NAD Therapy for Improving Memory and Brain Blood Flow in Older Adults With Mild Cognitive Impairment
Phase: PHASE1
Conditions: Mild Cognitive Impairment
Sponsor: University of Delaware

 
1 
Title: NAD therapy for improving memory and brain blood flow in older adults with mild cognitive 
impairment 
 
NCT Number: NCT03482167 
 
Document Date: 11/14/2024 
 
 
 

 
2 
 
HUMAN SUBJECTS PROTOCOL  
University of Delaware 
 
NAD therapy for improving memory and brain blood flow in older adults with mild cognitive 
impairment 
 
  
 
Principal Investigator:  
Name:   
 
 
Christopher R. Martens, Ph.D. 
Department/Center:  
 
Kinesiology & Applied Physiology 
Contact Phone Number:  
(302) 831-7270 
Email Address:   
 
cmartens@udel.edu 
 
Investigator Assurance: 
By submitting this protocol, I acknowledge that this project will be conducted in strict accordance with the 
procedures described. I will not make any modifications to this protocol without prior approval by the IRB. 
Should any unanticipated problems involving risk to subjects occur during this project, including breaches 
of guaranteed confidentiality or departures from any procedures specified in approved study documents, I 
will report such events to the Chair, Institutional Review Board immediately.   
 
1.  Is this project externally funded? X YES □ NO 
 
National Institute on Aging (K01-AG054731) 
 
2. Research Site(s) 
 
X University of Delaware 
□ Other (please list external study sites) 
 
 
3.  Project Staff 
Please list all personnel, including students, who will be working with human subjects on this protocol 
(insert additional rows as needed): 
 
[REDACTED] 
 
  
4.  Special Populations 
Research with any other vulnerable population (e.g. cognitively impaired, economically 
disadvantaged, etc.)? 
 
The subjects in this study must have cognitive function scores that are consistent with amnestic mild 
cognitive impairment (aMCI), which is defined by a lack of dementia and mild impairment in memory with 
or without impairments to other domains of cognitive function.  Given the mild impairment of the 
prospective subjects, a legally authorized representative (LAR) is not required to obtain informed consent.   
The decisional capacity of study subjects and their ability to provide informed consent on their own will be 
evaluated at the time of initial consent and confirmed at each visit to ensure continued ability to provide 
consent.  The following questions will be used to assess whether or not subjects can consent for 
themselves: 
1. Describe in your own words the purpose of this study? 
2. What are you being asked to do today? 
3. What are the side effects/risks of being in the study? 
4. Is this voluntary? 
5. What do you do if you have questions or possible side effects? 

 
3 
Individuals who cannot answer these questions will be asked to take MMSE test of dementia (described 
below) before being allowed to continue in the study.  Any subject who lacks the ability to provide consent 
and/or is determined to have developed dementia at any point during the study will be withdrawn from the 
study and will be referred to their Primary Care Practitioner (PCP). 
 
5.  RESEARCH ABSTRACT Please provide a brief description in LAY language (understandable to an 
8th grade student) of the aims of this project. 
 
Increased blood pressure and stiffening of the large elastic arteries (i.e., the aorta and carotid arteries) 
occurs with aging and likely contributes to memory loss and risk of Alzheimer’s disease (AD) by impacting 
blood vessels within the brain1–4 . Healthy lifestyle strategies, including regular calorie restriction (CR), 
have been shown to improve blood vessel function in the brain and slow the progression of AD5; however, 
long-term adherence to CR is very difficult and may lead to unsafe weight loss in normal weight older 
adults6.  The purpose of this study is to determine whether a dietary supplement that mimics the 
beneficial effects of CR (nicotinamide riboside; “NR”) restores memory and other cognitive functions (aim 
1), reduces arterial stiffness and blood pressure and improves arterial function within the brain (aim 2), 
and improves neurovascular coupling and neuronal activation (aim 3) in patients with “amnestic” mild 
cognitive impairment (aMCI), a condition associated with impaired memory increased risk for AD.  To 
accomplish these aims, we will conduct a randomized, double-blind, placebo-controlled clinical trial of NR 
supplementation vs. placebo. This project has the potential to identify a novel, safe and cost-effective 
strategy for decreasing age-related memory loss and will help us understand how impaired blood vessel 
function may contribute to risk for AD.                         
6.  PROCEDURES  
Study Design. A randomized, placebo-controlled, double blind, parallel group clinical trial will be 
conducted to assess the efficacy of 12-weeks of oral nicotinamide riboside capsules (NR; 500mg, 2x/day, 
trade name NIAGEN®, ChromaDex Inc., Irvine CA) for improving memory and other cognitive functions in 
adults with cognitive scores indicative of aMCI.  Secondary outcomes will include measures of 
vascular/cerebrovascular and neuronal function and brain structure. This design and duration has been 
used previously to study the efficacy of interventions for improving vascular function in older adults7. 
Study participants and investigators involved in data acquisition and/or analysis will be blinded to 
treatment condition. All primary and secondary outcome measures will be made at baseline and after 12 
weeks of treatment.  Visits will take place in the Neurovascular Aging Laboratory (NOVA Lab) on the 
STAR Research Campus at the University of Delaware, with the exception of MRI measures which will be 
made at the UD Center for Biomedical Brain Imaging (CBBI).  Details pertaining to the safety and toxicity 
of the intervention and rationale for the proposed frequency and duration are presented at the end of this 
section. 

 
4 
DETAILED OVERVIEW OF STUDY VISITS 
PRE-SCREENING PHONE SCREENING 
Prior to scheduling Visit 1 informed consent & screening, a member of the research team will complete a 
brief phone screen and will ask the subject the COVID-19 questionnaire in order to ascertain specific 
information regarding possible hospitalization as a result of COVID-19 diagnoses, and vaccination. If 
subject acknowledges any hospitalization as a result of COVID-19, the subject will be excluded and will 
not be permitted to enroll in the current study. If the subject discloses specific information as it relates to 
receiving the COVID-19 vaccine, the subject will not be permitted to participate in any data collection 
procedures until one week following any COVID-19 vaccination. These questions will also be asked 
during the week 10 phone check-in before scheduling week 12 visits. 
VISIT 1: INFORMED CONSENT & SCREENING (2.0 hours) 
Subjects will be instructed to fast for ≥ 12 hours before testing 
• 
Informed Consent for participation in the clinical trial will be obtained by a trained member of the 
research team.  All procedures and aspects related to the study including any potential risks will be 
Brief Overview of Study Visits 
 
 
 
Week 
Visit # 
Duration 
Location 
Visit Description 
Blood 
Screening  
Week -1 
Screening for MCI will occur under a separate protocol and eligible participants will 
be brought in for informed consent and study-specific screening 
Visit 1 
2 hours 
Virtual*  
Informed Consent   
& General Screening 
 
 Visit 1.1 
30 
minutes 
NOVA Lab 
or LabCorp 
Screening Blood 
Draw 
74 mL (~5.0 TBL) 
Randomization 
Group A: NR or Group B: Placebo 
Baseline 
Testing 
Week 0 
Visit 2 
3 hours 
NOVA Lab 
Vascular Testing 
--- 
Visit 3 
1.5 hours 
 Virtual* 
Cognitive Testing 
--- 
Visit 4 
2 hours 
CBBI 
Neuronal Testing & 
Receive Capsules 
--- 
Intervention 
Period 
Week 2 
10 min Phone Check-In 
--- 
Week 4 
Visit 5 
0.5 hours 
 Virtual* 
Zoom Check-In 
--- 
Week 6 
10 min Phone Check-In 
--- 
Week 8 
Visit 6 
0.5 hours 
 Virtual* 
Zoom Check-In 
--- 
Week 10 
10 min Phone Check-In 
--- 
Follow-Up 
Testing 
Week 12 
Visit 7 
3 hours 
NOVA Lab 
Vascular Testing 
60 mL (~4.0 TBL) 
Visit 8 
1.5 hours 
 Virtual* 
Cognitive Testing 
--- 
Visit 9 
2 hours 
CBBI 
Neuronal Testing 
--- 
 
Total Time 
16 hours 
 
Total Blood 
134 mL (~9.0 TBL) 
* Virtual visits may be completed in person at the Neurovascular Aging Laboratory if the participant does 
not have access to a computer with video conferencing capabilities or upon the participant’s request. 

