Doxazosin, an alpha1-adrenergic antihypertensive agent, decreases serum oxidized LDL

Oxidized low-density lipoprotein (ox-LDL) is well known to play an important role in atherogenesis through the recruitment of monocytes into vessel walls and the deposition of cholesterol ester in the macrophages, which leads to the formation of lipid-rich plaque. It was assumed that only trace amounts of ox-LDL were present in plasma because the half-life of ox-LDL was only a few minutes. Recently, through the use of a monoclonal antibody against ox-LDL, a quantitative method to measure serum ox-LDL concentration has been developed. Metabolites of doxazosin, an alpha1-adrenergic antihypertensive agent, have been reported to inhibit oxidation of LDL in vitro. In this study, we investigated the in vivo effect of doxazosin on LDL oxidation using this new method to measure serum ox-LDL concentration. After the administration of doxazosin for 1 to 2 months, serum concentration of ox-LDL decreased significantly (P < .05). Although the reduction of ox-LDL concentration does not strictly indicate doxazosin's antiatherosclerotic effect, it may constitute one of doxazosin's additional weapons beside lowering blood pressure and serum lipid values in the prevention of atherosclerosis.