Metabolic characterization of human aqueous humor in relation to high myopia

High myopia is the common eye disorder worldwide, which may contribute to increase the risk of serious disorders including glaucoma and cataract. Although various studies including genomics, transcriptomics, and proteomics have been implicated to identify potential biomarkers (genes or proteins) for predicting high myopia and to reveal the underlying mechanism, the comprehensive metabolomics in relation to high myopia is very limited. In this study, we identified 242 metabolites in aqueous humor (AH) from a set of 40 cataract patients (including 20 with high myopia and 20 for controls), using a non-targeted metabolomic technology, gas chromatography coupled to time-of-flight mass spectrometer (GC/TOF MS). Further statistical analysis showed that 29 metabolites were significantly changed (Variable important for the projection, VIP ≥ 1 and p ≤ 0.05), between those two groups, while only 2 decreased metabolites were included. Moreover, for the first time, metabolite-metabolite correlations for AH were analyzed, which may dissect key regulatory elements or pathways involved in metabolism of amino acids, carbohydrates, and lipids. Accordingly, metabolic network was constructed based on those 29 changed metabolites in patients with high myopia. More than half of the changed metabolites were highly and positively associated, suggesting important roles of pathways involved in the metabolism of these metabolites in relation to high myopia. Altogether, this work not only provided potential biomarkers for the diagnosis and monitoring of high myopia formation, but also provided new insights into the underlying mechanisms.