Environmental Exposure, Nasal Inflammation
Conditions
Keywords
Air pollution, Air pollutant exposure, Ozone
Brief summary
To investigate if low level ozone exposure will cause measurable inflammation in nasal cells.
Detailed description
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 emergency room 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.
Interventions
OTHEROzone
Participants will be exposed to a concentration of ozone for 6.5 hours at a concentration that varies 0.06 to 0.08
OTHERFiltered Air
Participants will be exposed to filtered clean air
DEVICEHealth and Exposure Tracker (HET)
Ozone and heart rate tracker
Sponsors
Environmental Protection Agency (EPA)
University of North Carolina, Chapel Hill
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
ALL
Age
18 Years to 50 Years
Healthy volunteers
Yes
Inclusion criteria
* Males and females between 18 and 50 years of age. * Vital signs within normal limits on admission to the study: Peripheral oxygen saturation (SpO2) \> 94%, systolic blood pressure between 150-90 mm Hg, diastolic blood pressure between 100-60 mm Hg, afebrile. * Forced Expiratory Volume (FEV1) of at least 80% of predicted.
Exclusion criteria
* Any chronic medical condition considered by the PI as a contraindication to the exposure study, including significant cardiovascular disease, diabetes requiring medication, chronic renal disease, chronic thyroid disease, or kidney disease. * Use of systemic or inhaled steroids. * Use of NSAID or aspirin within 7days of each study visit, and inability to withhold these medications prior to each session of the study. * Pregnant or nursing women * Use of cigarettes or other inhaled nicotine products within the past year, or more than a lifetime 5 pack year history of cigarette smoking.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in % Polymorphonuclear Leukocytes (PMN) in Nasal Lavage Fluid Immediately Post-Exposure From Baseline | Baseline, immediately post-exposure | Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Nasal lavage fluid (NLF) will be collected from participants at a baseline visit within two weeks prior to each exposure, and at the following time points for each exposure: immediately after exiting the exposure chamber, and at 24 hours after the exposure. The % PMN as a percentage of total inflammatory cells (total of monocytes and macrophages, PMN, eosinophils, basophils, lymphocytes, and bronchial epithelial cells) will be determined in each NLF collection by differential counts of cells on cytospin slides. The change in the values from baseline to immediately Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3. |
| Change in % Polymorphonuclear Leukocytes (PMN) in Nasal Lavage Fluid 24 Hours Post-Exposure From Baseline | Baseline, 24 hours post-exposure | Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Nasal lavage fluid (NLF) will be collected from participants at a baseline visit within two weeks prior to each exposure, and at the following time points for each exposure: immediately after exiting the exposure chamber, and at 24 hours after the exposure. The % PMN as a percentage of total inflammatory cells (total of monocytes and macrophages, PMN, eosinophils, basophils, lymphocytes, and bronchial epithelial cells) will be determined in each NLF collection by differential counts of cells on cytospin slides. The change in the values from baseline to 24 hours Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| The Percentage of Predicted Forced Expiratory Volume in One Second (% Predicted FEV1): Change Immediately Post-Exposure From Baseline | Baseline, immediately post-exposure | Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Standard spirometry to obtain FEV1 and forced vital capacity (FVC) measurements will be done at baseline within two weeks prior to first exposure, and immediately after exiting the exposure chamber for each exposure. The % Predicted FEV1 will be calculated from measured versus expected values. The change in % Predicted FEV1 from baseline to immediately Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3 to determine the effect of ozone on the % Predicted FEV1. |
| Interleukin-6 (IL-6) Concentrations in Nasal Epithelial Lining Fluid (ELF): Change 24 Hours Post-Exposure From Baseline | Baseline, 24 hours post-exposure | Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Nasal epithelial lining (ELF) will be collected from participants at baseline within two weeks prior to first exposure, and at the following time points for each exposure: immediately after exiting the exposure chamber, and at 24 hours after the exposure. The IL-6 concentration will be determined in each ELF sample by immunoassay. The change in IL-6 concentrations from baseline to 24 hours Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3 to determine the effect of ozone on the production of nasal IL-6. |
