2008 Sol Sherry Distinguished Lecture in Thrombosis—Platelet Adhesion in Acute Arterial Thrombosis
Platelet adhesion is an essential function in response to vascular injury, through which single platelets bind to specific membrane receptors onto cellular and extracellular matrix constituents of the vessel wall and tissues initiating thrombus formation that arrests hemorrhage and permits wound healing. Pathological conditions that cause vascular alterations and blood flow disturbances may turn this defense process into a disease mechanism resulting in arterial occlusion, mostly in atherosclerotic vessels of the heart and brain. Besides their relevant role in hemostasis and thrombosis, platelet adhesive properties are central to a variety of pathophysiological processes that extend from inflammation to immune-mediated host defense and pathogenic mechanisms as well as cancer metastasis. All these activities depend on the ability of platelets to circulate in blood as sentinels of vascular integrity, adhere where alterations are detected, and signal the abnormality to other platelets and blood cells. In this respect, therefore, platelet adhesion to vascular wall structures, to one another (aggregation), or to other blood cells represents different aspects of the same fundamental biological process. Novel concepts and tools are being developed to advance our knowledge of the mechanisms through which platelets respond to vascular injury. Of particular interest are specific microparticles endowed with selective targeting properties conferred by recombinant adhesive domains that may be used for targeting areas of the vasculature with thrombogenic potential and for diagnostic purposes. Particles with such specific adhesive properties may also be used for the local delivery of anti-thrombotic drugs.