Abstract 648: Nebivolol and Valsartan Increase Nitric Oxide Release from Human Endothelial Cells in a Synergistic Fashion

Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
R. Preston Mason ◽  
Robert F Jacob ◽  
Tadeusz Malinski

Introduction: Nebivolol is a β1-adrenergic receptor antagonist that stimulates endothelial nitric oxide (NO) release through β3-adrenergic receptor activation, ATP-mediated stimulation of purinergic P2Y receptors, and inhibition of membrane lipid oxidation. Valsartan is an angiotensin II receptor blocker (ARB) that selectively inhibits angiotensin II type 1 (AT1) receptors, thereby exerting no direct effect at type 2 (AT2) receptors, which have been shown to stimulate NO synthase activity through a bradykinin-mediated pathway. As NO is a key regulator of blood pressure and these two antihypertensive agents promote NO release through distinct mechanisms, we compared their individual and combined effects on NO release from human endothelial cells. Methods: Human umbilical vein endothelial cells (HUVECs) were incubated for 1 hr with vehicle, nebivolol or valsartan alone (each at 1.0 μM), or nebivolol (1.0 μM) and valsartan (0.5-5.0 μM) combined. The comparative effects of these agents on maximal NO release were measured in individual cells using porphyrinic nanosensors following stimulation with calcium ionophore (1.0 μM). Results: Nebivolol treatment increased HUVEC NO release by 49% (509 ± 18 nM, mean ± SD) as compared to vehicle treatment alone (342 ± 26 nM; p<0.001). Valsartan had a more modest effect, increasing NO release by 13% (385 ± 19 nM) as compared to vehicle-treated controls (p<0.01). Treatment with both agents at 1.0 μM increased HUVEC NO release by 91% (655 ± 19 nM) as compared to vehicle alone (p<0.001) and was 29% (p<0.001) and 70% (p<0.001) greater than the separate effects observed for nebivolol and valsartan, respectively. The additive effect of valsartan was dose-dependent and was also observed at 0.5 and 5.0 μM in combination with nebivolol. Conclusions: These data suggest that nebivolol and valsartan, when applied in combination, increase the ability of endothelial cells to release NO in a synergistic manner. The exact mechanism of this process remains unclear but, considering the importance of NO in regulating blood pressure, merits further study.

Endocrinology ◽  
2016 ◽  
Vol 157 (6) ◽  
pp. 2403-2415 ◽  
Author(s):  
Elena Grossini ◽  
Giulia Raina ◽  
Serena Farruggio ◽  
Lara Camillo ◽  
Claudio Molinari ◽  
...  

Des-acyl ghrelin (DAG), the most abundant form of ghrelin in humans, has been found to reduce arterial blood pressure and prevent cardiac and endothelial cell apoptosis. Despite this, data regarding its direct effect on cardiac function and coronary blood flow, as well as the related involvement of autonomic nervous system and nitric oxide (NO), are scarce. We therefore examined these issues using both in vivo and in vitro studies. In 20 anesthetized pigs, intracoronary 100 pmol/mL DAG infusion with a constant heart rate and aortic blood pressure, increased coronary blood flow and NO release, whereas reducing coronary vascular resistances (P &lt; .05). Dose responses to DAG were evaluated in five pigs. No effects on cardiac contractility/relaxation or myocardial oxygen consumption were observed. Moreover, whereas the blockade of muscarinic cholinoceptors (n = 5) or α- and β-adrenoceptors (n = 5 each) did not abolish the observed responses, NO synthase inhibition (n = 5) prevented the effects of DAG on coronary blood flow and NO release. In coronary artery endothelial cells, DAG dose dependently increased NO release through cAMP signaling and ERK1/2, Akt, and p38 MAPK involvement as well as the phosphorylation of endothelial NO synthase. In conclusion, in anesthetized pigs, DAG primarily increased cardiac perfusion through the involvement of NO release. Moreover, the phosphorylation of ERK1/2 and Akt appears to play roles in eliciting the observed NO production in coronary artery endothelial cells.


2001 ◽  
Vol 170 (2) ◽  
pp. 433-440 ◽  
Author(s):  
L Kalinowski ◽  
LW Dobrucki ◽  
T Malinski