| Interleukin-8 (IL-8) Concentrations in Nasal Epithelial Lining Fluid (ELF): Change Immediately Post-Exposure From Baseline | Baseline, immediately post-exposure | Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Nasal epithelial lining (ELF) will be collected from participants at baseline within two weeks prior to first exposure, and at the following time points for each exposure: immediately after exiting the exposure chamber, and at 24 hours after the exposure. The IL-8 concentration will be determined in each ELF sample by immunoassay. The change in IL-8 concentrations from baseline to immediately Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3 to determine the effect of ozone on the production of nasal IL-8. |
| Interleukin-8 (IL-8) Concentrations in Nasal Epithelial Lining Fluid (ELF): Change 24 Hours Post-Exposure From Baseline | Baseline, 24 hours post-exposure | Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Nasal epithelial lining (ELF) will be collected from participants at baseline within two weeks prior to first exposure, and at the following time points for each exposure: immediately after exiting the exposure chamber, and at 24 hours after the exposure. The IL-8 concentration will be determined in each ELF sample by immunoassay. The change in IL-8 concentrations from baseline to 24 hours Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3 to determine the effect of ozone on the production of nasal IL-8. |
| Left Ventricular Strain (LVS): Change Immediately Post-Exposure From Baseline | Baseline and immediately post-exposure | Left ventricular strain will be assessed at baseline prior to exposure (within two weeks), and immediately after the exposure by measuring global longitudinal strain (GLS), an echocardiographic measure of myocardial mechanics. GLS is measured using speckle tracking, a technique by which small myocardial footprints, or speckles, are tracked over the cardiac cycle to enable quantification of left ventricular systolic function. GLS is more sensitive than traditional measures of ventricular function, such as ejection fraction, in detecting clinically inapparent but prognostically important decrements in contractility. The change in global longitudinal strain will be calculated to determine the effect of ozone on left ventricular strain. |
| Interleukin-6 (IL-6) Concentrations in Nasal Epithelial Lining Fluid (ELF): Change Immediately Post-Exposure From Baseline | Baseline, immediately post-exposure | Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Nasal epithelial lining (ELF) will be collected from participants at a baseline visit within two weeks prior to each exposure, and at the following time points for each exposure: immediately after exiting the exposure chamber, and at 24 hours after the exposure. The IL-6 concentration will be determined in each ELF sample by immunoassay. The change in IL-6 concentrations from baseline to immediately Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3 to determine the effect of ozone on the production of nasal IL-6. |
| Flow Mediated Dilation (FMD): Change Immediately Post-Exposure From Baseline | Baseline and immediately post-exposure | Participants will undergo assesment of flow-mediated brachial artery dilation by brachial ultrasound at baseline prior to exposure (within two weeks), and immediately after exposure to either FA or O3 to assess the impact of O3 exposure on endothelial function. Flow mediated dilation of the brachial artery (FMD) is a noninvasive index of vascular endothelial function. FMD is measured using high-frequency ultrasound, and is expressed as the percent change in arterial diameter in response to the reactive hyperemia induced by 5 minutes of forearm ischemia. Impaired endothelial function leads to atherosclerosis and is associated with an increased risk of cardiovascular events. |
| Change in Heart Rate Variability | baseline, immediately post exposure | Measure was not performed as the equipment (ECG leads and monitor recording heart rate and rhythm) belonged to the EPA and was not made available for this study |
| Nasal Epithelial Cell IL-6R Gene Expression: Relative mRNA Counts Immediately Post-Exposure (Baseline-corrected), Ozone vs Filtered Air | Screening visit and immediately post-exposure | RNA isolated from nasal epithelial cell biopsies collected at the screening visit (baseline) within six weeks prior to the first exposure and immediately after each exposure. RNA will be analyzed via real-time quantitative polymerase chain reaction (qPCR) to determine the impact of O3 on inflammatory gene expression. |
| Nasal Epithelial Cell IL-8 Gene Expression: Relative mRNA Counts Immediately Post-Exposure (Baseline-corrected), Ozone vs Filtered Air | Screening visit and immediately post-exposure | RNA isolated from nasal epithelial cell biopsies collected at the screening visit (baseline) within six weeks prior to the first exposure and immediately after each exposure. RNA will be analyzed via real-time quantitative polymerase chain reaction (qPCR) to determine the impact of O3 on inflammatory gene expression. |
