title: Identification of different phenotypes of interstitial cells in the upper and deep lamina propria of the human bladder dome.
abstract: OBJECTIVE
  There is increasing evidence for an important role of the lamina propria in bladder physiology and interstitial cells seem to have a key role in this area. Interstitial cells in the upper lamina propria have been studied most frequently. We characterized interstitial cells in the deeper lamina propria and hypothesized that the 2 interstitial cell populations have different phenotypes based on their ultrastructural and immunohistochemical properties.
  
  
  METHODS
  Tissue samples were obtained from macroscopically and microscopically normal areas of radical cystectomy specimens. A panel of immunohistochemical markers was used to characterize lamina propria interstitial cells. Single/double immunohistochemistry/immunofluorescence was performed. At a second phase electron microscopy was used to compare upper and deeper lamina propria interstitial cells.
  
  
  RESULTS
  Overall the phenotype of upper lamina propria interstitial cells was vimentin, α-smooth muscle actin, caveolin-1 and 2, PDGFRα, and nonphosphorylated and phosphorylated connexin 43 positive, and CD34 and c-kit negative. The overall phenotype of deeper lamina propria interstitial cells was vimentin, CD34 and nonphosphorylated connexin 43 positive, and α-smooth actin, caveolin-1 and 2, PDGFRα, phosphorylated connexin 43 and c-kit negative. Based on ultrastructural findings upper lamina propria interstitial cells were fibroblasts with myoid features and sparse myofibroblasts while deeper lamina propria interstitial cells were interstitial cell of Cajal-like cells.
  
  
  CONCLUSIONS
  To our knowledge this is the first study of 2 main interstitial cell populations in the upper and deeper lamina propria of the human bladder with distinct ultrastructural and immunohistochemical phenotypes. Future research is needed to elucidate whether these morphological findings reflect different roles for upper and deeper lamina propria interstitial cells in bladder physiology.
authors.affiliation: Laboratory of Experimental Urology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium; Translational Cell and Tissue Research, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium; Department of Pathology, AZ Klina, Brasschaat, Belgium. Electronic address: Thomas.gevaert@med.kuleuven.be.
authors.forename: Thomas
authors.initials: T
authors.lastname: Gevaert
authors.affiliation: Rega Institute for Medical Research, KU Leuven, Leuven, Belgium.
authors.forename: Els
authors.initials: E
authors.lastname: Vanstreels
authors.affiliation: Rega Institute for Medical Research, KU Leuven, Leuven, Belgium.
authors.forename: Dirk
authors.initials: D
authors.lastname: Daelemans
authors.affiliation: Laboratory of Experimental Urology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: Franken
authors.affiliation: Laboratory of Experimental Urology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium.
authors.forename: Frank
authors.initials: F
authors.lastname: Van Der Aa
authors.affiliation: Translational Cell and Tissue Research, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium.
authors.forename: Tania
authors.initials: T
authors.lastname: Roskams
authors.affiliation: Laboratory of Experimental Urology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium.
authors.forename: Dirk
authors.initials: D
authors.lastname: De Ridder
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D051242:Caveolin 1 / Q000378:metabolism; D018031:Connexin 43 / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D056885:Interstitial Cells of Cajal / Q000378:metabolism* / Q000648:ultrastructure; D008297:Male; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D009092:Mucous Membrane / Q000378:metabolism* / Q000648:ultrastructure; D010641:Phenotype; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000378:metabolism; D001743:Urinary Bladder / Q000378:metabolism / Q000648:ultrastructure*; D001749:Urinary Bladder Neoplasms / Q000378:metabolism / Q000473:pathology*; D014746:Vimentin / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D051242:Caveolin 1; D018031:Connexin 43; D014746:Vimentin; D019009:Proto-Oncogene Proteins c-kit; D020796:Receptor, Platelet-Derived Growth Factor alpha
keywords: fibroblasts; interstitial cells of Cajal; mucous membrane; phenotype; urinary bladder