title: Effects of urban fine particulate matter and ozone on HDL functionality.
abstract: Exposures to ambient particulate matter (PM) are associated with increased morbidity and mortality. PM2.5 (<2.5 μm) and ozone exposures have been shown to associate with carotid intima media thickness in humans. Animal studies support a causal relationship between air pollution and atherosclerosis and identified adverse PM effects on HDL functionality. We aimed to determine whether brief exposures to PM2.5 and/or ozone could induce effects on HDL anti-oxidant and anti-inflammatory capacity in humans.
  
  
  
  Subjects were exposed to fine concentrated ambient fine particles (CAP) with PM2.5 targeted at 150 μg/m(3), ozone targeted at 240 μg/m(3) (120 ppb), PM2.5 plus ozone targeted at similar concentrations, and filtered air (FA) for 2 h, on 4 different occasions, at least two weeks apart, in a randomized, crossover study. Blood was obtained before exposures (baseline), 1 h after and 20 h after exposures. Plasma HDL anti-oxidant/anti-inflammatory capacity and paraoxonase activity were determined. HDL anti-oxidant/anti-inflammatory capacity was assessed by a cell-free fluorescent assay and expressed in units of a HDL oxidant index (HOI). Changes in HOI (ΔHOI) were calculated as the difference in HOI from baseline to 1 h after or 20 h after exposures.
  
  
  
  There was a trend towards bigger ΔHOI between PM2.5 and FA 1 h after exposures (p = 0.18) but not 20 h after. This trend became significant (p <0.05) when baseline HOI was lower (<1.5 or <2.0), indicating decreased HDL anti-oxidant/anti-inflammatory capacity shortly after the exposures. There were no significant effects of ozone alone or in combination with PM2.5 on the change in HOI at both time points. The change in HOI due to PM2.5 showed a positive trend with particle mass concentration (p = 0.078) and significantly associated with the slope of systolic blood pressure during exposures (p = 0.005).
  
  
  
  Brief exposures to concentrated PM2.5 elicited swift effects on HDL anti-oxidant/anti-inflammatory functionality, which could indicate a potential mechanism for how particulate air pollution induces harmful cardiovascular effects.
authors.affiliation: Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, 10833 Le Conte Avenue, CHS 43-264, P.O. Box 951679, Los Angeles, CA, 90095, USA.
authors.forename: Gajalakshmi
authors.initials: G
authors.lastname: Ramanathan
authors.affiliation: Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, 10833 Le Conte Avenue, CHS 43-264, P.O. Box 951679, Los Angeles, CA, 90095, USA.
authors.forename: Fen
authors.initials: F
authors.lastname: Yin
authors.affiliation: Division of Occupational and Environmental Health, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada.
authors.forename: Mary
authors.initials: M
authors.lastname: Speck
authors.affiliation: Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, 10833 Le Conte Avenue, CHS 43-264, P.O. Box 951679, Los Angeles, CA, 90095, USA.
authors.forename: Chi-Hong
authors.initials: CH
authors.lastname: Tseng
authors.affiliation: Environment Canada, Toronto, ON, Canada.|Southern Ontario Centre for Atmospheric Aerosol Research (SOCAAR), Toronto, ON, Canada.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Brook
authors.affiliation: Southern Ontario Centre for Atmospheric Aerosol Research (SOCAAR), Toronto, ON, Canada.|Division of Occupational and Environmental Health, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada.|Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.|Li Ka Shing Knowledge Institute, St Michael's Hospital, Toronto, ON, Canada.
authors.forename: Frances
authors.initials: F
authors.lastname: Silverman
authors.affiliation: Southern Ontario Centre for Atmospheric Aerosol Research (SOCAAR), Toronto, ON, Canada.|Division of Occupational and Environmental Health, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada.|Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
authors.forename: Bruce
authors.initials: B
authors.lastname: Urch
authors.affiliation: Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Brook
authors.affiliation: Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, 10833 Le Conte Avenue, CHS 43-264, P.O. Box 951679, Los Angeles, CA, 90095, USA. JAraujo@mednet.ucla.edu.|Department of Environmental Health Sciences, Fielding School of Public Health, University of California, Los Angeles, USA. JAraujo@mednet.ucla.edu.|Molecular Biology Institute, University of California, Los Angeles, CA, USA. JAraujo@mednet.ucla.edu.
authors.forename: Jesus A
authors.initials: JA
authors.lastname: Araujo
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000737:chemistry / Q000633:toxicity; D000397:Air Pollution / Q000009:adverse effects*; D015415:Biomarkers / Q000097:blood; D002318:Cardiovascular Diseases / Q000097:blood / Q000453:epidemiology / Q000209:etiology* / Q000276:immunology; D015331:Cohort Studies; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D019570:Inhalation Exposure / Q000009:adverse effects; D008075:Lipoproteins, HDL / Q000097:blood*; D008297:Male; D008954:Models, Biological; D016877:Oxidants / Q000737:chemistry / Q000633:toxicity; D018384:Oxidative Stress / Q000187:drug effects; D010126:Ozone / Q000633:toxicity*; D010316:Particle Size; D052638:Particulate Matter / Q000737:chemistry / Q000633:toxicity*; D012306:Risk; D016037:Single-Blind Method; D014504:Urban Health; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D015415:Biomarkers; D008075:Lipoproteins, HDL; D016877:Oxidants; D052638:Particulate Matter; D010126:Ozone
keywords: Air pollution; Cardiovascular; Fine particulate matter; HDL function; HDL oxidant index (HOI); High density lipoprotein (HDL); Ozone