Regulation of Endothelial Progenitor Cells by Short-Term Exercise

Study Overview
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Brief Summary
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Endothelial Progenitor Cells (EPCs) are circulating cells released from bone marrow which are important for maintaining cardiovascular health. The prevalence of cardiovascular disease in older adults is associated with reduced circulating EPC numbers. Studies have shown reduced EPC number and function in old vs. young individuals, and endurance exercise training increases EPC number and function in young adults. Oxidative stress adversely affects endothelial cells and preliminary evidence indicates that oxidative stress negatively affects EPC function. Conversely, regular exercise reduces markers of oxidative stress and may enhance EPC function in older adults. The investigators hypothesize that older endurance-trained athletes and matched sedentary individuals will have markedly divergent EPC function and that altering the physical activity levels of both groups will move them to intermediate points between these two extremes. The investigators also propose that the investigators can mimic the effect of exercise training on EPC function in cell culture by altering intracellular levels of a key enzyme and a signaling molecule which the investigators have shown to regulate EPC function with respect to exercise training in young individuals.

Official Title
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Regulation of Endothelial Progenitor Cells by Short-Term Exercise

Conditions
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Aging, Exercise, Cardiovascular Disease

Intervention / Treatment
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* Other: Exercise Training
* Other: Exercise Cessation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 50-80 years of age, BMI = 18-35 kg/m2, non-smoking, women must be postmenopausal Exclusion Criteria: history of cardiovascular/cerebrovascular disease, diabetes, cancer, renal, liver disease, HIV; uncontrolled hyperlipidemia/hypertension

Ages Eligible for Study
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Minimum Age: 50 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Sedentary Older Adults<br> | Other: Exercise Training<br>* 2 weeks of daily aerobic exercise training<br>|
| Experimental: Older Endurance Athletes<br> | Other: Exercise Cessation<br>* Stopping all exercise for 2 weeks<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Baseline Endothelial progenitor cell number |  | Day 1 | 
| Final Endothelial Progenitor Cell Number |  | Day 15 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Baseline Endothelial Reactivity |  | Day 1 | 
| Final Endothelial Reactivity |  | Day 15 |