Parathyroid hormone (PTH)-related protein (PTHrP) is produced in smooth muscles and endothelial cells and is believed to participate in the local regulation of vascular tone. No direct evidence for the activation of endothelium-derived nitric oxide (NO) signaling pathway by PTHrP has been found despite attempts to identify it. Based on direct in situ measurements, it is reported here for the first time that the human PTH/PTHrP receptor analogs, hPTH(1--34) and hPTHrP(1--34), stimulate NO release from a single endothelial cell. A highly sensitive porphyrinic microsensor with a response time of 0.1 ms and a detection limit of 1 nmol/l was used for the measurement of NO. Both hPTH(1--34) and hPTHrP(1--34) stimulated NO release at nanomolar concentrations. The peak concentration of 0.1 micromol/l hPTH(1--34)- and 0.1 micromol/l hPTHrP(1--34)-stimulated NO release was 175+/-9 and 248+/-13 nmol/l respectively. This represents about 30%--40% of maximum NO concentration recorded in the presence of (0.1 micromol/l) calcium ionophore. Two competitive PTH/PTHrP receptor antagonists, 10 micromol/l [Leu(11),d -Trp(12)]-hPTHrP(7--34)amide and 10 micromol/l [Nle(8,18),Tyr(34)]-bPTH(3--34)amide, were equipotent in antagonizing hPTH(1--34)-stimulated NO release; [Leu(11),d -Trp(12)]-hPTHrP(7--34)amide was more potent than [Nle(8,18),Tyr(34)]-bPTH(3--34)amide in inhibiting hPTHrP(1--34)-stimulated NO release. The PKC inhibitor, H-7 (50 micromol/l), did not change hPTH(1--34)- and hPTHrP(1--34)-stimulated NO release, whereas the combined effect of 10 micromol/l of the cAMP antagonist, Rp-cAMPS, and 50 micromol/l of the calmodulin inhibitor, W-7, was additive. The present studies show that both hPTH(1--34) and hPTHrP(1--34) activate NO production in endothelial cells. The activation of NO release is through PTH/PTHrP receptors and is mediated via the calcium/calmodulin pathway.


1998 ◽  
Vol 330 (2) ◽  
pp. 695-699 ◽  
Author(s):  
Frédérique LANTOINE ◽  
Lahcen IOUZALEN ◽  
Marie-Aude DEVYNCK ◽  
Elisabeth MILLANVOYE-van BRUSSEL ◽  
Monique DAVID-DUFILHO

The causal relationships between cytosolic free-Ca2+ concentration ([Ca2+]i) increases and production of nitric oxide (NO) have been investigated mostly with indirect methods and remain unclear. Here we demonstrate, by direct real-time measurements of [NO] with a porphyrinic microsensor, that Ca2+ entry, but not an increase in [Ca2+]i, is required for triggering of NO production in human endothelial cells. Histamine, ranging from 0.1 to 100 μM, increased both NO production and [Ca2+]i when given in a single dose. However, histamine caused increased NO release but induced progressively smaller [Ca2+]i changes when cumulatively added. In the absence of a transmembrane Ca2+ gradient, no significant NO release was detectable, despite the marked Ca2+ peak induced by histamine. Inhibition of Ca2+ entry by SK&F 96365 abolished histamine-elicited NO production but only reduced the transient [Ca2+]i rise. The suppression of the sustained [Ca2+]i response under these two conditions suggests that NO release was closely associated with Ca2+ entry from the extracellular space. In addition, membrane depolarization, achieved by increasing the extracellular K+ concentration from 5 to 130 mM, reduced both the amplitude of histamine-induced sustained [Ca2+]i elevation and NO production. These results lead us to propose that the availability of numerous Ca2+ ions around the internal side of the plasma membrane would promote the association between nitric oxide synthase and calmodulin, thereby activating the enzyme.


2008 ◽  
pp. 885-892
Author(s):  
AS Diallo ◽  
M Sarr ◽  
HA Mostefai ◽  
N Carusio ◽  
M Pricci ◽  
...  

We recently reported that in vitro Cognac polyphenolic compounds (CPC) induce NO-dependent vasorelaxant effects and stimulate cardiac function. In the present study, we aim to investigate the effect of CPC on both nitric oxide (NO) and superoxide anions (O(2)(-)) production in cultured human endothelial cells. In addition, its effect on the bradykinin (BK)-induced NO production was also tested. The role and sources of O(2)(-) in the concomitant effect of BK plus CPC were pharmacologically determined. NO and O(2)(-) signals were measured using electron paramagnetic resonance technique using specific spin trappings. Both, CPC and BK induced an increase in NO production in human endothelial cells. The combination of both further enhanced NO release. The capacity of CPC plus BK to increase NO signal was blunted by the NO synthase inhibitor, N(G)-nitro-L-arginine methyl ester, and was enhanced in the presence either of superoxide dismutase or catalase. Moreover, CPC plus BK response was greater after inhibition of either NADPH oxidase by apocynin or xanthine oxidase by allopurinol but it was not affected by rotenone. CPC did not affect O(2)(-) level either alone or after its increase upon lipopolysaccharide treatment. Finally, the capacity of BK alone to increase NO was enhanced either by apocynin or allopurinol. Altogether, these data demonstrate that CPC is able to directly increase NO production without affecting O(2)(-) and enhances the BK-induced NO production in human endothelial cells. The data highlight the ability of BK to stimulate not only NADPH oxidase- but also xanthine oxidase-inhibitor sensitive mechanisms that reduce its efficiency in increasing NO either alone or in the presence of CPC. These results bring pharmacological evidence for vascular protection by CPC via its potentiating effect of BK response in terms of endothelial NO release.


1993 ◽  
Vol 265 (3) ◽  
pp. C728-C732 ◽  
Author(s):  
D. Ghigo ◽  
P. Alessio ◽  
A. Foco ◽  
F. Bussolino ◽  
C. Costamagna ◽  
...  

