Future directions in acute liver failure

Sepsis in liver failure patients: Diagnostic challenges and recent advancements

Acute liver failure (ALF) and acute-on-chronic LF (ACLF) are prevalent hepatic emergencies characterized by an increased susceptibility to bacterial infections (BI), despite significant systemic inflammation. Literature indicates that 30%–80% of ALF patients and 55%–81% of ACLF patients develop BI, attributed to immunological dysregulation. Bacterial sepsis in these patients is associated with adverse clinical outcomes, including prolonged hospitalization and increased mortality. Early detection of bacterial sepsis is critical; however, distinguishing between sterile systemic inflammation and sepsis poses a significant challenge due to the overlapping clinical presentations of LF and sepsis. Conventional sepsis biomarkers, such as procalcitonin and C-reactive protein, have shown limited utility in LF patients due to inconsistent results. In contrast, novel biomarkers like presepsin and sTREM-1 have demonstrated promising discriminatory performance in this population, pending further validation. Moreover, emerging research highlights the potential of machine learning-based approaches to enhance sepsis detection and characterization. Although preliminary findings are encouraging, further studies are necessary to validate these results across diverse patient cohorts, including those with LF. This article provides a comprehensive review of the magnitude, impact, and diagnostic challenges associated with BI in LF patients, focusing on novel advancements in early sepsis detection and characterization.

Expanding the horizons of bicyclol in multiple diseases: Mechanisms, therapeutic implications and challenges

Bicyclol, a drug stemmed from the traditional Chinese medicine Schisandra chinensis, has been widely utilized in clinical practice due to its efficacy and safety to manage hepatopathy. Its diverse biological properties-including antiviral, anti-inflammatory, antifibrotic, immunomodulatory, antioxidative, antisteatotic, and antitumor effects-underscore its significant medicinal effects in versatile hepatic disorders, incorporating viral hepatitis, non-alcoholic fatty liver disease, hepatocellular carcinoma, acute hepatic failure, hepatic fibrosis as well as drug-induced liver injury. Furthermore, ongoing researches into the molecular mechanisms, biological activities and mode of actions concerning bicyclol have uncovered its potential therapeutic implications in other multiple diseases/conditions. Studies have indicated promising efficacy pertaining to bicyclol to treat idiopathic pulmonary fibrosis, acute lung injury, cerebral ischemia/reperfusion injury, renal dysfunction, renal cell carcinoma, and cardiovascular diseases. Accordingly, this narrative review article summarizes the current understanding of diverse biological activities and underpinning mechanisms of bicyclol across a range of diseases, as well as its pharmacokinetics, toxicity profile and shed light on future perspectives.

Epidemiology and Risk Determinants of Drug-Induced Liver Injury: Current Knowledge and Future Research Needs

AIMS

Drug-induced liver injury (DILI) is a major global health concern resulting from adverse reactions to medications, supplements or herbal medicines. The relevance of DILI has grown with an aging population, the rising prevalence of chronic diseases and the increased use of biologics, including checkpoint inhibitors. This article aims to summarise current knowledge on DILI epidemiology and risk factors.

METHODS

This review critically appraises available evidence on DILI frequency, outcomes and risk determinants, focusing on drug properties and non-genetic host factors that may influence susceptibility.

RESULTS

DILI incidence varies across populations, with hospitalised patients experiencing notably higher rates than outpatients or the general population. Increased medication use, particularly among older adults and women, may partly explain age- and sex-based disparities in DILI incidence and reporting. Physiological changes associated with aging likely increase susceptibility to DILI in older adults, though further exposure-based studies are needed for definitive conclusions. Current evidence does not strongly support that women are inherently more susceptible to DILI than men; rather, susceptibility appears to depend on specific drugs. However, once DILI occurs, older age and female sex are associated with greater severity and poorer outcomes. Other less-studied host-related risk factors are also discussed based on available evidence.

CONCLUSIONS

This article summarises existing data on DILI frequency, outcomes, drug properties affecting hepatotoxicity and non-genetic host risk factors while identifying critical knowledge gaps. Addressing these gaps through future research could enhance understanding and support preventive measures.

Semaphorin 7a is protective through immune modulation during acetaminophen-induced liver injury

BACKGROUND AND AIM

Acetaminophen (APAP) induced acute liver injury (ALI), the leading cause acute liver failure in the western world, has limited treatment options. APAP toxicity results in massive hepatic necrosis and secondary infiltrating monocytes and neutrophils, which contribute to pathogenesis. Semaphorin 7a (Sema7a), a chemoattractant and modulator of monocytes and neutrophils, is a potential therapeutic target in other conditions, but its role in APAP-ALI is unexplored.

METHODS

Wild-type (WT) and Sema7a knockout (KO) mice were examined during APAP-ALI. Serum liver function tests, histological analysis and cellular localisation of Sema7a and its receptors, Plexin C1 and Integrin β1, were examined. Serum cytokines were quantified, tissue macrophages and neutrophils were localised, and in vivo phenotype, including phagocytosis, was assessed by immunohistochemistry and flow cytometry.

RESULTS

Sema7a was expressed by HNF4α + peri-necrotic hepatocytes circumferentially during APAP-ALI injury phases, and serum concentrations were increased, and correlated with hepatic injury. Sema7a KO mice had increased circulating inflammatory cytokines and significantly less hepatic F4/80 + macrophages, a cell type required for hepatic repair. Sema7a KO mice had higher necrotic area neutrophils, and increased neutrophil chemoattractant CXCL1. Without Sema7a expression, mice displayed increased necrosis and liver injury markers compared to Sema7a WT mice. Without peri-necrotic hepatocyte Sema7a expression, we also identified increased cell death and hepatic cellular stress outside of necrosis.

CONCLUSION

We have identified a novel protective role of Sema7a during injury phases of APAP-ALI. Without peri-necrotic hepatocyte Sema7a expression and secretion, there is increased inflammation, time specific worsened hepatic necrosis and increased hepatic cell stress and death outside of the necrotic zone.

Cell therapy for liver disorders: past, present and future

The liver fulfils a plethora of vital functions and, due to their importance, liver dysfunction has life-threatening consequences. Liver disorders currently account for more than two million deaths annually worldwide and can be classified broadly into three groups, considering their onset and aetiology, as acute liver diseases, inherited metabolic disorders and chronic liver diseases. In the most advanced and severe forms leading to liver failure, liver transplantation is the only treatment available, which has many associated drawbacks, including a shortage of organ donors. Cell therapy via fully mature cell transplantation is an advantageous alternative that may be able to restore a damaged organ's functionality or serve as a bridge until regeneration can occur. Pioneering work has shown that transplanting adult hepatocytes can support liver recovery. However, primary hepatocytes cannot be grown extensively in vitro as they rapidly lose their metabolic activity. Therefore, different cell sources are currently being tested as alternatives to primary cells. Human pluripotent stem cell-derived cells, chemically induced liver progenitors, or 'liver' organoids, hold great promise for developing new cell therapies for acute and chronic liver diseases. This Review focuses on the advantages and drawbacks of distinct cell sources and the relative strategies to address different therapeutic needs in distinct liver diseases.

Network pharmacology and experimental validation reveal dexmedetomidine's protective mechanisms against acute liver injury in mice

This study explored the role and molecular mechanisms of dexmedetomidine (DEX), an α2-adrenergic receptor agonist, in the treatment of a mouse model of acute liver injury (ALI). DEX significantly mitigated hepatic tissue damage and reduced serum levels of liver function biomarkers and proinflammatory cytokines. Network pharmacology analysis revealed 81 common targets between DEX and ALI, identifying 10 crucial hub genes. Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated that DEX's therapeutic effect on ALI is likely linked to the activation of the PI3K/AKT pathway. Immunohistochemical experiments verified DEX's activation of the PI3K/AKT pathway. Molecular docking and dynamic simulations confirmed the stable interaction between DEX and the epidermal growth factor receptor (EGFR). Immunohistochemistry and western blotting further validated that DEX pretreatment upregulated EGFR expression. Our findings indicate that DEX may mitigate ALI by interacting with EGFR and triggering the PI3K/AKT pathway. These findings provide a solid theoretical and experimental basis for using DEX as a potential therapeutic regimen for treating inflammatory liver diseases.

