Fast degrading elastomer enables rapid remodeling of a cell-free synthetic graft into a neo-artery

Host remodeling is important for the success of medical implants including vascular substitutes. Synthetic and tissue-engineered grafts have yet to show clinical effectiveness in arteries smaller than 5 mm. We designed cell-free biodegradable elastomeric grafts that degrade rapidly to yield neo-arteries nearly free of foreign materials 3 months after interposition grafting in rat abdominal aorta. This design focuses on enabling rapid host remodeling. Three months post-implantation, the neo-arteries resemble native arteries in the following aspects: regular, strong and synchronous pulsation, a confluent endothelium and contractile smooth muscle layers, co-expression of elastin, collagen and glycosaminoglycan, and tough and compliant mechanical properties. Therefore, future study employing large animal models more representative of human vascular regeneration is warranted before clinical translation. This cell-free approach represents a philosophical shift from the prevailing focus on cells in vascular tissue engineering, and may impact regenerative medicine in general.