How younger adults' brain blood vessels respond to changes in blood flow
Cerebrovascular Responses to Acute Hypoperfusion
We will use MRI to test how brain blood flow changes during a simulated postural shift and while breathing more carbon dioxide in healthy adults aged 20–40, and whether prazosin changes those responses.
Quick facts
| Phase | Phase 2 |
|---|---|
| Study type | Interventional |
| Enrollment | 36 (estimated) |
| Ages | 20 Years to 40 Years |
| Sex | All |
| Sponsor | University of Wisconsin, Madison Academic / other |
| Locations | 1 site (Madison, Wisconsin) |
| Trial ID | NCT06629090 on ClinicalTrials.gov |
What this trial studies
This Phase 2 interventional protocol uses MRI to measure global cerebral blood flow in adults aged 20–40 during two controlled physiological challenges: a simulated postural change (via lower body negative pressure) and controlled increases in inhaled carbon dioxide. Participants will receive prazosin or placebo and undergo MRI scans while investigators record cerebrovascular responses and blood flow regulation. The trial excludes people with major cardiovascular, cerebrovascular, neurologic, psychiatric, hepatic, or renal disease, as well as smokers and those outside the specified BMI and height limits. Data will compare responses with and without alpha‑1 blockade to clarify mechanisms of cerebrovascular control that could relate to later cognitive risk.
Who should consider this trial
Good fit: Healthy adults 20–40 years old who are nonsmokers, under 72 inches tall, with BMI ≤34.5 kg/m2 and without major cardiovascular, cerebrovascular, neurologic, psychiatric, hepatic, renal disease, or uncontrolled diabetes are the intended participants.
Not a fit: People with mild cognitive impairment or Alzheimer's, significant cardiovascular or cerebrovascular disease, uncontrolled hypertension, active major psychiatric/addictive disorders, smokers, severe untreated sleep apnea, or those outside the age/height/BMI criteria are unlikely to benefit or be eligible.
Why it matters
Potential benefit: If successful, the results could help identify early problems in blood flow regulation and guide strategies to prevent or delay cognitive decline.
How similar studies have performed: Prior human work has characterized cerebrovascular responses to CO2 and orthostatic stress, but combining MRI with pharmacologic alpha‑1 blockade in younger adults is relatively novel and has limited precedent.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: * Between the ages of 20-40 years * Have a BMI ≤34.5 kg/m2 * are less than 72 in (182.88 cm) height * Nonsmoker Exclusion Criteria: * Diagnosis of Mild Cognitive Impairment (MCI) or Alzheimer's disease (AD) * History or evidence of hepatic disease, hematological disease, or peripheral vascular disease; severe kidney injury requiring hemodialysis * History of cardiovascular disease including: severe congestive heart failure, coronary artery disease, ischemic heart disease (stents, coronary artery bypass grafts) and tachycardia * Uncontrolled hypertension * History of clinically significant ischemic or hemorrhagic stroke, or significant cerebrovascular disease * Severe untreated obstructive sleep apnea * History of diabetes with HbA1c greater than 9.5 percent * Major neurologic disorders other than dementia (e.g., MS, ALS, brain surgery, etc.) * Current or recent (less than1 year) major psychiatric condition (Axis I) or addictive disorders * Significant surgical history * Other significant medical conditions at investigators' discretion * Contraindications to MRI * Prescribed medications that interfere with prazosin * Lactose allergy * lower body will not fit in lower body negative pressure (LBNP) chamber (regardless of overall height and BMI)
Where this trial is running
Madison, Wisconsin
- University of Wisconsin — Madison, Wisconsin, United States (Recruiting)
Study contacts
- Principal investigator: Jill Barnes, PhD — UW Madison
- Study coordinator: Anna Howery
- Email: ahowery@wisc.edu
- Phone: 608-262-9572
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.