title: Reduced podocin expression in minimal change disease and focal segmental glomerulosclerosis is related to the level of proteinuria.
abstract: BACKGROUND
  Glomerular podocyte molecules are involved in the pathogenesis of congenital nephrotic syndrome. However, their role in primary nephrotic syndrome is not clear. This study investigated the expression of nephrin, podocin and synaptopodin in primary nephrotic syndrome.
  
  
  METHODS
  Eighty-seven patients with primary nephrotic syndrome including minimal change disease (MCD), focal segmental glomerulosclerosis (FSGS), membranous nephropathy (MN) and membranoproliferative glomerulonephritis Type I (MPGN) were included in the study. Glomerular expression of nephrin, podocin and synaptopodin was studied in renal biopsies by immunofluorescence and immunohistochemistry. Correlation of expression with clinical and biochemical parameters was performed.
  
  
  RESULTS
  The pattern of expression for all podocyte proteins in controls was uniform fine granular along the capillary walls towards the visceral epithelial cell aspect. Glomerular expression of nephrin was present in all renal biopsies and was similar to that in controls. Glomerular synaptopodin expression was seen in all MN and MPGN patients, while it was seen in 74 % (17/23) MCD and 93.5 % (29/31) FSGS. Reduced synaptopodin expression showed no correlation with clinical and biochemical factors. Podocin expression was present in 5/23 MCD (22 %), 3/31 FSGS (9.6 %), 13/17 MN (76.4 %) and 13/16 MPGN (81 %) patients. The reduced expression of podocin significantly correlated with the degree of proteinuria (p = 0.032). No correlation with age, gender and serum creatinine level was observed.
  
  
  CONCLUSIONS
  Reduction of glomerular podocin expression found in MCD and FSGS is related to the amount of proteinuria. Our findings suggest that alteration in podocyte phenotype may not be a primary event and may reflect the degree of podocyte injury in primary nephrotic syndrome.
authors: Department of Pathology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, 226014, India, vinita@sgpgi.ac.in.
authors: Vinita
authors: V
authors: Agrawal
authors: Narayan
authors: N
authors: Prasad
authors: Manoj
authors: M
authors: Jain
authors: Rakesh
authors: R
authors: Pandey
mesh_terms: D000293:Adolescent; D000328:Adult; D003404:Creatinine / Q000652:urine; D015432:Glomerulonephritis, Membranoproliferative / Q000378:metabolism; D005923:Glomerulosclerosis, Focal Segmental / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000096:biosynthesis*; D007678:Kidney Glomerulus / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis*; D008840:Microfilament Proteins / Q000096:biosynthesis; D008875:Middle Aged; D009402:Nephrosis, Lipoid / Q000378:metabolism; D009404:Nephrotic Syndrome / Q000378:metabolism; D050199:Podocytes / Q000378:metabolism; D011507:Proteinuria / Q000378:metabolism*
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D008840:Microfilament Proteins; C407223:NPHS2 protein; C503967:SYNPO protein, human; C113267:nephrin; D003404:Creatinine
references: Pediatr Nephrol. 2004 Mar;19(3):300-5
references: 14747939
references: J Am Soc Nephrol. 2001 Feb;12(2):289-296
references: 11158218
references: J Am Soc Nephrol. 2007 Nov;18(11):2987-95
references: 17942957
references: Kidney Int. 2001 Jan;59(1):118-25
references: 11135064
references: J Am Soc Nephrol. 2003 Aug;14(8):2063-71
references: 12874460
references: Am J Kidney Dis. 2002 Nov;40(5):964-73
references: 12407641
references: BMC Nephrol. 2008 Sep 29;9:13
references: 18823551
references: J Am Soc Nephrol. 2009 Oct;20(10):2181-9
references: 19713307
references: Kidney Int. 2003 Dec;64(6):2092-9
references: 14633131
references: Am J Hum Genet. 1999 Jan;64(1):51-61
references: 9915943
references: Am J Pathol. 2002 Jan;160(1):131-9
references: 11786407
references: Clin J Am Soc Nephrol. 2007 Jan;2(1):31-7
references: 17699384
references: J Am Soc Nephrol. 1999 Jan;10(1):51-61
references: 9890309
references: Ren Fail. 2010 Jan;32(3):372-9
references: 20370455
references: Am J Nephrol. 2003 Sep-Oct;23(5):353-60
references: 12915777
references: Nephrol Dial Transplant. 2002 Mar;17(3):478-84
references: 11865096
references: Am J Pathol. 2001 May;158(5):1723-31
references: 11337370