Developmental neurotoxicity of organophosphate and novel brominated flame retardants in children

项目摘要 毒理学和流行病学研究表明， 醚（PBDEs），一组在美国和其他地方广泛使用的阻燃剂（FR）。的淘汰 自2004年以来，市场上的多溴二苯醚替代阻燃剂，包括有机磷酸盐阻燃剂 和新型溴化阻燃剂（NBFR）越来越多地添加到消费品中，以满足 易燃性要求。磷酸三（1，3-二氯-2-丙基）酯（TDCPP）和Firemaster® 550（FM 550）是 最常用的替代FR。TDCPP，也称为“氯化tris”，是一种OPFR， 在20世纪70年代添加到儿童睡衣中，但后来由于毒性问题而被删除。 磷酸三苯酯（TPP）和各种TPP类似物是FM 550中的OPFR组分，而2-乙基己基- 2，3，4，5-四溴苯甲酸酯（TBB）和双（2-乙基己基）-2，3，4，5-四溴邻苯二甲酸酯（TBPH）是NBFR FM 550中的组件。据报道，TDCPP、TPP和FM 550可改变甲状腺激素水平， 神经元活力和复制，改变神经元分化，引起异常胚胎发生， 发育，影响神经行为，并改变实验动物的基因表达水平和DNA甲基化。 问题研究与OPFR和NBFR的实验研究证据相比， 了解它们对人类的发育神经毒性。我们建议研究发展 神经毒性的OPFR和NBFR使用基于先天性的健康结果和措施， 环境（HOME）研究，现有的410名儿童出生队列，从产前到12岁， 产前和产后暴露评估、甲状腺激素、认知和行为测试，以及 神经成像数据。我们假设，产前和产后暴露于OPFR和NBFR， 与：1）母体、脐带和儿童血清样本中甲状腺激素水平的改变有关; 2） 儿童认知功能下降; 3）儿童神经行为功能较差; 4）对大脑的不良影响 在12岁时通过神经成像确定结构、组织和功能。拟议的研究将是 第一个全面研究儿童OPFR和NBFR的发育神经毒性。 解决大脑发育的神经内分泌学、神经行为学和神经影像学方面的问题是非常重要的。 对这次调查很有创意。研究结果将对科学界和决策者具有重要价值 评估当前使用的替代FR对发育中的大脑的潜在影响。这项研究高度 与美国国立卫生研究院的使命有关，以确定潜在的化学暴露，破坏大脑 发展和提供重要数据，为预防战略提供信息。

Project Summary Toxicological and epidemiologic studies have shown developmental neurotoxicity of polybrominated diphenyl ethers (PBDEs), a group of flame retardants (FRs) widely used in the U.S. and elsewhere. With the phase-out of PBDEs from the market since 2004, replacement FRs, including organophosphate flame retardants (OPFRs) and novel brominated flame retardants (NBFRs), are increasingly added to consumer products to meet flammability requirement. Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and Firemaster® 550 (FM 550) are the most commonly used replacement FRs. TDCPP, also referred to as “chlorinated tris”, is an OPFR once added to children’s sleepwear in the 1970s but later removed because of toxicity concerns. Triphenylphosphate (TPP) and various TPP analogs are OPFR components in FM 550, while 2-ethylhexyl- 2,3,4,5-tetrabromobenzoate (TBB) and bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate (TBPH) are NBFR components in FM 550. TDCPP, TPP and FM 550 have been reported to alter thyroid hormone levels, reduce neuronal viability and replication, alter neuronal differentiation, cause abnormal embryogenesis and development, affect neurobehavior, and change gene expression levels and DNA methylation in experimental studies. Compared with experimental study evidence of OPFRs and NBFRs, there are significant gaps in our understanding of their developmental neurotoxicity in humans. We propose to examine developmental neurotoxicity of OPFRs and NBFRs using the Cincinnati-based Health Outcomes and Measures of the Environment (HOME) Study, an existing birth cohort of 410 children from prenatal to 12 years of age, with prenatal and postnatal exposure assessment, thyroid hormones, cognitive and behavioral tests, and neuroimaging data. We hypothesize that prenatal and postnatal exposures to OPFRs and NBFRs are associated with: 1) altered thyroid hormone levels in maternal, cord, and childhood serum samples; 2) decreased child cognitive function; 3) poorer child neurobehavioral functioning; and 4) adverse impact on brain structure, organization, and function identified by neuroimaging at age 12 years. The proposed research will be the first to comprehensively study developmental neurotoxicity of both OPFRs and NBFRs in children. Addressing neuroendocrinological, neurobehavioral, and neuroimaging aspects of brain development is highly innovative for this investigation. The findings will be of critical value to scientific community and policy makers evaluating potential impact of current-use replacement FRs on developing brain. The research is highly relevant to the National Institutes of Health mission to identify potential chemical exposures that disrupt brain development and provide critical data to inform prevention strategies.