Aging is inevitable and is the primary risk factor for developing cardiovascular disease. The molecular mechanisms that drive vascular dysfunction in the context of aging are incompletely understood. The overall hypothesis is that the age-related decline in endothelial cell (EC) autophagy leads to arterial dysfunction. This study will determine whether physiological shear-stress affects autophagosome formation and nitrous oxide (NO) generation in ECs.
It is hypothesized that genetic autophagy suppression prevents shear-stress induced purinergic signaling to endothelial nitrous oxide synthase (eNOS) and this pathway will be evaluated in primary arterial ECs obtained from older adult (\> 60 years) and adult (18-30 years) subjects before and following rhythmic handgrip exercise that elevates brachial artery shear-rate similarly in both groups. ECs will be used to quantify markers of EC autophagy, eNOS activation, and NO generation. The study will also determine whether exercise-training attenuates the aging-associated decline in EC autophagy, and whether intact autophagy is required for training-induced vascular improvements. To evaluate this potential, it will be determined whether one-limb rhythmic handgrip exercise training by older adult (\> 60 y) human subjects is sufficient to elevate basal and shear-induced EC autophagy initiation, eNOS activation, and NO generation vs. the contralateral sedentary limb. Results from this work have tremendous potential to reveal a new therapeutic target and approach for restoring / maintaining vascular function in the aging population.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
16
60 minute rhythmic handgrip exercise
Handgrip exercise training consisting of three 60-minute training sessions per week for eight weeks.
VA Medical Center
Salt Lake City, Utah, United States
Change in biomarker beclin-1 after Rhythmic Handgrip Exercise
Time frame: 60 min
Change in biomarker Atg3 after Rhythmic Handgrip Exercise
Time frame: 60 min
Change in biomarker Atg5 after Rhythmic Handgrip Exercise
Time frame: 60 min
Change in biomarker Atg7 after Rhythmic Handgrip Exercise
Time frame: 60 min
Change in biomarker Lamp1 after Rhythmic Handgrip Exercise
Time frame: 60 min
Change in biomarker Lamp2 after Rhythmic Handgrip Exercise
Time frame: 60 min
Change in biomarker p62 after Rhythmic Handgrip Exercise
Time frame: 60 min
Change in biomarker beclin-1 after chronic exercise training
Time frame: 8 weeks
Change in biomarker Atg3 after chronic exercise training
Time frame: 8 weeks
Change in biomarker Atg5 after chronic exercise training
Time frame: 8 weeks
Change in biomarker Atg7 after chronic exercise training
Time frame: 8 weeks
Change in biomarker Lamp1 after chronic exercise training
Time frame: 8 weeks
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Change in biomarker Lamp2 after chronic exercise training
Time frame: 8 weeks
Change in biomarker p62 after chronic exercise training
Time frame: 8 weeks
Change in radial arterial diameter after Rhythmic Handgrip Exercise
Time frame: 60 min
Change in radial arterial flow rate after Rhythmic Handgrip Exercise
Time frame: 60 min
Change in biomarker p-eNOSS1177 after Rhythmic Handgrip Exercise
Time frame: 60 min
Change in radial arterial diameter after chronic exercise training
Time frame: 8 weeks
Change in radial arterial flow rate after chronic exercise training
Time frame: 8 weeks
Change in biomarker p-eNOSS1177 after chronic exercise training
Time frame: 8 weeks