma exchange for acute and acute-on-chronic liver failure: A systematic review and meta-analysis

Plasma exchange (PE) is a promising therapeutic option in patients with acute liver failure (ALF) and acute-on-chronic liver failure (ACLF). However, the impact of PE on patient survival in these syndromes is unclear. We aimed to systematically investigate the use of PE in patients with ALF and ACLF compared with standard medical therapy (SMT). We searched PubMed/Embase/Cochrane databases to include all studies comparing PE versus SMT for patients ≥ 18 years of age with ALF and ACLF. Pooled risk ratios (RR) with corresponding 95% CIs were calculated by the Mantel-Haenszel method within a random-effect model. The primary outcome was 30-day survival for ACLF and ALF. Secondary outcomes were overall and 90-day survival for ALF and ACLF, respectively. Five studies, including 343 ALF patients (n = 174 PE vs. n = 169 SMT), and 20 studies, including 5,705 ACLF patients (n = 2,856 PE vs. n = 2,849 SMT), were analyzed. Compared with SMT, PE was significantly associated with higher 30-day (RR 1.41, 95% CI 1.06-1.87, p = 0.02) and overall (RR 1.35, 95% CI 1.12-1.63, p = 0.002) survival in ALF patients. In ACLF, PE was also significantly associated with higher 30-day (RR 1.36, 95% CI 1.22-1.52, p < 0.001) and 90-day (RR 1.21, 95% CI 1.10-1.34, p < 0.001) survival. On subgroup analysis of randomized controlled trials, results remained unchanged in ALF, but no differences in survival were found between PE and SMT in ACLF. In conclusion, PE is associated with improved survival in ALF and could improve survival in ACLF. PE may be considered in managing ALF and ACLF patients who are not liver transplant (LT) candidates or as a bridge to LT in otherwise eligible patients. Further randomized controlled trials are needed to confirm the survival benefit of PE in ACLF.

Therapeutic Plasma Exchange in Children With Acute and Acuteon-Chronic Liver Failure: A Single-Center Experience

OBJECTIVES

Acute liver failure is a life-threatening condition that may result in death if liver transplant is not performed. The aim of our study was to evaluate patients with acute liver failure or acute-on-chronic liver failure who were followed and treated with therapeutic plasma exchange in a pediatric intensive care unit until they achieved clinical recovery or underwent liver transplant.

MATERIALS AND METHODS

In this retrospective, singlecenter study, we included patients with acute liver failure or acute-on-chronic liver failure who received therapeutic plasma exchange between April 2020 and December 2021. Clinical findings, laboratory findings, extracorporeal therapies, Pediatric Risk of Mortality III and liver injury unit scores and pretherapy and posttherapy hepatic encephalopathy scores, Model for End-Stage Liver Disease score, and Pediatric End-Stage Liver Disease score were retrospectively analyzed.

RESULTS

Nineteen patients were included in the study. One patient was excluded because of positivity for COVID-19. The mean age of children was 62.06 months, ranging from 5 months to 16 years (12 boys, 6 girls). Thirteen patients (72.2%) had acute liver failure, and 5 patients (27.8%) had acute-on-chronic liver failure. No significant difference was shown for mean liver injury unit score (P = .673) and Pediatric Logistic Organ Dysfunction score (P = .168) between patients who died and patients who received treatment at the inpatient clinic and transplant center. However, Pediatric Risk of Mortality score and the mean Model for End-Stage Liver Disease/Pediatric End-Stage Liver Disease scores before therapeutic plasma exchange and after therapeutic plasma exchange (after 3 consecutive days of treatment) were statistically significant (P = .001 and P = .004).

CONCLUSIONS

Therapeutic plasma exchange may assist bridge to liver transplant or assist with spontaneous recovery of liver failure in pediatric patients with acute liver failure or acute-on-chronic liver failure.

Evaluating the Effect of Artificial Liver Support on Acute-on-Chronic Liver Failure Using the Quantitative Difference Algorithm: Retrospective Study

BACKGROUND

Liver failure, including acute-on-chronic liver failure (ACLF), occurs mainly in young adults and is associated with high mortality and resource costs. The prognosis evaluation is a crucial part of the ACLF treatment process and should run through the entire diagnosis process. As a recently proposed novel algorithm, the quantitative difference (QD) algorithm holds promise for enhancing the prognosis evaluation of ACLF.

OBJECTIVE

This study aims to examine whether the QD algorithm exhibits comparable or superior performance compared to the Model for End-Stage Liver Disease (MELD) in the context of prognosis evaluation.

METHODS

A total of 27 patients with ACLF were categorized into 2 groups based on their treatment preferences: the conventional treatment (n=12) and the double plasma molecular absorption system (DPMAS) with conventional treatment (n=15) groups. The prognosis evaluation was performed by the MELD and QD scoring systems.

RESULTS

A significant reduction was observed in alanine aminotransferase (P=.02), aspartate aminotransferase (P<.001), and conjugated bilirubin (P=.002), both in P values and QD value (Lτ>1.69). A significant decrease in hemoglobin (P=.01), red blood cell count (P=.01), and total bilirubin (P=.02) was observed in the DPMAS group, but this decrease was not observed in QD (Lτ≤1.69). Furthermore, there was a significant association between MELD and QD values (P<.001). Significant differences were observed between groups based on patients' treatment outcomes. Additionally, the QD algorithm can also demonstrate improvements in patient fatigue. DPMAS can reduce alanine aminotransferase, aspartate aminotransferase, and unconjugated bilirubin.

CONCLUSIONS

As a dynamic algorithm, the QD scoring system can evaluate the therapeutic effects in patients with ACLF, similar to MELD. Nevertheless, the QD scoring system surpasses the MELD by incorporating a broader range of indicators and considering patient variability.

Dysfunctions of Circulating Adaptive Immune Cells in End-Stage Liver Disease

End-stage liver disease (ESLD) from acute liver failure to compensated advanced chronic liver disease and decompensated cirrhosis at different stages (chronic decompensation, acute decompensation with or without acute-on-chronic liver failure) has high disease severity and poor patient outcome. Infection is a common complication in patients with ESLD and it is associated with a high mortality rate. Multiple mechanisms are involved in this marked susceptibility to infections, noticeably the inadequate immune response known as immune paresis, as part of cirrhosis-associated immune dysfunction (CAID). Specifically in the adaptive immune arm, lymphocyte impairments—including inadequate activation, reduced ability to secrete effector molecules and enhanced immune suppressive phenotypes—result in compromised systemic immune responses and increased risk of infections. This review summarises current knowledge of alterations in adaptive immune responsiveness and their underlying mechanisms in ESLD. Understanding these mechanisms is of crucial importance in the identification of potential therapeutic targets and applications of targeted treatments beyond antimicrobials, such as immunotherapy.

