Effect of a Component of Fish Oil on Exercise-Induced Bronchoconstriction and Airway Inflammation in Asthma

Study Overview
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Brief Summary
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Docosahexaenoic acid (DHA) is a component of fish oil that is known to support a healthy cardiovascular system, maintain brain function, reduce depression, and improve inflammatory diseases. The study hypothesis is that DHA supplementation will diminish exercise-induced bronchoconstriction and airway inflammation as compared to placebo.

Detailed Description
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To date, fish oil supplementation studies in patients with asthma have used a combination of omega-3 polyunsaturated fatty acids. A study on the specific formula that is most effective in preventing exercise-induced bronchoconstriction (EIB) has yet to be conducted in humans. Nevertheless, it has been shown that a docosahexaenoic acid (DHA) metabolite, protectin D1, is involved in the active resolution of airway inflammation and that its concentration is greater in healthy control subjects' exhaled breath condensates as compared to patients with asthma during a clinical exacerbation. Supplementing asthmatics with DHA could enable an increased availability of protectin D1 to help resolve airway inflammation during an asthma attack. Furthermore, DHA is known to support a healthy cardiovascular system, maintain brain function, and reduce depression in addition to alleviating inflammatory diseases. Thus, pure DHA supplementation could help patients manage their asthma while providing for their overall health. The main aim of this study is to determine whether pure DHA can attenuate EIB and airway inflammation in adults with asthma. It is hypothesized that DHA supplementation will diminish EIB and airway inflammation compared to placebo.

Official Title
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Docosahexaenoic Acid (DHA) as a Nutritional Treatment for Exercise-Induced Bronchoconstriction and Airway Inflammation in Asthma

Conditions
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Asthma

Intervention / Treatment
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* Dietary Supplement: Docosahexaenoic Acid
* Dietary Supplement: Placebo Docosahexaenoic Acid


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnosis of asthma, based on medication use as well as history and symptoms as outlined in the NHLBI Guidelines for the Diagnosis and Management of Asthma Diagnosis of EIB, based on a ≥10% fall in FEV1, a measure of lung function, after dry air eucapnic voluntary hyperventilation (EVH), a simulated exercise challenge Not currently taking asthma maintenance medication or physician approval to discontinue current asthma medication for the duration of the study Not currently taking any fish oil supplements above the level recommended for adequate intake (if currently taking supplements, can participate if the subject stops taking the supplements for 2 weeks before starting the study and throughout the study) Agree to limit fish consumption to 1 fish meal per week throughout the study Exclusion Criteria: Post-EVH FEV1 (the amount of air blown out in the first second of a forced exhalation) decreases by more than 50% compared to the subject's resting FEV1 at the first lab testing session Pregnancy History of cardiovascular disease, including hyperlipidemia (high cholesterol) and hypertension (high blood pressure) History of bleeding disorders or delayed clotting time History of diabetes History of seizures Allergy to fish oil Allergy to corn or soy products (placebo is a mixture of corn and soy oil)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 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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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo Docosahexaenoic Acid (DHA)<br>Eight subjects will take 8 placebo DHA capsules per day for 3 weeks. | Dietary Supplement: Placebo Docosahexaenoic Acid<br>* 8 placebo docosahexaenoic acid (corn and soy oil blend) capsules per day for 3 weeks.<br>* Other names: Soy Oil;|
| Experimental: Active Docosahexaenoic Acid (DHA)<br>Eight subjects will take 8 active DHA capsules per day for 3 weeks. | Dietary Supplement: Docosahexaenoic Acid<br>* 8 docosahexaenoic acid (4.0 grams) capsules per day for 3 weeks.<br>* Other names: DHA;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pulmonary Function (Percent Change in FEV1, measured in Liters) | The percent change in FEV1 is the percent change in the volume of air exhaled during the first second of a forced exhalation as measured before and after the surrogate exercise challenge. | 8 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| DHA Metabolite Concentration in Exhaled Breath Condensate | The concentration (ng/mL) of the DHA metabolites protectin D1 and 17S-hydroxy-docosahexaenoic acid in exhaled breath condensate will be measured using liquid chromatography. | 8 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Asthma, Exercise-Induced Bronchoconstriction, Inflammation, Airway, Fish Oil, Docosahexaenoic Acid, DHA