Actions of Selected Cardiovascular Hormones on Arterial Stiffness and Wave Reflections

Abstract

The large conduit arteries of the thorax and abdomen are elastic while those in the arms and legs are muscular. Alterations in wall properties of elastic arteries occur over time and are usually permanent in nature; acute changes can, however, occur is response to a change in transmural pressure. Chronic alterations in properties of muscular arteries are minimal but changes (e.g vasoconstriction, vasodilation or tone) do occur in response to smooth muscle cell (SMC) stimulation. In general an increase in arterial stiffness (and wave reflection) increases systolic blood pressure (BP) and is detrimental while a decrease is beneficial. The augmentation in systolic BP increases left ventricular (LV) mass, wasted energy, tension-time index (TTI) and myocardial oxygen demand while the fall in diastolic BP decreases coronary artery perfusion causing a mismatch in ventricular/vascular coupling and an imbalance in the myocardial oxygen supply/demand ratio. Cardiovascular hormones such as renin, angiotensin, aldosterone, parathormone, sympathomimetic amines and endothelin induce vasoconstriction and increase arterial stiffness while insulin, thyroxine, testosterone, atrial natriuretic peptide (ANP), estrogen and nitric oxide (NO) have the opposite effect. The undesirable effects can be reversed with selected blocking agents. Vasodilator drugs have little direct active effect on large elastic arteries and unaugmented BP but can markedly reduce wave reflection amplitude and duration and augmentation index by decreasing stiffness of the muscular arteries and reducing transmission velocity of the reflected wave from the periphery to the heart. This decrease in amplitude and increase in travel time (or delay) of the reflected wave causes a generalized decrease in systolic BP, arterial wall stress, wasted LV energy and TTI.

Effects of resistance exercise training on resting and post-exercise forearm blood flow and wave reflection in overweight and obese women

“…37,38 Furthermore, it has been suggested that estrogen improves endothelial function. 12,39 Therefore, it is feasible that the premenopausal status of our participants may have influenced the beneficial effect of RET on arm vasodilatory capacity.…”

“…8 Chronic exercise, in particular, resistance exercise training (RET), has been suggested to improve endothelial function, [9][10][11] by increasing FBF and vasodilatory capacity, which in turn may decrease the AIx. Improving the arterial function is of clinical importance because an increased AIx imposes an overload to the left ventricle that promotes myocardial hypertrophy, 12,13 a main predictor of cardiovascular morbidity and mortality. 14 Acute upper-body resistance exercise increases FBF and vasodilatory capacity to reactive hyperemia (RH) in healthy young adults.…”

Short-term effects of l-citrulline supplementation on arterial stiffness in middle-aged men

“…Arterial stiffness is regulated by numerous factors such as NO. Mean arterial pressure and structural changes in the components of the arterial wall were once thought to be the main determinants of arterial stiffness, however it is now recognized that arterial stiffness is also regulated by vascular tone and that endothelium derived mediators, such as NO, contribute to the functional regulation of arterial stiffness [6].…”

Hormones and Arterial Stiffness in Patients with Chronic Kidney Disease

“…AS results from the complex interplay between several independent and interdependent factors. Aging is considered to be the most important risk factor for the development of AS alongside other various changes in hemodynamic forces, salt intake, glycemic control and the overall decline in the cellular function [6][7][8][9] . In the arterial wall, aging and increased blood pressure leads to stiffening via medial degeneration that presents with fractures and fragmentation of the elastic lamellae, increased collagen and calcium content, dilation and hypertrophy of the large arteries 10) .…”