Role of Basic Fibroblast Growth Factor in the Formation of the Capillary 
Plexus in the Chick Embryo Chorioallantoic Membrane.  
An in situ Hybridization, Immunohistochemical and Ultrastructural Study. 
 
 
 
 
D. Ribatti, M. Bertossi, B. Nico, A. Vacca, R. Ria, A. Riva, L. Roncali , M. Presta
Institute of Anatomy, Histology and Embryology [D.R., M.B., B.N., L.R.] and Department of Biomedical Sciences and Human Oncology [A.V., R.R.], University of Bari; Department of Citomorphology, University of Cagliari [A.R]; Unit of General Pathology and Immunology, Department of Biomedical Sciences and Biotechnology, University of Brescia, Italy [M.P.].
 
 
 
 
 
 
SEM of chick embryo chorioallantoic membrane
 
Back to: Presta's lab

 

  

ABSTRACT 

The chick embryo chorioallantoic membrane (CAM) is supplied by an extensive capillary network. We have previously demonstrated that a Mr 16,000 basic fibroblast growth factor (FGF2)-like molecule is present in the CAM. At present, no data are available on the cellular source(s) of FGF2 in the CAM. 

In this work, CAM has been investigated by in situ hydridization with the aim to identify the source(s) of endogenous FGF2 during development. The immunohistochemical expression of fibronectin, laminin and type IV collagen in the CAM extracellular matrix (ECM) and the ultrastructural relationships between chorionic  epithelium and the underlying capillary plexus were also studied.  

Our findings strongly suggest that FGF2 regulates the development of the capillary plexus by two sequential steps. In an early paracrine phase, chorionic epithelial cells secrete FGF2, thus eliciting an angiogenic response in the undifferentiated mesodermal blood vessels. In response to this paracrine signalling, the newly formed endothelial cells move through a permissive ECM and migrate beneath the chorion. Here, they synthesize an autocrine supply of FGF2 necessary to further proliferate and differentiate, thus originating the capillary plexus. 
 

 J. Submicrosc. Cytol. Pathol. (1998) 30:127-136 
 
 
Back to: AIRC - Special Project Angiogenesis