Structure and Function Study on Lymphatic System in Central Nervous System and Peripheral Organs

Lymphatic circulation is the second circulatory system of vertebrates besides cardiovascular system. As a unidirectional transportation system, it starts from lymphatic capillary with blind end in interstitial spaces, which are connected with larger collecting lymphatic vessels and finally returned into blood vasculature via lymphatic duct. Lymphatic system plays critical roles in human health and diseases, including regulation of body fluid homeostasis, immune surveillance, lipid metabolism, lymphedema and tumor metastasis. Central nervous system (CNS) was thought to be devoid of lymphatic vasculature for a long time. Though several years ago, glymphatic system was also discovered to play important roles in waste clearance in brain tissues, which functions like lymphatic system. Classical lymphatic structures were lacking until recent works unveiled the structure and function of meningeal lymphatic vessels (MLVs) primarily. This has also increased much more interest in lymphatic research on CNS. Lymphatic vasculature has been shown to be involved in CNS inflammation disorders and neurological diseases with growing evidence. Therefore, this review aims to discuss recent advances in our understating of lymphatic vasculature in CNS, and the roles of lymphatic system in human diseases.