Cholestatic Injury Research Articles

Idiosyncratic Hepatocellular Drug-Induced Liver Injury by Flucloxacillin with Evidence Based on Roussel Uclaf Causality Assessment Method and HLA B*57:01 Genotype: From Metabolic CYP 3A4/3A7 to Immune Mechanisms.

Idiosyncratic drug-induced liver injury (iDILI) by flucloxacillin presents as both cholestatic and hepatocellular injury. Its mechanistic steps are explored in the present analysis as limited data exist on the cascade of events leading to iDILI in patients with an established diagnosis assessed for causality by the Roussel Uclaf Causality Assessment Method (RUCAM). Studies with human liver microsomes showed that flucloxacillin is a substrate of cytochrome P450 (CYP) with ist preferred isoforms CYP 3A4/3A7 that toxified flucloxacillin toward 5'-hydroxymethylflucloxacillin, which was cytotoxic to human biliary epithelial cell cultures, simulating human cholestatic injury. This provided evidence for a restricted role of the metabolic CYP-dependent hypothesis. In contrast, 5'-hydroxymethylflucloxacillin generated metabolically via CYP 3A4/3A7 was not cytotoxic to human hepatocytes due to missing genetic host features and a lack of non-parenchymal cells, including immune cells, which commonly surround the hepatocytes in the intact liver in abundance. This indicated a mechanistic gap regarding the clinical hepatocellular iDILI, now closed by additional studies and clinical evidence based on HLA B*57:01-positive patients with iDILI by flucloxacillin and a verified diagnosis by the RUCAM. Naïve T-cells from volunteers expressing HLA B*57:01 activated by flucloxacillin when the drug antigen was presented by dendritic cells provided the immunological basis for hepatocellular iDILI caused by flucloxacillin. HLA B*57:01-restricted activation of drug-specific T-cells caused covalent binding of flucloxacillin to albumin acting as a hapten. Following drug stimulation, T-cell clones expressing CCR4 and CCR9 migrated toward CCL17 and CCL25 and secreted interferon-γ and cytokines. In conclusion, cholestatic injury can be explained metabolically, while hepatocellular injury requires both metabolic and immune activation.

Histologic Features of Liver Injury Associated With SARS-CoV-2 Messenger RNA Vaccines.

Many drugs can induce liver injury; however, vaccine-induced liver injury is a rare phenomenon. SARS-CoV-2 messenger RNA (mRNA) vaccines are now widely administered, and clinical evidence of liver injury has been reported. To characterize the histologic features of SARS-CoV-2 mRNA vaccine-associated liver injury. Thirteen liver biopsies from 12 patients with elevated liver enzymes clinically favored to be secondary to SARS-CoV-2 mRNA vaccine were identified between 2021 and 2022. Demographics, clinical information, and histologic features of liver biopsies were reviewed. All patients (median age, 58 years; M:F = 4:8) received at least 1 dose of SARS-CoV-2 mRNA vaccines (7 Pfizer and 5 Moderna). Four patients had a history of liver disease. Nine patients developed symptoms between 1 day and 2 months after receiving the vaccine dose. Viral serologies were negative. Drug-induced liver injury was thought to be less likely clinically in the 3 patients who had started new medications. Autoimmune antibodies were detected in 9 patients. Moderate to severe active hepatitis was the dominant histologic pattern of injury (9 of 13 biopsies; 69%). Resolving hepatitis, cholestatic hepatitic injury, and bile duct injury were identified in 1 biopsy each. All patients recovered spontaneously or with steroid therapy except one patient who developed autoimmune hepatitis. Moderate to severe active hepatitis is commonly observed in SARS-CoV-2 mRNA vaccine-associated liver injury, and female patients may be more susceptible to injury. Liver injury resolves spontaneously or with steroid treatment. In rare cases, these vaccines may trigger an underlying immune condition.

Beneficial effects of hepatic cyclooxygenase-2 expression against cholestatic injury after common bile duct ligation in mice.

