Thrombin and Vascular Development

Abstract

Formation of the vasculature is an essential step in embryogenesis. It was observed decades ago that the vasculature and the intravascular blood compartment, which uses the former as a means of transportation, develop in a close spatial and temporal relationship. In this review, we discuss the role of the blood coagulation system as a tool to coordinate angiogenesis. Several mouse models lacking coagulation factors result in impaired thrombin generation and display a phenotype of disturbed cardiovascular development. Similar phenotypes are observed in mouse models of impaired thrombin binding to its cellular receptor, protease-activated receptor-1, or of disrupted signaling via G proteins. Most interestingly, the available data provide evidence that thrombin signaling in vascular development cannot be explained by a model based only on the classic extrinsic and intrinsic coagulation pathways. Because angiogenesis in adults follows the same signaling patterns as angiogenesis in embryos, it is important to learn about these pathways, hoping that they may serve as therapeutic targets in cardiovascular disease.