Neovascular glaucoma (NVG) is a serious eye disease with a variety of causes.It results from the secretion of growth factors by hypoxic retinal tissue, such as vascular endothelial growth factor (VEGF), but anti-VEGF treatment alone dose not completely inhibit neovascularization.Our previous study found that platelet-derived growth factor-c (PDGF-C) is also an important factor in pathological angiogenesis.However, the role of PDGF-C in the development of NVG remains unknown.
This study was to quantitatively detect the levels of VEGF and PDGF-C in the aqueous humor of patients with NVG and provide a basis for the anti-angiogenesis therapy.
A prospective cohort study was carried out.Sixty-two eyes of 62 patients with advanced NVG and 11 control subjects with age related cataract were included in Xijing Hospital of the Fourth Military Medical University from January 2014 to August 2015.Ten of 62 NVG eyes received retinal photocoagulation and/or cryotherapy, and 16 eyes resulted from central retinal vein occlusion, 20 eyes from diabetic retinopathy, 5 eyes from postopeartion of retinal detachment, 4 eyes from Eales disease and 7 eyes from unknown cause.Iris neovascularization of grade Ⅱ was found in 13 eyes, grade Ⅲ in 29 eyes and grade Ⅳ in 10 eyes.Aqueous humor specimen was collected for 0.1-0.2 ml during the surgery, and the contents of VEGF and PDGF-C in the aqueous humor were detected by ELISA assay.Written informed consent was obtained from each subject prior to any medical procedure.
The VEGF and PDGF-C concentrations in the aqueous humor were (1 138.17±69.31)ng/L and (29.80±1.64)ng/L in the NVG group, respectively, which were significantly higher than (679.54±49.81)ng/L and (18.60±1.85)ng/L in the control subjects (t=20.95, 20.49, both at P<0.01). The VEGF and PDGF-C concentrations in aqueous humor were (1 095.99±52.71)ng/L and (28.55±0.94)ng/L in the retinal photocoagulation group, showing significantly decreases in comparison with (1 146.28±69.57)ng/L and (30.04±1.64)ng/L in the untreatment group (t=-2.160, P=0.034; t=-2.760, P=0.008). The VEGF content in aqueous humor was positively correlated with PDGF-C content in the patients with NVG (r=0.346, P=0.006). However, the aqueous levels of VEGF and PDGF-C were not significantly different among various primary disease groups and different iris neovascularitation gradings (all at P>0.05).
Both VEGF and PDGF-C contents in the aqueous humour are considerably elevated in NVG patients.Retinal photocoagulation and/or cryotherapy can inhibit the release of VEGF and PDGF-C in the aqueous humor.PDGF-C may be a target for the treatment of NVG.