Thyroid hormone metabolism and environmental chemical exposure

Environmental Health

Research

Wim MC van Aalderen¹  Tom Vulsma¹  Marike M Leijs²  Gavin W ten Tusscher³  Janna G Koppe⁴  Pim de Voogt⁵  Claudia Mosoiu⁶  Gemma Calamandrei⁷  Kees Olie⁸  Tom van Teunenbroek⁹  Alena Bartonova^1,10  Horacio Riojas-Rodriguez^1,11  Martin Krayer von Krauss^1,12 

[1] Department of Paediatrics and Neonatology, Emma Children’s Hospital Academic Medical Centre, Amsterdam, The Netherlands;Department of Paediatrics and Neonatology, Emma Children’s Hospital Academic Medical Centre, Amsterdam, The Netherlands;IBED/ESS, University of Amsterdam, Amsterdam, The Netherlands;University Hospital Aachen RWTH, Department of Dermatology, Pauwelstrasse 30, 52074, Aachen, Germany;Department of Paediatrics and Neonatology, Westfriesgasthuis, Maelsonstraat 3, 1624, NP Hoorn, The Netherlands;Ecobaby Foundation, Hollandstraat 6, 3634, AT Loenersloot, The Netherlands;IBED/ESS, University of Amsterdam, Amsterdam, The Netherlands;KWR Watercycle Research, POBox 1072, 3430, BB Nieuwegein, The Netherlands;Institute of Food Bioresources (IBA), Bucharest, Romania;Istituto Superiore di Sanita, Rome, Italy;KWR Watercycle Research, POBox 1072, 3430, BB Nieuwegein, The Netherlands;Ministry of Housing, Spatial Planning and the Environment, The Hague, The Netherlands;NILU – Norwegian Institute for Air Research, Kjeller, Norway;National Institute of Public Health, Cernavaca, Morelos, Mexico;WHO, Regional Office for Europe, Copenhgen, Scherfigsvej 8, Denmark;

关键词: Thyroid Hormone;    Thyroid Stimulate Hormone;    Thyroid Stimulate Hormone Level;    Brominate Flame Retardant;    Thyroid Hormone Metabolism;   

DOI  :  10.1186/1476-069X-11-S1-S10

来源: Springer

【 摘 要 】

BackgroundPolychlorinated dioxins and –furans (PCDD/Fs) and polychlorinated-biphenyls (PCBs) are environmental toxicants that have been proven to influence thyroid metabolism both in animal studies and in human beings. In recent years polybrominated diphenyl ethers (PBDEs) also have been found to have a negative influence on thyroid hormone metabolism. The lower brominated flame retardants are now banned in the EU, however higher brominated decabromo-diphenyl ether (DBDE) and the brominated flame retardant hexabromocyclododecane (HBCD) are not yet banned. They too can negatively influence thyroid hormone metabolism. An additional brominated flame retardant that is still in use is tetrabromobisphenol-A (TBBPA), which has also been shown to influence thyroid hormone metabolism.Influences of brominated flame retardants, PCDD/F’s and dioxin like-PCBs (dl-PCB’s) on thyroid hormone metabolism in adolescence in the Netherlands will be presented in this study and determined if there are reasons for concern to human health for these toxins. In the period 1987-1991, a cohort of mother-baby pairs was formed in order to detect abnormalities in relation to dioxin levels in the perinatal period. The study demonstrated that PCDD/Fs were found around the time of birth, suggesting a modulation of the setpoint of thyroid hormone metabolism with a higher 3,3’, 5,5’tetrathyroxine (T4) levels and an increased thyroid stimulating hormone (TSH). While the same serum thyroid hormone tests (- TSH and T4) were again normal by 2 years of age and were still normal at 8-12 years, adolescence is a period with extra stress on thyroid hormone metabolism. Therefore we measured serum levels of TSH, T4, 3,3’,5- triiodothyronine (T3), free T4 (FT4), antibodies and thyroxine-binding globulin (TBG) in our adolescent cohort.MethodsVena puncture was performed to obtain samples for the measurement of thyroid hormone metabolism related parameters and the current serum dioxin (PCDD/Fs), PCB and PBDE levels.ResultsThe current levels of T3 were positively correlated to BDE-99. A positive trend with FT4 and BDE-99 was also seen, while a positive correlation with T3 and dl-PCB was also seen. No correlation with TBG was seen for any of the contaminants. Neither the prenatal nor the current PCDD/F levels showed a relationship with the thyroid parameters in this relatively small group.ConclusionOnce again the thyroid hormone metabolism (an increase in T3) seems to have been influenced by current background levels of common environmental contaminants: dl-PCBs and BDE-99. T3 is a product of target organs and abnormalities might indicate effects on hormone transporters and could cause pathology. While the influence on T3 levels may have been compensated, because the adolescents functioned normal at the time of the study period, it is questionable if this compensation is enough for all organs depending on thyroid hormones.

【 授权许可】

Unknown   
© Leijs et al; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.