Are human placental bed giant cells merely aggregates of small mononuclear trophoblast cells? An ultrastructural and immunocytochemical study

• Published in: Human reproduction (Oxford) Vol. 14; no. 2; pp. 496 - 504
• Main Authors: Al-Lamki, R.S., Skepper, J.N., Burton, G.J.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01-02-1999; Oxford Publishing Limited (England)
• Subjects: Biological and medical sciences; cell aggregate; Cell Aggregation - physiology; Cell Nucleus - ultrastructure; Connexin 43 - metabolism; Connexins - metabolism; Embryology: invertebrates and vertebrates. Teratology; Female; Fetal membranes; Fundamental and applied biological sciences. Psychology; Gap Junction beta-1 Protein; General aspects. Development. Fetal membranes; Giant Cells - cytology; Giant Cells - metabolism; Giant Cells - ultrastructure; human; Humans; immunocytochemistry; Immunohistochemistry; Microscopy, Confocal; Microscopy, Electron; Placenta - cytology; Placenta - metabolism; Placenta - ultrastructure; placental bed giant cell; Pregnancy; Pregnancy Proteins - metabolism; Pregnancy Trimester, First; Trophoblasts - physiology; Trophoblasts - ultrastructure; ultrastructure; immunocytochemistry; cell aggregate; placental bed giant cell; ultrastructure; human; Aggregation; Human; Trophoblaste; Mononuclear cell; Placenta; Fetal membrane; Immunocytochemistry; Ultrastructure; Giant cell
• ISSN: 0268-1161; 1460-2350
• DOI: 10.1093/humrep/14.2.496

The ultrastructure of placental bed giant cells in early human pregnancies of 7–12 weeks gestational age is described. Their nature and function was further characterized by confocal immunofluorescence microscopy of paraffin sections labelled for cytokeratin, gap junction connexins (CX) 32 or 43, and placental hormones, α-human chorionic gonadotrophin (α-HCG) and human placental lactogen (HPL). Placental bed giant cells were observed with two phenotypes; as single large trophoblast cells containing one or more nuclear profiles in a voluminous cytoplasm, and as cell aggregates comprising mononuclear trophoblast cells in close apposition separated by narrow intercellular spaces. Cells within the aggregates are attached to one another by desmosomes, and also possess gap junctions as shown by immunolabelling for CX32 and CX43. By contrast, gap junctions were absent in the true multinucleated giant cells. Organelles present within the cytoplasm of the giant cells and their immunoreactivity for HPL and α-HCG suggest protein synthesis.