Models of Idiosyncratic Drug-Induced Liver Injury.

Drug-induced liver injury (DILI) is a leading cause of attrition during the early and late stages of drug development and after a drug is marketed. DILI is generally classified as either intrinsic or idiosyncratic. Intrinsic DILI is dose dependent and predictable (e.g., acetaminophen toxicity). However, predicting the occurrence of idiosyncratic DILI, which has a very low incidence and is associated with severe liver damage, is difficult because of its complex nature and the poor understanding of its mechanism. Considering drug metabolism and pharmacokinetics, we established experimental animal models of DILI for 14 clinical drugs that cause idiosyncratic DILI in humans, which is characterized by the formation of reactive metabolites and the involvement of both innate and adaptive immunity. On the basis of the biomarker data obtained from the animal models, we developed a cell-based assay system that predicts the potential risks of drugs for inducing DILI. These findings increase our understanding of the mechanisms of DILI and may help predict and prevent idiosyncratic DILI due to certain drugs.

Methods for causality assessment of idiosyncratic drug-induced liver injury.

The diagnosis of idiosyncratic drug-induced liver injury (DILI) is a challenging task due to the lack of specific features or definitive diagnostic tools. A minimum of clinical and pharmacological information is required, together with laboratory and imaging tests to exclude other causes of liver injury. Several standardized methods have been developed to support clinical judgement and establish causality assessment, the most widely used being the Roussel Uclaf Causality Assessment Method-RUCAM-and structured Expert Opinion. More recently, an evidence-based, revised RUCAM, Electronic Causality Assessment Method-RECAM-has been developed and, although still a work in progress, may replace RUCAM scoring in the future. International collaborative networks and ongoing research efforts are key to advancing biomarker qualification and validation and developing new in vitro patient-based methods that will help improve DILI diagnosis and move towards a personalized medicine approach.

Drug-induced liver injury (DILI) ascribed to non-steroidal anti-inflammatory drugs (NSAIDs) in the USA-Update with genetic correlations.

OBJECTIVE: To describe patients with NSAID-DILI, including genetic factors associated with idiosyncratic DILI. METHODS: In DILIN, subjects with presumed DILI are enrolled and followed for at least 6 months. Causality is adjudicated by a Delphic approach. HLA sequencing of multiethnic NSAID-DILI patients and HLA allele imputation of matching population controls were performed following overall, class and drug-based association analysis. Significant results were tested in a non-Hispanic White (NHW) case-control replication cohort. RESULTS: Between September 2004 and March 2022, causality was adjudicated in 2498, and 55 (41 [75%] women) were assessed as likely due to NSAIDs. Median age at onset was 55 y (range 22-83 y). Diclofenac was the causative drug in 29, celecoxib in 7, ibuprofen in 5, etodolac and meloxicam each in 4. Except for meloxicam and oxaprozin (n = 2), the liver injury was hepatocellular with median R 15-25. HLA-DRB1*04:03 and HLA-B*35:03 were significantly more frequent in NSAID-DILI patients than in non-NSAID DILI controls. Interestingly, 85% of the HLA-DRB1*04:03 carriers developed DILI due to the use of acetic acid derivative NSAIDs, supporting the hypothesis that HLA-DRB1*04:03 could be a drug and/or class risk factor. HLA-B*35:03 but not HLA-DRB1*04:03 association was confirmed in the independent NHW replication cohort, which was largely driven by diclofenac. CONCLUSIONS: Despite prevalent use, NSAID-DILI is infrequent in the United States. Diclofenac is the most commonly implicated, and adherence to warnings of risk and close observation are recommended. The increased frequency of HLA-B*35:03 and DRB1*04:03, driven by diclofenac, suggests the importance of immune-mediated responses.

Roadmap to DILI research in Europe. A proposal from COST action ProEuroDILINet.

