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Effect of Dietary Sodium Intake on Vascular Endothelium

This study is ongoing, but not recruiting participants.
Sponsor:
ClinicalTrials.gov Identifier:
NCT01550315
First Posted: March 9, 2012
Last Update Posted: April 4, 2017
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Collaborators:
National Institutes of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Information provided by (Responsible Party):
Emily M. Garland, Vanderbilt University
  Purpose
The investigators will test the hypothesis that markers of vascular endothelial dysfunction will be exaggerated acutely with an extreme high sodium diet compared to an extreme low-sodium diet. The investigators will compare patients with postural orthostatic tachycardia (POTS) to healthy control subjects.

Condition Intervention
Postural Tachycardia Syndrome (POTS) Procedure: Pulsitile Arterial Tonometry (PAT) Protocol Device: Calf Blood Flow in Reactive Hyperemia (CBF-RH) Device: Evaluation of Forearm-Mediated Dilation

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: A Pilot Study of the Effect of Dietary Sodium Intake on Assessments of Vascular Endothelium

Resource links provided by NLM:


Further study details as provided by Emily M. Garland, Vanderbilt University:

Primary Outcome Measures:
  • RH-PAT Index [ Time Frame: On steady state (after 5 days) low and high sodium diets ]
    The primary analysis will involve a non-parametric, paired, Signed Rank test of RH-PAT between all subjects (POTS & control subjects) on the high sodium diet vs low sodium diet


Secondary Outcome Measures:
  • fasting glucose and insulin levels [ Time Frame: after steady state has been reached (>5 days) on low and high sodium diets ]
    Secondary analyses will include non-parametric paired comparisons between low sodium and high sodium diets of continuous outcome measures (outlined in section 7.3). Secondary comparisons might also assess differences in the dietary sodium induced changes between POTS patients and control subjects.


Estimated Enrollment: 50
Study Start Date: April 2012
Estimated Study Completion Date: March 2018
Estimated Primary Completion Date: March 2018 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: High Sodium - POTS & Controls
Subjects will receive a high sodium diet for 4-5 days prior to study day. Procedures include: blood work, urine collection, Pulsitile Arterial Tonometry (PAT), PAT analysis, Calf Blood Flow in Reactive Hyperemia (CBF-RH), & evaluation of forearm-mediated dilation.
Procedure: Pulsitile Arterial Tonometry (PAT) Protocol
  • A blood pressure cuff will be placed on one upper arm (study arm; non-dominant), while the contralateral arm will serve as a control (control arm).
  • RH-PAT probes will be placed on one finger (finger II, III, or IV) of each hand (same finger on both hands). The fingers on either side of the one with the probe will be separated using soft sponge rings.
  • Continuous recording of pulsatile blood volume responses from both hands will be initiated.
  • After a 10-min equilibration period, the blood pressure cuff on the study arm will be inflated to 60 mm Hg above systolic pressure for 5 min. The cuff will then be deflated to induce reactive hyperemia, PAT recording will be stopped.
Other Name: EndoPat
Device: Calf Blood Flow in Reactive Hyperemia (CBF-RH)
Calf blood flow (CBF) will be determined using venous occlusion plethysmography and calibrated mercury strain-gauges during reactive hyperemia after a 5 min of ischemia of the distal limb. Strain-gauges will be applied to the widest part of the non-dominant calf (~10 cm below patella). Participants will remain quietly supine for 10 min with legs elevated on foam pads above the right atrium to achieve stable baseline measurements of CBF. The venous occlusion cuff is inflated for 4 seconds at 8 seconds intervals, while monitoring the change in resistance in the system, pressure inside the measuring cuff, and 5-10 determinations are performed
Other Name: Hokansan strain guage venous plethysmography
Device: Evaluation of Forearm-Mediated Dilation
The arm will be kept extended and immobilized at heart level. Brachial artery diameter will be measured using a high resolution ultrasonography using a linear array probe with a 5 to 17 MHz frequency range. The brachial artery will be imaged in longitudinal sections, 5-10 cm proximal to placement of an occlusion cuff in the dominant forearm just below the antecubital fossa. The probe will be held with a stereotaxic holder with micrometer movement capabilities.
Other Name: Ultrasound
Low Sodium Diet (POTS & Controls)

Participants will consume a very low sodium diet (10 mEq/day) for 4-5 days prior to study day.

