Associations of blood mercury and fatty acid concentrations with blood mitochondrial DNA copy number in the Seychelles Child Development Nutrition Study

Yivi Xu, Karin Wahlberg, Tanzy M Love, Gene E Watson, Alison J. Yeates, Maria S Mulhern, Emeir M. Mc Sorley, JJ Strain, Philip W Davidson, Conrad F Shamlaye, Matthew D Rand, Gary J Myers, Edwin van Wijngaarden, Karin Broberg

Research output: Contribution to journalArticle

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Abstract

Background: Fish contains methylmercury (MeHg) which can cause oxidative stress and neurodevelopmental toxicity at sufficiently high doses. Fish also contains polyunsaturated fatty acids (PUFA) which have both antioxidant (n-3) and oxidant (n-6) properties. Mitochondrial DNA (mtDNA) is sensitive to oxidative stress but has not been previously studied in relation to MeHg exposure or PUFA status. Objective: To investigate the associations between MeHg exposure and PUFA status during pregnancy with relative mitochondrial DNA copy number (RmtDNAcn) in mothers and their newborns. Methods: In total, 1488 mother-child pairs from the Seychelles Child Development Study Nutrition Cohort 2 were included in this study. Total Hg was measured in maternal blood collected at 28 weeks’ gestation, maternal hair at delivery, and in fetal cord blood. PUFA (n-3 and n-6) were measured only in maternal blood. RmtDNAcn was measured by qPCR in both maternal and cord blood. Results: Increasing maternal blood Hg (β = 0.001, 95%CI: 0.000, 0.002) and n-3 PUFA concentrations (β = 0.183, 95%CI: 0.048, 0.317) were associated with higher maternal RmtDNAcn. Increasing maternal n-6 PUFA (β = −0.103, 95%CI: −0.145, −0.062) and n-6/n-3 ratio (β = −0.011, 95%CI: −0.017, −0.004) were associated with lower maternal RmtDNAcn. Increasing fetal cord blood Hg was associated with lower fetal RmtDNAcn (β = −0.002, 95%CI: −0.004, −0.000). Neither maternal blood Hg nor PUFA status was associated with fetal RmtDNAcn. Conclusions: Our findings suggest that MeHg and PUFA may influence mitochondrial homeostasis although the magnitude of these associations are small. Future studies should confirm the findings and explore the underlying mechanisms.

LanguageEnglish
Pages278-283
Number of pages6
JournalEnvironment International
Volume124
Early online date17 Jan 2019
DOIs
Publication statusPublished - 1 Mar 2019

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child development
mitochondrial DNA
nutrition
fatty acid
blood
pregnancy
mercury
homeostasis
methylmercury
fish
hair
oxidant
antioxidant
toxicity

Keywords

  • Mitochondrial DNA
  • Methylmercury
  • Mercury
  • Polyunsaturated fatty acids

Cite this

Xu, Yivi ; Wahlberg, Karin ; Love, Tanzy M ; Watson, Gene E ; Yeates, Alison J. ; Mulhern, Maria S ; Mc Sorley, Emeir M. ; Strain, JJ ; Davidson, Philip W ; Shamlaye, Conrad F ; Rand, Matthew D ; Myers, Gary J ; van Wijngaarden, Edwin ; Broberg, Karin. / Associations of blood mercury and fatty acid concentrations with blood mitochondrial DNA copy number in the Seychelles Child Development Nutrition Study. In: Environment International. 2019 ; Vol. 124. pp. 278-283.
@article{a7441920e6564fc9809d1a0d7864b7da,
title = "Associations of blood mercury and fatty acid concentrations with blood mitochondrial DNA copy number in the Seychelles Child Development Nutrition Study",
abstract = "Background: Fish contains methylmercury (MeHg) which can cause oxidative stress and neurodevelopmental toxicity at sufficiently high doses. Fish also contains polyunsaturated fatty acids (PUFA) which have both antioxidant (n-3) and oxidant (n-6) properties. Mitochondrial DNA (mtDNA) is sensitive to oxidative stress but has not been previously studied in relation to MeHg exposure or PUFA status. Objective: To investigate the associations between MeHg exposure and PUFA status during pregnancy with relative mitochondrial DNA copy number (RmtDNAcn) in mothers and their newborns. Methods: In total, 1488 mother-child pairs from the Seychelles Child Development Study Nutrition Cohort 2 were included in this study. Total Hg was measured in maternal blood collected at 28 weeks’ gestation, maternal hair at delivery, and in fetal cord blood. PUFA (n-3 and n-6) were measured only in maternal blood. RmtDNAcn was measured by qPCR in both maternal and cord blood. Results: Increasing maternal blood Hg (β = 0.001, 95{\%}CI: 0.000, 0.002) and n-3 PUFA concentrations (β = 0.183, 95{\%}CI: 0.048, 0.317) were associated with higher maternal RmtDNAcn. Increasing maternal n-6 PUFA (β = −0.103, 95{\%}CI: −0.145, −0.062) and n-6/n-3 ratio (β = −0.011, 95{\%}CI: −0.017, −0.004) were associated with lower maternal RmtDNAcn. Increasing fetal cord blood Hg was associated with lower fetal RmtDNAcn (β = −0.002, 95{\%}CI: −0.004, −0.000). Neither maternal blood Hg nor PUFA status was associated with fetal RmtDNAcn. Conclusions: Our findings suggest that MeHg and PUFA may influence mitochondrial homeostasis although the magnitude of these associations are small. Future studies should confirm the findings and explore the underlying mechanisms.",
keywords = "Mitochondrial DNA, Methylmercury, Mercury, Polyunsaturated fatty acids",
author = "Yivi Xu and Karin Wahlberg and Love, {Tanzy M} and Watson, {Gene E} and Yeates, {Alison J.} and Mulhern, {Maria S} and {Mc Sorley}, {Emeir M.} and JJ Strain and Davidson, {Philip W} and Shamlaye, {Conrad F} and Rand, {Matthew D} and Myers, {Gary J} and {van Wijngaarden}, Edwin and Karin Broberg",
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Associations of blood mercury and fatty acid concentrations with blood mitochondrial DNA copy number in the Seychelles Child Development Nutrition Study. / Xu, Yivi; Wahlberg, Karin; Love, Tanzy M; Watson, Gene E; Yeates, Alison J.; Mulhern, Maria S; Mc Sorley, Emeir M.; Strain, JJ; Davidson, Philip W; Shamlaye, Conrad F; Rand, Matthew D; Myers, Gary J; van Wijngaarden, Edwin; Broberg, Karin.

