Search Results (101)

Developmental exposure to polybrominated diphenyl ethers (PBDEs), which are commonly used as flame retardants, results in irreversible cognitive impairments. Postnatal hippocampal neurogenesis, which occurs in the subgranular zone (SGZ) of the dentate gyrus, is critical for neuronal circuits and plasticity. Wnt7a-Frizzled5 (FZD5) is essential for both neurogenesis and synapse formation; moreover, Wnt signaling participates in PBDE neurotoxicity and also contributes to the neuroprotective effects of melatonin. Therefore, we investigated the impacts of perinatal decabromodiphenyl ether (BDE-209) exposure on hippocampal neurogenesis and synaptogenesis in juvenile rats through BrdU injection and Golgi staining, as well as the alleviation of melatonin pretreatment. Additionally, we identified the structural basis of Wnt7a and two compounds via molecular docking. The hippocampal neural progenitor pool (Sox2+BrdU+ and Sox2+GFAP+cells), immature neurons (DCX+) differentiated from neuroblasts, and the survival of mature neurons (NeuN+) in the dentate gyrus were inhibited. Moreover, in BDE-209-exposed offspring rats, it was observed that dendritic branching and spine density were reduced, alongside the long-lasting suppression of the Wnt7a-FZD5/β-catenin pathway and targeted genes (Prox1, Neurod1, Neurogin2, Dlg4, and Netrin1) expression. Melatonin alleviated BDE-209-disrupted memory, along with hippocampal neurogenesis and dendritogenesis, for which the restoration of Wnt7a-FZD5 signaling may be beneficial. This study suggested that melatonin could represent a potential intervention for the cognitive deficits induced by PBDEs. Full article

Soil washing is an efficient method to remove polybrominated diphenyl ethers (PBDEs) from contaminated soils. The obtained solutions from soil-washing still contain PBDEs, requiring further treatment before disposal or reuse. Although photolysis is effective for PBDE degradation in solutions, the concurrent formation of toxic polybrominated dibenzofurans (PBDFs) may limit its practical application. In this study, 2,8-dibromodibenzofurans (2,8-BDF) formation rate and mechanisms during 2,4,4′-tribromodiphenyl ether (BDE-28) photolysis in various simulated soil-washing solutions was investigated. Results revealed significant effects of solubilizers on 2,8-BDF formation. The nonionic surfactants polysorbate (TW80), polyoxyethylene octylphenyl ether (TX series), and the cationic surfactant cetyltrimethylammonium bromide (CTAB) resulted in low 2,8-BDF formation rate (1–5%), while the β-cyclodextrin led to the highest 2,8-BDF formation rate (about 28%). The nonionic surfactants polyoxyethylene dodecyl ethers (Brij series), and the anionic surfactants sodium dodecylbenzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS), also showed a high level of 2,8-BDF formation rate (7–17%). Solubilizer structure and its interaction with BDE-28 determined the 2,8-BDF formation. The role of the micelle microenvironment on 2,8-BDF formation was verified via an experiment and molecular dynamics simulation. The organic region of micelle exhibited high hydrogen donation ability, which inhibited 2,8-BDF formation. The results indicated distinct risks of PBDE photolysis in various soil-washing solutions, providing an important reference for solubilizer selection and the application of photolysis on the treatment of soil-washing solutions containing PBDEs. Full article

Polybrominated diphenyl ethers (PBDEs) are synthetic halogen compounds, industrially used as flame retardants in many flammable products. PBDEs are environmentally persistent and bioaccumulative substances that were used from the 1970s and discontinued in the 1990s. PBDEs are present in air, soil, water, and food, where they remain stable for a long time. Chronic exposure to PBDEs is associated with adverse human health effects, including cancer, immunotoxicity, hepatotoxicity, reproductive and metabolic disorders, motor and hormonal impairments, and neurotoxicity, especially in children. It has been demonstrated that PBDE exposure can cause mitochondrial and DNA damage, apoptosis, oxidative stress, epigenetic modifications, and changes in calcium and neurotransmitter levels. Here, we conduct a comprehensive review of the molecular mechanisms of the neurotoxicity of PBDEs using different approaches. We discuss the main neurotransmitter pathways affected by exposure to PBDEs in vitro and in vivo in different mammalian models. Excitatory and inhibitory signaling pathways are the putative target where PBDEs carry out their neurotoxicity. Based on this evidence, environmental PBDEs are considered a risk to human public health and a hazard to biota, underscoring the need for environmental monitoring to mitigate exposure to PBDEs. Full article