Bioinspired Spatially Ordered Multicellular Lobules for Liver Regeneration

Cell therapy is a promising strategy for acute liver failure (ALF), while its therapeutic efficacy is often limited by cell loss and poor arrangement. Here, inspired by liver microunits, we propose a novel spatially ordered multicellular lobules for the ALF treatment by using a microfluidic continuous spinning technology. The microfluidics with multiple microchannels was constructed by assembling parallel capillaries. Sodium alginate (Alg) solution encapsulating human umbilical vein endothelial cells (HUVECs), hepatocytes, and mesenchymal stem cells (MSCs) are introduced into the middle channel and the 6 parallel outer channels of the microfluidics, respectively. Simultaneously, Ca2+-loaded solutions are pumped through the innermost and outermost channels, forming a hollow microfiber with hepatocytes and MSCs alternately surrounding the HUVECs. These microfibers could highly resemble the cord-like structure of liver lobules, bringing about outstanding liver-like functions. We have demonstrated that in ALF rats, our biomimetic lobules can effectively suppress excessive inflammatory responses, decrease cell necrosis, and promote regenerative pathways, leading to satisfied therapeutic efficacy. These findings underscore the potential of spatially ordered multicellular microfibers in treating related diseases and improving traditional clinical methods.

Preliminary experience of combined dual plasma molecular adsorption system and plasma exchange in pediatric acute liver failure: a retrospective case series

BACKGROUND

Pediatric acute liver failure (PALF) is a life-threatening condition with no definitive treatment. This study evaluated the combined use of the dual plasma molecular adsorption system (DPMAS) and plasma exchange (PE) to improve liver function and survival outcomes in PALF patients.

METHODS

A retrospective study was conducted on 7 PALF patients treated with DPMAS and PE. Data on liver function scores (Liver Injury Unit [LIU], Model for End-Stage Liver Disease [MELD], Model for End-Stage Liver Disease with Sodium [MELD-Na], MELD 3.0), bilirubin levels, and coagulation indices were collected before and after treatment.

RESULTS

DPMAS and PE treatments significantly reduced total bilirubin (382.2 µmol/L to 52.0 µmol/L) and improved coagulation indices. Liver injury scores decreased notably (e.g., LIU from 184 to 52 in one case). Five patients recovered, while two with severe comorbidities showed limited improvement.

CONCLUSION

The combination of DPMAS and PE therapy improves liver function and survival outcomes in PALF. These results support its use as a bridge to recovery or transplantation in PALF patients, though further studies with larger sample sizes are needed.

Merestinib inhibits cuproptosis by targeting NRF2 to alleviate acute liver injury

The emergence of cuproptosis, a novel form of regulated cell death, is induced by an excess of copper ions and has been associated with the progression of multiple diseases, including liver injury, cardiovascular disease, and neurodegenerative disorders. However, there are currently no inhibitors available for targeting specific cuproptosis-related pathways in therapy. Here, the compound merestinib (MTB) has been identified as a strong inhibitor of cuproptosis through screening of a kinase inhibitor library. The results show that MTB effectively blocks elesclomol-CuCl2 (ES-Cu) induced cuproptosis by preventing the aggregation of lipoylated proteins and the destabilization of Fe-S cluster proteins, thereby preventing proteotoxic stress and ultimately cell death. Mechanistically, MTB decreases oxidative stress levels by binding directly to NRF2. Additionally, it boosts the efficiency of the copper homeostasis and facilitates the exocytosis and transportation of copper ions, ultimately inhibiting cuproptosis. Furthermore, our research showed that MTB has the ability to alleviate cuproptosis-driven acute liver injury in mice. These findings suggest that MTB is a specific inhibitor of cuproptosis, presenting a hopeful option for therapeutic approaches in cuproptosis-related diseases.

[Acute Liver Failure]

Acute liver failure (ALF) is a severe, potentially reversible form of liver insufficiency, which is defined by the occurrence of hepatic coagulopathy and hepatic encephalopathy in patients with no previous hepatic disease. Acute liver failure is preceded by severe acute liver injury (ALI) with an increase in transaminases, jaundice, and deterioration in general condition over a period of hours to weeks. Every year 200-500 people develop ALF in Germany, most frequently on the background of toxic liver injury (e.g. drug induced liver injury). Other potential causes include viral infections (e.g. hepatitis A and B), autoimmune hepatitis, Budd-Chiari Syndrome or Wilson's disease. Patients usually present at the stage of acute liver damage. Initial diagnostics should include a detailed medical history, clinical examination, laboratory diagnostics and abdominal sonography. The course of acute liver failure is very difficult to predict, so all patients with severe acute liver damage should be evaluated for transfer to a center. At the latest when hepatic encephalopathy occurs and thus when all the definition criteria of acute liver failure are met, the patient should be transferred to a liver transplant center immediately. While specific medical therapies may be available in the early stages of the disease, depending on the etiology, the focus in advanced stages is on preventing complications and treating associated organ dysfunctions. In progressive cases, liver transplantation is often the only life-saving measure. Overall, the mortality rate in Germany is 47%, and approximately 8% of annual liver transplants in the European Union are performed due to ALF.

FNDC5/Irisin exacerbates APAP-induced acute liver injury through activating JNK/NF-κB and inflammatory response

Acute liver injury (ALI) is associated with high mortality rates. Despite its severity, there are currently no effective interventions, underscoring the urgent need for research on the mechanisms driving ALI progression. Irisin, a hormone derived from its precursor FNDC5, has been shown to play a critical role in some chronic liver diseases. In this study we investigated the role of hepatic FNDC5/Irisin in a mouse model of AILI induced by acetaminophen (APAP, 400 mg/kg, i.p.). The mice were euthanized at 6, 12 and 24 h after APAP injection, then the blood and liver tissues were collected for analyses. By conducting transcriptome sequencing, we identified that both the expression and release of FNDC5/Irisin were significantly increased and highly correlated with AILI. We showed that knockout of Irisin significantly improved APAP-induced tissue damage and hepatocyte death in mouse liver. Conversely, preinjection of recombinant Irisin protein (1 mg·kg-1·d-1, i.p., for 3 days) exacerbated the AILI in FNDC5 knockout mice. RNA-seq analysis revealed that knockout of FNDC5/Irisin reduced inflammatory responses and JNK/NF-κB activation in APAP-treated mouse liver, while exogenous Irisin administration aggravated JNK/NF-κB-mediated inflammation. In primary mouse hepatocytes treated with APAP (15 mM), application of Irisin (100 ng/mL) activated the integrin αV/JNK/NF-κB axis, driving inflammation and oxidative stress. In summary, this study highlights Irisin as a critical regulator in AILI progression. Circulating Irisin could be a novel biomarker for AILI diagnosis, and targeting FNDC5/Irisin could hold promise for the development of novel treatments for AILI.

The endothelial growth factor Angiopoietin-2 is an accurate prognostic biomarker in patients with acetaminophen-induced acute liver failure

Background and Aims

Acetaminophen (APAP) overdose is the leading individual cause of acute liver failure (ALF) in the United States, with many patients rapidly progressing to hyperacute liver failure. While hepatocytes are the main target of APAP toxicity, endothelial cells (ECs) are also affected. However, the efficacy of an endothelial-specific biomarker to predict patient outcomes remains unknown. This study aimed to evaluate angiopoietin-2 (ANGPT2) as a prognostic biomarker for poor outcomes in APAP-induced ALF.

