Search Results (51)

Honey is a valuable natural product prized for its nutritional and therapeutic properties, including antioxidant, antimicrobial, and anti-inflammatory effects. However, in addition to health-promoting compounds, honey may also contain plant-derived toxins, contaminants, and degradation products. Certain phytotoxins—such as pyrrolizidine alkaloids, grayanotoxins, triptolide, celastrol, gelsedine-type alkaloids, and tutin—can be transferred to honey from specific plant sources and pose health risks, particularly at high doses or with long-term exposure. Furthermore, compounds like 5-hydroxymethylfurfural, trace metals, pesticide residues, and Clostridium botulinum spores may present additional risks, especially to sensitive groups such as infants. Consumers often assume that natural products are inherently safe, which may lead to unintentional exposure to harmful substances. Adverse effects can range from chronic toxicity to, in extreme cases, death. Therefore, raising awareness among consumers and vendors is essential to reduce the intake of honey from unverified sources. Continuous monitoring of honey composition and further studies on the toxicodynamics of rare contaminants are crucial to ensuring safety while preserving the therapeutic benefits of this remarkable natural substance. Full article

The widespread production and poor management of plastic waste have led to the pervasive presence of microplastics (MPs) in environmental and biological systems. Among various polymers, polyethylene (PE) is the most widely produced plastic globally, primarily due to its use in single-use packaging. Its persistence in ecosystems and resistance to degradation processes result in the continuous formation of PE-derived MPs. These particles have been detected in human biological matrices, including blood, lungs, placenta, and even the brain, raising increasing concerns about their bioavailability and potential health effects. Once internalized, PE MPs can interact with cellular membranes, induce oxidative stress, inflammation, and apoptosis, and interfere with epigenetic regulatory pathways. In vitro studies on epithelial, immune, and neuronal cells reveal concentration-dependent cytotoxicity, mitochondrial dysfunction, membrane disruption, and activation of pro-inflammatory cytokines. Moreover, recent findings suggest that PE MPs can induce epithelial-to-mesenchymal transition (EMT), senescence, and epigenetic dysregulation, including altered expression of miRNAs and DNA methyltransferases. These cellular changes highlight the potential role of MPs in disease development, especially in cardiovascular, metabolic, and possibly cancer-related conditions. Despite growing evidence, no standardized method currently exists for quantifying MPs in human samples, complicating comparisons across studies. Further, MPs can carry harmful additives and environmental contaminants such as bisphenols, phthalates, dioxins, and heavy metals, which enhance their toxicity. Global estimates indicate that humans ingest and inhale tens of thousands of MPs particles each year, yet long-term human research remains limited. Given these findings, it is crucial to expand research on PE MP toxicodynamics and to establish regulatory policies to reduce their release. Promoting alternative biodegradable materials and improved waste management practices will be vital in decreasing human exposure to MPs and minimizing potential health risks. Full article

Povidone-iodine (PVP-I), a widely used aquaculture disinfectant, remains poorly understood in terms of sublethal toxicity and damage reversibility. This study employed Macrobrachium rosenbergii as the model organism to evaluate the acute toxicity and sublethal effects of PVP-I through a 4-day exposure experiment followed by a 7-day depuration period. Acute toxicity tests enabled the determination of 24–96 h median lethal concentrations (LC₅₀), with the 96 h LC₅₀ being 5.67 mg/L and the safe concentration (SC) being 1.37 mg/L. Based on this, three sublethal concentrations (1.14, 1.89, and 2.84 mg/L) were tested over a 4-day exposure followed by a 7-day depuration period. Investigated endpoints included gill ultrastructure, apoptosis, and antioxidant and immune-related gene expression. Subacute exposure at 1.89 and 2.84 mg/L induced mitochondrial vacuolization, upregulated apoptosis-related genes (Cyt-c, Caspase-3, Bok), and downregulated antioxidant gene expression (SOD, CAT, GSH-Px). The high-concentration group also showed sustained Toll-like receptor (Toll) gene overexpression and acid phosphatase (ACP) gene suppression. After depuration, antioxidant gene expression normalized; however, apoptotic markers in gill tissue remained impaired. Overall, high PVP-I concentrations cause irreversible gill damage via mitochondrial-mediated apoptosis, whereas lower concentrations (≤1.14 mg/L) allow for greater recovery. These results offer crucial toxicodynamic insights for safer PVP-I use and risk assessment in M. rosenbergii aquaculture. Full article

