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Completed

NCT Number: NCT01064739

Renal Salt Handling in Postural Tachycardia Syndrome Following Dietary Dopa Administration

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.

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Key information

Conditions

Healthy Participants

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Early Phase 1

Primary location

Vanderbilt University Clinical Research Center

Nashville, Tennessee, 37232-2195, United States

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Fava beans

Dietary Supplement

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

Fixed Sodium Diet

Other

Fixed sodium low monoamine diet

Primary outcomes

  1. Plasma Dopa 1 hr After Breakfast

    Time frame: Plasma samples collected 1 hour after breakfast on both study days.

    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.

  2. Urinary Dopa

    Time frame: 4-8 hours after breakfast

    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.

  3. Urinary Sodium

    Time frame: 4 to 8 hours after breakfast

    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 outcomes

  1. Plasma Dopa 2 Hrs After Breakfast

    Time frame: Plasma samples collected 2 hours after breakfast on both study days.

    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.

  2. Plasma Dopa 4 Hrs After Breakfast

    Time frame: Plasma samples collected 4 hours after breakfast on both study days.

    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.

  3. Plasma Dopa 6 Hrs After Breakfast

    Time frame: Plasma samples collected 6 hours after breakfast on both study days.

    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.

  4. Plasma Norepinephrine

    Time frame: 1 hour after breakfast on both study days.

    Plasma norepinephrine 1 hour after breakfast

  5. Plasma Norepinephrine

    Time frame: 2 hours after breakfast on both study days.

    Plasma norepinephrine 2 hours after breakfast

  6. Plasma Norepinephrine

    Time frame: 4 hours after breakfast on both study days.

    Plasma norepinephrine 4 hours after breakfast

  7. Plasma Norepinephrine

    Time frame: 6 hours after breakfast on both study days.

    Plasma norepinephrine 6 hours after breakfast

  8. Plasma Dopamine

    Time frame: 1 hour after breakfast

    Plasma dopamine 1 hour after breakfast

  9. Plasma Dopamine

    Time frame: 2 hours after breakfast on both study days.

    Plasma dopamine 2 hours after breakfast

  10. Plasma Dopamine

    Time frame: 4 hours after breakfast on both study days.

    Plasma dopamine 4 hours after breakfast

  11. Plasma Dopamine

    Time frame: Plasma samplesPlasma dopamine 6 hours after breakfast on both study days.

    Plasma dopamine 6 hours after breakfast

  12. Urinary Dopa

    Time frame: 0-4 hours after breakfast

    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.

  13. Urinary Dopa

    Time frame: 8-12 hours after breakfast

    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.

  14. Urinary Dopamine

    Time frame: 0 to 4 hours after breakfast

    Urinary dopamine excreted 0 to 4 hours after breakfast

  15. Urinary Dopamine

    Time frame: 4 to 8 hours after breakfast

    Urinary dopamine excreted 4 to 8 hours after breakfast

  16. Urinary Dopamine

    Time frame: 8 to 12 hours after breakfast

    Urinary dopamine excreted 8 to 12 hours after breakfast

  17. Urinary Norepinephrine

    Time frame: 0 to 4 hours after breakfast

    Urinary norepinephrine excreted 0-4 hours after breakfast

  18. Urinary Norepinephrine

    Time frame: 4 to 8 hours after breakfast

    Urinary norepinephrine excreted 4-8 hours after breakfast

  19. Urinary Norepinephrine

    Time frame: 8 to 12 hours after breakfast

    Urinary norepinephrine excreted 8-12 hours after breakfast

  20. Supine Systolic Blood Pressure

    Time frame: Supine-6 hours after breakfast on both study days.

    Supine systolic blood pressure 6 hours after breakfast

  21. Supine Heart Rate

    Time frame: 6 hours after breakfast

    Supine heart rate 6 hours after breakfast

  22. Urinary Sodium

    Time frame: 0-4 hours after breakfast

    Urinary sodium excreted 0-4 hours after breakfast.

  23. Urinary Sodium

    Time frame: 8-12 hours after breakfast

    urinary sodium 8-12 hours after breakfast

Sponsors and collaborators

Lead sponsor

Vanderbilt University

Other

Registry information

Important dates

Study start
2007
Primary completion
2012
Study completion
2012
First posted
Feb 8, 2010
Registry last updated
May 26, 2016

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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