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Diesel Exhaust Induces Glucocorticoid Resistance (DIGR)

Primary Purpose

Exposure to Pollution, Glucocorticoid Resistance

Status
Recruiting
Phase
Phase 4
Locations
Canada
Study Type
Interventional
Intervention
Placebo
Budesonide
Filtered Air
Diesel Exhaust
Sponsored by
University of British Columbia
About
Eligibility
Locations
Arms
Outcomes
Full info

About this trial

This is an interventional prevention trial for Exposure to Pollution focused on measuring Diesel Exhaust, Air Pollution, Inhaled Corticosteroids, Gene Expression, Asthma, Controlled Human Exposure Study

Eligibility Criteria

19 Years - 49 Years (Adult)All SexesDoes not accept healthy volunteers

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

Sites / Locations

  • University of British ColumbiaRecruiting

Arms of the Study

Arm 1

Arm 2

Arm 3

Arm 4

Arm Type

Placebo Comparator

Active Comparator

Active Comparator

Experimental

Arm Label

Placebo and Filtered Air

Budesonide and Filtered Air

Placebo and Diesel Exhaust

Budesonide and Diesel Exhaust

Arm Description

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.

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

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.

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.

Outcomes

Primary Outcome Measures

Change in DNA methylation, mRNA and protein expression attributable to diesel exhaust and inhaled corticosteroid
EPIC arrays and RNA Seq will be used to determine effect of exposure(s)

Secondary Outcome Measures

Modification by variants in genes governing inflammation and responses to oxidative stress after DE exposure and ICS.
genotypes will be assessed by polymerase chain reaction assay (PCR) and a gene score created for statistical interaction analysis

Full Information

First Posted
July 23, 2018
Last Updated
November 10, 2022
Sponsor
University of British Columbia
Collaborators
Canadian Institutes of Health Research (CIHR), AllerGen NCE Inc.
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1. Study Identification

Unique Protocol Identification Number
NCT03615742
Brief Title
Diesel Exhaust Induces Glucocorticoid Resistance
Acronym
DIGR
Official Title
Diesel Exhaust Induces Glucocorticoid Resistance
Study Type
Interventional

2. Study Status

Record Verification Date
November 2022
Overall Recruitment Status
Recruiting
Study Start Date
December 1, 2018 (Actual)
Primary Completion Date
December 31, 2023 (Anticipated)
Study Completion Date
December 31, 2025 (Anticipated)

3. Sponsor/Collaborators

Responsible Party, by Official Title
Principal Investigator
Name of the Sponsor
University of British Columbia
Collaborators
Canadian Institutes of Health Research (CIHR), AllerGen NCE Inc.

4. Oversight

Studies a U.S. FDA-regulated Drug Product
No
Studies a U.S. FDA-regulated Device Product
No
Product Manufactured in and Exported from the U.S.
No
Data Monitoring Committee
No

5. Study Description

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.
Detailed Description
1) Purpose Inhalation of air pollutants leads to both airway inflammation, with increased cytokine expression and inflammatory cell recruitment to the airways, and to airway hyperresponsiveness, which together contribute to airway resistance and breathing difficulties. Correlational data indicate that exposure to air pollution increases inhaled corticosteroids (ICS) use in asthmatics, suggesting that steroidal anti-inflammatory medications are suboptimally effective under these conditions. However, a major issue is that no study has yet been performed specifically to determine the effects of controlled diesel exhaust (DE) exposure on responses to ICS. Furthermore, investigators need better insight into mechanisms, including the effects of epigenetic modifications and polymorphisms in oxidative stress response genes, which remain under explored. Investigators anticipate that an improved understanding of air pollution-induced ICS hyporesponsiveness (reduced effectiveness) could underpin preventative guidelines, guide ICS usage in response to environmental exposures, and inform rational pharmaceutical development. Ultimately this could lead to fewer exacerbations in asthmatic and other susceptible populations. Hypothesis: Acute exposure to DE reduces ICS-inducible gene expression in vivo in asthmatics, in part through effects on epigenetic processes. Justification: Air pollution exposure correlates with increased use of ICS inhalers in asthmatics, suggesting that ICS offer less control during periods of higher air pollution. As genes induced by ICS are critical in reducing inflammatory messenger ribonucleic acid (mRNA) and protein expression, the investigators have chosen to focus on the effects of DE on ICS-inducible gene expression as our primary endpoint. Research Method: To test this the effects of air pollution exposure on a corticosteroid, volunteers will inhale either a placebo (inhaler containing no medication) or budesonide (1.6mg), before sitting in our exposure booth for 2 hours breathing either filtered air (as a control) or diluted diesel exhaust (standardized to 300µg/m³ of particulate matter with a diameter of 2.5 micrometers or less). Volunteers will visit our lab four different times to be exposed to: 1) placebo & filtered air, 2) placebo & diesel exhaust, 3) corticosteroid and filtered air, and 4) corticosteroid and diesel exhaust. Investigators can then compare responses to each of these combinations of exposures. Investigators will take blood samples before and after volunteers complete each of these exposures to track how they affect the body. Six hours after placebo or budesonide inhalation a research bronchoscopy will be performed during which a very thin flexible tube will be inserted through the mouth and down into lungs to collect samples from each volunteer. Bronchoalveolar lavage, bronchial washes, bronchial brushes and tissue biopsies will be obtained for analysis of gene expression and epigenetic endpoints. 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 will be used to assess effects on airway function.

