Renal Salt Handling in Postural Tachycardia Syndrome Following Dietary Dopa Administration

This study has been completed.
Sponsor:
Information provided by (Responsible Party):
Emily M. Garland, Vanderbilt University
ClinicalTrials.gov Identifier:
NCT01064739
First received: February 5, 2010
Last updated: August 1, 2013
Last verified: August 2013
  Purpose

The purpose of this study is to learn how plants can play a role in gain/loss of sodium in the urine and in the regulation of blood pressure. Dopamine is a chemical mostly present in the brain and kidneys which assists in regulation of the body's salts (sodium and potassium). Fava beans contain a lot of the chemical that increases the production of dopamine by the kidneys.

The purpose of these studies is to characterize the diuretic effects of dietary catecholamine sources in healthy individuals. Specific aims are:

  1. To determine the effect of dietary dopa sources on plasma and urinary catecholamines.
  2. To investigate the capacity of botanical dopaminergic agents (fava beans) to induce natriuresis in a short term study.
  3. To provide preliminary data on the effects of dietary dopa on heart rate and blood pressure.

In these studies, we will test the null hypothesis (Ho) that urinary sodium excretion will not differ in healthy volunteers after consumption of a fixed-sodium study diet and the study diet plus fava beans.


Condition Intervention Phase
Healthy Volunteers
Dietary Supplement: Fava beans
Other: Fixed Sodium Diet
Phase 0

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: Open Label
Official Title: Renal Salt Handling in Postural Tachycardia Syndrome Following Dietary Dopa Administration

Resource links provided by NLM:


Further study details as provided by Vanderbilt University:

Primary Outcome Measures:
  • Plasma Dopa 1 hr After Breakfast [ Time Frame: Plasma samples collected 1 hour after breakfast on both study days. ] [ Designated as safety issue: No ]
    Subjects consumed the standard fixed sodium diet for at least two days prior to study and on study day one during an inpatient stay in the Vanderbilt Clinical Research Center. On study day two, participants ate 100 g of puréed fava beans and pods with study diet at breakfast (0800hr) and lunch (1200hr). Blood was sampled for catechol assays before and at 1, 2, 4 and 6 hours after breakfast. Plasma dopa 1 hour after breakfast was specified as a primary outcome. Other catechols (dihydroxyphenylglycol, norepinephrine, epinephrine, dopamine, dihydroxyphenylacetic acid) and other time points (2, 3, 4, 6hr after breakfast) are non-primary outcomes.

  • Urinary Dopa [ Time Frame: 4-8 hours after breakfast ] [ Designated as safety issue: No ]
    Urinary dopa excreted 4-8 hours after breakfast was specified as a primary outcome. Other catechols (dihydroxyphenylglycol, norepinephrine, epinephrine, dopamine, dihydroxyphenylacetic acid) and other time points (0-4 hr, 8-12 hr after breakfast) are non-primary outcomes.

  • Urinary Sodium [ Time Frame: 4 to 8 hours after breakfast ] [ Designated as safety issue: No ]
    Urinary sodium excreted 4-8 hours after breakfast was designated as a primary outcome. Other urine samples (0-4 hr, 8-12 hr after breakfast) are considered as non-primary outcomes.


Secondary Outcome Measures:
  • Plasma Dopa 2 Hrs After Breakfast [ Time Frame: Plasma samples collected 2 hours after breakfast on both study days. ] [ Designated as safety issue: No ]
    Subjects consumed the standard fixed sodium diet for at least two days prior to study and on study day one during an inpatient stay in the Vanderbilt Clinical Research Center. On study day two, participants ate 100 g of puréed fava beans and pods with study diet at breakfast (0800hr) and lunch (1200hr). Blood was sampled for catechol assays before and at 1, 2, 4 and 6 hours after breakfast. Plasma dopa 1 hour after breakfast was specified as a primary outcome. Other catechols (dihydroxyphenylglycol, norepinephrine, epinephrine, dopamine, dihydroxyphenylacetic acid) and other time points (2, 3, 4, 6hr after breakfast) are non-primary outcomes.

  • Plasma Dopa 4 Hrs After Breakfast [ Time Frame: Plasma samples collected 4 hours after breakfast on both study days. ] [ Designated as safety issue: No ]
    Subjects consumed the standard fixed sodium diet for at least two days prior to study and on study day one during an inpatient stay in the Vanderbilt Clinical Research Center. On study day two, participants ate 100 g of puréed fava beans and pods with study diet at breakfast (0800hr) and lunch (1200hr). Blood was sampled for catechol assays before and at 1, 2, 4 and 6 hours after breakfast. Plasma dopa 1 hour after breakfast was specified as a primary outcome. Other catechols (dihydroxyphenylglycol, norepinephrine, epinephrine, dopamine, dihydroxyphenylacetic acid) and other time points (2, 3, 4, 6hr after breakfast) are non-primary outcomes.

