NGF and Alzheimer disease: The therapeutic potential of human NGF (hNGF) has already been tested for several neurodegenerative conditions, among which the prominent ones are AD (Jönhagen et al., 1998; Aloe et al., 2012), Parkinson’s disease (PD) (Olson et al., 1991; 1992), and traumatic brain injury (Holtzman et al., 1996).