title: A novel organotypic culture model for normal human endometrium: regulation of epithelial cell proliferation by estradiol and medroxyprogesterone acetate.
abstract: BACKGROUND
  A novel organotypic culture system was established for modelling the hormonal responses of the normal human endometrium in vitro.
  
  
  METHODS
  Endometrial epithelial cells were cultured as glandular organoids within reconstituted extracellular matrix (Matrigel) in tissue culture inserts and stromal cells on plastic below the epithelial compartment. The effects of estradiol (E2) and E2 together with medroxyprogesterone acetate (MPA) on cell proliferation and the expression of estrogen receptor alpha (ERalpha) and progesterone receptor (PR) were studied in 10 epithelial-stromal co-cultures and in three parallel monocultures of epithelial organoids.
  
  
  RESULTS
  In co-cultures, E2 was shown to increase the percentage of Ki67-positive cells by approximately 2-fold relative to untreated controls. In the presence of MPA, a significant decrease in cell proliferation was detected. Similar results were obtained when the corresponding percentages of Ki67-positive organoids were calculated instead of individual cells. In the absence of stromal fibroblasts, Ki67 epithelial labelling remained below the control value after both hormonal treatments. Epithelial organoids retained their capacity to express estrogen and progesterone receptors in culture. E2 was shown to markedly increase and MPA to down-regulate the expression of PR. The expression of ERalpha was only slightly affected by either hormonal treatment.
  
  
  CONCLUSIONS
  The present organotypic model provides a novel in vitro system in which to study the effects of steroids in the normal human endometrium both in terms of cell proliferation and gene expression. The culture system holds promise as a useful method to screen novel steroid compounds and may help to circumvent problems related to the use of animal models.
authors.affiliation: Department of Cell Biology, Medical School, 33014 University of Tampere, Tampere University Hospital, 33521Tampere, Finland. Merja.Blauer@uta.fi
authors.forename: M
authors.initials: M
authors.lastname: Bläuer
authors.forename: P K
authors.initials: PK
authors.lastname: Heinonen
authors.forename: P M
authors.initials: PM
authors.lastname: Martikainen
authors.forename: E
authors.initials: E
authors.lastname: Tomás
authors.forename: T
authors.initials: T
authors.lastname: Ylikomi
mesh_terms: D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology*; D001672:Biocompatible Materials; D002455:Cell Division / Q000187:drug effects; D018920:Coculture Techniques; D003094:Collagen; D004338:Drug Combinations; D004717:Endometrium / Q000166:cytology* / Q000378:metabolism / Q000502:physiology; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007797:Laminin; D017258:Medroxyprogesterone Acetate / Q000494:pharmacology*; D009924:Organ Culture Techniques / Q000379:methods*; D010969:Plastics; D011509:Proteoglycans; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D017154:Stromal Cells / Q000166:cytology
chemical_list: D018931:Antineoplastic Agents, Hormonal; D001672:Biocompatible Materials; D004338:Drug Combinations; D007797:Laminin; D010969:Plastics; D011509:Proteoglycans; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C059485:matrigel; D004958:Estradiol; D003094:Collagen; D017258:Medroxyprogesterone Acetate