title: Stem cell- and scaffold-based tissue engineering approaches to osteochondral  regenerative medicine.
abstract: In osteochondral tissue engineering, cell recruitment, proliferation, differentiation, and patterning are critical for forming biologically and structurally viable constructs for repair of damaged or diseased tissue. However, since constructs prepared ex vivo lack the multitude of cues present in the in vivo microenvironment, cells often need to be supplied with external biological and physical stimuli to coax them toward targeted tissue functions. To determine which stimuli to present to cells, bioengineering strategies can benefit significantly from endogenous examples of skeletogenesis. As an example of developmental skeletogenesis, the developing limb bud serves as an excellent model system in which to study how osteochondral structures form from undifferentiated precursor cells. Alongside skeletal formation during embryogenesis, bone also possesses innate regenerative capacity, displaying remarkable ability to heal after damage. Bone fracture healing shares many features with bone development, driving the hypothesis that the regenerative process generally recapitulates development. Similarities and differences between the two modes of bone formation may offer insight into the special requirements for healing damaged or diseased bone. Thus, endogenous fracture healing, as an example of regenerative skeletogenesis, may also inform bioengineering strategies. In this review, we summarize the key cellular events involving stem and progenitor cells in developmental and regenerative skeletogenesis, and discuss in parallel the corresponding cell- and scaffold-based strategies that tissue engineers employ to recapitulate these events in vitro.
authors.affiliation: Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA 02155, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Sundelacruz
authors.forename: David L
authors.initials: DL
authors.lastname: Kaplan
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D019485:Bone Morphogenetic Proteins / Q000502:physiology*; D001861:Bone Regeneration; D001842:Bone and Bones / Q000502:physiology; D002454:Cell Differentiation; D049109:Cell Proliferation; D020219:Chondrogenesis; D006801:Humans; D044968:Regenerative Medicine; D013234:Stem Cells / Q000502:physiology*; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D019485:Bone Morphogenetic Proteins