血浆同型半胱氨酸及糖化血红蛋白在糖尿病视网膜病变诊断中的应用

目的探讨血浆同型半胱氨酸（Hcy）及糖化血红蛋白（HbA1c）在糖尿病视网膜病变（DR）诊断中的应用价值。方法对45例DR患者（DR组）、55例无视网膜病变的2型糖尿病患者（NDR组）及40例健康体检者（对照组）采用双抗体夹心ELISA法和免疫比浊法检测其血浆Hey和HbA1c水平。结果DR组与NDR组患者血浆Hcy和HbA1c水平均高于对照组,（P〈0．05）,DR组血浆Hey和HbA1c水平高于对照组（P〈0．05）。结论检测血浆Hcy和HbA1c水平可早期诊断DR。     

FPG、HbA1c水平变化与老年2型糖尿病视网膜病变患者视力严重程度的关系

目的 探究空腹血糖（Fasting Blood Glucose, FPG）、糖化血红蛋白（Glycosylated Hemoglobin A1c, HbA1c）水平变化与老年2型糖尿病视网膜病变患者视力严重程度的关系。方法 选取2020年6月—2022年6月泉州市泉港区医院收治的92例2型糖尿病患者为研究对象,根据有无视网膜病变分为非视网膜病变组48例、视网膜病变组44例;根据视力损伤严重程度将视网膜病变患者分为轻度组15例、中度组14例、重度组15例。所有患者入院次日检测空腹血糖和视力情况,分析不同组间FPG、HbA1c水平;Pearson相关性分析FPG、HbA1c水平变化与患者视力严重程度关系。结果 视网膜病变组FPG和HbA1c水平均明显高于非视网膜病变组,差异有统计学意义（P均<0.05）。中重度组FPG和HbA1c水平均明显高于轻度组,且重度组高于中度组,差异有统计学意义（P均<0.05）。FPG、HbA1c与糖尿病视网膜病变患者视力损伤程度呈正相关（r=0.436、0.531,P均<0.001）。结论 老年2型糖尿病视网膜病变患者FPG与HbA1c水平与...     

2型糖尿病患者中阻塞性睡眠呼吸暂停低通气综合征与糖尿病微血管病变相关性的初步分析

目的 初步分析阻塞性睡眠呼吸暂停低通气综合征（OSAHS）与糖尿病微血管病变的相关性.方法 选取2012年至2013年河南省人民医院内分泌科共239例2型糖尿病（T2DM）患者为研究对象,采用密歇根神经病变筛查表、体感诱发电位与神经传导速度诊断糖尿病周围神经病变（DPN）,采用尿白蛋白/肌酐比值诊断糖尿病肾脏病变（DN）,采用眼底检查诊断糖尿病视网膜病变（DR）,并依次分为DPN组（97例）和非DPN组（142例）、DN组（74例）和非DN组（165例）、DR组（87例）和非DR组（152例）,检测患者糖化血红蛋白（HbA1c）及相关生化指标,采用酶联免疫吸附实验（ELISA）测定3-硝基酪氨酸.采用独立t检验、x2检验、logistic回归分析进行统计学处理.结果 Logistic回归分析发现糖尿病病程、HbA1c、OASHS均是DPN患病与否的独立相关因素（OR=1.12、2.93、3.54,P＜0.05）,糖尿病程、HbA1c、收缩压、OASHS均是DN患病与否的独立相关因素（OR=1.11、3.23、1.67、9.58,P＜0.05）,糖尿病病程、HbA1c、OSAHS是DR患病与否的独立相关因素（OR=1.17、2.89、2.54,P＜0.05）.OSAHS组血浆3-硝基酪氨酸高于非OSAHS组[（121.6±9.3）比（87.5 ±9.1） nmol/L,t=4.36,P＜0.05].结论 T2DM患者中OSAHS与糖尿病微血管病变存在独立相关性.     

玻璃体切除治疗糖尿病视网膜病变

玻璃体切除治疗糖尿病视网膜病变济南市第二人民医院（２００００１）王玉，卢信义糖尿病患者失明的主要原因是增殖性糖尿病性视网膜病变（ＰＤＲ）合并严重玻璃体出血、牵引性视网膜脱离和新生血管性青光眼等并发症。据Ｅｔｄｒｓ，报道。尽管对此进行了全视网膜光凝治疗...     

