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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, Yiyi LU ; Wahlberg, Karin LU ; Love, Tanzy M.; Watson, Gene E.; Yeates, Alison J.; Mulhern, Maria S.; McSorley, Emeir M.; Strain, J. J.; Davidson, Philip W. and Shamlaye, Conrad F., et al. (2019) In Environment International 124. p.278-283
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... (More)

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.

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published
subject
keywords
Mercury, Methylmercury, Mitochondrial DNA, Polyunsaturated fatty acids
in
Environment International
volume
124
pages
6 pages
publisher
Elsevier
external identifiers
  • scopus:85060032569
ISSN
0160-4120
DOI
10.1016/j.envint.2019.01.019
language
English
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yes
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f975ed22-ff58-4f93-abda-86193ccec85e
date added to LUP
2019-01-28 12:29:22
date last changed
2019-02-20 11:44:48
@article{f975ed22-ff58-4f93-abda-86193ccec85e,
  abstract     = {<p>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.</p>},
  author       = {Xu, Yiyi and Wahlberg, Karin and Love, Tanzy M. and Watson, Gene E. and Yeates, Alison J. and Mulhern, Maria S. and McSorley, Emeir M. and Strain, J. J. and Davidson, Philip W. and Shamlaye, Conrad F. and Rand, Matthew D. and Myers, G. J. and van Wijngaarden, Edwin and Broberg, Karin},
  issn         = {0160-4120},
  keyword      = {Mercury,Methylmercury,Mitochondrial DNA,Polyunsaturated fatty acids},
  language     = {eng},
  pages        = {278--283},
  publisher    = {Elsevier},
  series       = {Environment International},
  title        = {Associations of blood mercury and fatty acid concentrations with blood mitochondrial DNA copy number in the Seychelles Child Development Nutrition Study},
  url          = {http://dx.doi.org/10.1016/j.envint.2019.01.019},
  volume       = {124},
  year         = {2019},
}