The potential of cytokines as safety biomarkers for drug-induced liver injury

Comparison of liver injury and inflammatory response following conventional and drug-eluting bead transcatheter chemoembolization in hepatocellular carcinoma

OBJECTIVE

This study aimed to compare the extent of liver injury and the inflammatory response in patients with hepatocellular carcinoma (HCC) following conventional transarterial chemoembolization (cTACE) and drug-eluting bead transarterial chemoembolization (DEB-TACE).

METHODS

Clinical data from October 2018 to October 2019 were prospectively collected to establish a database. The baseline clinical and demographic characteristics of patients in the two groups were matched using propensity score matching (PSM). Serum levels of hepatic function indicators and inflammatory cytokines were evaluated before treatment and five days post-treatment.

RESULTS

A total of 134 participants were included in the analysis. Following 1:1 PSM, 43 patients remained in each group, with no significant differences observed in baseline characteristics. The median absolute concentration of aspartate aminotransferase (AST) was significantly lower in the DEB-TACE group five days after treatment. Among 18 patients who experienced idiosyncratic drug-induced liver injury, the DEB-TACE group exhibited a significantly lower proportion of cases. The alanine aminotransferase/alkaline phosphatase (ALT/ALP) ratio was notably higher in the cTACE group, while cholestatic-type liver injuries were predominant in the DEB-TACE group. Levels of MCP-1, IL-6, and IL-1β were lower in the DEB-TACE group five days post-treatment. Additionally, MCP-1 levels were significantly correlated with ALT levels and the type of liver injury. Similarly, IL-6 levels showed significant correlations with ALT, AST, and the type of liver injury.

CONCLUSIONS

DEB-TACE was associated with reduced acute liver injury, characterized primarily by cholestatic injury, and a milder inflammatory response compared to cTACE. Post-treatment levels of MCP-1 and IL-6 levels were correlated with aminotransferase levels and the type of liver injury.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR-1800017781. Register URL link: https://www.chictr.org.cn/showproj.html?proj=30041 . Register date: 2018-8-14.

Hepatoprotective effect of Nobiletin against 5-fluorouracil induce hepatotoxicity

5-florouracil is a widely used anticancer/anti-metabolite drug used to treat solid tumor like colon cancer, head and neck, rectum, stomach, pancreas and breast cancer; but, it can cause hepatotoxicity by induction of apoptosis through activation of caspases enzymes and oxidative stress. Nobiletin is a citrus fruit-derived flavonoid that possess significant biological activity, including anticancer, and anti-inflammatory. This study was design to investigate the effects of nobiletin against 5-florouracil-indcued hepatotoxicity in male rats through the measurement of selected -inflammatory, -apoptosis, and -oxidative stress markers. By use male Albino rats weighing 150-250gm around 28 animals; giving them tap water ad libitum and fed commercial pellets; and randomized into four groups (7animals/group) as following arrangement: Group I oral administered only corn oil for rats 1 ml for each kilogram for day by using of oral gavage for rat for 14 days. Group II: oral administered Nobiletin at dose 10 mg for each kilogram for each day (dissolved in corn oil) via oral gavage for 14 days. Group III: oral administered corn oil via oral gavage for 14 days after that single IP injection of 5-FU (150 mg/kg) on the day fourteenth (14). Group VI: Rats oral administered nobiletin dissolved in corn oil daily by oral gavage at a dose 10 mg/kg for each day for 14 days and a single IP injection of (150 mg/kg) 5-florouracil was given on day 14. All groups, seven animals of each group were sacrificed at day fifteenth (15); and, serum was collected to measure inflammatory and anti-inflammatory markers (interlukin-6 and interlukin-10) and liver function tests(ALT, LDH and AST); furthermore, liver tissue samples were collected to measure level of caspase-3, malondialdehyde and reduced form of glutathione, assessment of Hemeoxygenase-1 and NADPH quinone dehydrogenase-1 enzymes. In addition, histopathological study of the liver tissue of rats was perform to detect difference between architecture of liver cells in all rats' groups. The protective effect of Nobiletin noted by decrease in apoptosis of hepatocytes by decreasing of caspase-3 and reduction on free radical through reduce in malondialdehyde level, also increase in Hemeoxygenase-1gene expression. Increase in NADPH quinone dehydrogenase-1 dehydrogenase enzyme. On histopath reduce in congestion and some inflammatory infiltration by using of nobiletin prior to give 5-florouracil.

Cytokine storm modulation using cholecalciferol and low dose gamma radiation in Escherichia coli infected mice

This work investigates the efficiency of cholecalciferol and low dose gamma radiation in modulating cytokine storm through their impact on inflammatory and anti-inflammatory cytokine and protecting against lung and liver injuries. Male Swiss albino mice were exposed to 0.2 Gy gamma radiation/week for four consecutive weeks then injected intraperitoneally (i.p) with a single dose of 8.3 × 106 CFU Escherichia coli/g b.w. then injected i.p. with 1.0 mg/kg cholecalciferol (Vit D3) for 7 days starting 4 h after E. coli injection. The results revealed that Cholecalciferol and low dose gamma radiation caused significant depletion in the severity of E. coli infection (colony forming unit per milliliter), log10 of E. coli, Tumor necrosis factor alpha, Interleukin 6, VEGF, alanine aminotransferase, and aspartate aminotransferase levels and significant elevation in IL-10, IL-4, and HO-1. Immunohistochemical analysis of caspase-3 expression in lung tissue section showed low caspase-3 expression in cholecalciferol and low dose gamma radiation treated group. Histopathological examinations were performed in both lung and liver tissues which also emphasis the biochemical findings. Our results exhibit the importance of cholecalciferol and low dose gamma radiation in improving liver function and providing anti-inflammatory response in diseases causing cytokine storm.

Probiotic bacteria protect against indomethacin-induced gastric ulcers through modulation of oxidative stress, inflammation, and apoptosis

BACKGROUND

Indomethacin is an anti-inflammatory drug that causes ulcers on the gastric mucosa due to its use. Probiotic bacteria are live microorganisms, and it has been stated by various studies that these bacteria have antioxidant and anti-inflammatory effects. In this study, we investigated the possible protective effect of various types of probiotic bacteria (Lactobacillus rhamnosus, Lactobacillus fermentum, and Lactobacillus brevis) against acute gastric mucosal damage caused by indomethacin.

