scholarly journals Decreased endothelial nitric oxide, systemic oxidative stress, and increased sympathetic modulation contribute to hypertension in obese rats

2014 ◽  
Vol 306 (10) ◽  
pp. H1472-H1480 ◽  
Author(s):  
Natalia Veronez da Cunha ◽  
Phileno Pinge-Filho ◽  
Carolina Panis ◽  
Bruno Rodrigues Silva ◽  
Laena Pernomian ◽  
...  

We investigated the involvement of nitric oxide (NO) and reactive oxygen species (ROS) on autonomic cardiovascular parameters, vascular reactivity, and endothelial cells isolated from aorta of monosodium glutamate (MSG) obese rats. Obesity was induced by administration of 4 mg/g body wt of MSG or equimolar saline [control (CTR)] to newborn rats. At the 60th day, the treatment was started with NG-nitro-l-arginine methyl ester (l-NAME, 20 mg/kg) or 0.9% saline. At the 90th day, after artery catheterization, mean arterial pressure (MAP) and heart rate were recorded. Plasma was collected to assess lipid peroxidation. Endothelial cells isolated from aorta were evaluated by flow cytometry and fluorescence intensity (FI) emitted by NO-sensitive dye [4,5-diaminofluoresceindiacetate (DAF-2DA)] and by ROS-sensitive dye [dihydroethidium (DHE)]. Vascular reactivity was made by concentration-response curves of acetylcholine. MSG showed hypertension compared with CTR. Treatment with l-NAME increased MAP only in CTR. The MSG induced an increase in the low-frequency (LF) band and a decrease in the high-frequency band of pulse interval. l-NAME treatment increased the LF band of systolic arterial pressure only in CTR without changes in MSG. Lipid peroxidation levels were higher in MSG and were attenuated after l-NAME. In endothelial cells, basal FI to DAF was higher in CTR than in MSG. In both groups, acetylcholine increased FI for DAF from basal. The FI baseline to DHE was higher in MSG than in CTR. Acetylcholine increased FI to DHE in the CTR group, but decreased in MSG animals. We suggest that reduced NO production and increased production of ROS may contribute to hypertension in obese MSG animals.

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Emily E Morin ◽  
Yanhong Guo ◽  
Rui Kuai ◽  
Gergely Lautner ◽  
Mark E Meyerhoff ◽  
...  

Introduction: Sphingosine-1-phosphate (S1P) is a potent anti-inflammatory signaling lipid carried in the body by circulating HDL. HDL has been shown to exhibit anti-inflammatory activities through activation of endothelial nitric oxide synthase (eNOS) and subsequent production and release of nitric oxide (NO) by endothelial cells. Objective: The aim of this study is to use synthetic HDL particles to selectively deliver S1P to the site of arterial plaques in order to exert anti-inflammatory activity and modulate the progression of atherosclerosis. Methods/Results: Synthetic HDL (sHDL) particles were prepared using the ApoA1 mimetic peptide 22A (PVLDLFRELLNELLEALKQKLK), dipalmitoylphosphatidylcholine (DPPC) and sphingomyelin. We also prepared sHDL containing either the hydrophobic dye, DiD, or S1P to assess the capability of sHDL to effectively reach atheroma site and induce nitric oxide (NO) release, respectively. The purity of all particles was determined to be > 97% and average particle size was 9.6 ± 0.4 nm for all preparations. To measure sHDL accumulation in the plaque, ApoE -/- mice were intravenously injected with 0.2 mg/kg HDL-DiD. Whole aortas were excised and analysed by IVUS imaging system, revealing significant accumulation of sHDL-DiD in the atherosclerotic lesions. We then tested the ability of sHDL to deliver S1P in vitro and induce NO production by treating human umbilical vein endothelial cells (HUVEC) with 1 mg/mL of 22A-DPPC-sHDL containing 0, 0.05, 0.5, or 5 nmol/mL of S1P using free 22A peptide (1 mg/mL) and saline as controls, and analyzing media by ozone chemiluminescence. Blank sHDL particles increased NO production two-fold over controls (0.27 ± 0.02 μM for 22A-DPPC-sHDLDL, 0.13 ± 0.01 μM PBS and 0.14 ± 0.02 μM for 22A peptide), while HDL-S1P further increased NO release: 0.35 ± 0.03, 0.44 ± 0.01, and 0.59 ± 0.01 μM for HDL with 0.05, 0.5, and 5 nmol/mL S1P, respectively. Conclusions: Our studies show that HDL is capable of delivering hydrophobic cargo to atherosclerotic plaques, making HDL a promising platform to deliver S1P for modulation vascular inflammation and atherosclerosis. In vitro studies have revealed that HDL-S1P is able to increase NO production 2 to 4-fold over saline control setting the basis for future in vivo studies.


