1
|
Lan Y, Gao X, Xu H, Li M. 20 years of polybrominated diphenyl ethers on toxicity assessments. WATER RESEARCH 2024; 249:121007. [PMID: 38096726 DOI: 10.1016/j.watres.2023.121007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 11/17/2023] [Accepted: 12/09/2023] [Indexed: 01/03/2024]
Abstract
Polybrominated diphenyl ethers (PBDEs) serve as brominated flame retardants which continue to receive considerable attention because of their persistence, bioaccumulation, and potential toxicity. Although PBDEs have been restricted and phased out, large amounts of commercial products containing PBDEs are still in use and discarded annually. Consequently, PBDEs added to products can be released into our surrounding environments, particularly in aquatic systems, thus posing great risks to human health. Many studies and reviews have described the possible toxic effects of PBDEs, while few studies have comprehensively summarized and analyzed the global trends of their toxicity assessment. Therefore, this study utilizes bibliometrics to evaluate the worldwide scientific output of PBDE toxicity and analyze the hotspots and future trends of this field. Firstly, the basic information including the most contributing countries/institutions, journals, co-citations, influential authors, and keywords involved in PBDE toxicity assessment will be visualized. Subsequently, the potential toxicity of PBDE exposure to diverse systems, such as endocrine, reproductive, neural, and gastrointestinal tract systems, and related toxic mechanisms will be discussed. Finally, we conclude this review by outlining the current challenges and future perspectives in environmentally relevant PBDE exposure, potential carriers for PBDE transport, the fate of PBDEs in the environment and human bodies, advanced stem cell-derived organoid models for toxicity assessment, and promising omics technologies for obtaining toxic mechanisms. This review is expected to offer systematical insights into PBDE toxicity assessments and facilitate the development of PBDE-based research.
Collapse
Affiliation(s)
- Yingying Lan
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China; State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Burn Research, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Xue Gao
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400030, China
| | - Haiwei Xu
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China.
| | - Minghui Li
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China; Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400030, China.
| |
Collapse
|
2
|
Gustafsson J, Legradi J, Lamoree MH, Asplund L, Leonards PEG. Metabolite alterations in zebrafish embryos exposed to hydroxylated polybrominated diphenyl ethers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159269. [PMID: 36208744 DOI: 10.1016/j.scitotenv.2022.159269] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/24/2022] [Accepted: 10/02/2022] [Indexed: 06/16/2023]
Abstract
Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) are formed by metabolism from the flame retardants polybrominated diphenyl ethers (PBDEs). In the aquatic environment, they are also produced naturally. OH-PBDEs are known for their potential to disrupt energy metabolism, the endocrine system, and the nervous system. This is the first study focusing on the effects of OH-PBDEs at the metabolite level in vivo. The aim of the current study was to investigate the metabolic effects of exposure to OH-PBDEs using metabolomics, and to identify potential biomarker(s) for energy disruption of OH-PBDEs. Zebrafish (Danio rerio) embryos were exposed to two different concentrations of 6-OH-BDE47 and 6-OH-BDE85 and a mixture of these two compounds. In total, 342 metabolites were annotated and 79 metabolites were affected in at least one exposure. Several affected metabolites, e.g. succinic acid, glutamic acid, glutamine, tyrosine, tryptophan, adenine, and several fatty acids, could be connected to known toxic mechanisms of OH-PBDEs. Several phospholipids were strongly up-regulated with up to a six-fold increase after exposure to 6-OH-BDE47, a scarcely described effect of OH-PBDEs. Based on the observed metabolic effects, a possible connection between disruption of the energy metabolism, neurotoxicity and potential immunotoxicity of OH-PBDEs was suggested. Single compound exposures to 6-OH-BDE47 and 6-OH-BDE85 showed little overlap in the affected metabolites. This shows that compounds of similar chemical structure can induce different metabolic effects, possibly relating to their different toxic mechanisms. There were inter-concentration differences in the metabolic profiles, indicating that the metabolic effects were concentration dependent. After exposure to the mixture of 6-OH-BDE47 and 6-OH-BDE85, a new metabolic profile distinct from the profiles obtained from the single compounds was observed. Succinic acid was up-regulated at the highest, but still environmentally relevant, concentration of 6-OH-BDE47, 6-OH-BDE85, and the mixture. Therefore, succinic acid is suggested as a potential biomarker for energy disruption of OH-PBDEs.
Collapse
Affiliation(s)
- Johan Gustafsson
- Department of Environmental Science, Stockholm University, Stockholm, Sweden; Amsterdam Institute for Life and Environment, Vrije Universiteit, Amsterdam, the Netherlands.
| | - Jessica Legradi
- Amsterdam Institute for Life and Environment, Vrije Universiteit, Amsterdam, the Netherlands
| | - Marja H Lamoree
- Amsterdam Institute for Life and Environment, Vrije Universiteit, Amsterdam, the Netherlands
| | - Lillemor Asplund
- Department of Environmental Science, Stockholm University, Stockholm, Sweden
| | - Pim E G Leonards
- Amsterdam Institute for Life and Environment, Vrije Universiteit, Amsterdam, the Netherlands
| |
Collapse
|
3
|
Contamination Status of Pet Cats in Thailand with Organohalogen Compounds (OHCs) and Their Hydroxylated and Methoxylated Derivatives and Estimation of Sources of Exposure to These Contaminants. Animals (Basel) 2022; 12:ani12243520. [PMID: 36552442 PMCID: PMC9774237 DOI: 10.3390/ani12243520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/09/2022] [Accepted: 12/09/2022] [Indexed: 12/15/2022] Open
Abstract
In this study, we analyzed serum samples of pet cats from Thailand and estimated the contribution to organohalogen compounds (OHCs) exposure through cat food and house dust intake. BDE-209 was predominant in cat sera and accounted for 76% of all polybrominated diphenyl ethers (PBDEs). Decabromodiphenyl ether (BDE-209) is a major contaminant in dry cat food and house dust, which has been estimated to be a source of exposure for Thai pet cats. BDE-209 is a major contaminant of OHCs in dry cat food and house dust, which was estimated to be a source of exposure for Thai pet cats. On the other hand, the level of contamination by PCBs was lower than in other countries. Analysis of pet foods suggested that BDE-209 in pet cat serum was attributable to the consumption of dry cat food. On the other hand, house dust also contained high concentrations of BDE-209. Thus, high levels of BDE-209 in pet cat sera can be attributed to the consumption of dry cat food and house dust. These results suggest that pet cats are routinely exposed to non-negligible levels of OHCs.
Collapse
|
4
|
Hombrecher K, Quass U, Sievering S, Schöppe A, Rauchfuss K. Contamination of food crops by unintentionally released PCB 47, PCB 51 and PCB 68 in the vicinity of silicone production sites and their relevance for human health assessment. CHEMOSPHERE 2022; 308:136392. [PMID: 36096305 DOI: 10.1016/j.chemosphere.2022.136392] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 09/05/2022] [Accepted: 09/06/2022] [Indexed: 06/15/2023]
Abstract
Since it was shown that silicone rubber production can unintentionally release PCBs, these production sites have become a focus of investigation. The use of the cross-linking agent bis(2,4)-dichlorobenzoylperoxide (2,4-DCBP) can lead to emissions of the PCB congeners PCB 47, PCB 51 and PCB 68 into the environment and cause their accumulation e. g. in food crops. To determine the presence and extent of this uptake, we used the newly developed method dandelion screening. Samples were taken from wild dandelion plants near nine production sites in North Rhine-Westphalia, Germany, and analysed for PCBs. In some cases, the regional orientation values for the maximum background level (OMB) were exceeded by up to nine times. Overall, background levels were exceeded at seven of the nine sites investigated and mitigation measures were initiated at the production sites. In order to validate the dandelion screening results, kale was exposed, which allowed for a health assessment. A wide-ranging consumption recommendation was then issued in four out of nine study areas. At this point in the investigations, risk reduction measures had already been implemented at all production sites investigated, so it can be assumed that the exposures at sites not yet in focus are significantly greater. This is a globally relevant problem, as 2,4-DCBP is used in many countries.
Collapse
Affiliation(s)
- Katja Hombrecher
- North Rhine-Westphalia State Agency for Nature, Environment and Consumer Protection (LANUV NRW), Wallneyer Str. 6, Essen, 45133, Germany.
| | - Ulrich Quass
- North Rhine-Westphalia State Agency for Nature, Environment and Consumer Protection (LANUV NRW), Wallneyer Str. 6, Essen, 45133, Germany
| | - Silvia Sievering
- North Rhine-Westphalia State Agency for Nature, Environment and Consumer Protection (LANUV NRW), Wallneyer Str. 6, Essen, 45133, Germany
| | - Angelika Schöppe
- North Rhine-Westphalia State Agency for Nature, Environment and Consumer Protection (LANUV NRW), Wallneyer Str. 6, Essen, 45133, Germany
| | - Knut Rauchfuss
- North Rhine-Westphalia State Agency for Nature, Environment and Consumer Protection (LANUV NRW), Wallneyer Str. 6, Essen, 45133, Germany
| |
Collapse
|
5
|
Kaifie A, Esser A, Ziegler P, Kraus T, Rauchfuss K, Schettgen T. Environmental release of non-Aroclor polychlorinated biphenyls by a silicone rubber production site did not lead to elevated plasma levels in the nearby population. Int J Hyg Environ Health 2022; 245:114028. [PMID: 36041276 DOI: 10.1016/j.ijheh.2022.114028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/19/2022] [Accepted: 08/19/2022] [Indexed: 10/15/2022]
Abstract
In 2019, high concentrations of the non-Aroclor PCB congeners 47, 51, and 68 were released by a silicone rubber production site in North-Rhine Westphalia, Germany. Local authorities announced a consumption alert for home-grown fruits and vegetables for the affected area which led to a great level of insecurity among the population regarding potential health effects. The aim of study was to determine the plasma levels of the non-Aroclor congeners and the six ndl-indicator congeners (PCB 28, 52, 101, 138, 153, 180) in children and women with child-bearing potential living close to the production site. Altogether n = 111 participants, with n = 73 female adults and n = 38 children were included in this analysis. For the non-Aroclor-PCBs as well as the lower-clorinated ndl-indicator PCBs 28, 52, and 101, the median plasma concentrations were below the LOQ. Only one adult showed an elevated PCB 47 value. In conclusion, no elevated plasma levels could be detected for PCB 47, 51, or 68 in the nearby population of the silicone-rubber production site. However, our study was highly important for risk characterisation as well as risk communication.
Collapse
Affiliation(s)
- Andrea Kaifie
- Institute for Occupational, Social, and Environmental Medicine, Medical Faculty, RWTH Aachen University, Germany.
| | - André Esser
- Institute for Occupational, Social, and Environmental Medicine, Medical Faculty, RWTH Aachen University, Germany
| | - Patrick Ziegler
- Institute for Occupational, Social, and Environmental Medicine, Medical Faculty, RWTH Aachen University, Germany
| | - Thomas Kraus
- Institute for Occupational, Social, and Environmental Medicine, Medical Faculty, RWTH Aachen University, Germany
| | - Knut Rauchfuss
- North Rhine-Westphalia State Agency for Nature, Environment and Consumer Protection, Recklinghausen, Germany
| | - Thomas Schettgen
- Institute for Occupational, Social, and Environmental Medicine, Medical Faculty, RWTH Aachen University, Germany
| |
Collapse
|
6
|
Chen W, Hou X, Mao X, Jiao S, Wei L, Wang Y, Liu J, Jiang G. Biotic and Abiotic Transformation Pathways of a Short-Chain Chlorinated Paraffin Congener, 1,2,5,6,9,10-C 10H 16Cl 6, in a Rice Seedling Hydroponic Exposure System. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:9486-9496. [PMID: 35622943 DOI: 10.1021/acs.est.2c01119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In this work, a typical congener of short-chain chlorinated paraffins (SCCPs) with six chlorine atoms (CP-4, 1,2,5,6,9,10-C10H16Cl6, 250 ng/mL) was selected to elaborate the comprehensive environmental transformation of SCCPs in rice seedling exposure system. CP-4 was quickly absorbed, translocated, and phytovolatilized by seedlings with a small quality of CP-4 (5.81-36.5 ng) being detected in the gas phase. Only 21.4 ± 1.6% of an initial amount (10,000 ng) of CP-4 remained in the exposure system at the end of exposure. Among the transformed CP-4, some were attributed to the degradation of the rhizosphere microorganism (9.1 ± 5.8%), root exudates (2.2 ± 4.2%), and abiotic transformation (3.0 ± 2.8%) that were proved by several transformation products found in the root exudate exposure groups and unplanted controls, and a majority was phytotransformed by rice seedlings. Here, 61 products were determined through complex transformation pathways, including multihydroxylation, -HCl elimination, dechlorination, acetylation, sulfation, glycosylation, and amide acid conjugation. The acetylated and amide acid conjugates of CPs were first observed. Phase I and Phase II phytometabolic reactions of CPs were found intertwining. These findings demonstrate that multiactive transformation reactions contribute to the overlook of CPs accumulated in plants and are helpful for the environmental and health risk assessments of SCCPs in agricultural plants.