  • Plasma Dopa 6 Hrs After Breakfast [ Time Frame: Plasma samples collected 6 hours after breakfast on both study days. ] [ Designated as safety issue: No ]
    Subjects consumed the standard fixed sodium diet for at least two days prior to study and on study day one during an inpatient stay in the Vanderbilt Clinical Research Center. On study day two, participants ate 100 g of puréed fava beans and pods with study diet at breakfast (0800hr) and lunch (1200hr). Blood was sampled for catechol assays before and at 1, 2, 4 and 6 hours after breakfast. Plasma dopa 1 hour after breakfast was specified as a primary outcome. Other catechols (dihydroxyphenylglycol, norepinephrine, epinephrine, dopamine, dihydroxyphenylacetic acid) and other time points (2, 3, 4, 6hr after breakfast) are non-primary outcomes.

  • Plasma Norepinephrine [ Time Frame: 1 hour after breakfast on both study days. ] [ Designated as safety issue: No ]
    Plasma norepinephrine 1 hour after breakfast

  • Plasma Norepinephrine [ Time Frame: 2 hours after breakfast on both study days. ] [ Designated as safety issue: No ]
    Plasma norepinephrine 2 hours after breakfast

  • Plasma Norepinephrine [ Time Frame: 4 hours after breakfast on both study days. ] [ Designated as safety issue: No ]
    Plasma norepinephrine 4 hours after breakfast

  • Plasma Norepinephrine [ Time Frame: 6 hours after breakfast on both study days. ] [ Designated as safety issue: No ]
    Plasma norepinephrine 6 hours after breakfast

  • Plasma Dopamine [ Time Frame: 1 hour after breakfast ] [ Designated as safety issue: No ]
    Plasma dopamine 1 hour after breakfast

  • Plasma Dopamine [ Time Frame: 2 hours after breakfast on both study days. ] [ Designated as safety issue: No ]
    Plasma dopamine 2 hours after breakfast

  • Plasma Dopamine [ Time Frame: 4 hours after breakfast on both study days. ] [ Designated as safety issue: No ]
    Plasma dopamine 4 hours after breakfast

  • Plasma Dopamine [ Time Frame: Plasma samplesPlasma dopamine 6 hours after breakfast on both study days. ] [ Designated as safety issue: No ]
    Plasma dopamine 6 hours after breakfast

  • Urinary Dopa [ Time Frame: 0-4 hours after breakfast ] [ Designated as safety issue: No ]
    Urinary dopa excreted 4-8 hours after breakfast was specified as a primary outcome. Other time points (0-4 hr, 8-12 hr after breakfast) are non-primary outcomes.

  • Urinary Dopa [ Time Frame: 8-12 hours after breakfast ] [ Designated as safety issue: No ]
    Urinary dopa excreted 4-8 hours after breakfast was specified as a primary outcome. Other time points (0-4 hr, 8-12 hr after breakfast) are non-primary outcomes.

  • Urinary Dopamine [ Time Frame: 0 to 4 hours after breakfast ] [ Designated as safety issue: No ]
    Urinary dopamine excreted 0 to 4 hours after breakfast

  • Urinary Dopamine [ Time Frame: 4 to 8 hours after breakfast ] [ Designated as safety issue: No ]
    Urinary dopamine excreted 4 to 8 hours after breakfast

  • Urinary Dopamine [ Time Frame: 8 to 12 hours after breakfast ] [ Designated as safety issue: No ]
    Urinary dopamine excreted 8 to 12 hours after breakfast

  • Urinary Norepinephrine [ Time Frame: 0 to 4 hours after breakfast ] [ Designated as safety issue: No ]
    Urinary norepinephrine excreted 0-4 hours after breakfast

  • Urinary Norepinephrine [ Time Frame: 4 to 8 hours after breakfast ] [ Designated as safety issue: No ]
    Urinary norepinephrine excreted 4-8 hours after breakfast

  • Urinary Norepinephrine [ Time Frame: 8 to 12 hours after breakfast ] [ Designated as safety issue: No ]
    Urinary norepinephrine excreted 8-12 hours after breakfast

  • Supine Systolic Blood Pressure [ Time Frame: Supine-6 hours after breakfast on both study days. ] [ Designated as safety issue: No ]
    Supine systolic blood pressure 6 hours after breakfast

  • Supine Heart Rate [ Time Frame: 6 hours after breakfast ] [ Designated as safety issue: No ]
    Supine heart rate 6 hours after breakfast

  • Urinary Sodium [ Time Frame: 0-4 hours after breakfast ] [ Designated as safety issue: No ]
    Urinary sodium excreted 0-4 hours after breakfast.

