Improvement of age-related endothelial dysfunction by simvastatin: effect on NO and COX pathways

The effects of oral administration of the HMG-CoA reductase inhibitor, simvastatin (SV), on age-related endothelial dysfunction were investigated in the aorta of male Wistar rats. Adult (12-14 weeks) and old (60-80 weeks) rats were treated daily for 12 weeks with either vehicle or SV (1 mg kg(-1)). In old rats, SV treatment did not significantly affect systolic blood pressure and LDL-cholesterol, but it reduced plasma cholesterol, triglycerides and oxidised LDL though it did not affect total antioxidant status. SV improved endothelium-dependent relaxation to acetylcholine and A-23187 in vessels from aged, but not adult, rats. This effect was linked to a greater NO vasodilatation via an increased expression of endothelial NO-synthase. A mechanism sensitive to superoxide dismutase and catalase also accounts for enhanced endothelial vasodilatation. Finally, SV did not affect the release of prostacyclin, but it inhibited the generation of thromboxane (TX) A2 from COX-2 isoform. The effect of the latter was sensitive to the Tp receptor antagonist, ICI-192,605. The present study provides evidence that oral administration of SV improves endothelial dysfunction in the aorta from aged rats by mechanisms associated with enhanced NO vasodilatation, reduced release of TXA2 from cyclo-oxygenase, and increased antioxidant properties of the vessel wall. These data underscore a new therapeutic perspective for SV in age-related endothelial dysfunction.     

Investigation of vascular endothelial dysfunction in the patients with age-related macular degeneration

Purpose: This study aims to evaluate the association between age-related macular degeneration (AMD) and cardiovascular disease by using the noninvasive flow-mediated dilation (FMD) test to show endothelial dysfunction as an indicator of subclinical atherosclerosis.

Method: Participants in this study included 30?dry AMD patients, 30 wet AMD patients, and 30 healthy controls without any systemic disease, including AMD. FMD and the intima media thickness (IMT) of the carotid artery were compared between the groups.

Results: Comparison of FMD between the groups showed a 10.96% brachial artery dilation in the healthy controls, 3.99% in the dry AMD group, and 5.03% in the wet AMD group. While a significant difference was not observed between the wet and dry AMD groups, comparison of the control group to the wet and dry AMD groups yielded a significant difference. When brachial artery dilation below 7% was accepted as an abnormal FMD, 26.7% of the healthy controls, 66.7% of the dry AMD patients and 76.7% of the wet AMD patients were found to be abnormal. Similarly, while no significant difference was observed between the wet and dry AMD groups, comparison of the control group with the wet and dry AMD patients yielded a significant difference. When an IMT below 0.7?mm was accepted as abnormal, 26.7% of the healthy controls, 33.3% of the dry AMD, and 43.3% of the wet AMD were found to have an abnormal IMT. However, differences between the groups did not reach statistical significance.

Conclusions: In this study, use of the FMD test showed endothelial dysfunction among AMD patients. No significant differences were found between the dry and wet AMD patient groups.     

Vascular eicosanoids and platelet-aortic wall interactions in spontaneously hypertensive rats.

We studied the aggregation of collagen and ADP-stimulated platelet-rich plasma (PRP) and the formation of thromboxane B2 (TxB2) by collagen-stimulated PRP in spontaneously hypertensive rats (SHR) and in Wistar-Kyoto control rats (WKY). In addition, we evaluated the inhibition of the aggregation of PRP following homologous or heterologous perfusions through isolated aortas, the release of 6-keto-prostaglandin (PG)F1 alpha from these arteries perfused with PRP, and the sensitivity of PRP to the antiaggregatory activity of the stable PGI2 analogue, iloprost, in both SHR and WKY. The lower activities (aggregation induced by ADP and collagen, collagen-stimulated TxB2 production) of SHR platelets, were not accompanied by morphological differences from WKY platelets. These changes were associated with a greater release of arterial 6-keto-PGF1 alpha, with greater platelet antiaggregatory activity of the arterial wall and with higher sensitivity of platelets to iloprost. The lower reactivity of platelets to aggregating agents, and the greater sensitivity to prostacyclin, associated with a greater production of arterial prostacyclin were the major changes observed in SHR animals. These alterations in the SHR vs. normotensive WKY may lead to an enhanced risk of hemorrhage in the hypertensive state.     