METHODS

Control group - Physiological saline was administered daily for 10 days. Indo group-Physiological saline was administered daily for 10 days. Ranitidine + Indo group 5 mg/kg ranitidine dose was administered daily for 5 days. On day 11, a single dose of 100 mg/kg of indomethacin was given to the same group. Probiotic + Indo group 1 ml/kg of oral probiotic bacteria was administered daily for 10 days. On day 11, a single 100 mg/kg dose of indomethacin was given. After the application, the rats were anesthetized with ketamine xylazine, killed under appropriate conditions, the abdominal cavity was opened and the stomach tissues were removed. The obtained gastric tissues were used in the biochemical and histopathological analyses discussed below. All data were statistically evaluated by one-way ANOVA using SPSS 20.00, followed by Duncan Post hoc test. The data were expressed as mean ± SD. P < 0.05 was considered statistically significant.

RESULTS

As a result, the administration of indomethacin caused gastric damage, stimulating oxidative stress, inflammation, and apoptosis. We found that the use of probiotic bacteria reduces oxidative stress (TOC), increases the activity of antioxidant enzymes (TAC), suppresses inflammation (IL-6 and Tnf-α), and inhibits apoptosis (Bax and Bcl-2) (P < 0.05).

CONCLUSION

Probiotic treatment can mitigate gastric damage and apoptosis caused by indomethacin-induced gastric damage in rats. Probiotic also enhances the restoration of biochemical oxidative enzymes as it has anti-inflammatory, antioxidant, and antiapoptotic properties.

The hepatotoxicity of γ-radiation synthesized 5-fluorouracil nanogel versus 5-fluorouracil in rats model

INTRODUCTION

The clinical use of 5-fluorouracil (5-FU), a routinely used chemotherapy medication, has a deleterious impact on the liver. Therefore, it is necessary to find a less harmful alternative to minimize liver damage. This study was designed to see how 5-fluorouracil nanogel influenced 5-FU-induced liver damage in rats.

METHODS

To induce liver damage, male albino rats were injected intraperitoneally with 5-FU (12.5 mg/kg) three doses/week for 1 month. The histopathological examination together with measuring the activities of serum alanine and aspartate aminotransferase enzymes (ALT and AST) were used to evaluate the severity of liver damage besides, hepatic oxidative stress and antioxidant markers were also measured. The hepatic gene expression of heme oxygenase-1 (HO-1), nuclear factor erythroid 2-related factor 2 (Nrf2) and its inhibitor Kelch-like ECH-associated protein-1(Keap-1) in addition to hepatic inflammatory mediators including tumor necrosis factor-α (TNF- α) and interleukins (IL-1β, IL-6) were detected.

RESULTS

5-Fu nanogel effectively attenuated 5-FU-induced liver injury by improving the hepatic structure and function (ALT and AST) besides the suppression of the hepatic inflammatory mediators (TNF- α, IL-1β and IL-6). Additionally, 5-FU nanogel alleviated the impaired redox status and restored the antioxidant system via maintaining the cellular homeostasis Keap-1/Nrf2/HO-1 pathway.

CONCLUSION

Consequently, 5-Fu nanogel exhibited lower liver toxicity compared to 5-FU, likely due to the alleviation of hepatic inflammation and the regulation of the cellular redox pathway.

The immunological mechanisms and therapeutic potential in drug-induced liver injury: lessons learned from acetaminophen hepatotoxicity

Acute liver failure caused by drug overdose is a significant clinical problem in developed countries. Acetaminophen (APAP), a widely used analgesic and antipyretic drug, but its overdose can cause acute liver failure. In addition to APAP-induced direct hepatotoxicity, the intracellular signaling mechanisms of APAP-induced liver injury (AILI) including metabolic activation, mitochondrial oxidant stress and proinflammatory response further affect progression and severity of AILI. Liver inflammation is a result of multiple interactions of cell death molecules, immune cell-derived cytokines and chemokines, as well as damaged cell-released signals which orchestrate hepatic immune cell infiltration. The immunoregulatory interplay of these inflammatory mediators and switching of immune responses during AILI lead to different fate of liver pathology. Thus, better understanding the complex interplay of immune cell subsets in experimental models and defining their functional involvement in disease progression are essential to identify novel therapeutic targets for the treatment of AILI. Here, this present review aims to systematically elaborate on the underlying immunological mechanisms of AILI, its relevance to immune cells and their effector molecules, and briefly discuss great therapeutic potential based on inflammatory mediators.

Hepatic bile acid synthesis and secretion: Comparison of in vitro methods

Reliable hepatic in vitro systems are crucial for the safety assessment of xenobiotics. Certain xenobiotics decrease the hepatic bile efflux, which can ultimately result in cholestasis. Preclinical animal models and the currently available in vitro systems poorly predict a xenobiotic's cholestatic potential. Here, we compared the phenotype and capacity of three liver derived in vitro systems to emulate human functionality to synthesize and secrete bile acids (BAs). To this end, basal BA production of sandwich cultured human hepatocytes (SCHHs), HepaRG cells (HepaRGs) and hepatocyte-like intrahepatic cholangiocyte organoids (ICO-heps) were analysed, and the effect of the known BSEP (Bile Salt Export Pump)-inhibitors bosentan and lopinavir on BA disposition in SCHHs and HepaRGs was quantified. RT-qPCR of selected target genes involved in maturation status, synthesis, transport and conjugation of BAs was performed to mechanistically underpin the observed differences in BA homeostasis. ICO-heps produced a (very) low amount of BAs. SCHHs are a powerful tool in cholestasis-testing due to their high basal BA production and high transporter expression compared to the other models tested. HepaRGs were responsive to both selected BSEP-inhibitors and produced a BA profile that is most similar to the human in vivo situation, making them a suitable and practical candidate for cholestasis-testing.

Role of Platelet-activating factor and HO-1 in mediating the protective effect of rupatadine against 5-fluorouracil-induced hepatotoxicity in rats

5-fluorouracil (5-FU) is a widely used chemotherapeutic drug, but its hepatotoxicity challenges its clinical use. Thus, searching for a hepatoprotective agent is highly required to prevent the accompanied hepatic hazards. The current study aimed to investigate the potential benefit and mechanisms of action of rupatadine (RU), a Platelet-activating factor (PAF) antagonist, in the prevention of 5-FU-related hepatotoxicity in rats. Hepatotoxicity was developed in male albino rats by a single 5-FU (150 mg/kg) intra-peritoneal injection on the 7th day of the experiment. RU (3 mg/kg/day) was orally administrated to the rodents for 10 days. Hepatic toxicity was assessed by measuring both liver and body weights, serum alanine aminotransferase and aspartate aminotransferase (ALT and AST), hepatic oxidative stress parameters (malondialdehyde (MDA), nitric oxide levels (NOx), reduced glutathione (GSH), superoxide dismutase (SOD)), and heme oxygenase-1 (HO-1). Inflammatory markers expressions (inducible nitric oxide synthase (iNOS), tumor necrosis factor-alpha (TNFα), interleukins; IL-1B, IL-6), the apoptotic marker (caspase-3), and PAF were measured in the hepatic tissue. 5-FU-induced hepatotoxicity was proved by the biochemical along with histopathological assessments. RU ameliorated 5-FU-induced liver damage as proved by the improved serum ALT, AST, and hepatic oxidative stress parameters, the attenuated expression of hepatic pro-inflammatory cytokines and PAF, and the up-regulation of HO-1. Therefore, it can be concluded that RU pretreatment exerted a hepatoprotective effect against 5-FU-induced liver damage through both its powerful anti-inflammatory, antioxidant, and anti-apoptotic effect.

