title: Endometriosis also affects the decidua in contact with the fetal membranes during pregnancy.
abstract: OBJECTIVE
  Are the fetal membranes of women affected with endometriosis similar to those from disease-free women?
  
  
  CONCLUSIONS
  Decidua of women with endometriosis is able to generate endometriotic-like lesions in contact with the fetal membranes.
  
  
  BACKGROUND
  Eutopic endometrium of women affected with endometriosis presents compromised properties. Endometrium undergoes decidualisation to accept and to further control the conceptus development during pregnancy. Decidualized endometrium is in close contact with the chorionic membrane and forms the choriodecidual layer, a major maternal-fetal interface.
  
  
  METHODS
  This is a laboratory case-control study involving diseased versus control samples. Eleven case samples and 11 control samples were collected from women in a tertiary care/research center between November 2011 and December 2013.
  
  
  METHODS
  Participants were consecutive pregnant women affected with confirmed endometriosis and disease free women, who underwent Cesarean section before labor for obstetrical indication. The choriodecidual tissues were characterized using histology, immunohistochemistry, transcriptomic and whole genome CpG methylation analyses.
  
  
  RESULTS
  We demonstrate for the first time the presence of endometriotic-like lesions within the decidual side of the choriodecidua of the fetal membranes from women affected with severe endometriosis. Fetal membranes from women affected with endometriosis exhibited glandular components in the choriodecidual layer surrounded by enlarged decidualized cells disseminated along the entire membrane surface. Significant deregulation (variation of expression ≥2, P-value ≤0.05) was observed for 2773 genes known to be enriched in processes involved in glandular function, endocrine and nervous system, neoangiogenesis, and autoimmune disease. CpG methylation analysis revealed 5999 differentially methylated regions with a P-value ≤0.05.
  
  
  CONCLUSIONS
  We studied women who delivered at term by Cesarean section before labor, following an uneventful pregnancy. Notwithstanding this, one cannot exclude that the presence of disseminated endometriotic lesions within the choriodecidual layer of the fetal membranes may disturb the anatomical integrity and/or the function of the membranes in some women with endometriosis.
  
  
  CONCLUSIONS
  Our results shed new light on the capability of the diseased decidua to develop lesions not only at ectopic autologous locations, but also on the semi-allogenous fetal membranes, a particularly immunotolerant environment.
authors.affiliation: Cochin Institute, Inserm U1016, CNRS 8104, Université Paris Descartes, Paris, France Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Port Royal - Hôpitaux Universitaires Paris Centre, Service de Gynécologie-Obstétrique II et Médecine de la Reproduction, Paris, France Université Paris Descartes, DHU Risques et Grossesse, Paris, France louismarcellin@gmail.com.
authors.forename: L
authors.initials: L
authors.lastname: Marcellin
authors.affiliation: Cochin Institute, Inserm U1016, CNRS 8104, Université Paris Descartes, Paris, France Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Port Royal - Hôpitaux Universitaires Paris Centre, Service de Gynécologie-Obstétrique II et Médecine de la Reproduction, Paris, France.
authors.forename: P
authors.initials: P
authors.lastname: Santulli
authors.affiliation: Cochin Institute, Inserm U1016, CNRS 8104, Université Paris Descartes, Paris, France Université Paris Descartes, DHU Risques et Grossesse, Paris, France.
authors.forename: J
authors.initials: J
authors.lastname: Gogusev
authors.affiliation: Cochin Institute, Inserm U1016, CNRS 8104, Université Paris Descartes, Paris, France.
authors.forename: C
authors.initials: C
authors.lastname: Lesaffre
authors.affiliation: Cochin Institute, Inserm U1016, CNRS 8104, Université Paris Descartes, Paris, France.
authors.forename: S
authors.initials: S
authors.lastname: Jacques
authors.affiliation: Cochin Institute, Inserm U1016, CNRS 8104, Université Paris Descartes, Paris, France Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Port Royal - Hôpitaux Universitaires Paris Centre, Service de Gynécologie-Obstétrique II et Médecine de la Reproduction, Paris, France.
authors.forename: C
authors.initials: C
authors.lastname: Chapron
authors.affiliation: Université Paris Descartes, DHU Risques et Grossesse, Paris, France Université Paris Descartes, Faculté de Médecine, AP- HP, Groupe Hospitalier Universitaire Ouest, Centre Hospitalier Universitaire Cochin Broca Hôtel Dieu, Port Royal Maternity, Department of Gynecology Obstetrics I, Paris, France.
authors.forename: F
authors.initials: F
authors.lastname: Goffinet
authors.affiliation: Cochin Institute, Inserm U1016, CNRS 8104, Université Paris Descartes, Paris, France Université Paris Descartes, DHU Risques et Grossesse, Paris, France.
authors.forename: D
authors.initials: D
authors.lastname: Vaiman
authors.affiliation: Cochin Institute, Inserm U1016, CNRS 8104, Université Paris Descartes, Paris, France Université Paris Descartes, DHU Risques et Grossesse, Paris, France.
authors.forename: C
authors.initials: C
authors.lastname: Méhats
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002585:Cesarean Section; D015331:Cohort Studies; D018899:CpG Islands; D019175:DNA Methylation; D003656:Decidua / Q000378:metabolism / Q000473:pathology*; D004715:Endometriosis / Q000235:genetics / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D004717:Endometrium / Q000378:metabolism / Q000473:pathology*; D005321:Extraembryonic Membranes / Q000378:metabolism / Q000473:pathology*; D005260:Female; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D007150:Immunohistochemistry; D010922:Placenta Diseases / Q000235:genetics / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000235:genetics / Q000378:metabolism; D012720:Severity of Illness Index; D047929:Term Birth
chemical_list: D011257:Pregnancy Proteins
keywords: decidua; endometriosis; fetal membranes; pregnancy