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

This study has been completed.
Sponsor:
Collaborator:
Information provided by:
Emory University
ClinicalTrials.gov Identifier:
NCT00615498
First received: February 4, 2008
Last updated: July 30, 2013
Last verified: July 2013
  Purpose

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
Asthma

Study Type: Observational
Study Design: 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

Resource links provided by NLM:


Further study details as provided by Emory University:

Primary Outcome Measures:
  • 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 ] [ Designated as safety issue: No ]
  • 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 ] [ Designated as safety issue: No ]

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.


Estimated Enrollment: 80
Study Start Date: July 2006
Study Completion Date: September 2008
Primary Completion Date: September 2008 (Final data collection date for primary outcome measure)
Groups/Cohorts
Surgical cases
Subjects who are undergoing bariatric surgery
Controls
Subjects who qualify for bariatric surgery but do not undergo the procedure

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.

  Eligibility

Ages Eligible for Study:   18 Years to 70 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population

Obese asthmatics

Criteria

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
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00615498

Locations
United States, Georgia
Emory University, Emory Crawford Long Hospital, Clinical Research Center
Atlanta, Georgia, United States, 30308
Sponsors and Collaborators
Emory University
  More Information

No publications provided

Responsible Party: Fernando Holguin, MD, MPH, Emory University
ClinicalTrials.gov Identifier: NCT00615498     History of Changes
Other Study ID Numbers: IRB00000064
Study First Received: February 4, 2008
Last Updated: July 30, 2013
Health Authority: United States: Institutional Review Board

Keywords provided by Emory University:
Asthma, obesity, bariatric

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

ClinicalTrials.gov processed this record on July 24, 2014