Vascular NO: from bench to bedside

European Journal of Clinical Pharmacology -     

Apigenin and naringenin ameliorate PKCβII-associated endothelial dysfunction via regulating ROS/caspase-3 and NO pathway in endothelial cells exposed to high glucose

Endothelial dysfunction is a key event in the progression of atherosclerosis with diabetes. Increasing cell apoptosis may lead to endothelial dysfunction. Apigenin and naringenin are two kinds of widely used flavones. In the present study, we investigated whether and how apigenin and naringenin reduced endothelial dysfunction induced by high glucose in endothelial cells. We showed that apigenin and naringenin protected against endothelial dysfunction via inhibiting phosphorylation of protein kinase C βII (PKCβII) expression and downstream reactive oxygen species (ROS) production in endothelial cells exposed to high glucose. Furthermore, we demonstrated that apigenin and naringenin reduced high glucose-increased apoptosis, Bax expression, caspase-3 activity and phosphorylation of NF-κB in endothelial cells. Moreover, apigenin and naringenin effectively restored high glucose-reduced Bcl-2 expression and Akt phosphorylation. Importantly, apigenin and naringenin significantly increased NO production in endothelial cells subjected to high glucose challenge. Consistently, high glucose stimulation impaired acetylcholine (ACh)-mediated vasodilation in the rat aorta, apigenin and naringenin treatment restored the impaired endothelium-dependent vasodilation via dramatically increasing eNOS activity and nitric oxide (NO) level. Taken together, our results manifest that apigenin and naringenin can ameliorate endothelial dysfunction via regulating ROS/caspase-3 and NO pathway.     

Vascular dysfunction in the alpha-galactosidase A-knockout mouse is an endothelial cell-, plasma membrane-based defect

Fabry disease results from an X-linked mutation in the lysosomal alpha-galactosidase A (Gla) gene. Defective Gla results in multi-organ accumulation of neutral glycosphingolipids (GSLs), especially in the vascular endothelium, with the major GSL accumulated being globotriaosylceramide (Gb3). Excessive endothelial Gb3 accumulation is associated with increased thrombosis, atherogenesis and endothelial dysfunction. However, the mechanism(s) by which endothelial dysfunction occurs is unclear. The purpose of the present study was to further characterize the vasculopathy associated with a murine model of Fabry disease. Vascular reactivity was performed in vessels from wild-type (Gla(+/0)) and Gla-knockout (Gla(-/0)) mice. Conscious blood pressure and heart rate were measured in Gla(+/0) and Gla(-/0) mice by telemetry. The present study demonstrates that vascular smooth muscle (VSM) contractions to phenylephrine and serotonin, but not to U46619, were blunted in Gla(-/0) mice. Endothelium-dependent contraction and receptor-mediated endothelium-dependent relaxation to acetylcholine were significantly attenuated in vessels from Gla(-/0) mice. However, receptor-independent endothelium-dependent relaxation to the calcium ionophore ionomycin remained intact in vessels from Gla(-/0) mice. Furthermore, VSM reactivity was normal in aortas from Gla(-/0) mice in the absence of endothelium. These changes in vascular function were observed without changes in whole-animal blood pressure or heart rate. These results suggest that the vasculopathy associated with Fabry disease is localized to the endothelium, despite the accumulation of GSLs throughout the vasculature.     

