Novel biomarkers for drug-induced liver injury

Sensitivity and stability of Balb/c, C57BL/6J, and ICR mice to the acute liver injury induced by concanavalin A

Autoimmune hepatitis (AIH) is an autoimmune disease mediated by abnormal autoimmune. The pathogenesis and pathological manifestation of immune-mediated liver injury, induced by concanavalin A (ConA) in mice, closely parallel those observed in human AIH. However, the sensitivity and stability of mice to ConA vary depending on the strain and sex of the mice. Therefore, this study aimed to compare the sensitivity and stability of Balb/c, C57BL/6J, and ICR mice to ConA-induced acute liver injury. In this study, the mice in ConA group were injected with ConA (15 mg/kg·bw) via tail vein. After 8 h, the blood, liver, and spleen were collected for subsequent analysis. The liver index of Balb/c mice was increased (P < 0.05). Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) levels of male C57BL/6J mice in ConA-treated group were the highest among the three strains of mice, followed by female Balb/c mice (P < 0.05). After ConA challenge, ICR, Balb/c, and C57BL/6J mice (both male and female) appeared markedly inflammatory cell infiltration and hepatocyte necrosis. Furthermore, hemorrhagic necrosis is more severe in females than in males. Lastly, male C57BL/6J and female Balb/c mice had the lowest coefficient of variation in serum ALT, AST, and LDH activities, while female Balb/c mice had the minimum coefficient of variation of the liver index, suggesting that they have good stability to ConA. Altogether, our study found that Balb/c female and C57BL/6J male mice have high sensitivity and good stability to ConA challenge, which were suitable for mimicking the pathology of AIH in humans.

HiSNAP trial-a multicentre, randomised, open-label, blinded end point, safety and efficacy trial of conventional (300 mg/kg) versus higher doses of acetylcysteine (450 mg/kg and 600 mg/kg) in patients with paracetamol overdose in the UK: study protocol

INTRODUCTION

In overdose, a larger proportion of paracetamol (acetaminophen) is converted in the liver to the toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI). Glutathione (GSH) is the endogenous antioxidant that protects cells from NAPQI-induced injury. In overdose, GSH stores may become depleted, leaving NAPQI free to produce liver damage. N-Acetylcysteine (NAC) helps prevent paracetamol toxicity by replenishing liver GSH. This protective effect of NAC produces specific metabolites in the circulation. Currently, regardless of the paracetamol dose ingested, patients in the UK receive a dose of NAC based only on their weight. Basic pharmacology, mathematical modelling and observational studies suggest that this dose may be insufficient in some patients (particularly those taking a large overdose).

METHODS AND ANALYSIS

A multicentre trial, taking place across several hospitals in Scotland, UK, within Emergency Departments and Acute Medical Units. Recruitment commenced on 19 February 2024 and is anticipated to run for approximately 2 years. This is a three-group dose-finding trial, in which participants are assigned in a 1:1:1 ratio to either Standard NAC (300 mg/kg) or higher doses of 450 mg/kg (Group 1) and 600 mg/kg (Group 2). The primary outcome is the proportion of paracetamol metabolites in the circulation that are directly produced by GSH/NAC detoxification of NAPQI. A higher proportion of these metabolites will indicate that the additional NAC is reducing the amount of toxic paracetamol metabolites in the body. The study will first test the primary outcome on the HiSNAP Group 2 against Standard NAC; only if that is significant will HiSNAP Group 1 be tested against Standard NAC.

ETHICS AND DISSEMINATION

The HiSNAP trial has been approved by the East Midlands (Derby) Research Ethics Committee (reference 23/EM/0129), NHS Lothian Research and Development Department, and the MHRA. Results will be disseminated by peer-reviewed publication, conferences and linked on isrctn.com.

TRIAL REGISTRATION NUMBER

ISRCTN17516192.