Organophosphate flame retardants (OPFRs) have increasingly replaced polybrominated diphenyl ethers (PBDEs) in various consumer products and raw materials, due to regulatory restrictions on PBDEs. However, concerns about the toxicity and environmental persistence of OPFRs are growing. This review summarizes current research on the toxicity of OPFRs, with a focus on New Approach Methodologies (NAMs) that aim to eliminate the need for animal testing. NAMs, including in vitro models, omics technologies, and computational methods, provide valuable insights into the cellular and molecular effects of OPFR exposure. Evidence suggests that OPFRs may disrupt multiple organ systems, including the nervous, hepatic, pulmonary, reproductive, and endocrine systems. Additionally, the metabolic transformation of OPFRs can increase their toxicity, raising concerns about long-term exposure risks. While NAM studies provide valuable insights, further research is needed to refine risk-assessment frameworks and improve our understanding of the long-term effects of OPFR exposure, particularly at concentrations found in the environment. This new knowledge will help develop more accurate regulatory guidelines and ensure the better protection of public and environmental health. Full article

Background: Preeclampsia (PE) is a critical complication of pregnancy that affects 3% to 5% of all pregnancies and has been linked to aberrant placentation, causing severe maternal and fetal illness and death. Objectives: This systematic review aims to elucidate the association of in-utero endocrine-disrupting chemical (EDC) exposure and microRNAs and their imprinted genes from prenatal and maternal circulation of PE patients. Methods: Databases such as PubMed, PubMed Central, ScienceDirect, the Comparative Toxicogenomics Database (CTD), ProQuest, EBSCOhost, and Google Scholar were utilized to search for articles that investigate the relationships between selected EDCs and epigenetic events such as DNA methylation and microRNAs that are associated with PE. Results: A total of 29 studies were included in the database search. Altered expression of microRNAs (miR-15a-5p, miR-142-3p, and miR-185) in the placenta of PE patients was positively associated with the urinary concentration of phthalates and phenols in the development of the disease in the first trimester. EDCs such as phenols, phthalates, perfluoroalkyl substances (PFOAs), polybrominated diphenyl ethers (PBDEs), and organochlorine phosphates (OCPs) have been reported to be associated with hypertensive disorders in pregnancy. miRNA-31, miRNA-144, miRNA-145, miRNA-210, placental specific clusters (C14MC, and C19MC) may be used as possible targets for PE because of their potential roles in the onset and progression of PE. Conclusions: Prenatal EDC exposure, including exposure to BPA, showed association with signaling pathways including estrogen, sFlt-1/PlGF, ErbB, MAPK/ERK, and cholesterol mechanisms with placental hemodynamics. Even low EDC exposures leave altered epigenetic marks throughout gestation, which might cause PE complications. Full article

Polybrominated diphenyl ethers (PBDEs), a type of brominated flame retardant, are of global concern due to their environmental persistence, bioaccumulation, toxicity, and resistance to conventional remediation methods. In this study, the electrochemical reduction of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) with Pd/Metal foam electrodes (Ni, Cu, and Ag) was investigated. The effect of Pd loadings was explored, and the results show that Pd loading enhances the debromination performance, with 15.16%Pd/Ni foam exhibiting the best efficiency, followed by 9.37%Pd/Cu and 10.26%Pd/Ag. The degradation mechanisms for Pd/Ni and Pd/Ag are primarily hydrogen atom transfer, while for Pd/Cu, electron transfer dominates. Among the reduction products, Pd/Ni foam shows the highest debromination capability. The impact of electrolytes, current intensity, and bromination degrees of PBDEs was evaluated for 15.16%Pd/Ni. The results reveal that the presence of electrolytes inhibits BDE-47 degradation; the degradation rate of BDE-47 increases with current density, peaks at 4 mA, and decreases as current rises; and 15.16%Pd/Ni foam can effectively degrade PBDEs with varying bromination levels. Additionally, cycling tests show a decrease in efficiency from 94.3% (first cycle) to 56.58% (fourth cycle), attributed to Pd loss and structural damage. The findings offer valuable insights for developing efficient, sustainable catalytic materials for the electrochemical degradation of PBDEs and other persistent organic pollutants. Full article

