S-nitrosothiols do not induce oxidative stress, contrary to other nitric oxide donors, in cultures of vascular endothelial or smooth muscle cells

Nitric oxide (NO) has been described to exert various anti-atherogenic acti ons. However, NO, in some cases, has been shown to stimulate the oxidation of low-density lipoprotein (LDL), which constitute an important triggering event in atherosclerosis. Thus, some NO donors, despite their advantages, m ight also induce oxidative stress. Therefore, the put-pose of this study is to examine the effect of three different NO donors on LDL oxidation, in ac ellular system as well as in cultures of normal endothelial cells or smooth muscle cells, which constitute the two major cellular components of the ar terial wall. Sodium nitroprusside oxidized strongly LDL in medium alone as well as in endothelial or smooth muscle cell cultures. Sydnonimine-1 (SIN-1 ) oxidized LDL already in the absence of cells and enhanced clearly the LDL oxidation in the cultures. S-nitroso-N-acetylpenicillamine was unable to o xidize LDL in synthetic medium alone as well as in the presence of cells, s howing that the amount of superoxide and other reactive oxygen species rele ased by these cells did not suffice, contrary to those liberated by macroph ages, to combine to NO providing oxidant activity. (C) 2001 Elsevier Scienc e B.V. All rights reserved.