Aging, Endothelial Dysfunction, Hypertension, Men
Conditions
Keywords
Cardiovascular Disease, Blueberries, Hypertension, Vascular Dysfunction, Atherosclerosis, Aging
Brief summary
Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide. Aging is the primary risk factor for CVD, in large part due to adverse modifications to the arteries. These modifications include vascular endothelial dysfunction and arterial stiffness. Vascular endothelial dysfunction is an initiating step in atherosclerosis, and is primarily caused by reduced nitric oxide (NO) bioavailability secondary to excessive superoxide-driven oxidative stress and inflammation. Endothelial dysfunction leads to arterial stiffness and the development of hypertension (HTN) which further increases CVD. Greater than 2/3 of the US population has elevated blood pressure or stage 1-HTN. As such, interventions that improve vascular endothelial dysfunction by increasing NO bioavailability and mitigating excessive oxidative stress and inflammation are needed. Blueberries are rich in bioactive compounds including flavonoids, phenolic acids, and pterostilbene. These compounds and their metabolites have been shown to attenuate oxidative stress and inflammation. The primary goal of this study is to assess the efficacy of blueberries to improve reduce blood pressure and improve vascular endothelial dysfunction and arterial stiffness in middle-aged/older men with elevated blood pressure or stage 1-HTN.
Interventions
DIETARY_SUPPLEMENTBlueberry Powder
22 g/day wild blueberry powder
DIETARY_SUPPLEMENTPlacebo Powder
22 g/day placebo powder
Sponsors
Colorado State University
Wild Blueberry Association of North America
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
MALE
Age
45 Years to 70 Years
Healthy volunteers
Yes
Inclusion criteria
* Men and postmenopausal women * Aged 45-70 years * Elevated blood pressure or stage 1-Hypertension * Ability to provide informed consent
Exclusion criteria
* Have had a menstrual cycle within the past year * Blood Pressure \< 120 (systolic BP) or ≥ 140/90 mm Hg * Reactive hyperemia index \> 3.00% * Taking \> 1 antihypertensive medication, taking 1 antihypertensive medication more than 1 time per day, and/or taking the antihypertensive medication for \< 3 months * Diagnosed cancer, cardiovascular disease, diabetes, or gastrointestinal, kidney, liver, lung, and/or pancreatic disease * Triglycerides \> 350 mg/dL, low-density lipoprotein cholesterol (LDL-C) ≥ 190 mg/dL, hemoglobin A1c ≥ 6.5%, and/or taking a lipid-lowering or glucose-lowering medication * Testosterone or estrogen replacement therapy use 6 months prior to study start * Weight change ≥ 3 kg in the past 3 months, actively trying to lose weight, or unwilling to remain weight stable throughout the study * Current smokers or history of smoking in the past 12 months * Binge and/or heavy drinker (\>3 drinks on any given occasion and/or \>7 drinks/week for women, and \>4 drinks on any given occasion and/or \>14 drinks/week for men) * Body mass index \< 18.5 or \> 40 kg/m2 * Antibiotic therapy within past two months * Allergies or contraindication to study treatments or procedures
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Reactive hyperemia index | Baseline to 12 Weeks | Endothelial function assessed as reactive hyperemia index using peripheral arterial tonometry (EndoPat) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Augmentation index | Baseline to 12 Weeks | Arterial stiffness assessed as augmentation index using an automated blood pressure monitor (SphygmoCor) |
| Pulse wave velocity | Baseline to 12 Weeks | Arterial stiffness assessed as carotid-femoral pulse wave velocity using an automated blood pressure monitor (SphygmoCor) |
| Endothelial cell protein expression | Baseline to 12 Weeks | Protein expression will be assessed as an exploratory analysis for markers of nitric oxide bioavailability, inflammation, and/or oxidative stress will be measured by quantitative immunofluorescence in biopsied venous endothelial cells |
| Hemoglobin A1c | Baseline to 12 Weeks | Blood hemoglobin A1C will be measured |
| Lipid profile | Baseline to 12 Weeks | Blood lipid profiles will be measured |
| Nitric oxide metabolites | Baseline to 12 Weeks | Blood nitrate/nitrite will be measured |
| ICAM-1 | Baseline to 12 Weeks | Blood ICAM-1 will be measured |
| VCAM-1 | Baseline to 12 Weeks | Blood VCAM-1 will be measured |
| Blood pressure | Baseline to 12 Weeks | Brachial and Aortic blood pressure (systolic blood pressure, diastolic blood pressure, pulse pressure, aortic pressure) assessed using an automated blood pressure monitor (SphygmoCor) |
| Gut microbiota | Baseline to 12 Weeks | Determine the effects on stool sample microbial populations |
| Plasma blueberry polyphenol metabolites | Baseline to 12 Weeks | Targeted analysis of plasma metabolites by GC-MS and LC-MS |
Countries
United States
Outcome results
None listed