冠心病患者血清晚期糖基化终产物Nε-羧甲基赖氨酸含量的变化

目的 观察冠心病患者血清晚期糖基化终产物(AGE)Nε-羧甲基赖氨酸(CML)的水平.方法 采用抗戚蓝蛋白晚期糖基化终产物(KLH-AGE)抗体竞争ELISA法,对33例冠心病患者、14例单纯高血压患者及38名正常人血清中CML进行定量观察.结果 33例冠心病患者血清中均测得CML,正常对照组中仅3名血清CML含量＞0.1 mg/L,两组比较差异有极显著性意义(P＜0.001).合并高血压的冠心病患者血清CML水平为(0.92±0.61)mg/L,较单纯高血压[(0.23±0.16)mg/L]或单纯冠心病[(0.44±0.47)mg/L]患者明显增高(P＜0.01,P＜0.05).不合并糖尿病的冠心病患者和合并糖尿病的冠心病患者血清CML水平无显著差异.结论 冠心病患者血清CML水平明显增高,提示机体内晚期糖基化终产物的产生在冠状动脉粥样硬化的形成机制中可能起一定的作用.血清CML含量可作为冠心病患者晚期糖基化反应水平的生物学指标.     

晚期糖基化终末产物对心血管损伤的机制及防治策略

晚期糖基化终末产物（advanced glycosylation end products, AGEs）是糖酮或醛基与蛋白、脂质、氨基酸的自由氨基经不可逆反应所形成的物质，是非酶糖基化反应的最终产物。研究发现在动脉硬化、心肌舒张异常及内皮功能紊乱等心血管疾病中都出现AGEs水平的增加，并且抑制AGEs的产生或作用具有心血管保护作用。因此，AGEs可以作为防治心血管疾病的一个潜在靶点。本文重点综述了AGEs的来源、心血管损伤机制及防治策略。     

外源晚期糖基化终产物对大鼠脾脏组织结构的影响

目的探讨外源晚期糖基化终产物(AGEs)对大鼠脾脏组织结构的影响。方法采用大鼠血清蛋白制备外源AGEs,进行质量检测。SD大鼠经尾静脉注射外源AGEs,检测脾脏组织结构的变化,并与青年对照组和老龄对照组比较。结果 AGEs组大鼠脾脏白髓数量减少且形态不规则,淋巴细胞数量少,红、白髓区消失,红髓区域明显扩大。超微结构见核固缩、核破裂,细胞高度变形呈不规则锯齿状,细胞器肿胀,染色质边集,线粒体结构异常,线粒体嵴断裂,并有严重肿胀、空泡化。结论外源AGEs可诱导大鼠脾脏组织结构衰老样变。     

晚期糖基化终产物对大鼠免疫器官抗氧化系统的影响

目的 探讨外源性晚期糖基化终产物(AGEs)对大鼠免疫器官氧化/抗氧化系统的影响.方法 采用雌性SD大鼠,外源性AGEs干预采用尾静脉注射法,采用荧光光谱法检测血清、胸腺、脾脏AGEs含量,并检测胸腺、脾脏MDA含量、SOD和GSH-Px活性,并与青年对照组和老龄对照组比较.结果 AGEs组大鼠血清、胸腺、脾脏AGEs及MDA水平较青年对照组显著升高,而SOD、GSH-Px活性则显著下降,以上结果与老龄大鼠相似.结论 外源AGEs可能通过破坏大鼠免疫器官氧化与抗氧化系统平衡诱导免疫衰老.     

