Metabolomics profiling reveals altered lipid metabolism and identifies a panel of lipid metabolites as biomarkers for Parkinson's disease related anxiety disorder.

Objectives: Anxiety disorder is a common non-motor symptom in patient with Parkinson's disease (PD). We aimed to explore its pathogenesis and identify plasma biomarkers using untargeted metabolomics analysis.

Methods: Consecutive PD patients and healthy controls were recruited. Clinical data were assessed and patients with Parkinson's disease related anxiety disorder (PDA) were recognized. Fast plasma samples were obtained and untargeted liquid chromatography-mass spectrometry-based metabolomics analysis was performed. Based on the differentially expressed metabolites from the above metabolomics analysis, correlation analyses and receiver operating characteristic curves (ROC) were further employed.

Results: According to the clinical data, PDA patients had lower plasma levels of total cholesterol, triglyceride, low-density lipoprotein cholesterol, and apolipoprotein B. There were thirty-nine differentially expressed metabolites in PDA patients when compared with the other two groups from the metabolomics analysis, respectively. Fourteen lipid metabolites were simultaneously altered between these two groups, and all of them were significantly decreased. They can be further subcategorized into fatty acyls, glycerolipids, sterol lipids, sphingolipids, and prenol lipids. The plasma levels of thirteen metabolites were negatively correlated with HAMA scores except 10-oxo-nonadecanoic acid. Based on the ROC curves, the fourteen lipid metabolites can be diagnostic biomarkers for PDA patients separately and the areas under the curve of the fourteen lipid metabolites ranged from 0.681 to 0.798.

Conclusions: Significantly lower plasma lipoproteins can be found in PDA patients. A panel of fourteen lipid metabolites were also significantly decreased and can be clinical biomarkers for the diagnosis of PDA patients.