 
5 
described to the subject.  The investigator will read the informed consent form to the subject and will 
answer any questions that the subject may have prior to obtaining the subject’s written consent.  As 
documentation of the informed consent, the subject and the investigator performing the consent will 
sign the consent document and a copy of the signed consent form will be given to the subject.  
Alternatively, the consent may also be performed online via a private video conference and using the 
eConsent framework in REDCap. The video conferencing software is HIPAA-compliant and each 
scheduled online meeting will be secured with private meeting access controls, password protection, 
and end-to-end encryption so data in transit cannot be intercepted. The ability to provide informed 
consent will be monitored by the research team throughout the trial.  In addition to obtaining written 
informed consent, all experimental procedures will be re-explained to the subjects at the time that 
they are performed, and verbal consent will be obtained. 
• 
Family history questionnaire:  A family history questionnaire will be used to obtain information 
regarding family history of cardiovascular diseases, cancer, diabetes, and Alzheimer’s disease in 
order to determine if family history may account for any differences in the efficacy of NR 
supplementation in improving cerebrovascular, cognitive and/or neuronal functions. This 
questionnaire can be completed in-person or online via REDCap. 
• 
Patient-Reported Outcomes (PROMIS) Measures. Subjects will answer a brief battery of self-
guided questionnaires (administered using an iPad, or online via REDCap) to determine their own 
perception of their health and well-being.  Outcome measures will include: fatigue, pain, physical 
function, sleep disturbance, anxiety, depression, alcohol use, and social abilities. 
• 
Menstrual History Questionnaire. A menstrual history questionnaire will be administered to all 
female subjects to confirm postmenopausal status. This questionnaire can be completed in-person or 
online via REDCap.  
• 
Medical History. We will ask subjects about their medical history to ensure that subjects meet the 
inclusion criteria and do not have an underlying condition that would disqualify them based on stated 
exclusion criteria.  This can be completed in-person or online via REDCap. This information will be 
shared with the NMPCC Nurse Practitioner. 
• 
COVID-19 Questionnaire. We will ask subjects about their history with COVID-19, if they were ever 
hospitalized, experienced symptoms, and details regarding vaccination.  
• 
Blood pressure and resting heart rate.  Blood pressure will be measured from the non-dominant 
arm in the seated position after at least 10 minutes of quiet rest using a semi-automated blood 
pressure device. Repeat measurements will be made (with 2 minutes of quiet rest between 
recordings) until 3 blood pressure values obtained are within 5 mmHg of one another.  These values 
will be averaged to determine resting systolic and diastolic blood pressure and pulse pressure.  
 
 
VISIT 1.1: Screening Blood Draw (0.5 hours) 
• 
Baseline Blood Sampling. A total of 74 mL (5.0 tablespoons) of blood will be drawn by the research 
nurse or certified research team member. Some of the blood will be sent to LabCorp for analysis of 
clinical parameters and the rest will be processed in our own laboratory for determination of APOE4 
genotype and isolation of peripheral blood mononuclear cells (PBMC’s) (see below).  All clinical 
parameters from LabCorp will be reviewed by a Nurse Practitioner at the NMPCC along with the 
subject’s medical history form.  Alternatively, if participants choose to complete all screening 
remotely, the option is available to the participant to have baseline blood work and urine collected at 
local LabCorp patient service centers using our research requisition form. This will be billed directly to 
the lab and will not go through the subject’s insurance or cost anything out of pocket. In the event of a 
clinically significant abnormality, as determined by the Nurse Practitioner, the NMPCC will refer the 
subject to their PCP for follow-up and that participant will be excluded from the research study. 
Participants will sign a HIPAA authorization in the informed consent form that includes permission for 
sharing of patient protected health information with the research team. Blood samples will be 

 
6 
obtained to assess safety to the intervention and as control measures for primary outcomes. If 
enough blood cannot be obtained during a blood draw visit, the participant may be asked to repeat 
the blood draw on a separate day (e.g., due to missed stick, insufficient volume, or laboratory error). If 
a subject is accepted into the study, these clinical labs will also serve as their baseline sample.  
Screening markers will consist of: 
o 
APOE Genotype (Visit 1 only). Individuals with the E4 variant of the Apolipoprotein E 
(APOE) gene are at increased risk of developing late-onset Alzheimer’s disease (AD)8.  
Because the APOE gene is also involved in the regulation of lipid metabolism, specific 
variants of this gene have been associated with increased risk for cardiovascular diseases.  
To ensure that APOE genotype does not confound any of our primary cardiovascular 
outcomes, and to ensure that subjects carrying the E4 variant are evenly distributed between 
the active and placebo arm of the study, we will isolate each subject’s DNA and will 
determine their APOE genotype using PCR, prior to randomization.  The results of this test 
will be made available to subjects, upon request, with a disclaimer that the results were 
generated in a non CLIA-certified laboratory for research purposes only. 
o 
General blood chemistry. Includes a comprehensive metabolic profile, lipid profile, 
complete blood count (CBC) with differential, prothrombin time and partial thromboplastin 
time.  
o 
Kidney and liver function.  Because kidney and liver dysfunction could influence the 
metabolism and bioavailability of NR, markers of liver function (ALB, ALT, AST, ALP, total 
bilirubin (TBILI) and kidney function (blood urea nitrogen (BUN), creatinine (CRE), sodium, 
and potassium) will be measured prior to subject randomization. 
o 
Vitamin B6, B12 and Folate. Known to influence memory. 
o 
Peripheral Blood Mononuclear Cells. Required for assessment of NAD+ related 
metabolites and mitochondrial respiration. 
o 
COVID Antibody. Because recent COVID-19 infection has been associated with increased 
incidence of stroke and other cardiovascular complications, we will test for the presence of 
COVID-19 antibodies at baseline and at the end of the study and will perform a sensitivity 
analysis at the end of the study to determine the potential confounding effect of previous 
COVID-19 infection on all study outcomes. This test will only be performed in individuals not 
vaccinated against the SARS-CoV2 virus. 
• 
Baseline Urine Sampling. A midstream urine specimen will be collected into a clear container during 
the baseline laboratory visit, or at their local LabCorp patient service center and a complete urinalysis 
will be conducted.  Urine samples will be collected after the early morning void has been discarded.  
Urinalysis will be repeated after the 12-week intervention period. 
• 
Middle Cerebral Artery Screening: A research team member will use a transcranial doppler 
ultrasound probe to examine the temporal window for screening of a visible middle cerebral artery. 
This is done during the screening visit to simplify the preparation of Visits 2 & 7. The results of this 
screening test will not impact eligibility for this study. 
RANDOMIZATION (will occur after VISIT 1.1) 
• 
Randomization Procedures. Subjects who qualify for the study based on screening assessments 
will be randomly assigned by the study coordinator to receive either treatment A or treatment B.  The 
identity of each treatment (i.e., NR or placebo) will be blinded by the manufacturer (ChromaDex, Inc.) 
and the blinding code will be sent to a member of the PI’s department (Megan Wenner) who is 
unaffiliated with this study.  Dr. Wenner will enter the blinding code in a secure REDCap form that will 
remain hidden from the rest of the study team.  The PI will be given a separate login ID and password 
to access this REDCap form and determine the assigned treatment condition of a subject in the event 
of an emergency (described below under serious adverse events).  A blocked randomization scheme 
will be uploaded into REDCap by the biostatistician with block size (b) resulting in an imbalance of no 
more than 2 subjects (b/2) between group assignments.  To address potential imbalance between 
key biological variables including sex (male vs. female) and APOEε4 status (carriers vs. non-carriers), 

 
7 
the blocked randomization scheme will be stratified such that participants within each strata will be 
block randomized to either placebo or NR. 
Study Restrictions. All experimental visits will be conducted under overnight fasted conditions (no meal 
within ~12 hours of testing) with the exception of cognitive function and MRI sessions. Participants will be 
asked to discontinue use of any vitamin B3-containing supplements (i.e., nicotinamide, niacin, nicotinic 
acid, nicotinamide riboside, nicotinamide mononucleotide) 2 weeks prior to and throughout participation in 
the study. Subjects will be asked to refrain from non-prescription medications for 48 hours; alcohol and 
exercise for 24 hours, caffeine for 12 hours prior to all study visits as these are factors known to modulate 
vascular function as well as circulating biomarkers of interest.  If subjects receive the COVID-19 vaccine, 
they will not perform any experimental visit until at least one week following vaccination.  
PRIMARY & SECONDARY OUTCOMES 
All experimental visits will be performed in the PI’s Laboratory unless otherwise indicated.  An optional 
snack will be offered following all experimental visits in which fasting is required. 
VISIT 2 & 7: VASCULAR FUNCTION (NOVA Lab; 3 hours each) 
Subjects will be instructed to refrain from taking over the counter medications for 48 hours, vigorous 
aerobic exercise and alcohol for 24 hours, and to fast (no food, supplements or caffeine) for ≥12 hours 
before testing.   
• 
Height and body mass: Subject height and body mass will be measured using a physician’s scale. 
• 
Arterial Stiffness Assessments 
o 
Pulse Wave Velocity (PWV).  Carotid-to-femoral PWV (a measure of aortic stiffness) will be 
assessed non-invasively using sequential transcutaneous tonometry of the carotid and 
femoral arteries (SphygmoCor, AtCor Medical).  The time delay (transit time) between the 
foot of pressure waves obtained at each location will be determined using the R-wave of an 
ECG recording taken during the tonometry procedure as a timing reference.  PWV will be 
calculated as the distance between measurement sites divided by the transit time of the 
arterial pulse wave. 
o 
Pulse Wave Analysis (PWA).  Central hemodynamic properties, including the central pulse 
pressure (PP), augmentation pressure (AP) and augmentation index (AI) will be derived from 
the radial artery pulse wave using applanation tonometry. 
o 
Carotid Artery Compliance. Carotid compliance (a measure of large artery distensibility) will 
be measured non-invasively using high-resolution ultrasonography of one carotid artery and 
applanation tonometry of the opposite carotid artery (SphygmoCor, AtCor Medical).  
Compliance will be calculated as the change in carotid diameter for a given change in 
pressure as described previously by our laboratory. 
 
