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De Angelis M, Schramm KW. Perinatal effects of persistent organic pollutants on thyroid hormone concentration in placenta and breastmilk. Mol Aspects Med 2021;:100988. [PMID: 34238594 DOI: 10.1016/j.mam.2021.100988] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/30/2021] [Accepted: 06/08/2021] [Indexed: 12/18/2022]
Abstract
Thyroid hormones (TH) are known to play a critical role in regulating many biological processes including growth and development, energy homeostasis, thermogenesis, lipolysis and metabolism of cholesterol. Severe TH deficiency especially during fetal development results in cretinism, but can also lead to an imbalance in metabolism with, among others, an alteration in body weight composition. Over the past two decades, increasing evidence has shown that certain persistent organic pollutants (POP) can interfere with the endocrine system. These POP referred to as "endocrine disrupting chemicals" are widely present in the environment and populations are exposed globally. Moreover, epidemiological studies have shown that a particularly sensitive period is the pre- and postnatal time. Indeed, perinatal exposure to such chemicals could lead to the onset diseases in later life. It is known, that, maternal thyroid hormones are transported by the placenta to the fetus from 6 weeks of gestation and it seems that during the first trimester, and part of the second, the fetus is entirely dependent on maternal TH supply for its development. Interferences in the TH-network as a consequence of the exposure to such pollutants could cause variations in TH concentration. Only small changes in maternal thyroid hormone levels in early stages of pregnancy can influence fetal neurological and cardiovascular development, as well as according to recent studies, have effect on childhood body composition. With this review, we will report the most recent and important studies concerning the association between thyroid hormone concentration and POP levels measured during the perinatal period. We will mostly focus on the data recently reported on placenta and breastmilk as main sources for understanding the potential consequences of exposure. The possible link between exposure to pollutants, TH dysregulation and possible adverse outcome will also be briefly discussed. From our literature search, several studies support the hypothesis that pre- and postnatal exposure to different pollutants might play a role in causing variation in thyroid hormone concentration. However, few research papers have so far studied the relationship linking exposure to pollutants, TH concentration and possible health consequences. Therefore, this review highlights the need for further research in this direction.
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Warner M, Rauch S, Ames J, Mocarelli P, Brambilla P, Signorini S, Eskenazi B. Prenatal dioxin exposure and thyroid hormone levels in the Seveso second generation study. Environ Res 2020; 183:109280. [PMID: 32311913 PMCID: PMC7176740 DOI: 10.1016/j.envres.2020.109280] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/14/2020] [Accepted: 02/19/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND In animal studies, perinatal exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) alters thyroid homoeostasis and thyroid hormone concentrations; epidemiologic evidence is limited. OBJECTIVES We aimed to determine the association of prenatal exposure to TCDD with thyroid hormone concentrations in the Seveso Second Generation Study, a unique cohort of children born to TCDD-exposed women resulting from a 1976 chemical factory explosion in Seveso, Italy. METHODS We included 570 children (288 female, 282 male) with complete follow-up data, including a fasting blood draw. Serum levels of total and free thyroxine (T4), free triiodothyronine (T3), and thyroid stimulating hormone (TSH) were measured using immunoassays. We defined prenatal TCDD exposure as: 1) maternal initial TCDD concentration measured in serum collected soon after the explosion and 2) maternal TCDD estimated at pregnancy. RESULTS Compared to the lowest quartile (Q1), maternal initial serum TCDD was associated with lower free T3 (Q2: adj-β = -0.13, 95%CI -0.26, 0.00; Q3: adj-β = -0.22, 95%CI -0.35, -0.09; Q4: adj-β = -0.14, 95%CI -0.28, 0.00; p-trend = 0.02). In participants with high thyroid antibody status, inverse associations between maternal initial serum TCDD and free T3 were significantly stronger than in participants with normal antibody status (p-interaction = 0.02). We also observed a positive association between maternal initial serum TCDD and TSH concentrations in participants with high thyroid antibody status (Q2: adj-β = 11.4%, 95%CI -25.2, 66.1; Q3: adj-β = 49.0%, 95%CI 3.0, 115.5; Q4: adj-β = 105.5, 95%CI 36.6, 209.2; p-trend < 0.01) but not in those participants with normal antibody status (p-interaction < 0.01). Similar results were found for TCDD estimated at pregnancy. DISCUSSION Our results suggest prenatal exposure to TCDD, a potent endocrine-disrupting compound, may alter thyroid function later in life. Populations with additional thyroid stress may be particularly susceptible to in utero exposure of thyroid disrupting chemicals.
