Abstract
An early diagnosis of Alzheimer’s disease can lead to better and more targeted treatment and/or prevention for patients. Employing a pathological diagnosis by non-targeted metabolomics with ultra high performance liquid chromatography-electrospray tandem mass spectrometry, in our previous study, we found significant changes in polyamine metabolites arising from the ornithine cycle in human brain samples of patients with Alzheimer’s disease. In this study, we develop a targeted metabolomics methodology for the separation and detection of compounds derived from the ornithine cycle in human cerebrospinal fluid samples. For the targeted metabolomics, two derivatization reagents (9-fluorenylmethyl chloroformate and 4-(N,N-dimethylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole) are utilized for sensitive and accurate determination of amine analytes. Validation tests confirm a good linearity of r2>0.99 or more in all calibration curves obtained using internal standards. The developed method is applied for the analysis of preliminary 15 metabolites including polyamine metabolites in cerebrospinal fluid samples classified according to brain autopsy Braak stages regarding to Alzheimer’s disease and compared to a control samples. Utilizing the results obtained for the ornithine cycle, we expect to find a metabolic pathway that would be used as a potential biomarker in the future.
