ANTIOXIDANT STATUS IN CONTROLLED AND UNCONTROLLED HYPERTENSION AND ITS RELATIONSHIP TO ENDOTHELIAL DAMAGE

Hypertension is associated with an increased risk of atherosclerosis. Free radical oxidative damage has been implicated in the atherogenic p rocess. We measured levels of the antioxidants uric acid, thiols, vita mins C, A and E as well as the total antioxidant capacity in 21 normot ensive controls, 22 patients whose hypertension was controlled on drug s and 30 patients with uncontrolled hypertension. Mean BPs in the grou ps were 125/76, 132/80 and 181/98 mmHg, respectively. When compared wi th controls, both hypertensive groups had significantly lower serum as corbic acid (54+/-5 vs. 37+/-6 vs. 38+/-5 mu mol/l, P<<0.05) and album in-corrected thiol levels (9.91 +/- 0.18 vs. 8.69 +/- 0.20 vs. 8.92 +/ - 0.19 mu mol/g, P<0.05). the levels of the other antioxidants did not differ significantly between the groups. Levels of von Willebrand fac tor, a marker of endothelial damage, were correlated with SBP but not with antioxidant status. We conclude that hypertensive subjects have l ower levels of the antioxidants vitamin C and thiols and this may refl ect greater oxidative consumption. The implications for atherogenesis and endothelial function and integrity in hypertension are discussed.