Expression of Long Non-Coding RNA (lncRNA) SNHG5 in Patients with Refractory Diabetic Macular Edema and Its Regulatory Mechanism

Background: The aim of this study was to assess use of lncRNAs as biomarkers in serum and aqueous humor of patients with diabetic macular edema (DME). Material/Methods: Optical coherence tomography and fundus photography were used to analyze the retinal features of the patients. RT-qPCR was used to analyze the differential expression of lncRNA snhg5 in patients who have idiopathic macular hole (MH), DME, or refractory DME. The relationship between SNHG5 and the clinical characteristics of the patients was analyzed. The effect of SNHG5 on the hyperplasia and apoptosis of human retino-microvascular endothelial cells (HRMECs) and its mechanism were analyzed in vitro. Results: Patients with idiopathic MH developed retinal nerve epithelium rupture and retinal fundus thickening, and patients with DME or refractory DME showed significant macular edema with hemorrhaging. The refractory DME patients improved after treatment but still showed significant macular edema and multiple laser scarring. SNHG5 expression was not only low in the atrial fluid and plasma in DME patients, but also lower in the refractory DME group compared to the idiopathic MH patients. SNHG5 expression in the aqueous humor and plasma was negatively correlated with disease duration, body mass index, and levels of fasting blood glucose, glycated hemoglobin, proteinuria, and glycosuria. In the in vitro experiments, SNHG5 expression was significantly downregulated in high glucose-induced HMECs. After SNHG5 overexpression, cell proliferation, angiogenesis, and VEGF-A protein levels were distinctly downregulated. Conclusions: SNHG5 correlates with the development of DME and is a potential target for therapy.