Strontium Ranelate

Strontium is a divalent cation that is closely chemically related to calcium. Strontium ranelate contains two atoms of stable strontium and an organic moiety (ranelic acid). Strontium increases pre-osteoblast replication, osteoblast differentiation, collagen type 1 synthesis and bone matrix mineralization (Fig. 18.1). In low doses strontium increases the density of the spongy bone. It reduces resorption and stimulates formation of bone, leading to a gain in bone mass and improved bone mechanical properties (Fig. 18.2). In other words, strontium uncouples the activity of the osteoclasts and osteoblasts, in favour of bone formation! Ongoing investigations of its activities have revealed other actions, whose overall effects include improvements in bone geometry, cortical bone thickness, trabecular bone morphology among other effects on bone quality, all of which enhance the strength of the bones. This has been confirmed in human trials with increased bone-specific alkaline phosphatase (a marker of bone formation) and decreased C-terminal peptide (a marker of bone resorption). The increment in bone density is comparable to that achieved by fluoride: up to 20%.