Glymphatic Pathway: A Paravascular Pathway for Interstitial Solute Clearance

The brain is unique among virtually all somatic organs in its lack of a conventional lymphatic vasculature. In the periphery, the lymphatic circulation facilitates the clearance of extracellular proteins and excess fluid from the interstitium, a role critical to tissue homeostasis and function. Yet within the brain, despite its complex architecture and high metabolic activity and neural cells’ sensitivity to changes in the extracellular environment, no specialized organ-wide anatomic structure has yet been identified that facilitates the efficient lymphatic clearance of extracellular solutes and fluid from the brain parenchyma.