Effects of Co-Exposure to Air Pollution and Allergen

September 27, 2017 updated by: Christopher Carlsten, University of British Columbia

Effect of Exposure to Allergens and Air Pollution on Lung Function and Immunity

The investigators are investigating the effects of combined exposures to diesel exhaust and allergens on lung function and on the immune system. After exposing individuals to either filtered air or carefully controlled levels of diesel exhaust in our exposure chamber, The investigators will use a procedure called bronchoscopy (whereby a thin, flexible tube is passed down the throat and into the lungs) to place a small amount of allergen directly in the lung. 48h later, the bronchoscopy will be repeated so that samples can be collected from the lungs. After 1mo, the entire procedure will be repeated with the alternate exposure.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

  1. Purpose/Objective:

    To study the effects of diesel exhaust particles on lung function and on allergic responses.

  2. Hypotheses:

    Hypothesis 1: DE exposure augments systemic oxidative stress from allergen challenge in allergen-sensitized individuals.

    Hypothesis 2: DE exposure augments allergen-specific immune response in allergen-challenged airways in sensitized individuals. These responses will be greater in asthmatic individuals than in non-asthmatics.

  3. Justification:

    The use of diesel engines is increasing because they are more fuel-efficient than gasoline engines. However, diesel engines produce different emissions than gasoline engines. Diesel exhaust is emitted from the tailpipe of both "on-road" diesel engine vehicles (diesel cars, buses and trucks) and "non-road" diesel engines (locomotives, marine vessels and some construction equipment). Diesel exhaust consists of both gaseous and particulate air pollutants. Since people with asthma and allergic diseases appear to be sensitive to air pollution, we would like to know how diesel exhaust (DE) can affects your respiratory and immune systems. We are expecting that any responses that may occur will only be detectable through careful examination of cells and tissues (e.g., bronchoalveolar lavage (fluid from your lungs), blood, urine). Understanding these potentially subtle changes will help us prevent health problems associated with air pollution in the future.

  4. Research Method:

This is a blinded crossover experiment between two conditions (DE or filtered air, FA), randomized and counter-balanced to order. Data collection for each condition will be separated by a 4-week washout period.

Following each exposure, The investigators will use bronchoscopy (performed at the Vancouver General Hospital Endoscopy Suite) to deliver a diluent-controlled segmental allergen challenge (SAC). 24 h post-SAC, airway reactivity will be assessed with a methacholine challenge. 48 h post-SAC, bronchoalveolar lavage (BAL), airway brushes and tissue biopsies will be obtained in the same regions for analysis of immune activation. Nasal lavage samples will also be collected to examine responses in the upper airways and blood and urine will be studied to examine systemic responses. Spirometry and methacholine challenge will be used to assess effects on airway function

Study Type

Interventional

Enrollment (Actual)

18

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • British Columbia
      • Vancouver, British Columbia, Canada, V5Z 1M9
        • University of British Columbia

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

19 years to 49 years (ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  1. Age between 19 and 49 years.
  2. Non-smoking.
  3. Positive skin prick test for at least one of: birch, grass, or dust

Exclusion Criteria:

  1. Using inhaled corticosteroids
  2. Pregnant or planning to be pregnant in the next 12 months / Breastfeeding
  3. Usage of bronchodilators more than three times per week.
  4. Co-morbidities (as assessed by the primary investigator)
  5. Taking part in other studies
  6. Unwilling to withhold bronchodilator, aspirin, anti-coagulant, antihistamine or decongestant medications or caffeine prior to testing procedures.
  7. FEV1(Forced expiratory volume in one second) < 70% predicted.
  8. Allergy to lidocaine, fentanyl, midazolam or salbutamol.
  9. Unstable asthma (i.e exacerbation in 2 weeks preceding testing)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: BASIC_SCIENCE
  • Allocation: RANDOMIZED
  • Interventional Model: CROSSOVER
  • Masking: TRIPLE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
ACTIVE_COMPARATOR: Filtered air
Exposure for 2 hours to filtered air followed by subject specific allergen placed in lung
Other: Allergen
Subject specific allergen is placed in the lungs on day 1 of each triad
EXPERIMENTAL: Diesel exhaust
Exposure for 2 hours to diesel exhaust followed by subject specific allergen placed in lung
Other: Allergen
Subject specific allergen is placed in the lungs on day 1 of each triad
ACTIVE_COMPARATOR: Filtered air control
Exposure for 2 hours to filtered air followed by subject saline placed in lung
Other: Saline
Saline will be placed in the lung on day 1 of each triad
ACTIVE_COMPARATOR: Diesel exhaust control
Exposure for 2 hours to diesel exhaust followed by saline placed in lung
Other: Saline
Saline will be placed in the lung on day 1 of each triad

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Allergen-specific IgE
Time Frame: 48 hours
BAL IgE specific to the allergen used for allergen challenge will be assessed at 48 hrs, from the BAL, using immunocap assay
48 hours

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Human immune response
Time Frame: 48 hours
Determine if allergen-induced eosinophilic activation (measured by flow cytometry) and a Th2-type cytokine pattern is augmented by DE (300 µg/m3 inhaled for two hours) exposure.
48 hours
Oxidative stress
Time Frame: 48 hours
Establish that bronchial segment allergen-induced oxidative stress (urine 8-isoprostane, measured by ELISA) is augmented by DE (300 µg/m3 inhaled for two hours) exposure.
48 hours
Airway reactivity
Time Frame: 48 hours
Determine if airway reactivity (measured by PC20 methacholine challenge) is augmented by DE (300 µg/m3 inhaled for two hours) exposure.
48 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of British Columbia

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

October 1, 2011

Primary Completion (ACTUAL)

November 1, 2013

Study Completion (ACTUAL)

November 1, 2013

Study Registration Dates

First Submitted

November 14, 2012

First Submitted That Met QC Criteria

February 12, 2013

First Posted (ESTIMATE)

February 15, 2013

Study Record Updates

Last Update Posted (ACTUAL)

September 29, 2017

Last Update Submitted That Met QC Criteria

September 27, 2017

Last Verified

September 1, 2017

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • H11-01831

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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