高尿酸血症患者的血管内皮功能研究

目的探讨高尿酸血症患者的血管内皮功能状况。方法控制影响血管内皮功能的因素后纳入观察组中78例高尿酸血症患者,以及年龄、性别匹配的对照组75名,采用超声检测血管内皮功能进行比较。结果观察组血流介导的血管舒张（FNV）较对照组明显下降（P〈0．05）,两组在年龄、性别、体质量、血压、血脂、血糖水平差异无统计学意义（P〉0．05）。结论高尿酸血症患者存在血管内皮功能障碍,是动脉粥样硬化的危险因素。     

Effects of eicosanoids and nitric oxide on the noradrenaline-induced contractions in the rat mesenteric bed

1. The effects of the inhibition of the metabolism of arachidonic acid (AA) on the constrictor responses to noradrenaline (NA) were studied in the rat perfused mesenteric bed. The inhibitor of all the pathways of AA metabolism, 10 microM eicosatetraynoic acid (ETYA), reduced the constrictor responses to all the concentrations of NA assayed. 2. The constrictor responses to NA were also reduced by the cyclooxygenase (COX) inhibitor, indomethacin (10 microM), as well as by the lipoxygenase inhibitor, nordihidroguaiaretic acid (1 microM; NDGA), whereas they were unmodified by the cytochrome P450 monooxigenase inhibitors, clotrimazole (10 microM), metyrapone (10 microM) and proadifen (10 microM). 3. The reduction in NA contractility induced by indomethacin was reverted with a decreasing order of potency by the thromboxane A2 analogue, U-46619 > prostaglandin (PG) E2 > PGF2alpha. The exposure of the mesenteric bed to NA increased the production of PGF2alpha, whereas it did not modify the production of the remaining AA metabolites. 4. The increase in the NA-induced contractions caused by endothelium removal, as well as by the inhibition of nitric oxide synthase (NOs) with NG-nitro-L-arginine methyl ester (400 microM; L-NAME), was suppressed by indomethacin but not by NDGA. These observations suggest that the lipoxygenase-derived metabolites are formed in the endothelium, whereas the COX-derived metabolites are formed in the vascular smooth muscle. 5. The TP receptor antagonist, SQ29548, did not modify the NA-induced contractions, either in the presence or in the absence of the endothelium. 6. Contractions elicited by KCI (60-100 mM) were unmodified by the AA metabolism inhibitors, ETYA, NDGA and indomethacin. 7. In summary, these results show that metabolites of AA, through both the COX and the lipoxygenase pathways, are involved in the NA-induced contractions in the rat mesenteric bed. The lipoxygenase metabolites are likely to be formed in the vascular endothelium, whereas the COX metabolite, which could be PGF2alpha, is apparently formed within the vascular smooth muscle.     

Vascular endothelial growth factor-C in patients with breast cancer

Metastatic spread of tumours is the major cause of death in patients with breast cancer. Despite the importance of the lymphatic system in tumour metastasis, little is known about the role of lymphangiogenesis in tumour growth and metastasis. This study was undertaken to evaluate the potential usefulness of plasma levels of lymphanagiogenesis factor, vascular endothelial cell growth factor-C (VEGF-C) as a prognostic factor in 122 patients with breast cancer. There was no significant difference between plasma levels of VEGF-C in patients with early (n =81), advanced (n =32) or inflammatory breast cancer (n =9) and 64 age matched healthy controls. We found no significant correlation between VEGF-C with age, tumour size, tumour grade, or disease-free and over-all survival. Plasma VEGF-C levels did not significantly differ in patients with positive oestrogen, progesterone, and Her-2 neu compared to those who were negative for these parameters. In conclusion our study has failed to show any prognostic value for plasma VEGF-C level in patients with breast cancer.     

慢性心房颤动患者P-选择素水平及内皮功能障碍

目的研究慢性心房颤动 (房颤 )患者血小板活化和内皮功能障碍的有关标志物 ,探讨其临床意义。方法采用酶联免疫双抗体夹心法测定心脏病患者房颤组 (30例 )、无房颤组 (2 0例 )和正常对照组 (1 7例 )的血浆P 选择素 (P selectin)及血管性血友病因子 (vonWillebrandfactorvWF)的水平。结果房颤组血浆P 选择素及vWF水平显著高于无房颤组及正常对照组 (P均 <0 0 1 ) ,无房颤组与正常对照组比较上述指标亦增高 (P <0 0 1 )。结论慢性房颤组患者存在血小板激活和内皮功能障碍 ,这些异常可能参与了房颤患者血栓的形成     

