APOE and Alzheimer disease: Although the astrocyte-dependent lipidation of ApoE could contribute to the ability of glia to clear Aβ burden, this event does not seem to occur in ApoE4-carrying subjects [2], and defects in Aβ clearance have been detected in cerebrospinal fluid of >98% of LOAD cases [43], which may reflect defects in the endolysosomal/autophagy system in the early neuropathological stages of AD [44].