The prevalence of hyperthyroidism in cats has been steadily increasing worldwide since the late 1970s. The main cause of feline hyperthyroidism remains unknown. The underlying cause was studied from the viewpoint of the “One Health” concept, which is an approach integrating environmental, animal and human health. Looking at the dietary difference between cats which are carnivores and dogs which appear to be omnivores like humans, there is a possibility that cats take in a comparatively greater amount of endocrine-disrupting chemicals such as polybrominated diphenyl ethers (PBDEs) than dogs and humans via the fish-based food web. PBDEs have been used worldwide as flame retardants since the 1970s. It is considered that PBDEs mimic thyroid-stimulating hormones to cause a thyroid adenoma, which is often active and produces excessive thyroid hormones, resulting in symptomatic hyperthyroidism. The increasing prevalence of feline hyperthyroidism may be associated with Minamata disease that was caused by methyl-mercury contamination in the 1950s. This environmental contamination firstly wreaked havoc as neurological disorders in local cats, and this occurrence was a sign that severe neurological disorders would next develop in large numbers of local people. The prevalence of feline hyperthyroidism may be a sign of what will next emerge in human beings. Full article

Microorganisms play a significant role in biofouling and biocorrosion within the maritime industry. Addressing these challenges requires an innovative and integrated approach utilizing marine natural products with beneficial properties. A comprehensive screening of 173 non-toxic EtOAc and H₂O extracts derived from diverse marine organisms collected in Indonesian waters was conducted using a robust panel of assays. These included antimicrobial tests and classical biosurfactant assays (drop collapse and oil displacement), as well as anti-quorum-sensing (QS) and anti-biofilm assays. These screening efforts identified five active extracts with promising activities. Among these, EtOAc extracts of the marine tunicate Sigilina cf. signifera (0159-22e) and the marine sponge Lamellodysidea herbacea (0194-24c) demonstrated significant anti-biofouling activity against Perna indica and anti-biocorrosion performance (mpy 10.70 ± 0.70 for S. cf. signifera; 7.87 ± 0.86 for L. herbacea; 13.60 ± 1.70 for positive control Tetracorr CI-2915). Further chemical analyses of the active extracts, including LC-HR-MS/MS, MS-based molecular networking, and chemoinformatics, revealed the presence of both known and new bioactive compounds. These included tambjamines and polybrominated diphenyl ethers (PBDEs), which are likely contributors to the observed bioactivities. Subsequent investigations uncovered new anti-QS and anti-biofilm properties in synthetic and natural PBDEs 1–12 previously derived from L. herbacea. Among these, 8 exhibited the most potent anti-QS activity, with an IC₅₀ value of 15 µM, while 4 significantly reduced biofilm formation at a concentration of 1 µM. This study highlights the potential of marine-derived compounds in addressing biofouling and biocorrosion challenges in a sustainable and effective manner. Full article

Polybrominated diphenyl ethers (PBDEs) are natural products with potent antimicrobial and antineoplastic activity. We have previously shown that the polybrominated diphenyl ether bromoxib (4,5,6-tribromo-2-(2′,4′-dibromophenoxy) phenol), isolated from the marine sponge Dysidea species, exhibits a strong cytotoxic potential in leukemia and lymphoma cells by targeting mitochondrial metabolism. Here, using a mass spectrometric thermal proteome profiling (TPP) approach, we observed that bromoxib induces a rapid reduction in the levels of 19 nucleoporins (NUPs) that are part of the nuclear pore complex (NPC). This apparently affected the functionality of the NPC, as evidenced by the bromoxib-mediated inhibition of the nuclear translocation and subsequent gene reporter activity of transcription factors such as nuclear factor of activated T cells (NFAT) and nuclear factor κB (NF-κB). In addition, bromoxib inhibited the nuclear export of the mRNA of the human immunodeficiency virus transactivator of transcription (HIV-Tat) and the subsequent import of the HIV-Tat protein into the nucleus as determined by the decrease in Tat-dependent gene reporter luciferase activity. Inhibition of nuclear mRNA-export also affected expression of the short-lived anti-apoptotic Bcl-2 protein Mcl-1, which has been shown to induce apoptosis. Thus, its ability to target both mitochondrial metabolism and the NPC renders bromoxib a promising anticancer agent. Full article

