Drug-induced liver disorders: implications for drug development and regulation

Liver function tests, CD4+ counts, and viral load among people living with HIV on dolutegravir compared to efavirenz-based cART; a comparative cross-sectional study

Background

Recently, dolutegravir-based therapy has become the first-line treatment when compared to others. However, dolutegravir-associated side effects in the liver and levels of efficacy haven't been addressed yet in underdeveloped countries such as Ethiopia.

Objective

The purpose of this study was to compare liver function tests, CD4+ counts, and viral load among people living with HIV on dolutegravir and efavirenz-based antiretroviral regimens at Debre Markos Comprehensive Specialized Hospital in Northwest Ethiopia.

Methods

An institutional-based comparative cross-sectional study was carried out from May 20 to July 10, 2020. An equal number of dolutegravir and efavirenz-prescribed patients (n = 53 each) for 6 months and above were included, and a judgmental sampling technique was used. A comparison of categorical and continuous parameters was analyzed with chi-square and an independent t-test, respectively, using SPSS version 26. A multivariable logistic regression was conducted and considered statistically significant at a p-value of <0.05.

Results

The magnitude of liver enzyme (AST/ALT) abnormalities was 22.4 % (12/53) and 30.2 % (16/53) among dolutegravir- and efavirenz-prescribed patients, respectively. The dolutegravir group had significantly higher mean CD4+ counts than the efavirenz group (589.40 ± 244.38 vs. 450.64 ± 203.54 cell/mm3; p = 0.002). The efavirenz group had a significantly higher mean viral load than the dolutegravir group (783.83 ± 476.82 vs. 997.98 ± 439.11 cp/ml; p = 0.032). There was a statistically insignificant difference in AST (p = 0.709) or ALT (p = 0.687) between dolutegravir and efavirenz-based regimens. The multivariable logistic regression analysis revealed that BMI ≥25 kg/m2 was associated with liver enzyme abnormalities (AOR = 6.60, 95 % CI: 1.17, 42.82).

Conclusion

A dolutegravir-based regimen was more likely to result in patients achieving higher efficacy for viral suppression and a CD4+ count increase. Although the differences were statistically insignificant, the mean AST and ALT levels were marginally higher in efavirenz-treated groups than in dolutegravir-treated groups.

Role of microsomal metabolism in bromfenac-induced cytotoxicity

This study delves into the intricate mechanisms underlying drug-induced liver injury (DILI) with a specific focus on bromfenac, the withdrawn nonsteroidal anti-inflammatory drug. DILI is a pervasive concern in drug development, prompting market withdrawals and posing significant challenges to healthcare. Despite the withdrawal of bromfenac due to DILI, the exact role of its microsomal metabolism in inducing hepatotoxicity remains unclear. Herein, employing HepG2 cells with human liver microsomes and UDP-glucuronic acid (UDPGA), our investigation revealed a substantial increase in bromfenac-induced cytotoxicity in the presence of UDPGA, pointing to the significance of UDP-glucuronosyltransferase (UGT)-dependent metabolism in augmenting toxicity. Notably, among the recombinant UGTs examined, UGT2B7 emerged as a pivotal enzyme in the metabolic activation of bromfenac. Metabolite identification studies disclosed the formation of reactive intermediates, with bromfenac indolinone (lactam) identified as a potential mediator of hepatotoxic effects. Moreover, in cytotoxicity experiments, the toxicity of bromfenac lactam exhibited a 34-fold increase, relative to bromfenac. The toxicity of bromfenac lactam was mitigated by nicotinamide adenine dinucleotide phosphate-dependent metabolism. This finding underscores the role of UGT-dependent metabolism in generating reactive metabolites that contribute to the observed hepatotoxicity associated with bromfenac. Understanding these metabolic pathways and the involvement of specific enzymes, such as UGT2B7, provides crucial insights into the mechanisms of bromfenac-induced liver injury. In conclusion, this research sheds light on the metabolic intricacies leading to cytotoxicity induced by bromfenac, especially emphasizing the role of UGT-dependent metabolism and the formation of reactive intermediates like bromfenac lactam. These findings offer insight into the mechanistic basis of DILI and emphasize the importance of understanding metabolism-mediated toxicity.

Discovery of a Novel Lidocaine Metabolite by Human Liver Microsome and Identification of Microbial Species Which Produces the Same Metabolite

Preparation of drug metabolites at the milligram scale is essential for determining the structure and toxicity of drug metabolites. However, their preparation using recombinant proteins and human liver microsomes (HLM) is often difficult because of technical and ethical issues. Reproducing human drug metabolism in food-derived microorganisms may be useful for overcoming these challenges. In this study, we identified an unknown metabolite of the anaesthetic drug lidocaine, which is metabolised by HLM. By screening for lidocaine metabolic activity in five types of foods (blue cheese, shiitake mushroom, natto, yoghurt, and dry yeast), we found that bacteria isolated from natto reproduced the lidocaine metabolic reaction that occurs in HLM. A fraction containing the unknown lidocaine metabolite was prepared through mass cultivation of a Bacillus subtilis standard strain, ethyl acetate extraction, open column chromatography, and HPLC purification. We identified the unknown metabolite as 3-(2,6-dimethylphenyl)-1-ethyl-2-methyl-4-imidazolidinone using NMR. Our results showed that food-derived microorganisms can produce large amounts of human drug metabolites via large-scale cultivation. Additionally, food microorganisms that can reproduce drug metabolism in humans can be used to examine drug metabolites at a low cost and without ethical issues.

The cyclin-dependent kinase inhibitor abemaciclib-induced hepatotoxicity: Insight on the molecular mechanisms in HepG2/THP-1 co-culture model

Drug-induced liver injury (DILI) is one of the widespread causes of liver injury and immune system plays important role. Abemaciclib (ABE) is a cyclin-dependent kinase inhibitor used as monotherapy or combination therapy in the treatment of breast cancer. Like other kinase inhibitors, the underlying mechanisms of ABE-induced hepatotoxicity are not completely known yet. In the current study, hepatotoxicity of ABE was evaluated with HepG2/THP-1 co-culture model which has been developed in recent years for the evaluation of DILI potential. Following ABE treatment, oxidative stress, mitochondrial damage, cytokine secretion levels, apoptotic/necrotic cell death were determined. According to our results, ROS production along with GSH depletion was observed in HepG2 cells after ABE treatment. ABE promoted secretion of pro-inflammatory mediators (TNF-α and MCP-1) and declined anti-inflammatory cytokine IL-10 release. Besides, NFKβ and JNK1 protein expression levels increased following ABE treatment. ABE enhanced intracellular calcium levels, induced early apoptotic and necrotic cell deaths in HepG2 cells. Furthermore, the changes in some mitochondrial parameters including a reducement in intracellular ATP levels and complex V activity; hyperpolarized mitochondrial membrane potential and enhanced mitochondrial ROS levels were observed, whereas mitochondrial mass did not show any differences after ABE treatments. Therefore, ABE-induced hepatotoxic effects is probably via oxidative stress, inflammatory response and necrotic cell death rather than direct mitochondrial toxicity. In conclusion; the study makes a significant contribution to strengthening the infrastructure we have on in vitro toxicity mechanism evaluations, which are the basis of preclinical toxicity studies.

Review of human risk factors for idiosyncratic drug-induced liver injury: latest advances and future goals

INTRODUCTION

Idiosyncratic drug-induced liver injury (DILI) is a common cause of acute liver injury and can lead to death from acute liver failure or require liver transplantation. Although the total burden of liver injury is high, the frequency of DILI caused by specific agents is often low. As the liver injury is by per definition idiosyncratic, the prediction of which patients will develop liver injury from specific drugs is currently a very difficult challenge.

