Frequency and pathological characteristics of drug-induced liver injury in a tertiary medical center

A gene expression profile-based approach to screen the occurrence and predisposed host characteristics of drug-induced liver injury: a case study of Psoralea corylifolia Linn

Drug-induced liver injury (DILI) is one of the most common causes of a drug being withdrawn, and identifying the culprit drugs and the host factors at risk of causing DILI has become a current challenge. Recent studies have found that immune status plays a considerable role in the development of DILI. In this study, DILI-related differentially expressed genes mediated by immunoinflammatory cytokines were obtained from the Gene Expression Omnibus (GEO) database to predict the occurrence of DILI (named the DILI predictive gene set, DILI_PGS), and the predictability of the DILI_PGS was verified using the Connectivity Map (CMap) and LiverTox platforms. The results obtained DILI_PGS from the GEO database could predict 81.25% of liver injury drugs. In addition, the Coexpedia platform was used to predict the DILI_PGS-related characteristics of common host diseases and found that the DILI_PGS mainly involved immune-related diseases and tumor-related diseases. Then, animal models of immune stress (IS) and immunosuppressive (IP) were selected to simulate the immune status of the above diseases. Meanwhile, psoralen, a main component derived from Psoralea corylifolia Linn. with definite hepatotoxicity, was selected as an experimental drug with highly similar molecular fingerprints to three idiosyncratic hepatotoxic drugs (nefazodone, trovafloxacin, and nimesulide) from the same DILI_PGS dataset. The animal experiment results found a single administration of psoralen could significantly induce liver injury in IS mice, while there was no obvious liver function change in IP mice by repeatedly administering the same dose of psoralen, and the potential mechanism of psoralen-induced liver injury in IS mice may be related to regulating the expression of the TNF-related pathway. In conclusion, this study constructed the DILI_PGS with high accuracy to predict the occurrence of DILI and preliminarily identified the characteristics of host factors inducing DILI.

Risk Assessment for Hepatobiliary Toxicity Liabilities in Drug Development

Risk assessment of hepatobiliary toxicities represents one of the greatest challenges and, more often than not, one of the most rewarding activities in which toxicologic pathologists can partake, and often times lead. This is in part because each liver toxicity picture is a bit different, informed by a broad range and diversity of relevant data, and also in part because the heavily relied upon animal models are imperfect regarding predictivity of hepatic effects in humans. Following identification and characterization of a hepatotoxicity hazard, typically in nonclinical toxicology studies, a holistic and integrated assessment of liver-relevant endpoints is conducted that typically incorporates ADME (absorption, distribution, metabolism, and excretion) information (ideally, including extensive transporter data, exposure margins, and possibly concentration of parent/metabolite at region of injury), target expression/function, in silico prediction data, in vitro hepatocyte data, liver/circulating biomarkers, and importantly, species specificity of any of these data. Of course, a thorough understanding, developed in close partnership with clinical colleagues, of the anticipated liver disease status of intended patient populations is paramount to hepatic risk assessment. This is particularly important since the likelihood of translatable determinant hepatic events observed in nonclinical models to occur in humans has been reasonably well established.

Drug-induced liver injury: Relation between the R ratio and histopathology

INTRODUCTION AND AIM

Drug-induced liver injury (DILI) is a diagnosis based on the ruling out of potential liver diseases and consolidated by establishing causality through the temporal relation between a potentially hepatotoxic substance and altered liver biochemistry. Incidence fluctuates greatly worldwide, with very few reports of causal agents of DILI in Colombia. A retrospective study on patients treated at the Centro de Estudios en Salud (CES), within the time frame of January 2015 and June 2020, was conducted to document the causal substances of DILI in patients with liver biopsy and to correlate the types of histologic patterns with the biochemical pattern of liver injury (R ratio).

RESULTS

Of the 254 adult patients with liver biopsy and no tumor etiology, 20 patients were identified as cases of DILI (7.87%). The two most frequently found causal substances were efavirenz, in three HIV-positive patients, and Moringa oleifera (moringa), in two patients. There was a statistically significant association between cholestatic patterns (p = 0.037) and mixed patterns (p = 0.031), in the comparison of the histopathologic categories and the R ratio.

CONCLUSION

To the best of our knowledge, there are no reports on DILI secondary to Moringa oleifera (moringa). The R ratio could be a useful tool, in relation to the histologic pattern of injury, in cases of mixed and cholestatic patterns.

