Expression of erythropoietin in neovascular glaucoma and its role in the angiogenesis in vitro

Abstract

Objective: To explore the expression of erythropoietin (EPO) in neovascular glaucoma (NVG) and its role in the angiogenesis in vitro. Methods: The levels of EPO in aqueous humor and vitreous body of NVG patients (10 cases) and non-NVG patients (10 cases) were detected by enzyme-linked immunosorbent assay (ELISA). Human umbilical vein endothelial cells (HUVECs) were used as the research object, and were divided into EPO 0.1, 1, 10 U/ml group according to EPO concentration, on the basis of treatment of HUVECs cells with 10 ng/ml vascular endothelial growth factor (VEGF). Effect of different concentrations of recombinant human EPO and VEGF on the proliferation, angiogenesis and the formation of capillary like structures of HUVECs in vitro was explored, meanwhile, protein and mRNA expression of hypoxia inducible factor-1α (HIF-1α) was detected by Western blot and RT-PCR. Results: In the study, no patients discontinued the trial. EPO level of aqueous humor in non-NVG patients was (29.4±0.6) ng/L, while EPO level in aqueous humor of NVG patients reached (307.5±7.6) ng/L, and the difference was statistically significant (t=2.186, P=0.039); vitreous EPO levels in non-NVG patients was (16.7±1.2) ng/L, while vitreous EPO levels in NVG patients reached (267.5±11.4) ng/L, with a statistically significant difference (t=2.517, P=0.019). Compared with control group, 0.1, 1, 10 U/ml EPO and 10 ng/ml VEGF promoted the proliferation of HUVECs, and formation of vascular lumen-like and capillary-like structure in vitro, and up-regulated the protein and mRNA expression of HIF-1α (all P<0.05). Conclusion: EPO was highly expressed in the NVG patients, and exogenous EPO could significantly promote the proliferation of HUVEC and formation of vascular lumen-like and capillary-like structure, which may be related to up-regulation of HIF-1 expression.