Isoflurane induces liver injury by modulating the expression of miR-125a-5p

BACKGROUND

Isoflurane can cause hepatotoxicity, and microRNAs (miRNAs) are involved in the regulation of liver injury. Therefore, this study aimed to explore the effect of miR-125a-5p on isoflurane-induced liver injury.

BASIC PROCEDURES

Sprague-Dawley (SD) male rats and BRL-3A cells were exposed to isoflurane to construct animal and cell models. Serum alanine transaminase (ALT) and aspartate transaminase (AST) levels of rats were detected. RT-qPCR was performed for the measurement of miR-125a-5p levels. Cell proliferation and apoptosis were also detected.

MAIN FINDINGS

After isoflurane treatment, serum ALT and AST levels of rats increased in a time-dependent manner, and the differences reached significant levels from 3 days after isoflurane treatment. MiR-125a-5p levels increased significantly in the liver tissues of isoflurane-treated rats. MiR-125a-5p downregulation significantly attenuated isoflurane-induced increasing trend of serum ALT and AST levels in rats. In BRL-3A cells, isoflurane treatment significantly inhibited cell proliferation and promoted cell apoptosis, which was reversed by miR-125a-5p downregulation.

PRINCIPAL CONCLUSIONS

Isoflurane exposure significantly elevates the level of miR-125a-5p in the liver tissues of rats. Downregulation of miR-125a-5p may protect against isoflurane-induced liver injury through regulating liver cell proliferation and apoptosis. Dysregulation of miR-125a-5p might be a possible mechanism of isoflurane-induced liver injury.

Circulatory Inflammatory Mediators in the Prediction of Anti-Tuberculous Drug-Induced Liver Injury Using RUCAM for Causality Assessment

BACKGROUND

Anti-tuberculous (TB) medications are common causes of drug-induced liver injury (DILI). Limited data are available on systemic inflammatory mediators as biomarkers for predicting DILI before treatment. We aimed to select predictive markers among potential candidates and to formulate a predictive model of DILI for TB patients.

METHODS

Adult active TB patients from a prospective cohort were enrolled, and all participants received standard anti-tuberculous treatment. Development of DILI, defined as ≥5× ULN for alanine transaminase or ≥2.6× ULN of total bilirubin with causality assessment (RUCAM, Roussel Uclaf causality assessment method), was regularly monitored. Pre-treatment plasma was assayed for 15 candidates, and a set of risk prediction scores was established using Cox regression and receiver-operating characteristic analyses.

RESULTS

A total of 19 (7.9%) in 240 patients developed DILI (including six carriers of hepatitis B virus) following anti-TB treatment. Interleukin (IL)-22 binding protein (BP), interferon gamma-induced protein 1 (IP-10), soluble CD163 (sCD163), IL-6, and CD206 were significant univariable factors associated with DILI development, and the former three were backward selected as multivariable factors, with adjusted hazards of 0.20 (0.07-0.58), 3.71 (1.35-10.21), and 3.28 (1.07-10.06), respectively. A score set composed of IL-22BP, IP-10, and sCD163 had an improved area under the curve of 0.744 (p < 0.001).

CONCLUSIONS

Pre-treatment IL-22BP was a protective biomarker against DILI development under anti-TB treatment, and a score set by additional risk factors of IP-10 and sCD163 employed an adequate DILI prediction.

Hepatotoxicity of FDA-approved small molecule kinase inhibitors

Introduction: Given their importance in cellular processes and association with numerous diseases, protein kinases have emerged as promising targets for drugs. The FDA has approved greater than fifty small molecule kinase inhibitors (SMKIs) since 2001. Nevertheless, severe hepatotoxicity and related fatal cases have grown as a potential challenge in the advancement of these drugs, and the identification and diagnosis of drug-induced liver injury (DILI) are thorny problems for clinicians.Areas covered: This article summarizes the progression and analyzes the significant features in the study of SMKI hepatotoxicity, including clinical observations and investigations of the underlying mechanisms.Expert opinion: The understanding of SMKI-associated hepatotoxicity relies on the development of preclinical models and improvement of clinical assessment. With a full understanding of the role of inflammation in DILI and the mediating role of cytokines in inflammation, cytokines are promising candidates as sensitive and specific biomarkers for DILI. The emergence of three-dimensional spheroid models demonstrates potential use in providing clinically relevant data and predicting hepatotoxicity of SMKIs.

Screening for Susceptibility-Related Factors and Biomarkers of Xianling Gubao Capsule-Induced Liver Injury

Although increasing reports from the literature on herbal-related hepatotoxicity, the identification of susceptibility-related factors and biomarkers remains challenging due to idiosyncratic drug-induced liver injury (IDILI). As a well-known Chinese medicine prescription, Xianling Gubao Capsule (XLGB) has attracted great attention due to reports of potential liver toxicity. But the mechanism behind it is difficult to determine. In this paper, we found that XLGB-induced liver injury belongs to IDILI through the analysis of clinical liver injury cases. In toxicological experiment assessment, co-exposure to XLGB and non-toxic dose of lipopolysaccharide (LPS) could cause evident liver injury as manifested by significantly increased plasma alanine aminotransferase activity and obvious liver histological damage. However, it failed to induce observable liver injury in normal rats, suggesting that mild immune stress may be a susceptibility factor for XLGB-induced idiosyncratic liver injury. Furthermore, plasma cytokines were determined and 15 cytokines (such as IL-1β, IFN-γ, and MIP-2α etc) were acquired by receiver operating characteristic (ROC) curves analysis. The expression of these 15 cytokines in LPS group was significantly up-regulated in contrast to the normal group. Meanwhile, the metabolomics profile showed that mild immune stress caused metabolic reprogramming, including sphingolipid metabolism, phenylalanine metabolism, and glycerophospholipid metabolism. 8 potential biomarkers (such as sphinganine, glycerophosphoethanolamine, and phenylalanine etc.) were identified by correlation analysis. Therefore, these results suggested that intracellular metabolism and immune changes induced by mild immune stress may be important susceptibility mechanisms for XLGB IDILI.

