Chello Massimo, Spadaccio Cristiano, Lusini Mario, Covino Elvio, Blarzino Carla, De Marco Federico, Di Domenico Fabio, Coccia Raffaella
Department of Cardiovascular Sciences, University Campus Bio Medico of Rome, Rome, Italy.
Diabetes Metab Res Rev. 2009 Jul;25(5):420-6. doi: 10.1002/dmrr.966.
Diabetic patients exhibit an increased risk of saphenous graft occlusion after coronary bypass. Advanced glycation end products (AGEs) are ubiquitous signalling proteins that are associated with vascular and neurological complication of diabetes. The aim of this study is to verify whether AGE levels may promote endothelial cell alterations responsible for vein graft failure.
Segments of saphenous vein were obtained from both normal people and diabetic patients (HbA(1c) < 6.0%) at the time of coronary surgery. Cultured endothelial cells were incubated in the absence/presence of AGEs (2 and 20 microM), and mRNA and protein for both receptor of AGEs (RAGE) and peroxisome proliferator-activated receptors-gamma (PPAR-gamma) were analysed by real-time polymerised chain reaction (PCR) and Western blot analysis. In the same fashion, the cell release of reactive oxygen species (ROS) was estimated in the absence/presence of AGEs by spectrofluorimetric analysis. Finally, neutrophil-endothelial adhesion was evaluated in saphenous vein segments with and without the addition of AGEs.
AGEs activated in a dose-dependent manner the expression of RAGE and inhibited PPAR-gamma expression in endothelial cells as testified by both reverse transcription-PCR (RT-PCR) and Western blot analysis. Stimulation of cultured endothelial cells with AGEs significantly enhanced intracellular ROS formation in a dose-dependent manner. Finally, neutrophil-endothelial adhesion was significantly increased after incubation of control veins with AGEs.
These findings indicate that even in diabetic patients with HbA(1c) < 6.0%, elevated serum levels of AGE determine a sort of a pro-thrombotic state, providing a common mechanism that could explain the increased rate of vein graft occlusion in this population.
糖尿病患者冠状动脉搭桥术后大隐静脉移植物闭塞风险增加。晚期糖基化终末产物（AGEs）是普遍存在的信号蛋白，与糖尿病的血管和神经并发症相关。本研究的目的是验证AGE水平是否会促进导致静脉移植物失败的内皮细胞改变。
在冠状动脉手术时从正常人和糖尿病患者（糖化血红蛋白[HbA(1c)]<6.0%）获取大隐静脉段。将培养的内皮细胞在有无AGEs（2和20微摩尔）的情况下孵育，通过实时聚合酶链反应（PCR）和蛋白质印迹分析来检测AGEs受体（RAGE）和过氧化物酶体增殖物激活受体γ（PPAR-γ）的mRNA和蛋白质。同样地，通过荧光分光光度分析在有无AGEs的情况下估计细胞活性氧（ROS）的释放。最后，评估添加和不添加AGEs的大隐静脉段中的中性粒细胞-内皮细胞黏附情况。
逆转录-PCR（RT-PCR）和蛋白质印迹分析均证实，AGEs以剂量依赖方式激活内皮细胞中RAGE的表达并抑制PPAR-γ的表达。用AGEs刺激培养的内皮细胞以剂量依赖方式显著增强细胞内ROS的形成。最后，用AGEs孵育对照静脉后，中性粒细胞-内皮细胞黏附显著增加。
这些发现表明，即使在糖化血红蛋白[HbA(1c)]<6.0%的糖尿病患者中，血清AGE水平升高也会导致一种促血栓形成状态，提供了一种可以解释该人群中静脉移植物闭塞率增加的共同机制。
