Global Epidemiology of Drug-Induced Liver Injury (DILI)

The Epidemiology of Newly Recognized Causes of Drug-Induced Liver Injury: An Update

The incidence and prevalence of drug-induced liver injury appear to be increasing globally, for example, with the introduction of checkpoint inhibitors. Several reviews have been published in the last decade on the epidemiology of DILI, both among hospitalized patients and in the general population, as well as from retrospective and prospective studies on DILI. Most of these reviews have not focused on newly recognized agents that have recently changed the landscape of DILI. Apart from liver injury associated with antibiotics, oncological agents, particularly checkpoint inhibitors, are increasingly being recognized as causing liver injury. The type of liver injury associated with these agents is not idiosyncratic but rather an indirect type of injury. Furthermore, recently, COVID-19 vaccines and green tea extract have been found to lead to liver injury. Checkpoint inhibitors have revolutionized the treatment of many malignancies, such as malignant melanoma, lung cancer, and renal cancer. Via the activation of T cells, they can increase immune activity against malignant cells, but at the same time, they can decrease immune tolerance and therefore lead to immune-related adverse effects in many organs. The most common adverse effect in clinical practice is liver injury. A recent prospective study demonstrated an 8% frequency of DILI due to the use of checkpoint inhibitors among patients with malignant melanoma and renal cancer. This rate is much higher than observed with drugs, leading to idiosyncratic liver injury. Shortly after the implementation of the worldwide vaccination program against COVID-19, several case reports were published on suspected vaccination-induced autoimmune-like hepatitis occurring shortly after the vaccination. At first, these reports were met with skepticism, but currently, around 100 reports have been published, and cases of positive recurrence have been reported. The clinical, biochemical, immunological, and histological features are indistinguishable from classic autoimmune hepatitis (AIH). These reactions are very similar to drug-induced autoimmune-like hepatitis (DI-ALH) due to drugs such as nitrofurantoin, minocycline, and infliximab, which do not relapse after a short course of corticosteroids, which is the general rule in classic autoimmune hepatitis (AIH). Green tea extract has been found to be a well-documented cause of acute hepatocellular liver injury with jaundice. A strong HLA association has been reported, showing a high prevalence of HLA-B*35:01 among patients suffering from green tea-induced liver injury. Overall, 3% of patients recruited in the DILIN study were supplemented with green tea extract as one of the ingredients. In a prospective population-based study from Iceland, green tea was implicated in approximately 8% of patients with DILI.

Nanobody-based pannexin1 channel inhibitors reduce inflammation in acute liver injury

BACKGROUND

The opening of pannexin1 channels is considered as a key event in inflammation. Pannexin1 channel-mediated release of adenosine triphosphate triggers inflammasome signaling and activation of immune cells. By doing so, pannexin1 channels play an important role in several inflammatory diseases. Although pannexin1 channel inhibition could represent a novel clinical strategy for treatment of inflammatory disorders, therapeutic pannexin1 channel targeting is impeded by the lack of specific, potent and/or in vivo-applicable inhibitors. The goal of this study is to generate nanobody-based inhibitors of pannexin1 channels.

RESULTS

Pannexin1-targeting nanobodies were developed as potential new pannexin1 channel inhibitors. We identified 3 cross-reactive nanobodies that showed affinity for both murine and human pannexin1 proteins. Flow cytometry experiments revealed binding capacities in the nanomolar range. Moreover, the pannexin1-targeting nanobodies were found to block pannexin1 channel-mediated release of adenosine triphosphate. The pannexin1-targeting nanobodies were also demonstrated to display anti-inflammatory effects in vitro through reduction of interleukin 1 beta amounts. This anti-inflammatory outcome was reproduced in vivo using a human-relevant mouse model of acute liver disease relying on acetaminophen overdosing. More specifically, the pannexin1-targeting nanobodies lowered serum levels of inflammatory cytokines and diminished liver damage. These effects were linked with alteration of the expression of several NLRP3 inflammasome components.

CONCLUSIONS

This study introduced for the first time specific, potent and in vivo-applicable nanobody-based inhibitors of pannexin1 channels. As demonstrated for the case of liver disease, the pannexin1-targeting nanobodies hold great promise as anti-inflammatory agents, yet this should be further tested for extrahepatic inflammatory disorders. Moreover, the pannexin1-targeting nanobodies represent novel tools for fundamental research regarding the role of pannexin1 channels in pathological and physiological processes.

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.

Prospects of Probiotic Adjuvant Drugs in Clinical Treatment

In modern society, where new diseases and viruses are constantly emerging, drugs are still the most important means of resistance. However, adverse effects and diminished efficacy remain the leading cause of treatment failure and a major determinant of impaired health-related quality of life for patients. Clinical studies have shown that the disturbance of the gut microbial structure plays a crucial role in the toxic and side effects of drugs. It is well known that probiotics have the ability to maintain the balance of intestinal microecology, which implies their potential as an adjunct to prevent and alleviate the adverse reactions of drugs and to make medicines play a better role. In addition, in the past decade, probiotics have been found to have excellent prevention and alleviation effects in drug toxicity side effects, such as liver injury. In this review, we summarize the development history of probiotics, discuss the impact on drug side effects of probiotics, and propose the underlying mechanisms. Probiotics will be a new star in the world of complementary medicine.

