ObjectiveTo investigate the expression and clinical significance of long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and miR-199b in the peripheral blood of patients with proliferative diabetic retinopathy (PDR). MethodsA retrospective clinical study. A total of 473 patients with type 2 diabetes (T2DM) who visited Department of Ophthalmology of West China Airport Hospital of Sichuan University from February 2022 to July 2024 were included in the study. According to the diagnostic criteria for diabetic retinopathy (DR) in the Chinese Clinical Diagnosis and Treatment Guidelines for Diabetic Retinopathy, the T2DM patients were divided into three groups: the non-DR group (NDR group, 130 cases), the non-PDR group (NPDR group, 132 cases), and the PDR group (211 cases). Another 120 patients of the same age and gender who underwent simple cataract surgery during the same period were selected as the cataract group. Blood pressure, and laboratory data including fasting blood glucose (FBG), fasting insulin (FINS), glycated hemoglobin (HbA1c), triglycerides (TG), and high-density lipoprotein cholesterol (HDL-C) were collected in detail for the T2DM group patients. Fasting peripheral venous blood was collected from T2DM group patients; aqueous humor was collected from 45 PDR and NPDR patients with concurrent macular edema before intravitreal injection of anti-vascular endothelial growth factor drugs. The expression levels of lncRNA MALAT1 and miR-199b mRNA in peripheral blood and aqueous humor were detected by quantitative real-time polymerase chain reaction. Receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to analyze the efficacy of lncRNA MALAT1 and miR-199b alone and in combination for predicting PDR occurrence. One-way analysis of variance was used for comparisons among multiple groups. The correlation between the expression levels of the two indicators and each clinical parameter was analyzed using Pearson correlation analysis. ResultsCompared with the NPDR group and the NDR group, the systolic blood pressure, FBG, HbA1c, FINS and TG levels of patients in the PDR group were significantly increased, while HDL-C levels were significantly decreased. The differences were statistically significant (F=42.207, 52.320, 478.335, 107.676, 86.273, 77.653; P＜0.05); the expression of peripheral blood lncRNA MALAT1 was significantly increased, while the expression of miR-199b was significantly decreased, and the differences were statistically significant (F=31.773, 152.784; P＜0.05). Compared with the NPDR group and the cataract group, the expression of lncRNA MALAT1 in the aqueous humor of patients in the PDR group was significantly increased, and the expression of miR-199b was significantly decreased (F=159.700, 114.667; P＜0.05). The correlation analysis results showed that the expression of peripheral blood lncRNA MALAT1 was positively correlated with systolic blood pressure, FBG, HbA1c, TG, and FINS (r=0.318, 0.358, 0.689, 0.474, 0.498), and negatively correlated with miR-199b (r=?0.526) and HDL-C (r=?0.489) (P＜0.05). The expression of miR-199b showed an opposite correlation with the above metabolic indicators (r=?0.419, ?0.425, ?0.712, ?0.516, ?0.541, 0.529; P＜0.05). The expression levels of lncRNA MALAT1 and miR-199b in the peripheral blood and aqueous humor of PDR patients were significantly positively correlated (r=0.732, 0.675; P＜0.05). ROC curve analysis showed that the AUC values of peripheral blood lncRNA MALAT1, miR-199b alone and in combination for predicting PDR were 0.684, 0.796, and 0.861, respectively. ConclusionsPatients with PDR exhibit high expression of lncRNA MALAT1 and low expression of miR-199b in peripheral blood. The expressions of these markers are consistent between peripheral blood and aqueous humor and are associated with glucose and lipid metabolism. Their combination demonstrates high predictive value for the occurrence of PDR.
