title: Growth, differentiation and senescence of normal human urothelium in an organ-like culture.
abstract: OBJECTIVE
  To examine the kinetics of growth, differentiation and senescence of normal human urothelium in an organoid-like culture model.
  
  
  METHODS
  Micro-dissected normal human urothelium explants were grown on porous membranes pretreated with various matrix components. Between 5 and 30 days of culture, cell proliferation was assessed by BrdU incorporation. Differentiation was evaluated on the basis of cytokeratin (Ck) and uroplakin (UP) expression. Epidermal growth factor family mRNA expression was monitored during explant outgrowth. Senescence was assessed by measuring endogenous beta-galactosidase activity and p16(INK4a) mRNA expression.
  
  
  RESULTS
  Collagen IV was the most efficient matrix component for urothelial cell expansion. BrdU incorporation by urothelial cells was 5% between 15 and 30 days, corresponding to steady-state urothelium in vivo. Heparin-binding EGF (HB-EGF), Amphiregulin (AR) and Transforming Growth Factor alpha (TGF alpha) expression correlated with increased cell proliferation. UPII expression was stable throughout culture. P16(INK4a) mRNA expression and beta-galactosidase activity increased on day 25, giving signs of senescence.
  
  
  CONCLUSIONS
  This model retains many characteristics of the urothelium in vivo. It can be used for pharmacological studies between 15 to 25 days and to study mechanisms such as wound healing, proliferation and senescence.
authors.affiliation: INSERM EMI 03-37, Faculté de Médecine, 8, Rue du Général Sarrail, Université Paris 12, 94000 Créteil cedex, France.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Daher
authors.forename: Willem I
authors.initials: WI
authors.lastname: de Boer
authors.forename: Marie-Aude
authors.initials: MA
authors.lastname: Le Frère-Belda
authors.forename: Laurence
authors.initials: L
authors.lastname: Kheuang
authors.forename: Claude C
authors.initials: CC
authors.lastname: Abbou
authors.forename: François
authors.initials: F
authors.lastname: Radvanyi
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Jaurand
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Thiery
authors.forename: Sixtina
authors.initials: S
authors.lastname: Gil Diez de Medina
authors.forename: Dominique K
authors.initials: DK
authors.lastname: Chopin
mesh_terms: D002454:Cell Differentiation; D002455:Cell Division; D016922:Cellular Senescence; D006801:Humans; D009924:Organ Culture Techniques; D019459:Urothelium / Q000166:cytology / Q000254:growth & development