title: Serum soluble Klotho protein level is associated with residual diuresis in incident peritoneal dialysis patients.
abstract: OBJECTIVE
  Active vitamin D (1,25-dihydroxyvitamin D₃), PTH, fibroblast growth factor-23 (FGF-23) and Klotho protein are key regulators of phosphate metabolism. Hyperphosphatemia and increased FGF-23 level in patients with end-stage renal disease are associated with increased morbidity and mortality. The relationships among key regulators of phosphate metabolism are still being investigated. FGF-23, the humoral factor involved in phosphate metabolism, is strongly associated with serum phosphorus level. Klotho, a transmembrane protein expressed primarily in renal tubules, functions as an obligatory co-receptor for FGF-23. The soluble form of Klotho, produced by the shedding of the transmembrane protein, is detectable in body fluids. The purpose of the study was to assess if serum soluble alpha-Klotho level was related to phosphate metabolism parameters and residual renal function (RRF) in incident peritoneal dialysis (PD) patients.
  
  
  METHODS
  Thirty-five clinically stable patients 4 to 6 weeks after the onset of PD were included in the study. For each patient, clinical and laboratory data were reviewed. Serum phosphorus concentration, urinary and peritoneal phosphate clearance, serum FGF-23 and soluble Klotho protein concentrations were determined.
  
  
  RESULTS
  Serum soluble alpha-Klotho was strongly negatively correlated with 24-hour diuresis (Rs = -0.55, p = 0.004) and renal phosphate clearance (Rs = -0.40, p = 0.049), but not with RRF.
  
  
  CONCLUSIONS
  Serum soluble Klotho protein concentration is inversely related to residual diuresis and renal phosphate clearance in incident PD patients.
authors.affiliation: Department of Nephrology, Transplantology and Internal Medicine, Pomeranian Medical University, Szczecin, Poland. irys@pum.edu.pl
authors.forename: Edyta
authors.initials: E
authors.lastname: Golembiewska
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Safranow
authors.forename: Joanna
authors.initials: J
authors.lastname: Kabat-Koperska
authors.forename: Marek
authors.initials: M
authors.lastname: Myślak
authors.forename: Kazimierz
authors.initials: K
authors.lastname: Ciechanowski
mesh_terms: D000328:Adult; D004231:Diuresis / Q000502:physiology*; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000378:metabolism*; D005966:Glucuronidase / Q000097:blood*; D006801:Humans; D007668:Kidney / Q000503:physiopathology; D007676:Kidney Failure, Chronic / Q000503:physiopathology*; D000090265:Klotho Proteins; D008297:Male; D008875:Middle Aged; D010531:Peritoneal Dialysis, Continuous Ambulatory; D010710:Phosphates / Q000378:metabolism
chemical_list: C000717427:FGF23 protein, human; D010710:Phosphates; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23; D005966:Glucuronidase; D000090265:Klotho Proteins