APP and Alzheimer disease: While brains of patients with AD show upregulation of the VEGF suggesting an interaction of VEGF with APP processing (Burger et al., 2009), in vitro studies revealed that high concentrations of Aβ act as a VEGF antagonist, inhibiting VEGR receptor (VEGFR2) activation as well as VEGF-stimulated activation of eNOS in endothelium (Patel et al., 2010; Lamoke et al., 2015; Cho et al., 2017).