晚期糖基化终产物直接病理作用机制研究进展

越来越多的研究表明，晚期糖基化终产物与糖尿病并发症的发生、发展以及机体老化都有着密不可分的联系。本文概述了晚期糖基化终产物的直接病理作用机制，包括改变晶状体、胶原等蛋白质的结构，修饰低密度脂蛋白、高密度脂蛋白等脂质，修饰核酸，通过晚期糖基化终产物结合蛋白介导等。     

晚期糖基化终产物诱导血管内皮细胞骨架形态改变的机制

目的研究晚期糖基化终产物修饰蛋白对内皮细胞细胞骨架肌动蛋白的形态学影响及特异的糖基化终产物受体和氧化应激在此病理过程中的作用。方法用不同浓度的糖基化终产物修饰人血清白蛋白与人脐静脉内皮细胞株ECV304在体外共同培养不同时间，并设立对照组进行比较，采用免疫荧光染色法显示细胞骨架的形态学改变。结果与对照组相比，糖基化终产物修饰人血清白蛋白以时间和剂量依赖的方式影响内皮细胞骨架肌动蛋白聚合丝状和可溶性单体（或球状）形态的改变。随着糖基化终产物修饰人血清白蛋白作用浓度和时间的增加，丝状肌动蛋白所形成的外周致密带边缘出现锯齿样断裂，趋于变细崩解消散，最终形成由非极性单行排列的肌动蛋白丝组成的应力纤维。可溶性单体表现为向细胞浆和胞膜移位，胞浆区出现点状和丝状染色，细胞间距离明显增大。可溶性糖基化终产物受体的抗体和烟酰胺腺嘌呤二核苷酸磷酸盐氧化酶抑制剂均可阻断糖基化终产物对细胞骨架的影响。结论糖基化终产物修饰蛋白对细胞骨架的影响是通过与内皮细胞上的糖基化终产物受体结合并引起细胞内的氧化应激所介导的，这一作用可能与糖基化终产物所致血管通透性升高有关。     

糖基化终产物引起晚期内皮祖细胞功能障碍

目的观察与糖尿病患者血清浓度类似的糖基化终产物修饰的牛血清白蛋白对体外培养脐血来源晚期内皮祖细胞功能的影响并探讨可能机制。方法密度梯度离心法分离脐血中单个核细胞,用差速贴壁法分离、培养晚期内皮祖细胞。流式细胞术、免疫细胞化学染色及荧光标记的乙酰化低密度脂蛋白、植物凝集素被用于鉴定培养的细胞。将晚期糖基化修饰的牛血清白蛋白与晚期内皮祖细胞共同培养24h后,利用噻唑蓝法检测细胞的增殖能力,AnnexinV/PI双染法流式细胞术检测细胞凋亡;Boyden小室法检测血管内皮生长因子趋化的细胞迁移;ECMatirx-gel检测形成毛细血管样网状结构的能力。利用逆转录聚合酶链反应、蛋白免疫印迹法测定糖基化终产物受体mRNA和蛋白表达水平。结果脐血单个核细胞在体外培养过程中先后出现两种细胞:第5～7天出现集落样生长细胞,扩增不明显,存在14天左右即消失,这类细胞被称为"早期内皮祖细胞";10～15天时,逐渐出现20～50个细胞组成的细胞簇,1～3天即可形成大于500个细胞簇,细胞呈铺路石样,可传代,大于95%的细胞免疫表型为CD45-/CD146+/CD105+,表达内皮细胞特有的vWF因子,可摄取乙酰化低密度脂蛋白并可与荆豆凝集素1结合,这类细胞被称为"晚期内皮祖细胞"。50～400mg/L晚期糖基化修饰的牛血清白蛋白与晚期内皮祖细胞共培养24h后,与对照组相比,细胞的增殖能力未见明显变化(P0.05)。当晚期糖基化修饰的牛血清白蛋白浓度大于100mg/L时,与对照组相比,晚期内皮祖细胞的凋亡增加(P0.05)、血管内皮生长因子趋化的迁移以及在ECMatirx-gel上形成新生血管的能力下降(P0.05),糖基化终产物受体mRNA和蛋白表达均增加(P0.05)。结论糖基化终产物通过促进凋亡、抑制迁移及体外形成新生血管的能力引起晚期内皮祖细胞功能障碍,这些影响可能与糖基化终产物上调晚期内皮祖细胞上糖基化终产物受体表达有关。     

