The role of fibroblast growth factor 23 in chronic kidney disease-mineral and bone disorder.

Fibroblast Growth Factor 23 (FGF-23) is a bone-derived hormone involved in the regulation of phosphate homeostasis. FGF-23 levels are extremely elevated in Chronic Kidney Disease (CKD) and there is evidence supporting the role of this hormone in the pathogenesis of Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD). Furthermore, recent data associates FGF-23 with the pathogenesis of systemic complications of CKD-MBD. The increasing evidence that the consequences of abnormal mineral metabolism are not restricted to bone disease changed the approach to the pathophysiology and treatment of disturbed bone and mineral metabolism in CKD patients. FGF-23 has been proposed to be the initial adaptive response in early CKD to protect the organism from the adverse effects of phosphate retention. Increased levels of FGF-23 observed in CKD patients are associated with cardiovascular mortality risk and was shown to mediate direct, "off-target" toxicity to the heart. This report aims to review the relevant aspects of the physiology of FGF-23 in bone biology and mineral homeostasis and the role of FGF-23 in the pathophysiology of CKD-BMD and its clinical implications.