Redox Determinants of Severe Asthma (a Substudy of the Severe Asthma Research Program) (SARP)
Hypotheses: 1) Airway pH regulation is abnormal in severe asthma; 2) In severe asthma, there is formation of cytotoxic nitrogen oxides and loss of beneficial nitrogen oxides in the airways
|Study Design:||Observational Model: Cohort
Time Perspective: Prospective
|Official Title:||Redox Determinants of Severe Asthma: A Substudy of the NHLBI Severe Asthma Research Program|
- Exhaled Nitric Oxide at Baseline and Over the Observational Period [ Time Frame: baseline and after 21 days ] [ Designated as safety issue: No ]Exhaled nitric oxide concentrations as measured by collection of exhaled breath into a mylar bag
- Reduction in Breath pH [ Time Frame: baseline and 21 days ] [ Designated as safety issue: No ]Breath condensate pH was measured by the RTube (trademark) device. This device is a plastic tube with a one-way exhalation valve and a chilled aluminum sleeve. pH (the log of hydrogen ion concentration) was measured using an Orion pH meter and probe calibrated in 4.0, 7.0, and 10.0 pH solutions.
|Study Start Date:||January 2003|
|Study Completion Date:||June 2011|
|Primary Completion Date:||June 2011 (Final data collection date for primary outcome measure)|
Children with severe asthma
This group consists of children with severe asthma as defined per ATS workshop criteria (published in 2000).
Children with non-severe asthma
This group includes children with asthma who do not meet the ATS criteria for severe asthma as outlined in the 2000 workshop report.
Specific Aim 1:Test hypothesis that airway pH regulation is abnormal in severe asthma.
1a) Determine the effects of systemic corticosteroids on breath pH in children with severe and mild to moderate asthma.
1b) Examine whether breath condensate pH and other biomarkers of oxidant stress can predict clinical outcomes in children with severe and mild to moderate asthma.
1c) Identify whether increased Th1/Th2 cytokine ratio, and abnormalities in airway glutaminase, G-SNO-reductase, VATPase, and carbonic anhydrase are associated with airway pH disturbance in children with severe asthma.
1d) Test whether rhinovirus infections, which reduce airway pH, persist longer or are more frequent in children with severe asthma than in children with mild to moderate asthma.
1e) Examine the relationship between gastroesophageal reflux and proximal airway pH in children with severe asthma and mild to moderate asthma.
|United States, Georgia|
|Emory Childrens Center|
|Atlanta, Georgia, United States, 30322|
|Principal Investigator:||W G Teague, MD||University of Virginia|