Platelet aggregation is the clustering together of thrombocytes, which are small, cell-like structures made in the bone marrow that help prevent bleeding.
The clumping can occur in response to many different agents, including the nucleotide adenosine diphosphate (ADP), and the proteins thrombin and collagen.
Platelet aggregation is a crucial step in the process of clot formation, which stops bleeding. Once a primary layer of adhesive platelets have covered the exposed subendothelial matrix, subsequent adhesion will continue but in the form of aggregation, where platelets from flowing blood bind to adhered platelets at the wound site.
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The mechanism of platelet aggregation is mainly attributed to the integrin 11bβ3 (also know as GP11b/111a) receptor. The main ligand of integrin 11bβ3 is fibrinogen but the receptors also have affinity for multimeric Von Willebrand factor, Victronectin, fibronection and thrombospodin.
The mechanism of aggregation involves two integrin 11bβ3 receptor on different platelets that binds to the same fibrinogen molecules. The11bβ3 receptor has a low and high affinity state for binding fibrinogen. The high affinity state is achieved by inside-out signaling when platelets
are activated. The 11bβ3 receptor can also mediate outside-in signaling by binding fibrinogen. A platelet aggregation test can be performed to determine how well platelets are sticking together. The test measures this by using a platelet antagonist to initiate clumping in the patient’s blood sample.
The most common platelet antagonist are adenosine diphosphate, thrombin, and ristocetin. After the antagonist is added to the blood samples, a special machine called an aggregometer measures the turbidity or cloudiness, in the sample. The aggregometer records how quickly the platelets clump together by measuring the increased light and clarity in the fluid.
The aim of this work is to find out if vasoprine is platelet antagonist, whether it affects platelet adhesion and aggregation in these patients.
The study is very significant to serve as a tool for early detection of changes in platelet functions caused by vasoprine, before the appearance of clinical symptoms. This will equally serve as a guide who will help to carry out more specific investigations on the patients thereby preventing thrombocytopenia and sudden death.
Platelets Cells: PLATELET AGGREGATION