Waste Clearance in the Brain

Waste clearance (WC) is an essential process for brain homeostasis, which is required for the proper and healthy functioning of all cerebrovascular and parenchymal brain cells. This review features our current understanding of brain WC, both within and external to the brain parenchyma. We describe the interplay of the blood-brain barrier (BBB), interstitial fluid (ISF), and perivascular spaces within the brain parenchyma for brain WC directly into the blood and/or cerebrospinal fluid (CSF). We also discuss the relevant role of the CSF and its exit routes in mediating WC. Recent discoveries of the glymphatic system and meningeal lymphatic vessels, and their relevance to brain WC are highlighted. Controversies related to brain WC research and potential future directions are presented.

Automated summary

This review provides an overview of the importance of waste clearance in the brain and its mechanisms both within and outside the brain parenchyma. It focuses on the interplay of the blood-brain barrier, interstitial fluid, and perivascular spaces within the brain parenchyma for waste clearance, as well as the role of CSF and its exit routes. Recent discoveries of the glymphatic system and meningeal lymphatic vessels in brain waste clearance are emphasized.