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Occupational exposure to particles and mitochondrial DNA : Relevance for blood pressure

Xu, Yiyi LU ; Li, Huiqi LU ; Hedmer, Maria LU ; Hossain, Mohammad Bakhtiar; Tinnerberg, Håkan LU ; Broberg, Karin LU and Albin, Maria LU (2017) In Environmental Health: A Global Access Science Source 16(1).
Abstract

Background: Particle exposure is a risk factor for cardiovascular diseases. Mitochondrial DNA (mtDNA) is a primary target for oxidative stress generated by particle exposure. We aimed to elucidate the effects of occupational exposure to particle-containing welding fumes on different biomarkers of mtDNA function, and in turn, explore if they modify the association between particle exposure and cardiovascular response, measured as blood pressure. Methods: We investigated 101 welders and 127 controls (all non-smoking males) from southern Sweden. Personal sampling of the welders’ exposure to respirable dust was performed during work hours (average sampling time: 6.8 h; range: 2.4-8.6 h) and blood pressure was measured once for each subject.... (More)

Background: Particle exposure is a risk factor for cardiovascular diseases. Mitochondrial DNA (mtDNA) is a primary target for oxidative stress generated by particle exposure. We aimed to elucidate the effects of occupational exposure to particle-containing welding fumes on different biomarkers of mtDNA function, and in turn, explore if they modify the association between particle exposure and cardiovascular response, measured as blood pressure. Methods: We investigated 101 welders and 127 controls (all non-smoking males) from southern Sweden. Personal sampling of the welders’ exposure to respirable dust was performed during work hours (average sampling time: 6.8 h; range: 2.4-8.6 h) and blood pressure was measured once for each subject. We measured relative mtDNA copy number by quantitative PCR and methylation of the mitochondrial regulatory region D-loop and the tRNA encoding gene MT-TF by bisulfite-pyrosequencing. We calculated the relative number of unmethylated D-loop and MT-TF as markers of mtDNA function to explore the modification of mtDNA on the association between particle exposure and blood pressure. General linear models were used for statistical analyses. Results: Welders had higher mtDNA copy number (β = 0.11, p = 0.003) and lower DNA methylation of D-loop (β = −1.4, p = 0.002) and MT-TF (β = −1.5, p = 0.004) than controls. Higher mtDNA copy number was weakly associated with higher personal respirable dust exposure among welders with exposure level above 0.7 mg/m3 (β = 0.037, p = 0.054). MtDNA function modified the effect of welding fumes on blood pressure: welders with low mtDNA function had higher blood pressure than controls, while no such difference was found in the group with high mtDNA function. Conclusion: Increased mtDNA copy number and decreased D-loop and MT-TF methylation were associated with particle-containing welding fumes exposure, indicating exposure-related oxidative stress. The modification of mtDNA function on exposure-associated increase in blood pressure may represent a mitochondria-environment interaction.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Blood pressure, Copy number, DNA methylation, Mitochondria, Particle
in
Environmental Health: A Global Access Science Source
volume
16
issue
1
publisher
BioMed Central
external identifiers
  • scopus:85014839705
  • wos:000395975100001
ISSN
1476-069X
DOI
10.1186/s12940-017-0234-4
language
English
LU publication?
yes
id
d05ba3a6-7661-404c-8a0e-d56ec24334ff
date added to LUP
2017-04-10 13:37:55
date last changed
2017-09-18 13:31:50
@article{d05ba3a6-7661-404c-8a0e-d56ec24334ff,
  abstract     = {<p>Background: Particle exposure is a risk factor for cardiovascular diseases. Mitochondrial DNA (mtDNA) is a primary target for oxidative stress generated by particle exposure. We aimed to elucidate the effects of occupational exposure to particle-containing welding fumes on different biomarkers of mtDNA function, and in turn, explore if they modify the association between particle exposure and cardiovascular response, measured as blood pressure. Methods: We investigated 101 welders and 127 controls (all non-smoking males) from southern Sweden. Personal sampling of the welders’ exposure to respirable dust was performed during work hours (average sampling time: 6.8 h; range: 2.4-8.6 h) and blood pressure was measured once for each subject. We measured relative mtDNA copy number by quantitative PCR and methylation of the mitochondrial regulatory region D-loop and the tRNA encoding gene MT-TF by bisulfite-pyrosequencing. We calculated the relative number of unmethylated D-loop and MT-TF as markers of mtDNA function to explore the modification of mtDNA on the association between particle exposure and blood pressure. General linear models were used for statistical analyses. Results: Welders had higher mtDNA copy number (β = 0.11, p = 0.003) and lower DNA methylation of D-loop (β = −1.4, p = 0.002) and MT-TF (β = −1.5, p = 0.004) than controls. Higher mtDNA copy number was weakly associated with higher personal respirable dust exposure among welders with exposure level above 0.7 mg/m3 (β = 0.037, p = 0.054). MtDNA function modified the effect of welding fumes on blood pressure: welders with low mtDNA function had higher blood pressure than controls, while no such difference was found in the group with high mtDNA function. Conclusion: Increased mtDNA copy number and decreased D-loop and MT-TF methylation were associated with particle-containing welding fumes exposure, indicating exposure-related oxidative stress. The modification of mtDNA function on exposure-associated increase in blood pressure may represent a mitochondria-environment interaction.</p>},
  articleno    = {22},
  author       = {Xu, Yiyi and Li, Huiqi and Hedmer, Maria and Hossain, Mohammad Bakhtiar and Tinnerberg, Håkan and Broberg, Karin and Albin, Maria},
  issn         = {1476-069X},
  keyword      = {Blood pressure,Copy number,DNA methylation,Mitochondria,Particle},
  language     = {eng},
  month        = {03},
  number       = {1},
  publisher    = {BioMed Central},
  series       = {Environmental Health: A Global Access Science Source},
  title        = {Occupational exposure to particles and mitochondrial DNA : Relevance for blood pressure},
  url          = {http://dx.doi.org/10.1186/s12940-017-0234-4},
  volume       = {16},
  year         = {2017},
}