In the current article the aims for a constructive way forward in Drug-Induced Liver Injury (DILI) are to highlight the most important priorities in research and clinical science, therefore supporting a more informed, focused, and better funded future for European DILI research. This Roadmap aims to identify key challenges, define a shared vision across all stakeholders for the opportunities to overcome these challenges and propose a high-quality research program to achieve progress on the prediction, prevention, diagnosis and management of this condition and impact on healthcare practice in the field of DILI. This will involve 1. Creation of a database encompassing optimised case report form for prospectively identified DILI cases with well-characterised controls with competing diagnoses, biological samples, and imaging data; 2. Establishing of preclinical models to improve the assessment and prediction of hepatotoxicity in humans to guide future drug safety testing; 3. Emphasis on implementation science and 4. Enhanced collaboration between drug-developers, clinicians and regulatory scientists. This proposed operational framework will advance DILI research and may bring together basic, applied, translational and clinical research in DILI.

Idiosyncratic gesture use in a mother-infant dyad in chimpanzees (Pan troglodytes schweinfurthii) in the wild.

One promising method to tackle the question, "In which modality did language evolve?" is by studying the ontogenetic trajectory of signals in human's closest living relatives, including chimpanzees (Pan troglodytes). Concerning gestures, current debates centre on four different hypotheses: "phylogenetic ritualization", "social transmission through imitation", "ontogenetic ritualization", and "social negotiation". These differ in their predictions regarding idiosyncratic gestures, making such occurrences a crucial area of investigation. Here, we describe a novel and potential idiosyncratic behaviour - 'hand-on-eye' - which was initially observed in one mother-infant dyad in a community of chimpanzees living in the wild. We systematically investigated the form, sequential organisation, intentionality, usage, function, and distribution of the behaviour over a five-year period. The results showed that 'hand-on-eye' was nearly exclusively deployed in a single mother-infant dyad, was accompanied by hallmarks of intentionality, and served to initiate or resume joint dorsal travel. Although the behaviour was observed once in each of three other mother-infant dyads, these lacked the same frequency and hallmarks of intentionality. 'Hand-on-eye' thus qualifies as an idiosyncratic gesture. The proposed developmental pathway gives support to both the "ontogenetic ritualization" and "social negotiation" hypotheses. It also stresses the crucial need for longitudinal approaches to tackle developmental processes that are triggered by unique circumstances and unfold over relatively long time windows.

Elucidating the Mechanisms Underlying Interindividual Differences in the Onset of Adverse Drug Reactions.

Idiosyncratic drug toxicities (IDTs) pose a significant challenge; they are marked by life-threatening adverse reactions that emerge aftermarket release and are influenced by intricate genetic and environmental variations. Recent genome-wide association studies have highlighted a strong correlation between specific human leukocyte antigen (HLA) polymorphisms and IDT onset. This review provides an overview of current research on HLA-mediated drug toxicities. In the last six years, HLA-transgenic (Tg) mice have been instrumental in advancing our understanding of these underlying mechanisms, uncovering systemic immune reactions that replicate human drug-induced immune stimulation. Additionally, the potential role of immune tolerance in shaping individual differences in adverse effects highlights its relevance to the interplay between HLA polymorphisms and IDTs. Although HLA-Tg mice offer valuable insights into systemic immune reactions, further exploration is essential to decipher the intricate interactions that lead to organ-specific adverse effects, especially in organs such as the skin or liver. Navigating the intricate interplay of HLA, which may potentially trigger intracellular immune responses, this review emphasizes the need for a holistic approach that integrates findings from both animal models and molecular/cellular investigations. The overarching goal is to enhance our comprehensive understanding of HLA-mediated IDTs and identify factors shaping individual variations in drug reactions. This review aims to facilitate the development of strategies to prevent severe adverse effects, address existing knowledge gaps, and provide guidance for future research initiatives in the field of HLA-mediated IDTs.

Uncovering the mechanism of troglitazone-mediated idiosyncratic drug-induced liver injury with individual-centric models.

