Genetic Susceptibility to Ozone in Mild Asthmatic Volunteers

• Status: Completed
• Trial end date: 2015-11-01
• Target enrollment: 0
• Participant gender: All

Summary

Recent reports have shown that people with asthma who have a particular gene, known as the GSTM1 null gene, are more susceptible to the effect of air pollutants. The purpose of this research study is to learn if volunteers who have asthma and have a GSTM1 null gene have increased response (change in lung function and increase in lung cells collected from sputum) compared to volunteers with asthma who have the GSTM1 sufficient gene when challenged with 0.4 ppm ozone during intermittent exercise. The principal purpose of this study is to identify hyper-responsive, responsive and non-responsive groups of human subjects with mild asthma based on their airway neutrophilic response to ozone exposure, and to perform analyses on DNA from airway cells to explore possible differences in genetic profiles between the three groups. An additional pilot aim is to compare expression of a small number of specific genes of interest in a subset of ozone-responsive and ozone-non-responsive subjects with mild asthma.

• Phase: N/A
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: University of North Carolina, Chapel Hill
• Collaborator: Environmental Protection Agency (EPA)

Criteria

Inclusion Criteria:

• healthy volunteers with mild asthma

• Normal lung function,

• Oxygen saturation of > 94 %

• Normal blood pressure

Exclusion Criteria:

• A history of significant chronic illnesses

• Allergy to any medications which may be used or prescribed in the course of this study (albuterol, acetaminophen, aspirin or non-steroidal anti-inflammatory agents, corticosteroids, lactose, polyethylene glycol)

• Positive pregnancy test within 48 hours of the time of challenge

• Subjects currently taking medications which may impact the results of the ozone challenge, interfere with any other medications potentially used in the study (to include steroids, beta antagonists, non-steroidal anti-inflammatory agents) or suggest an ongoing illness (such as antibiotics).

• Mega doses of vitamins and supplements, homeopathic/naturopathic medicines

• Any acute, non-chronic, medical conditions occurring in the prior two weeks. Such illnesses must be totally resolved symptomatically for 2 weeks and documentation of normal lung function must be obtained.

• Unspecified illnesses, which in the judgment of the investigator might increase the risk associated with ozone inhalation challenge, will be a basis for exclusion.

• Physician directed emergency treatment for an asthma exacerbation within the preceding 12 months.

• Use of systemic steroid therapy within the preceding 12 months.

• > 0.5 pack year history of tobacco use

• Use of inhaled steroids, cromolyn or leukotriene inhibitors initiated within the past month (except for use of cromolyn exclusively prior to exercise). Patients must be on a stable regimen of therapy.

• Use of daily theophylline within the past month.

• Pregnancy or nursing a baby.

• Nighttime symptoms of cough or wheeze greater than 1x/week at baseline (not during a clearly recognized viral induced asthma exacerbation) which would be characteristic of a person of moderate or severe persistent asthma as outlined in the current NHLBI guidelines for diagnosis and management of asthma.

• Exacerbation of asthma more than 2x/week which would be characteristic of a person with moderate or severe persistent asthma as outlined in the current NHLBI guidelines for diagnosis and management of asthma.

• Daily requirement for albuterol due to asthma symptoms (cough, wheeze, chest tightness) which would be characteristic of a person of moderate or severe persistent asthma as outlined in the current NHLBI guidelines for diagnosis and management of asthma. (Not to include prophylactic use of albuterol prior to exercise).

• Dosing level of an inhaled steroid must be consistent with mild episodic asthma as outlined by the NHLBI NAEPP guidelines. Use of inhaled steroid at doses typically used for moderate or severe asthma will result in exclusion of that individual from the protocol.

• Students or staff members who work directly for the PI, Dr David Peden, are excluded from study participation