Cyclooxygenase-2 (COX-2) is involved in different liver diseases, but little is known about the significance of COX-2 in cholestatic injury. This study was designed to elucidate the role of COX-2 expression in hepatocytes during the pathogenesis of obstructive cholestasis. We used genetically modified mice constitutively expressing human COX-2 in hepatocytes. Transgenic mice (hCOX-2-Tg) and their wild-type (Wt) littermates were either subjected to a mid-abdominal laparotomy or common bile duct ligation (BDL) for 2 or 5 days. Then, we explored the mechanisms underlying the role of COX-2 and its derived prostaglandins in liver function, and the synthesis and excretion of bile acids (BA) in response to cholestatic liver injury. After BDL, hCOX-2-Tg mice showed lower grades of hepatic necrosis and inflammation than Wt mice, in part by a reduced hepatic neutrophil recruitment associated with lower mRNA levels of pro-inflammatory cytokines. Furthermore, hCOX-2-Tg mice displayed a differential metabolic pattern of BA synthesis that led to an improved clearance after BDL-induced accumulation. In addition, an enhanced response to the BDL-induced oxidative stress and hepatic apoptosis was observed. Invitro experiments using hepatic cells that stably express hCOX-2 confirmed the cytoprotective role of prostaglandin E2 against BA toxicity. Taken together, our data indicate that constitutive expression of COX-2 in hepatocytes ameliorates cholestatic liver injury in mice by reducing inflammation and cell damage and by modulating BA metabolism, pointing to a role for COX-2 as a defensive response against cholestasis-derived BA accumulation and injury.

Generation of human iPSC-derived 3D bile duct within liver organoid by incorporating human iPSC-derived blood vessel

In fetal development, tissue interaction such as the interplay between blood vessel (BV) and epithelial tissue is crucial for organogenesis. Here we recapitulate the spatial arrangement between liver epithelial tissue and the portal vein to observe the formation of intrahepatic bile ducts (BDs) from human induced pluripotent stem cells (hiPSC). We co-culture hiPSC-liver progenitors on the artificial BV consisting of immature smooth muscle cells and endothelial cells, both derived from hiPSCs. After 3 weeks, liver progenitors within hiPSC-BV-incorporated liver organoids (BVLO) differentiate to cholangiocytes and acquire epithelial characteristics, including intercellular junctions, microvilli on the apical membrane, and secretory functions. Furthermore, liver surface transplanted-BVLO temporarily attenuates cholestatic injury symptoms. Single cell RNA sequence analysis suggests that BD interact with the BV in BVLO through TGFβ and Notch pathways. Knocking out JAG1 in hiPSC-BV significantly attenuates bile duct formation, highlighting BVLO potential as a model for Alagille syndrome, a congenital biliary disease. Overall, we develop a novel 3D co-culture method that successfully establishes functional human BDs by emulating liver epithelial-BV interaction.

Drug-induced cholestatic liver diseases.

Cholestatic DILI is an important and frequently challenging differential diagnosis in patients presenting with elevated liver tests with predominant elevation in alkaline phosphatase. A number of competing etiologies need to be ruled out, such as hepatobiliary malignancy, choledocholithiasis, cholestatic forms of viral hepatitis, cholestasis of sepsis, primary and secondary cholangitis, and right-sided cardiac failure to name a few. Important advances have occurred in the understanding and knowledge of the clinical phenotypes, new etiological agents, risk factors, pathophysiology, and genetic determinants of drug-induced cholestasis since the last review on drug-induced cholestasis was published in Hepatology in 2011. Secondary sclerosing cholangitis (SSC) due to drugs has been well documented for several different drugs. Checkpoint inhibitors are one of the types of drugs shown to lead to secondary sclerosing cholangitis. Several new herbal and dietary supplements have recently been shown to lead to cholestatic liver injury. A number of genetic risk factors for cholestasis due to drugs have been identified in the last decade, and the pathogenesis behind cholestatic injury is better defined. In this review, the focus is on diagnostic approach and description of new clinical phenotypes such as secondary sclerosing cholangitis and vanishing bile duct syndrome. Furthermore, the review provides an overview of the risk factors, genetic determinants, and the pathophysiology of hepatobiliary transporters leading to cholestasis. Management, areas of uncertainty, and future direction are also presented.

