Advanced glycation end products (AGEs) co-localize with AGE receptors in the retinal vasculature of diabetic and of AGE-infused rats.

Advanced glycation end products (AGEs), formed from the nonenzymatic glycation of proteins and lipids with reducing sugars, have been implicated in many diabetic complications; however, their role in diabetic retinopathy remains largely unknown. Recent studies suggest that the cellular actions of AGEs may be mediated by AGE-specific receptors (AGE-R). We have examined the immunolocalization of AGEs and AGE-R components R1 and R2 in the retinal vasculature at 2, 4, and 8 months after STZ-induced diabetes as well as in nondiabetic rats infused with AGE bovine serum albumin for 2 weeks. Using polyclonal or monoclonal anti-AGE antibodies and polyclonal antibodies to recombinant AGE-R1 and AGE-R2, immunoreactivity (IR) was examined in the complete retinal vascular tree after isolation by trypsin digestion. After 2, 4, and 8 months of diabetes, there was a gradual increase in AGE IR in basement membrane. At 8 months, pericytes, smooth muscle cells, and endothelial cells of the retinal vessels showed dense intracellular AGE IR. AGE epitopes stained most intensely within pericytes and smooth muscle cells but less in basement membrane of AGE-infused rats compared with the diabetic group. Retinas from normal or bovine-serum-albumin-infused rats were largely negative for AGE IR. AGE-R1 and -R2 co-localized strongly with AGEs of vascular endothelial cells, pericytes, and smooth muscle cells of either normal, diabetic, or AGE-infused rat retinas, and this distribution did not vary with each condition. The data indicate that AGEs accumulate as a function of diabetes duration first within the basement membrane and then intracellularly, co-localizing with cellular AGE-Rs. Significant AGE deposits appear within the pericytes after long-term diabetes or acute challenge with AGE infusion conditions associated with pericyte damage. Co-localization of AGEs and AGE-Rs in retinal cells points to possible interactions of pathogenic significance.     

Calcium distribution in aortic smooth muscle cells of deoxycorticosterone-hypertensive rats. A quantitative cytochemical study

The effect of deoxycorticosterone (DOC)-induced hypertension on the calcium content within the aorta was studied before the increase in pressure (one week) and after the pressure had reached hypertensive levels (4 weeks). The volume density of free calcium detected ultrastructurally by pyroantimonate precipitation was quantitated by stereological techniques in aortic smooth muscle cells. An increase in the volume density of electron opaque precipitate was observed in the cytoplasm at one week of DOC treatment when neither the systolic blood pressure, the thickness of the media nor volume fraction of medial smooth muscle as compared to the extracellular space was increased significantly. The total aortic calcium as measured by atomic absorption spectroscopy was not increased at one week. By 4 weeks when the rats were hypertensive, the cytoplasmic free calcium in the smooth muscle cells and the number of peripherally-located cytoplasmic vesicles with precipitate was increased significantly. Total aortic calcium was also increased significantly in the DOC-saline group but not in the DOC group drinking tap water or in the saline drinking controls. An elevation of calcium within the cytoplasm of vascular smooth muscle cells may precede the development of hypertension and play a role in the pathogenesis of the increased blood pressure, increased medial thickness and hypertrophy of the vascular smooth muscle cells.     

小檗碱对糖尿病大鼠血管平滑肌细胞增殖影响研究

目的:观察小檗碱(Berberine)对糖尿病大鼠血管平滑肌细胞(VSMC)增殖影响及对核因子-κB(NF-κB)的影响。方法:采用一次性腹腔注射链脲佐菌素55mg.kg-1诱发糖尿病大鼠模型,取建模成功大鼠胸主动脉中膜血管平滑肌细胞进行培养,倒置显微镜下观察细胞形态,SMA免疫组化染色鉴定细胞,计数法观察细胞的生长曲线,CCK-8法测定小檗碱IC50,共聚焦显微镜下观察小檗碱对VSMC中NF-κB核转移的影响。结果:与正常组对比,糖尿病组VSMC生长速度快,小檗碱能明显抑制糖尿病血管平滑肌细胞增殖,IC50为6.001±0.853μmol.L-1,而对正常大鼠VSMC增殖的IC50为18.229±0.434μmol.L-1(P<0.05)有剂量依赖性;小檗碱能抑制糖尿病VSMC中NF-κB从胞浆转移到胞核。结论:小檗碱呈剂量依赖性能抑制糖尿病VSMC增殖与NF-κB的核转移。揭示小檗碱可能有抑制糖尿病大血管病变作用,而此作用可能与抑制NF-κB激活有关。     