Lysophosphatidylcholines modulate immunoregulatory checkpoints in peripheral monocytes and are associated with mortality in people with acute liver failure

BACKGROUND & AIMS

Acute liver failure (ALF) is a life-threatening disease characterised by high-grade inflammation and immunoparesis, which is associated with a high incidence of death from sepsis. Herein, we aimed to describe the metabolic dysregulation in ALF and determine whether systemic immune responses are modulated via the lysophosphatidylcholine (LPC)-autotaxin (ATX)-lysophosphatidylcholinic acid (LPA) pathway.

METHODS

Ninety-six individuals with ALF, 104 with cirrhosis, 31 with sepsis and 71 healthy controls (HCs) were recruited. Pathways of interest were identified by multivariate statistical analysis of proton nuclear magnetic resonance spectroscopy and untargeted ultraperformance liquid chromatography-mass spectrometry-based lipidomics. A targeted metabolomics panel was used for validation. Peripheral blood mononuclear cells were cultured with LPA 16:0, 18:0, 18:1, and their immune checkpoint surface expression was assessed by flow cytometry. Transcript-level expression of the LPA receptor (LPAR) in monocytes was investigated and the effect of LPAR antagonism was also examined in vitro.

RESULTS

LPC 16:0 was highly discriminant between ALF and HC. There was an increase in ATX and LPA in individuals with ALF compared to HCs and those with sepsis. LPCs 16:0, 18:0 and 18:1 were reduced in individuals with ALF and were associated with a poor prognosis. Treatment of monocytes with LPA 16:0 increased their PD-L1 expression and reduced CD155, CD163, MerTK levels, without affecting immune checkpoints on T and NK/CD56+T cells. LPAR1 and 3 antagonism in culture reversed the effect of LPA on monocyte expression of MerTK and CD163. MerTK and CD163, but not LPAR genes, were differentially expressed and upregulated in monocytes from individuals with ALF compared to controls.

CONCLUSION

Reduced LPC levels are biomarkers of poor prognosis in individuals with ALF. The LPC-ATX-LPA axis appears to modulate innate immune response in ALF via LPAR1 and LPAR3. Further investigations are required to identify novel therapeutic agents targeting these receptors.

IMPACT AND IMPLICATIONS

We identified a metabolic signature of acute liver failure (ALF) and investigated the immunometabolic role of the lysophosphatidylcholine-autotaxin-lysophosphatidylcholinic acid pathway, with the aim of finding a mechanistic explanation for monocyte behaviour and identifying possible therapeutic targets (to modulate the systemic immune response in ALF). At present, no selective immune-based therapies exist. We were able to modulate the phenotype of monocytes in vitro and aim to extend these findings to murine models of ALF as a next step. Future therapies may be based on metabolic modulation; thus, the role of specific lipids in this pathway require elucidation and the relative merits of autotaxin inhibition, lysophosphatidylcholinic acid receptor blockade or lipid-based therapies need to be determined. Our findings begin to bridge this knowledge gap and the methods used herein could be useful in identifying therapeutic targets as part of an experimental medicine approach.

Granulocytic myeloid-derived suppressor cells increase infection risk via the IDO/IL-10 pathway in patients with hepatitis B virus-related liver failure

Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) results in high susceptibility to infection. Although granulocytic myeloid-derived suppressor cells (gMDSC) are elevated in patients with HBV-ACLF, their role in HBV-ACLF pathogenesis is unknown. To elucidate the mechanism of gMDSC expansion and susceptibility to infection in HBV-ACLF patients, we analyzed the proportion of gMDSC in the peripheral blood and organ tissues of patients with HBV-ACLF and an ACLF mouse model established by continuous injection (eight times) of Concanavalin by flow cytometry and immunohistochemistry. We found that the proportion of gMDSC increased significantly in the blood and liver of patients with HBV-ACLF. This increase was positively correlated with disease severity, prognosis, and infection. gMDSC percentages were higher in peripheral blood, liver, spleen, and bone marrow than control levels in the ACLF mouse model. Immunofluorescence revealed that the gMDSC count increased in the liver of patients with HBV-ACLF as well as in the liver and spleen of ACLF mice. We further exposed peripheral blood monocyte cells from healthy donors to plasma from HBV-ACLF patients, recombinant cytokines, or their inhibitor, and found that TNF-α led to gMDSC expansion and significant upregulation of indoleamine 2, 3-dioxygenase (IDO), while blocking TNF-α signaling decreased gMDSC. Moreover, we detected proliferation and cytokine secretion of T lymphocytes when purified gMDSC was co-cultured with Pan T cells or IDO inhibitor and found that TNF-α-induced gMDSC inhibited T cell proliferation and interferon-γ production through the IDO signaling pathway. Lastly, the ability of gMDSC to phagocytose bacteria was low in patients with HBV-ACLF. Our findings elucidate HBV-ACLF pathogenesis and provide potential therapeutic targets.

The Mechanisms of Systemic Inflammatory and Immunosuppressive Acute-on-Chronic Liver Failure and Application Prospect of Single-Cell Sequencing

Acute-on-chronic liver failure (ACLF) is a complex clinical syndrome, and patients often have high short-term mortality. It occurs with intense systemic inflammation, often accompanied by a proinflammatory event (such as infection or alcoholic hepatitis), and is closely related to single or multiple organ failure. Liver inflammation begins when innate immune cells (such as Kupffer cells (KCs)) are activated by binding of pathogen-associated molecular patterns (PAMPs) from pathogenic microorganisms or damage-associated molecular patterns (DAMPs) of host origin to their pattern recognition receptors (PRRs). Activated KCs can secrete inflammatory factors as well as chemokines and recruit bone marrow-derived cells such as neutrophils and monocytes to the liver to enhance the inflammatory process. Bacterial translocation may contribute to ACLF when there are no obvious precipitating events. Immunometabolism plays an important role in the process (including mitochondrial dysfunction, amino acid metabolism, and lipid metabolism). The late stage of ACLF is mainly characterized by immunosuppression. In this process, the dysfunction of monocyte and macrophage is reflected in the downregulation of HLA-DR and upregulation of MER tyrosine kinase (MERTK), which weakens the antigen presentation function and reduces the secretion of inflammatory cytokines. We also describe the specific function of bacterial translocation and the gut-liver axis in the process of ACLF. Finally, we also describe the transcriptomics in HBV-ACLF and the recent progress of single-cell RNA sequencing as well as its potential application in the study of ACLF in the future, in order to gain a deeper understanding of ACLF in terms of single-cell gene expression.

