[Repair and formation of cartilage and bone: are they possible?].

Osteoporosis and osteoarthritis cause serious problems to the mobility, and therefore to the quality of life, of aged people. This is due to the fact that both diseases result from irreversible loss of quality or function of the tissues; i.e., bone and articular cartilage. Recent progress in molecular biology and developmental biology, however, have contributed a great deal to our understanding of the mechanisms regulating growth and differentiation of osteoblasts and chondrocytes, the cells responsible for producing bone and cartilage, respectively. In vivo studies using animals including humans also shed light on the mechanism underlying these biological events as well as diseases and provide ideas for possible interventions for treating these disease states. This review will deal with these new developments in the field and discuss possibility to develop new potential strategies for treating patients with those disorders.