The emerging role of alternatively activated macrophages to treat acute liver injury

Acute liver injury (ALI) has a clear requirement for novel therapies. One emerging option is the use of alternatively activated macrophages (AAMs); a distinct subtype of macrophage with a role in liver injury control and repair. In this comprehensive review, we provide an overview of the current limited options for ALI, and the potential advantages offered by AAMs. We describe the evidence supporting their use from in vitro studies, pre-clinical animal studies, and human clinical trials. We suggest why the first evidence for the clinical use of AAMs is likely to be found in acetaminophen toxicity, and discuss the specific evidence for AAM use in this population, as well as potential applications for AAMs in other patient populations. The key domains by which the performance of AAMs for the treatment of ALI will be assessed are identified, and remaining challenges to the successful delivery of AAMs to clinic are explored.

Macrophage Therapy for Acute Liver Injury (MAIL): a study protocol for a phase 1 randomised, open-label, dose-escalation study to evaluate safety, tolerability and activity of allogeneic alternatively activated macrophages in patients with paracetamol-induced acute liver injury in the UK

INTRODUCTION

Acute liver failure (ALF) has no effective treatment other than liver transplantation and is commonly caused by paracetamol overdose. New treatments are needed to treat and prevent ALF. Alternatively-activated macrophages (AAMs) can promote resolution of liver necrosis and stimulate hepatocyte proliferation. Using AAMs in unscheduled care requires the use of an allogeneic product. A clinical trial is needed to determine the safety and tolerability of allogeneic AAMs.

METHODS AND ANALYSIS

A single-centre, open-label, dose-escalation, phase 1 randomised trial to determine whether there is dose-limiting toxicity of AAMs in patients with paracetamol-induced acute liver injury. Randomisation will occur at higher doses. Between 17 and 30 patients will receive treatment, subject to dose-limiting toxicity and an adaptive trial design which aims to reduce the risk of allocation bias through blinding and randomisation.

ETHICS AND DISSEMINATION

The trial will be conducted according to the ethical principles of the Declaration of Helsinki 2013 and has been approved by North East-York Research Ethics Committee (reference 23/NE/0019), National Health Service Lothian Research and Development department, and the UK Medicines and Healthcare products Regulatory Agency. When the trial concludes, results will be shared by presentation and publication.

TRIAL REGISTRATION NUMBER

ISRCTN12637839.

Serum Levels of miR-122-5p and miR-125a-5p Predict Hepatotoxicity Occurrence in Patients Undergoing Autologous Hematopoietic Stem Cell Transplantation

Hepatic complications are an acknowledged cause of mortality and morbidity among patients undergoing hematopoietic stem cell transplantation. In this study, we aimed to evaluate the potential role in the prediction of liver injury of five selected microRNAs (miRNAs)-miR-122-5p, miR-122-3p, miR-15b-5p, miR-99b-5p, and miR-125a-5p-in the setting of autologous hematopoietic stem cell transplantation (ASCT). A total of 66 patients were included in the study: 50 patients (75.8%) with multiple myeloma (MM) and 16 (24.2%) with lymphoma. Blood samples were collected after the administration of the conditioning regimen, on the day of transplant (day 0). The expression levels of selected miRNAs were quantified by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) using the miRCURY LNA miRNA Custom PCR Panels (QIAGEN). In a multivariate logistic regression analysis adjusted for age, sex, and the administered conditioning regimen, two miRNAs, hsa-miR-122-5p (odds ratio, OR 2.10, 95% confidence interval, CI: 1.29-3.42, p = 0.0029) and hsa-miR-125a-5p (OR 0.27, 95% CI: 0.11-0.71, p = 0.0079), were independent for hepatic toxicity occurrence during the 14 days after transplant. Our model in 10-fold cross-validation preserved its diagnostic potential with a receiver operating characteristics area under the curve (ROC AUC) of 0.75, 95% CI: 0.63-0.88 and at optimal cut-off reached 72.0% sensitivity and 74.4% specificity. An elevated serum level of miR-122-5p and decreased level of miR-125a-5p on day 0 are independent risk factors for hepatotoxicity in ASCT recipients, showing promise in accurately predicting post-ASCT complications. Identifying patients susceptible to complications has the potential to reduce procedure costs and optimize the selection of inpatient or outpatient procedures.

