Brain Blood Vessel Responses to Changes in Blood Flow

NCT ID: NCT06629077

Last Updated: 2026-01-22

Basic Information

• Recruitment Status: NOT_YET_RECRUITING
• Clinical Phase: PHASE2
• Total Enrollment: 36 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2026-02-28
• Study Completion Date: 2027-01-31

Brief Summary

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

Detailed 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.

Conditions

Magnetic Resonance Imaging; Cerebrovascular Circulation

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: NONE

Study Groups

Middle-Aged Adults

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

Group Type: EXPERIMENTAL

MRI

Intervention Type: DEVICE

Participants will undergo an MRI scan while performing breathing and a simulated postural change task.

Prazosin

Intervention Type: DRUG

A dose of prazosin will be administered based on body weight.

Placebo

Intervention Type: DRUG

Oral placebo

Interventions

MRI

Participants will undergo an MRI scan while performing breathing and a simulated postural change task.

Intervention Type: DEVICE

Prazosin

A dose of prazosin will be administered based on body weight.

Intervention Type: DRUG

Placebo

Oral placebo

Intervention Type: DRUG

Eligibility Criteria

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).

• Minimum Eligible Age: 55 Years
• Maximum Eligible Age: 69 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

National Institute of Neurological Disorders and Stroke (NINDS)

NIH

Sponsor Role: collaborator

University of Wisconsin, Madison

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Jill Barnes, PhD

Role: PRINCIPAL_INVESTIGATOR

UW Madison

Locations

University of Wisconsin

Madison, Wisconsin, United States

Countries

United States

Central Contacts

Anna Howery

Role: CONTACT

ahowery@wisc.edu

608-262-9572

Facility Contacts

Anna J Howery, MS

Role: primary

barneslab@education.wisc.edu

608-262-9572

Other Identifiers

2024-0377

Identifier Type: -

Identifier Source: org_study_id

1RF1NS117746-01

Identifier Type: NIH

Identifier Source: secondary_id

View Link

A176000

Identifier Type: OTHER

Identifier Source: secondary_id

EDUC/KINESIOLOGY

Identifier Type: OTHER

Identifier Source: secondary_id

Protocol Version7/29/2025

Identifier Type: OTHER

Identifier Source: secondary_id