FPG等三项指标和糖尿病并发CHF患者心功能的关系

目的 探讨入院空腹血糖（fasting plasma glucose, FPG）、糖化血红蛋白（HbA1c）、C肽水平及是否并发糖尿病与慢性心力衰竭（CHF）患者心功能的关系。 方法 选取健康体检者100例作为对照组。选取CHF患者235例,划分为非糖尿病组（n=143）与糖尿病组（n=92）,比较非糖尿病组与糖尿病组心功能NYHA分级与左心室射血分数（LVEF）,比较CHF患者不同组别同组NYHA分级的FPG、HbA1c、C肽水平;应用Pearson相关性及多元线性回归分析CHF患者临床参数与LVEF的关系。 结果 三组一般资料差异无统计学意义;与对照组比较,非糖尿病组的BMI升高（P<0.05）,HbA1和c肽升高（P<0.01）,糖尿病组的体质量指数（BMI）、收缩压、FPG、HbA1c、C肽升高（P<0.01）;与非糖尿病组相比,糖尿病组BMI升高（P<0.05）,收缩压、FPG、C肽明显升高（P<0.01）。与非糖尿病组比较的秩和检验结果为,糖尿病组NYHA心功能分级整体更高（P<0.05）。非糖尿病组左心室射血分数LVEF水平为（48±8）%,糖尿病组LVEF水平为（43±8）%,非糖尿病组LVEF水平明显高于糖尿病组,差异具有统计学意义（P<0.01）。NYHA不同级的FPG、HbA1c、C肽水平比较存在显著差异,NYHA Ⅱ级 结论 非糖尿病及糖尿病CHF患者的FPG、HbA1c及C肽水平均有所升高,三项指标与心力衰竭严重程度存在关联性。     

糖尿病肾病患者血清血管内皮生长因子和血管生成素-2的测定及临床意义

目的探讨糖尿病肾病患者血清血管内皮生长因子(VEGF)及血管生成素(Ang)-2的水平变化及其临床意义。方法选取糖尿病患者68例,其中糖尿病非肾病(DM1)26例,糖尿病肾病42例,按照尿微量白蛋白排泄率(UAER)将其分为微量蛋白尿组(DM2)24例及大量蛋白尿组(DM3)18例,对照组20例,分别测定患者VEGF、Ang-2及糖化皿红蛋白(HbA1c)水平。结果各DM组之间HbA1c水平无明显差异,各组患者之间血清VEGF及Ang-2水平有显著性差异,均高于对照组(P<0.05);DM2较DM1组及DM3较DM2组患者血清VEGF及Ang-2明显升高(P<0.05)。结论血清VEGF及Ang-2参与了糖尿病肾病的发生及发展,其水平与糖尿病肾病严重程度呈正相关,血清VEGF与Ang-2水平呈正相关。     

血浆甘丙肽水平对2型糖尿病性视网膜病变的诊断价值

目的:探讨血浆甘丙肽水平与2型糖尿病性视网膜病变的相关性及诊断价值。方法:245例2型糖尿病患者按照眼底检查结果分为2型糖尿病无视网膜病变组(NDR组)95例,2型糖尿病非增殖性视网膜病变组(NPDR组)78例和2型糖尿病增殖性视网膜病变组(PDR组)72例,另选择65例同期体检中心体检的健康人群作为对照组,统计4组受试对象临床资料,常规检查血糖、血脂等临床指标,酶联免疫吸附测定法检测血浆甘丙肽水平。Logistic回归分析影响NPDR和PDR的危险因素,利用受试者工作曲线(ROC)预测甘丙肽对NPDR或PDR的诊断价值。结果:与对照组比较,NDR组、NPDR组、PDR组收缩压(SBP)、舒张压(FBG)、糖化血红蛋白(HbA1c)、总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、高敏C反应蛋白(Hs-CRP)、胰岛素抵抗指数(HOMA-IR)、血浆甘丙肽明显升高,高密度脂蛋白胆固醇(HDL-C)明显降低,差异有统计学意义(P0.05)。与NDR组比较,NPDR组、PDR组糖尿病病程、SBP、HOMA-IR、Hs-CRP、血浆甘丙肽明显升高,差异有统计学意义(P0.05)。与NPDR组比较,PDR组糖尿病病程、Hs-CRP、血浆甘丙肽明显升高,差异有统计学意义(P0.05)。NPDR和PDR患者血浆甘丙肽与糖尿病病程、FBG、HbA1c、TC、HOMA-IR和Hs-CRP呈正相关(均P0.05)。Logistic回归分析显示,HbA1c、HOMA-IR、Hs-CRP、甘丙肽水平是影响NPDR的独立危险因素;糖尿病病程、HbA1c、HOMA-IR、Hs-CRP、甘丙肽水平是影响PDR的独立危险因素(均P0.05)。甘丙肽诊断NPDR的最佳临界值为21.94ng/L,敏感度为72.0%,特异度为91.6%,ROC曲线下面积(AUC)为0.894(95%CI:0.838~0.936,P0.05)。甘丙肽诊断PDR的最佳临界值为24.92ng/L,敏感度为69.4%,特异度为86.1%,AUC为0.835(95%CI:0.764~0.892,P0.05)。结论:血浆甘丙肽是影响NPDR和PDR的独立危险因素,通过检测血浆甘丙肽水平能够为诊断NPDR和PDR提供参考。     

