FGF23 and hyperphosphatemia: The importance of Pi homeostasis on long-term health is exemplified by KO or mutation of phosphaturic factors such as the osteocyte-derived hormone fibroblast growth factor 23 (FGF23) or its receptor binding cofactor Klotho, and this results in hyperphosphatemia, inflammation, and a premature-aging syndrome in mice (20, 21).