In old ApoE−/− mice, endothelial dysfunction occurs but was strictly correlated with the development and size of plaques, with plaque‐free regions exhibiting normal behaviour (Bonthu et al. 1997; Deckert et al. 1999; Yaghoubi et al. 2000; Crauwels et al. 2003). Here, APOE is linked to endothelial dysfunction.