In the ischemic stroke mouse model, the presence of AQP4 was shown to aggravate post-ischemic cytotoxic edema as measured by post-ischemic hemispheric enlargement, while AQP4-null mice showed an opposite effect with an improved neurological outcome (Manley et al., 2000; Papadopoulos and Verkman, 2007). Here, AQP4 is linked to ischemic stroke.