Designer benzodiazepines (DBZDs) are a class of new psychoactive substances (NPS) designed as legal alternatives to prescription BZDs. Bromazolam has been the most prevalent DBZD detected on the recreational market around the world; however, a new DBZD, ethylbromazolam (8-bromo-1-ethyl-6-phenyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine; also known as bromoethylazolam) has recently emerged. In this study, the emergence of ethylbromazolam in Canada, the UK, and Australia is reported based on analysis of samples from drug checking services and in Germany based on analysis of samples seized by customs and mail services. Since November 2024, ethylbromazolam has been increasingly detected with a concurrent decrease in bromazolam detections, suggesting that its emergence is likely in response to the international control of bromazolam on 3rd December 2024. Additionally, increased detections of other DBZDs, including desalkylgidazepam (bromonordiazepam) and clobromazolam (phenazolam) have been recently observed. The in vitro α1β2γ2 GABAA receptor activity of ethylbromazolam was determined using an automated patch clamp assay. Ethylbromazolam was found to have similar in vitro GABAA receptor activity as bromazolam (EC50 of 10.1 nM and 15.2 nM, respectively), indicating comparable pharmacological activity and potential for harm. The market should continue to be monitored closely as it continues to evolve in response to the control of bromazolam.

2,5-Dimethylfuran (DMF) is a heat-induced contaminant found in various thermally processed foods. Due to its structural similarity to furan, a well-known hepatotoxin and potential human carcinogen, the presence of DMF in food poses a potential risk to consumers. DMF undergoes cytochrome P450 (CYP)-mediated biotransformation leading to the formation of two primary phase-I metabolites: the reactive cis-3-hexene-2,5-dione (HDO), which can react with cellular nucleophiles, and the primary alcohol 5-methylfurfuryl alcohol (MFA), formed after hydroxylation of the alkyl moiety. To deduce the in vitro formation kinetics of these two phase-I metabolites, we utilised a newly developed HPLC-ESI-MS/MS method to quantify HDO after scavenging with glutathione and monitored the formation of MFA by GC-MS in parallel. Metabolic activation and the formation of HDO was the predominant biotransformation pathway in human liver microsomes, whereas the parallel formation of MFA was significantly less efficient. In line with data on the metabolic activation of furan, CYP2E1 was the most active human CYP-isoform in the potential metabolic activation of DMF. However, CYP3A4 and CYP2D6 also contributed to the HDO formation in vitro. Hydroxylation of DMF and formation of MFA were exclusively catalysed by CYP2E1. Despite the formation of MFA as an alternative metabolic pathway, our kinetic data indicate that DMF is primarily metabolised by CYP2E1 to the reactive cis-enedial intermediate HDO, particularly at physiologically relevant concentrations. Therefore, exposure to DMF may contribute to the overall risk associated with dietary exposure to furans.

Abstract Perfluorooctanesulfonic acid (PFOS) is an environmental contaminant with a long half-life in animals. Risk assessment of PFOS in livestock and food tissue can be conducted with physiologically-based kinetic (PBK) models. For fast-growing livestock, changes in body weight affect the kinetics of PFOS primarily through tissue dilution, which needs to be considered when using a PBK model. A generic PBK model was used to predict tissue concentrations of PFOS in cattle, sheep, and chickens. The primary excretion routes were feces and urine, which were affected by enterohepatic circulation and saturable tubular reabsorption, respectively. Animal weight gain was modeled using the sigmoidal Richards curve. Model performance was validated by comparing simulations, with or without growth, to independent literature data. Blood and plasma concentrations of independent cattle and chicken data were accurately predicted. Liver and kidney concentrations were overpredicted by up to five-fold and three-fold, respectively, in cattle, and twelve-fold for liver in chickens. Liver concentrations in sheep were accurately predicted. Muscle concentrations were overpredicted in cattle by up to three-fold. Predictions using constant body weights differed from the growth PBK predictions by up to 80%, 12%, and 60% in cattle, sheep, and chicken tissue, respectively. Integration of growth in the PBK model led to improved accuracy in concentration predictions. Tissue concentration predictions could be improved using reliable partition coefficient estimates. The presented model closed gaps in previously developed models by integrating growth and PFOS-specific processes such as enterohepatic circulation and tubular reabsorption.