Collapse
Affiliation(s)
- Weifang Chen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xingwang Hou
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaowei Mao
- School of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Suning Jiao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Linfeng Wei
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yaotian Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
- Research Center for Analytical Sciences, Department of Chemistry, College of Sciences, Northeastern University, Shenyang 110819, China
| | - Jiyan Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
- School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310000, China
| | - Guibin Jiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
- School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310000, China
| |
Collapse
|
7
|
Schettgen T, Esser A, Alt A, Randerath I, Kraus T, Ziegler P. Decomposition Products of the Initiator Bis(2,4-dichlorobenzoyl)peroxide in the Silicone Industry: Human Biomonitoring in Plasma and Urine of Workers. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:8518-8527. [PMID: 35671459 DOI: 10.1021/acs.est.2c01530] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Bis(2,4-dichlorobenzoyl)peroxide (2,4-DCBP) is used as an initiator for silicone rubber production. During hot curing, 2,4-DCBP decomposes into 2,4-dichlorobenzoic acid, 1,3-dichlorobenzene, and the polychlorinated biphenyl (PCB) congeners PCB-47, PCB-51, and PCB-68. The extent of occupational exposure to these decomposition products has not been investigated yet. We determined for the first time the corresponding internal exposure of employees (n = 104) of a German silicone rubber facility by human biomonitoring in plasma and urine. Collected samples were investigated by gas chromatography/mass spectrometry for levels of PCBs in plasma and by liquid chromatography/tandem mass spectrometry for urinary post-shift levels of 2,4-dichlorobenzoic acid (2,4-DCBA) and the metabolites 3,5-dichlorocatechol (3,5-DCK), 2,4-dichlorophenol (2,4-DCP), and 3,5-dichlorophenol (3,5-DCP). PCB-47 and PCB-68 levels correlated significantly and were found in >97% of all samples with maximum values of 4.43 and 0.77 μg/L, respectively. 2,4-DCBA, 3,5-DCK, 2,4-DCP, and 3,5-DCP were quantified in >80% of all urine samples with maximum levels of 1.46; 26.92; 7.68; and 0.39 mg/L, respectively. There is a considerable uptake of decomposition products of 2,4-DCBP in workers of a silicone rubber facility, affecting employees in all work areas. Individual levels depended on the work task. Considering the carcinogenic potential of PCBs, the workers' additional exposure to PCB-47 and PCB-68 might be of concern.
Collapse
Affiliation(s)
- Thomas Schettgen
- Institute for Occupational, Social and Environmental Medicine, Medical Faculty, RWTH Aachen University, Aachen 52074, Germany
| | - André Esser
- Institute for Occupational, Social and Environmental Medicine, Medical Faculty, RWTH Aachen University, Aachen 52074, Germany
| | - Anne Alt
- Institute for Occupational, Social and Environmental Medicine, Medical Faculty, RWTH Aachen University, Aachen 52074, Germany
| | - Isabella Randerath
- Institute for Occupational, Social and Environmental Medicine, Medical Faculty, RWTH Aachen University, Aachen 52074, Germany
| | - Thomas Kraus
- Institute for Occupational, Social and Environmental Medicine, Medical Faculty, RWTH Aachen University, Aachen 52074, Germany
| | - Patrick Ziegler
- Institute for Occupational, Social and Environmental Medicine, Medical Faculty, RWTH Aachen University, Aachen 52074, Germany
| |
Collapse
|
8
|
Schettgen T, Esser A, Kraus T, Ziegler P. Plasma levels of unintentionally produced non-Aroclor polychlorinated biphenyl (PCB) congeners in workers from the silicone rubber industry. CHEMOSPHERE 2022; 291:132722. [PMID: 34718009 DOI: 10.1016/j.chemosphere.2021.132722] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/18/2021] [Accepted: 10/25/2021] [Indexed: 06/13/2023]
Abstract
The unintentional release of non-Aroclor-PCBs 47, PCB 68 and PCB 51 by a silicone manufacturing company in North Rhine-Westphalia, Germany, due to the use of bis-(2,4-dichlorobenzoyl)peroxide (2,4-DCBP) as an initiator has raised serious concerns about the possible uptake of these congeners by workers in silicone rubber production. We have conducted a pilot study in Germany to quantify these congeners in plasma samples of employees working in and handling silicone rubber during production and electrical cable manufacturing. A total of 117 plasma samples were collected from workers in 7 companies and 84 plasma samples from control subjects not working in silicone industry. PCB 47 and PCB 68 were detected in plasma above the limit of quantification (0.01 μg/L) in 84% and 66% of the silicone industry workers, respectively, whereas both congeners were undetectable in plasma of the control group. The maximum levels for PCB 47 were 2.56 μg/L and for PCB 68 were 0.42 μg/L. PCB 51 could not be determined in any plasma sample. Plasma samples of workers making electric cables had in general lower levels than those from workers making silicone rubber. Due to the high persistence of PCBs and the poorly defined toxicological properties of PCB 47 and PCB 68, a replacement of 2,4-DCBP as initiator in silicone rubber production should be considered. Given the large market for silicone products, our results might have a global impact on silicone industry.
Collapse
Affiliation(s)
- Thomas Schettgen
- Institute for Occupational, Social and Environmental Medicine, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, D-52074, Aachen, Germany.
| | - André Esser
- Institute for Occupational, Social and Environmental Medicine, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, D-52074, Aachen, Germany
| | - Thomas Kraus
- Institute for Occupational, Social and Environmental Medicine, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, D-52074, Aachen, Germany
| | - Patrick Ziegler
- Institute for Occupational, Social and Environmental Medicine, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, D-52074, Aachen, Germany
| |
Collapse
|
9
|
Qian B, Zen Z, Zheng Z, Wang C, Song J. A preliminary study on the mechanism of the neurosteroid-mediated ionotropic receptor dysfunction in neurodevelopmental toxicity induced by decabromodiphenyl ether. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 217:112198. [PMID: 33862428 DOI: 10.1016/j.ecoenv.2021.112198] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 03/19/2021] [Accepted: 03/25/2021] [Indexed: 06/12/2023]
Abstract
The mechanism of neurodevelopmental toxicity of decabromodiphenyl ether (BDE209) remains unclear. Recent evidence suggests that neurosteroids disorders play a vital role in BDE209 induced-neurodevelopmental toxicity. To explore the mechanism of it, pregnant ICR mice were orally gavaged with 0, 225, and 900 mg kg-1 BDE209 for about 42 days. Spatial learning and memory abilities of offspring were tested on postnatal day (PND) 21. Offspring were euthanized at PND26, the neuronal structure, neurosteroids level, and related proteins including neurosteroids synthase, ionotropic receptors and cAMP-response element binding protein (CREB) pathway were evaluated, as well as Ca2+ concentration and the mitochondrial membrane potential (Mmp). Our results showed that BDE209 impaired learning and memory abilities and disrupted neuronal structure. Meanwhile, BDE209 decreased the pregnenolone (PREG), dehydroepiandrosterone (DHEA), progesterone (PROG) and allopregnanolone (ALLO) levels in the serum and brain, as well as the mRNA and protein levels of cholesterol-side-chain cleavage enzyme (P450scc), steroid 17α-hy-droxylase (P450C17), 3β-hydroxysteroid dehydrogenase (3β-HSD) and steroid 5α-reductase of type I (5α-R) in the hippocampi. Also, BDE209 suppressed mRNA and protein levels of NR1, NR2A and NR2B subunits of the N-methyl-D-aspartic acid receptor (NMDAR) and α1 subunit of the Gamma-amino butyric acid A receptor (GABAAR), but increased the levels of β2 and γ2 subunits of the GABAAR in the hippocampi. Moreover, BDE209 increased the Ca2+ concentration and phosphorylation extracellular regulated protein kinases (P-ERK) 1/2 level, but decreased the P-CREB and Mmp level in the hippocampi. These results indicate that BDE209 exposure during pregnancy and lactation is possible to affect learning and memory formation of offspring by the neurosteroid-mediated ionotropic receptors dysfunction.
Collapse
Affiliation(s)
- Bo Qian
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, Fujian 361102, People's Republic of China; Department of Occupational and Environmental Health, Guilin Medical University, Guilin, Guangxi 541004, People's Republic of China; Guangxi Colleges and University Key Laboratory of Preventive Medicine, Guilin Medical University, Guilin, Guangxi 541004, People's Republic of China
| | - Zeng Zen
- Department of Nutrition and Food Hygiene, Guilin Medical University, Guilin, Guangxi 541004, People's Republic of China; Guangxi Colleges and University Key Laboratory of Preventive Medicine, Guilin Medical University, Guilin, Guangxi 541004, People's Republic of China
| | - Zhaoxuan Zheng
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, Fujian 361102, People's Republic of China
| | - Chengqiang Wang
- Department of Occupational and Environmental Health, Guilin Medical University, Guilin, Guangxi 541004, People's Republic of China; Guangxi Colleges and University Key Laboratory of Preventive Medicine, Guilin Medical University, Guilin, Guangxi 541004, People's Republic of China
| | - Jiale Song
- Department of Nutrition and Food Hygiene, Guilin Medical University, Guilin, Guangxi 541004, People's Republic of China; Guangxi Colleges and University Key Laboratory of Preventive Medicine, Guilin Medical University, Guilin, Guangxi 541004, People's Republic of China.
| |
Collapse
|
10
|
Latchney SE, Majewska AK. Persistent organic pollutants at the synapse: Shared phenotypes and converging mechanisms of developmental neurotoxicity. Dev Neurobiol 2021; 81:623-652. [PMID: 33851516 DOI: 10.1002/dneu.22825] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 02/27/2021] [Accepted: 04/09/2021] [Indexed: 12/18/2022]
Abstract
The developing nervous system is sensitive to environmental and physiological perturbations in part due to its protracted period of prenatal and postnatal development. Epidemiological and experimental studies link developmental exposures to persistent organic pollutants (POPs) including polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, polybrominated diphenyl ethers, and benzo(a)pyrene to increased risk for neurodevelopmental disorders in children. Mechanistic studies reveal that many of the complex cellular processes that occur during sensitive periods of rapid brain development are cellular targets for developmental neurotoxicants. One area of research interest has focused on synapse formation and plasticity, processes that involve the growth and retraction of dendrites and dendritic spines. For each chemical discussed in this review, we summarize the morphological and electrophysiological data that provide evidence that developmental POP exposure produces long-lasting effects on dendritic morphology, spine formation, glutamatergic and GABAergic signaling systems, and synaptic transmission. We also discuss shared intracellular mechanisms, with a focus on calcium and thyroid hormone homeostasis, by which these chemicals act to modify synapses. We conclude our review highlighting research gaps that merit consideration when characterizing synaptic pathology elicited by chemical exposure. These gaps include low-dose and nonmonotonic dose-response effects, the temporal relationship between dendritic growth, spine formation, and synaptic activity, excitation-inhibition balance, hormonal effects, and the need for more studies in females to identify sex differences. By identifying converging pathological mechanisms elicited by POP exposure at the synapse, we can define future research directions that will advance our understanding of these chemicals on synapse structure and function.