脂蛋白（a）与2型糖尿病微血管并发症关系探讨

对122例T2DM患者依微血管并发症分为有糖尿病肾病（DN）、有糖尿病视网膜病变（DR）、有DN及DR、无DN和DR4组,并进行Lp（a）、HbA1c、TC、TG、HDL—ch、LDL—ch测定。结果T2DM有DN组Lp（a）、TC、TG、HbA1c、LDL—ch值均显著高于无DN和DR组,T2DM有DR组Lp（a）、TC、TG、HbA1c、LDL—ch值均显著高于无微血管并发症组,2型糖尿病有糖尿病肾病及视网膜病变组Lp（a）、TC、TG、HbA1c、LDL—ch值均显著高于无微血管并发症组,高浓度的Lp（a）与糖尿病微血管并发症有密切关系。结论T2DM患者血清Lp（a）升高可能是微血管病变的重要的危险因素。     

2型糖尿病患者HbA1c水平与糖尿病视网膜病变DR分期的相关性

目的探讨2型糖尿病患者HbA1c水平与糖尿病视网膜病变DR分期的相关性。方法选取2019年11月—2020年8月就诊于承德市中心医院内分泌科,并诊断为2型糖尿病的患者265例,根据眼底检查结果分为非糖尿病视网膜病变(NDR)组(n=156)及糖尿病视网膜病变(DR)组(n=109)。收集两组患者的临床资料包括性别、年龄、糖尿病病程、吸烟史、随机血糖、糖化血红蛋白、血脂、25-羟基维生素D、甲状旁腺激素等。为进一步分析将DR组患者根据HbA1c水平分为两个亚组:HbA1c<10%组;HbA1c≥10%组;比较HbA1c水平与糖尿病视网膜病变DR分期的相关性。结果与NDR组比较,DR组HbA1c水平显著升高[(8.83±1.98)%vs(9.35±1.87)%],差异有统计学意义(P<0.05)。多元Logistic回归分析提示糖尿病病程、HbA1c水平与2型糖尿病患者发生糖尿病视网膜病变独立相关(OR=1.174,95%CI:1.111~1.124;OR=1.234,95%CI:1.021~1.492,P<0.05)。亚组分析结果表明,HbA1c≥10%组(n=35)增殖期(PDR)者较HbA1c<10%组(n=74)明显增多,差异有统计学意义(P<0.05)。结论HbA1c水平与2型糖尿病患者并发糖尿病视网膜病变独立相关。     

