Role of apoptotic processes in platelet biogenesis.

Platelets are anucleate cells that fragment from mature megakaryocytes and play an essential role in thrombosis and hemostasis. Platelets are among the first cell types to be recruited to an injured blood vessel, assisting in endothelial repair. Platelet hyperactivation contributes to the development of atherosclerosis, myocardial infarction, and ischemia of peripheral limbs. A fall in platelet counts, due to a variety of conditions, including disseminated intravascular coagulation, chemotherapy or genetic disorders, may lead, in most severe cases, to death from hemorrhage. This review focuses on the late stages of megakaryocyte differentiation and platelet fragmentation, including associated cytoskeletal changes, and on the importance of apoptotic events for these processes. Studies point to a unique biological system in which programmed cell death may be linked with biogenesis of new cells. Copyright 2004 S. Karger AG, Basel