Idiosyncratic drug-induced liver injury is a rare and unpredictable event. Deciphering its initiating-mechanism is a hard task as its occurrence is individual dependent. Thus, studies that utilize models that are not individual-centric might drive to a general mechanistic conclusion that is not necessarily true. Here, we use the individual-centric spheroid model to analyze the initiating-mechanism of troglitazone-mediated iDILI risk. Individual-centric spheroid models were generated using a proprietary cell educating technology. These educated spheroids contain hepatocytes, hepatic stellate cells, activated monocyte-derived macrophages, and dendritic cells under physiological conditions. We show that phases 1 and 2 drug-metabolizing enzymes were induced in an individual-dependent manner. However, we did not observe any association of DEMs induction and troglitazone (TGZ)-mediated iDILI risk. We analyzed TGZ-mediated iDILI and found that a 44-year-old male showed iDILI risk that is associated with TGZ-mediated suppression of IL-12 expression by autologous macrophages and dendritic cells. We performed a rescue experiment and showed that treatment of spheroids from this 44-year-old male with TGZ and recombinant IL-12 suppressed iDILI risk. We confirmed the mechanism in another 31-year-old female with iDILI risk. We demonstrate here that individual-centric spheroid are versatile models that allow to predict iDILI risk and to analyze a direct effect of the drug on activated macrophages and dendritic cells to uncover the initiating-mechanism of iDILI occurrence. This model opens perspectives for a personalized strategy to mitigate iDILI risk.

Trail using ants follow idiosyncratic routes in complex landscapes.

A large volume of research on individually navigating ants has shown how path integration and visually guided navigation form a major part of the ant navigation toolkit for many species and are sufficient mechanisms for successful navigation. One of the behavioural markers of the interaction of these mechanisms is that experienced foragers develop idiosyncratic routes that require that individual ants have personal and unique visual memories that they use to guide habitual routes between the nest and feeding sites. The majority of ants, however, inhabit complex cluttered environments and social pheromone trails are often part of the collective recruitment, organisation and navigation of these foragers. We do not know how individual navigation interacts with collective behaviour along shared trails in complex natural environments. We thus asked here if wood ants that forage through densely cluttered woodlands where they travel along shared trails repeatedly follow the same routes or if they choose a spread of paths within the shared trail. We recorded three long homing trajectories of 20 individual wood ants in their natural woodland habitat. We found that wood ants follow idiosyncratic routes when navigating along shared trails through highly complex visual landscapes. This shows that ants rely on individual memories for habitual route guidance even in cluttered environments when chemical trail information is available. We argue that visual cues are likely to be the dominant sensory modality for the idiosyncratic routes. These experiments shed new light on how ants, or insects in general, navigate through complex multimodal environments.

Evolved attitudes to risk and the demand for equity.

The equity premium puzzle refers to the observation that people invest far less in the stock market than is implied by measures of their risk aversion in other contexts. Here, we argue that light on this puzzle can be shed by the hypothesis that human risk attitudes were at least partly shaped by our evolutionary history. In particular, a simple evolutionary model shows that natural selection will, over the long haul, favor a greater aversion to aggregate than to idiosyncratic risk. We apply this model-via both a static model of portfolio choice and a dynamic model that allows for intertemporal tradeoffs-to show that an aversion to aggregate risk that is derived from biology may help explain the equity premium puzzle. The type of investor favored in our model would indeed invest less in equities than other common observations of risk-taking behavior from outside the stock market would imply, while engaging in reasonable tradeoffs over time.

An integrative lipidomics and transcriptomics study revealing Bavachin and Icariin synergistically induce idiosyncratic liver injury.

Objectives: Reports of traditional Chinese medicine (TCM)-related liver injury have increased over recent years; however, identifying susceptibility-related components and biomarkers remains challenging due to the heterogeneous nature of TCM and idiosyncratic drug-induced liver injury (IDILI). Psoraleae Fructus (PF) and Epimedii Folium (EF), commonly found in TCM prescriptions, have been implicated in IDILI, but their constituents and underlying mechanisms are poorly understood.Methods: In this study, we identified bavachin (Bav) and icariin (Ica) as susceptibility components for IDILI in PF and EF using a TNF-α-mediated mouse model. Lipidomics and transcriptomics were used to investigate their related mechanism.Results: Liver biochemistry and histopathology analyses revealed that co-exposure to Bav, Ica, and a non-toxic dose of TNF-α prestimulation induced significant liver injury, while Bav and Ica alone did not. Lipidomics identified seven differentially abundant metabolites in the Bav/Ica/TNF-α group compared to the Ica/TNF-α or Bav/TNF-α groups, mainly enriched in alpha-linolenic acid (ALA), arachidonic acid (AA), and linoleic acid (LA) metabolic pathways. Additionally, transcriptomics revealed 49 differentially expressed genes (DEGs) in the Bav/TNF-α vs Bav/Ica/TNF-α and Ica/TNF-α vs Bav/Ica/TNF-α groups, primarily associated with the PI3K/AKT/mTOR signaling pathway and sphingolipid metabolism. Integrative lipidomics and transcriptomics analyses identified significant positive correlations between five differential metabolites (DMs) - PC (O-16:0_14:1), PG (22:1_20:3), PI (16:0_14:1), PS (18:0_19:2), and TG (17:0_18:2_22:5) - and ten DEGs - Nr0b2, Btbd19, Btg2, Fam222a, Fam83f, Gtse1, Anln, Gja4, Srrm4, and Zfp13.Conslusions: Collectively, these results suggest that alterations in intracellular metabolism and gene expression levels may contribute to the synergistic induction of IDILI by the incompatible pair Bav and Ica in the presence of TNF-α.

