Normal platelet function

Abstract

Platelets play an important role in the vessel. Following their formation from megakaryocytes, platelets exist in circulation for 5–7 days and primarily function as regulators of hemostasis and thrombosis. Following vascular insult or injury, platelets become activated in the blood resulting in adhesion to the exposed extracellular matrix underlying the endothelium, formation of a platelet plug, and finally formation and consolidation of a thrombus consisting of both a core and shell. In pathological conditions, platelets are essential for formation of occlusive thrombus formation and as a result are the primary target for prevention of arterial thrombus formation. In addition to regulation of hemostasis in the vessel, platelets have also been shown to play an important role in innate immunity as well as regulation of tumor growth and extravasations in the vessel. These primary functions of the platelet represent its normal function and versatility in circulation.

Early decrease in blood platelet count is associated with poor prognosis in COVID-19 patients—indications for predictive, preventive, and personalized medical approach

“…As well known, the platelet count shows the production and decay of thrombocytes, which also reflects the relation of the consumption and generation of platelets in the body to some degree [26]. Therefore, platelet count can act as a sensitive indicator of illness severity and shows early changes in conditions, indirectly reflecting the body's ability to resist the disease.…”

Blood platelet research in autism spectrum disorders: In search of biomarkers

“…Using a light‐transmission aggregometer, platelets are activated by adding an agonist such as ADP, collagen, thrombin, epinephrine or thromboxane A2 analog (U46619) that boosts platelet‐platelet interactions and the release of their granules to achieve a full activation response (Figure ). Table presents the few studies that have performed platelet activation studies for ASD.…”

Proteolytic processing of platelet receptors

“…This process requires the engagement of platelet receptors that mediate both the rolling and adhesion of platelets, as well as the intraplatelet signalling leading to platelet degranulation, Ca 2+ flux, release of secondary agonists such as adenosine diphosphate (ADP) and thromboxanes, exposure of phosphatidylserine and upregulation of fibrinogen‐binding capacity by the platelet‐specific integrin αIIbβ3. This process has been described extensively in a number of recent reviews …”

“…This process has been described extensively in a number of recent reviews. [8][9][10][11] The process of primary hemostasis is governed by the plateletspecific adhesion/signalling proteins glycoprotein (GP) Ib-IX-V and GPVI which predominantly bind von Willebrand factor (VWF) and collagen, respectively. 12 Both receptors can engage with other ligands, however, engagement of these receptors by VWF and collagen coordinate the platelet response to exposed subendothelial matrix across a range of vascular flow rates.…”