AREAS COVERED

The current paper highlights the most important studies on prediction of DILI published in 2019-2023, including studies on genetic, metabolomic, and demographic risk factors, concomitant medication, and the role of comorbid liver diseases. Risk stratification using demographic, metabolomic, and multigenetic risk factors is discussed.

EXPERT OPINION

Great advances have been made in identifying genetic risk factors for DILI. Combining these risk factors with demographic information and other biomarkers into multigenetic risk models might become highly useful in risk stratifying patients exposed to DILI. However, a more detailed mapping of genetic risk factors is needed. Results of these studies need to be validated in the selected ethnic groups before applicability and cost-effectiveness can be determined.

Protective role of resveratrol against VCM-induced hepatotoxicity in male wistar rats

Background: Vancomycin is a glycopeptide antibiotic with a high risk of acute liver injury. Resveratrol is believed to protect the liver against toxicity. Aim: To investigate the ability of resveratrol to attenuate vancomycin-induced liver toxicity in rats injected with vancomycin. Method: Twenty-four adult male Wistar rats were distributed into three groups. The control group received only a vehicle, while the treated group received either vancomycin 200 (mg/kg, i. p.) only or vancomycin (200 mg/kg, i. p.) with resveratrol (20 mg/kg, oral gavage). All groups received their dose once daily for 7 days. Hepatic damage was assessed by measuring biochemical parameter levels in serum, aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH). Also, antioxidants and inflammation biomarkers such as Interleukin-6 (IL-6), malondialdehyde (MDA), nitric oxide (NO), and glutathione (GSH) were measured. Furthermore, the vancomycin-induced pathological changes in the liver were evaluated by histopathological studies. Results: In the vancomycin-treated group, hepatic serum biomarkers such as AST, ALT, ALP, IL-6, and MDA were elevated, while NO and GSH were depleted. However, resveratrol co-treatment with vancomycin prevented the elevation of AST, ALT, ALP, IL-6, and MDA and it protected the liver from NO and GSH depletion. Also, regarding vancomycin-induced degeneration of hepatocytes, resveratrol co-treatment with vancomycin prevented such degeneration and improved mononuclear cells in the liver. Conclusion: The results showed that oral administration of resveratrol has a significant hepatoprotective effect against vancomycin-induced hepatotoxicity.

Synthesis, Molecular Docking, and Preclinical Evaluation of a New Succinimide Derivative for Cardioprotective, Hepatoprotective and Lipid-Lowering Effects

Cardiac and hepatotoxicities are major concerns in the development of new drugs. Better alternatives to other treatments are being sought to protect these vital organs from the toxicities of these pharmaceuticals. In this regard, a preclinical study is designed to investigate the histopathological effects of a new succinimide derivative (Comp-1) on myocardial and liver tissues, and the biochemical effects on selected cardiac biomarkers, hepatic enzymes, and lipid profiles. For this, an initially lethal/toxic dose was determined, followed by a grouping of selected albino rats into five groups (each group had n = 6). The control group received daily oral saline for 8 days. The 5-FU (5-Fluorouracil) group received oral saline daily for 8 days, added with the administration of a single dose of 5-FU (150 mg/kg I.P.) on day 5 of the study. The atenolol group received oral atenolol (20 mg/kg) for 8 days and 5-FU (150 mg/kg I.P.) on day 5 of the protocol. Similarly, two groups of rats treated with test compound (Comp-1) were administered with 5 mg/kg I.P. and 10 mg/kg I.P. for 8 days, followed by 5-FU (150 mg/kg I.P.) on day 5. Toxicity induced by 5-FU was manifested by increases in the serum creatinine kinase myocardial band (CK-MB), troponin I (cTnI) and lactate dehydrogenase (LDH), lipid profile, and selected liver enzymes, including ALP (alkaline phosphatase), ALT (alanine transaminase), AST (aspartate aminotransferase), BT (bilirubin total), and BD (direct bilirubin). These biomarkers were highly significantly decreased after the administration of the mentioned doses of the test compound (5 mg/kg and 10 mg/kg). Similarly, histological examination revealed cardiac and hepatic tissue toxicity by 5-FU. However, those toxic effects were also significantly recovered/improved after the administration of Comp-1 at the said doses. This derivative showed dose-dependent effects and was most effective at a dose of 10 mg/kg body weight. Binding energy data computed via docking simulations revealed that our compound interacts toward the human beta2-adrenergic G protein-coupled receptor (S = −7.89 kcal/mol) with a slight stronger affinity than the calcium channel T-type (S = −7.07 kcal/mol). In conclusion, the histological and biochemical results showed that the test compound (Comp-1) had prominent cardioprotective, hepatoprotective, and lipolytic effects against 5-FU-induced toxicity in the subjected animal model.

Bio-activation of simeprevir in liver microsomes and characterization of its glutathione conjugates by liquid chromatography coupled to ultrahigh-resolution quadrupole time-of-flight mass spectrometry

Liquid chromatography coupled to a triple quadrupole and, alternatively, to an ultrahigh-resolution quadrupole time-of-flight (UHR-QqTOF) mass spectrometers was used to collect qualitative and quantitative information from incubations of the anti-hepatitis C drug simeprevir with human and rat liver microsomes, respectively, supplemented with NADPH and glutathione. For this, different chromatographic methods using two different chromatographic columns, Kinetex® 2.6 µm C₁₈ (50 × 3 mm) and Atlantis T3 (100 Å, 3 µm, 4.6 mm × 150 mm), have been employed. For determination and structural characterization of the reactive metabolites, we used information obtained from high-resolution mass spectrometry, namely accurate mass data to calculate the elemental composition, accurate MS/MS fragmentation patterns for confirmation of structural proposals, and the high mass spectral resolution to eliminate false-positive peaks. In this study, the use of high-resolution mass spectrometry (HR-MS) enabled the identification of 19 simeprevir metabolites generated by O- respectively N-demethylation, oxidation, dehydrogenation, hydrolysis, and formation of glutathione conjugates. The in silico study provides insights into the sites of simeprevir most amenable to reactions involving cytochrome P₄₅₀. The developed methods have been successfully applied to analyze simeprevir and its metabolites simultaneously; based on this data, potential metabolic pathways of simeprevir are discussed. In general, the obtained results demonstrate that simeprevir is susceptible to form reactive simeprevir-glutathione adducts and cyclopropansulfonamide, which may explain the implication of simeprevir in idiosyncratic adverse drug reactions (IADRs) or hepatotoxicity.

Liver Injury Associated with Metamizole Exposure: Features of an Underestimated Adverse Event

INTRODUCTION AND OBJECTIVE

The potential of metamizole to cause drug-induced liver injury (DILI) has received increasing attention. We investigated the distinguishing features of a case series comprising 32 patients with suspected metamizole-induced DILI.

METHODS

For the current analysis, 32 of 238 patients with DILI included in our prospective study on drugs potentially causing DILI were included. Diagnosis of DILI was based on expert opinion and RUCAM (Roussel Uclaf Causality Assessment Method) score and supported by an in vitro test using monocyte-derived hepatocyte-like cells.

RESULTS

Suspected metamizole-DILI was characterised by a female predominance, hepatocellular pattern of injury, high proportion of antinuclear antibody positivity, and predominance of eosinophilic cell infiltration and necrosis in the histopathological analysis. With 22%, a high proportion of these metamizole-associated liver injury cases developed acute liver failure, which was characterised by a longer latency of metamizole use and more pronounced liver biochemistry abnormalities at onset and peak levels. Furthermore, jaundice was a common finding in the metamizole-associated liver injury cases with 66% presenting with peak bilirubin levels of 3 mg/dL or higher, which was associated with a worse outcome and a higher frequency of acute liver failure.

