Morphological and functional analysis of CNS-associated lymphatics

The study of meningeal lymphatic vessels of the central nervous system (CNS) has recently gathered momentum, with several papers dissecting their role in draining solutes from cerebrospinal fluid and brain (Louveau et al., Nature 523(7560):337–341, 2015; Antila et al., J Exp Med 214(12):3645–3667, 2017; Aspelund et al., J Exp Med 212(7):991–999, 2015). Methodological capabilities, however, have been limited to few laboratories due to difficulties reproducibly visualizing these rare cell subsets in the meninges. To explore meningeal lymphatics fundamental role during homeostasis and how they may contribute to human pathology, the field has begun to require purification and characterization of lymphatic endothelial cells. Here, modern cell biological techniques involving a combination of histological, flow-cytometric, and functional drainage assays are applied to brain and spinal cord meninges and detailed stepwise procedures used for successful in vivo and ex vivo characterization of meningeal lymphatic vessels.