NGF and Alzheimer disease: In addition to the BDNF/TrkB system, to improve the low bioavailability and its BBB impermeability when using the NGF/TrkA system, the effects of ENT-A013, which is one of the NGF mimetics and a selective activator of TrkA, were examined and confirmed its neuroprotective and anti-Aβ function as a potential therapeutic candidate against AD [14].