Proteomic Biomarkers of Retinal Inflammation in Diabetic Retinopathy

Abstract

Diabetic retinopathy (DR), a sight-threatening neurovasculopathy, is the leading cause of irreversible blindness in the developed world. DR arises as the result of prolonged hyperglycemia and is characterized by leaky retinal vasculature, retinal ischemia, retinal inflammation, angiogenesis, and neovascularization. The number of DR patients is growing with an increase in the elderly population, and therapeutic approaches are limited, therefore, new therapies to prevent retinal injury and enhance repair are a critical unmet need. Besides vascular endothelial growth factor (VEGF)-induced vascular proliferation, several other mechanisms are important in the pathogenesis of diabetic retinopathy, including vascular inflammation. Thus, combining anti-VEGF therapy with other new therapies targeting these pathophysiological pathways of DR may further optimize treatment outcomes. Technological advancements have allowed for high-throughput proteomic studies examining biofluids such as aqueous humor, vitreous humor, tear, and serum. Many DR biomarkers have been identified, especially proteins involved in retinal inflammatory processes. This review attempts to summarize the proteomic biomarkers of DR-associated retinal inflammation identified over the last several years.

Keywords: Biomarkers; Diabetic retinopathy; Proteomics; Retinal inflammation.

Figure 1

Summary of differentially expressed proteins identified in biofluids of DR patients. (A) The number of potential biomarkers of retinal inflammation in each biofluid, as identified by the studies discussed in this review. (B) The bar graphs represent fold change in expression of 19 biomarkers identified in at least two biofluids. * AGP and APOA4 proteins were detected in the AH of DR patients, but fold change was not available.