Abstract:
Vascular development during embryogenesis is tightly regulated and occurs at two
distinct locations - extra-embryonic yolk sac and embryo proper (Coultas et al., 2005).
The endothelial precursors at both locations coalesce to form the primary capillary
plexus. This primitive vasculature then undergoes remodelling to form a hierarchical
vascular tree comprising of veins, arteries and capillaries (Carmeliet and Jain, 2011;
Coultas et al., 2005). The intricate network of vessels forms as an outcome of the
complex interplay of highly regulated gene networks. Epigenetic mechanisms such as
hemodynamics also play an important role in establishing the final vascular architecture
(Jones et al., 2006). The endothelium remains quiescent after birth but gets reactivated in
certain situations like during wound healing or in the female reproductive system to
establish a new vessel network in a well-controlled manner (Papetti and Herman, 2002).
In contrast, the new vessels formed as a result of aberrant activation of endothelium
contribute to several diseases such as ischemia, retinopathies and tumors (Carmeliet,
2003; Chung et al., 2010). Understanding the complex molecular signals that establish
and maintain a normal vascular network may aid in designing effective pro- or antiangiogenic therapies to overcome several diseases.
