Drug-induced Tissue Injury Research Articles

Universal Accessible Biomarkers of Drug-Induced Tissue Injury and Systemic Inflammation in Rat: Performance Assessment of TIMP-1, A2M, AGP, NGAL, and Albumin.

The ability to monitor for general drug-induced tissue injury (DITI) or systemic inflammation in any tissue using blood-based accessible biomarkers would provide a valuable tool in early exploratory animal studies to understand potential drug liabilities. Here we describe the evaluation of 4 biomarkers of tissue remodeling and inflammation (α2-macroglobulin [A2M], α1-acid glycoprotein [AGP], neutrophil gelatinase-associated lipocalin [NGAL], and tissue inhibitor of metalloproteinases [TIMP-1]) as well as the traditional serum parameter albumin as potential blood-based biomarkers of DITI and systemic inflammatory response (SIR). Biomarker performance was assessed in 51 short-term rat in vivo studies with various end-organ toxicities or SIR and receiver operating characteristic curves were generated to compare relative performances. All 4 biomarkers performed well in their ability to detect DITI and SIR with an area under the curve (AUC) of 0.82-0.78, however TIMP-1 achieved the best sensitivity (at 95% specificity) of 61%; AGP, NGAL, and A2M sensitivity was 51%-52%. AUC for albumin was 0.72 with sensitivity of 39%. A2M was the best performer in studies with only SIR (AUC 0.91). In the subset of studies with drug-induced vascular injury, TIMP-1 performed best with an AUC of 0.96. Poor performance of all tested biomarkers was observed in samples with CNS toxicity. In summary, TIMP-1, A2M, AGP, and NGAL demonstrated performance as sensitive accessible biomarkers of DITI and SIR, supporting their potential application as universal accessible tissue toxicity biomarkers to quickly identify dose levels associated with drug-induced injury in early exploratory rat safety and other studies.

A reactive oxygen species-responsive antioxidant nanotherapy for the treatment of drug-induced tissue and organ injury.

Drug-induced tissue injury has become a growing public health problem. Gastrointestinal injury and liver dysfunction are the most common side effects related to drug therapies, resulting in high morbidity and mortality in recent years. The overproduction of reactive oxygen species (ROS) is critically involved in the pathogenesis of drug-induced tissue injury. Consequently, antioxidant therapy represents a very promising strategy for the treatment of drug-induced tissue injury. Herein, a multifunctional antioxidant nanotherapy (TON) is engineered from a cyclodextrin-derived ROS-responsive material and a radical scavenger tempol, and is capable of eliminating a broad spectrum of ROS. After oral administration, TON can passively accumulate in the inflamed gastrointestinal tissues in mice with indomethacin-induced gastrointestinal injury. Correspondingly, TON shows superior efficacy in two representative murine models of indomethacin-induced gastrointestinal injury and acetaminophen-induced hepatic injury via attenuating oxidative stress and mitigating inflammatory responses. Additionally, preliminary in vitro and in vivo experiments demonstrate the good safety profile of TON. Consequently, the ROS-responsive antioxidant nanotherapy TON is promising for the treatment of drug-induced tissue and organ injury.

Stem cell-based in vitro models: state-of-the-art tools to predict drug-induced tissue injury in humans

Stem cell-based in vitro models: state-of-the-art tools to predict drug-induced tissue injury in humans

Accessible miRNAs as Novel Toxicity Biomarkers.

Novel tissue injury biomarkers have recently been identified that outperform or add value to the conventional safety biomarkers. These novel biomarkers have enhanced sensitivity and/or specificity in monitoring drug-induced tissue injury in a variety of tissues, included liver, kidney, and skeletal muscle. Among these novel biomarkers, microRNAs (miRNAs) are one type in particular that have received much attention in recent years. These microRNAs are short, endogenous noncoding nucleic acids that are involved in modulation and regulation of mRNA transcripts. Other attributes of miRNAs are that they exist in tissues at high abundance, and individual miRNAs can be highly tissue-specific. These miRNAs can be readily assayed in blood, urine, or cerebral spinal fluid, making them attractive as accessible biomarkers of tissue injury. Further, the miRNA processing involves embedding the miRNA within a protein complex, making them stable in plasma upon leakage from injured tissues. This review article will highlight the discovery of tissue-specific miRNAs and their evolution as novel toxicity biomarkers in recent years.

New methods for monitoring mitochondrial biogenesis and mitophagy invitro and invivo.

Removal of damaged mitochondria through mitophagy is critical for maintaining cellular homeostasis and functions. Increasing evidence implicates mitophagy in red blood cell differentiation, neurodegeneration, macrophage-mediated inflammation, ischemia, adipogenesis, drug-induced tissue injury, and cancer. Considerable progress has been made toward understanding the biochemical mechanisms involved in mitophagy regulation. However, few reliable assays to monitor and quantify mitophagy have been developed, particularly invivo. In this review, we summarize the recent development of three assays, MitoTimer, mt-Keima and mito-QC, for monitoring and quantifying mitophagy in cells and in animal tissues. We also discuss the advantages and limitations of these three assays when using them to monitor and quantify mitophagy. Impact statement Removal of damaged mitochondria through mitophagy is critical for maintaining cellular homeostasis and functions. However, reliable quantitative assays to monitor mitophagy, particularly invivo, are just emerging. This review will summarize the current novel quantitative assays to monitor mitophagy invivo.

