title: Can Salivary Acetylcholinesterase be a Diagnostic Biomarker for Alzheimer?
abstract: BACKGROUND
  The loss of brain cholinergic activity is a key phenomenon in the biochemistry of Alzheimer's Disease (AD). Due to the specific biosynthesis of Acetylcholinesterase (AChE) of cholinergic neurons, the enzyme has been proposed as a potential biochemical marker of cholinergic activity. AChE is expressed not only in the Central Nervous System (CNS), Peripheral Nervous System (PNS) and muscles, but also on the surface of blood cells and saliva.
  
  
  OBJECTIVE
  This study aimed to measure salivary AChE activity in AD and to determine the feasibility of creating a simple laboratory test for diagnosing such patients.
  
  
  METHODS
  In this cross-sectional study, the recorded data were obtained from 15 Alzheimer's patients on memantine therapy and 15 healthy subjects. Unstimulated whole saliva samples were collected from the participants and salivary levels of AChE activity were determined by using the Ellman colorimetric method. The Mann Whitney U test was used to compare the average (median) of AChE activity between AD and controls. In order to adjust for possible confounding factors, partial correlation coefficient and multivariate linear regressions were used.
  
  
  RESULTS
  Although the average of AChE activity in the saliva of people with AD was lower compared to the control group, we found no statistically significant differences using Mann Whitney U test (138 in control group vs. 175 in Alzheimer's patients, p value=0.25). Additionally, no significant differences were observed in the activity of this enzyme in both sexes or with increased age or duration of the disease. After adjusting for age and gender, there was no association between AChE activity and AD (regression coefficient β=0.08; p value= 0.67).
  
  
  CONCLUSIONS
  Saliva AChE activity was not significantly associated with AD. This study might help in introduce a new diagnostic aid for AD or monitor patients with AD.
authors.affiliation: Associate Professor, Department of Oral Medicine, Dental Faculty, Shahid Beheshti University of Medical Sciences , Tehran, Iran .
authors.forename: Sedigheh
authors.initials: S
authors.lastname: Bakhtiari
authors.affiliation: Assistant Professor, Department of Neurology, Imam Hossein Hospital, Shahid Beheshti University of Medical Sciences , Tehran, Iran .
authors.forename: Nahid Beladi
authors.initials: NB
authors.lastname: Moghadam
authors.affiliation: General Practioner, Dental Faculty, Shahid Beheshti University of Medical Science , Tehran, Iran .
authors.forename: Marjan
authors.initials: M
authors.lastname: Ehsani
authors.affiliation: Associate Professor, Department of Oral Medicine, Dental Faculty, Shahid Beheshti University of Medical Sciences , Tehran, Iran .
authors.forename: Hamed
authors.initials: H
authors.lastname: Mortazavi
authors.affiliation: Associate Professor, Department of Clinical Epidemiology, School of Health, Shahid Beheshti University of Medical Sciences , Tehran, Iran .
authors.forename: Siamak
authors.initials: S
authors.lastname: Sabour
authors.affiliation: Associate Professor, Department of Oral Medicine, Dental Faculty, Shahid Beheshti University of Medical Sciences , Tehran, Iran .
authors.forename: Mahin
authors.initials: M
authors.lastname: Bakhshi
keywords: Cholinesterase; Dementia; Exploring; Fluid biomarker