Growth factors, bone metabolism, and metabolic bone diseases

Skeletal cells synthesize growth factors with important effects on the replication and differentiated function of cells of the osteoblast and osteoclast lineage. Growth factors can be regulated at the level of synthesis, activation, receptor binding, and binding proteins. Changes in growth factor levels or activity may play a role in the pathogenesis of metabolic bone disorders. Growth factors could be used topically for the treatment of fractures. Their systemic use for the treatment of metabolic bone disorders has been postulated, and it may be practical for short periods of time. Growth factors also can be used indirectly in the treatment of osteoporosis by developing agents that modify their synthesis or activity in the bone microenvironment.