Abstract TP451: Age-associated Changes in the Structure and Biomechanical Properties of Parenchymal Arterioles
Arterial aging, a phenomenon that we do not fully understand, results in dysfunctional arteries. Age-associated changes in physiological and vascular functions increase the risk of cardiovascular disease. Aging results in peripheral artery remodeling, described as a change in artery size and wall structure. Age-related cerebral artery remodeling could increase the risk of stroke and vascular dementia particularly in situations where comorbidities, such as hypertension, are present. The effects of aging on the biomechanical properties of parenchymal arterioles (PAs) have not been characterized. PAs regulate perfusion of the cerebral microcirculation and are important in determining cerebrovascular resistance. We hypothesized that aging would decrease the lumen diameter, and increase the wall thickness and collagen deposition in PAs from C57Bl/6 mice. PAs were collected from 3-5 month (young; n=8) and 22-24 month (old; n=8) old male mice for assessment of structure by pressure myography. Data collected at 60mmHg are presented as mean ± SEM, young vs. old. Advanced age was associated with increased systolic blood pressure (126 ± 1 vs 145 ± 2mmHg). Aging did not significantly affect the outer (49 ± 5 vs 53 ± 3μm) or lumen (41 ± 5 vs 41 ± 2μm) diameter of the PAs (p > 0.05 for all comparisons). However, the PAs from older mice had increased wall thickness (4 ± 1 vs 6 ± 1μm), wall area (591 ± 96 vs 853 ± 101μm2), and wall-to-lumen ratio (0.10 ± 0.01 vs 0.13 ± 0.01) (p < 0.05 for all comparisons). Wall stress (302 ± 27 vs 220 ± 11 dynes/cm2) was reduced with age. Changes in artery wall structure have been associated with modifications in the components of the extracellular matrix such as collagen and calcium. The PAs from older mice had increased collagen deposition in the wall (427 ± 172 vs 2699 ± 442μm2; p < 0.05) but the number of arteries with calcium deposits was similar between groups (2 ± 1 vs 3 ± 1 positive vessels/area; p > 0.05). Our studies of geriatric mice with high blood pressure suggest that aging is associated with hypertrophic remodeling of the PAs that is accompanied by alterations in the extracellular matrix of the artery wall; these changes could increase the risk of cerebrovascular diseases.
Author Disclosures: J.M. Diaz-Otero: None. W.F. Jackson: None. A.M. Dorrance: None.
This research has received full or partial funding support from the American Heart Association, Midwest Affiliate – Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, South Dakota, Wisconsin.
- © 2016 by American Heart Association, Inc.