The progression of chronicity and autoimmune hepatitis in recurrent drug-induced liver injury

BACKGROUND AND AIMS

Recurrent drug-induced liver injury (DILI) is not well documented. We retrospectively analysed the characteristics of patients who had a history of two separate DILI episodes due to different drugs.

METHODS

We collected data from 57 patients with recurrent DILI from 9582 confirmed DILI cases. Demographic, laboratory, and clinical data from both episodes were collected and analysed to determine the relationship between recurrent DILI, chronic DILI, and autoimmune hepatitis (AIH).

RESULTS

The incidence rate of recurrent DILI in our cohort was 0.59%. Most of the 57 patients with recurrent DILI were female (73.68%). The latency period of the initial episode was 30 days, whereas that of the second episode was 13 days (P = 0.003). The pattern of liver injury was not significantly different between episodes (P = 0.52). Laboratory indicators, such as alanine aminotransferase, aspartate transaminase, alkaline phosphatase, and total bilirubin, were significantly lower in the second episode than in the initial episode (P < 0.05). The incidence of chronic DILI was 43.86% during the initial episode and increased to 63.16% during the second episode. After the initial episode, 15 patients developed AIH during the second episode.

CONCLUSIONS

The latency period of recurrent DILI was gradually shortened. The clinical indices of liver injury tended to be less elevated during the second episode. Female post-menopausal patients with abnormal serum immunoglobulin G levels may be predisposed to AIH. The second DILI episode was more likely to have features of AIH.

Multifunctional Gold Nanoclusters for Effective Targeting, Near-Infrared Fluorescence Imaging, Diagnosis, and Treatment of Cancer Lymphatic Metastasis

Developing effective lymph-node (LN) targeting and imaging probes is crucial for the early detection and diagnosis of tumor metastasis to improve patient survival. Most current clinical LN imaging probes are based on small organic dyes (e.g., indocyanine green) or radioactive ^99mTc-complexes, which often suffer from limitations, such as rapid photobleaching, poor signal contrast, and potential biosafety issues. Moreover, these probes cannot easily incorporate therapeutic functions to realize beneficial theranostics without affecting their LN-targeting ability. Herein, we have developed dual-ligand-/multiligand-capped gold nanoclusters (GNCs) for specific targeting, near-infrared (NIR) fluorescence imaging, diagnosis, and treatment of LN cancer metastasis in in vivo mouse models. By optimizing the surface ligand coating, we have prepared Au₂₅(SR₁)_n(SR₂)_18-n (where SR₁ and SR₂ are different functional thiol ligands)-type GNCs, which display highly effective LN targeting, excellent stability and biocompatibility, and optimal body-retention time. Moreover, they can provide continuous NIR fluorescence imaging of LNs for >3 h from a single dose, making them well-suited for fluorescence-guided surgery. Importantly, we have further incorporated methotrexate, a chemotherapeutic drug, into the GNCs without affecting their LN-targeting ability. Consequently, they can significantly improve the efficiency of methotrexate delivery to target LNs, achieving excellent therapeutic efficacy with up to 4-fold lower hepatotoxicity. Thus, the GNCs are highly effective and safe theranostic nanomedicines against cancer lymphatic metastasis.

Ursolic acid alleviates tetrandrine-induced hepatotoxicity by competitively binding to the substrate-binding site of glutathione S-transferases

BACKGROUND

Tetrandrine (TET), a bisbenzylisoquinoline alkaloid isolated from Stephania tetrandra S. Moore, is the only approved medicine in China for silicosis. However, TET-induced hepatotoxicity has raised safety concerns. The underlying toxic targets and mechanism induced by TET remain unclear; there are no targeted detoxification strategies developed for TET-induced hepatotoxicity. Ursolic acid (UA), a pentacyclic triterpene with liver protective effects, may have detoxification effects on TET-induced hepatotoxicity.

PURPOSE

This study aims to explore toxic targets and mechanism of TET and present UA as a potential targeted therapy for alleviating TET-induced hepatotoxicity.

METHODS

A TET-induced liver-injury model was established to evaluate TET toxicity and the potential UA detoxification effect. Alkenyl-modified TET and UA probes were designed to identify potential liver targets. Pharmacological and molecular biology methods were used to explore the underlying toxicity/detoxification mechanism.

RESULTS

TET induced liver injury by covalently binding to the substrate-binding pocket (H-site) of glutathione S-transferases (GSTs) and inhibiting GST activity. The covalent binding led to toxic metabolite accumulation and caused redox imbalance and liver injury. UA protected the liver from TET-induced damage by competitively binding to the GST H-site.