Collapse
Affiliation(s)
- Sarah E Latchney
- Department of Biology, St. Mary's College of Maryland, St. Mary's City, MD, USA.,Department of Neuroscience, Del Monte Institute for Neuroscience, University of Rochester Medical Center, Rochester, NY, USA
| | - Ania K Majewska
- Department of Neuroscience, Del Monte Institute for Neuroscience, University of Rochester Medical Center, Rochester, NY, USA.,Center for Visual Science, University of Rochester Medical Center, Rochester, NY, USA
| |
Collapse
|
11
|
Wei J, Xiang L, Cai Z. Emerging environmental pollutants hydroxylated polybrominated diphenyl ethers: From analytical methods to toxicology research. MASS SPECTROMETRY REVIEWS 2021; 40:255-279. [PMID: 32608069 DOI: 10.1002/mas.21640] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/13/2020] [Accepted: 05/23/2020] [Indexed: 06/11/2023]
Abstract
Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) are of particular concern due to their ubiquitous distribution and adverse health effects. Significant progress has been made in the characterization of OH-PBDEs by using mass spectrometry (MS). In this review, we summarize applications of MS-based techniques in detection, environmental and biota distribution, and potential health risk effects, hoping to unfold an overall picture on account of current knowledge of OH-PBDEs. The analytical methodologies are discussed from sample pretreatment to MS analysis. The methods including gas chromatography-MS (GC-MS), liquid chromatography-MS (LC-MS), and ion mobility spectrometry-MS (IMS-MS) are discussed. GC-MS is the most frequently adopted method in the analysis of OH-PBDEs due to its excellent chromatographic resolution, high sensitivity, and strong ability for unknown identification. LC-MS has been widely used for its high sensitivity and capability of direct analysis. As a newly developed technique, IMS-MS provides high specificity, which greatly facilitates the identification of isomers. OH-PBDEs pervasively existed in both abiotic and biotic samples, including humans, animals, and environmental matrices. Multiple adverse health effects have been reported, such as thyroid hormone disruption, estrogen effects, and neurotoxicity. The reported potential pathological mechanisms are also reviewed. Additionally, MS-based metabolomics, lipidomics, and proteomics have been shown as promising tools to unveil the molecular mechanisms of the toxicity of OH-PBDEs. © 2020 John Wiley & Sons Ltd. Mass Spec Rev.
Collapse
Affiliation(s)
- Juntong Wei
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong SAR, China
| | - Li Xiang
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong SAR, China
| | - Zongwei Cai
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong SAR, China
| |
Collapse
|
12
|
Gao J, Zhang H, Xiong P, Yan X, Liao C, Jiang G. Application of electrophysiological technique in toxicological study: From manual to automated patch-clamp recording. Trends Analyt Chem 2020. [DOI: 10.1016/j.trac.2020.116082] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
|
13
|
Tukker AM, Bouwman LMS, van Kleef RGDM, Hendriks HS, Legler J, Westerink RHS. Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) acutely affect human α 1β 2γ 2L GABA A receptor and spontaneous neuronal network function in vitro. Sci Rep 2020; 10:5311. [PMID: 32210279 PMCID: PMC7093421 DOI: 10.1038/s41598-020-62152-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 03/04/2020] [Indexed: 11/28/2022] Open
Abstract
Concerns about the neurotoxic potential of polyfluoroalkyl substances (PFAS) such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) increase, although their neurotoxic mechanisms of action remain debated. Considering the importance of the GABAA receptor in neuronal function, we investigated acute effects of PFAS on this receptor and on spontaneous neuronal network activity. PFOS (Lowest Observed Effect Concentration (LOEC) 0.1 µM) and PFOA (LOEC 1 µM) inhibited the GABA-evoked current and acted as non-competitive human GABAA receptor antagonists. Network activity of rat primary cortical cultures increased following exposure to PFOS (LOEC 100 µM). However, exposure of networks of human induced pluripotent stem cell (hiPSC)-derived neurons decreased neuronal activity. The higher sensitivity of the α1β2γ2L GABAA receptor for PFAS as compared to neuronal networks suggests that PFAS have additional mechanisms of action, or that compensatory mechanisms are at play. Differences between rodent and hiPSC-derived neuronal networks highlight the importance of proper model composition. LOECs for PFAS on GABAA receptor and neuronal activity reported here are within or below the range found in blood levels of occupationally exposed humans. For PFOS, LOECs are even within the range found in human serum and plasma of the general population, suggesting a clear neurotoxic risk.
Collapse
Affiliation(s)
- Anke M Tukker
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands
| | - Lianne M S Bouwman
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands
| | - Regina G D M van Kleef
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands
| | - Hester S Hendriks
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands
| | - Juliette Legler
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands
| | - Remco H S Westerink
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands.
| |
Collapse
|
14
|
Klocke C, Sethi S, Lein PJ. The developmental neurotoxicity of legacy vs. contemporary polychlorinated biphenyls (PCBs): similarities and differences. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:8885-8896. [PMID: 31713823 PMCID: PMC7220795 DOI: 10.1007/s11356-019-06723-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 10/07/2019] [Indexed: 05/11/2023]
Abstract
Although banned from production for decades, PCBs remain a significant risk to human health. A primary target of concern is the developing brain. Epidemiological studies link PCB exposures in utero or during infancy to increased risk of neuropsychiatric deficits in children. Nonclinical studies of legacy congeners found in PCB mixtures synthesized prior to the ban on PCB production suggest that non-dioxin-like (NDL) congeners are predominantly responsible for the developmental neurotoxicity associated with PCB exposures. Mechanistic studies suggest that NDL PCBs alter neurodevelopment via ryanodine receptor-dependent effects on dendritic arborization. Lightly chlorinated congeners, which were not present in the industrial mixtures synthesized prior to the ban on PCB production, have emerged as contemporary environmental contaminants, but there is a paucity of data regarding their potential developmental neurotoxicity. PCB 11, a prevalent contemporary congener, is found in the serum of children and their mothers, as well as in the serum of pregnant women at increased risk for having a child diagnosed with a neurodevelopmental disorder (NDD). Recent data demonstrates that PCB 11 modulates neuronal morphogenesis via mechanisms that are convergent with and divergent from those implicated in the developmental neurotoxicity of legacy NDL PCBs. This review summarizes these data and discusses their relevance to adverse neurodevelopmental outcomes in humans.
Collapse
Affiliation(s)
- Carolyn Klocke
- Department of Molecular Biosciences, University of California, Davis School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| | - Sunjay Sethi
- Department of Molecular Biosciences, University of California, Davis School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA.
| |
Collapse
|
15
|
Klocke C, Lein PJ. Evidence Implicating Non-Dioxin-Like Congeners as the Key Mediators of Polychlorinated Biphenyl (PCB) Developmental Neurotoxicity. Int J Mol Sci 2020; 21:E1013. [PMID: 32033061 PMCID: PMC7037228 DOI: 10.3390/ijms21031013] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 01/31/2020] [Accepted: 02/02/2020] [Indexed: 12/15/2022] Open
Abstract
Despite being banned from production for decades, polychlorinated biphenyls (PCBs) continue to pose a significant risk to human health. This is due to not only the continued release of legacy PCBs from PCB-containing equipment and materials manufactured prior to the ban on PCB production, but also the inadvertent production of PCBs as byproducts of contemporary pigment and dye production. Evidence from human and animal studies clearly identifies developmental neurotoxicity as a primary endpoint of concern associated with PCB exposures. However, the relative role(s) of specific PCB congeners in mediating the adverse effects of PCBs on the developing nervous system, and the mechanism(s) by which PCBs disrupt typical neurodevelopment remain outstanding questions. New questions are also emerging regarding the potential developmental neurotoxicity of lower chlorinated PCBs that were not present in the legacy commercial PCB mixtures, but constitute a significant proportion of contemporary human PCB exposures. Here, we review behavioral and mechanistic data obtained from experimental models as well as recent epidemiological studies that suggest the non-dioxin-like (NDL) PCBs are primarily responsible for the developmental neurotoxicity associated with PCBs. We also discuss emerging data demonstrating the potential for non-legacy, lower chlorinated PCBs to cause adverse neurodevelopmental outcomes. Molecular targets, the relevance of PCB interactions with these targets to neurodevelopmental disorders, and critical data gaps are addressed as well.
Collapse
Affiliation(s)
| | - Pamela J. Lein
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA;
| |
Collapse
|
16
|
Morris AD, Letcher RJ, Dyck M, Chandramouli B, Cosgrove J. Concentrations of legacy and new contaminants are related to metabolite profiles in Hudson Bay polar bears. ENVIRONMENTAL RESEARCH 2019; 168:364-374. [PMID: 30384230 DOI: 10.1016/j.envres.2018.10.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 09/24/2018] [Accepted: 10/07/2018] [Indexed: 06/08/2023]
Abstract
There are very few metabolomics assessments based on field accumulated, uncontrolled contaminant exposures in wildlife, particularly in the Arctic. In the present study, targeted metabolomics and contaminant data were analyzed together to assess potential influences of contaminant exposure on the hepatic metabolome of male polar bears (n = 29) from the southern and western Hudson Bay (SHB and WHB respectively), Canada. The 29 metabolites identified as important in the differentiation of the two subpopulations after partial least squares discriminant analysis (PLS-DA) included phosphatidylcholines (PCs), acylcarnitines (ACs; involved in β-oxidation of fatty acids), and the fatty acid (FA) arachidonic acid (ARA). Perfluorinated alkyl substances, polybrominated diphenyl ethers, dichlorodiphenyldichloroethylene (p,p'-DDE) and some highly chlorinated ortho-polychlorinated biphenyl congeners were greater in the SHB bears and were consistently inversely correlated with discriminating ACs and PCs between the subpopulations. The concentrations of discriminatory, legacy organochlorine pesticides along with one tetrachlorobiphenyl were greater in the WHB and were directly correlated with the VIP-identified ACs and PCs. ARA, glycerophospholipid and several amino acid metabolic pathways were identified as different between subpopulations and/or were impacted. ARA is an important, conditionally essential, dietary n-6 FA and is also part of the inflammation response, and elevated concentrations in the SHB could be related to differences in chronic contaminant exposure and/or differences in diet and/or season, among a number of possible explanations. Dietary tracers (stable isotopes of carbon and nitrogen) were correlated with some discriminatory metabolites, supporting the hypothesis that dietary variation was also an important factor in the differentiation of the subpopulations. The results suggest linkages between contaminant exposure in Hudson Bay polar bears and elements of the hepatic metabolome, particularly those related to lipid metabolism.
Collapse
Affiliation(s)
- A D Morris
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, ON, Canada; Department of Chemistry, Carleton University, Ottawa, ON, Canada.
| | - R J Letcher
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, ON, Canada; Department of Chemistry, Carleton University, Ottawa, ON, Canada.
| | - M Dyck
- Department of Environment, Government of Nunavut, Iqaluit, NU, Canada
| | | | | |
Collapse
|
17
|
Lyall K, Croen LA, Weiss LA, Kharrazi M, Traglia M, Delorenze GN, Windham GC. Prenatal Serum Concentrations of Brominated Flame Retardants and Autism Spectrum Disorder and Intellectual Disability in the Early Markers of Autism Study: A Population-Based Case-Control Study in California. ENVIRONMENTAL HEALTH PERSPECTIVES 2017; 125:087023. [PMID: 28895873 PMCID: PMC5783661 DOI: 10.1289/ehp1079] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 05/18/2017] [Accepted: 05/25/2017] [Indexed: 05/21/2023]
Abstract
BACKGROUND Prior studies suggest neurodevelopmental impacts of polybrominated diphenyl ethers (PBDEs), but few have examined diagnosed developmental disorders. OBJECTIVES Our aim was to determine whether prenatal exposure to brominated flame retardants (BFRs) is associated with autism spectrum disorder (ASD) or intellectual disability without autism (ID). METHODS We conducted a population-based case-control study including children with ASD (n=545) and ID (n=181) identified from the California Department of Developmental Services and general population (GP) controls (n=418) from state birth certificates. ASD cases were matched to controls by sex, birth month, and birth year. Concentrations of 10 BFRs were measured in maternal second trimester serum samples stored from routine screening. Logistic regression was used to calculate crude and adjusted odds ratios (AOR) for associations with ASD, and separately for ID, compared with GP controls, by quartiles of analyte concentrations in primary analyses. RESULTS Geometric mean concentrations of five of the six congeners with ≥55% of samples above the limit of detection were lower in mothers of children with ASD or ID than in controls. In adjusted analyses, inverse associations with several congeners were found for ASD relative to GP (e.g., quartile 4 vs. 1, BDE-153: AOR=0.56, 95% CI: 0.38, 0.84). When stratified by child sex (including 99 females with ASD, 77 with ID, and 73 with GP), estimates were consistent with overall analyses in boys, but in the opposite direction among girls, particularly for BDE-28 and -47 (AOR=2.58, 95% CI: 0.86, 7.79 and AOR=2.64, 95% CI: 0.97, 7.19, respectively). Similar patterns overall and by sex were observed for ID. CONCLUSIONS Contrary to expectation, higher PBDE concentrations were associated with decreased odds of ASD and ID, though not in girls. These findings require confirmation but suggest potential sexual dimorphism in associations with prenatal exposure to BFRs. https://doi.org/10.1289/EHP1079.
