Elevated plasma and vitreous levels of leucine‐rich‐α2‐glycoprotein are associated with diabetic retinopathy progression

PURPOSE: To investigate the association of plasma and vitreous leucine-rich-α2-glycoprotein (LRG1) with diabetic retinopathy (DR) progression. METHODS: A total of 86 outpatients and 33 inpatients were recruited. Outpatients with type 2 diabetes mellitus (T2DM) were classified as T2DM without DR (n = 22), nonproliferative DR (NPDR) (n = 20) and proliferative DR (PDR) (n = 22) based on international clinical DR severity scales. A total of 86 plasma and 33 vitreous samples were collected and subjected to enzyme-linked immunosorbent assay. The diagnostic value of plasma LRG1 was tested using receiver operating characteristic (ROC) curves. RESULTS: Plasma LRG1 in PDR patients (9025 ± 1870 pg/ml) was significantly increased as compared with controls (5975 ± 2022 pg/ml), T2DM without DR (6550 ± 2359 pg/ml) and NPDR patients (6550 ± 2359 pg/ml) (p < 0.0001). Vitreous LRG1 in PDR patients was elevated by approximately 4.3-fold than that in controls (562.1 ± 273.5 ng/ml versus 130.0 ± 102.8 ng/ml, p = 0.000). The area under the ROC curve value for plasma LRG1 was 0.786 (p < 0.0001). The maximal Youden index was 0.4372 and the optimal cut-off value of LRG1 was 7357.043 pg/ml with 81.82% sensitivity and 61.90% specificity. CONCLUSION: Plasma and vitreous LRG1 levels were elevated in patients with PDR. Leucine-rich-α2-glycoprotein (LRG1) might be a potential risk-warning marker for PDR.