APP and endothelial dysfunction: Several studies of transgenic mice over expressing APP have demonstrated oxidative damage of CECs, up regulation of superoxide dismutase (SOD) around brain micro vessels, and significant impairment of the cerebrovascular functions.43–45 At the same time, endothelial dysfunctions were not observed in mice over expressing both APP and SOD-1 or in a case when SOD was directly applied to the cerebral cortex of the APP mice.44In vitro, treatment of CECs with Aβ increased free radical production and this effect was attenuated by free radical scavengers.43,46