Drug-induced Liver Injury Caused by Levetiracetam

Levetiracetam, known as Keppra, is an antiepileptic drug that is commonly used due to its rare side effects, particularly on the liver. It is mainly excreted by the kidneys with minimal hepatic metabolism. Drug-induced liver injury associated with Levetiracetam is extremely rare. Few cases of Levetiracetam-induced liver toxicity and failure were declared. Until now, there are no previously reported cases of mixed pattern liver injury related to this drug. We report a case of a patient taking Levetiracetam, that was found to have mixed pattern liver injury. Our patient experienced important rapid improvement of hepatocellular injury and a delayed improvement of cholestatic pattern after Levetiracetam discontinuation, suggesting the mentioned association. This case report is the first to establish both hepatocellular and cholestatic injury associated with Levetiracetam. We would like to highlight this side effect, though rare, of this frequently used drug in medical practice.

Liver injury associated with endothelin receptor antagonists: a pharmacovigilance study based on FDA adverse event reporting system data.

Endothelin receptor antagonists are commonly used in clinical practice, with concerns about their hepatotoxicity. This study aimed to conduct a comprehensive pharmacovigilance study based on FDA adverse event reporting system data to evaluate the possible association between endothelin receptor antagonists and drug-induced liver injury. Adverse event reports from FDA adverse event reporting system between January 2004 and December 2022 were analyzed. Disproportionality algorithms, including reporting odds ratio and information component, were used to evaluate the association between endothelin receptor antagonists and liver injury. Sex- and age-stratified analyses of drug-induced liver injury events were also conducted in relation to endothelin receptor antagonists. Significant associations between bosentan, macitentan, and liver injury were identified. Bosentan showed a strong link with liver injury, with reporting odds ratios for cholestatic injury at 7.59 (95% confidence interval: 6.90-8.35), hepatocellular injury at 5.63 (5.29-6.00), and serious drug-related hepatic disorders events at 1.33 (1.24-1.43). Drug-induced liver injury signals associated with bosentan were detected in all age groups. Macitentan was associated with liver injury, with reporting odds ratios for hepatic failure at 1.64 (1.39-1.94), cholestatic injury at 1.62 (1.43-1.83), and serious drug-related hepatic disorders events at 1.40 (1.29-1.51). No drug-induced liver injury signal was detected for ambrisentan, and no significant sex differences were observed in drug-induced liver injury events. Both bosentan and macitentan are associated with liver injury. Routine monitoring of serum aminotransferase levels is recommended, especially in patients at higher risk of liver injury. Further research into drug-drug interactions involving endothelin receptor antagonists is warranted.

Novel Liver Injury Phenotypes and Outcomes in Clinical Trial Participants with Pulmonary Hypertension.

Rationale: Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) cause right ventricular dysfunction, which can impact other solid organs. However, the profiles and consequences of hepatic injury resulting from PAH and CTEPH have not been well studied. Objectives: We aimed to identify underlying patterns of liver injury in a cohort of patients with PAH and CTEPH enrolled in 15 randomized clinical trials conducted between 1998 and 2014. Methods: We used unsupervised machine learning to identify liver injury clusters in 13 trials and validated the findings in two additional trials. We then determined whether these liver injury clusters were associated with clinical outcomes or treatment effect heterogeneity. Measurements and Main Results: Our training dataset included 4,219 patients and our validation dataset included 1,756 patients with serum total bilirubin, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, and albumin data. Using k-means clustering, we identified phenotypes with no liver injury, hepatocellular injury, cholestatic injury, and combined injury patterns. Patients in the cholestatic injury liver cluster had the shortest time to clinical worsening and the highest risk of mortality. The cholestatic injury group also experienced the greatest placebo-corrected treatment effect on 6-minute-walk distance. Randomization to the experimental arm transitioned patients to a healthier liver status. Conclusions: Liver injury was associated with adverse outcomes in patients with PAH and CTEPH. Randomization to active treatment had beneficial effects on liver health compared with placebo. The role of liver disease (often subclinical) in determining outcomes warrants prospective studies.

