The Natriuretic Peptide System in African-Americans.

Healthy Clinical Trial

Official title:

The Natriuretic Peptide System in African-Americans.

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02730780
• Other study ID #: 151943
• Status: Completed
• Phase: N/A
• Start date: July 22, 2016
• Est. completion date: May 20, 2021

Study information

• Verified date: November 2022
• Source: Vanderbilt University Medical Center
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

This study aims to assess the natriuretic peptide response to dietary salt loading in African-American individuals compared with white individuals.

Description:

High blood pressure, or hypertension, is a major cause of heart disease, heart failure, and stroke. Natriuretic peptides are cardiac derived hormones that may protect against hypertension. The classical actions of the natriuretic peptides include natriuresis, vasodilation, and inhibition of the renin-angiotensin-aldosterone system (RAAS), which support a key role for these hormones in blood pressure regulation.

Race based differences exist in the risk and severity of hypertension and cardiovascular disease, with African-American individuals typically being at greater risk compared with white individuals. Nearly half of African-American adults have hypertension, compared with one-third of whites. Additionally, salt-sensitivity denotes the impaired ability to handle a salt load with resulting increases in blood pressure. It is estimated that 75% of hypertensive African-Americans exhibit salt-sensitivity, compared with 35% of hypertensive whites. Why this predilection towards salt-sensitivity exists, particularly among African-American individuals, is not well understood. Thus, establishing the origins of salt retention in African Americans has biologic, preventative, and therapeutic importance, and may provide insight regarding racial differences in cardiovascular risk.

The natriuretic peptide system is the principal counter-regulatory mechanism to salt retention. However, little is known regarding racial differences in the natriuretic peptide system. Recently, it was discovered that African-Americans have lower natriuretic peptide levels compared with whites, raising the possibility that African-Americans individuals can have a relative "natriuretic peptide deficiency" with reduced natriuretic peptide responses to salt loading. However, the prior studies were based on epidemiologic data with individuals on random salt backgrounds. This highlights the need for more detailed physiologic studies, under controlled salt conditions and with standardized assessment of the natriuretic peptide and RAAS and tissue sodium stores.

The aim of this study is to assess the natriuretic peptide response to dietary salt loading in African-American individuals compared with white individuals. This study will test the primary hypothesis that compared with whites, African-American individuals have blunted natriuretic peptide responses to dietary salt loading.

Secondary hypotheses include:

1. Compared with white individuals, African-American individuals have higher baseline tissue sodium content, and

2. Compared with white individuals, African-American individuals have impaired "target organ" responses to salt loading, as manifested by higher blood pressure and increased frequency of salt-sensitive hypertension, decreased urinary sodium excretion, less suppression of plasma renin and serum aldosterone, and lack of increase in left ventricular early diastolic relaxation velocities.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 60
• Est. completion date: May 20, 2021
• Est. primary completion date: May 20, 2021
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 55 Years

Eligibility

Inclusion Criteria:

• age between 18 and 55 years

• BMI between 18 and <25 kg/m2

• normotensive or pre-hypertensive

• willing to adhere to study diets

Exclusion Criteria:

• prevalent cardiovascular disease or use of medications for cardiovascular disease

• Current or prior history of hypertension or use of blood pressure lowering medications

• Current or prior history of diabetes mellitus or use of anti-diabetic medications

• Prevalent renal disease (eGFR < 60 ml/min/1.73m2), abnormal serum sodium or potassium

• Current or prior smoker

• Current pregnancy

• Current steroid use

• Contraindications to MRI

Related Conditions & MeSH terms

• Healthy
• Prehypertension

Intervention

Dietary Supplement:
• Low-Salt Diet
The low-salt diet (7 days) will consist of meals, snacks, and sodium free water provided by the study staff.
• High-Salt Diet
The high-salt diet (7 days) consists of each subject's usual diet, supplemented each day with 2 bouillon broth packets, which will be provided to the subject by the study staff.

Locations

Country	Name	City	State
United States	Vanderbilt Univeristy	Nashville	Tennessee

Sponsors (1)

Lead Sponsor	Collaborator
Vanderbilt University

Country where clinical trial is conducted

United States, 

References & Publications (2)

Gupta DK, Claggett B, Wells Q, Cheng S, Li M, Maruthur N, Selvin E, Coresh J, Konety S, Butler KR, Mosley T, Boerwinkle E, Hoogeveen R, Ballantyne CM, Solomon SD. Racial differences in circulating natriuretic peptide levels: the atherosclerosis risk in communities study. J Am Heart Assoc. 2015 May 21;4(5). pii: e001831. doi: 10.1161/JAHA.115.001831. — View Citation

Gupta DK, de Lemos JA, Ayers CR, Berry JD, Wang TJ. Racial Differences in Natriuretic Peptide Levels: The Dallas Heart Study. JACC Heart Fail. 2015 Jul;3(7):513-519. doi: 10.1016/j.jchf.2015.02.008. Epub 2015 Jun 10. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	The difference in circulating NT-proANP levels in response to low and high dietary salt.		4 years
Secondary	Tissue sodium content	Measured by sodium MRI	4 years
Secondary	Blood pressure		4 years
Secondary	Salt-sensitive hypertension	Measured by change in mean arterial pressure	4 years
Secondary	Urinary sodium excretion	Measured from 24 hour urine collection	4 years
Secondary	Myocardial early relaxation velocities	Measured from Echocardiography as tissue Doppler e'	4 years
Secondary	Plasma renin	Physiological parameter	4 years
Secondary	Serum aldosterone	Physiological parameter	4 years