[Clinical aspect of recent progress in phosphate metabolism. The functions of osteocytes]

Osteocytes form a network through processes and canaliculi throughout bone. Osteocytes have been reported to stimulate or inhibit bone formation and to inhibit bone resorption. As these functions have been estimated from the bone changes after osteocyte death, however, an inflammatory reaction in the microenvironment after necrosis has to be considered. The osteocyte network is thought to be a mechanosensor and mechanotransduction system due to its ideal anatomical feature. Further, osteocytes play an important role in phosphate metabolism, because osteocytes are important producers of FGF23, and FGF23 is upregulated in the osteocytes of Hyp mice and DMP1 knockout mice.