Approach and Results

Using human and mouse single-cell RNA sequencing (scRNAseq) data, we found that ANGPT2 expression was significantly elevated in ECs following APAP exposure. We measured circulating ANGPT2 levels from two independent APAP-ALF cohorts: a Phoenix cohort (n=43) and a cohort from the ALF Study Group (n=80). In the Phoenix cohort, ANGPT2 levels were significantly higher in non-survivors with an AUROC of 0.938. In the ALFSG cohort, we stratified patients based on time of symptom onset finding that ANGPT2 had improved prognostic value in early-presenting patients, with day 1 and day 3 AUC values of 0.825 and 0.918, respectively. Lastly, we combined the patient cohorts (n=110) finding that ANGPT2 alone or in combination with MELD outperformed MELD alone based on AUC (ANGPT2: 0.87, MELD 0.83, ANGPT2+MELD 0.90).

Conclusions

ANGPT2 is a promising prognostic biomarker for APAP-induced ALF, reflecting endothelial stress and offering superior predictive value compared to MELD alone, especially in early-presenting patients. Its capacity for predicting poor outcomes underscores its value in improving patient prognosis and therapeutic intervention strategies in APAP overdose cases.

Lay Summary

Accidental or intentional overdosing on acetaminophen can cause liver injury and in severe cases acute liver failure. Under these circumstances, receiving a liver transplant may be the only remaining therapeutic option. However, a liver transplant is a major surgery and commits the patient to a lifetime of anti-rejection medication. Because there is only a limited time window to decide who will recover and who needs a transplant to survive, prognostic biomarkers are essential to identify transplant candidates as early as possible after the overdose. In this study we discovered that plasma levels of the endothelial growth factor angiopoietin-2 can accurately predict at the peak of injury who will need a liver transplant to survive. In addition, this biomarker can be rapidly measured, which allows the data to be available for clinical decision making.

Highlights

Acetaminophen-induced liver injury can cause hyper-acute liver failure within 3 to 7 days with a high probability of negative outcome.Under these conditions, a liver transplant may be the only therapeutic option.In two independent cohorts, angiopoietin 2 was identified as an early prognostic biomarker for poor outcome.Angiopoietin can more accurately inform clinical management during the initial stages of hospital presentation than the MELD score.

Liver diseases: epidemiology, causes, trends and predictions

As a highly complex organ with digestive, endocrine, and immune-regulatory functions, the liver is pivotal in maintaining physiological homeostasis through its roles in metabolism, detoxification, and immune response. Various factors including viruses, alcohol, metabolites, toxins, and other pathogenic agents can compromise liver function, leading to acute or chronic injury that may progress to end-stage liver diseases. While sharing common features, liver diseases exhibit distinct pathophysiological, clinical, and therapeutic profiles. Currently, liver diseases contribute to approximately 2 million deaths globally each year, imposing significant economic and social burdens worldwide. However, there is no cure for many kinds of liver diseases, partly due to a lack of thorough understanding of the development of these liver diseases. Therefore, this review provides a comprehensive examination of the epidemiology and characteristics of liver diseases, covering a spectrum from acute and chronic conditions to end-stage manifestations. We also highlight the multifaceted mechanisms underlying the initiation and progression of liver diseases, spanning molecular and cellular levels to organ networks. Additionally, this review offers updates on innovative diagnostic techniques, current treatments, and potential therapeutic targets presently under clinical evaluation. Recent advances in understanding the pathogenesis of liver diseases hold critical implications and translational value for the development of novel therapeutic strategies.

Atractylenolide I prevents acute liver failure in mouse by regulating M1 macrophage polarization

Acute liver failure (ALF) is a life-threatening clinical syndrome with a substantial risk of mortality. A murine model of lipopolysaccharide (LPS)- and D-galactosamine (D-GalN)-induced ALF is widely used to investigate the underlying mechanisms and potential therapeutic drugs for human liver failure. Atractylenolide I (ATR-I) is an active component of the Atractylodes macrocephala rhizome and possesses various pharmacological activities, including anti-tumor, anti-inflammatory, and anti-oxidant properties. Given the key role of oxidative stress and inflammation in ALF pathogenesis, this study investigates the protective effects of ATR-I on LPS/D-GalN-induced ALF in mice. The results suggest that ATR-I pretreatment significantly ameliorates ALF, as evidenced by decreased serum aminotransferase levels and prolonged mice survival. Additionally, ATR-I pretreatment inhibits oxidative stress. Furthermore, the ATR-I pretreatment markedly suppresses M1 macrophage activation in hepatic mononuclear cells. In vitro experiments with bone marrow-derived macrophages indicate that ATR-I regulates macrophage polarization through the mitogen-activated protein kinase (MAPK) and interferon regulatory factor (IRF) signaling pathways. Collectively, ATR-I pretreatment protects mice from LPS/D-GalN-induced ALF partially by regulating M1 macrophage polarization.

Stratifying and predicting progression to acute liver failure during the early phase of acute liver injury

Acute liver failure (ALF) is a serious disease that progresses from acute liver injury (ALI) and that often leads to multiorgan failure and ultimately death. Currently, effective treatment strategies for ALF, aside from transplantation, remain elusive, partly because ALI is highly heterogeneous. Furthermore, clinicians lack a quantitative indicator that they can use to predict which patients hospitalized with ALI will progress to ALF and the need for liver transplantation. In our study, we retrospectively analyzed data from 319 patients admitted to the hospital with ALI. By applying a machine-learning approach and by using the SHapley Additive exPlanations (SHAP) algorithm to analyze time-course blood test data, we identified prothrombin time activity percentage (PT%) as a biomarker reflecting individual ALI status. Unlike previous studies predicting the need for liver transplantation in patients with ALF, our study focused on PT% dynamics. Use of this variable allowed us to stratify the patients with highly heterogeneous ALI into six groups with distinct clinical courses and prognoses, i.e. self-limited, intensive care-responsive, or intensive care-refractory patterns. Notably, these groups were well predicted by clinical data collected at the time of admission. Additionally, utilizing mathematical modeling and machine learning, we assessed the predictability of individual PT% dynamics during the early phase of ALI. Our findings may allow for optimizing medical resource allocation and early introduction of tailored individualized treatment, which may result in improving ALF prognosis.

Mechanistic insights from a pilot exploratory study of the dynamic proteomic changes during plasma exchange in patients with acute liver failure

BACKGROUND & AIMS

Therapeutic plasma exchange (PEX) has shown potential in improving transplant-free survival in acute liver failure (ALF) however the mechanism of action is not understood. This exploratory study aimed to elucidate the circulating proteomic changes associated with PEX in ALF to provide insight into mechanisms underlying the benefit of this therapy.

METHODS

Consecutive patients admitted with ALF between June 2019 and August 2020 were enrolled. Patients received either standard medical treatment (n = 5) or PEX (n = 5). Plasma samples were collected at multiple time points and analysed using the Olink Proximity Extension Assay. Comparative analyses included healthy controls and Octaplas batches.

RESULTS

Biomarker results were available for 54 samples: Octaplas batches (n = 7), healthy controls (n = 6), ALF-standard medical treatment (n = 8), and ALF-PEX (n = 33). Proteomic analysis of 177 biomarkers revealed marked baseline differences between ALF and healthy controls, with ALF patients exhibiting lower levels of proteins secreted by the liver and higher levels of inflammatory cytokines and growth factors. Longitudinal analysis showed several distinct patterns with PEX. Proteins including carboxylesterase-1, hepatocyte growth factor, fetuin B, IL-6 and IL-10 showed differential expression patterns longitudinally, indicating some of the potential underlying mechanisms and therapeutic effects of PEX.

CONCLUSIONS

PEX in ALF patients leads to dynamic proteomic changes, reflecting its multifaceted role in modulating inflammation, liver regeneration and replacing essential proteins. These findings provide insight into some of the changes in circulating blood proteins and underlying mechanisms of PEX.

