, Volume 98, Issue 1, pp 8-9
Date: 21 Jun 2013

Guest editorial: Pathophysiology and management of thrombocytopenia: possible clinical application of TPO receptor agonists

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Platelets are small, anucleated blood cells that exhibit a discoid shape when non-activated. Platelets play a crucial role in the formation of a pathologic thrombus as well as a normal hemostatic plug formation. Platelets express several adhesion receptors, such as GPIb–IX and GPIIb–IIIa, and circulate passively throughout the vascular tree covered by an intact monolayer of endothelial cells. In the initial step of hemostasis (and thrombus formation), platelets adhere to exposed subendothelial matrices at sites of vascular injury (or altered vascular surfaces). Following adhesion, they become activated, change shape, secrete granule contents, and aggregate to form a primary hemostatic plug and provide a catalytic surface to enhance blood coagulation. Platelets are released by megakaryocytes (MKs). Platelet counts are 130–320 × 103/μL in peripheral blood, and their average life span is 7–10 days. Red blood cell (RBC) counts in peripheral blood (4.4–5.6 × 106/μL) are approximately 20 tim ...