| The Percentage of Predicted Forced Vital Capacity (% Predicted FVC): Change Immediately Post-Exposure From Baseline | Baseline, immediately post-exposure | Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Standard spirometry to obtain FEV1 and forced vital capacity (FVC) measurements will be done at baseline within two weeks prior to first exposure, and immediately after exiting the exposure chamber for each exposure. The % Predicted FVC will be calculated from measured versus expected values. The change in % Predicted FVC from baseline to immediately Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3 to determine the effect of ozone on the % Predicted FVC. |
| Nasal Epithelial Cell IL-1 Beta Gene Expression: Relative mRNA Counts Immediately Post-Exposure (Baseline-corrected), Ozone vs Filtered Air | Screening visit and immediately post-exposure | RNA isolated from nasal epithelial cell biopsies collected at the screening visit (baseline) within six weeks prior to the first exposure and immediately after each exposure. RNA will be analyzed via real-time quantitative polymerase chain reaction (qPCR) to determine the impact of O3 on inflammatory gene expression. |
| % Polymorphonuclear Leukocytes (PMN) in Induced Sputum: Change 24 Hours Post-Exposure From Screening Visit | Screening visit and 24 hours post-exposure | Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Induced sputum will be collected from participants after inhaled hypertonic saline. Induced sputum will be collected at the screening visit within six weeks prior to the first exposure, and at 24 hours after each exposure. The % PMN as a percentage of total inflammatory cells (total of monocytes and macrophages, PMN, eosinophils, basophils, lymphocytes, and bronchial epithelial cells) will be determined in each induced sputum collection by differential counts of cells on cytospin slides. The change in the values from baseline to 24 hours Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3. |
Countries
United States
Participant flow
Recruitment details
A total of 17 participants were screened between April 22, 2017 and May 1, 2019. Participants were recruited from a database of subjects at the Center for Environmental Medicine, Asthma and Lung Biology.
Pre-assignment details
Two participants did not meet inclusion criteria, and 1 withdrew before undergoing the second exposure. All participants were free from acute illness
Participants by arm
| Arm | Count |
|---|---|
| Filtered Air; Then Ozone Participants were exposed to filtered clean air for 6.5 hours, and after a minimum of a 2-week washout, they returned and were exposed to 0.06-0.08 PPM ozone for 6.5 hours. All participants wore a Health and Exposure Tracker (HET): Ozone and heart rate tracker during both exposures | 7 |
| Ozone; Then Filtered Air Participants were exposed to 0.06-0.08 PPM ozone for 6.5 hours, and after a minimum of a 2-week washout, they returned and were exposed to filtered clean air for 6.5 hours. All participants wore a Health and Exposure Tracker (HET): Ozone and heart rate tracker during both exposures | 7 |
| Total | 14 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| First Exposure | Withdrawal by Subject | 1 | 0 |
Baseline characteristics
| Characteristic | Filtered Air; Then Ozone | Total | Ozone; Then Filtered Air |
|---|---|---|---|
| Age, Continuous | 28.8 years | 31.22 years | 35.47 years |
| Ethnicity (NIH/OMB) Hispanic or Latino | 1 Participants | 2 Participants | 1 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 6 Participants | 12 Participants | 6 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Black or African American | 1 Participants | 3 Participants | 2 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 6 Participants | 11 Participants | 5 Participants |
| Region of Enrollment United States | 7 Participants | 14 Participants | 7 Participants |
| Sex: Female, Male Female | 2 Participants | 7 Participants | 5 Participants |
| Sex: Female, Male Male | 5 Participants | 7 Participants | 2 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 15 | 0 / 14 |
| other Total, other adverse events | 0 / 15 | 0 / 14 |
| serious Total, serious adverse events | 0 / 15 | 0 / 14 |
Outcome results
Primary
Change in % Polymorphonuclear Leukocytes (PMN) in Nasal Lavage Fluid 24 Hours Post-Exposure From Baseline
Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Nasal lavage fluid (NLF) will be collected from participants at a baseline visit within two weeks prior to each exposure, and at the following time points for each exposure: immediately after exiting the exposure chamber, and at 24 hours after the exposure. The % PMN as a percentage of total inflammatory cells (total of monocytes and macrophages, PMN, eosinophils, basophils, lymphocytes, and bronchial epithelial cells) will be determined in each NLF collection by differential counts of cells on cytospin slides. The change in the values from baseline to 24 hours Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3.
