Blood expression and methylation status in Alzheimer's disease.

AIM

This study aimed to investigate the expression levels and methylation status of () in the blood of Alzheimer's disease (AD) patients and age- and sex-matched healthy controls.

METHODS

Fifty AD outpatients and 50 healthy contorls were enrolled. Blood samples were collected for processing of complementary DNA and genomic DNA. messenger ribonucleic acid (mRNA) expression was analyzed by real-time quantitative polymerase chain reaction. The methylation rates of four cytosine-phosphate-guanine (CpG) sites in the upstream region of exon1 were evaluated by the pyrosequencing method.

RESULTS

No significant differences in mRNA expression levels were found between AD and control subjects (AD 0.97 ± 0.49 vs. control 1.0 ± 0.64,  = 0.62). mRNA expression levels were not correlated with any other clinical characteristics or results of psychological tests. mRNA expression levels were significantly higher in AD subjects treated with acetylcholinesterase inhibitors (AchEIs) ( = 25) than in subjects not treated with AChEIs ( = 25) (unmedicated 0.83 ± 0.33 vs. medicated 1.12 ± 0.59,  = 0.049). The AD subjects did not differ from the control subjects in methylation rates at selected CpG sites. methylation status were not correlated with clinical characteristics, the results of psychological tests, or mRNA expression.

CONCLUSION

mRNA expression levels and methylation status in blood do not appear useful as biomarkers for AD or the examined CpG sites were not genetically significant for gene expression or AD pathology. However, AChEIs may alter mRNA expression. Further studies are needed to explore blood biomarkers that can discriminate AD patients from controls.