Current studies have paid extensive attention to the occurrence of brominated flame retardants (BFRs) in aquatic environments; however, there is a lack of exploration of BFRs in ice media in freshwater environments, and there are fewer studies on the distribution patterns and ecological risks of BFRs in different media. In order to fill this gap in the current research status, this study conducted four seasonal samplings in the Songhua River wetland in Northeast China. The distribution and risk of 14 polybrominated diphenyl ethers (PBDEs) and 22 new brominated flame retardants (NBFRs) in water, ice, sediment, and soil were analyzed using liquid–liquid extraction sample pretreatment and gas chromatography–mass spectrometry instrumentation. A total of 18, 5, 8, 19, and 18 BFRs were detected in non-ice-covered water, ice-covered water, ice, sediment, and soil, respectively. NBFRs dominated contaminant concentrations in each medium. Significant correlations were found between BFRs in ice and subglacial water, suggesting that the sources of BFRs in these two media are similar and there is an exchange between them. The ice enrichment factor (IEF) revealed the water–ice distribution mechanism of BFRs, indicating that wetland ice acts as a temporary sink for 2-(Allyloxy)-1,3,5-tribromobenzene (ATE), 1,2-Dibromo-4-(1,2-dibromoethyl)cyclohexane (α-TBECH), 1,2,5,6-Tetrabromocyclooctane (TBCO), and 2-Bromoallyl 2,4,6-tribromophenyl ether (BATE). In order to achieve dynamic equilibrium, the exchange profile of BFRs between water and sediment requires the release of BFRs into water. The risk quotient (RQ) indicated that TBCO in water and ice poses a moderate risk to aquatic organisms, and its potential impact on wetland ecology cannot be ignored. Full article

Background: The primary flame retardants in vehicles, organophosphates (OPEs) and polybrominated diphenyl ethers (PBDEs), volatilize and accumulate in the enclosed vehicle environment, posing potential health risks. Amidst the rising number of vehicles, the scrutiny of persistent organic pollutants like OPEs and PBDEs in vehicles is increasing. This study investigates occupational and nonoccupational population exposure to specific OPEs (TnBP, TBOEP, TEHP, TCEP, TCiPP, TDCiPP, TPhP, EHDPP) and PBDEs (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, BDE-209) in vehicle dust. Methods: Data on OPEs and PBDEs in vehicle dust were sourced from PubMed and Web of Science. We applied PCA and PMF to identify pollutant sources and assessed health risks using the hazard index (HI) and carcinogenic risk (CR) methods. Monte Carlo simulations were conducted for uncertainty analysis, evaluating variable contributions to the results. Results: The predominant OPE in dust samples was TDCiPP (mean value: 4.34 × 10⁴ ng g⁻¹), and the main PBDE was BDE-209 (mean value: 1.52 × 10⁴ ng g⁻¹). Potential sources of OPEs in vehicle dust include polyvinyl chloride (PVC) upholstery, polyurethane foam (PUF) seats, electronics, carpet wear, hydraulic oil, and plastic wear in the brake system. PBDE sources likely include automotive parts, PVC upholstery, seats, carpets, and electronics. The 90th percentile HI and CR values for occupational and nonoccupational populations exposed to OPEs and PBDEs indicate that the noncarcinogenic and carcinogenic risks are relatively low. A sensitivity analysis showed that the pollutant concentration, time in the vehicle, exposure frequency, and duration significantly influence health risks. Conclusions: The health risks to both occupational and nonoccupational populations from exposure to OPEs and PBDEs in vehicle dust are relatively low. Full article

