In the last few years, it has been proposed that a deficit of neurotrophic factors such as NGF and TGF-β1 can contribute to the pathogenesis of AD-related cognitive decline, and a strong neurobiological link exists in the AD brain between an early pro-inflammatory process and a deficit of TGF-β1 (Iulita et al., 2016b; Caraci et al., 2017). Here, NGF is linked to Alzheimer disease.