Haematologica Reports 2005; 1(issue 9): 56-58
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The protein C system in inflammation and cancer: a
critical role for thrombomodulin
Spronk H , Ten Cate H
Laboratory for Clinical, Thrombosis and Haemostasis, dept. of
Internal Medicine and Cardiovascular Research
Institute Maastricht, University Hospital Maastricht, Maastricht,
The Netherlands
The protein C system comprises the cellular receptors
thrombomodulin (TM) and endothelial protein C receptor (EPCR), and
the soluble proteins C and S. Thrombin binds to TM and this complex
jointly with protein C bound to EPCR generates activated protein C
(APC). One of the main functions of APC in blood coagulation is to
regulate the rate of thrombin generation, in complex with protein
S, by inhibiting factors Va and VIIIa through limited proteolytic
cleavage.1 Defects in one of the factor V cleavage sites
for APC, e.g. the factor V Leiden variant, renders this protein
partially resistant to cleavage by APC and the clinical result is
an increased risk of venous thrombosis. Similarly, heterozygous
deficiencies in PC or PS cause a marked increase in the risk of
venous thrombosis. Complete absence of these proteins is hardly
compatible with life due to massive disseminated intravascular
coagulation. [>Read full article in
PDF]
