Aging, Healthy
Conditions
Keywords
Magnetic Resonance Imaging, Transcranial Doppler Ultrasound, Hypercapnia
Brief summary
Baseline cerebral blood flow through the middle cerebral artery (MCA) and cerebral vasodilator response of the MCA to inhaled carbon dioxide (CO2) will be measured in young women, young men, older women, and older men using Magnetic Resonance (MR) imaging and transcranial Doppler ultrasound (TCD). Data collection techniques will be compared.
Detailed description
The investigators have recently shown that cerebral blood flow responses to chemical stimuli are reduced in healthy older adults. The investigators also have preliminary data suggesting that sex differences in cerebrovascular regulation exist. The overall goal of this application is to extend on the investigators previous studies by employing advanced neuroimaging techniques to enhance the investigators understanding of neurovascular coupling in healthy aging. This study will collect clinically significant data with implications for the future risk of cognitive decline and Alzheimer's disease. The research aims are: 1. To determine the effect of age and sex on baseline cerebral blood flow through the middle cerebral artery (MCA). 2. To determine the effect of age and sex on cerebral vasodilator responses. 3. To determine if the cerebrovascular responses measured by transcranial Doppler ultrasound (TCD) are associated with the cerebrovascular responses measured by Magnetic Resonance (MR) imaging.
Interventions
DEVICEMRI
Participants will undergo a MRI scan while two stepwise CO2 elevations are applied to the participant by adding fractional concentration of inspired CO2 (FICO2) at 4% and 6% each time. The end tidal CO2 (PetCO2) will be elevated and maintained constant for a few minutes at each target level. Breath-by-breath changes in respiratory rate and PetCO2 will be measured.
DEVICETCD
Participants will undergo a TCD scan while two stepwise CO2 elevations are applied to the participant by adding fractional concentration of inspired CO2 (FICO2) at 4% and 6% each time. The end tidal CO2 (PetCO2) will be elevated and maintained constant for a few minutes at each target level. Breath-by-breath changes in respiratory and PetCO2 will be measured.
Sponsors
University of Wisconsin, Madison
Study design
Observational model
CASE_CONTROL
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
20 Years to 64 Years
Healthy volunteers
Yes
Inclusion criteria
* Between 20-34 or 50-69 years * Body mass index \<34 kg/m2
Exclusion criteria
* Current smoker * History or evidence of: hepatic disease, renal disease, hematological disease, peripheral vascular disease, stroke/neurovascular disease, diabetes, hypertension * Part of a vulnerable population (e.g. pregnant women, prisoner, individuals lacking capacity to consent, etc.) * Older females only: subject is not post-menopausal
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Middle Cerebral Artery Blood Flow Measurement | 75 minutes | Utilize the TCD and MR imaging to measure middle cerebral artery blood flow in the brain while the participant is at rest. |
| Middle Cerebral Artery Blood Flow Reactivity to Hypercapnia | 75 minutes | Utilize the TCD and MR imaging to measure middle cerebral artery blood flow reactivity to hypercapnic gas. |
Countries
United States
Outcome results
None listed