title: Ezrin--a useful factor in the prognosis of nephrotic syndrome in children: an immunohistochemical approach.
abstract: BACKGROUND
  Minimal change disease (MCD) and diffuse mesangial proliferation (DMP) are the most common pathomorphological forms of nephrotic syndrome glomerulopathies in children. The clinical course of DMP can be characterised by either DMP-sensitivity (DMP-S) or DMP-resistance (DMP-R) to steroids, resulting in an unfavourable course of the glomerulopathy. Although the clinical processes of DMP-S and DMP-R are initially identical, resistance to steroids may be foreseen by the immunohistochemical expression of cytoskeleton-associated proteins in podocytes.
  
  
  OBJECTIVE
  To estimate the immunohistochemical expression of ezrin in children with MCD, DMP and focal segmental glomerulosclerosis (FSGS) and to evaluate its usefulness in predicting resistance to steroids.
  
  
  METHODS
  Renal biopsy specimens of patients with MCD (n = 15), DMP (n = 16) and FSGS (n = 6) were taken. The control tissue consisted of normal-appearing cortex taken from kidneys resected for localised neoplasms (n = 6). The indirect immunohistochemical protocol for the use of a monoclonal antibody directed against ezrin was used.
  
  
  RESULTS
  The immunohistochemical expression of ezrin in cases progressively reduced from MCD to DMP-S to DMP-R to FSGS. Except for DMP-R and FSGS (p>0.05), the difference in ezrin expression in podocytes was significant.
  
  
  CONCLUSIONS
  Ezrin can be a potent marker of podocyte injury (podocytopathy) and may help in the histological qualification of MCD, DMP and FSGS. The increased permeability of the filtration barrier in steroid-resistant and proteinuric glomerulopathies may be a consequence of subcellular changes in podocyte-associated proteins following decreased expression of ezrin.
authors.affiliation: Department of Pediatric Cardiology and Nephrology, Poznan University of Medical Sciences, Poznan, Poland. dostalska@interia.pl
authors.forename: D
authors.initials: D
authors.lastname: Ostalska-Nowicka
authors.forename: J
authors.initials: J
authors.lastname: Zachwieja
authors.forename: M
authors.initials: M
authors.lastname: Nowicki
authors.forename: E
authors.initials: E
authors.lastname: Kaczmarek
authors.forename: A
authors.initials: A
authors.lastname: Siwinska
authors.forename: M
authors.initials: M
authors.lastname: Witt
mesh_terms: D000293:Adolescent; D015415:Biomarkers / Q000378:metabolism; D001706:Biopsy; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004351:Drug Resistance; D005260:Female; D005923:Glomerulosclerosis, Focal Segmental / Q000175:diagnosis / Q000188:drug therapy / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D007678:Kidney Glomerulus / Q000378:metabolism; D008297:Male; D050527:Mesangial Cells / Q000378:metabolism; D009402:Nephrosis, Lipoid / Q000175:diagnosis / Q000188:drug therapy / Q000378:metabolism; D009404:Nephrotic Syndrome / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism; D050199:Podocytes / Q000378:metabolism; D011379:Prognosis; D012795:Sialoglycoproteins / Q000378:metabolism; D013256:Steroids / Q000627:therapeutic use; D000099149:Ezrin
chemical_list: D015415:Biomarkers; D003598:Cytoskeletal Proteins; D012795:Sialoglycoproteins; D013256:Steroids; D000099149:Ezrin; C001643:podocalyxin