Annales de Biologie Clinique

Published by John Libbey Eurotext
Print ISSN: 0003-3898
Protein C is a potent inhibitor of blood coagulation, and, in addition, appears to be a profibrinolytic agent. In a first step, protein C must be converted to a serine protease. This activation is catalyzed by a complex formed between thrombin and thrombomodulin, an endothelial cell surface protein. Activated protein C exhibits its anticoagulant activity through the proteolytic inactivation of two blood coagulation cofactors, factors Va and VIIIa. This reaction requires phospholipids, originating from platelets or endothelial cells, and a cofactor protein, protein S. Protein S enhances the binding of activated protein C to phospholipids. In addition, activated protein C stimulates fibrinolysis, through the inactivation of the tissue plasminogen activator (tPA) inhibitor. An isolated constitutional, quantitative or qualitative, protein C or protein S deficiency increases the risk of thrombosis, the clinical features are different in the rare cases of homozygous protein C deficiency (neonatal purpura fulminans) or in the heterozygous patients (recurrent venous thrombosis in young adults). Acquired deficiency in protein C and S had been observed in liver disease, during vitamin K antagonists or L-Asparaginase treatment, and in disseminated intravascular coagulation.
Top-cited authors
Gregory J Tsongalis
  • Geisel School of Medicine at Dartmouth
Anne Vassault
  • Hôpital Universitaire Necker
Dominique Bonnefont-Rousselot
  • Paris Descartes, CPSC
Patrice Thérond
  • Paris Descartes, CPSC
Guillaume Lefèvre
  • Hôpital Tenon (Hôpitaux Universitaires Est Parisien)