Collapse
Affiliation(s)
- Kristen Lyall
- A.J. Drexel Autism Institute, Drexel University , Philadelphia, Pennsylvania, USA
| | - Lisa A Croen
- Autism Research Program, Division of Research, Kaiser Permanente , Oakland, California, USA
| | - Lauren A Weiss
- Department of Psychiatry and Institute for Human Genetics, University of California, San Francisco , San Francisco, California, USA
| | - Martin Kharrazi
- Division of Environmental and Occupational Disease Control, California Department of Public Health, Richmond, California, USA
| | - Michela Traglia
- Department of Psychiatry and Institute for Human Genetics, University of California, San Francisco , San Francisco, California, USA
| | - Gerald N Delorenze
- Autism Research Program, Division of Research, Kaiser Permanente , Oakland, California, USA
| | - Gayle C Windham
- Division of Environmental and Occupational Disease Control, California Department of Public Health, Richmond, California, USA
| |
Collapse
|
18
|
Fournier K, Baumont E, Glorennec P, Bonvallot N. Relative toxicity for indoor semi volatile organic compounds based on neuronal death. Toxicol Lett 2017; 279:33-42. [PMID: 28709981 DOI: 10.1016/j.toxlet.2017.07.875] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 07/03/2017] [Accepted: 07/09/2017] [Indexed: 11/30/2022]
Abstract
BACKGROUND Semi Volatile Organic Compounds (SVOCs) are contaminants commonly found in dwellings as a result of their use as plasticizers, flame retardants, or pesticides in building materials and consumer products. Many SVOCs are suspected of being neurotoxic, based on mammal experimentation (impairment of locomotor activity, spatial learning/memory or behavioral changes), raising the question of cumulative risk assessment. The aim of this work is to estimate the relative toxicity of such SVOCs, based on neuronal death. METHOD SVOCs fulfilling the following conditions were included: detection frequency >10% in dwellings, availability of data on effects or mechanism of action for neurotoxicity, and availability of dose-response relationships based on cell viability assays as a proxy of neuronal death. Benchmark concentration values (BMC) were estimated using a Hill model, and compared to assess relative toxicity. RESULTS Of the 58 SVOCs selected, 28 were suspected of being neurotoxic in mammals, and 21 have been documented as inducing a decrease in cell viability in vitro. 13 have at least one dose-response relationship that can be used to derive a BMC based on a 10% fall in neuronal viability. Based on this in vitro endpoint, PCB-153 appeared to be the most toxic compound, having the lowest BMC10 (0.072μM) and diazinon the least toxic compound, having the highest BMC10 (94.35μM). We showed that experimental designs (in particular choice of cell lines) had a significant influence on BMC calculation. CONCLUSION For the first time, the relative in vitro toxicity of 13 indoor contaminants belonging to different chemical families has been assessed on the basis of neuronal cell viability. Lack of comparable toxicity datasets limits the number of SVOCs that can be included. More standardized protocols in terms of cell lines, species and exposure duration should be developed with a view to cumulative risk assessment.
Collapse
Affiliation(s)
- Kevin Fournier
- EHESP School of Public Health, Sorbonne Paris Cité, Avenue du Professeur Léon Bernard, 35043 Rennes Cedex, France; INSERM UMR1085 IRSET (Research Institute in Environmental and Occupational Health), Rennes, France.
| | - Emmanuel Baumont
- EHESP School of Public Health, Sorbonne Paris Cité, Avenue du Professeur Léon Bernard, 35043 Rennes Cedex, France; INSERM UMR1085 IRSET (Research Institute in Environmental and Occupational Health), Rennes, France.
| | - Philippe Glorennec
- EHESP School of Public Health, Sorbonne Paris Cité, Avenue du Professeur Léon Bernard, 35043 Rennes Cedex, France; INSERM UMR1085 IRSET (Research Institute in Environmental and Occupational Health), Rennes, France.
| | - Nathalie Bonvallot
- EHESP School of Public Health, Sorbonne Paris Cité, Avenue du Professeur Léon Bernard, 35043 Rennes Cedex, France; INSERM UMR1085 IRSET (Research Institute in Environmental and Occupational Health), Rennes, France.
| |
Collapse
|
19
|
Abstract
BACKGROUND Recent evidence highlights the reality of unprecedented human exposure to toxic chemical agents found throughout our environment - in our food and water supply, in the air we breathe, in the products we apply to our skin, in the medical and dental materials placed into our bodies, and even within the confines of the womb. With biomonitoring confirming the widespread bioaccumulation of myriad toxicants among population groups, expanding research continues to explore the pathobiological impact of these agents on human metabolism. METHODS This review was prepared by assessing available medical and scientific literature from Medline as well as by reviewing several books, toxicology journals, government publications, and conference proceedings. The format of a traditional integrated review was chosen. RESULTS Toxicant exposure and accrual has been linked to numerous biochemical and pathophysiological mechanisms of harm. Some toxicants effect metabolic disruption via multiple mechanisms. CONCLUSIONS As a primary causative determinant of chronic disease, toxicant exposures induce metabolic disruption in myriad ways, which consequently result in varied clinical manifestations, which are then categorized by health providers into innumerable diagnoses. Chemical disruption of human metabolism has become an etiological determinant of much illness throughout the lifecycle, from neurodevelopmental abnormalities in-utero to dementia in the elderly.
Collapse
Affiliation(s)
- Stephen J Genuis
- a Faculty of Medicine, University of Alberta , Edmonton , Alberta , Canada
| | - Edmond Kyrillos
- b Department of Family Medicine , Faculty of Medicine, University of Ottawa , Ottawa , Ontario , Canada
| |
Collapse
|
20
|
Xu B, Wu M, Pan C, Sun Y, Yuan D, Tang L, Xu G. Aquatic photolysis of hydroxylated polybromodiphenyl ethers under direct UV irradiation: a case study of 2'-HO-BDE-68. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:14409-14416. [PMID: 28432629 DOI: 10.1007/s11356-017-8726-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 02/28/2017] [Indexed: 06/07/2023]
Abstract
Hydroxylated polyhalodiphenyl ethers (HO-PXDEs) have attracted considerable scientific interest as examples of emerging aquatic pollutants. However, a comprehensive assessment of disposal methods for this particular pollutant was seldom investigated. This study examined the UV light degradation of HO-PXDEs, using 2'-HO-2, 3', 4, 5'-tetrabromodiphenyl ether (2'-HO-BDE-68) as a case study. The results showed that UV light was superior to visible light and electron beam irradiation for producing a high degradation rate of 2'-HO-BDE-68. At low concentrations of HO-BDE, the degradation rate was not obviously improved with decreasing initial concentration. The degradation efficiency was also found to be better in alkaline solutions. In a UV/H2O2 system, the hydroxyl radical provided by H2O2 was shown to enhance the degradation efficiency. The main photolysis products of 2'-HO-BDE-68 were identified, and the possible photodegradation pathways were proposed. 1, 3, 8-Tribromodibenzo-p-dioxin was one of the photoproducts, which indicates that secondary pollution must also be considered with the UV photolysis process.
Collapse
Affiliation(s)
- Bentuo Xu
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, People's Republic of China
| | - Minghong Wu
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, People's Republic of China
| | - Chenyuan Pan
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, People's Republic of China
| | - Yan Sun
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, People's Republic of China
| | - Debao Yuan
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, People's Republic of China
| | - Liang Tang
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, People's Republic of China
| | - Gang Xu
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, People's Republic of China.
- Institute of Applied Radiation, School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, People's Republic of China.
| |
Collapse
|
21
|
Nomiyama K, Takaguchi K, Mizukawa H, Nagano Y, Oshihoi T, Nakatsu S, Kunisue T, Tanabe S. Species- and Tissue-Specific Profiles of Polybrominated Diphenyl Ethers and Their Hydroxylated and Methoxylated Derivatives in Cats and Dogs. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:5811-5819. [PMID: 28440655 DOI: 10.1021/acs.est.7b01262] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The adverse effects of elevated polybrominated diphenyl ether (PBDE) levels, reported in the blood of domestic dogs and cats, are considered to be of great concern. However, the tissue distribution of PBDEs and their derivatives in these animals is poorly understood. This study determined the concentrations and profiles of PBDEs, hydroxylated PBDEs (OH-PBDEs), methoxylated PBDEs (MeO-PBDEs), and 2,4,6-tribromophenol (2,4,6-tri-BPh) in the blood, livers, bile, and brains of dogs and cats in Japan. Higher tissue concentrations of PBDEs were found in cats, with the dominant congener being BDE209. BDE207 was also predominant in cat tissues, indicating that BDE207 was formed via BDE209 debromination. BDE47 was the dominant congener in dog bile, implying a species-specific excretory capacity of the liver. OH-PBDE and MeO-PBDE concentrations were several orders of magnitude higher in cat tissues, with the dominant congener being 6OH-BDE47, possibly owing to their intake of naturally occurring MeO-PBDEs in food, MeO-PBDE demethylation in the liver, and lack of UDP-glucuronosyltransferase, UGT1A6. Relatively high concentrations of BDE209, BDE207, 6OH-BDE47, 2'MeO-BDE68, and 2,4,6-tri-BPh were found in cat brains, suggesting a passage through the blood-brain barrier. Thus, cats in Japan might be at a high risk from PBDEs and their derivatives, particularly BDE209 and 6OH-BDE47.
Collapse
Affiliation(s)
- Kei Nomiyama
- Center for Marine Environmental Studies (CMES), Ehime University , Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577, Japan
| | - Kohki Takaguchi
- Center for Marine Environmental Studies (CMES), Ehime University , Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577, Japan
| | - Hazuki Mizukawa
- Graduate School of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo 060-0818, Japan
| | - Yasuko Nagano
- Center for Marine Environmental Studies (CMES), Ehime University , Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577, Japan
| | - Tomoko Oshihoi
- Center for Marine Environmental Studies (CMES), Ehime University , Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577, Japan
| | - Susumu Nakatsu
- Nakatsu Veterinary Surgery, 2-2-5, Shorinjichonishi, Sakai-ku, Sakai, Osaka 590-0960, Japan
| | - Tatsuya Kunisue
- Center for Marine Environmental Studies (CMES), Ehime University , Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577, Japan
| | - Shinsuke Tanabe
- Center for Marine Environmental Studies (CMES), Ehime University , Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577, Japan
| |
Collapse
|
22
|
Human Excretion of Polybrominated Diphenyl Ether Flame Retardants: Blood, Urine, and Sweat Study. BIOMED RESEARCH INTERNATIONAL 2017; 2017:3676089. [PMID: 28373979 PMCID: PMC5360950 DOI: 10.1155/2017/3676089] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 02/26/2017] [Indexed: 01/17/2023]
Abstract
Commonly used as flame retardants, polybrominated diphenyl ethers (PBDEs) are routinely detected in the environment, animals, and humans. Although these persistent organic pollutants are increasingly recognized as having serious health implications, particularly for children, this is the first study, to our knowledge, to investigate an intervention for human elimination of bioaccumulated PBDEs. Objectives. To determine the efficacy of blood, urine, and perspiration as PBDE biomonitoring mediums; assess excretion of five common PBDE congeners (28, 47, 99, 100, and 153) in urine and perspiration; and explore the potential of induced sweating for decreasing bioaccumulated PBDEs. Results. PBDE congeners were not found in urine samples; findings focus on blood and perspiration. 80% of participants tested positive in one or more body fluids for PBDE 28, 100% for PBDE 47, 95% for PBDE 99, and 90% for PBDE 100 and PBDE 153. Induced perspiration facilitated excretion of the five congeners, with different rates of excretion for different congeners. Conclusion. Blood testing provides only a partial understanding of human PBDE bioaccumulation; testing of both blood and perspiration provides a better understanding. This study provides important baseline evidence for regular induced perspiration as a potential means for therapeutic PBDE elimination. Fetotoxic and reproductive effects of PBDE exposure highlight the importance of further detoxification research.
Collapse
|
23
|
Marchitti SA, Mazur CS, Dillingham CM, Rawat S, Sharma A, Zastre J, Kenneke JF. Inhibition of the Human ABC Efflux Transporters P-gp and BCRP by the BDE-47 Hydroxylated Metabolite 6-OH-BDE-47: Considerations for Human Exposure. Toxicol Sci 2016; 155:270-282. [PMID: 28031414 DOI: 10.1093/toxsci/kfw209] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
High body burdens of polybrominated diphenyl ethers (PBDEs) in infants and young children have led to increased concern over their potential impact on human development. PBDE exposure can alter the expression of genes involved in thyroid homeostasis, including those of ATP-binding cassette (ABC) transporters, which mediate cellular xenobiotic efflux. However, little information exists on how PBDEs interact with ABC transporters such as P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP). The purpose of this study was to evaluate the interactions of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) and its hydroxylated metabolite 6-OH-BDE-47 with P-gp and BCRP, using human MDR1- and BCRP-expressing membrane vesicles and stably transfected NIH-3T3-MDR1 and MDCK-BCRP cells. In P-gp membranes, BDE-47 did not affect P-gp activity; however, 6-OH-BDE-47 inhibited P-gp activity at low µM concentrations (IC50 = 11.7 µM). In BCRP membranes, BDE-47 inhibited BCRP activity; however, 6-OH-BDE-47 was a stronger inhibitor [IC50 = 45.9 µM (BDE-47) vs. IC50 = 9.4 µM (6-OH-BDE-47)]. Intracellular concentrations of known P-gp and BCRP substrates [(3H)-paclitaxel and (3H)-prazosin, respectively] were significantly higher (indicating less efflux) in NIH-3T3-MDR1 and MDCK-BCRP cells in the presence of 6-OH-BDE-47, but not BDE-47. Collectively, our results indicate that the BDE-47 metabolite 6-OH-BDE-47 is an inhibitor of both P-gp and BCRP efflux activity. These findings suggest that some effects previously attributed to BDE-47 in biological systems may actually be due to 6-OH-BDE-47. Considerations for human exposure are discussed.