Stem cell-derived models to improve mechanistic understanding and prediction of human drug-induced liver injury.

Current preclinical drug testing does not predict some forms of adverse drug reactions in humans. Efforts at improving predictability of drug-induced tissue injury in humans include using stem cell technology to generate human cells for screening for adverse effects of drugs in humans. The advent of induced pluripotent stem cells means that it may ultimately be possible to develop personalized toxicology to determine interindividual susceptibility to adverse drug reactions. However, the complexity of idiosyncratic drug-induced liver injury means that no current single-cell model, whether of primary liver tissue origin, from liver cell lines, or derived from stem cells, adequately emulates what is believed to occur during human drug-induced liver injury. Nevertheless, a single-cell model of a human hepatocyte which emulates key features of a hepatocyte is likely to be valuable in assessing potential chemical risk; furthermore, understanding how to generate a relevant hepatocyte will also be critical to efforts to build complex multicellular models of the liver. Currently, hepatocyte-like cells differentiated from stem cells still fall short of recapitulating the full mature hepatocellular phenotype. Therefore, we convened a number of experts from the areas of preclinical and clinical hepatotoxicity and safety assessment, from industry, academia, and regulatory bodies, to specifically explore the application of stem cells in hepatotoxicity safety assessment and to make recommendations for the way forward. In this short review, we particularly discuss the importance of benchmarking stem cell-derived hepatocyte-like cells to their terminally differentiated human counterparts using defined phenotyping, to make sure the cells are relevant and comparable between labs, and outline why this process is essential before the cells are introduced into chemical safety assessment. (Hepatology 2017;65:710-721).

The Predictive Safety Testing Consortium: safety bio-markers, collaboration, and qualification

The Predictive Safety Testing Consortium (PSTC) is one of nine consortia comprising the Critical Path Institute (C-Path), a non-profit organisation launched in 2005 and dedicated to playing the role of a catalyst in the development of new approaches that advance medical innovation and regulatory science. C-Path achieves this by lead-ing teams that share data, knowledge and expertise resulting in sound, consensus-based science. PSTC is a unique, public-private partnership that brings pharmaceutical companies together to share and validate safety testing methods under the advisement of worldwide regulatory agencies, including the US Food and Drug Administration (FDA), the European Medicines Agency (EMA), and the Japanese Pharmaceuticals and Medical Devices Agency (PMDA). The eighteen corporate members of PSTC share a common goal: to find improved safety testing methods and approaches utilizing fluid-based safety biomarkers which accurately predict drug-induced tissue injury. Specifically, the primary goal of PSTC is the qualification of novel translational safety biomarkers for use in early clinical trials in order to ena-ble safer investigations and development of new drug candidates. This manuscript describes the critical importance of improved safety biomarkers to the drug development process and the present state of the biomarker qualification process with regulatory agencies. In addition, the work that the PSTC and its collaborative partners have done and con-tinue to do to identify and qualify more selective and specific safety biomarkers is highlighted. Finally, successes in-cluding the recently adopted regulatory Letter of Support and ongoing efforts to better define the regulatory qualifica-tion process and an integrated translational safety strategy are also discussed.

The Predictive Safety Testing Consortium: safety biomarkers, collaboration, and qualification

The Predictive Safety Testing Consortium (PSTC) is one of nine consortia comprising the Critical Path Institute (C-Path), a non-profit organisation launched in 2005 and dedicated to playing the role of a catalyst in the development of new approaches that advance medical innovation and regulatory science. C-Path achieves this by lead-ing teams that share data, knowledge and expertise resulting in sound, consensus-based science. PSTC is a unique, public-private partnership that brings pharmaceutical companies together to share and validate safety testing methods under the advisement of worldwide regulatory agencies, including the US Food and Drug Administration (FDA), the European Medicines Agency (EMA), and the Japanese Pharmaceuticals and Medical Devices Agency (PMDA). The eighteen corporate members of PSTC share a common goal: to find improved safety testing methods and approaches utilizing fluid-based safety biomarkers which accurately predict drug-induced tissue injury. Specifically, the primary goal of PSTC is the qualification of novel translational safety biomarkers for use in early clinical trials in order to ena-ble safer investigations and development of new drug candidates. This manuscript describes the critical importance of improved safety biomarkers to the drug development process and the present state of the biomarker qualification process with regulatory agencies. In addition, the work that the PSTC and its collaborative partners have done and con-tinue to do to identify and qualify more selective and specific safety biomarkers is highlighted. Finally, successes in-cluding the recently adopted regulatory Letter of Support and ongoing efforts to better define the regulatory qualifica-tion process and an integrated translational safety strategy are also discussed.

Using silkworms to establish alternative animal models for evaluation of drug-induced tissue injury.

