Circulating biomarkers of diabetic retinopathy: a systematic review and meta-analysis

Approximately a third of adults with diabetes have diabetic retinopathy (DR), a potentially blinding eye disease. This study aimed to summarize known biomarkers associated with DR and investigate their potential roles in retinopathy phenotype. All available data from studies analyzing human peripheral blood samples were extracted for meta-analysis. Pathway analysis was subsequently performed on the biomarkers found to be associated with DR. We identified a significant difference in circulating levels of: soluble ICAM-1 (p < 0.0001), asymmetric dimethylarginine (p < 0.001), adrenomedullin (p = 0.04), soluble E-selectin (p = 0.0017), soluble VCAM-1 (p < 0.001) and von Willebrand factor (p = 0.0004), between patients with various stages of DR and patients with diabetes but no retinopathy. Several distinct biomarkers were consistently found to be associated with DR. Many of these biomarkers are known to function in pathways that promote leukocyte adhesion and transmigration into cells, presumably contributing to the characteristic vascular dysfunction observed in DR.