The Role of Aldosterone on Augmented Exercise Pressor Reflex in Hypertension

NCT ID: NCT01996449

Last Updated: 2022-03-18

Study Results

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Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

PHASE2

Total Enrollment

14 participants

Study Classification

INTERVENTIONAL

Study Start Date

2013-07-31

Study Completion Date

2021-04-30

Brief Summary

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Hypertensive patients often show an exaggerated rise in blood pressure during exercise through overactivity of the exercise pressor reflex. An increasing body of evidence suggests a role for aldosterone in augmenting the exercise pressor reflex in hypertensive humans. We hypothesize that this effect of aldosterone is mediated by its direct action on the central nervous system and that administration of mineralocorticoid receptor antagonists constitute an effective treatment for EPR overactivity in hypertension, independent of reductions in resting BP.

Detailed Description

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Hypertensive patients are known to display exaggerated rise in blood pressure (BP) during exercise but the underlying mechanisms are poorly understood.

Traditionally, muscle afferents were dichotomized as metaboreceptors, which are activated slowly and only during intense or ischemic muscle contraction, or mechanoreceptors, which respond quickly to even mild deformation of their receptive fields. The increase in sympathetic nerve activity and BP caused by activation of these receptors, known as exercise pressor reflex, is normally buffered by activation arterial baroreceptors, which are reset to operate at higher BP range but at the same level of sensitivity. Mechanisms responsible for overactive exercise pressor reflex in hypertension remain unknown, but an increasing body of evidence suggested a role for aldosterone in regulating resting central sympathetic outflow in both hypertensive rats and humans.

Experiments will be performed on 3 groups of subjects 1) stage I (140-159/90-99 mmHg) subjects with essential hypertension, 2) stage I hypertensive subjects with Primary Aldosteronism (PA), and 3) normotensive controls. All participants will attend a baseline study visit, which will include a physical examination, a medical history review, vital sign measurements, and blood and urine collection. Small electrodes will be used to measure muscle nerve activity while the subjects perform a series of exercises that include passive arm cycling, active arm cycling, rhythmic hand grip, sustained hand grip and cold pressor test. Muscle blood flow will be measured before and after hand grip exercises.

A subgroup of subjects with essential hypertension and PA will be assigned to receive Eplerenone or Amlodipine on a randomized, double-blinded design. Participants will attend two weeks visits over a period of 16 weeks. Study visits include measurement of vital signs and blood samples collection. After completing 8 weeks on each medication, muscle nerve activity will be measured while performing the same exercises described in the baseline study visit.

Conditions

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Hypertension

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

SINGLE

Participants

Study Groups

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Initial treatment with Amlodipine

The subject will be started on Amlodipine 2.5-10 mg daily, which he or she will continue for a period of 12 weeks. Following the 12-week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued. The subject will be started on Eplerenone 50 - 200 mg daily, which he or she will continue for a period of 8 weeks. Following the 8 week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued.

Group Type ACTIVE_COMPARATOR

Eplerenone

Intervention Type DRUG

The subject will be started on Eplerenone (Inspra) 50-200mg daily, which he or she will continue for a period of 8 weeks. Following the 8-week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued

Amlodipine

Intervention Type DRUG

The subject will be started on Amlodipine (Norvasc) 2.5 -10mg daily, which he or she will continue for a period of 8 weeks. Following the 8-week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued.

Microneurography

Intervention Type PROCEDURE

Investigators will measure sympathetic nerve activity from the peroneal nerve by inserting a tiny needle directly into the nerve in the leg. Investigators will localize the nerve by electrical stimulation over the skin using a blunt probe. With this stimulation, subject will notice either involuntary twitching or a tingling sensation, which may be annoying but not painful. Investigators will then introduce a tiny, sterile wire needle (an electrode) through the skin at the same location. When the tip of the needle enters the nerve, subjects may again notice involuntary muscle twitches or tingling in the leg. Investigators will then turn the electrical stimulator off and make minor adjustments in the position of the needle until investigators begin to record the nerve signals. The recording needle will remain in position throughout the study.

Rhythmic handgrip exercise

Intervention Type PROCEDURE

Subjects will perform a rhythmic handgrip exercise at 30% or 45% of maximal voluntary contraction for 3 minutes. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline and following this handgrip exercise

Sustained hand grip

Intervention Type PROCEDURE

Subjects will perform a sustained handgrip exercise at 30% of maximal voluntary contraction for 3 minutes. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline and following this handgrip exercise.