Robustness testing and optimization of an adverse outcome pathway on cholestatic liver injury

Adverse outcome pathways (AOPs) have been recently introduced as tools to map the mechanisms underlying toxic events relevant for chemical risk assessment. AOPs particularly depict the linkage between a molecular initiating event and an adverse outcome through a number of intermediate key events. An AOP has been previously introduced for cholestatic liver injury. The objective of this study was to test the robustness of this AOP for different types of cholestatic insult and the in vitro to in vivo extrapolation. For this purpose, in vitro samples from human hepatoma HepaRG cell cultures were exposed to cholestatic drugs (i.e. intrahepatic cholestasis), while in vivo samples were obtained from livers of cholestatic mice (i.e. extrahepatic cholestasis). The occurrence of cholestasis in vitro was confirmed through analysis of bile transporter functionality and bile acid analysis. Transcriptomic analysis revealed inflammation and oxidative stress as key events in both types of cholestatic liver injury. Major transcriptional differences between intrahepatic and extrahepatic cholestatic liver insults were observed at the level of cell death and metabolism. Novel key events identified by pathway analysis included endoplasmic reticulum stress in intrahepatic cholestasis, and autophagy and necroptosis in both intrahepatic as extrahepatic cholestasis. This study demonstrates that AOPs constitute dynamic tools that should be frequently updated with new input information.

Metabolomics and Cytokine Analysis for Identification of Severe Drug-Induced Liver Injury

AIM

To evaluate the levels of metabolites and cytokines in the serum of patients with severe and non-severe idiosyncratic drug-induced liver injury (DILI) and to identify biomarkers of DILI severity.

METHODS

Gas chromatography-mass spectrometry (GC-MS) and ultraperformance liquid chromatography-mass spectrometry (UPLC-MS) based metabolomic approaches were used to evaluate the metabolome of serum samples from 29 DILI patients of severity grade 3 (non-severe), 27 of severity grade 4 (severe), and 36 healthy control (HC). The levels of total keratin-18 (K18), fragment K18, and 27 cytokines were determined by enzyme-linked immunosorbent assay.

RESULTS

The alkaline phosphatase activity ( p = 0.021) and international normalized ratio (INR) ( p < 0.001) differed significantly between the severe and non-severe groups. The severe group had a higher serum fragment K18 level than the non-severe group. A multivariate analysis showed good separation between all pairs of the HC, non-severe, and severe groups. According to the orthogonal partial least-squares-discriminant analysis (OPLS-DA) model, 14 metabolites were selected by GC-MS and 17 by UPLC-MS. Among these metabolites, the levels of 16 were increased and of 15 were decreased in the severe group. A pathway analysis revealed major changes in the primary bile acid biosynthesis and alpha-linolenic acid metabolic pathways. The levels of PDGF-bb, IP-10, IL-1Rα, MIP-1β, and TNF-α differed significantly between the severe and non-severe groups, and the levels of most of the metabolites were negatively correlated with those of these cytokines. An OPLS-DA model that included the detected metabolites and cytokines revealed clear separation of the severe and non-severe groups.

CONCLUSION

We identified 31 metabolites and 5 cytokines related to the severity of idiosyncratic DILI. The primary bile acid biosynthesis and alpha-linolenic acid metabolism pathways were also related to the severity of DILI. A model that incorporated the metabolites and cytokines showed clear separation between patients with severe and non-severe DILI, suggesting that these biomarkers have potential as indicators of DILI severity.

Mechanisms and in vitro models of drug-induced cholestasis

Cholestasis underlies one of the major manifestations of drug-induced liver injury. Drug-induced cholestatic liver toxicity is a complex process, as it can be triggered by a variety of factors that induce 2 types of biological responses, namely a deteriorative response, caused by bile acid accumulation, and an adaptive response, aimed at removing the accumulated bile acids. Several key events in both types of responses have been characterized in the past few years. In parallel, many efforts have focused on the development and further optimization of experimental cell culture models to predict the occurrence of drug-induced cholestatic liver toxicity in vivo. In this paper, a state-of-the-art overview of mechanisms and in vitro models of drug-induced cholestatic liver injury is provided.

Susceptibility-Related Factor and Biomarkers of Dietary Supplement Polygonum multiflorum-Induced Liver Injury in Rats

Polygonum multiflorum [PM, synonym Reynoutria multiflora (Thunb.) Moldenke.], a well-known and commonly used Traditional Chinese Medicine and herbal dietary supplement for nourishing the kidney and liver, etc., has aroused wide concern for its reported potential hepatotoxicity. Previous clinical cases and experimental studies have suggested that mild immune stress (MIS) may be one of the susceptibility-related factors of idiosyncratic drug-induced liver injury (IDILI) caused by PM. In this paper, we found that the same dose of PM caused abnormal liver biochemical indicators and liver tissue damage in MIS model rats, while it did not result in liver injury in normal rats, further confirming that MIS is a susceptibility factor for PM-IDILI. Plasma chemokine/cytokine profiling indicated that the MIS model group was significantly different from the other groups, showing a significant upregulation of plasma chemokines, while the MIS/PM group showed upregulated expression of chemokines or pro-inflammatory cytokines. Liver histopathological examination indicated a small amount of inflammatory cytokine infiltration in the MIS group, but no hepatocyte injury, consistent with the plasma profiles of increased chemokines and unchanged inflammatory cytokines. Notably, metabolomics characterization showed that MIS caused reprogramming of these metabolic pathways (such as phenylalanine and glutamate pathways), which was associated with acute phase reactions and inflammatory responses. These results suggested that MIS may promote an immune response to the initial cellular injury induced by PM in the liver, and MIS-induced upregulation of chemokines and metabolic reprogramming may an important mechanism that mediates the susceptibility to PM-IDILI. Furthermore, via receiver operating characteristic (ROC) curves analysis, we identified 12 plasma cytokines (e.g., IP-10, MCP-1 and MIP-1α) and nine metabolomics biomarkers (e.g., L-Phenylalanine, Creatinine, and L-glutamine) with differential capabilities (all ROC AUC > 0.9) of identifying susceptibility model animals from normal ones, which might be of referable value for the clinical recognition of PM-IDILI susceptible individuals.

Incidence, clinical features, and risk factors of fluoroquinolone-induced acute liver injury: a case-control study

Background

Fluoroquinolone-related hepatotoxicity is rare but serious and is attracting increasing attention. We explored the incidence, clinical features and risk factors of acute liver injury associated with fluoroquinolone use.

