Platelets are small anuclear cells that play a central role in haemostasis. Platelets become activated in response to various stimuli triggering release of their granular contents into the surrounding milieu. One of these types of granules, termed dense granules, have been found to contain polyphosphate (polyP) in addition to other inorganic biomolecules, such as serotonin, ADP, ATP, PPi. Individuals deficient in dense granules exhibit bleeding tendencies, emphasizing their importance in haemostasis. Platelet polyP is of a relatively defined size, approximately 60–100 phosphate monomers in length. These linear polymers act at various points in the coagulation and fibrinolytic systems thereby modulating the haemostatic response. Due to its highly anionic nature, polyP lends itself to being a natural activator of the contact system. The contact system functions in multiple pathways including coagulation, fibrinolysis, inflammation and complement. Activation of the contact system accelerates thrombin generation, the terminal enzyme in the coagulation cascade. PolyP also modulates factors further downstream in the coagulation cascade to augment thrombin generation. The net effect is increased fibrin formation and platelet activation resulting in faster clot formation. PolyP is incorporated into the forming clot thereby modifying the structure of the resulting fibrin network and its susceptibility to degradation by certain plasminogen activators. In conclusion, release of platelet polyP at the site of injury may facilitate clot formation and augment clot stability thereby promoting wound healing.
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February 2016
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Cover Image
Scanning electron micrograph of a cell from the endosperm of a barley grain. The cell is tightly packed with large, disk-shaped (A-type) and much smaller, almost spherical (B-type) starch granules. The smooth areas in this image are the surface of the cell walls of neighbouring endosperm cells. For further details see pp. 157-163. Image kindly provided by Elaine Barclay and Vasilios Andriotis (John Innes Centre, Norwich). - PDF Icon PDF LinkTable of Contents
Review Article|
February 09 2016
Polyphosphate as a haemostatic modulator
Nicola J. Mutch
Nicola J. Mutch
1
*Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, U.K.
1email n.j.mutch@abdn.ac.uk.
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Publisher: Portland Press Ltd
Received:
November 13 2015
Online ISSN: 1470-8752
Print ISSN: 0300-5127
© 2016 Authors; published by Portland Press Limited
2016
Biochem Soc Trans (2016) 44 (1): 18–24.
Article history
Received:
November 13 2015
Citation
Nicola J. Mutch; Polyphosphate as a haemostatic modulator. Biochem Soc Trans 15 February 2016; 44 (1): 18–24. doi: https://doi.org/10.1042/BST20150207
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