Aquaporin‐4 facilitates reabsorption of excess fluid in vasogenic brain edema

Aquaporin-4 (AQP4) is the major water channel in the brain, expressed predominantly in astroglial cell membranes. Initial studies in AQP4-deficient mice showed reduced cellular brain edema following water intoxication and ischemic stroke. We hypothesized that AQP4 deletion would have the opposite effect (increased brain swelling) in vasogenic (noncellular) edema because of impaired removal of excess brain water through glial limitans and ependymal barriers. In support of this hypothesis, we found higher intracranial pressure (ICP, 52+/-6 vs. 26+/-3 cm H2O) and brain water content (81.2+/-0.1 vs. 80.4+/-0.1%) in AQP4-deficient mice after continuous intraparenchymal fluid infusion. In a freeze-injury model of…

• FF
  Foundation for the National Institutes of Health

  Awards: DK35124, HL59198, EB00415, EY13574, HL73856
• CF
  Cystic Fibrosis Foundation
• WT
  Wellcome Trust
• CF
  Cystic Fibrosis Trust
• NI
  National Institutes of Health