Association of Oxidative Stress with Aortic Stiffness in Hypertensive Patients with Chronic Kidney Disease

Abstract

Several studies have consistently demonstrated that arterial stiffness becomes progressively worse as CKD progresses and a negative correlation of oxidative stress with renal function has been described. There is also sound experimental evidence indicating that oxidative stress is involved in atherogenesis. The contribution of oxidative stress to aortic stiffness is less clear. Aim: To analyse the relationship between plasma levels of 8-ISO-prostaglandin F2alpha (8-ISOPGF2alpha), an index of lipid peroxidation, considered a reliable biomarker of oxidative stress, and aortic stiffness in a group of hypertensive patients with chronic kidney disease. Methods: We enrolled 126 hypertensive patients (mean age 58 – 13 years, males 56%) with CKD. In all the subjects 24-hour urine collection was performed to determine albuminuria and routine biochemical parameters and 8-ISO-PGF2alpha plasma values, measured by an enzyme-linked immunosorbent assay, were obtained. Moreover, ambulatory blood pressure monitoring and measurement of c-f PWV, by a computerized automatic method (Arteriograph), were performed. The GFR was estimated by the four-variable MDRD study equation. Results: The mean value of eGFR was 44 – 26mL/min/1.73m2). The patients with elevated values of c-f PWV (>12m/sec) showed significantly higher 8-ISO-PGF2alpha plasma levels than those of subjects with PWV <12m/sec (p < 0.01). A statistical significant correlation was found between 8-ISO-PGF2alpha and c-fPWVin the whole study population (r = 0.33; p = 0.001). This association held even after adjustment for age, gender, mean arterial pressure, smoking habit, glycaemia, total cholesterol, calcium phosphate product and eGFR (beta = 0.23; p = 0.006) in a stepwise multiple regression model. Conclusions: Our results seem to suggest that in hypertensive subjects with CKD there is an independent relationship between oxidative stress and aortic stiffness and that the unfavourable influence of a reduced renal function on large artery elastic properties may be partly mediated by an increased oxidative stress.