The long way from raw data to NAM-based information: Overview on data layers and processing steps.

Toxicological test methods generate raw data and provide instructions on how to use these to determine a final outcome such as a classification of test compounds as hits or non-hits. The data processing pipeline provided in the test method description is often highly complex. Usually, multiple layers of data, ranging from a machine-generated output to the final hit definition, are considered.

A weight of evidence review on the mode of action, adversity, and the human relevance of xylene's observed thyroid effects in rats.

Xylene substances have wide industrial and consumer uses and are currently undergoing dossier and substance evaluation under Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) for further toxicological testing including consideration of an additional neurotoxicological testing cohort to an extended one-generation reproduction toxicity (EOGRT) study. New repeated dose study data on xylenes identify the thyroid as a potential target tissue, and therefore a weight of evidence review is provided to investigate whether or not xylene-mediated changes on the hypothalamus-pituitary-thyroid (HPT) axis are secondary to liver enzymatic induction and are of a magnitude that is relevant for neurological human health concerns. Multiple published studies confirm xylene-mediated increases in liver weight, hepatocellular hypertrophy, and liver enzymatic induction the oral or inhalation routes, including an increase in uridine 5'-diphospho-glucuronosyltransferase (UDP-GT) activity, the key step in thyroid hormone metabolism in rodents.

The short-term toxicity and metabolome of Benzene.

A 14-day rat study with plasma metabolomics was conducted to evaluate the toxicity of Benzene. Wistar rats were orally administered Benzene daily at doses of 0, 300 and 1000 mg/kg bw. The study identified liver and kidneys as target organs of Benzene toxicity and found reductions in total white blood cells, absolute lymphocyte and eosinophil cell counts, and increased relative monocyte counts suggesting bone marrow as a target organ.

Demonstrating the reliability of in vivo metabolomics based chemical grouping: towards best practice.

While grouping/read-across is widely used to fill data gaps, chemical registration dossiers are often rejected due to weak category justifications based on structural similarity only. Metabolomics provides a route to robust chemical categories via evidence of shared molecular effects across source and target substances. To gain international acceptance, this approach must demonstrate high reliability, and best-practice guidance is required.

Molecular signatures of angiogenesis inhibitors: a single-embryo untargeted metabolomics approach in zebrafish.

Angiogenesis is a key process in embryonic development, a disruption of this process can lead to severe developmental defects, such as limb malformations. The identification of molecular perturbations representative of antiangiogenesis in zebrafish embryo (ZFE) may guide the assessment of developmental toxicity from an endpoint- to a mechanism-based approach, thereby improving the extrapolation of findings to humans. Thus, the aim of the study was to discover molecular changes characteristic of antiangiogenesis and developmental toxicity.

BMI increase during early childhood in boys with cystic fibrosis and early adrenarche.

Background: Increase in body mass index (BMI) in early childhood (1-6 years) was found to be a contributing factor for impaired final height in boys with Cystic Fibrosis (CF). Early adrenarche (before age 9 years in boys) may contribute to an impaired final height by triggering an early acceleration of bone age resulting in a compromised growth spurt during puberty. We aimed to analyze the timing of adrenarche in boys with CF and to associate BMI increase in early childhood to timing of adrenarche.

Utility of in vivo metabolomics to support read-across for UVCB substances under REACH.

Structure-based grouping of chemicals for targeted testing and read-across is an efficient way to reduce resources and animal usage. For substances of unknown or variable composition, complex reaction products, or biological materials (UVCBs), structure-based grouping is virtually impossible. Biology-based approaches such as metabolomics could provide a solution.

Thyroid Hormone Metabolites Quantified in Pup and Adult Rat Cerebellum, Cortex and Whole-Brain Samples Using an Automated Online SPE-LC-MS/MS Method.

Changes in thyroid hormone (TH) levels in rat brain at early developmental stages are correlated with adverse effects on offspring development. To characterize the ability of substances to interfere with the TH concentrations in, e.g.

Embedding routine health care data in clinical trials: with great power comes great responsibility.

Randomised clinical trials (RCTs) are vital for medical progress. Unfortunately, 'traditional' RCTs are expensive and inherently slow. Moreover, their generalisability has been questioned.