Background: Sirolimus (SRL, rapamycin) is a clinically important mTOR inhibitor used in immunosuppression, oncology, and cardiovascular drug-eluting devices. Despite its long-standing FDA approval, the human metabolic profile of SRL remains incompletely characterized. SRL is primarily metabolized by CYP3A enzymes in the liver and intestine, but the diversity, pharmacokinetics, and biological activity of its metabolites have been poorly explored due to the lack of structurally identified standards. Methods: To investigate SRL metabolism, we incubated SRL with pooled human liver microsomes (HLM) and isolated the resulting metabolites. Structural characterization was performed using high-resolution mass spectrometry (HRMS) and ion trap MSⁿ. We also applied Density Functional Theory (DFT) calculations to assess the energetic favorability of metabolic transformations and conducted molecular dynamics (MD) simulations to model metabolite interactions within the CYP3A4 active site. Results: We identified 21 unique SRL metabolites, classified into five major structural groups: O-demethylated, hydroxylated, didemethylated, di-hydroxylated, and mixed hydroxylated/demethylated derivatives. DFT analyses indicated that certain demethylation and hydroxylation reactions were energetically preferred, correlating with metabolite abundance. MD simulations further validated these findings by demonstrating the favorable orientation and accessibility of key sites within the CYP3A4 binding pocket. Conclusions: This study provides a comprehensive structural map of SRL metabolism, offering mechanistic insights into the formation of its metabolites. Our integrated approach of experimental and computational analyses lays the groundwork for future investigations into the pharmacodynamic and toxicodynamic effects of SRL metabolites on the mTOR pathway. Full article

Botanical insecticides derived from neem (Azadirachta indica A. Juss.) seeds have gained significant interest due to their sustainable characteristics and low environmental impact. However, their use in sericulture remains contentious due to the heightened sensitivity of domesticated silkworms to environmental stressors. This study systematically investigates the toxicodynamic effects of aqueous neem seed extract (ANSE) on fifth instar larvae of Thai multivoltine Bombyx mori L., focusing on larval mortality and carboxylesterase (CarE) enzyme activity in essential detoxification organs. Larvae were exposed to ANSE concentrations ranging from 5 to 50 mg L⁻¹ for up to 72 h. Key findings highlight a pronounced dose- and time-dependent increase in mortality, with an accurately determined LC₅₀ value of 17 mg L⁻¹ at the longest time exposure, accompanied by mortality rates reaching approximately 83% at the highest concentration tested, indicating considerable susceptibility. Additionally, notable and distinct organ-specific responses were observed, with significant inhibition of CarE activity in the midgut contrasting with elevated activities in the fat body and Malpighian tubules. These differential enzymatic responses reveal previously undocumented adaptive detoxification mechanisms. Consequently, the study advocates cautious and regulated application of neem-based insecticides in sericulture, recommending precise management of concentrations and exposure durations according to silkworm strain sensitivities to ensure optimal silk production. Full article

Objectives: There is growing concern over tyrosine kinase inhibitor (TKI)-induced cardiotoxicity, particularly regarding left ventricular dysfunction and heart failure in clinical treatment. These adverse effects often lead to treatment discontinuation, severely impacting patient outcomes. Therefore, there is an urgent need for more precise risk assessment methods. This study aimed to assess the cardiotoxicity of TKIs, refine in vitro to in vivo extrapolation (IVIVE) methodologies to improve predictive accuracy, and identify critical in vitro parameters for assessment. Methods: By leveraging high-throughput cardiotoxicity screening with human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), a mechanism-based toxicodynamic (TD) model for TKIs was constructed. A QSP-PK-TD model was developed by integrating pharmacokinetic (PK) and quantitative systems pharmacology (QSP) models. This model incorporates critical drug exposure factors, such as plasma protein binding, tissue–plasma partitioning, and drug distribution heterogeneity to enhance extrapolation accuracy. Results: The QSP-PK-TD model validated the reliability of IVIVE and identified the area under the curve of drug effects on mitochondrial membrane potential (AEMMP) and cardiomyocyte contractility (AEAAC) as key in vitro parameters for assessing TKI-induced cardiotoxicity. Incorporating critical drug exposure factors obviously improved qualitative and quantitative extrapolation accuracy. Conclusions: This study established a framework for predicting in vivo cardiotoxicity from in vitro parameters, enabling efficient translation of preclinical data into clinical risk assessment. These findings provide valuable insights for drug development and regulatory decision-making, offering a powerful tool for evaluating TKI-induced cardiotoxicity. Full article