6. Conditions and Keywords

Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Exposure to Pollution, Glucocorticoid Resistance
Keywords
Diesel Exhaust, Air Pollution, Inhaled Corticosteroids, Gene Expression, Asthma, Controlled Human Exposure Study

7. Study Design

Primary Purpose
Prevention
Study Phase
Phase 4
Interventional Study Model
Crossover Assignment
Model Description
Volunteers will visit our lab four different times to be exposed to: 1) placebo & filtered air, 2) placebo & diesel exhaust, 3) budesonide and filtered air, and 4) budesonide and diesel exhaust
Masking
ParticipantInvestigatorOutcomes Assessor
Masking Description
Blinding of exposures will be performed by the air pollution exposure laboratory (APEL) engineer, who will not interact with volunteers. Visually indistinguishable placebo and budesonide inhalers will be coded by research pharmacy staff. All assays will be performed by personnel who do not know the exposure conditions of individual samples.
Allocation
Randomized
Enrollment
30 (Anticipated)

8. Arms, Groups, and Interventions

Arm Title
Placebo and Filtered Air
Arm Type
Placebo Comparator
Arm Description
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.
Arm Title
Budesonide and Filtered Air
Arm Type
Active Comparator
Arm Description
Volunteers will inhale 1.6mg of budesonide before sitting in a booth and being exposed to HEPA filtered air for 2 hours.
Arm Title
Placebo and Diesel Exhaust
Arm Type
Active Comparator
Arm Description
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.
Arm Title
Budesonide and Diesel Exhaust
Arm Type
Experimental
Arm Description
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.
Intervention Type
Other
Intervention Name(s)
Placebo
Intervention Description
Inhalation of air through a Turbuhaler that contains no medication, as a control.
Intervention Type
Drug
Intervention Name(s)
Budesonide
Other Intervention Name(s)
Pulmicort
Intervention Description
1.6mg of budesonide from a Turbuhaler.
Intervention Type
Other
Intervention Name(s)
Filtered Air
Intervention Description
Exposure to HEPA filtered air, as a control.
Intervention Type
Other
Intervention Name(s)
Diesel Exhaust
Other Intervention Name(s)
Traffic Related Air Pollution
Intervention Description
Diesel exhaust standardized to 300µg/m³ of particulate matter with a diameter of 2.5 micrometers or less (PM2.5).
Primary Outcome Measure Information:
Title
Change in DNA methylation, mRNA and protein expression attributable to diesel exhaust and inhaled corticosteroid
Description
EPIC arrays and RNA Seq will be used to determine effect of exposure(s)
Time Frame
Baseline versus 6 hours
Secondary Outcome Measure Information:
Title
Modification by variants in genes governing inflammation and responses to oxidative stress after DE exposure and ICS.
Description
genotypes will be assessed by polymerase chain reaction assay (PCR) and a gene score created for statistical interaction analysis
Time Frame
Baseline versus 6 hours

10. Eligibility

Sex
All
Minimum Age & Unit of Time
19 Years
Maximum Age & Unit of Time
49 Years
Accepts Healthy Volunteers
No
Eligibility Criteria
Inclusion Criteria: Aged 19-49 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: Smoking of any kind (0.5 pack-years ever, or any current) or use of vape/vaporizing devices Regular anti-histamine, NSAID, corticosteroid or other controller medication use Pregnancy or breastfeeding Methacholine PC20 >16 Relevant cardiac condition or arrhythmia Body mass index of >35 Currently participating in another study that may interfere with this study Use of either inhaled or oral corticosteroids in preceding 6 months Substantial comorbidities on study physician's examination or other concerns Surgery scheduled before anticipated study completion
Central Contact Person:
First Name & Middle Initial & Last Name or Official Title & Degree
Ryan D Huff, MSc
Phone
6048755132
Email
rhuff@mail.ubc.ca
First Name & Middle Initial & Last Name or Official Title & Degree
Agnes CY Yuen, BSc
Phone
6048754111
Ext
66455
Email
agnes.yuen@ubc.ca
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
Chris Carlsten, MD
Organizational Affiliation
University of British Columbia
Official's Role
Principal Investigator
First Name & Middle Initial & Last Name & Degree
Christopher F Rider, PhD
Organizational Affiliation
University of British Columbia
Official's Role
Study Director
First Name & Middle Initial & Last Name & Degree
Robert Newton, PhD
Organizational Affiliation
University of Calgary
Official's Role
Study Director
Facility Information:
Facility Name
University of British Columbia
City
Vancouver
State/Province
British Columbia
ZIP/Postal Code
V5Z1M9
Country
Canada
Individual Site Status
Recruiting
Facility Contact:
First Name & Middle Initial & Last Name & Degree
Chris Carlsten, MD MPH
Phone
604-875-4729
Email
carlsten@mail.ubc.ca
First Name & Middle Initial & Last Name & Degree
Ryan D Huff, MSc
Phone
604-875-5132
Email
digr.study@ubc.ca
First Name & Middle Initial & Last Name & Degree
Christopher F Rider, PhD
First Name & Middle Initial & Last Name & Degree
Robert Newton, PhD

12. IPD Sharing Statement

Plan to Share IPD
No

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Diesel Exhaust Induces Glucocorticoid Resistance

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