Inoculation of an established endothelial cell line from transgenic mouse hemangiomas (Py-4-1) into histocompatible mice induced vascular tumor formation at the site of infection with 100% frequency. Histological and hematological studies revealed that the mice developed hemangiomas with hematological changes similar to those found in the Kasabach-Merritt syndrome in humans, including hemolytic anemia and thrombocytopenic purpura. Modifications in the red blood cell count, hemoglobin concentration, hematocrit, and platelet count were directly correlated with the size of the hemangioma. Thus transgenic endothelial cell injection into histocompatible mice provides an in vivo model system to study the pathobiology of hemangiomas as well as the investigation of angiogenesis inhibitors
