The lymphatics form a network of vessels with unidirectional transport from the tissue into the initial lymph channels, the lymph nodes, the thoracic ducts and into circulatory system. The lymphatics serve to transport proteins and lymphocytes and they play an important in diseases such as edema, ulcers, the spread of cancer or the survival of grafts.

A longstanding problem in physiology has been the understanding of the basic mechanisms for lymph fluid generation. Lymphatic pumping requires periodic expansion and compression provided by tissues surrounding the lymphatic channels. Lymphatics have valves in their lumen, but these are by themselves insufficient to provide transport from the tissue into the initial lymphatics. We have recently provided evidence that initial lymphatics have two valve systems, a primary valve system at the level of the initial lymphatic endothelium, and a secondary valve system that positioned in the lumen of the lymphatics. Lymph fluid transport requires the action of both valve systems in concert. Our research is designed to analyze the mechanisms of action of the primary lymphatic valves.