Hum. Reprod. Advance Access published online on June 1, 2007
Human Reproduction, doi:10.1093/humrep/dem143
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The architecture of first trimester chorionic villous vascularization: a confocal laser scanning microscopical study
1 Department of Obstetrics and Gynaecology, Academic Medical Centre, University of Amsterdam, PO Box 22700, 1100 DE Amsterdam, The Netherlands 2 Department of Anatomy and Embryology, Academic Medical Centre, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands 3 Department of Pathology, Spaarne Ziekenhuis Hoofddorp, PO Box 770, 2130 AT Hoofddorp, The Netherlands 4 Department of Obstetrics and Gynaecology, Spaarne Ziekenhuis Hoofddorp, PO Box 770, 2130 AT Hoofddorp, The Netherlands
5 Correspondence address. Tel: +31 20 566 6429, Fax: +31 20 696 3489. E-mail: b.a.lisman{at}amc.uva.nl
BACKGROUND: The aim of this study was to investigate normal chorionic villous vascularization using CD31 immunofluorescence and confocal laser scanning microscopy (CLSM) to elucidate the spatial arrangement in terms of connections between vessels and cords and their branching patterns compared to deficient chorionic villous vascularization in complicated pregnancies.
METHODS: A descriptive morphologic study using CLSM after CD31 immunofluorescence staining of placental biopsies from normal pregnancies (n = 20), complete hydatidiform molar pregnancies (CHMs; n = 3) and empty sacs (n = 3), with a well documented gestational age (GA).
RESULTS: In this three-dimensional study, first trimester chorionic villi were occupied by a complex network of mainly cords with redundant connections as early as 5+5 weeks GA. With increasing GA cords transform into vessels. From about 9 weeks GA onwards, vascular development is characterized by the presence of two large vessels located centrally and surrounded by and connected to a capillary network. In first trimester CHM and empty sacs, we observed a primitive network of mainly cords.
CONCLUSIONS: This first visualization of the spatio-temporal patterns of blood vessel formation in placental villi is characterized by the development of the vasculosyncytial membrane from a complex network of cords and can be regarded as the placental development before it becomes functional at the end of organogenesis.
Key words: first trimester pregnancy/CD31/vasculogenesis/chorion villus/confocal laser scanning microscopy
Submitted on February 1, 2007; resubmitted on April 22, 2007; accepted on May 1, 2007.