AGEs介导的糖尿病肾损伤机制及二甲双胍的干预作用

糖尿病肾病(diabetic nephropathy,DN)是糖尿病(diabetes mellitus,DM)的常见的慢性微血管并发症之一。慢性高糖状态下糖基化终末产物(AGEs)形成增加,诱导肾脏氧化应激和内质网应激,参与糖尿病肾病的发生与发展。二甲双胍是目前临床治疗糖尿病的最常用药物之一。越来越多的研究表明,二甲双胍除了最主要的降糖作用外,其尚可抑制AGEs形成和具有抗氧化作用,深入研究AGEs与DN的关系,有助于进一步了解DN的发病机制并对干预其发生和发展具有重要的指导意义。     

Advanced glycation end-products disrupt the blood–brain barrier by stimulating the release of transforming growth factor–β by pericytes and vascular endothelial growth factor and matrix metalloproteinase–2 by endothelial cells in vitro

Diabetic encephalopathy is now accepted as an important complication of diabetes. The breakdown of the blood–brain barrier (BBB) is associated with dementia in patients with type 2 diabetes mellitus (T2DM). The purpose of this study was to identify the possible mechanisms responsible for the disruption of the BBB after exposure to advanced glycation end-products (AGEs). We investigated the effect of AGEs on the basement membrane and the barrier property of the BBB by Western blot analysis, using our newly established lines of human brain microvascular endothelial cell (BMEC), pericytes, and astrocytes. AGEs reduced the expression of claudin-5 in BMECs by increasing the autocrine signaling through vascular endothelial growth factor (VEGF) and matrix metalloproteinase–2 (MMP-2) secreted by the BMECs themselves. Furthermore, AGEs increased the amount of fibronectin in the pericytes through a similar up-regulation of the autocrine transforming growth factor (TGF)–β released by pericytes. These results indicated that AGEs induce basement membrane hypertrophy of the BBB by increasing the degree of autocrine TGF-β signaling by pericytes, and thereby disrupt the BBB through the up-regulation of VEGF and MMP-2 in BMECs under diabetic conditions.     

Endothelial dysfunction and vascular disease

The endothelium can evoke relaxations (dilatations) of the underlying vascular smooth muscle, by releasing vasodilator substances. The best characterized endothelium‐derived relaxing factor (EDRF) is nitric oxide (NO). The endothelial cells also evoke hyperpolarization of the cell membrane of vascular smooth muscle (endothelium‐dependent hyperpolarizations, EDHF‐mediated responses). Endothelium‐dependent relaxations involve both pertussis toxin‐sensitive G_i (e.g. responses to serotonin and thrombin) and pertussis toxin‐insensitive G_q (e.g. adenosine diphosphate and bradykinin) coupling proteins. The release of NO by the endothelial cell can be up‐regulated (e.g. by oestrogens, exercise and dietary factors) and down‐regulated (e.g. oxidative stress, smoking and oxidized low‐density lipoproteins). It is reduced in the course of vascular disease (e.g. diabetes and hypertension). Arteries covered with regenerated endothelium (e.g. following angioplasty) selectively loose the pertussis toxin‐sensitive pathway for NO release which favours vasospasm, thrombosis, penetration of macrophages, cellular growth and the inflammatory reaction leading to atherosclerosis. In addition to the release of NO (and causing endothelium‐dependent hyperpolarizations), endothelial cells also can evoke contraction (constriction) of the underlying vascular smooth muscle cells by releasing endothelium‐derived contracting factor (EDCF). Most endothelium‐dependent acute increases in contractile force are due to the formation of vasoconstrictor prostanoids (endoperoxides and prostacyclin) which activate TP receptors of the vascular smooth muscle cells. EDCF‐mediated responses are exacerbated when the production of NO is impaired (e.g. by oxidative stress, ageing, spontaneous hypertension and diabetes). They contribute to the blunting of endothelium‐dependent vasodilatations in aged subjects and essential hypertensive patients.     

