The role of cytokines in postmenopausal osteoporosis.

Postmenopausal osteoporosis is a silent systemic progressive disease characterised by a decrease in bone mass per unit volume. This condition compromises the physical strength of the skeleton and increases the susceptibility to fractures on minor trauma. The imbalance between bone formation and bone resorption is known to be responsible for postmenopausal bone loss. Estrogen deficiency contributes to bone loss by increasing the production of pro-inflammatory cytokines by bone marrow and bone cells. Clinical and molecular evidence indicates that estrogen-regulated cytokines exert regulatory effects on bone turnover implicating their role as being the primary mediators of the accelerated bone loss at menopause. The current perspective on the role and interaction of cytokines such as IL-1, IL-4, IL-6, IL-17, TNF, IFN-γ and TGF-β in bone loss linked with estrogen deficiency is reviewed. Current treatment options and emerging drug therapies in the management of postmenopausal osteoporosis are also evaluated.