INS and Alzheimer disease: Epidemiological studies have focused on the relationship between AD and the most common disorder of the insulin system, namely, “diabetes mellitus (DM)” (Goldstein, 2002; Biessels et al., 2006; Ghasemi et al., 2013; Dolan et al., 2020; Friman, 2020) and brain insulin resistance is considered a risk factor for AD and related neurodegenerative disorders (Rivera et al., 2005; Steen et al., 2005; Salkovic-Petrisic and Hoyer, 2007; Liu et al., 2011; Nuzzo et al., 2015; Rad et al., 2018; Akhtar and Sah, 2020; Kellar and Craft, 2020).