Collapse
Affiliation(s)
- Satori A Marchitti
- U.S. Environmental Protection Agency, National Exposure Research Laboratory, Athens, Georgia 30605
| | - Christopher S Mazur
- U.S. Environmental Protection Agency, National Exposure Research Laboratory, Athens, Georgia 30605
| | - Caleb M Dillingham
- U.S. Environmental Protection Agency, National Exposure Research Laboratory, Athens, Georgia 30605
| | - Swati Rawat
- U.S. Environmental Protection Agency, National Exposure Research Laboratory, Athens, Georgia 30605
| | - Anshika Sharma
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia 30602
| | - Jason Zastre
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia 30602
| | - John F Kenneke
- U.S. Environmental Protection Agency, National Exposure Research Laboratory, Athens, Georgia 30605;
| |
Collapse
|
24
|
Cheikh Rouhou M, Karelis A, St-Pierre D, Lamontagne L. Adverse effects of weight loss: Are persistent organic pollutants a potential culprit? DIABETES & METABOLISM 2016; 42:215-23. [DOI: 10.1016/j.diabet.2016.05.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 05/09/2016] [Accepted: 05/24/2016] [Indexed: 02/05/2023]
|
25
|
Chen Y, Ma S, Li Y, Yan M, Zeng G, Zhang J, Zhang J, Tan X. Microbiological study on bioremediation of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) contaminated soil by agricultural waste composting. Appl Microbiol Biotechnol 2016; 100:9709-9718. [DOI: 10.1007/s00253-016-7798-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Revised: 06/06/2016] [Accepted: 08/08/2016] [Indexed: 11/30/2022]
|
26
|
Chen ZJ, Liu HY, Ho KL, Huang HB, Liu Q, Man YB, Lam MHW, Du J, Wong MH, Wang HS. Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) in paired maternal and neonatal samples from South China: Placental transfer and potential risks. ENVIRONMENTAL RESEARCH 2016; 148:72-78. [PMID: 27035923 DOI: 10.1016/j.envres.2016.03.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 02/02/2016] [Accepted: 03/15/2016] [Indexed: 06/05/2023]
Abstract
Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) are attracting more and more attention for the neurodevelopment toxicity effects. We evaluated the concentrations of 15 individual OH-PBDEs and 3 bromophenol (BRP) congeners in 30 mother-newborn paired placenta, breast milk, fetal cord blood, and neonatal urine samples collected from South China. The geometric mean (GM) concentrations of ∑OH-PBDEs were 37.6, 61.3, and 76.8pgg(-1) ww in placenta, breast milk, and cord blood, respectively. The GM concentrations of ∑BRPs were 47.6, 119, and 30.2pgg(-1) ww in placenta, breast milk, and cord blood, respectively. The GM concentrations of ∑OH-PBDEs and ∑BRPs in neonatal urine were 72.0 and 79.8pgml(-1), respectively. Of the 15 OH-PBDE congeners analyzed, the three most frequently detected congeners were 2'-OH-BDE-68 (72.1%), 6-OH-BDE-47 (67.6%), and 2'-OH-BDE-28 (65.8%). The estimated daily intake (EDI) of OH-PBDEs for the breast-fed infants was 9.31±4.00ngkg(-1) bw day. The accumulation of OH-PBDEs in newborns was much lower than the estimated lowest observed-effect concentration (LOEC) of neurotoxicity. The present study provided the first systematic fundamental data that exposure to OH-PBDEs for newborn and their mothers in South China.
Collapse
Affiliation(s)
- Zhuo-Jia Chen
- Department of Pharmacy, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
| | - Han-Yan Liu
- Center for Reproductive Medicine, Third Affiliated Hospital of Guangzhou Medical University, Key Laboratory for Major Obstetric Diseases of Guangdong Province, Guangzhou 510150, China
| | - Ka-Lok Ho
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, China
| | - Hong-Bin Huang
- Department of Pharmacy, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
| | - Qing Liu
- Department of Pharmacy, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
| | - Yu-Bon Man
- Consortium on Health, Environment, Education and Research (CHEER), and Department of Science and Environmental Studies, Hong Kong Institute of Education, Tai Po, Hong Kong, China; State Key Laboratory in Marine Pollution - Croucher Institute for Environmental Sciences, Hong Kong Baptist University and City University of Hong Kong, Hong Kong, China
| | - Michael Hon-Wah Lam
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, China
| | - Jun Du
- Department of Microbial and Biochemical Pharmacy, School of Pharmaceutical Sciences, Sun Yat-sen University, No. 132 Waihuandong Road, University Town, Guangzhou 510006, China
| | - Ming-Hung Wong
- Consortium on Health, Environment, Education and Research (CHEER), and Department of Science and Environmental Studies, Hong Kong Institute of Education, Tai Po, Hong Kong, China; State Key Laboratory in Marine Pollution - Croucher Institute for Environmental Sciences, Hong Kong Baptist University and City University of Hong Kong, Hong Kong, China.
| | - Hong-Sheng Wang
- Department of Microbial and Biochemical Pharmacy, School of Pharmaceutical Sciences, Sun Yat-sen University, No. 132 Waihuandong Road, University Town, Guangzhou 510006, China.
| |
Collapse
|
27
|
Choi SY, Lee K, Park Y, Lee SH, Jo SH, Chung S, Kim KT. Non-Dioxin-Like Polychlorinated Biphenyls Inhibit G-Protein Coupled Receptor-Mediated Ca2+ Signaling by Blocking Store-Operated Ca2+ Entry. PLoS One 2016; 11:e0150921. [PMID: 26963511 PMCID: PMC4786281 DOI: 10.1371/journal.pone.0150921] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 02/22/2016] [Indexed: 12/12/2022] Open
Abstract
Polychlorinated biphenyls (PCBs) are ubiquitous pollutants which accumulate in the food chain. Recently, several molecular mechanisms by which non-dioxin-like (NDL) PCBs mediate neurodevelopmental and neurobehavioral toxicity have been elucidated. However, although the G-protein coupled receptor (GPCR) is a significant target for neurobehavioral disturbance, our understanding of the effects of PCBs on GPCR signaling remains unclear. In this study, we investigated the effects of NDL-PCBs on GPCR-mediated Ca2+ signaling in PC12 cells. We found that ortho-substituted 2,2’,6-trichlorinated biphenyl (PCB19) caused a rapid decline in the Ca2+ signaling of bradykinin, a typical Gq- and phospholipase Cβ-coupled GPCR, without any effect on its inositol 1,4,5-trisphosphate production. PCB19 reduced thapsigargin-induced sustained cytosolic Ca2+ levels, suggesting that PCB19 inhibits SOCE. The abilities of other NDL-PCBs to inhibit store-operated Ca2+ entry (SOCE) were also examined and found to be of similar potencies to that of PCB19. PCB19 also showed a manner equivalent to that of known SOCE inhibitors. PCB19-mediated SOCE inhibition was confirmed by demonstrating the ability of PCB19 to inhibit the SOCE current and thapsigargin-induced Mn2+ influx. These results imply that one of the molecular mechanism by which NDL-PCBs cause neurobehavioral disturbances involves NDL-PCB-mediated inhibition of SOCE, thereby interfering with GPCR-mediated Ca2+ signaling.
Collapse
Affiliation(s)
- Se-Young Choi
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea
- Department of Life Sciences, Division of Integrative Bioscience and Biotechnology, Pohang University of Science and Technology, Pohang, Korea
| | - Keimin Lee
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea
| | - Yurim Park
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Seung-Hyun Lee
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea
| | - Su-Hyun Jo
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, Korea
| | - Sungkwon Chung
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Kyong-Tai Kim
- Department of Life Sciences, Division of Integrative Bioscience and Biotechnology, Pohang University of Science and Technology, Pohang, Korea
- * E-mail:
| |
Collapse
|
28
|
Hondebrink L, Hermans EJ, Schmeink S, van Kleef RG, Meulenbelt J, Westerink RH. Structure-dependent inhibition of the human α 1 β 2 γ 2 GABA A receptor by piperazine derivatives: A novel mode of action. Neurotoxicology 2015; 51:1-9. [DOI: 10.1016/j.neuro.2015.09.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 09/02/2015] [Accepted: 09/02/2015] [Indexed: 10/23/2022]
|
29
|
Hendriks HS, Westerink RH. Neurotoxicity and risk assessment of brominated and alternative flame retardants. Neurotoxicol Teratol 2015; 52:248-69. [DOI: 10.1016/j.ntt.2015.09.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 09/01/2015] [Accepted: 09/01/2015] [Indexed: 11/29/2022]
|
30
|
Sun Y, Zhang Q, Wang H, Wang W. Quantum chemical investigation on the mechanism and kinetics of OH radical-initiated atmospheric oxidation of PCB-47. CHEMOSPHERE 2015; 133:53-60. [PMID: 25898309 DOI: 10.1016/j.chemosphere.2015.03.040] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 03/08/2015] [Accepted: 03/19/2015] [Indexed: 06/04/2023]
Abstract
The OH radical-initiated atmospheric oxidation degradation of 2,2',4,4'-tetrachlorobiphenyl (PCB-47) was investigated by using quantum chemical calculations. All possible pathways involved in the oxidation process were discussed. Potential barriers and reaction heats have been obtained to assess the energetically favorable reaction pathways and the relatively stable products. The study shows that the OH radicals are more likely to attack the C3 and C5 atom of the aromatic ring in the PCB-47 molecule to form PCB-OH adducts. Subsequent reactions are the addition of O2 or NO2 molecule to the PCB-OH adducts at the ortho position of the OH group. Water molecule plays an important role during the whole degradation process. The individual and overall rate constants were calculated by using the Rice-Ramsperger-Kassel-Marcus (RRKM) theory over the temperature range of 180-370K. At 298K, the atmospheric lifetime of PCB-47 determined by OH radicals is about 9.1d. The computational results are crucial to risk assessment and pollution prevention of PCBs.
Collapse
Affiliation(s)
- Yanhui Sun
- Environment Research Institute, Shandong University, Jinan 250100, PR China
| | - Qingzhu Zhang
- Environment Research Institute, Shandong University, Jinan 250100, PR China.
| | - Hui Wang
- School of Environment, Tsinghua University, Beijing 100084, PR China.
| | - Wenxing Wang
- Environment Research Institute, Shandong University, Jinan 250100, PR China
| |
Collapse
|
31
|
Gross MS, Butryn DM, McGarrigle BP, Aga DS, Olson JR. Primary role of cytochrome P450 2B6 in the oxidative metabolism of 2,2',4,4',6-pentabromodiphenyl ether (BDE-100) to hydroxylated BDEs. Chem Res Toxicol 2015; 28:672-81. [PMID: 25629761 DOI: 10.1021/tx500446c] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human exposure to polybrominated diphenyl ethers (PBDEs) through various routes poses deleterious health effects. PBDEs are biotransformed into hydroxylated metabolites (OH-BDEs) via cytochrome P450s (P450s), which may add to their neurotoxic effects. This study characterizes the in vitro metabolism of 2,2',4,4',6-pentabromodiphenyl ether (BDE-100), one of the most abundant PBDE congeners found in humans, by recombinant human P450s and pooled human liver microsomes (HLMs). Ten recombinant P450s were individually incubated with BDE-100 to monitor P450-specific metabolism. P450 2B6 was found to be the predominant enzyme responsible for nearly all formation of six mono-OH-pentaBDE and two di-OH-pentaBDE metabolites. Four metabolites were identified as 3-hydroxy-2,2',4,4',6-pentabromodiphenyl ether (3-OH-BDE-100), 5'-hydroxy-2,2',4,4',6-pentabromodiphenyl ether (5'-OH-BDE-100), 6'-hydroxy-2,2',4,4',6-pentabromodiphenyl ether (6'-OH-BDE-100), and 4'-hydroxy-2,2',4,5',6-pentabromodiphenyl ether (4'-OH-BDE-103) through use of reference standards. The two remaining mono-OH-pentaBDE metabolites were hypothesized using mass spectral fragmentation characteristics of derivatized OH-BDEs, which allowed prediction of an ortho-OH-pentaBDE and a para-OH-pentaBDE positional isomer. Additional information based on theoretical boiling point calculations using COnductor-like Screening MOdel for Realistic Solvents (COSMO-RS) and experimental chromatographic retention times were used to identify the hypothesized metabolites as 2'-hydroxy-2,3',4,4',6-pentabromodiphenyl ether (2'-OH-BDE-119) and 4-hydroxy-2,2',4',5,6-pentabromodiphenyl ether (4-OH-BDE-91), respectively. Kinetic studies of BDE-100 metabolism using P450 2B6 and HLMs revealed Km values ranging from 4.9 to 7.0 μM and 6-10 μM, respectively, suggesting a high affinity toward the formation of OH-BDEs. Compared to the metabolism of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) and 2,2',4,4',5-pentabromodiphenyl ether (BDE-99) reported in previous studies, BDE-100 appears to be more slowly metabolized by P450s due to the presence of a third ortho-substituted bromine atom.