中国人群平均血糖与糖化血红蛋白转换关系的初步分析

目的 采用动态血糖监测（CGM）技术探讨不同糖代谢人群24 h平均血糖水平（MBG）与糖化血红蛋白（HbA1c）的关系,并初步建立不同HbA1c水平其相对应的MBG值.方法 选取2007年8月至2010年1月于上海交通大学附属第六人民医院门诊及病房进行口服葡萄糖耐量试验（OGTT）的受试者318人,其中正常糖调节组115名、糖调节受损组57例、新诊断2型糖尿病患者组146例.糖尿病、糖调节受损的诊断采用2003年美国糖尿病学会（ADA）糖尿病诊断标准.测量各组生化指标,并行OGTT,测定糖负荷后2 h血糖（2 h PG）.采用CGM系统估算MBG水平,高压液相法测定HbA1c水平,分析MBG与HbA1c间的关系.统计学采用单因素ANOVA方差分析、Kruskal-Wallis检验、χ^2检验、Spearman相关分析及线性模型进行数据统计.结果 318例研究对象中总体HbA1c水平为（6.6±1.5）%,MBG水平为（7.3±2.3）mmol/L.（2）MBG与HbA1c呈显著正相关（r=0.848,P〈0.01）,其回归方程为MBG=1.252×HbA1c-0.992（R^2= 0.718,P〈0.01）,即HbA1c每升高1%,MBG相应升高1.252 mmol/L.HbA1c=6.5%时,对应的MBG值为7.1 mmol/L.HbA1c=7.0%时,对应的MBG值为7.8 mmol/L.（3）仅包括146例新诊断2型糖尿病患者的MBG和HbA1c之间的关系与总人群的结果一致（r=0.788,P〈0.01）,线性回归方程为MBG=1.255×HbA1c-0.886（R2=0.621,P〈0.01）.当HbA1c= 6.5%时,MBG对应值为7.3 mmol/L.HbA1c=7.0%时,对应的MBG值为7.9 mmol/L.结论 初步建立了各HbA1c水平其相应的MBG值,为深入开展中国人群平均血糖与HbA1c转换关系研究提供了线索.     

Inflammatory cytokines in vitreous fluid and serum of patients with diabetic vitreoretinopathy

To determine whether inflammatory cytokines are increased in proliferative diabetic retinopathy. We measured concentrations of interleukin-6, 8 (IL-6, 8) and tumor necrosis factor (TNF)-alpha by enzyme-linked immunosorbent assay (ELISA) in vitreous and serum from 47 patients with proliferative diabetic retinopathy and 21 patients with vitreous noninflammatory retinopathies. Vitreous concentration of IL-6 were 64.7+/-12.8 pg/ml in proliferative diabetic retinopathy, much greater (P<.005) than in noninflammatory retinopathy (2.8+/-4.5 pg/ml). Amounts of IL-8 in vitreous fluid also were greater in proliferative retinopathy than in noninflammatory retinopathy (34.0+/-11.5 vs. 6.1+/-2.0 pg/ml, P<.005). Concentrations of TNF-alpha in vitreous fluid were not statistically different in proliferative retinopathy from those in noninflammatory retinopathy. In sera, concentrations of IL-6 and IL-8 were not different between proliferative and noninflammatory retinopathy. However, serum TNF-alpha was much greater in proliferative retinopathy than in noninflammatory retinopathy (0.81+/-0.72 vs. 0.09+/-0.00 pg/ml, P<.001). Elevated TNF-alpha in serum then may be diagnostically useful in proliferative diabetic retinopathy. And inflammatory cytokines in vitreous may be pathogenically important in this concentration.     

老年人非外伤性玻璃体大量积血的病因分析

目的探讨老年人非外伤性玻璃体大量积血的病因. 方法对非外伤性玻璃体大量积血的老年患者81例83只眼的病因资料进行总结分析. 结果 81例中,视网膜静脉阻塞导致玻璃体大量积血的患者最多,33例（40.7%）;其次,为增殖型糖尿病性视网膜病变患者31例（38.3%）;渗出型老年性黄斑变性患者10例（12.4%）.视网膜静脉阻塞患者中,玻璃体大量积血迟发于视网膜静脉阻塞的时间间隔≥3个月为21只眼（63.6%）,眼底检查均发现新生血管;＜3个月者为9只眼（27.3%）,眼底检查未发现新生血管. 结论视网膜静脉阻塞、增殖型糖尿病性视网膜病变和渗出型老年性黄斑变性是老年人非外伤性玻璃体大量积血的主要病因.眼底新生血管的形成、破裂和出血是老年人非外伤性玻璃体大量积血的主要原因.     

Decreased angiogenin concentration in vitreous and serum in proliferative diabetic retinopathy

