scholarly journals A Betalain-rich Dietary Supplement, But Not PETN, Increases Vasodilation and Nitric Oxide: A Comparative, Single-dose, Randomized, Placebo-controlled, Blinded, Crossover Pilot Study

2020 ◽  
Vol 10 (1) ◽  
pp. 26
Author(s):  
B. V. Nemzer ◽  
Z. Pietrzkowski ◽  
J. M. Hunter ◽  
J. L. Robinson ◽  
B. Fink
Keyword(s):  
Nitric Oxide ◽  
Single Dose ◽  
Endothelial Function ◽  
Dietary Supplement ◽  
Athletic Performance ◽  
Side Reaction ◽  
Nitrate Content ◽  
Organic Nitrate ◽  
Experimental Conditions ◽  
Study Results

Nutraceutical supplements have demonstrated promise as agents for improving athletic performance and for positively affecting cardiovascular health and vigor through modulation of endothelial function at the cellular level. High-nitrate products, such as red beet juices and powders, have been observed to improve athletic performance potentially through increased nitric oxide (NO) concentrations in the blood. Similarly, a patented low nitrate, low sugar betalain-rich supplement has also been reported to significantly improve athletic performance. To the best of our knowledge, no acute clinical studies have been conducted that have demonstrated the comparative efficacies of high-nitrate or betalain-rich, low nitrate materials on measures of endothelial function in real time. In this acute single-dose, double-blinded, randomized, placebo-controlled, crossover study, we examined the effects of the betalain-rich low nitrate dietary supplement, (BRS, 50mg), in comparison to pentaerythritol tetranitrate (PETN, 40mg), a pharmaceutical drug that is a potent source of organic nitrate, and a placebo, on various measures of endothelial function for up to 4-hours post-ingestion. More specifically, in order to gauge post-treatment changes in endothelial function we measured flow-mediated dilation (FMD), nitrite (NO2)/nitrate (NO3) content, circulating nitrosyl-hemoglobin (NOHb) concentration, and cellular metabolic activity (CMA) measured as generation of reactive oxygen species, a side reaction of oxidative-reductive cellular metabolism. Ten participants completed all arms of the study. Results suggest that within 2 hours, BRS, but not PETN or placebo, resulted in significantly elevated levels of NOHb (a measure of bioavailable NO●) (p = 0.017) and increased vasodilation as measured by FMD, (p = 0.025). As expected, due to its high nitrate content, NO2/NO3 levels were increased by PETN within 2-hours (p = 0.048), but not by BRS or placebo. Finally, under these experimental conditions, PETN and BRS produced no significant changes for mitochondrial, NADPH-oxidase dependent or cellular CMA. These data provide preliminary support for single-dose effectiveness of BRS, but not PETN, on levels of bioavailable NO● and FMD, both important measures of endothelial function. Additionally, these data suggest potentially different mechanisms of action related to low nitrate BRS and organic nitrate PETN.

scholarly journals A Single Dose of Beetroot Gel Rich in Nitrate Does Not Improve Performance but Lowers Blood Glucose in Physically Active Individuals

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Julia Vasconcellos ◽  
Diego Henrique Silvestre ◽  
Diego dos Santos Baião ◽  
João Pedro Werneck-de-Castro ◽  
Thiago Silveira Alvares ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Single Dose ◽  
Serum Cortisol ◽  
Acute Effect ◽  
Peak Oxygen Consumption ◽  
Controlled Study ◽  
Nitrate Content ◽  
Nitric Oxide Synthesis ◽  
Double Blind ◽  
Physically Active