The Dual Role of Innate Immune Response in Acetaminophen-Induced Liver Injury

Acetyl-para-aminophenol (APAP), a commonly used antipyretic analgesic, is becoming increasingly toxic to the liver, resulting in a high rate of acute hepatic failure in Europe and the United States. Excessive APAP metabolism in the liver develops an APAP-protein adduct, which causes oxidative stress, MPTP opening, and hepatic necrosis. HMGB-1, HSP, nDNA, mtDNA, uric acid, and ATP are DMAPs released during hepatic necrosis. DMAPs attach to TLR4-expressing immune cells such KCs, macrophages, and NK cells, activating them and causing them to secrete cytokines. Immune cells and their secreted cytokines have been demonstrated to have a dual function in acetaminophen-induced liver injury (AILI), with a role in either proinflammation or pro-regeneration, resulting in contradicting findings and some research confusion. Neutrophils, KCs, MoMFs, NK/NKT cells, γδT cells, DCs, and inflammasomes have pivotal roles in AILI. In this review, we summarize the dual role of innate immune cells involved in AILI and illustrate how these cells initiate innate immune responses that lead to persistent inflammation and liver damage. We also discuss the contradictory findings in the literature and possible protocols for better understanding the molecular regulatory mechanisms of AILI.

Suppressor CD4+ T cells expressing HLA-G are expanded in the peripheral blood from patients with acute decompensation of cirrhosis

OBJECTIVE

Identifying components of immuneparesis, a hallmark of chronic liver failure, is crucial for our understanding of complications in cirrhosis. Various suppressor CD4⁺ T cells have been established as potent inhibitors of systemic immune activation. Here, we establish the presence, regulation and mechanism of action of a suppressive CD4⁺ T cell subset expressing human leucocyte antigen G (HLA-G) in patients with acute decompensation of cirrhosis (AD).

DESIGN

Flow cytometry was used to determine the proportion and immunophenotype of CD4⁺HLA-G⁺ T cells from peripheral blood of 20 healthy controls (HCs) and 98 patients with cirrhosis (28 with stable cirrhosis (SC), 20 with chronic decompensated cirrhosis (CD) and 50 with AD). Transcriptional and functional signatures of cell-sorted CD4⁺HLA-G⁺ cells were delineated by NanoString technology and suppression assays, respectively. The role of immunosuppressive cytokine interleukin (IL)-35 in inducing this population was investigated through in vitro blockade experiments. Immunohistochemistry (IHC) and cultures of primary human Kupffer cells (KCs) were performed to assess cellular sources of IL-35. HLA-G-mediated T cell suppression was explored using neutralising antibodies targeting co-inhibitory pathways.

RESULTS

Patients with AD were distinguished by an expansion of a CD4⁺HLA-G⁺CTLA-4⁺IL-35⁺ immunosuppressive population associated with disease severity, clinical course of AD, infectious complications and poor outcome. Transcriptomic analyses excluded the possibility that these were thymic-derived regulatory T cells. IHC analyses and in vitro cultures demonstrate that KCs represent a potent source of IL-35 which can induce the observed HLA-G⁺ phenotype. These exert cytotoxic T lymphocyte antigen-4-mediated impaired responses in T cells paralleled by an HLA-G-driven downregulation of T helper 17-related cytokines.

CONCLUSION

We have identified a cytokine-driven peripherally derived suppressive population that may contribute to immuneparesis in AD.

Current Advances of Innate and Adaptive Immunity in Acute-on-Chronic Hepatitis B Liver Failure

Abstract

Acute-on-chronic hepatitis B liver failure (ACHBLF) is a term used to define the acute deterioration of liver function that occurs in patients with chronic hepatitis B virus infection or hepatitis B virus-related liver cirrhosis. The specific pathogenesis of ACHBLF is still not completely understood. Current research has shown that an intense systemic inflammation is involved in the development of acute-on-chronic liver failure (ACLF). Meanwhile, a subsequent immune paresis over the course of ACLF favors the development of infection and sepsis. Deregulation in both the innate and adaptive immunity is the notable feature of ACLF. The dysregulated immune responses play a crucial role in disease progression and potentially drive organ failure and mortality in ACHBLF. In this review, we highlight the current knowledge of innate and adaptive immune cells in ACHBLF.

Alternating therapeutic plasma exchange (TPE) with double plasma molecular adsorption system (DPMAS) for the treatment of fulminant hepatic failure (FHF)

Alternating therapeutic plasma exchange with double plasma molecular adsorption system can rapidly remove bilirubin and ammonia and supplement the essential substance from the blood, which could be used as an effective treatment for fulminant hepatic failure.

The Clinical Value of GDF15 and Its Prospective Mechanism in Sepsis

Growth differentiation factor 15 (GDF15) is involved in the occurrence and development of many diseases, and there are few studies on its relationship with sepsis. This article aims to explore the clinical value of GDF15 in sepsis and to preliminarily explore its prospective regulatory effect on macrophage inflammation and its functions. We recruited 320 subjects (132 cases in sepsis group, 93 cases in nonsepsis group, and 95 cases in control group), then detected the serum GDF15 levels and laboratory indicators, and further investigated the correlation between GDF15 and laboratory indicators, and also analyzed the clinical value of GDF15 in sepsis diagnosis, severity assessment, and prognosis. In vitro, we used LPS to stimulate THP-1 and RAW264.7 cells to establish the inflammatory model, and detected the expression of GDF15 in the culture medium and cells under the inflammatory state. After that, we added GDF15 recombinant protein (rGDF15) pretreatment to explore its prospective regulatory effect on macrophage inflammation and its functions. The results showed that the serum GDF15 levels were significantly increased in the sepsis group, which was correlated with laboratory indexes of organ damage, coagulation indexes, inflammatory factors, and SOFA score. GDF15 also has a high AUC in the diagnosis of sepsis, which can be further improved by combining with other indicators. The dynamic monitoring of GDF15 levels can play an important role in the judgment and prognosis of sepsis. In the inflammatory state, the expression of intracellular and extracellular GDF15 increased. GDF15 can reduce the levels of cytokines, inhibit M1 polarization induced by LPS, and promote M2 polarization. Moreover, GDF15 also enhances the phagocytosis and bactericidal function of macrophages. Finally, we observed a decreased level of the phosphorylation of JAK1/STAT3 signaling pathway and the nuclear translocation of NF-κB p65 with the pretreatment of rGDF15. In summary, our study found that GDF15 has good clinical application value in sepsis and plays a protective role in the development of sepsis by regulating the functions of macrophages and inhibiting the activation of JAK1/STAT3 pathway and nuclear translocation of NF-κB p65.

