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Observational Study on Microglia Activation in Asthma

This study aims to understand how asthma affects your brain and if airway inflammation (swelling in your breathing tubes) is linked to feelings of depression and anxiety. Researchers will use a special imaging scan called a PET scan to look for "neuroinflammation" (inflammation in the brain) by tracking a substance called [18F]FEPPA. This substance helps identify activated microglia, which are brain cells involved in inflammation. You might be eligible if you are 18-75 years old and have a doctor's diagnosis of asthma for at least six months. The study plans to enroll 50 participants, but its current status is unclear.

Study design
This is an observational study, meaning researchers will observe participants without assigning specific treatments. It plans to enroll 50 participants.
What's involved
You will have 6 visits, complete questionnaires and computer tasks, undergo allergy skin tests, breathing tests including two whole lung allergen challenges, give four blood samples, and complete brain imaging scans.
Compensation
Not stated in the trial record.
Follow-up
Neuroinflammation will be measured via PET scan for up to 9 days.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT04307667

Microglia Activation in Asthma

Recruiting
Not specifiedAges 18–75Observational
University of Wisconsin, Madison
~50 participants
Updated 2026-06-01 on ClinicalTrials.gov
What's tested:Whole lung antigen challenge (WLAC)[18F]FEPPA

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Presence of Neuroinflammation measured by TSPO observed via PET scan
Measured over up to 9 days

Conditions

Asthma

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NCT04307667

Where you'd take part

This study runs at 1 site. They're the same protocol — you choose where, and that choice sets who your contact draft is addressed to.

  • University of Wisconsin Madison

    Madison, Wisconsinno site contact published

    Recruiting

Sites open and close at different times, so the status above is per site — it can differ from the study's overall status.

Study leadership

  • Melissa Rosenkranz · PRINCIPAL_INVESTIGATOR · Center for Healthy Minds

Who to contact

Rachel Kaspari
[email protected]
608-263-0524
Email the study team

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Eligibility criteria

Inclusion

Individuals with no health concerns that might affect the outcome of the study.
Age 18-75 years of age.
Physician diagnosis of asthma for at least six months prior to screening (can be determined at the discretion of an asthma/allergy physician member of the study team). Mild asthma will be defined as asthma that is well controlled with low-intensity treatment, e.g., SABA alone, as-needed low-dose ICS-LABA, or low-dose ICS plus as-needed SABA.
An increase in FEV1 \> 10% predicted after up to 8 puffs of albuterol OR positive methacholine defined as PD20 ≤ 400 mcg. (Historical data that is approved by the investigator is acceptable).
FEV1 ≥ 75% predicted at screening Visit 0a.FEV1 ≥ 70% predicted at baseline.
Positive immediate skin test for allergies to cat hair and reports asthma symptoms to cats, house dust mite and reports asthma symptoms to dust, or ragweed and reports asthma symptoms to ragweed (historical data documented within the last 5 years with our research group is acceptable).
Ability to tolerate a simulated MRI brain scanning session.
In the opinion of the investigator, capable and willing to grant written informed consent and cooperate with study procedures and requirements.
High-affinity TSPO-binding genotype. Mixed (high/low) binding-affinity genotype may be included at PIs discretion.

Exclusion

Current smoker (defined as more than 0.5 pack per week for the past 6 months and any smoking within two weeks of study procedures) or has a smoking history exceeding 5 pack years within the last 10 years
Currently receiving allergen immunotherapy
Use of psychotropic medication that might affect function of neurocircuitry implicated in the investigator's hypotheses at the discretion of the PI or Co-Investigator (Co-I)
Inability to hold medications detailed in the medication hold schedule
Needle phobia or claustrophobia
Major health problems such any of the following in the last 6 months: stroke/TIA, myocardial Infarction, stent placement, or acute coronary syndrome are definitively exclusionary. Decisions regarding other major health problems, such as autoimmune disease, history of carotid stenosis, heart disease, uncontrolled hypertension, lung diseases other than asthma, history of significant arrhythmias, etc. will be based upon the judgement of the PI/Co-I.
Use of biologic medication that might affect signaling pathways under investigation (at the discretion of the PI/Co-I)
Pre-existing chronic infectious disease
Scheduled use of non-selective beta-blockers prior to each study visit
Current use of beta-1 selective blockers (e.g., metoprolol, atenolol, acebutolol, betaxolol, esmolol, bisoprolo, and nebivolol)
Use of an investigational drug within 30 days of entering the study. This criterion will be reviewed on a case by case basis by the PI or Co-I to determine appropriate washout period. Appropriate wash out period may be greater than 30 days depending on the half-life of the investigational drug. Participants may be eligible for study participation after completing the washout period designated by the PI or Co-I (physician only).
Any MRI incompatibility as determined by most current MRI screening form
History of a diagnosed Bipolar Disorder, Schizophrenia, or Schizoaffective Disorder
History of serious head trauma or seizure disorder (can be included at the discretion of the PI or Co-I)
Unable, in the judgement of the investigator, to comply with directions and/or tolerate the procedures required for participation in this study
Pregnant or breast-feeding or has a planned pregnancy during the course of the study
Have corrected vision and are not able to wear contacts or see sufficiently well to read without glasses or contacts, as glasses will not fit in the PET/MR head coil
Any other medical condition or disease that would impact subject safety or data integrity in the opinion of the PIs
Ever intubated due to asthma and has not had a severe exacerbation requiring an ER visit or hospitalization in the past year.
Participants with well-controlled asthma at enrollment using ICS for their asthma will undergo a supervised step-down of therapy. This step-down aligns with the 2020 Focused Updates to the Management of Asthma Guidelines: Clinician Guide. Participants who undergo the supervised step-down will not proceed to V0a unless their asthma remains well-controlled for 6 weeks using PRN SABA only. Subjects will be monitored remotely during the supervised step-down. If the subject experiences any of the following during the supervised step-down, they will not be eligible to continue in the MAIA study:
Use of SABA \> 2 days a week for symptom relief (not for exercise-induced bronchoconstriction)
PEF \< 80% of baseline PEF for \> 2 days in a row
Use of systemic corticosteroids for asthma symptoms
ACT \< 20

What this trial measures

  • Presence of Neuroinflammation measured by TSPO observed via PET scanup to 9 days

    The investigators propose that, in subjects with asthma, provocation of airway inflammation activates microglia, indicative of a neuroinflammatory signal. The hypothesis is that microglial activation will occur following an inhaled allergen challenge, relative to pre-challenge. Activation of microglia will be measured using positron emission tomography (PET) with the radiotracer \[18F\]FEPPA, a tracer selective for translocator protein (TSPO) binding, which is elevated in activated microglia.