Background. Beetroot consumption has been proposed to improve exercise performance, since the nitrate content of this food is able to stimulate the synthesis of nitric oxide.Objective. The acute effect of 100 g of a beetroot gel containing ~10 mmol of nitrate was tested on the nitric oxide synthesis, on metabolic and biochemical parameters, and on performance in physically active individuals.Methods. Through a double blind, crossover, placebo-controlled study, 25 healthy runners ingested a single dose of beetroot and placebo gels. Participants performed an aerobic exercise protocol on a treadmill (3 min warm-up of 40% peak oxygen consumption, 4 min at 90% of gas exchange threshold I and 70% (Δ) maximal end speed until volitional fatigue).Results. Urinary levels of nitrite and nitrate increased after 90 min of beetroot gel ingestion. Plasma glucose concentrations lowered after the exercise and the decrease was maintained for 20 min. Systolic and diastolic blood pressures, serum cortisol, and blood lactate were not altered after the beetroot gel ingestion compared to a placebo gel.Conclusion. The single dose of beetroot gel provoked an increase of nitric oxide synthesis although no improvement on the physical performance of athletes during aerobic submaximal exercise was observed.

Therapeutic Potential of Phosphodiesterase Inhibitors for Endothelial Dysfunction- Related Diseases

2020 ◽  
Vol 26 (30) ◽  
pp. 3633-3651 ◽  
Author(s):  
Javier Blanco-Rivero ◽  
Fabiano E. Xavier
Keyword(s):  
Nitric Oxide ◽  
Endothelial Dysfunction ◽  
Endothelial Function ◽  
Therapeutic Potential ◽  
Treatment Strategies ◽  
Phosphodiesterase Inhibitors ◽  
Developed Countries ◽  
Major Health Problem ◽  
Pde Inhibitors ◽  
Pharmaceutical Industries

Cardiovascular diseases (CVD) are considered a major health problem worldwide, being the main cause of mortality in developing and developed countries. Endothelial dysfunction, characterized by a decline in nitric oxide production and/or bioavailability, increased oxidative stress, decreased prostacyclin levels, and a reduction of endothelium-derived hyperpolarizing factor is considered an important prognostic indicator of various CVD. Changes in cyclic nucleotides production and/ or signalling, such as guanosine 3', 5'-monophosphate (cGMP) and adenosine 3', 5'-monophosphate (cAMP), also accompany many vascular disorders that course with altered endothelial function. Phosphodiesterases (PDE) are metallophosphohydrolases that catalyse cAMP and cGMP hydrolysis, thereby terminating the cyclic nucleotide-dependent signalling. The development of drugs that selectively block the activity of specific PDE families remains of great interest to the research, clinical and pharmaceutical industries. In the present review, we will discuss the effects of PDE inhibitors on CVD related to altered endothelial function, such as atherosclerosis, diabetes mellitus, arterial hypertension, stroke, aging and cirrhosis. Multiple evidences suggest that PDEs inhibition represents an attractive medical approach for the treatment of endothelial dysfunction-related diseases. Selective PDE inhibitors, especially PDE3 and PDE5 inhibitors are proposed to increase vascular NO levels by increasing antioxidant status or endothelial nitric oxide synthase expression and activation and to improve the morphological architecture of the endothelial surface. Thereby, selective PDE inhibitors can improve the endothelial function in various CVD, increasing the evidence that these drugs are potential treatment strategies for vascular dysfunction and reinforcing their potential role as an adjuvant in the pharmacotherapy of CVD.

scholarly journals Adsorption Studies on Magnetic Nanoparticles Functionalized with Silver to Remove Nitrates from Waters

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1757
Author(s):  
Yesica Vicente-Martínez ◽  
Manuel Caravaca ◽  
Antonio Soto-Meca ◽  
Miguel Ángel Martín-Pereira ◽  
María del Carmen García-Onsurbe
Keyword(s):  
Magnetic Nanoparticles ◽  
Nitrate Content ◽  
Adsorption Efficiency ◽  
Experimental Conditions ◽  
Dependent Behavior ◽  
Before And After ◽  
Naoh Solution ◽  
High Concentrations ◽  
Interference Studies

