Remarkably, extensive evidence has indicated that ghrelin may alleviate AD-related pathology such as Aβ accumulation (Dhurandhar et al., 2013; Jeong et al., 2018), tau hyperphosphorylation (Kang et al., 2015), mitochondrial dysfunction (Chung et al., 2007), impaired adult neurogenesis (Moon et al., 2014), and neuroinflammation (Moon et al., 2011; Sibilia et al., 2012). Here, MAPT is linked to Alzheimer disease.