Mechanisms Of Blood Coagulation And Fibrynolisis In Xenarthra

CASANAVE E.B; POLINI NN

Pierre et Marie Curie et Sorbonne, France

Simposio; Simposio “Current Studies in Xenarthra”, en 8th International Congress of Vertebrate Morphology; 2007

Université de Paris VI (Simposio: Dr. Gerardo de Luliis (Canadá) y Dr. H. Gregory McDonald (USA)

MECHANISMS OF BLOOD COAGULATION AND FIBRINOLYSIS IN XENARTHRA CASANAVE, Emma Beatriz1* and POLINI, Nélida Nora2 1Cátedra de Fisiología Animal and 2Cátedra de Análisis Clínicos II, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan 670 (8000) Bahía Blanca, Argentina. 1 Researcher of Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET. E-mail: casanave@criba.edu.ar. Blood coagulation is an important process regulated by a large number of proteins that transform fibrinogen into fibrin. The blood coagulation network is probably present in all jawed vertebrates and possibly evolved before the divergence of tetrapods and teleosts. Among Xenarthra, nothing is known for sloths and anteaters, but we demonstrated that the armadillo has a haemostatic system similar to that of humans and other mammals. We identified the basic mammalian coagulation system, with two activation pathways, contact coagulation system and tissular factor coagulation system, and a common pathway, that leads to fibrin clot formation. We also demonstrated the presence of the coagulation factors and that of natural anticoagulation systems (antithrombin, protein C and protein S), with functional analogy to the human counterpart. Based on these facts, the armadillo has a haemostatic system similar to the one of the human being and other mammals. However, in this species the contact system pathway seems to play a greater role in the activation of the coagulation system than it does in humans, and the common pathway appears to limit the velocity of the system.  We also demonstrated the presence of a fibrinolytic system, similar to that of other mammals, through the measurement of the degradation products of fibrinogen and fibrin, with activity of alpha-2-antiplasmin. Essentially, the results suggest that armadillos have a hypercoagulable and hypofibrinolytic profile. Our findings constitute the only contribution on the physiology of the haemostatic and fibrinolytic system in Xenarthra. 1This study was supported by SGCyT-UNS, PGI 24/B122 and ANPCyT-BID PICTR 074/03.