Brain Blood Vessel Responses to Changes in Blood Flow

University of Wisconsin (UW)

Status and phase: Not yet enrolling; Phase 2

Conditions: Cerebrovascular Circulation; Magnetic Resonance Imaging

Treatments: Drug: Placebo; Drug: Prazosin; Device: MRI

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT06629077

1RF1NS117746-01 (U.S. NIH Grant/Contract)

Protocol Version7/29/2025 (Other Identifier)

A176000 (Other Identifier)

2024-0377

EDUC/KINESIOLOGY (Other Identifier)

Details and patient eligibility

About

Brain blood flow will be measured during a simulated postural change test and while breathing increased levels of carbon dioxide using magnetic resonance imaging.

Full description

Global cerebral blood flow (CBF) decreases with advancing age; however, some adults have accelerated declines in CBF, placing them at a greater risk of cognitive impairment. However, there is a lack of human studies that investigate the cause or consequence of altered blood flow regulation in the brain. This study will systematically address this gap in knowledge by examining cerebrovascular control in adults during acute physiological challenges (simulated postural change test and breathing increased carbon dioxide) that stimulate a change in CBF.

Enrollment: 36 estimated patients

Sex: All

Ages: 55 to 69 years old

Volunteers: Accepts Healthy Volunteers

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).

Trial design

Primary purpose: Basic Science

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

---

36 participants in 1 patient group

Middle-Aged Adults

Experimental group

Description:

Middle-Aged Adults between 55-69 years of age.

Treatment:

Device: MRI

Drug: Prazosin

Drug: Placebo