Microplastics and nanoplastics (MNPs) are becoming ubiquitous environmental pollutants, with increasing evidence of their systemic toxicity. MNPs are increasingly detected in human tissues, including the cardiovascular system, and have been implicated in the pathogenesis of cardiovascular disease through mitochondrial dysfunction. This review integrates mechanistic insights into how MNPs impair mitochondrial integrity, induce oxidative stress, disrupt calcium signaling, and promote genomic instability in cardiac tissue. MNPs also exacerbate inflammation, cellular senescence, mitophagy dysfunction, and pro-atherosclerotic remodeling. Furthermore, this review examines sex-specific mitochondrial responses and developmental vulnerabilities. Understanding the molecular crosstalk between MNPs exposure and mitochondrial damage may provide a foundation for targeted interventions to mitigate environmental cardiovascular risks.

Functionalisation of carbon nanotubes (CNTs), to make them more hydrophilic, is an essential step in their preparation for use in a wide range of industrial processes. The toxicological impact of these modifications has been investigated. However, due to the diversity of experimental models used in studies, no consensus has yet been reached. Here, we studied the toxicity of multi-walled CNT (MWCNT) with or without hydroxyl or carboxyl functional groups in lung cell models-chosen due to the risk of inhalation exposure for employees during handling of nanomaterials. In this study, we investigated the induction of the epithelial-mesenchymal transition (EMT) of human bronchial epithelial cells BEAS-2B following 6 weeks of treatment with MWCNTs ranging from 0.125 to 1µg/cm2. Epithelial and mesenchymal markers were modified following MWCNT treatment, confirming the induction of the EMT. The effect was more pronounced with non-functionalised MWCNTs than with functionalised ones. In the lung carcinoma cell line A549, IL-8 expression was measured following treatment for 24h to 0.5-10µg/cm2 MWCNTs. An equal to or lower level was observed after treatment with functionalised MWCNTs than non-functionalised MWCNTs. Finally, the rat alveolar macrophage cell line NR8383 were exposed to 0.125-10µg/cm2 to MWCNTs for 24h. Non-functionalised MWCNTs led to a higher proportion of binucleation than exposure to their functionalised counterparts. Functionalised MWCNTs induce toxicity in lung cell lines to a lower extent than non-functionalised MWCNTs. Because of this toxicity, all MWCNTs should be handled with care regardless of their functionalisation.

Per- and polyfluoroalkyl substances (PFASs) are man-made organofluoride chemicals widely present in the environment, with exposure associated to various adverse health effects, including immunotoxicity. Recently, we showed that PFASs can directly impair antibody production, leading to decreased immunoglobulin (Ig) M and IgG release in human peripheral blood mononuclear cells (PBMCs) obtained from both male and female healthy donors. However, the underlying molecular mechanisms remain largely unknown. In this study, we aimed to address this gap by performing RNA sequencing to identify pathways and genes potentially involved in the observed immunotoxic effects. PBMCs were exposed to selected PFASs for 24 h, and to assess effects on antibody secretion, a subset was subsequently stimulated with CpG oligodeoxynucleotide ODN2006 and rhIL-2 for an additional six days. Transcriptomic analysis indicated activation of the glucocorticoid receptor (GR) and associated signaling pathways, supported by the upregulation of several GR-target genes and the prediction of glucocorticoids or the GR agonist dexamethasone as upstream regulators in Ingenuity Pathway Analysis. Moreover, the inhibitory effects of PFASs on antibody secretion were shown to be reversable by the GR antagonist Mifepristone, supporting the involvement of the GR in PFAS-mediated suppression of antibody secretion. Overall, this research advances our understanding of PFAS-induced immunotoxicity and identifies potential biomarkers for evaluating PFAS exposure and its associated health effects.