Therapeutic plasma exchange in liver failure

The multi-organ failure syndrome associated with acute and acute-on-chronic liver failure (ACLF) is thought to be mediated by overwhelming systemic inflammation triggered by both microbial and non-microbial factors. Therapeutic plasma exchange (TPE) has been proven to be an efficacious therapy in autoimmune conditions and altered immunity, with more recent data supporting its use in the management of liver failure. Few therapies have been shown to improve survival in critically ill patients with liver failure who are not expected to survive until liver transplantation (LT), who are ineligible for LT or who have no access to LT. TPE has been shown to reduce the levels of inflammatory cytokines, modulate adaptive immunity with the potential to lessen the susceptibility to infections, and reduce the levels of albumin-bound and water-bound toxins in liver failure. In patients with acute liver failure, high volume TPE has been shown to reduce the vasopressor requirement and improve survival, particularly in patients not eligible for LT. Standard volume TPE has also been shown to reduce mortality in certain sub-populations of patients with ACLF. TPE may be most favorably employed as a bridge to LT in patients with ACLF. In this review, we discuss the efficacy and technical considerations of TPE in both acute and acute-on-chronic liver failure.

Safety of High-Volume Plasmapheresis in Children With Acute Liver Failure

OBJECTIVES

Paediatric acute liver failure (P-ALF) is a rare condition and is associated with a high mortality rate. Management of P-ALF aims to stabilise vital organ functions and to remove circulating toxins and provide vital plasma factors that are lacking. High-volume plasmapheresis (HVP) removes protein-bound substances and improves survival in adult ALF. It is unknown if this effect can be extrapolated to P-ALF. The aim of this study is to report the safety and feasibility of HVP in P-ALF.

METHODS

Children with P-ALF were offered HVP if bilirubin was higher than 200 μmol/L or if the aetiology was toxic hepatitis. HVP was performed with fresh frozen plasma corresponding to 10% of the body weight on a minimum of 3 consecutive days. Diagnostics, biochemical and clinical data during HVP as well as outcome data after 3 months were collected from 2012 to 2019 and retrospectively analysed.

RESULTS

Sixteen children were treated by HVP and completed at least one series of three treatment sessions with HVP. The only complication seen was an increase in pH > 7.55 in three children within the first 12 hours and was corrected with hydrochloric acid. No bleeding or septic episodes were noted during HVP. Eight children survived without liver transplantation, two survived after successful grafting and a total of six children died. The liver injury unit score between survivors with their own liver and the rest, the two groups was significantly different (P = 0.005).

CONCLUSION

HVP with fresh frozen plasma is feasible and well tolerated in children with P-ALF. No serious adverse events and no procedure-related mortality were observed.

Drug-induced-acute liver failure: A critical appraisal of the thioacetamide model for the study of hepatic encephalopathy

Hepatic encephalopathy (HE) following acute and chronic liver failure is defined as a complex of neuropsychiatric abnormalities, such as discrete personal changes, sleep disorder, forgetfulness, confusion, and decreasing the level of consciousness to coma. The use and design of suitable animal models that represent clinical features and pathological changes of HE are valuable to map the molecular mechanisms that result in HE. Among different types of animal models, thioacetamide (TAA) has been used extensively for the induction of acute liver injury and HE. This agent is not directly hepatotoxic but its metabolites induce liver injury through the induction of oxidative stress and produce systemic inflammation similar to that seen in acute HE patients. In this short review article, we shortly review the most important pathological findings in animal models of acute HE following the administration of TAA.

Association of 5-Hydroxytryptamine 3 Receptor Antagonists With the Prognosis of Liver Failure

Liver failure is a severe clinical syndrome with high mortality. 5-Hydroxytryptamine 3 receptor antagonists (5-HT3RAs) can reduce liver damage in animal models. We investigated whether 5-HT3RAs may improve the prognosis of liver failure. We analyzed the 28 and 90 days mortality of liver failure patients in relation to the use of 5-HT3RAs using data from a tertiary hospital in northwest China. According to the use of 5-HT3RAs, 419 patients with liver failure (46 acute, 93 sub-acute, 44 chronic, 236 acute on chronic) were divided into 5-HT3RA group (n = 105) and control group (n = 314). 5-HT3RAs were associated with decreased 28 days (HR 0.18, 95% CI 0.10-0.34, p < 0.001) and 90 days (HR 0.21, 95% CI 0.13-0.33, p < 0.001) mortality. After propensity score matching (PSM) (n = 67 in each group), 5-HT3RAs were still significantly associated with reduced 28 days (HR 0.10, 95%CI 0.04-0.26, p < 0.001) and 90 days (HR 0.16, 95%CI 0.08-0.31, p < 0.001) mortality. 5-HT3RA group patients had significantly higher 28 and 90 days survivals than controls both before and after PSM (all p < 0.001). This study shows that 5-HT3RAs are associated with increased survival of liver failure patients and thus may be used to treat liver failure if the findings are confirmed by additional studies.

Macrophages in Chronic Liver Failure: Diversity, Plasticity and Therapeutic Targeting

Chronic liver injury results in immune-driven progressive fibrosis, with risk of cirrhosis development and impact on morbidity and mortality. Persistent liver cell damage and death causes immune cell activation and inflammation. Patients with advanced cirrhosis additionally experience pathological bacterial translocation, exposure to microbial products and chronic engagement of the immune system. Bacterial infections have a high incidence in cirrhosis, with spontaneous bacterial peritonitis being the most common, while the subsequent systemic inflammation, organ failure and immune dysregulation increase the mortality risk. Tissue-resident and recruited macrophages play a central part in the development of inflammation and fibrosis progression. In the liver, adipose tissue, peritoneum and intestines, diverse macrophage populations exhibit great phenotypic and functional plasticity determined by their ontogeny, epigenetic programming and local microenvironment. These changes can, at different times, promote or ameliorate disease states and therefore represent potential targets for macrophage-directed therapies. In this review, we discuss the evidence for macrophage phenotypic and functional alterations in tissue compartments during the development and progression of chronic liver failure in different aetiologies and highlight the potential of macrophage modulation as a therapeutic strategy for liver disease.

