Endogenous Renin-Angiotensin-Aldosterone System and Glucose Metabolism

Aim 1.Test the hypothesis that activation of the endogenous renin-angiotensin-aldosterone system impairs glycemic control via effects on insulin sensitivity and insulin secretion.

Aim 2. Test the hypothesis that activation of the endogenous renin-angiotensin-aldosterone system impairs insulin secretion and insulin sensitivity via an mineralocorticoid-receptor dependent mechanism.

Study Overview

• Status: Completed
• Conditions: Metabolic Syndrome
• Intervention / Treatment: Other: Low Salt diet plus Placebo tablet; Other: Low Sodium diet plus Salt tablet; Drug: Epleronone; Drug: Amlodipine

Detailed Description

In aim 1 subjects are randomized to cross over between an 8 day high salt and 8 day low salt diet and assessments are made.

In aim 2, subjects are randomized to a 2x2 cross over study with an 8 day low salt diet and either eplerenone 50mg or amlodipine 5mg.

• Study Type: Interventional
• Enrollment (Actual): 44
• Phase: Phase 4

Contacts and Locations

Study Locations

• United States
  • Tennessee
    • Nashville, Tennessee, United States, 37232-6602
      • Vanderbilt University Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

1. Ambulatory subjects, 18 to 70 years of age, inclusive

2. For female subjects, the following conditions must be met:

   1. postmenopausal status for at least 1 year, or
   2. status-post surgical sterilization, or
   3. if of childbearing potential, utilization of adequate birth control and willingness to undergo urine beta-hcg testing prior to drug treatment and on every study day.

3. Metabolic Syndrome as defined by the presence of > 3 of the following:

   1. Systolic Blood Pressure > 130 mm Hg OR Diastolic Blood Pressure > 85 mm Hg.
   2. Glucose Intolerance (Fasting Plasma Glucose ≥ 100 mg/dL)
   3. Increased triglyceride level > 150mg/dL (1.7mmol/L)
   4. Decreased levels of HDL cholesterol (For males, less than 40 mg/dL; For females, less than 50 mg/dL)
   5. Waist circumference (For males, greater than 40 inches; For females, greater than 35 inches)

Exclusion Criteria:

1. type 1 Diabetes
2. Type II Diabetes
3. Impaired renal function
4. Prior allergies to medications used in the study protocol
5. Screening plasma potassium >5.5 mmol/L or sodium <135 mmol/L
6. Cardiovascular disease
7. Use of hormone replacement therapy
8. Breast-feeding
9. Treatment with anticoagulants
10. History of serious neurologic disease
11. History or presence of immunological or hematological disorders
12. Diagnosis of asthma requiring use of inhaled beta agonist
13. Clinically significant gastrointestinal impairment
14. Impaired hepatic function
15. Hematocrit <35%
16. Any underlying or acute disease requiring regular medication which could possibly pose a threat to the subject or make implementation of the protocol or interpretation of the study results difficult, such as arthritis treated with non-steroidal antiinflammatory drugs
17. Treatment with chronic systemic glucocorticoid therapy
18. Treatment with lithium salts
19. History of alcohol or drug abuse
20. Treatment with any investigational drug in the 1 month preceding
21. Mental conditions rendering the subject unable to understand the nature, scope and possible consequences of the study
22. Inability to comply with the protocol, e.g., uncooperative attitude, inability to return for follow-up visits, and unlikelihood of completing the study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Aim1-Low Sodium then High Sodium; Subjects will be provided with a low sodium diet from the Vanderbilt Clinical Research Center that will be controlled for salt content. Participants will be given low sodium diet (50mEq/d) and Placebo tablets for 8 days and assessments will be made, washout and then cross over to a low sodium diet (50mEq/d) plus Salt tables (150mEq) for 8days and assessments will be made.	Other: Low Salt diet plus Placebo tablet; Other: Low Sodium diet plus Salt tablet
Active Comparator: Aim 1-high salt diet then low salt diet; Subjects will be provided with a diet from the Vanderbilt Clinical Research Center that will be controlled for salt content. Participants will be given low sodium diet (50mEq/d) and Salt tables (150mEq) for 8 days and assessments will be made, washout and then cross over to a low sodium diet (50mEq/d) plus Placebo tablets for 8days and assessments will be made.	Other: Low Salt diet plus Placebo tablet; Other: Low Sodium diet plus Salt tablet
Active Comparator: Aim2- low salt diet and epleronone then amlodipine; Subjects on a low salt diet will receive Epleronone 50mg for 8 days and assessments will be made, then cross over to a low salt diet with Amlodipine 5mg for 8days and assessments will be made.	Other: Low Salt diet plus Placebo tablet; Drug: Epleronone; 50mg daily; Other Names: Inspra; Drug: Amlodipine; 5mg daily; Other Names: Norvasc
Active Comparator: aim2- low salt diet and amlodipine then epleronone; Subjects on a low salt diet will receive Amlodipine 5mg for 8 days and assessments will be made, then cross over to a low salt diet with Epleronone 50mg for 8days and assessments will be made.	Other: Low Salt diet plus Placebo tablet; Drug: Epleronone; 50mg daily; Other Names: Inspra; Drug: Amlodipine; 5mg daily; Other Names: Norvasc

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Insulin Secretion	Hyperglycemic clamp- acute insulin response (AIR) during time 0-10 minutes	After 8 days of diet or drug
Insulin Sensitivity	Hyperinsulinemic clamp- glucose infusion rate during insulin administration	after 8 days of diet or medication

Collaborators and Investigators

• Sponsor: Vanderbilt University Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): October 1, 2013
• Primary Completion (Actual): December 1, 2019
• Study Completion (Actual): December 1, 2019

Study Registration Dates

• First Submitted: January 9, 2014
• First Submitted That Met QC Criteria: January 10, 2014
• First Posted (Estimate): January 13, 2014

Study Record Updates

• Last Update Posted (Actual): January 20, 2021
• Last Update Submitted That Met QC Criteria: December 30, 2020
• Last Verified: December 1, 2020

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Insulin Resistance; Hyperinsulinism; Metabolic Syndrome; Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Antihypertensive Agents; Vasodilator Agents; Membrane Transport Modulators; Calcium-Regulating Hormones and Agents; Calcium Channel Blockers; Amlodipine
• Other Study ID Numbers: 131139

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• product manufactured in and exported from the U.S.: No