Clinical Features and Risk Factors for Drug-Induced Liver Injury: A Retrospective Study From China

PurposeWith the prolongation of human life expectancy and the outbreak of COVID-19, antineoplastic agents, anti-infective drugs, and cardiovascular system drugs have been widely applied, resulting in a growing incidence of drug-induced liver injury (DILI) year by year. This study aimed to investigate signals, clinical characteristics, and risk factors in patients with liver injury. MethodsA retrospective analysis was conducted on inpatients clinically diagnosed with DILI from 2019 to 2021 in one tertiary hospital in mainland China. The hepatic biochemical indices, clinical manifestations and suspected drugs of the patients were counted. We determined causality assessed by the Roussel Uclaf Causality Assessment Method in patients that the biochemistry met the diagnostic criteria recommended by the International Serious Adverse Events Consortium and compared them with contemporaneous patients diagnosed as DILI but with hepatic biochemical abnormalities only to identify the injure types and risk factors for DILI. FindingsA total of 1167 patients from 2639 initial participants with DILI were included. According to the injured target cells, it can be divided into hepatocellular injury type 351 cases (30.08%), cholestatic injury type 97 cases (8.31%), mixed injury type 27 cases (2.31%), and biochemical abnormal only type 692 cases (59.30%). It involved 1738 cases of suspected drugs, 349 drugs, and the top 3 drug categories were antineoplastic agents, anti-infectives, and traditional Chinese medicines, with Cyclophosphamide, Atorvastatin, and Liuzasulfapyridine as the top 3 in order of ranking. The main symptoms of patients were darker urine, decreased appetite, and yellow sclera. The overall prognosis of patients with DILI was favorable, with 280 recovered cases (23.99%), 691 improved cases (59.21%), 189 not improved cases (16.20%), and 7 deaths (0.60%). There were significant differences in gender, age, malignancy, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bilirubin, gamma-glutamyltransferase, albumin, international normalized ratio, and prognosis among patients with different injury types (P < 0.05). Multiple logistic regression analysis showed that female (odds ratio [OR] = 1.897, P < 0.001), alcohol use (OR = 1.905, P = 0.001), malignancy (OR = 0.417, P < 0.001), and pregnancy (OR = 0.201, P = 0.011) were independent factors influencing DILI. ImplicationsFor most patients with liver injury, the manifestations are mild elevation of liver biochemistry without other symptoms (biochemical abnormal only type). The rest of the patients are predominantly of the hepatocellular injury type. Female and alcohol abuse patients are the risk factors of DILI, reminding clinicians to strengthen education on safe drug use, give individualized treatment, and regularly monitor liver function indexes in the patients.

Clinical and biochemical characteristics, and outcome in 33 patients with ceftriaxone-induced liver injury.

To summarize the clinical and biochemical characteristics of patients with ceftriaxone-induced liver injury and guide the selection of safe medication. Retrieved domestic and foreign databases from inception to October 2023, collected case data conforming to ceftriaxone-induced liver injury, and statistically analyzed the data. A total of 617 articles were retrieved, and 16 articles with 33 cases (10 children, 23 adults) were included. Males represented 60% (18/30), with a male-to-female ratio of 1.5:1. The age of onset ranged from 2 days to 96 years, with 15 of 23 adults (65%) over 55 years old. The time from ceftriaxone use to liver injury fluctuated between 0.5 and 47 days. Only 9 patients (27.3%, 9/33) had clinical symptoms, and the clinical classification was dominated by cholestatic injury (46.2%, 12/26). There was a significant difference in the clinical classification of ceftriaxone-induced liver injury between children and adults (P = 0.0126), with hepatocellular injury predominating in children and cholestatic injury predominating in adults. The severity of liver injury was mainly mild (66.7%, 12/18). Peak values of alanine aminotransferase ranging from 228.5 to 8098 U/L, aspartate aminotransferase ranging from 86.7 to 21575 U/L, alkaline phosphatase ranging from 143 to 2434 U/L, and total bilirubin ranging from 3.35 to 66.1mg/dL. There was a significant difference in peak values of alkaline phosphatase between children and adults (P = 0.027), with a higher peak value of alkaline phosphatase in adults (1039 ± 716.4 U/L vs. 257 ± 134.9 U/L). Patients with normal imaging examinations accounted for the majority (61.5%, 7/13). The prognosis of 32 patients (97%, 32/33) was good, and one child with sickle cell anemia who developed immune hemolysis, progressive renal failure, and acute liver injury after using ceftriaxone died in the end. Ceftriaxone-induced liver injury can occur at any age, with a higher risk in the elderly, and age may be related to the clinical classification. Although the clinical manifestations are not specific, close monitoring of liver biochemical indicators during the use can detect liver injury early. Most cases have a good prognosis, but for people with concomitant sickle cell anemia, it is necessary to be vigilant about the occurrence of severe hemolytic anemia.

