Osteogenic Growth Factors and Cytokines and Their Role in Bone Repair

Ontogenetic development is initiated at the time of fertilization and terminates with the differentiation, growth, and maturation of specialized tissues and organs. These developmental processes are characterized by molecular specialization that accompanies cellular differentiation and tissue morphogenesis. Most developmental processes terminate after birth or when animals reach sexual maturity, but some morphogenetic processes are reinitiated in response to injury in specific tissues. One such regenerative process is the repair of skeletal fractures and bone tissue after surgery, a process that recapitulates specific aspects of the initial developmental processes in the course of healing [58, 209]. Several aspects of the postnatal tissue environment of fracture healing, however, are unique and differ from what occurs in embryological and postnatal development.