Effects of preventative application of metformin on bile acid metabolism in high fat-fed/streptozotocin-diabetic rats

Objective: This study was designed to investigate the effects of metformin on bile acid in type 2 diabetes mellitus (T2DM). Methods: In this study, we constructed a model of T2DM by a combination of high-fat diet (HFD) and low dose of streptozotocin (STZ) intraperitoneal injection. Blood samples by tail vein and eye angular vein were withdrawn before (time 0) and 30, 60, and 120 minutes after administration of glucose before STZ injection and once a week after diabetes induction, and were analyzed to evaluate the level of the fasting blood glucose and fasting insulin using glucometer. Triglyceride, low density lipoprotein cholesterin, high density lipoprotein cholesterin were detected by automatic biochemical analyzers. Total cholesterol and total bile acid (TBA) were analyzed using ELISA kits. Results: Before STZ injection, the TBA level in HFD group was significantly higher relative to that in standard diet (SD) group and there was a moderate reduction of the TBA level in early intervention (EI) group 6 week after metformin administration comparing with that in HFD group but was still higher than that of SD group. However, after STZ injection, the TBA level was significantly higher in DM rats relative to that in normal control (NC) rats and the TBA level in late intervention (LI) (19.92 μmol/L) and EI rats (42.97 μmol/L) with metformin administration was significantly higher comparing with that in DM rats. Conclusion: The effects of metformin in plasma glucose and lipid metabolism might be associated with bile acid metabolism.     

Endothelial dysfunction and vascular disease – a 30th anniversary update

The endothelium can evoke relaxations of the underlying vascular smooth muscle, by releasing vasodilator substances. The best‐characterized endothelium‐derived relaxing factor (EDRF) is nitric oxide (NO) which activates soluble guanylyl cyclase in the vascular smooth muscle cells, with the production of cyclic guanosine monophosphate (cGMP) initiating relaxation. The endothelial cells also evoke hyperpolarization of the cell membrane of vascular smooth muscle (endothelium‐dependent hyperpolarizations, EDH‐mediated responses). As regards the latter, hydrogen peroxide (H₂O₂) now appears to play a dominant role. Endothelium‐dependent relaxations involve both pertussis toxin‐sensitive G_i (e.g. responses to α₂‐adrenergic agonists, serotonin, and thrombin) and pertussis toxin‐insensitive G_q (e.g. adenosine diphosphate and bradykinin) coupling proteins. New stimulators (e.g. insulin, adiponectin) of the release of EDRFs have emerged. In recent years, evidence has also accumulated, confirming that the release of NO by the endothelial cell can chronically be upregulated (e.g. by oestrogens, exercise and dietary factors) and downregulated (e.g. oxidative stress, smoking, pollution and oxidized low‐density lipoproteins) and that it is reduced with ageing and in the course of vascular disease (e.g. diabetes and hypertension). Arteries covered with regenerated endothelium (e.g. following angioplasty) selectively lose the pertussis toxin‐sensitive pathway for NO release which favours vasospasm, thrombosis, penetration of macrophages, cellular growth and the inflammatory reaction leading to atherosclerosis. In addition to the release of NO (and EDH, in particular those due to H₂O₂), endothelial cells also can evoke contraction of the underlying vascular smooth muscle cells by releasing endothelium‐derived contracting factors. Recent evidence confirms that most endothelium‐dependent acute increases in contractile force are due to the formation of vasoconstrictor prostanoids (endoperoxides and prostacyclin) which activate TP receptors of the vascular smooth muscle cells and that prostacyclin plays a key role in such responses. Endothelium‐dependent contractions are exacerbated when the production of nitric oxide is impaired (e.g. by oxidative stress, ageing, spontaneous hypertension and diabetes). They contribute to the blunting of endothelium‐dependent vasodilatations in aged subjects and essential hypertensive and diabetic patients. In addition, recent data confirm that the release of endothelin‐1 can contribute to endothelial dysfunction and that the peptide appears to be an important contributor to vascular dysfunction. Finally, it has become clear that nitric oxide itself, under certain conditions (e.g. hypoxia), can cause biased activation of soluble guanylyl cyclase leading to the production of cyclic inosine monophosphate (cIMP) rather than cGMP and hence causes contraction rather than relaxation of the underlying vascular smooth muscle.     

