Lymphangiogenesis in development and disease.

Lymphatic vessels are important for the maintenance of normal tissue fluid balance, for immune surveillance and adsorption of digested fats. In spite of their important functions in physiological as well as in various pathological conditions, including tumour metastasis, lymphoedema and inflammation, the lymphatic vessels have not received as much attention as the blood vessels, and the mechanisms regulating their development and growth have been poorly understood. However, recent studies using mouse genetic tools and primary lymphatic endothelial cell cultures have greatly increased our understanding of how the lymphatic endothelial cells differentiate, how lymphatic vessel growth is regulated and how the remodelling of the lymphatic vasculature into a functional vessel network consisting of capillaries and collecting vessels occurs. Furthermore, these studies have also provided mechanistic insights into the processes involved in pathological lymphangiogenesis.