CONCLUSIONS

Our analysis of a well-characterised DILI cohort further supports the potential of metamizole causing DILI and provides important features for the establishment of a signature pattern of liver injury observed in patients treated with metamizole.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT02353455.

Mechanism of hepatotoxicity of first-line tyrosine kinase inhibitors: Gefitinib and afatinib

AIMS

Both gefitinib and afatinib are epidermal growth factor tyrosine kinase inhibitors (EGFR-TKI) in the treatment of non-small cell lung cancer (NSCLC). It has been reported that gefitinib and afatinib could cause hepatotoxicity during the clinic treatment, therefore it is critical to investigate their hepatotoxicity systematically. In this study, zebrafish (Danio rerio) were used as model animals to compare the hepatotoxicity and their toxic mechanism.

MAIN METHODS

The zebrafish transgenic line [Tg (fabp10a: dsRed; ela3l:EGFP) was used in this study. After larvae developed at 3 days post fertilization (dpf), they were put into different concentrations of gefitinib and afatinib. At 6 dpf, the viability, liver area, fluorescence intensity, histopathology, apoptosis, transaminase reflecting liver function, the absorption of yolk sac, and the expression of relative genes were observed and analyzed respectively.

KEY FINDINGS

Both gefitinib and afatinib could induce the larvae hepatotoxicity dose-dependently. Based on the liver morphology, histopathology, apoptosis and function assessments, gefitinib showed higher toxicity, causing more serious liver damage. Both gefitinib and afatinib caused abnormal expressions of genes related to endoplasmic reticulum stress (ERS) pathway and apoptosis. For example, jnk, perk, bip, chop, ire1, bid, caspase3 and caspase9 were up-regulated, while xbp1s, grp78, bcl-2/bax, and caspase8 were down-regulated. The hepatotoxicity difference of gefitinib and afatinib might be due to the different expression level of related genes.

Modeling the Bioactivation and Subsequent Reactivity of Drugs

Electrophilically reactive drug metabolites are implicated in many adverse drug reactions. In this mechanism-termed bioactivation-metabolic enzymes convert drugs into reactive metabolites that often conjugate to nucleophilic sites within biological macromolecules like proteins. Toxic metabolite-product adducts induce severe immune responses that can cause sometimes fatal disorders, most commonly in the form of liver injury, blood dyscrasia, or the dermatologic conditions toxic epidermal necrolysis and Stevens-Johnson syndrome. This study models four of the most common metabolic transformations that result in bioactivation: quinone formation, epoxidation, thiophene sulfur-oxidation, and nitroaromatic reduction, by synthesizing models of metabolism and reactivity. First, the metabolism models predict the formation probabilities of all possible metabolites among the pathways studied. Second, the exact structures of these metabolites are enumerated. Third, using these structures, the reactivity model predicts the reactivity of each metabolite. Finally, a feedfoward neural network converts the metabolism and reactivity predictions to a bioactivation prediction for each possible metabolite. These bioactivation predictions represent the joint probability that a metabolite forms and that this metabolite subsequently conjugates to protein or glutathione. Among molecules bioactivated by these pathways, we predicted the correct pathway with an AUC accuracy of 89.98%. Furthermore, the model predicts whether molecules will be bioactivated, distinguishing bioactivated and nonbioactivated molecules with 81.06% AUC. We applied this algorithm to withdrawn drugs. The known bioactivation pathways of alclofenac and benzbromarone were identified by the algorithm, and high probability bioactivation pathways not yet confirmed were identified for safrazine, zimelidine, and astemizole. This bioactivation model-the first of its kind that jointly considers both metabolism and reactivity-enables drug candidates to be quickly evaluated for a toxicity risk that often evades detection during preclinical trials. The XenoSite bioactivation model is available at http://swami.wustl.edu/xenosite/p/bioactivation.

Integration of human cell lines gene expression and chemical properties of drugs for Drug Induced Liver Injury prediction

MOTIVATION

Drug-induced liver injury (DILI) is one of the primary problems in drug development. Early prediction of DILI can bring a significant reduction in the cost of clinical trials. In this work we examined whether occurrence of DILI can be predicted using gene expression profile in cancer cell lines and chemical properties of drugs.

METHODS

We used gene expression profiles from 13 human cell lines, as well as molecular properties of drugs to build Machine Learning models of DILI. To this end, we have used a robust cross-validated protocol based on feature selection and Random Forest algorithm. In this protocol we first identify the most informative variables and then use them to build predictive models. The models are first built using data from single cell lines, and chemical properties. Then they are integrated using Super Learner method with several underlying methods for integration. The entire modelling process is performed using nested cross-validation.

RESULTS

We have obtained weakly predictive ML models when using either molecular descriptors, or some individual cell lines (AUC ∈(0.55-0.61)). Models obtained with the Super Learner approach have a significantly improved accuracy (AUC=0.73), which allows to divide substances in two categories: low-risk and high-risk.

Composite ammonium glycyrrhizin has hepatoprotective effects in chicken hepatocytes with lipopolysaccharide/enrofloxacin-induced injury

Composite ammonium glycyrrhizin (CAG) has anti-inflammatory activity. Lipopolysaccharide (LPS) and enrofloxacin (ENR) induce liver damage; however, the mechanism underlying LPS/ENR-induced hepatic injury remains to be elucidated. In the present study, the mechanism of LPS/ENR-induced liver injury was investigated in vitro and the protective effects of CAG were also evaluated. Primary chicken hepatocytes were isolated and a model of LPS/ENR-induced hepatocyte injury was established. mRNA and protein expression levels were evaluated by reverse transcription-quantitative polymerase chain reaction and western blot, respectively. LPS/ENR exposure significantly increased supernatant aspartate aminotransferase (AST) and alanine aminotransferase (ALT). In the LPS/ENR-treated group, glutathione (GSH) and the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities were significantly increased. Flow cytometry results revealed that the apoptotic rate significantly increased in the LPS/ENR-treated group compared with the control, while treatment with CAG given 24 h prior to LPS/ENR caused a significant decrease in the apoptotic rate compared with the model group. Furthermore, CAG treatment reversed LPS/ENR-associated alterations in the mRNA and protein expression of Caspase-3, apoptosis regulator Bcl-2 (Bcl-2) and Bcl-2 associated X-protein. The mitochondrial membrane potential significantly decreased and the mitochondrial microstructure was notably altered following exposure to LPS/ENR compared with the control. In conclusion, these results suggested that LPS/ENR-treated hepatocytes were damaged via apoptotic signaling pathways and CAG prevented LPS/ENR-induced hepatocyte injury.

Pecan pericarp extract protects against carbon tetrachloride-induced liver injury through oxidative mechanism in rats

The purpose of this study was to quantify the proanthocyanidin content of pecan (Carya illinoinensis) pericarp extract (PPE) and to assess its useful impacts against carbon tetrachloride (CCl4)-induced hepatotoxicity. Rats were randomly divided into four groups: Group 1: received intraperitoneal injection of saline solution, Group 2: was injected with PPE (25 mg/kg body weight) for 10 consecutive days, Group 3: received CCl4 (0.5 ml/kg, subcutaneous injection), Group 4: was coadministred with PPE + CCl4. The CCl4 was administered every 3 days during 10 days. Results revealed the presence of a high amount of total proanthocyanidins in the PPE (81.01 ± 0.21 mg TAE.g-1DW). CCl4 injection induced significant reductions in hepatic antioxidants but increased hepatic lipid peroxidation (LPO) as well as serum injury biomarkers. However, cotreatment with PPE significantly (P < 0.05) inverted CCl4-induced increase in plasma alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase activities, respectively to 74%, 77%, 60%, and 82% compared with CCl4 group. No significant toxic effects were observed following treatment with plant extract alone. PPE cotreatment also decreased significant (P < 0.05) the hepatic malondialdehyde formation (21%) and enhanced the liver catalase activity (107%) in CCl4-intoxicated rats. The histopathological examination showed inflammatory infiltration and degenerative changes in the hepatic tissue following CCl4 injection. The hepatoprotective activity of PPE against CCl4 exposure was supported by the maintenance of structural integrity of liver histopathology. In conclusion, the current study illustrated that PPE pretreatment significantly improved all examined parameters, restored the hepatic architecture and successfully alleviates oxidative damage induced by CCl4 intoxication.

