Recruiting

Glucocorticoid Resistance

Sponsor:

University of British Columbia

Code:

NCT03615742

Conditions

Exposure to Pollution

Glucocorticoid Resistance

Eligibility Criteria

Sex: All

Age: 19 - 49

Healthy Volunteers: Not accepted

Interventions

Placebo

Budesonide

Filtered Air

Diesel Exhaust

Study Details

Brief summary:

The investigators are studying the effects of exposure to diesel exhaust on lung inflammation in the presence and absence of an inhaled corticosteroid. Although data is mixed, studies show that asthmatics have increased lung inflammation and worse symptoms during periods of higher air pollution despite taking their anti-inflammatory corticosteroid medication. One possible reason is that air pollution exposure may decrease the ability of corticosteroids to combat inflammation.

To test this volunteers will inhale either a placebo or a corticosteroid, before sitting in an exposure booth for 2 hours breathing either filtered air or diluted diesel exhaust. Samples will be collected before and after exposure to analyze the effects of budesonide and diesel exhaust exposure.

Conditions

Exposure to Pollution

Glucocorticoid Resistance

Study ID

NCT03615742

Start date

Dec 1, 2018

Status verified date

Jul, 2024

Completion date

Dec 31, 2025

Anticipated

Primary completion date

Dec 31, 2025

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 19 - 49

Healthy Volunteers: Not accepted

Inclusion Criteria:

1. Aged 19-49
2. Have physician-diagnosed asthma confirmed by the study physician examination, spirometry, methacholine challenge provocative concentration causing a 20% fall (PC20) of <16 mg/mL, and questionnaires during a screening visit

Exclusion Criteria:

1. Smoking of any kind (0.5 pack-years ever, or any current) or use of vape/vaporizing devices
2. Regular anti-histamine, NSAID, corticosteroid or other controller medication use
3. Pregnancy or breastfeeding
4. Methacholine PC20 >16
5. Relevant cardiac condition or arrhythmia
6. Body mass index of >35
7. Currently participating in another study that may interfere with this study
8. Use of either inhaled or oral corticosteroids in preceding 6 months
9. Substantial comorbidities on study physician's examination or other concerns
10. Surgery scheduled before anticipated study completion

Study Design

Enrollment

30 participants

Anticipated

Allocation

Randomized

Intervention Model

Crossover

Primary purpose

Prevention

Interventions and Outcome Measures

Arms

placebo comparator: Placebo and Filtered Air

Volunteers will use an inhaler that does not contain any medication, before sitting in a booth and being exposed to high-efficiency particulate air (HEPA) filtered air for 2 hours.

active comparator: Budesonide and Filtered Air

Volunteers will inhale 1.6mg of budesonide before sitting in a booth and being exposed to HEPA filtered air for 2 hours.

active comparator: Placebo and Diesel Exhaust

Volunteers will use an inhaler that does not contain any medication, before sitting in a booth and being exposed to 300µg/m³ concentration of diesel exhaust for 2 hours.

experimental: Budesonide and Diesel Exhaust

Volunteers will inhale 1.6mg of budesonide before sitting in a booth and being exposed to 300µg/m³ concentration of diesel exhaust for 2 hours.

Interventions

Placebo

Inhalation of air through a Turbuhaler that contains no medication, as a control.

Budesonide

1.6mg of budesonide from a Turbuhaler.

Filtered Air

Exposure to HEPA filtered air, as a control.

Diesel Exhaust

Diesel exhaust standardized to 300µg/m³ of particulate matter with a diameter of 2.5 micrometers or less (PM2.5).

Primary outcome measure

  • Change in DNA methylation, mRNA and protein expression attributable to diesel exhaust and inhaled corticosteroid [ Time Frame: Baseline versus 6 hours ]

Central Contacts and Locations

Central contacts

Parteek (PJ) Johal, BCS

6048755132de.study@ubc.ca

Agnes CY Yuen, BSc

6048754111agnes.yuen@ubc.ca

Locations

University of British Columbia

Recruiting

Vancouver, British Columbia, Canada, V5Z1M9

Contacts

Chris Carlsten, MD MPH

604-875-4729carlsten@mail.ubc.ca

Ryan D Huff, MSc

604-875-5132digr.study@ubc.ca

More Information

Sponsor

University of British Columbia

Last update posted

Jul 24, 2024

Last verified

Jul, 2024

Keywords

  • Diesel Exhaust
  • Air Pollution
  • Inhaled Corticosteroids
  • Gene Expression
  • Asthma
  • Controlled Human Exposure Study

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by University of British Columbia on 2024-07-24.