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Inorganic Nitrate Supplementation on Cerebrovascular Aging and Arterial Stiffness Study (INCA)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT03617302
Recruitment Status : Recruiting
First Posted : August 6, 2018
Last Update Posted : January 29, 2019
University of Wisconsin, Madison
Information provided by (Responsible Party):
Gary L. Pierce, University of Iowa

Brief Summary:
This study investigates the effect of dietary inorganic nitrate supplementation on 1) large elastic artery stiffness and hemodynamics and 2) cerebrovascular function in middle-aged and older adults. Participants will be randomized to consume either nitrate-containing or nitrate-depleted beetroot juice.

Condition or disease Intervention/treatment Phase
Aging Arterial Stiffness Endothelial Dysfunction Hypertension Cognitive Decline Drug: Experimental: Nitrate-containing Drug: Placebo: Nitrate-depleted Early Phase 1

Detailed Description:
Reduced nitric oxide bioavailability with aging contributes in part to increased large central artery stiffness and cerebrovascular dysfunction. Large central artery stiffness is a risk factor for cognitive decline mediated in part by the development of cerebrovascular dysfunction. This study will investigate the degree to which improving nitric oxide bioavailability using dietary inorganic nitrate supplementation improves cerebrovascular function through reductions in large central artery stiffness in middle-aged and older adults.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 18 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double (Participant, Investigator)
Primary Purpose: Treatment
Official Title: Effects of Inorganic Nitrate Supplementation on Cerebrovascular Aging and Arterial Stiffness Study
Actual Study Start Date : November 1, 2018
Estimated Primary Completion Date : October 2019
Estimated Study Completion Date : February 2020

Arm Intervention/treatment
Experimental: Beetroot juice
10-grams of nitrate-containing beetroot concentrate diluted in 120-180 milliliters of water.
Drug: Experimental: Nitrate-containing

Placebo Comparator: Placebo Beetroot juice
10 grams of nitrate-depleted beetroot concentrate balanced for anti-oxidant content diluted in 120-180 milliliters of water.
Drug: Placebo: Nitrate-depleted

Primary Outcome Measures :
  1. Acute change in carotid artery stiffness [ Time Frame: 2-hours ]
    Common carotid artery stiffness measured by ultrasonography and applanation tonometry.

  2. Acute change in cerebral blood flow [ Time Frame: 2-hours ]
    Large cerebral artery blood flow will be measured using 4-Dimensional (4D) phase contrast vastly undersampled isotropic projection imaging (pcVIPR) magnetic resonance imaging (MRI).

Secondary Outcome Measures :
  1. Internal carotid artery endothelium-dependent dilation [ Time Frame: 2-hours ]
    Endothelium-dependent dilation of the internal carotid artery in response to hypercapnia will be measured using ultrasonography.

Information from the National Library of Medicine

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Ages Eligible for Study:   50 Years to 79 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Age 50-79 years
  • Cognitively healthy, having mild cognitive impairment
  • Able to undergo cardiovascular testing procedures including fasting overnight and holding selected morning medication doses.
  • Ability to understand and willingness to sign a written informed consent document.
  • Ability to lie comfortably for up to 90 minutes
  • Women only: Post-menopausal

Exclusion Criteria:

  • Current or history of cardiovascular disease disease (heart attack, stroke, heart failure, cardiomyopathy or peripheral artery disease, heart angioplasty/stent or bypass surgery, valve replacement, carotid endarterectomy, heart transplant.
  • Medical history of stroke or other neurological disorder or systemic illness that could potentially affect cognition or brain function (outside of a diagnosis of Mild Cognitive impairment, Alzheimer's Disease) or could affect their safety or comfort while undergoing the imaging or cardiovascular studies.
  • Subjects with evidence of cardiovascular disease at baseline or during the exercise test (evidence of myocardial infarction, abnormal cardiac arrhythmia, myocardial ischemia, conduction delays, >1mm S-T segment depression or elevation; >3 beat ventricular tachycardia; atrial fibrillation) will be excluded from the study.
  • Wilson's disease, hemochromatosis
  • Individuals taking clonidine or other short-acting beta blocker
  • Resting blood pressure > 200/ 110 mmHg or systolic <90 mmHg
  • Medical history of chronic major psychiatric or current diagnosis of major psychiatric disease (other than dementia).
  • Systemic illness or neurological disorder potentially affecting cognition or cerebral blood flow other than mild cognitive impairment
  • Unable to provide informed consent due to cognitive impairment
  • Currently taking medications that may affect cerebral blood flow (e.g. papaverine, indomethacin, acetazolamide, etc) or efficacy of beetroot juice (proton pump inhibitors)
  • Current clinically abnormal thyroid function not adequately regulated by thyroid hormone supplementation or medication.
  • Allergic to beets
  • Current tobacco user or history of tobacco use within the past 3 months (cigarettes, cigars, chewing tobacco, hookah, electronic cigarettes) or living with someone who smokes/has smoked in the past 3 months.
  • Current diagnosis of insulin-dependent diabetes (Type I or insulin dependent Type II)
  • Current diagnosis of chronic obstructive lung disease, cystic fibrosis, emphysema, chronic bronchitis
  • History of renal failure, dialysis or kidney transplant
  • Current diagnosis or history of liver disease or HIV/AIDS, or cancer (other than non-melanoma skin cancers).
  • Current diagnosis or history of rheumatoid arthritis, systemic lupus erythematosus, Wegener's granulomatosis
  • Vulnerable populations (prisoners, etc) will not be eligible.
  • Unwillingness to wash out from a vitamin or dietary supplement regime prior to enrollment and maintain throughout the duration of the study.
  • Inability to comply with experimental instructions.
  • Uncontrolled intercurrent illness that would limit compliance with study requirements per investigator.
  • Inability to fast or hold morning medications doses until after testing is complete.
  • Hormone replacement use within the past 6 months
  • Currently enrolled in another study using an study medication, supplement, device or intervention.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT03617302

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Contact: Gary Pierce, PhD (319)335-9487
Contact: Lyndsey DuBose, MS (319)335-9488

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United States, Iowa
University of Iowa Recruiting
Iowa City, Iowa, United States, 52242
Contact: Gary Pierce, PhD   
Contact: Lyndsey DuBose, MS   
Sponsors and Collaborators
Gary L. Pierce
University of Wisconsin, Madison
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Principal Investigator: Gary Pierce, PhD University of Iowa

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Responsible Party: Gary L. Pierce, Principle Investigator, University of Iowa Identifier: NCT03617302     History of Changes
Other Study ID Numbers: 201805720
First Posted: August 6, 2018    Key Record Dates
Last Update Posted: January 29, 2019
Last Verified: January 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: Yes
Studies a U.S. FDA-regulated Device Product: No
Product Manufactured in and Exported from the U.S.: Yes
Keywords provided by Gary L. Pierce, University of Iowa:
Carotid artery stiffness
Cerebrovascular function
Cerebral blood flow
Beetroot juice
Dietary Inorganic Nitrate Supplementation
Cerebral Small Vessel Disease
Cerebrovascular Reserve
Neurovascular Coupling
Additional relevant MeSH terms:
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Cognitive Dysfunction
Cognition Disorders
Neurocognitive Disorders
Mental Disorders