Figure 2.

(A) Masson's trichrome stain shows the remodeled ECM scaffold material. The neo-tissue is characterized by a highly aligned and organized accumulation of spindle cells and collagen fibers oriented along the length of the pulmonary artery. The luminal surface (top) is lined by endothelial cells and there is a vascular adventitia on the abluminal surface. Sections of a nerve fiber can also be seen at the lower left corner of the image. (B) Image showing positive immunolabeling for CD31+ endothelial cells along the luminal surface of the remodeled graft material. (C) Masson's trichrome stain shows the anastomotic site between the native pulmonary artery and the graft material. The oval unstained space at the left represents the site of suture placement. The graft material (to the right of the suture) is characterized by an organized, aligned accumulation of collagen fibers and spindle-shaped cells. The bottom portion of the picture shows the vascular adventitia with a section of nerve fiber.