Abstract W P395: Aging Alters Vascular Stiffness in the Posterior Cerebral Artery in C57bl/6 Mice
Aging is a major risk factor for cardiovascular disease in part as a result of dysfunctional arteries. Arterial stiffening with age is considered to be an independent predictor of cardiovascular disease. Age-related artery remodeling in large conduit arteries increases the risk of stroke and dementia. Atherosclerotic elderly mice exhibit aorta outward remodeling compared to young mice. Also, peripheral resistance arteries remodel with age. Less is known on how aging alters the morphology of cerebral arteries. Historically young mice have been used in many stroke studies, however the STAIR criteria for preclinical testing clearly states that potential neuroprotective drugs need to be tested in aged mice. It is therefore important to understand how aging affects cerebral artery structure. The effects of aging have not been investigated in the posterior cerebral artery (PCA). The PCAs provide blood flow support when the middle cerebral artery is occluded or when blood flow to the brain is decreased by carotid artery stenosis. We hypothesized that aging would increase the PCA lumen diameter and wall thickness in C57BL/6 mice. PCAs were collected from 5 month (n=7) and 24 month (n=7) old mice for assessment of vessel structure by pressure myography. All results are presented as mean ± SEM, young vs old. The old mice weighed significantly more than the young mice (28.85±0.36 vs 33.27±1.04 grams p<0.05). Surprisingly, aging caused limited changes to the structure of the PCA. Statistically significant changes in the outer diameter (126.9± 2.5 vs 141.6 ± 3.3μm, ANOVA p <0.05) and lumen diameter (100.9± 2.4 vs 115.8± 3.2μm ANOVA p <0.05) where only observed at an intralumenal pressure of 20mmHg. Changes observed at such a low intralumenal pressure are unlikely to be physiologically relevant. Aging had no effect on the wall-to-lumen ratio, wall thickness, or distensibility. Aging did increase artery stiffness assessed by calculating the slope of the individual stress strain curves (beta coefficient: 5.13± 0.42 vs 6.71± 0.42, t-test p <0.05). Increased artery stiffness is associated with an increased risk of cardiovascular disease. In the absence of a change in the wall thickness this increased stiffness is likely to be due to changes in extracellular matrix deposition.
Author Disclosures: J.M. Diaz-Otero: None. W.F. Jackson: None. A.M. Dorrance: None.
- © 2015 by American Heart Association, Inc.