The short-term toxicity and metabolome of dicyclopentadiene.

Dicyclopentadiene (DCPD) was investigated in a 14-day oral rat toxicity study based on the OECD 407 guideline in combination with plasma metabolomics. Wistar rats received the compound daily via gavage at dose levels of 0, 50 and 150 mg/kg bw. The high dose induced transient clinical signs of toxicity and in males only reduced body weight gain.

A Novel and Fast Online-SPE-LC-MS/MS Method to Quantify Thyroid Hormone Metabolites in Rat Plasma.

Since the focus in regulatory toxicology has drifted toward the identification of endocrine disruptors, the improvement in determination of alterations in the thyroid hormone system has become more important. THs are involved in several molecular processes important for a proper pre- and postnatal development so that disturbances can inter alia lead to incorrect brain maturation and/or disturbed metabolic processes (thermogenesis or lipolysis). In this publication, a new automated online solid-phase extraction (SPE)-liquid chromatography (LC)-tandem mass spectrometry (MS/MS, xLC-MS/MS) is introduced which simultaneously analyzes total T4, T3, rT3, T2, and T1.

Safety of Antenatal Predniso(lo)ne and Dexamethasone on Fetal, Neonatal and Childhood Outcomes: A Systematic Review.

Context: Due to ethical considerations, antenatal dose finding for prednisolone and dexamethasone in pregnant women is limited, leading to a knowledge gap.

Objective: In order to guide the clinician in weighing benefits vs risks, the aim is to systematically review the current literature on the side effects of antenatal predniso(lo)ne and dexamethasone use on the fetus, newborn, and (pre)pubertal child.

Evidence Acquisition: The search was performed in PubMed/MEDLINE and Embase using prespecified keywords and Medical Subject Headings.

Application of high throughput in vitro metabolomics for hepatotoxicity mode of action characterization and mechanistic-anchored point of departure derivation: a case study with nitrofurantoin.

Omics techniques have been increasingly recognized as promising tools for Next Generation Risk Assessment. Targeted metabolomics offer the advantage of providing readily interpretable mechanistic information about perturbed biological pathways. In this study, a high-throughput LC-MS/MS-based broad targeted metabolomics system was applied to study nitrofurantoin metabolic dynamics over time and concentration and to provide a mechanistic-anchored approach for point of departure (PoD) derivation.

Assessing the Influence of Propylthiouracil and Phenytoin on the Metabolomes of the Thyroid, Liver, and Plasma in Rats.

The thyroid hormones (THs) regulate various physiological mechanisms in mammals, such as cellular metabolism, cell structure, and membrane transport. The therapeutic drugs propylthiouracil (PTU) and phenytoin are known to induce hypothyroidism and decrease blood thyroid hormone levels. To analyze the impact of these two drugs on systemic metabolism, we focused on metabolic changes after treatment.

A metabolomics approach to reveal the mechanism of developmental toxicity in zebrafish embryos exposed to 6-propyl-2-thiouracil.

A crucial component of a substance registration and regulation is the evaluation of human prenatal developmental toxicity. Current toxicological tests are based on mammalian models, but these are costly, time consuming and may pose ethical concerns. The zebrafish embryo has evolved as a promising alternative model to study developmental toxicity.

A high-throughput metabolomics in vitro platform for the characterization of hepatotoxicity.

Cell-based metabolomics provides multiparametric physiologically relevant readouts that can be highly advantageous for improved, biologically based decision making in early stages of compound development. Here, we present the development of a 96-well plate LC-MS/MS-based targeted metabolomics screening platform for the classification of liver toxicity modes of action (MoAs) in HepG2 cells. Different parameters of the workflow (cell seeding density, passage number, cytotoxicity testing, sample preparation, metabolite extraction, analytical method, and data processing) were optimized and standardized to increase the efficiency of the testing platform.

Connecting Gut Microbial Diversity with Plasma Metabolome and Fecal Bile Acid Changes Induced by the Antibiotics Tobramycin and Colistin Sulfate.

The diversity of microbial species in the gut has a strong influence on health and development of the host. Further, there are indications that the variation in expression of gut bacterial metabolic enzymes is less diverse than the taxonomic profile, underlying the importance of microbiome functionality, particularly from a toxicological perspective. To address these relationships, the gut bacterial composition of Wistar rats was altered by a 28 day oral treatment with the antibiotics tobramycin or colistin sulfate.