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Affiliation(s)
- Marcella Warner
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California at Berkeley, Berkeley, CA, USA.
| | - Stephen Rauch
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California at Berkeley, Berkeley, CA, USA
| | - Jennifer Ames
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California at Berkeley, Berkeley, CA, USA
| | - Paolo Mocarelli
- Department of Laboratory Medicine, University of Milano-Bicocca, School of Medicine, Hospital of Desio, Desio, Milano, Italy
| | - Paolo Brambilla
- Department of Laboratory Medicine, University of Milano-Bicocca, School of Medicine, Hospital of Desio, Desio, Milano, Italy
| | - Stefano Signorini
- Department of Laboratory Medicine, University of Milano-Bicocca, School of Medicine, Hospital of Desio, Desio, Milano, Italy
| | - Brenda Eskenazi
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California at Berkeley, Berkeley, CA, USA
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Magliocco G, Rodieux F, Desmeules J, Samer CF, Daali Y. Toward precision medicine in pediatric population using cytochrome P450 phenotyping approaches and physiologically based pharmacokinetic modeling. Pediatr Res 2020; 87:441-9. [PMID: 31600772 DOI: 10.1038/s41390-019-0609-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 09/04/2019] [Accepted: 09/22/2019] [Indexed: 01/18/2023]
Abstract
The activity of drug-metabolizing enzymes (DME) shows high inter- and intra-individual variability. Genetic polymorphisms, exposure to drugs, and environmental toxins are known to significantly alter DME expression. In addition, the activity of these enzymes is highly age-dependent due to maturation processes that occur during development. Currently, there is a vast choice of phenotyping methods in adults using exogenous probes to characterize the activity of these enzymes. However, this can hardly be applied to children since it requires the intake of non-therapeutic xenobiotics. In addition, sampling may be challenging in the pediatric population for a variety of reasons: limited volume (e.g., blood), inappropriate sampling methods for age (e.g., urine), and metric requiring invasive or multiple blood samples. This review covers the main existing methods that can be used in the pediatric population to determine DME activity, with a particular focus on cytochrome P450 enzymes. Less invasive tools are described, including phenotyping using endogenous probes. Finally, the potential of pediatric model-informed precision dosing using physiologically based pharmacokinetic modeling is discussed.
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LaKind JS, Lehmann GM, Davis MH, Hines EP, Marchitti SA, Alcala C, Lorber M. Infant Dietary Exposures to Environmental Chemicals and Infant/Child Health: A Critical Assessment of the Literature. Environ Health Perspect 2018; 126:96002. [PMID: 30256157 PMCID: PMC6375563 DOI: 10.1289/ehp1954] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 08/02/2018] [Accepted: 08/13/2018] [Indexed: 05/24/2023]
Abstract
BACKGROUND The benefits of breastfeeding to the infant and mother have been well documented. It is also well known that breast milk contains environmental chemicals, and numerous epidemiological studies have explored relationships between background levels of chemicals in breast milk and health outcomes in infants and children. OBJECTIVES In this paper, we examine epidemiological literature to address the following question: Are infant exposures to background levels of environmental chemicals in breast milk and formula associated with adverse health effects? We critically review this literature a) to explore whether exposure-outcome associations are observed across studies, and b) to assess the literature quality. METHODS We reviewed literature identified from electronic literature searches. We explored whether exposure-outcome associations are observed across studies by assessing the quality (using a modified version of a previously published quality assessment tool), consistency, and strengths and weaknesses in the literature. The epidemiological literature included cohorts from several countries and examined infants/children either once or multiple times over weeks to years. Health outcomes included four broad categories: growth and maturation, morbidity, biomarkers, and neurodevelopment. RESULTS The available literature does not provide conclusive evidence of consistent or clinically relevant health consequences to infants exposed to environmental chemicals in breast milk at background levels. CONCLUSIONS It is clear that more research would better inform our understanding of the potential for health impacts from infant dietary exposures to environmental chemicals. A critical data gap is a lack of research on environmental chemicals in formula and infant/child health outcomes. https://doi.org/10.1289/EHP1954.
