Trial Outcomes & Findings for Mechanisms of Ozone-Induced Alterations in Efferocytosis and Phagocytosis (NCT NCT03646877)
NCT ID: NCT03646877
Last Updated: 2026-06-15
Results Overview
Efferocytosis is defined by determining the number of apoptotic PMNs phagocytized by alveolar macrophages (BAL cytospins) versus the total number of macrophages ('efferocytic index'). The efferocytic index is a measure of how efficiently macrophages engulf and clear apoptotic (dying) cells. It can be determined by counting the number of macrophages that have a phagocytosed apoptotic body and dividing it by the total number of macrophages counted. A higher value is considered better.
COMPLETED
PHASE1
35 participants
Baseline, 21 days
2026-06-15
Participant Flow
Subjects were recruited from Duke University campus and surrounding Durham, NC, community using advertisement in newspapers, mailings, and the campus student newspaper. Subjects were screened to determine eligibility per protocol inclusion and exclusion criteria.
Participant milestones
| Measure |
Ozone (O3), Then Filtered Air (FA)
The O3 level during the exposures will be 200 ppb, which has previously been used in human exposure studies without short or long term, untoward side effects (and comparable to peak levels attained during the summer in the Raleigh-Durham area of North Carolina).
Ozone: Subjects will perform alternating 15 minutes rest with 15 minutes treadmill walk exercise periods for 135 minutes in while breathing Ozone (O3).
Control will be treadmill walk with filtered room air in chamber.
Filtered Air: Subjects will perform alternating 15 minutes rest with 15 minutes treadmill walk exercise periods for 135 minutes in while breathing filtered air.
|
Filtered Air (FA), Then Ozone (O3)
Control will be treadmill walk with filtered room air in chamber.
Filtered Air: Subjects will perform alternating 15 minutes rest with 15 minutes treadmill walk exercise periods for 135 minutes in while breathing filtered air.
The O3 level during the exposures will be 200 ppb, which has previously been used in human exposure studies without short or long term, untoward side effects (and comparable to peak levels attained during the summer in the Raleigh-Durham area of North Carolina).
Ozone: Subjects will perform alternating 15 minutes rest with 15 minutes treadmill walk exercise periods for 135 minutes in while breathing Ozone (O3).
|
|---|---|---|
|
Overall Study
STARTED
|
17
|
18
|
|
Overall Study
COMPLETED
|
7
|
12
|
|
Overall Study
NOT COMPLETED
|
10
|
6
|
Reasons for withdrawal
Withdrawal data not reported
Baseline Characteristics
Mechanisms of Ozone-Induced Alterations in Efferocytosis and Phagocytosis
Baseline characteristics by cohort
| Measure |
Ozone (O3) and Filtered Air (FA)
n=19 Participants
The O3 level during the exposures will be 200 ppb, which has previously been used in human exposure studies without short or long term, untoward side effects (and comparable to peak levels attained during the summer in the Raleigh-Durham area of North Carolina) (REF - Bromberg review).
Ozone: Subjects will perform alternating 15 minutes rest with 15 minutes treadmill walk exercise periods for 135 minutes in while breathing Ozone (O3).
Control will be treadmill walk with filtered room air in chamber.
Filtered Air: Subjects will perform alternating 15 minutes rest with 15 minutes treadmill walk exercise periods for 135 minutes in while breathing filtered air.
|
|---|---|
|
Age, Continuous
|
23.75 years
STANDARD_DEVIATION 3.31 • n=20 Participants
|
|
Sex: Female, Male
Female
|
7 Participants
n=20 Participants
|
|
Sex: Female, Male
Male
|
12 Participants
n=20 Participants
|
|
Ethnicity (NIH/OMB)
Hispanic or Latino
|
5 Participants
n=20 Participants
|
|
Ethnicity (NIH/OMB)
Not Hispanic or Latino
|
14 Participants
n=20 Participants
|
|
Ethnicity (NIH/OMB)
Unknown or Not Reported
|
0 Participants
n=20 Participants
|
|
Race (NIH/OMB)
American Indian or Alaska Native
|
0 Participants
n=20 Participants
|
|
Race (NIH/OMB)
Asian
|
5 Participants
n=20 Participants
|
|
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
|
0 Participants
n=20 Participants
|
|
Race (NIH/OMB)
Black or African American
|
3 Participants
n=20 Participants
|
|
Race (NIH/OMB)
White
|
11 Participants
n=20 Participants
|
|
Race (NIH/OMB)
More than one race
|
0 Participants
n=20 Participants
|
|
Race (NIH/OMB)
Unknown or Not Reported
|
0 Participants
n=20 Participants
|
|
Region of Enrollment
United States
|
19 Participants
n=20 Participants
|
PRIMARY outcome
Timeframe: Baseline, 21 daysPopulation: Participants with complete data sets for both O3 and FA.
