Functional Tissue Engineering of Bone: Signals and Scaffolds

T issue engineering is the science of design and manufacture of tissues including bones and other musculoskeletal tissues. The three key ingredients for both tissue engineering and morphogenesis are signals for morphogenesis, responding stem cells and the scaffolding. Regeneration of musculoskeletal tissues recapitulates embryonic development and morphogenesis. Morphogenesis is the developmental cascade of pattern formation, body plan establishment leading to adult form and function. Therefore, signals involved in morphogenesis will be useful for tissue engineering of bones. BMPs have pleiotropic roles in initial pattern formation, cell differentiation and maintenance of bone and articular cartilage. The regenerative potency of bone is due to bone morphogenetic proteins (BMPs) in the bone matrix. BMPs act via BMP receptors and Smads 1, 5 and 8 to initiate lineage of cartilage and bone. The homeostasis of tissue engineered bone and cartilage is dependent on the maintenance of extracellular matrix and biomechanics. The use of BMPs by gene therapy and isolation of stem cells in a biomimetic scaffold of extracellular matrix will lead to functional bone tissue. In conclusion, these are exciting times in functional tissue engineering of bone using signals, scaffolds and stem cells.