This paper presents a novel procedure for the treatment of contaminated water with high concentrations of nitrates, which are considered as one of the main causes of the eutrophication phenomena. For this purpose, magnetic nanoparticles functionalized with silver (Fe3O4@AgNPs) were synthesized and used as an adsorbent of nitrates. Experimental conditions, including the pH, adsorbent and adsorbate dose, temperature and contact time, were analyzed to obtain the highest adsorption efficiency for different concentration of nitrates in water. A maximum removal efficiency of 100% was reached for 2, 5, 10 and 50 mg/L of nitrate at pH = 5, room temperature, and 50, 100, 250 and 500 µL of Fe3O4@AgNPs, respectively. The characterization of the adsorbent, before and after adsorption, was performed by energy dispersive X-ray spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller analysis and Fourier-transform infrared spectroscopy. Nitrates can be desorbed, and the adsorbent can be reused using 500 µL of NaOH solution 0.01 M, remaining unchanged for the first three cycles, and exhibiting 90% adsorption efficiency after three regenerations. A deep study on equilibrium isotherms reveals a pH-dependent behavior, characterized by Langmuir and Freundlich models at pH = 5 and pH = 1, respectively. Thermodynamic studies were consistent with physicochemical adsorption for all experiments but showed a change from endothermic to exothermic behavior as the temperature increases. Interference studies of other ions commonly present in water were carried out, enabling this procedure as very selective for nitrate ions. In addition, the method was applied to real samples of seawater, showing its ability to eliminate the total nitrate content in eutrophized waters.

Flow-mediated dilatation following wrist and upper arm occlusion in humans: the contribution of nitric oxide

2001 ◽  
Vol 101 (6) ◽  
pp. 629-635 ◽  
Author(s):  
Sagar N. DOSHI ◽  
Katerina K. NAKA ◽  
Nicola PAYNE ◽  
Christopher J.H. JONES ◽  
Moira ASHTON ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Function ◽  
Brachial Artery ◽  
Peak Flow ◽  
Ultrasound Probe ◽  
Upper Arm ◽  
Flow Mediated Dilatation ◽  
Synthase Inhibitor ◽  
Increased Blood Flow ◽  
Similar Peak

Flow-mediated dilatation (FMD) of the brachial artery assessed by high-resolution ultrasound is widely used to measure endothelial function. However, the technique is not standardized, with different groups using occlusion of either the wrist or the upper arm to induce increased blood flow. The validity of the test as a marker of endothelial function rests on the assumption that the dilatation observed is endothelium-dependent and mediated by nitric oxide (NO). We sought to compare the NO component of brachial artery dilatation observed following wrist or upper arm occlusion. Dilatation was assessed before and during intra-arterial infusion of the NO synthase inhibitor NG-monomethyl-l-arginine (l-NMMA) following occlusion of (i) the wrist (distal to ultrasound probe) and (ii) the upper arm (proximal to ultrasound probe) for 5min in ten healthy males. Dilatation was significantly greater after upper arm occlusion (upper arm, 11.62±3.17%; wrist, 7.25±2.49%; P = 0.003). During l-NMMA infusion, dilatation after wrist occlusion was abolished (from 7.25±2.49% to 0.16±2.24%; P < 0.001), whereas dilatation after upper arm occlusion was only partially attenuated (from 11.62±3.17% to 7.51±2.34%; P = 0.006). The peak flow stimulus was similar after wrist and upper arm occlusion. We conclude that dilatation following upper arm occlusion is greater than that observed after wrist occlusion, despite a similar peak flow stimulus. l-NMMA infusion revealed that FMD following wrist occlusion is mediated exclusively by NO, while dilatation following upper arm occlusion comprises a substantial component not mediated by NO, most probably related to tissue ischaemia around the brachial artery. FMD following wrist occlusion may be a more valid marker of endothelial function than dilatation following upper arm occlusion.

scholarly journals Simultaneous Assessment of Endothelial Function, Nitric Oxide Synthase Activity, Nitric Oxide–Mediated Signaling, and Oxidative Stress in Individuals with and without Hypercholesterolemia

