Background The clinical benefit of coronary-artery stenting performed in conjunction with coronary angioplasty is limited by the risk of thrombotic occlusion of the stent as well as hemorrhagic and vascular complications of intensive anticoagulation. We compared antiplatelet therapy with conventional anticoagulant therapy with respect to clinical outcomes 30 days after coronary-artery stenting. Methods After successful placement of Palmaz–Schatz coronary-artery stents, 257 patients were randomly assigned to receive antiplatelet therapy (ticlopidine plus aspirin) and 260 to receive anticoagulant therapy (intravenous heparin, phenprocoumon, and aspirin). The primary cardiac end point was a composite measure reflecting death from cardiac causes or the occurrence of myocardial infarction, aortocoronary bypass surgery, or repeated angioplasty. The primary noncardiac end point comprised death from noncardiac causes, cerebrovascular accident, severe hemorrhage, and peripheral vascular events. Results Of the pati...

A Randomized Comparison of Antiplatelet and Anticoagulant Therapy After the Placement of Coronary-Artery Stents.

Article de synthese sur les roles des integrines β1 (proteines VLA) comme recepteurs dans l'adherence des leucocytes a la matrice extracellulaire et comme recepteurs dans l'adherence cellule a cellule

VLA proteins in the integrin family : structures, functions and their role on leukocytes

Proteinase-activated receptors are a recently described, novel family of seven-transmembrane G-protein-coupled receptors. Rather then being stimulated through ligand receptor occupancy, activation is initiated by cleavage of the N terminus of the receptor by a serine protease resulting in the generation of a new tethered ligand that interacts with the receptor within extracellular loop-2. To date, four proteinase-activated receptors (PARs) have been identified, with distinct N-terminal cleavage sites and tethered ligand pharmacology. In addition to the progress in the generation of PAR-1 antagonists, we describe the role of thrombin in such processes as wound healing and the evidence implicating PAR-1 in vascular disorders and cancer. We also identify advances in the understanding of PAR-1-mediated intracellular signaling and receptor desensitization. The cellular functions, signaling events, and desensitization processes involved in PAR-2 activation are also assessed. However, other major aspects of PAR-2 are highlighted, in particular the ability of several serine protease enzymes, in addition to trypsin, to function as activators of PAR-2. The likely physiological and pathophysiological roles for PAR-2 in skin, intestine, blood vessels, and the peripheral nervous system are considered in the context of PAR-2 activation by multiple serine proteases. The recent discovery of PAR-3 and PAR-4 as additional thrombin-sensitive PARs further highlights the complexity in assessing the effects of thrombin in several different systems, an issue that remains to be fully addressed. These discoveries have also highlighted possible PAR–PAR interactions at both functional and molecular levels. The future identification of other PARs and their modes of activation are an important future direction for this expanding field of study.

Proteinase-Activated Receptors

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1538-7836.2005.01377.x

Protease-activated receptors in hemostasis, thrombosis and vascular biology.

Proteinase-activated receptors

FIBRINOLYTIC therapy is a major advance in the treatment of occlusive vascular disease. Problems remain, however, including resistance to fibrinolytic therapy, delays in reperfusion, reocclusion after successful thrombolysis, and serious hemorrhage.1 2 3 Increasing evidence indicates that platelets have an important role in both delaying reperfusion and mediating reocclusion. In addition, preliminary data suggest that some thrombi resist lysis because they are rich in platelets and that platelet dysfunction contributes to the hemorrhagic diathesis associated with thrombolytic therapy. It is worthwhile, therefore, to review the complex interrelations between platelets and fibrinolysis, with emphasis on the therapeutic potential (and risks) of combining thrombolytic . . .

Platelets and thrombolytic therapy.

Collagen-platelet interactions: evidence for a direct interaction of collagen with platelet GPIa/IIa and an indirect interaction with platelet GPIIb/IIIa mediated by adhesive proteins

Platelet vitronectin receptor expression differentiates Iraqi-Jewish from Arab patients with Glanzmann thrombasthenia in Israel

Platelets contribute significantly to vaso-occlusive thrombosis, one of the major causes death and disease throughout the world. Consequently, inhibiting platelet function is a potentially important therapeutic goal. Increasing evidence indicates the value of aspirin, a relatively weak anti­ platelet agent in the prophylaxis and treatment of vascular disease, and of ticlopidine, a somewhat more potent anti platelet agent that may be somewhat more effective clinically. Recent advances in our understanding of platelet physiology provide crucial information for the rational design of newer agents that can neutralize thrombin and block the platelet recep­ tor most important in platelet aggregation (GPIIb/IIIa). Several such agents, which are much more potent than aspirin in vitro and in animal models of thrombosis, are now in human clinical trials.

Antiplatelet agents in the prevention and therapy of thrombosis.

Platelet fibrinogen and vitronectin in Glanzmann thrombasthenia: evidence consistent with specific roles for glycoprotein IIb/IIIA and alpha v beta 3 integrins in platelet protein trafficking [see comments]

Barry S. Coller

Papers

Platelets and thrombolytic therapy.

Collagen-platelet interactions: evidence for a direct interaction of collagen with platelet GPIa/IIa and an indirect interaction with platelet GPIIb/IIIa mediated by adhesive proteins

Platelet vitronectin receptor expression differentiates Iraqi-Jewish from Arab patients with Glanzmann thrombasthenia in Israel

Antiplatelet agents in the prevention and therapy of thrombosis.

Platelet fibrinogen and vitronectin in Glanzmann thrombasthenia: evidence consistent with specific roles for glycoprotein IIb/IIIA and alpha v beta 3 integrins in platelet protein trafficking [see comments]