Materials and methods

Based on the Adverse Drug Events Active Surveillance and Assessment System that we developed, we carried out a case-control study by enrolling patients who were hospitalized and received fluoroquinolones to treat or prevent infections at the Chinese People's Liberation Army General Hospital from Jan 2016 to Dec 2017. The incidence of fluoroquinolone-induced acute liver injury was estimated, and logistic regression was used to reveal the risk factors of this adverse reaction.

Results

We found that 17,822 patients received fluoroquinolones, and 13,678 of them met the inclusion criteria. A total of 91 patients developed acute liver injury after receiving the medication, and 369 controls were matched to these patients. The overall incidence of fluoroquinolone-induced acute liver injury in the Chinese population is approximately 6-7 cases per 1,000 individuals annually. Multivariate logistic regression analysis showed that older age slightly decreased the risk of hepatotoxicity (OR, 0.98; 95% CI, 0.96-0.99). The male sex (OR, 2.19; 95% CI, 1.07-4.48), alcohol abuse (OR, 2.91; 95% CI, 1.39-6.11) and hepatitis B carrier status (OR, 2.38; 95% CI, 1.04-5.48) increased the risk of liver injury. Concurrent use of cephalosporins or carbapenems was also associated with an increased risk.

Conclusion

Increased risk of fluoroquinolone-related hepatotoxicity may be associated with youth, the male sex, alcohol abuse, hepatitis B carrier status and the concurrent use of cephalosporins or carbapenems.

Mechanisms of Drug-Induced Cholestasis

Cholestasis can be defined as any situation of impaired bile secretion with concomitant accumulation of bile acids in the liver or in the systemic circulation. A variety of factors may evoke cholestasis, including genetic disorders, metabolic pathologies, infectious diseases, immunogenic stimuli, and drugs. Drug-induced cholestasis is a mechanistically complex process. At least three triggering factors of drug-induced cholestasis have been described, including effects on drug transporters, various hepatocellular changes, and altered bile canaliculi dynamics. These stimuli induce two cellular responses, each typified by a number of key events, namely a deteriorative response activated by bile acid accumulation and an adaptive response aimed at decreasing the uptake and increasing the export of bile acids into and from the liver, respectively. The mechanistic scenario of drug-induced cholestasis is described in this chapter.

Primary hepatocytes and their cultures for the testing of drug-induced liver injury

Drug-induced liver injury is a major reason for discontinuation of drug development and withdrawal of drugs from the market. Intensive efforts in the last decades have focused on the establishment and finetuning of liver-based in vitro models for reliable prediction of hepatotoxicity triggered by drug candidates. Of those, primary hepatocytes and their cultures still are considered the gold standard, as they provide an acceptable reflection of the hepatic in vivo situation. Nevertheless, these in vitro systems cope with gradual deterioration of the differentiated morphological and functional phenotype. The present paper gives an overview of traditional and more recently introduced strategies to counteract this dedifferentiation process in an attempt to set up culture models that can be used for long-term testing purposes. The relevance and applicability of such optimized cultures of primary hepatocytes for the testing of drug-induced cholestatic liver injury is demonstrated.

Dissecting the molecular pathophysiology of drug-induced liver injury

Drug-induced liver injury (DILI) has become a major topic in the field of Hepatology and Gastroenterology. DILI can be clinically divided into three phenotypes: hepatocytic, cholestatic and mixed. Although the clinical manifestations of DILI are variable and the pathogenesis complicated, recent insights using improved preclinical models, have allowed a better understanding of the mechanisms that trigger liver damage. In this review, we will discuss the pathophysiological mechanisms underlying DILI. The toxicity of the drug eventually induces hepatocellular damage through multiple molecular pathways, including direct hepatic toxicity and innate and adaptive immune responses. Drugs or their metabolites, such as the common analgesic, acetaminophen, can cause direct hepatic toxicity through accumulation of reactive oxygen species and mitochondrial dysfunction. The innate and adaptive immune responses play also a very important role in the occurrence of idiosyncratic DILI. Furthermore, we examine common forms of hepatocyte death and their association with the activation of specific signaling pathways.

Models of Drug Induced Liver Injury (DILI) - Current Issues and Future Perspectives

BACKGROUND

Drug-induced Liver Injury (DILI) is an important cause of acute liver failure cases in the United States, and remains a common cause of withdrawal of drugs in both preclinical and clinical phases.

METHODS

A structured search of bibliographic databases - Web of Science Core Collection, Scopus and Medline for peer-reviewed articles on models of DILI was performed. The reference lists of relevant studies was prepared and a citation search for the included studies was carried out. In addition, the characteristics of screened studies were described.

RESULTS

One hundred and six articles about the existing knowledge of appropriate models to study DILI in vitro and in vivo with special focus on hepatic cell models, variations of 3D co-cultures, animal models, databases and predictive modeling and translational biomarkers developed to understand the mechanisms and pathophysiology of DILI are described.

CONCLUSION

Besides descriptions of current applications of existing modeling systems, associated advantages and limitations of each modeling system and future directions for research development are discussed as well.

An Update on Adverse Outcome Pathways Leading to Liver Injury

Chemical-induced liver injury can be manifested in a number of ways, such as cholestasis, steatosis, fibrosis, and cancer. The mechanisms driving these toxicological processes have been well characterized and have been embedded in adverse outcome pathway frameworks in recent years. This article provides a concise overview of these constructs.

Test systems in drug discovery for hazard identification and risk assessment of human drug-induced liver injury

INTRODUCTION

The liver is an important target for drug-induced toxicities. Early detection of hepatotoxic drugs requires use of well-characterized test systems, yet current knowledge, gaps and limitations of tests employed remains an important issue for drug development. Areas Covered: The current state of the science, understanding and application of test systems in use for the detection of drug-induced cytotoxicity, mitochondrial toxicity, cholestasis and inflammation is summarized. The test systems highlighted herein cover mostly in vitro and some in vivo models and endpoint measurements used in the assessment of small molecule toxic liabilities. Opportunities for research efforts in areas necessitating the development of specific tests and improved mechanistic understanding are highlighted. Expert Opinion: Use of in vitro test systems for safety optimization will remain a core activity in drug discovery. Substantial inroads have been made with a number of assays established for human Drug-induced Liver Injury. There nevertheless remain significant gaps with a need for improved in vitro tools and novel tests to address specific mechanisms of human Drug-Induced Liver Injury. Progress in these areas will necessitate not only models fit for application, but also mechanistic understanding of how chemical insult on the liver occurs in order to identify translational and quantifiable readouts for decision-making.

