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Study to Evaluate the Effects of Weight Loss on Airway Inflammation and Mechanics in Subjects With Asthma (Asthma-Bariatric Surgery Study)

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ClinicalTrials.gov Identifier: NCT00615498
Recruitment Status : Completed
First Posted : February 14, 2008
Last Update Posted : July 31, 2013
National Institutes of Health (NIH)
Information provided by:
Emory University

Brief Summary:

Current research shows that obesity greatly increases the risk of developing asthma. Although the two conditions are clearly related, experts do not fully understand why they are linked. Some researchers believe that hormones released in the fat cells (adipokines) play a role. Others believe that excess weight pressing on the lungs triggers the hyperreactive response in the airways that is typical of asthma.

The goal of the Asthma-Bariatric Surgery Study is to determine how weight loss affects lung function and various biological parameters. Bariatric (weight loss) surgery refers to the various surgical procedures performed to treat obesity. Specifically, this study is designed to answer the following questions:

  • Does bariatric surgery help patients control their asthma?
  • How much asthma control can be achieved through weight loss?
  • How does weight loss influence lung function?

Participants in this observational research study will be asked to complete study visits at enrollment, 1 month, 6 months, and 12 months. Questionnaires, pulmonary function tests, and blood samples will be required at each time point.

This research study is observational only; it does not cover the cost of (or provide) bariatric surgery. Optional genetic and bronchoscopy substudies are included as well.

Condition or disease

Detailed Description:
This study is designed to explain the unexpected effects of obesity on NO bioavailability in the airways of asthmatics: Specifically, that obesity induces systemic oxidative stress in part through increased production of reactive oxygen species (ROS) in adipose tissue and, in parallel (or as a consequence), increased systemic levels of tumor necrosis factor (TNF-α)and 8-isoprostanes. Furthermore, it creates an imbalance in the regulation of protective anti-oxidant thiol/disulfide pairs such as glutathione/glutathione disulfide. We hypothesize that in asthmatics, the lung is a target-organ of this obesity-related systemic oxidative stress. This is manifested as increased oxidation of airway NO into nitrate and reactive nitrogen species (RNS) including peroxynitrate and nitrotyrosine, thereby reducing NO bioavailability and exhaled NO levels. NO has many key physiological properties including bronchodilation, anti-tumoral/bactericidal activity, and anti-inflammatory and anti-oxidative activity. Thus, reduced NO bioavailability in obese asthmatics could favor increased bronchoconstriction and impair the lung's ability to respond to further oxidative or inflammatory challenges. Therefore, we hypothesize that: 1) obesity causes redox stress in the airway, which in turn decreases the bioavailability of NO by shunting it into RNS, 2) that weight loss will decrease systemic oxidative stress and thereby increase NO bioavailability due to decreased oxidation into RNS, and 3) that by decreasing systemic oxidative stress, weight loss will reduce bronchial hyper-reactivity.

Study Type : Observational
Estimated Enrollment : 80 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Study to Evaluate the Effects of Weight Loss on Airway Inflammation and Mechanics in Subjects With Asthma
Study Start Date : July 2006
Primary Completion Date : September 2008
Study Completion Date : September 2008

Resource links provided by the National Library of Medicine

U.S. FDA Resources

Surgical cases
Subjects who are undergoing bariatric surgery
Subjects who qualify for bariatric surgery but do not undergo the procedure

Primary Outcome Measures :
  1. To measure levels of exhaled nitric oxide, reactive nitrogen species, exhaled biomarkers of lipid peroxidation, asthma quality of life, airway function (spirometry and response to methacholine), and degree of asthma control [ Time Frame: Enrollment, 1 month, 6 months, and 1 year ]
  2. To measure systemic markers of redox stress and inflammation, including plasma levels of adipokines, adiposity-related cytokines (IL-6, TNF-α), GSH/GSSG, 8-isoprostanes, and leukotrienes [ Time Frame: Enrollment, 1 month, 6 months, and 1 year ]

Biospecimen Retention:   Samples With DNA
Blood and exhaled breath condensate samples will obtained at all time points (baseline, 1 month, 6 months, and 1 year.

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 70 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Obese asthmatics

Inclusion Criteria:

  • Non-smoker, or a limited smoking history
  • Meet criteria for bariatric surgery according to NIH guidelines

Exclusion Criteria:

  • Illicit drug use
  • Greater than 10 pack-year history of cigarette smoking
  • Other significant lung pathology
  • Other significant non-pulmonary co-morbidities

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00615498

United States, Georgia
Emory University, Emory Crawford Long Hospital, Clinical Research Center
Atlanta, Georgia, United States, 30308
Sponsors and Collaborators
Emory University
National Institutes of Health (NIH)

Responsible Party: Fernando Holguin, MD, MPH, Emory University
ClinicalTrials.gov Identifier: NCT00615498     History of Changes
Other Study ID Numbers: IRB00000064
First Posted: February 14, 2008    Key Record Dates
Last Update Posted: July 31, 2013
Last Verified: July 2013

Keywords provided by Emory University:
Asthma, obesity, bariatric

Additional relevant MeSH terms:
Weight Loss
Bronchial Diseases
Respiratory Tract Diseases
Lung Diseases, Obstructive
Lung Diseases
Respiratory Hypersensitivity
Hypersensitivity, Immediate
Immune System Diseases
Pathologic Processes
Body Weight Changes
Body Weight
Signs and Symptoms