Aging and total stenosis triggers differential responses of carotid and basilar arteries to endothelin-1 and phenylephrine

Endothelial cell senescence in aging-related vascular dysfunction

Increased cardiovascular disease in aging is partly a consequence of the vascular endothelial cell (EC) senescence and associated vascular dysfunction. In this contest, EC senescence is a pathophysiological process of structural and functional changes including dysregulation of vascular tone, increased endothelium permeability, arterial stiffness, impairment of angiogenesis and vascular repair, and a reduction of EC mitochondrial biogenesis. Dysregulation of cell cycle, oxidative stress, altered calcium signaling, hyperuricemia, and vascular inflammation have been implicated in the development and progression of EC senescence and vascular disease in aging. A number of abnormal molecular pathways are associated with these underlying pathophysiological changes including Sirtuin 1, Klotho, fibroblast growth factor 21, and activation of the renin angiotensin-aldosterone system. However, the molecular mechanisms of EC senescence and associated vascular impairment in aging are not completely understood. This review provides a contemporary update on molecular mechanisms, pathophysiological events, as well functional changes in EC senescence and age-associated cardiovascular disease. This article is part of a Special Issue entitled: Genetic and epigenetic regulation of aging and longevity edited by Jun Ren & Megan Yingmei Zhang.

Vascular biology of ageing-Implications in hypertension

Ageing is associated with functional, structural and mechanical changes in arteries that closely resemble the vascular alterations in hypertension. Characteristic features of large and small arteries that occur with ageing and during the development of hypertension include endothelial dysfunction, vascular remodelling, inflammation, calcification and increased stiffness. Arterial changes in young hypertensive patients mimic those in old normotensive individuals. Hypertension accelerates and augments age-related vascular remodelling and dysfunction, and ageing may impact on the severity of vascular damage in hypertension, indicating close interactions between biological ageing and blood pressure elevation. Molecular and cellular mechanisms underlying vascular alterations in ageing and hypertension are common and include aberrant signal transduction, oxidative stress and activation of pro-inflammatory and pro-fibrotic transcription factors. Strategies to suppress age-associated vascular changes could ameliorate vascular damage associated with hypertension. An overview on the vascular biology of ageing and hypertension is presented and novel molecular mechanisms contributing to these processes are discussed. The complex interaction between biological ageing and blood pressure elevation on the vasculature is highlighted. This article is part of a Special Issue entitled: CV Ageing.

The effects of aging on the functional and structural properties of the rat basilar artery

Aging leads to progressive pathophysiological changes in blood vessels of the brain and periphery. The aim of this study was to evaluate the effects of aging on cerebral vascular function and structure. Basilar arteries were isolated from male Fischer 344 cross Brown Norway (F344xBN) rats at 3, 8, and 24 months of age. The basilar arteries were cannulated in the pressurized system (90 cm H₂O). Contractile responses to KCl (30–120 mmol/L) and endothelin‐1 (10⁻¹¹–10⁻⁷ mol/L) were evaluated. Responses to acetylcholine (ACh) (10⁻¹⁰–10⁻⁴ mol/L), diethylamine (DEA)‐NONO‐ate (10⁻¹⁰–10⁻⁴ mol/L), and papaverin (10⁻¹⁰–10⁻⁴ mol/L) were assessed to determine both endothelium‐dependent and endothelium‐independent responsiveness. Advanced aging (24 months) decreased responses of the basilar artery to both the contractile and relaxing agents; whereas, DEA‐induced dilation was significantly higher in the 8‐month‐old group compared with the younger and older groups. The arterial wall‐to‐lumen ratio was significantly increased in 24‐month‐old rats. Smooth muscle cell count was also decreased in old rats. These findings indicate that aging produces dysfunction of both the endothelium and the vascular smooth muscle in the basilar artery. Aging also alters wall structure of the basilar artery, possibly through decreases in smooth muscle cell number and concomitant hypertrophy.

The purpose of this study was to determine the effects of advancing age on the structure and vasomotor responses of the basilar artery as well as the serum antioxidant capacity. Advanced aging (24 months) decreased responses of the basilar artery to both the contractile and relaxing agents, whereas, DEA‐induced dilation was significantly higher in the 8‐month‐old group compared with the younger and older rats. The arterial wall‐to‐lumen ratio was significantly increased in 24‐month‐old rats. Smooth muscle cell count was also decreased in old rats. Our findings demonstrate that aging is associated with functional impairment in endothelium‐dependent and ‐independent relaxation responses and contractility in the basilar arteries, and these diminished responses are accompanied by structural remodeling and decreased antioxidant capacity of the serum.