EDN1 and Alzheimer disease: Microvessels have been isolated from human AD brain and such investigations have shown an increase in nitric oxide synthase (Dorheim et al., 1994), an increase in inflammatory cytokines such as interleukin-1β or TNFα (Grammas and Ovase, 2001), and an increase in vasoactive peptides such as endothelin (ET)-1 in AD brain microvessels (Luo and Grammas, 2010).