APOE and diabetes mellitus: Diabetes was produced by injecting five consecutive low doses of STZ (50 mg/kg/day intraperitoneal (IP)) in 8-week-old GRECKO (GR;fl/fl Tie1 Cre+) and Cre− littermate controls (GRfl/fl) and GR;fl/flTie1 Cre+/Apoe−/− (DKO) mice and Cre− littermates (GR;fl/flApoe−/−) (Fig. 2a).