Chapter 28 - Molecular Basis of Bone Diseases

Abstract

Bone is not an inert structure but a living and metabolic active tissue, which undergoes continuous remodeling throughout life, to allow bone architecture to respond to mechanical stress, consisting in bone tissue renewal to replace old bone tissue with new bone matrix. The equilibrium between osteoblasts and osteoclasts activity is the key of bone homeostasis, and any perturbation of this balance leads to the development of skeletal pathological condition characterized by decrease or an excess of bone mass. Bone is a living tissue undergoing a continuous remodeling, in order to respond to a variety of different stimuli, ranging from mechanical loading, to hormonal factors and calcium homeostasis. For this reason, bone is a metabolically active tissue, and bone metabolism is a complex series of event under the control of different genetic, hormonal, and biochemical factors. This chapter will describe the molecular basis of the main bone disease characterized by or an excess of bone mass, as well as metabolic bone disease. In addition, due to its structure, bone is usually protected from infections, but it can undergo infection. Moreover, bone can also be affected by primary tumor or metastatic invasion. This chapter also provides the most recent insight concerning bone infections and bone tumors and metastases.