[Age-related changes in the renin-angiotensin-aldosterone system and the sympathetic nervous system in patients with essential hypertension].

The aim of this study was to evaluate age, plasmatic renin activity (PRA), plasma aldosterone levels and the total quantity of urinary catecholamines (TOT. UR. CAT.) in a large population of out-patients suffering from essential arterial hypertension (EAH). A total of 986 patients were examined (540 women and 426 men aged between 15 and 87 years) suffering form slight or moderate EAH (WHO stage 1-2). After a wash-out period of two weeks, systolic and diastolic arterial pressure was measured together with heart rate in clino- and orthostatism. Blood samples were collected to determine PRA and plasma aldosterone, and lastly a 24-hour urine collection was made to measure the total quantity of catecholamines. It emerged that there was a significant increase in systolic pressure, whereas heart rate and PRA diminished significantly when correlated with age; diastolic pressure was also considerably lower, but did not reach statistical significance. Moreover, it was found that there was a significant positive correlation between PRA and TOT. UR. CAT., whereas no correlation was found between age and plasma aldosterone and between blood pressure and the various endocrine parameters examined. These data confirm the changes in the biological, hemodynamic and endocrine profiles observed in elderly hypertensive patients in comparison to young hypertensive patients, and suggests that age may be an important predictive factor of the activity of both the renin-angiotensin and sympathetic nervous system which appear to be closely connected and gradually attenuated by age.