Fifty years of paracetamol (acetaminophen) poisoning: the development of risk assessment and treatment 1973-2023 with particular focus on contributions published from Edinburgh and Denver

INTRODUCTION

Fifty years ago, basic scientific studies and the availability of assay methods made the assessment of risk in paracetamol (acetaminophen) poisoning possible. The use of the antidote acetylcysteine linked to new methods of risk assessment transformed the treatment of this poisoning. This review will describe the way in which risk assessment and treatments have developed over the last 50 years and highlight the remaining areas of uncertainty.

METHODS

A search of PubMed and its subsidiary databases revealed 1,166 references published in the period 1963-2023 using the combined terms "paracetamol", "poisoning", and "acetylcysteine". Focused searches then identified 170 papers dealing with risk assessment of paracetamol poisoning, 141 with adverse reactions to acetylcysteine and 114 describing different acetylcysteine regimens. To manage the extensive literature, we focused mainly on contributions made by the authors during their time in Edinburgh and Denver.

DOSE AND CONCENTRATION RESPONSE

The key relationship between paracetamol dose and toxicity risk was established in 1971 and led to the development of the Rumack-Matthew nomogram from data collected in Edinburgh.

MECHANISMS OF TOXICITY

A series of papers on the mechanisms of toxicity were published in 1973, and these showed that paracetamol hepatotoxicity was caused by the formation of a toxic intermediate epoxide metabolite normally detoxified by glutathione but which, in excess, was bound covalently to hepatic enzymes and proteins. An understanding of the relationship between the rate of paracetamol metabolism, paracetamol concentration, and toxic hazard in humans soon followed.

ANTIDOTE DEVELOPMENT AND EFFICACY IN PATIENTS

These discoveries were followed by the testing of a range of sulfhydryl-donors in animals and "at risk" patients. Acetylcysteine was developed as the lead intravenous antidote in the United Kingdom. The license holder in the United States refused to make an intravenous formulation. Thus, oral acetylcysteine became the antidote trialed in the United States National Multicenter Study. Intravenous acetylcysteine regimens used initially in the United Kingdom and subsequently in the United States used loading doses of 150 mg/kg over 15 minutes or one hour, 50 mg/kg over four hours, and 100 mg/kg over 16 hours. These regimens were associated with adverse drug reactions (nausea, vomiting and anaphylactoid reactions) and hence, treatment interruption. Newer dosing regimens now give loading doses more slowly. One, the Scottish and Newcastle Anti-emetic Pretreatment protocol, using an acetylcysteine regimen of 100 mg/kg over two hours followed by 200 mg/kg over 10 hours, has been widely adopted in the United Kingdom. A cohort comparison study suggests this regimen has comparable efficacy to standard regimens and offers opportunities for selective higher acetylcysteine dosing.

RISK ASSESSMENT AT PRESENTATION

No dose-ranging studies with acetylcysteine were done, and no placebo-controlled studies were performed. Thus, there is uncertainty regarding the optimal dose of acetylcysteine, particularly in patients ingesting very large overdoses of paracetamol. The choice of intervention concentration on the Rumack-Matthew nomogram has important consequences for the proportion of patients treated. The United States National Multicenter Study used a "treatment" line starting at 150 mg/L (992 µmol/L) at 4 hours post overdose, extending to 24 hours with a half-life of 4 hours, now standard there, and subsequently adopted in Australia and New Zealand. In the United Kingdom, the treatment line was initially 200 mg/L (1,323 µmol/L) at 4 hours (the Rumack-Matthew "risk" line). In 2012, the United Kingdom Medicines and Healthcare products Regulatory Agency lowered the treatment line to 100 mg/L (662 µmol/L) at 4 hours for all patients, increasing the number of patients admitted and treated at a high cost. Risk assessment is a key issue for ongoing study, particularly following the development of potential new antidotes that may act in those at greatest risk. The development of biomarkers to assess risk is ongoing but has yet to reach clinical trials.

CONCLUSION

Even after 50 years, there are still areas of uncertainty. These include appropriate acetylcysteine doses in patients who ingest different paracetamol doses or multiple (staggered) ingestions, early identification of at-risk patients, and optimal treatment of late presenters.