title: The relationship between the soluble Klotho protein and the residual renal function among peritoneal dialysis patients.
abstract: BACKGROUND
  Klotho has been investigated as an anti-aging protein that is predominantly expressed in the distal convoluted tubules in the kidneys and in the choroid plexus of the brain. The purpose of the present study was to determine the relationship between the soluble form of Klotho and renal function in chronic peritoneal dialysis (PD) patients, a relationship which remains poorly understood.
  
  
  METHODS
  The soluble Klotho levels in the serum, urine, and peritoneal dialysate obtained from thirty-six PD patients were determined by a sandwich enzyme-linked immunosorbent assay system.
  
  
  RESULTS
  The amount of urinary excreted soluble Klotho over 24 h ranged from 1.54 to 1774.4 ng/day (median 303.2 ng/day; interquartile range [IR] 84.1-498.5), while the serum soluble Klotho concentration ranged from 194.4 to 990.4 pg/ml (mean 553.7 ± 210.4 pg/ml). The amount of urinary Klotho excretion was significantly correlated with residual renal function. However, there was no apparent correlation between the serum soluble Klotho levels and the residual renal function. Klotho was also detected in the 24-h dialysate collections. There was a significant correlation between the peritoneal Klotho excretion and the amount of albumin contained in the dialysate collections (r = 0.798, p < 0.01).
  
  
  CONCLUSIONS
  The total amount of urinary excreted Klotho, but not the serum level of soluble Klotho, may be a potential biomarker for assessing the residual renal function among PD patients. Whether our findings are also valid for chronic kidney disease patients overall should therefore be evaluated in greater detail.
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan. tetsu-a@jichi.ac.jp
authors.forename: Tetsu
authors.initials: T
authors.lastname: Akimoto
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Shiizaki
authors.forename: Taro
authors.initials: T
authors.lastname: Sugase
authors.forename: Yuko
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Yoshizawa
authors.forename: Naoko
authors.initials: N
authors.lastname: Otani
authors.forename: Akihiko
authors.initials: A
authors.lastname: Numata
authors.forename: Eri
authors.initials: E
authors.lastname: Takeshima
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Yamazaki
authors.forename: Takuya
authors.initials: T
authors.lastname: Miki
authors.forename: Chiharu
authors.initials: C
authors.lastname: Ito
authors.forename: Johanne V
authors.initials: JV
authors.lastname: Pastor
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Iwazu
authors.forename: Osamu
authors.initials: O
authors.lastname: Saito
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Muto
authors.forename: Makoto
authors.initials: M
authors.lastname: Kuro-o
authors.forename: Eiji
authors.initials: E
authors.lastname: Kusano
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D005966:Glucuronidase / Q000097:blood / Q000378:metabolism* / Q000652:urine; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D007676:Kidney Failure, Chronic / Q000503:physiopathology*; D000090265:Klotho Proteins; D010530:Peritoneal Dialysis; D012995:Solubility
chemical_list: D015415:Biomarkers; D005966:Glucuronidase; D000090265:Klotho Proteins