Systemic oxidoreductive balance and vascular function in individuals without clinical manifestation of...

Endothelial dysfunction is recognized as the earliest disorder in the development of atherosclerosis, in the pathogenesis of which oxidative stress plays a crucial role. The aim of this study was to determine the relationships between non-invasive parameters of vascular dysfunction and oxidative stress.

Forty-eight individuals without clinical manifestation of atherosclerosis were studied. The plasma concentrations of the following were determined in all 48 subjects: retinol, ascorbic acid, α-tocopherol and uric acid, as well as the products of oxidative DNA damage repair: 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in blood leukocytes and urine, and 8-oxo-7,8-dihydroguanine (8-oxoGua) in urine. The following parameters of vascular dysfunction were also examined: flow- (FMD) and nitroglycerin- (NMD) mediated dilatation of the brachial artery, pulse pressure (PP), distensibility coefficient (DC), pulsation (PI) and resistance (RI) index, carotid intima-media thickness (cIMT), and ankle-brachial index (ABI).

Individuals with an FMD value of ≥ 8.8% had significantly higher blood concentrations of antioxidative vitamins and lower concentrations of 8-oxodG in their urine and blood leukocytes than their counterparts. Blood concentration of alpha-tocopherol or ascorbic acid positively correlated with FMD, PI, RI, DC and ABI and negatively with PP and cIMT. The reverse was the case for 8-oxodG in urine and leukocytes. In multiple regression analysis, markers of oxidative DNA damage positively determined the variance in PP and ABI.

In persons without clinical manifestation of atherosclerosis, oxidative stress was an independent factor associated with vascular wall dysfunction, and a better predictor than smoking and blood concentrations of glucose, lipids and creatinine.