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Completed

NCT Number: NCT01699204

Diesel Exhaust and Mechanism of Asthma

This experiment is designed to test the hypothesis that oxidative stress is responsible for changes in airway responsiveness in humans exposed to diesel exhaust.

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Key information

Conditions

Asthma Bronchial Diseases Hypersensitivity Hypersensitivity, Immediate Immune System Diseases Lung Diseases Lung Diseases, Obstructive Respiratory Hypersensitivity Respiratory Tract Diseases

Age range

19 year–49 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of British Columbia

Vancouver, British Columbia, V5Z1M9, Canada

About this study

The specific aim is to test the hypothesis that diesel exhaust (DE) increases airway reactivity via oxidative stress, particularly in asthmatics. To test this hypothesis, we use a crossover in vivo experimental model in mild asthmatics and normal controls using a state-of-the-art diesel exhaust exposure facility.

Participants took N-acetylcysteine (600 mg) or placebo capsules three times daily for six days. On the final morning of supplementation, participants were exposed for 2 hours to either filtered air or diesel exhaust (300 µg·m-3 of particulate matter smaller than 2.5 microns). Twenty-six non-smokers between 19-49 years were studied under three experimental conditions (filtered air with placebo, diesel exhaust with placebo and diesel exhaust with N-acetylcysteine) using randomized, double-blind, crossover design, with a two week minimum washout between conditions. Methacholine challenge was performed pre-exposure (to determine baseline airway responsiveness) and post-exposure (to determine the effect of exposure).

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Between 19-49 years, non smokers, asthmatics, healthy controls

Exclusion criteria

  • Smokers, pregnant or co-existing medical condition for which diesel exhaust would confer significant risk (i.e. coronary artery disease)

Treatment and study plan

N-acetylcysteine

Dietary Supplement

N-acetylcysteine 600mg taken orally 3 times daily for 6 days prior to exposure to diesel exhaust for 2 hours. The last supplement was taken the morning of the exposure

Diesel Exhaust

Other

A placebo tablet taken 3 times daily for 6 days prior to exposure to diesel exhaust for 2 hours. The last supplement was taken the morning of the exposure

Filtered Air

Other

A placebo tablet taken 3 times daily for 6 days prior to exposure to filtered air for 2 hours. The last supplement was taken the morning of the exposure

Primary outcomes

  1. Human airway reactivity

    Time frame: 50 hours

    Establish that oxidative stress is responsible for changes in human airway reactivity induced by DE (300 µg/m3 inhaled for two hours).

Sponsors and collaborators

Lead sponsor

University of British Columbia

Other

Registry information

Official study title

Effects of Diesel Exhaust on Airways

Important dates

Study start
2007
Primary completion
2011
Study completion
2011
First posted
Oct 3, 2012
Registry last updated
Sep 29, 2017

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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