In vascular cognitive impairment and dementia (often coexisting with AD, the second leading cause of dementia after AD) mouse models, Sudduth et al. (2017) demonstrated the destruction of astrocyte terminal protrusions and a decrease in DP71, AQP4, and Kir4.1 localization along with neuroinflammation and cognitive dysfunction. Here, AQP4 is linked to Alzheimer disease.