Genetics of Asthma - Bronchoscopy Studies

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00644514
Recruitment Status : Terminated (grant funding no longer available)
First Posted : March 26, 2008
Last Update Posted : July 16, 2013
Information provided by (Responsible Party):
John Sundy, Duke University

Brief Summary:

The purpose of this study is to identify the mediators and genes in airway epithelial and BAL cells that are differentially regulated following inhalation of endotoxin lipopolysaccharide (LPS) among study participants with allergic asthma and normal phenotypes. This approach is designed to identify novel genes associated with both asthma pathogenesis and asthma susceptibility. LPS, or endotoxin, a cell wall component of gram-negative bacteria, is ubiquitous in the environment, and is thought to influence both susceptibility and severity of asthma.

240 subjects (healthy adult men and women (age >18-40) with and without atopy and asthma) will complete the screening evaluations in order to establish 3 study groups of 60 subjects each. Each qualified subject will undergo an inhaled LPS endotoxin challenge followed by bronchoscopy after 24 hours, which will consist of a bronchoalveolar lavage (BAL) and endobronchial brush biopsies. BAL involves squirting a small amount of sterile salt water into one of the airways then gently taking it back out through the bronchoscope. The brush sample involves gently moving a small brush back and forth in an airway to collect cell samples. Samples of whole blood will also be obtained at various time points. RNA will be isolated from these cell populations in order to assess differential gene expression expression using microarrays.

Condition or disease Intervention/treatment Phase
Atopic Asthma Healthy Biological: Endotoxin - lipopolysaccharide (LPS) Phase 1

Detailed Description:


Endotoxin or lipopolysaccharide (LPS), a cell wall component of gram-negative bacteria, is ubiquitous in the environment, and is often present in high concentrations in organic dusts, as well as in air pollution, and household dusts. There is convincing evidence that endotoxin exacerbates airflow obstruction and airway inflammation in allergic asthmatics. Additional findings indicate that allergic airways can enhance the response to inhaled endotoxin, and that endotoxin can enhance the airway response to allergens. However, when considering the interaction between endotoxin and allergens, the timing of the exposure appears to be critical. Emerging evidence suggests that early exposure to endotoxin, a potent inducer of Th1 type cytokines (IFN-g and IL-12), may minimize the risk of allergen sensitization which could has profound effects on reducing the risk of developing asthma in children. Independent of its effect in allergic asthma, several studies demonstrate that inhalation of air contaminated with endotoxin is associated with the classical features of asthma (reversible airflow obstruction and airway inflammation, and persistent airway hyperreactivity and airway remodeling). Epidemiological studies have shown that the concentration of inhaled endotoxin in the bioaerosol is strongly and consistently associated with reversible airflow obstruction among cotton workers, agricultural workers, and fiberglass workers. Importantly, the concentration of endotoxin in the bioaerosol is the most important occupational exposure associated with the development and progression of airway disease in agricultural workers. Experimentally, inhalation of endotoxin can cause reversible airflow obstruction and airway inflammation in previously unexposed healthy study subjects. The ability of the host to respond to endotoxin is highly variable, and is influenced in part by genetic factors.:

The rationale for this investigation is based on the following points:

  • asthma is caused in large part by both genetic susceptibility and environmental exposure,
  • a variety of immune and non-immune mechanisms can function independently or interactively to cause airway hyper-reactivity, airflow obstruction, airway inflammation, and airway remodeling,
  • environmental challenges can be used to "narrow the asthma phenotype" and allow one to investigate unique gene-environment interactions that are involved in the development of biologically specific forms of asthma,
  • genes that are over or under stimulated in the airway epithelia of asthmatics following inhalation challenge are important in the pathogenesis of asthma

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 17 participants
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: The Genetics of Environmental Asthma: LPS Inhalation and Bronchoscopy in Normal Subjects and Subjects With Mild Atopic Asthma
Study Start Date : September 2007
Actual Primary Completion Date : April 2008
Actual Study Completion Date : April 2008

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Asthma

Arm Intervention/treatment
Experimental: LPS endotoxin inh f/u bronchoscopy
Participants receive inhalation of LPS endotoxin, followed by bronchoscopy in this study.
Biological: Endotoxin - lipopolysaccharide (LPS)
Nebulized 5000EU, 10,000EU, 20,000EU endotoxin doses delivered to completion. Nebulized dose inhaled 30 minutes apart if no adverse events occur after the previous dose. Fiberoptic Bronchoscopy with Bronchoalveolar Lavage (BAL) and brush samples performed 24 hours after LPS nebulization.
Other Names:
  • Lipopolysaccharide (LPS)
  • NIH Clinical Center Reference Endotoxin

Primary Outcome Measures :
  1. Identify Genes in airway epithelial and Bronchoalveolar Lavage (BAL)that are differentially regulated following inhalation of LPS endotoxin. [ Time Frame: bronchoscopy performed 24 hours after inhalation of endotoxin ]

Secondary Outcome Measures :
  1. Identify mediators in airway epithelial and BAL cells that are differentially regulated following LPS inhalation. [ Time Frame: Bronchoscopy performed 24 hours post inhalation of endotoxin ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 40 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Allergic asthmatic, allergic non-asthmatic, or nonallergic nonasthmatic
  • Willing/able to give informed consent & adhere to visit/protocol schedules.
  • Screening visit laboratory, C-Xray, EKG, results within normal limits
  • Women of childbearing potential must have a negative serum pregnancy test
  • Screening Pulmonary function testing above study criteria parameters

Exclusion Criteria:

  • Systemic corticosteroid administration for asthma within the previous 90days
  • Antibiotic administration within the previous 30 days.
  • Viral respiratory infection within the previous 14 days.
  • History of severe asthma requiring intubation.
  • Occupational exposure to hay or grain dust.
  • Significant exposure history to cigarette smoke
  • Past or present history of allergen immunotherapy to within the last 10 yrs
  • Underlying illnesses that may result in altered lung function
  • Students or employees under direct supervision by protocol investigators are ineligible
  • Subjects allergic to medications used (or potentially used) in the study will be excluded.
  • Subjects using aspirin will be excluded
  • Subjects who abuse alcohol or illicit substances will be excluded
  • Medication use other than for asthma, allergies or contraception
  • Other medical or psychological conditions which, in the opinion of the investigator, might create undue risk to the subject or interfere with the subject's ability to comply with the protocol requirements
  • Nursing mothers
  • Other investigational medication within the last 30 days

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 identifier (NCT number): NCT00644514

United States, North Carolina
Duke University Medical Center
Durham, North Carolina, United States, 27710
Sponsors and Collaborators
John Sundy
Principal Investigator: John S Sundy, M.D., PhD Duke University

Responsible Party: John Sundy, Associate Professor of Medicine, Duke University Identifier: NCT00644514     History of Changes
Other Study ID Numbers: Pro00001166
12496-CP-001A ( Other Identifier: NIEHS )
First Posted: March 26, 2008    Key Record Dates
Last Update Posted: July 16, 2013
Last Verified: July 2013

Keywords provided by John Sundy, Duke University:
LPS endotoxin

Additional relevant MeSH terms:
Bronchial Diseases
Respiratory Tract Diseases
Lung Diseases, Obstructive
Lung Diseases
Respiratory Hypersensitivity
Hypersensitivity, Immediate
Immune System Diseases