Mycotoxins are secondary metabolites of filamentous fungi and ubiquitous dietary contaminants. Aflatoxins, a group of mycotoxins with high prevalence and toxicity, have raised a high level of public health concern, the most prevalent and toxic being aflatoxin B1 (AFB1). Many aspects appertaining to AFB1 poisoning are not well understood. Yet this information is necessary to devise appropriate surveillance and mitigation strategies against human and animal aflatoxicosis. This review provides an in-depth update of work carried out on mycotoxin poisoning, particularly aflatoxicosis in humans and animals, to identify gaps in knowledge. Hypotheses explaining the functional significance of mycotoxins in fungal biology and their dietary epidemiological data are presented and briefly discussed. The toxicology of aflatoxins and the challenges of their mitigation are discussed in depth. It was concluded that the identification of potential mycotoxin-hazard-prone food items and quantification of the associated risk of cancer ailments in humans is a prime priority. There is a dearth of reliable sampling methodologies for estimating AFB1 in animal feed. Data update on AFB1 in animal feed and its implication in animal production, mitigation strategies, and elucidation of risk factors to this hazard is required. To reduce the burden of aflatoxins, surveillance employing predictive technology, and biocontrol strategies seem promising approaches. Full article

Background: The blood–brain barrier (BBB) strictly regulates the penetration of substances into the brain, which, although important for maintaining brain homeostasis, may delay drug development because of the difficulties in predicting pharmacokinetics/pharmacodynamics (PKPD), toxicokinetics/toxicodynamics (TKTD), toxicity, safety, and efficacy in the central nervous system (CNS). Moreover, BBB functional proteins show species differences; therefore, humanized in vitro BBB models are urgently needed to improve the predictability of preclinical studies. Recently, international trends in the 3Rs in animal experiments and the approval of the FDA Modernization Act 2.0 have accelerated the application of microphysiological systems (MPSs) in preclinical studies, and in vitro BBB models have become synonymous with BBB–MPSs. Recently, we developed an industrialized humanized BBB–MPS, BBB–NET. In our previous report, we reproduced transferrin receptor (TfR)–mediated transcytosis with high efficiency and robustness, using hydrogels including fibrin and collagen I microfibers (CMFs). Methods: We investigated how adding CMFs to the fibrin gel benefits BBB-NETs. Results: We showed that CMFs accelerate capillary network formation and maturation by promoting astrocyte (AC) survival, and clarified that integrin β1 is involved in the mechanism of CMFs. Conclusions: Our data suggest that the quality control (QC) of CMFs is important for ensuring the stable production of BBB–NETs. Full article

Chironomids have a number of characteristics that make them a useful group for investigating the impact of environmental and chemical stressors on their life cycle stages. It is crucial to first understand sensitivities to environmental factors and provide a basis for interpreting the results of toxicity tests. We focused on Chironomus riparius–one of the most studied species in aquatic toxicity tests—to understand the changes during the larval stage under conditions of food abundance and limitation. We developed a model based on Dynamic Energy Budget (DEB) theory, a framework to capture the entire life cycle of an individual under varying food and temperature conditions. Available information from this study and the literature pointed out that the first three larval instars are immature and the fourth larval instar is mature, during which the organism saves, in two phases, energy for essential processes occurring during the subsequent non-feeding stages. The model can successfully predict the observed prolonged fourth instar duration under food limitation, the times of life history events (e.g., pupation and emergence), and egg production. This model has the potential to be integrated with toxicokinetic–toxicodynamic models to study the effects of toxicants on a variety of biological traits. Full article

