The robust repair of large wounds and tissue defects relies on blood flow. This vascularization is the major challenge faced by tissue engineering on the path to forming thick, implantable tissue constructs. Without this vasculature, oxygen and nutrients cannot reach the cells located far from host blood vessels. To make viable constructs, tissue engineering takes advantage of the mechanical properties of synthetic materials, while combining them with extracellular matrix proteins to create a natural environment for the tissue- specific cells. Tropoelastin, the precursor of the elastin, is the extracellular matrix protein responsible for elasticity in diverse tissues, including robust blood vessels.
Tropoelastin contributes two distinct functions: a physical role in elasticity and an emerging substantial role in the biology of repairing tissue.
The emerging model from a range of our other collaborative in vivo studies is that tropoelastin encodes direct biological effects and has the versatility to promote tissue repair. We found that tropoelastin substantially improves healing by halving the time to repair full-thickness wounds in mice and pigs; tropoelastin elicits this response with early stage neo-angiogenesis, recruitment of mesenchymal stem cells and fibroblasts with enhanced repair in two weeks consistently in these small and large animals. We discovered that tropoelastin tightly controls vascular smooth muscle cell proliferation in neovessels following mouse implantation and sheep carotid interposition surgery. This potency is marked by the concerted appearance of blood vessels, neodermis and other tissues that work together to accelerate skin repair.