Diagnosing Natriuretic Peptide Deficiency: A Pilot Study
Phase: PHASE1
Conditions: Healthy, Lean
Sponsor: Vanderbilt University Medical Center

 
Protocol Version #: 3 
 
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Protocol Date: 08/18/2017 
 
 
 
 
 
 
 
 
Diagnosing Natriuretic Peptide Deficiency:  
A Pilot Study 
 
 
 
Katherine N. Bachmann, M.D. 
Instructor, Dept. of Medicine 
Division of Diabetes, Endocrinology, and Metabolism 
Vanderbilt University Medical Center 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Table of Contents: 
 

 
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Protocol Date: 08/18/2017 
Study Schema 
1.0 
Background 
2.0 
Rationale and Specific Aims 
3.0 
Animal Studies and Previous Human Studies 
4.0 
Inclusion/Exclusion Criteria 
5.0 
Enrollment/Randomization 
6.0 
Study Procedures 
-Figure: Study Design 
-Table: CRC Protocol Overview 
7.0 
Risks of Investigational Agents/Devices (side effects) 
8.0 
Reporting of Adverse Events or Unanticipated Problems involving Risk to 
Participants or Others 
9.0 
Study Withdrawal/Discontinuation 
10.0 Statistical Considerations 
11.0 Privacy/Confidentiality Issues 
12.0 Follow-up and Record Retention 
13.0 References 
 
 

 
Protocol Version #: 3 
 
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Protocol Date: 08/18/2017 
1.0 
Background 
 
The cardiac natriuretic peptide (NP) system may protect against the development of 
cardiometabolic risk. 
 
 
 
 
 
  
 
 
 
 
 
 
 
  
 
2.0 
Rationale and Specific Aims 
 
NP hormones may protect against cardiometabolic risk. 
 
 
 
 
  
 
Studies in animals suggest that glucocorticoids potently stimulate NP production. There are 
limited studies in humans showing that glucocorticoids stimulate NP production;3 however, the 
NP response specifically to dexamethasone, the glucocorticoid which has been shown in animal 
data to potently stimulate NP production, has not been defined in humans. Moreover, the range 
of normal responses to glucocorticoids in healthy individuals is not well-defined. 
 
 
 
 
 
 
  
 
The goal of the proposed project is to generate preliminary data that will be used to 
develop power calculations, inform cutoff ranges, and inform the timing of the NP response 
for larger subsequent studies 
.” In 
this pilot study, we will quantify the distribution of NP responses and characterize the time 
course of NP responses to a highly standardized dosing protocol of dexamethasone. This pilot 
study will allow us to determine the range and standard deviation of NP responses to 
dexamethasone in healthy controls.  
 
Aim: To determine the range of distribution and time course of NP responses to a single dose of 
dexamethasone IV 4 mg in healthy lean individuals. 

 
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Protocol Date: 08/18/2017 
Hypothesis: Determination of the NP responses (the range and time course of changes in NP 
levels) to dexamethasone in 11 healthy individuals will inform the time course and frequency of 
blood sampling in a definitive prospective study 
 
, as well as enable us to perform a sample size calculation for 
a definitive prospective study. 
 
3.0 
Animal Studies and Previous Human Studies 
 
Studies in animals suggest that glucocorticoids potently stimulate NP production. Administration 
of dexamethasone to rats caused an increase in atrial natriuretic peptide (ANP) expression in 
the heart, where ANP is produced.4 
 
 
.5  
 
There are limited studies in humans showing that glucocorticoids stimulate NP production.  
 
 
 
 
 
 
.  
 