Over the past decade, quetiapine has become one of the most commonly used psychotropic drugs in acute intoxication events worldwide. A structured literature review and analysis were conducted to assess the relationship between the kinetic and dynamic profiles in acute quetiapine intoxication. The correlation between dose and peak serum concentration (c_max) was determined using Pearson’s correlation coefficient. Binary logistic regression was used to evaluate dose and c_max as predictors of the most common clinical events, signs and symptoms. One hundred and thirty-four cases of acute quetiapine ingestion were included in the analysis, with a median ingested dose of 10 g and a median c_max of 4 mg/L. The typical half-life was estimated to be 16.5 h, significantly longer than at therapeutic doses. For the immediate-release formulation, a biphasic disposition could not be excluded. Dose and c_max demonstrated a weak but significant correlation (r = 0.256; N = 63; p = 0.043). Central nervous system depression and tachycardia were the most common clinical signs. Higher doses and concentrations increased the risk of severe intoxication and were good predictors of intubation, tachycardia, hypotension, QT_c prolongation and seizures, but not QRS prolongation, arrhythmia, heart block, hypokalaemia or acidosis. The thresholds for dose and c_max that increased the risk for individual signs and symptoms varied widely. However, doses > 3 g or c_max > 2 mg/L can be considered as alert levels that represent a high risk for severe clinical course of acute quetiapine intoxication. Full article

The European Rapid Alert System for Food and Feed (RASFF) has shown 1133 notifications for spices and herbs in the last 10 years (2013–2023). The analysis of these notifications indicated that 58.7% (665 alerts) of the alerts corresponded to chemical hazards. Mycotoxins corresponding to aflatoxin B1 (24 alerts) and ochratoxin A (39 alerts) were found in 19.4% of the samples. Due to the presence of these biological hazards in foodstuffs, comprehensive knowledge of their molecular mechanisms of action is required as part of the risk assessment strategy. Aflatoxin B1 (AFB1) is a known potent carcinogen that has been linked to liver cancer in humans and animals. Its toxic effects consist of forming DNA adducts, causing mutations, and interfering with cellular processes. On the other hand, ochratoxin A (OTA) is known to be nephrotoxic, hepatotoxic, carcinogenic, and immunosuppressive in both humans and animals. OTA targets the kidneys and liver, exerting its toxic effects similarly to AFB1, i.e., through DNA damage, oxidative stress, and interference with cellular processes. This communication reviews the molecular mechanism of action underlying the toxicity of AFB1 and OTA found in herbs and spices in Europe, focusing on their biosynthesis, toxicodynamics, interaction with cellular components, and the resulting biochemical pathways leading to adverse health effects. Moreover, it discusses potential strategies for mitigating their presence in spices, emphasizing the importance of hazard characterization for effective risk management and regulation. Full article

Pesticide exposure patterns tested in laboratory bioassays often do not match real-world pesticide exposure profiles in edge-of-field waterbodies. Toxicokinetic–toxicodynamic (TKTD) models are therefore increasingly used, as they allow for predictions of the toxic effects under actual time-variable field exposures. The TKTD models from the General Unified Threshold models of Survival (GUTS), for example, are considered ready for use by regulators for calculating the survival rates for any time-variable exposure profile. However, questions remain regarding their predictive power for compounds showing increased toxicity over time, such as neonicotinoid insecticides. The aim of the present study was therefore to compare the GUTS-predicted 28 d toxicity values of three neonicotinoids (imidacloprid, clothianidin, and thiamethoxam) for the common New Zealand mayfly genus Deleatidium spp. with those observed in a previously published study. Overall, the GUTS modeling results underestimated the toxicity values derived experimentally. From the three neonicotinoids, clothianidin showed the best fit between the estimated and observed 28 d LC₅₀ (median-lethal-concentration) values. Shortcomings of the modeling exercise, future research needs, and implications for the application of GUTS models in regulatory risk assessment are discussed. Full article