Intimal plaque development and oxidative stress in cholesterol-induced atherosclerosis in New Zealand rabbits

Although oxidative stress is well known in atherogenesis, the origin, nature and kinetics of free radicals involved have not been well described till now. Here, we correlated parameters of oxidative stress with cellular components during induction and stabilization of aortic intimal lesions which were induced in rabbits by feeding a cholesterol-enriched diet for 6 weeks and a normal diet for further 68 weeks. Plasma lipids, aortic plaque size and composition (macrophages, smooth muscle cells, oxidized LDL by morphometry), as well as aortic radical production (by luminol-enhanced chemiluminescence and TEMPO-9AC fluorescence) were measured after various time points. The parameters of oxidative stress were correlated with the different cellular components of the aortic plaques. The plaques increased until week 21, no significant regression was found until week 74, plasma cholesterol was maximal at week 6. Macrophages, oxidized LDL and generation of different species of free radicals were increased during plaque development, yet with different time kinetics. Whereas chemiluminescence correlated only weakly with the amount of intimal macrophages, strong correlations were found between TEMPO fluorescence and smooth muscle cells (r = 0.4778, P < 0.001) and between macrophages and oxidized LDL (r = 0.5896, P < 0.0001). Different indicators of oxidative stress were increased during plaque progression and stabilization. However, the various correlations show, that distinct types of reactive species secreted probably from macrophages and smooth muscle cells contribute to oxidative stress in the different phases of plaque development.     

Intimal plaque development and oxidative stress in cholesterol‐induced atherosclerosis in New Zealand rabbits

Although oxidative stress is well known in atherogenesis, the origin, nature and kinetics of free radicals involved have not been well described till now. Here, we correlated parameters of oxidative stress with cellular components during induction and stabilization of aortic intimal lesions which were induced in rabbits by feeding a cholesterol‐enriched diet for 6 weeks and a normal diet for further 68 weeks. Plasma lipids, aortic plaque size and composition (macrophages, smooth muscle cells, oxidized LDL by morphometry), as well as aortic radical production (by luminol‐enhanced chemiluminescence and TEMPO‐9AC fluorescence) were measured after various time points. The parameters of oxidative stress were correlated with the different cellular components of the aortic plaques. The plaques increased until week 21, no significant regression was found until week 74, plasma cholesterol was maximal at week 6. Macrophages, oxidized LDL and generation of different species of free radicals were increased during plaque development, yet with different time kinetics. Whereas chemiluminescence correlated only weakly with the amount of intimal macrophages, strong correlations were found between TEMPO fluorescence and smooth muscle cells (r = 0.4778, P < 0.001) and between macrophages and oxidized LDL (r = 0.5896, P < 0.0001). Different indicators of oxidative stress were increased during plaque progression and stabilization. However, the various correlations show, that distinct types of reactive species secreted probably from macrophages and smooth muscle cells contribute to oxidative stress in the different phases of plaque development.     

Weight reduction ameliorates inflammatory cytokines,adipocytokines and endothelial dysfunction biomarkers among Saudi patients with type 2 diabetes

