AQP4 and sleep apnea syndrome: Low AQP4 [Aquaporin Q4] expression, migration of AQP4 from the astrocytic end feet, attenuated pulsations of arterial vessels, accumulation of Aβ in the glymphatic space, and sleep apnea are some of underlying aberrations in the AD that are implicated to perturb the smooth sailing of GFAP emigration out of the brain circulation [43,172].