• 
Cerebrovascular Function Assessments 
o 
Cerebrovascular Reactivity will be measured by assessing the change (from baseline) in 
mean blood flow velocity (MFV) of the middle cerebral artery (ΔMFVMCA) in response to 
increases or decreases in the end-tidal (end-expiratory) partial pressure of carbon dioxide 
(PETCO2), which evokes a vasodilatory or vasoconstriction response in the cerebral arteries, 
respectively.  MFV will be measured using a 2-MHz Transcranial Doppler (TCD) ultrasound 
probe positioned over the temporal window as previously described in the literature9,10. The 
control of PETCO2 will be achieved using computer assisted gas blender (RespirAct, Thornhill 
Medical) that automatically adjusts the composition and flow rate of inspired O2 and CO2 in 
order to manipulate PETCO2 independent of a subject’s ventilation and breathing pattern.  
Following a baseline recording at normocapnia (simulated room air) at the subjects preferred 
breathing rate, a second baseline will be recorded at a controlled breathing rate of 20 
breaths/minute (to improve PETCO2 targeting).  The vasodilatory stimulus will consist of 3-
minutes of hypercapnia in which PETCO2 is abruptly increased to +9mmHg above the 

 
8 
subject’s baseline.  Subjects will then return to their baseline PETCO2 for 2 minutes, followed 
by a -9mmHg decrease in PETCO2 to initiate vasoconstriction.   Subjects will maintain the 
paced breathing pattern throughout the protocol.  End-tidal partial pressure of oxygen will be 
held constant throughout the protocol.  Breath-by-breath end-tidal CO2 and O2 (ETCO2) will 
be continuously monitored to confirm successful end-tidal targeting and beat-by-beat arterial 
blood pressure will be continuously recorded using a Finapres (Finapres Medical Systems), 
to control for changes in mean arterial pressure (MAP), which may influence cerebral 
perfusion. This test will only be performed on individuals with a suitable temporal window, as 
determined during screening. 
o 
Pulsatility Index (PI). Pulsatile blood flow velocity within the cerebral arteries is positively 
associated with large elastic artery stiffness and implies a reduction in the ability of the 
cerebral arteries to buffer the pressure delivered to the brain through the carotid arteries. The 
Gosling Pulsatility Index (PI), will be calculated from the baseline cerebral blood flow velocity 
(obtained during the above-described protocol) as follows: PI = (MCAv(systolic) − 
MCAv(diastolic))/MFVMCA. 
o 
Total Cerebral Blood Flow (CBF) will be assessed using extracranial high-resolution duplex 
ultrasound to capture both diameter and time-averaged MFV of the bilateral internal carotid 
arteries (ICA) and vertebral (VA) arteries (i.e., the two primary arteries that supply the 
brain)11–13.  CBF will be calculated for each artery as follows: CBF = MFV x π(diameter/2)2 
and summed in order to estimate total cerebral blood flow12. 
o 
Neurovascular Coupling will be assessed by measuring the ΔMFVMCA  and ΔMFVPCA from 
baseline in response to the progressively difficult N-back mental task of executive function  
and a repetitive visual stimulus14–16.  MFVMCA and ΔMFVPCA will be collected using TCD 
ultrasonography as described above. The N-back Cognitive Test measures working memory 
and executive function and activates areas of the brain supplied by the MCA.  A computer 
program will display a series of numbers and the subject will be required to respond by 
clicking a button when the current number is identical to the same number N-trials previously.  
A control (0-back) level and two N-back levels will be performed. Numbers will be displayed 
with an inter-stimulus duration of one second with a 10-second pause between each level.  
Number sequence will vary between N-back conditions.  The number of correct responses 
will be recorded to control for performance on the cognitive task itself.  The repetitive visual 
stimulus activates the areas of the brain supplied by the PCA. A computer program will 
display a visual stimulus, as previously described. Briefly, the subject will be asked to focus 
their eyes on a screen displaying an alternating black and white checkerboard stimulus for 
varied amounts of time (~40s each stimulus). The subject will be required to open and close 
their eyes when prompted by the research team.  
o 
Post-testing blood sampling and urinalysis (visit 7 only). A urine sample and 4.0 
Tablespoons of blood will be collected to repeat baseline blood measures (except for APOE 
genotype and B vitamins, which only need to be performed once). 
VISITS 3 & 8: COGNITIVE FUNCTION (Virtual; 1.5 hour each) 
Subjects will be instructed to refrain from taking over the counter medications for 48 hours, vigorous 
aerobic exercise and alcohol for 24 hours before testing.  Subjects will be encouraged to eat a light meal 
or snack before coming to the lab. 
Cognitive function assessments can be performed in-person during visit 3 and visit 8, or alternatively can 
be completed virtually through REDCap with research staff. If participants choose to complete cognitive 
testing through virtual means, visit 3 and visit 8 will no longer be needed. 
Patient-Reported Outcomes (PROMIS) Measures (Visit 12). Subjects will answer a brief battery of self-
guided questionnaires (administered using an iPad, or online via REDCap) to determine their own 
perception of their health and well-being.  Outcome measures will include: fatigue, pain, physical function, 
sleep disturbance, anxiety, depression, alcohol use, and social abilities. 

 
9 
Memory function will be assessed by performance on the California Verbal Learning Test III (CVLT III) 
and the Wechsler Logical Memory and Visual Reproduction Tests.  Additional domains of cognitive 
function will be surveyed using the NIH Toolbox computerized tests to evaluate 1) attention, 2) episodic 
memory, 3) working memory, 4) language, 5) executive function, and 6) processing speed.  
• 
CVLT III - The subject will hear a list of 16 nouns in a fixed order over 5 learning trials. After each 
trial, the subject will be asked to recall as many words as they can in any order.  Following the 
learning trials, the subject must recall as many words on the list as they can immediately (short-delay) 
and following a 20-minute wait (delayed recall).  A second task involving recognition of target words 
from a list of 44-words read by the investigator is completed at the end of the test. This test can be 
performed in-person or virtually through REDCap and virtual screen sharing. 
• 
Wechsler Logical Memory Test (I and II). This test assesses logical memory function.  The subject 
will listen to the examiner read two stories and will be asked to repeat as many details of the stories 
as they can remember.  An immediate recall and delayed (20 minute) recall component will be used.  
Scores will be based on accuracy in recalling elements of the story. This test can be performed in-
person or virtually through REDCap and virtual screen sharing. 
VISITS 4 & 9: NEURONAL FUNCTION (CBBI; 2 hours each) 
Subjects will be instructed to refrain from taking over the counter medications for 48 hours, vigorous 
aerobic exercise and alcohol for 24 hours before testing.  Subjects will be encouraged to eat a light meal 
or snack before coming to the lab. 
Repeat MRI Screening Form. To confirm ability to safely participate in the MR scan. 
To gain initial insight into the possible central 
neural mechanisms mediating improvements in 
cognitive function with NR supplementation in 
older adults, we will use exploratory fMRI 
assessments of global and regional brain 
structure and task-induced neural activation 
patterns.  As there is no preliminary evidence 
suggesting a change in activation patterns 
following NR supplementation in older adults, all 
fMRI-based outcomes are considered 
exploratory in nature and are not included as a 
primary/secondary outcome.  
• 
The scanning portion of the study will take 
place at the UD Center for Biomedical Brain 
Imaging (CBBI). The MRI device for these scans is FDA approved for research with human subjects 
and has all the safety inherent in a clinical MRI scanner.  The radio frequency fields conform to 
guidelines determined by the FDA and the FDA has designated MRI scanners to be a non-significant 
risk device. MR techniques non-invasively produce images and measurements from tissues in the 
intact, living human.   
• 
Prior to going into the MRI scanner, the MRI technologist on duty will ask participants to remove all 
jewelry and metal objects from their pockets. Participants will be required to change into scrubs to 
prevent any possible risk from metallic objects or decorations in their clothing. 
• 
In an MRI scan the subject will lay down on a table and will be placed into a long donut-shaped 
magnet.  A specially designed coil will be placed around the head to provide better images (as is 
done with standard clinical examinations).  As the MRI scan is performed, the subject will hear loud 
rapping and knocking noises that are normal for a MRI scan. 
• 
The protocol will consist of an 8-min high-resolution structural scan to determine brain anatomy, a 6-
min scan of resting state activity to examine age-dependent functional brain connectivity, 
measurement of resting brain blood flow using arterial spin labeling (ASL) and a 10 minute cognitive 
Table 2 
Outcome type 
Task 
Assessment 
Structure 
-- 
Grey matter volume 
 
 
White matter volume 
 
 
White matter hyper-
intensities 
Resting state 
-- 
Functional brain 
connectivity 
Blood flow 
 
