Purpose: To identify the differential profiles of lipids in aqueous humor (AH) between control and diabetic cataract patients.
Methods: The lipidomic profiles of 19 samples from patients with diabetic cataract (diabetic group) and 32 controls (control group) were analyzed using liquid chromatography tandem mass spectrometry (LC-MS/MS). Differentially expressed lipids between the two groups were determined through partial least-squares-discriminant analysis and principal component analysis. Receiver operating characteristic curve was calculated to evaluate the diagnostic value of differentially expressed lipids in distinguishing diabetic cataract patients from the control subjects. The correlations of the target lipids with the serum lipids were determined by Pearson correlation.
Results: The results of LC-MS/MS analysis revealed a remarkable variation in lipid class composition. As compared with the control group, the percentage of triglycerides (TGs) was higher and that of Ceramide-1-phosphates was significantly lower in the AH of the diabetic group. A multivariate analysis of the lipid species showed that the expression levels of 16 of 639 lipids significantly changed in the diabetic group as compared to the control group. Among them, TG (42:6) (area under curve [AUC] = 0.985, P < 0.0001) and diacylglycerol (DG) (24:2) (AUC = 0.944, P < 0.0001) exhibited high prediction capability for diabetic cataract. The results of Pearson correlation revealed that the concentrations of TG (42:6) in AH were positively correlated with serum TG levels in diabetic patients.
Conclusions: The lipid composition of AH of diabetic cataract patients showed a significant difference from that of the healthy subjects. Lipid changes, especially the high AH levels of TG (42:6) and DG (24:2), might contribute to cataractogenesis and possibly be involved in the development of diabetic cataract.
Translational relevance: Changes in the lipid profile of AH may partly account for the pathogenesis of diabetic cataracts and lead to a novel therapeutic strategy for diabetic cataract.