Forearm blood flow

Intervention Type PROCEDURE

Using high-resolution ultrasound, investigators will measure skeletal muscle blood flow in the forearm at rest, following sustained handgrip exercise

Arm cycling exercise

Intervention Type PROCEDURE

Subjects will perform a cycling arm exercise with a stationary cycling device. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline and following this exercise.

Cold Pressor test

Intervention Type PROCEDURE

Subjects will place hand in cold water with ice for 3 minutes. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline, during and 2 minutes after the test.

Initial treatment with Eplerenone

The subject will be started on Eplerenone 50 - 200 mg daily, which he or she will continue for a period of 12 weeks. Following the 12-week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued. The subject will be started on Amlodipine 2.5-10 mg daily, which he or she will continue for a period of 8 weeks. Following the 8 week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued.

Group Type ACTIVE_COMPARATOR

Eplerenone

Intervention Type DRUG

The subject will be started on Eplerenone (Inspra) 50-200mg daily, which he or she will continue for a period of 8 weeks. Following the 8-week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued

Amlodipine

Intervention Type DRUG

The subject will be started on Amlodipine (Norvasc) 2.5 -10mg daily, which he or she will continue for a period of 8 weeks. Following the 8-week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued.

Microneurography

Intervention Type PROCEDURE

Investigators will measure sympathetic nerve activity from the peroneal nerve by inserting a tiny needle directly into the nerve in the leg. Investigators will localize the nerve by electrical stimulation over the skin using a blunt probe. With this stimulation, subject will notice either involuntary twitching or a tingling sensation, which may be annoying but not painful. Investigators will then introduce a tiny, sterile wire needle (an electrode) through the skin at the same location. When the tip of the needle enters the nerve, subjects may again notice involuntary muscle twitches or tingling in the leg. Investigators will then turn the electrical stimulator off and make minor adjustments in the position of the needle until investigators begin to record the nerve signals. The recording needle will remain in position throughout the study.

Rhythmic handgrip exercise

Intervention Type PROCEDURE

Subjects will perform a rhythmic handgrip exercise at 30% or 45% of maximal voluntary contraction for 3 minutes. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline and following this handgrip exercise

Sustained hand grip

Intervention Type PROCEDURE

Subjects will perform a sustained handgrip exercise at 30% of maximal voluntary contraction for 3 minutes. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline and following this handgrip exercise.

Forearm blood flow

Intervention Type PROCEDURE

Using high-resolution ultrasound, investigators will measure skeletal muscle blood flow in the forearm at rest, following sustained handgrip exercise

Arm cycling exercise

Intervention Type PROCEDURE

Subjects will perform a cycling arm exercise with a stationary cycling device. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline and following this exercise.

Cold Pressor test

Intervention Type PROCEDURE

Subjects will place hand in cold water with ice for 3 minutes. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline, during and 2 minutes after the test.

Interventions

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Eplerenone

The subject will be started on Eplerenone (Inspra) 50-200mg daily, which he or she will continue for a period of 8 weeks. Following the 8-week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued

Intervention Type DRUG

Amlodipine

The subject will be started on Amlodipine (Norvasc) 2.5 -10mg daily, which he or she will continue for a period of 8 weeks. Following the 8-week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued.

Intervention Type DRUG

Microneurography

Investigators will measure sympathetic nerve activity from the peroneal nerve by inserting a tiny needle directly into the nerve in the leg. Investigators will localize the nerve by electrical stimulation over the skin using a blunt probe. With this stimulation, subject will notice either involuntary twitching or a tingling sensation, which may be annoying but not painful. Investigators will then introduce a tiny, sterile wire needle (an electrode) through the skin at the same location. When the tip of the needle enters the nerve, subjects may again notice involuntary muscle twitches or tingling in the leg. Investigators will then turn the electrical stimulator off and make minor adjustments in the position of the needle until investigators begin to record the nerve signals. The recording needle will remain in position throughout the study.

Intervention Type PROCEDURE

Rhythmic handgrip exercise

Subjects will perform a rhythmic handgrip exercise at 30% or 45% of maximal voluntary contraction for 3 minutes. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline and following this handgrip exercise

Intervention Type PROCEDURE

Sustained hand grip

Subjects will perform a sustained handgrip exercise at 30% of maximal voluntary contraction for 3 minutes. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline and following this handgrip exercise.

Intervention Type PROCEDURE

Forearm blood flow

Using high-resolution ultrasound, investigators will measure skeletal muscle blood flow in the forearm at rest, following sustained handgrip exercise

Intervention Type PROCEDURE

Arm cycling exercise

Subjects will perform a cycling arm exercise with a stationary cycling device. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline and following this exercise.

Intervention Type PROCEDURE

Cold Pressor test

Subjects will place hand in cold water with ice for 3 minutes. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline, during and 2 minutes after the test.