PD-1 blockade improves Kupffer cell bacterial clearance in acute liver injury

Patients with acute liver failure (ALF) have systemic innate immune suppression and increased susceptibility to infections. Programmed cell death 1 (PD-1) expression by macrophages has been associated with immune suppression during sepsis and cancer. We therefore examined the role of the programmed cell death 1/programmed death ligand 1 (PD-1/PD-L1) pathway in regulating Kupffer cell (KC) inflammatory and antimicrobial responses in acetaminophen-induced (APAP-induced) acute liver injury. Using intravital imaging and flow cytometry, we found impaired KC bacterial clearance and systemic bacterial dissemination in mice with liver injury. We detected increased PD-1 and PD-L1 expression in KCs and lymphocyte subsets, respectively, during injury resolution. Gene expression profiling of PD-1⁺ KCs revealed an immune-suppressive profile and reduced pathogen responses. Compared with WT mice, PD-1–deficient mice and anti–PD-1–treated mice with liver injury showed improved KC bacterial clearance, a reduced tissue bacterial load, and protection from sepsis. Blood samples from patients with ALF revealed enhanced PD-1 and PD-L1 expression by monocytes and lymphocytes, respectively, and that soluble PD-L1 plasma levels could predict outcomes and sepsis. PD-1 in vitro blockade restored monocyte functionality. Our study describes a role for the PD-1/PD-L1 axis in suppressing KC and monocyte antimicrobial responses after liver injury and identifies anti–PD-1 immunotherapy as a strategy to reduce infection susceptibility in ALF.

Peripheral T lymphocytes predict the severity and prognosis in patients with HBV-related acute-on-chronic liver failure

BACKGROUND

Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is a life-threatening syndrome with high mortality. Biomarkers are urgently needed to predict the prognosis of HBV-ACLF. Recent evidence suggests a key role for immune system in the pathology of HBV-ACLF. Here, we analyzed the correlation between peripheral blood T lymphocytes and the severity and prognosis in HBV-ACLF patients.

METHOD

Sixty-six patients with HBV-ACLF received conventional medical treatments for 4 weeks. Twenty-five healthy subjects and 20 HBV patients were enrolled for comparison. We determined white blood cell count, lymphocytes, CD3+, CD4+ and CD8+ T cells, and CD4+CD25+ Treg cells in the blood of all subjects. Their associations with laboratory parameters before or after treatments were statistically analyzed.

RESULT

The results showed that compare normal subjects and chronic hepatitis B patients, HBV-ACLF patients had significantly increased white blood count, CD4+ T cells and decreased lymphocytes, CD3+ T cells, and Treg cells. Correlation analysis showed that white blood cell, lymphocytes, and peripheral T lymphocytes were correlated with prothrombin activity (PTA) and model for end-stage liver disease (MELD) scores. After treatment, white blood cell, lymphocytes, and peripheral T lymphocytes were also correlated with PTA and MELD scores. Additionally, total bilirubin (TBIL), alanine aminotransferase (ALT), international standard ratio (INR), MELD, and white blood cell count were potential prognostic criteria for HBV-ACLF patients.

CONCLUSION

HBV-ACLF patients had depletion and dysfunction of immune system. Changes of peripheral T lymphocytes were closely related to the pathogenesis and prognosis of disease. Our results may contribute to predict the severity of HBV-ACLF, and provide a prognosis response to improve the treatment of HBV-ACLF.

Immune Checkpoints: Novel Therapeutic Targets to Attenuate Sepsis-Induced Immunosuppression

Sepsis is a leading cause of death in intensive care units and survivors develop prolonged immunosuppression and a high incidence of recurrent infections. No definitive therapy exists to treat sepsis and physicians rely on supportive care including antibiotics, intravenous fluids, and vasopressors. With the rising incidence of antibiotic resistant microbes, it is becoming increasingly critical to discover novel therapeutics. Sepsis-induced leukocyte dysfunction and immunosuppression is recognized as an important contributor towards increased morbidity and mortality. Pre-clinical and clinical studies show that specific cell surface inhibitory immune checkpoint receptors and ligands including PD-1, PD-L1, CTLA4, BTLA, TIM3, OX40, and 2B4 play important roles in the pathophysiology of sepsis by mediating a fine balance between host immune competency and immunosuppression. Pre-clinical studies targeting the inhibitory effects of these immune checkpoints have demonstrated reversal of leukocyte dysfunction and improved host resistance of infection. Measurement of immune checkpoint expression on peripheral blood leukocytes may serve as a means of stratifying patients to direct individualized therapy. This review focuses on advances in our understanding of the role of immune checkpoints in the host response to infections, and the potential clinical application of therapeutics targeting the inhibitory immune checkpoint pathways for the management of septic patients.

Initial experience with high-volume plasma exchange in patients with acute liver failure

BACKGROUND/AIMS

High-volume plasma exchange (HVPE), defined as an exchange of 8 to 12 L per day per procedure or 15% of the ideal body weight with fresh frozen plasma, has shown promising results in improving the survival of patients with acute liver failure (ALF). However, clinical evidence is limited. The aim of this study was to report our initial experience using HVPE as a bridge treatment in patients with ALF.

METHODS

We retrospectively reviewed 32 consecutive patients awaiting liver transplantation (LT) due to ALF between 2013 and 2020 at Samsung Medical Center in Korea. HVPE has been used for patients with ALF since May 2016 at our institution.

RESULTS

During the study period, 16 patients received HVPE. After HVPE, coagulopathies (INR, 4.46 [2.32-6.02] vs 1.48 [1.33-1.76], P < .05), total bilirubin (22.6 [9.1-26.4] vs 8.9 [5.6-11.3], P < .05), alanine aminotransferase (506 [341-1963] vs 120 [88-315], P < .05), and ammonia levels (130.6 [123.7-143.8] vs 98.2 [84.2-116.5], P < .05) were improved. Improvement in the hepatic encephalopathy grade was observed in four patients. Among 16 patients who received HVPE, 12 patients were bridged to LT, and three patients recovered spontaneously. The overall survival was 94% and 69%, respectively at 30 days in patients who received and did not receive HVPE (P = .068). Among 18 patients with high chronic liver failure-sequential organ failure assessment scores (≥13), the overall survival was significantly better for those who received HVPE than for those who did not (91% vs 29%, respectively, at 30 days, P < .05).

CONCLUSIONS

Our initial clinical experience with HVPE suggests that HVPE can be a viable option in improving the outcomes of patients presenting with ALF.

