The primary aim of this study is to test whether type 2 diabetes interacts with estradiol on brain metabolism in vivo in humans. This will be accomplished by imaging brain metabolism using positron emission tomography before and after short-term administration of transdermal 17β-estradiol in 10 postmenopausal women with diabetes and 10 non-diabetic postmenopausal women.
Epidemiological studies suggest there may be an interaction between type 2 diabetes and estrogen in postmenopausal women, such that diabetes may interact with estrogen levels over time to increase risk for dementia. The mechanism for this effect is now known. However, animal research suggests that it may occur through estrogen's effects on cellular metabolism of glucose and ketone bodies. The primary aim of this study is to test whether type 2 diabetes interacts with estradiol on brain metabolism in vivo in humans. This will be accomplished by imaging brain metabolism using positron emission tomography before and after short-term administration of transdermal 17β-estradiol in 10 postmenopausal women with diabetes and 10 non-diabetic postmenopausal women.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
OTHER
Masking
NONE
Enrollment
12
transdermal 17β-estradiol patch
Wake Forest University Health Sciences
Winston-Salem, North Carolina, United States
Fluorodeoxyglucose (FDG) Positron Emission Tomography (PET)--Whole Brain
Brain metabolism will be measured using PET tracers to examine brain glucose uptake (FDG PET). PET imaging data are co-registered to T1 structural MRI data to conduct region-of-interest based analyses. Absolute global and regional uptake of FDG will be quantified.
Time frame: Baseline
FDG PET--Whole Brain
Brain metabolism will be measured using PET tracers to examine brain glucose uptake (FDG PET). PET imaging data are co-registered to T1 structural MRI data to conduct region-of-interest based analyses. Absolute global and regional uptake of FDG will be quantified.
Time frame: Week 8
Acetoacetate Uptake (AcAc) PET--Whole Brain
Brain metabolism will be measured using PET tracers to examine brain ketone body (acetoacetate) uptake (AcAc). PET imaging data are co-registered to T1 structural MRI data to conduct region-of-interest based analyses. Absolute global and regional uptake of AcAc tracers will be quantified.
Time frame: Baseline
AcAc PET--Whole Brain
Brain metabolism will be measured using PET tracers to examine brain ketone body (acetoacetate) uptake (AcAc). PET imaging data are co-registered to T1 structural MRI data to conduct region-of-interest based analyses. Absolute global and regional uptake of AcAc tracers will be quantified.
Time frame: Week 8
Change in Uptake of Glucose and Ketone Bodies in Whole Brain and Alzheimer's Disease-related Regions of Interest.
Brain metabolism will be measured using PET tracers to examine brain glucose uptake (FDG PET) and ketone body (acetoacetate) uptake (AcAc). PET imaging data are co-registered to T1 structural MRI data to conduct region-of-interest based analyses. Absolute global and regional uptake of FDG and AcAc tracers will be quantified, as well as uptake of AcAc relative to FDG to find potential regions of compensatory ketone use
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Time frame: Baseline and 8 weeks
Short-Term Memory Composite Score
A composite memory score was created by averaging z-scores for CVLT delayed recall, BVRT delayed recall, and prospective memory. A composite executive function score was created by averaging digit span forwards total correct, digit span backwards total correct, and both verbal fluency scores. Summed z-score ranging from -2 to 2 where higher score indicates better performance.
Time frame: Baseline and Week 8
Executive Function Composite Score
The California Verbal Learning Test (CVLT) is a word list recall task that can be used to test immediate and delayed verbal memory. Free recall after the short delay (immediately after learning lists) and long delay (25 minutes) are reported. Summed z-score ranging from -2 to 2 where higher score indicates better performance.
Time frame: Baseline and Week 8
California Verbal Learning Task (CVLT) Long Delay Free Recall
The CVLT is a word list recall task that can be used to test immediate and delayed verbal memory. Free recall after long delay (25 minutes). The minimum score is 0. The maximum score is 16 and a higher score represents better performance.