Protective Effect of 18β-Glycyrrhetinic Acid against Triptolide-Induced Hepatotoxicity in Rats

Triptolide (TP) is the major active component of Tripterygium wilfordii Hook F (TWHF) and possesses multiple pharmacological effects. However, hepatotoxicity of TP which is one of the toxic properties slows its progression in clinical application. 18β-Glycyrrhetinic acid (GA) is the main bioactive ingredient of Licorice (Glycyrrhiza glabra L.), a herbal medicine famous for its detoxification. This study aims to investigate whether GA possesses protective effect against TP-induced hepatotoxicity in rats. TP interference markedly elevated serum levels of ALT, AST, and ALP, caused evident liver histopathological changes, and elevated hepatic TNF-α, IL-6, IL-1β, and IFN-γ as well as nuclear translocation of NF-κB. TP also significantly elevated liver MDA and declined hepatic activities of SOD, CAT, and GSH-Px. Assay of TUNEL and apoptosis proteins (Bax, Bcl-2, and active caspase-3) showed that TP induced severe hepatocellular apoptosis. In contrast, low-dose GA (50 mg/kg) significantly reversed TP-induced changes above. However, high-dose GA (100 mg/kg) had no such effect. Overall, these findings indicated that low-dose GA but not high-dose GA exhibited a protective effect against TP-induced hepatotoxicity in rats by anti-inflammation, antioxidation, and antiapoptosis, which suggests that the doses of GA/Licorice should be carefully considered when used together with TWHF or TWHF preparations.

Idiosyncratic Drug-Induced Liver Injury (IDILI): Potential Mechanisms and Predictive Assays

Idiosyncratic drug-induced liver injury (IDILI) is a significant source of drug recall and acute liver failure (ALF) in the United States. While current drug development processes emphasize general toxicity and drug metabolizing enzyme- (DME-) mediated toxicity, it has been challenging to develop comprehensive models for assessing complete idiosyncratic potential. In this review, we describe the enzymes and proteins that contain polymorphisms believed to contribute to IDILI, including ones that affect phase I and phase II metabolism, antioxidant enzymes, drug transporters, inflammation, and human leukocyte antigen (HLA). We then describe the various assays that have been developed to detect individual reactions focusing on each of the mechanisms described in the background. Finally, we examine current trends in developing comprehensive models for examining these mechanisms. There is an urgent need to develop a panel of multiparametric assays for diagnosing individual toxicity potential.

A New Structure-Activity Relationship (SAR) Model for Predicting Drug-Induced Liver Injury, Based on Statistical and Expert-Based Structural Alerts

The prompt identification of chemical molecules with potential effects on liver may help in drug discovery and in raising the levels of protection for human health. Besides in vitro approaches, computational methods in toxicology are drawing attention. We built a structure-activity relationship (SAR) model for evaluating hepatotoxicity. After compiling a data set of 950 compounds using data from the literature, we randomly split it into training (80%) and test sets (20%). We also compiled an external validation set (101 compounds) for evaluating the performance of the model. To extract structural alerts (SAs) related to hepatotoxicity and non-hepatotoxicity we used SARpy, a statistical application that automatically identifies and extracts chemical fragments related to a specific activity. We also applied the chemical grouping approach for manually identifying other SAs. We calculated accuracy, specificity, sensitivity and Matthews correlation coefficient (MCC) on the training, test and external validation sets. Considering the complexity of the endpoint, the model performed well. In the training, test and external validation sets the accuracy was respectively 81, 63, and 68%, specificity 89, 33, and 33%, sensitivity 93, 88, and 80% and MCC 0.63, 0.27, and 0.13. Since it is preferable to overestimate hepatotoxicity rather than not to recognize unsafe compounds, the model's architecture followed a conservative approach. As it was built using human data, it might be applied without any need for extrapolation from other species. This model will be freely available in the VEGA platform.

Redox-Dependent HMGB1 Isoforms as Pivotal Co-Ordinators of Drug-Induced Liver Injury: Mechanistic Biomarkers and Therapeutic Targets

SIGNIFICANCE

High-mobility group box 1 (HMGB1) is a critical protein in the coordination of the inflammatory response in drug-induced liver injury (DILI). HMGB1 is released from necrotic hepatocytes and activated immune cells. The extracellular function of HMGB1 is dependent upon redox modification of cysteine residues that control chemoattractant and cytokine-inducing properties. Existing biomarkers of DILI such as alanine aminotransferase (ALT) have limitations such as lack of sensitivity and tissue specificity that can adversely affect clinical intervention.

RECENT ADVANCES

HMGB1 isoforms have been shown to be more sensitive biomarkers than ALT for predicting DILI development and the requirement for liver transplant following acetaminophen (APAP) overdose. Hepatocyte-specific conditional knockout of HMGB1 has demonstrated the pivotal role of HMGB1 in DILI and liver disease. Tandem mass spectrometry (MS/MS) enables the characterization and quantification of different mechanism-dependent post-translationally modified isoforms of HMGB1.

CRITICAL ISSUES

HMGB1 shows great promise as a biomarker of DILI. However, current diagnostic assays are either too time-consuming to be clinically applicable (MS/MS) or are unable to distinguish between different redox and acetyl isoforms of HMGB1 (ELISA). Additionally, HMGB1 is not liver specific, so while it outperforms ALT (also not liver specific) as a biomarker for the prediction of DILI development, it should be used in a biomarker panel along with liver-specific markers such as miR-122.

FUTURE DIRECTIONS

A point-of-care test for HMGB1 and the development of redox and acetyl isoform-targeting antibodies will advance clinical utility. Work is ongoing to validate baseline levels of circulating HMGB1 in healthy volunteers.

Circulating Fibroblast Growth Factor 21 Is A Sensitive Biomarker for Severe Ischemia/reperfusion Injury in Patients with Liver Transplantation

Hepatic ischemia/reperfusion (I/R) injury is a major cause of morbidity and mortality after liver surgery. Therefore, it is important to identity reliable biomarkers to assist early diagnosis of hepatic I/R injury. This study aimed to investigate the potential of serum levels of fibroblast growth factor 21 (FGF21) as a biomarker for hepatic I/R injury in patients with liver transplantation. Two independent cohorts of liver transplantation patients were recruited for determination of serum levels of FGF21, ALT, and AST. The results demonstrated that serum FGF21 at 2 hours post-reperfusion in cohort-1 exhibited an approximately 20-fold elevation relative to those in healthy subjects. In blood samples dynamically collected in cohort-2, a dramatic increase in serum FGF21 levels (~25-fold) was observed at two hours after surgery, whereas the peak levels of serum ALT and AST were detected only after 24 hours. Temporal correlation analysis demonstrated a significant association of peak serum levels of FGF21 at 2 hours with the magnitude of the increase in both serum ALT and AST levels at 24 hours post transplantation. In conclusion, serum FGF21 may represent a sensitive and specific prognostic biomarker for early detection of I/R injury in patients with liver transplantation.