Exploring Individual Variability in Drug-Induced Liver Injury (DILI) Responses through Metabolomic Analysis.

Drug-induced liver injury (DILI) is a serious adverse hepatic event presenting diagnostic and prognostic challenges. The clinical categorization of DILI into hepatocellular, cholestatic, or mixed phenotype is based on serum alanine aminotransferase (ALT) and alkaline phosphatase (ALP) values; however, this classification may not capture the full spectrum of DILI subtypes. With this aim, we explored the utility of assessing changes in the plasma metabolomic profiles of 79 DILI patients assessed by the RUCAM (Roussel Uclaf Causality Assessment Method) score to better characterize this condition and compare results obtained with the standard clinical characterization. Through the identification of various metabolites in the plasma (including free and conjugated bile acids and glycerophospholipids), and the integration of this information into predictive models, we were able to evaluate the extent of the hepatocellular or cholestatic phenotype and to assign a numeric value with the contribution of each specific DILI sub-phenotype into the patient's general condition. Additionally, our results showed that metabolomic analysis enabled the monitoring of DILI variability responses to the same drug, the transitions between sub-phenotypes during disease progression, and identified a spectrum of residual DILI metabolic features, which can be overlooked using standard clinical diagnosis during patient follow-up.

[Pseudo-targeted metabolomics study of immune stress-mediated idiosyncratic liver injury induced by synergistic effects of bavachin and epimedin B].

Chinese patent medicine preparations containing Epimedii Folium and Psoraleae Fructus have been associated with the occurrence of idiosyncratic drug-induced liver injury(IDILI). However, the specific toxic biomarkers and mechanisms underlying these effects remain unclear. This study aimed to comprehensively assess the impact of bavachin and epimedin B, two principal consti-tuents found in Psoraleae Fructus and Epimedii Folium, on an IDILI model induced by tumor necrosis factor-α(TNF-α) treatment, both in vitro and in vivo. To evaluate the extent of liver injury, various parameters were assessed. Lactate dehydrogenase(LDH) release in the cell culture supernatant, as well as the levels of alanine aminotransferase(ALT) and aspartate transaminase(AST) in mouse plasma were measured. Additionally, histological analysis employing hematoxylin-eosin staining was performed to observe liver tissue changes indicative of the severity of liver injury. Furthermore, a pseudo-targeted metabolomics approach was employed, followed by multivariate analysis, to identify differential metabolites. These identified metabolites were subsequently subjected to Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analysis. The results showed that at the cellular level, after 2 hours of TNF-α stimulation, bavachin significantly increased the release of LDH in HepG2 cells compared to the normal group and the group treated alone; after the combination of bavachin and epimedin B, the release of LDH further significantly increased on the original basis. Similarly, although the individual or combination treatments of bavachin and epimedin B did not induce liver injury in normal mice, the combination of both drugs induced marked liver injury in TNF-α treated mice, leading to a significant elevation in plasma AST and ALT levels and substantial infiltration of inflammatory immune cells in the liver tissue. Pseudo-targeted metabolomics analysis identified seven common differential metabolites. Among these, D-glucosamine-6-phosphate, N1-methyl-2-pyridone-5-carboxamide, 17beta-nitro-5a-androstane, irisolidone-7-O-glucuronide, and N-(1-deoxy-1-fructosyl) valine emerged as potential biomarkers, with an area under the curve(AUC) exceeding 0.9. Furthermore, our results suggest that the metabolism of nicotinic acid and nicotinamide, as well as the linoleic acid metabolic pathway, may play pivotal roles in bavachin and epimedin B-induced IDILI. In conclusion, within an immune-stressed environment mediated by TNF-α, bavachin and epimedin B appear to induce IDILI through disruptions in metabolic processes.