Tribulus terrestris ameliorates carbon tetrachloride-induced hepatotoxicity in male rats through suppression of oxidative stress and inflammation

Hepatoprotection is a goal for the harmful effect of several hepatotoxic agents. The present study has been executed to assess the useful impacts of Tribulus terrestris (TT) and silymarin (SLM) against carbon tetrachloride (CCL₄)-induced hepatotoxicity. Forty-two male rats were partitioned into six groups: group I: received 0.3% CMC-Na in distilled water, group II: TT (500 mg/kg BW, orally), group III: SLM (200 mg/kg, orally) for 14 consecutive days (on days 11 and 12 intraperitoneal corn oil), group IV: CCL₄, group V: TT (500 mg/kg BW) plus CCL₄, and group VI: SLM (200 mg/kg orally) plus CCL₄. The CCL₄ was administered (2.0 ml/kg BW) intraperitoneal on days 11 and 12. Sera were collected for assessment of hepatic injury markers and pro-inflammatory cytokines. Additionally, liver tissue oxidative stress, lipid peroxidation, histopathological examination, and immunohistochemical analysis (Bax and bcl-2) were done. CCL₄ injection induced significant reductions in hepatic antioxidants while increased hepatic lipid peroxidation as well as serum hepatic injury biomarkers and pro-inflammatory cytokines. The histopathological examination showed necrotic and degenerative changes in the hepatic tissue, while immunohistochemical analysis revealed marked hepatic expression of activated Bax, and bcl-2, following CCL₄ injection. TT pretreatment significantly improved all examined parameters and restored the hepatic architecture. The current study illustrated that TT effectively alleviates hepatic oxidative damage, apoptosis, and inflammation, induced by acute CCL₄ intoxication. In this manner, TT has promising cytoprotective powers against hepatotoxicity induced by CCL₄.

Possible Pathways of Hepatotoxicity Caused by Chemical Agents

BACKGROUND

Liver injury induced by drugs has become a primary reason for acute liver disease and therefore posed a potential regulatory and clinical challenge over the past few decades and has gained much attention. It also remains the most common cause of failure of drugs during clinical trials. In 50% of all acute liver failure cases, drug-induced hepatoxicity is the primary factor and 5% of all hospital admissions.

METHODS

The various hepatotoxins used to induce hepatotoxicity in experimental animals include paracetamol, CCl4, isoniazid, thioacetamide, erythromycin, diclofenac, alcohol, etc. Among the various models used to induce hepatotoxicity in rats, every hepatotoxin causes toxicity by different mechanisms.

RESULTS

The drug-induced hepatotoxicity caused by paracetamol accounts for 39% of the cases and 13% hepatotoxicity is triggered by other hepatotoxic inducing agents.

CONCLUSION

Research carried out and the published papers revealed that hepatotoxins such as paracetamol and carbon- tetrachloride are widely used for experimental induction of hepatotoxicity in rats.

Drug-Induced Liver Injury in GI Practice

Although drug-induced liver injury (DILI) is a rare clinical event, it carries significant morbidity and mortality, leaving it as the leading cause of acute liver failure in the United States. It is one of the most challenging diagnoses encountered by gastroenterologists. The development of various drug injury networks has played a vital role in expanding our knowledge regarding drug-related and herbal and dietary supplement-related liver injury. In this review, we discuss what defines liver injury, epidemiology of DILI, its biochemical and pathologic patterns, and management.

Pharmacological Effects and Toxicogenetic Impacts of Omeprazole: Genomic Instability and Cancer

Omeprazole (OME) is commonly used to treat gastrointestinal disorders. However, long-term use of OME can increase the risk of gastric cancer. We aimed to characterize the pharmacological effects of OME and to correlate its adverse effects and toxicogenetic risks to the genomic instability mechanisms and cancer-based on database reports. Thus, a search (till Aug 2019) was made in the PubMed, Scopus, and ScienceDirect with relevant keywords. Based on the study objective, we included 80 clinical reports, forty-six in vitro, and 76 in vivo studies. While controversial, the findings suggest that long-term use of OME (5 to 40 mg/kg) can induce genomic instability. On the other hand, OME-mediated protective effects are well reported and related to proton pump blockade and anti-inflammatory activity through an increase in gastric flow, anti-inflammatory markers (COX-2 and interleukins) and antiapoptotic markers (caspases and BCL-2), glycoprotein expression, and neutrophil infiltration reduction. The reported adverse and toxic effects, especially in clinical studies, were atrophic gastritis, cobalamin deficiencies, homeostasis disorders, polyp development, hepatotoxicity, cytotoxicity, and genotoxicity. This study highlights that OME may induce genomic instability and increase the risk of certain types of cancer. Therefore, adequate precautions should be taken, especially in its long-term therapeutic strategies and self-medication practices.

Enhanced cytotoxicity of imidacloprid by biotransformation in isolated hepatocytes and perfused rat liver

Imidacloprid (IMD) is a neonicotinoid insecticide widely used in crops, pets, and on farm animals for pest control, which can cause hepatotoxicity in animals and humans. In a previous study using isolated rat liver mitochondria, we observed that IMD inhibited the activity of F_oF₁-ATP synthase. The aim of this study was to evaluate the effects of IMD on rat isolated hepatocytes and perfused rat liver, besides the influence of its biotransformation on the toxicological potential. For the latter goal, rats were pretreated with dexamethasone or phenobarbital, two classical cytochrome P-450 stimulators, before hepatocytes isolation or liver perfusion. IMD (150 and 200 μM) reduced state 3 mitochondrial respiration in digitonin-permeabilized cells that were energized with glutamate plus malate but did not dissipate the mitochondrial membrane potential. In intact (non-permeabilized) hepatocytes, the intracellular ATP concentration and cell viability were reduced when high IMD concentrations were used (1.5-3.0 mM), and only in cells isolated from dexamethasone-pretreated rats, revealing that IMD biotransformation increases its toxicity and that IMD itself affects isolated mitochondria or mitochondria in permeabilized hepatocytes in concentrations that do not affect mitochondrial function in intact hepatocytes. Coherently, in the prefused liver, IMD (150 and 250 μM) inhibited gluconeogenesis from alanine, but without affecting oxygen consumption and urea production, indicating that such effect was not of mitochondrial origin. The gluconeogenesis inhibition was incomplete and occurred only when the rats were pretreated with phenobarbital, signs that IMD biotransformation was involved in the observed effect. Our findings reveal that changes in hepatic energy metabolism may be acutely implicated in the hepatotoxicity of IMD only when animals and humans are exposed to high levels of this compound, and that IMD metabolites seem to be the main cause for its toxicity.

