Allergy, Asthma
Conditions
Keywords
asthma, dietary interventions, mouse allergy
Brief summary
Sulforaphane (SFN) is a naturally occurring isothiocyanate that is a potent inducer of Phase II enzymes which play a critical role in preventing oxidative stress (via activation of Nrf2). Broccoli sprouts (BS) contain the richest source of SFN. The main objectives of this study are to test the effect of broccoli sprouts (BS) on biomarkers of oxidative stress (OS), inflammation, basophil activation, and clinical outcomes in mouse allergen-induced asthma by (1) determining if BS improves lung function and airways symptom responses in mouse-sensitized adults with asthma undergoing environmental mouse allergen challenge (EMAC), (2) examining the effect of BS on OS, inflammation, and basophil activation, and (3) examining the effect of BS on changes in OS, inflammation, and basophil activation after EMAC.
Detailed description
After eligibility is confirmed, participants will be randomized to (a) placebo then BS or (b) BS then placebo. At randomization, baseline exhaled nitric oxide (eNO), forced expiratory volume at one second (FEV1), nasal epithelial gene expression, urinary OS biomarkers, serum inflammatory and OS biomarkers, and basophil activation will be assessed. These will be assessed again after 7 days on the assigned intervention at two time points: pre- and post-EMAC. The 1 week time period was chosen because previous studies have shown that daily ingestion of a broccoli sprout homogenate for three days resulted in upregulation of phase II enzyme gene expression in nasal epithelial cells. Following a 2-week washout period, this protocol will be repeated for the second intervention, phase II. The 2 week washout period will be sufficient as the half life of the extract of the active ingredient in broccoli sprouts, SFN, has been shown to be 1.8 hours.(16) Participants' diets will be assessed before and after each intervention with a Food Frequency Questionnaire and a questionnaire to capture intake of specific foods that are rich in SFN.
Interventions
OTHERBroccoli Sprouts
Broccoli Sprouts will be eaten daily in a sandwich form during the intervention period for broccoli sprouts.
OTHERAlfalfa Sprouts
Alfalfa sprouts will be eaten daily in a sandwich form during the intervention period for alfalfa sprouts.
Sponsors
National Institutes of Health (NIH)
National Institute of Environmental Health Sciences (NIEHS)
Massachusetts General Hospital
Johns Hopkins University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 49 Years
Healthy volunteers
No
Inclusion criteria
* Age 18-49 years * Physician-diagnosed asthma * No other major pulmonary disease such as cystic fibrosis or chronic obstructive pulmonary disease (COPD) * Mouse sensitization, defined by a positive skin prick test to mouse epithelial extract or positive mouse-specific immunoglobulin E (IgE) * Non-smoker
Exclusion criteria
* Severe or unstable asthma defined as requiring hospitalization in the previous year or intubation in the previous 2 years, or on high-dose inhaled corticosteroids or chronic oral corticosteroids * Baseline FEV1 and FEV1/forced vital capacity (FVC) \< 70% predicted * Positive skin prick test (SPT) to a pet currently living in the participant's home * Other significant medical issues such as heart disease or poorly controlled hypertension, or hypothyroidism * Pregnancy or nursing/breastfeeding mothers * On beta-blocker therapy * Taking anti-oxidant supplements * Unable to stop antihistamines prior to skin testing * Unable to stop medications that may interfere with allergen challenge responses prior to challenges. * The participant has food allergy to BS or AS. * Omalizumab use within the last 12 months. * Oral corticosteroid use within the last 2 weeks.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Forced Expiratory Volume at One Second (FEV1) | 30 days | The percentage change in FEV1 from the pre-challenge FEV1 value over the 1 hour mouse chamber exposure. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| All Participants the study population will be randomized in a 1:1 ratio to first eat broccoli sprouts followed by a washout period and then eat alfalfa sprouts, or to start with alfalfa sprouts followed by a washout and then eat broccoli sprouts | 1 |
| Total | 1 |
Baseline characteristics
| Characteristic | All Participants |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 1 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants |
| Race (NIH/OMB) Black or African American | 0 Participants |
| Race (NIH/OMB) More than one race | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) White | 1 Participants |
| Region of Enrollment United States | 1 Participants |
| Sex: Female, Male Female | 0 Participants |
| Sex: Female, Male Male | 1 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 1 |
| other Total, other adverse events | 0 / 1 |
| serious Total, serious adverse events | 1 / 1 |
Outcome results
Primary
Change in Forced Expiratory Volume at One Second (FEV1)
The percentage change in FEV1 from the pre-challenge FEV1 value over the 1 hour mouse chamber exposure.
Time frame: 30 days
Population: Trial was halted due to an adverse event after the second intervention. The participant could not complete the second challenge for data to be obtained.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Broccoli Sprouts | Change in Forced Expiratory Volume at One Second (FEV1) | -18 percent change |