How Do Meningeal Lymphatic Vessels Drain the CNS?

The many interactions between the nervous and the immune systems, which are active in both physiological and pathological states, have recently become more clearly delineated with the discovery of a meningeal lymphatic system capable of carrying fluid, immune cells, and macromolecules from the central nervous system (CNS) to the draining deep cervical lymph nodes. However, the exact localization of the meningeal lymphatic vasculature and the path of drainage from the cerebrospinal fluid (CSF) to the lymphatics remain poorly understood. Here, we discuss the potential differences between peripheral and CNS lymphatic vessels and examine the purported mechanisms of CNS lymphatic drainage, along with how these may fit into established patterns of CSF flow.

TrendsFunctional classic lymphatic vessels exist in the dura, and can function to drain fluid and immune cells from the meninges, parenchyma, and CSF.The meningeal lymphatic system is necessary for the efficient clearance of brain ISF, and may be a common pathway for removal of wastes initially cleared from brain parenchyma through the glymphatic system of CSF–interstitial fluid (ISF) exchange.The precise location of meningeal lymphatic vessels within the layers of the meninges needs to be further investigated.The hemodynamics of the flow and access of the CSF to meningeal lymphatic vessels are still poorly understood.