CONCLUSION

The mechanism of TET-induced hepatotoxicity is related to irreversible binding with the GST H-site and GST-activity inhibition. UA, a natural antidote, competed with TET on H-site binding and reversed the redox imbalance. This study revealed the hepatotoxic mechanism of TET and provided a targeted detoxifying agent, UA, to alleviate hepatotoxicity caused by GST inhibition.

Protecting mitochondria via inhibiting VDAC1 oligomerization alleviates ferroptosis in acetaminophen-induced acute liver injury

Acetaminophen (APAP) overdose is a common cause of drug-induced liver injury (DILI). Ferroptosis has been recently implicated in APAP-induced liver injury (AILI). However, the functional role and underlying mechanisms of mitochondria in APAP-induced ferroptosis are unclear. In this study, the voltage-dependent anion channel (VDAC) oligomerization inhibitor VBIT-12 and ferroptosis inhibitors were injected via tail vein in APAP-injured mice. Targeted metabolomics and untargeted lipidomic analyses were utilized to explore underlying mechanisms of APAP-induced mitochondrial dysfunction and subsequent ferroptosis. As a result, APAP overdose led to characteristic changes generally observed in ferroptosis. The use of ferroptosis inhibitor ferrostatin-1 (or UAMC3203) and iron chelator deferoxamine further confirmed that ferroptosis was responsible for AILI. Mitochondrial dysfunction, which is associated with the tricarboxylic acid cycle and fatty acid β-oxidation suppression, may drive APAP-induced ferroptosis in hepatocytes. APAP overdose induced VDAC1 oligomerization in hepatocytes, and protecting mitochondria via VBIT-12 alleviated APAP-induced ferroptosis. Ceramide and cardiolipin levels were increased via UAMC3203 or VBIT-12 in APAP-induced ferroptosis in hepatocytes. Knockdown of Smpd1 and Taz expression responsible for ceramide and cardiolipin synthesis, respectively, aggravated APAP-induced mitochondrial dysfunction and ferroptosis in hepatocytes, whereas Taz overexpression protected against these processes. By immunohistochemical staining, we found that levels of 4-hydroxynonenal (4-HNE) protein adducts were increased in the liver biopsy samples of patients with DILI compared to that in those of patients with autoimmune liver disease, chronic viral hepatitis B, and non-alcoholic fatty liver disease (NAFLD). In summary, protecting mitochondria via inhibiting VDAC1 oligomerization attenuated hepatocyte ferroptosis by restoring ceramide and cardiolipin content in AILI.

[Drug-induced liver injury-significance of pathology]

Many different medical agents, herbal products, and dietary supplements can induce drug-induced liver injury (DILI) as a clinically relevant complication. DILI, which is direct toxic or idiosyncratic, can have a broad spectrum of clinical appearances from elevation of liver enzymes to acute liver failure. DILI is categorized clinically according to the pattern of serum parameters or pathologically according to the pattern of histomorphology. Histopathological patterns can be described as hepatitic, granulomatous, cholestatic, ductopenic, fibrotic, steatotic, steatohepatitic, and vascular. Correlation to the corresponding drug can be carried out with the corresponding databases (US National Library of Medicine, Liver Tox; www.ncbi.nlm.nih.gov/books/NBK547852/ ). Liver biopsy, in contrast to a clinical/serological diagnostic, has the advantage of an exact resolution with evidence of pathophysiology, activity, regeneration, chronification, and prognosis. Co-occurrence of underlying liver disease can be excluded or confirmed. Histological patterns of DILI are described and illustrated. A diagnostic algorithm for the interpretation of liver biopsies is provided.

Histologic pattern is better correlated with clinical outcomes than biochemical classification in patients with drug-induced liver injury