In: Environment International, Vol. 124, 01.03.2019, p. 278-283.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Associations of blood mercury and fatty acid concentrations with blood mitochondrial DNA copy number in the Seychelles Child Development Nutrition Study

AU - Xu, Yivi

AU - Wahlberg, Karin

AU - Love, Tanzy M

AU - Watson, Gene E

AU - Yeates, Alison J.

AU - Mulhern, Maria S

AU - Mc Sorley, Emeir M.

AU - Strain, JJ

AU - Davidson, Philip W

AU - Shamlaye, Conrad F

AU - Rand, Matthew D

AU - Myers, Gary J

AU - van Wijngaarden, Edwin

AU - Broberg, Karin

PY - 2019/3/1

Y1 - 2019/3/1

N2 - Background: Fish contains methylmercury (MeHg) which can cause oxidative stress and neurodevelopmental toxicity at sufficiently high doses. Fish also contains polyunsaturated fatty acids (PUFA) which have both antioxidant (n-3) and oxidant (n-6) properties. Mitochondrial DNA (mtDNA) is sensitive to oxidative stress but has not been previously studied in relation to MeHg exposure or PUFA status. Objective: To investigate the associations between MeHg exposure and PUFA status during pregnancy with relative mitochondrial DNA copy number (RmtDNAcn) in mothers and their newborns. Methods: In total, 1488 mother-child pairs from the Seychelles Child Development Study Nutrition Cohort 2 were included in this study. Total Hg was measured in maternal blood collected at 28 weeks’ gestation, maternal hair at delivery, and in fetal cord blood. PUFA (n-3 and n-6) were measured only in maternal blood. RmtDNAcn was measured by qPCR in both maternal and cord blood. Results: Increasing maternal blood Hg (β = 0.001, 95%CI: 0.000, 0.002) and n-3 PUFA concentrations (β = 0.183, 95%CI: 0.048, 0.317) were associated with higher maternal RmtDNAcn. Increasing maternal n-6 PUFA (β = −0.103, 95%CI: −0.145, −0.062) and n-6/n-3 ratio (β = −0.011, 95%CI: −0.017, −0.004) were associated with lower maternal RmtDNAcn. Increasing fetal cord blood Hg was associated with lower fetal RmtDNAcn (β = −0.002, 95%CI: −0.004, −0.000). Neither maternal blood Hg nor PUFA status was associated with fetal RmtDNAcn. Conclusions: Our findings suggest that MeHg and PUFA may influence mitochondrial homeostasis although the magnitude of these associations are small. Future studies should confirm the findings and explore the underlying mechanisms.

AB - Background: Fish contains methylmercury (MeHg) which can cause oxidative stress and neurodevelopmental toxicity at sufficiently high doses. Fish also contains polyunsaturated fatty acids (PUFA) which have both antioxidant (n-3) and oxidant (n-6) properties. Mitochondrial DNA (mtDNA) is sensitive to oxidative stress but has not been previously studied in relation to MeHg exposure or PUFA status. Objective: To investigate the associations between MeHg exposure and PUFA status during pregnancy with relative mitochondrial DNA copy number (RmtDNAcn) in mothers and their newborns. Methods: In total, 1488 mother-child pairs from the Seychelles Child Development Study Nutrition Cohort 2 were included in this study. Total Hg was measured in maternal blood collected at 28 weeks’ gestation, maternal hair at delivery, and in fetal cord blood. PUFA (n-3 and n-6) were measured only in maternal blood. RmtDNAcn was measured by qPCR in both maternal and cord blood. Results: Increasing maternal blood Hg (β = 0.001, 95%CI: 0.000, 0.002) and n-3 PUFA concentrations (β = 0.183, 95%CI: 0.048, 0.317) were associated with higher maternal RmtDNAcn. Increasing maternal n-6 PUFA (β = −0.103, 95%CI: −0.145, −0.062) and n-6/n-3 ratio (β = −0.011, 95%CI: −0.017, −0.004) were associated with lower maternal RmtDNAcn. Increasing fetal cord blood Hg was associated with lower fetal RmtDNAcn (β = −0.002, 95%CI: −0.004, −0.000). Neither maternal blood Hg nor PUFA status was associated with fetal RmtDNAcn. Conclusions: Our findings suggest that MeHg and PUFA may influence mitochondrial homeostasis although the magnitude of these associations are small. Future studies should confirm the findings and explore the underlying mechanisms.

KW - Mitochondrial DNA

KW - Methylmercury

KW - Mercury

KW - Polyunsaturated fatty acids

U2 - 10.1016/j.envint.2019.01.019

DO - 10.1016/j.envint.2019.01.019

M3 - Article

VL - 124

SP - 278

EP - 283

JO - Environment International

T2 - Environment International

JF - Environment International

SN - 0160-4120

ER -