2008 ◽  
Vol 54 (2) ◽  
pp. 292-300 ◽  
Author(s):  
Renke Maas ◽  
Edzard Schwedhelm ◽  
Lydia Kahl ◽  
Huige Li ◽  
Ralf Benndorf ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Function ◽  
Urinary Excretion ◽  
Indirect Evidence ◽  
No Oxidation ◽  
Whole Body ◽  
Gas Chromatography Mass Spectrometry ◽  
Synthesis Rate ◽  
No Production

Abstract Background: Endothelial function is impaired in hypercholesterolemia and atherosclerosis. Based on mostly indirect evidence, this impairment is attributed to reduced synthesis or impaired biological activity of endothelium-derived nitric oxide (NO). It was the aim of this study to directly estimate and compare whole-body NO production in normo- and hypercholesterolemia by applying a nonradioactive stable isotope dilution technique in vivo. Methods: We enrolled 12 normocholesterolemic and 24 hypercholesterolemic volunteers who were all clinically healthy. To assess whole-body NO synthesis, we intravenously administered l-[guanidino-(15N2)]-arginine and determined the urinary excretion of 15N-labeled nitrate, the specific end product of NO oxidation in humans, by use of gas chromatography-mass spectrometry. In addition, we measured flow-mediated vasodilation (FMD) of the brachial artery, expression of endothelial NOS (eNOS) in platelets, plasma concentration of the endogenous NOS inhibitor asymmetric dimethylarginine (ADMA), and urinary excretion of 8-isoprostaglandin F2α (8-iso-PGF2α). Results: After infusion of l-[guanidino-(15N2)]-arginine, cumulative excretion of 15N-labeled-nitrate during 48 h was 40% [95% CI 15%–66%] lower in hypercholesterolemic than normocholesterolemic volunteers [mean 9.2 (SE 0.8) μmol vs 15.4 (2.3) μmol/l, P = 0.003]. FMD was on average 36% [4%–67%] lower in hypercholesterolemic than normocholesterolemic volunteers [6.3 (4.0)% vs 9.4 (4.6)%, P = 0.027]. Normalized expression of NOS protein in platelets was also significantly lower in hypercholesterolemic volunteers, whereas there were no significant differences in plasma ADMA concentration or urinary excretion of 8-iso-PGF2α between the 2 groups. Conclusions: This study provides direct evidence for a decreased whole body NO synthesis rate in healthy people with hypercholesterolemia.

Follow-Up Study on Management of Tumour Lysis Syndrome with Single Low Fixed Dose (1.5 mg) of Rasburicase - A Tertiary Cancer Centre Experience from India

2021 ◽  
Vol 8 (25) ◽  
pp. 2149-2154
Author(s):  
Alok Ranjan ◽  
Nisha Khanna ◽  
Vivek Ranjan ◽  
Ashwin Kumar
Keyword(s):  
Uric Acid ◽  
Single Dose ◽  
Tumour Lysis Syndrome ◽  
Urate Oxidase ◽  
Fixed Dose ◽  
Additional Dose ◽  
Tumour Lysis ◽  
Follow Up Study ◽  
Study Results

BACKGROUND Rasburicase (recombinant urate oxidase) has been proven to be an effective therapy for prevention of tumour lysis syndrome (TLS). The recommended daily dosing regimen of rasburicase is 0.2 mg/kg/day for 5 days which is expensive and unaffordable to many patients in the developing countries. The purpose of the present study was to evaluate the effect of single 1.5 mg dose rasburicase in the management of tumour lysis syndrome. METHODS This is a follow-up study done at our institute. Fifty (50) patients with tumour lysis syndrome who received rasburicase from August 2015 to January 2020 were enrolled in this study RESULTS Single dose of rasburicase is effective in decreasing serum uric acid level in significant number (N = 41) of patients. Percentage of patients having uric acid less than 7 mg after single dose of rasburicase in 48 hours - 82.9 % (N = 34) while 17 % (N = 7) were found to have uric acid levels of more than 7 mg/dl. The percentage of patients with uric acid levels more than 7 mg/dl reduced from 36.5 % after 24 hours to 17 % after 48 hours. This indicates that the uric acid levels show a declining trend even after 24 hours without giving an additional dose of rasburicase. There was no relationship between uric acid levels at 24 hours and percentage change in creatinine level from baseline to 24 hours (correlation coefficient (r) = -0.047, P = 0.770. Patients who required additional dose (N = 9) had high base line value of uric acid and their high value was maintained over the follow up period of three days. Patients with pre exiting kidney disease and high level of baseline uric acid also needed dialysis (N = 3). CONCLUSIONS In majority of patients, a single 1.5 mg dose of rasburicase is an effective way to reduce raised uric acid in appropriate circumstances. KEYWORDS Single Dose, Recombinant Urate Oxidase, Uric Acid, Leukemia, Tumour Lysis Syndrome, Rasburicase

