Endothelial dysfunction was closely related with AS , NO bioavailability ( production and utilization of endothelial NO ) was decreased by oxidative stress , lipid infiltration , inflammatory factor expression , vascular tone alteration and so on , which play an important role in endothelial dysfunction .Enhanced arginine , activityand asym-metric dimethylarginine together with increased hyperhomocysteinemia all promote AS by intervening NO bioavail -ability.Diabetes mellitus, obesity, chronic kidney disease , smoking and so on also involved in AS via influencing NO bioavailability and NO level .