Abstract (eng)
Alzheimer’s disease (AD) is a neurodegenerative disorder and the most commonly diagnosed form of age-related dementia. Pathological hallmarks of AD are neurofibrillary tangles, senile plaques and neuronal cell loss. Currently, AD can only be diagnosed post mortem and therefore there is a great interest to develop biomarkers for an early diagnosis of AD.
In contrast to early onset AD (EOAD), which is caused by gene mutations, late onset AD (LOAD), the most prevalent type of AD, seems to be mediated by aberrant epigenetic modifications. High homocysteine and low folate levels in plasma of AD patients have been associated with hypomethylation of the genome. Aberrant DNA methylation patterns could therefore be suitable biomarkers for the early diagnosis of AD.
In the master thesis, the suitability of the DNA methylation status of monoamine oxidase B (MAOB) as biomarker for the diagnosis of AD was investigated. In previous studies, the MOAB protein has been found to be overexpressed in AD patients.
At the beginning, a pyrosequencing method was developed, allowing to determine the methylation status of 11 CpGs in the MAOB promoter. The pyrosequencing method was then applied to the analysis of DNA extracts from whole blood samples of 40 AD patients and 40 healthy controls. DNA extracts were provided by our cooperation partners from the Institute of Physiology, Medical University of Vienna. In addition, pools of DNA extracts were obtained, prepared by mixing DNA extracts from individual persons.
Statistical analyses of the methylation levels determined showed that the methylation status of the CpGs in DNA from whole blood of AD patients was not significantly different from that found in healthy controls. Significant differences were neither found for DNA extracts from individual persons nor for DNA extract pools.