4.0 
Inclusion/Exclusion Criteria 
 
Inclusion Criteria:  
 
Men and women ages 18-50 years  
 
BMI 18.5 to <25 kg/m2  
 
Exclusion Criteria:  
 
Current use of glucocorticoids, or significant use of systemic glucocorticoids for an 
extended period of time during the prior 6 months 
 
Current use of antihypertensive medications  
 
Current use of metformin, or any antidiabetic medications (which could affect glucose 
and insulin levels) 
 
Current use of medications known to affect dexamethasone metabolism, including 
phenytoin, rifampin, carbamazepine, troglitazone, and barbiturates 
 
Active, clinically significant infection at time of visit 
 
History of adrenal insufficiency or Cushing’s syndrome 
 
Prior or current cardiovascular disease, renal disease, or liver disease 
 
Diabetes mellitus, pre-diabetes, impaired fasting glucose, or impaired glucose tolerance 
 
Atrial fibrillation 

 
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 
Bleeding disorder or anemia 
 
Elevated LFTs > 2 times upper limit of normal 
 
eGFR < 60 ml/min  
 
HbA1c > 5.7 
 
Abnormal sodium or potassium level 
 
Positive pregnancy test, women of child-bearing age not practicing birth control, women 
who are breastfeeding 
 
 
5.0 
Enrollment/Randomization 
 
Subjects will be recruited via the Vanderbilt Broadcast email system 
(research.notifications@vanderbilt.edu).  
 
ResearchMatch.org will be utilized as a recruitment tool for this protocol.  ResearchMatch.org is 
a national electronic, web-based recruitment tool that was created through the Clinical & 
Translational Science Awards Consortium in 2009 and is maintained at Vanderbilt University as 
an IRB-approved data repository (see IRB #090207).   
 
 
6.0 
Study Procedures 
 
Screening Visit 
 
After informed consent has been obtained, the subject’s medical history and medications will be 
discussed and documented. A physical exam, including measurement of height, weight, and 
vital signs, will be performed.  Blood will be collected for a comprehensive metabolic panel, 
CBC, and Hemoglobin A1c, and a urine pregnancy test will be done on female subjects of child-
bearing age. Inclusion/exclusion criteria will be reviewed to confirm that the subject meets 
study eligibility requirements.  
 
Eligible subjects who wish to participate in the study will be scheduled for 4 additional 
outpatient visits at the CRC. Subjects will be instructed to subjects to continue their habitual 
sodium intake for several days prior to the study and throughout the study. The Study design 
and CRC Protocol Overview are shown in the Figure and Table below, respectively.

 
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Figure: Study Design 
 
 
 
 
 
 
 
 
 
 
 
 
Table: CRC Protocol Overview – Day 1 
Time 
Procedures 
NP levels 
RAAS measurements 
Urine 
Glucose metabolism 
markers 
7:00 AM 
(approx.) 
 
 
IV placement; 
Lay supine for 
60 minutes 
before baseline 
blood collection 
 
Baseline collection after 
lying supine for 60 min 
Baseline collection after lying 
supine for 60 min 
Baseline 
collection 
Baseline collection after 
lying supine for 60 min 
 
8:15 AM-
4:15 PM 
(approx.) 
 
 
Inject 
dexamethasone  
 
 
Q 30 min for first 3 hours; 
Then Q 60 minutes for 
next 5 hours 
Q 30 min for first 3 hours; 
Then Q 60 minutes for next 5 
hours 
Q 120 
min 
Q 30 min for first 3 hours; 
Then Q 60 minutes for 
next 5 hours 
 
 
CRC Visit - Day 1 
 
Subjects will arrive at the CRC in the early morning (around 7 AM). Subjects will have fasted for 
at least 8 hours. Upon arrival to CRC, subjects will provide a urine sample. A urine pregnancy 
test will be done on female subjects of child-bearing age.  Immediately after urinating, subjects 
will be instructed to lay in a supine position, and they will remain in this supine position during 
the remainder of the study visit, including during voiding (subjects will be instructed to use a 
bedpan or urinal jug when voiding, as they must remain supine). Supine positioning is crucial 
for reliable evaluation of RAAS measurements. One peripheral IV will be placed, which will be 
used for blood draws. Normal (0.9%) Saline (NS) will be infused at a rate of approximately 10 
ml/hr to keep the IV line open and ensure successful subsequent blood draws. 
 
