Journal of Molecular Medicine

, Volume 96, Issue 5, pp 383–390 | Cite as

Brain drains: new insights into brain clearance pathways from lymphatic biology

  • Neil I. Bower
  • Benjamin M. Hogan


The lymphatic vasculature act as the drainage system for most of our tissues and organs, clearing interstitial fluid and waste and returning them to the blood circulation. This is not the case for the central nervous system (CNS), which is devoid of parenchymal lymphatic vessels. Nevertheless, the brain is responsible for 25% of the body’s metabolism and only compromises 2% of the body’s mass. This high metabolic load requires an efficient system to remove waste products and maintain homeostasis. Well-described mechanisms of waste clearance include phagocytic immune cell functions as well as perivascular fluid flow; however, the need for active drainage of waste from the brain is becoming increasingly appreciated. Recent developments in lymphatic vascular biology challenge the proposition that the brain lacks lymphatic drainage or an equivalent. In this review, we describe the roles of the glymphatic system (a key drainage mechanism in the absence of lymphatics), the recently characterized meningeal lymphatic vessels, and explore an enigmatic cell population found in zebrafish called mural lymphatic endothelial cells. These systems may play important individual and collective roles in draining and clearing wastes from the brain.


Lymphatic vascular system Tissue interstitial fluid Central nervous system 


Funding information

B.M.H. by an NHMRC/National Heart Foundation Career Development Fellowship (1083811). N.I.B. was supported in part by NHMRC Project grant (1079670).


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Division of Genomics of Development and Disease, Institute for Molecular BioscienceThe University of QueenslandSt LuciaAustralia

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