Γ-hydroxybutyric acid (GHB) is widely abused due to its sedative/hypnotic and euphoric effects. In recent years, GHB use has witnessed a notable rise within the LGBTQ+ community. GHB is a substrate of monocarboxylate transporters (MCTs) and exhibits nonlinear toxicokinetics, characterized by saturable metabolism, absorption, and renal reabsorption. This study investigates the impact of exogenous testosterone administration on GHB toxicokinetics and toxicodynamics, exploring the potential of MCT1 inhibition as a strategy to counteract toxicity. Ovariectomized (OVX) females and castrated (CST) male Sprague Dawley rats were treated with testosterone or placebo for 21 days. GHB was administered at two doses (1000 mg/kg or 1500 mg/kg i.v.), and the MCT1 inhibitor AR-C 155858 (1 mg/kg i.v.) was administered 5 min after GHB (1500 mg/kg i.v.) administration. Plasma and urine were collected up to 8 h post-dose, and GHB concentrations were quantified via a validated LC/MS/MS assay. Sleep time (sedative/hypnotic effect) was utilized as the toxicodynamic endpoint. Testosterone treatment significantly affected GHB toxicokinetics and toxicodynamics. Testosterone-treated CST rats exhibited significantly lower renal clearance, higher AUC, and increased sedative effect, while testosterone-treated OVX rats demonstrated higher metabolic clearance. AR-C 155858 treatment led to an increase in GHB renal and total clearance together with an improvement in sedative/hypnotic effect. In conclusion, exogenous testosterone treatment induces significant alterations in GHB toxicokinetics and toxicodynamics, and MCT inhibition can serve as a potential therapeutic strategy for GHB overdose in both cisgender and transgender male populations. Full article

In aquatic ecosystems, the interaction between heavy metals and dissolved organic carbon (DOC) plays a pivotal role in modifying the bioavailability of these metals. This study, employing a toxicokinetic–toxicodynamic model, delves into the interactive effects of humic acid (HA), a significant component of DOC, on the bioaccumulation and toxicity of copper (Cu) in the estuarine economic bivalve Sinonovacula constricta. Utilizing the stable isotope ⁶⁵Cu as a tracer, we evaluated Cu uptake in S. constricta under varied DOC concentrations in a controlled laboratory setting. Our findings reveal that at DOC concentrations below 3.05 mg L⁻¹, the bioavailability of Cu is reduced due to shifts in the speciation distribution of Cu, resulting in decreased bioaccumulation within S. constricta. Conversely, at DOC levels exceeding 3.05 mg L⁻¹, the formation of colloidal Cu–HA complexes allows its entry into the bivalves’ digestive system. Moreover, toxicity assays demonstrate an increase in S. constricta survival rates with higher DOC concentrations, suggesting a protective effect of DOC against Cu toxicity. The integration of accumulation and toxicity data infers that Cu–HA complexes, when ingested via the digestive tract, exhibit lower toxicity compared to Cu directly assimilated from the water phase. These findings emphasize the need to consider environmental DOC levels in assessing Cu pollution risks and provide insights for managing heavy metal toxicity in estuarine aquaculture. Full article

The aim of this study is to investigate the role of cellular sulfhydryl and glutathione (GSH) status in cellular cadmium (Cd) accumulation using cultures of the rainbow trout cell line RTG-2. In a first set of experiments, the time course of Cd accumulation in RTG-2 cells exposed to a non-cytotoxic CdCl₂ concentration (25 μM) was determined, as were the associated changes in the cellular sulfhydryl status. The cellular levels of total GSH, oxidized glutathione (GSSG), and cysteine were determined with fluorometric high-performance liquid chromatography (HPLC), and the intracellular Cd concentrations were determined with inductively coupled plasma mass spectrometry (ICP-MS). The Cd uptake during the first 24 h of exposure was linear before it approached a plateau at 48 h. The metal accumulation did not cause an alteration in cellular GSH, GSSG, or cysteine levels. In a second set of experiments, we examined whether the cellular sulfhydryl status modulates Cd accumulation. To this end, the following approaches were used: (a) untreated RTG-2 cells as controls, and (b) RTG-2 cells that were either depleted of GSH through pre-exposure to 1 mM L-buthionine-SR-sulfoximine (BSO), an inhibitor of glutathione synthesis, or the cellular sulfhydryl groups were blocked through treatment with 2.5 μM N-ethylmaleimide (NEM). Compared to the control cells, the cells depleted of intracellular GSH showed a 25% reduction in Cd accumulation. Likewise, the Cd accumulation was reduced by 25% in the RTG-2 cells with blocked sulfhydryl groups. However, the 25% decrease in cellular Cd accumulation in the sulfhydryl-manipulated cells was statistically not significantly different from the Cd accumulation in the control cells. The findings of this study suggest that the intracellular sulfhydryl and GSH status, in contrast to their importance for Cd toxicodynamics, is of limited importance for the toxicokinetics of Cd in fish cells. Full article