A spatiotemporal atlas of cholestatic injury and repair in mice.

Cholestatic liver injuries, characterized by regional damage around the bile ductular region, lack curative therapies and cause considerable mortality. Here we generated a high-definition spatiotemporal atlas of gene expression during cholestatic injury and repair in mice by integrating spatial enhanced resolution omics sequencing and single-cell transcriptomics. Spatiotemporal analyses revealed a key role of cholangiocyte-driven signaling correlating with the periportal damage-repair response. Cholangiocytes express genes related to recruitment and differentiation of lipid-associated macrophages, which generate feedback signals enhancing ductular reaction. Moreover, cholangiocytes express high TGFβ in association with the conversion of liver progenitor-like cells into cholangiocytes during injury and the dampened proliferation of periportal hepatocytes during recovery. Notably, Atoh8 restricts hepatocyte proliferation during 3,5-diethoxycarbonyl-1,4-dihydro-collidin damage and is quickly downregulated after injury withdrawal, allowing hepatocytes to respond to growth signals. Our findings lay a keystone for in-depth studies of cellular dynamics and molecular mechanisms of cholestatic injuries, which may further develop into therapies for cholangiopathies.

Sortilin in Biliary Epithelial Cells Promotes Ductular Reaction and Fibrosis during Cholestatic Injury

Cholestatic injuries are accompanied by a ductular reaction, initiated by proliferation and activation of biliary epithelial cells (BEC), leading to fibrosis. Sortilin (Sort1) facilitates IL-6 secretion and leukemia inhibitory factor (LIF) signaling. This study investigated the interplay between sortilin, IL-6 and LIF in cholestatic injury-induced ductular reaction, morphogenesis of new ducts and fibrosis. Cholestatic injury was induced by bile duct ligation (BDL) in WT and Sort1-/- mice, with or without augmentation of IL-6 or LIF. Mice with BEC sortilin deletion (HgfapcreSort1fl/fl) and controls were subjected to BDL and 3,5-Diethoxycarbonyl-1,4-Dihydrocollidine diet (DDC)-induced cholestatic injury. Sort1-/- mice displayed reduced BEC proliferation and expression of BEC reactive markers. Administration of LIF or IL-6 restored BEC proliferation in Sort1-/- mice, without affecting BEC reactive or inflammatory markers. Sort1-/- mice also displayed impaired morphogenesis, which was corrected by LIF treatment. Similarly, HgfapcreSort1fl/f mice exhibited reduced BEC proliferation, but similar expression of reactive and inflammatory markers. Serum IL-6 and LIF levels were comparable, yet liver pSTAT3 was reduced, indicating that sortilin is essential for co-activation of LIFR/gp130 signaling in BEC, but not for IL-6 secretion. Notably, HgfapcreSortfl/fl mice displayed impaired morphogenesis and diminished fibrosis following BDL and DDC. In conclusion, sortilin-governed engagement of LIF signaling in BEC promotes ductular reaction and morphogenesis during cholestatic injury. Moreover, BEC sortilin is pivotal for the development of fibrosis.

