title: Implantation-dependent expression of trophinin by maternal fallopian tube epithelia during tubal pregnancies: possible role of human chorionic gonadotrophin on ectopic pregnancy.
abstract: Trophinin, tastin, and bystin have been identified as molecules potentially involved in human embryo implantation. Both trophoblasts and endometrial epithelial cells express trophinin, which mediates apical cell adhesion through homophilic trophinin-trophinin binding. We hypothesized that trophinin's function in embryo implantation is unique to humans and investigated the expression of trophinin, tastin, and bystin in ectopic pregnancy, a condition unique to humans. In tubal pregnancies, high levels of all three were found in both trophoblasts and fallopian tubal epithelia. Trophinin expression in maternal cells was particularly high in the area adjacent to the trophoblasts, whereas trophinin was barely detectable in intact fallopian tubes from women with in utero pregnancies or without pregnancies. When explants of intact fallopian tube were incubated with the human chorionic gonadotrophin (hCG), trophinin expression was enhanced in epithelial cells. Since the trophectoderm of the human blastocyst secretes hCG before and after implantation, these results suggest that hCG from the human embryo induces trophinin expression by maternal cells. As both beta-subunit of hCG and trophinin genes have diverged in mammals, the present study suggests a unique role of hCG and trophinin in human embryo implantation, including the pathogenesis of ectopic pregnancy.
authors: Departments of Pathology, Internal Medicine, Surgery, and Laboratory Medicine, Shinshu University School of Medicine, Matsumoto, Japan. jun@hsp.md.shinshu-u.ac.jp
authors: Jun
authors: J
authors: Nakayama
authors: Daisuke
authors: D
authors: Aoki
authors: Tomoaki
authors: T
authors: Suga
authors: Tomoya O
authors: TO
authors: Akama
authors: Satoshi
authors: S
authors: Ishizone
authors: Hirohito
authors: H
authors: Yamaguchi
authors: Kazuhiko
authors: K
authors: Imakawa
authors: Daita
authors: D
authors: Nadano
authors: Asgerally T
authors: AT
authors: Fazleabas
authors: Tsutomu
authors: T
authors: Katsuyama
authors: Shiro
authors: S
authors: Nozawa
authors: Michiko N
authors: MN
authors: Fukuda
mesh_terms: D000328:Adult; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D006063:Chorionic Gonadotropin / Q000378:metabolism* / Q000494:pharmacology; D002824:Chorionic Villi; D010064:Embryo Implantation; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005187:Fallopian Tubes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005260:Female; D006801:Humans; D008875:Middle Aged; D011247:Pregnancy; D011274:Pregnancy, Tubal / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D014327:Trophoblasts
chemical_list: C112245:BYSL protein, human; D015815:Cell Adhesion Molecules; D006063:Chorionic Gonadotropin; D012333:RNA, Messenger; C093649:TRO protein, human; C093648:TROAP protein, human