Time frame: Baseline, 24 hours post-exposure
Population: Only 5 participants had paired pre and 24h post-filtered air exposure samples and only 3 had paired pre and 24h post-ozone exposure samples of adequate quality for analysis. Only 1 participant had paired samples from both exposure periods. The remainder of samples were of poor quality and contained insufficient cells for analysis.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Filtered Air | Change in % Polymorphonuclear Leukocytes (PMN) in Nasal Lavage Fluid 24 Hours Post-Exposure From Baseline | 17.18 percent PMNs in nasal lavage fluid | Standard Error 16.76 |
| Ozone | Change in % Polymorphonuclear Leukocytes (PMN) in Nasal Lavage Fluid 24 Hours Post-Exposure From Baseline | -27.97 percent PMNs in nasal lavage fluid | Standard Error 31.67 |
Primary
Change in % Polymorphonuclear Leukocytes (PMN) in Nasal Lavage Fluid Immediately Post-Exposure From Baseline
Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Nasal lavage fluid (NLF) will be collected from participants at a baseline visit within two weeks prior to each exposure, and at the following time points for each exposure: immediately after exiting the exposure chamber, and at 24 hours after the exposure. The % PMN as a percentage of total inflammatory cells (total of monocytes and macrophages, PMN, eosinophils, basophils, lymphocytes, and bronchial epithelial cells) will be determined in each NLF collection by differential counts of cells on cytospin slides. The change in the values from baseline to immediately Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3.
Time frame: Baseline, immediately post-exposure
Population: Only 5 participants had paired pre and immediately post-filtered air exposure samples and only 3 had paired pre and immediately post-ozone exposure samples of adequate quality for analysis. Only 1 participant had paired samples from both exposure periods. The remainder of samples were of poor quality and contained insufficient cells for analysis.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Filtered Air | Change in % Polymorphonuclear Leukocytes (PMN) in Nasal Lavage Fluid Immediately Post-Exposure From Baseline | -1.02 percent PMNs in nasal lavage fluid | Standard Error 10.57 |
| Ozone | Change in % Polymorphonuclear Leukocytes (PMN) in Nasal Lavage Fluid Immediately Post-Exposure From Baseline | -6.8 percent PMNs in nasal lavage fluid | Standard Error 6.75 |
Secondary
Change in Heart Rate Variability
Measure was not performed as the equipment (ECG leads and monitor recording heart rate and rhythm) belonged to the EPA and was not made available for this study
Time frame: baseline, immediately post exposure
Population: No participants analyzed as equipment belonging to the EPA was not available
Secondary
Flow Mediated Dilation (FMD): Change Immediately Post-Exposure From Baseline
Participants will undergo assesment of flow-mediated brachial artery dilation by brachial ultrasound at baseline prior to exposure (within two weeks), and immediately after exposure to either FA or O3 to assess the impact of O3 exposure on endothelial function. Flow mediated dilation of the brachial artery (FMD) is a noninvasive index of vascular endothelial function. FMD is measured using high-frequency ultrasound, and is expressed as the percent change in arterial diameter in response to the reactive hyperemia induced by 5 minutes of forearm ischemia. Impaired endothelial function leads to atherosclerosis and is associated with an increased risk of cardiovascular events.
Time frame: Baseline and immediately post-exposure
Population: All participants that completed the study
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Filtered Air | Flow Mediated Dilation (FMD): Change Immediately Post-Exposure From Baseline | 1.09 percent change | Standard Error 1.02 |
| Ozone | Flow Mediated Dilation (FMD): Change Immediately Post-Exposure From Baseline | 1.25 percent change | Standard Error 1.04 |
p-value: 0.9ANOVA
Secondary
Interleukin-6 (IL-6) Concentrations in Nasal Epithelial Lining Fluid (ELF): Change 24 Hours Post-Exposure From Baseline
Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Nasal epithelial lining (ELF) will be collected from participants at baseline within two weeks prior to first exposure, and at the following time points for each exposure: immediately after exiting the exposure chamber, and at 24 hours after the exposure. The IL-6 concentration will be determined in each ELF sample by immunoassay. The change in IL-6 concentrations from baseline to 24 hours Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3 to determine the effect of ozone on the production of nasal IL-6.
