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Therapeutic Effects of Anti‐FGF23 Antibodies in Hypophosphatemic Rickets/Osteomalacia
Author(s) -
Aono Yukiko,
Yamazaki Yuji,
Yasutake Junichi,
Kawata Takehisa,
Hasegawa Hisashi,
Urakawa Itaru,
Fujita Toshiro,
Wada Michihito,
Yamashita Takeyoshi,
Fukumoto Seiji,
Shimada Takashi
Publication year - 2009
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1359/jbmr.090509
Subject(s) - hypophosphatemia , rickets , osteomalacia , hypophosphatemic rickets , endocrinology , fibroblast growth factor 23 , medicine , vitamin d and neurology , biology , parathyroid hormone , calcium
X‐linked hypophosphatemia (XLH), characterized by renal phosphate wasting, is the most common cause of vitamin D‐resistant rickets. It has been postulated that some phosphaturic factor plays a causative role in XLH and its murine homolog, the Hyp mouse. Fibroblast growth factor 23 (FGF23) is a physiological phosphaturic factor; its circulatory level is known to be high in most patients with XLH and Hyp mice, suggesting its pathophysiological role in this disease. To test this hypothesis, we treated Hyp mice with anti‐FGF23 antibodies to inhibit endogenous FGF23 action. A single injection of the antibodies corrected the hypophosphatemia and inappropriately normal serum 1,25‐dihydroxyvitamin D. These effects were accompanied by increased expressions of type IIa sodium‐phosphate cotransporter and 25‐hydroxyvitamin‐D‐1α‐hydroxylase and a suppressed expression of 24‐hydroxylase in the kidney. Repeated injections during the growth period ameliorated the rachitic bone phenotypes typically observed in Hyp mice, such as impaired longitudinal elongation, defective mineralization, and abnormal cartilage development. Thus, these results indicate that excess actions of FGF23 underlie hypophosphatemic rickets in Hyp mice and suggest a novel therapeutic potential of the FGF23 antibodies for XLH.