Abstract
PURPOSE: To search for differential metabolites in patients with proliferative diabetic retinopathy (PDR), patients with nonproliferative diabetic retinopathy (NPDR), and control subjects, and to study their potential biomarkers in depth. PATIENTS AND METHODS: An untargeted metabolomic approach based on ultra-performance liquid chromatography-tandem mass spectrometry was used to study aqueous humor from 63 patients with PDR, 37 patients with NPDR, and 30 non-diabetic controls. Differential metabolites in different periods of diabetic retinopathy (DR) were identified using orthogonal projections to latent structure discriminant analysis and fold-change. Further logistic regression and receiver operating characteristic curve analysis were performed to select and validate potential biomarkers. RESULTS: Compared to the control group, the PDR group had 80 differential metabolites, among which 3-methylhistamine, N-acetyl-L-histidine, and cytosine were identified as potential biomarkers, whereas the NPDR group had 94 differential metabolites, among which and N-acetyl-L-histidine and hypoxanthine were identified as potential biomarkers. Relative to the PDR and NPDR groups, 5-hydroxyindole-3-acetic acid and L-3-hydroxykynurenine may be potential biomarkers suggesting DR developmental stage or progression. CONCLUSION: The metabolite profiles identified in this study provide insights into the mechanisms of DR onset and progression in future studies and may eventually inform the development of metabolic biomarkers for prognosis and new therapeutic strategies for DR management.