Effect of Diesel Exhaust Particulate Exposures on Endothelial Function in Humans

This study has been completed.
Sponsor:
Collaborator:
Information provided by (Responsible Party):
Joel Daniel Kaufman, University of Washington
ClinicalTrials.gov Identifier:
NCT00434005
First received: August 25, 2006
Last updated: January 14, 2013
Last verified: January 2013

August 25, 2006
January 14, 2013
July 2008
August 2010   (final data collection date for primary outcome measure)
Brachial artery caliber [ Time Frame: Pre-exposure, immediate post-exposure ] [ Designated as safety issue: No ]
  • Brachial Artery Reactivity
  • Glutathione
  • Ascorbate
  • Nitrate Nitrite
  • F2Isoprostanes
  • Heart Rate Variability
  • Flow Mediated Dilation
  • All measures taken before, during, and after each exposure
Complete list of historical versions of study NCT00434005 on ClinicalTrials.gov Archive Site
  • Brachial Artery Flow-Mediated Dilation [ Time Frame: Post-Exposure ] [ Designated as safety issue: No ]
  • Plasma Endothelin-1 [ Time Frame: Post-exposure (adjusted for pre-exposure level) ] [ Designated as safety issue: No ]
  • Serum IL-6 [ Time Frame: Post-exposure (adjusted for pre-exposure level) ] [ Designated as safety issue: No ]
Not Provided
Not Provided
Not Provided
 
Effect of Diesel Exhaust Particulate Exposures on Endothelial Function in Humans
Effect of Diesel Exhaust Particulate Exposures on Endothelial Function in Humans - the Role of Oxidative Stress

Objectives: This proposal addresses the overall hypothesis that ambient fine particulate matter exerts cardiovascular health effects via alteration of endothelial homeostasis, through a mechanism mediated by oxidative stress. This project will use a controlled human inhalation exposure to diesel exhaust particulate (DEP) as a model to address the following objectives: 1) Determine whether exposure to inhaled DEP is associated with endothelial dysfunction in a concentration-related manner; 2) Determine whether exposure to inhaled DEP is associated with evidence of systemic oxidative stress; and 3) Determine whether antioxidant supplementation blunts the DEP effect on endothelial function.

OBJECTIVES Evidence of the cardiovascular health effects of both acute and chronic exposure to ambient fine particulate matter (PM) has continued to accumulate in epidemiologic and experimental studies, without a demonstrated coherent pathophysiologic explanation. At the same time, the role of endothelial homeostasis in the development and triggering of cardiovascular disease has become more clear and compelling. Importantly, oxidative stress has emerged as a potential link between these two developments: Oxidative stress is known to play a role in endothelial dysfunction and is exerted by components of PM, especially of PM from combustion products. Based on this we propose an overall hypothesis: Inhalation of combustion-derived particles impact cardiovascular health by impairing endothelial function, through mechanisms mediated by increased oxidative stress.

Diesel exhaust particulate (DEP), an important contributor to ambient fine PM, has been demonstrated to exert oxidative stress in experimental systems. We propose a series of experiments to explore whether human exposure to DEP results in alteration of endothelial homeostasis and evidence of oxidative stress, and whether an antioxidant regimen can blunt the effects on endothelial function.

The objectives of this proposed research are to address the following specific hypotheses:

  1. Human exposure to inhaled DEP (at concentrations approximating 0, 100, 200 μg PM2.5/m3 [PM less than 2.5 microns in aerodynamic diameter]) results in concentration-related alteration of endothelial homeostasis, as reflected in ultrasonographic measurement of the brachial artery, plasma markers of endothelial homeostasis (endothelin-1, ICAM-1 [intercellular adhesion molecule-1], e-selectin, nitric oxide metabolites nitrate [NO3-] and nitrite [NO2-], IL-6, and TNF-α), and markers of thrombosis associated with endothelial activation or injury (plasminogen activator inhibitor-1 [PAI-1], Von Willebrand's factor [VWF], and D-dimer).
  2. Human exposure to inhaled DEP at 200 µg PM2.5/m3 results in evidence of systemic oxidative stress as assessed by markers in plasma and urine (isoprostane F-2α).
  3. Reduction in oxidant stress by ascorbate and N-acetylcysteine supplementation blunts the effect of inhaled DEP on endothelial function, as determined by ultrasonographic assessment of the brachial artery, plasma markers of endothelial homeostasis, or markers of thrombosis associated with endothelial activation.
Interventional
Not Provided
Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
Healthy
  • Drug: N-acetylcysteine, ascorbate
    NAC: 600mg twice daily for the day prior to exposure and 1x pre-exposure Ascorbate: 500mg twice daily for 7 days prior to exposure
  • Drug: Placebo
    matched appearance to acetylcysteine and ascorbate intervention
  • Experimental: Diesel Exhaust
    Interventions:
    • Drug: N-acetylcysteine, ascorbate
    • Drug: Placebo
  • Sham Comparator: Filtered Air
    Interventions:
    • Drug: N-acetylcysteine, ascorbate
    • Drug: Placebo
Cosselman KE, Krishnan RM, Oron AP, Jansen K, Peretz A, Sullivan JH, Larson TV, Kaufman JD. Blood pressure response to controlled diesel exhaust exposure in human subjects. Hypertension. 2012 May;59(5):943-8. doi: 10.1161/HYPERTENSIONAHA.111.186593. Epub 2012 Mar 19.

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Completed
24
August 2010
August 2010   (final data collection date for primary outcome measure)

Inclusion Criteria:

  • Healthy adults aged 18-49.

Exclusion Criteria:

  • Nonsmokers, no history of hypertension, asthma, diabetes, hypercholesterolemia, or other chronic conditions requiring ongoing medical care. No recent history of antioxidant, vitamin/mineral/botanical, or fatty acid supplementation beyond a daily multi-vitamin.
Both
18 Years to 49 Years
Yes
Contact information is only displayed when the study is recruiting subjects
United States
 
NCT00434005
22969-D, R830954, R827355, MO1RR-00037, ES015915, ES013195
No
Joel Daniel Kaufman, University of Washington
University of Washington
National Institutes of Health (NIH)
Principal Investigator: Joel D Kaufman, M.D., MPH University of Washington
University of Washington
January 2013

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP