AQP4 and Stroke: The AQP family contains 13 different members, of which the expression levels of AQP1, AQP4, and AQP9 in rodent models and humans are upregulated after stroke (Gonen and Walz, 2006; Ribeiro Mde et al., 2006; Yatsushige et al., 2007; Vella et al., 2015; Stokum et al., 2018).