Caloric restriction enhances vascular tone of cerebral and mesenteric resistance arteries in aged rats

Vascular changes of tone and biomechanical properties induced by ageing increase the risk for cardiovascular diseases. Caloric restriction (CR) has been shown to protect against cardiovascular diseases and improve endothelial dysfunction in cerebral resistance arteries. We hypothesise that CR will enhance vascular tone and structural properties of cerebral resistance arteries and exert comparable beneficial effects on the systemic vasculature of aged rat model. Eighteen-month-old male Sprague-Dawley rats were feed either ad libitum or restricted to 60 % of calorie consumption up to 24 months of age, when body weight (BW) measurements were taken and functional and structural properties of resistance arteries were assessed using a pressure myograph. In cerebral arteries, CR increased myogenic tone (p < 0.001) and distensibility (p < 0.01) in response to intraluminal pressure and concentration-dependent constriction to KCl (p < 0.001). In mesenteric arteries constriction in response to KCl was increased (p < 0.0001) and wall thickness reduced (p < 0.01) in CR rats. BW was reduced (p < 0.0001) in FR rats. Our findings demonstrate that CR improves vascular tone of resistance arteries regardless the type of stimulus and independently of the vascular bed. CR may be a beneficial dietary approach to prevent age-related vascular diseases.