Diabetic retinopathy is the most common cause of vision loss in young adults in developed countries. The disease therapy with anti-vascular endothelial growth factor (VEGF) agents gives some positive results, but is associated with retinal ischemia and vasoconstriction. Therefore, determination of factors involved in the physiological and pathological angiogenesis in the diabetic eye is of great importance for understanding of the pathogenesis of diabetic retinopathy and its effective treatment.Previously, we found that diabetic patients were characterized by increased serum concentration of VEGF, but decreased levels of other proangiogenic factor—angiogenin. The involvement of VEGF in pathogenesis of diabetic retinopathy is well established, but there is lack of data regarding angiogenin in retinopathy. Therefore, in the present study we measured angiogenin concentration in vitreous and serum samples of the patients with type 1 diabetes to determine its role in diabetic retinopathy. In addition, in each time, we compared the level of angiogenin with level of VEGF as a known factor involved in the pathogenesis of the disease.Angiogenin was found to be significantly more abundant in serum than in vitreous in both diabetic groups. In addition, patients with retinopathy had twofold lower vitreous angiogenin levels than diabetic individuals without complications. On the contrary, vitreous concentration of VEGF was dramatically increased only in participants with retinopathy. Patients without diabetic complications had significantly lower VEGF levels in vitreous than in serum and were characterized by high local and systemic concentration of angiogenin.These data suggest a local imbalance between two proangiogenic factors—VEGF and angiogenin in retinopathy. Low vitreous concentration of angiogenin in diabetic patients suggests that this factor is not responsible for pathological neovascularization in diabetic eye. Further studies will elucidate if angiogenin can be used to improve the insufficient angiogenesis in diabetes and prevent retinal ischemia after retinopathy treatment with anti-VEGF agents.     

Predictors of postoperative bleeding after vitrectomy for vitreous hemorrhage in patients with diabetic retinopathy

Aims/Introduction

To clarify the association between perioperative variables and postoperative bleeding in pars plana vitrectomy for vitreous hemorrhage in diabetic retinopathy.

Materials and Methods

The present retrospective study enrolled 72 eyes of 64 patients who were admitted to Osaka University Hospital between April 2010 and March 2014, and underwent vitrectomy for vitreous hemorrhage as a result of diabetic retinopathy.

Results

Postoperative bleeding developed in 12 eyes. Using binomial logistic regression analysis, we found that the duration of operation was the only significant variable associated with postoperative bleeding within 12 weeks after vitrectomy. Furthermore, Poisson regression analysis identified fasting blood glucose just before vitrectomy, no treatment with antiplatelet drugs and treatment with antihypertensive drugs, as well as duration of operation, to be significantly associated with the frequency of bleeding within 52 weeks after vitrectomy.

Conclusions

Long duration of operation can be used to predict bleeding within both 12 and 52 weeks after vitrectomy. In addition, fasting blood glucose just before vitrectomy, no treatment with antiplatelet drugs and treatment with antihypertensive drugs might be risk factors for postoperative bleeding up to 1 year after vitrectomy.     

Angiogenesis regulatory factors in the vitreous from patients with proliferative diabetic retinopathy

We determined the levels of the endogenous angiogenesis inhibitors soluble vascular endothelial growth factor receptor-1 (sVEGFR-1), thrombospondin (TSP)-1 and TSP-2 in the vitreous fluid from patients with proliferative diabetic retinopathy (PDR) and correlated their levels with clinical disease activity and the levels of vascular endothelial growth factor (VEGF). Vitreous samples from 30 PDR and 25 nondiabetic patients were studied by enzyme-linked immunosorbent assay. TSP-1 was not detected. VEGF and TSP-2 levels were significantly higher in PDR with active neovascularization compared with inactive PDR and nondiabetic patients (P < 0.001 for both comparisons). VEGF, sVEGFR-1 and TSP-2 levels were significantly higher in PDR with hemorrhage compared with PDR without hemorrhage and nondiabetic patients (P = 0.0063; 0.0144; <0.001, respectively). VEGF and sVEGFR-1 levels were significantly higher in PDR without traction retinal detachment (TRD) compared with PDR with TRD and nondiabetic patients (P = 0.038; 0.022, respectively). TSP-2 levels were significantly higher in PDR with TRD compared with PDR without TRD and nondiabetic patients (P < 0.001). There was a significant correlation between levels of VEGF and sVEGFR-1 (r = 0.427, P = 0.038). Our findings suggest that upregulation of sVEGFR-1 and TSP-2 may be a protective mechanism against progression of angiogenesis associated with PDR. TSP-2 might be associated with TRD.     

Angiopoietic factors and retinopathy in pregnancies complicated with Type 1 diabetes.

