Published ahead of print on January 8, 2009, doi:10.1164/rccm.200807-1097OC
© 2009 American Thoracic Society doi: 10.1164/rccm.200807-1097OC
Rapid DNA Methylation Changes after Exposure to Traffic Particles1 Laboratory of Environmental Epigenetics, Department of Environmental and Occupational Health, University of Milan & IRCCS Maggiore Hospital, Mangiagalli and Regina Elena Foundation, Milan, Italy; 2 Department of Environmental Health, Harvard School of Public Health; 3 Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School; and 4 VA Normative Aging Study, Veterans Affairs Boston Healthcare System and the Department of Medicine, Boston University School of Medicine, Boston, Massachusetts Correspondence and requests for reprints should be addressed to Andrea Baccarelli, M.D., Ph.D., Laboratory of Environmental Epigenetics, Department of Environmental and Occupational Health, University of Milan, Via San Barnaba 8, 20122 Milan, Italy. E-mail: andrea.baccarelli{at}unimi.it Rationale: Exposure to particulate air pollution has been related to increased hospitalization and death, particularly from cardiovascular disease. Lower blood DNA methylation content is found in processes related to cardiovascular outcomes, such as oxidative stress, aging, and atherosclerosis. Objectives: We evaluated whether particulate pollution modifies DNA methylation in heavily methylated sequences with high representation throughout the human genome.
Methods: We measured DNA methylation of long interspersed nucleotide element (LINE)-1 and Alu repetitive elements by quantitative polymerase chain reaction–pyrosequencing of 1,097 blood samples from 718 elderly participants in the Boston area Normative Aging Study. We used covariate-adjusted mixed models to account for within-subject correlation in repeated measures. We estimated the effects on DNA methylation of ambient particulate pollutants (black carbon, particulate matter with aerodynamic diameter Measurements and Main Results: Repetitive element DNA methylation varied in association with time-related variables, such as day of the week and season. LINE-1 methylation decreased after recent exposure to higher black carbon (β = –0.11; 95% confidence interval [CI], –0.18 to –0.04; P = 0.002) and PM2.5 (β = –0.13; 95% CI, –0.19 to –0.06; P < 0.001 for the 7-d moving average). In two-pollutant models, only black carbon, a tracer of traffic particles, was significantly associated with LINE-1 methylation (β = –0.09; 95% CI, –0.17 to –0.01; P = 0.03). No association was found with Alu methylation (P > 0.12). Conclusions: We found decreased repeated-element methylation after exposure to traffic particles. Whether decreased methylation mediates exposure-related health effects remains to be determined.
Key Words: epigenetic processes • air pollution • inhalation exposure • interspersed repetitive sequences
Related articles in AJRCCM:
This article has been cited by other articles:
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
2.5 µm [PM2.5], or sulfate) in multiple time windows (4 h to 7 d) before the examination. We estimated standardized regression coefficients (β) expressing the fraction of a standard deviation change in DNA methylation associated with a standard deviation increase in exposure. 
