Different studies have showed an association between this ApoE isoform and increased levels of neurotoxic and inflammatory cytokines, such as tumor necrosis factor α (TNFα), Interleukin-6 (IL-6), Interleukin-1β (IL-1β) and nitric oxide released by microglia and astrocytes, in different models of AD [24]. Here, APOE is linked to Alzheimer disease.