The Levels Of Platelet-derived Growth Factor-C And Vascular Endothelial Growth Factor In Aqueous Humor Of Patients With Neovascular Glaucoma

Neovascular glaucoma(NVG) is one of serious blindness diseases, which is caused by the intraocular tissue ischemia and hypoxia. The iris and anterior chamber angle neovascularization may eventually lead to aqueous humor outflow obstruction and sustained elevation of intraocular pressure(IOP). The common primary diseases of NVG are diabetic retinopathy, central retinal vein occlusion, and etc. The treatment of NVG is intractable, so it is listed as a major branch of the refractory glaucoma.The pathogenesis of neovascular glaucoma is unclear, but it has been discovered that various angiogenic factors take part in the progress of NVG. At present, many studies show that vascular endothelial growth factor(VEGF) plays a key role in intraocular pathologic neovascularization, anti-VEGF agent has been widely used for the treatment of ocular neovascularization diseases. In recent years, a large number of clinical reports show that anti-VEGF agent is effective in the treatment of neovascular glaucoma. Anti-VEGF therapy can inhibit iris and anterior chamber angle neovascularization, but the efficacy ofanti-VEGF therapy alone is limited. If combined with other antiangiogenic agents may show significant benefit in NVG treatment. It is reported that platelet-derived growth factor-C(PDGF-C) also involves in intraocular pathological neovascularization, but the role of PDGF-C in NVG is unknown. In this study, we analyzed the role of the PDGF-C and VEGF in the progress of NVG by detecting the levels of VEGF and PDGF-C in the aqueous humor of patients, and to find a new antiangiogenic agent to treat neovascular glaucoma.Objective The subject of this study is to quantify and analyze PDGF-C and VEGF in the aqueous humor of patients with neovascular glaucoma, to study the relationship between NVG and PDGF-C/VEGF.Methods Prospectively clinical study. This study involved 34 eyes of 34 patients with advanced NVG requiring antiglaucomatous surgery, 13 eyes with primary open-angle glaucoma(POAG) and 11 eyes with age related cataract. Enzyme-linked immunosorbent assay(ELISA) was used to quantify analyze the concentrations of PDGF-C and VEGF in aqueous humor from patients with NVG, POAG and age related cataract. Of the 34 eyes,19 had central retinal vein occlusion(CRVO), 15 had diabetic retinopathy(DR). Among them, the number of NVG eyes with iris neovascularization gradesⅡ, Ш and IV were 10,15 and 9, respectively, and 13 eyes were ever treated with retinal photocoagulation.Aqueous humor samples were obtained through anterior chamber paracentesis during surgery.Results1 The PDGF-C and VEGF concentrations in aqueous humor from NVG patients were(29.49±1.47) ng/L and(1128.11±61.70) ng/L, respectively; both were significantly higher than concentrations in POAG and age related cataract eyes(both P<0.01). The PDGF-C and VEGF concentrations in aqueous humor from POAG patients were(23.82±1.10) ng/L and(888.68±60.56) ng/L, respectively; both were significantly higher than the age relatedcataract eyes(18.60±1.85) ng/L,(679.54±49.81) ng/L, respectively(both P<0.01).2 The aqueous humor levels of PDGF-C and VEGF were not significantly different in different NVI groups and underlying diseases(all P>0.05).3 There was no significant correlation between the aqueous level of PDGF-C and VEGF in patients with NVG(r=0.317, P=0.068), and the PDGF-C and VEGF levels were not significantly correlated with the preoperative IOP in the NVG group(all P>0.05).4 The PDGF-C and VEGF concentrations in aqueous humor of NVG patients who were ever treated with retinal photocoagulation were(28.71±1.18) ng/L and(1091.98±38.35)ng/L, respectively; both were significantly lower than untreated NVG(29.98±1.44) ng/L,(1150.47±63.44) ng/L, respctively(both P<0.05).Conclusion The results above reveal that VEGF plays an important role in the process of NVG pathogenesis, in addition, PDGF-C also participated in intraocular pathological neovascularization. A combination therapy approach, using both PDGF-C and VEGF inhibitors, may be a more effective intervention for angiogenesis of NVG. And retinal photocoagulation may be reduce the levels of PDGF-C and VEGF in aqueous humor from patients with NVG by relieving retinal ischemia and hypoxia.