Objective      To determine the serum metabolic changes in the patients with Alzheimer’s disease (AD) and Parkinson’s disease (PD).       Methods      Serum samples of normal human

AD and PD patients diagnosed clinically were collected

and then NMR

1

H spectra were performed and analyzed by principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA).       Results      PCA and OPLS-DA analyses showed that there were great differences i

n serum metabonomics among normal human

AD and PD patients. Compared with normal people

AD patients had higher levels of isoleucine and lactate (P0.05)

and lower levels of lipid

glutamine

creatine and glucose (P0.05)

while the levels of lactate and glutamine were increased (P0.05

P0.01)

and that of glucose was decreased in PD patients (P0.01). The serum levels of lipid

lactate and glutamine were significantly higher (P0.05

P0.01)

while those of isoleucine

alanine and glucose were lower in the PD patients than the AD patients (P0.05

P0.01).       Conclusion      Distinct differences exist in the serum metabolic profiles between the AD and PD patients

and these distinct metabolites may serve as potential biomarkers to distinguish AD from PD in clinical practise.