Time frame: Baseline, 24 hours post-exposure
Population: All participants that completed the study
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Filtered Air | Interleukin-6 (IL-6) Concentrations in Nasal Epithelial Lining Fluid (ELF): Change 24 Hours Post-Exposure From Baseline | 4.15 pg/ml | Standard Error 2.57 |
| Ozone | Interleukin-6 (IL-6) Concentrations in Nasal Epithelial Lining Fluid (ELF): Change 24 Hours Post-Exposure From Baseline | 11.25 pg/ml | Standard Error 3.56 |
p-value: 0.1ANOVA
Secondary
Interleukin-6 (IL-6) Concentrations in Nasal Epithelial Lining Fluid (ELF): Change Immediately Post-Exposure From Baseline
Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Nasal epithelial lining (ELF) will be collected from participants at a baseline visit within two weeks prior to each exposure, and at the following time points for each exposure: immediately after exiting the exposure chamber, and at 24 hours after the exposure. The IL-6 concentration will be determined in each ELF sample by immunoassay. The change in IL-6 concentrations from baseline to immediately Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3 to determine the effect of ozone on the production of nasal IL-6.
Time frame: Baseline, immediately post-exposure
Population: All participants that completed the study
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Filtered Air | Interleukin-6 (IL-6) Concentrations in Nasal Epithelial Lining Fluid (ELF): Change Immediately Post-Exposure From Baseline | 2.28 pg/mL | Standard Error 2.01 |
| Ozone | Interleukin-6 (IL-6) Concentrations in Nasal Epithelial Lining Fluid (ELF): Change Immediately Post-Exposure From Baseline | 5.33 pg/mL | Standard Error 3.19 |
p-value: 0.46ANOVA
Secondary
Interleukin-8 (IL-8) Concentrations in Nasal Epithelial Lining Fluid (ELF): Change 24 Hours Post-Exposure From Baseline
Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Nasal epithelial lining (ELF) will be collected from participants at baseline within two weeks prior to first exposure, and at the following time points for each exposure: immediately after exiting the exposure chamber, and at 24 hours after the exposure. The IL-8 concentration will be determined in each ELF sample by immunoassay. The change in IL-8 concentrations from baseline to 24 hours Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3 to determine the effect of ozone on the production of nasal IL-8.
Time frame: Baseline, 24 hours post-exposure
Population: All participants that completed the study
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Filtered Air | Interleukin-8 (IL-8) Concentrations in Nasal Epithelial Lining Fluid (ELF): Change 24 Hours Post-Exposure From Baseline | 3524.77 pg/mL | Standard Error 2165.8 |
| Ozone | Interleukin-8 (IL-8) Concentrations in Nasal Epithelial Lining Fluid (ELF): Change 24 Hours Post-Exposure From Baseline | 6696.56 pg/mL | Standard Error 3032.59 |
p-value: 0.27ANOVA
Secondary
Interleukin-8 (IL-8) Concentrations in Nasal Epithelial Lining Fluid (ELF): Change Immediately Post-Exposure From Baseline
Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Nasal epithelial lining (ELF) will be collected from participants at baseline within two weeks prior to first exposure, and at the following time points for each exposure: immediately after exiting the exposure chamber, and at 24 hours after the exposure. The IL-8 concentration will be determined in each ELF sample by immunoassay. The change in IL-8 concentrations from baseline to immediately Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3 to determine the effect of ozone on the production of nasal IL-8.