  • Urinary Sodium [ Time Frame: 8-12 hours after breakfast ] [ Designated as safety issue: No ]
    urinary sodium 8-12 hours after breakfast


Enrollment: 14
Study Start Date: January 2007
Study Completion Date: December 2012
Primary Completion Date: September 2012 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Study Diet +/- fava beans
Participants underwent testing while on a methylxanthine-free diet providing 150 mEq sodium and 75 mEq potassium per day. The study involved a longitudinal design where the participants served as their own controls. Subjects consumed the standard fixed sodium diet on study day one. On study day two, participants ate 100 g of puréed fava beans and pods with study diet at breakfast (0800hr) and lunch (1200hr).
Dietary Supplement: Fava beans
Participants will receive 100g of fresh fava beans for breakfast and lunch on one study day and prior to this study day will be restricted to a fixed sodium low monoamine diet
Other: Fixed Sodium Diet

Detailed Description:

Fava beans are a broad bean, with potential clinical relevance in Parkinson's patients since they contain high levels of the dopamine precursor, dihydroxyphenylalanine (dopa).In addition to the central nervous system functions of dopamine that are compromised in Parkinson's disease, renal dopamine has vasodilatory and natriuretic activity. Elevated urinary dopamine, however, does not consistently correlate with increased urinary sodium excretion, and there are conflicting opinions over the conditions under which renal dopamine might regulate sodium balance.The goal of our study was to clarify the natriuretic effect of fava beans, obtained from a source that serves patients with Parkinson's disease. Catechol and sodium data were compared in healthy volunteers using a longitudinal design in which all participants consumed a fixed sodium study diet on day 1 and the fixed sodium diet plus fava beans on day 2. Blood was sampled at 1, 2, 4 and 6 hours after breakfast, and three consecutive 4-hr urine samples were collected.

Postural tachycardia syndrome (POTS) is the most common form of orthostatic intolerance, affecting an estimated 500,000 Americans, principally young women. POTS refers to an excessive increase in heart rate (>30 beats per minute) on standing in the absence of orthostatic hypotension. Previous findings by the Robertson/Garland research group suggest that mechanisms involved in orthostatic and absolute volume regulation contribute to POTS pathophysiology. A follow-up study might compare the influences of diet in patients with POTS and healthy volunteers.

  Eligibility

Ages Eligible for Study:   18 Years to 60 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Non-smoking
  • Free of medications with the potential to influence BP
  • Age between 18-60 years
  • Male and female subjects are eligible
  • Able and willing to provide informed consent

Exclusion Criteria:

  • Significant cardiovascular, pulmonary, hepatic, or hematological disease by history or screening results
  • Positive urine b-hcg pregnancy test
  • Evidence of cardiac structural disease (by clinical examination or prior echocardiogram)
  • Hypertension defined as a BP>145/95 (off medications) or need for antihypertensive medications
  • Evidence of significant conduction system delay (QRS duration >120 ms) on electrocardiogram
  • Inability to give, or withdraw, informed consent
  • Other factors which in the investigator's opinion would prevent the subject from completing the protocol Food allergies to favas or other dietary dopa sources selected
  • Parkinson's Disease
  • Diagnosis of Glucose-6-Phosphate Dehydrogenase (G6P) Deficiency or Individuals from the Mediterranean with family history of G6PD.
  • Prolonged QT interval on ECG> 480 13. Familial history of sudden cardiac death
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01064739

Locations
United States, Tennessee
Vanderbilt University Clinical Research Center
Nashville, Tennessee, United States, 37232-2195
Sponsors and Collaborators
Vanderbilt University
  More Information

No publications provided by Vanderbilt University

Additional publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Emily M. Garland, Research Associate Professor, Vanderbilt University
ClinicalTrials.gov Identifier: NCT01064739     History of Changes
Other Study ID Numbers: PN 1767
Study First Received: February 5, 2010
Results First Received: March 1, 2013
Last Updated: August 1, 2013
Health Authority: United States: Institutional Review Board

Keywords provided by Vanderbilt University:
Healthy Volunteers
Fava bean consumption
L-Dopa content in Fava Beans
Sodium
Potassium
Electrolyte Balance
Natriuresis

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

ClinicalTrials.gov processed this record on September 18, 2014