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Environ Int. 2017 Apr;101:89-95. doi: 10.1016/j.envint.2017.01.010. Epub 2017 Jan 20.

Influence of exposure to coarse, fine and ultrafine urban particulate matter and their biological constituents on neural biomarkers in a randomized controlled crossover study.

Author information

1
Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada. Electronic address: ling.liu@hc-sc.gc.ca.
2
Division of Occupational and Environmental Health, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; Southern Ontario Centre for Atmospheric Aerosol Research (SOCAAR), Toronto, Ontario, Canada.
3
Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada.
4
Division of Occupational and Environmental Health, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
5
The Channing Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
6
Division of Occupational and Environmental Health, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; Southern Ontario Centre for Atmospheric Aerosol Research (SOCAAR), Toronto, Ontario, Canada; Environment and Climate Change Canada, Toronto, Ontario, Canada.
7
Department of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa, USA.
8
Division of Occupational and Environmental Health, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; Southern Ontario Centre for Atmospheric Aerosol Research (SOCAAR), Toronto, Ontario, Canada; Divisions of Occupational Medicine and Respirology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada; Li Ka Shing Knowledge Institute, St Michael's Hospital, Toronto, Ontario, Canada.

Abstract

BACKGROUND:

Epidemiological studies have reported associations between air pollution and neuro-psychological conditions. Biological mechanisms behind these findings are still not clear.

OBJECTIVES:

We examined changes in blood and urinary neural biomarkers following exposure to concentrated ambient coarse, fine and ultrafine particles.

METHODS:

Fifty healthy non-smoking volunteers, mean age 28years, were exposed to coarse (2.5-10μm, mean 213μg/m3) and fine (0.15-2.5μm, mean 238μg/m3) concentrated ambient particles (CAPs), and filtered ambient and/or medical air. Twenty-five participants were exposed to ultrafine CAP (mean size 59.6nm, range 47.0-69.8nm), mean (136μg/m3) and filtered medical air. Exposures lasted 130min, separated by ≥2weeks, and the biological constituents endotoxin and β-1,3-d-glucan of each particle size fraction were measured. Blood and urine samples were collected pre-exposure, and 1-hour and 21-hour post-exposure to determine neural biomarker levels. Mixed-model regressions assessed associations between exposures and changes in biomarker levels.

RESULTS:

Results were expressed as percent change from daily pre-exposure biomarker levels. Exposure to coarse CAP was significantly associated with increased urinary levels of the stress-related biomarkers vanillylmandelic acid (VMA) and cortisol when compared with exposure to filtered medical air [20% (95% confidence interval: 1.0%, 38%) and 64% (0.2%, 127%), respectively] 21hours post-exposure. However exposure to coarse CAP was significantly associated with decreases in blood cortisol [-26.0% (-42.4%, -9.6%) and -22.4% (-43.7%, -1.1%) at 1h and 21h post-exposure, respectively]. Biological molecules present in coarse CAP were significantly associated with blood biomarkers indicative of blood brain barrier integrity. Endotoxin content was significantly associated with increased blood ubiquitin C-terminal hydrolase L1 [UCHL1, 11% (5.3%, 16%) per ln(ng/m3+1)] 1-hour post-exposure, while β-1,3-d-glucan was significantly associated with increased blood S100B [6.3% (3.2%, 9.4%) per ln(ng/m3+1)], as well as UCHL1 [3.1% (0.4%, 5.9%) per ln(ng/m3+1)], one-hour post-exposure. Fine CAP was marginally associated with increased blood UCHL1 when compared with exposure to filtered medical air [17.7% (-1.7%, 37.2%), p=0.07] 21hours post-exposure. Ultrafine CAP was not significantly associated with changes in any blood and urinary neural biomarkers examined.

CONCLUSION:

Ambient coarse particulate matter and its biological constituents may influence neural biomarker levels that reflect perturbations of blood-brain barrier integrity and systemic stress response.

KEYWORDS:

Air pollution; Endotoxin; Neural biomarker; Particulate matter; Randomized controlled crossover trial; β-1,3-d-glucan

PMID:
28117141
PMCID:
PMC5348252
DOI:
10.1016/j.envint.2017.01.010
[Indexed for MEDLINE]
Free PMC Article

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