Frontiers in toxicology最新文献

Introduction: Shark and ray species are particularly vulnerable to pollutant bioaccumulation, including metals and metalloids, due to their k-strategist characteristics and mid-high trophic level. The angular angelshark (Squatina guggenheim) is a benthic and highly endangered species distributed from southeastern Brazil to southern Argentina. Despite being threatened with extinction and banned from marketing and consumption in Brazil, it is still widely consumed in several states. However, studies addressing metal and metalloid contamination in the meat of this species have not yet been conducted in Brazil.

Objectives: This study aimed to determine metal and metalloid contamination levels in S. guggenheim and to assess human health risks associated with its consumption by infants, children, teenagers, and adults, considering consumption frequencies ranging from one to five times per week.

Results: etal and metalloid concentrations in muscle tissue were generally lower than those reported for other benthic Squatinidae species, except for Pb and Rb. Several elements were reported for the first time in this species, providing baseline data. Although a favorable Se:Hg balance suggested a potential protective effect, multiple toxic and potentially toxic elements were detected, posing significant human health risks, particularly for infants and children. Arsenic concentrations exceeded Brazilian safety limits, while Ti and Rb were present at relatively high levels, despite the absence of established regulatory thresholds. Estimated intake values and non-carcinogenic risk indices (THQ and HI) surpassed safety limits for As (notably the inorganic As 10% fraction), Cu, MeHg, and Se in different scenarios, with As exceeding the acceptable threshold by up to 415 times, even under low-frequency consumption. Carcinogenic risk (CR) estimates indicated concerning levels for As and Pb across age groups.

Conclusions: The results highlight significant human health risks associated with the consumption of S. guggenheim, particularly for vulnerable populations such as infants and children. These findings highlight the urgent need for continuous monitoring of benthic elasmobranchs and reinforce caution regarding their consumption.

Agrichemicals such as herbicides, fungicides, insecticides, and biocides are widely used in agriculture, yet some are associated with adverse effects in humans and the environment. While many of these chemicals have been extensively studied in vitro and are included in the EPA's ToxCast program, comprehensive in vivo comparisons using RNA sequencing across structurally diverse agrichemicals, in a single screening platform, are lacking. In this study, we examined structurally diverse agrichemicals found in the U.S. Environmental Protection Agency's (EPA) Toxcast Phase I and II library by statically exposing early life stage zebrafish at 6 h post fertilization (hpf) until 120 hpf at concentrations ranging from 0.25 to 100 µM. Morphological outcomes were assessed at 120 hpf across 10 endpoints, including yolk sac edema, craniofacial malformations, and axis abnormalities. Chemicals that produced robust concentration-response relationships were selected for transcriptomic profiling. For transcriptomic analysis, zebrafish were statically exposed to each chemical and sampled at 48 hpf, prior to the onset of morphological effects observed at 120 hpf. Differential expression analysis identified between 0 and 4,538 differentially expressed genes (DEGs) per chemical, with no clear correlation to morphological severity. Both DEG and co-expression network analyses revealed chemical-specific expression patterns that converged on shared biological pathways, including neurodevelopment and cytoskeletal organization. Key regulatory genes such as mylpfa and krt4 were identified within co-expression modules, suggesting their potential role in conserved toxicity mechanisms. Semantic similarity analysis of enriched gene ontology (GO) terms, when compared to existing datasets, highlighted gaps in the annotation of neurodevelopmental processes, indicating that some in vivo effects may not be fully captured by current curated resources. The results provide new insights into the modes of action of diverse agrichemicals and establish a framework for understanding how agrichemical structure relates to biological function in a vertebrate model.

Introduction: The frequency of cyanobacterial blooms seems to have increased globally in recent decades due to human induced eutrophication and climate change. Cyanobacterial blooms can produce several groups of toxins, among which microcystin-LR (MC-LR) is one of the most abundant. Effects of MC-LR on avian microbiome have not been studied and studies in laboratory murines have been limited to metabarcoding of prokaryotes.

Methods: Using RNA shotgun sequencing, we compared the richness and composition of metabolically active prokaryotes, expressed virulence factors, antimicrobial resistance genes, metabolic pathways, Gene Ontology terms, enzymes, and proteins in mallards (Anas platyrhynchos) that were orally exposed to a sublethal dose of MC-LR for one week and unexposed birds.

Results: Richness and composition of all compared features did not differ between exposed and control birds and none were differentially expressed between exposure groups. However, richness and/or composition of all features except virulence factors and Carbohydrate Active enzymes had multiple-fold greater dispersion in exposed birds than in controls. This effect was especially pronounced in expressed metabolic (MetaCyc) pathways.

