Systemowa równowaga antyoksyacyjna u pacjentów bez klinicznej manifestacji miażdżycy

Abstract

Introduction. Oxidative stress plays an important role in atherosclerosis, but numerous clinical trials have not confirmed a favourable effect of antioxidant supplementation. We aimed to determine the oxidative stress parameters in patients without clinical manifestation of vascular disease. Material and methods. Forty-eight patients were divided into two groups in relation to the presence or absence of clinically silent signs of atherosclerosis (ankle-brachial index < 0.9, intima-media thickness ≥ 0.9 mm, the presence of carotid atherosclerotic plaques, silent ischaemia in a treadmill stress test or focal myocardial contractility found in echocardiography). Plasma concentrations of: retinol, ascorbic acid, alpha-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 leucocytes and urine, and 8-oxo-7,8-dihydroguanine (8-oxo-Gua) in urine. Results. Patients with signs of subclinical atherosclerosis had lower blood concentration of alpha-tocopherol, and a non-significantly greater urine concentration of 8-oxoGua. Women had significantly greater blood concentration of ascorbic acid and alpha-tocopherol, as well as lower level of retinol and uric acid. They also had greater leucocyte concentration of 8-oxodG. Plasma concentration of alpha-tocopherol 30.34 μM distinguished patients with and without signs of subclinical atherosclerosis. Conclusions. Oxidative stress has clinical importance in the early stages of atherosclerosis and may be helpful in predicting its subclinical stage. Women had higher level of antioxidant defence, which explains their natural protection against early atherosclerosis development. Further studies are needed to determine the usefulness of tocopherol determination as a biomarker for atherosclerosis risk evaluation.