Furthermore, Aβ-oligomers decrease astrocytes levels of TGF-β1, a cytokine that promotes the formation of synapses in the brain, further indicating new mechanisms involved in astrocytes-mediated synaptic dysfunction at the early stages of AD (Diniz et al., 2012, 2014; Araujo et al., 2016). This evidence concerns the gene TGFB1 and Alzheimer disease.