Malondialdehyde in Exhaled Breath Condensate and in Plasma Following Highway Commutes

Abstract

Malondialdehyde in Exhaled Breath Condensate and in Plasma Following Highway CommutesAbstract Number:1645 Rachel Golan*, Roby Greenwald, Brent Early-Jones, Andrea Winquist, Priya Kewada, Amit U Raysoni, W. Dana Flanders, Stefanie Sarnat, Fuyuen Yip, Jeremy A Sarnat Rachel Golan* Emory University, United States, E-mail Address: [email protected] Search for more papers by this author , Roby Greenwald Emory University Search for more papers by this author , Brent Early-Jones Emory University Search for more papers by this author , Andrea Winquist Emory University Search for more papers by this author , Priya Kewada Emory University Search for more papers by this author , Amit U Raysoni Emory University Search for more papers by this author , W. Dana Flanders Emory University Search for more papers by this author , Stefanie Sarnat Emory University Search for more papers by this author , Fuyuen Yip Centers for Disease Control and Prevention Search for more papers by this author , and Jeremy A Sarnat Emory University Search for more papers by this author AbstractBackground: Malondialdehyde (MDA), a product of lipid peroxidation, is recognized as a biomarker for air pollution-related oxidative stress (OS). Whether respiratory tract OS is predictive of or associated with corresponding systemic OS, however, is not clear.Methods: In the Atlanta Commuters Exposures (ACE) Study, 42 non-smoking adults, with or without asthma, conducted two, 2h scripted morning car commutes. Routes included heavily used commuting roadways with gasoline and diesel engine vehicles. Exhaled breath condensate (EBC) was collected pre-commute, immediately following (0h) and at 3 hourly intervals post commute. Blood samples were collected pre-commute and at noon. We sampled in-vehicle concentrations of size-resolved particulate matter (PM) and organic and elemental species. Mixed effect regression models were used to examine the associations between in-vehicle PM and EBC and plasma MDA.Results: Participants with asthma had higher baseline plasma MDA. Plasma MDA significantly increased post commute (6%, p = 0.001). EBC MDA increased post commute (8.9%, p=0.3) and decreased in the following hourly measurements towards baseline levels. Weak correlations (Pearson’s r range: 0.02-0.06) were observed between EBC and plasma MDA. Regression results indicated that increases in both EBC MDA (p=0.04) and plasma MDA (p=0.03) were associated with particle-bound polycyclic aromatic hydrocarbons (PAHs). Plasma MDA was further associated with fine PM (p=0.03).Conclusions: Commuting was associated with mild, increased lipid peroxidation measurable in both plasma and EBC MDA in the ACE study. These findings support the use of plasma MDA as a biomarker of systemic oxidative stress and EBC MDA as a biomarker for oxidative stress in the respiratory tract.Results concerning the relationship between pulmonary contributions to corresponding systemic oxidative stress response after commuting was not conclusive and deserves further investigation.