Tissue factor-thrombin-PAR-1 pathway: a novel link between bone marrow and blood vessel.

Transplant arteriopathy (TA) is an important limitation to graft survival following solid organ transplantation.1 TA is a result of immune-mediated mechanisms and results in intimal hyperplasia (IH) and vascular occlusion. Our understanding of the mechanism for this process is expanding to include an important role for host derived-circulating cells, including cells that adopt a smooth muscle cell phenotype within the intima of vessels.2 In this issue of Arteriosclerosis, Thrombosis, and Vascular Biology, Chen and colleagues3 add to this understanding of TA in a new and unexpected way that suggests that the tissue factor (TF)-thrombin–PAR-1 pathway may provide an important link between the bone marrow and blood vessels.