Evaluation of tissue injury induced by chemicals is crucial to drug development. Mice and rats, which are effectively used to analyze drug-induced tissue injury, present problems in terms of cost and ethical issues. Although alternative methods have been developed using in vitro techniques or invertebrates, evaluation of ADME and the size of animals are still issues that need to be addressed. Use of silkworms can resolve these problems. Silkworms have pharmacokinetic characteristics similar to those of mammals. Injection of various hepatotoxic chemicals also leads to elevated alanine aminotransferase (ALT) activity in the hemolymph of silkworms. Furthermore, transparent transgenic silkworms expressing GFP have been produced to facilitate continuous analysis without the need to collect hemolymph. Analyses using this silkworm have indicated that the intensity of GFP fluorescence observed on the body surface of the silkworm decreases in a time- and dose-dependent manner when hepatotoxic chemicals are injected. These results suggest that the silkworms can serve as alternative animal model for evaluation of drug-induced tissue injury.

Interleukin-17 in Drug Toxicity

Drug-induced tissue injury is the most common cause for termination of preclinical and clinical trial processes of drug development. Many drugs approved for clinical use have been withdrawn from market or have been advised to use with caution because of unexpected adverse effects noticed during postmarketing survelliance. Based on their relative importance in human health, some pharmaceuticals with relatively less drug toxicity, such as tolrestat, lumiracoxib and arotinin, have been approved in certain countries for use in patients, but not worldwide. Moreover, the surge in new drugs for human use has also increased the morbidity and mortality associated with adverse drug reactions. Although, over the years, investigative toxicology studies have unraveled mechanisms behind adverse drug reactions, the underlying pathogenesis of many drug toxicities are still unknown. Immune cells and inflammation have been attributed to majority of toxic effects of chemicals and drugs. The immune system may either be protective or detrimental to the host. For example, in cisplatin-induced kidney injury, dendritic cells, T regulatory cells and IL-10 attenuate, whereas T cells, NK cells and IL-17 aggravate nephrotoxicity [1,2]. Recently, interleukin-17 research has gained much importance as a drug target for autoimmune and inflammatory diseases.

Circulating MicroRNAs in Drug Safety Assessment for Hepatic and Cardiovascular Toxicity: The Latest Biomarker Frontier?

Drug-induced liver and cardiovascular injuries are important aspects of safety evaluations of numerous drugs in development. Therefore, reliable and predictive biomarkers to allow detection of early signs of drug-induced liver and cardiovascular injuries are required in clinical and preclinical pharmaceutical evaluation. MicroRNAs (miRNAs) are reported to be present in body fluids (blood, urine, etc.), and these 'circulating miRNAs' have been proposed as toxicological biomarkers of drug-induced tissue injury in preclinical and clinical practice. To be used as biomarkers of drug toxicity, such miRNAs need to show rapid and injured-tissue-specific upregulation in body fluids after injury, be more sensitive than existing protein markers such as alanine aminotransferase (ALT) and troponins, and be able to identify the toxicants responsible, if possible. In this article, we focus on the current knowledge of circulating miRNAs, which have potential for use in assessment of drug-induced liver and cardiovascular injuries. In addition, we discuss an important question regarding normalization of the expression levels of certain circulating miRNAs in body fluids.

Evaluation of drug-induced tissue injury by measuring alanine aminotransferase (ALT) activity in silkworm hemolymph

BackgroundOur previous studies suggest silkworms can be used as model animals instead of mammals in pharmacologic studies to develop novel therapeutic medicines. We examined the usefulness of the silkworm larvae Bombyx mori as an animal model for evaluating tissue injury induced by various cytotoxic drugs. Drugs that induce hepatotoxic effects in mammals were injected into the silkworm hemocoel, and alanine aminotransferase (ALT) activity was measured in the hemolymph 1 day later.ResultsInjection of CCl4 into the hemocoel led to an increase in ALT activity. The increase in ALT activity was attenuated by pretreatment with N-acetyl-L-cysteine. Injection of benzoic acid derivatives, ferric sulfate, sodium valproate, tetracycline, amiodarone hydrochloride, methyldopa, ketoconazole, pemoline (Betanamin), N-nitroso-fenfluramine, and D-galactosamine also increased ALT activity.ConclusionsThese findings indicate that silkworms are useful for evaluating the effects of chemicals that induce tissue injury in mammals.

Mitophagy: mechanisms, pathophysiological roles, and analysis

Abstract Mitochondria are essential organelles that regulate cellular energy homeostasis and cell death. The removal of damaged mitochondria through autophagy, a process called mitophagy, is thus critical for maintaining proper cellular functions. Indeed, mitophagy has been recently proposed to play critical roles in terminal differentiation of red blood cells, paternal mitochondrial degradation, neurodegenerative diseases, and ischemia or drug-induced tissue injury. Removal of damaged mitochondria through autophagy requires two steps: induction of general autophagy and priming of damaged mitochondria for selective autophagic recognition. Recent progress in mitophagy studies reveals that mitochondrial priming is mediated either by the Pink1-Parkin signaling pathway or the mitophagic receptors Nix and Bnip3. In this review, we summarize our current knowledge on the mechanisms of mitophagy. We also discuss the pathophysiological roles of mitophagy and current assays used to monitor mitophagy.