Collapse
Affiliation(s)
- Michael S Gross
- †Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Deena M Butryn
- †Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Barbara P McGarrigle
- ‡Department of Pharmacology and Toxicology and Department of Epidemiology and Environmental Health, University at Buffalo, The State University of New York, Buffalo, New York 14214, United States
| | - Diana S Aga
- †Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - James R Olson
- ‡Department of Pharmacology and Toxicology and Department of Epidemiology and Environmental Health, University at Buffalo, The State University of New York, Buffalo, New York 14214, United States
| |
Collapse
|
32
|
Genuis SJ, Kelln KL. Toxicant exposure and bioaccumulation: a common and potentially reversible cause of cognitive dysfunction and dementia. Behav Neurol 2015; 2015:620143. [PMID: 25722540 PMCID: PMC4334623 DOI: 10.1155/2015/620143] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 12/31/2014] [Accepted: 12/31/2014] [Indexed: 01/09/2023] Open
Abstract
Juxtaposed alongside the ongoing rise in the incidence and prevalence of dementia, is the surge of recent research confirming widespread exposure and bioaccumulation of chemical toxicants. Evidence from sources such as the Centers for Disease Control reveals that most people have accrued varying degrees of assorted toxic pollutants including heavy metals, flame retardants, and pesticide residues within their bodies. It has been well established that many of these toxicants have neurodegenerative as well as neurodevelopmental impact as a result of various pathophysiologic mechanisms including neuronal mitochondrial toxicity and disruption of neurotransmitter regulation. Elimination of stockpiled toxicants from the body may diminish adverse toxicant impact on human biology and allow restoration of normal physiological function. Incorporating a review of medical literature on toxicant exposure and dementia with a case history of a lead-exposed individual diagnosed with dementia, this paper will discuss a much overlooked and potentially widespread cause of declining brain function and dementia.
Collapse
Affiliation(s)
- Stephen J. Genuis
- Faculty of Medicine at the University of Calgary, Calgary, AB, Canada T2N 4N1
| | - Kasie L. Kelln
- Faculty of Medicine at the University of Saskatchewan, Saskatoon, SK, Canada S7N 5E5
| |
Collapse
|
33
|
Pountney A, Filby AL, Thomas GO, Simpson VR, Chadwick EA, Stevens JR, Tyler CR. High liver content of polybrominated diphenyl ether (PBDE) in otters (Lutra lutra) from England and Wales. CHEMOSPHERE 2015; 118:81-86. [PMID: 25014662 DOI: 10.1016/j.chemosphere.2014.06.051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 06/15/2014] [Indexed: 06/03/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs), used as flame retardants since the 1970s, are being phased out of use, but are persistent and widespread in the environment. Historical declines in Eurasian otter (Lutra lutra) populations have been associated with exposure to dieldrin and polychlorinated biphenyls (PCBs), but links with other persistent organic pollutants have not been explored. In this study, liver samples from 129 otters, collected across England and Wales from 1995-2006, were analysed for PBDEs, together with PCBs, DDT breakdown products, and hexachlorobenzene. Associations with geographical location and life history parameters were explored. Concentrations of PBDEs in otters (∑BDE 12-70000ngg(-1) lipid) paralleled those measured in marine mammals, with PBDE-47 the dominant congener and high levels of PBDE-99 and -100. Otter livers contained high concentrations of PBDE-153 and -209, typical of terrestrial top predators. Inter-individual variation in PBDE concentrations was high and correlated with geographical location. ∑PBDE was 25% of ∑PCB, and comparable with ∑DDT, identifying PBDEs as a major contaminant in otter populations in England and Wales.
Collapse
Affiliation(s)
- Angela Pountney
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Amy L Filby
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Gareth O Thomas
- Lancaster Environment Centre, University of Lancaster, Lancaster, UK(1)
| | - Vic R Simpson
- The Wildlife Veterinary Investigation Centre, Truro, UK
| | - Elizabeth A Chadwick
- Cardiff University Otter Project, School of Biosciences, Cardiff University, Cardiff, UK
| | - Jamie R Stevens
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Charles R Tyler
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK.
| |
Collapse
|
34
|
Costa LG, de Laat R, Tagliaferri S, Pellacani C. A mechanistic view of polybrominated diphenyl ether (PBDE) developmental neurotoxicity. Toxicol Lett 2014; 230:282-94. [PMID: 24270005 PMCID: PMC4028440 DOI: 10.1016/j.toxlet.2013.11.011] [Citation(s) in RCA: 190] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 11/12/2013] [Indexed: 01/01/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs), extensively used in the past few decades as flame retardants in a variety of consumer products, have become world-wide persistent environmental pollutants. Levels in North America are usually higher than those in Europe and Asia, and body burden is 3-to-9-fold higher in infants and toddlers than in adults. The latter has raised concern for potential developmental toxicity and neurotoxicity of PBDEs. Experimental studies in animals and epidemiological observations in humans suggest that PBDEs may be developmental neurotoxicants. Pre- and/or post-natal exposure to PBDEs may cause long-lasting behavioral abnormalities, particularly in the domains of motor activity and cognition. The mechanisms underlying the developmental neurotoxic effects of PBDEs are not known, though several hypotheses have been put forward. One general mode of action relates to the ability of PBDEs to impair thyroid hormone homeostasis, thus indirectly affecting the developing brain. An alternative or additional mode of action involves a direct effect of PBDEs on nervous system cells; PBDEs can cause oxidative stress-related damage (DNA damage, mitochondrial dysfunction, apoptosis), and interfere with signal transduction (particularly calcium signaling), and with neurotransmitter systems. Important issues such as bioavailability and metabolism of PBDEs, extrapolation of results to low level of exposures, and the potential effects of interactions among PBDE congeners and between PBDEs and other contaminants also need to be taken into account.
Collapse
Affiliation(s)
- Lucio G Costa
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA; Department of Neuroscience, University of Parma, Parma, Italy.
| | - Rian de Laat
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | | | | |
Collapse
|
35
|
Ostertag SK, Shaw AC, Basu N, Chan HM. Molecular and neurochemical biomarkers in Arctic beluga whales (Delphinapterus leucas) were correlated to brain mercury and selenium concentrations. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:11551-11559. [PMID: 25171565 DOI: 10.1021/es501369b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Mercury (Hg) concentrations have increased in western Arctic beluga whales (Delphinapterus leucas) since the industrial revolution. Methylmercruy (MeHg) is a known neurotoxicant, yet little is known about the risk of exposure for beluga whales. Selenium (Se) has been linked to demethylation of MeHg in cetaceans, but its role in attenuating Hg toxicity in beluga whales is poorly understood. The objective of this study is to explore relationships between Hg and Se concentrations and neurochemical biomarkers in different brain regions of beluga whales in order to assess potential neurotoxicological risk of Hg exposure in this population. Brain tissue was sampled from hunter-harvested beluga whales from the western Canadian Arctic in 2008 and 2010. Neurochemical and molecular biomarkers were measured with radioligand binding assays and quantitative PCR, respectively. Total Hg (HgT) concentration ranged from 2.6-113 mg kg(-1) dw in temporal cortex. Gamma-amminobutyric acid type A receptor (GABAA-R) binding in the cerebellum was negatively associated with HgT, MeHg and total Se (SeT) concentrations (p ≤ 0.05). The expression of mRNA for GABAA-R subunit α2 was negatively associated with HgT and MeHg (p ≤ 0.05). Furthermore, GABAA-R binding was positively correlated to mRNA expression for GABAA-R α2 subunit, and negatively correlated to the expression of mRNA for GABAA-R α4 subunit (p ≤ 0.05). The expression of N-methyl-d-aspartate receptor (NMDA-R) subunit 2b mRNA expression was negatively associated with iHglabile concentration in the cerebellum (p ≤ 0.05). Variation of molecular and/or biochemical components of the GABAergic and glutamatergic signaling pathways were associated with MeHg exposure in beluga whales. Our results show that MeHg exposure is associated with neurochemical variation in the cerebellum of beluga whales and Se may partially protect from MeHg-associated neurotoxicity.
Collapse
Affiliation(s)
- Sonja K Ostertag
- Natural Resources and Environmental Studies, University of Northern British Columbia , Prince George, British Columbia Canada , V2N 4Z9
| | | | | | | |
Collapse
|
36
|
Chen A, Yolton K, Rauch SA, Webster GM, Hornung R, Sjödin A, Dietrich KN, Lanphear BP. Prenatal polybrominated diphenyl ether exposures and neurodevelopment in U.S. children through 5 years of age: the HOME study. ENVIRONMENTAL HEALTH PERSPECTIVES 2014; 122:856-62. [PMID: 24870060 PMCID: PMC4123029 DOI: 10.1289/ehp.1307562] [Citation(s) in RCA: 151] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 05/21/2014] [Indexed: 05/17/2023]
Abstract
BACKGROUND Polybrominated diphenyl ethers (PBDEs) are persistent chemicals that have been widely used as flame retardants in furniture, carpet padding, car seats, and other consumer products during the past three decades. OBJECTIVE We examined whether in utero exposure to PBDEs is associated with child cognitive function and behavior in a U.S. study sample. METHODS In a prospective birth cohort, we measured maternal serum concentrations of BDE-47 and other PBDE congeners in 309 women at 16 weeks of gestation during 2003-2006 and followed their children in Cincinnati, Ohio. We measured cognitive and motor abilities using the Bayley Scales of Infant Development-II at ages 1, 2, and 3 years; intelligence using the Wechsler Preschool and Primary Scale of Intelligence-III at age 5 years; and children's behaviors using the Behavioral Assessment System for Children-2 annually at ages 2-5 years. We used linear mixed models or generalized estimating equations with adjustment for potential confounders to estimate associations between these outcomes and log10-transformed PBDE concentrations. RESULTS The geometric mean of BDE-47 in maternal serum (20.1 ng/g lipid) was comparable with U.S. adult national reference values. Prenatal BDE-47 was not significantly associated with Bayley Mental or Psychomotor Development Indices at 1-3 years, but a 10-fold increase in prenatal BDE-47 was associated with a 4.5-point decrease (95% CI: -8.8, -0.1) in Full-Scale IQ and a 3.3-point increase (95% CI: 0.3, 6.3) in the hyperactivity score at age 5 years. CONCLUSIONS Prenatal exposure to PBDEs was associated with lower IQ and higher hyperactivity scores in children.
Collapse
Affiliation(s)
- Aimin Chen
- Division of Epidemiology and Biostatistics, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | | | | | | | | | | | | | | |
Collapse
|
37
|
Westerink RHS. Modulation of cell viability, oxidative stress, calcium homeostasis, and voltage- and ligand-gated ion channels as common mechanisms of action of (mixtures of) non-dioxin-like polychlorinated biphenyls and polybrominated diphenyl ethers. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2014; 21:6373-6383. [PMID: 23686757 DOI: 10.1007/s11356-013-1759-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 04/22/2013] [Indexed: 06/02/2023]
Abstract
Non-dioxin-like polychlorinated biphenyls (NDL-PCBs) and polybrominated diphenyl ethers (PBDEs) are environmental pollutants that exert neurodevelopmental and neurobehavioral effects in vivo in humans and animals. Acute in vitro neurotoxic effects include changes in cell viability, oxidative stress, and basal intracellular calcium levels. Though these acute cellular effects could partly explain the observed in vivo effects, other mechanisms, such as effects on calcium influx and neurotransmitter receptor function, likely contribute to the disturbance in neurotransmission. This concise review combines in vitro data on cell viability, oxidative stress and basal calcium levels with recent data that clearly demonstrate that (hydroxylated) PCBs and (hydroxylated) PBDEs can exert acute effects on voltage-gated Ca(2+) channels as well as on excitatory and inhibitory neurotransmitter receptors in vitro. These novel mechanisms of action are shared by NDL-PCBs, OH-PBDEs, and some other persistent organic pollutants, such as tetrabromobisphenol-A, and could have profound effects on neurodevelopment, neurotransmission, and neurobehavior in vivo.
