Table_1_Metabolomic Markers of Phthalate Exposure in Plasma and Urine of Pregnant Women.docx

Phthalates are known endocrine disruptors and found in almost all people with several associated adverse health outcomes reported in humans and animal models. Limited data are available on the relationship between exposure to endocrine disrupting chemicals and the human metabolome. We examined the relationship of metabolomic profiles in plasma and urine of 115 pregnant women with eleven urine phthalate metabolites measured at 26 weeks of gestation to identify potential biomarkers and relevant pathways. Targeted metabolomics was performed by selected reaction monitoring liquid chromatography and triple quadrupole mass spectrometry to measure 415 metabolites in plasma and 151 metabolites in urine samples. We have chosen metabolites with the best defined peaks for more detailed analysis (138 in plasma and 40 in urine). Relationship between urine phthalate metabolites and concurrent metabolomic markers in plasma and urine suggested potential involvement of diverse pathways including lipid, steroid, and nucleic acid metabolism and enhanced inflammatory response. Most of the correlations were positive for both urine and plasma, and further confirmed by regression and PCA analysis. However, after the FDR adjustment for multiple comparisons, only 9 urine associations remained statistically significant (q-values 0.0001–0.0451), including Nicotinamide mononucleotide, Cysteine T2, Cystine, and L-Aspartic acid. Additionally, we found negative associations of maternal pre-pregnancy body mass index (BMI) with more than 20 metabolomic markers related to lipid and amino-acid metabolism and inflammation pathways in plasma (p = 0.01–0.0004), while Mevalonic acid was positively associated (p = 0.009). Nicotinic acid, the only significant metabolite in urine, had a positive association with maternal BMI (p = 0.002). In summary, when evaluated in the context of metabolic pathways, the findings suggest enhanced lipid biogenesis, inflammation and altered nucleic acid metabolism in association with higher phthalate levels. These results provide new insights into the relationship between phthalates, common in most human populations, and metabolomics, a novel approach to exposure and health biomonitoring.

邻苯二甲酸酯（Phthalates）是一类公认的内分泌干扰物（endocrine disruptors），几乎在所有人群中均可检出，且在人类及动物模型中均有多种相关不良健康结局被报道。目前关于内分泌干扰化学物（endocrine disrupting chemicals）暴露与人类代谢组（metabolome）之间关联的研究数据较为有限。本研究针对115名妊娠26周的孕妇采集的血浆与尿液样本，分析其代谢组学特征与11种尿液邻苯二甲酸酯代谢物之间的关联，旨在识别潜在生物标志物及相关通路。采用液相色谱-选择反应监测（selected reaction monitoring）结合三重四极杆质谱（triple quadrupole mass spectrometry）的靶向代谢组学（targeted metabolomics）方法，分别定量检测血浆样本中的415种代谢物与尿液样本中的151种代谢物。本研究进一步筛选出峰形最优的代谢物进行深入分析（血浆中138种、尿液中40种）。尿液邻苯二甲酸酯代谢物与血浆、尿液中同时检测的代谢组学标志物之间的关联分析显示，脂质代谢、类固醇代谢、核酸代谢以及炎症反应增强等多种通路可能参与其中。多数尿液与血浆中的关联均呈正相关，并通过回归分析与主成分分析（Principal Component Analysis, PCA）得到进一步验证。然而，经多重比较的错误发现率（false discovery rate, FDR）校正后，仅9种尿液代谢物与邻苯二甲酸酯代谢物的关联仍具有统计学显著性（q值范围为0.0001~0.0451），包括烟酰胺单核苷酸（Nicotinamide mononucleotide）、半胱氨酸T2（Cysteine T2）、胱氨酸（Cystine）及L-天冬氨酸（L-Aspartic acid）。此外，本研究还发现，母亲孕前体重指数（BMI）与血浆中20余种与脂质代谢、氨基酸代谢及炎症通路相关的代谢组学标志物呈负相关（P值范围为0.01~0.0004），而甲羟戊酸（Mevalonic acid）则呈正相关（P=0.009）。尿液中唯一具有统计学显著性的代谢物烟酸（Nicotinic acid）与母亲BMI呈正相关（P=0.002）。综上，从代谢通路的角度分析，本研究结果表明，邻苯二甲酸酯水平升高与脂质生物合成增强、炎症反应加剧及核酸代谢改变存在关联。邻苯二甲酸酯在绝大多数人群中普遍存在，本研究结果为邻苯二甲酸酯暴露与代谢组学之间的关联提供了新的见解，同时也为暴露与健康生物监测提供了一种新型研究手段。