AQP4 and Stroke: The contribution of AQP4 varies greatly depending on time post-injury, brain region, amongst others leading to apparently contradictory results on edema, lesion size and outcome in AQP4 KO mice after stroke (Manley et al., 2000; Yao et al., 2008; Zeng et al., 2012; Hirt et al., 2017).