After the subjects have been lying supine for 60 minutes, a baseline blood sample will be 
collected for NP, RAAS measurements (aldosterone, plasma renin activity), cortisol, basic 
chemistries, and markers of glucose metabolism (glucose, insulin level). Immediately 
afterwards, subjects will receive an intravenous injection of dexamethasone 4 mg. Blood will be 
collected every 30 minutes during the first 3 hours, and then every 60 minutes during the 
following 5 hours. Additional blood, at each time point, may be used to run other tests, 
including dexamethasone levels to help determine clearance rate of dexamethasone which may 
Day 1 Visit:
Days 2-4 Visits:
Early AM- dexamethasone injection
Blood and urine collections
during the next 8 hours
1 blood draw each morning 
(24, 48, and 72 hours after 
dexamethasone injection on 
Day 1)
Screening 
Visit

 
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differ between individuals.  Subjects will remain fasting until 8 hours after the dexamethasone 
injection. At this time (8 hours after the dexamethasone injection), the study procedures for 
Day 1 will conclude.  A meal will be provided at the completion of the visit.  
 
All urine produced during the visit will be collected and some saved for future analysis. Subjects 
will be asked to produce a urine sample approximately every 120 minutes throughout the study 
visit; however, if the subject is unable to void at the pre-specified time points, urine will be 
collected when the subject is able to void and the time that the urine was produced will be 
recorded. Vital signs will be recorded every 30 minutes. During the visit, a dietician will speak 
with the subject and assess the subject’s sodium intake during the 24-hours prior to the visit.  
 
CRC Visits- Days 2, 3, and 4 
Subjects will present to the CRC for brief visits on Days 2, 3, and 4.  Subjects will arrive after 
having fasted for at least 8 hours. There will be one blood draw at each visit; the blood will be 
collected approximately 24 hours after, 48 hours after, and 72 hours after the dexamethasone 
injection was given on Day 1. Subjects will provide one spot urine collection at each visit.  
 
 
Other study procedures 
Subjects will be asked to discontinue use of NSAIDS, decongestants, and cold medicines one 
week prior to study and to remain off these agents until the study is completed.  
 
Biomarkers 
Blood and urine samples will be coded for subject confidentiality.  Measurements of BNP, ANP, 
and their pro-peptides will be performed at Vanderbilt University Medical Center in the 
Cardiology Core Lab. Excess blood and urine samples will be frozen and stored for possible 
future investigation. 
 
DNA Sample 
For those subjects who provide consent, a DNA sample will be collected, frozen and stored to 
allow for future potential investigations of NP system by genotype. Samples will be coded for 
subject confidentiality. 
 
 
 
7.0 
Risks of Investigational Agents/Devices (side effects) 
 
General:  Risks related to overnight fasting include hypovolemia. Thus, subjects will have 
baseline blood pressure measured upon arrival at the CRC. The risks associated with 
phlebotomy in healthy individuals are minimal. Volume depletion and anemia are possible risks 
of phlebotomy; these risks will be minimized by excluding individuals with known anemia or 
other significant medical problems that may predispose to anemia, as well as by checking a CBC 
at the screening visit and by monitoring blood pressure at the study visits. Risks related to the 
placement of the peripheral intravenous lines include hematoma formation and phlebitis. In 
addition, there is a potential risk of hypoglycemia while fasting overnight and during the 
morning until study procedures are completed. The risk of hypoglycemia in healthy individuals 
while fasting for this amount of time is low. Subjects will be provided a meal at the conclusion 
of the infusion.  

 
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Protocol Date: 08/18/2017 
Dexamethasone: Potential adverse reactions to dexamethasone include infection, hypertension, 
increased blood glucose, headache, fatigue, emotional lability, increased appetite, nausea, 
abdominal discomfort, drug hypersensitivity, and increased bone turnover or bone loss. 
However, these potential adverse reactions are much more likely to occur with extended or 
chronic use of dexamethasone, and are much less likely with a single dose of dexamethasone. 
In the current study, we are giving a single IV dose of dexamethasone, which has a rapid half-
life and thus is cleared rapidly from the body and therefore would be less likely to cause 
adverse reactions than with chronic use of dexamethasone.  
 
8.0 
Reporting of Adverse Events or Unanticipated Problems involving Risk to 
Participants or Others 
 
Adverse events will be reported to the IRB per Vanderbilt University Medical Center IRB policy. 
 
