Total parathyroidectomy reduces elevated circulating fibroblast growth factor 23 in advanced secondary hyperparathyroidism.
BACKGROUND
Secondary hyperparathyroidism is a common complication in patients with stage 5 chronic kidney disease (CKD), accelerated by hyperphosphatemia. Fibroblast growth factor 23 (FGF-23), a phosphorus-regulating protein, has key roles in several phosphate-wasting disorders. The aim of this study is to examine the association of advanced secondary hyperparathyroidism with circulating FGF-23 levels.


METHODS
Fifteen patients with marked secondary hyperparathyroidism (parathyroid hormone [PTH], 990 +/- 118 pg/mL [ng/L]) were enrolled. All underwent parathyroidectomy with forearm autotransplantation (PTX), and their FGF-23 levels were measured before and after PTX (days 1, 3, 7, and 10) by means of sandwich enzyme-linked immunosorbent assay.


RESULTS
Preoperative FGF-23 levels correlated positively with phosphorus (P < 0.05), calcium-phosphorus product (Ca x P; P < 0.0005), and PTH values (P < 0.05). Serum FGF-23 levels decreased time dependently after PTX (P < 0.0005). Both serum phosphorus and Ca x P values decreased similarly after PTX ( P = 0.0001). Furthermore, FGF-23 levels days 1 and 3 correlated linearly with serum phosphorus (P < 0.05; P < 0.005, respectively) and Ca x P values (P < 0.01; P < 0.0001, respectively).


CONCLUSIONS
FGF-23 levels correlate positively with serum phosphorus, Ca x P, and PTH values in patients with advanced secondary hyperparathyroidism. Complete ablation of progressive parathyroid glands reduces circulating FGF-23 levels, simultaneously decreasing serum phosphorus and Ca x P values. These findings suggest that hyperplastic parathyroid glands, together with hyperphosphatemia, affect abnormal FGF-23 metabolism in patients with stage 5 CKD with advanced secondary hyperparathyroidism.
Department of Surgery, Renal Center, Nagoya Second Red Cross Hospital, Nagoya, Japan. tetsugar@hotmail.com
Tetsuhiko
T
Sato
Yoshihiro
Y
Tominaga
Tsuneo
T
Ueki
Norihiko
N
Goto
Susumu
S
Matsuoka
Akio
A
Katayama
Toshihito
T
Haba
Kazuharu
K
Uchida
Shohei
S
Nakanishi
Junichiro James
JJ
Kazama
Fumitake
F
Gejyo
Takeyoshi
T
Yamashita
Masafumi
M
Fukagawa
D002908:Chronic Disease; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood*; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000209:etiology / Q000601:surgery*; D007674:Kidney Diseases / Q000150:complications / Q000628:therapy; D008297:Male; D008875:Middle Aged; D016105:Parathyroidectomy; D006435:Renal Dialysis
C000717427:FGF23 protein, human; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23