title: Plasma and urine proteomic profiles in childhood idiopathic nephrotic syndrome.
abstract: OBJECTIVE
  Idiopathic nephrotic syndrome (NS) is characterized by proteinuria, edema, and hypoalbuminemia. The aim of the study was to identify differentially expressed proteins in urine and plasma during NS compared with remission.
  
  
  METHODS
  Plasma and urine samples were collected during NS and at remission. Proteomic profiling was performed by iTRAQ labeling followed by nano-LC-MS/MS to yield data on relative protein amounts. Protein validation was performed by ELISA.
  
  
  RESULTS
  A total of 388 and 425 proteins were detected in plasma and urine, respectively. In total, 18 plasma and 38 urinary proteins were significantly altered (p <0.05). E-cadherin was one of the proteins with reduced urinary concentration during NS, a finding validated by ELISA. The slit diaphragm protein P-cadherin was identified by nano-LC-MS/MS and shown to be reduced in urine during NS by ELISA.
  
  
  CONCLUSIONS
  The present study identified more than 50 differentially altered proteins comparing NS with remission. Several proteins were found to be linked to the major clinical symptoms of NS, and further studies must elucidate if P-cadherin is involved in proteinuria during NS, and if low urinary E-cadherin level is linked to altered epithelial cell to cell contact in the distal part of the nephron.
authors.affiliation: Department of Peadiatrics, Aarhus University Hospital, Skejby, Aarhus, Denmark. rfa@ki.au.dk
authors.forename: René Frydensbjerg
authors.initials: RF
authors.lastname: Andersen
authors.forename: Johan
authors.initials: J
authors.lastname: Palmfeldt
authors.forename: Bente
authors.initials: B
authors.lastname: Jespersen
authors.forename: Niels
authors.initials: N
authors.lastname: Gregersen
authors.forename: Søren
authors.initials: S
authors.lastname: Rittig
mesh_terms: D000293:Adolescent; D015820:Cadherins / Q000652:urine; D002648:Child; D002853:Chromatography, Liquid; D003710:Demography; D004797:Enzyme-Linked Immunosorbent Assay; D006466:Hemopexin / Q000378:metabolism; D006801:Humans; D007223:Infant; D013058:Mass Spectrometry; D008970:Molecular Weight; D009404:Nephrotic Syndrome / Q000097:blood* / Q000652:urine*; D020543:Proteome / Q000737:chemistry / Q000378:metabolism*; D040901:Proteomics / Q000379:methods*; D015203:Reproducibility of Results
chemical_list: D015820:Cadherins; D020543:Proteome; D006466:Hemopexin