Renal Salt Handling in Postural Tachycardia Syndrome Following Dietary Dopa Administration
Palabras clave
Abstracto
Descripción
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.
fechas
| Verificado por última vez: | 07/31/2013 |
| Primero enviado: | 02/04/2010 |
| Inscripción estimada enviada: | 02/04/2010 |
| Publicado por primera vez: | 02/07/2010 |
| Última actualización enviada: | 04/25/2016 |
| Última actualización publicada: | 05/25/2016 |
| Fecha de los primeros resultados enviados: | 02/28/2013 |
| Fecha de los primeros resultados de CC enviados: | 06/17/2013 |
| Fecha de los primeros resultados publicados: | 07/30/2013 |
| Fecha de inicio real del estudio: | 12/31/2006 |
| Fecha estimada de finalización primaria: | 08/31/2012 |
| Fecha estimada de finalización del estudio: | 11/30/2012 |
Condición o enfermedad
Intervención / tratamiento
Dietary Supplement: Study Diet +/- fava beans
Other: Study Diet +/- fava beans
Fase
Grupos de brazos
| Brazo | Intervención / tratamiento |
|---|---|
| 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: Study Diet +/- 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 |
Criterio de elegibilidad
| Edades elegibles para estudiar | 18 Years A 18 Years |
| Sexos elegibles para estudiar | All |
| Acepta voluntarios saludables | si |
| Criterios | 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 |
Salir
Medidas de resultado primarias
1. Plasma Dopa 1 hr After Breakfast [Plasma samples collected 1 hour after breakfast on both study days.]
2. Urinary Dopa [4-8 hours after breakfast]
3. Urinary Sodium [4 to 8 hours after breakfast]
Medidas de resultado secundarias
1. Plasma Dopa 2 Hrs After Breakfast [Plasma samples collected 2 hours after breakfast on both study days.]
2. Plasma Dopa 4 Hrs After Breakfast [Plasma samples collected 4 hours after breakfast on both study days.]
3. Plasma Dopa 6 Hrs After Breakfast [Plasma samples collected 6 hours after breakfast on both study days.]
4. Plasma Norepinephrine [1 hour after breakfast on both study days.]
5. Plasma Norepinephrine [2 hours after breakfast on both study days.]
6. Plasma Norepinephrine [4 hours after breakfast on both study days.]
7. Plasma Norepinephrine [6 hours after breakfast on both study days.]
8. Plasma Dopamine [1 hour after breakfast]
9. Plasma Dopamine [2 hours after breakfast on both study days.]
10. Plasma Dopamine [4 hours after breakfast on both study days.]
11. Plasma Dopamine [Plasma samplesPlasma dopamine 6 hours after breakfast on both study days.]
12. Urinary Dopa [0-4 hours after breakfast]
13. Urinary Dopa [8-12 hours after breakfast]
14. Urinary Dopamine [0 to 4 hours after breakfast]
15. Urinary Dopamine [4 to 8 hours after breakfast]
16. Urinary Dopamine [8 to 12 hours after breakfast]
17. Urinary Norepinephrine [0 to 4 hours after breakfast]
18. Urinary Norepinephrine [4 to 8 hours after breakfast]
19. Urinary Norepinephrine [8 to 12 hours after breakfast]
20. Supine Systolic Blood Pressure [Supine-6 hours after breakfast on both study days.]
21. Supine Heart Rate [6 hours after breakfast]
22. Urinary Sodium [0-4 hours after breakfast]
23. Urinary Sodium [8-12 hours after breakfast]
