Loss of aquaporin-4 results in glymphatic system dysfunction via brain-wide interstitial fluid stagnation

  1. Ryszard Stefan Gomolka
  2. Lauren M Hablitz
  3. Humberto Payne Mestre
  4. Michael Giannetto
  5. Ting Du
  6. Natalie Linea Hauglund
  7. Lulu Xie
  8. Weiguo Peng
  9. Paula Melero Martinez
  10. Maiken Nedergaard  Is a corresponding author
  11. Yuki Mori  Is a corresponding author
  1. University of Copenhagen, Denmark
  2. University of Rochester Medical Center, United States
  3. University of Pennsylvania, United States

Abstract

The glymphatic system is a fluid transport network of cerebrospinal fluid (CSF) entering the brain along arterial perivascular spaces, exchanging with interstitial fluid (ISF), ultimately establishing directional clearance of interstitial solutes. CSF transport is facilitated by the expression of aquaporin-4 (AQP4) water channels on the perivascular endfeet of astrocytes. Mice with genetic deletion of AQP4 (AQP4 KO) exhibit abnormalities in the brain structure and molecular water transport. Yet, no studies have systematically examined how these abnormalities in structure and water transport correlate with glymphatic function. Here we used high-resolution 3D magnetic resonance (MR) non-contrast cisternography, diffusion-weighted MR imaging (MR-DWI) along with intravoxel-incoherent motion (IVIM) DWI, while evaluating glymphatic function using a standard dynamic contrast-enhanced MR imaging to better understand how water transport and glymphatic function is disrupted after genetic deletion of AQP4. AQP4 KO mice had larger interstitial spaces and total brain volumes resulting in higher water content and reduced CSF space volumes, despite similar CSF production rates and vascular density compared to wildtype mice. The larger interstitial fluid volume likely resulted in increased slow but not fast MR diffusion measures and coincided with reduced glymphatic influx. This markedly altered brain fluid transport in AQP4 KO mice may result from a reduction in glymphatic clearance, leading to enlargement and stagnation of fluid in the interstitial space. Overall, diffusion MR is a useful tool to evaluate glymphatic function and may serve as valuable translational biomarker to study glymphatics in human disease.

Data availability

Entire data from the paper is available in the .xls data file attached. The attached data file is subdivided into separate sheets, each for a single experiment and accompanied with respective heading and descriptions, and provides the possibility of replicating all figures and statistics. A summary of data is presented in the tables and figures within the paper.A detailed description of an author algorithm for CSF space segmentation from 3D-CISS images, as well as DWI analysis, is provided in the Materials and Methods section (page 14 onward). Submission of the CSF space segmentation code in Matlab will be performed during the submission of a separate technical paper and will include a supplementary evaluation of this authorship algorithm using a large data set. A preliminary evaluation of the algorithm was presented during ESMRMB 2021 conference: Gomolka RS, Nedergaard M, Mori Y. CSF space volumetry using 3D-CISS in Aqp4-deficient mice - quantitative analysis and technical advances. ESMRMB 2021 Online 38th Annual Scientific Meeting 7-9 October 2021. Book of Abstracts ESMRMB 2021. Magnetic Resonance Materials in Physics, Biology, and Medicine; 34: S95-6. [Poster, abstract]. Therefore, publishing the code in Github (or else) will take place parallel to submitting a separate technical report on the algorithm.

Article and author information

Author details

  1. Ryszard Stefan Gomolka

    Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
    Competing interests
    The authors declare that no competing interests exist.
  2. Lauren M Hablitz

    Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-6159-7742
  3. Humberto Payne Mestre

    Department of Neurology, University of Pennsylvania, Philadelphia, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-5876-5397
  4. Michael Giannetto

    Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-4338-8709
  5. Ting Du

    Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Natalie Linea Hauglund

    Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-2198-6329
  7. Lulu Xie

    Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States
    Competing interests
    The authors declare that no competing interests exist.
  8. Weiguo Peng

    Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States
    Competing interests
    The authors declare that no competing interests exist.
  9. Paula Melero Martinez

    Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
    Competing interests
    The authors declare that no competing interests exist.
  10. Maiken Nedergaard

    Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
    For correspondence
    nedergaard@sund.ku.dk
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-6502-6031
  11. Yuki Mori

    Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
    For correspondence
    yuki.mori@sund.ku.dk
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-4208-0005

Funding

Lundbeckfonden (R386--2021--165)

  • Maiken Nedergaard

Novo Nordisk Fonden (NNF20OC0066419)

  • Maiken Nedergaard

National Institutes of Health (R01AT011439)

  • Maiken Nedergaard

National Institutes of Health (U19NS128613)

  • Maiken Nedergaard

Army Research Office (W911NF1910280)

  • Maiken Nedergaard

Human Frontier Science Program (RGP0036)

  • Maiken Nedergaard

Simons Foundation (811237)

  • Maiken Nedergaard

Adelson Family Foundation

  • Maiken Nedergaard

The views and conclusions contained in this article are solely those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the National Institutes of Health, the Army Research Office, or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein. The funding agencies have taken no part on the design of the study, data collection, analysis, interpretation, or in writing of the manuscript.

Ethics

Animal experimentation: All experiments were performed based on approval received from both the Danish Animal Experiments Inspectorate (License number: 2020-15-0201-00581) and the University of Rochester Medical Center Committee on Animal Resources (UCAR, Protocol 2011-023).

Copyright

© 2023, Gomolka et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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  1. Ryszard Stefan Gomolka
  2. Lauren M Hablitz
  3. Humberto Payne Mestre
  4. Michael Giannetto
  5. Ting Du
  6. Natalie Linea Hauglund
  7. Lulu Xie
  8. Weiguo Peng
  9. Paula Melero Martinez
  10. Maiken Nedergaard
  11. Yuki Mori
(2023)
Loss of aquaporin-4 results in glymphatic system dysfunction via brain-wide interstitial fluid stagnation
eLife 12:e82232.
https://doi.org/10.7554/eLife.82232

Share this article

https://doi.org/10.7554/eLife.82232

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