D-dimer physiology: Difference between revisions

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==Overview==
==Overview==
==Physiology==
[[Fibrin degradation product]]s (FDPs) are formed whenever [[fibrin]] is [[proteolysis|broken down]] by [[enzyme]]s. In fact, FDP are formed as a result of the sequential actions of the following three different enzymes: [[thrombin]], [[factor VIII]] and [[plasmin]].  Determining FDPs is not considered useful, as this does not indicate whether the fibrin is part of a blood clot (or being generated as part of [[inflammation]]).
D-dimers are unique in that they are the breakdown products of a fibrin mesh that has been stabilized by [[Factor XIII]]. This factor crosslinks the E-element to ''two'' D-elements. This is the final step in the generation of a thrombus.
[[Plasmin]] is a [[fibrinolysis|fibrinolytic]] enzyme that organizes clots and breaks down the fibrin mesh. It cannot, however, break down the bonds between one E and two D units. The protein fragment thus left over is a D-dimer.<ref name="pmid19008457‎">{{cite journal| author=Adam SS, Key NS, Greenberg CS| title=D-dimer antigen: current concepts and future prospects. | journal=Blood | year= 2009 | volume= 113 | issue= 13 | pages= 2878-87 | pmid=19008457‎ | doi=10.1182/blood-2008-06-165845 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=19008457  }} </ref>
Shown below is an image summarizing the formation of D-dimers and other [[fibrin degradation product]]s as a result of the sequential action of the three enzymes: [[thrombin]], [[factor VIII]] and [[plasmin]].
[[Image:D-dimer-formation.gif|500px|left|Formation of D-dimer]]
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==References==
==References==

Revision as of 13:37, 25 September 2013

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Physiology

Fibrin degradation products (FDPs) are formed whenever fibrin is broken down by enzymes. In fact, FDP are formed as a result of the sequential actions of the following three different enzymes: thrombin, factor VIII and plasmin. Determining FDPs is not considered useful, as this does not indicate whether the fibrin is part of a blood clot (or being generated as part of inflammation).

D-dimers are unique in that they are the breakdown products of a fibrin mesh that has been stabilized by Factor XIII. This factor crosslinks the E-element to two D-elements. This is the final step in the generation of a thrombus.

Plasmin is a fibrinolytic enzyme that organizes clots and breaks down the fibrin mesh. It cannot, however, break down the bonds between one E and two D units. The protein fragment thus left over is a D-dimer.[1]

Shown below is an image summarizing the formation of D-dimers and other fibrin degradation products as a result of the sequential action of the three enzymes: thrombin, factor VIII and plasmin.


Formation of D-dimer
Formation of D-dimer


References

  1. Adam SS, Key NS, Greenberg CS (2009). "D-dimer antigen: current concepts and future prospects". Blood. 113 (13): 2878–87. doi:10.1182/blood-2008-06-165845. PMID 19008457‎ Check |pmid= value (help).

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