P2Y14R activation facilitates liver regeneration via CREB/DNMT3b/Dact-2/β-Catenin signals in acute liver failure

Acute liver failure (ALF) is lack of broadly approved therapeutic strategy except liver transplantation. As a glycogen metabolic intermediate, UDP-glucose (UDP-G) has been considered to accelerate liver repairment. Nevertheless, the role of UDP-G and its receptor P2Y purinoceptor 14 (P2Y14R) in ALF remains unknown. The present study aims to investigate the role and underlying mechanisms of UDP-G/P2Y14R axis in ALF. In this study, hepatic P2Y14R is significantly increased in TAA-induced and partial hepatectomy-induced ALF, while knockout of whole-body P2Y14R aggravates liver failure, manifested by inhibiting β-Catenin-mediated liver regeneration. Consistently, P2Y14R deficiency exhibits impaired liver regeneration in mice suffer partial hepatectomy. Importantly, only hepatocellular specific deletion of P2Y14R (P2Y14R flox/flox Alb cre/+ ) mice shows a similar phenomenon, rather than stellate cell specific deletion of P2Y14R (P2Y14R flox/flox Lrat cre/+ ) mice. Mechanistically, P2Y14R induction regulates methylation of Dact-2 through CREB/DNMT3b signals in hepatocytes, subsequently inhibiting the expression of Dact-2 which is a stabilizer of β-Catenin degradation complex, leading to the activation of β-Catenin -mediated liver regeneration. Interestingly, the administration of exogenous UDP-G can accelerate liver regeneration and liver function recovery after partial hepatectomy in hepatocellular carcinoma mice. Together, the findings propose an unrecognized role of P2Y14R in ALF and provide an effective adjuvant strategy for treatment of ALF.

Silibinin alleviates acute liver failure by modulating AKT/GSK3β/Nrf2/GPX4 pathway

Silibinin (Sil) is a major bioactive component of silymarin, extracted from the fruit and seeds of Silybum marianum. Silibinin meglumine (SM) is a water-soluble derivative of silibinin that has shown significant potential in liver fibrosis. However, the potential effects and underlying mechanisms of SM on acute liver failure (ALF) are still not fully understood. This study aims to find the likely mechanism. An ALF mouse model and a cell model were established with GalN/LPS. SM was administered to mice via the tail vein or to a hepatocyte line (alpha mouse liver 12, AML12). The results showed that SM particularly lowered the mortality and improved liver pathological lesions in ALF mice. Meanwhile, SM improved the levels of GSH, SOD, TNF-α, IL-6, IL-1β, and IL-10 in the liver tissues and serum. Additionally, SM enhanced cell viability and reduced oxidative stress in vitro. In the AKT/GSK3β/Nrf2/GPX4 pathway, the subpathway of AKT/GSK3β was inhibited, and the subpathway of Nrf2/GPX4 was activated by SM both in vivo and in vitro. In addition, ferrostatin-1, a ferroptosis inhibitor, and the silencing of AKT using siRNA weakened the protective effect of SM, indicating that this process is mediated in an AKT-dependent manner. All the results suggested that SM inhibits inflammation and oxidative stress by modulating the AKT/GSK3β/Nrf2/GPX4 pathway.

Screening of Herbs with Potential Modulation of NLRP3 Inflammasomes for Acute Liver Failure: A Study Based on the Herb-Compound-Target Network and the ssGSEA Algorithm

OBJECTIVE

NLRP3 inflammasomes are considered to be key factors in the pathogenesis of Acute Liver Failure (ALF). Some Traditional Chinese Medicines (TCMs) have shown protective and therapeutic effects against ALF by inhibiting NLRP3 inflammasomes. However, the inhibitory effects of most TCMs on ALF remain to be further elucidated. This study aimed to screen potential herbs that can treat ALF based on the inhibition of NLRP3 inflammasomes.

METHODS

Initially, we constructed the target set for 502 herbs. Subsequently, based on the target set and the gene set related to the NLRP3 inflammasome, using the ssGSEA algorithm, we evaluated herb scores and NLRP3 scores in the ALF expression matrix and performed a preliminary herb screening based on score correlations. Through bioinformatics approaches, we identified the key targets for candidate herbs and determined core herbs based on the herb-compound-target network. Furthermore, molecular docking and molecular biology methods validated the screening results of the herbs.

RESULTS

A total of 18 crucial targets associated with the inhibition of the NLRP3 inflammasome were identified, which included ALDH2, HMOX1, and VEGFA. Subsequently, based on these key targets, a set of 10 primary herbs was chosen, notably Qinghao, Duzhong, and Gouteng. Moreover, the results were verified through molecular docking and molecular dynamic simulation.

CONCLUSION

Ten key herbs have been identified as potential inhibitors of the NLRP3 inflammasome, offering insights into ALF therapy for drug development.

Cross-circulation combined with rapidly deployable venovenous bypass grafts for multiorgan biosystemic support in liver failure: experimental studies

BACKGROUND

Liver failure remains a critical clinical challenge with limited treatment options. Cross-circulation, the establishment of vascular connections between individuals, has historically been explored as a potential supportive therapy but with limited success. This study investigated the feasibility of combining cross-circulation with a rapidly deployable venovenous bypass (VVB) graft for multiorgan support in a rat model of total hepatectomy, representing the most severe form of liver failure.

MATERIALS AND METHODS

A Y-shaped VVB graft was fabricated using coaxial electrospinning of PLCL/heparin nanofibers and magnetic rings for rapid anastomosis. After total hepatectomy in rats, the VVB graft was implanted to divert blood flow. Cross-circulation was then established between anhepatic and normal host rats. Hemodynamics, biochemical parameters, blood gases, and survival were analyzed across three groups: hepatectomy with blocked vessels (block group), hepatectomy with VVB only (VVB group), and hepatectomy with VVB and cross-circulation (VVB/cross-circulation group).

RESULTS

The VVB graft exhibited suitable mechanical properties and hemocompatibility. VVB rapidly restored hemodynamic stability and mitigated abdominal congestion posthepatectomy. Cross-circulation further ameliorated liver dysfunction, metabolic derangements, and coagulation disorders in anhepatic rats, significantly prolonging survival compared to the VVB group (mean 6.56±0.58 vs. 4.05±0.51 h, P <0.05) and the block group (mean 1.01±0.05 h, P <0.05).

CONCLUSION

Combining cross-circulation with a rapidly deployed VVB graft provided effective multiorgan biosystemic support in a rat model of total hepatectomy, substantially improving the biochemical status and survival time. This approach holds promise for novel liver failure therapies and could facilitate liver transplantation procedures.

Acetylcorynoline alleviates acute liver injury via inhibiting TLR4/JNK/NF-ĸB pathway Based on RNA-seq and molecular docking in vivo and in vitro

Acute liver injury is characterized by massive inflammatory cell infiltration, destruction of liver structure and abnormalities in liver function. Acetylcorynoline (AC) is one of the main chemical components of Corydalis bungeana Turcz. which has been shown to have a protective effect against acute liver injury. However, Whether AC is protective against acute liver injury remains unclear. This study aimed to explore the protective mechanism of AC against acute liver injury from in vivo as well as experiments in vitro. In experimental in vivo studies, AC pretreatment reduced the serum levels of ALT and AST and inhibited the expression of inflammatory factors in the liver of LPS/D-GalN-induced mice and alcohol liver disease mice. RNA-sequencing and molecular docking were used to predict that AC exerts its anti-inflammatory effects through the Toll-like receptor signaling pathway. Using RT-qPCR and Western blotting to detect expression levels of key genes and nodal proteins of the Toll-like receptor signaling pathway, AC was found to inhibit the phosphorylation of nuclear factor-kappaB (NF-ĸB) and c-Jun amino-terminal kinase (JNK). This finding was validated in cellular experiments. In conclusion, AC exerts its anti-hepatic injury effect by suppressing inflammation through inhibition of the TLR4/JNK/NF-ĸB pathway.

