ABSTRACT
Aging impairs arterial function through oxidative stress and diminished nitric oxide (NO) bioavailability. Life-long caloric restriction (CR) reduces oxidative stress, but its impact on arterial aging is incompletely understood. We tested the hypothesis that life-long CR attenuates key features of arterial aging. Blood pressure, pulse wave velocity (PWV, arterial stiffness), carotid artery wall thickness and endothelium-dependent dilation (EDD; endothelial function) were assessed in young (Y: 5-7 month), old ad libitum (Old AL: 30-31 month) and life-long 40% CR old (30-31 month) B6D2F1 mice. Blood pressure was elevated with aging (P < 0.05) and was blunted by CR (P < 0.05 vs. Old AL). PWV was 27% greater in old vs. young AL-fed mice (P < 0.05), and CR prevented this increase (P < 0.05 vs. Old AL). Carotid wall thickness was greater with age (P < 0.05), and CR reduced this by 30%. CR effects were associated with amelioration of age-related changes in aortic collagen and elastin. Nitrotyrosine, a marker of cellular oxidative stress, and superoxide production were greater in old AL vs. young (P < 0.05) and CR attenuated these increase. Carotid artery EDD was impaired with age (P < 0.05); CR prevented this by enhancing NO and reducing superoxide-dependent suppression of EDD (Both P < 0.05 vs. Old AL). This was associated with a blunted age-related increase in NADPH oxidase activity and p67 expression, with increases in superoxide dismutase (SOD), total SOD, and catalase activities (All P < 0.05 Old CR vs. Old AL). Lastly, CR normalized age-related changes in the critical nutrient-sensing pathways SIRT-1 and mTOR (P < 0.05 vs. Old AL). Our findings demonstrate that CR is an effective strategy for attenuation of arterial aging.