Arterial spin labeling 
Cognitive 
activation 
N-Back 
Executive function 
 
 
Working memory 

 
10 
task sensitive to working memory and executive function (N-back).  This test is sensitive to age-
related deficits in cognitive functions and to intervention. Subjects will follow instructions on a screen 
in front of them in the scanner and use a clicker to indicate their answer. Further, their vitals (heart 
rate and respiration rate) will be monitored via a respiration band that they will wear around their 
chest. 
• 
fMRI Data Acquisition and Analysis.  Images will be acquired on a research-dedicated whole-body 
3-Tesla Siemens Magnetom Prisma whole-body MRI scanner equipped with 64 channel head coil.  
Functional imaging will use T2*-weighted gradient-echo, echo-planar imaging (repetition time [TR] = 
1900 ms, echo time [TE] = 25 ms, flip angle = 69°, 39 slices parallel to the AC-PC line, thickness = 3 
mm, gap = 1 mm, 64 × 64 in-plane resolution, in-plane FOV = 22 cm).  High-resolution anatomical 
images, which take 6 min to obtain, will be acquired with a T1-weighted 3D magnetization prepared 
rapid gradient multi-echo sequence (MPRAGE; sagittal plane; TR = 2530 ms; TE = 1.64 ms, 3.5 ms, 
5.36 ms, 7.22 ms, 9.08 ms; GRAPPA parallel imaging factor 2; FOV = 256mm; flip angle = 7°; 192 
interleaved 1mm slices) covering the whole brain.  Note that through pilot development, our sequence 
may change slightly if a different combination of parameters is deemed more optimal.  Tools within 
the FSL framework will be used for data pre-processing and analysis, as well as tools within SPM, 
where appropriate (e.g., for resting state analyses).  At baseline and after treatment: regional grey 
matter normalized whole brain volume and white matter hyper-intensities will be assessed.  
Multivariate linear modeling of BOLD fMRI imaging data will be used to identify functional neural 
network expression during the resting state and working memory and executive function tasks.  
Whole brain analyses will be performed to assess connectivity and regions of interest specific to each 
cognitive task.  Relations between structures, resting state and functional neural network expression 
during each task will be assessed.  Associations among function, structure and behavioral 
performance will be determined using a network analysis. 
• 
Wechsler Visual Reproduction Test (I and II). This test assesses visuoconstructional and visual 
memory function.  The subject will be presented with a series of complex line drawing and will be 
asked first to copy the drawing onto a piece of paper, then re-draw the picture from memory following 
a 20-minute delay.  Drawings will be scored for accuracy and correct placement of picture elements. 
This test must be completed in-person, and will be administered during Neuronal Function visits #4 
and #9. 
• 
NIH Toolbox (This test must be completed in-person, and will be administered during Neuronal 
Function visits #4 and #9). 
o 
Attention. Attention will be measured by the NIH Toolbox Inhibitory Control and Attention Test. 
The Flanker task measures both a participant’s attention and inhibitory control. The test requires 
the participant to focus on a given stimulus while inhibiting attention to stimuli (fish for ages 3-7 or 
arrows for ages 8-85) flanking it. Sometimes the middle stimulus is pointing in the same direction 
as the “flankers” (congruent) and sometimes in the opposite direction (incongruent). Scoring is 
based on a combination of accuracy and reaction time. 
o 
Episodic Memory. Episodic Memory refers to cognitive processes involved in the acquisition, 
storage and retrieval of new information and will be measured with the NIH Toolbox Picture 
Sequence Memory Test. The Picture Sequence Memory Test is a measure developed for the 
assessment of episodic memory. It involves recalling increasingly lengthy series of illustrated 
objects and activities that are presented in a particular order on the computer screen. The 
participants are asked to recall the sequence of pictures that is demonstrated over two learning 
trials; sequence length varies from 6-18 pictures, depending on age. Participants are given credit 
for each adjacent pair of pictures (i.e., if pictures in locations 7 and 8 and placed in that order and 
adjacent to each other anywhere – such as slots 1 and 2 – one point is awarded) they correctly 
place, up to the maximum value for the sequence, which is one less than the sequence length (if 
there are 18 pictures in the sequence, the maximum score is 17, because that is the number of 
adjacent pairs of pictures that exist). 
o 
Working Memory. Working Memory refers to a limited-capacity storage buffer that becomes 

 
11 
overloaded when the amount of information exceeds capacity and is measured by the NIH 
Toolbox List Sorting Working Memory Test. This test requires immediate recall and sequencing of 
different visually and orally presented stimuli. Pictures of different foods and animals are 
displayed with accompanying audio recording and written text (e.g., “elephant”), and the 
participant is asked to say the items back in size order from smallest to largest, first within a 
single dimension (either animals or foods, called 1-List) and then on 2 dimensions (foods, then 
animals, called 2-List). The score is equal to the number of items recalled and sequenced 
correctly. 
o 
Processing Speed. Processing Speed is either the amount of time it takes to process a set 
amount of information, or, the amount of information that can be processed within a certain unit of 
time. It is a measure that reflects mental efficiency, and will be measured with the NIH Toolbox 
Pattern Comparison Processing Speed Test. This test measures speed of processing by asking 
participants to discern whether two side-by-side pictures are the same or not. Participants’ raw 
score is the number of items correct in a 90-second period. The items are designed to be simple 
to most purely measure processing speed.  
o 
Executive Function. Executive Function is the capacity to plan, organize, and monitor the 
execution of behaviors that are strategically directed in a goal-oriented manner and is measured 
by the NIH Toolbox Dimensional Change Card Sort Test (DCCS). DCCS is a measure of 
cognitive flexibility. Two target pictures are presented that vary along two dimensions (e.g., shape 
and color). Participants are asked to match a series of bivalent test pictures (e.g., yellow balls and 
blue trucks) to the target pictures, first according to one dimension (e.g., color) and then, after a 
number of trials, according to the other dimension (e.g., shape). “Switch” trials are also employed, 
in which the participant must change the dimension being matched. For example, after 4 straight 
trials matching on shape, the participant may be asked to match on color on the next trial and 
then go back to shape, thus requiring the cognitive flexibility to quickly choose the correct 
stimulus. Scoring is based on a combination of accuracy and reaction time. 
o 
Language. NIH Toolbox focuses on two aspects of language: vocabulary knowledge, which is 
fundamental to the growth of knowledge and which also has a very high association with overall 
intelligence, or what has been called the "g factor”, and oral reading skill, which reflects level and 
quality of prior educational experiences, and provides a fairly robust indication of verbal 
intelligence that is relatively undisturbed by many medical conditions that affect the brain. 
Vocabulary language will be measured by the NIH Toolbox Picture Vocabulary Test while oral 
reading will be measured by the NIH Toolbox Oral Reading Recognition Test.  
o 
The NIH Toolbox Picture Vocabulary Test measures receptive vocabulary and is 
administered in a computerized adaptive format. The respondent is presented with an audio 
recording of a word and four photographic images on the computer screen and is asked to 
select the picture that most closely matches the meaning of the word.   
o 
During NIH Toolbox Oral Reading Recognition Test the participant is asked to read and 
pronounce letters and words as accurately as possible. The test administrator scores them as 
right or wrong. For the youngest children, the initial items require them to identify letters (as 
opposed to symbols) and to identify a specific letter in an array of 4 symbols. The test is 
given in a computerized adaptive format. 
 
Visit 4: START Intervention (30 min; NOVA Lab) 
o 
Receive 12-week supply of study pills (intervention instructions provided by member of 
research team) 
VISITS 5 & 6: Bi-Weekly CHECK-IN Visits (Virtual or NOVA Lab*; 30 minutes) 
o 
Consult (bi-weekly). Brief check-in/consult with study coordinator (physical symptom 
survey);  

 
12 
o 
Patient-Reported Outcomes (PROMIS) Measures (monthly). Subjects will answer a brief 
battery of self-guided questionnaires (administered using an iPad, or online via REDCap) to 
determine their own perception of their health and well-being.  Outcome measures will 
include: fatigue, pain, physical function, sleep disturbance, anxiety, depression, alcohol use, 
and social abilities. Subjects who cannot complete PROMIS measures online will report to 
the lab on a monthly basis to complete this measure. 
OVERVIEW OF INTERVENTION (see attached Investigator’s Brochure and Appendix for additional 
data) 
Nicotinamide riboside (NR) is a safe, naturally occurring vitamin B3 derivative found in yeast, bacteria, and 
mammalian tissues.  Additionally, NR has been detected in cows’ milk17.  Each NR capsules contain 250 
mg of nicotinamide riboside chloride mixed with microcrystalline cellulose.  The appearance is a blue 
powder within a blue vegetarian capsule. NR has been generally recognized as safe by the FDA (GRAS 
No. 635) and has been developed as a commercially available dietary ingredient for human 
consumption under the trade name NIAGEN® (ChromaDex, Inc. Irvine, CA).  No serious adverse events 
have been reported in humans taking NR.  A summary of the currently available safety and toxicity data 
are presented below. 
Summary of NR safety & toxicity in preclinical models and clinical trials to date:  
• 
NR is non-mutagenic in bacteria at doses of 50-5000μg in a reverse mutagenicity (Ames) assay, and 
non-cytotoxic in chromosomal aberration studies in human peripheral blood lymphocytes treated with 
1.25 – 5 mg/ml NR.  Results of an in vivo micronucleus assay revealed no cytotoxicity or 
chromosomal damage in bone marrow-derived erythrocytes obtained from Sprague-Dawley rats at 
24-48 hours post ingestion of up to 2,000 mg/kg NR. Using the FDA recommended surface area 
conversion factor, this is equivalent to a dose of ~19,200 mg/day for an average 60kg human and is 
~20-fold higher than the dose for the current study (500 mg, 2x/day)18. 
• 
No acute toxicity, abnormal pathology, or mortality was observed over 2-weeks following a single 
dose of 5,000 mg/kg NR in male and female rats.  Likewise, no treatment-related mortality was 
observed during a 90-day oral toxicity study in rats treated with 300, 1000 or 3000 mg/kg/day NR19.  
The lowest observed adverse effect level (LOAEL) reported was 1,000 mg/kg/day19, which is 
equivalent to a dose of ~9,600 mg/day for an average 60kg human or ~10-fold higher than the daily 
dose for this study18.  Further, a recent study in mice treated with 400mg/kg/day NR for 16 weeks 
(i.e., ~15% of a mouse’s lifespan at a human equivalent dose of ~ 2,000mg/day) reported no adverse 
increase in mortality rate, end organ damage, or tumor formation20. 
• 
There is limited evidence in animal models of cancer suggesting treatment with NAD+ boosting 
compounds could increase cancer cell proliferation and exacerbate cancer progression and 
metastasis; however, in other studies, NAD+ precursors have been shown to have favorable effects 
on metabolism that prevent or limit cancer growth21.  
• 
A recently conducted Phase-1 clinical trial in humans (Trammel et al., Nat Commun. 2016) found that 
NR was safe for human consumption and reported no serious adverse effects at doses ranging from 
100 – 1,000mg22. 
• 
Data from our own recently published 
randomized, placebo-controlled crossover 
pilot study of long-term dosing in 24 healthy 
older adults23. indicate no serious adverse 
events (Table 3) associated with the 
proposed dose (500 mg, 2x/day), and no 
change in markers of liver or renal function23.  
Rationale for Proposed Treatment Dose, 
Duration and Frequency 
• 
Bioavailability. Because NR is directly 
taken up by cells and metabolized into 
NAD+ and related metabolites, NAD+ has 
proven to be undetectable in the plasma. 
Table 3. Treatment emergent adverse events from 
pilot study. Based on N=30 randomized subjects 
Adverse Event 
Placebo 
NR 
Headache 
4 
0 
Nausea 
0 
1 
Skin Rash 
1 
1 
Flushing/Hot flashes 
2 
1 
Fainting 
1 
0 
Drowsiness 
1 
0 
Leg cramps 
0 
1 
Increased Bruising 
0 
1 
Data represent number (n) of times AE was 
reported.  Number of subjects reporting AEs (n=7); 
Number of subjects reporting ≥ 2 AE (n=5). 
 