Efficacy of coupled low-volume plasma exchange with plasma filtration adsorption in treating pigs with acute liver failure: A randomised study

BACKGROUND & AIMS

Extracorporeal blood purification systems for supportive therapy of liver failure are widely used. We developed a novel blood purification system, named Li's artificial liver system (Li-ALS), which couples low-volume plasma exchange (low-volume PE) with plasma filtration adsorption (PFA). This study aims to evaluate the efficacy of our novel system in pigs with acute liver failure (ALF).

METHODS

Thirty-two pigs were infused with D-galactosamine (1.3g/kg) to induce ALF. All animals were equally and randomly divided into four groups: the ALF control group received intensive care, the PFA group underwent five hour plasma recycling filtration and adsorption purification, the low-volume PE group received one hour low-volume PE, and the Li-ALS group underwent one hour low-volume PE, followed by five hour PFA. Intervention was initiated 36hours after drug administration. The efficacy of each treatment was assessed by survival time and improvement in hematological, biochemical, and immunohistological parameters.

RESULTS

Pigs in the Li-ALS group survived longer than those in the other groups (p<0.001, ALF control: 60±2h; PFA group: 74±2h; low-volume PE group: 75±2h; and Li-ALS group: 90±3h). Liver enzyme, bilirubin, bile acid and blood ammonia levels were decreased significantly after Li-ALS treatment, and increases in inflammatory cytokines were ameliorated. A higher hepatocyte regeneration index was also observed in the Li-ALS group.

CONCLUSION

Our novel Li-ALS could expedite liver regeneration and improve survival time; hence, it could be promising for treating ALF.

Adverse Outcome Pathways and Drug-Induced Liver Injury Testing

Drug-induced liver injury is a prominent reason for premarketing and postmarketing drug withdrawal and can be manifested in a number of ways, such as cholestasis, steatosis, and fibrosis. The mechanisms driving these toxicological processes have been well characterized and have been emdedded in adverse outcome pathway frameworks in recent years. This review evaluates these constructs and simultaneously illustrates their use in the preclinical testing of drug-induced liver injury.

Immunological aspects of drug-induced liver injury

Drug induced liver injury (DILI) is a common condition of increasing incidence. Many environmental and genetic factors are involved in its pathogenesis, and immunological mechanisms are also thought to contribute to the development and severity of DILI. This review summarizes current understanding of the immunological pathogenesis of DILI and discusses the perspective for clinical applications.

Development of blood biomarkers for drug-induced liver injury: an evaluation of their potential for risk assessment and diagnostics

Drug-induced liver injury (DILI) remains a rare but serious complication in drug therapy that is a primary cause of drug failure during clinical trials. Conventional biomarkers, particularly the serum transaminases and bilirubin, serve as useful indicators of hepatocellular or cholestatic liver injury, respectively, but only after substantial and sometimes irreversible tissue damage. Ideally, more sensitive biomarkers that respond very early before irreversible injury has occurred would offer improved outcomes. Novel biomarkers are initially being developed in animal models exposed to intrinsically hepatotoxic stimuli. However, the eventual translation to human populations, even those with known risk factors that predispose the liver to drug toxicity, would be the fundamental goal. Ultimately, some might even be applicable for the early identification of individuals predisposed to idiosyncratic hepatotoxicity potential. This article reviews recent progress in the discovery and qualification of novel biomarkers for DILI and delineates the path to eventual utilization for risk assessment. Some major categories of plasma or serum biomarkers surveyed include proteins, cytokines, circulating mRNAs, and microRNAs.

Quercetin prevents pyrrolizidine alkaloid clivorine-induced liver injury in mice by elevating body defense capacity

Quercetin is a plant-derived flavonoid that is widely distributed in nature. The present study is designed to analyze the underlying mechanism in the protection of quercetin against pyrrolizidine alkaloid clivorine-induced acute liver injury in vivo. Serum transaminases, total bilirubin analysis, and liver histological evaluation demonstrated the protection of quercetin against clivorine-induced liver injury. Terminal dUTP nick end-labeling assay demonstrated that quercetin reduced the increased amount of liver apoptotic cells induced by clivorine. Western-blot analysis of caspase-3 showed that quercetin inhibited the cleaved activation of caspase-3 induced by clivorine. Results also showed that quercetin reduced the increase in liver glutathione and lipid peroxidative product malondialdehyde induced by clivorine. Quercetin reduced the enhanced liver immunohistochemical staining for 4-hydroxynonenal induced by clivorine. Results of the Mouse Stress and Toxicity PathwayFinder RT² Profiler PCR Array demonstrated that the expression of genes related with oxidative or metabolic stress and heat shock was obviously altered after quercetin treatment. Some of the alterations were confirmed by real-time PCR. Our results demonstrated that quercetin prevents clivorine-induced acute liver injury in vivo by inhibiting apoptotic cell death and ameliorating oxidative stress injury. This protection may be caused by the elevation of the body defense capacity induced by quercetin.

Keratin-18 and microRNA-122 complement alanine aminotransferase as novel safety biomarkers for drug-induced liver injury in two human cohorts

BACKGROUND & AIMS

There is a demand for more sensitive, specific and predictive biomarkers for drug-induced liver injury (DILI) than the gold standard used today, alanine aminotransferase (ALT). The aim of this study was to qualify novel DILI biomarkers (keratin-18 markers M65/M30, microRNA-122, glutamate dehydrogenase and alpha-foetoprotein) in human DILI.

METHODS

Levels of the novel biomarkers were measured by enzyme-linked immunosorbent assay or real-time quantitative reverse-transcription PCR (qRT-PCR) in two human DILI cohorts: a human volunteer study with acetaminophen and a human immunodeficiency virus (HIV)/tuberculosis (TB) study.

RESULTS

In the acetaminophen study, serum M65 and microRNA-122 levels were significantly increased at an earlier time point than ALT. Furthermore, the maximal elevation of M65 and microRNA-122 exceeded the increase in ALT. In the HIV/TB study, all the analysed novel biomarkers increased after 1 week of treatment. In contrast to ALT, the novel biomarkers remained stable in a human cohort with exercise-induced muscular injury.

CONCLUSIONS

M65 and microRNA-122 are potential biomarkers of DILI superior to ALT with respect to sensitivity and specificity.