Single Idiosyncratic Ionic Generator Working in Iso-Osmotic Solutions Via Ligand Confined Assembled in Gaps Between Nanosheets.

Numerous reported bioinspired osmotic energy conversion systems employing cation-/anion-selective membranes and solutions with different salinity are actually far from the biological counterpart. The iso-osmotic power generator with the specific ionic permselective channels (e.g., K+ or Na+ channels) which just allow specific ions to get across and iso-osmotic solutions still remain challenges. Inspired by nature, we report a bioinspired K+ -channel by employing a K+ selective ligand, 1,1,1-tris{[(2'-benzylaminoformyl)phenoxy]methyl}ethane (BMP) and graphene oxide membrane. Specifically, the K+ and Na+ selectivity of the prepared system could reach up to ≈17.8, and the molecular dynamics simulation revealed that the excellent permselectivity of K+ mainly stemmed from the formed suitable channel size. Thus, we assembled the K+ -selective iso-osmotic power generator (KSIPG) with the power density up to ≈15.1 mW/m2 between equal concentration solutions, which is higher than traditional charge-selective osmotic power generator (CSOPG). The proposed strategy has well shown the realizable approach to construct single-ion selective channels-based highly efficient iso-osmotic energy conversion systems and would surely inspire new applications in other fields, including self-powered systems and medical materials, etc.

A two-sample robust Bayesian Mendelian Randomization method accounting for linkage disequilibrium and idiosyncratic pleiotropy with applications to the COVID-19 outcomes.

Mendelian randomization (MR) is a statistical method exploiting genetic variants as instrumental variables to estimate the causal effect of modifiable risk factors on an outcome of interest. Despite wide uses of various popular two-sample MR methods based on genome-wide association study summary level data, however, those methods could suffer from potential power loss or/and biased inference when the chosen genetic variants are in linkage disequilibrium (LD), and also have relatively large direct effects on the outcome whose distribution might be heavy-tailed which is commonly referred to as the idiosyncratic pleiotropy phenomenon. To resolve those two issues, we propose a novel Robust Bayesian Mendelian Randomization (RBMR) model that uses the more robust multivariate generalized t$t$ -distribution to model such direct effects in a probabilistic model framework which can also incorporate the LD structure explicitly. The generalized t$t$ -distribution can be represented as a Gaussian scaled mixture so that our model parameters can be estimated by the expectation maximization (EM)-type algorithms. We compute the standard errors by calibrating the evidence lower bound using the likelihood ratio test. Through extensive simulation studies, we show that our RBMR has robust performance compared with other competing methods. We further apply our RBMR method to two benchmark data sets and find that RBMR has smaller bias and standard errors. Using our proposed RBMR method, we find that coronary artery disease is associated with increased risk of critically ill coronavirus disease 2019. We also develop a user-friendly R package RBMR (https://github.com/AnqiWang2021/RBMR) for public use.

MRCIP: a robust Mendelian randomization method accounting for correlated and idiosyncratic pleiotropy.

Mendelian randomization (MR) is a powerful instrumental variable (IV) method for estimating the causal effect of an exposure on an outcome of interest even in the presence of unmeasured confounding by using genetic variants as IVs. However, the correlated and idiosyncratic pleiotropy phenomena in the human genome will lead to biased estimation of causal effects if they are not properly accounted for. In this article, we develop a novel MR approach named MRCIP to account for correlated and idiosyncratic pleiotropy simultaneously. We first propose a random-effect model to explicitly model the correlated pleiotropy and then propose a novel weighting scheme to handle the presence of idiosyncratic pleiotropy. The model parameters are estimated by maximizing a weighted likelihood function with our proposed PRW-EM algorithm. Moreover, we can also estimate the degree of the correlated pleiotropy and perform a likelihood ratio test for its presence. Extensive simulation studies show that the proposed MRCIP has improved performance over competing methods. We also illustrate the usefulness of MRCIP on two real datasets. The R package for MRCIP is publicly available at https://github.com/siqixu/MRCIP.