2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Aline de Freitas Brito ◽  
Alexandre Sérgio Silva ◽  
Alesandra Araújo de Souza ◽  
Paula Benvindo Ferreira ◽  
Iara Leão Luna de Souza ◽  
...  

The possible mechanism is involved in the effects of Spirulina platensis on vascular reactivity. Animals were divided into sedentary group (SG) and sedentary groups supplemented with S. platensis at doses of 50 (SG50), 150 (SG150), and 500 mg/kg (SG500). To evaluate reactivity, cumulative concentration-response curves were constructed for phenylephrine and acetylcholine. To evaluate the involvement of the nitric oxide (NO) pathway, aorta tissue was preincubated with L-NAME and a new curve was then obtained for phenylephrine. Biochemical analyses were performed to evaluate nitrite levels, lipid peroxidation, and antioxidant activity. To contractile reactivity, only SG500 (pD2=5.6±0.04 vs. 6.1±0.06, 6.2±0.02, and 6.2±0.04) showed reduction in phenylephrine contractile potency. L-NAME caused a higher contractile response to phenylephrine in SG150 and SG500. To relaxation, curves for SG150 (pD2=7.0±0.08 vs. 6.4±0.06) and SG500 (pD2=7.3±0.02 vs. 6.4±0.06) were shifted to the left, more so in SG500. Nitrite was increased in SG150 and SG500. Lipid peroxidation was reduced, and oxidation inhibition was increased in all supplemented groups, indicating enhanced antioxidant activity. Chronic supplementation with S. platensis (150/500 mg/kg) caused a decrease in contractile response and increase in relaxation and nitrite levels, indicating greater NO production, due to decreased oxidative stress and increased antioxidant activity.


1993 ◽  
Vol 13 (2) ◽  
pp. 61-67 ◽  
Author(s):  
R. J. Bing ◽  
A. Termin ◽  
A. Conforto ◽  
R. Dudek ◽  
M. J. Hoffmann

This communication examines the possibility that nitric oxide (NO) production by endothelial cells results from changes in cell membrane fluidity. Lysophosphatidylcholine (LPC) alters fluidity of the endothelial cell membranes causing vascular relaxation. Through membrane alterations LPC influences function of a number of membrane receptors and modulates enzyme activity. As a result of detergent action, lysophosphatidylcholine (LPC) causes activation of guanylate cyclase, stimulates syalytransferase and regulates protein kinase C activity. It has already been demonstrated that ionic detergents, such as Triton X-100 also cause vascular relaxation, possibly induced by NO production from endothelial cells. It is postulated that production of nitric oxide results from changes in membrane viscosity; this may represent a mechanism for its regulation in biological systems.


2007 ◽  
Vol 293 (2) ◽  
pp. R707-R713 ◽  
Author(s):  
Sharyn M. Fitzgerald ◽  
Barbara K. Kemp-Harper ◽  
Helena C. Parkington ◽  
Geoffrey A. Head ◽  
Roger G. Evans

