Molecular and cellular mechanisms of lymphatic vascular maturation

• Lymphatic endothelial cells (LECs) originate from embryonic veins.
• LECs become lymphatic capillaries, lymphatic collecting vessels and valves.
• Perivascular cells surround collecting lymphatic vessels and propel lymph.
• Lymph is returned back to blood via two-pairs of lymphovenous valves.
• Platelets regulate blood and lymphatic vascular separation.

Lymphatic vasculature is necessary for maintaining fluid homeostasis in vertebrates. During embryogenesis lymphatic endothelial cells originate from the veins as a homogeneous population. These cells undergo a series of changes at the morphological and molecular levels to become mature lymphatic vasculature that consists of lymphatic capillaries, collecting lymphatic vessels and valves. In this article we summarize our current knowledge about these steps and highlight some black boxes that require further clarification.