Carotid atherosclerosis in elderly hypertensive patients: potential role of endothelin and plasma antioxidant capacity.

Endothelin-1 (ET-1) and oxidative stress are involved in the development of hypertension-induced cardiovascular complications. The aim of this study was to evaluate the relationship between plasma ET-1 level and plasma antioxidant capacity and carotid atherosclerosis. In 61 treated patients with hypertension (44 women, 35 diabetics, mean age 72.4+/-7.2 years) medical histories, ambulatory blood pressure, blood tests (glucose, creatinine, cholesterol, haemoglobin A1c (HbA1c), ET-1) and common carotid artery intima-media thickness (CCA-IMT) measurement were carried out. Plasma antioxidant capacity was assessed by the ferric-reducing ability of plasma (FRAP). Subjects with diabetes presented with higher concentrations of glucose (7.01+/-2.3 vs 5.14+/-0.6 mmol l(-1), P<0.001), HbA1c (7.75+/-2.1 vs 6.1+/-1.2%, P<0.001) and ET-1 (1.36+/-0.53 vs 1.01+/-0.4 pg ml(-1), P<0.01), and lower cholesterol level (5.02+/-0.8 vs 5.86+/-1.3 mmol l(-1), P<0.01). A significant positive correlation between CCA-IMT and ET-1 plasma concentration (r=0.40, P<0.001) and reverse relationship between CCA-IMT and FRAP (r=-0.36, P<0.01) was observed. In a stepwise regression analysis, after adjustment for all confounders, CCA-IMT was independently influenced by age, systolic blood pressure (SBP), HbA1c and ET-1. When FRAP was included in the regression model, CCA-IMT was significantly influenced by age, FRAP, HbA1c and SBP. ET-1 promotes the increase in CCA-IMT contributing to the development of end-organ damage. Plasma antioxidant capacity may modulate this deleterious effect, but whether better antioxidant defence may prevent against the development of atherosclerosis remains to be elucidated.