Prognostic models in acute liver failure-historic evolution and newer updates "prognostic models in acute liver failure"

Acute liver failure (ALF) is a rare and dynamic syndrome occurring as a sequela of severe acute liver injury (ALI). Its mortality ranges from 50% to 75% based on the aetiology, patients age and severity of encephalopathy at admission. With improvement in intensive care techniques, transplant-free survival in ALF has improved over time. Timely recognition of patients who are unlikely to survive with medical intervention alone is crucial since these individuals may rapidly develop multiorgan failure and render liver transplantation futile. Various predictive models, biomarkers and AI-based models are currently used in clinical practice, each with its fallacies. The King's College Hospital criteria (KCH) were initially established in 1989 to identify patients with acute liver failure (ALF) caused by paracetamol overdose or other causes who are unlikely to improve with conventional treatment and would benefit from a liver transplant. Since then, various models have been developed and validated worldwide. Most models include age, aetiology of liver disease, encephalopathy grade, and liver injury markers like INR, lactate, factor V level, factor VIII/V ratio and serum bilirubin. But none of the currently available models are dynamic and lack accuracy in predicting transplant free survival. There is an increasing interest in developing prognostic serum biomarkers that when used alone or in combination with clinical models enhance the accuracy of predicting outcomes in ALF. Genomics, transcriptomics, proteomics, and metabolomics as well as machine learning and artificial intelligence (AI) algorithms are areas of interest for developing higher-precision predictive models. Overall, the future of prognostic models in ALF is promising, with ongoing research paving the way for more accurate, personalized, and dynamic risk assessment tools that can potentially save lives in this challenging condition. This article summarizes the history of prognostic models in ALF and future trends.

An international, multicenter, survey-based analysis of practice and management of acute liver failure

Acute liver failure (ALF) is an acute liver dysfunction with coagulopathy and HE in a patient with no known liver disease. As ALF is rare and large clinical trials are lacking, the level of evidence regarding its management is low-moderate, favoring heterogeneous clinical practice. In this international multicenter survey study, we aimed to investigate the current practice and management of patients with ALF. An online survey targeting physicians who care for patients with ALF was developed by the International Liver Transplantation Society ALF Special-Interest Group. The survey focused on the management and liver transplantation (LT) practices of ALF. Survey questions were summarized overall and by geographic region. A total of 267 physicians completed the survey, with a survey response rate of 21.36%. Centers from all continents were represented. More than 90% of physicians specialized in either transplant hepatology/surgery or anesthesiology/critical care. Two hundred fifty-two (94.4%) respondents' institutions offered LT. A total of 76.8% of respondents' centers had a dedicated liver-intensive or transplant-intensive care unit ( p < 0.001). The median time to LT was within 48 hours in 12.7% of respondents' centers, 72 hours in 35.6%, 1 week in 37.6%, and more than 1 week in 9.6% ( p < 0.001). Deceased donor liver graft (49.6%) was the most common type of graft offered. For consideration of LT, 84.8% of physicians used King's College Criteria, and 41.6% used Clichy Criteria. Significant differences were observed between Asia, Europe, and North America for offering LT, number of LTs performed, volume of patients with ALF, admission to a dedicated intensive care unit, median time to LT, type of liver graft, monitoring HE and intracranial pressure, management of coagulopathy, and utilization of different criteria for LT. In our study, we observed significant geographic differences in the practice and management of ALF. As ALF is rare, multicenter studies are valuable for identifying global practice.

Paediatric acute liver failure: a multidisciplinary perspective on when a critically ill child is unsuitable for liver transplantation

Paediatric acute liver failure is a devastating condition with high morbidity and mortality, which is challenging to manage for the hepatologist, intensivist, and associated specialists. Emergency liver transplantation is required for 10-20% of patients, but for 10% of critically ill children, liver transplantation is deemed unsuitable; the child might be too unwell, or the underlying cause might carry a poor prognosis. Other social, logistical, or ethical considerations are often relevant. Liver transplantation when a patient is too unwell creates perioperative risk to the child that could lead to morbidity, mortality, and potential graft wastage, which is detrimental for others on the waiting list. Donor liver scarcity should prompt an evaluation of whether a transplant is justified through a holistic multidisciplinary lens that considers medical, social, logistical, and ethical concerns. In this Review, we explore, from a multidisciplinary perspective, why a critically unwell child with paediatric acute liver failure might be unsuitable for liver transplantation.

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.

Outcomes of patients with acute liver failure not listed for liver transplantation: A cohort analysis

BACKGROUND

Acute liver failure (ALF) is a rare condition leading to morbidity and mortality. Liver transplantation (LT) is often required, but patients are not always listed for LT. There is a lack of data regarding outcomes in these patients. Our aim is to describe outcomes of patients with ALF not listed for LT and to compare this with those listed for LT.

METHODS

Retrospective analysis of all nonlisted patients with ALF enrolled in the Acute Liver Failure Study Group (ALFSG) registry between 1998 and 2018. The primary outcome was 21-day mortality. Multivariable logistic regression was done to identify factors associated with 21-day mortality. The comparison was then made with patients with ALF listed for LT.

RESULTS

A total of 1672 patients with ALF were not listed for LT. The median age was 41 (IQR: 30-54). Three hundred seventy-one (28.9%) patients were too sick to list. The most common etiology was acetaminophen toxicity (54.8%). Five hundred fifty-eight (35.7%) patients died at 21 days. After adjusting for relevant covariates, King's College Criteria (adjusted odds ratio: 3.17, CI 2.23-4.51), mechanical ventilation (adjusted odds ratio: 1.53, CI: 1.01-2.33), and vasopressors (adjusted odds ratio: 2.10, CI: 1.43-3.08) (p < 0.05 for all) were independently associated with 21-day mortality. Compared to listed patients, nonlisted patients had higher mortality (35.7% vs. 24.3%). Patients deemed not sick enough had greater than 95% survival, while those deemed too sick still had >30% survival.

CONCLUSIONS

Despite no LT, the majority of patients were alive at 21 days. Survival was lower in nonlisted patients. Clinicians are more accurate in deeming patients not sick enough to require LT as opposed to deeming patients too sick to survive.

Berberine attenuates ECM accumulation and the progression of acute liver failure through inhibition of NLRP3 inflammasome signalling

Acute liver failure (ALF) is a life-threatening disease, characterized by upregulated extracellular matrix deposition and inflammatory signalling, with no effective treatment options and targets. The present study was designed to investigate the preventive and therapeutic effects of berberine (BBR) and its underlying mechanism in thioacetamide (TAA)-induced ALF. Male SD rats were administered with TAA 300 mg/kg, i.p., thrice to induce ALF and pre- or post-treated with BBR. To decipher the effects of BBR LFT markers, histopathological analysis of key fibrotic and inflammatory proteins was performed. In addition, the levels of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α were assessed by ELISA. Our work showed TAA-induced ALF animals were associated with increased ALT, AST, bilirubin (LFT markers) and histopathological alterations with profuse infiltration of inflammatory cells in the liver tissue. Treatment with BBR has significantly inhibited LFT markers and histological alterations triggered by TAA. In addition, TAA animals demonstrated increased collagen accumulation and upregulated expression of TGF-β1, vimentin, and α-SMA compared to control. The excessive accumulation of collagen, TGF-β1, vimentin, and α-SMA were significantly modulated with BBR treatment. Further, the fluorescence intensity of ROS an activator of NLRP3 including the NLRP3 inflammasome, and its downstream signalling ASC, cleaved IL-1β, and other pro-inflammatory cytokines like TNF-α and IL-6 stimulated by TAA were attenuated by BBR treatment. The current work indicated that BBR significantly ameliorated TAA-induced ALF by inhibiting the extracellular matrix accumulation associated with the NLRP3/IL-1β signalling pathway and could be a viable therapeutic option to treat ALF and other fibroinflammatory diseases.

Current progress on the microbial therapies for acute liver failure

Acute liver failure (ALF), associated with a clinical fatality rate exceeding 80%, is characterized by severe liver damage resulting from various factors in the absence of pre-existing liver disease. The role of microbiota in the progression of diverse liver diseases, including ALF, has been increasingly recognized, with the interactions between the microbiota and the host significantly influencing both disease onset and progression. Despite growing interest in the microbiological aspects of ALF, comprehensive reviews remain limited. This review critically examines the mechanisms and efficacy of microbiota-based treatments for ALF, focusing on their role in prevention, treatment, and prognosis over the past decade.

