ACE activity in CSF of patients with mild cognitive impairment and Alzheimer disease

There is increasing evidence of angiotensin-converting enzyme (ACE) in the development of Alzheimer disease (AD).1-3 However, little is known about the ACE activity in the CNS in living patients with AD. We therefore measured ACE activity in CSF in patients with mild cognitive impairment (MCI) and mild to moderate AD and compared the values with those of age-matched healthy control subjects. We also examined whether treatment with a brain-penetrating ACE inhibitor3 can alter CSF ACE activity in patients with mild to moderate AD. We registered 90 patients (mean age 72.6 ± 1.8 [SE] years) who had undergone evaluations for memory disturbance at the Tohoku University Hospital Outpatient Clinic on Dementia in January 2003. Clinical assessments by geriatricians and neuropsychological examinations, including Mini-Mental State Examination (MMSE) and Wechsler Memory Scale–Revised, were performed for all subjects, as described previously.4 Our established criteria4 based on the current consensus5 were used for a diagnosis of progressive MCI and AD-converted MCI. In detail, 28 individuals fulfilled the criteria for a diagnosis of amnestic MCI5 at the time of the CSF examination. Fourteen of 28 patients (male/female ratio, 6:8) progressed over time. They lived independently during a 2-year follow-up and were considered as having progressive MCI.4 Six of 28 subjects (male/female ratio, 3:3) showed clinical progression that warranted a diagnosis of dementia and ultimately met the National Institute for Neurological and Communication Disorders and Stroke/Alzheimer’s Disease and Related Disorders (NINCDS-ADRDA) diagnostic criteria for AD6 and were categorized as having AD-converted MCI.4 In the current study, we enrolled both patients with …