Graves Disease - A Comprehensive Review

Graves Disease (GD) is an inflammatory disorder that often results in hyperthyroidism. GD is particularly prone to affecting women, African Americans, individuals with pre-existing autoimmune conditions, and first-degree relatives of those with GD. GD presents through a breakdown of immune tolerance against thyroid antigens. This occurs through a multifactorial autoimmune dysfunction of environmental and mainly genetic contribution. Hereditary predisposition accounts for 79% of the GD risk and increases susceptibility to dysfunction by environmental risk factors such as smoking, vitamin D deficiency, and stressful life events. GD is caused by a disruption of the thyroid gland on a molecular level. The disease is characterized by an overstimulation of the thyroid gland causing hyperthyroidism. This issue is caused by thyroid-stimulating immunoglobulin (TSI) synthesized by B cells. These immunoglobulins bind to the TSH receptors on the thyroid gland, activating it and producing an abundance of the thyroid hormones, levothyroxine (T4) and triiodothyronine (T3). The clinical presentation of GD encompasses a diverse array of signs and symptoms, from common manifestations such as palpitations, weight reduction, and exophthalmos, to less conventional presentations like cardiac complications and cholestatic hepatic injury. There are many methods of diagnosis that are used for GD including the gold standard, which tests for TSI and antibodies against the TSH receptor. Other methods include radioactive iodine uptake and CT scans that test for thyroid enlargement and are used to substitute radioactive iodine uptake tests for pregnant women. The three classical treatments for GD are antithyroid drugs, radioiodine treatment, and thyroidectomy. Additional treatments include corticosteroids which are used to decrease exophthalmos. Beta-adrenergic blockers are used for tachycardia, palpitations, and also blocking the peripheral conversion of T4 to T3. Immunotherapies, such as Mycophenolate mofetil and Azathioprine show promise as potential treatments are currently being investigated. This comprehensive review provides an up-to-date compact analysis of literature pertinent to the epidemiology, etiology, risk factors, genetics, pathophysiology, classifications, clinical presentation, diagnosis, and treatments of GD.

Soluble Semaphorin 4D Serum Concentrations Are Elevated in Critically Ill Patients with Liver Cirrhosis and Correlate with Aminotransferases.

Semaphorin 4D (Sema4D), also known as CD100, is a multifunctional transmembrane protein with immunoregulatory functions. Upon the activation of immune cells, soluble Semaphorin 4D (sSema4D) is proteolytically cleaved from the membrane by metalloproteinases. sSema4D levels are elevated in various (auto-)inflammatory diseases. Our aim was to investigate sSema4D levels in association with sepsis and critical illnesses and to evaluate sSema4D's potential as a prognostic biomarker. We measured sSema4D levels in 192 patients upon admission to our medical intensive care unit. We found similar levels of sSema4D in 125 patients with sepsis compared to 67 non-septic patients. sSema4D levels correlated with leukocytes but not with other markers of systemic inflammation such as C-reactive protein or procalcitonin. Most interestingly, in a subgroup of patients suffering from pre-existing liver cirrhosis, we observed significantly higher levels of sSema4D. Consistently, sSema4D was also positively correlated with markers of hepatic and cholestatic injury. Our study suggests that sSema4D is not regulated in sepsis compared to other causes of critical illness. However, sSema4D seems to be associated with hepatic injury and inflammation.

Utility of Liver Biopsy in the Diagnosis and Management of Possible Drug-Induced Liver Injury in Patients Receiving Antituberculosis Therapy: A Retrospective Study.

