AQP4 KO mice exhibit a 25–60% decrease in glymphatic CSF tracer influx (Mestre et al., 2018a; Hablitz et al., 2020; Zhang et al., 2019), and acute pharmacological blockade of AQP4 inhibits glymphatic transport using TGN-020 inhibitor (Huber et al., 2009; Harrison et al., 2020; Takano and Yamada, 2020), reducing severity of brain edema and lesion volume after ischemic injury (Igarashi et al., 2011; Sun et al., 2022). Here, AQP4 is linked to brain edema.