CALL FOR PAPERS Small Vessels–Big Problems: Novel Insights into Microvascular Mechanisms of Diseases Aging is associated with changes to the biomechanical properties of the posterior cerebral artery and parenchymal arterioles

Diaz-Otero JM, Garver H, Fink GD, Jackson WF, Dorrance AM. Aging is associated with changes to the biomechanical properties of the posterior cerebral artery and parenchymal arterioles. Am J Physiol Heart Circ Physiol 310: H365–H375, 2016. First published December 4, 2015; doi:10.1152/ajpheart.00562.2015.—Artery remodeling, described as a change in artery structure, may be responsible for the increased risk of cardiovascular disease with aging. Although the risk for stroke is known to increase with age, relatively young animals have been used in most stroke studies. Therefore, more information is needed on how aging alters the biomechanical properties of cerebral arteries. Posterior cerebral arteries (PCAs) and parenchymal arterioles (PAs) are important in controlling brain perfusion. We hypothesized that aged (22–24 mo old) C57bl/6 mice would have stiffer PCAs and PAs than young (3–5 mo old) mice. The biomechanical properties of the PCAs and PAs were assessed by pressure myography. Data are presented as means SE of young vs. old. In the PCA, older mice had increased outer (155.6 3.2 vs. 169.9 3.2 m) and lumen (116.4 3.6 vs. 137.1 4.7 m) diameters. Wall stress (375.6 35.4 vs. 504.7 60.0 dyn/cm) and artery stiffness ( -coefficient: 5.2 0.3 vs. 7.6 0.9) were also increased. However, wall strain (0.8 0.1 vs. 0.6 0.1) was reduced with age. In the PAs from old mice, wall thickness (3.9 0.3 vs. 5.1 0.2 m) and area (591.1 95.4 vs. 852.8 100 m) were increased while stress (758.1 100.0 vs. 587.2 35.1 dyn/cm) was reduced. Aging also increased mean arterial and pulse pressures. We conclude that ageassociated remodeling occurs in large cerebral arteries and arterioles and may increase the risk of cerebrovascular disease.