ACE and Alzheimer disease: Examining direct measures of ACE (such as serum or CSF ACE) in relation to CSF AD biomarkers might therefore be more clinically meaningful – especially since the widely prescribed antihypertensive ACE-inhibitors strongly inhibit ACE activity [16], thereby possibly not only reducing the unfavorable angiotensin (ANG)I to ANGII conversion, but also the favorable Aβ degradation.