Polybrominated diphenyl ethers (PBDEs), commonly used as synthetic flame retardants, are present in a variety of consumer products, including electronics, polyurethane foams, textiles, and building materials. Initial evidence from epidemiological and experimental studies suggests that maternal PBDE exposure may be associated with a higher BMI in children, with disturbance of energy metabolism and an increased risk of Type 2 diabetes. However, the causality between early exposure to real-life PBDE concentrations and increased weight as well as mechanisms underlying impaired metabolic pathways in the offspring remain elusive. Here, using a mouse model we examined the effect of maternal exposure to 2,2′,4,4′-tetrabrominated diphenyl ether (BDE-47), the most abundant congener in human samples, on offspring weight gain and energy homeostasis using a mouse model. Maternal exposure to BDE-47 at low dose resulted in weight gain in female offspring together with an impaired glucose and insulin tolerance in both female and male mice. In vitro and in vivo data suggest increased adipogenesis induced by BDE-47, possibly mediated by DNA hypermethylation. Furthermore, mRNA data suggest that neuronal dysregulation of energy homeostasis, driven via a disturbed leptin signaling may contribute to the observed weight gain as well as impaired insulin and glucose tolerance. Full article

Human influence on Antarctic marine ecosystems is a growing concern, despite limited information being available. This study investigated the coastal meiofauna and environmental parameters of 10 locations, 4 of which served as reference points (OB1, OB2, OB3, and McGrady) and 6 which were impacted by different levels of human activity in the past and present (Wharf, Wilkes, BBIN, BBMID, BBOUT, and Shannon) in East Antarctica. Environmental variables such as metals, total petroleum hydrocarbons (TPHs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), grain size, organic matter content, and nutrients were measured for analysis. Locations close to human activities showed higher concentrations of pollutants (metals, TPHs, PBDEs, PCBs) and greater variations in meiofauna diversity compared to the reference sites (OB1, OB2, OB3, and McGrady). In the area impacted by the Casey Station waste dump (Brown Bay), the meiofauna community at the location furthest from the pollution (BBOUT) source exhibited greater diversity compared to the closest location (BBIN). In addition to metals and TPHs, particle size was also correlated with community patterns, with finer sediments associated with more impacted sites, facilitating the accumulation of toxic compounds. These results contribute to the understanding of the role and impact of pollutants on meiofauna biodiversity in Antarctic coastal ecosystems. Full article

Flame retardants have been shown to cause widespread physiological effects, in particular on endocrine organs such as the thyroid. This review aims to provide an overview of the literature on the association between flame retardants and thyroid function within humans. A search in the National Library of Medicine and National Institutes of Health PubMed database through January 2024 yielded 61 studies that met the inclusion criteria. The most frequently analyzed flame retardants across all thyroid hormones were polybrominated diphenyl ethers (PBDEs), in particular BDE-47 and BDE-99. Ten studies demonstrated exclusively positive associations between flame retardants and thyroid stimulating hormone (TSH). Six studies demonstrated exclusively negative associations between flame retardants and TSH. Twelve studies demonstrated exclusively positive associations for total triiodothyronine (tT3) and total thyroxine (tT4). Five and eight studies demonstrated exclusively negative associations between flame retardants and these same thyroid hormones, respectively. The effect of flame retardants on thyroid hormones is heterogeneous; however, the long-term impact warrants further investigation. Vulnerable populations, including indigenous people, individuals working at e-waste sites, firefighters, and individuals within certain age groups, such as children and elderly, are especially critical to be informed of risk of exposure. Full article

Polybrominated diphenyl ethers (PBDEs) have been used for many years as flame retardants. Due to their physicochemical and toxicological properties, they are considered to be persistent organic pollutants (POPs). BDE-209 is the main component of deca-BDE, the one PBDE commercial mixture currently approved for use in the European Union. The aim of this study was to analyse BDE-209 in surface soil samples from Warsaw and surrounding areas (Poland) as an indicator of environmental pollution with PBDEs, and to characterise the associated health risk. A total of 40 samples were analysed using gas chromatography with electron capture detection (GC-µECD). Concentrations of BDE-209 in soil ranged from 0.4 ng g⁻¹ d.w. (limit of quantification) to 158 ng g⁻¹ d.w. Overall, 52.5% of results were above the method’s limit of quantification. The highest levels were found at several locations with heavy traffic and in the vicinity of a CHP plant in the city. The lowest concentrations were observed in most of the samples collected from low industrialized or green areas (<0.4 to 1.68 ng g⁻¹ d.w.). Exposure to BDE-209 was estimated for one of the most sensitive populations, i.e., young children. The following exposure routes were selected: oral and dermal. No risk was found to young children’s health. Full article