Cardiology

Detecting problems of the anti-bleeding system in 60 minutes

Various diseases can cause hemorrhages or thromboses, sometimes fatal, resulting in particular from complications during surgery. This may take the form of a dysfunction of the platelets (hemostasis), the blood cells that ...

Medical research

A better understanding of the von Willebrand Factor's A2 domain

Under normal, healthy circulatory conditions, the von Willebrand Factor (vWF) keeps to itself. The large and mysterious multimeric glycoprotein moves through the blood, balled up tightly, its reaction sites unexposed. But ...

Cardiology

Experimental antiplatelet compound for acute stroke shows promise

An experimental antiplatelet compound inhibited clot formation without increasing bleeding, a common and potentially dangerous side effect of current anticlotting therapies, according to new phase I research in Arteriosclerosis, ...

Diseases, Conditions, Syndromes

Aspirin to fight an expensive global killer infection

Research led by the Centenary Institute in Sydney has found a brand new target for treating drug-resistant tuberculosis; our scientists have uncovered that the tuberculosis bacterium hijacks platelets from the body's blood ...

Medical research

Researchers uncover aspirin's effects on platelet rich plasma

A collaborative study led by researchers at Baylor College of Medicine explores the effects of aspirin on a new biologic therapy, platelet rich plasma (PRP). This is the first study of its kind to examine the defects of aspirin ...

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Platelet

Platelets, or thrombocytes (from Greek θρόμβος, "clot" and κύτος, "cell"), are small, irregularly shaped clear cell fragments (i.e. cells that do not have a nucleus containing DNA), 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes.  The average lifespan of a platelet is normally just 5 to 9 days. Platelets are a natural source of growth factors. They circulate in the blood of mammals and are involved in hemostasis, leading to the formation of blood clots.

If the number of platelets is too low, excessive bleeding can occur. However, if the number of platelets is too high, blood clots can form (thrombosis), which may obstruct blood vessels and result in such events as a stroke, myocardial infarction, pulmonary embolism or the blockage of blood vessels to other parts of the body, such as the extremities of the arms or legs.  An abnormality or disease of the platelets is called a thrombocytopathy, which could be either a low number of platelets (thrombocytopenia), a decrease in function of platelets (thrombasthenia), or an increase in the number of platelets (thrombocytosis). There are disorders that reduce the number of platelets, such as heparin-induced thrombocytopenia (HIT) or thrombotic thrombocytopenic purpura (TTP) that typically cause thromboses, or clots, instead of bleeding.

Platelets release a multitude of growth factors including Platelet-derived growth factor (PDGF), a potent chemotactic agent, and TGF beta, which stimulates the deposition of extracellular matrix.  Both of these growth factors have been shown to play a significant role in the repair and regeneration of connective tissues.  Other healing-associated growth factors produced by platelets include basic fibroblast growth factor, insulin-like growth factor 1, platelet-derived epidermal growth factor, and vascular endothelial growth factor.  Local application of these factors in increased concentrations through Platelet-rich plasma (PRP) has been used as an adjunct to wound healing for several decades.

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