We determined whether nitric oxide (NO) counters the development of hypertension at the onset of diabetes in mice, whether this is dependent on endothelial NO synthase (eNOS), and whether non-NO endothelium-dependent vasodilator mechanisms are altered in diabetes in mice. Male mice were instrumented for chronic measurement of mean arterial pressure (MAP). In wild-type mice, MAP was greater after 5 wk of Nω-nitro-l-arginine methyl ester (l-NAME; 100 mg·kg−1·day−1 in drinking water; 97 ± 3 mmHg) than after vehicle treatment (88 ± 3 mmHg). MAP was also elevated in eNOS null mice (113 ± 4 mmHg). Seven days after streptozotocin treatment (200 mg/kg iv) MAP was further increased in l-NAME-treated mice (108 ± 5 mmHg) but not in vehicle-treated mice (88 ± 3 mmHg) nor eNOS null mice (104 ± 3 mmHg). In wild-type mice, maximal vasorelaxation of mesenteric arteries to acetylcholine was not altered by chronic l-NAME or induction of diabetes but was reduced by 42 ± 6% in l-NAME-treated diabetic mice. Furthermore, the relative roles of NO and endothelium-derived hyperpolarizing factor (EDHF) in acetylcholine-induced vasorelaxation were altered; the EDHF component was enhanced by l-NAME and blunted by diabetes. These data suggest that NO protects against the development of hypertension during early-stage diabetes in mice, even in the absence of eNOS. Furthermore, in mesenteric arteries, diabetes is associated with reduced EDHF function, with an apparent compensatory increase in NO function. Thus, prior inhibition of NOS results in endothelial dysfunction in early diabetes, since the diabetes-induced reduction in EDHF function cannot be compensated by increases in NO production.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Ping-Ho Chen ◽  
Yaw-Syan Fu ◽  
Yun-Ming Wang ◽  
Kun-Han Yang ◽  
Danny Ling Wang ◽  
...  

Hydrogen sulfide (H2S) and nitric oxide (NO), two endogenous gaseous molecules in endothelial cells, got increased attention with respect to their protective roles in the cardiovascular system. However, the details of the signaling pathways between H2S and NO in endothelia cells remain unclear. In this study, a treatment with NaHS profoundly increased the expression and the activity of endothelial nitric oxide synthase. Elevated gaseous NO levels were observed by a novel and specific fluorescent probe, 5-amino-2-(6-hydroxy-3-oxo-3H-xanthen-9-yl)benzoic acid methyl ester (FA-OMe), and quantified by flow cytometry. Further study indicated an increase of upstream regulator for eNOS activation, AMP-activated protein kinase (AMPK), and protein kinase B (Akt). By using a biotin switch, the level of NO-mediated protein S-nitrosylation was also enhanced. However, with the addition of the NO donor, NOC-18, the expressions of cystathionine-γ-lyase, cystathionine-β-synthase, and 3-mercaptopyruvate sulfurtransferase were not changed. The level of H2S was also monitored by a new designed fluorescent probe, 4-nitro-7-thiocyanatobenz-2-oxa-1,3-diazole (NBD-SCN) with high specificity. Therefore, NO did not reciprocally increase the expression of H2S-generating enzymes and the H2S level. The present study provides an integrated insight of cellular responses to H2S and NO from protein expression to gaseous molecule generation, which indicates the upstream role of H2S in modulating NO production and protein S-nitrosylation.


2004 ◽  
Vol 287 (1) ◽  
pp. L60-L68 ◽  
Author(s):  
Louis G. Chicoine ◽  
Michael L. Paffett ◽  
Tamara L. Young ◽  
Leif D. Nelin

Nitric oxide (NO) is produced by NO synthase (NOS) from l-arginine (l-Arg). Alternatively, l-Arg can be metabolized by arginase to produce l-ornithine and urea. Arginase (AR) exists in two isoforms, ARI and ARII. We hypothesized that inhibiting AR with l-valine (l-Val) would increase NO production in bovine pulmonary arterial endothelial cells (bPAEC). bPAEC were grown to confluence in either regular medium (EGM; control) or EGM with lipopolysaccharide and tumor necrosis factor-α (L/T) added. Treatment of bPAEC with L/T resulted in greater ARI protein expression and ARII mRNA expression than in control bPAEC. Addition of l-Val to the medium led to a concentration-dependent decrease in urea production and a concentration-dependent increase in NO production in both control and L/T-treated bPAEC. In a second set of experiments, control and L/T bPAEC were grown in EGM, EGM with 30 mM l-Val, EGM with 10 mM l-Arg, or EGM with both 10 mM l-Arg and 30 mM l-Val. In both control and L/T bPAEC, treatment with l-Val decreased urea production and increased NO production. Treatment with l-Arg increased both urea and NO production. The addition of the combination l-Arg and l-Val decreased urea production compared with the addition of l-Arg alone and increased NO production compared with l-Val alone. These data suggest that competition for intracellular l-Arg by AR may be involved in the regulation of NOS activity in control bPAEC and in response to L/T treatment.