Collapse
Affiliation(s)
- Remco H S Westerink
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, 3508 TD, Utrecht, The Netherlands,
| |
Collapse
|
38
|
Yang D, Kania-Korwel I, Ghogha A, Chen H, Stamou M, Bose DD, Pessah IN, Lehmler HJ, Lein PJ. PCB 136 atropselectively alters morphometric and functional parameters of neuronal connectivity in cultured rat hippocampal neurons via ryanodine receptor-dependent mechanisms. Toxicol Sci 2014; 138:379-92. [PMID: 24385416 DOI: 10.1093/toxsci/kft334] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
We recently demonstrated that polychlorinated biphenyl (PCB) congeners with multiple ortho chlorine substitutions sensitize ryanodine receptors (RyRs), and this activity promotes Ca²⁺-dependent dendritic growth in cultured neurons. Many ortho-substituted congeners display axial chirality, and we previously reported that the chiral congener PCB 136 (2,2',3,3',6,6'-hexachlorobiphenyl) atropselectively sensitizes RyRs. Here, we test the hypothesis that PCB 136 atropisomers differentially alter dendritic growth and other parameters of neuronal connectivity influenced by RyR activity. (-)-PCB 136, which potently sensitizes RyRs, enhances dendritic growth in primary cultures of rat hippocampal neurons, whereas (+)-PCB 136, which lacks RyR activity, has no effect on dendritic growth. The dendrite-promoting activity of (-)-PCB 136 is observed at concentrations ranging from 0.1 to 100 nM and is blocked by pharmacologic RyR antagonism. Neither atropisomer alters axonal growth or cell viability. Quantification of PCB 136 atropisomers in hippocampal cultures indicates that atropselective effects on dendritic growth are not due to differential partitioning of atropisomers into cultured cells. Imaging of hippocampal neurons loaded with Ca²⁺-sensitive dye demonstrates that (-)-PCB 136 but not (+)-PCB 136 increases the frequency of spontaneous Ca²⁺ oscillations. Similarly, (-)-PCB 136 but not (+)-PCB 136 increases the activity of hippocampal neurons plated on microelectrode arrays. These data support the hypothesis that atropselective effects on RyR activity translate into atropselective effects of PCB 136 atropisomers on neuronal connectivity, and suggest that the variable atropisomeric enrichment of chiral PCBs observed in the human population may be a significant determinant of individual susceptibility for adverse neurodevelopmental outcomes following PCB exposure.
Collapse
Affiliation(s)
- Dongren Yang
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California 95616
| | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Alterations to the circuitry of the frontal cortex following exposure to the polybrominated diphenyl ether mixture, DE-71. Toxicology 2013; 312:48-55. [PMID: 23916505 DOI: 10.1016/j.tox.2013.07.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/19/2013] [Accepted: 07/23/2013] [Indexed: 11/21/2022]
Abstract
Recent studies have identified exposure to polybrominated diphenyl ethers (PBDEs) as a risk factor for deficits in cognitive functioning seen in children as well as adults. Additionally, similar alterations in learning and memory have also been observed in animal models of PBDE exposure. However, given these findings, the molecular alterations that may underlie these neurobehavioral endpoints have not been identified. As the frontal cortex is involved in modulating several cognitive functions, the purpose of our study was to investigate the possible changes to the GABAergic and glutamatergic neurotransmitter systems located in the frontal cortex following exposure to the PBDE mixture, DE-71. Primary cultured neurons isolated from the frontal cortex showed a dose-dependent reduction in neurons as well as neurite outgrowth. Furthermore, evaluation of DE-71 neurotoxicity in the frontal cortex using an in vivo model showed alterations to specific proteins involved in mediating GABA and glutamate neurotransmission, including GAD67, vGAT, vGlut, and GABA(A) 2α receptor subunit. Interestingly, these alterations appeared to be preferential for the GABA and glutamate systems located in the frontal cortex. These findings identify specific targets of PBDE neurotoxicity and provide a possible molecular mechanism for PBDE-mediated neurobehavioral deficits that arise from the frontal cortex.
Collapse
|
40
|
Sun J, Liu J, Liu Y, Jiang G. Hydroxylated and methoxylated polybrominated diphenyl ethers in mollusks from Chinese coastal areas. CHEMOSPHERE 2013; 92:322-328. [PMID: 23582706 DOI: 10.1016/j.chemosphere.2013.03.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 02/26/2013] [Accepted: 03/16/2013] [Indexed: 06/02/2023]
Abstract
Hydroxylated polybrominated diphenyl ethers (OH-PBDEs), methoxylated PBDEs (MeO-PBDEs) and PBDEs were determined in three mollusk species collected from three Chinese coastal regions in 2007, 2009, 2010 and 2011. The dominant MeO- and OH-PBDEs isomers detected in mollusks were 6-MeO-BDE-47, 2'-MeO-BDE-68, 6-OH-BDE-47 and 2'-OH-BDE-68. Concentrations of ΣMeO-PBDEs ranged from 9.20 to 2090pgg(-1) dry weight (mean: 450pgg(-1) dry weight). Concentrations of ΣOH-PBDEs ranged from 118 to 2540pgg(-1) dry weight (mean: 534pgg(-1) dry weight). Species differences in accumulation were found for the three mollusk species. Spatial distribution showed that OH- and MeO-PBDEs levels were higher in Weihai than in Tianjin. The temporal trends of OH- and MeO-PBDEs in mollusks were studied during period of 2007 to 2011, rising of ΣOH-PBDEs in Rap from Penglai and Ost from Weihai and declining of ΣMeO-PBDEs in Ost in Penglai were observed. Significant correlations were found between OH- and MeO-PBDEs, but neither between PBDEs and OH-PBDEs, nor between PBDEs and MeO-PBDEs, suggesting that OH- and MeO-PBDEs may have a common source or similar accumulation behavior in mollusks. OH- and MeO-PBDEs were likely not to originate from PBDE precursors.
Collapse
Affiliation(s)
- Jianteng Sun
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China
| | | | | | | |
Collapse
|
41
|
Chen A, Park JS, Linderholm L, Rhee A, Petreas M, DeFranco EA, Dietrich KN, Ho SM. Hydroxylated polybrominated diphenyl ethers in paired maternal and cord sera. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:3902-8. [PMID: 23506475 PMCID: PMC4307929 DOI: 10.1021/es3046839] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) were widely used as flame retardants in the past three decades. These compounds are lipophilic and easily cross the placenta from pregnant woman to fetus. It is not clear whether hydroxylated PBDEs (OH-PBDEs), with greater hydrophilicity, have different concentrations in maternal and cord serum samples. We analyzed PBDEs (BDE-28, -47, -99, -100, -153, -154, -209) and OH-PBDEs (6-OH-BDE-47, 5-OH-BDE-47, 4'-OH-BDE-49, 5'-OH-BDE-99) in 20 pairs of maternal and cord serum samples collected in Cincinnati, OH in 2011. The geometric mean concentration of ∑OH-BDEs (the sum of four OH-PBDEs) was 49.76 pg/mL in cord sera, higher than 32.84 pg/mL in maternal sera. Similarly, cord serum total BDEs had a higher geometric mean than maternal serum (45.51 vs 32.07 ng/g lipid). Equal or higher levels of total OH-BDEs and total BDEs in cord serum were observed in 85% and 80% of the mother-neonate pairs, respectively. The study suggests fetuses might receive higher OH-PBDE and PBDE exposure than their mothers.
Collapse
Affiliation(s)
- Aimin Chen
- Division of Epidemiology and Biostatistics, Department of Environmental Health, Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States
- Address correspondence to Dr. Aimin Chen, Division of Epidemiology and Biostatistics, Department of Environmental Health, University of Cincinnati College of Medicine, P.O. Box 670056, Cincinnati, OH 45267-0056, USA. Tel: 513-558-2129, Fax: 513-558-4397,
| | - June-Soo Park
- Environmental Chemistry Laboratory, California Department of Toxic Substances Control, California Environmental Protection Agency, Berkeley, California, United States
| | - Linda Linderholm
- Environmental Chemistry Laboratory, California Department of Toxic Substances Control, California Environmental Protection Agency, Berkeley, California, United States
| | - Alexandra Rhee
- Environmental Chemistry Laboratory, California Department of Toxic Substances Control, California Environmental Protection Agency, Berkeley, California, United States
| | - Myrto Petreas
- Environmental Chemistry Laboratory, California Department of Toxic Substances Control, California Environmental Protection Agency, Berkeley, California, United States
| | - Emily A. DeFranco
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States
| | - Kim N. Dietrich
- Division of Epidemiology and Biostatistics, Department of Environmental Health, Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States
| | - Shuk-mei Ho
- Division of Epidemiology and Biostatistics, Department of Environmental Health, Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States
| |
Collapse
|
42
|
Li T, Wang W, Pan YW, Xu L, Xia Z. A hydroxylated metabolite of flame-retardant PBDE-47 decreases the survival, proliferation, and neuronal differentiation of primary cultured adult neural stem cells and interferes with signaling of ERK5 MAP kinase and neurotrophin 3. Toxicol Sci 2013; 134:111-24. [PMID: 23564643 DOI: 10.1093/toxsci/kft083] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Polybrominated diphenyl ethers (PBDEs) are a group of organobromine compounds widely used as flame retardants. PBDE-47 is one of the most prominent PBDE congeners found in human tissues, and it can be transformed into several metabolites, including 6-OH-PBDE-47. Recent studies have shown that PBDE-47 is neurotoxic to animals and possibly humans. However, the basis for the neurotoxicity of PBDEs and their metabolites is unclear. For example, it is not known whether PBDEs affect adult neurogenesis, a process implicated in learning and memory and in olfactory behavior. In this study, we examined the toxicity of PBDEs for primary adult neural stem/progenitor cells (aNSCs) isolated from the subventricular zone (SVZ) of adult mice. We discovered that 6-OH-PBDE-47, but not its parent compound PBDE-47, is cytotoxic for aNCSs using MTS metabolism and cell number as a measure of cytotoxicity. Interestingly, 6-OH-PBDE-47 induced apoptosis at concentrations above 7.5μM inhibited proliferation at 2.5-5μM while suppressing neuronal and oligodendrocyte differentiation at submicromolar concentrations (≤ 1μM). The effect on proliferation was reversed upon removal of 6-OH-PBDE-47 and correlated with selective but reversible inhibition of ERK5 activation by mitogenic growth factors EGF and bFGF. 6-OH-PBDE-47 also inhibited the proneuronal differentiation effect of neurotrophin 3 (NT3) and NT3 activation of ERK5. Together, these data show that 6-OH-PBDE-47 is more toxic than its parent compound for SVZ-derived aNSCs and that it inhibits multiple aspects of adult neurogenesis. Furthermore, inhibition of ERK5 signaling may underlie the adverse effect of 6-OH-PBDE-47 on proliferation and neuronal differentiation. Our data suggest that exposure to PBDE-based flame retardants could cause neurotoxicity in the adult brain by interfering with adult neurogenesis.
