Bone Remodeling

Skeletal buildup and maintenance is ensured by modeling and remodeling processes. Bone modeling works mainly during organism growth and is characterized by bone formation prevailing on resorption: The two processes are carried out simultaneously but not at the same location. In the bone remodeling, occurring throughout the life, osteoclasts remove the old bone, and osteoblasts replace it with the equal amount at the same site. The control of bone modeling and remodeling is very complex and involves both mechanical forces and biological factors. These include either circulating hormones, such as growth hormone, estrogen, androgen, PTH, and locally produced factors, such as Wnt signaling molecules and bone morphogenetic proteins. This chapter describes the sequential phases of bone remodeling as well as the last knowledge about its regulation by mechanical loading, circulating, and locally produced molecules. © Springer-Verlag Italia 2014, Corrected Printing 2014