title: Tissue integrity is essential for ectopic implantation of human endometrium in the chicken chorioallantoic membrane.
abstract: BACKGROUND
  Not all women with patent tubes develop clinically manifest endometriosis. Quality and quantity of endometrium in retrograde menstruation may be the determining factor in the development of the disease. We hypothesize that retrograde shedding of endometrial fragments with preserved integrity facilitates implantation of endometrium in ectopic locations, resulting in endometriotic lesion development. We evaluate the impact of tissue integrity on the success of endometriosis-like lesion development in the chicken embryo chorioallantoic membrane (CAM) model.
  
  
  METHODS
  Menstrual and non-menstrual (cyclic) endometrium were collected by biopsy, and either minced or enzymatically dispersed. Spontaneously shed menstrual effluent was collected by a menstrual cup, and cells and tissue were isolated. We evaluated whether infiltration or lesion formation in the CAM occurred after transplantation of endometrium onto the CAM.
  
  
  RESULTS
  Transplantation of biopsied menstrual and cyclic endometrium fragments, and of endometrium fragments >1 mm(3) isolated from menstrual effluent, resulted in lesion formation. Transplantation of endometrial cells isolated from menstrual effluent did not lead to lesion formation. After transplantation of digested biopsied cyclic endometrium, infiltration in the CAM but no lesions were observed.
  
  
  CONCLUSIONS
  In the CAM assay, integrity of tissue architecture determines success of implantation of human endometrium in ectopic locations.
authors.affiliation: Departments of Obstetrics and Gynaecology, Academisch ziekenhuis Maastricht, PO Box 5800, 6202 AZ Maastricht, The Netherlands. ana@sgyn.azm.nl
authors.forename: Annemiek W
authors.initials: AW
authors.lastname: Nap
authors.forename: Patrick G
authors.initials: PG
authors.lastname: Groothuis
authors.forename: Ayse Y
authors.initials: AY
authors.lastname: Demir
authors.forename: Jacques W M
authors.initials: JW
authors.lastname: Maas
authors.forename: Gerard A J
authors.initials: GA
authors.lastname: Dunselman
authors.forename: Anton F P M
authors.initials: AF
authors.lastname: de Goeij
authors.forename: Johannes L H
authors.initials: JL
authors.lastname: Evers
mesh_terms: D000482:Allantois / Q000601:surgery*; D000818:Animals; D002455:Cell Division; D002642:Chick Embryo; D002823:Chorion / Q000601:surgery*; D004715:Endometriosis / Q000209:etiology* / Q000473:pathology; D004717:Endometrium / Q000033:anatomy & histology / Q000473:pathology / Q000637:transplantation*; D005260:Female; D006801:Humans; D008598:Menstruation / Q000502:physiology; D014183:Transplantation, Heterologous; D016042:Transplantation, Heterotopic