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Affiliation(s)
- Judy S LaKind
- 1 LaKind Associates, LLC, Catonsville, Maryland, USA
- 2 Department of Epidemiology and Public Health, University of Maryland School of Medicine , Baltimore, Maryland, USA
| | - Geniece M Lehmann
- 3 Office of Research and Development (ORD), U.S. Environmental Protection Agency (EPA), Research Triangle Park , North Carolina, USA
| | - Matthew H Davis
- 4 Office of Children's Health Protection, U.S. EPA, Washington, District of Columbia, USA
| | - Erin P Hines
- 3 Office of Research and Development (ORD), U.S. Environmental Protection Agency (EPA), Research Triangle Park , North Carolina, USA
| | - Satori A Marchitti
- 5 Oak Ridge Institute for Science and Education (ORISE), ORD, U.S. EPA, Athens, Georgia, USA
| | - Cecilia Alcala
- 6 Association of Schools and Programs of Public Health (ASPPH), ORD, U.S. EPA, Washington, District of Columbia, USA
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Abstract
Objetivos:Estimar a magnitude da associação entre a exposição a resíduos de pesticidas organoclorados (OC) e alterações de marcadores hepáticos.Método: Estudo seccional conduzido em população exposta a OC residente em Cidade dos Meninos,Duque de Caxias (RJ), Brasil (n=354). Foram calculadas as taxas de alterações dos marcadores hepáticos (Alanina aminotransferase (ALT), Aspartato aminotransferase (AST), fosfatase alcalina, gama glutamil transpeptidase (GGT) e albumina) e, em seguida, por meio de regressão logística binária não condicional, foi estimada a associação entre a presença ou não de alterações e os grupos de exposição, criados com base na exposição a alimentos, solo e água contaminados no local. Razões de chance (Odds ratio- OR) brutas e ajustadas para os grupos de exposição e para os fatores de confusão e seus respectivos intervalos de confiança (IC95%) foram obtidos.Resultados:Após ajuste pela regressão logística, os resultados do presente estudo apontam para nenhuma associação entre alterações em enzimas hepáticas e a exposição a OC.Conclusão:O achado sugere que o metabolismo que envolve a distribuição e a biotransformação de OC no organismo não envolve toxicidade direta ao fígado.
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Goodman JE, Kerper LE, Boyce CP, Prueitt RL, Rhomberg LR. Weight-of-evidence analysis of human exposures to dioxins and dioxin-like compounds and associations with thyroid hormone levels during early development. Regul Toxicol Pharmacol 2010; 58:79-99. [PMID: 20416351 DOI: 10.1016/j.yrtph.2010.04.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 03/19/2010] [Accepted: 04/15/2010] [Indexed: 11/29/2022]
Abstract
Thyroid hormones play a critical role in the proper development of brain function and cell growth. Several epidemiological studies have been conducted to assess potential associations between pre- and post-natal exposure to dioxins or dioxin-like compounds (DLCs) and the levels of circulating thyroid hormones during early development. Dioxins and DLCs include chlorinated dibenzo-p-dioxins, chlorinated dibenzofurans, and mono- and non-ortho polychlorinated biphenyls (PCBs). We identified a total of 23 relevant epidemiological studies (21 cohort studies and 1 case-control study) that measured exposures to various types of dioxins and DLCs as well as markers of thyroid function, such as thyroid stimulating hormone (TSH), total thyroxine (T4), free T4, total triiodothyroxine (T3), free T3, and thyroid-binding globulin concentrations in cord blood or circulation. While some of the studies reported associations between concentrations of dioxins and/or DLCs and some biomarkers of thyroid function, the majority of the observed associations were not statistically significant. Moreover, there were no clear and consistent effects across studies for any of the hormone levels examined, and while a number of studies showed a statistically significant association with exposure for a given marker of thyroid function, other studies showed either no change or changes in the opposite direction for the same thyroid function marker. Similarly, when the results were analyzed considering developmental stage, there generally were no clear and consistent effects at any age from birth through 12 years of age. The absence of a clear correlation between background exposures to dioxins and DLCs and thyroid function biomarkers during development is not consistent with the hypothesis that background exposures to these chemicals cause effects on thyroid function during development.
