Role of Cysteinyl Leukotrienes in the Pathogenesis of Asthma in Obesity

Study Overview
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Brief Summary
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The purpose of this study is to examine whether there are higher levels of cysteinyl leukotrienes in obese subjects than in non-obese subjects. Cysteinyl leukotrienes are pro-inflammatory substances that cause asthma by narrowing the airways of the lung. The investigators want to see if subjects with increased fat stores and therefore increased leptin, which is a fat-related protein that regulates leukotrienes, have increased levels of leukotrienes in the blood, lung and urine. The investigators would also like to determine the relationship between cysteinyl leukotrienes and exhaled nitric oxide levels in asthmatics with and without obesity. Nitric oxide is anti-inflammatory and suppresses leukotriene synthesis.

Detailed Description
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This is a cross-sectional observational study to characterize the association between obese asthmatics and the inflammatory mediators cysteinyl leukotrienes. Our hypothesis is that altered adipokine levels in obesity result in augmented cysteinyl leukotriene synthesis that play a significant role in the pathogenesis of asthma in these subjects.

Official Title
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Role of Cysteinyl Leukotrienes in the Pathogenesis of Asthma in Obesity

Conditions
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Asthma, Obesity

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18-65 yr old adults with asthma, non-smoking for at least one year Healthy non-smoking adults, aged 18-65 without asthma Heavy subjects with BMI > 30 kg/m2 Subjects with normal weight (BMI between 20-25 kg/m2) Subject not taking anti-leukotriene therapy (Singulair, Accolate, Zyflo) Exclusion Criteria: No chronic oral steroid use No recent history of infection No recent history of flare of lung disease

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Healthy non-asthmatic obese adults<br>Healthy non-asthmatic obese adults | |
| Healthy non-asthmatic non-obese adults<br>Healthy non-asthmatic non-obese adults | |
| Asthmatic obese adults<br>Asthmatic obese adults | |
| Asthmatic non-obese adults<br>Asthmatic non-obese adults | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma Leptin | Measurement of plasma leptin in obese and non obese asthmatics and non-asthmatic subjects from a single blood draw. | Observational: one time point from a blood draw after more than 6 hours fasting | 
| Exhaled Nitric Oxide (FeNO) | Exhaled breath nitic oxide ppb (averaged values from 2 exhalations per participant) | Observational: Two exhalations within 1 minute | 
| Urine Cysteinyl Leukotriene Per Creatinine | Urine inflammatory mediators measured from a single urine sample | sample taken over 5 minutes or less | 
| Ratio U Cys-LT/FeNO | Responsiveness to leukotriene modifier medication by measuring the urine cysteinyl leukotriene/exhaled nitric oxide ratio | sample taken over 5 minutes or less | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Asthma, Obesity