Flow-mediated dilation does/does not reflect nitric oxide-mediated endothelial function

2005 ◽  
Vol 99 (4) ◽  
pp. 1621-1621 ◽  
Author(s):  
Clare E. Austin
Keyword(s):  
Nitric Oxide ◽  
Endothelial Function ◽  
Flow Mediated Dilation ◽  
September Issue

This letter is in response to the Point:Counterpoint series “Flow-mediated dilation does/does not reflect nitric oxide-mediated endothelial function” that appeared in the September issue (vol. 99: 1233–1238, 2005; doi:10.1152/japplphysiol.00601.2005; http://jap.physiology.org/content/vol99/issue3/2005 ).

Inhibition of tetrahydrobiopterin biosynthesis impairs endothelium-dependent relaxations in canine basilar artery

1997 ◽  
Vol 273 (2) ◽  
pp. H718-H724 ◽  
Author(s):  
H. Kinoshita ◽  
S. Milstien ◽  
C. Wambi ◽  
Z. S. Katusic
Keyword(s):  
Nitric Oxide ◽  
Superoxide Dismutase ◽  
Nitric Oxide Synthase ◽  
Endothelial Function ◽  
Isometric Force ◽  
Cerebral Arteries ◽  
Calcium Ionophore ◽  
Nitric Oxide Donor ◽  
Ionophore A23187 ◽  
Oxide Synthase

Tetrahydrobiopterin is an essential cofactor in biosynthesis of nitric oxide. The present study was designed to determine the effect of decreased intracellular tetrahydrobiopterin levels on endothelial function of isolated cerebral arteries. Blood vessels were incubated for 6 h in minimum essential medium (MEM) in the presence or absence of a GTP cyclohydrolase I inhibitor, 2,4-diamino-6-hydroxypyrimidine (DAHP, 10(-2) M). Rings with and without endothelium were suspended for isometric force recording in the presence of a cyclooxygenase inhibitor, indomethacin (10(-5) M). In arteries with endothelium, DAHP significantly reduced intracellular levels of tetrahydrobiopterin. DAHP in combination with a precursor of the salvage pathway of tetrahydrobiopterin biosynthesis, sepiapterin (10(-4) M), not only restored but increased levels of tetrahydrobiopterin above control values. In DAHP-treated arteries, endothelium-dependent relaxations to bradykinin (10(-10)-10(-6) M) or calcium ionophore A23187 (10(-9)-10(-6) M) were significantly reduced, whereas endothelium-independent relaxations to a nitric oxide donor, 3-morpholinosydnonimine (10(-9)-10(-4) M), were not affected. When DAHP-treated arteries with endothelium were incubated with sepiapterin (10(-4) M) or superoxide dismutase (150 U/ml), relaxations to bradykinin and A23187 were restored to control levels. In contrast, superoxide dismutase did not affect endothelium-dependent relaxations in arteries incubated in MEM. A nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (10(-4) M), abolished relaxations to bradykinin or A23187 in control arteries and in DAHP-treated arteries. These studies demonstrate that in cerebral arteries, decreased intracellular levels of tetrahydrobiopterin can reduce endothelium-dependent relaxations. Production of superoxide anions during activation of dysfunctional endothelial nitric oxide synthase appears to be responsible for the impairment of endothelial function.

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