Gut Microbiota as Well as Metabolomes of Wistar Rats Recover within Two Weeks after Doripenem Antibiotic Treatment.

An understanding of the changes in gut microbiome composition and its associated metabolic functions is important to assess the potential implications thereof on host health. Thus, to elucidate the connection between the gut microbiome and the fecal and plasma metabolomes, two poorly bioavailable carbapenem antibiotics (doripenem and meropenem), were administered in a 28-day oral study to male and female Wistar rats. Additionally, the recovery of the gut microbiome and metabolomes in doripenem-exposed rats were studied one and two weeks after antibiotic treatment (i.

Analysis of therapy monitoring in the International Congenital Adrenal Hyperplasia Registry.

Objective: Congenital adrenal hyperplasia (CAH) requires exogenous steroid replacement. Treatment is commonly monitored by measuring 17-OH progesterone (17OHP) and androstenedione (D4).

Design: Retrospective cohort study using real-world data to evaluate 17OHP and D4 in relation to hydrocortisone (HC) dose in CAH patients treated in 14 countries.

Investigating the gut microbiome and metabolome following treatment with artificial sweeteners acesulfame potassium and saccharin in young adult Wistar rats.

To elucidate if artificial sweeteners modify fecal bacterial composition and the fecal and plasma metabolomes, Wistar rats from both sexes were treated for 28 days with acesulfame potassium (40 and 120 mg/kg body weight) and saccharin (20 and 100 mg/kg body weight). Targeted MS-based metabolome profiling (plasma and feces) and fecal 16S gene sequencing were conducted. Both sweeteners exhibited only minor effects on the fecal metabolome and microbiota.

Next-generation risk assessment of chemicals - Rolling out a human-centric testing strategy to drive 3R implementation: The RISK-HUNT3R project perspective.

In many industrial sectors, there is a need for reliable ways to evaluate the safety of chemicals with methods anchored to human biology and pathology. For this purpose, many animal-free new approach methods (NAMs) have been developed and implemented in various stages of risk assessment. Now it is time to assemble individual NAMs into a comprehensive next-generation risk assessment (NGRA) strategy.

Optimizing the Timing of Highest Hydrocortisone Dose in Children and Adolescents With 21-Hydroxylase Deficiency.

Context: Hydrocortisone treatment of young patients with 21-hydroxylase deficiency (21OHD) is given thrice daily, but there is debate about the optimal timing of the highest hydrocortisone dose, either mimicking the physiological diurnal rhythm (morning), or optimally suppressing androgen activity (evening).

Objective: We aimed to compare 2 standard hydrocortisone timing strategies, either highest dosage in the morning or evening, with respect to hormonal status throughout the day, nocturnal blood pressure (BP), and sleep and activity scores.

Methods: This 6-week crossover study included 39 patients (aged 4-19 years) with 21OHD.

Use of in vitro metabolomics in NRK cells to help predicting nephrotoxicity and differentiating the MoA of nephrotoxicants.

We describe a strategy using an in vitro metabolomics assay with tubular rat NRK-52E cells to investigate the Modes of Action (MoAs) of nephrotoxic compounds. Chemicals were selected according to their MoAs based on literature information: acetaminophen, 4-aminophenol and S-(trichlorovinyl-)L-cysteine (TCVC), (covalent protein binding); gentamycin, vancomycin, polymycin B and CdCl (lysosomal overload) and tenofovir and cidofovir (mitochondrial DNA-interaction). After treatment and harvesting of the cells, intracellular endogenous metabolites were quantified relative to vehicle control.

The Efficacy, Safety, and Side Effects of Intrapericardial Triamcinolone Treatment in Children with Post-surgical Pericardial Effusion: A Case Series.

Intrapericardial triamcinolone can be used to treat chronic pericardial effusion (PE) in adults; however, pediatric data are lacking. In this case series we aim to evaluate the efficacy, safety, and side effects of intrapericardial triamcinolone in children with PE. The incidence and treatment of post-surgical PE from 2009 to 2019 were determined using the institutional surgical database and electronic patient records.