title: The fetomaternal interface in the placenta of three species of armadillos (Eutheria, Xenarthra, Dasypodidae).
abstract: BACKGROUND
  Placental characters vary among Xenarthra, one of four supraordinal clades of Eutheria. Armadillos are known for villous, haemochorial placentas similar to humans. Only the nine-banded armadillo has been well studied so far.
  
  
  METHODS
  Placentas of three species of armadillos were investigated by means of histology, immunohistochemistry including proliferation marker, and transmission and scanning electron microscopy.
  
  
  RESULTS
  The gross anatomy differed: Euphractus sexcinctus and Chaetophractus villosus had extended, zonary placentas, whereas Chaetophractus vellerosus had a disk. All taxa had complex villous areas within the maternal blood sinuses of the endometrium. Immunohistochemistry indicated the validity of former interpretations that the endothelium of the sinuses was largely intact. Tips of the villi and the columns entering the maternal tissue possessed trophoblast cell clusters with proliferation activity. Elsewhere, the feto-maternal barrier was syncytial haemochorial with fetal vessels near the surface.
  
  
  CONCLUSIONS
  Differences among armadillos occurred in regard to the extension of the placenta, whereas the fine structure was similar. Parallels to the human suggest that armadillos are likely to be useful animal models for human placentation.
authors.affiliation: Department of Surgery, Faculty of Veterinary Medicine, University of Sao Paulo, Av. Prof. Dr. Orlando Marques de Paiva, no. 87, Cidade Universitária, São Paulo, SPCEP 05508-000, Brazil.
authors.forename: Lorenna C
authors.initials: LC
authors.lastname: Rezende
authors.forename: Claudio G
authors.initials: CG
authors.lastname: Barbeito
authors.forename: Phelipe O
authors.initials: PO
authors.lastname: Favaron
authors.forename: Andrea
authors.initials: A
authors.lastname: Mess
authors.forename: Maria A
authors.initials: MA
authors.lastname: Miglino
mesh_terms: D000818:Animals; D000835:Animals, Wild / Q000033:anatomy & histology* / Q000378:metabolism; D001118:Argentina; D001135:Armadillos / Q000033:anatomy & histology* / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D001938:Brazil; D049109:Cell Proliferation; D049033:Chorioallantoic Membrane / Q000033:anatomy & histology / Q000166:cytology / Q000378:metabolism; D005260:Female; D007150:Immunohistochemistry; D010920:Placenta / Q000033:anatomy & histology* / Q000166:cytology / Q000378:metabolism; D010929:Placentation; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000378:metabolism; D013045:Species Specificity; D014327:Trophoblasts / Q000166:cytology / Q000378:metabolism; D004490:Xenarthra / Q000033:anatomy & histology / Q000378:metabolism
chemical_list: D015415:Biomarkers; D011257:Pregnancy Proteins