應用核磁共振氫譜技術探討孩童代謝體特徵與全氟碳化物及鄰苯二甲酸酯類之環境暴露之關聯研究

Abstract

全氟碳化物 (Perfluoroalkyl substances, PFASs) 及鄰苯二甲酸酯類 (phthalates, PAEs) 皆經常被使用於工業用品及消費產品中，因此這些物質能在人體中被廣泛地偵測到。近年來許多流行病學研究開始探討人體暴露到PFASs及PAEs對於健康效應的影響，然而這些流行病學調查尚無法針對這些化學物質可能的影響機制與所造成的健康效應之間提供一個完整且清楚的關聯性。因此本研究的目的是利用代謝體學的方法來了解PFASs及PAEs之環境暴露對於兒童產生不良健康效應的可能影響機制，以期了解在成人中有顯著健康效應之前可能的軌跡。 本研究納入了290位來自台灣出生世代研究 (Taiwan Birth Panel Study, TBPS)與台灣早期追蹤研究 (Taiwan Early-Life Cohort, TEC) 的孩童 (8~10歲)，以高效能液相層析串聯質譜儀分析其生物液中的13種PFASs與12種PAEs之代謝物濃度，並應用質子核磁共振儀結合多變量統計模式與複線性迴歸分析來探討孩童暴露到不同濃度的PFASs及PAEs時，其血清內生性代謝物的特定變化情形，此外相關的問卷資料也被納入分析以釐清代謝體的改變與這些化學物質的不同暴露濃度之可能關聯。 在此研究結果中顯示，孩童暴露到不同濃度之PFUnDA (perfluoro-n-undecanoic acid)、PFTrDA (perfluoro-n-tridecanoic acid)、MiBP (mono-isobutyl phthalate)及總DEHP (di(2-ethylhexyl) phthalate)後被發現會有不同的內生性代謝物變化趨勢，並且孩童的血清代謝體變化也會與其居住地、性別及身體質量指數有關。有三種血清代謝物與多種暴露物質相關: 極低密度脂蛋白(VLDL)與PFOS (perfluoro-n-octyl sulfonate、PFNA (perfluoro-n-nonanoic acid)、MiBP及DEHP有關，指出可能對於胰島素抗性與脂蛋白代謝造成影響；榖胺醯胺 (glutamine)與PFOS、PFNA及DEHP 有關，可能與胰島素分泌與神經傳導有連結；鯊肌醇 (scyllo-inositol)與PFNA、 MnBP (mono-n-butyl phthalate)及DEHP有關，可能會改變肝臟醣酵解與神經發育。此外，乙醯基糖蛋白 (glycoprotein acetyls) 只在居住於工業地區之族群中發現與MiBP有關，可能指出與系統性發炎反應有關。 上述結論中，極低密度脂蛋白 (VLDL)、榖胺醯胺 (glutamine)、鯊肌醇 (scyllo－inositol) 及乙醯基糖蛋白 (glycoprotein acetyls ) 的改變可能與數種PFASs與PAEs暴露相關，顯示了其可能對孩童健康造成的不良影響。此研究辨認由環境暴露所造成的代謝擾動及建議出可能造成的不良健康效應及可能影響的生物功能，代謝體學是一個有效的方法探討複雜暴露的可能健康效應。

Perfluoroalkyl substances (PFASs) and phthalates (PAEs) are both commonly used in industrial applications and consumer products, and therefore are detectable in the human samples widely. Recent epidemiologic studies have been focused on some health effects of PFAS and PAE exposure in the human. However, these epidemiologic surveys still cannot provide complete and clear association to link possible mechanisms of these chemicals with their adverse health effects. The purpose of this study is to understand possible mechanisms of environmental exposure to PFASs and PAEs in causing adverse health effects in children, who can provide a trajectory for significant effects in adulthood, by using metabolomic approach. 290 Taiwanese children (8-10 years) from Taiwan Birth Panel Study (TBPS) and Taiwan Early-Life Cohort (TEC) were included in this study. Thirteen PFASs and twelve phthalate metabolites were analyzed in their biofluids by high performance liquid chromatography/ tandem mass spectrometry. Proton nuclear magnetic resonance spectrometry combined with multivariate statistical methods and multiple linear regression models were applied to examine serum metabolic patterns in children exposed to different levels of PFASs and PAEs. Moreover, questionnaire data were collected to associate with the changes of metabolome and exposure levels of these chemicals. In our results, different metabolic patterns were discovered in children exposed to different levels of PFUnDA (perfluoro-n-undecanoic acid), PFTrDA (perfluoro-n-tridecanoic acid), MiBP (mono-isobutyl phthalate) and ΣDEHP (di(2-ethylhexyl) phthalate). In addition, the metabolomes of children's serum were associated with their residential regions, gender and their body mass indexes. Three serum metabolites were associated with multiple exposures: VLDL level was associated with PFOS (perfluoro-n-octyl sulfonate, PFNA (perfluoro-n-nonanoic acid), MiBP and DEHP levels, which may indicate the possible effects on insulin resistance and lipoprotein metabolism; glutamine level was associated with PFOS, PFNA and DEHP exposure, which may be linked with alteration of insulin secretion and neurological system; scyllo-inositol, associated with PFNA, MnBP (mono-n-butyl phthalate) and DEHP exposure, may alter liver glycolysis and neurodevelopment. Furthermore, glycoprotein acetyls level associated with MiBP exposure, which was only discovered in industrial region, may indicate the response of systematic inflammation. In conclusion, VLDL, glutamine, scyllo-inositol and glycoprotein acetyls were found to be associated with several PFAS and PAE exposures, indicating the possible adverse effects on children's health. This study shows that metabolomics is a powerful approach to identify metabolic perturbation caused by environmental exposure and to suggest possible effects on biological function of these chemicals and their possible adverse health effects.