Role of Aging and Exercise on Arterial Remodeling in Mice

Introduction: Arterial stiffness is a significant age-related disease that can be attenuated by exercise. The objective of this study was to test murine mechanics of young (12-20 week old) and old (80 week old) carotid and... [ view full abstract ]

Introduction: Arterial stiffness is a significant age-related disease that can be attenuated by exercise. The objective of this study was to test murine mechanics of young (12-20 week old) and old (80 week old) carotid and femoral arteries in animals allowed to exercise compared to those that did not.
Methods: Male mice were caged with running wheels or not for four weeks and rotations/hour were captured. Carotid (elastic artery) and femoral (muscular) arteries were harvested and ex vivo biaxial mechanics were calculated between age groups and segregated by exercise or not.
Results: Aging significantly decreased the physiologic stress (longitudinal stiffening) of both the carotid and femoral arteries. Aging, but not exercise, increased the caliber of the femoral but not carotid arteries, and in the non-exercise groups, aging significantly increased stiffness in both femoral and carotid arteries. Aged animals exercised significantly less than their younger counterparts [4.1 (4.6) versus 17 (2.6) rotations/hour; P=.0006]. Despite decreased exercise effort, femoral arteries from the old mice were more compliant with exercise, while both young and old carotid arteries were not affected by exercise. (Figure)
Conclusions: Aging significantly stiffens carotid and femoral arteries in mice. However exercise only attenuates age-related stiffening in the femoral arteries. This work supports the idea that exercise (even if less robust in aged animals) preferentially improves the muscular arteries of the leg. This may be important in understanding the benefits of exercise in patients with peripheral arterial disease.