Deletion of TP signaling in macrophages delays liver repair following APAP-induced liver injury by reducing accumulation of reparative macrophage and production of HGF

BACKGROUND

Acetaminophen (APAP)-induced liver injury is the most common cause of acute liver failure. Macrophages are key players in liver restoration following APAP-induced liver injury. Thromboxane A2 (TXA2) and its receptor, thromboxane prostanoid (TP) receptor, have been shown to be involved in tissue repair. However, whether TP signaling plays a role in liver repair after APAP hepatotoxicity by affecting macrophage function remains unclear.

METHODS

Male TP knockout (TP-/-) and C57BL/6 wild-type (WT) mice were treated with APAP (300 mg/kg). In addition, macrophage-specific TP-knockout (TP△mac) and control WT mice were treated with APAP. We explored changes in liver inflammation, liver repair, and macrophage accumulation in mice treated with APAP.

RESULTS

Compared with WT mice, TP-/- mice showed aggravated liver injury as indicated by increased levels of alanine transaminase (ALT) and necrotic area as well as delayed liver repair as indicated by decreased expression of proliferating cell nuclear antigen (PCNA). Macrophage deletion exacerbated APAP-induced liver injury and impaired liver repair. Transplantation of TP-deficient bone marrow (BM) cells to WT or TP-/- mice aggravated APAP hepatotoxicity with suppressed accumulation of macrophages, while transplantation of WT-BM cells to WT or TP-/- mice attenuated APAP-induced liver injury with accumulation of macrophages in the injured regions. Macrophage-specific TP-/- mice exacerbated liver injury and delayed liver repair, which was associated with increased pro-inflammatory macrophages and decreased reparative macrophages and hepatocyte growth factor (HGF) expression. In vitro, TP signaling facilitated macrophage polarization to a reparative phenotype. Transfer of cultured BM-derived macrophages from control mice to macrophage-specific TP-/- mice attenuated APAP-induced liver injury and promoted liver repair. HGF treatment mitigated APAP-induced inflammation and promoted liver repair after APAP-induced liver injury.

CONCLUSIONS

Deletion of TP signaling in macrophages delays liver repair following APAP-induced liver injury, which is associated with reduced accumulation of reparative macrophages and the hepatotrophic factor HGF. Specific activation of TP signaling in macrophages may be a potential therapeutic target for liver repair and regeneration after APAP hepatotoxicity.

Targeting both ferroptosis and pyroptosis may represent potential therapies for acute liver failure

In this editorial, we comment on the article published in the recent issue of the World Journal of Gastroenterology. Acute liver failure (ALF) is a fatal disease that causes uncontrolled massive hepatocyte death and rapid loss of liver function. Ferroptosis and pyroptosis, cell death forms that can be initiated or blocked concurrently, can play significant roles in developing inflammation and various malignancies. However, their roles in ALF remain unclear. The article discovered the positive feedback between ferroptosis and pyroptosis in the progression of ALF, and revealed that the silent information regulator sirtuin 1 (SIRT1) inhibits both pathways through p53, dramatically reducing inflammation and protecting hepatocytes. This suggests the potential use of SIRT1 and its downstream molecules as therapeutics for ALF. Thus, we will discuss the role of ferroptosis and pyroptosis in ALF and the crosstalk between these cell death mechanisms. Additionally, we address potential treatments that could alleviate ALF by simultaneously inhibiting both cell death pathways, as well as examples of SIRT1 activators being used as disease treatment strategies, providing new insights into the therapy of ALF.

IL-1 receptor-associated kinase family proteins: An overview of their role in liver disease

The interleukin-1 receptor-associated kinase (IRAK) family is a group of serine-threonine kinases that regulates various cellular processes via toll-like receptor (TLR)/interleukin-1 receptor (IL1R)-mediated signaling. The IRAK family comprises four members, including IRAK1, IRAK2, IRAK3, and IRAK4, which play an important role in the expression of various inflammatory genes, thereby contributing to the inflammatory response. IRAKs are key proteins in chronic and acute liver diseases, and recent evidence has implicated IRAK family proteins (IRAK1, IRAK3, and IRAK4) in the progression of liver-related disorders, including alcoholic liver disease, non-alcoholic steatohepatitis, hepatitis virus infection, acute liver failure, liver ischemia-reperfusion injury, and hepatocellular carcinoma. In this article, we provide a comprehensive review of the role of IRAK family proteins and their associated inflammatory signaling pathways in the pathogenesis of liver diseases. The purpose of this study is to explore whether IRAK family proteins can serve as the main target for the treatment of liver related diseases.

Impact of Renal Replacement Therapy on Outcomes of Living Donor Liver Transplantation for Acute Liver Failure: A Cohort Study

Despite the promising role of renal replacement therapy (RRT) in acute liver failure (ALF), high-risk patients need liver transplantation and remain at risk for death due to cerebral complications. The objective of this study was to report outcomes of living donor liver transplantation (LDLT) for ALF with perioperative RRT. This was a single-center retrospective cohort study. Out of 1167 LDLTs, 24 patients had ALF and met the King's College criteria for transplantation. They were categorized into no-RRT (n = 13) and RRT (n = 11) groups. We looked at 1-year posttransplant survival in these patients. The median serum ammonia level at the time of transplant in the no-RRT and RRT groups was 259.5 mcg/dL (222.7-398) and 70.6 mcg/dL (58.1-92.6) (p = 0.005). In the RRT group, serum ammonia level < 100 mcg/dL was achieved in all patients. Seven (53.8%) patients in the no-RRT group and 11/11 (100%) in the RRT group were extubated and regained full consciousness after LDLT (p = 0.013). The 90-day mortality was 6/13 (46.1%) and 2/11 (18.1%) (p = 0.211). There was no brainstem herniation-related mortality in the RRT group, that is, 5/13 (38.4%) and 0/11 (0%) (p = 0.030). The 1-year posttransplant survival was also significantly higher in the RRT group (p = 0.031). The use of RRT lowers serum ammonia levels and might reduce posttransplant mortality due to brainstem herniation.

Acute liver failure: A practical update

Acute liver failure is a rare and dynamic condition, with a broad aetiology and an incompletely understood pathophysiology. Management of this life-threatening disease requires critical care and organ support and frequently early liver transplantation. Proper identification, prevention and treatment of complications such as intracranial hypertension and sepsis are critical to optimising outcomes. The identification of the cause of acute liver failure and the prompt initiation of the aetiological treatment can also improve prognosis. Survival has progressively improved in parallel to advances in medical treatment. Intracranial hypertension complicating hepatic encephalopathy is less frequent than in the past and intracranial pressure monitoring now relies on non-invasive techniques. Current prognostic models have good accuracy to identify patients who will die without liver transplantation but are not able to identify those in whom transplantation is futile. New prognostic markers to select patients for transplantation are still in the pipeline. Therapeutic plasma exchange and, in some centers, early renal replacement therapy are well established treatments for the disease. The use of other artificial liver devices in clinical practice is not supported by evidence. This review is intended to provide a clinical update on the management of acute liver failure, incorporating the most recent advances in the field.