Apigenin alleviated acetaminophen-induced hepatotoxicity in low protein-fed rats: Targeting oxidative stress, STAT3, and apoptosis signals

Apigenin (API) is a natural flavonoid abundant in fruits and vegetables. The present study was undertaken to evaluate the effect of protein malnutrition (PMN) on acetaminophen (APAP)-induced hepatotoxicity, together with the protective effects of API, in male Wistar albino rats. In total, 64 male rats were divided into eight groups. Silymarin (SIL) (100 mg/kg, PO) as a reference standard and API (50 mg/kg, PO) were given to normal and APAP-induced hepatic injury in low protein-fed rats. The present results revealed that PMN significantly potentiated APAP-induced hepatotoxicity. Interestingly, the administration of SIL and API alleviated the induced damage, as revealed by reduced serum alanine aminotransferase and aspartate aminotransferase activities along with a significant improvement of the histopathological damage. API suppressed inflammatory response by reducing the interleukin-1β level and signal transducer and activator of transcription 3 expressions along with attenuating oxidative stress as shown by a significant reduction in liver contents of malondialdehyde and nitrite/nitrate as well as restoration of hepatic content of reduced glutathione and superoxide dismutase activity. API also counteracted apoptosis through downregulation of caspase-3 expression level. In conclusion, PMN greatly potentiated the hepatotoxic effects of APAP, and API produced a multimechanistic hepatoprotective activity that can be attributed to its antioxidant, anti-inflammatory, and antiapoptotic effects.

HEPATOPROTECTIVE EFFICACY OF METHANOLIC EXTRACT OF INDIGOFERA SUFFRUTICOSA (MILL) ON PARACETAMOL-INDUCED LIVER DAMAGE IN MICE

BACKGROUND

Indigofera suffruticosa Mill (Fabaceae) is abundant in northeastern Brazil and popularly used in the treatment of infectious and inflammatory processes. Several biological properties, such as anti-inflammatory, anticancer, antitumor, hepatoprotective and low toxicity, are reported for this plant.

OBJECTIVE

This study investigated hepatoprotective activity and the antioxidant effect of methanolic extract of I. suffruticosa leaves (MEIS) on Swiss albino mice submitted to experimental models of acetaminophen-induced liver injury.

METHODS

MEIS (50 mg/kg; p.o.) was standardized according to the LD50 and its hepatoprotective property on Swiss albino mice evaluated during a 7-day period. On the eighth day, the acetaminophen-induced hepatic injury was performed. Histomorphometric analysis of liver tissue, antioxidant activity and serum levels of alanine aminotransferase (AST), aspartate aminotransferase (ALT) and bilirubin were measured.

RESULTS

MEIS (50 mg/kg; p.o.) restored serum enzyme levels and results were close to those of positive control (silymarin) when compared to the negative control. Histopathological and histomorphometric analyzes confirmed MEIS hepatoprotective activity, showing reorganization of structural units of cells, nuclei and sinusoidal capillaries of hepatocytes, reducing the damage on liver tissue and increasing organ regeneration rate. MEIS showed high antioxidant potential at concentrations of 1000 and 500 µg/mL.

CONCLUSION

This study suggests that MEIS has hepatoprotective activity and high antioxidant potential.

Liver enzyme elevation in patients taking HAART compared with treatment naïve controls at Debre Berhan Referral Hospital: a comparative cross-sectional study, Northeast Ethiopia

Objective

HAART had significantly improved the quality of life of HIV patients. However, it results different adverse effects such as: hepatotoxicity, nephrotoxicity, lipodystrophy, anemia, diarrhea, psychiatric disorder and others. Therefore, this comparative cross sectional study was designed to investigate liver enzyme elevation in patients taking HAART compared with treatment naïve controls at Debre Berhan Referral Hospital.

Result

A total of 152 individuals (76 cases and 76 controls) were included in this study. The mean ages of treatment and control groups were 37.37 and 36.38 respectively. The mean values of liver enzymes (ALT, AST and ALP), total bilirubin and direct bilirubin were significantly higher (p < 0.05) while, total protein and creatinine were significantly lower in patients taking HAART compared with treatment naïve controls. In this study, about 19 (25%) of clients in HAART treated groups and 7 (9.2%) of treatment naïve controls had showed liver enzyme changes. Moreover, 23.7% and 1.3% of the HAART treated groups developed mild and moderate liver enzyme elevation or hepatotoxicity, respectively. In this study, significant difference was observed in liver enzyme elevation between ART and pre-ART patients. As a result, regular clinical and laboratory monitoring of liver function will be necessary to prevent severe form of liver injury.

Elevated circulating TGFβ1 during acute liver failure activates TGFβR2 on cortical neurons and exacerbates neuroinflammation and hepatic encephalopathy in mice

BACKGROUND

Acute liver failure resulting from drug-induced liver injury can lead to the development of neurological complications called hepatic encephalopathy (HE). Hepatic transforming growth factor beta 1 (TGFβ1) is upregulated due to liver failure in mice and inhibiting circulating TGFβ reduced HE progression. However, the specific contributions of TGFβ1 on brain cell populations and neuroinflammation during HE are not known. Therefore, the aim of this study was to characterize hepatic and brain TGFβ1 signaling during acute liver failure and its contribution to HE progression using a combination of pharmacological and genetic approaches.

METHODS

C57Bl/6 or neuron-specific transforming growth factor beta receptor 2 (TGFβR2) null mice (TGFβR2^ΔNeu) were treated with azoxymethane (AOM) to induce acute liver failure and HE. The activity of circulating TGFβ1 was inhibited in C57Bl/6 mice via injection of a neutralizing antibody against TGFβ1 (anti-TGFβ1) prior to AOM injection. In all mouse treatment groups, liver damage, neuroinflammation, and neurological deficits were assessed. Inflammatory signaling between neurons and microglia were investigated in in vitro studies through the use of pharmacological inhibitors of TGFβ1 signaling in HT-22 and EOC-20 cells.

RESULTS

TGFβ1 was expressed and upregulated in the liver following AOM injection. Pharmacological inhibition of TGFβ1 after AOM injection attenuated neurological decline, microglia activation, and neuroinflammation with no significant changes in liver damage. TGFβR2^ΔNeu mice administered AOM showed no effect on liver pathology but significantly reduced neurological decline compared to control mice. Microglia activation and neuroinflammation were attenuated in mice with pharmacological inhibition of TGFβ1 or in TGFβR2^ΔNeu mice. TGFβ1 increased chemokine ligand 2 (CCL2) and decreased C-X3-C motif ligand 1 (CX3CL1) expression in HT-22 cells and reduced interleukin-1 beta (IL-1ß) expression, tumor necrosis factor alpha (TNFα) expression, and phagocytosis activity in EOC-20 cells.

CONCLUSION

Increased circulating TGFβ1 following acute liver failure results in activation of neuronal TGFβR2 signaling, driving neuroinflammation and neurological decline during AOM-induced HE.

Involvement of diclofenac acyl-β-d-glucuronide in diclofenac-induced cytotoxicity in glutathione-depleted isolated murine hepatocytes co-cultured with peritoneal macrophages

Direct hepatotoxic effects of drugs can occur when a parent drug and/or its reactive metabolites induces the formation of reactive oxygen species. Reactive metabolites of diclofenac (DIC) such as DIC acyl-β-d-glucuronide (DIC-AG) bind covalently to proteins, potentially decreasing protein function or inducing an immune response. However, it is unclear whether the macrophages and GSH depletion participate in DIC-induced cytotoxicity. Mouse hepatocytes (Hep) co-cultured with peritoneal macrophages (PMs) were used to clarify the effects of presence of PM with GSH depletion on DIC-induced cytotoxicity in Hep. DIC-AG but not hydroxy-DIC concentrations in medium were significantly increased in Hep co-cultured with PM with GSH depletion. Depletion of GSH resulted in significantly higher LDH leakage. Interestingly, LDH leakage in Hep/PM (1:0.4) with GSH depletion was significantly higher than in Hep/PM (1:0 and 1:0.1) with BSO. It is likely that macrophages with GSH depletion could facilitate DIC-induced cytotoxicity.