Time frame: Baseline and Week 8
CVLT Short Delay Free Recall
The CVLT is a word list recall task that can be used to test immediate and delayed verbal memory. Short delay free recall is immediately after learning lists. The minimum score is 0. The maximum score is 16 and a higher score represents better performance.
Time frame: Baseline and Week 8
Benton Visual Retention Task (BVRT) Total Score
The BVRT tests figural memory by testing memory for a line drawing. The minimum score is 0. The scoring used is total correct, the maximum score is 10, and a higher score represents better performance. The total score is reported.
Time frame: Baseline and Week 8
Prospective Memory
The Prospective Memory test is a test of everyday memory where participants are given instructions for 3 tasks that will occur later on during the testing session. The minimum score is 0. The maximum score is 12 points, a higher score represents better performance, and the total score is reported
Time frame: Baseline and Week 8
Verbal Fluency (Letters)
Participants were given a letter and asked to say aloud as many words as they could think of beginning with that letter. The three letters were F, A, and S, and the participant had one minute per letter to list words. The total score reported is the sum of the correct words generated for all three letters. Although there is no set maximum score, based on published data, it was anticipated that scores could range from 1 to no more than 120. A higher value reflects better performance.
Time frame: Baseline and Week 8
Verbal Fluency Score (Fruits and Vegetables)
Participants were given one minute to say aloud as many fruits as possible and one minute to list as many vegetables as possible. The total score reported is the sum of all correct fruits and vegetables listed. Although there is no set maximum score, it was anticipated that scores could range from 0 to no more than 60. A higher value reflects better performance.
Time frame: Baseline and Week 8
Digit Span Forward Total Correct
Participants listened to a sequence of two to nine numbers and were asked to repeat each sequence back to the tester in the same order the numbers were presented. The outcome measure reported here is the total number of correct responses (range of scores 0-9). Higher scores reflect better performance.
Time frame: Baseline and Week 8
Digit Span Backward Total Correct
Participants listened to a sequence of two to nine numbers and were asked to repeat each sequence back to the tester in reverse order. The outcome measure reported here is the longest span of numbers recalled (range of scores 0-9). Higher scores reflect better performance.
Time frame: Baseline and Week 8
Finger Tapping Score--Dominant Hand
The Finger Tapping test assesses fine motor speed by asking participants to tap a button as many times as possible. Seven trials were administered. The highest and lowest scores were dropped, and the reported score is the average of the remaining 5 trials. Results for the dominant hand are reported here. There is no set maximum score. However, published averages for women in this age range suggest that a value over 57 would be highly unusual. A higher value (more taps) is better performance.
Time frame: Baseline and Week 8
Finger Tapping Score--Non-Dominant Hand
The Finger Tapping test assesses fine motor speed by asking participants to tap a button as many times as possible. Seven trials were administered. The highest and lowest scores were dropped, and the reported score is the average of the remaining 5 trials. Results for the non-dominant hand are reported here. There is no set maximum score. However, published averages for women in this age range suggest that a value over 57 would be highly unusual. A higher value (more taps) is better performance.
Time frame: Baseline and Week 8
Card Rotations Test Score
The Card Rotations Test is used to assess the ability to mentally rotate figures in space. The test has two parts, each of which last 3 minutes. During each part, the participant is given a sheet of paper with 10 simple geometric figures. Next to each figure is a row of 8 similar figures. Participants are asked to mark whether each of the figures in the row is the same or different than the first figure in the row. The score reported is the number of correct responses. The minimum score is 0. The maximum possible score is 160 and a higher score reflects better performance.
Time frame: Baseline and Week 8
Change in Short-term Memory and Executive Function Composite Scores.
A battery of cognitive tasks will be administered before and after estrogen administration. Composite z-scores will be calculated by calculating a z-score for each cognitive task and summing z-scores from -5 (low) to 5 (high) for the tasks designated as short-term memory and executive function.Higher scores denotes better outcomes.
Time frame: Baseline and 8 weeks