Abstract Novichoks are the latest known and most toxic class of organophosphorus chemical warfare agents (OP CWAs) to have been developed. Among the documented Novichoks, A-232 is the most toxic and most potent inhibitor of AChE, as well as the most resistant to reactivation by oximes, and thus likely the most challenging to treat. Here we characterize the intoxication following dermal exposure to the Novichok A-232 in swine, and describe a novel countermeasure against it. Our results demonstrate that percutaneous poisoning by a lethal dose of A-232 (2 mg/kg) is characterized by slow appearance and exacerbation of intoxication signs. We further show that conventional antidotal treatment against such poisoning, administered upon appearance of intoxication signs, provides only temporary relief after which intoxication signs reoccur, and that further repeated such treatment is not sufficient to enable survival. The above likely stem from formation of a dermal depot of A-232 from which the agent slowly penetrates into the bloodstream, coupled with its resistance to reactivation by oximes. Accordingly, we developed the AHAK lotion (potassium acetohydroxamate in DMSO/H 2 O, derived from the FDA approved medication acetohydroxamic acid (AHA)), intended to act as a ‘catch-up therapy’ enabling both skin surface and intradermal decomposition of persistent low-volatility OP CWAs. We demonstrate that combining conventional antidotal treatment with dermal application of AHAK following percutaneous poisoning by a lethal dose of A-232, leads to survival of all animals. Additionally, using a low dose (0.33–0.41 mg/kg) of A-232, we show that AHAK is expected to exert a beneficial effect also following late application. Hence, the results of the current study, coupled with our previous results regarding the contribution of AHAK to countering percutaneous intoxication by VX and the safety of prolonged whole-body application of AHAK, delineate the aptness of AHAK to serve as a generic medical countermeasure against percutaneous intoxication by persistent low-volatility OP CWAs, of both the V and Novichok families.

Per- and polyfluoroalkyl substances (PFASs) are pervasive in airborne particles and aerosols, making inhalation a critical exposure pathway; however, the lack of inhalation toxicity data hinders accurate risk assessment and public health protection. In this study, we developed quantitative structure-activity relationship (QSAR) and quantitative read-across structure-activity relationship (q-RASAR) models to predict the acute inhalation toxicity of PFASs. The models were constructed using mechanistically interpretable two-dimensional molecular descriptors, and the integration of similarity-based descriptors enhanced predictive performance while maintaining model simplicity and interpretability. All validated models were applied to untested PFASs for toxicity prediction and priority ranking. In addition, interspecies toxicity (iST) models were established to explore toxicity relationships between rats and mice, enabling cross-species extrapolation. Collectively, these QSAR, q-RASAR, and iST models address the critical data gap in PFAS inhalation toxicology, providing a rapid and reliable tool for regulators and researchers to support science-driven risk assessment and public health protection against airborne PFAS exposure.

Disruption of the thyroid hormone (TH) system by environmental chemicals poses significant risks to human and wildlife health. Reliable in vitro assays are essential for assessing thyroid peroxidase (TPO) inhibition, which disrupts a key step in thyroid hormone (TH) synthesis, while adhering to 3R principles. This study aimed to compare the sensitivity and specificity of two types of in vitro assays, tyrosine iodination (Tyr-I) detected by HPLC-ICP-MS and Amplex UltraRed (AUR) and its modifications, using human HEK-TPOA7 cells and rat thyroid microsomes. It involved the evaluation of TPO inhibition by 21 chemicals (concentration range 0.002-200µM) from diverse use categories, including industrial pollutants, pesticides, and pharmaceuticals. TPO-inhibition potential was indicated for 14 compounds. The Tyr-I assay, which measures the conversion of L-tyrosine to monoiodotyrosine, demonstrated superior sensitivity by capturing both the peroxidation and iodination steps of TPO activity, with effective concentrations for some human exposure-relevant chemicals (benzophenone 2, resorcinol) in the 15-74nM range confirmed with both human and rat TPO sources. In contrast, the AUR assay detects only the peroxidation step, limiting its ability to fully assess TPO inhibition. The inclusion of sodium iodide (NaI) in the AUR assay significantly enhanced its sensitivity (though it was still lower than in Tyr-I assay), while adding L-tyrosine together with NaI did not. The study documents the advantages and limitations, as well as the application and interpretation potential of the different assays´ variants. It provides valuable information and scientifically sound methodology to support the development of efficient testing strategies for the assessment of thyroid hormone system-disrupting chemicals.