title: Evaluation of human fibroblast growth factor 23 (FGF-23) C-terminal and intact enzyme-linked immunosorbent-assays in end-stage renal disease patients.
abstract: Hyperphosphataemia, calcitriol deficency and secondary hyperparathyroidism (sHPT) are common complications in end-stage chronic kidney diseases (CKD). Fibroblast Growth Factor 23 (FGF-23) is a phosphaturic peptide, secreted by the osteoblast precursors, that also inhibits renal 1-alpha-hydroxylase activitiy and tubular phosphate reabsorption by the inhibition of sodium-dependant renal phosphate transport (Na-Pi-IIa). Consequences are a decreaese of serum 1,25 dihydroxyvitamin D3 and phosphaturia. Therefore, FGF-23 plays a role in hyperphosphataemia in association with CKD and may be involved in the pathogenesis of sHPT. Increased FGF-23 may contribute to maintaining a normal serum phoshpate level in face of a processing CKD, but if the creatinine clearance is reduced to lower than 30 ml/min the capacity of this regulative mechanism ends and hyperphosphataemia results. In our investigation of end-stage renal diseases markedly increased serum FGF-23, associated with hyperphosphataemia, phosphaturia and decreased serum calcitriol and sHPT, were found. Furthermore preanalytical testing for the stability of FGF-23 was performed by comparing samples which were stored at -20 degrees C with samples that have been stored for 6 days at +4 degrees C. The simultaneous investigation of serum and EDTA plasma FGF-23 certifies the advantage of EDTA plasma in subjects with an intact renal function.
authors.affiliation: Dept. of Internal Medicine, Hospital zum Hl. Geist, Teaching Hospital of the Heinrich Heine University Duesseldorf, Kempen, Germany. w.j.fassbender@krankenhaus-kempen.de
authors.forename: W J
authors.initials: WJ
authors.lastname: Fassbender
authors.forename: V
authors.initials: V
authors.lastname: Brandenburg
authors.forename: S
authors.initials: S
authors.lastname: Schmitz
authors.forename: D
authors.initials: D
authors.lastname: Sandig
authors.forename: S A
authors.initials: SA
authors.lastname: Simon
authors.forename: J
authors.initials: J
authors.lastname: Windolf
authors.forename: U C
authors.initials: UC
authors.lastname: Stumpf
mesh_terms: D000328:Adult; D000368:Aged; D001800:Blood Specimen Collection; D003627:Data Interpretation, Statistical; D004492:Edetic Acid; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood*; D008297:Male; D008875:Middle Aged; D055550:Protein Stability
chemical_list: C000717427:FGF23 protein, human; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23; D004492:Edetic Acid