Redox Determinants of Severe Asthma (a Substudy of the Severe Asthma Research Program)

Study Overview
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Brief Summary
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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

Detailed Description
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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.

Official Title
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Redox Determinants of Severe Asthma: A Substudy of the NHLBI Severe Asthma Research Program

Conditions
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Asthma

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: At least 6 years old Asthma diagnosis by physician Current treatment with an inhaled corticosteroid medication Exclusion criteria: Bronchiectasis Cystic Fibrosis Chronic Obstructive Pulmonary Disease

Ages Eligible for Study
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Minimum Age: 6 Years
Maximum Age: 21 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Children with severe asthma<br>This group consists of children with severe asthma as defined per ATS workshop criteria (published in 2000). | |
| Children with non-severe asthma<br>This group includes children with asthma who do not meet the ATS criteria for severe asthma as outlined in the 2000 workshop report. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Exhaled Nitric Oxide at Baseline and Over the Observational Period | Exhaled nitric oxide concentrations as measured by collection of exhaled breath into a mylar bag | baseline and after 21 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Reduction in Breath pH | 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. | baseline and 21 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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severe asthma, poorly controlled asthma