INS and type 1 diabetes mellitus: The therapeutic effects of central leptin gene therapy have been reported in insulin-deficient diabetes and in obesity animal models, such as ob/ob, diet-induced obese mice, insulin-deficient type 1 diabetes mice, and insulin-dependent diabetes animals (Akita mice) (Dube et al., 2002; Ueno et al., 2004, 2006; Yu et al., 2008; Kalra, 2009; Kojima et al., 2009; Naito et al., 2011).