 
13 
As such, assessment of the NAD+ metabolome in peripheral blood mononuclear cells (PBMCs) 
has emerged as the gold standard method of evaluating NAD+ bioavailability in response to 
supplementation with NAD+ boosting compounds22,23. During a recently published Phase I clinical 
trial with NR in 12 healthy adults (Trammel et al., Nat. Comm. 2016), the concentration of NAD+ 
and related metabolites were dose-dependently elevated in PBMCs compared with baseline 
following a single ingestion of 100, 300, and 1000 mg NR22.  
• 
Rationale for Dose and Duration. For the present study, we have chosen to study a dose of 
500mg, 2x/day (i.e., 1,000 mg/day) for 12 weeks.  We have chosen to standardize the dose 
among subjects, rather than administer NR in relation to body mass in order to increase the 
translational potential of the proposed work, as formulation of a treatment based on body mass is 
impractical in a clinical setting. The rationale for this dose and treatment duration is based on: 
o 
Preclinical studies using NR in mice demonstrating efficacy for improving physiological 
function (e.g., insulin sensitivity, mitochondrial biogenesis, fatty acid oxidation) with doses 
ranging from 250-400 mg/kg/day, which translate to an equivalent dose in humans of 
between 1,200 – 2,000 mg/day for an average 60kg adult; 
o 
Results of a phase I clinical trial demonstrating an increase in NAD+ and related 
metabolites at this dose in healthy humans (Appendix, Figure 1); 
o 
The PI’s own pilot study (clinicaltrials.gov registry: NCT2921659) demonstrating efficacy 
of this dose for improving measures of arterial stiffness and blood pressure in healthy 
(cognitively normal) middle-aged and older adults with a shorter duration than the 
proposed study; 
o 
At least 2 other clinical trials in healthy or obese individuals using a similar dose 
(NCT02300740, NCT02303483). 
• 
Rationale for Frequency of Doses.  Subjects will be advised to consume NR or placebo pills 
twice a day (one dose in the morning and one in the evening) in order to maintain elevated 
circulating NAD+ levels and to lower the risk of potential side effects caused by a larger single 
dose. The exception to this will be in the morning of testing, in which subjects will not take their 
morning dose until completion of the testing session in order to avoid any acute effects of the 
compound on the proposed outcomes.  Subjects will be advised to take pills with food in order to 
a) maximize absorption; b) increase subject adherence by timing pill intake with meals; and c) 
decrease risk of nausea or GI discomfort. 
Description of Placebo Capsules. The placebo capsules contain microcrystalline cellulose within 
vegetarian capsules.  The appearance is a blue powder within a blue capsule. 
 
Investigational New Drug Application. In addition to the details above related to the safety of NR 
supplementation in humans, we have also received Investigational New Drug (IND) status from the Food 
and Drug Administration (CDER Division of Neurological Products) for the use of NR in patients with MCI 
(IND#:135449).   
 
ADMINISTRATION, ADHERENCE AND SUBJECT MONITORING 
Intervention Administration. Placebo or NR capsules will be packaged and distributed by ChromaDex 
Inc. (under trade name, NIAGEN®) in individual containers.  12 weeks’ worth of capsules will be 
administered to subjects by the research team at the beginning of the trial.  Subjects will be provided with 
explicit instructions for dosing and frequency including instructions for missed doses.   
Monitoring Adherence (pill count). Subjects will be instructed to bring their used and unused pill 
containers to the last post visit and, at which time a member of the research team will count the number 
of pills remaining in the container to assess adherence to the intervention. 
Plan for Monitoring Adverse Events (AE’s) and Serious Adverse Events (SAE’s) 
Adverse Event (AE): any untoward or unfavorable medical occurrence in a human study participant, 
including any abnormal sign (e.g. abnormal physical exam or laboratory finding), symptom, or disease, 

 
14 
temporally associated with the participants’ involvement in the research, whether or not considered related 
to participation in the research.  
Adverse Event Recording 
The period for recording AE’s will begin at the time of informed consent and will end at the time that the 
participant completes all testing, or is withdrawn from the trial.  At each in-person or phone check-in, a 
blinded member of the study team will seek information from the participant on adverse events by specific 
questioning using a standardized physical symptom survey.  Information on all AE’s reported during the 
study period will be recorded immediately in the case report form (CRF).  Adverse events will be 
described by duration (start and stop dates and times), severity, outcome, treatment and relation to study 
drug, or if unrelated, the cause, as described in the Data and Safety Monitoring Plan (DSMP).   
Serious Adverse Event (SAE): any adverse event that: 
• 
Results in death; 
• 
Is life threatening, or places the participant at immediate risk of death from the event as it occurred; 
• 
Requires or prolongs hospitalization; 
• 
Causes persistent or significant disability or incapacity; 
• 
Results in congenital abnormalities or birth defects; 
• 
Is another condition which investigators judge to represent significant hazards. 
If a SAE occurs while the participant is on campus for a scheduled visit, the participant will be sent to the 
Christiana Care Medical Aid Unit (“Urgent Care”) on the STAR Campus.  If a participant contacts the 
laboratory or PI prior to seeking treatment for an ongoing AE or SAE, the participant will be directed to 
seek immediate medical treatment (e.g., visit their primary healthcare provider or, if requiring immediate 
attention, the nearest Urgent Care facility or Emergency Department).  Any participant who is 
experiencing a life-threatening medical emergency will be instructed to call 911. 
  
Reporting of SAE’s 
All participants experiencing a SAE will be instructed to notify the principal investigator after seeking 
immediate medical attention.  As detailed in the Data and Safety Monitoring Plan (DSMP), all SAE’s will 
be reported to the IRB, DSMB and other regulatory bodies (e.g., FDA, NIH) within 24 hours of the event 
being reported to the investigator.  An expedited report of the SAE can be submitted by telephone, fax, or 
email and will be followed by a detailed, written SAE report as soon as possible.  In the event that a 
participant calls the PI or another member of the study team prior to receiving treatment for an ongoing 
SAE, that participant will be instructed to seek immediate medical attention (e.g., visit urgent care).  
 
Unblinding in Response to a SAE 
All participants will be given a “Clinical Trial Participant Card” at the time of informed consent, which will 
provide the dates of their anticipated involvement in the study and important details regarding the active 
compound under investigation.  The card will also provide a QR code to access the clinicaltrials.gov 
registry for this trial.  Participants will be instructed to keep this card with them at all times (e.g., in their 
wallet) and to provide it to emergency personnel or other healthcare professionals if seeking treatment for 
an AE or SAE.  In the event that emergency personnel or other healthcare professionals responding to a 
SAE determine that it is medically necessary to know the treatment to which a participant is 
randomized, the card will provide the contact information for the PI’s office.  PI will program their office 
line to forward all calls to their personal phone outside of normal business hours.  In case of an 
emergency, the PI will be capable of breaking the blind for that participant. 
 
STUDY TIMELINE 
Experimental sessions (baseline & follow-up) will be conducted over a 7 day period.  The order of these 
visits may be switched as needed in order to facilitate scheduling.  Subjects will continue their treatment 
(NR or placebo pills) until experimental sessions for each condition are completed; however, subjects will 

 
15 
be instructed to refrain from taking study pills within 24 hours of an experimental session, to avoid any 
confounding effects of acute NR supplementation.  In the event of a conflict (e.g., due to scheduling or 
illness), experimental sessions may be scheduled ± 7 days from the ideal testing window.  We anticipate 
that the typical time lapse between completion of screening measures and the beginning of the 
intervention will be no more than 1 week and that the study will take approximately 15 weeks to complete.  
The study will require 16 hours of the subject’s time in the clinical trial. 
 
7.  STUDY POPULATION AND RECRUITMENT 
 
Study Population 
 
58 older adult men and women of all races and ethnic backgrounds between the ages of 60-90 years with 
cognitive scores indicative of mild cognitive impairment that includes impaired memory function (i.e., 
“amnestic MCI or “aMCI”) will serve as subjects for this study.  To account for a 25% subject exclusion 
rate due to dropout/experimental failure, failed screening or conversion to dementia (15 subjects), a total 
of 73 patients with aMCI (~20 subjects/year over 4 years) will be recruited for this study in order to 
meet our enrollment goal.  
 