Drug-induced liver injury (DILI) secondary to ATT treatment (TB-DILI) is reported in 2-28% of patients. We present here a series of clinical cases of suspected DILI arising during antituberculosis treatment, studied with the aid of liver biopsy. this was a retrospective descriptive study including 10 tuberculosis patients who underwent liver biopsy for suspected TB-DILI at the "Lazzaro Spallanzani" Institute from 2017 to 2022. Ten patients who underwent LB were extracted from the database and included in the retrospective study cohort. According to the clinical classification, eight patients had hepatocellular liver injury, one patient had cholestatic injury, and another had mixed-type injury. Histopathological diagnosis revealed liver damage due to DILI in 5/10 (50%) cases. In one case, liver biopsy showed necrotizing granulomatous hepatitis. Severe and persistent elevation of hepatic transaminases, hepatic cholestasis despite discontinuation of therapy, and other suspected hepatic conditions are indications for liver biopsy, which remains a valuable tool in the evaluation of selected tuberculosis patients with suspected DILI for many reasons. However, the decision to perform a liver biopsy should be based on clinical judgment, considering the benefits and risks of the procedure.

PGC1α deficiency reverses cholestasis-induced liver injury via attenuating hepatic inflammation and promoting bile duct remodeling

ObjectivesCholestatic liver diseases are characterized by hepatocellular damage, cholangiocyte proliferation, and progressive fibrosis. Bile duct ligation (BDL) is widely used to resemble liver injuries induced by cholestasis. Peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC1α) was reported to play a critical role in multiple biological responses. Nevertheless, whether PGC1α is involved in bile acid metabolism and biliary disorders remains unclear. This study aimed to investigate the effect of PGC1α on hepatic responses after cholestatic injury. Materials and methodsWild-type mice were subjected to BDL or sham surgery for 14 days and human liver specimens from patients with primary biliary cholangitis (PBC) were collected to detect the expression of PGC1α. Hepatic-specific PGC1α knockout mice (HKO) were constructed and subjected to BDL, in which the effects of PGC1α on cholestatic liver injury were demonstrated by biochemical and histopathological assessments, immunoblotting, and metabolomics. ResultsThe expression of PGC1α was upregulated in the liver of PBC patients and murine models. Both in vivo and in vitro experiments supported the protective effects of PGC1α on cholestasis-induced hepatocyte injury. Infiltrated inflammatory cells after BDL were decreased in HKO mice. Inhibited Wnt/β-Catenin pathway and enhanced Notch signaling promoted transdifferentiation of hepatic progenitor cells (HPC)/ hepatocytes into cholangiocytes, leading to the greater ductular reaction observed in the HKO mice. But bile acids metabolism and mitochondrial function were not affected due to hepatic PGC1α deficiency in cholestasis. ConclusionsHepatic-specific deletion of PGC1α regulated liver regeneration by promoting ductular reactions, thereby exerting protective effects against BDL-induced liver injury, which could be a new potential therapeutic target.

S3816 An Unusual Case of Immune Checkpoint Inhibitor-Mediated Cholestatic Injury

S3816 An Unusual Case of Immune Checkpoint Inhibitor-Mediated Cholestatic Injury

Loss of TAZ after YAP deletion severely impairs foregut development and worsens cholestatic hepatocellular injury.

We previously showed that loss of yes-associated protein 1 (YAP) in early liver development (YAPKO) leads to an Alagille syndrome-like phenotype, with failure of intrahepatic bile duct development, severe cholestasis, and chronic hepatocyte adaptations to reduce liver injury. TAZ, a paralog of YAP, was significantly upregulated in YAPKO hepatocytes and interacted with TEA domain family member (TEAD) transcription factors, suggesting possible compensatory activity. We deleted both Yap1 and Wwtr1 (which encodes TAZ) during early liver development using the Foxa3 promoter to drive Cre expression, similar to YAPKO mice, resulting in YAP/TAZ double knockout (DKO) and YAPKO with TAZ heterozygosity (YAPKO TAZHET). We evaluated these mice using immunohistochemistry, serum biochemistry, bile acid profiling, and RNA sequencing. DKO mice were embryonic lethal, but their livers were similar to YAPKO, suggesting an extrahepatic cause of death. Male YAPKO TAZHET mice were also embryonic lethal, with insufficient samples to determine the cause. However, YAPKO TAZHET females survived and were phenotypically similar to YAPKO mice, with increased bile acid hydrophilicity and similar global gene expression adaptations but worsened the hepatocellular injury. TAZ heterozygosity in YAPKO impacted the expression of canonical YAP targets Ctgf and Cyr61, and we found changes in pathways regulating cell division and inflammatory signaling correlating with an increase in hepatocyte cell death, cell cycling, and macrophage recruitment. YAP loss (with or without TAZ loss) aborts biliary development. YAP and TAZ play a codependent critical role in foregut endoderm development outside the liver, but they are not essential for hepatocyte development. TAZ heterozygosity in YAPKO livers increased cell cycling and inflammatory signaling in the setting of chronic injury, highlighting genes that are especially sensitive to TAZ regulation.