Biological Role of Pazopanib and Sunitinib Aldehyde Derivatives in Drug-Induced Liver Injury

Tyrosine kinase inhibitors pazopanib and sunitinib are both used to treat advanced renal cell carcinoma but expose patients to an increased risk of hepatotoxicity. We have previously identified two aldehyde derivatives for pazopanib and sunitinib (P-CHO and S-CHO, respectively) in liver microsomes. In this study, we aimed to decipher their role in hepatotoxicity by treating HepG2 and HepaRG hepatic cell lines with these derivatives and evaluating cell viability, mitochondrial dysfunction, and oxidative stress accumulation. Additionally, plasma concentrations of P-CHO were assessed in a cohort of patients treated with pazopanib. Results showed that S-CHO slightly decreased the viability of HepG2, but to a lesser extent than sunitinib, and affected the maximal respiratory capacity of the mitochondrial chain. P-CHO decreased viability and ATP production in HepG2. Traces of P-CHO were detected in the plasma of patients treated with pazopanib. Overall, these results showed that P-CHO and S-CHO affect hepatocyte integrity and could be involved in the pazopanib and sunitinib hepatotoxicity.

Combination Treatment of Omega-3 Fatty Acids and Vitamin C Exhibited Promising Therapeutic Effect against Oxidative Impairment of the Liver in Methotrexate-Intoxicated Mice

Drug-induced liver injury (DILI) is the main cause of liver damage mediated by the excretion of toxic active drug metabolites. Omega-3 fatty acids and vitamin C have potent antioxidant, anti-inflammatory, and antiapoptotic effects that could offer protection against oxidative stress and liver damage. This study evaluated the hepatoprotective effect of omega-3 and vitamin C alone as well as in a combined form in methotrexate- (MTX-) induced acute liver injury in mice. Male ICR mice of seven groups (7 mice per group) were used. Groups 1 (control group) and 2 (MTX) received 0.9% saline/day (po) for 9 days. Groups 3 and 4 received 100 and 200 mg/kg bw/day omega-3 (po), respectively, for 9 days. Groups 5 and 6 received 100 and 200 mg/kg bw/day vitamin C (po), respectively, for 9 days, while group 7 received omega-3 (100 mg/kg bw/day) and vitamin C (100 mg/kg bw/day) (po) for 9 days. All animals in groups 2 to 7 received 20 mg/kg/day MTX (I.P.) once on the 10th day. Our results revealed that MTX significantly induced the elevation of transaminases, alkaline phosphates (ALP), lactate dehydrogenase (LDH), and malonaldehyde (MDA) while depleting the levels of superoxide dismutase (SOD) and glutathione (GSH) when compared to the control group. Treatment with omega-3 fatty acids or vitamin C significantly attenuated the antioxidants and biochemical alterations in a dose-independent manner. Our molecular docking study of ligand-receptor interaction revealed that both ascorbic acid and omega-3 docked well to the binding cavity of LDH with high binding affinities of -5.20 and -4.50 kcal/mol, respectively. The histopathological features were also improved by treatment with omega-3 and vitamin C. The combined form of omega-3 and vitamin C showed a remarkable improvement in the liver enzymes, oxidative stress biomarkers, and the histopathological architecture of the mice. Conclusively, the combination of omega-3 and vitamin C demonstrated a synergistic therapeutic effect against MTX-intoxicated mice, hence representing a potential novel strategy for the management of drug-induced liver disorders.

Drug-induced Fatty Liver Disease: Pathogenesis and Treatment

Metabolic dysfunction-associated fatty liver disease (commonly known as MAFLD) impacts global health in epidemic proportions, and the resulting morbidity, mortality and economic burden is enormous. While much attention has been given to metabolic syndrome and obesity as offending factors, a growing incidence of polypharmacy, especially in the elderly, has greatly increased the risk of drug-induced liver injury (DILI) in general, and drug-induced fatty liver disease (DIFLD) in particular. This review focuses on the contribution of DIFLD to DILI in terms of epidemiology, pathophysiology, the most common drugs associated with DIFLD, and treatment strategies.

The human hepatocyte TXG-MAPr: gene co-expression network modules to support mechanism-based risk assessment

Mechanism-based risk assessment is urged to advance and fully permeate into current safety assessment practices, possibly at early phases of drug safety testing. Toxicogenomics is a promising source of mechanisms-revealing data, but interpretative analysis tools specific for the testing systems (e.g. hepatocytes) are lacking. In this study, we present the TXG-MAPr webtool (available at https://txg-mapr.eu/WGCNA_PHH/TGGATEs_PHH/ ), an R-Shiny-based implementation of weighted gene co-expression network analysis (WGCNA) obtained from the Primary Human Hepatocytes (PHH) TG-GATEs dataset. The 398 gene co-expression networks (modules) were annotated with functional information (pathway enrichment, transcription factor) to reveal their mechanistic interpretation. Several well-known stress response pathways were captured in the modules, were perturbed by specific stressors and showed preservation in rat systems (rat primary hepatocytes and rat in vivo liver), with the exception of DNA damage and oxidative stress responses. A subset of 87 well-annotated and preserved modules was used to evaluate mechanisms of toxicity of endoplasmic reticulum (ER) stress and oxidative stress inducers, including cyclosporine A, tunicamycin and acetaminophen. In addition, module responses can be calculated from external datasets obtained with different hepatocyte cells and platforms, including targeted RNA-seq data, therefore, imputing biological responses from a limited gene set. As another application, donors' sensitivity towards tunicamycin was investigated with the TXG-MAPr, identifying higher basal level of intrinsic immune response in donors with pre-existing liver pathology. In conclusion, we demonstrated that gene co-expression analysis coupled to an interactive visualization environment, the TXG-MAPr, is a promising approach to achieve mechanistic relevant, cross-species and cross-platform evaluation of toxicogenomic data.