Time frame: Baseline, immediately post-exposure
Population: All participants that completed the study
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Filtered Air | Interleukin-8 (IL-8) Concentrations in Nasal Epithelial Lining Fluid (ELF): Change Immediately Post-Exposure From Baseline | 2036.75 pg/mL | Standard Error 1518.94 |
| Ozone | Interleukin-8 (IL-8) Concentrations in Nasal Epithelial Lining Fluid (ELF): Change Immediately Post-Exposure From Baseline | 2939.08 pg/mL | Standard Error 1885.08 |
p-value: 0.69ANOVA
Secondary
Left Ventricular Strain (LVS): Change Immediately Post-Exposure From Baseline
Left ventricular strain will be assessed at baseline prior to exposure (within two weeks), and immediately after the exposure by measuring global longitudinal strain (GLS), an echocardiographic measure of myocardial mechanics. GLS is measured using speckle tracking, a technique by which small myocardial footprints, or speckles, are tracked over the cardiac cycle to enable quantification of left ventricular systolic function. GLS is more sensitive than traditional measures of ventricular function, such as ejection fraction, in detecting clinically inapparent but prognostically important decrements in contractility. The change in global longitudinal strain will be calculated to determine the effect of ozone on left ventricular strain.
Time frame: Baseline and immediately post-exposure
Population: One participant's LVS data was collected but was not able to undergo analysis due to the shutdown of university laboratories in response to the pandemic
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Filtered Air | Left Ventricular Strain (LVS): Change Immediately Post-Exposure From Baseline | 0.58 percent change | Standard Error 0.44 |
| Ozone | Left Ventricular Strain (LVS): Change Immediately Post-Exposure From Baseline | 0.06 percent change | Standard Error 0.63 |
p-value: 0.5ANOVA
Secondary
Nasal Epithelial Cell IL-1 Beta Gene Expression: Relative mRNA Counts Immediately Post-Exposure (Baseline-corrected), Ozone vs Filtered Air
RNA isolated from nasal epithelial cell biopsies collected at the screening visit (baseline) within six weeks prior to the first exposure and immediately after each exposure. RNA will be analyzed via real-time quantitative polymerase chain reaction (qPCR) to determine the impact of O3 on inflammatory gene expression.
Time frame: Screening visit and immediately post-exposure
Population: One participant did not have a pre-exposure nasal epithelial cell biopsy sample available for analysis.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Filtered Air | Nasal Epithelial Cell IL-1 Beta Gene Expression: Relative mRNA Counts Immediately Post-Exposure (Baseline-corrected), Ozone vs Filtered Air | -169.6 relative mRNA counts | Standard Deviation 317.5 |
| Ozone | Nasal Epithelial Cell IL-1 Beta Gene Expression: Relative mRNA Counts Immediately Post-Exposure (Baseline-corrected), Ozone vs Filtered Air | -147.4 relative mRNA counts | Standard Deviation 329.1 |
p-value: 0.54Wilcoxon signed rank test
Secondary
Nasal Epithelial Cell IL-6R Gene Expression: Relative mRNA Counts Immediately Post-Exposure (Baseline-corrected), Ozone vs Filtered Air
RNA isolated from nasal epithelial cell biopsies collected at the screening visit (baseline) within six weeks prior to the first exposure and immediately after each exposure. RNA will be analyzed via real-time quantitative polymerase chain reaction (qPCR) to determine the impact of O3 on inflammatory gene expression.
Time frame: Screening visit and immediately post-exposure
Population: One participant did not have a pre-exposure nasal epithelial cell biopsy sample available for analysis.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Filtered Air | Nasal Epithelial Cell IL-6R Gene Expression: Relative mRNA Counts Immediately Post-Exposure (Baseline-corrected), Ozone vs Filtered Air | -10.22 relative mRNA counts | Standard Deviation 38.5 |
| Ozone | Nasal Epithelial Cell IL-6R Gene Expression: Relative mRNA Counts Immediately Post-Exposure (Baseline-corrected), Ozone vs Filtered Air | -4.72 relative mRNA counts | Standard Deviation 25.77 |
p-value: 0.64Wilcoxon signed rank test
Secondary
Nasal Epithelial Cell IL-8 Gene Expression: Relative mRNA Counts Immediately Post-Exposure (Baseline-corrected), Ozone vs Filtered Air
RNA isolated from nasal epithelial cell biopsies collected at the screening visit (baseline) within six weeks prior to the first exposure and immediately after each exposure. RNA will be analyzed via real-time quantitative polymerase chain reaction (qPCR) to determine the impact of O3 on inflammatory gene expression.