9.0 
Study Withdrawal/Discontinuation 
 
Subjects may withdraw from the study at any time and should notify study personnel if they 
wish to withdraw from the study. Subjects may request their biological samples to be destroyed 
at any time. However, any data or biological samples that have already been used for research 
cannot be destroyed. Subjects may be discontinued from the study at the discretion of the 
investigators’ (possible reasons listed below). Subjects will receive financial compensation for 
the visits that they complete. 
 
Possible reasons for withdrawal/discontinuation from study include, but are not limited to: 
 
Development of an active infection at the time of the Day 1 visit 
 
Noncompliance with treatment or procedures 
 
Decision by participant/participant withdraws consent 
 
Lost to follow-up 
 
Starting a medication mentioned in exclusion criteria (glucocorticoids other than what is 
prescribed in the study, antihypertensive medications, metformin, or any antidiabetic 
medications, any medications known to affect dexamethasone metabolism) 
 
Development of a significant medical condition specified in the exclusion criteria 
 
In female subjects, becoming pregnant during study 
 
Significant adverse event deemed by investigator to preclude continued participation 
 
 
10.0 Statistical Considerations 
 
The two primary endpoints will be the NT-proANP trajectory (NT-proANP levels across time) 
and NT-proBNP trajectory (NT-proBNP levels across time). We will also measure ANP and BNP 
to fully define their kinetics. The descriptive statistics, such as mean, median, range, and 
standard deviation, will be examined at each time point. The mean levels of the endpoints will 
be plotted by time points to visualize their changes. The null hypotheses are that NT-proANP 
will not change over time (slope of NT-proANP trajectory= 0) and that NT-proBNP will not 

 
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Protocol Date: 08/18/2017 
change over time (slope of NT-proBNP trajectory= 0). For our analysis, we will use restricted 
maximum likelihood (REML)-based mixed effect model analyses for the two primary endpoints: 
1) NT-proANP trajectory as the outcome and time points as covariates, and 2) NT-proBNP 
trajectory as the outcome and timepoints as covariates. 
 
11.0 Privacy/Confidentiality Issues 
 
Strict confidentiality will be maintained to the fullest extent by the research team, including 
keeping all data in a secure location. All specimens will be coded after they are obtained and 
the code key kept in a secure location.  Blood samples will be coded anonymously to remain 
confidential and identifiers will be kept in a separate, secure location.   Samples may be shared 
with third parties outside of Vanderbilt for future testing but will remain anonymous to the 
recipient.  Subjects may contact the principal investigator at any time to request that samples 
be destroyed. 
 
 
12.0 Follow-up and Record Retention 
 
Anticipated study duration is 6 months. Research data will be maintained by the PI after study 
closure. After study closure, research data will be maintained for a minimum of 6 years and 
possibly indefinitely. Data will be stored on the Vanderbilt University computer network in a 
password-protected database. Only members of the study team will have access. Pertinent 
paper documentation will be kept in a locked office and only study personnel will have access. 
Only personnel directly involved with the study will have access to source data and the 
electronic database. 

 
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13.0 References 
 
1. 
Khan AM, Cheng S, Magnusson M, et al. Cardiac natriuretic peptides, obesity, and insulin 
resistance: evidence from two community-based studies. J Clin Endocrinol Metab 2011;96:3242-
9. 
2. 
Wang TJ, Larson MG, Keyes MJ, Levy D, Benjamin EJ, Vasan RS. Association of plasma 
natriuretic peptide levels with metabolic risk factors in ambulatory individuals. Circulation 
2007;115:1345-53. 
3. 
Saxenhofer H, Angst M, Weidmann P, Shaw SG, Ferrier C. Corticosteroid-induced 
stimulation of atrial natriuretic peptide in man. Acta Endocrinol (Copenh) 1988;118:179-86. 
4. 
Dananberg J, Grekin RJ. Corticoid regulation of atrial natriuretic factor secretion and 
gene expression. Am J Physiol 1992;263:H1377-81. 
5. 
Gardner DG, Hane S, Trachewsky D, Schenk D, Baxter JD. Atrial natriuretic peptide 
mRNA is regulated by glucocorticoids in vivo. Biochem Biophys Res Commun 1986;139:1047-
54.