Evaluation of multikinase inhibitor LDN193189 induced hepatotoxicity in teleost fish Poecilia latipinna

Currently, scientists show keen interest in the drugs that inhibit multiple kinases, LDN193189, being an example. It combats certain cancers in vitro as well as in vivo, making it a prerequisite for researchers to study the toxic potential of this drug in animal models. As most of the drugs metabolized by liver cause hepatic injury, LDN193189-induced hepatotoxicity was examined using a teleost fish, Poecilia latipinna. As a prelude, calculation of LD₅₀ showed a value of 95.22 mg/kg body weight and three doses were decided based on it for further evaluations. All these groups were tested for antioxidant enzyme levels and were significantly raised for mid- and high-dose group. Similar trend was recorded for ALP, AST, and ALT levels. Furthermore, some key indicators of drug metabolism in liver were tested for their expression in response to LDN193189 treatment. Among these, Cyt-C, CYP3A4, CYP1B1 and CYP1A1 were elevated in mid- and high dose, except CYP21A1, which declined remarkably. Moreover, histological profile of the liver reflected high degree of inflammation due to drug treatment, but this was found only at high dose. In summary, LDN193189, at 2.5 mg/kg body weight, did not cause any adverse hepatotoxicity, rendering it safe for use as an anti-proliferative agent - an activity for which it has already shown promising results in the same animal model. The low-dose group previously studied for its anti-proliferative property showed no adverse effect in liver, whereas the mid- and high dose induced moderate or severe hepatotoxicity in P. latipinna.

Silymarin and caffeine combination ameliorates experimentally-induced hepatic fibrosis through down-regulation of LPAR1 expression

AIMS

Lysophosphatidic acid is a lipid mediator that is supposed to be implicated in hepatic fibrosis. Silymarin and caffeine are natural compounds known for their anti-inflammatory and antioxidant effects. Our study aimed to explore the effect of silymarin, caffeine, and their combination on lysophosphatidic acid receptor 1 (LPAR1) pathway in thioacetamide (TAA)-induced hepatic fibrosis.

MAIN METHODS

Hepatic fibrosis was induced in male Sprague-Dawley rats by intraperitoneal injection of 200 mg/kg of TAA twice a week for 8 weeks. Silymarin (50 mg/kg), caffeine (50 mg/kg), and their combination (50 mg/kg silymarin + 50 mg/kg caffeine) were orally given to rats every day for 8 weeks along with TAA injection. Liver functions were measured. Histopathological examination of liver tissues was performed using hematoxylin and eosin and Masson's trichrome staining. mRNA expressions of LPAR1, transforming growth factor beta 1 (TGF-β1), connective tissue growth factor (CTGF), and alpha smooth muscle actin (α-SMA) were measured using RT-PCR. LPAR1 tissue expression was scored using immunohistochemistry.

KEY FINDINGS

Silymarin, caffeine, and their combination significantly improved liver function. They caused significant decrease in fibrosis and necro-inflammatory scores. Combination of silymain and caffeine caused a significant decrease in the necro-inflammatory score than the single treatment with silymarin or caffeine. In addition, silymarin, caffeine, and their combination significantly decreased hepatic LPAR1, TGF-β1, CTGF, and α-SMA gene expressions and LPAR1 tissue expression.

SIGNIFICANCE

Silymarin, caffeine, and their combination protect against liver fibrosis through down-regulation of LPAR1, TGF-β1, and CTGF.

Safety data and withdrawal of hepatotoxic drugs

BACKGROUND AND AIM

The occurrence of drug induced liver injury (DILI) is the most common reason of post-marketing withdrawals. DILI in humans is difficult to predict using in vitro cytotoxicity screening and animal studies. A review of hepatotoxicity data was performed with the aim of identifying relevant factors that could have predicted the occurrence of serious DILI.

METHODS

The drugs withdrawn from the market due to hepatotoxicity in Europe and/or in USA either by marketing authorization holders or by Regulatory agencies from 1997 to 2016 were selected. The liver safety data and the withdrawal decisions were identified from a search within the European medicine agency (EMA) website, the Food and drug administration (FDA) orange book and PubMed^®.

RESULTS

From 1997 to 2016, eight drugs were withdrawn from the market for hepatotoxicity reason: tolcapone, troglitazone, trovafloxacin, bromfenac, nefazodone, ximelagatran, lumiracoxib and sitaxentan. The safety data suggest that while liver test abnormalities have been detected during clinical trials, other relevant factors leading to the discontinuation of these drugs have been identified: lack of predictability of animal models, inappropriate liver function test, non-compliance with drug treatment, less attention paid to rare adverse drug reactions, unpredictable occurrence and irreversible outcome of liver toxicity.

CONCLUSION

Several relevant factors may contribute to an inadequate risk management leading to the discontinuation of the drugs. Preclinical safety data are not sufficient to allow early prediction of DILI in humans and post-marketing safety monitoring and signal detection still should be used to identify potential serious cases of DILI. However, it seems that changes in Pharmacovigilance legislation with a closer management of drug safety may have contributed to the improvement of the risk minimization.

Next generation of network medicine: interdisciplinary signaling approaches

In the last decade, network approaches have transformed our understanding of biological systems. Network analyses and visualizations have allowed us to identify essential molecules and modules in biological systems, and improved our understanding of how changes in cellular processes can lead to complex diseases, such as cancer, infectious and neurodegenerative diseases. "Network medicine" involves unbiased large-scale network-based analyses of diverse data describing interactions between genes, diseases, phenotypes, drug targets, drug transport, drug side-effects, disease trajectories and more. In terms of drug discovery, network medicine exploits our understanding of the network connectivity and signaling system dynamics to help identify optimal, often novel, drug targets. Contrary to initial expectations, however, network approaches have not yet delivered a revolution in molecular medicine. In this review, we propose that a key reason for the limited impact, so far, of network medicine is a lack of quantitative multi-disciplinary studies involving scientists from different backgrounds. To support this argument, we present existing approaches from structural biology, 'omics' technologies (e.g., genomics, proteomics, lipidomics) and computational modeling that point towards how multi-disciplinary efforts allow for important new insights. We also highlight some breakthrough studies as examples of the potential of these approaches, and suggest ways to make greater use of the power of interdisciplinarity. This review reflects discussions held at an interdisciplinary signaling workshop which facilitated knowledge exchange from experts from several different fields, including in silico modelers, computational biologists, biochemists, geneticists, molecular and cell biologists as well as cancer biologists and pharmacologists.

Drug-Induced Liver Injury in Children: Clinical Observations, Animal Models, and Regulatory Status

Drug-induced liver injury in children (cDILI) accounts for about 1% of all reported adverse drug reactions throughout all age groups, less than 10% of all clinical DILI cases, and around 20% of all acute liver failure cases in children. The overall DILI susceptibility in children has been assumed to be lower than in adults. Nevertheless, controversial evidence is emerging about children's sensitivity to DILI, with children's relative susceptibility to DILI appearing to be highly drug-specific. The culprit drugs in cDILI are similar but not identical to DILI in adults (aDILI). This is demonstrated by recent findings that a drug frequently associated with aDILI (amoxicillin/clavulanate) was rarely associated with cDILI and that the drug basiliximab caused only cDILI but not aDILI. The fatality in reported cDILI studies ranged from 4% to 31%. According to the US Food and Drug Administration-approved drugs labels, valproic acid, dactinomycin, and ampicillin appear more likely to cause cDILI. In contrast, deferasirox, isoniazid, dantrolene, and levofloxacin appear more likely to cause aDILI. Animal models have been explored to mimic children's increased susceptibility to valproic acid hepatotoxicity or decreased susceptibility to acetaminophen or halothane hepatotoxicity. However, for most drugs, animal models are not readily available, and the underlying mechanisms for the differential reactions to DILI between children and adults remain highly hypothetical. Diagnosis tools for cDILI are not yet available. A critical need exists to fill the knowledge gaps in cDILI. This review article provides an overview of cDILI and specific drugs associated with cDILI.

