Smoking cessation affects human platelet activation induced by collagen

It is firmly established that smoking is a risk factor of cardiovascular disease, stroke and peripheral vascular disease. Although smoking alters the hemostatic process, the influence of smoking on human platelet activation remains controversial. For patients undergoing surgery, cessation of smoking prior to the procedure is recommended as it increases the risk of postoperative morbidity or mortality. The presented study investigated the effects of smoking cessation on human platelet activation induced via collagen (n=19 patients). Blood samples were taken on four occasions: Before smoking cessation, and at 4, 8 and 12 weeks after smoking cessation. Platelet aggregation using citrated platelet-rich plasma (PRP) was monitored using a PA-200 aggregometer, which determined the size of platelet aggregates using laser scattering methods. A low dose of collagen (1 mu g/ml) accelerated platelet aggregation at 4 or 8 weeks after smoking cessation when compared with results before cessation. After 12 weeks, levels of platelet aggregation induced by collagen were almost equal to those recorded prior to smoking cessation. The secretion levels of collagen-induced platelet-derived growth factor (PDGF)-AB at 4 or 8 weeks after smoking cessation were significantly higher than those before smoking was stopped. Furthermore, smoking cessation markedly strengthened the collagen-induced phosphorylation of p38 mitogen-activated protein (MAP) kinase after 4 weeks. The results of the current study indicated that smoking cessation causes temporary short-term human platelet hyper-activation. The further suggest that the incidence of complications due to human platelet hyper-reactivity may be lowered by considering the period of smoking abstinence.