Exacerbated liver injury of antithyroid drugs in endotoxin-treated mice

Preclinical models of idiosyncratic drug-induced liver injury (iDILI): Moving towards prediction

Idiosyncratic drug-induced liver injury (iDILI) encompasses the unexpected harms that prescription and non-prescription drugs, herbal and dietary supplements can cause to the liver. iDILI remains a major public health problem and a major cause of drug attrition. Given the lack of biomarkers for iDILI prediction, diagnosis and prognosis, searching new models to predict and study mechanisms of iDILI is necessary. One of the major limitations of iDILI preclinical assessment has been the lack of correlation between the markers of hepatotoxicity in animal toxicological studies and clinically significant iDILI. Thus, major advances in the understanding of iDILI susceptibility and pathogenesis have come from the study of well-phenotyped iDILI patients. However, there are many gaps for explaining all the complexity of iDILI susceptibility and mechanisms. Therefore, there is a need to optimize preclinical human in vitro models to reduce the risk of iDILI during drug development. Here, the current experimental models and the future directions in iDILI modelling are thoroughly discussed, focusing on the human cellular models available to study the pathophysiological mechanisms of the disease and the most used in vivo animal iDILI models. We also comment about in silico approaches and the increasing relevance of patient-derived cellular models.

Methimazole Treatment and Risk of Acute Pancreatitis: A Population-based Cohort Study

CONTEXT

A warning has been recently issued by the European Medicine Agency (EMA) regarding a potential increased risk of acute pancreatitis (AP) in methimazole (MMI) users.

OBJECTIVE

To investigate the association between MMI and the diagnosis of AP in a population-based study.

MATERIALS AND METHODS

A retrospective analysis of administrative health databases was conducted (2013-2018). Relevant data were obtained from: (1) inhabitants registry, (2) hospital discharge records (ICD-9-CM 577.0), and (3) drug claims registry (ATC H03BB02). We evaluated AP risk in MMI users in 18 months of treatment, stratifying results by trimester. Poisson regression was used to estimate the age- and sex-adjusted rate ratios (RR), and the relative 95% confidence intervals (CI), comparing rates of AP between MMI users and nonusers. The absolute risk of AP in MMI users was also calculated.

RESULTS

A total of 23 087 new users of MMI were identified. Among them, 61 hospitalizations occurred during the study period. An increase in AP risk was evident during the first 3 trimesters of therapy (RR 3.40 [95% CI: 2.12-5.48]; RR 2.40 [95% CI: 1.36-4.23]; RR 2.80 [95% CI: 1.66-4.73]), but disappeared thereafter. The AP absolute risk in MMI users during the first 18 months of treatment was less than 0.4% in all sex and age classes.

CONCLUSIONS

Our results support the EMA warning, suggesting an increased risk of AP associated with MMI use. However, such an increase seems limited to the first months of MMI treatment. Moreover, in absolute terms, the probability of AP is low among patients, well below 1%.

Acute Drug-Induced Cholestatic Syndrome in Basedow Graves’ Disease

Introduction: Graves’ disease (GD), an autoimmune disorder caused by high levels of auto-antibodies against the thyroid-stimulating hormone receptor, is considered the most common cause of thyrotoxicosis, characterized by features such as goiter, ophthalmopathy and dermopathy. In our country, the administration of antithyroid drugs (ATD) is the first line of treatment in this disease. Side effects are rare but some of them, such as agranulocytosis or liver damage, may become serious.

Case presentation: We report the case of a 20-year-old female patient who was diagnosed with GD after being previously diagnosed with viral hepatitis A. Treatment was initiated with methimazole 30 mg/day, and three weeks later she developed intense hepatic cytolysis and cholestatic syndrome, therefore the ATD was stopped. A suspicion of autoimmune liver disease was raised, and a liver biopsy was performed in order to establish the diagnosis. The next therapeutic option for hyperthyroidism was radioactive iodine (RAI). Three months following RAI, the patient presented severe hypothyroidism, thereupon treatment with levothyroxine was initiated.

Conclusions: Although severe acute liver injury is rare, mild liver dysfunction is quite common in patients with GD. The overproduction of thyroid hormones, or the treatment with ATD through immune mediated processes or drug reactions, represent possible mechanisms responsible for liver damage.

What have we learned from animal models of idiosyncratic, drug-induced liver injury?

INTRODUCTION

Idiosyncratic, drug-induced liver injury (IDILI) continues to plague patients and restrict the use of drugs that are pharmacologically effective. Mechanisms of IDILI are incompletely understood, and a better understanding would reduce speculation and could help to identify safer drug candidates preclinically. Animal models have the potential to enhance knowledge of mechanisms of IDILI.

AREAS COVERED

Numerous hypotheses have emerged to explain IDILI pathogenesis, many of which center on the roles of the innate and/or adaptive immune systems. Animal models based on these hypotheses are reviewed in the context of their contributions to understanding of IDILI and their limitations.

EXPERT OPINION

Animal models of IDILI based on an activated adaptive immune system have to date failed to reproduce major liver injury that is of most concern clinically. The only models that have so far resulted in pronounced liver injury are based on the multiple determinant hypothesis or the inflammatory stress hypothesis. The liver pathogenesis in IDILI animal models involves various leukocytes and immune mediators such as cytokines. Insights from animal models are changing the way we view IDILI pathogenesis and are leading to better approaches to preclinical prediction of IDILI potential of new drug candidates.

Research Progress on the Animal Models of Drug-Induced Liver Injury: Current Status and Further Perspectives

Drug-induced liver injury (DILI) is a major concern in clinical studies as well as in postmarketing surveillance. It is necessary to establish an animal model of DILI for thorough investigation of mechanisms of DILI and searching for protective medications. This article reviews the current status and future perspective on establishment of DILI models based on different hepatotoxic drugs, as well as the underlying mechanisms of liver function damage induced by specific medicine. Therefore, information from this article can help researchers make a suitable selection of animal models for further study.