Azithromycin-induced cholestatic hepatitis

Since its introduction >20 years ago, Azithromycin has been widely used owing to its broad spectrum and good tolerability, especially when used for <7 days. In literature, there are only very few, sporadic reports available of patients developing cholestatic hepatitis following treatment with it. The current case study describes a 69-year old patient, with a medical history that included significant alcohol consumption, who presented with jaundice following a 3-day course of Azithromycin. Following a transjugular liver biopsy, he was managed with a short course of corticosteroids and his liver function gradually improved and finally normalized ~2 months after discontinuation of Azithromycin.

Nonionic surfactant based thymoquinone loaded nanoproniosomal formulation: in vitro physicochemical evaluation and in vivo hepatoprotective efficacy

CONTEXT

The present study was carried out to formulate thymoquinone proniosomal formulation (TQP) and evaluate their efficacy in methotrexate (Mtx) induced hepatotoxicity in rats.

OBJECTIVE

The objective of the study was to explore a new therapeutic approach focusing on hepatoprotective activity using thymoquinone proniosomal formulation.

MATERIAL AND METHODS

TQP was formulated using span60, cholesterol and phospholipid by film hydration technique. The animals were divided into six groups with five animals each receiving different treatments for 7 days. On the 8th day, rats were anesthetized with ether, blood samples were withdrawn, livers were dissected out for biochemical tests and histopathological examinations.

RESULTS AND DISCUSSION

The size of vesicle was found to be in the nanometric range with higher entrapment efficiency. The high entrapment efficiency is probably due to the lipophilic character of TQ. The morphological structure showed the outline and core of the well-identified spherical vesicle, and also displaying the retention of sealed vesicular structure. The release of TQ from developed formulation was found to be significantly higher compared to control. Mtx treated rats showed significant elevation in ALT, AST, ALP and TBARs, whereas, TQP treated group showed significant reduction.

CONCLUSION

The developed formulation (TQP) significantly inhibited the elevated levels of serum marker enzymes and showed improved histopathological deformities.

Involvement of Reactive Metabolites of Diclofenac in Cytotoxicity in Sandwich-Cultured Rat Hepatocytes

Background and Objectives:

Diclofenac (DIC) is metabolized to reactive metabolites such as diclofenac acyl-β-d-glucuronide (DIC-AG). It is possible that such reactive metabolites could cause tissue damage by formation of covalent protein adducts and other modification of cellular proteins or by induction of immune responses against its covalent protein adducts. However, the detailed mechanisms of idiosyncratic drug-induced liver injury (DILI) have been unclear. The objective is to clarify the involvement of DIC-AG and 4′hydroxydiclofenac (4′OH-DIC) in acute DILI.

Methods:

We examined the effects of inhibiting DIC-AG and 4′OH-DIC production on covalent protein adduct formation and lactate dehydrogenase leakage using sandwich-cultured rat hepatocytes (SCRHs).

Results:

After pretreatment of SCRH with (−)-borneol (BOR, a uridine diphosphate (UDP)-glucuronosyltransferase inhibitor) or sulfaphenazole (SUL, a cytochrome P450 2C9 inhibitor) for 30 minutes, intracellular concentrations of DIC, DIC-AG, and 4′OH-DIC were determined after further treating cells with 300 μM DIC for 3 hours. The decreased levels of reactive metabolites caused by BOR or SUL pretreatment resulted in decreased lactate dehydrogenase leakage from SCRH, although the formation of covalent protein adducts was not affected.

Conclusion:

These results suggested that both DIC-AG and 4′OH-DIC may be involved in acute cytotoxicity by DIC.

Identification of novel MRP3 inhibitors based on computational models and validation using an in vitro membrane vesicle assay

INTRODUCTION

Multidrug resistance-associated protein 3 (MRP3), an efflux transporter on the hepatic basolateral membrane, may function as a compensatory mechanism to prevent the accumulation of anionic substrates (e.g., bile acids) in hepatocytes. Inhibition of MRP3 may disrupt bile acid homeostasis and is one hypothesized risk factor for the development of drug-induced liver injury (DILI). Therefore, identifying potential MRP3 inhibitors could help mitigate the occurrence of DILI.

METHODS

Bayesian models were developed using MRP3 transporter inhibition data for 86 structurally diverse drugs. The compounds were split into training and test sets of 57 and 29 compounds, respectively, and six models were generated based on distinct inhibition thresholds and molecular fingerprint methods. The six Bayesian models were validated against the test set and the model with the highest accuracy was utilized for a virtual screen of 1470 FDA-approved drugs from DrugBank. Compounds that were predicted to be inhibitors were selected for in vitro validation. The ability of these compounds to inhibit MRP3 transport at a concentration of 100μM was measured in membrane vesicles derived from stably transfected MRP3-over-expressing HEK-293 cells with [³H]-estradiol-17β-d-glucuronide (E₂17G; 10μM; 5min uptake) as the probe substrate.

RESULTS

A predictive Bayesian model was developed with a sensitivity of 73% and specificity of 71% against the test set used to evaluate the six models. The area under the Receiver Operating Characteristic (ROC) curve was 0.710 against the test set. The final selected model was based on compounds that inhibited substrate transport by at least 50% compared to the negative control, and functional-class fingerprints (FCFP) with a circular diameter of six atoms, in addition to one-dimensional physicochemical properties. The in vitro screening of predicted inhibitors and non-inhibitors resulted in similar model performance with a sensitivity of 64% and specificity of 70%. The strongest inhibitors of MRP3-mediated E₂17G transport were fidaxomicin, suramin, and dronedarone. Kinetic assessment revealed that fidaxomicin was the most potent of these inhibitors (IC₅₀=1.83±0.46μM). Suramin and dronedarone exhibited IC₅₀ values of 3.33±0.41 and 47.44±4.41μM, respectively.

CONCLUSION

Bayesian models are a useful screening approach to identify potential inhibitors of transport proteins. Novel MRP3 inhibitors were identified by virtual screening using the selected Bayesian model, and MRP3 inhibition was confirmed by an in vitro transporter inhibition assay. Information generated using this modeling approach may be valuable in predicting the potential for DILI and/or MRP3-mediated drug-drug interactions.

A case of probable esomeprazole-induced transient liver injury in a pregnant woman with hyperemesis

We report a case of 22-year-old primigravida presented to Women’s Hospital – Hamad Medical Corporation emergency with severe epigastric pain, nausea, and vomiting. On admission, she was dehydrated with remarkably worsening symptoms. Laboratory findings revealed significantly elevated liver enzymes with unknown etiology. Her past medical history showed an admission for nausea and vomiting 3 weeks previously and she was discharged on antiemetics, and esomeprazole for the first time. Due to the predominantly elevated liver enzymes, the clinical pharmacist discussed the possibility of esomeprazole-induced adverse effects and suggested to suspend esomeprazole based on the evidence from literature review. The liver enzymes showed a substantial improvement within days after the discontinuation of the drug; however, a rechallenge was not done since it could have adversely affected the mother or the fetus. Using the Naranjo Adverse Drug Reaction Probability scales, the adverse reaction due to esomeprazole was classified as “probably”.

Safety Assessment of Liver Injury with Quetiapine Fumarate XR Management in Very Heavy Drinking Alcohol-Dependent Patients

BACKGROUND

Studies have reported liver injury as a consequence of antipsychotic treatment. Very heavy alcohol drinking (ten or more drinks/day for men and eight for women) also causes liver injury. This study aims to evaluate liver injury with quetiapine extended release (XR) in very heavy drinking alcohol-dependent (AD) patients.

