title: The expression of activin-betaA- and -betaB-subunits, follistatin, and activin type II receptors in fallopian tubes bearing an ectopic pregnancy.
abstract: BACKGROUND
  Ectopic pregnancy is a major cause of maternal morbidity and mortality with increasing incidence worldwide.
  
  
  OBJECTIVE
  We investigated whether epithelia from Fallopian tubes (FTs) bearing an ectopic pregnancy differ from normal tubes in expression of TGF-beta family and related proteins and their receptors.
  
  
  METHODS
  Because it is not possible to collect FTs from women carrying a healthy pregnancy, we studied tissue collected at the time of hysterectomy for benign disease. Women were injected with human chorionic gonadotropin in the days leading up to hysterectomy to produce a state of pseudopregnancy. Pseudopregnancy status was confirmed by the presence of high serum progesterone levels and the decidualization of the endometrium. Fifteen FTs bearing ectopic pregnancy and six pseudopregnant tubes were collected and examined using immunohistochemistry and quantitative RT-PCR.
  
  
  RESULTS
  Immunohistochemistry demonstrated clear staining for the betaA- and betaB-subunits, type II receptor group comprising the activin type IIA and type IIB receptors, and follistatin, which increased in intensity from the isthmus to the ampulla in both models. However, the intensity of expression of these molecules was stronger in the ectopic pregnancy group when compared with the pseudopregnant group. Quantitative RT-PCR showed significant decrease in mRNA levels of betaA-subunit, activin type IIA and IIB receptors, and follistatin in ectopic group (P < 0.05) but no changes in betaB-subunit (P > 0.05). Overall, there was an apparent paradox of high concentration of protein but low mRNA expression.
  
  
  CONCLUSIONS
  Activin-A may stimulate tubal decidualization and trophoblast invasion. A better understanding of the mechanism by which an embryo implants in the tubal epithelium may lead to improved methods for early diagnosis and/or management of ectopic pregnancy.
authors.affiliation: Academic Unit of Reproductive and Developmental Medicine, Level 4, The Jessop Wing, Royal Hallamshire Hospital, Sheffield S10 2SF, United Kingdom.
authors.forename: Bassem
authors.initials: B
authors.lastname: Refaat
authors.forename: Saad
authors.initials: S
authors.lastname: Amer
authors.forename: Bolarinde
authors.initials: B
authors.lastname: Ola
authors.forename: Neil
authors.initials: N
authors.lastname: Chapman
authors.forename: William
authors.initials: W
authors.lastname: Ledger
mesh_terms: D030301:Activin Receptors, Type II / Q000096:biosynthesis* / Q000235:genetics; D000328:Adult; D005187:Fallopian Tubes / Q000378:metabolism*; D005260:Female; D038681:Follistatin / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D028322:Inhibin-beta Subunits / Q000096:biosynthesis* / Q000235:genetics; D011247:Pregnancy; D011271:Pregnancy, Ectopic / Q000378:metabolism*; D011555:Pseudopregnancy / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D038681:Follistatin; C422402:INHBB protein, human; D012333:RNA, Messenger; C103008:inhibin beta A subunit; D028322:Inhibin-beta Subunits; D030301:Activin Receptors, Type II