A Possible New Diagnostic Biomarker in Early Diagnosis of Alzheimer's Disease

Early diagnosis in patients with Alzheimer's disease (AD) is of great importance since only a sufficient treatment in early stages of this disease helps to keep patients in an autonomous state for as long as possible. Until now, there is no single diagnostic biomarker for AD derived from material routinely obtained. In this study, proton nuclear magnetic resonance (1H-NMR) spectra of the cerebrospinal fluid (CSF) of AD patients were compared with 1H-NMR spectra of the CSF of healthy control subjects using a metabonomic approach. The 1H-NMR spectra of CSF of AD patients showed specific multipletts at 2.15 ppm and 2.45 ppm, which could not be detected in the majority (59.3% and 70.4%, respectively) of healthy control subjects (positive likelihood ratio (+LR) 2.33, 95% CI [1.46, 3.72], p<0.01; +LR 3.22, 95% CI [1.78, 5.78], p<0.01). Moreover, CSF 1H-NMR spectra of AD patients showed specific resonances at 7.03 ppm (+LR 3.38, 95% CI [1.60, 7.14], p<0.05), 7.19 ppm (+LR 2.89, 95% CI [1.46, 5.74], p<0.05), 7.43 ppm (+LR 3.15, 95% CI [1.47, 6.75], p<0.05), and at 7.91 ppm (+LR 3.38, 95% CI [1.60, 7.14], p<0.01). CSF 1H-NMR spectroscopy is obviously a capable method for detection and quantification of substances in the CSF of AD patients even without the knowledge of molecular structures. These substances can be used as a biomarker in the early diagnosis of AD. We assume that this biomarker will simplify the diagnosis of AD, especially in early stages of the disease.