Changes in renal autacoids in aged human hypertensives

The aging process determines several modifications of the kidney, that, how ever, do not provoke any dysfunction in normal conditions. But in the elder ly - in the presence of stressful situations and particularly when adrenerg ic activation is present - the kidney is more vulnerable than in the young, and renal failure may arise. Variations typical of the aging kidney are ac celerated when hypertension overlaps the physiological renal process, becau se both senescence and hypertension weight on the same structures, i. e. gl omeruli. We studied renal hemodynamic adaptation capacity both in the healt hy elderly and in patients affected by isolated systolic hypertension, in a n acute experiment which requires the application of a mental stress-induce d adrenergic activation. In hypertensive patients we have already demonstra ted a total lack of renal adaptation capacity. In fact, while the elderly n ormotensives react with a prolonged and pronounced vasoconstriction, in tho se with isolated systolic hypertension, adrenergic activation induces a pas sive renal vasodilation and glomerular hyperfiltration. The anomalous adapt ation capacity of renal hemodynamics is probably due to an impairment in th e paracrine response of renal vasculature. Indeed in the hypertensive elder ly, unlike in the normotensive one, no variations of autacoid production oc cur during the adrenergic activation. Following on from this, pattients aff ected by isolated systolic hypertension passively suffer the many hypertens ive peaks which characterize their every day life. The altered renal autore gulation of the elderly with isolated systolic hypertension may explain the accelerated glomerulosclerosis and the greater incidence of renal damage a nd end-stage renal disease which characterize this condition. These aspects underline the primary role of the antihypertensive treatment of isolated s ystolic hypertension, not only for the prevention of cardiovascular mortali ty but also of renal damage and/or end-stage renal disease.