PECAM1 and isolated hemihyperplasia: In this strain, although these CD31+ myofibrocytes are recruited to the vessel wall post-injury, no IH develops, and adoptive transfer of CD34+ cells from these mice to injured WT mice inhibits the development of IH, a phenotype that is due to the expression of the hTFPI transgene, as an inhibitory anti-hTFPI antibody reverses the protection offered by the hTFPI (8).