Measurement Of Vascular Endothelial Growth Factor And Erythropoietin In The Vitreous Of Proliferative Diabetic Retinopathy

Diabetic retinopathy(DR)is a major ocular complication of diabeticmellitus and it is one of the leading causes of blindness in the world. Itis characterized by increased vascular permeability, ischemia, andneovascularization. The most important causes of blindness are vitreoushemorrhage induced by neovascularization, fibrovascularmembrane, tractional retinal detetchment and othercomplications. Although Vascular endothelial growth factor(VEGF) is aprimary mediator of retinal angiogenesis, VEGF inhibit alone isinsufficient to prevent from retinal neovascularization. Hence, it ispostulated that there are other potent ischemia-induced angiogenicfactors. Erythropoietin possesses angiogenic activity, antiapoptoticactivity, but its potential role in ocular is not established.Objectives:To determine the levels of VEGF and EPO in the vitreous of proliferativediabetic retinopathy, analyze their changes, discuss the role of VEGF andEPO in the pathogenesis of PDR and provide the theoretical evidence forthe prevention and treatment of PDR and research antiangiogenic medicine.Meathods:Double antibody sandwich enzyme-linked immunosorbent assay (ELISA)wasused to measure the level of VEGF concentration and radioimmunoassay(RIA) was used to measure the level of EPO concentration in vitreous ofproliferative diabetic retinopathy(PDR) and the control group.Results:1. The mean VEGF concentration is 956.25pg/ml (393.75-2237.50pg/ml)in vitreous of PDR patients and 77.89pg/ml(45.26-134. 97pg/ml) in normalgroup. The VEGF concentration in vitreous of PDR patients issignificantly higher than the level in normal group (P＜0.05).2. The mean EPO concentration is 391.95mIU/ml (90.10-1111.35mIU/ml) invitreous of PDR patients and12.43mIm/ml(0.13-18.51mIU/ml) in normalgroup. The EPO concentration in vitreous of PDR patients is significantlyhigher than the level in normal group(P＜0.05).3. For the patients with PDR, the VEGF concentration is711.30pg/ml(393.75-1518.75pg/ml)in vitreous atⅤstage and1581.25pg/ml(956.25-2237.50pg/ml) atⅥstage. The VEGF concentrationin vitreous atⅥstage is significantly higher than the level atⅤstage(P＜0.05).4. For the patients with PDR, the EPO concentration is246.30mIU/ml(90.10-821.80mIU/ml) in vitreous at Vstage and793.25mIU/ml(128.55-1111.35mIU/ml) atⅥstage. The EPO concentrationin vitreous atⅥstage is significantly higher than the level atⅤstage(P＜0.05).5. For the patients with PDR, the VEGF concentration is738.43pg/ml(393.75-1112.50pg/ml) in vitreous with A group(fibrovascularmembrane is less than two quadrants, including two quadrants ) and1300. OOpg/ml(456.25-2237.50pg/ml) with B group(fibrovascular membraneis more than two quadrants) The VEGF concentration in vitreous with B group is significantly higher than the level with A group (P＜0.05).6. For the patients with PDR, the EPO concentration is250.65mIU/ml(90.60-896.50mIU/ml)in vitreous with A group(fibrovascularmembrane is less than two quadrants, including two quadrants ) and467.85mIU/ml(90.10-1111.35mIU/ml) with B group(fibrovascular membraneis more than two quadrants). The EPO concentration in vitreous with Bgroup is significantly higher than the level with A group (P＜0.05).7. For the patients with PDR, the VEGF concentration is690.63pg/ml(393.75-1112.50pg/ml) in vitreous with PRP(panretinalphotocoagulation) patients, 1425.00pg/ml(456.25-2237.50pg/ml)withoutPRP and70.49pg/ml(48.79-134. 19pg/ml) in control group, the VEGFconcentration is significantly lower than the level with without PRP (P＜0.05)and higher than control group(P＜0.05).8. For the patients with PDR, the EPO concentration is151.95mIU/ml(90.10-468.40mIU/ml) in vitreous with PRP(panretinalphotocoagulation) patients, 541.88mIU/ml(118.25-1111.35 mIU/ml)withoutPRP and 12.43mIU/ml(0.13-18.51mIU/ml) in control group, the EPOconcentration is significantly lower than the level with without PRP (P＜0.05)and higher than control group(P＜0.05).9. For the patients with PDR, the VEGF concentration is 893.75pg/ml invitreous with nephropathy and 1096.88pg/ml without nephropathy, there isno significantly statistic difference(P＞0.05).10. For the patients with PDR, the EPO concentration is 289.83 mIU/ml,in vitreous with nephropathy and 468.40 mIU/ml without nephropathy, thereis no significantly statistic difference(P＞0.05).11. For the patients with PDR, the VEGF concentration is 1831.25pg/ml in vitreous with hypertention and 1096.88pg/ml withouthypertention, there is no significantly statistic difference(P＞0.05).12. For the patients with PDR, the EPO concentration is 448.33mIU/ml invitreous with hypertention and 251.20 mIU/ml without hypertention, thereis no significantly statistic difference(P＞0.05).13. For the patients with PDR, there is correlation between the VEGFconcentration and the EPO concentration(r=0.587, p=0.001).14. For the patients with PDR, there is no correlation between the sex,the age, duration, fasting blood glucose(FBG)and the level of VEGF andEPO concentration in vitreous.Conclusions:1. VEGF level in the vitreous of PDR patients was elevated, which wascorrelated with the angiogenesis in diabetic retinopathy.2. EPO level in the vitreous of PDR patients was elevated, which wascorrelated with the angiogenesis in diabetic retinopathy.3. For the patients with PDR, there was a correlation between VEGFconcentration and EPO concentration. EPO may have angiogenic potencyequivalent to that of VEGF in patients with PDR.4. After PRP treatment, VEGF level and EPO level in the vitreous of PDRpatients was decreased, but can not reach the normal level yet. PRPtreatment may inhibit angiogenic activity but still can not make themreach the normal level.5. For the patients with PDR, there is no correlation betweenproteinuria, blood pressure, blood glucose, duration and the level ofVEGF and EPO in vitreous.6. For the patients with PDR, there is no correlation between age, sex and the level of VEGF and EPO in vitreous.