Renal Salt Handling in Postural Tachycardia Syndrome Following Dietary Dopa Administration

NCT01064739 | Completed Early Phase 1 Results

• 1 other identifier: PN 1767
• Study Type: interventional
• Target: 14
• Locations: 1 country
• Sites: 1

Brief Summary

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

Conditions

Healthy Participants

Keywords

Healthy Volunteers; Fava bean consumption; L-Dopa content in Fava Beans; Sodium; Potassium; Electrolyte Balance; Natriuresis

Outcome Measures

Primary Outcomes (3)

• Plasma Dopa 1 hr After Breakfast

  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 samples collected 1 hour after breakfast on both study days.

• Urinary Dopa

  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.

  4-8 hours after breakfast

• Urinary Sodium

  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.

  4 to 8 hours after breakfast

Secondary Outcomes (23)

• Plasma Dopa 2 Hrs After Breakfast

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

• Plasma Dopa 4 Hrs After Breakfast

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

• Plasma Dopa 6 Hrs After Breakfast

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

• Plasma Norepinephrine

  1 hour after breakfast on both study days.

• Plasma Norepinephrine

  2 hours after breakfast on both study days.

Study Arms (1)

Study Diet +/- fava beans

EXPERIMENTAL

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; Other: Fixed Sodium Diet

Interventions

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

Study Diet +/- fava beans

Fixed Sodium Diet OTHER

Fixed sodium low monoamine diet

Study Diet +/- fava beans

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Vanderbilt University: lead

Study Sites (1)

Vanderbilt University Clinical Research Center

Nashville, Tennessee, 37232-2195, United States

Location

Related Publications (1)

• Garland EM, Cesar TS, Lonce S, Ferguson MC, Robertson D. An increase in renal dopamine does not stimulate natriuresis after fava bean ingestion. Am J Clin Nutr. 2013 May;97(5):1144-50. doi: 10.3945/ajcn.112.048470. Epub 2013 Apr 3.

  PMID: 23553159 DERIVED

Results Point of Contact

• Title: Dr. Emily Garland
• Organization: Vanderbilt University

emily.garland@vanderbilt.edu

615 936 1748

Study Officials

• Emily M Garland, PhD

  Vanderbilt University Medical Center

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: Yes

Study Design

• Study Type: interventional
• Phase: early phase 1
• Allocation: NA
• Masking: NONE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Research Associate Professor

Study Record Dates

• First Submitted: February 5, 2010
• First Posted: February 8, 2010
• Study Start: January 1, 2007
• Primary Completion: September 1, 2012
• Study Completion: December 1, 2012
• Last Updated: May 26, 2016
• Results First Posted: July 31, 2013

Record last verified: 2013-08

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)