Phosphate wasting and fibroblast growth factor-23

Area of Science:

• Endocrinology
• Nephrology
• Bone Metabolism

Background:

• Phosphate is essential for bone mineralization, muscle strength, and numerous biological functions.
• Bone senses phosphate levels and responds by secreting fibroblast growth factor-23 (FGF-23).

Purpose of the Study:

• To review the regulation of phosphate.
• To discuss recent advancements in understanding fibroblast growth factor-23 (FGF-23), a crucial hormone in phosphate regulation.

Main Methods:

• Literature review of studies on phosphate regulation.
• Analysis of research on FGF-23, including studies in patients with oncogenic osteomalacia and inherited phosphate-wasting rickets.
• Examination of data linking FGF-23 to cardiovascular disease in chronic kidney disease patients.

Main Results:

• FGF-23's primary role is to promote phosphaturia, with feedback loops involving FGF-23, 1,25-dihydroxyvitamin D3, and parathyroid hormone maintaining phosphate homeostasis.
• Studies have elucidated the pathophysiology of disorders involving FGF-23.
• Elevated FGF-23 is an independent risk factor for cardiovascular disease in chronic kidney disease.

Conclusions:

• Disorders of FGF-23 production, half-life, or response cause phosphate-wasting conditions, rickets, and oncogenic osteomalacia.
• Severely elevated FGF-23 levels in renal failure signify an independent risk for cardiovascular disease.
• The specific phosphate sensor that triggers FGF-23 production requires further identification.