Official Title: “The Cardiovascular Effects of Nitrogen Dioxide Exposure”

Exposure to air pollution has been linked to increased cardiorespiratory morbidity and mortality. The exact component of air pollution that mediates this effect is unknown, but the link is strongest for fine combustion derived particulate matter derived from traffic sources. It has been demonstrated that inhalation of diesel exhaust impairs vascular vasomotor tone and endogenous fibrinolysis. Recent studies using an inline retrofit particle trap to reduce the particulate component of exhaust have shown that filtering particles leads to a reversal of the endothelial dysfunction seen after diesel exhaust exposure, and have even suggested an augmentation of vascular function. This raises the question of the cardiovascular effects of the gaseous pollutants, the most abundant of which is nitrogen dioxide. In this study we plan to investigate the cardiovascular effects of nitrogen dioxide exposure.

Study Type: Interventional

Study Design: Basic Science, Randomized, Double Blind (Subject, Investigator, Outcomes Assessor), Crossover Assignment

Study Primary Completion Date: December 2008

Intervention(s) in this Clinical Trial

• Procedure: Forearm Vascular Study
  • Forearm venous occlusion plethysmography to measure forearm blood flow during intrabrachial infusion of vasodilators Acetylcholine (5-20 mg/min), sodium nitroprusside (2-8 µg/min), bradykinin (100-1000 pmol/min) and verapamil (10-100 µg/min)

Arms, Groups and Cohorts in this Clinical Trial

• Experimental: Air exposure
  • 1 hour exposure to filtered air during intermittent exercise
• Experimental: NO2 exposure
  • 1 hour exposure to nitrogen dioxide at 4ppm during intermittent exercise

Primary Measures

• Forearm blood flow measured by venous occlusion plethysmography in response to intraarterial vasodilators (acetylcholine, sodium nitroprusside, bradykinin and verapamil)
  • Time Frame: 4-6 hours after exposure
    Safety Issue?: No

Secondary Measures

• Plasma t-PA concentrations after infusion of bradykinin
  • Time Frame: During forearm study
    Safety Issue?: No
• Exhaled nitric oxide
  • Time Frame: 4-6 hours after exposure
    Safety Issue?: No

Inclusion Criteria:

• Healthy male volunteers

Exclusion Criteria:

• Current smokers
• Significant occupational exposure to air pollution
• Regular medication use
• Intercurrent illness

Gender Eligibility for this Clinical Trial: Male

Minimum Age for this Clinical Trial: N/A

Maximum Age for this Clinical Trial: N/A

Are Healthy Volunteers Accepted for this Clinical Trial?: Accepts Healthy Volunteers

Lead Sponsor: University of Edinburgh

Overall Clinical Trial Officials and Contacts

Thomas Sandström, MD PhD Principal Investigator Umeå University  

Information obtained from ClinicalTrials.gov on July 02, 2009

Link to the current ClinicalTrials.gov record. http://clinicaltrials.gov/show/NCT00774514

Study ID Number: Dnr 08-113M

ClinicalTrials.gov Identifier: NCT00774514

Health Authority: Sweden: Regional Ethical Review Board