Inflammatory response and endothelial dysfunction in the hearts of mice co‐exposed to SO2, NO2, and PM2.5

SO₂, NO₂, and PM_2.5 are typical air pollutants produced during the combustion of coal. Increasing evidence indicates that air pollution has contributed to the development and progression of heart‐related diseases over the past decades. However, little experimental data and few studies of SO₂, NO₂, and PM_2.5 co‐exposure in animals exist; therefore, the relevant mechanisms underlying this phenomenon are unclear. An important characteristic of air pollution is that co‐exposure persists at a low concentration throughout a lifetime. In the present study, we treated adult mice with SO₂, NO₂, and PM_2.5 at various concentrations (0.5 mg/m³ SO₂, 0.2 mg/m³ NO₂ 6 h/d, with intranasal instillation of 1 mg/kg PM_2.5 every other day during these exposures; or 3.5 mg/m³ SO₂, 2 mg/m³ NO₂ 6 h/d, and 10 mg/kg PM_2.5 for 28 d). Blood pressure (BP), heart rate (HR), histopathological damage, and inflammatory and endothelial cytokines in the heart were assessed. The results indicate that co‐exposure caused endothelial dysfunction by elevating endothelin‐1 (ET‐1) expression and repressing the endothelial nitric oxide synthase (eNOS) level as well as stimulating the inflammatory response by increasing the levels of cyclooxygenase‐2 (COX‐2), inducible nitric oxide synthase (iNOS), tumor necrosis factor‐α (TNF‐α) and interleukin‐6 (IL‐6). Additionally, these alterations were confirmed by histological staining. Furthermore, we observed decreased BP and increased HR after co‐exposure. Our results indicate that co‐exposure to SO₂, NO₂, and PM_2.5 may be a major risk factor for cardiac disease and may induce injury to the hearts of mammals and contribute to heart disease. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1996–2005, 2016.     

Vascular endothelial growth factor and angiogenesis

Angiogenesis is a hallmark of wound healing, the menstrual cycle, cancer, and various ischemic and inflammatory diseases. A rich variety of pro- and antiangiogenic molecules have already been discovered. Vascular endothelial growth factor (VEGF) is an interesting inducer of angiogenesis and lymphangiogenesis, because it is a highly specific mitogen for endothelial cells. Signal transduction involves binding to tyrosine kinase receptors and results in endothelial cell proliferation, migration, and new vessel formation. In this article, the role of VEGF in physiological and pathological processes is reviewed. We also discuss how modulation of VEGF expression creates new therapeutic possibilities and describe recent developments in this field.     

Cyclo-oxygenase-1 and -2 contribution to endothelial dysfunction in ageing

Experiments were designed to investigate the role of cyclo-oxygenase isoforms in endothelial dysfunction in ageing. Aortic rings with endothelium of aged and young (24 vs 4 month-old) Wistar rats, were mounted in organ chambers for the recording of changes in isometric tension. In young rats, acetylcholine (ACh) caused a complete relaxation which was not affected by indomethacin (0.3 microM), NS-398 (a preferential COX-2 inhibitor; 1 microM), SQ-29548 (a thromboxane-receptor antagonist; 1 microM), nor valeryl-salicylate (VAS, a preferential inhibitor of COX-1; 3 mM). In aged rats, ACh caused a biphasic response characterized by a first phase of relaxation (0.01 - 1 microM ACh), followed by a contraction (3 - 100 microM ACh). Indomethacin, NS-398 and SQ-29548, but not VAS, augmented the first phase. Indomethacin, VAS, NS-398 and SQ-29548 decreased the contractions to high ACh concentrations. Then, the sensitivity to thromboxane receptor activation was investigated with U-46619. The results show comparable EC(50) values in young and aged rats. In aged rats, the ACh-stimulated release of prostacyclin, prostaglandin F(2alpha) and thromboxane A(2) was decreased by either indomethacin, NS-398, VAS or endothelium removal. However, in young animals, the ACh-stimulated release of prostacyclin and prostaglandin F(2alpha) were smaller than in older animals and remained unaffected by NS-398. Aortic endothelial cells from aged - but not young - rats express COX-2 isoform, while COX-1 labelling was observed in endothelial cells from both young and aged rats. These data demonstrate the active contribution of COX-1 and -2 in endothelial dysfunction associated with ageing.     

