ROLE OF MORPHOGENETIC PROTEINS IN SKELETAL TISSUE ENGINEERING AND REGENERATION

Morphogenesis is the developmental cascade of pattern formation and bo dy plan establishment, culminating in the adult form. It has formed th e basis for the emerging discipline of tissue engineering, which uses principles of molecular developmental biology and morphogenesis gleane d through studies on inductive signals, responding stem cells, and the extracellular matrix to design and construct spare parts that restore function to the human body. Among the many organs in the body, bone h as considerable powers for regeneration and is a prototype model for t issue engineering. Implantation of demineralized bone matrix into subc utaneous sites results in local bone induction. This model mimics sequ ential limb morphogenesis and has permitted the isolation of bone morp hogens, such as bone morphogenetic proteins (BMPs), from demineralized adult bone matrix. BMPs initiate, promote, and maintain chondrogenesi s and osteogenesis, but are also involved in the morphogenesis of orga ns other than bone. The symbiosis of the mechanisms underlying bone in duction and differentiation is critical for tissue engineering and is governed by both biomechanics (physical forces) and context (microenvi ronment/extracellular matrix), which can be duplicated by biomimetic b iomaterials such as collagens, hydroxyapatite, proteoglycans, and cell adhesion glycoproteins, including fibronectins and laminin. Rules of tissue architecture elucidated in bone morphogenesis may provide insig hts into tissue engineering and be universally applicable for all orga ns/tissues, including bones and joints.