Th17/Treg imbalance in triptolide-induced liver injury

The study was designed to investigate the immune-modulatory effects of triptolide (TP) on CD4(+) T cell responses during liver injury. Previous studies have suggested that TP plays a critical role in modulating both innate and adaptive immune reactions, but its effects on the Th17/Treg balance during TP-induced liver injury remain unknown. In this study, female C57BL/6 mice were administered by oral gavage with TP at a dose of 250 or 500 μg/kg per mouse. We examined the plasma biochemical parameters, histopathological changes, hepatic frequencies of Th17 cells and Treg cells, hepatic expression of transcriptional factors and cytokine genes and hepatic interleukin (IL)-17 and IL-10 levels in TP-administered mice. Mice treated with TP displayed liver injury with markedly increased plasma transaminase as well as hepatic mRNA expression of retinoid related orphan receptor (ROR)-γt and hepatic IL-17 level at 24h. However, hepatic frequencies of Tregs and hepatic expression of forkhead/winged-helix family transcriptional repressor p3 (FoxP3) decreased at 24h after TP administration. Furthermore, we found that elevated serum biochemical parameters positively correlated with the Th17/Treg ratios. Taken together, these results revealed a novel and interesting phenomenon of TP in the enhancement of the expansion of Th17 cells and suppression of the production of Tregs during liver injury, which may represent a new pathogenesis of TP-induced liver injury.

Profiles of serum cytokines in acute drug-induced liver injury and their prognostic significance

Drug-induced liver injury (DILI) is the most common cause of acute liver failure in the United-States. The aim of the study was to describe serum immune profiles associated with acute DILI, to investigate whether there are profiles associated with clinical features or types of DILI and/or with prognosis, and to assess temporal changes in levels. Twenty-seven immune analytes were measured in the sera of 78 DILI subjects in the Drug-Induced Liver Injury Network (DILIN) and compared with 40 healthy controls. Immune analytes (14 cytokines, 7 chemokines and 6 growth factors) were measured by BioPlex multiplex ELISA at DILI onset and after 6 months. A modeling process utilizing immune principles was used to select a final set of variables among 27 immune analytes and several additional clinical lab values for prediction of early death (within 6 months of DILI onset). Nineteen of the 27 immune analytes were differentially expressed among healthy control, DILI onset and 6-month cohorts. Disparate patterns of immune responses, especially innate and adaptive cellular (mostly TH17) immunity were evident. Low values of four immune analytes (IL-9, IL-17, PDGF-bb and RANTES) and serum albumin are predictive of early death [PPV = 88% (95% CI, 65%-100%), NPV = 97% (95% CI, 93%-100%), accuracy = 96% (95% CI, 92%-100%)].

Idiosyncratic drug-induced liver injury: an update on the 2007 overview

INTRODUCTION

Idiosyncratic drug induced liver injury (DILI) is rare, with an incidence of approximately 19 per 100,000 treated individuals.

AREAS COVERED

An update on the epidemiology, pathogenic mechanisms, diagnosis, outcome, risk factors for idiosyncratic drug-induced hepatotoxicity, specific classes of drug hepatotoxicity and biomarkers to predict DILI are covered. Cumulative drug exposure and HLA phenotypes play an important role in the pathogenesis of DILI. Patients who present with suspected DILI and jaundice should have biliary obstruction and acute viral hepatitis, including hepatitis E excluded. Immune-mediated DILI will respond to steroid therapy. Patients with an elevated bilirubin and a hepatocellular pattern of liver function tests have severe liver injury with a mortality of greater than 10% and a risk of acute liver failure. Women have an increased risk of hepatocellular DILI. Antibiotics, anticonvulsants, and antidepressant therapy remain the commonest causes of DILI in the Western Hemisphere. Statin therapy rarely causes severe liver injury.

EXPERT OPINION

The establishment of prospective registries for DILI has provided valuable data on the pathogenesis and outcome of DILI. Drug-specific computerised causality assessment tools should improve the diagnosis of DILI. The clinical utility of genetic polymorphisms associated with drug-specific DILI is limited.

Latest advances in predicting DILI in human subjects: focus on biomarkers

INTRODUCTION

The quest for a biomarker that would reliably identify patients at risk of developing acute drug-induced liver injury (DILI) to a specific agent or class of agents before it occurs, has been underway for years. Historical host factors for DILI, such as older age and female gender, are not considered sufficient to truly predict an individual's inherent risk of DILI. In vitro and animal-based biomarker discoveries, in many instances, have not been considered accurate enough for drug development in human subjects nor for use in clinical practice.

AREAS COVERED

In order to assess the current state of biomarkers to predict idiosyncratic human DILI, the authors utilized the PubMed literature search tool to identify research reports dealing with clinical DILI biomarkers covering the period of 2010 through to June 2012. Studies involving pharmacogenetic, proteomic and toxicogenomic analyses are preferentially reviewed.

EXPERT OPINION

Although acute DILI has been linked to specific genetic associations (e.g., flucloxacillin and HLA-B*5701; and certain polymorphisms seen with anti-TB agent DILI), such predictors have been able to identify only some patients at risk for only a limited number of drugs. Proteomic-based biomarkers from stored sera in the US DILI Network, such as apolipoprotein E, have been identified as potential candidates, but require further study. As it currently stands, the quest for a widely applicable, validated DILI biomarker remains an ongoing clinical challenge.

Serum proteomic profiling in patients with drug-induced liver injury

BACKGROUND

Idiosyncratic drug-induced liver injury (DILI) is a complex disorder that is difficult to predict, diagnose and treat.

AIM

To describe the global serum proteome of patients with DILI and controls.

METHODS

A label-free, mass spectrometry-based quantitative proteomic approach was used to explore protein expression in serum samples from 74 DILI patients (collected within 14 days of DILI onset) and 40 controls. A longitudinal analysis was conducted in a subset of 21 DILI patients with available 6-month follow-up serum samples.

RESULTS

Comparison of DILI patients based on pattern, severity and causality assessment of liver injury revealed many differentially expressed priority 1 proteins among groups. Expression of fumarylacetoacetase was correlated with alanine aminotransferase (ALT; r = 0.237; P = 0.047), aspartate aminotransferase (AST; r = 0.389; P = 0.001) and alkaline phosphatase (r = -0.240; P = 0.043), and this was the only protein with significant differential expression when comparing patients with hepatocellular vs. cholestatic or mixed injury. In the longitudinal analysis, expression of 53 priority 1 proteins changed significantly from onset of DILI to 6-month follow-up, and nearly all proteins returned to expression levels comparable to control subjects. Ninety-two serum priority 1 proteins with significant differential expression were identified when comparing the DILI and control groups. Pattern analysis revealed proteins that are components of inflammation, immune system activation and several hepatotoxicity-specific pathways. Apolipoprotein E expression had the greatest power to differentiate DILI patients from controls (89% correct classification; AUROC = 0.97).

CONCLUSION

This proteomic analysis identified differentially expressed proteins that are components of pathways previously implicated in the pathogenesis of idiosyncratic drug-induced liver injury.