Correlation of Alpha Power with Amino Acid Concentration in Blood Plasma of Pre-symptomatic Alzheimer Population

HARBESON 34

Evidence suggests that pre-symptomatic Alzheimer’s disease (AD) patients and cognitively healthy study participants with pathological amyloid and tau (CH-PAT) have abnormal brain activity compared to cognitively healthy study participants with normal amyloid and tau (CH-NAT). The concentration of certain amino acid is also found to be abnormal in blood plasma of Alzheimer’s patients. The aim of this study is to investigate whether these plasma amino acids and neurotransmitters abnormalities are correlated with brain alpha waves measured using electroencephalography (EEG). Blood samples were collected in order to measure the concentration of amino acids and neurotransmitters. The concentrations of 64 different amino acids were measured with the use of the EzFaast kit used for derivatization followed by liquid chromatography-tandem mass spectrometry (LC/(MS)²). Levels of amino acid A were higher in CH-NAT while levels of the post-translational modified form (PTM-A) were higher in AD. Our results show that levels of amino acid A quantified in plasma have a positive correlation in CH-NAT while its PTM-A has a negative correlation in CH-NAT. However, there was no correlation between amino acid A and PTM-A in CH-PAT. Then these results suggest that posttranslationally modified amino acids can be a biomarker of AD and may contribute to presymptomatic pathology.