Oxidative stress and membrane fluidity of red blood cells in hypertensive and normotensive men: an electron spin resonance investigation.

Recent evidence indicates that oxidative stress might actively participate in the pathophysiology of hypertension, atherosclerosis, and other cardiovascular diseases. The purpose of the present study was to assess the possible link between oxidative stress and membrane fluidity in hypertensive and normotensive men. We measured the membrane fluidity (a reciprocal value of membrane microviscosity) of red blood cells (RBCs) in hypertensive and normotensive men using an electron spin resonance (ESR) and spin-labeling method. Membrane fluidity of RBCs was decreased in hypertensive men compared with normotensive men. The levels of plasma 8-Iso-prostaglandin F2alpha (8-Iso-PG F2alpha : an index of oxidative stress) were significantly higher in hypertensive men than in normotensive men. In contrast, plasma nitric oxide (NO)-metabolite levels were significantly lower in hypertensive men than in normotensive men. In the overall analysis of hypertensive and normotensive men, plasma 8-Iso-PG F2alpha levels were inversely correlated with plasma NO-metabolites. Furthermore, the reduced membrane fluidity of RBCs was associated with increased plasma 8-Iso-PG F2alpha and decreased plasma NO-metabolite levels. In a multivariate regression analysis, plasma 8-Iso-PG F2alpha was found to be an independent determinant of membrane fluidity of RBCs. The results of the present study suggest that oxidative stress might have a close correlation with the rheologic behavior of RBCs and the microcirculation in hypertensive men.