Large Artery Remodeling During Aging

Abstract

Abstract —To examine arterial mechanical changes during aging, pressure-radius and axial force–radius curves were measured in vivo in carotid arteries from 6- and 23-month-old Brown Norway X Fischer 344 rats. Incremental passive circumferential stiffness (measured at 50, 100, and 200 mm Hg) was higher ( P 2 ×10 ³ , respectively). Incremental passive axial stiffness was increased ( P 2 ×10 ³ , respectively). Active incremental circumferential arterial stiffness at 100 and 200 mm Hg was increased ( P P P P <0.05) media thickness, collagen content, and the collagen/elastin ratio by 12%, 21%, and 38%, respectively. Elastin density and the number of smooth muscle cell nuclei were decreased by 20% and 31%, respectively, with aging. Thus, structural alterations that occur with aging are associated with changes in both active and passive stiffness. Vascular smooth muscle tone modulates arterial wall anisotropy differently during aging.