In the early stage of AD pathology, microglia also release insulin-degrading enzyme (IDE), proteins of the matrix metalloproteinase 9 (MMP9), plasminogen and neprilysin, which are involved in Aβ degradation and induce Aβ clearance (Gao et al., 2018; Corraliza-Gómez et al., 2022). Here, MMP9 is linked to Alzheimer disease.