Abstract P285: Aging In Male Mice Is Characterized By Arterial Stiffening And Diastolic Dysfunction
Aging is a nonmodifiable risk factor for cardiovascular mortality and is associated with arterial stiffening and cardiac dysfunction. In this study, we hypothesized that aging would decrease vascular compliance and cardiac function in male mice. Tail-cuff plethysmography was used to measure blood pressure, pulse wave velocity (PWV) for arterial stiffness, echocardiography for systolic and diastolic cardiac function, and wire myography for vessel reactivity in mature adult (25 weeks) and middle-aged (57 weeks) C57Bl/6 mice. Data was analyzed by t-test or 2-way ANOVA, and P<0.05 was considered significant. While there was no difference in blood pressure, PWV was higher in middle-aged male mice (1.8 ± 0.04 m/s vs. 1.2 ± 0.05 m/s; P<0.001) and associated with increased left ventricular (LV) posterior wall thickness (1.4 ± 0.07 mm vs. 1.1 ± 0.13 mm; P=0.03), and LV mass (172 ± 8 mg vs. 158 ± 20 mg; P=0.04). The ratio of early to late filling velocities, a measure of diastolic function, was lower in middle-age (1.6 ± 0.07 vs. 2.7 ± 0.37; P<0.001). Carotid artery histological analysis indicated that middle-aged mice had a greater collagen-to-elastin ratio along with decreased amounts of smooth muscle and thin collagen (P<0.05). Mesenteric artery contraction to PGF2α (446 ± 15% vs. 378 ± 14%; P=0.02) as well as relaxation to sodium nitroprusside (55 ± 7% vs. 31 ± 7%; P<0.01) were both blunted in the middle-aged group. The current study demonstrates that aging in male mice increases arterial stiffening and LV remodeling while decreasing diastolic and vascular function, independent of increased blood pressure. Future studies will investigate whether strategies that counteract arterial stiffness in the absence of changes in blood pressure can protect from cardiovascular aging.