Does dietary phosphorus influence FGF23 concentrations in fibrous dysplasia patients?

MAROTTE C; GUERRERO L; SÁNCHEZ AL; SOMOZA JI; BAGUR A; OLIVERI B; PARISI MS

Québec, Canadá

Congreso; 30th Annual Meeting of the American Society for Bone and Mineral Research (ASBMR); 2008

ASBMR

High levels of fibroblast growth factor 23 (FGF-23) have been reported In Fibrous Dysplasia (FD) patients. However, whether or not phosphate physiological regulation mechanisms are maintained is unknown. Objective: to determine whether serum FGF-23 concentrations are regulated by dietary phosphorus (P) in FD patients.We studied 6 polyostotic FD patients (2M, 4W) aged 31.5±11.2 y (X± SD) (r: 20-50), and 6 healthy controls (1M, 5W) aged 33.4±15.5y (r: 20-57). Patients and controls performed a 5 days control diet with 1500mg/d of P. After a free diet period (3-27d), FD patients performed a 5 days restriction diet with 625mg/d of P. All the subjects filled a daily meals record. P and calcium total intakes were calculated. Lab tests after each diet: serum FGF-23 (C-terminal, Inmutopics), 1,25(OH)2D, P, Ca, iPTH, and creatinine; and urinary P, Ca, and creatinine. Tubular reabsorption of P (TRP) was calculated.After the control diet, P intakes were: 1145±116md/d in patients, and 917±250mg/d in controls (ns). After the restriction diet, in FD patients, P intake was: 712±67md/d (p