Air Pollution and Allergens - Attenuation of Health Effects Particle Reduction
NCT ID: NCT02017431
Last Updated: 2017-09-29
Study Results
The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.
Basic Information
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COMPLETED
NA
13 participants
INTERVENTIONAL
2014-01-31
2017-04-30
Brief Summary
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Detailed Description
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The aim of this study is to investigate the ability of depletion of diesel exhaust particles to attenuate adverse effects of diesel exhaust on lung function and on allergic responses.
2. Hypotheses:
Hypothesis 1: Allergen-specific immune response (specific IgG4, etc; relevant responses in DNA methylation and proteomics) in allergen-challenged airways in sensitized individuals is increased by diesel exhaust "synergy".
Hypothesis 2: Synergistic responses will be greater in asthmatics than in non-asthmatics.
Hypotheses 3: Synergy is attributable to the particulate fraction of DE (i.e. is normalized by particle depletion).
3. Justification:
Diesel exhaust consists of both gaseous and particulate air pollutants. In recent studies, cardiovascular effects seem attenuated when the particulate portion is removed. We would like to know if that is true for respiratory and immunological endpoints. Understanding these changes may help us prevent health problems associated with air pollution in the future.
4. Research Method:
Blinded crossover experiment between four conditions (DE and allergen, PDDE and allergen, FA and allergen, FA and saline), randomized and counter-balanced to order. Each condition will be separated by a 4-week washout period.
An inhaled allergen or saline challenge is delivered after each exposure (DE, PDDE, or FA). 24 h post challenge, airway reactivity will be assessed with a methacholine challenge. 48 h post challenge, bronchoalveolar lavage (BAL), airway brushes and tissue biopsies will be obtained 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.
Conditions
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Study Design
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RANDOMIZED
CROSSOVER
BASIC_SCIENCE
TRIPLE
Study Groups
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Filtered air
Exposure for 2 hours to filtered air followed by subject specific inhaled allergen challenge
Allergen
Subject specific allergen is inhaled on day 1 of the triad
Diesel exhaust
Exposure for 2 hours to diesel exhaust followed by subject specific inhaled allergen challenge
Allergen
Subject specific allergen is inhaled on day 1 of the triad
Filtered air control
Exposure for 2 hours to filtered air followed by inhaled saline challenge
Saline
Saline is inhaled on day 1 of the triad
Particle depleted diesel exhaust
Exposure for 2 hours to particle depletion diesel exhaust followed by inhaled allergen challenge
Allergen
Subject specific allergen is inhaled on day 1 of the triad
Particle depleted diesel exhaust
High-efficiency particulate filtration of diesel exhaust
Interventions
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Allergen
Subject specific allergen is inhaled on day 1 of the triad
Saline
Saline is inhaled on day 1 of the triad
Particle depleted diesel exhaust
High-efficiency particulate filtration of diesel exhaust
Eligibility Criteria
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Inclusion Criteria
* Non-smoking
* Positive skin prick test for at least one of: birch, grass, or dust
Exclusion Criteria
* Pregnant or planning to be pregnant in the next 12 months / Breastfeeding
* Usage of bronchodilators more than three times per week.
* Co-morbidities (as assessed by the primary investigator)
* Taking part in other studies
* Unwilling to withhold bronchodilator, aspirin, anti-coagulant, antihistamine or decongestant medications or caffeine prior to testing procedures.
* FEV1(Forced expiratory volume in one second) \< 70% predicted.
* Allergy to lidocaine, fentanyl, midazolam or salbutamol.
* Unstable asthma (i.e exacerbation in 2 weeks preceding testing)
19 Years
49 Years
ALL
Yes
Sponsors
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University of British Columbia
OTHER
Responsible Party
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Christopher Carlsten
Principal Investigator
Principal Investigators
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Christopher Carlsten, MD, MPH
Role: PRINCIPAL_INVESTIGATOR
University of British Columbia
Locations
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University of British Columbia
Vancouver, British Columbia, Canada
Countries
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References
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Calhoun WJ, Jarjour NN, Gleich GJ, Stevens CA, Busse WW. Increased airway inflammation with segmental versus aerosol antigen challenge. Am Rev Respir Dis. 1993 Jun;147(6 Pt 1):1465-71. doi: 10.1164/ajrccm/147.6_Pt_1.1465.
Diaz-Sanchez D, Dotson AR, Takenaka H, Saxon A. Diesel exhaust particles induce local IgE production in vivo and alter the pattern of IgE messenger RNA isoforms. J Clin Invest. 1994 Oct;94(4):1417-25. doi: 10.1172/JCI117478.
Nordenhall C, Pourazar J, Ledin MC, Levin JO, Sandstrom T, Adelroth E. Diesel exhaust enhances airway responsiveness in asthmatic subjects. Eur Respir J. 2001 May;17(5):909-15. doi: 10.1183/09031936.01.17509090.
Carlsten C, Melen E. Air pollution, genetics, and allergy: an update. Curr Opin Allergy Clin Immunol. 2012 Oct;12(5):455-60. doi: 10.1097/ACI.0b013e328357cc55.
Riedl MA, Diaz-Sanchez D, Linn WS, Gong H Jr, Clark KW, Effros RM, Miller JW, Cocker DR, Berhane KT; HEI Health Review Committee. Allergic inflammation in the human lower respiratory tract affected by exposure to diesel exhaust. Res Rep Health Eff Inst. 2012 Feb;(165):5-43; discussion 45-64.
Robinson A, Huff RD, Ryu MH, Carlsten C. Variants in transient receptor potential channels and toll-like receptors modify airway responses to allergen and air pollution: a randomized controlled response human exposure study. Respir Res. 2023 Sep 7;24(1):218. doi: 10.1186/s12931-023-02518-y.
Ryu MH, Lau KS, Wooding DJ, Fan S, Sin DD, Carlsten C. Particle depletion of diesel exhaust restores allergen-induced lung-protective surfactant protein D in human lungs. Thorax. 2020 Aug;75(8):640-647. doi: 10.1136/thoraxjnl-2020-214561. Epub 2020 May 28.
Wooding DJ, Ryu MH, Huls A, Lee AD, Lin DTS, Rider CF, Yuen ACY, Carlsten C. Particle Depletion Does Not Remediate Acute Effects of Traffic-related Air Pollution and Allergen. A Randomized, Double-Blind Crossover Study. Am J Respir Crit Care Med. 2019 Sep 1;200(5):565-574. doi: 10.1164/rccm.201809-1657OC.
Other Identifiers
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H11-01831/2013
Identifier Type: -
Identifier Source: org_study_id