Discussion: Our results suggest that MC-LR exposure had a stochastic (rather than deterministic) effect on cecal microbiota, especially its function. Observed disturbance of the microbiota homeostasis is consistent with the Anna Karenina Principle. This principle has been documented in a wide range of eukaryotes using primarily microbial community metabarcoding. Although stochastic disturbance of microbiota function has been hypothesized, our study seems to be the first to demonstrate this in an experimental study.

Introduction: Iron oxide nanoparticle formulations are widely used in clinical applications and have recently been explored for hyperthermia therapy, cancer imaging and treatment. Here, we report the effects of intravenously injected pegylated or poly acrylic acid decorated iron oxide nanoparticles coated with hydroxyethyl starch (HES) on host immune system and organs. These particles were compared with sucrose coated iron oxide nanoparticle (Venofer^®) and the coating compound HES-both FDA approved agents-alongside non-iron oxide polystyrene nanoparticles coated with HES (micromer^®).

Methods: Toxicity analysis was performed in healthy female normal FVB/NJ mice 60 days after nanoparticle injection, with complete blood analysis conducted at multiple time-points. In a separate cohort, nanoparticle biodistribution 24 h post-intravenous injection was evaluated using a HER2 overexpressing breast cancer mouse model.

Results: Toxicity analysis revealed no adverse effects on liver or kidneys with any of the tested formulations after 60 days. Immune cell perturbations were observed at early time points following iron oxide nanoparticle injection but normalized by the study endpoint. Biodistribution analysis demonstrated that the nanoparticle coating dictated their accumulation across various organs, with significant tumor accumulation observed for pegylated iron oxide nanoparticles and Venofer^®.

Conclusion: Iron oxide nanoparticle formulations exert a transient effect on the host immune system and some exhibit tumor accumulation, suggesting their potential for further development in cancer imaging and treatment.

The European Food Safety Authority (EFSA) carries out safety assessments of newly expressed proteins (NEPs) in genetically modified organisms (GMOs). Here, toxicity and allergenicity assessments are the cornerstone of NEP evaluation, ensuring that any potential health hazards are rigorously identified and characterised. Recent examples of EFSA's NEP safety assessments illustrate how novel methodologies, alongside established ones reconsidered from new perspectives, guide case-by-case decisions. These advances provide an opportunity to improve the robustness, proportionality, and scientific credibility of risk assessments. Moreover, it may alleviate the need for in vivo animal testing. Building on this development, EFSA aims to integrate new approach methodologies (NAMs) into risk assessment to provide a scientific basis for waiving in vivo testing, aligning its approach with the 3Rs principles (Replacement, Reduction, Refinement) and the European Commission's roadmap for phasing out animal testing. Overall, this shift reflects a broader transformation in EFSA's safety assessment of NEPs, characterised by openness to innovation, optimisation of existing methods, and ensuring preparedness for future risk assessment needs. The ultimate goal is to ensure the highest level of protection for human and animal health, while embracing scientific progress.

Scientific confidence frameworks (SCFs) are alternatives to traditional validation for new approach methodologies (NAMs). The SCFs adapted by the Interagency Coordinating Committee for the Validation of Alternative Methods (ICCVAM) and the American Chemistry Council (ACC) both address inference performance-the ability of NAMs to predict or inform the biological effect of interest. Inference performance is a distinct evaluation procedure in ACC's SCF but is blended into several steps of ICCVAM's SCF. Here, we first reproduce the previously derived human relevant potency threshold (HRPT) for the estrogen receptor alpha (ERα) agonism of Borgert et al. (2018) using guideline and guideline-like studies; we found that a HRPT of 1 to 10^-1 positively and consistently predicted clinical endometrial and endocervical effects. We next mapped inference performance to ICCVAM's SCF and found that it can be used as an effective initial screen prior to performing more detailed characterizations in their SCF. We first conclude that a HRPT for ERα agonism of 10^-2 to 10^-4 is a health-protective NAM based on an established mode of action that could potentially be used in early screening, much like the threshold of toxicological concern. We then conclude that inference performance is a core requirement for SCFs.

New Approach Methodologies (NAMs) hold great potential to fill data gaps for chemicals and modernisation of chemical risk assessment practices. Current toxicity testing is based on conventional approaches with high reliability on in-vivo studies, but with time, regulators are trying to move towards in-vitro and in silico tools enabling efficient risk assessment strategies. Herein, we discuss about different emerging techniques which are or can become a NAM including both in-vitro and in silico models with particular focus on reducing animal studies and improving decision-making for hazard and exposure assessment. We also discussed about the way to strengthen the regulatory and public confidence in different NAMs and automation of these approaches. Some of these NAMs can help in identifying biochemical mechanisms for toxicity, calculate the point of departure (PoD), develop adverse outcome pathways (AOP), translate risk to multiple species and quantify uncertainty from predictions for multiple chemicals. Scientists and regulators can work together to frame robust guidelines for the practical application of these tools and ensure reproducible results.