Efferocytosis is defined by determining the number of apoptotic PMNs phagocytized by alveolar macrophages (BAL cytospins) versus the total number of macrophages ('efferocytic index'). The efferocytic index is a measure of how efficiently macrophages engulf and clear apoptotic (dying) cells. It can be determined by counting the number of macrophages that have a phagocytosed apoptotic body and dividing it by the total number of macrophages counted. A higher value is considered better.
Outcome measures
| Measure |
Ozone (O3)
n=8 Participants
The O3 level during the exposures will be 200 ppb, which has previously been used in human exposure studies without short or long term, untoward side effects (and comparable to peak levels attained during the summer in the Raleigh-Durham area of North Carolina).
Ozone: Subjects will perform alternating 15 minutes rest with 15 minutes treadmill walk exercise periods for 135 minutes in while breathing Ozone (O3).
|
Filtered Air (FA)
n=8 Participants
Control will be treadmill walk with filtered room air in chamber.
Filtered Air: Subjects will perform alternating 15 minutes rest with 15 minutes treadmill walk exercise periods for 135 minutes in while breathing filtered air.
|
|---|---|---|
|
Change in Ozone Induced Efferocytosis of Lung Macrophages (Ability to Clear Dead or Dying Cells)
|
0.478 ratio
Standard Deviation 0.089
|
0.470 ratio
Standard Deviation 0.090
|
PRIMARY outcome
Timeframe: Baseline, 21 daysPopulation: Data not collected.
Bronchoalveolar macrophages are incubated with pHrodo™ dye-labeled particles. Macrophage phagocytosis will be defined by determining the number of macrophages that contain fluorescent particles versus the total macrophages. Cell free hemoglobin and soluble CD163 - both are measured by commercial ELISA kit.
Outcome measures
Outcome data not reported
SECONDARY outcome
Timeframe: Baseline, 21 daysPopulation: Participants with complete data sets for both O3 and FA.
Measured by spectroscopy.
Outcome measures
| Measure |
Ozone (O3)
n=19 Participants
The O3 level during the exposures will be 200 ppb, which has previously been used in human exposure studies without short or long term, untoward side effects (and comparable to peak levels attained during the summer in the Raleigh-Durham area of North Carolina).
Ozone: Subjects will perform alternating 15 minutes rest with 15 minutes treadmill walk exercise periods for 135 minutes in while breathing Ozone (O3).
|
Filtered Air (FA)
n=19 Participants
Control will be treadmill walk with filtered room air in chamber.
Filtered Air: Subjects will perform alternating 15 minutes rest with 15 minutes treadmill walk exercise periods for 135 minutes in while breathing filtered air.
|
|---|---|---|
|
Change in Ozone Induced Increase in Cell Free Hemoglobin in Bronchoalveolar Lavage Fluid
|
0.0000921391 micromolar (uM)
Standard Deviation 0.0000261954
|
0.000112267 micromolar (uM)
Standard Deviation 0.0000273103
|
SECONDARY outcome
Timeframe: Baseline, 21 daysPopulation: Participants with complete data sets for both O3 and FA.
Measured by enzyme-linked immunosorbent assay (ELISA)
Outcome measures
| Measure |
Ozone (O3)
n=19 Participants
The O3 level during the exposures will be 200 ppb, which has previously been used in human exposure studies without short or long term, untoward side effects (and comparable to peak levels attained during the summer in the Raleigh-Durham area of North Carolina).
Ozone: Subjects will perform alternating 15 minutes rest with 15 minutes treadmill walk exercise periods for 135 minutes in while breathing Ozone (O3).
|
Filtered Air (FA)
n=19 Participants
Control will be treadmill walk with filtered room air in chamber.
Filtered Air: Subjects will perform alternating 15 minutes rest with 15 minutes treadmill walk exercise periods for 135 minutes in while breathing filtered air.
|
|---|---|---|
|
Change in Ozone Induced Increase in Soluble CD163 in Bronchoalveolar Lavage Fluid
|
96.03 ng/mL
Standard Deviation 57.97
|
97.16 ng/mL
Standard Deviation 47.92
|
Adverse Events
Ozone (O3)
Filtered Air (FA)
Serious adverse events
Adverse event data not reported
Other adverse events
| Measure |
Ozone (O3)
n=35 participants at risk
The O3 level during the exposures will be 200 ppb, which has previously been used in human exposure studies without short or long term, untoward side effects (and comparable to peak levels attained during the summer in the Raleigh-Durham area of North Carolina) (REF - Bromberg review).
Ozone: Subjects will perform alternating 15 minutes rest with 15 minutes treadmill walk exercise periods for 135 minutes in while breathing Ozone (O3).
|
Filtered Air (FA)
n=35 participants at risk
Control will be treadmill walk with filtered room air in chamber.
Filtered Air: Subjects will perform alternating 15 minutes rest with 15 minutes treadmill walk exercise periods for 135 minutes in while breathing filtered air.
|
|---|---|---|
|
Nervous system disorders
Near syncope
|
2.9%
1/35 • Up to 21 days
All participants received both interventions.
|
0.00%
0/35 • Up to 21 days
All participants received both interventions.
|
Additional Information
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place