APP and Alzheimer disease: Administration of a clinical dose of ACE inhibitor to human amyloid precursor protein transgenic mice was associated with increased brain amyloid deposition.4 In humans, patients with AD have lower Aβ42-to-Aβ40–converting activity compared with sera from age-matched healthy individuals.4 Our current findings support that ACE protects against AD, although further work is required to investigate whether this is attributable to reduced amyloid aggregation or other unrelated mechanisms.