How brain blood vessels respond to changes in blood flow

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This Phase 2 interventional protocol uses MRI to measure global and regional cerebral blood flow while participants undergo two controlled physiological challenges: a simulated postural change using lower body negative pressure and brief inhalation of elevated carbon dioxide. Participants who meet inclusion criteria will receive either the alpha-1 blocker prazosin or placebo to probe the role of sympathetic signaling in cerebrovascular control. MRI scans will be performed before, during, and after each challenge to quantify cerebrovascular reactivity and compare responses by drug condition. The study aims to identify alterations in blood flow regulation that could explain accelerated declines in cerebral perfusion with age.

Why it matters

Who can join: the full rules

Inclusion Criteria:

* Between the ages of 55-69 years
* Have a BMI less than or equal to 34.5 kg/m2
* Nonsmoker
* are less than 72 in (182.88 cm) height
* Females must be postmenopausal

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%
* Major neurologic disorders other than dementia (e.g., MS, ALS, brain surgery, etc.)
* Current or recent (\<1 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 it's running

• 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

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

• How younger adults' brain blood vessels respond to changes in blood flow

  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.

  Recruiting Phase 2 University of Wisconsin, Madison · Madison, Wisconsin · NCT06629090

• Ketogenic Diet and Alcohol Intoxication: Can ketosis affect brain function and alcohol response

  This study tests whether a 4‑week ketogenic diet changes how the brain works and how the body handles alcohol in adults who drink regularly.

  Recruiting University of Pennsylvania · Philadelphia, Pennsylvania · NCT07602270

• How short high-oxygen exposures affect brain blood flow during mechanical ventilation

  We will test whether brief, controlled increases in ventilator oxygen change brain blood flow in adults who are intubated and on mechanical ventilation in the ICU.

  Recruiting Erasme University Hospital · Brussels · NCT07377162

• Using MRI to speed diagnosis and care for adults with acute stroke in the emergency room

  We will test whether a streamlined MRI protocol helps doctors diagnose and treat adults with acute stroke faster in the emergency department.

  Recruiting Tanta University · Tanta, El-Gharbia · NCT07138768

• Following memory decline in Alzheimer disease

  This project will use 7T MRI, EEG, blood and stool samples, and memory tests to see if they can track memory decline in people over 55 with Alzheimer's disease or mild cognitive impairment.

  Recruiting Norwegian University of Science and Technology · Trondheim, Trønderlag · NCT07118137

• Predicting recovery after thrombolysis and thrombectomy using brain scan scores

  This project will see if combining standard brain imaging scores can predict 90-day recovery and vessel reopening in adults who had an acute ischemic stroke treated with clot-busting medicine and clot removal.

  Recruiting Centre Hospitalier de Gonesse · Gonesse · NCT07069452

How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.