There is increasing evidence that pesticides act as endocrine disruptors, developmental toxicants, and reproductive toxicants. In this review, we describe several global challenges associated with pesticide production and use that put the health of human and wildlife populations at risk. These include: (1) the global production and use of pesticides is high, leading to increasing rates of release into the environment; (2) exposures to non-target species (including humans) are well documented, and pesticides often have adverse effects on these species; (3) pesticides, and especially those that are persistent organic pollutants, do not stay where they are used, contributing to ecosystem pollution far from their intended areas of application; (4) climate change can exacerbate the use of pesticides; and (5) social determinants of health (race/ethnicity, sex, and occupation) influence pesticide exposures and the adverse effects associated with these exposures. In 2009, the concept of planetary boundaries was introduced as a framework to evaluate how human actions impact earth systems. The planetary boundaries were based on a shared understanding that human activities have significant and sometimes irreversible effects on key aspects of environmental health. When considering the global impact of pesticides, these products can disrupt several planetary boundaries including biogeochemical cycles, biosphere integrity (e.g., measures of biodiversity), and the availability of clean freshwater, but the greatest challenge posed by pesticides is the "novel entities" boundary (i.e., the introduction of synthetic chemicals and materials into the environment). The planetary boundaries framework makes clear that failure to act against the most concerning chemicals, including pesticides, ultimately puts the survival of human populations at risk.

Introduction: High-throughput screening (HTS) in vitro testing can be a powerful tool for evaluating chemicals across an abundance of mechanistic, targeted assay systems. This study reviewed HTS in vitro data for the systematic evaluation of endpoints relevant to carcinogenesis. To these means, we focused on assay endpoints from the ToxCast/Tox21 HTS program that have been mapped to Key Characteristics of Carcinogens (KCCs) to help focus our review on the ∼750 assay endpoints that have been previously identified as potentially informative for evaluating modes of action relevant to carcinogenesis.

Methods: Data for ToxCast/Tox21 HTS assay endpoints were retrieved from the publicly accessible invitrodb v4.2 and reviewed for five chlorotriazine herbicides (atrazine, cyanazine, propazine, simazine, and terbuthylazine) to evaluate any indication of cancer-relevant bioactivity. More specifically, we present a workflow comprising the use of a focused assay endpoint inventory based on KCC attribution, integration of assay flags to identify robust bioactivity, and putting in vitro mechanistic insights into context with literature-based context for toxicokinetic considerations and in vivo evidence.

Results and discussion: There were common targets consistently identified as bioactive across the chemical class including induction of estrone levels and potential CAR/PXR activation. These findings were put in context by utilizing in vivo data and knowledge about atrazine to weigh the evidence. Though the ToxCast/Tox21 HTS mechanistic assays did not yield novel insights into chlorotriazine carcinogenicity, our workflow exemplifies how starting from mechanistic screening data and integrating apical endpoints can be conducted. By providing context to in vitro ToxCast/Tox21 data with toxicokinetics information and available in vivo study outcomes demonstrates how the HTS data and KCC framework can be applied to review a chemical class for carcinogenicity potential.

Introduction: Fish cell lines represent a powerful tool for studying the biology and toxicology of aquatic species in compliance with the 3Rs principles. In addition, they hold potential for more advanced biotechnological applications. However, fish cell cultures are mainly cultivated with fetal bovine serum. Therefore, in this study, we investigated the impact of serum reduction and the effects of six growth factors and cytokines on a sturgeon larval cell line (AOXla7y), which has been previously proven to be a valuable model for climate change and toxicology studies.

Methods: The serum reduction (from 10% to 5% and 2%) and the addition of two concentrations (10 and 50 ng/mL) of six growth factors and cytokines (FGF-2, IGF-1, LIF, IFN-γ, IL-13, and IL-15) to the 2% serum growth medium were evaluated over 6 days of cultivation. The morphology and cell density were determined using phasecontrast images after the experiment ended, while real-time label-free cell impedance (xCELLigence) was recorded throughout the cultivation period. Moreover, the end-point oxygen consumption in basal and uncoupled respiration conditions was analyzed with the Seahorse XF Cell Mito Stress Test Kit.

Results: The results demonstrated a general adaptation of the sturgeon cell line to a serum-reduced environment and the modulatory effects of growth factor and cytokine supplementation on cell growth and metabolism.

Discussion: These findings suggest that the sturgeon cell line has the potential to transition to a serumfree medium without major observed morphological modifications and with a limited reduction in proliferation. Its metabolism was differentially modulated by the signaling of growth factors and cytokines and exhibited a variable metabolic phenotype under mitochondrial stress. This study provides a characterization of the Atlantic sturgeon cell metabolism and offers a preliminary assessment for developing an animal-free and chemically defined medium.