Functional roles of lymphatics in health and disease

The mammalian lymphatic vasculature is a blind-ended network of thin-walled capillaries and larger collecting vessels covered by a continuous layer of endothelial cells that provides a unidirectional route to the return of filtered arterial and tissue metabolites toward the venous circulation. Its crucial roles in tissue fluid homeostasis, immune surveillance, and dietary fat absorption in the gastrointestinal organs have been well documented. The main symptomatic pathological consequences traditionally associated with lymphatic dysfunction are primary and secondary lymphedema; however, work in the last few years have greatly expanded our current understanding about the functional roles of lymphatics in health and disease. A variety of medical conditions such as obesity, cardiovascular disease, glaucoma, and neurological disorders have now been associated with a defective lymphatic vasculature. Here, we review some of those novel findings.