title: The effects of homocysteine and folic acid on angiogenesis and VEGF expression during chicken vascular development.
abstract: Homocysteine (Hcy) has been implicated in the development of cardiovascular developmental defects. Additionally, in experimental studies, vasculotoxic properties of Hcy have been described. Although Hcy has been identified as a vascular pathogen, little is known about the direct effects Hcy exerts during early embryonic vascular development. Angiogenesis is a critical process involved in embryo survival and development. There are limited studies on the effects of Hcy on early embryonic vasculogenesis and angiogenesis. Folic acid (FA) is a B vitamin essential in embryo development, and FA supplementation may lead to reduced Hcy levels. Therefore, the purpose of our study was to explore the effects of Hcy and FA on early embryonic vascular development. Embryonic day (E) 3.5 chicken embryos were treated with a sham, Hcy or FA solution. We developed a computational program for systematic analysis of microscopic images obtained from the extra embryonic vascular beds. These results were combined with real-time PCR data on the expression of VEGF-A and its receptor in these vascular beds. Our data show that Hcy exposure inhibits early vascular development, displayed by a significant reduction of vessel area and altered composition of the vascular beds. Vascular beds of Hcy embryos for the greater part consisted of vessels of the smallest diameters, compared to middle size vessels in control and FA embryos. Hcy also reduced expression of VEGF-A and VEGFR-2. No significant effects of FA were found. We conclude that Hcy exposure causes impaired early extra embryonic vascular development, shown by altered composition of the vascular beds as well as reduced expression of VEGF-A and VEGFR-2. These effects of Hcy, and the consecutive cascade of events, may be involved in the development of cardiovascular developmental defects.
authors.affiliation: Erasmus MC, University Medical Center, Department of Obstetrics and Gynecology, Division of Obstetrics and Prenatal Medicine, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands. a.oosterbaan@erasmusmc.nl
authors.forename: Annelien M
authors.initials: AM
authors.lastname: Oosterbaan
authors.forename: Eric A P
authors.initials: EA
authors.lastname: Steegers
authors.forename: Nicolette T C
authors.initials: NT
authors.lastname: Ursem
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000187:drug effects* / Q000196:embryology / Q000378:metabolism; D002642:Chick Embryo; D015536:Down-Regulation; D005321:Extraembryonic Membranes / Q000098:blood supply* / Q000187:drug effects* / Q000378:metabolism; D005492:Folic Acid / Q000494:pharmacology*; D018507:Gene Expression Regulation, Developmental; D006710:Homocysteine / Q000633:toxicity*; D007091:Image Processing, Computer-Assisted; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D006710:Homocysteine; D005492:Folic Acid; D040301:Vascular Endothelial Growth Factor Receptor-2