Effect of ferroptosis inhibitors in a murine model of acetaminophen-induced liver injury

Liver injury caused by acetaminophen (APAP) overdose is the leading cause of acute liver failure in western countries. The mode of APAP-induced cell death has been controversially discussed with ferroptosis emerging as a more recent hypothesis. Ferroptosis is characterized by ferrous iron-catalyzed lipid peroxidation (LPO) causing cell death, which can be prevented by the lipophilic antioxidants ferrostatin-1 and UAMC-3203. To assess the efficacy of these ferroptosis inhibitors, we used two murine models of APAP hepatotoxicity, APAP overdose alone or in combination with FeSO4 in fasted male C57BL/6J mice. APAP triggered severe liver injury in the absence of LPO measured as hepatic malondialdehyde (MDA) levels. In contrast, ferrous iron co-treatment aggravated APAP-induced liver injury and caused extensive LPO. Standard doses of ferrostatin-1 did not affect MDA levels or the injury in both models. In contrast, UAMC-3203 partially protected in both models and reduced LPO in the presence of ferrous iron. However, UAMC-3203 attenuated the translocation of phospho-JNK through downregulation of the mitochondrial anchor protein Sab resulting in reduced mitochondrial dysfunction and liver injury. Thus, APAP toxicity does not involve ferroptosis under normal conditions. The lack of effects of ferroptosis inhibitors in the pathophysiology indicates that ferroptosis signaling pathways are not relevant therapeutic targets.

Revitalizing liver function in mice with liver failure through transplantation of 3D-bioprinted liver with expanded primary hepatocytes

The utilization of three-dimensional (3D) bioprinting technology to create a transplantable bioartificial liver emerges as a promising remedy for the scarcity of liver donors. This study outlines our strategy for constructing a 3D-bioprinted liver, using in vitro-expanded primary hepatocytes recognized for their safety and enhanced functional robustness as hepatic cell sources for bioartificial liver construction. In addition, we have developed bioink biomaterials with mechanical and rheological properties, as well as printing capabilities, tailored for 3D bioprinting. Upon heterotopic transplantation into the mesentery of tyrosinemia or 90% hepatectomy mice, our 3D-bioprinted liver effectively restored lost liver functions, consequently extending the life span of mice afflicted with liver injuries. Notably, the inclusion of an artificial blood vessel in our 3D-bioprinted liver allowed for biomolecule exchange with host blood vessels, demonstrating, in principle, the rapid integration of the bioartificial liver into the host vascular system. This model underscores the therapeutic potential of transplantation for the treatment of liver failure diseases.

Whole-exome sequencing for genetic diagnosis of idiopathic liver injury in children

Genome-wide approaches, such as whole-exome sequencing (WES), are widely used to decipher the genetic mechanisms underlying inter-individual variability in disease susceptibility. We aimed to dissect inborn monogenic determinants of idiopathic liver injury in otherwise healthy children. We thus performed WES for 20 patients presented with paediatric-onset recurrent elevated transaminases (rELT) or acute liver failure (ALF) of unknown aetiology. A stringent variant screening was undertaken on a manually-curated panel of 380 genes predisposing to inherited human diseases with hepatobiliary involvement in the OMIM database. We identified rare nonsynonymous variants in nine genes in six patients (five rELT and one ALF). We next performed a case-level evaluation to assess the causal concordance between the gene mutated and clinical symptoms of the affected patient. A genetic diagnosis was confirmed in four rELT patients (40%), among whom two carried novel mutations in ACOX2 or PYGL, and two had previously-reported morbid variants in ABCB4 or PHKA2. We also detected rare variants with uncertain clinical significance in CDAN1, JAG1, PCK2, SLC27A5 or VPS33B in rELT or ALF patients. In conclusion, implementation of WES improves diagnostic yield and enables precision management in paediatric cases of liver injury with unknown aetiology, in particular recurrent hypertransaminasemia.

The chemokine CXCL14 is a novel early prognostic biomarker for poor outcome in acetaminophen-induced acute liver failure

BACKGROUND AND AIMS

Patients with acetaminophen-induced acute liver failure are more likely to die while on the liver transplant waiting list than those with other causes of acute liver failure. Therefore, there is an urgent need for prognostic biomarkers that can predict the need for liver transplantation early after an acetaminophen overdose.

APPROACH AND RESULTS

We evaluated the prognostic potential of plasma chemokine C-X-C motif ligand 14 (CXCL14) concentrations in patients with acetaminophen (APAP) overdose (n=50) and found that CXCL14 is significantly higher in nonsurviving patients compared to survivors with acute liver failure ( p < 0.001). Logistic regression and AUROC analyses revealed that CXCL14 outperformed the MELD score, better discriminating between nonsurvivors and survivors. We validated these data in a separate cohort of samples obtained from the Acute Liver Failure Study Group (n = 80), where MELD and CXCL14 had similar AUC (0.778), but CXCL14 demonstrated higher specificity (81.2 vs. 52.6) and positive predictive value (82.4 vs. 65.4) for death or need for liver transplantation. Next, combining the patient cohorts and using a machine learning training/testing scheme to mimic the clinical scenario, we found that CXCL14 outperformed MELD based on AUC (0.821 vs. 0.787); however, combining MELD and CXCL14 yielded the best AUC (0.860).

CONCLUSIONS

We find in 2 independent cohorts of acetaminophen overdose patients that circulating CXCL14 concentration is a novel early prognostic biomarker for poor outcomes, which may aid in guiding decisions regarding patient management. Moreover, our findings reveal that CXCL14 performs best when measured soon after patient presentation to the clinic, highlighting its importance for early warning of poor prognosis.

A Novel Bifunctional Fusion Protein (Anti-IL-17A-sST2) Protects against Acute Liver Failure, Modulating the TLR4/MyD88 Pathway and NLRP3 Inflammasome Activation

Acute liver failure (ALF) is a serious inflammatory disorder with high mortality rates, which poses a significant threat to human health. The IL-33/ST2 signal is a crucial regulator in inflammation responses associated with lipopolysaccharide (LPS)-induced macrophages. The IL-17A signaling pathway promotes the release of chemokines and inflammatory cytokines, recruiting neutrophils and T cells under LPS stimulation, thus facilitating inflammatory responses. Here, the potential therapeutic benefits of neutralizing the IL-17A signal and modulating the IL-33/ST2 signal in ALF were investigated. A novel dual-functional fusion protein, anti-IL-17A-sST2, was constructed, which displayed high purity and biological activities. The administration of anti-IL-17A-sST2 resulted in significant anti-inflammatory benefits in ALF mice, amelioration of hepatocyte necrosis and interstitial congestion, and reduction in TNF-α and IL-6. Furthermore, anti-IL-17A-sST2 injection downregulated the expression of TLR4 and NLRP3 as well as important molecules such as MyD88, caspase-1, and IL-1β. The results suggest that anti-IL-17A-sST2 reduced the secretion of inflammatory factors, attenuated the inflammatory response, and protected hepatic function by regulating the TLR4/MyD88 pathway and inhibiting the NLRP3 inflammasome, providing a new therapeutic approach for ALF.

Endotoxin tolerance ameliorates lipopolysaccharide/D-galactosamine-induced acute liver failure by negative regulation of the NF-κB/NLRP3 and activation of Nrf2/HO-1 via Sitr1

Acute liver failure (ALF) is a potentially fatal disorder characterized by extensive hepatocyte necrosis and rapid decline in liver function. Numerous factors, including oxidative stress, cell death, and inflammatory responses, are associated with its pathogenesis. Endotoxin tolerance (ET) refers to the phenomenon in which the body or cells exhibit low or no response to high-dose lipopolysaccharide (LPS) stimulation after pre-stimulation with low-dose LPS. However, the specific mechanism through which ET regulates LPS/D-galactosamine (D-GalN)-induced ALF remains unclear. An ALF mouse model was established by intraperitoneal injection of D-GalN (400 mg/kg) and LPS (10 mg/kg). A low dose of LPS (0.1 mg/kg/d) was continuously administered to mice for 5 d before modeling to assess the protective effect of ET. The data from this study showed that ET alleviated the inflammatory response in mice with LPS/D-GalN-induced ALF. ET inhibited LPS-induced oxidative damage and pyroptosis in macrophages in vitro. RNA sequencing analysis showed that the NF-κB/NLRP3 pathway was linked to the anti-inflammatory and antioxidative effects of ET. Furthermore, using western blot, RT-qPCR, and immunofluorescence, we verified that ET inhibited the NF-κB/NLRP3 pathway and triggered the Nrf2/HO-1 signaling pathway to attenuate oxidative stress and cell pyroptosis. Sirt1 knockdown reversed this protective effect. In summary, our research elucidates that ET prevents ALF advancement by upregulating Sirt1 levels, triggering the Nrf2/HO-1 signaling axis, and suppressing the NF-κB/NLRP3 signaling cascade to inhibit oxidative stress and cell pyroptosis. Our results provide a mechanistic explanation for the protective effect of ET against ALF.

