MAS1 and Alzheimer disease: Lower ACE-2 activity in AD may therefore promote the early deposition of Aβ43 and prevent downstream cleavage of Aβ42 by ACE-1.Together, these data suggest a putative protective role of the ACE-2/Ang (1–7)/Mas pathway, not only against the development of pathology but also against the decline in cognitive function, that is lost in AD.