Vascular effects of ACE inhibition by perindopril.

Hypertension and ageing are associated with decreased arterial compliance, increased thickening of the arterial wall, hypertrophy of arterial smooth muscle cells and an increase in the collagen content of the arterial wall. Increased blood pressure has been implicated as a causative factor in such adaptive vascular alterations, however, other factors, including angiotensin II and epidermal growth factor also induce one or more of these adaptations. Long term use of the angiotensin-converting enzyme (ACE) inhibitor perindopril 1 mg/kg has been shown to reduce blood pressure in spontaneous and renovascular hypertensive rats. Associated with this antihypertensive effect, perindopril completely reversed aortic medial thickening, increased arterial compliance (by 42%) and decreased aortic smooth muscle cell nucleus density (by 13%), but had no significant effect on the elastin: collagen ratio of the arterial wall. In contrast, in spontaneously hypertensive animals, perindopril partially reversed aortic medial thickening and had no significant effect on arterial compliance, despite significantly increasing the arterial wall elastin: collagen ratio in this experimental group. The effect of ACE inhibition appears to directly reflect the role of angiotensin II in the pathogenesis of different hypertensive states.