Recruitment and Screening 
Participants for this study will be recruited through the “Screening eligibility of older adults to participate in 
clinical trials related to memory” study (UD IRB #1318668), which is being conducted by Dr. Christopher 
Martens and Dr. Curtis Johnson.  Participants will be primarily recruited through posted flyers and direct 
mailings targeted towards older adults with a self-report of memory complaints.  Additional subjects will be 
recruited through the Swank Memory Center for Memory Care and Geriatric Consultation (“Swank 
Memory Center”) in Wilmington, DE in collaboration with co-investigator, James Ellison, M.D.  Specific 
details regarding subject recruitment are described in the screening protocol.  Briefly, subjects will 
undergo a brief modified telephone pre-screening for cognitive status (TICS-m) and those qualified will 
undergo a more comprehensive in person cognitive evaluation with a research nurse.  Individuals with 
memory scores indicative of amnestic MCI that express interest in participating in this study will be 
recruited for enrollment into this clinical trial by the study coordinator.  Additionally, this study will be listed 
on the Alzheimer’s Prevention Registry. 
 
 
 
 
 
Final eligibility will be determined by the PI based on the inclusion/exclusion criteria stated below: 
 
Inclusion Criteria 
• 
Cognitive function scores consistent with amnestic mild cognitive impairment based on pre-
screening evaluation; 
• 
age 60-90 years; 
• 
MMSE score >21 at time of initial consent; 
 
Exclusion Criteria 
• 
blood chemistries indicative of abnormal renal, liver, thyroid and adrenal function; estimated 
glomerular filtration rate using the MDRD prediction equation must be ≥30 ml/min/1.73 m2; 
• 
any clinically significant abnormal blood chemistry values as determined by the NMPCC nurse 
practitioner; 
• 
major psychiatric disorder (e.g. schizophrenia, bipolar disorder, major depression within past two 
years);  

 
16 
• 
neurological or autoimmune conditions affecting cognition (e.g. Parkinson’s disease, epilepsy, 
multiple sclerosis, mild or severe traumatic brain injury, large vessel infarct);  
• 
concussion within last 2 years and ≥ 3 lifetime concussions; 
• 
current systemic medical illnesses, not including diabetes (e.g. cardiovascular disease, cancer, 
renal failure);  
• 
prior history of any type of cancer other than basal cell carcinoma; 
• 
substance abuse or dependence (DSM-V criteria); 
• 
current use of medications used to treat dementia (e.g., anticholinesterase drugs) or other drugs 
likely to affect cognition (e.g., anticholinergic drugs, long-acting benzodiazepines);  
• 
claustrophobia, metal implants, pacemaker or other factors affecting feasibility and/or safety of 
MRI scanning*; 
• 
current smoking (including marijuana) within the past 3 months; 
• 
hospitalization as a result of COVID-19. 
• 
History of heart palpitations or arrhythmias   
 
* In order to protect the health and safety of the participants, exclusion criteria for this study will include 
any contraindication to magnetic resonance scanning (e.g., metal in body, claustrophobia, pregnant). 
These exclusions are specific to MRI and are consistent with most studies involving MRI. Potential 
participants will be screened for the presence of any of these exclusion criteria prior to participating in this 
MRI study and before each MRI visit by having subjects complete an MRI screening form. 
Describe what (if any) conditions will result in PI termination of subject participation. 
 
The primary exit criteria will include: 
• 
completion of the study; 
• 
failure to comply with the requirements of the study; 
• 
lack of ability to continue to provide consent during the study; 
• 
development of dementia during the study; 
• 
treatment for impaired cognitive function by PCP; 
• 
change in medication status that my affect primary outcomes (as determined by the PI); 
• 
any serious adverse event that results in unblinding, prolonged disruption of the intervention or is 
deemed unsafe for the participant to continue in the trial. 
Other exit criteria will include cardiovascular or metabolic disease-related events (e.g., myocardial 
ischemia/angina, myocardial infarction, stroke, congestive heart failure, hyperglycemia, etc.), major 
surgery and other serious changes in health status. Subjects will also have the option of withdrawing from 
the study at any time for any reason. The number of subjects exiting the study and the reasons for exit 
will be carefully documented.  Subjects who withdraw from the study will be replaced in order to achieve 
the sample size required for appropriate statistical power. 
8.  RISKS AND BENEFITS 
 
List all potential physical, psychological, social, financial or legal risks to subjects (risks listed 
here should be included on the consent form). 
 
• 
Nicotinamide Riboside (NR) and Placebo Capsules - Subjects will either be given nicotinamide 
riboside (NR) capsules (Niagen®; 500 mg 2x/day) to raise blood levels of NAD+, or placebo 
capsules that contain inactive ingredients (microcrystalline cellulose within vegetarian capsule).  
Potential side effects associated with NR may include mild-to-moderate cases of headache, 
feelings of warmth, hot flushing sensations, gastrointestinal discomfort, and fatigue.  There are 
currently no reports of serious adverse side-effects to NR supplementation; however, all adverse 
events will be closely monitored.  To lessen the risk of side effects, subjects will take capsules 
twice a day instead of all at once.  If they miss a dose, subjects will be instructed not to double 
the number of capsules that they take and to just take the next dose at the regularly scheduled 
time. If subjects are allergic to or have had an adverse event after taking one of the above-
mentioned drugs or supplements, they will be asked to notify the investigator before participating. 

 
17 
Per Niacin’s FDA label, cardiac arrhythmias and palpitations have been reported during Niacin 
use. Niacin is a closely related compound to nicotinamide riboside. There are ongoing clinical 
trials using the current compound, nicotinamide riboside, as an intervention for preventing atrial 
fibrillation in people with heart failure; thus, the actual risks of cardiac arrhythmias with NR are 
unknown. 
• 
Blood Draw - When the needle goes into a vein, it hurts for a short time and there may be 
redness or swelling around where the needle goes into the skin.  There is a small chance you 
may feel lightheaded or faint.  In about 1 in 10 cases, a small amount of bleeding under the skin 
will cause a bruise.  A risk of a blood clot forming in the vein is about 1 in 100.  The risk of 
infection or significant blood loss is less than 1 in 1,000.  The total amount of blood being drawn 
over the entire study is approximately 9.0 tablespoons (less than 1/3 pint). Subjects should not 
donate blood 8 weeks before or after taking part in this study. 
• 
Genetic Risk for AD – One of the blood tests will determine whether or not the subject carries a 
gene that has been associated with risk for Alzheimer’s disease (AD).  People with this gene 
have a higher chance of developing AD compared with people who do not carry the gene.  Some 
people who carry the gene may never develop AD.  Others may develop AD even though they do 
not carry the gene.  Subjects will be provided with the results of this test upon request only.  
• 
Cerebrovascular Function - There are no risks associated with breathing slightly higher or lower 
amounts of carbon dioxide. The use of CO2 to manipulate brain blood flow in humans has been 
applied clinically and in the research setting for decades without any adverse events.  Subjects 
may feel an increase in heart rate, flushed skin, and minor disorientation or slight metallic taste 
while breathing the carbon dioxide mixture. A mild headache is also possible.  Subjects may 
experience a dry mouth due to the use of the facemask during the test. 
• 
MRI Scan - MRI is an imaging technique that uses radio waves and magnetic fields to produce 
images of internal structures in your body. Unlike X-rays, the MRI does not use any ionizing 
radiation, and it does not use radioactivity, so there is no radiation related risks from having an 
MRI scan done on you. Below there is a description of MRI related risks and what is being done 
to reduce any possible risks associated with them:  
o 
Metal: The MRI scanner produces a constant strong magnetic field, which may cause 
any metal implants, clips, or implanted medical devices within your body to shift position 
or malfunction. You will not be allowed to participate in this study if you have any 
implanted metal, clips or devices. You will be screened to make sure that it is safe for you 
to enter a strong magnetic field. Please provide us with as much information as you can, 
for example if you had surgery in the past, so that we may decide whether it is safe for 
you to be a participant. Metallic objects brought into the MRI environment can become 
hazardous projectiles and can also interfere with the data quality. To minimize this risk, 
metal earrings, other piercings, necklaces and any other metal in contact with your body 
must be removed prior to the study. You must also remove all items from your pockets, 
including coins, electronics (including cell phones and hearing aids) and wallets. You 
must remove belts with metal buckles, and you may be asked to change into a gown that 
we will provide if your clothing contains significant metal, including metal underwire bras. 
o 
Inner ear damage: MRI scanning produces loud noises that can cause damage to the 
inner ear if appropriate hearing protection is not used. Earplugs and/or headphones will 
be provided to protect your ears.  
o 
Claustrophobia: When inside the MRI scanner, the “bore” of the scanner will surround 
the part of the body that is being scanned.  In the case of fMRI, we are interested in brain 
activity, and the head will be centered inside a close-fitting scanning coil positioned in the 
bore of the scanner. If the subject feels anxious in confined, spaces they may not want to 
participate. If they are unsure, they can try the “mock” scanner at the MRI facility to 
evaluate their comfort level with the enclosed space of the magnet bore. If they decide to 
participate and begin to feel claustrophobic, they will be able to communicate with the 
research team via the intercom or the squeeze ball and the test will be discontinued.  

