LEP and Alzheimer disease: Accumulating in vivo and in vitro studies have suggested that leptin has notable effects on neuroprotection (Bahor et al., 2017; Begley & Ellis, 2012; Fernandez‐Martos et al., 2017; Liu et al., 2020; Marwarha et al., 2010) as well as on improving learning and cognitive function in Alzheimer ́s disease (AD) (Farr et al., 2006; Sato et al., 2011; Searcy et al., 2012).