Tricyclic antidepressants induce liver inflammation by targeting NLRP3 inflammasome activation.

BACKGROUND: Idiosyncratic drug-induced liver injury (IDILI) is common in hepatology practices and, in some cases, lethal. Increasing evidence show that tricyclic antidepressants (TCAs) can induce IDILI in clinical applications but the underlying mechanisms are still poorly understood. METHODS: We assessed the specificity of several TCAs for NLRP3 inflammasome via MCC950 (a selective NLRP3 inhibitor) pretreatment and Nlrp3 knockout (Nlrp3-/-) BMDMs. Meanwhile, the role of NLRP3 inflammasome in the TCA nortriptyline-induced hepatotoxicity was demonstrated in Nlrp3-/- mice. RESULTS: We reported here that nortriptyline, a common TCA, induced idiosyncratic hepatotoxicity in a NLRP3 inflammasome-dependent manner in mildly inflammatory states. In parallel in vitro studies, nortriptyline triggered the inflammasome activation, which was completely blocked by Nlrp3 deficiency or MCC950 pretreatment. Furthermore, nortriptyline treatment led to mitochondrial damage and subsequent mitochondrial reactive oxygen species (mtROS) production resulting in aberrant activation of the NLRP3 inflammasome; a selective mitochondrial ROS inhibitor pretreatment dramatically abrogated nortriptyline-triggered the NLRP3 inflammasome activation. Notably, exposure to other TCAs also induced aberrant activation of the NLRP3 inflammasome by triggering upstream signaling events. CONCLUSION: Collectively, our findings revealed that the NLRP3 inflammasome may act as a crucial target for TCA agents and suggested that the core structures of TCAs may contribute to the aberrant activation of NLRP3 inflammasome induced by them, an important factor involved in the pathogenesis of TCA-induced liver injury. Video Abstract.

Drug induced liver injury - a 2023 update.

Drug-Induced Liver Injury (DILI) constitutes hepatic damage attributed to drug exposure. DILI may be categorized as hepatocellular, cholestatic or mixed and might also involve immune responses. When DILI occurs in dose-dependent manner, it is referred to as intrinsic, while if the injury occurs spontaneously, it is termed as idiosyncratic. This review predominately focused on idiosyncratic liver injury. The established molecular mechanisms for DILI include (1) mitochondria dysfunction, (2) increased reactive oxygen species levels, (3) presence of elevated apoptosis and necrosis, (4) and bile duct injuries associated with immune mediated pathways. However, it should be emphasized that the underlying mechanisms responsible for DILI are still unknown. Prevention strategies are critical as incidences occur frequently, and treatment options are limited once the injury has developed. The aim of this review was to utilize retrospective cohort studies from across the globe to gain insight into epidemiological patterns. This review considers (1) what is currently known regarding the mechanisms underlying DILI, (2) discusses potential risk factors and (3) implications of the coronavirus pandemic on DILI presentation and research. Future perspectives are also considered and discussed and include potential new biomarkers, causality assessment and reporting methods.

Clinical and Liver Biochemistry Phenotypes, and Outcome in 133 Patients with Anti-seizure Drug-Induced Liver Injury.

AIMS AND OBJECTIVE: Anti-seizure drugs that cause idiosyncratic drug-induced liver injury (DILI) are an important cause of morbidity and mortality in individuals exposed to these drugs. The clinical and demographic characteristics, the liver injury pattern, the outcome, and the agents responsible for hepatotoxicity have not been thoroughly studied. We investigated the aforementioned characteristics in a large cohort of DILI registry patients. METHODS: Patients with anti-seizure DILI were studied from a large single-center DILI registry between 1998 and 2021. DILI was defined by international working group criteria with at least a probable relation with RUCAM. Immunoallergic features and organ-specific contribution to outcome were investigated. RESULTS: Anti-seizure drugs accounted for 133 patients (12.5%) among 1067 patients with idiosyncratic DILI. Compared to other agents, patients with anti-seizure DILI were younger (31 vs 41 years; p = 0.31), were more often females (52% vs 46%; p = 0.19) and had a lower frequency of jaundice (41% vs 59%, p = 0.001), MELD score (14.5 vs 16.5; p = 0.02) and mortality (9.8% vs 15.7%, p = 0.03). Anti-seizure DILI exhibited a greater frequency of hypersensitivity skin rashes (75% vs 22%, p < 0.001), including DRESS (51% vs 13%, p < 0.001) and SJS/TEN (19% vs1%, p < 0.001). A total of 18 different anti-seizure agents were responsible for DILI, largely contributed by carbamazepine (n = 36), phenytoin (n = 71), phenobarbitone (n = 8) and valproate (n = 14) which accounted for 89% of cases and 85% of 13 deaths. CONCLUSIONS: Anti-seizure DILI are caused predominantly by first generation drugs. Newer agents account for < 10% of cases. Hypersensitivity reaction is the most common phenotypic presentation. Both severity and mortality are lower with anti-seizure DILI.

