Department of Endocrinology, University Hospital Center (CHU) of Nice, Nice, France.
Thyroid. 2011 Oct;21(10):1133-41. doi: 10.1089/thy.2010.0459. Epub 2011 Aug 29.
In utero exposure to environmental chemicals can result in reproductive toxicity via endocrine disruption mechanisms. Whether some of those contaminants also have an impact on fetal thyroid function or pathways, and, thus, potentially on neuropsychological development, is still debated.
We used samples from a cord blood (CB) and milk bank, established for a research on cryptorchidism and xenobiotic exposure to compounds known for their anti-androgenic and/or estrogenic activity, to study CB thyroid tests and their correlation with CB and milk xenobiotics concentrations in boys born in Nice area.
No difference was found in thyroid tests between 60 cryptorchid boys and 76 matched controls (median thyroid stimulating hormone 5.97 vs. 6.55 mUI/L, free thyroxine [fT4] 13.1 vs. 12.9 pmol/L, free triiodothyronine [fT3] 1.9 vs. 2.1 pmol/L), with no influence of season of birth, gestational age, maternal smoking, or mode of delivery (except for higher fT4 in control boys born vaginally). FT4 was correlated with fetal growth only in cryptorchid boys. Since we had previously shown differences between cryptorchid and controls exposure, we studied correlations of thyroid tests with xenobiotics in control boys only. All tested CB or maternal milk was contaminated by one or more selected xenobiotics, mainly polychlorinated biphenyls (PCBs), dichloro diphenyl dichloroethylène (DDE), dibutylphthalate, hexachlorobenzene, and bisphenol A. We found a significant negative correlation between fT4 and concentrations of PCB118, PC180, and DDE in milk (respectively r = -0.342, p < 0.03, r = -0.296, p = 0.031, r = -0.315, p = 0.016), persisting after adjustment for mode of delivery. There was a significant positive correlation of fT3 with milk concentrations of PCB138, PCB153, ΣPCB, and dibutylphthalate (respectively r = 0.31, p = 0.016, r = 0.28, p = 0.029; r = 0.34, p = 0.0079 and r = 0.272, p = 0.0295), with a trend for PCB180 (r = 0.259, p = 0.061). There was no correlation of thyroid stimulating hormone with any of the measured xenobiotics, except for a weak negative trend with CB bisphenol A (r = -0.25, p = 0.077).
CB thyroid tests are within normal range in cryptorchid boys, similar to controls. Our data in controls suggest a possible weak correlation between in utero exposure to some xenobiotics (PCBs, DDE) and fT3 and fT4 CB concentrations, with usually negative correlations with fT4 and positive with fT3 concentrations, which we speculate could suggest an impact on deiodinases.
宫内暴露于环境化学物质会通过内分泌干扰机制导致生殖毒性。一些污染物是否也会影响胎儿甲状腺功能或途径，从而可能影响神经心理发育，这仍存在争议。
我们使用了来自脐带血（CB）和母乳银行的样本，该银行是为研究隐睾症和已知具有抗雄激素和/或雌激素活性的化合物的外源性物质暴露而建立的，以研究男孩的 CB 甲状腺测试及其与尼斯地区出生的男孩的 CB 和母乳中污染物浓度的相关性。
60 名隐睾男孩和 76 名匹配对照组之间的甲状腺测试无差异（中位数甲状腺刺激激素 5.97 vs. 6.55 mUI/L，游离甲状腺素 [fT4] 13.1 vs. 12.9 pmol/L，游离三碘甲状腺原氨酸 [fT3] 1.9 vs. 2.1 pmol/L），与出生季节、胎龄、母亲吸烟或分娩方式无关（除了对照组阴道分娩的男孩 fT4 更高）。FT4 仅与隐睾男孩的胎儿生长有关。由于我们之前已经显示出隐睾症和对照组之间的暴露差异，因此我们仅在对照组男孩中研究了甲状腺测试与外源性物质的相关性。所有测试的 CB 或母乳均受到一种或多种选定的外源性物质的污染，主要是多氯联苯（PCBs）、二氯二苯二氯乙烷（DDE）、邻苯二甲酸二丁酯、六氯苯和双酚 A。我们发现 fT4 与母乳中 PCB118、PC180 和 DDE 的浓度呈显著负相关（分别 r = -0.342，p < 0.03，r = -0.296，p = 0.031，r = -0.315，p = 0.016），在调整分娩方式后仍然存在。fT3 与母乳中 PCB138、PCB153、ΣPCB 和邻苯二甲酸二丁酯的浓度呈显著正相关（分别 r = 0.31，p = 0.016，r = 0.28，p = 0.029；r = 0.34，p = 0.0079 和 r = 0.272，p = 0.0295），与 PCB180 呈趋势（r = 0.259，p = 0.061）。甲状腺刺激激素与任何测量的外源性物质均无相关性，除了与 CB 双酚 A 呈弱负相关（r = -0.25，p = 0.077）。
隐睾症男孩的 CB 甲状腺测试在正常范围内，与对照组相似。我们在对照组中的数据表明，宫内暴露于某些外源性物质（PCBs、DDE）与 CB fT3 和 fT4 浓度之间可能存在较弱的相关性，通常与 fT4 呈负相关，与 fT3 呈正相关，我们推测这可能表明对外源性物质的影响。