Procedures include: blood work, urine collection, Pulsitile Arterial Tonometry (PAT), PAT analysis, Calf Blood Flow in Reactive Hyperemia (CBF-RH), & evaluation of forearm-mediated dilation.

Procedure: Pulsitile Arterial Tonometry (PAT) Protocol
  • A blood pressure cuff will be placed on one upper arm (study arm; non-dominant), while the contralateral arm will serve as a control (control arm).
  • RH-PAT probes will be placed on one finger (finger II, III, or IV) of each hand (same finger on both hands). The fingers on either side of the one with the probe will be separated using soft sponge rings.
  • Continuous recording of pulsatile blood volume responses from both hands will be initiated.
  • After a 10-min equilibration period, the blood pressure cuff on the study arm will be inflated to 60 mm Hg above systolic pressure for 5 min. The cuff will then be deflated to induce reactive hyperemia, PAT recording will be stopped.
Other Name: EndoPat
Device: Calf Blood Flow in Reactive Hyperemia (CBF-RH)
Calf blood flow (CBF) will be determined using venous occlusion plethysmography and calibrated mercury strain-gauges during reactive hyperemia after a 5 min of ischemia of the distal limb. Strain-gauges will be applied to the widest part of the non-dominant calf (~10 cm below patella). Participants will remain quietly supine for 10 min with legs elevated on foam pads above the right atrium to achieve stable baseline measurements of CBF. The venous occlusion cuff is inflated for 4 seconds at 8 seconds intervals, while monitoring the change in resistance in the system, pressure inside the measuring cuff, and 5-10 determinations are performed
Other Name: Hokansan strain guage venous plethysmography
Device: Evaluation of Forearm-Mediated Dilation
The arm will be kept extended and immobilized at heart level. Brachial artery diameter will be measured using a high resolution ultrasonography using a linear array probe with a 5 to 17 MHz frequency range. The brachial artery will be imaged in longitudinal sections, 5-10 cm proximal to placement of an occlusion cuff in the dominant forearm just below the antecubital fossa. The probe will be held with a stereotaxic holder with micrometer movement capabilities.
Other Name: Ultrasound

Detailed Description:

The study will involve a crossover design in which each subject will be assessed (as below) while on a very low-sodium (10 mEq/day) diet compared with a very high-sodium diet. These acute dietary interventions will be part of the parent study ("Dietary Salt in Postural Tachcyardia Syndrome" funded by R01 HL102387) for 4-5 days at the time of the study. Dietary success will be assessed using a 24h urine for sodium and creatinine as a part of the parent study.

Blood will be drawn and collected in a fasting state for future assay and analysis of the following tests:

  • Glucose, Insulin (glucose impairment, insulin resistance)
  • Fasting lipid profile
  • C-Reactive Protein (hsCRP) (inflammatory state)
  • Inflammatory cytokines (inflammatory state)
  • aliquots (future analysis)

Pulsitile Arterial Tonometry (PAT) Protocol Calf Blood Flow in Reactive Hyperemia (CBF-RH) - venous occlusion plethysmography Evaluation of Forearm-Mediated Dilation