心肌梗死患者血管内皮功能的超声检测

目的 :研究心肌梗死患者的血管内皮功能。方法 :心肌梗死 (MI)患者 10例 ,以血管多普勒超声测定外周肱动脉血管内皮依赖性舒张功能 (EDD)和内皮非依赖性舒张功能 (NEDD)。结果 :MI患者血管内皮功能包括EDD和NEDD均较正常对照明显障碍。结论 :心肌梗死患者的血管内皮功能明显障碍     

Implicating endothelial cell senescence to dysfunction in the ageing and diseased brain

Cerebrovascular endothelial cells (CECs) are integral components of both the blood‐brain barrier (BBB) and the neurovascular unit (NVU). As the primary cell type of the BBB, CECs are responsible for the tight regulation of molecular transport between the brain parenchyma and the periphery. Additionally, CECs are essential in neurovascular coupling where they help regulate cerebral blood flow in response to regional increases in cellular demand in the NVU. CEC dysfunction occurs during both normative ageing and in cerebrovascular disease, which leads to increased BBB permeability and neurovascular uncoupling. This MiniReview compiles what is known about the molecular changes underlying CEC dysfunction, many of which are reminiscent of cells that have become senescent. In general, cellular senescence is defined as an irreversible growth arrest characterized by the acquisition of a pro‐inflammatory secretory phenotype in response to DNA damage or other cellular stresses. We discuss evidence for endothelial cell senescence in ageing and cardiovascular disease, and how CEC senescence may contribute to age‐related cerebrovascular dysfunction.     

Plasma biomarkers of endothelial dysfunction in patients with hypertrophic cardiomyopathy

Impairment of endothelium-dependent coronary vasodilatation has been reported in hypertrophic cardiomyopathy (HCM). The aim of our study was to evaluate whether HCM patients have increased circulating blood markers of endothelial dysfunction. We compared 29 HCM patients with sinus rhythm, including 11 with the left ventricular outflow tract (LVOT) obstruction (gradient > 30 mmHg), versus 29 age- and sex-matched controls without cardiovascular diseases. Plasma levels of the following endothelial biomarkers were determined: soluble thrombomodulin (sTM), von Willebrand factor (vWF), tissue factor pathway inhibitor (TFPI), asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDAM) and L-arginine to ADMA (Arg/ADMA) ratio. Both sTM (49.1 +/- 9.9 vs. 39.1 +/- 4.8 ng/ml, p < 0.00001) and TFPI (18.6 +/- 2.5 vs. 16.2 +/- 1.7 ng/ml, p < 0.0001) were elevated in HCM patients compared with controls, whereas vWF levels were similar in both groups (105.8 +/- 11.6 vs. 102.2 +/- 10.9 U/dl, p > 0.05). Among markers related to the nitric oxide pathways, we observed elevations of both ADMA (0.57 +/- 0.08 vs. 0.44 +/- 0.04 mumol/l, p < 0.0001) and SDMA(0.43 +/- 0.05 vs. 0.34 +/- 0.04 mumol/l, p < 0.0001) and decrease in the Arg/ADMA ratio (118.1 +/- 18.2 vs. 144.3 +/- 22.1, p < 0.0001) in HCM patients. The obstructive HCM subgroup displayed higher values of ADMA, SDMAand sTM compared with the non-obstructive HCM subgroup. HCM patients show specific features of endothelial dysfunction detectable in peripheral blood, involving increased sTM and TFPI, but not vWF, along with increased ADMA levels.