AIMS: To evaluate the role of systemic angiopoietic factors in the progression of diabetic retinopathy during pregnancy. METHODS: In a prospective study of 26 pregnant women with diabetes and eight non-diabetic pregnant women, retinopathy was graded from fundus photographs. Plasma levels of angiopoietin-1, angiopoietin-2, human vascular endothelial growth factor A (hVEGF-A), and total soluble receptor of vascular endothelial growth factor (sVEGF) receptor-1 were measured during the first and third trimester and 3 months postpartum. RESULTS: In diabetic women, levels of angiopoietin-2 were 26.5 ng/ml (12.1-47.7) (median and range) during the first trimester, 2.9 ng/ml (0.6-3.5) during the third trimester, and 0.5 ng/ml (0.3-0.7) 3 months postpartum, compared with 44.3 (38.3-61.9), 5.7 (3.1-8.4) and 0.9 (0.6-4.9) ng/ml, respectively, in non-diabetic women (P = 0.002 between groups). Levels of angiopoietin-1 and sVEGF receptor-1 did not differ between the groups. Postpartum hVEGF-A levels were lowest in women with progression of retinopathy. In logistic regression analyses, progression of retinopathy during pregnancy was not explained by the levels of the angiopoietic factors. CONCLUSIONS: The circulating levels of angiopoietic factors in pregnant diabetic women were either lower than (Ang-2) or similar to (Ang-1, hVEGF-A, VEGFR-1) those levels observed in non-diabetic pregnant women. The levels of angiopoietic factors measured here appear not to be connected with the progression of retinopathy during pregnancy.     

Increased vitreous concentrations of human hepatocyte growth factor in proliferative diabetic retinopathy

Human hepatocyte GF (hHGF) has strong neoangiogenesis activity. The present study was designed to investigate the possible involvement of hHGF in neovascularization in proliferative diabetic retinopathy (PDR) by measuring vitreous hHGF concentrations. The mean vitreous hHGF concentration was higher in subjects with PDR (5.70 +/- 0.68 ng/mL, n = 33) than in nondiabetic control subjects (1.50 +/- 0.20 ng/mL, n = 18, P < 0.01), nondiabetic subjects with proliferative vitreoretinopathy (3.31 +/- 0.57 ng//mL, n = 10, P < 0.05), or diabetic subjects without PDR (1.29 +/- 0.28 ng/mL, n = 8, P < 0.01). PDR subjects with neovascularization of iris, which suggests advanced retinal ischemia, showed a higher mean vitreous hHGF concentration than those without iridal neovascularization [7.33 +/- 1.16 ng/mL (n = 14) vs. 4.49 +/- 0.72 ng/mL (n = 19), P < 0.05]. The mean vitreous hHGF concentration was higher in PDR subjects with retinal neovascularization at the optic disc than in those with neovascularization elsewhere [7.3 +/- 1.1 ng/mL (n = 15) vs. 4.4 +/- 0.7 ng/mL (n = 18), P < 0.05]. Our results indicate that vitreous hHGF may play a role in retinal neovascularization in PDR.     

Increased levels of platelet-derived growth factor in vitreous fluid of patients with proliferative diabetic retinopathy.

It is generally accepted that growth factors play an important role in the pathogenesis of proliferative diabetic retinopathy. Since platelet-derived growth factor AB (PDGF AB) is known to be involved in many angiogenetic and proliferative processes, it was the aim of our study to elucidate the role of PDGF AB in the angiogenetic process in proliferative diabetic retinopathy. We measured PDGF AB concentrations in the vitreous of 23 patients with proliferative diabetic retinopathy, 4 of them with additional rubeosis iridis as an indicator of very high vasoproliferative activity. Control measurements were done in 19 patients without diabetic or ischemic eye diseases and also in 4 non-diabetic patients with ischemic proliferative retinopathy with rubeosis iridis. To exclude PDGF remnants in the vitreous due to vitreous bleeding we additionally measured platelet factor 4 concentrations as a stable marker of activated thrombocytes in the vitreous. Results: Significantly elevated concentrations of PDGF AB were found in the vitreous of patients with proliferative diabetic retinopathy, with higher levels in individuals with additional rubeosis iridis compared to controls. However, concentrations of PDGF AB were also elevated in ischemic non-diabetic retinopathy, supporting the concept that ischemia might be a strong stimulator of growth factor production in the retina. Platelet factor 4 was not detectable in any of the vitreous samples included in the study. In summary, our results indicate that the growth factor PDGF plays an important role in the pathogenesis of proliferative diabetic retinopathy, probably in synergistic action with other growth factors like IGF I, IGF II, VEGF and TNF alpha.