title: Oxytocin receptor expression in smooth muscle cells of peritoneal endometriotic lesions and ovarian endometriotic cysts.
abstract: OBJECTIVE
  To investigate the expression of oxytocin receptor (OTR) in peritoneal and ovarian endometriotic lesions.
  
  
  METHODS
  Retrospective nonrandomized study.
  
  
  METHODS
  University hospital endometriosis research center.
  
  
  METHODS
  Premenopausal women with histologically confirmed endometriosis were selected. Peritoneal endometriotic lesions (n = 120); ovarian endometriotic cysts (n = 40); peritoneal biopsies, distant from the endometriotic lesion (n = 55); and unaffected peritoneal biopsies from patients without endometriosis (n = 11) were obtained. Hysterectomy specimens from patients without endometriosis and/or adenomyosis were used for controls (n = 10).
  
  
  METHODS
  Histopathological examination of peritoneal and ovarian specimens for OTR expression and identification of smooth muscle cells by immunohistochemistry staining with antibodies against OTR and smooth muscle actin. In addition, Western blot analysis, double-immunofluorescence, and in vitro studies with primary cell cultures have been performed.
  
  
  METHODS
  Comparison of the immunoreactive score of the OTR and smooth muscle actin expression with the smooth muscle content in peritoneum with and without endometriosis.
  
  
  RESULTS
  In the epithelial cells of endometriotic lesions, we could demonstrate a high OTR expression. The stromal cells were OTR negative with the exception of some single cells. By using a monoclonal anti-smooth muscle actin antibody, these cells could be identified as intrastromal OTR-positive smooth muscle cells. The peritoneum of women with endometriosis shows a significantly higher smooth muscle content than the peritoneum of women without endometriosis. There were no significant differences between the smooth muscle content of active or inactive lesions and the stage of disease.
  
  
  CONCLUSIONS
  Oxytocin receptor is expressed in smooth muscle cells and epithelial cells of peritoneal endometriotic lesions and ovarian endometriotic cysts. The inhibition of OTR by specific inhibitors might be a useful approach for the treatment of endometriosis-associated pain.
authors.affiliation: Endometriosis Research Center Berlin, Department of Gynecology, Charité, Campus Benjamin Franklin, Hindenburgdamm 30, 12200 Berlin, Germany.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Mechsner
authors.forename: Julia
authors.initials: J
authors.lastname: Bartley
authors.forename: Christoph
authors.initials: C
authors.lastname: Loddenkemper
authors.forename: David S
authors.initials: DS
authors.lastname: Salomon
authors.forename: Anna
authors.initials: A
authors.lastname: Starzinski-Powitz
authors.forename: Andreas D
authors.initials: AD
authors.lastname: Ebert
mesh_terms: D000328:Adult; D015153:Blotting, Western; D004717:Endometrium / Q000378:metabolism / Q000473:pathology*; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D008679:Metaplasia; D008875:Middle Aged; D032389:Myocytes, Smooth Muscle / Q000378:metabolism* / Q000473:pathology; D009215:Myometrium / Q000378:metabolism / Q000473:pathology; D010048:Ovarian Cysts / Q000378:metabolism / Q000473:pathology*; D010537:Peritoneum / Q000378:metabolism / Q000473:pathology*; D018045:Receptors, Oxytocin / Q000378:metabolism*
chemical_list: D018045:Receptors, Oxytocin