title: A method for isolation and identification of urinary biomarkers in patients with diabetic nephropathy.
abstract: OBJECTIVE
  The poor performance of current tests for predicting the onset, progression and treatment response of diabetic nephropathy has engendered a search for more sensitive and specific urinary biomarkers. Our goal was to develop a new method for protein biomarker discovery in urine from these patients.
  
  
  METHODS
  We analyzed urine from normal subjects and patients with early and advanced nephropathy. Proteins were separated using a novel analysis process including immunodepletion of high-abundance proteins followed by two-stage LC fractionation of low-abundance proteins. The proteins in the fractions were sequenced using MS/MS.
  
  
  RESULTS
  Immunodepletion of selected high-abundance proteins followed by two-stage LC produced approximately 700 fractions, each less complex and more amenable to analysis than the mixture and requiring minimal processing for MS identification. Comparison of fractions between normal and diabetic nephropathy subjects revealed several low-abundance proteins that reproducibly distinguished low glomerular filtration rate (GFR) from both high GFR diabetic and normal subjects, including uteroglobin, a protein previously associated with renal scarring.
  
  
  CONCLUSIONS
  We developed a novel method to identify low-abundance urinary proteins that enables the discovery of potential biomarkers to improve the diagnosis and management of patients with diabetic nephropathy.
authors.affiliation: University of Texas Southwestern Medical Center at Dallas, Harry Hines Boulevard, Dallas, TX, USA.
authors.forename: Wayne G
authors.initials: WG
authors.lastname: Fisher
authors.forename: Jessica E
authors.initials: JE
authors.lastname: Lucas
authors.forename: Uzma F
authors.initials: UF
authors.lastname: Mehdi
authors.forename: Danna W
authors.initials: DW
authors.lastname: Qunibi
authors.forename: Harold R
authors.initials: HR
authors.lastname: Garner
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Rosenblatt
authors.forename: Robert D
authors.initials: RD
authors.lastname: Toto
mesh_terms: D015415:Biomarkers / Q000652:urine; D056148:Chromatography, Reverse-Phase / Q000379:methods*; D003928:Diabetic Nephropathies / Q000652:urine*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011506:Proteins / Q000032:analysis / Q000302:isolation & purification; D014462:Ultrafiltration; D016482:Urinalysis / Q000379:methods*
chemical_list: D015415:Biomarkers; D011506:Proteins