New Strategies for the Prevention and Treatment of Systemic and Local Bone Loss; from Pathophysiology to Clinical Application.

Bone loss is the result of a negative unbalance between bone formation ad bone resorption. In the last years, the studies on the Wnt canonical pathway have highlighted its crucial role in bone balance through its influence on the activity and maturation of the osteoblast line and in the Receptor Activator of Nuclear Factor κ B (RANK) - RANK ligand (RANKL)/Osteoprotegerin (OPG) system. These mechanisms are involved not only in the pathological processes inducing not only systemic bone loss (i.e. Postmenopausal osteoporosis, glucocorticoid- induced osteoporosis, etc.), but also at a local level, as happens in Rheumatoid Arthritis (RA). Recently, several new drugs for the treatment of bone loss have been approved, while some others are still under development. The most promising new drugs in the treatment of osteoporosis include the antibody that neutralizes RANKL (denosumab, DMAb), monoclonal antibodies against sclerostin and parathyroid hormone-related protein analogue. Other new strategies for the prevention and treatment of bone loss include calcilytics, cathepsin K inhibitor or the combination or the sequential use of the current drugs. New insights concerning the treatment of the local bone loss in RA and in Complex Regional Pain Syndrome type I are also provided in this review.