VEGF and vascular fusion: implications for normal and pathological vessels

Area of Science:

• Developmental biology
• Vascular biology
• Embryology

Background:

• The avian embryo provides a suitable model for studying blood vessel morphogenesis, particularly de novo blood vessel formation (vasculogenesis).
• Understanding the cellular and molecular regulation of vasculogenesis is crucial for developmental and vascular biology.

Purpose of the Study:

• To investigate the role of vascular endothelial growth factor (VEGF) in regulating vasculogenesis using a whole-embryo bioassay.
• To characterize the vascular malformations induced by VEGF during embryonic development.

Main Methods:

• Development of a bioassay employing intact avian embryos to study vasculogenesis.
• Microinjection of recombinant vascular endothelial growth factor 165 (VEGF165) into avian embryos.
• Observation and analysis of resulting blood vessel morphology.

Main Results:

• Vascular endothelial growth factor (VEGF) induces a vascular malformation termed "hyperfusion" in avian embryos.
• Microinjection of VEGF165 transformed discrete embryonic blood vessels into enlarged endothelial sinuses.
• Exaggerated VEGF165 effects resulted in a single, enormous vascular sinus, resembling pathologies seen in neovascular diseases.

Conclusions:

• VEGF plays a significant role in regulating blood vessel morphogenesis during embryonic development.
• VEGF-induced hyperfusion represents a model for studying pathological vascular development.
• The avian whole-embryo assay is effective for dissecting molecular mechanisms of vasculogenesis and vascular malformations.