Human endothelial cells cultured from umbilical vein (HUVEC) were tested for their ability to synthesize nitric oxide (NO), which has been identified as an endothelium-derived relaxing factor. The synthesis of this free radical (detected as citrulline, which is produced stoichiometrically with NO from arginine) in HUVEC is Ca2+ dependent, is increased sevenfold by the calcium ionophore ionomycin, and accounts for most basal and ionomycin-induced guanosine 3',5'-cyclic monophosphate (cGMP) production. Loading of cells with reduced glutathione (GSH), but not with N-(2-mercaptopropionyl)- glycine (MPG), led to increased citrulline production, both basally and after ionomycin stimulation. When the cells were depleted of GSH by incubation with 1-chloro-2,4-dinitrobenzene (CDNB), citrulline synthesis and cGMP production were inhibited in a concentration-dependent way. CDNB was not cytotoxic and did not inhibit cGMP increase elicited by sodium nitroprusside; cell loading with GSH (but not with MPG) relieved the block of citrulline synthesis. These results suggest that GSH is necessary in HUVEC for NO synthesis rather than for the NO effect on guanylate cyclase.


2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Preston Mason ◽  
Hazem Dawoud ◽  
Samuel Sherratt ◽  
Peter Libby ◽  
Deepak L Bhatt ◽  
...  

Treatment with prescription, high dose, stable icosapent ethyl (IPE), which is eicosapentaenoic acid (EPA), an omega-3 fatty acid (O3FA), significantly reduced clinical events in high-risk patients with diabetes and other risk factors or cardiovascular disease (REDUCE-IT). Previous studies suggest that the benefits of EPA correlate positively with its levels and ratio to arachidonic acid (AA) in circulation. Unlike EPA, AA is an omega-6 fatty acid (O6FA) that, along with its metabolites, contributes to inflammation and diabetes. One mechanism of benefit of an increased EPA to AA ratio may be improved endothelial cell (EC) function, as evidenced by increased nitric oxide (NO) release and decreased nitroxidative (ONOO – ) stress. In this study, human umbilical vein endothelial cells (HUVECs) were pretreated with EPA or AA at equimolar levels (10 μM) at various time points (4-24 hr) in 5% FBS. Following treatment, the cells were stimulated with calcium ionophore and assayed for the ratio of NO and ONOO – release, an indicator of eNOS coupling, using tandem porphyrinic nanosensors. ECs treated with EPA had significantly greater NO release following stimulation compared with vehicle at all time points, including 17% and 21% at 4 and 24 hr, respectively (p<0.05 and p<0.01) without changes in eNOS expression. By contrast, AA did not significantly improve NO production. ECs treated with EPA also showed a non-significant reduction in ONOO - release by 10% at 4 hr and 14% at 24 hr. EPA, but not AA, increased NO/ONOO - release ratio by 42% (4.03 ± 0.06 vs 2.83 ± 0.05; p <0.01) by 24 hr. Thus, EPA increased NO bioavailability in human ECs, unlike AA, due to improved eNOS coupling and reduced oxidative stress. These findings support a preferential benefit of EPA on endothelial function as compared to AA and supports further investigation.


2013 ◽  
pp. 351-359 ◽  
Author(s):  
L. XU ◽  
Y. LIU

We investigated the effects of telmisartan, the blocker of angiotensin II receptor 1, on the regulation of systolic blood pressure (SBP) and oxidative stress through endothelial nitric oxide (NO) release in spontaneously hypertensive rats (SHRs). SHRs randomly received placebo, oral feeding of telmisartan (5 mg/kg or 10 mg/kg) every day and Wistar-Kyoto rats (WKYs) served as normotensive control. The SBP of rat was measured before and weekly thereafter. After a total of 8-week treatment, rats were killed for experimental measurements. Parameters that subject to measurements in isolated aorta endothelial cells include: NO concentration, protein expression levels of angiotensin II receptor 1, nitrotyrosine, 8-isoprostane, SOD, PI3K, Akt, AMPK and eNOS. In addition, L-NMMA, a general inhibitor of nitric oxide synthase, was also applied to test the inhibition of NO concentration. We found that SBPs were significantly lower in telmisartan therapy group than in placebo treated hypertensive rats and WKYs (p<0.05). The NO concentration was significantly higher in telmisartan-treated group with increased activity of the PI3K/Akt pathway and activated eNOS signaling. Blockade of Akt activity reversed such effects. Activation of AMPK also contributed to the phosphorylation of eNOS. L-NMMA treatment reduced less NO concentration in SHR rats than the telmisartan co-treated groups. Oxidative stress in SHRs was also attenuated by telmisartan administration, shown by reduced formation of nitrotyrosine, 8-isoprostane, and recovered SOD protein level. Telmisartan enhanced NO release by activating the PI3K/Akt system, AMPK phosphorylation and eNOS expression, which attenuated the blood pressure and oxidative stress in SHRs.


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