Applications of Nanobiomaterials in the Therapy and Imaging of Acute Liver Failure

This review focuses on the therapeutic mechanisms, targeting strategies of various nanomaterials in acute liver failure, and recent advances of diverse nanomaterials for acute liver failure therapy, diagnosis, and imaging. This review provides an outlook on the applications of nanomaterials, especially on the new horizons in acute liver failure therapy, and inspires broader interests across various disciplines. Acute liver failure (ALF), a fatal clinical disease featured with overwhelming hepatocyte necrosis, is a grand challenge in global health. However, a satisfactory therapeutic option for curing ALF is still absent, other than liver transplantation. Nanobiomaterials are currently being developed for the diagnosis and treatment of ALF. The liver can sequester most of nanoparticles from blood circulation, which becomes an intrinsic superiority for nanobiomaterials targeting hepatic diseases. Nanobiomaterials can enhance the bioavailability of free drugs, thereby significantly improving the therapeutic effects in ALF. Nanobiomaterials can also increase the liver accumulation of therapeutic agents and enable more effective targeting of the liver or specific liver cells. In addition, stimuli-responsive, optical, or magnetic nanomaterials exhibit great potential in the therapeutical, diagnostic, and imaging applications in ALF. Therefore, therapeutic agents in combination with nanobiomaterials increase the specificity of ALF therapy, diminish adverse systemic effects, and offer a multifunctional theranostic platform. Nanobiomaterial holds excellent significance and prospects in ALF theranostics. In this review, we summarize the therapeutic mechanisms and targeting strategies of various nanobiomaterials in ALF. We highlight recent developments of diverse nanomedicines for ALF therapy, diagnosis, and imaging. Furthermore, the challenges and future perspectives in the theranostics of ALF are also discussed.

Effect of artificial liver support system on short-term prognosis of patients with hepatitis B virus-related acute-on-chronic liver failure

Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is difficult to treat and carries a high risk of short-term mortality. This study aimed to explore the effect of artificial liver support system (ALSS) on the survival of HBV-ACLF patients and to investigate which HBV-ACLF patients may benefit from ALSS treatment. We enrolled 132 patients hospitalized for HBV-ACLF according to the criteria of the Chinese Group on the Study of Severe Hepatitis B-ACLF (COSSH-ACLF) from 425 ACLF patients who were determined to at least meet the Asian Pacific Association for the Study of the Liver criteria and followed up for 90 days. Overall 132 eligible patients were divided into two groups: standard medical treatment (SMT) group, which included 54 patients who underwent SMT alone, and ALSS group, which included 78 patients who underwent ALSS treatment plus SMT. The proportion of HBV-ACLF grade 1, 2, and 3 was 57.69%, 37.18%, and 5.13% in the ALSS group and 51.85%, 35.19%, and 12.96% in the SMT group, respectively. Bacterial infection was present in 43.6% of patients in the ALSS group and in 55.6% of patients in the SMT group. The mortality rates in the ALSS group at 28 and 90 days were significantly lower than those in the SMT group (23.08% vs. 48.15% and 33.33% vs. 57.41%, P < 0.05). ALSS was an independent factor related to both the 28- and 90-day survival of HBV-ACLF patients. Particularly, a higher cumulative survival rate in either patients with HBV-ACLF grade 1 or those with HBV-ACLF with bacterial infection was observed in the ALSS group. Moreover, ALSS had an independent influence on mortality. Based on the COSSH-ACLF criteria, ALSS could better improve the short-term survival of HBV-ACLF patients than SMT alone, especially in those with HBV-ACLF grade 1 or HBV-ACLF with infection.

Check Point Inhibitors and Their Role in Immunosuppression in Sepsis

Checkpoint regulators are a group of membrane-bound receptors or ligands expressed on immune cells to regulate the immune cell response to antigen presentation and other immune stimuli, such as cytokines, chemokines, and complement. In the context of profound immune activation, such as sepsis, the immune system can be rendered anergic by these receptors to prevent excessive inflammation and tissue damage. If this septic immunosuppression is prolonged, the host is unable to mount the appropriate immune response to a secondary insult or infection. This article describes the manner in which major regulators in the B7-CD28 family and their ligands mediate immunosuppression in sepsis.

CD8+T cells from patients with cirrhosis display a phenotype that may contribute to cirrhosis-associated immune dysfunction

BACKGROUND

Cirrhosis-associated immune dysfunction (CAID) contributes to high sepsis risk in patients with chronic liver disease. Various innate and; to a lesser extent; adaptive immune dysfunctions have been described as contributors to CAID leading to immune-paresis and impaired anti-microbial response in cirrhosis. In this study, we examined the phenotype of CD8⁺T cells in chronic liver disease with the aim to evaluate changes that might contribute to impaired immune responses.

METHODS

Sixty patients with cirrhosis were prospectively recruited for this study. CD8⁺T cells from peripheral blood, ascites and liver explants were characterized using flow cytometry and immunohistochemistry, respectively. The transcriptional signature of flow-sorted HLA-DR⁺CD8⁺T cells was performed using Nanostring™ technology. HLA-DR⁺CD8⁺T cells interactions with PBMCs and myeloid cells were tested in vitro.

FINDINGS

Peripheral CD8⁺T cells from cirrhotic patients displayed an altered phenotype characterized by high HLA-DR and TIM-3 surface expression associated with concomitant infections and disease severity, respectively. Paired peritoneal CD8⁺T cells expressed more pronounced levels of HLA-DR and PD-1 compared to peripheral CD8⁺T cells. HLA-DR⁺CD8⁺T cells were enriched in cirrhotic livers compared to controls. TIM-3, CTLA-4 and PD-1 levels were highly expressed on HLA-DR⁺CD8⁺T cells and co-expression of HLA-DR and PD1 was higher in patients with poor disease outcomes. Genes involved in cytokines production and intracellular signalling pathways were strongly down-regulated in HLA-DR⁺CD8⁺T cells. In comparison to their HLA-DR^- counterparts, HLA-DR⁺CD8⁺T cells promoted less proliferation of PBMCs and induced phenotypic and functional dysfunctions in monocytes and neutrophils in vitro.

INTERPRETATION

In patients with cirrhosis, CD8⁺T cells display a phenotypic, functional and transcriptional profile which may contribute to CAID. FUND: This work was supported by Medical Research Council, the Rosetrees Charitable Trust, Robert Tournut 2016 grant (Sociéte Nationale Française de GastroEntérologie), Gilead® sciences, and NIHR Imperial Biomedical Research Centre.

CD8+T cells from patients with cirrhosis display a phenotype that may contribute to cirrhosis-associated immune dysfunction

BACKGROUND

Cirrhosis-associated immune dysfunction (CAID) contributes to high sepsis risk in patients with chronic liver disease. Various innate and; to a lesser extent; adaptive immune dysfunctions have been described as contributors to CAID leading to immune-paresis and impaired anti-microbial response in cirrhosis. In this study, we examined the phenotype of CD8+T cells in chronic liver disease with the aim to evaluate changes that might contribute to impaired immune responses.

