Vascularization of engineered cartilage constructs in a mouse model

Tissue engineering of cartilage tissue offers a promising method for reconstructing ear, nose, larynx and trachea defects. However, a lack of sufficient nutrient supply to cartilage constructs limits this procedure. Only a few animal models exist to vascularize the seeded scaffolds. In this study, polycaprolactone (PCL)-based polyurethane scaffolds are seeded with 1 x 10(6) human cartilage cells and implanted in the right hind leg of a nude mouse using an arteriovenous flow-through vessel loop for angiogenesis for the first 3 weeks. Equally seeded scaffolds but without access to a vessel loop served as controls. After 3 weeks, a transposition of the vascularized scaffolds into the groin of the nude mouse was performed. Constructs (verum and controls) were explanted 1 and 6 weeks after transposition. Constructs with implanted vessels were well vascularized. The amount of cells increased in vascularized constructs compared to the controls but at the same time noticeably less extracellular matrix was produced. This mouse model provides critical answers to important questions concerning the vascularization of engineered tissue, which offers a viable option for repairing defects, especially when the desired amount of autologous cartilage or other tissues is not available and the nutritive situation at the implantation site is poor.