N^ε—羧甲基赖氨酸是慢性血液透析病人晚期糖基化终产物的天然 …

鉴定导致长期血液透析病人淀粉样变等并发症的可能致病原－晚期糖基化终产物的分子结构。方法采用对氧化，糖基化物－Ｎε羧甲基赖氨特异的抗体对ＨＤ病人血浆和淀粉样沉积物中的ＣＭＬ进行定量观察。     

晚期糖基化终产物引起的RhoA和ROCK在人皮肤微血管内皮细胞的分布变化

目的观察在晚期糖基化终产物修饰的人血清白蛋白作用下,小G蛋白RhoA及其激活的激酶ROCK在人微血管内皮细胞中分布的变化。方法培养人皮肤微血管内皮细胞株,分别以糖基化修饰的人血清白蛋白(AGE-HSA)处理不同的浓度和时间,用免疫荧光染色法、激光共聚焦显微镜观察RhoA和磷酸化ROCK在细胞中的分布变化;并用活性型RhoA L63或失活型的RhoA N19转染细胞后再给予AGE-HSA刺激,观察磷酸化ROCK细胞内分布的变化。结果 AGE-HSA刺激可以导致RhoA在胞浆中分布增多,其变化随着AGE-HSA作用时间的延长和剂量的增加更加明显。RhoA的下游激酶被活化的磷酸化ROCK在人微血管内皮细胞中的分布与RhoA类似;用失活型RhoAN19先处理细胞后,AGE-HSA介导的ROCK分布变化被抑制。结论晚期糖基化终产物刺激引起小G蛋白RhoA在细胞内分布变化,并导致其下游激酶ROCK磷酸化和定位变化。     

肥胖儿童血清晚期糖基化终产物水平测定及意义

目的探讨肥胖儿童血清晚期糖基化终产物(AGEs)水平的测定及意义。方法采用荧光分光光度计测定30例肥胖伴高血压儿童(肥胖伴高血压组)、30例单纯性肥胖儿童(肥胖组)及30例查体体质量、血压均正常儿童(对照组)血清AGEs水平。结果血清AGEs水平肥胖伴高血压组>肥胖组>对照组,P均<0.05。结论肥胖伴高血压儿童血清AGEs水平明显升高,血清AGEs水平可作为肥胖儿童心血管病初筛的生物学标志。     

冠心病患者血清糖基化终产物水平升高的意义

目的探讨糖基化终产物(AGEs)与冠心病的关系。方法分别运用荧光法和ELISA法测定冠心病患者血清F-AGE和E-AGE水平,并与健康人、糖尿病患者比较。结果35例冠心病患者血清F-AGE和E-AGE水平分别为(10.4±0.6)U/ml和(14.7±1.8)U/ml,明显高于健康人［分别为(7.5±0.2)U/ml,P<0.01和（8.6±1.5)U/ml,P<0.0001］;但与糖尿病患者差异无显著性［分别为(11.0±0.3)U/ml,P>0.05和(18.1±1.3)U/ml,P>0.05)］。结论增高的AGEs水平可能与冠心病发病有密切关系。     

Advanced glycation end products induce angiogenesis in vivo

Advanced glycation end products (AGEs) have been thought to participate in diabetic microangiopathy. However, the effects of AGEs on angiogenesis have so far been mainly examined either in vitro or by using cultured cells. In the present study, we have analyzed whether AGEs induce angiogenesis in vivo by using the chorioallantoic membrane (CAM) assay. The CAM assay was carried out in embryonated hen eggs to determine the effects of AGEs. Following generation of AGEs based on bovine serum albumin (BSA), either AGE-BSA or nonglycated BSA was administered to the CAM and their effects on angiogenesis were assessed, together with an inhibitory effect of an anti-AGE antibody against AGE-BSA-induced angiogenesis. The histological features of AGE-induced vascular lumens were examined by immunohistochemical analysis for Factor VIII and smooth muscle alpha-actin. AGE-BSA induced angiogenesis in CAM in a dose- and time-dependent manner. AGE-induced angiogenesis on CAM was neutralized by the anti-AGE antibody. Immunohistochemical analysis demonstrated that AGE-induced vascular lumens were devoid of pericytes. Our data demonstrated that AGEs are an angiogenetic factor and that our system of AGE-induced abnormal vessels in CAMs is useful in further investigations of the mechanism of diabetic retinal angiogenesis and can also be used to provide a therapeutic model for diabetic angiopathy.     

