Cerebrovascular Circulation, Magnetic Resonance Imaging
Conditions
Keywords
Magnetic Resonance Imaging, Brain Blood Flow, Lower Body Negative Pressure, Carbon Dioxide
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.
Interventions
DEVICEMRI
Participants will undergo an MRI scan while performing breathing and a simulated postural change task.
DRUGPrazosin
A dose of prazosin will be administered based on body weight.
DRUGPlacebo
Oral placebo
Sponsors
University of Wisconsin, Madison
National Institute of Neurological Disorders and Stroke (NINDS)
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
55 Years to 69 Years
Healthy volunteers
Yes
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).
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in blood flow | Two study visits, up to 240 minutes | The change in intracranial blood flow during breathing and simulated postural change tasks will be measured with MRI |
| Change in blood velocity | Two study visits, up to 240 minutes | The change in blood velocity during breathing and simulated postural change tasks will be measured with MRI. |
Countries
United States
Contacts
CONTACTAnna Howery
PRINCIPAL_INVESTIGATORJill Barnes, PhD
UW Madison
Outcome results
None listed