Blood Coagulation System and Age

Abstract

Being dynamic and functional, blood coagulation system responds to the changing internal environment of the human body and the external factors. The transformation process of the blood coagulation system begins in fact from the first hours of life. There are intrinsic and extrinsic risk factors for thrombotic events, but aging is believed to be a universal and non-modifiable risk factor for thrombosis. The concentration of most coagulation factors in blood plasma increases with age. The fibrinolysis system and natural anticoagulants also change. Aging is believed to alter hemostasis, which generally reflects an enhanced procoagu-lant activity, compared with that of a younger age. Elements of the elevated procoagulant status may reflect current inflammatory processes. An increasing attention is now paid to the interaction of von Willebrand factor (vWF) and its specific regulator, ADAMTS-13 metalloprotease (a disintegrin and metalloprotease with thrombospondin type 1 motif, member 13), in various clinical models accom-panied by thrombosis development. This prothrombotic shift gets worse because of aging-related vWF level increase, especially if not compensated by a similar ADAMTS-13 level increase. On the other hand, vWF entering the bloodstream from endothelial cells circulates in a closed, inactive conformation. Physiologically, this conformation is necessary for its resistance to the proteolytic action of ADAMTS-13; therefore, vWF level has been suggested to be a questionable marker to determine the prothrombotic status.