METHODS

Sixty patients with cirrhosis were prospectively recruited for this study. CD8+T cells from peripheral blood, ascites and liver explants were characterized using flow cytometry and immunohistochemistry, respectively. The transcriptional signature of flow-sorted HLA-DR+CD8+T cells was performed using Nanostring™ technology. HLA-DR+CD8+T cells interactions with PBMCs and myeloid cells were tested in vitro.

FINDINGS

Peripheral CD8+T cells from cirrhotic patients displayed an altered phenotype characterized by high HLA-DR and TIM-3 surface expression associated with concomitant infections and disease severity, respectively. Paired peritoneal CD8+T cells expressed more pronounced levels of HLA-DR and PD-1 compared to peripheral CD8+T cells. HLA-DR+CD8+T cells were enriched in cirrhotic livers compared to controls. TIM-3, CTLA-4 and PD-1 levels were highly expressed on HLA-DR+CD8+T cells and co-expression of HLA-DR and PD1 was higher in patients with poor disease outcomes. Genes involved in cytokines production and intracellular signalling pathways were strongly down-regulated in HLA-DR+CD8+T cells. In comparison to their HLA-DR- counterparts, HLA-DR+CD8+T cells promoted less proliferation of PBMCs and induced phenotypic and functional dysfunctions in monocytes and neutrophils in vitro.

INTERPRETATION

In patients with cirrhosis, CD8+T cells display a phenotypic, functional and transcriptional profile which may contribute to CAID. FUND: This work was supported by Medical Research Council, the Rosetrees Charitable Trust, Robert Tournut 2016 grant (Sociéte Nationale Française de GastroEntérologie), Gilead® sciences, and NIHR Imperial Biomedical Research Centre.

Acute kidney injury spectrum in patients with chronic liver disease: Where do we stand?

Acute kidney injury (AKI) is a common complication of liver cirrhosis and is of the utmost clinical and prognostic relevance. Patients with cirrhosis, especially decompensated cirrhosis, are more prone to develop AKI than those without cirrhosis. The hepatorenal syndrome type of AKI (HRS–AKI), a spectrum of disorders in prerenal chronic liver disease, and acute tubular necrosis (ATN) are the two most common causes of AKI in patients with chronic liver disease and cirrhosis. Differentiating these conditions is essential due to the differences in treatment. Prerenal AKI, a more benign disorder, responds well to plasma volume expansion, while ATN requires more specific renal support and is associated with substantial mortality. HRS–AKI is a facet of these two conditions, which are characterized by a dysregulation of the immune response. Recently, there has been progress in better defining this clinical entity, and studies have begun to address optimal care. The present review synopsizes the current diagnostic criteria, pathophysiology, and treatment modalities of HRS–AKI and as well as AKI in other chronic liver diseases (non-HRS–AKI) so that early recognition of HRS–AKI and the appropriate management can be established.

The Beneficial Roles of SIRT1 in Drug-Induced Liver Injury

Drug-induced liver injury (DILI) is a major cause of acute liver failure (ALF) as a result of accumulated drugs in the human body metabolized into toxic agents and helps generate heavy oxidative stress, inflammation, and apoptosis, which induces necrosis in hepatocytes and ultimately damages the liver. Sirtuin 1 (SIRT1) is said to have multiple vital roles in cell proliferation, aging, and antistress systems of the human body. The levels of SIRT1 and its activation precisely modulate its critical role in the interaction between multiple step procedures of DILI. The nuclear factor kappa-light-chain-enhancer of activated B cell- (NF-κB-) mediated inflammation signaling pathway, reactive oxygen species (ROS), DNA damage, mitochondrial membrane potential collapse, and endoplasmic reticulum (ER) stress also contribute to aggravate DILI. Apoptosis is regarded as the terminal reaction followed by multiple signaling cascades including caspases, p53, and mitochondrial dysfunction which have been said to contribute in DILI. The SIRT1 activator is regarded as a potential candidate for DILI, because the former could inhibit signaling of p53, NF-κB, and ER stress. On the other hand, overexpression of SIRT1 also enhances the activation of antioxidant responses via Kelch-like ECH-associated protein 1- (Keap1-) nuclear factor- (erythroid-derived 2-) like 2 (Nrf2) signaling. The current manuscript will highlight the mechanism of DILI and the interaction of SIRT1 with various cytoplasmic factors leading to DILI along with the summary of potent SIRT1 agonists.

The Role of Monocytes and Macrophages in Acute and Acute-on-Chronic Liver Failure

Acute and acute-on-chronic liver failure (ALF and ACLF), though distinct clinical entities, are considered syndromes of innate immune dysfunction. Patients with ALF and ACLF display evidence of a pro-inflammatory state with local liver inflammation, features of systemic inflammatory response syndrome (SIRS) and vascular endothelial dysfunction that drive progression to multi-organ failure. In an apparent paradox, these patients are concurrently immunosuppressed, exhibiting acquired immune defects that render them highly susceptible to infections. This paradigm of tissue injury succeeded by immunosuppression is seen in other inflammatory conditions such as sepsis, which share poor outcomes and infective complications that account for high morbidity and mortality. Monocyte and macrophage dysfunction are central to disease progression of ALF and ACLF. Activation of liver-resident macrophages (Kupffer cells) by pathogen and damage associated molecular patterns leads to the recruitment of innate effector cells to the injured liver. Early monocyte infiltration may contribute to local tissue destruction during the propagation phase and results in secretion of pro-inflammatory cytokines that drive SIRS. In the hepatic microenvironment, recruited monocytes mature into macrophages following local reprogramming so as to promote resolution responses in a drive to maintain tissue integrity. Intra-hepatic events may affect circulating monocytes through spill over of soluble mediators and exposure to apoptotic cell debris during passage through the liver. Hence, peripheral monocytes show numerous acquired defects in acute liver failure syndromes that impair their anti-microbial programmes and contribute to enhanced susceptibility to sepsis. This review will highlight the cellular and molecular mechanisms by which monocytes and macrophages contribute to the pathophysiology of ALF and ACLF, considering both hepatic inflammation and systemic immunosuppression. We identify areas for further research and potential targets for immune-based therapies to treat these devastating conditions.