2000 ◽  
Vol 279 (4) ◽  
pp. F671-F678 ◽  
Author(s):  
Xiaohui Zhang ◽  
Hong Li ◽  
Haoli Jin ◽  
Zachary Ebin ◽  
Sergey Brodsky ◽  
...  

Hyperhomocysteinemia (HHCy) is an independent and graded cardiovascular risk factor. HHCy is prevalent in patients with chronic renal failure, contributing to the increased mortality rate. Controversy exists as to the effects of HHCy on nitric oxide (NO) production: it has been shown that HHCy both increases and suppresses it. We addressed this problem by using amperometric electrochemical NO detection with a porphyrinic microelectrode to study responses of endothelial cells incubated with homocysteine (Hcy) to the stimulation with bradykinin, calcium ionophore, or l-arginine. Twenty-four-hour preincubation with Hcy (10, 20, and 50 μM) resulted in a gradual decline in responsiveness of endothelial cells to the above stimuli. Hcy did not affect the expression of endothelial nitric oxide synthase (eNOS), but it stimulated formation of superoxide anions, as judged by fluorescence of dichlorofluorescein, and peroxynitrite, as detected by using immunoprecipitation and immunoblotting of proteins modified by tyrosine nitration. Hcy did not directly affect the ability of recombinant eNOS to generate NO, but oxidation of sulfhydryl groups in eNOS reduced its NO-generating activity. Addition of 5-methyltetrahydrofolate restored NO responses to all agonists tested but affected neither the expression of the enzyme nor formation of nitrotyrosine-modified proteins. In addition, a scavenger of peroxynitrite or a cell-permeant superoxide dismutase mimetic reversed the Hcy-induced suppression of NO production by endothelial cells. In conclusion, electrochemical detection of NO release from cultured endothelial cells demonstrated that concentrations of Hcy >20 μM produce a significant indirect suppression of eNOS activity without any discernible effects on its expression. Folates, superoxide ions, and peroxynitrite scavengers restore the NO-generating activity to eNOS, collectively suggesting that cellular redox state plays an important role in HCy-suppressed NO-generating function of this enzyme.


2013 ◽  
Vol 304 (7) ◽  
pp. E695-E702 ◽  
Author(s):  
Hong-Bo Ci ◽  
Zhi-Jun Ou ◽  
Feng-Jun Chang ◽  
Dong-Hong Liu ◽  
Guo-Wei He ◽  
...  

Mitral valve endothelial cells are important for maintaining lifelong mitral valve integrity and function. Plasma endothelial microparticles (EMPs) increased in various pathological conditions related to activation of endothelial cells. However, whether EMPs will increase in mitral valve disease and their relationship remains unclear. Here, 81 patients with mitral valve disease and 45 healthy subjects were analyzed for the generation of EMPs by flow cytometry. Human mitral valve endothelial cells (HMVECs) were treated with EMPs. The phosphorylation of Akt and endothelial nitric oxide synthase (eNOS), the association of eNOS and heat shock protein 90 (HSP90), and the generation of nitric oxide (NO) and superoxide anion (O2˙−) were measured. EMPs were increased significantly in patients with mitral valve disease compared with those in healthy subjects. EMPs were negatively correlated with mitral valve area in patients with isolated mitral stenosis. EMPs were significantly higher in the group with severe mitral regurgitation than those in the group with mild and moderate mitral regurgitation. Furthermore, EMPs were decreased dramatically in both Akt and eNOS phosphorylation and the association of HSP90 with eNOS in HMVECs. EMPs decreased NO production but increased O2˙− generation in HMVECs. Our data demonstrated that EMPs were significantly increased in patients with mitral valve disease. The increase of EMPs can in turn impair HMVEC function by inhibiting the Akt/eNOS-HSP90 signaling pathway. These findings suggest that EMPs may be a therapeutic target for mitral valve disease.


