Diabetes and the platelet: toward new therapeutic paradigms for diabetic atherothrombosis.

Atherothrombosis--defined as atherosclerotic lesion disruption with superimposed thrombus formation--is a leading cause of death in patients with diabetes mellitus. Platelets play a pivotal role in atherothrombosis and platelets of diabetic patients are hyperreactive. Numerous studies have investigated the usefulness of antiplatelet therapy for primary and secondary prevention of atherothrombotic events in diabetic patients. However, there are limited evidences that aspirin may be effective in the reduction of atherothrombotic complication in this population. Additionally, dual antiplatelet therapy with aspirin and clopidogrel has been suggested to be harmful. In contrast, the role of antiplatelet therapy in secondary prevention after ischemic cardiac events is well established in diabetes. Glycoprotein IIb/IIIa receptor antagonists can reduce mortality in diabetic patients committed to undergo percutaneous coronary intervention (PCI). Upregulation of P2Y(12) signalling occurs in hyperglycemia, and the relevance of platelet P2Y(12) receptor inhibition with prasugrel in reducing adverse events following PCI has been recently suggested. Besides platelet activation, several other mechanisms may be involved in the pathophysiology of diabetic atherothrombosis. Tissue factor (TF)-bearing procoagulant microparticles (MPs) are a heterogeneous population of membrane-coated vesicles released by several cell lines upon activation or apoptosis. There is converging evidence that MPs and MP-associated TF activity are upregulated in patients with diabetes mellitus and can participate actively in promoting atherothrombotic complications. In this context, drugs that may reduce the release of microparticles and/or their thrombogenic capacity has the potential to improve upon current antiplatelet therapy, possibly resulting in lower adverse events rates in diabetic individuals.