Strontium ranelate in osteoporosis and beyond: identifying molecular targets in bone cell biology.

Osteoporosis is characterized by reduced bone mass and deterioration of bone microarchitecture, resulting in bone fragility and increased susceptibility to fractures. Current antiosteoporotic treatments depend on antiresorptive or anabolic drugs, but a novel modality of treatment appears to be mediated by strontium ranelate, which has been shown to act by opposing bone resorption and formation in vitro. This review article addresses the cellular and molecular mechanisms that have been implicated in the therapeutic strengthening of bone observed upon administration of strontium ranelate to osteoporotic patients. These mechanisms relate to specific pathways of calcium signaling, including complex networks involving nuclear factor of activated T cells (NFAT) and Wnt signaling.