Platelet monoamine oxidase B activity in dementia. A 4-year follow-up
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Abstract:
Platelet monoamine oxidase B (MAO-B) activity has been found to increase significantly in demented patients. For the first time, a 4-year follow-up of platelet MAO-B activity and Mini-Mental State (MMS) was performed in patients with probable dementia of the Alzheimer type (DAT) and age-matched controls. MAO-B activity of DAT patients increased significantly 2 years after the beginning of the study as compared with controls and remained significantly higher for the entire period of the examinations (p < 0.0001). The decrease of the MMS scores did not correlate with the time course of the increase of platelet MAO-B activity (Spearman rank correlation test). The decline of the MMS scores of DAT patients preceded the elevation of MAO-B activity. Since degenerative processes in brain areas which are responsible for cognitive function and are reflected by the MMS scores rather affect cerebral cholinergic than monoaminergic neurotransmitter systems, degeneration of the latter at late stages of DAT might be reflected by increased platelet MAO-B activity.
Insights
Platelet monoamine oxidase B (MAO-B) activity rises in Alzheimer's patients over time. This increase in MAO-B does not correlate with cognitive decline, suggesting it may reflect later-stage neurodegeneration.
Area of Science:
- Neuroscience
- Biochemistry
- Gerontology
Background:
- Elevated platelet monoamine oxidase B (MAO-B) activity is observed in patients with dementia.
- Alzheimer's disease (DAT) is a progressive neurodegenerative disorder characterized by cognitive decline.
Purpose of the Study:
- To investigate the longitudinal relationship between platelet MAO-B activity and cognitive function (Mini-Mental State - MMS) in patients with probable dementia of the Alzheimer type (DAT).
- To establish a 4-year follow-up of MAO-B activity and MMS scores in DAT patients and age-matched controls.
Main Methods:
- A 4-year longitudinal study involving patients with probable DAT and age-matched healthy controls.
- Measurement of platelet monoamine oxidase B (MAO-B) activity.
- Assessment of cognitive function using the Mini-Mental State (MMS) examination.
- Statistical analysis including Spearman rank correlation to assess relationships between variables.
Main Results:
- Platelet MAO-B activity significantly increased in DAT patients compared to controls starting from year 2 and remained elevated throughout the 4-year study period (p < 0.0001).
- The decline in MMS scores did not correlate with the time course of increasing platelet MAO-B activity.
- Cognitive decline (decrease in MMS scores) was observed to precede the elevation of platelet MAO-B activity in DAT patients.
Conclusions:
- Increased platelet MAO-B activity is a significant longitudinal finding in probable Alzheimer's disease.
- The observed elevation in MAO-B activity does not directly correlate with the rate of cognitive decline, suggesting it may not be an early marker of cholinergic system degeneration.
- Elevated MAO-B activity might reflect degenerative processes in monoaminergic systems occurring at later stages of Alzheimer's disease.
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