Neurocritical Care

, Volume 13, Issue 1, pp 123–131

Na+–K+–2Cl Cotransport Inhibitor Attenuates Cerebral Edema Following Experimental Stroke via the Perivascular Pool of Aquaporin-4

  • Elton R. Migliati
  • Mahmood Amiry-Moghaddam
  • Stanley C. Froehner
  • Marvin E. Adams
  • Ole Petter Ottersen
  • Anish Bhardwaj
Translational Research

DOI: 10.1007/s12028-010-9376-8

Cite this article as:
Migliati, E.R., Amiry-Moghaddam, M., Froehner, S.C. et al. Neurocrit Care (2010) 13: 123. doi:10.1007/s12028-010-9376-8

Abstract

Introduction

The Na+–K+–2Cl cotransporter localized in the brain vascular endothelium has been shown to be important in the evolution of cerebral edema following experimental stroke. Previous in vivo studies have demonstrated that bumetanide, a selective Na+–K+–2Cl cotransport inhibitor, attenuates ischemia-evoked cerebral edema. Recently, bumetanide has been shown to also inhibit water permeability via aquaporin-4 (AQP4) expressed in Xenopus laevis oocytes. We tested the hypothesis that the perivascular pool of AQP4 plays a significant role in the anti-edema effect of bumetanide by utilizing wild-type (WT) mice as well as mice with targeted disruption of α-syntrophin (α-Syn−/−) that lack the perivascular pool of AQP4.

Methods

Isoflurane-anesthetized adult male WT C57Bl6 and α-Syn−/− mice were subjected to 90 min middle cerebral artery occlusion (MCAO) followed by 24 or 48 h of reperfusion. Adequacy of MCAO and reperfusion was monitored with laser-Doppler flowmetry over the ipsilateral parietal cortex. Infarct volume (tetrazolium staining), cerebral edema (wet-to-dry ratios), and AQP4 protein expression (immunoblotting) were determined in different treatment groups in separate sets of experiments.

Results

Bumetanide significantly attenuated infarct volume and decreased ipsilateral hemispheric water content in WT mice compared to vehicle treatment. In α-Syn−/− mice, bumetanide treatment had no effect on infarct volume or ischemia-evoked cerebral edema. Bumetanide-treated WT mice had a significant attenuation of AQP4 protein expression at 48 h post-MCAO compared to vehicle-treated WT mice.

Conclusions

These data suggest that bumetanide exerts its neuroprotective and anti-edema effects partly via blockade of the perivascular pool of AQP4 and may have therapeutic potential for ischemic stroke in the clinical setting.

Keywords

AquaporinsStrokeFocal cerebral ischemiaInfarctCerebral edemaBumetanide

Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  • Elton R. Migliati
    • 1
  • Mahmood Amiry-Moghaddam
    • 2
  • Stanley C. Froehner
    • 3
  • Marvin E. Adams
    • 3
  • Ole Petter Ottersen
    • 2
  • Anish Bhardwaj
    • 1
    • 4
    • 5
    • 6
  1. 1.Department of NeurologyOregon Health & Science UniversityPortlandUSA
  2. 2.Center for Molecular Biology and Neuroscience and Department of Anatomy, Institute of Basic Medical SciencesUniversity of OsloOsloNorway
  3. 3.Department of Physiology and BiophysicsUniversity of WashingtonSeattleUSA
  4. 4.Department of Anesthesiology and Peri-Operative MedicineOregon Health Science UniversityPortlandUSA
  5. 5.Neurological SurgeryOregon Health Science UniversityPortlandUSA
  6. 6.Department of NeurologyTufts University School of Medicine, Tufts Medical CenterBostonUSA