  Eligibility

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Subjects will be enrolled in the parent study "Dietary Salt in Postural Tachcyardia Syndrome" funded by R01 HL102387 Postural Tachycardia Syndrome
  • Diagnosed with postural tachycardia syndrome by the Vanderbilt Autonomic Dysfunction Center
  • Subjects will be enrolled in the parent study "Dietary Salt in Postural Tachcyardia Syndrome" funded by R01 HL102387
  • Postural Tachycardia Syndrome
  • Diagnosed with postural tachycardia syndrome by the Vanderbilt Autonomic Dysfunction Center
  • Increase in heart rate ≥30 beats/min with position change from supine to standing (10 minutes)
  • Chronic symptoms consistent with POTS that are worse when upright and get better with recumbence Control Subjects
  • Healthy, non-obese, non-smokers without orthostatic tachycardia
  • Selected to match profiles of POTS patients (gender, age)
  • Not using vasoactive medication
  • Age between 18-60 years
  • Male and female subjects are eligible.
  • Able and willing to provide informed consent

Exclusion Criteria:

  • Overt cause for postural tachycardia (such as acute dehydration)
  • Inability to give, or withdrawal of, informed consent
  • Pregnant
  • Other factors which in the investigator's opinion would prevent the subject from completing the protocol.
  Contacts and Locations
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): NCT01550315


Locations
United States, Tennessee
Vanderbilt University Medical Center
Nashville, Tennessee, United States, 37232
Sponsors and Collaborators
Vanderbilt University
National Institutes of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Investigators
Principal Investigator: Satish R Raj, MD MSCI Vanderbilt University
  More Information

