Fluid Dynamics Inside the Brain Barrier

Current Concept of Interstitial Flow, Glymphatic Flow, and Cerebrospinal Fluid Circulation in the Brain

Tsutomu Nakada, Ingrid Kwee

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The discovery of the water specific channel, aquaporin, and abundant expression of its isoform, aquaporin-4 (AQP-4), on astrocyte endfeet brought about significant advancements in the understanding of brain fluid dynamics. The brain is protected by barriers preventing free access of systemic fluid. The same barrier system, however, also isolates brain interstitial fluid from the hydro-dynamic effect of the systemic circulation. The systolic force of the heart, an essential factor for proper systemic interstitial fluid circulation, cannot be propagated to the interstitial fluid compartment of the brain. Without a proper alternative mechanism, brain interstitial fluid would stay stagnant. Water influx into the peri-capillary Virchow-Robin space (VRS) through the astrocyte AQP-4 system compensates for this hydrodynamic shortage essential for interstitial flow, introducing the condition virtually identical to systemic circulation, which by virtue of its fenestrated capillaries creates appropriate interstitial fluid motion. Interstitial flow in peri-arterial VRS constitutes an essential part of the clearance system for β-amyloid, whereas interstitial flow in peri-venous VRS creates bulk interstitial fluid flow, which, together with the choroid plexus, creates the necessary ventricular cerebrospinal fluid (CSF) volume for proper CSF circulation.

Original languageEnglish (US)
JournalNeuroscientist
DOIs
StateAccepted/In press - May 1 2018

Fingerprint

Extracellular Fluid
Hydrodynamics
Cerebrospinal Fluid
Songbirds
Brain
Aquaporin 4
Aquaporins
Astrocytes
Choroid Plexus
Amyloid
Protein Isoforms
Water

Keywords

  • AQP-4
  • aquaporin
  • choroid plexus
  • tight junction
  • Virchow-Robin space

ASJC Scopus subject areas

  • Neuroscience(all)
  • Clinical Neurology

Cite this

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