BackgroundType 2 diabetes mellitus (T2DM) considered as one of the cardiovascular disorders (CVD) principle risk factor as diabetes is associated with abnormal levels of endothelial function, inflammatory and adipocytokines.ObjectiveThe aim of this study was to measure the impact of weight reducing on inflammatory cytokines, adipocytokines and endothelial function biomarkers among obese T2DM patients.MethodsOne-hundred T2DM patients enrolled in the present study; the age range was 35–55 year. Participants shared in this study were enrolled in group (A) received diet control and aerobic exercise on treadmill, while, group (B) had no intervention for 3 months.ResultsThe mean values of body mass index (BMI), tumor necrosis factor -alpha (TNF-α), interleukin-6 (IL-6), leptin, inter-cellular adhesion molecule (ICAM-1), vascular cell adhesion molecule (VCAM-1), E-selectin and plasminogen activator inhibitor-1 activity (PAI-1 activity) were significantly decreased and adiponectin was increased significantly in the training group, however the results of the control group were not significant. Also, there were significant differences between both groups at the end of the study.ConclusionWeight reducing program modulates inflammatory cytokines, adipocytokines and endothelial function biomarkers among obese T2DM patients.     

Expression of Receptors for Advanced Glycation End Products in Peripheral Occlusive Vascular Disease

The cellular interactions of advanced glycation end products (AGEs), which have been hypothesized to contribute to the development of vascular lesions, occur, at least in part, through thei binding to a novel integral membrane protein, the receptor for AGEs (RAGE). Studies of human vascular segments show that endothelial RAGE expression at the antigen and mRNA level was variable and usually at low levels in samples from healthy individuals. In contrast, patients with arange of peripheral occlusive vascular diseases, with or without underlying diabetes, demonstrated prominent enhancement of endothelial RAGE expression. Smooth muscle cells and nerves in the vessel wall showed constitutively high levels of RAGE expression that were unchanged with aging (from 1 to 92 years) or by the presence of vascular disease, These data suggest that RAGE is likely to have ligands other than AGEs, and that multiple factors in addition to AGEs impact on its expression. Taken together, our findings suggest that RAGE may contribute to the pathogenesis of a range of vascular disorders.     

Diabetes mellitus accelerates cartilaginous metaplasia and calcification in atherosclerotic vessels of LDLr mutant mice

BackgroundVascular calcification is highly prevalent in patients with type II diabetes mellitus (T2DM). Little is known about whether T2DM is causative.MethodsLow-density lipoprotein receptor mutant (LDLr^?/?) mice were fed with customized diabetogenic and/or procalcific diets to induce atherosclerosis, cartilaginous metaplasia and calcification, along with obesity, hyperglycemia, hyperinsulinemia, and hypercholesterolemia at various levels, and euthanized for study after 18–24 weeks on diet.ResultsWe found that T2DM accelerated cartilaginous and calcific lesion development by ~ 3- and 13-fold as determined by incidence of vascular cartilaginous metaplasia and calcification in LDLr^?/? mice. Lowering dietary fat from ~ 60% to ~ 40% kcal reduced body weight and serum glucose and insulin levels, leading to a 2-fold decrease in aortic calcium content. Correlation analysis of calcium content with a calculated insulin resistance index, homeostasis model assessment of insulin resistance, showed a positive correlation of insulin resistance with vascular calcification. Finally, we used genetic fate mapping strategy to trace cells of SM origin in these animals. Vascular smooth muscle cells (SMCs) were found to be a major cell source contributing to osteochondrogenic differentiation and calcification. Receptor for advanced glycation end-products (RAGE) was up-regulated, co-localizing with osteochondrogenic SMCs.ConclusionsThrough quantitative measure of aortic calcium content, we provided experimental findings that LDLr^?/? mice, like T2DM patients, are predisposed to vascular calcification. Our study is also the first to establish a distinct role of hyperglycemia and hypercholesterolemia in osteochondrogenic differentiation of SMCs and determined these cells as a major source contributing to cartilaginous and calcifying lesions of T2DM blood vessels, possibly mediated by RAGE.     

Inducible expression of vascular cell adhesion molecule-1 by vascular smooth muscle cells in vitro and within rabbit atheroma.

