title: Investigating the effect of excess caffeine exposure on placental angiogenesis using chicken 'functional' placental blood vessel network.
abstract: It is now known that over-consumption of caffeine by pregnant mothers could have detrimental effects on normal fetal development. However, it remains obscure how caffeine's harmful effect impacts directly or indirectly on the developing embryo/fetus through damaging placenta development. In this study, we demonstrated the morphological similarities between the yolk sac and chorioallantoic membranes (CAM) of chick embryos and the villi of the mammalian placenta. Using the chick yolk sac and the CAM as a model, we found that 5-15 µmol per egg of caffeine exposure inhibited angiogenesis. Under the same condition, cell proliferation in extraembryonic mesoderm was reduced while apoptosis was enhanced. Semi-quantitative RT-PCR analysis revealed that caffeine treatment down-regulated VEGF, VEGFR2, PIGF, IGF2 and NRP1 expression, but up-regulated Ang1 and Ang2 expression. We performed in situ hybridization to show VE-cadherin expression and as to demonstrate the blood vessels in the CAM and yolk sac membranes. This distribution of the VE-cadherin(+) blood vessels was determined to be reduced after caffeine treatment. Furthermore, MDA activity was induced after caffeine exposure, but GSH-PX activity was inhibited after caffeine exposure; SOD activity was unchanged as compared with the control. In summary, our results suggest that caffeine exposure could negatively impact on angiogenesis in the chick yolk sac and CAM by targeting angiogenesis-related genes. Some of these genes are also involved in regulating excess ROS generation. The results implied that the negative impact of caffeine on fetal development was partly attributed to impaired placental angiogenesis.
authors.affiliation: Department of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Institute of Fetal-Preterm Labor Medicine, Medical College of Jinan University, Guangzhou, 510632, China.
authors.forename: Zheng-Lai
authors.initials: ZL
authors.lastname: Ma
authors.affiliation: Department of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Institute of Fetal-Preterm Labor Medicine, Medical College of Jinan University, Guangzhou, 510632, China.
authors.forename: Guang
authors.initials: G
authors.lastname: Wang
authors.affiliation: Department of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Institute of Fetal-Preterm Labor Medicine, Medical College of Jinan University, Guangzhou, 510632, China.
authors.forename: Wen-Hui
authors.initials: WH
authors.lastname: Lu
authors.affiliation: Department of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Institute of Fetal-Preterm Labor Medicine, Medical College of Jinan University, Guangzhou, 510632, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Cheng
authors.affiliation: Division of Cell and Developmental Biology, University of Dundee, Dundee, DD1 5EH, UK.
authors.forename: Manli
authors.initials: M
authors.lastname: Chuai
authors.affiliation: Key Laboratory for Regenerative Medicine of the Ministry of Education, School of Biomedical Sciences, Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Kenneth Ka Ho
authors.initials: KK
authors.lastname: Lee
authors.affiliation: Department of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Institute of Fetal-Preterm Labor Medicine, Medical College of Jinan University, Guangzhou, 510632, China.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Yang
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000187:drug effects*; D002110:Caffeine / Q000633:toxicity*; D002645:Chickens; D005260:Female; D047109:Fetal Development / Q000187:drug effects*; D008322:Mammals / Q000254:growth & development*; D023421:Models, Animal; D010920:Placenta / Q000187:drug effects*; D011247:Pregnancy; D012098:Reproduction / Q000187:drug effects*; D015017:Yolk Sac / Q000187:drug effects*
chemical_list: D002110:Caffeine
keywords: ROS; angiogenesis; caffeine; chorioallantoic membrane; yolk sac membrane