The Cardiovascular Effects of Nitrogen Dioxide Exposure

Study Overview
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Brief Summary
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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.

Official Title
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The Cardiovascular Effects of Nitrogen Dioxide Exposure

Conditions
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Endothelial Dysfunction

Intervention / Treatment
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* Procedure: Forearm Vascular Study


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy male volunteers Exclusion Criteria: Current smokers Significant occupational exposure to air pollution Regular medication use Intercurrent illness
Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Air exposure<br>1 hour exposure to filtered air during intermittent exercise | Procedure: Forearm Vascular Study<br>* 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)<br>* Other names: BK;|
| Experimental: NO2 exposure<br>1 hour exposure to nitrogen dioxide at 4ppm during intermittent exercise | Procedure: Forearm Vascular Study<br>* 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)<br>* Other names: BK;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Forearm blood flow measured by venous occlusion plethysmography in response to intraarterial vasodilators (acetylcholine, sodium nitroprusside, bradykinin and verapamil) |  | 4-6 hours after exposure | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma t-PA concentrations after infusion of bradykinin |  | During forearm study | 
| Exhaled nitric oxide |  | 4-6 hours after exposure | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Air Pollution, Nitrogen Dioxide, NO2, Endothelial dysfunction