Human Biological Responses to Low Level Ozone (SNOZ)
|The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details.|
|ClinicalTrials.gov Identifier: NCT02857283|
Recruitment Status : Recruiting
First Posted : August 5, 2016
Last Update Posted : October 5, 2018
|Condition or disease||Intervention/treatment||Phase|
|Environmental Exposure Nasal Inflammation||Other: Ozone Other: Filtered Air||Not Applicable|
Air pollutants including ozone have been implicated in affecting health outcomes. In particular, high level ozone exposure has been shown to affect pulmonary function and cause pulmonary inflammation. Troubling community-based work has implicated high ozone levels as being correlated with increased pediatric asthma ED visits. Because of adverse health effects, EPA standards for safe ozone levels have been set, currently at 0.07 ppm. Still, it is estimated that 100 million Americans live in areas where ozone levels periodically remain above the EPA standard. And while this EPA standard had been set based on available data, it remained unclear at the time whether naturalistic low-level ozone exposure, such as fluctuations between 0.06-0.08 ppm throughout the day, might affect health as well.
This group previously examined lung function and inflammatory response in adults exposed to low-level ozone, 0.06 ppm exposure for 6.6 hours, while undergoing intermittent moderate exercise. The investigators found that in response to low-level ozone exposure (0.06 ppm) with exercise, lung function declines and neutrophilic airway inflammation is observed. What remains unclear, is whether low-level ozone alone - without exercise - will cause similar health effects.
To mimic exposure to ozone on a typical summer day in a polluted city, the investigators will expose subjects to a varying level of ozone, form 0.06 ppm to 0.08 ppm, rather than a constant 0.07ppm. The variation from 0.06ppm to 0.08ppm, then back to 0.06ppm will occur each hour.
|Study Type :||Interventional (Clinical Trial)|
|Estimated Enrollment :||16 participants|
|Intervention Model:||Crossover Assignment|
|Masking:||Double (Participant, Investigator)|
|Primary Purpose:||Basic Science|
|Official Title:||Human Biological Responses to Low Level Ozone|
|Actual Study Start Date :||February 22, 2017|
|Estimated Primary Completion Date :||July 2019|
|Estimated Study Completion Date :||July 2019|
Placebo Comparator: Filtered Air
filtered clean air
Other: Filtered Air
Subject will be exposed to filtered clean air
Active Comparator: Ozone
The ozone concentration will be varied from 0.06 to 0.08
Subject will be exposed to a concentration of ozone for 6.5 hours
- Change in % Polymorphonuclear Leukocyte (PMN) in nasal lavage fluid [ Time Frame: Baseline, immediately post-exposure, and 24 hours post-exposure ]Participants will be exposed to either filtered air (FA) or ozone (O3). Nasal lavage fluid will be collected from participants at baseline prior to exposure (within six weeks), immediately after exiting the exposure chamber, and again at 24 hours after the exposure. The change in nasal PMN counts from baseline to immediately post- and 24 hours post-exposure will be measured and compared between FA and O3.
- Nasal epithelial cell gene expression [ Time Frame: Baseline and immediately post-exposure ]RNA isolated from nasal epithelial cell biopsies collected at baseline prior to exposure (within six weeks) and immediately after exposure to either FA or O3 will be analyzed via qRT-PCR to determine the impact of O3 on inflammatory gene expression.
- Change in Nasal Immune mediators of cytokines [ Time Frame: Baseline, immediately post-exposure, and 24 hours post-exposure ]Protein detection assays, such as ELISAs, will be used to quantitate the amount of immune mediators present in the nasal passage. Nasal lavage fluid and epithelial lining fluid will be collected from participants at baseline prior to exposure (within six weeks), immediately after exiting the exposure chamber, and again at 24 hours after the exposure. The difference between the amount of protein will be calculated to determine the effect of ozone on the production of nasal immune mediators.
- Change in sputum cell counts [ Time Frame: Baseline and 24 hours post-exposure ]Participants will undergo a hypertonic saline induced sputum procedure at baseline prior to exposure (within six weeks) to either FA or O3, and again at 24 hours following the exposure. Sputum will be assessed for cellularity.
- Change in FEV1 [ Time Frame: Baseline, immediately post-exposure, and 24 hours post-exposure ]Lung function of participants will be assessed via spirometry at baseline prior to exposure (within six weeks), immediately after exposure to either FA or O3, and again at 24 hours after the exposure to examine the impact of O3 on lung function.
- Change in Flow mediated dilation [ Time Frame: Baseline and immediately post-exposure ]Participants will undergo flow-mediated brachial artery dilation at baseline prior to exposure (within six weeks), and immediately after exposure to either FA or O3 to assess the impact of O3 exposure on endothelial function.
- Change in left ventricular contractility [ Time Frame: Baseline and immediately post-exposure ]Left ventricular mechanics will be assessed at baseline prior to exposure (within six weeks), and immediately after the exposure by measuring global longitudinal strain using speckle tracking echocardiography. The change in global longitudinal strain will be calculated to determine the effect of ozone on left ventricular contractility.
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02857283
|Contact: Sally Ivinsfirstname.lastname@example.org|
|United States, North Carolina|
|Center for Environmental Medicine, Asthma and Lung Biology||Recruiting|
|Chapel Hill, North Carolina, United States, 27599|
|Principal Investigator:||David B Peden, MD||University of North Carolina, Chapel Hill|