Polyphosphate released from activated thrombocytes triggers the intrinsic pathway of coagulation in the absence of factor XII in chickens

Autor(es)

Prezoto, B. C. ; Abud, L. L. ; Borges, F. G. ; Carneiro, S. M. ; Aranha, T. E. D. O. ; Lewis, BS ; Flugelman, MY ; Halon, DA

• Tipo de documento: Artigo Científico
• Fonte: CORONARY ARTERY DISEASE: 2011 UPDATE: FROM PREVENTION TO INTERVENTION; v. N/A, p. 6-pg., 2011-01-01.

Resumo

Recent studies indicate that polyphosphates (polyP) released from activated platelets activate factor XII (FXII) in mammals. Birds have no FXII gene nor plasma FXII activity. We tested if the intrinsic pathway of coagulation can be activated by activated thrombocytes in chickens, using thromboelastometry. The clotting time of chicken thrombocyte-rich plasma samples was significantly decreased (48 +/- 7%, p < 0.0001) after stimulation with calcium ionophore A23187 (0.3 mu M). This effect was not prevented by the FXII inhibitor, corn trypsin inhibitor (p > 0.5), but was reverted by alkaline phosphatase and by the factor XI (FXI) inhibitor, aprotinin. Our results indicate that activated thrombocytes trigger the intrinsic pathway of coagulation in chickens. This activation does not depend on FXII, but depends on polyP and FXI-like substances. We propose that the study of avian clotting mechanism may help to understand the role of FXII and polyP both in hemostasis and thrombosis. (AU)

• Processo FAPESP: 09/54620-4 - Avaliação da atividade pró-coagulante do ácido ribonucléico (RNA) sobre a via intrínseca da coagulação sanguínea em mamíferos e aves
• Beneficiário: Benedito Carlos Prezoto
• Modalidade de apoio: Auxílio à Pesquisa - Regular