Vascular cell adhesion molecule-1 (VCAM-1), a mononuclear leukocyte adhesion molecule, is expressed in cultured vascular endothelial cells activated by cytokines and is induced in rabbit aortic endothelium in vivo within 1 week after initiation of an atherogenic diet. We now demonstrate that vascular smooth muscle cells can also express VCAM-1 in rabbit atherosclerotic lesions in vivo and in response to cytokines in vitro. Immunohistochemical staining of aortas from rabbits fed a 0.3% cholesterol-containing diet revealed that a portion of smooth muscle cells within intimal foam cell-rich lesions expressed VCAM-1. The intimal VCAM-1-expressing cells localized predominantly in regions above the internal elastic lamina. These VCAM-1-positive cells had the typical spindle shape of smooth muscle cells but had reduced alpha-actin expression in comparison to normal medial smooth muscle cells, and did not bear markers for endothelium, macrophages, and T cells. In culture, rabbit aortic smooth muscle cells expressed VCAM-1 mRNA and protein in a time- and concentration-dependent fashion when exposed to interferon-gamma or Gram-negative bacterial lipopolysaccharide. Cultured human vascular smooth muscle cells also expressed VCAM-1 mRNA and protein in response to lipopolysaccharide, interferon-gamma, and interleukin-4. The monokines interleukin-1 alpha and tumor necrosis factor-alpha did not induce VCAM-1 expression in either rabbit or human vascular smooth muscle cells. Inducible VCAM-1 expression by vascular smooth muscle cells in vivo during hypercholesterolemia and in vitro in response to certain cytokines suggests a broader range of VCAM-1 functions in vascular biology than heretofore appreciated.     

Effects of angiotensin II and vasopressin on human smooth muscle cells in vitro

Arterial smooth muscle cell hyperplasia is a histopathological marker of both hypertension and the initial stages of atherogenesis. In order to determine if vasoactive agents could promote arterial smooth muscle cell proliferation, two potent pressor hormones, angiotensin II and vasopressin, were tested in cell culture. Either one of these agents was added daily to cultures of human aortic smooth muscle cells maintained in homologous serum (HS) or fetal bovine serum (FBS). After 7 days, angiotensin II significantly enhanced cell proliferation in both types of sera. While vasopressin was found to be inhibitory in FBS, it also stimulated cell growth in HS. Furthermore, both peptides in HS induced an increase in average cell size. Comparative studies were conducted with human uterine smooth muscle cells and 3T3 mouse fibroblasts in order to determine the specificity of the growth effects for human vascular smooth muscle. The above in vitro studies suggest that angiotensin II and vasopressin, by modulating both number and size of arterial smooth muscle cells, may play a direct and until now unexpected role in the development of chronic vascular disease in man.     

实验性糖尿病大鼠肺组织AGEs、TGF-β1、CTGF免疫组织化学分析

目的 探讨实验性糖尿病(DM)大鼠肺组织晚期糖基化终末产物(AGEs)、转化生长因子-β1(TGF-β1)、结缔组织生长因子(CTGF)的变化及其相关性. 方法 48只SD雄件大鼠随机分为DM组和对照组,每组24只.链脲佐菌素(STZ)60mg/kg尾静脉注射制造DM模型.分别于造模成功后4、12、20周末取材.免疫组织化学方法 观察肺组织AGEs、CTGF、TGF-β1的变化,并进行图像分析. 结果 DM大鼠肺泡上皮细胞、支气管黏膜上皮细胞、血管内皮细胞及平滑肌细胞可见大量AGEs阳性表达,平均灰度值低于对照组(P<0.05).随着DM病程的发展,AGEs阳性表达逐渐降低(P<0.01);4周DM大鼠支气管黏膜上皮细胞、血管内皮细胞、肺问质细胞可见少量CTGF、TGF-β1阳性细胞,12、20用时可见大量CTGF、TGF-β1阳性细胞,平均灰度值均低于对照组(P<0.01);Pearson相关分析显示,DM大鼠肺组织AGEs与CTGF、TGF-β1之间呈显著止相关(γ=0.939、0.904;P<0.01),CTGF与TGF-β1亦呈正相关(y=0.878;P<0.01). 结论 DM大鼠肺组织内AGEs随病程的延长其表达明显增加,并与CTGF、TGF-β1正相关.     

