Gary Pierce

Stiffening of your blood vessels, particularly the large vessels from your heart (called the aorta and carotids) you age contributes to the development of cardiovascular disease (CVD) such as heart attack and stroke. Nerve activity from your brain to your body also increases with advancing age but it is unknown if this nerve activity contributes directly to the stiffening on your blood vessels in older adults in addition to high blood pressure. Therefore, successful completion of the proposed aims will have a significant clinical impact by identifying if nerve activity from your brain could be a novel target for therapies that would lower stiffness of the aorta and carotid arteries in older adults.

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.

The purpose of the study is to test the effects of blocking sympathetic nerve activity with a drug called clonidine on blood vessel function and muscle nerve activity in adults who are obese and have high blood pressure.

The cohort of subjects will consist of 69 healthy young men and women age 18-79 years who are obese, defined as a body mass index \> or = to 30 kg/m2, who have untreated systolic hypertension (systolic blood pressure \> or = to 130 - \<180 mmHg- average of at least 3 measurements 2 min apart after 10 min seated resting position). These 69 subjects will then be randomized to 3 treatment arms: clonidine (0.1 mg/day), hydrochlorothiazide (25 mg/day) or placebo for 4 weeks in years 1 and 2. All tablets will be encapsulated by to look identical. Subjects will randomly (1:1:1) receive one of the following combinations in a double-blind, placebo-controlled design:

1. Oral clonidine (0.1 mg twice/day)
2. Oral hydrochlorothiazide (12.5 mg twice/day)
3. Oral placebo

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