Impaired fibrinolytic and blunted nitric oxide response to phlebotomy in cigarette smoking healthy blood donors.

This study was designed to investigate the effects of smoking on endothelial function in 88 healthy blood donors: 48 smokers and 40 non-smokers. Two markers of endothelial dysfunction, plasminogen activator inhibitor-1 (PAI-1) and nitric oxide (NO) levels, were measured at baseline and after phlebotomy. It has been proposed that phlebotomy acutely activates the renin-angiotensin-aldosterone system, thereby activating endothelial activity and increasing PAI-1 and NO expression. At baseline there were no significant differences between smokers and non-smokers in terms of PAI-1 expression and NO levels. After phlebotomy, both PAI-1 and NO levels were significantly increased in both groups. The increase in PAI-1 was more pronounced in smokers and the increase in NO was more pronounced in non-smokers. These findings suggest that smoking causes endothelial dysfunction, even in healthy smokers, which may remain silent until a clinically evident disorder develops.