Advanced glycation end products in myocardial reperfusion injury

Advanced glycation end products (AGEs) are associated with cardiovascular diseases. Whether the AGE levels change during myocardial reperfusion injury is currently unknown. The aim of our study was to investigate the dynamics of AGEs in myocardial reperfusion injury and to discuss potential reasons for these changes. The dynamics of AGEs, pentosidine and neopterin in the plasma of patients with acute myocardial infarction (AMI) treated using thrombolysis (n?=?40) were analyzed. In addition, AGEs were measured in patients with open heart surgery (n?=?12) and rabbits with induced AMI (n?=?9). In all three studies of myocardial reperfusion injury, a significant decrease of AGEs was observed (by 26?±?19% in patients with AMI, by 23?±?14% in patients with open heart surgery and by 39?±?10% in rabbits with AMI within 1?day of reperfusion; p?<?0.05 in all studies). In additional studies, an association between lower AGEs and an activated immune system (R ²?=?0.09; p?<?0.01) and fasting (decrease by 38%; p?<?0.01) was shown. AGEs decrease in reperfusion injury of the heart. Indices pointing towards the involvement of immune system activation and fasting are presented. Further studies focusing on the underlying mechanism and on the clinical value of the observed dynamics of AGEs are needed.     

糖尿病大鼠主动脉糖化终产物的免疫组化研究

目的　研究糖尿病时主动脉壁非酶糖化的程度以及非酶糖化机制在糖尿病血管重建和慢性并发症发生发展中的作用。方法　应用抗糖化终产物（ＡＧＥｓ） 多克隆抗体,对糖尿病大鼠和氨基胍治疗后的糖尿病大鼠进行主动脉壁ＡＧＥｓ 的免疫组化研究,计算机图像处理系统定量分析。结果糖尿病时主动脉壁中膜ＡＧＥｓ 的相对面积呈进行性增加,４ 周时其相对面积就显著大于对照组（ Ｐ＜０．０１）,氨基胍治疗４ 周后主动脉壁中膜ＡＧＥｓ 的相对面积较糖尿病组显著降低（ Ｐ＜ ０．０５）,治疗２４周后降低更为明显（Ｐ＜ ０．０１）。结论　主动脉壁ＡＧＥｓ 的免疫组化定量研究能更直观地反映血管组织非酶糖化的程度,非酶糖化是引起血管重建的重要机制之一。     

Advanced glycation end products and advanced oxidation protein products in hemodialyzed patients

Chronic renal failure is associated with increased oxidative and carbonyl stresses that contribute to long-term uremic complications. In our study, we determined two markers of these stresses--AGEs (advanced glycation end products) and AOPP (advanced oxidation protein products)--in chronic hemodialysis patients in order to find out their relationship to the dialysis treatment. Plasmas of 20 hemodialyzed patients treated with modified cellulose membranes were examined at 0 and 15 min and at the end (i.e. after 4 h) of the dialysis session. AGEs were estimated using a spectrofluorometric method (excitation 350 nm, emission 440 nm) and are expressed in AU (arbitrary units)/g protein. AOPP were determined spectrophotometrically (absorbance at 340 nm) and are expressed in chloramine units per gram of protein (micromol/g). AOPP decrease slightly from 0 to 15 min of the dialysis procedure (4.0 +/- 1.5 vs. 3.0 +/- 0.9 micromol/g, p < 0.01). However, they are increased at the end of the session (5.0 +/- 2.1 micromol/l vs. 15 min, p < 0.01, not significant vs. beginning). On the other hand, AGEs decrease continuously from the beginning to the end of the session (mainly in the first minutes of the dialysis) (1.52 +/- 0.34 x 10(4) AU/g at 0 min, 1.39 +/- 0.33 x 10(4) AU/g at 15 min, p < 0.001 vs. beginning, 1.30 +/- 0.33 x 10(4) AU/g at the end, p < 0.001 vs. beginning, not significant vs. 15 min). Neither AGEs nor AOPP correlate with the age of hemodialyzed patients and with the number of years of the dialysis treatment. AOPP correlate with AGEs before the dialysis session (r = 0.62, p < 0.05) but not after the session (r = 0.29, not significant). According to our results, AGEs may serve more as a marker of chronic damage while AOPP may better describe acute oxidative stress during the dialysis treatment.     

