engleski

Platelet serotonin concentration and monoamine oxidase activity in early-, mid- and late-stage of the Alzheimer's Disease

Post mortem brain studies found the loss of serotonergic neurons and the decrease in the brain serotonin (5-HT) concentration in patients with Alzheimer’ s disease (AD). Blood platelets have been proposed as an easy obtainable peripheral model for some processes in the central serotonergic neurons. The aim of the study was to determine platelet 5-HT concentration and platelet monoamine oxidase type B (MAO-B) activity in early-, mid- and late- stage of AD. The study included 93 (25 men, 68 women) patients with AD (NINCDS-ADRDA and DSM-IV-TR criteria). The patients were subdivided according to the mini-mental state examination (MMSE) scores into groups: a) 39 patients (mean ± ; SD age 66.3 ± ; 11.2 years) in early-stage of AD with MMSE > 18 (mean ± ; SD, 20.6 ± ; 1.5), b) 25 patients (74.9 ± ; 9.7 years) in mid-stage of AD with MMSE scores from 10-17 (14.3 ± ; 2.1), and c) 29 patients (82.0 ± ; 7.9 years) in late-stage of AD with MMSE scores < 9 (2.0 ± ; 1.9). Platelet 5- HT concentration and platelet MAO-B activity were determined spectrofluorimetrically. Results were evaluated using Kruskal- Wallis ANOVA on rangs and Mann-Whitney’ s test and Spearman’ s coefficient of correlation. A sex difference in platelet 5-HT concentration, but not in MAO-B activity, was found in patients with AD. Female patients had lower 5-HT concentration than male patients. A significant decrease in platelet 5-HT concentration was found in female AD patients in the late-stage of disease compared to platelet 5-HT values in female patients with early- and mid-stage of AD. Platelet MAO-B activity was significantly reduced in female patients in late-stage of AD compared to MAO-B activity in early stages of AD. Due to the small number of male patients, their platelet 5-HT concentration and MAO-B activity did not differ according to the different stages of AD. There were significant correlations between MMSE scores and platelet 5-HT levels or MAO-B activity. The results showed reduced platelet 5-HT and MAO-B values during the course of AD, which correlate with the severity of dementia. Platelet 5-HT concentration and MAO-B activity should be further evaluated as markers for severity and/or clinical progress of AD.

Alzheimer’ s disease; mini-mental state examination; platelet 5-HT concentration; platelet monoamine oxidase activity; early-; mid- and late- stage of AD

Indexed / Abstracted in: Neuroscience Citation Index ; EMBASE / Excerpta Medica