 
18 
Subjects who do not complete MRI testing will still be allowed to continue with the trial.  
o 
Burns: In rare cases, contact with the MRI transmitting and receiving coil, conductive 
materials such as wires or other metallic objects, or skin-to-skin contact that forms 
conductive loops may result in excessive heating and burns during the experiment. The 
operators of the MRI scanner will take steps, such as using foam pads when necessary, 
to minimize this risk. Tattoos with metallic inks can also potentially cause burns. In 
addition, please let the MRI operator know immediately if you experience any heating or 
burning sensations during a scan. The scanning session will be stopped as soon as you 
tell the operator.  
o 
Nerve or muscle stimulation. While the scanner is operating, there is a small chance 
that the rapidly changing magnetic fields could cause a slight tingling sensation or a 
muscle twitch, usually felt in the upper arms or torso. While these sensations may be 
startling, they are not dangerous or a health risk, and they have no lasting consequences. 
The sensations should stop when the scan ends. Because these sensations may 
nevertheless be distracting or even possibly uncomfortable, please squeeze the signal 
bulb to alert the scanner operator if you feel tingling or muscle twitching, and we will 
immediately stop the scan. You will then have the opportunity to choose to withdraw from 
the study or to continue.  
o 
Other Risks. Besides the risks listed above, there are no other known risks from the 
magnetic field or radio waves at this time. Although functional MRI scanning has been 
used for more than 20 years, long-term effects are unknown.  
There are no alternative methods that would provide the same type and accuracy of information 
as the state-of-the-art procedures proposed in this application. 
In your opinion, are risks listed above minimal* or more than minimal? If more than minimal, 
please justify why risks are reasonable in relation to anticipated direct or future benefits. 
(*Minimal risk means the probability and magnitude of harm or discomfort anticipated in the research are 
not greater than those ordinarily encountered in daily life or during the performance of routine physical or 
psychological examinations or tests) 
 
The risks associated with this research are minimal and not greater than those encountered during the 
performance of routine physical or psychological examinations. 
 
What steps will be taken to minimize risks? 
 
Management of general risks of the proposed study: 
• 
Having only qualified and experienced personnel perform the procedures; 
• 
Using only safe, well-established procedures; 
• 
Constant monitoring of the subjects by the members of the investigative team; 
• 
Instating appropriate clinical supervision, availability of emergency equipment and medications 
(with well-planned emergency procedures), and the overall safety procedures in place within the 
STAR Health Sciences Complex; 
• 
Establishing a Data and Safety Monitoring Committee to periodically review and evaluate adverse 
events related to study procedures and/or treatments. 
Management of specific risks related to drugs/supplements: 
• 
screening for adverse events and allergies to drugs; 
• 
obtaining Investigational New Drug (IND) approval from the FDA; 
• 
working collaboratively with ChromaDex, Inc. and the FDA to ensure that the NR and placebo 
pills meet all regulatory and safety guidelines, and that there is continuing effective information 
sharing; 

 
19 
• 
using a dose of NR therapy that is based on my pilot study, has been shown to have efficacy, but 
does not result in adverse side effects in human subjects. 
Management of specific risks related to the collection of MRI data: 
• 
This protocol will be performed using an MR scanner employing pulse sequences and hardware 
that have been approved by the FDA for human clinical use. The field strength is 3 Tesla and all 
relevant operating characteristics (RF power deposition, rate of change of the field gradients, coil 
design) fall within the limits of FDA guidelines for NMR exposure. Participants will be carefully 
screened to exclude those who may have metal in or on their bodies that cannot be removed (e 
g., bullets, metal filings, body piercings, etc.). MR Facility rules strictly forbid staff from entering 
the magnet room carrying metal objects. The risk of claustrophobia is minimized by screening 
subjects for self-reported claustrophobia and making sure the subject is lying comfortably with 
head and neck supported and providing ear protection with headphones, a mirror to see out, a 
button to signal distress, and an intercom.  Scan time will be kept to a minimum.  If they are 
unsure about whether or not they may be pregnant, female participants will be given the 
opportunity to complete a urine pregnancy test immediately before the scanning period, and 
those with a positive result will not be scanned. With regard to PNS, participants are given a 
squeeze ball to use in case of an emergency. They are informed that if they experience PNS 
related sensations or are otherwise uncomfortable, they can alert the MRI technologist via the 
squeeze ball and the technologist will stop the scan immediately.  
• 
All information obtained during the study will be held in strict confidence to the fullest extent 
possible by law. In no case will a participant’s personal identifiable information be shared with any 
other individuals or groups without their expressed written consent. MR Images will be stored on 
secured computer servers and will be archived indefinitely. Non-identifiable images of MR scans 
may be used for teaching purposes, be presented at meetings, published, and also shared in 
databases accessible to other researchers for further research and educational purposes. The 
name or other identifying information associated with the participant will not be used in any 
publication or teaching materials without their specific permission. 
Describe any potential direct benefits to participants. 
There may be no direct benefit to subjects participating in this research study; however, subjects will 
receive the results of their screening assessments (i.e., blood glucose status, plasma lipids and 
lipoprotein profile, blood pressure, blood chemistries).  These results will not be interpreted but are 
provided for information. Subjects will be encouraged to discuss their results with their PCP. 
Describe any potential future benefits to this class of participants, others, or society. 
The findings from the proposed research should provide important new information regarding the 
influence of NR supplementation upon multiple domains of physiological function including vascular, 
cognitive and neuronal function in older adults with aMCI.  In addition, the proposed research should 
provide important insight into a potential mechanism involved in the modulation of cerebrovascular 
function with NR (i.e. oxidative stress).  Together, this information will contribute to the knowledge of how 
to prevent and treat cerebrovascular and cognitive dysfunction in older adults with aMCI and possibly 
lead to future insight into reducing Alzheimer’s disease risk. 
 
If there is a Data Monitoring Committee (DMC) in place for this project, please describe when and 
how often it meets. 
 
This protocol has been reviewed and approved by a Data and Safety Monitoring Board (DSMB) which will 
convene every 6 months to monitor patient safety, data quality and evaluate study progress.  A copy of 
the DSMB charter as approved by the DSMB is attached with this protocol. 
 
9.  COMPENSATION 
 
Will participants be compensated for participation? Yes 

 
20 
 
Subjects will receive monetary reimbursements for completion of the main experimental sessions.  
Subjects will be compensated per visit for their time in the form of a single check that will be mailed upon 
completion or withdrawal from the study. There is no compensation for the screening session (Visit 1) 
because subjects will be receiving medical information from all of the screening tests free of charge. This 
information will be provided upon completion of the study.   Subjects will be compensated for any visit that 
they attempt to complete; however, they will not be compensated if they skip a visit altogether.  For 
example, if they attempt to complete the baseline MRI (Visit 4) but ultimately cannot go through with the 
procedures (e.g., due to claustrophobia), they will still be compensated for Visit 4; however, since they will 
not have completed a baseline visit, they will not be scheduled for the follow-up MRI (Visit 9) and will 
receive no compensation for that visit. 
 
Compensation does not include travel time (we will compensate subjects for their travel if they wish at the 
current IRS approved mileage rate). If a subject withdraws or is withdrawn from the study, they will 
receive any health information collected and will be compensated for the study visits that they have 
already completed up to the time of withdrawal.  Compensation is based on completion of study visits, not 
individual procedures.  Subjects will be compensated for completing the majority of procedures in a visit.  
If a subject does not complete a visit at baseline, that visit will not be scheduled for follow-up and no 
compensation will be given for the follow-up visit.  A table outlining the total compensation for each visit is 
presented below. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
10.  DATA 
 
Will subjects be anonymous to the researcher? No. 
 
If subjects are identifiable, will their identities be kept confidential? (If yes, please specify how) 
All subject identities and records will remain strictly confidential. Individual subject data will be coded and 
will not be associated with subject name.  Documents that contain subject identifies (e.g., signed informed 
consent) will be kept in a separate locked filing cabinet.  A list of names and participant numbers will be 
encrypted and stored on a password protected computer.  This list will be kept for 5 years after study 
completion, after which it will be permanately deleted.  All information obtained by the NMPCC, including 
electronic medical records, will be stored on a HIPAA compliant database.   
Compensation Schedule 
 
Visit # 
Purpose 
Duration  
Total 
Screening 
Visit 1 
Informed Consent & 
Screening Measures 
2 hr 
No compensation 
 
Subjects receive 
free health 
information 
Baseline 
Testing 
Visit 2 
Vascular Function 
3 hr 
$30 
Visit 3 
Cognitive Function 
1.5 hr 
$22.50 
Visit 4 
Neuronal Function/ 
Start Intervention 
2 hr 
$30 
Intervention 
Period 
No Visit 
Check-In 
10 min 
$9.00 
Visit 5 
Check-In 
0.5 hr 
$9.00 
No Visit 
Check-In 
10 min 
$9.00 
Visit 6 
Check-In 
0.5 hr 
$9.00 
No Visit 
Check-In 
10 min 
$9.00 
Follow-
Up 
Testing
Visit 7 
Vascular Function 
3 hr 
$30 
Visit 8 
Cognitive Function 
1.5 hr 
$22.50 
Visits 9 
Neuronal Function  
2 hr 
$30 
 
Total Compensation 
$210 

 
21 
 
How will data be stored and kept secure (specify data storage plans for both paper and electronic 
files. For guidance see http://www.udel.edu/research/preparing/datastorage.html )    
 
Physical data will be stored in a locked file cabinet in the PI’s lab space and will only be accessible by 
members of the research team.  Physical data that are transcribed into an electronic database, and 
electronically captured data will be kept on a password protected laboratory server that is maintained by 
the University of Delaware.  Electronic data will be periodically backed-up onto an external hard drive that 
will be kept in a locked office space.  All of the ultrasound images and files generated by the SphygmoCor 
and RespirAct devices will be coded with an identification number and will not contain the name of the 
subject.  The names of subjects will not be identified in any publication arising from these studies.  Only 
the PI and research staff will have access to data from this study.  With subject consent, biological 
samples (plasma/serum, peripheral blood mononuclear cells) will be kept for retrospective analyses 
related to aMCI and physiological function (this will not be conducted without IRB approval). 
 
