GDNF and Alzheimer disease: In another study, Goetzl et al. showed that ADEs in plasma carry elevated levels of BACE1 and soluble amyloid precursor protein-β (sAPPβ), along with reduced levels of glial cell line-derived neurotrophic factor (GDNF) in AD patients, highlighting the potential of astrocytic EV cargo as accessible biomarkers for detecting and monitoring AD [77].