Fig. 3

Anatomical pathways and barriers of the CNS as potential routes for extracellular vesicles. The figure shows theoretical vascular points of entrance for EVs and checkpoint barriers to the brain parenchyma that should be further examined. A The classical path that has been evaluated for EVs crossing from peripherical blood to the brain is through arterial flow and the BBB, comprised of endothelial cells, pericytes, and astrocytes [28, 30,31,32]. B The recently discovered meningeal lymphatic vessels expose a route to the CSF-brain barrier not yet explored and that EVs could exploit to access the brain parenchyma [85]. C A third entrance point is through the Blood-CSF barrier at the choroid plexus [84]. EVs: extracellular vesicles; BBB: blood brain barrier; CNS: Central Nervous System; CSF: cerebrospinal fluid