How long will data be stored? All data will be stored in a locked cabinet or a password protected 
computer indefinitely. 
 
Will data be destroyed?  □ YES   X NO (if yes, please specify how the data will be destroyed)  
 
Will the data be shared with anyone outside of the research team?  □ YES   XNO (if yes, please list 
the person(s), organization(s) and/or institution(s) and specify plans for secure data transfer) 
 
How will data be analyzed and reported?  
 
To determine if pre-intervention differences exist between groups, subject characteristics (e.g. total body 
fat, fasting blood glucose, etc.) will be compared between the two groups using unpaired t-tests. If 
assumptions of normality are met, separate linear regression models will be fit to compare NR vs. placebo 
(independent variable) with respect to change (baseline vs. week 12) for each of the outcome variables. 
Linear regression methods will be used to determine the association between/among changes in the 
primary or secondary outcomes in response to NR supplementation (e.g., to examine the association 
between changes in cognitive function and changes in arterial stiffness or cerebrovascular function). If 
assumptions of normality are not met, alternative strategies will be used, including transformation of 
variables, generalized linear mixed models, and non-parametric regression. To account for the blocked 
randomization scheme, indicator variables for block assignment will be included in the model as 
appropriate.  To account for multiple testing of primary outcomes of interest in response to treatment, a 
Hotelling’s T test will be used.  If this multivariate test is significant then individual outcomes will be 
compared between groups at an alpha level of 0.05.  Secondary outcomes (brain blood flow and blood 
pressure/arterial stiffness) will be assessed similarly with an adjusted alpha level of 0.0125.  All tertiary 
outcomes will be considered more exploratory for future hypothesis testing.  Given the design, treatment 
conditions and assessment protocols, we anticipate missing data (due to subject dropout, missed data 
collections, etc.) to be at least missing at random (MAR), if not missing completely at random (MCAR). 
Based on my pilot study, we do not expect the assigned treatment condition (NR or placebo) to influence 
whether a subject opts to continue with the study. Assuming missing data that are MAR or MCAR, a linear 
model or generalized linear model would yield valid inference. 
 
11. CONFIDENTIALITY 
 
Will participants be audiotaped, photographed or videotaped during this study? No 
 
How will subject identity be protected? Information obtained from this study will be kept strictly 
confidential. Subjects will not be individually identified, except by subject number, known only to the 
investigators. All data stored as paper files or digitally will be kept indefinitely. The paper files are stored in 
a locked cabinet. While the results of the research may be published, subjects’ names and identities will 
not be revealed. 

 
22 
 
Is there a Certificate of Confidentiality in place for this project?  (If so, please provide a copy). No. 
 
12. CONFLICT OF INTEREST 
(For information on disclosure reporting see: http://www.udel.edu/research/preparing/conflict.html ) 
 
Do you have a current conflict of interest disclosure form on file through UD Web forms? Yes 
 
 
Does this project involve a potential conflict of interest*? No. 
 
* As defined in the University of Delaware's Policies and Procedures ,a potential conflict of interest (COI) 
occurs when there is a divergence between an individual's private interests and his or her professional 
obligations, such that an independent observer might reasonably question whether the individual's 
professional judgment, commitment, actions, or decisions could be influenced by considerations of 
personal gain, financial or otherwise. 
 
 
13.  CONSENT and ASSENT 
 
__x__ Consent forms will be used and are attached for review (see Consent Template under Forms and 
Templates in IRBNet) 
 
14.  Other IRB Approval 
 
Has this protocol been submitted to any other IRBs? No 
 
If so, please list along with protocol title, number, and expiration date. 
 
15.  Supporting Documentation 
Please list all additional documents uploaded to IRBNet in support of this application. 
 
Informed Consent (subject) 
DSMB Charter 
CDR Survey 
Hopkins Verbal Learning Test 
Pre Consent Script 
Pre-Screening Questionnaire 
Recruitment opt out postcard 
Recruitment Letter 
MRI screening form 
Family history questionnaire 
Study Delegation Log 
Form 6. Physical Symptom Questionnaire 
REFERENCES 
 
1. 
Hughes, T. M. et al. Pulse wave velocity is associated with beta-amyloid deposition in the brains of 
very elderly adults. Neurology 81, 1711–1718 (2013). 
2. 
Hughes, T. M. et al. Arterial Stiffness and beta-Amyloid Progression in Nondemented Elderly 
Adults. Jama Neurology 71, 562–568 (2014). 
3. 
Pase, M. P. et al. Aortic Stiffness and the Risk of Incident Mild Cognitive Impairment and 
Dementia. Stroke 47, 2256–2261 (2016). 
4. 
Mitchell, G. F. et al. Arterial stiffness, pressure and flow pulsatility and brain structure and function: 
the Age, Gene/Environment Susceptibility - Reykjavik Study. Brain 134, 3398–3407 (2011). 
5. 
Nelson, L. & Tabet, N. Slowing the progression of Alzheimer’s disease; what works? Ageing Res 
Rev 23, 193–209 (2015). 

 
23 
6. 
Miller, S. L. & Wolfe, R. R. The danger of weight loss in the elderly. Journal of Nutrition Health & 
Aging 12, 487–491 (2008). 
7. 
DeVan, A. E. et al. Effects of sodium nitrite supplementation on vascular function and related small 
metabolite signatures in middle-aged and older adults. J Appl Physiol 120, 416–425 (2016). 
8. 
CA, D. et al. Vascular Health and Genetic Risk Affect Mild Cognitive Impairment Status and 4-
Year Stability: Evidence From the Victoria Longitudinal Study. LID - gbv043 [pii]. - J Gerontol B 
Psychol Sci Soc Sci.2015 Sep 11.pii: gbv043. 
9. 
Zuj, K. A. et al. Impaired cerebrovascular autoregulation and reduced CO2 reactivity after long 
duration spaceflight. American Journal of Physiology-Heart and Circulatory Physiology 302, 
H2592–H2598 (2012). 
10. 
Edwards, M. R., Devitt, D. L. & Hughson, R. L. Two-breath CO2 test detects altered dynamic 
cerebrovascular autoregulation and CO2 responsiveness with changes in arterial PCO2. American 
Journal of Physiology-Regulatory Integrative and Comparative Physiology 287, R627–R632 
(2004). 
11. 
Fraser, K. S. et al. Cerebral Hypoperfusion Is Exaggerated With an Upright Posture in Heart 
Failure Impact of Depressed Cardiac Output. Jacc-Heart Failure 3, 168–175 (2015). 
12. 
Robertson, A. D., Tessmer, C. F. & Hughson, R. L. Association between arterial stiffness and 
cerebrovascular resistance in the elderly. J Hum Hypertens 24, 190–196 (2010). 
13. 
Brar, I., Robertson, A. D. & Hughson, R. L. Increased central arterial stiffness and altered 
cerebrovascular haemodynamic properties in South Asian older adults. J Hum Hypertens 30, 309–
314 (2016). 
14. 
Stewart, J. M. et al. Postural neurocognitive and neuronal activated cerebral blood flow deficits in 
young chronic fatigue syndrome patients with postural tachycardia syndrome. American Journal of 
Physiology-Heart and Circulatory Physiology 302, H1185–H1194 (2012). 
15. 
Panerai, R. B., Eyre, M. & Potter, J. F. Multivariate modeling of cognitive-motor stimulation on 
neurovascular coupling: transcranial Doppler used to characterize myogenic and metabolic 
influences. American Journal of Physiology-Regulatory Integrative and Comparative Physiology 
303, R395–R407 (2012). 
16. 
Purkayastha, S. & Sorond, F. Transcranial Doppler Ultrasound: Technique and Application. Semin 
Neurol 32, 411–420 (2012). 
17. 
Trammell, S. A. J., Yu, L., Redpath, P., Migaud, M. E. & Brenner, C. Nicotinamide Riboside Is a 
Major NAD(+) Precursor Vitamin in Cow Milk. Journal of Nutrition 146, 957–963 (2016). 
18. 
Services, U. S. D. of H. and H., Administration, F. and D. & CDER, C. for D. E. and R. Guidance 
for Industry: Estimating the Maximum Safe Starting Dose in Initial Clinical Trials for Therapeutics 
in Adult Healthy Volunteers. (2005). 
19. 
DB, C., Crespo-Barreto, J. & CL, K. Safety assessment of nicotinamide riboside, a form of vitamin 
B3. - Hum Exp Toxicol.2016 Jan 20.pii: 0960327115626254. ePub Ahead, (2016). 
20. 
Khan, N. A. et al. Effective treatment of mitochondrial myopathy by nicotinamide riboside, a 
vitamin B3. EMBO Mol Med (2014). doi:emmm.201403943 [pii] 
21. 
Trammell, S. A. et al. Nicotinamide riboside is uniquely and orally bioavailable in mice and 
humans. Nat Commun 7, 12948 (2016). 
22. 
Martens, C. R. et al. Chronic nicotinamide riboside supplementation is well-Tolerated and elevates 
NAD+ in healthy middle-Aged and older adults. Nature Communications 9, (2018).