Collapse
Affiliation(s)
- Tan Li
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | | | | | | | | |
Collapse
|
43
|
Feo ML, Gross MS, McGarrigle BP, Eljarrat E, Barceló D, Aga DS, Olson JR. Biotransformation of BDE-47 to potentially toxic metabolites is predominantly mediated by human CYP2B6. ENVIRONMENTAL HEALTH PERSPECTIVES 2013; 121:440-6. [PMID: 23249762 PMCID: PMC3620761 DOI: 10.1289/ehp.1205446] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 12/17/2012] [Indexed: 05/03/2023]
Abstract
BACKGROUND Previous studies have indicated that cytochrome P450s (CYPs) are involved in the metabolism of polybrominated diphenyl ether (PBDE) flame retardants in humans, resulting in the formation of hydroxylated PBDEs (OH-PBDEs) that are potentially more toxic than the parent PBDEs. However, the specific enzymes responsible for the formation of OH-PBDEs are unknown. OBJECTIVES The purposes of this study were to characterize the in vitro metabolism of 2,2´,4,4´-tetrabromodiphenyl ether (BDE-47) by human liver microsomes (HLM) and recombinant human CYPs, and to identify the CYP(s) that are active in the oxidative metabolism of BDE-47. METHODS Recombinant human CYPs (CYP1A1, 1A2, 1B1, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, and 3A4) were incubated with BDE-47 (20 µM), and the metabolites were measured and characterized using gas chromatography with tandem mass spectrometry (GC-MS/MS). For kinetic studies, CYP2B6 and pooled human liver microsomes (HLMs) were incubated with BDE-47 (0-60 µM). RESULTS CYP2B6 was the predominant CYP capable of forming six OH-BDEs, including 3-OH-BDE-47, 5-OH-BDE-47, 6-OH-BDE-47, 4-OH-BDE-42, 4´-OH-BDE-49, and a metabolite tentatively identified as 2´-OH-BDE-66. On the basis of full-scan GC-MS analysis, we hypothesized the formation of two other metabolites: di-OH-tetra-BDE and di-OH-tetrabrominated dioxin. In kinetic studies of BDE-47 metabolism by CYP2B6 and pooled HLMs, we found Km values ranging from 3.8 to 6.4 µM and 7.0 to 11.4 µM, respectively, indicating the high affinity toward the formation of OH-BDEs. CONCLUSION Our findings support a predominant role of CYP2B6 in the metabolism of BDE-47 to potentially toxic metabolites, including a hypothesized di-OH-tetrabrominated dioxin metabolite. These results will assist future epidemiological studies investigating the potential of PBDEs and their metabolites to produce neurobehavioral/neurodevelopmental disorders.
Collapse
Affiliation(s)
- Maria Luisa Feo
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
| | | | | | | | | | | | | |
Collapse
|
44
|
Hondebrink L, Tan S, Hermans E, van Kleef RG, Meulenbelt J, Westerink RH. Additive inhibition of human α1β2γ2 GABAA receptors by mixtures of commonly used drugs of abuse. Neurotoxicology 2013; 35:23-9. [DOI: 10.1016/j.neuro.2012.12.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 11/23/2012] [Accepted: 12/11/2012] [Indexed: 10/27/2022]
|
45
|
Slotkin TA, Card J, Infante A, Seidler FJ. BDE99 (2,2',4,4',5-pentabromodiphenyl ether) suppresses differentiation into neurotransmitter phenotypes in PC12 cells. Neurotoxicol Teratol 2013; 37:13-7. [PMID: 23422510 DOI: 10.1016/j.ntt.2013.02.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 01/23/2013] [Accepted: 02/02/2013] [Indexed: 11/29/2022]
Abstract
Early-life exposures to brominated diphenyl ethers (BDEs) lead to neurobehavioral abnormalities later in life. Although these agents are thyroid disruptors, it is not clear whether this mechanism alone accounts for the adverse effects. We evaluated the impact of 2,2',4,4',5-pentabromodiphenyl ether (BDE99) on PC12 cells undergoing neurodifferentiation, contrasting the effects with chlorpyrifos, a known developmental neurotoxicant. BDE99 elicited decrements in the number of cells, evidenced by a reduction in DNA levels, to a lesser extent than did chlorpyrifos. This did not reflect cytotoxicity from oxidative stress, since cell enlargement, monitored by the total protein/DNA ratio, was not only unimpaired by BDE99, but was actually enhanced. Importantly, BDE99 impaired neurodifferentiation into both the dopamine and acetylcholine neurotransmitter phenotypes. The cholinergic phenotype was affected to a greater extent, so that neurotransmitter fate was diverted away from acetylcholine and toward dopamine. Chlorpyrifos produced the same imbalance, but through a different underlying mechanism, promoting dopaminergic development at the expense of cholinergic development. In our earlier work, we did not find these effects with BDE47, a BDE that has greater endocrine disrupting and cytotoxic effects than BDE99. Thus, our results point to interference with neurodifferentiation by specific BDE congeners, distinct from cytotoxic or endocrine mechanisms.
Collapse
Affiliation(s)
- Theodore A Slotkin
- Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, NC, 27710, USA.
| | | | | | | |
Collapse
|
46
|
de Cock M, Maas YGH, van de Bor M. Does perinatal exposure to endocrine disruptors induce autism spectrum and attention deficit hyperactivity disorders? Review. Acta Paediatr 2012; 101:811-8. [PMID: 22458970 DOI: 10.1111/j.1651-2227.2012.02693.x] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
AIM To provide an overview of studies on perinatal exposure in humans to endocrine disrupting chemicals (EDCs) in relation to autism spectrum (ASD) and attention deficit hyperactivity (ADHD) disorders. METHODS A review of the literature (PubMed) was performed. Exposure-related keywords, including various chemicals, were matched with keywords describing outcome. Animal studies as well as publications not written in English were excluded. In total, 834 titles were retrieved. The final selection included 21 publications. RESULTS Positive associations were found for ASD in relation to exposure to all chemicals investigated, which included hazardous air pollutants, pesticides and bisphenol A (BPA). Increased risks of ADHD or positive associations were found for exposure to polychlorinated biphenyls (PCBs), dialkyl phosphate (DAP) and chlorpyrifos. BPA, polybrominated diphenylethers (PBDEs) and low molecular weight (LMW) phthalates were positively associated with externalizing behaviour. Five of 17 studies did not find any association between exposure and ADHD. CONCLUSION Perinatal exposure to EDCs appears to be associated with the occurrence of ASD as well as ADHD. Disruption of thyroid hormone function and gamma-aminobutyric acid (GABA)ergic mechanisms may offer an explanation for the observed relations; though, conclusive evidence in humans is limited.
Collapse
Affiliation(s)
- Marijke de Cock
- Department of Health and Life Sciences, VU University, Amsterdam, The Netherlands
| | | | | |
Collapse
|
47
|
Hendriks HS, van Kleef RGDM, Westerink RHS. Modulation of human α4β2 nicotinic acetylcholine receptors by brominated and halogen-free flame retardants as a measure for in vitro neurotoxicity. Toxicol Lett 2012; 213:266-74. [PMID: 22750351 DOI: 10.1016/j.toxlet.2012.06.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 06/18/2012] [Accepted: 06/20/2012] [Indexed: 11/16/2022]
Abstract
Brominated flame retardants (BFRs) are abundant persistent organic pollutants with well-studied toxicity. The toxicological and ecological concern associated with BFRs argues for replacement by safer alternatives. However, the (neuro)toxic potential of alternative halogen-free flame retardants (HFFRs) is unknown. Previous research identified the nervous system as a sensitive target organ for BFRs, with modulation of excitatory nicotinic acetylcholine (nACh) receptors as one of the modes of action. Since it is essential to assess the (neuro)toxic potential of HFFRs before large scale use, we measured the effects of three BFRs and 13 HFFRs on the function of human α(4)β(2) nACh receptors, expressed in Xenopus oocytes, using the two-electrode voltage-clamp technique. The results demonstrate that some BFRs (TBBPA and to a lesser extent BDE-209) and HFFRs (TPP, Alpi, APP, MMT and to a lesser extent ATH, ATO, MHO, MPP, RDP and ZHS) act as nACh receptor antagonists. Contrary, BPS, BDP, DOPO and ZS were unable to modulate nACh receptors. Despite the lack of toxicological data on HFFRs and the need for additional studies to perform a full (neuro)toxic risk assessment, the current data on antagonistic effects on nACh receptors could be an important step in prioritizing viable HFFRs for substitution of BFRs.
Collapse
Affiliation(s)
- Hester S Hendriks
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht, The Netherlands
| | | | | |
Collapse
|
48
|
Hendriks HS, van Kleef RGDM, van den Berg M, Westerink RHS. Multiple novel modes of action involved in the in vitro neurotoxic effects of tetrabromobisphenol-A. Toxicol Sci 2012; 128:235-46. [PMID: 22547355 DOI: 10.1093/toxsci/kfs136] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Neurotoxicological data on the widely used brominated flame retardant tetrabromobisphenol-A (TBBPA) is limited. Since recent studies indicated that inhibitory GABA(A) and excitatory α(4)β(2) nicotinic acetylcholine (nACh) receptors are sensitive targets for persistent organic pollutants, we investigated the effects of TBBPA on these receptors, expressed in Xenopus oocytes, using the two-electrode voltage-clamp technique. Our results demonstrate that TBBPA acts as full (≥ 10 μM) and partial (≥ 0.1 μM) agonist on human GABA(A) receptors, whereas it acts as antagonist (≥ 10 μM) on human α(4)β(2) nACh receptors. Next, neuronal B35 cells were used to further study the effects of TBBPA on calcium-permeable nACh receptors using single-cell fluorescent calcium imaging. These results demonstrate that TBBPA (≥ 1 μM) inhibits acetylcholine (ACh) receptors as evidenced by a reduction in the ACh-evoked increases in the intracellular calcium concentration ([Ca(2+)](i)). Additionally, TBBPA (> 1 μM) induced a strong and concentration-dependent increase in basal [Ca(2+)](i) in B35 cells. Similarly, TBBPA (> 1 μM) increases basal [Ca(2+)](i) in dopaminergic PC12 cells. This increase is also evident under calcium-free conditions, indicating it originates from intracellular calcium stores. Moreover, depolarization-evoked increases in [Ca(2+)](i) are strongly reduced by TBBPA (≥ 1 μM), indicating TBBPA-induced inhibition of voltage-gated calcium channels. Our in vitro studies thus demonstrate that TBBPA exerts several adverse effects on functional neurotransmission endpoints with effect concentrations that are only two orders of magnitude below the highest cord serum concentrations. Although epidemiological proof for adverse TBBPA effects is lacking, our data justify the quest for flame retardants with reduced neurotoxic potential.
Collapse
Affiliation(s)
- Hester S Hendriks
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Utrecht University, NL-3508 TD Utrecht, The Netherlands
| | | | | | | |
Collapse
|
49
|
Heredia L, Torrente M, Colomina MT, Domingo JL. Behavioral effects of oral subacute exposure to BDE-209 in young adult mice: A preliminary study. Food Chem Toxicol 2012; 50:707-12. [DOI: 10.1016/j.fct.2011.12.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 11/30/2011] [Accepted: 12/01/2011] [Indexed: 10/14/2022]
|
50
|
Langeveld WT, Meijer M, Westerink RHS. Differential effects of 20 non-dioxin-like PCBs on basal and depolarization-evoked intracellular calcium levels in PC12 cells. Toxicol Sci 2012; 126:487-96. [PMID: 22218490 DOI: 10.1093/toxsci/kfr346] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Non-dioxin-like polychlorinated biphenyls (NDL-PCBs) are environmental pollutants that are well known for their neurotoxic effects. Numerous in vitro studies reported PCB-induced increases in the basal intracellular calcium concentration ([Ca(2+)](i)), and in vivo NDL-PCB neurotoxicity appears at least partly mediated by these disturbances. However, effects of NDL-PCBs on depolarization-evoked calcium influx are poorly investigated, and effects of several congeners, including PCB53, on calcium homeostasis are still unknown. We therefore studied the effects of 20 selected NDL-PCBs on basal and depolarization-evoked [Ca(2+)](i) in fura-2-loaded PC12 cells using single-cell fluorescence microscopy. The results demonstrate that hexa- and heptachlorobiphenyls (with the exception of PCB136) were unable to affect basal and depolarization-evoked [Ca(2+)](i). However, most tri- and tetrachlorinated as well as some pentachlorinated NDL-PCBs (at 1 and 10μM) increased basal [Ca(2+)](i) during a 15-min exposure. The increase in basal [Ca(2+)](i), which differed in kinetics for the different congeners, depended partly on influx of extracellular calcium and calcium release from the endoplasmic reticulum. Importantly, all tested tri- and tetrachlorinated biphenyls and some pentachlorinated NDL-PCBs (PCB95, PCB100, and PCB104) reduced depolarization-evoked [Ca(2+)](i), with PCB51 and PCB53 being most potent (near complete inhibition at 1μM). The reduction in depolarization-evoked calcium influx depended on the exposure duration but not on the foregoing PCB-induced increase in basal [Ca(2+)](i). The inhibition of voltage-gated calcium channels is a novel and sensitive mode of action for NDL-PCBs that contributes to the disturbances in calcium homeostasis and likely is related to NDL-PCB-induced (developmental) neurotoxicity.
Collapse
Affiliation(s)
- Wendy T Langeveld
- Neurotoxicology Research Group, Institute for Risk Assessment Sciences, Utrecht University, NL-3508 TD Utrecht, The Netherlands
| | | | | |
Collapse
|