Optimization of an adverse outcome pathway network on chemical-induced cholestasis using an artificial intelligence-assisted data collection and confidence level quantification approach

BackgroundAdverse outcome pathway (AOP) networks are versatile tools in toxicology and risk assessment that capture and visualize mechanisms driving toxicity originating from various data sources. They share a common structure consisting of a set of molecular initiating events and key events, connected by key event relationships, leading to the actual adverse outcome. AOP networks are to be considered living documents that should be frequently updated by feeding in new data. Such iterative optimization exercises are typically done manually, which not only is a time-consuming effort, but also bears the risk of overlooking critical data. The present study introduces a novel approach for AOP network optimization of a previously published AOP network on chemical-induced cholestasis using artificial intelligence to facilitate automated data collection followed by subsequent quantitative confidence assessment of molecular initiating events, key events, and key event relationships. MethodsArtificial intelligence-assisted data collection was performed by means of the free web platform Sysrev. Confidence levels of the tailored Bradford-Hill criteria were quantified for the purpose of weight-of-evidence assessment of the optimized AOP network. Scores were calculated for biological plausibility, empirical evidence, and essentiality, and were integrated into a total key event relationship confidence value. The optimized AOP network was visualized using Cytoscape with the node size representing the incidence of the key event and the edge size indicating the total confidence in the key event relationship. ResultsThis resulted in the identification of 38 and 135 unique key events and key event relationships, respectively. Transporter changes was the key event with the highest incidence, and formed the most confident key event relationship with the adverse outcome, cholestasis. Other important key events present in the AOP network include: nuclear receptor changes, intracellular bile acid accumulation, bile acid synthesis changes, oxidative stress, inflammation and apoptosis. ConclusionsThis process led to the creation of an extensively informative AOP network focused on chemical-induced cholestasis. This optimized AOP network may serve as a mechanistic compass for the development of a battery of in vitro assays to reliably predict chemical-induced cholestatic injury.

Systematic review and meta-analysis: Comparing hepatocellular and cholestatic patterns of drug-induced liver injury

Drug-induced liver injury (DILI) is a leading cause of death from acute liver failure (ALF). Hy's law warns that a hepatocellular pattern of injury accompanied by jaundice and normal alkaline phosphatase (ALP) levels is associated with a 10% or greater chance of progression to transplant or liver-related death. This meta-analysis of DILI studies evaluates acute and chronic outcomes of DILI according to clinical pattern of injury. We conducted a systematic search using electronic databases PubMed and EMBASE through to 8 March 2022. Our primary outcome was to compare acute outcomes including ALF, liver-related death, and liver transplant between patients experiencing hepatocellular, cholestatic, and mixed patterns of DILI. Our secondary outcome was to compare the rate of DILI chronicity between patients of these three differing patterns of injury. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random-effects model. Overall, 12 studies comprising 4290 patients were included. Patients with cholestatic DILI demonstrated similar rates of ALF (OR: 0.80, 95% CI: 0.46–1.40, p = 0.429) and liver-related death (OR: 0.92, 95% CI: 0.50–1.69, p = 0.792) compared to patients with hepatocellular DILI. Patients with cholestatic DILI were significantly more likely to experience chronicity compared to patients with hepatocellular DILI (OR: 2.53, 95% CI: 1.34–4.79, p = 0.004). Hy's law conceives severe DILI as an exclusive consequence of hepatocellular pattern of injury. Our results demonstrate that cholestatic injury can be associated with similarly poor rates of ALF and liver-related fatality, as well as higher rates of chronic DILI.