Intervention Type PROCEDURE

Other Intervention Names

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Inspra Norvasc Assessment of sympathetic nerve activity (SNA)

Eligibility Criteria

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Inclusion Criteria

* Experiments will be performed on 3 groups of nondiabetic human subjects:
* 1\) stage I (140-159/90-99 mmHg) subjects with essential hypertension.
* 2\) stage I hypertensive subjects with primary aldosteronism
* 3\) normotensive controls.

Exclusion Criteria

* 1\) Any evidence of cardiopulmonary disease, left ventricular hypertrophy or systolic dysfunction by echocardiography.
* 2\) Blood pressure averaging ≥160/100 mmHg
* 3\) Estimated glomerular filtration rate (eGFR) \< 90 mL/min/1.73m2
* 4\) Diabetes mellitus or other systemic illness
* 5\) Pregnancy
* 6\) Hypersensitivity to nitroprusside, phenylephrine, amlodipine or eplerenone
* 7\) Any history of substance abuse or current cigarette use
* 8\) Any history of psychiatric illness
* 9\) History of malignancy
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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University of Texas Southwestern Medical Center

OTHER

Sponsor Role lead

Responsible Party

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Wanpen Vongpatanasin

Professor

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Wanpen Vongpatanasin, MD

Role: PRINCIPAL_INVESTIGATOR

UT Southwestern Medical Center

Locations

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UT Southwestern Medical Center

Dallas, Texas, United States

Site Status

Countries

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United States

References

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Fagard R, Staessen J, Amery A. Maximal aerobic power in essential hypertension. J Hypertens. 1988 Nov;6(11):859-65. doi: 10.1097/00004872-198811000-00003.

Reference Type BACKGROUND
PMID: 3235835 (View on PubMed)

Olsen MH, Wachtell K, Hermann KL, Bella JN, Andersen UB, Dige-Petersen H, Rokkedal J, Ibsen H. Maximal exercise capacity is related to cardiovascular structure in patients with longstanding hypertension. A LIFE substudy. Losartan Intervention For Endpoint-Reduction in Hypertension. Am J Hypertens. 2001 Dec;14(12):1205-10. doi: 10.1016/s0895-7061(01)02223-3.

Reference Type BACKGROUND
PMID: 11775128 (View on PubMed)

Filipovsky J, Ducimetiere P, Safar ME. Prognostic significance of exercise blood pressure and heart rate in middle-aged men. Hypertension. 1992 Sep;20(3):333-9. doi: 10.1161/01.hyp.20.3.333.

Reference Type BACKGROUND
PMID: 1387630 (View on PubMed)

Cleroux J, Beaulieu M, Kouame N, Lacourciere Y. Comparative effects of quinapril, atenolol, and verapamil on blood pressure and forearm hemodynamics during handgrip exercise. Am J Hypertens. 1994 Jun;7(6):566-70. doi: 10.1093/ajh/7.6.566.

Reference Type BACKGROUND
PMID: 7917158 (View on PubMed)

Vongpatanasin W, Wang Z, Arbique D, Arbique G, Adams-Huet B, Mitchell JH, Victor RG, Thomas GD. Functional sympatholysis is impaired in hypertensive humans. J Physiol. 2011 Mar 1;589(Pt 5):1209-20. doi: 10.1113/jphysiol.2010.203026. Epub 2011 Jan 4.

Reference Type BACKGROUND
PMID: 21224235 (View on PubMed)

Grassi G, Spaziani D, Seravalle G, Bertinieri G, Dell'Oro R, Cuspidi C, Mancia G. Effects of amlodipine on sympathetic nerve traffic and baroreflex control of circulation in heart failure. Hypertension. 1999 Feb;33(2):671-5. doi: 10.1161/01.hyp.33.2.671.

Reference Type BACKGROUND
PMID: 10024325 (View on PubMed)

Funder JW, Carey RM, Fardella C, Gomez-Sanchez CE, Mantero F, Stowasser M, Young WF Jr, Montori VM; Endocrine Society. Case detection, diagnosis, and treatment of patients with primary aldosteronism: an endocrine society clinical practice guideline. J Clin Endocrinol Metab. 2008 Sep;93(9):3266-81. doi: 10.1210/jc.2008-0104. Epub 2008 Jun 13.

Reference Type BACKGROUND
PMID: 18552288 (View on PubMed)

Provided Documents

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Document Type: Study Protocol and Statistical Analysis Plan

View Document

Document Type: Informed Consent Form

View Document

Other Identifiers

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R01HL113738

Identifier Type: NIH

Identifier Source: org_study_id

View Link

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