Annette Vriens1, Tim S Nawrot2, Willy Baeyens3, Elly Den Hond4, Liesbeth Bruckers5, Adrian Covaci6, Kim Croes3, Sam De Craemer3, Eva Govarts7, Nathalie Lambrechts7, Ilse Loots8, Vera Nelen4, Martien Peusens1, Stefaan De Henauw9, Greet Schoeters7, Michelle Plusquin10. 1. Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium. 2. Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium; School of Public Health, Occupational & Environmental Medicine, Leuven University, Leuven, Belgium. 3. Department of Analytical and Environmental Chemistry, Vrije Universiteit Brussel, Brussels, Belgium. 4. Provincial Institute for Hygiene, Antwerp, Belgium. 5. Interuniversity Institute for Biostatistics and Statistical Bioinformatics, Hasselt University, Diepenbeek, Belgium. 6. Toxicological Centre, University of Antwerp, Antwerp, Belgium. 7. Environmental Risk and Health, Flemish Institute for Technological Research (VITO), Mol, Belgium. 8. Faculty of Social Sciences and IMDO-Institute, University of Antwerp, Antwerp, Belgium. 9. Department of Public Health, Ghent University, Ghent, Belgium; Department of Food Safety and Food Quality, Ghent University, Ghent, Belgium. 10. Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium. Electronic address: michelle.plusquin@uhasselt.be.
Abstract
BACKGROUND: Placental mitochondrial DNA (mtDNA) content can be indicative of oxidative damage to the placenta during fetal development and is responsive to external stressors. In utero exposure to environmental pollutants that may influence placental mtDNA needs further exploration. OBJECTIVES: We evaluated if placental mtDNA content is altered by environmental pollution in newborns and identified pollutants independently associated to alterations in placental mtDNA content. METHODS: mtDNA content was measured in placental tissue of 233 newborns. Four perfluoroalkyl compounds and nine organochlorine compounds were quantified in cord blood plasma samples and six toxic metals in whole cord blood. We first applied a LASSO (least absolute shrinkage and selection operator) penalized regression model to identify independent associations between environmental pollutants and placental mtDNA content, without penalization of several covariates. Then adjusted estimates were obtained using an ordinary least squares (OLS) regression model evaluating the pollutants' association with placental mtDNA content, adjusted for several covariates. RESULTS: Based on LASSO penalized regression, oxychlordane, p,p'-dichlorodiphenyldichloroethylene, β-hexachlorocyclohexane, perfluorononanoic acid, arsenic, cadmium and thallium were identified to be independently associated with placental mtDNA content. The OLS model showed a higher placental mtDNA content of 2.71% (95% CI: 0.3 to 5.2%; p=0.03) and 1.41% (0.1 to 2.8%, p=0.04) for a 25% concentration increase of respectively cord blood β-hexachlorocyclohexane and arsenic. For a 25% concentration increase of cord blood thallium, a 4.88% lower placental mtDNA content (95% CI: -9.1 to -0.5%, p=0.03) was observed. CONCLUSION: In a multi-pollutant approach, low fetal exposure levels of environmental organic and inorganic pollutants might compromise placental mitochondrial function as exemplified in this study by alterations in mtDNA content.
BACKGROUND: Placental mitochondrial DNA (mtDNA) content can be indicative of oxidative damage to the placenta during fetal development and is responsive to external stressors. In utero exposure to environmental pollutants that may influence placental mtDNA needs further exploration. OBJECTIVES: We evaluated if placental mtDNA content is altered by environmental pollution in newborns and identified pollutants independently associated to alterations in placental mtDNA content. METHODS: mtDNA content was measured in placental tissue of 233 newborns. Four perfluoroalkyl compounds and nine organochlorine compounds were quantified in cord blood plasma samples and six toxic metals in whole cord blood. We first applied a LASSO (least absolute shrinkage and selection operator) penalized regression model to identify independent associations between environmental pollutants and placental mtDNA content, without penalization of several covariates. Then adjusted estimates were obtained using an ordinary least squares (OLS) regression model evaluating the pollutants' association with placental mtDNA content, adjusted for several covariates. RESULTS: Based on LASSO penalized regression, oxychlordane, p,p'-dichlorodiphenyldichloroethylene, β-hexachlorocyclohexane, perfluorononanoic acid, arsenic, cadmium and thallium were identified to be independently associated with placental mtDNA content. The OLS model showed a higher placental mtDNA content of 2.71% (95% CI: 0.3 to 5.2%; p=0.03) and 1.41% (0.1 to 2.8%, p=0.04) for a 25% concentration increase of respectively cord blood β-hexachlorocyclohexane and arsenic. For a 25% concentration increase of cord blood thallium, a 4.88% lower placental mtDNA content (95% CI: -9.1 to -0.5%, p=0.03) was observed. CONCLUSION: In a multi-pollutant approach, low fetal exposure levels of environmental organic and inorganic pollutants might compromise placental mitochondrial function as exemplified in this study by alterations in mtDNA content.
Authors: Yinnan Zheng; Cuilin Zhang; Marc G Weisskopf; Paige L Williams; Birgit Claus Henn; Patrick J Parsons; Christopher D Palmer; Germaine M Buck Louis; Tamarra James-Todd Journal: Int J Hyg Environ Health Date: 2019-12-28 Impact factor: 5.840