Department of Epidemiology and Biostatistics, Zhejiang University School of Public Health, Hangzhou, Zhejiang, China; Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles (UCLA), Los Angeles, CA, USA.
Ministry of Education Key Laboratory of Environmental Remediation & Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, China.
Environ Pollut. 2019 Nov;254(Pt A):112900. doi: 10.1016/j.envpol.2019.07.068. Epub 2019 Jul 18.
Breast milk, especially colostrum, is not just a source of nutrients and immune factors for the newborn, but also accumulates environmental persistent pollutants and its diverse microbes affect the early colonization of the newborn's gut. Little is known about associations between environmental pollutants and the microbial composition of human colostrum. We assessed the influence of hexachlorocyclohexane (HCH), a persistent organic pollutant (POP), in colostrums on the microbial composition of human colostrum samples. HCH concentrations in 89 colostrum samples collected from a population living on the easternmost island of China were measured via gas chromatography equipped with mass spectrometer (GC-MS), HCH exposure risks for infants via dietary intake of breast milk were assessed, and for 29 colostrum samples the microbiota were profiled using 16S rRNA gene pyrosequencing to assess the association with HCH exposure levels. Our study confirmed high colostrum exposure levels of total HCHs (12.19 ± 13.68 μg L) in this Chinese population. We predominantly identified Proteobacteria (67.6%) and Firmicutes (25.1%) in colostrum and microbial diversity at the genus level differed between samples with different HCH levels; e.g., Pseudomonas which contains several HCH degrading strains was found in significantly higher abundance in γ-HCH rich samples. Also, microbes that were statistically significantly associated with HCH levels were also highly correlated with each other (false discovery rate (FDR)＜0.01) and clustered in network analysis. Microbial diversity is associated with HCH levels in human colostrum and these associations might be attributable to their HCH degrading ability. These finding provide first insights into the role that environmental persistent pollutants may play in the microbial composition of human colostrum and the colonization of the infant gut.
母乳，尤其是初乳，不仅是新生儿营养和免疫因子的来源，还会积累环境持久性污染物，其多样的微生物会影响新生儿肠道的早期定植。对于环境污染物与人类初乳微生物组成之间的关联，我们知之甚少。我们评估了持久性有机污染物（POP）六氯环己烷（HCH）在初乳中的存在对人类初乳样本微生物组成的影响。采用配备质谱仪的气相色谱法（GC-MS）测量了从中国最东端岛屿的一个人群中采集的 89 份初乳样本中的 HCH 浓度，评估了婴儿通过母乳喂养摄入 HCH 的暴露风险，并对 29 份初乳样本进行了 16S rRNA 基因焦磷酸测序以评估与 HCH 暴露水平的关联。我们的研究证实，该中国人群的初乳中总 HCH 暴露水平较高（12.19±13.68μg/L）。我们主要在初乳中鉴定出了变形菌门（67.6%）和厚壁菌门（25.1%），且不同 HCH 水平的样本在属水平的微生物多样性不同；例如，假单胞菌属中包含几种 HCH 降解菌株，在γ-HCH 丰富的样本中丰度明显更高。此外，与 HCH 水平呈统计学显著相关的微生物彼此之间也高度相关（错误发现率（FDR）＜0.01），并在网络分析中聚类。人类初乳中的 HCH 水平与微生物多样性相关，这些关联可能归因于它们的 HCH 降解能力。这些发现为环境持久性污染物在人类初乳微生物组成和婴儿肠道定植中可能发挥的作用提供了初步见解。
