| Atherosclerosis (AS) is known as the main cause of inducing the development of cerebral thrombosis, myocardial infarction, and gangrene of the extremities, accompanied with a very high mortality. Percutaneous transluminal coronary angioplasty (PTCA) has been adopted as a measure for the treatment of coronary atherosclerotic diseases since last decade. Increased experience in practice and improvement of the equipments, facilities as well as the consummation of indications have led PTCA to be more and more expanded in clinical application. However, the high incidence of restenosis following 30-50% of initially successful procedures remains the major problem to be resolved. It's considered that migration and proliferation of vessel smooth muscle cell (SMC) play a predominant role in the development of restenosis. Growth factors and cytokines, such as PDGF, bFGF, E:GF, IGF-1, released from platelets, endothelial cells, activated monocytes and SMC, work together and stimulate SMC undergoing migration and proliferation. Although a lot of studies have been carried out, anyhow, the mechanism of SMC migration and proliferation in case of restenosis still remains not well understood.Data of recent investigations have suggested that plasminogen activators (PAs) system may play an important role in this process. Plasminogen activators, including tissue-type plasminogen activator(tPA) and urokinase-type plasminogen activator (uPA), are the major parts of fibrinolytic system. The principal function of these two plasminogen activators is to convert plasminogen to plasmin. Plasmin in turn degrades not only fibrin but also a broad range of extracellular matrix molecules. It also activates procollagenase to collagenase. Even though the effects of PAs on tumor and other cells have been studied and published, Clowes et al provided initial evidence for the expression of PAs in a balloon-injured rat carotid artery only...
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