METHODS

Two hundred and eighteen AD patients, 18-65 years of age, received 12 weeks of quetiapine XR or placebo treatment in a dose-escalated manner reaching the full dose of 400 mg/day during week 4. Blood chemistry and hematology were assessed at baseline (W0), post-titration at the end of week 3 (W4), week 8 (W8), and end of week 12 (W13). Patients were further grouped as GR.1 (no liver injury, ALT ≤40) and GR.2 (pre-existing liver injury, ALT >40) within each treatment. Drinking history, fasting blood glucose concentration (FBG), and lipid panel were used as covariates in the analyses.

RESULTS

Liver injury and total drinks and average drinking measures from the Timeline follow-back questionnaire (TLFB) were highly associated. No significant exacerbation in liver injury was observed in patients treated with quetiapine XR in GR.2. Liver injury as determined by elevated alanine aminotransaminase (ALT) was reported in a few patients in GR.1 who received quetiapine XR; however, the occurrence was low, and the level of liver injury was not significant. FBG and lipid measures showed some elevation, but did not show any significant association with liver injury.

CONCLUSION

Quetiapine XR did not show any significant exacerbation of liver injury in very heavy drinking alcohol-dependent patients with pre-existing liver injury. Frequency and severity of new liver injury cases in quetiapine XR-treated patients without any pre-existing liver injury was also low. Study findings support medical management of AD patients with heavy drinking profile using quetiapine XR formulation.

Epigallocatechin-3-gallate Prevents Triptolide-Induced Hepatic Injury by Restoring the Th17/Treg Balance in Mice

Drug-induced liver injury (DILI) is the most common cause of acute liver failure. Disruption of the Th17/Treg balance can lead to hepatic inflammation, which causes the main symptoms of DILI. Here we investigate the protective mechanisms of (-)-Epigallocatechin-3-gallate (EGCG) on triptolide (TP)-induced DILI that shows the Th17/Treg imbalance. Pretreatment with EGCG (5[Formula: see text]mg/kg) for 10 days before TP (0.5[Formula: see text]mg/kg) administration in mice significantly reduced the increased alanine aminotransferase (ALT) level ([Formula: see text]) induced by TP treatment. The hepatic histology analysis further proved that EGCG protected mice from TP-induced liver injury. The imbalance of Th17/Treg was induced by TP treatment, as shown by the upregulation of TLR4 and downregulation of Tim3 expression. EGCG pretreatment can maintain the expression of TLR4 and Tim3 at normal levels to restore the Th17/Treg imbalance. In addition, EGCG can block the TP-induced expression of the downstream targets of TLR4, including MyD88, NF[Formula: see text]B, and retinoid related orphan receptor (ROR-[Formula: see text]t), while EGCG can restore the TP inhibition of forkhead/winged-helix family transcriptional repressor p3 (FoxP3) that is the downstream target of Tim3. Consequently, EGCG pretreatment can effectively inhibit the Th17-related pro-inflammatory cytokine (e.g. IL-17 and IL-6) upregulation induced by TP treatment. However, TP inhibition of Treg-related anti-inflammatory cytokine IL-10 production was restored by EGCG pretreatment. Taken together, these results suggest that EGCG possesses significant protective properties against TP-induced hepatic inflammatory injury, and that these properties are carried out via the restoration of the Th17/Treg imbalance by the inhibition of the TLR4 signaling pathway and the enhanced activation of the Tim3 signaling pathway.

Acute and Fatal Isoniazid-Induced Hepatotoxicity: A Case Report and Review of the Literature

This paper describes a case of an acute and fatal isoniazid-induced hepatotoxicity and provides a review of the literature. A 65-year-old female diagnosed with latent Mycobacterium tuberculosis infection was receiving oral isoniazid 300 mg daily. She was admitted to the hospital for epigastric and right sided flank pain of one-week duration. Laboratory results and imaging confirmed hepatitis. After ruling out all other possible causes, she was diagnosed with isoniazid-induced acute hepatitis (probable association by the Naranjo scale). After discharge, the patient was readmitted and suffered from severe coagulopathy, metabolic acidosis, acute kidney injury, hepatic encephalopathy, and cardiorespiratory arrest necessitating two rounds of cardiopulmonary resuscitation. Despite maximal hemodynamic support, the patient did not survive. A review of the literature, from several European countries and the United States of America, revealed a low incidence of mortality due to isoniazid-induced hepatotoxicity when used as a single agent for latent Mycobacterium tuberculosis infection. As for the management, the first step consists of withdrawing isoniazid and rechallenge is usually discouraged. Few treatment modalities have been proposed; however there is no robust evidence to support any of them. Routine monitoring for hepatotoxicity in patients receiving isoniazid is warranted to prevent morbidity and mortality.

Expression of miRNA-122 Induced by Liver Toxicants in Zebrafish

MicroRNA-122 (miRNA-122), also known as liver-specific miRNA, has recently been shown to be a potent biomarker in response to liver injury in mammals. The objective of this study was to examine its expression in response to toxicant treatment and acute liver damage, using the zebrafish system as an alternative model organism. For the hepatotoxicity assay, larval zebrafish were arrayed in 24-well plates. Adult zebrafish were also tested and arrayed in 200 mL cages. Animals were exposed to liver toxicants (tamoxifen or acetaminophen) at various doses, and miRNA-122 expression levels were analyzed using qRT-PCR in dissected liver, brain, heart, and intestine, separately. Our results showed no significant changes in miRNA-122 expression level in tamoxifen-treated larvae; however, miRNA-122 expression was highly induced in tamoxifen-treated adults in a tissue-specific manner. In addition, we observed a histological change in adult liver (0.5 μM) and cell death in larval liver (5 μM) at different doses of tamoxifen. These results indicated that miRNA-122 may be utilized as a liver-specific biomarker for acute liver toxicity in zebrafish.

Exploring an animal model of amodiaquine-induced liver injury in rats and mice

Amodiaquine (AQ) is associated with a relatively high incidence of idiosyncratic drug-induced liver injury (IDILI) and agranulocytosis. A previous study reported that a combination of high dose AQ and glutathione (GSH) depletion led to liver injury. However, the characteristics of this toxicity were very different from AQ-induced liver injury in humans. We developed a model of AQ-induced liver injury with characteristics similar to the injury in humans by treating mice with lower doses of AQ for several weeks. In this study we found that not only did GSH depletion not increase AQ covalent binding to hepatic proteins at this lower dose, but also it paradoxically prevented the liver injury. We extended the model to rats and found AQ treatment led to a mild delayed onset liver injury that resolved despite continued treatment with AQ. Immunohistochemistry indicated the presence of Kupffer cell activation, apoptosis and hepatocyte proliferation in the liver. There was also an increase in serum IL-2, IL-5, IL-9, IL-12, MCP-1 and TGFβ, but a decrease in leptin. Coincident with the elevated serum ALT, the number of liver CD4(+) T-cells, IL-17 secreting cells and TH17/Treg cells increased at Week 3 and decreased during continued treatment. Increases in NK1.1+ cells and activated M2 macrophages were also observed during liver injury. These results suggest that the outcome of the liver injury was determined by the balance between effector and regulatory cells. Co-treatment with cyclosporin prevented AQ-induced liver injury, which supports an immune mechanism. Retinoic acid (RA), which has been reported to enhance natural killer (NK) cell activity, exacerbated AQ-induced liver injury. These results suggest that AQ-induced IDILI is immune mediated and the subsequent adaptation appears to represent immune tolerance.