2021 ◽  
Vol 22 (19) ◽  
pp. 10287
Author(s):  
Chih-Hsien Wu ◽  
Yi-Lin Chiu ◽  
Chung-Yueh Hsieh ◽  
Guo-Shiang Tsung ◽  
Lian-Shan Wu ◽  
...  

Cilostazol was suggested to be beneficial to retard in-stent atherosclerosis and prevent stent thrombosis. However, the mechanisms responsible for the beneficial effects of cilostazol are not fully understood. In this study, we attempted to verify the mechanism of the antithrombotic effect of cilostazol. Human umbilical vein endothelial cells (HUVECs) were cultured with various concentrations of cilostazol to verify its impact on endothelial cells. KLF2, silent information regulator transcript-1 (SIRT1), endothelial nitric oxide synthase (eNOS), and endothelial thrombomodulin (TM) expression levels were examined. We found cilostazol significantly activated KLF2 expression and KLF2-related endothelial function, including eNOS activation, Nitric oxide (NO) production, and TM secretion. The activation was regulated by SIRT1, which was also stimulated by cilostazol. These findings suggest that cilostazol may be capable of an antithrombotic and vasculoprotective effect in endothelial cells.


Author(s):  
А.А. Московцев ◽  
А.Н. Мыльникова ◽  
Д.В. Колесов ◽  
А.А. Микрюкова ◽  
Д.М. Зайченко ◽  
...  

Эндотелиальные клетки, выстилающие стенки сосудов, преобразовывают деформацию собственных структур, вызванную током крови, в химические сигналы, одним из которых является важный регулятор просвета сосуда - оксид азота (NO). К настоящему моменту накоплен большой объём данных о клеточных механизмах активации продукции NO, однако сведений о динамике генерации оксида азота эндотелиальными клетками в зависимости от гидродинамических условий недостаточно. В этой связи разработка микрофлюидных систем in vitro, имитирующих кровеносное русло, и изучение в них эндотелия в сложных гидродинамических условиях является актуальной задачей. В данной работе для создания контролируемых гидродинамических условий для монослоя эндотелиоцитоподобных клеток EA.hy926 была спроектирована и разработана микрофлюидная система, имитирующая линейные участки микрососудистого русла. Методом непрямого определения содержания оксида азота (II) NO с использованием флуоресцентного зонда 4,5-диаминофлуоресцеина DAF-2 впервые получены данные об увеличении продукции NO клетками EA.hy926 при механическом стрессе, создаваемом потоком ростовой среды. Представлены расчетные гидродинамические характеристики микрофлюидной системы, а также методика измерения продукции NO. Возможность исследования функциональной активности эндотелия позволяет использовать разработанную микрофлюидную модельную систему как для изучения клеточно-автономных регуляторных свойств эндотелия при действии ряда вазоактивных фармакологических препаратов и других методов воздействия на эндотелий, так и при моделируемой дисфункции эндотелия. Endothelial cells lining vascular walls transform the flow-induced deformation of their own structures into chemical signals, one of which, nitric oxide (NO), is an important regulator of the vascular lumen diameter. By present, a large amount of data on cellular mechanisms for activation of NO production has been accumulated. However, there is insufficient information on changes in endothelial NO generation under different hydrodynamic conditions. Therefore, development of microfluidic systems that model blood vessels in vitro and using them to study the endothelium under complex hydrodynamic conditions are relevant tasks. In this study, a microfluidic system was developed to create controlled hydrodynamic conditions for a monolayer of endotheliocyte-like cells EAhy.926. This system simulates linear sections of the microvasculature. By indirect measurement of NO (II) content with a fluorescent 4,5-diaminofluorescein (DAF-2) probe, we showed an increase in the NO production by EAhy.926 cells under mechanical stress generated by the medium flow. The article presents the method for measuring NO production and the calculated hydrodynamic characteristics of the microfluidic system. The results showed that the developed microfluidic model system is promising for studying cell-autonomous regulatory properties of the endothelium both under the action of vasoactive agents and in simulated endothelial dysfunction.


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