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Kovacic P, Edwards C. Integrated approach to the mechanisms of thyroid toxins: electron transfer, reactive oxygen species, oxidative stress, cell signaling, receptors, and antioxidants. J Recept Signal Transduct Res 2010; 30:133-42. [DOI: 10.3109/10799891003702678] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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LaKind JS, Berlin CM, Mattison DR. The heart of the matter on breastmilk and environmental chemicals: essential points for healthcare providers and new parents. Breastfeed Med 2008; 3:251-9. [PMID: 19086828 DOI: 10.1089/bfm.2008.0121] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract The increasing number of environmental chemicals measured in breastmilk is a consequence of improved analytical capabilities and the increased interest in biomonitoring. It has been generally concluded that the benefits to the infant from breastfeeding outweigh potential risks associated with environmental chemical exposures associated with breastfeeding. However, there have been reports of subtle effects on infants associated with chemicals in breastmilk. Associations between concentrations of chemicals in breastmilk and a biochemical or other change in infants may signal the need for further study or regulatory action, whereas on an individual level, these changes may not be considered adverse. For healthcare providers, this distinction is critical, as many in the field are being asked for nuanced information on risks and benefits associated with breastfeeding, and this information is not readily available. Recognizing the challenge faced by healthcare providers, we have explored and developed a case study on dioxins in breastmilk. The essential conclusion for healthcare providers and new parents is that in studies of breastfed versus formula-fed infants across time, including times when levels of environmental chemicals such as dioxins were higher, beneficial effects associated with breastfeeding have been found. The current evidence does not support altering the World Health Organization recommendations promoting and supporting breastfeeding.
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Zheng GJ, Leung AOW, Jiao LP, Wong MH. Polychlorinated dibenzo-p-dioxins and dibenzofurans pollution in China: sources, environmental levels and potential human health impacts. Environ Int 2008; 34:1050-1061. [PMID: 18440070 DOI: 10.1016/j.envint.2008.02.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Revised: 01/31/2008] [Accepted: 02/20/2008] [Indexed: 05/26/2023]
Abstract
This review represents an assessment of the pollution status of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in China (the mainland, Hong Kong and Taiwan). During the past decades, seven PCDD/Fs pollution hotspots have been found: (a). Ya-er Lake, Hubei Province, with 'total PCDD/Fs' level reaching 177,427 pg g(-1) (dry weight) in lake sediments; (b). Chinese Schistosomiasis affected areas of Jiangxi Province with 33,660 pg g(-1) in soil; (c). e-waste recycling area of Yangtze River Delta, with 2726 pg g(-1) in paddy soil; (d). e-waste recycling area of Guiyu (eastern part of Guangdong Province), with 967,500 pg g(-1) in mixture of burnt residue and soil (the highest level among all hotspots); (e). Pearl River Delta with 2630 pg g(-1) in coastal sediment. (f). Kwun Tong, Victoria Harbour, Hong Kong with 10,999 pg g(-1) in coastal sediment; and (g). southern Taiwan with 606,000 pg g(-1) in soil near the vicinity of a pentachlorophenol manufacturing factory. The main sources of PCDD/Fs in China were formed from impurities during the production of polychlorophenol, hexachlorobenzene, polychlorinated biphenyls, organic chlorinated pesticide and triclosan. In addition, sources of PCDD/Fs included municipal waste incineration, mineral fuel usage, open burning of electronic waste and crop residues, industrial waste discharge and vehicle exhaust emission. Due to potential human health risks from long-term exposure to PCDD/Fs at these hotspots, body loadings of these contaminants should be monitored.
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Affiliation(s)
- Gene J Zheng
- Croucher Institute for Environmental Sciences, and Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China
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Simon T, Kirman CR, Aylward LL, Budinsky RA, Rowlands JC, Long TF. Estimates of Cancer Potency of 2,3,4,7,8-Pentachlorodibenzofuran Using Both Nonlinear and Linear Approaches. Toxicol Sci 2008; 106:519-37. [DOI: 10.1093/toxsci/kfn176] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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