Histologically, drug-induced liver injury could be classified into acute hepatitis, chronic hepatitis, acute cholestasis, chronic cholestasis, and cholestatic hepatitis. The correlation between these histologic patterns and long-term clinical outcomes has not been well established. Therefore, we conducted a retrospective cohort study to investigate the association of histologic patterns and long-term clinical outcomes defined as biochemical normalization, persistent abnormal liver biochemistry or death at designated time points. In this study, biochemical classification was determined by R-values; histologic injury pattern was determined by morphological features. Predictive ability of clinical outcomes by these two classifications was assessed using Receiver Operating Characteristic Curves. Logistic regression was performed to identify histologic factors associated with outcomes. Totally, 88 patients with drug-induced liver injury were included for final analysis. Biochemical and histologic classification were consistent in 50 (57%) cases. 53 (60%) cases showed biochemical normalization within 6 months, and a further 11 (13%), 16 (18%), and 6 (7%) cases within 1, 2, and 3 years, respectively. Compared with biochemical classification, histologic injury pattern had better predictive ability for abnormal biochemistry at 6 months (Areas under Receiver Operating Characteristic Curves 0.92 versus 0.60, P < 0.001) and 1 year (Areas under Receiver Operating Characteristic Curves 0.94 versus 0.69, P < 0.001). Interlobular bile duct loss in >25% portal areas was independently associated with abnormal biochemistry at 6 months, 1 year, and 2 years. In conclusion, histologic injury pattern is better correlated with clinical outcome at 6 months and 1 year than biochemical classification. Moderate bile duct loss is an important histologic feature associated with persistent biochemical abnormality at 6 months, 1 year, and 2 years.

Novel biomarkers for potential risk stratification of drug induced liver injury (DILI): A narrative perspective on current trends

BACKGROUND

Drug induced liver injury (DILI) is an increasing cause of acute liver injury especially with increasing need for pharmacotherapy of widening comorbidities amongst our ever-aging population. Uncertainty however remains regarding both acceptable and widely agreeable diagnostic algorithms as well a clear understanding of mechanistic insights that most accurately underpins it. In this review, we have explored the potential role of emerging novel markers of DILI and how they could possibly be integrated into clinical care of patients.

METHODS

We explored PUBMED and all other relevant databases for scientific studies that explored potential utility of novel biomarkers of DILI, and subsequently carried out a narrative synthesis of this data. As this is a narrative review with no recourse to patient identifiable information, no ethics committee's approval was sought or required.

RESULTS

Novel biomarkers such as microRNA-122 (miR-122) profiles, high mobility group box-1 (HMGB1), glutamate dehydrogenase (GLDH), and cytokeratin-18 (K-18), amongst others do have the potential for reducing diagnostic uncertainties associated with DILI.

CONCLUSION

With the increasing validation of some of the novel liver biomarkers such as K-18, mir-122, HMGB-1, and GLDH, there is the potential for improvement in the diagnostic uncertainty commonly associated with cases of DILI.

Mechanisms of Hepatic Cholestatic Drug Injury

Drug-induced cholestasis represents a form of drug-induced liver disease that can lead to severe impairment of liver function. Numerous drugs have been shown to cause cholestasis and consequently bile duct toxicity. However, there is still lack of therapeutic tools that can prevent progression to advanced stages of liver injury. This review focuses on the various pathological mechanisms by which drugs express their hepatotoxic effects, as well as consequences of increased bile acid and toxin accumulation in the hepatocytes.

The Beneficial Roles of SIRT1 in Drug-Induced Liver Injury

Drug-induced liver injury (DILI) is a major cause of acute liver failure (ALF) as a result of accumulated drugs in the human body metabolized into toxic agents and helps generate heavy oxidative stress, inflammation, and apoptosis, which induces necrosis in hepatocytes and ultimately damages the liver. Sirtuin 1 (SIRT1) is said to have multiple vital roles in cell proliferation, aging, and antistress systems of the human body. The levels of SIRT1 and its activation precisely modulate its critical role in the interaction between multiple step procedures of DILI. The nuclear factor kappa-light-chain-enhancer of activated B cell- (NF-κB-) mediated inflammation signaling pathway, reactive oxygen species (ROS), DNA damage, mitochondrial membrane potential collapse, and endoplasmic reticulum (ER) stress also contribute to aggravate DILI. Apoptosis is regarded as the terminal reaction followed by multiple signaling cascades including caspases, p53, and mitochondrial dysfunction which have been said to contribute in DILI. The SIRT1 activator is regarded as a potential candidate for DILI, because the former could inhibit signaling of p53, NF-κB, and ER stress. On the other hand, overexpression of SIRT1 also enhances the activation of antioxidant responses via Kelch-like ECH-associated protein 1- (Keap1-) nuclear factor- (erythroid-derived 2-) like 2 (Nrf2) signaling. The current manuscript will highlight the mechanism of DILI and the interaction of SIRT1 with various cytoplasmic factors leading to DILI along with the summary of potent SIRT1 agonists.