Publications:
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Böger RH, Bode-Böger SM, Szuba A, Tsao PS, Chan JR, Tangphao O, Blaschke TF, Cooke JP. Asymmetric dimethylarginine (ADMA): a novel risk factor for endothelial dysfunction: its role in hypercholesterolemia. Circulation. 1998 Nov 3;98(18):1842-7.
Mangin EL Jr, Kugiyama K, Nguy JH, Kerns SA, Henry PD. Effects of lysolipids and oxidatively modified low density lipoprotein on endothelium-dependent relaxation of rabbit aorta. Circ Res. 1993 Jan;72(1):161-6.
Vergnani L, Hatrik S, Ricci F, Passaro A, Manzoli N, Zuliani G, Brovkovych V, Fellin R, Malinski T. Effect of native and oxidized low-density lipoprotein on endothelial nitric oxide and superoxide production : key role of L-arginine availability. Circulation. 2000 Mar 21;101(11):1261-6.
Landmesser U, Merten R, Spiekermann S, Büttner K, Drexler H, Hornig B. Vascular extracellular superoxide dismutase activity in patients with coronary artery disease: relation to endothelium-dependent vasodilation. Circulation. 2000 May 16;101(19):2264-70.
Quyyumi AA, Dakak N, Andrews NP, Husain S, Arora S, Gilligan DM, Panza JA, Cannon RO 3rd. Nitric oxide activity in the human coronary circulation. Impact of risk factors for coronary atherosclerosis. J Clin Invest. 1995 Apr;95(4):1747-55.
Appel LJ, Frohlich ED, Hall JE, Pearson TA, Sacco RL, Seals DR, Sacks FM, Smith SC Jr, Vafiadis DK, Van Horn LV. The importance of population-wide sodium reduction as a means to prevent cardiovascular disease and stroke: a call to action from the American Heart Association. Circulation. 2011 Mar 15;123(10):1138-43. doi: 10.1161/CIR.0b013e31820d0793. Epub 2011 Jan 13.
Meneton P, Jeunemaitre X, de Wardener HE, MacGregor GA. Links between dietary salt intake, renal salt handling, blood pressure, and cardiovascular diseases. Physiol Rev. 2005 Apr;85(2):679-715. Review.
MENEELY GR, BALL CO. Experimental epidemiology of chronic sodium chloride toxicity and the protective effect of potassium chloride. Am J Med. 1958 Nov;25(5):713-25.
Strazzullo P, D'Elia L, Kandala NB, Cappuccio FP. Salt intake, stroke, and cardiovascular disease: meta-analysis of prospective studies. BMJ. 2009 Nov 24;339:b4567. doi: 10.1136/bmj.b4567. Review.
Dishy V, Sofowora GG, Imamura H, Nishimi Y, Xie HG, Wood AJ, Stein CM. Nitric oxide production decreases after salt loading but is not related to blood pressure changes or nitric oxide-mediated vascular responses. J Hypertens. 2003 Jan;21(1):153-7.
Fujiwara N, Osanai T, Kamada T, Katoh T, Takahashi K, Okumura K. Study on the relationship between plasma nitrite and nitrate level and salt sensitivity in human hypertension : modulation of nitric oxide synthesis by salt intake. Circulation. 2000 Feb 29;101(8):856-61.
Kuvin JT, Patel AR, Sliney KA, Pandian NG, Sheffy J, Schnall RP, Karas RH, Udelson JE. Assessment of peripheral vascular endothelial function with finger arterial pulse wave amplitude. Am Heart J. 2003 Jul;146(1):168-74.
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Meredith IT, Currie KE, Anderson TJ, Roddy MA, Ganz P, Creager MA. Postischemic vasodilation in human forearm is dependent on endothelium-derived nitric oxide. Am J Physiol. 1996 Apr;270(4 Pt 2):H1435-40.
Dakak N, Husain S, Mulcahy D, Andrews NP, Panza JA, Waclawiw M, Schenke W, Quyyumi AA. Contribution of nitric oxide to reactive hyperemia: impact of endothelial dysfunction. Hypertension. 1998 Jul;32(1):9-15.
Higashi Y, Sasaki S, Nakagawa K, Matsuura H, Kajiyama G, Oshima T. A noninvasive measurement of reactive hyperemia that can be used to assess resistance artery endothelial function in humans. Am J Cardiol. 2001 Jan 1;87(1):121-5, A9.
Wilkinson IB, Qasem A, McEniery CM, Webb DJ, Avolio AP, Cockcroft JR. Nitric oxide regulates local arterial distensibility in vivo. Circulation. 2002 Jan 15;105(2):213-7.
Noon JP, Haynes WG, Webb DJ, Shore AC. Local inhibition of nitric oxide generation in man reduces blood flow in finger pulp but not in hand dorsum skin. J Physiol. 1996 Jan 15;490 ( Pt 2):501-8.
Nohria A, Gerhard-Herman M, Creager MA, Hurley S, Mitra D, Ganz P. Role of nitric oxide in the regulation of digital pulse volume amplitude in humans. J Appl Physiol (1985). 2006 Aug;101(2):545-8. Epub 2006 Apr 13.
Thijssen DH, Black MA, Pyke KE, Padilla J, Atkinson G, Harris RA, Parker B, Widlansky ME, Tschakovsky ME, Green DJ. Assessment of flow-mediated dilation in humans: a methodological and physiological guideline. Am J Physiol Heart Circ Physiol. 2011 Jan;300(1):H2-12. doi: 10.1152/ajpheart.00471.2010. Epub 2010 Oct 15. Review.
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Responsible Party: Emily M. Garland, Research Associate Professor of Medicine, Vanderbilt University
ClinicalTrials.gov Identifier: NCT01550315     History of Changes
Other Study ID Numbers: 111577
R01HL102387 ( U.S. NIH Grant/Contract )
First Submitted: March 2, 2012
First Posted: March 9, 2012
Last Update Posted: April 4, 2017
Last Verified: April 2017

Keywords provided by Emily M. Garland, Vanderbilt University:
POTS
endothelial function
high salt vs low salt diet
PAT protocol
Calf blood flow
forearm mediated dilation

Additional relevant MeSH terms:
Tachycardia
Postural Orthostatic Tachycardia Syndrome
Arrhythmias, Cardiac
Heart Diseases
Cardiovascular Diseases
Pathologic Processes
Orthostatic Intolerance
Primary Dysautonomias
Autonomic Nervous System Diseases
Nervous System Diseases


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