阿卡波糖对糖尿病大鼠主动脉胶原蛋白糖基化的影响

目的:观察新一代α-葡萄糖苷酶抑制剂阿卡波糖(acarbose)对实验性糖尿病(DM)大鼠主动脉胶原非酶糖基化的影响。方法:用链脲佐菌素(50mg·kg^-1,ip)造成大鼠糖尿病模型,分别观察糖尿病组,糖尿病+阿卡波糖组及正常对照组1、3、6个月病程中各组主动脉胶原及胶原非酶糖基化终产物(AGEs)量变化(荧光光谱测定法)。结果:糖尿病大鼠主动脉胶原及胶原AGEs含量明显高于正常对照组,且随病程延长,此种增加更明显(P＜0.01),而阿卡波糖治疗组胶原及胶原AGEs含量降低,与未治疗组相比存在差异(P＜0.01)。结论:阿卡波糖对糖尿病大鼠主动脉胶原蛋白糖基化的形成有抑制作用。     

糖基化终产物和高糖对小牛主动脉血管细胞的损伤作用

目的研究糖基化终产物（AGEs）和高浓度葡萄糖对血管细胞的损伤及对其糖基化终产物受体（RAGE）表达的影响。方法分别用10g/L糖基化终产物、10mol／L葡萄糖和两者的混合作用于牛主动脉血管细胞，利用生化方法测定细胞乳酸脱氢酶（IDH）、还原型谷胱甘肽（GSH）和NO2^-／NO3^-的含量，用MTT法测定细胞的活性。用CELL-ELISA和RT-PCR检测细胞RAGE的表达。结果与正常组（C）相比，高糖组（G）、AGEs组（A）和联合损伤组（G＋A）对主动脉内皮细胞的生长有明显的抑制作用（P〈0．01）和对平滑肌细胞的生长有明显的促进作用，主动脉血管细胞LDH的泄漏量明显增高，GSH和NO2^-／NO3^-的含量明显减少（P〈0．01）；且在的作用最强。同时，联合损伤组血管细胞的RAGE表达水平明显高于AGEs组和高糖组。结论AGEs比高浓度葡萄糖更具损伤血管细胞的作用，且AGEs与高糖联合作用对细胞的损伤最为明显，这种联合损伤的过程也是通过RAGE介导的。联合损伤组     

Swim exercise training ameliorates hepatocyte ultrastructural alterations in rats fed on a high fat and sugar diet

Excessive consumption of carbohydrate and fat increases the risk of liver disease. We hypothesized that swim exercise can protect hepatocytes from ultra-structural damage induced by high cholesterol and fructose diets (HCFD). Rats were either fed with HCFD (model group) or a standard laboratory chow (control group) for 15 weeks before being sacrificed. Swim exercise trained rats started the treatment from the 11^th week until the sacrifice day, end of week 15. Blood samples were assayed for biomarkers of liver injury and adiponectin. The harvested liver tissues were examined using transmission electron microscopy (TEM). TEM images revealed substantial damage and accumulation of lipid droplets (steatosis) in the hepatocytes of the model group that was inhibited by swim exercise. In addition, HCFD significantly (p < 0.0005) increased insulin resistance index (HOMA-IR), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), alanine aminotransferase (ALT), and aspartate aminotransferase (AST), which were effectively (p < 0.02) decreased by a swim exercise to levels comparable to control group. Whereas, swim exercise increased adiponectin levels in HCFD group (p < 0.03). These results show that HCFD-induced hepatic injury is ameliorated by swim training exercise possibly via restoration of a normal blood sugar and lipid, induction of adiponectin and inhibition of inflammatory, and liver injury biomarkers.     

Vasoconstrictor prostanoids

In cardiovascular diseases and during aging, endothelial dysfunction is due in part to the release of endothelium-derived contracting factors that counteract the vasodilator effect of the nitric oxide. Endothelium-dependent contractions involve the activation of endothelial cyclooxygenases and the release of various prostanoids, which activate thromboxane prostanoid (TP) receptors of the underlying vascular smooth muscle. The stimulation of TP receptors elicits not only the contraction and the proliferation of vascular smooth muscle cells but also diverse physiological/pathophysiological reactions, including platelet aggregation and activation of endothelial inflammatory responses. TP receptor antagonists curtail endothelial dysfunction in diseases such as hypertension and diabetes, are potent antithrombotic agents, and prevent vascular inflammation.