Exogenous advanced glycosylation end products induce complex vascular dysfunction in normal animals: a model for diabetic and aging complications.

Advanced glycosylation end products (AGEs) have been implicated in many of the complications of diabetes and normal aging. Markedly elevated vascular tissue and circulating AGEs were linked recently to the accelerated vasculopathy of end-stage diabetic renal disease. To determine the pathogenic role of AGEs in vivo, AGE-modified albumin was administered to healthy nondiabetic rats and rabbits alone or in combination with the AGE-crosslink inhibitor aminoguanidine. Within 2-4 weeks of AGE treatment, the AGE content of aortic tissue samples rose to six times the amount found in controls (P < 0.001). Cotreatment with aminoguanidine limited tissue AGE accumulation to levels two times that of control. AGE administration was associated with a significant increase in vascular permeability, as assessed by 125I label tracer methods. This alteration was absent in animals that received aminoguanidine in addition to AGE. Significant mononuclear cell migratory activity was observed in subendothelial and periarteriolar spaces in various tissues from AGE-treated rats compared to normal cellularity noted in tissues from animals treated with aminoguanidine. Blood pressure studies of AGE-treated rats and rabbits revealed markedly defective vasodilatory responses to acetylcholine and nitroglycerin compared to controls (P < 0.001), consistent with marked NO. inactivation; aminoguanidine treatment significantly prevented this defect. These in vivo data demonstrate directly that AGEs, independent of metabolic or genetic factors, can induce complex vascular alterations resembling those seen in diabetes or aging. AGE administration represents an animal model system for the study of diabetic and aging complications as well as for assessing the efficacy of newly emerging therapies aimed at inhibiting advanced glycosylation.     

Advanced glycation end products induce a prothrombotic phenotype in mice via interaction with platelet CD36

Diabetes mellitus has been associated with platelet hyperreactivity, which plays a central role in the hyperglycemia-related prothrombotic phenotype. The mechanisms responsible for this phenomenon are not established. In the present study, we investigated the role of CD36, a class-B scavenger receptor, in this process. Using both in vitro and in vivo mouse models, we demonstrated direct and specific interactions of platelet CD36 with advanced glycation end products (AGEs) generated under hyperglycemic conditions. AGEs bound to platelet CD36 in a specific and dose-dependent manner, and binding was inhibited by the high-affinity CD36 ligand NO(2)LDL. Cd36-null platelets did not bind AGE. Using diet- and drug-induced mouse models of diabetes, we have shown that cd36-null mice had a delayed time to the formation of occlusive thrombi compared with wild-type (WT) in a FeCl(3)-induced carotid artery injury model. Cd36-null mice had a similar level of hyperglycemia and a similar level of plasma AGEs compared with WT mice under this condition, but WT mice had more AGEs incorporated into thrombi. Mechanistic studies revealed that CD36-dependent JNK2 activation is involved in this prothrombotic pathway. Therefore, the results of the present study couple vascular complications in diabetes mellitus with AGE-CD36-mediated platelet signaling and hyperreactivity.