Abstract
PURPOSE: To characterize proteomic profiles and underlying biological processes in vitreous humor and plasma of patients with proliferative diabetic retinopathy (PDR), diabetic patients without retinopathy (Non_DR), and non-diabetes mellitus patients (Non_DM), and to identify the molecular endotypes within PDR patients. METHODS: Proteomic profiling of paired vitreous humor and plasma samples from 47 PDR patients, 26 Non_DR patients, and 48 Non_DM patients were conducted with Olink platform. The Olink platform includes 13 panels targeting 1161 proteins. Gene set enrichment analysis was applied for enriched pathways, and the K-means clustering method was used to identify different PDR clusters based on vitreous proteomic profiles. RESULTS: Proteomic analysis revealed significant differences in the vitreous humor of PDR patients compared to those in the Non_DR or Non_DM groups, with elevation of carbonic anhydrase (CA) family members as potential contributors to PDR pathophysiology. Plasma samples from PDR group exhibited less profound differences in proteomic profiles compared to the other two groups. Clustering analysis of PDR vitreous samples identified three distinct clusters as molecular endotypes of PDR patients. Of those, Cluster 3 was characterized by enrichment in CCL/CXCL/IL6/IL18 chemokines and pro-inflammatory signaling pathways, which may contribute to more severe PDR phenotypes. CONCLUSIONS: Significant differences in proteomic profiles were observed in PDR patients, especially in vitreous samples, with CA family members identified as potential therapeutic targets for PDR. Endotyping analysis of vitreous samples uncovered unique patient population with enriched CCL/CXCL/IL6/IL18 inflammatory pathways, highlighting the significance of local protein signature changes in PDR disease heterogeneity and its potential applications in patient stratification and therapeutic treatment.