Time frame: Screening visit and immediately post-exposure
Population: One participant did not have a pre-exposure nasal epithelial cell biopsy sample available for analysis.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Filtered Air | Nasal Epithelial Cell IL-8 Gene Expression: Relative mRNA Counts Immediately Post-Exposure (Baseline-corrected), Ozone vs Filtered Air | -537.7 relative mRNA counts | Standard Deviation 3470 |
| Ozone | Nasal Epithelial Cell IL-8 Gene Expression: Relative mRNA Counts Immediately Post-Exposure (Baseline-corrected), Ozone vs Filtered Air | 399.7 relative mRNA counts | Standard Deviation 5459 |
p-value: 0.79Wilcoxon signed rank test
Secondary
% Polymorphonuclear Leukocytes (PMN) in Induced Sputum: Change 24 Hours Post-Exposure From Screening Visit
Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Induced sputum will be collected from participants after inhaled hypertonic saline. Induced sputum will be collected at the screening visit within six weeks prior to the first exposure, and at 24 hours after each exposure. The % PMN as a percentage of total inflammatory cells (total of monocytes and macrophages, PMN, eosinophils, basophils, lymphocytes, and bronchial epithelial cells) will be determined in each induced sputum collection by differential counts of cells on cytospin slides. The change in the values from baseline to 24 hours Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3.
Time frame: Screening visit and 24 hours post-exposure
Population: Participants who produced induced sputum containing at least 60000 inflammatory cells at both the screening visit and at 24 hours after at least one exposure
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Filtered Air | % Polymorphonuclear Leukocytes (PMN) in Induced Sputum: Change 24 Hours Post-Exposure From Screening Visit | 12.04 percent PMN | Standard Error 5.22 |
| Ozone | % Polymorphonuclear Leukocytes (PMN) in Induced Sputum: Change 24 Hours Post-Exposure From Screening Visit | 21.86 percent PMN | Standard Error 7.74 |
p-value: 0.0481ANOVA
Secondary
The Percentage of Predicted Forced Expiratory Volume in One Second (% Predicted FEV1): Change Immediately Post-Exposure From Baseline
Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Standard spirometry to obtain FEV1 and forced vital capacity (FVC) measurements will be done at baseline within two weeks prior to first exposure, and immediately after exiting the exposure chamber for each exposure. The % Predicted FEV1 will be calculated from measured versus expected values. The change in % Predicted FEV1 from baseline to immediately Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3 to determine the effect of ozone on the % Predicted FEV1.
Time frame: Baseline, immediately post-exposure
Population: All participants that completed the study
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Filtered Air | The Percentage of Predicted Forced Expiratory Volume in One Second (% Predicted FEV1): Change Immediately Post-Exposure From Baseline | 0.79 percent predicted FEV1 | Standard Error 0.7 |
| Ozone | The Percentage of Predicted Forced Expiratory Volume in One Second (% Predicted FEV1): Change Immediately Post-Exposure From Baseline | -2.00 percent predicted FEV1 | Standard Error 0.7 |
p-value: 0.0179ANOVA
Secondary
The Percentage of Predicted Forced Vital Capacity (% Predicted FVC): Change Immediately Post-Exposure From Baseline
Participants will be exposed to either filtered air (FA), then ozone (O3), or O3, then FA. Standard spirometry to obtain FEV1 and forced vital capacity (FVC) measurements will be done at baseline within two weeks prior to first exposure, and immediately after exiting the exposure chamber for each exposure. The % Predicted FVC will be calculated from measured versus expected values. The change in % Predicted FVC from baseline to immediately Post-Exposure will be calculated for each participant for each exposure. Values will be compared between FA and O3 to determine the effect of ozone on the % Predicted FVC.
Time frame: Baseline, immediately post-exposure
Population: All participants that completed the study
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Filtered Air | The Percentage of Predicted Forced Vital Capacity (% Predicted FVC): Change Immediately Post-Exposure From Baseline | -0.3 percent predicted FEV1 | Standard Deviation 0.7 |
| Ozone | The Percentage of Predicted Forced Vital Capacity (% Predicted FVC): Change Immediately Post-Exposure From Baseline | -1.8 percent predicted FEV1 | Standard Deviation 0.5 |
p-value: 0.094ANOVA