The Expression And Significance Of PEDF And Angâ…¡in Serum And Vitreous In Patients With Proliferative Diabetic Retinopathy

Background and PurposeIn recent years, the incidence of diabetes is increasing year by year with thecontinuous improvement of people’s living standards and the combined effect of anumber of environmental factors, and the incidence of complications of diabetes isalso increasing, diabetic retinopathy (DR) is one of the most severe and commonmicrovascular complications of diabetes, it has become one of the major cause ofblindness in adults, what is more, when DR entered into the late stage, which isproliferative diabetic retinopathy stage, damage of the vision is irreversible.Changes in proliferative diabetic retinopathy are the production of new blood vessels,vitreous hemorrhage or hemorrhage before retinal. These pathological changes aredue to the generation of new blood vessels caused, which is due to the environmentchanges within the eye.At present, the pathogenesis of diabetic retinopathy has notbeen elucidated completely, there are lack of effective approaches for the preventionand treatment in clinical practice. Studies have found that the imbalance ofintraocular angiogenesis stimulating factor and inhibitory factor is the main cause ofdiabetic retinopathy. Pigment epithelium derived factor (PEDF) and angiotensin Ⅱ(Ang Ⅱ) play an important role indiabetic retinopathy, and this opinion has been approved by many researchers. Researchers found that PEDF had the effect ofinhibiting angiogenesis and neuroprotection. AngⅡ may disrupt intraocularblood-retinal barrier and promote the angiogenesis. In this study, the purpose is toinvestigate the expression of PEDF and AngⅡin serum and vitreous in patients withproliferative diabetic retinopathy, to explore the relationship between the two factorsand proliferative diabetic retinopathy.Materials and methods65patients (65eyes) who were underwent vitrectomy in the First AffiliatedHospital of Zhengzhou University Department one of ophthalmology from2013January to2013July. The proliferative diabetic retinopathy (PDR) group were34patients（34eyes）, the control group was31patients (31eyes), including20cases(20eyes) of rhegmatogenous retinal detachment (RRD) patients and11cases (11eyes)of idiopathic macular hole (IMH) patients.The exclusion criteria of control group:major systemic disease, for example diabetes and hypertension and so on, and otherocular lesions.Serum sample: the patients were fasted in the early morning, collected2mLblood from cubital veins,3500r/min,4℃, centrifugation for15min,collected thesupernatant, placed them in sterile EP tube, then placed them in-80℃refrigeratorquickly. Vitreous sample: Undiluted vitreous samples(0.3～1.0mL) were obtainedduring therapeutic vitrectomy, during pars plana Vitrectomy, These samples werecollected in sterile tubes and stored at-80℃refrigerator until use.This experiment use double antibody sandwich enzyme linked immunosorbentassay (ELISA) to measure the expression of PEDF and AngⅡin serum and vitreous.The ELISA kits were purchased from the Beijing Kang Wei Biotechnology Co. ltd.The experimental procedure were carried out strictly according to the the ELISA kitinstruction manuals.Experimental data was analyzed by statistical software SPSS19.0, comparisonbetween the expression of PEDF and AngⅡin serum and vitreous in patients withproliferative diabetic retinopathy was analyzed by the ANOVA for repeated measures. Comparison between the expression of PEDF and AngⅡin serum and vitreous in twogroups was analyzed by two independent samples t test.the relationship between theexpression of PEDF and AngⅡin serum and vitreous in patients with proliferativediabetic retinopathy was analyzed by Pearson correlation, the significant level is0.05.Results1． The serum and vitreous levels of PEDF in PDR group were498.90±85.46μg/L、314.39±86.78μg/L respectively, the serum and vitreous levelsof PEDF in control group were551.19±62.87μg/L、436.99±73.29μg/Lrespectively,the two groups concentration in the serum has a significant difference（P﹤0.05）, thetwo groups concentration in the vitreous has a significant difference （P﹤0.05）.2．The serum and vitreous levels of AngⅡ in PDR group were453.57±81.72ng/L、488.37±84.19ng/L respectively, the serum and vitreous levels of AngⅡ incontrol group were290.17±60.69ng/L、316.46±68.76ng/Lrespectively, the two groupsconcentration in the serum has a significant difference （P﹤0.05）, the two groupsconcentration in the vitreous has a significant difference （P﹤0.05）.3．In PDR group, the Ang Ⅱ levelin vitreous is higher than the Ang Ⅱ levelinserum, concentration has a significant difference （P﹤0.05）.4．In PDR group, the PEDF level in vitreous is lower than the PEDF level inserum, concentration has no significant difference （P﹥0.05）.Conclusion1．The expressions of AngⅡin serum and vitreous increased in the patientswith proliferative diabetic retinopathy, however, the expressions of PEDF in serumand vitreous decreased, PEDF and Ang Ⅱ may participate in the occurrence ofproliferative diabetic retinopathy.2． The higher expressions of AngⅡof serum and vitreous and the lowerexpressions of PEDF of serum and vitreous may promote the occurrence ofproliferative diabetic retinopathy.