Conclusions
The findings reported here raise the possibility that cerebral white matter may play a heretofore underappreciated role in the formation of cerebral edema following ischemia.
Results
Subcellular localization of Aqp4 was compared between cortical and white matter astrocytes in postmortem specimens of patients with focal ischemic stroke versus controls. Subcellular localization and expression of Aqp4 was examined in rats subjected to experimental stroke. Volumetric analysis was performed on the cortex and white matter of rats subjected to experimental stroke. Following cerebral ischemia, cortical astrocytes exhibited reduced perivascular Aqp4 and unchanged Aqp4 protein abundance. In contrast, white matter astrocytes exhibited increased perivascular and plasmalemmal Aqp4 and a 2.2- to 6.2-fold increase in Aqp4 isoform abundance. Ischemic white matter swelled by approximately 40 %, while cortex swelled by approximately 9 %. Conclusions: The findings reported here raise the possibility that cerebral white matter may play a heretofore underappreciated role in the formation of cerebral edema following ischemia.