Exhaled breath malondialdehyde as a biomarker of effect of exposure to traffic-related air pollution Open Access

Li, Weiwei (2012)

Permanent URL: https://etd.library.emory.edu/concern/etds/6969z1826?locale=en
Published

Abstract

Background: Traffic-related air pollution induces lung inflammation and oxidative stress. Noninvasive measurement of biomarker such as malondialdehyde (MDA) in exhaled breath condensate (EBC) is particularly useful for evaluating the role of oxidative stress and inflammation in acute responses to exposures that occur in vehicles. Objectives: To examine whether short-term exposure to traffic-related air pollutants affects MDA levels in EBC as a biomarker of oxidative stress. Methods: 21 healthy subjects and 21 asthmatic subjects are recruited in this study. All subjects operated vehicles for two hours during the morning rush period on scripted roadways in the Atlanta region. Each vehicle is equipped with instrumentation to monitor concentrations of air pollutants. EBC samples are collected pre and post-exposure by cooling down the exhaled breath in a refrigerated collecting device. The concentrations of MDA in EBC were measured by high-performance liquid chromatography (HPLC) fluorescence detection after the EBC samples were derived with thiobarbituric acid (TBA). Statistic approaches used to analyze the changes of MDA levels include repeated measures ANOVA and t-test. Mixed effect regression models are used to analyze the associations between in-vehicle pollutants (BC and PAHs) and the changes of MDA levels during the prescribed commute. Results: EBC-MDA levels increased immediately after exposure to the 2-hour commuting. From one hour after the commute, MDA levels decreased to constant values similar as the MDA levels one day before the commute. The changes of MDA levels for asthmatic subjects are more significant than healthy subjects. Moreover, there are several significant associations between the in-vehicle pollutants (especially PAHs) and the changes of MDA levels. Discussion: MDA in EBC is a useful biomarker of effect of exposure to traffic-related air pollutants. This marker of oxidative stress is a promising tool in future studies of traffic-related air pollution.


Exhaled breath malondialdehyde as a biomarker of effect of exposure to traffic-related air pollution


Bachelor of Science
Tsinghua University
2010
Thesis Committee Chair: Roby Greenwald
A thesis submitted to the Faculty of the
Rollins School of Public Health of Emory University
in partial fulfillment of the requirements for the degree of
Master of Public Health
in Environmental Health
2012

Table of Contents


TABLE of CONTENTS

INTRODUCTION...1
METHODS...4

Subjects...4
Study design...5
EBC collection...5
Malondialdehyde Analysis in EBC...7
Data Analysis...9

RESULTS...11

Summary statistics...11
Differences of MDA levels between healthy subjects and asthmatic subjects...14
Changes of MDA levels for healthy subjects and asthmatic subjects...15
Changes of MDA levels in effect of exposure to the commute...19
Associations between air pollutants and MDA levels...21

DISCUSSION...23

Explanation of increased MDA levels...23
Changes of MDA levels between pre and post-exposure...24
Different changes of MDA levels between healthy subjects and asthmatic subjects...26
Differences of MDA levels between healthy subjects and asthmatic subjects...26
Methodology limitation...28

CONCLUSION...30
REFFERENCES...31

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