Embryonic Vascular Plasticity
Ahmet Çağrı Aykan, Banu Şahi̇n Yıldız
Keywords: Embryo, vascular, development
The circulatory system is a complex system containing the heart and vessels. This system, originating from extraembryonic mesoderm, is the first functioning system of the embryo. The formation of the angioblast and primitive placental circulation starts at the beginning of the third week. Plasticity is defined as the ability of a mature cell to differentiate into different cell types. Haematopoietic stem cells can transform into neural, heart muscle, skeletal muscle and liver cells, while the bone marrow stromal cells can transform into heart and skeletal muscle cells. The identification of vessels as artery, venous or capillary is closely related to remodelling. Arteries express ephrin-B2 and D114, while veins express ephrin-B4 and neuropilin-2. With the guidance of these genes, the identification of arteries and veins has started. Besides genes, physical factors, including hemodynamic and cardiac output regulations, affect vessel branching. Flow-mediated vascular plasticity is a crucial link between the genetic and epigenetic factors. The arterial and venous differentiations are controlled by hemodynamic factors. In conclusion, blood flow is important for the formation of a vascular tree and activates arterial markers, including ephrin-B2 and neuropilin-1.