The role of growth factors in the repair of bone. Biology and clinical applications.

Abstract

•: Growth factors (bone morphogenetic protein, transforming growth factor-beta, fibroblast growth factor, platelet-derived growth factor, and insulin-like growth factor) are proteins secreted by cells that act on the appropriate target cell or cells to carry out a specific action. •: Because growth factors are expressed during different phases of fracture-healing, it has been thought that they may serve as potential therapeutic agents to enhance bone repair. •: The selection of an appropriate carrier or delivery system for a particular growth factor is essential in order to induce a specific biologic effect. •: There are a number of potential clinical applications for growth factors in the enhancement of bone repair, including acceleration of fracture-healing, treatment of established nonunions, enhancement of primary spinal fusion or treatment of established pseudarthrosis of the spine, and as one element of a comprehensive tissue-engineering strategy that could include gene therapy to treat large bone-loss problems. Growth factors are proteins that serve as signaling agents for cells. They function as part of a vast cellular communications network that influences such critical functions as cell division, matrix synthesis, and tissue differentiation. The results of experimental studies have established that growth factors play an important role in bone and cartilage formation, fracture-healing, and the repair of other musculoskeletal tissues. Recently, with the advent of recombinant proteins, there has been considerable interest in the use of growth factors as therapeutic agents in the treatment of skeletal injuries. As growth factors become available as therapeutic agents, it is essential that orthopaedic surgeons understand their biological characteristics and clinical potential. The purpose of this review is to define the mechanisms of action, functions, and potential clinical applications of a variety of growth factors that may be used clinically to treat problems associated with the repair of bone. Growth factors are proteins secreted …