title: Presence of erythrocytes in the villous trophoblast cell layer of normal first trimester and term human placentae.
abstract: Light and electron microscopic examination of first-trimester and term human placental tissues were performed to identify erythrocytes containing hemoglobin in the villous trophoblast cell layer. Erythrocytes were not identified in chorionic villous epithelium at week 7 of gestation. These cells first appeared in the villous cytotrophoblast at week 8, and continued to be present in the villous cytotrophoblast until week 9, as shown by benzidine staining. At week 12 gestation, a cluster of erythrocytes was present in a villous syncytial sprout. At 40 and 41 weeks gestation, erythrocytes were located in the villous cytotrophoblast cell layer. Electron microscopic observations focused on the cytoplasm of villous cytotrophoblast at week 8, the syncytial sprout at week 12 and the cytotrophoblast cell layer at term, confirmed the presence of erythrocytes at an extravascular location, as observed by light microscopy.
authors: Laboratory of Electron Microscopy, Fujita Health University, Toyoake, Aichi, Japan. g-niimi@fujita-hu.ac.jp
authors: Gen
authors: G
authors: Niimi
authors: Kiyoshi
authors: K
authors: Hasegawa
authors: Nobuteru
authors: N
authors: Usuda
authors: Masanori
authors: M
authors: Shinzato
authors: Jaime
authors: J
authors: Pereda
authors: Yoichi
authors: Y
authors: Nagamura
mesh_terms: D001808:Blood Vessels / Q000196:embryology / Q000502:physiology / Q000648:ultrastructure; D002454:Cell Differentiation / Q000502:physiology; D002585:Cesarean Section; D002824:Chorionic Villi / Q000098:blood supply* / Q000502:physiology / Q000648:ultrastructure*; D004847:Epithelial Cells / Q000502:physiology / Q000648:ultrastructure; D004912:Erythrocytes / Q000502:physiology / Q000648:ultrastructure*; D005260:Female; D006412:Hematopoietic Stem Cells / Q000502:physiology / Q000648:ultrastructure; D006801:Humans; D008648:Mesoderm / Q000502:physiology / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D018919:Neovascularization, Physiologic / Q000502:physiology; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D013997:Time Factors; D014327:Trophoblasts / Q000502:physiology / Q000648:ultrastructure*