The p21+ perinecrotic hepatocytes produce the chemokine CXCL14 after a severe acetaminophen overdose promoting hepatocyte injury and delaying regeneration

Fifty percent of all acute liver failure (ALF) cases in the United States are due to acetaminophen (APAP) overdose. Assessment of canonical features of liver injury, such as plasma alanine aminotransferase activities are poor predictors of acute liver failure (ALF), suggesting the involvement of additional mechanisms independent of hepatocyte death. Previous work demonstrated a severe overdose of APAP results in impaired regeneration, the induction of senescence by p21, and increased mortality. We hypothesized that a discrete population of p21+ hepatocytes acquired a secretory phenotype that directly impedes liver recovery after a severe APAP overdose. Leveraging in-house human APAP explant liver and publicly available single-nuclei RNAseq data, we identified a subpopulation of p21+ hepatocytes enriched in a unique secretome of factors, such as CXCL14. Spatial transcriptomics in the mouse model of APAP overdose confirmed the presence of a p21+ hepatocyte population that directly surrounded the necrotic areas. In both male and female mice, we found a dose-dependent induction of p21 and persistent circulating levels of the p21-specific constituent, CXCL14, in the plasma after a severe APAP overdose. In parallel experiments, we targeted either the putative senescent hepatocytes with the senolytic drugs, dasatinib and quercetin, or CXCL14 with a neutralizing antibody. We found that targeting CXCL14 greatly enhanced liver recovery after APAP-induced liver injury, while targeting senescent hepatocytes had no effect. These data support the conclusion that the sustained induction of p21 in hepatocytes with persistent CXCL14 secretion are critical mechanistic events leading to ALF in mice and human patients.

Determinants, profile and outcomes of hepatitis A virus-associated severe acute liver injury in adults

BACKGROUND AND OBJECTIVES

Hepatitis A virus (HAV)-related hepatitis is witnessing an epidemiological transition with increasing trends in adults. While uncomplicated hepatitis remains common, evidence suggests it to be a growing cause for acute liver failure (ALF). In between the two extremes exists severe acute liver injury (s-ALI) which has a propensity to transition to ALF. We aimed at describing the clinical profile of patients with HAV-related s-ALI and identifying potential predictors of progression to ALF.

METHODS

This was a single-center retrospective analysis of adult patients admitted with HAV-related s-ALI between April 2022 and December 2023. Demographic and laboratory parameters were compared between patients with only s-ALI and those with ALF. Predictors of progression from s-ALI to ALF were identified using logistic regression.

RESULTS

Forty-three patients satisfied criteria of s-ALI, of which 33 (76.7%) had only s-ALI, while 10 (23.3%) had ALF. Patients with s-ALI had lesser leukocytosis (6.3 ± 3 vs. 13.2 ± 4.8), less incidence of acute kidney injury (9.1% vs. 40%) and lower model for end-stage liver disease (MELD) (20 [18-24.5] vs. 31.5 [26-42]), arterial lactate (2.1 [1.3-3.1] vs. 6.3 [5.2-8.0]), arterial ammonia (94 [72-118] vs. 299 [188-573]), procalcitonin (0.5 [0.28-1.25] vs. 3.2 [1.2-6.1]) and ferritin (482 [213-1633] vs. 5186 [1341-11,053]) compared to HAV-ALF (p < 0.05 for all). Three patients (9.09%) with s-ALI progressed to ALF of whom one (3%) died. Baseline ammonia levels (unadjusted odds ratio [OR] 1.03 [1.01-1.06]) and leukocyte count (OR 1.00 [1.00-1.01]) tended to be associated with ALF progression, although none was significant after multi-variable adjustment. Ammonia levels had an area under receiver operating curve of 0.816 (0.64-0.93) (p = 0.009) (cut-off of 144 μmol/L). Additional comorbidities did not impact overall outcomes.

CONCLUSION

HAV presents as s-ALI in young adults, with almost one in 10 progressing to ALF. Baseline ammonia may be an important predictor of progression even in s-ALI, but mandates larger well-designed studies.

Extra-corporeal non-liver transplant therapies for acute liver failure: Focus on plasma exchange and continuous renal replacement therapy

The acute inflammatory milieu in patients with acute liver failure (ALF) results in 'toxic' blood in these patients. In vitro experiments have shown that the plasma obtained from ALF patients is toxic to rabbit hepatocytes and inhibits regeneration of rat hepatocytes. Treatments such as plasma exchange and continuous renal replacement therapy to cleanse the blood have improved survival in ALF patients. In the liver microcirculation, the exchange of fluid across fenestrae in liver sinusoidal endothelial cells (LSECs) is vital for proper functioning of hepatocytes. Clogging of the liver filter bed by inflammatory debris and cells ('traffic jam hypothesis') impeding blood flow in sinusoids may in turn reduce the exchange of fluid across LSEC fenestrae and cause dysfunction and necrosis of hepatocytes in ALF patients. In mouse model of paracetamol overdose, disturbances in microcirculation in the liver preceded the development of injury and necrosis of hepatocytes. This may represent a reversible pathophysiological mechanism in ALF which may be improved by the anti-inflammatory effect of plasma exchange. Wider access to urgent plasma exchange is a major advantage compared to urgent liver transplantation to treat ALF patients worldwide, especially so in resource constrained settings. Continuous hemo-filtration or dialysis is used to reduce ammonia levels and treat cerebral edema in ALF patients. In this review, we discuss the different modalities to cleanse the blood in ALF patients, with an emphasis on plasma exchange, from a hepatology perspective.

Biomarker discovery in acetaminophen hepatotoxicity: leveraging single-cell transcriptomics and mechanistic insight

INTRODUCTION

Acetaminophen (APAP) overdose is the leading cause of drug-induced liver injury and can cause a rapid progression to acute liver failure (ALF). Therefore, the identification of prognostic biomarkers to determine which patients will require a liver transplant is critical for APAP-induced ALF.

AREAS COVERED

We begin by relating the mechanistic investigations in mouse models of APAP hepatotoxicity to the human APAP overdose pathophysiology. We draw insights from the established sequence of molecular events in mice to understand the progression of events in the APAP overdose patient. Through this mechanistic understanding, several new biomarkers, such as CXCL14, have recently been evaluated. We also explore how single-cell RNA sequencing, spatial transcriptomics, and other omics approaches have been leveraged for identifying novel biomarkers and how these approaches will continue to push the field of biomarker discovery forward.

EXPERT OPINION

Recent investigations have elucidated several new biomarkers or combination of markers such as CXCL14, a regenerative miRNA signature, a cell death miRNA signature, hepcidin, LDH, CPS1, and FABP1. While these biomarkers are promising, they all require further validation. Larger cohort studies analyzing these new biomarkers in the same patient samples, while adding these candidate biomarkers to prognostic models will further support their clinical utility.

The Evolution of Circulating Biomarkers for Use in Acetaminophen/Paracetamol-Induced Liver Injury in Humans: A Scoping Review

Acetaminophen (APAP) is a widely used drug, but overdose can cause severe acute liver injury. The first reports of APAP hepatotoxicity in humans were published in 1966, shortly after the development of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) as the first biomarkers of liver injury as opposed to liver function. Thus, the field of liver injury biomarkers has evolved alongside the growth in APAP hepatotoxicity incidence. Numerous biomarkers have been proposed for use in the management of APAP overdose patients in the intervening years. Here, we comprehensively review the development of these markers from the 1960s to the present day and briefly discuss possible future directions.