Microvascular Alterations in Hypertension and Vascular Aging.

Hypertension and aging are characterized by vascular remodelling and stiffness as well as endothelial dysfunction. Endothelial function declines with age, since aging is associated with senescence of the endothelium due to increased rate of apoptosis and reduced regenerative capacity of the endothelium. Different phenotypes of hypertension have been described in younger and adult subjects with hypertension. In younger patients, functional and structural alterations of resistance arteries occur as the earliest vascular alterations which have prognostic significance and may contribute to stiffness of large arteries through wave reflection. In individuals above age of 50 years as well as in subjects with long-lasting elevated blood pressure, vascular changes occur predominantly in conduit arteries which become stiffer. Activation of renin-angiotensin-aldosterone and endothelin systems plays a key role in endothelial dysfunction, vascular remodelling, and aging by inducing reactive oxygen species production, and promoting inflammation and cell growth.