The Role of Myeloperoxidase in Clozapine-Induced Inflammation: A Mechanistic Update for Idiosyncratic Drug-Induced Agranulocytosis.

The risk of idiosyncratic drug-induced agranulocytosis (IDIAG) markedly constrains the use of clozapine, a neuroleptic with unparalleled efficacy. Most clozapine patients experience an early inflammatory response, likely a necessary step in IDIAG onset. However, most patients do not progress to IDIAG, presumably because of the requirement of specific human leukocyte antigen (HLA) haplotypes, T cell receptors, and other unknown factors. We established that clozapine activates inflammasomes and that myeloperoxidase bioactivation of clozapine generates neoantigens, but the connection between these early mechanistic events remained unknown and, thus, was the aim of this work. We found that the myeloperoxidase inhibitor PF-1355 attenuated myeloperoxidase activity in phorbol myristate acetate (PMA)-differentiated THP-1 macrophages, and it also attenuated clozapine-induced release of inflammatory mediators (e.g., IL-1ß, CXCL1, and C-reactive protein). In vivo, pretreatment of Sprague Dawley rats with PF-1355 significantly attenuated clozapine-induced increases in neutrophil mobilization from the bone marrow to the blood and spleen, as determined using differential blood counts and flow cytometry. Moreover, the clozapine-triggered release of inflammatory mediators (e.g., IL-1ß, calprotectin, CXCL1, and α-1-acid glycoprotein) from the liver, spleen, and bone marrow was dampened by myeloperoxidase inhibition. These data support the working hypothesis that oxidation of clozapine to a reactive metabolite by myeloperoxidase is critical for induction of the inflammatory response to clozapine. Ultimately, a better mechanistic understanding of the early events involved in the immune response to clozapine may elucidate ways to prevent IDIAG, enabling safer, more frequent therapeutic use of this and potentially other highly efficacious drugs.

Molecular and Clinical Links between Drug-Induced Cholestasis and Familial Intrahepatic Cholestasis.

Idiosyncratic Drug-Induced Liver Injury (iDILI) represents an actual health challenge, accounting for more than 40% of hepatitis cases in adults over 50 years and more than 50% of acute fulminant hepatic failure cases. In addition, approximately 30% of iDILI are cholestatic (drug-induced cholestasis (DIC)). The liver's metabolism and clearance of lipophilic drugs depend on their emission into the bile. Therefore, many medications cause cholestasis through their interaction with hepatic transporters. The main canalicular efflux transport proteins include: 1. the bile salt export pump (BSEP) protein (ABCB11); 2. the multidrug resistance protein-2 (MRP2, ABCC2) regulating the bile salts' independent flow by excretion of glutathione; 3. the multidrug resistance-1 protein (MDR1, ABCB1) that transports organic cations; 4. the multidrug resistance-3 protein (MDR3, ABCB4). Two of the most known proteins involved in bile acids' (BAs) metabolism and transport are BSEP and MDR3. BSEP inhibition by drugs leads to reduced BAs' secretion and their retention within hepatocytes, exiting in cholestasis, while mutations in the ABCB4 gene expose the biliary epithelium to the injurious detergent actions of BAs, thus increasing susceptibility to DIC. Herein, we review the leading molecular pathways behind the DIC, the links with the other clinical forms of familial intrahepatic cholestasis, and, finally, the main cholestasis-inducing drugs.