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A Biomarker to Detect Salt Sensitivity

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ClinicalTrials.gov Identifier: NCT03147170
Recruitment Status : Recruiting
First Posted : May 10, 2017
Last Update Posted : March 26, 2018
Sponsor:
Information provided by (Responsible Party):
University of Minnesota - Clinical and Translational Science Institute

Brief Summary:
The investigators are proposing that individuals with elevated levels of NT-proBNP are resistant to natriuretic peptides and are unable to handle sodium loads and maintain optimal blood pressure values.The investigators will test this hypothesis by comparing the blood pressure response to low and high salt diets in individuals with pre- or hypertension and who have normal or elevated levels of NT-proBNP. The investigators expect that blood pressure values in those with normal levels of NT-proBNP will not change with high salt diets, whereas, in those with elevated levels of NT-proBNP, blood pressure values will increase significantly when exposed to high salt diets.

Condition or disease Intervention/treatment
Hypertension Uncomplicated Pre Hypertension Diagnostic Test: High and low salt diets

Detailed Description:

Natriuretic peptides (NPs) are molecules that regulate blood pressure by inducing natriuresis and vasodilation. We have shown that higher baseline levels of NT-proBNP are associated with the development of hypertension and humans elevated NT-proBNP levels demonstrate resistance to the action of NPs and are unable to handle high dietary sodium loads. These findings have led us to propose that pre-hypertensive or newly diagnose hypertensive individuals, free of overt cardiovascular disease, who have elevated levels of NT-proBNP will experience a substantial rise in total body water and arterial blood pressure when exposed to a high sodium load. If this hypothesis holds true, then NT-proBNP could be used as a biological marker to identify salt sensitivity and for the prescription of low sodium diets to hypertensive individuals.

Research design: Individuals with physiological levels of NT-proBNP (40 - 90 pg/mL) and those with elevated levels (> 120 pg/mL) will be recruited to participate in a randomized crossover feeding study designed to treat patients with hypertension. A total of 8 participants, per group, will be exposed to two 10 days-phases of either a low sodium load (LS) of 50 mmol/day or a high sodium load (HS) of 250 mmol/day in random order and compare the blood pressure response to different sodium loads between the two NT-proBNP categories. Salt sensitivity is defined as a change in mean arterial blood pressure of ≥ 10% between the low and high sodium load. At the end of each phase, participants will be tested on a variety of anthropometric, blood and urinary measurements.

Variables measured: Total body water will be determined using bioelectrical impedance from Valhalla Scientific body comp scale®. Blood pressure monitors will be provided to each participant for measurement and record their own blood pressure twice daily for the duration of the study. In addition, at the end of each of the two sodium loading phases, trained personnel will measure BP three time using standard procedures, following an 8 hour fast and a 10 minute rest period at the clinic. Laboratory measurements. Blood and urine analysis will be performed at the start and end of each salt loading phase at the Advanced Research and Diagnostic Laboratory (ARDL). NT-proBNP will be measured using the Roche-Elecsys proBNP® (Roche Diagnostics, Indianapolis, IN). This method has a range of values that extends from 1 - 25000 pg/mL and the intra-assay precision is below 4% and the CV and interassay precision below 5% 21. Plasma BNP will be measured on a Siemens Advia Centaur instrument using a chemiluminescent immunoassay which has a minimal detection limit of 1.9 pg/mL and a CV of 3.4%. cGMP will be measured using a competitive enzyme immunoassay by Bio-Techne (Minneapolis, MN) intra essay CV is 7%. NT-proBNP will be measured using the Roche-Elecsys proBNP® (Roche Diagnostics, Indianapolis, IN). This method has a range of values that extends from 1 - 25000 pg/mL and the intra-assay precision is below 4% CV and inter-assay precision below 5% 21.

Anticipated results and future studies. Individuals with elevated NT-proBNP will have a significant increase in mean blood pressure and total body water (salt sensitive individuals) and a greater BNP/cGMP ratio when compared to those with physiological levels of NT-proBNP.

Power analysis shows that for a randomized cross-over study we would need 25 individuals per group for a 90% power.


Study Type : Observational
Estimated Enrollment : 30 participants
Observational Model: Case-Crossover
Time Perspective: Prospective
Official Title: Use of NT-proBNP as a Biomarker to Treat Salt Sensitive in Hypertensive Individuals
Actual Study Start Date : January 1, 2016
Estimated Primary Completion Date : June 30, 2018
Estimated Study Completion Date : June 30, 2018

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Sodium


Intervention Details:
  • Diagnostic Test: High and low salt diets
    Effects of high and low salt diets on blood pressure in individuals with normal and elevated levels of NT-proBNP


Primary Outcome Measures :
  1. Change in blood pressure [ Time Frame: 9 weeks ]
    Difference in blood pressure before and after diets periods and comparison between those with normal and elevated blood levels of NT-proBNP.


Secondary Outcome Measures :
  1. Ratio of BNP/cGMP [ Time Frame: 9 weeks ]
    Difference in BNP/cGMP before and after diets periods and comparison between those with normal and elevated blood levels of NT-proBNP.



Information from the National Library of Medicine

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Ages Eligible for Study:   30 Years to 75 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Sampling Method:   Non-Probability Sample
Study Population
Pre- or hypertensive individuals without chronic complications, between the ages of 30 and 75 years, not on blood pressure lowering medications.
Criteria

Inclusion Criteria:

  1. Systolic blood pressure > 120 and < 160 mmHg
  2. Diastolic blood pressure > 80 and < 100 mmHg
  3. Not on hypertensive medications
  4. NT-proBNP between 40 - 99 pg/mL (healthy levels)
  5. NT-proBNP > 120 pg/mL (elevated levels)

Exclusion Criteria:

  1. Physician reported diabetes or on insulin or oral hypoglycemic agents
  2. BMI > 40kg/m2
  3. Age < 30 or > 75 years
  4. Presence of cardiovascular disease or chronic kidney disease
  5. Chronic obstructive pulmonary disease or pulmonary arterial hypertension
  6. Aldosterone secreting disorder
  7. Estimated energy intake greater than 3400 calories
  8. Pregnancy
  9. Individuals with pacemakers

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03147170


Contacts
Contact: Otto A Sanchez, MD PhD 6156262119 sanc0050@umn.edu
Contact: Kathy Mischke 6126268904 misch016@umn.edu

Locations
United States, Minnesota
University of Minnesota Medical Center Recruiting
Minneapolis, Minnesota, United States, 55455
Sponsors and Collaborators
University of Minnesota - Clinical and Translational Science Institute
Investigators
Principal Investigator: Otto A Sanchez, MD PhD University of Minnesota - Clinical and Translational Science Institute

Responsible Party: University of Minnesota - Clinical and Translational Science Institute
ClinicalTrials.gov Identifier: NCT03147170     History of Changes
Other Study ID Numbers: 1512M81431
First Posted: May 10, 2017    Key Record Dates
Last Update Posted: March 26, 2018
Last Verified: March 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Undecided

Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No

Additional relevant MeSH terms:
Hypertension
Prehypertension
Vascular Diseases
Cardiovascular Diseases