Identification of Differentially Expressed Non-coding RNA in Porcine Alveolar Macrophages from Tongcheng and Large White Pigs Responded to PRRSV

Porcine reproductive and respiratory syndrome (PRRS) is one of the most ruinous diseases in pig production. Our previous work showed that Tongcheng pigs (TC) were less susceptible to PRRS virus (PRRSV) than Large White (LW) pigs. To elucidate the difference in PRRSV resistance between the two breeds, small RNA-seq and ribo-zero RNA-seq were used to identify differentially expressed non-coding RNAs (including miRNAs and lincRNAs) responded to PRRSV in porcine alveolar macrophages (PAMs) from TC and LW pigs. Totally, 250 known mature miRNAs were detected. For LW pigs, there were 44 down-regulated and 67 up-regulated miRNAs in infection group; while for TC pigs, 12 down-regulated and 23 up-regulated miRNAs in TC infection group were identified. The target genes of the common differentially expressed miRNAs (DEmiRNAs) in these two breeds were enriched in immune-related processes, including apoptosis process, inflammatory response, T cell receptor signaling pathway and so on. In addition, 5 shared DEmiRNAs (miR-181, miR-1343, miR-296-3p, miR-199a-3p and miR-34c) were predicted to target PRRSV receptors, of which miR-199a-3p was validated to inhibit the expression of CD151. Interestingly, miR-378 and miR-10a-5p, which could inhibit PRRSV replication, displayed higher expression level in TC control group than that in LW control group. Contrarily, miR-145-5p and miR-328, which were specifically down-regulated in LW pigs, could target inhibitory immunoreceptors and may involve in immunosuppression caused by PRRSV. This indicates that DEmiRNAs are involved in the regulation of the immunosuppression and immune escape of the two breeds. Furthermore, we identified 616 lincRNA transcripts, of which 48 and 30 lincRNAs were differentially expressed in LW and TC pigs, respectively. LincRNA TCONS_00125566 may play an important role in the entire regulatory network, and was predicted to regulate the expression of immune-related genes through binding with miR-1343 competitively. In conclusion, this study provides an important resource for further revealing the interaction between host and virus, which will specify a new direction for anti-PRRSV research.

Response of regulatory T cells to classic heat stroke in mice

Systemic inflammatory response syndrome (SIRS) is an important process associated with the pathogenesis of multiple organ failure resulting from heat stroke (HS). Alterations in the levels of circulating cytokines during the progression of SIRS have been well established. However, only a small number of studies have demonstrated the responses of lymphocytes during HS, and no studies have investigated immune-regulatory cells, such as regulatory T cells (Tregs). Tregs have been revealed to be important in numerous inflammation-associated diseases, and have exhibited promising therapeutic effects in both experimental and clinical trials. In the present study, the splenic Treg response in a classic HS mouse model was investigated, and the results demonstrated that total numbers of splenic Tregs were significantly decreased at 0, 24 and 72 h time intervals post-heat stress. Furthermore, the immunosuppressive capacity of splenic Tregs on cluster of differentiation (CD)4⁺T cell expansion was revealed to be suppressed following heat stress. In addition, HS was demonstrated to downregulate the expression levels of surface inhibitory molecules (CD39, CD73 and cytotoxic T-lymphocyte associated protein 4), as well as anti-inflammatory cytokines [interleukin (IL)-10, transforming growth factor-β and IL-35], in Tregs. It was hypothesized that the aforementioned Treg responses may contribute to SIRS during HS. To the best of our knowledge, the present study is the first study to investigate the response of Tregs to HS, and the results demonstrated that there were significant alterations regarding to the total number, and function, of splenic Tregs, as well as the expression levels of inhibitory surface molecules and secretory cytokines. These results may highlight a novel mechanism underlying the pathogenesis of HS, as well as identify a potential therapeutic target for SIRS in patients suffering from HS.

Prognostic factors and treatment effect of standard-volume plasma exchange for acute and acute-on-chronic liver failure: A single-center retrospective study

Patients with acute liver failure (ALF) and acute-on-chronic liver failure (ACLF) have a high risk of mortality. Few studies have reported prognostic factors for patients receiving plasma exchange (PE) for liver support. We conducted a retrospective analysis using data of 55 patients with severe ACLF (n = 45) and ALF (n = 10) who received standard-volume PE (1-1.5 plasma volume) in the ICU. Hepatitis B virus infection accounts for the majority of ACLF (87%) and ALF (50%) patients. PE significantly improved the levels of total bilirubin, prothrombin time and liver enzymes (P<0.05). Thirteen ACLF patients (29%) and one ALF patient (10%) underwent liver transplantation. Two ALF patients (20%) recovered spontaneously without transplantation. The overall in-hospital survival rates for ACLF and ALF patients were 24% and 30%, and the transplant-free survival rates were 0% and 20%, respectively. For the 14 transplanted patients, the one-year survival rate was 86%. Multivariate analysis showed that pre-PE hemoglobin (P = 0.008), post-PE hemoglobin (P = 0.039), and post-PE CLIF-C ACLF scores (P = 0.061) were independent predictors of survival in ACLF. The post-PE CLIF-C ACLF scores ≥59 were a discriminator predicting the in-hospital mortality (area under the curve = 0.719, P = 0.030). Cumulative survival rates differed significantly between patients with CLIF-C ACLF scores ≤ 58 and those with CLIF-C ACLF scores ≥ 59 after PE (P< 0.05). The findings suggest that PE is mainly a bridge for liver transplantation and spontaneous recovery is exceptional even in patients treated with PE. A higher improvement in the post-PE CLIF-C ACLF score is associated with a superior in-hospital survival rate.

Acute-on-chronic liver failure in chronic hepatitis B: an update

Acute-on-chronic liver failure is a common pattern of end-stage liver disease in clinical practice and occurs frequently in patients with chronic hepatitis B or HBV-related cirrhosis. New progress in recent years leads to a better understanding of this disease. Areas covered: This review updates the current comprehensive knowledge about HBV-ACLF from epidemiological studies, experimental studies, and clinical studies and provide new insights into the definition, diagnostic criteria, epidemiology, nature history, pathogenesis, treatment and prognostication of HBV-ACLF. Expert commentary: Patients with chronic hepatitis B or HBV-related cirrhosis are at risk of developing acute-on-chronic liver failure, with multi-organ failure and high short-term mortality. The precipitating events can be intra-hepatic or extra-hepatic and the underlying chronic liver injury can be cirrhotic or non-cirrhotic. Host and viral factors contribute to the susceptibility of developing HBV-ACLF. Systemic inflammation is the driver of HBV-ACLF, which can be attributed to non-sterile and sterile factors. Liver transplantation is the definitive treatment for HBV-ACLF. Cell therapy is a promising alternative to LT, but requires validation and still has concern of long-term safety. Other medical therapies, such as nucleoside analogue, artificial liver supporting and glucocorticoid may improve survival in a specific subgroup. New scoring systems improve the accuracy of prognostication in HBV-ACLF, which is critical for early identification of candidates for LT.