We define regenerative engineering as a convergence of advanced materials science, stem cell science, physics, developmental biology, and clinical translation. Stem cells play an important role. Work in the area of musculoskeletal tissue regeneration has focused on a number of paradigms. Polymer and polymer-ceramic systems can be utilized for the regeneration of bone. Direct induction can be controlled through material characteristics. Through the use of inducerons, small molecules fostering induction, the design of regeneration-inducing materials can be realized. We believe the medicinal use of stem cells will be of critical importance in the design of next generation systems answering grand challenges to musculoskeletal regeneration.

We have evaluated in vivo a novel, polymer-based, matrix for tissue engineering of bone. A segmental defect of 15 mm was created in the ulna of New Zealand white rabbits to determine the regenerative properties of a porous polylactide-co-glycolide matrix alone and in combination with autogenous marrow and/or the osteoinductive protein, BMP-7. In this study four implant groups were used: 1) matrix alone; 2) matrix with autogenous marrow; 3) matrix with 20 μg of BMP-7; and 4) matrix with 20 μg of BMP-7 and autogenous marrow.

The results showed that the degree of bone formation was dependent on the properties of the graft material. The osteoconductive sintered matrix structure showed significant formation of bone at the implant-bone interface. The addition of autogenous marrow increased the penetration of new bone further into the central area of the matrix and also increased the degree of revascularisation. The osteoinductive growth factor BMP-7 induced penetration of new bone throughout the entire structure of the implant. The most effective treatment was with the combination of marrow cells and osteoinductive BMP-7.