Local renin-angiotensin system mediates endothelial dilator dysfunction in aging arteries.

LOCAL RENIN-ANGIOTENSIN SYSTEM MEDIATES ENDOTHELIAL DILATOR DYSFUNCTION IN AGING ARTERIES. Am J Physiol Heart Circ Physiol. 2016 Jul 15;:ajpheart.00422.2016 Authors: Flavahan S, Chang F, Flavahan NA Abstract Aging impairs endothelium-dependent NO-mediated dilatation, which results from increased production of reactive oxygen species (ROS). The local generation of angiotensin II (ANGII) is increased in aging arteries and contributes to inflammatory and fibrotic activity of smooth muscle cells and arterial wall remodeling. Although prolonged in vivo ANGII inhibition improves the impaired endothelial dilatation of aging arteries, it is unclear whether this reflects inhibition of intravascular or systemic ANGII systems. Experiments were therefore performed on isolated tail arteries from young (3-4 months) and old (22-24 months) F344 rats to determine if a local renin-angiotensin system contributes to the endothelial dilator dysfunction of aging. Aging impaired dilatation to the endothelial agonist, acetylcholine, but did not influence responses to a NO donor (DEA NONOate). Dilatation to acetylcholine was greatly reduced by NO synthase inhibition (LNAME) in young and old arteries. In isolated arteries, acute inhibition of angiotensin converting enzyme (ACE) (perindoprilat), renin (aliskiren) or AT1 receptors (valsartan, losartan) did not influence dilatation to acetylcholine in young arteries, but increased responses in old arteries. Afte...
Source: American Journal of Physiology. Heart and Circulatory Physiology - Category: Physiology Authors: Tags: Am J Physiol Heart Circ Physiol Source Type: research