A Proteomic Study of Different Types of Diabetic Macular Edema.

Purpose: This study investigates distinct protein markers associated with different morphologic features of diabetic macular edema, focusing on diffuse retinal thickening, cystoid macular edema, and cystoid macular degeneration.

Methods: A total of 48 eyes of 33 patients with diabetic macular edema were included in the study and categorized into the aforementioned groups. Preoperative aqueous humor samples were collected from nine diabetic macular edema patients and subjected to tandem mass spectrometry labeling using tandem mass tags quantitative proteomics analysis to compare protein profiles in the aqueous humor among the different morphologic features of diabetic macular edema.

Results: The analysis revealed that the efficacy of anti-vascular endothelial growth factor treatment was significantly better in the diffuse retinal thickening and cystoid macular edema groups compared to the cystoid macular degeneration group (P < 0.05). Differential expression analysis identified 31 upregulated and 43 downregulated proteins in the diffuse retinal thickening group compared to the cystoid macular degeneration group, with upregulated proteins associated with vasoconstriction, apoptotic processes, complement system, and peptidase inhibitors, and downregulated proteins associated with protein kinase and positive regulation of cell cycle regulation. Similarly, the cystoid macular edema group showed 31 upregulated and 32 downregulated proteins compared to the cystoid macular degeneration group, with upregulated proteins associated with the Wnt signaling pathway and extracellular matrix (ECM)-receptor interaction, and downregulated proteins associated with high-density lipoprotein (HDL), cholesterol positive regulation. The screening criteria for differentially expressed proteins were fold change >1.2 or <0.83 and P < 0.05.

Conclusion: Associations were found between cystoid macular degeneration formation and factors like the complement system, apoptotic pathway, and lipid metabolizing factors, providing insights for further understanding diabetic macular edema pathogenesis.