Changes in body posture alter plasma nitrite but not nitrate concentration in humans

Liddle, Luke; Monaghan, Christopher; Burleigh, Mia; McIlvenna, Luke C; Muggeridge, David J.; Easton, Chris

doi:10.1016/j.niox.2017.11.008

Cited by 22 publications

(15 citation statements)

References 49 publications

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“…Nitrite and nitrate concentrations were evaluated in plasma and in the mouth rinse supernatants. Plasma samples were thawed and deproteinized (200 μL of the sample, 400 μL of zinc sulphate in deionized water at 10% weight/volume and 400 μL of 1 M sodium hydroxide in deionized water) for the determination of nitrate in order to avoid scum interferences during the determination [ 35 ]. The determination of nitrate and nitrite in the mouth rinse supernatants and of nitrite in plasma were performed directly without deproteinization.…”

Section: Methodsmentioning

confidence: 99%

Oral Administration of Sodium Nitrate to Metabolic Syndrome Patients Attenuates Mild Inflammatory and Oxidative Responses to Acute Exercise

Capó

Ferrer

Olek³

et al. 2020

Antioxidants

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The beneficial effects of exercise for the treatment and prevention of metabolic syndrome pathologies have been related to its anti-inflammatory and antioxidant effects. Dietary nitrate supplementation is an emerging treatment strategy to alleviate the symptoms of metabolic syndrome affections and to improve vascular function. In this double-blind crossover trial, metabolic syndrome patients performed two exercise tests for 30 min at 60–70% maximal heart rate after the intake of a placebo or a nitrate-enriched beverage. Acute exercise increased the plasma concentration of TNFα, intercellular adhesion molecule ICAM1, PGE1, PGE2 and the newly detected 16-hydroxypalmitic acid (16-HPAL) in metabolic syndrome patients. The cytokine and oxylipin production by peripheral blood mononuclear cells (PBMCs) and neutrophils could be responsible for the plasma concentrations of TNFα and IL6, but not for the plasma concentration of oxylipins nor its post-exercise increase. The intake of sodium nitrate 30 min before exercise increased the concentration of nitrate and nitrite in the oral cavity and plasma and reduced the oxygen cost of exercise. Additionally, nitrate intake prevented the enhancing effects of acute exercise on the plasma concentration of TNFα, ICAM1, PGE1, PGE2 and 16-HPAL, while reducing the capabilities of PBMCs and neutrophils to produce oxylipins.

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Section: Methodsmentioning

confidence: 99%

Oral Administration of Sodium Nitrate to Metabolic Syndrome Patients Attenuates Mild Inflammatory and Oxidative Responses to Acute Exercise

Capó

Ferrer

Olek³

et al. 2020

Antioxidants

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“…The high levels of urinary nitrite found (∼1.12 mmol L −1 and 4.28 mmol L −1 for urine 1 and 2, respectively) may indicate urinary infection, since the positive nitrite result arises from the ability of bacteria to convert nitrate in nitrite species into the renal tissue . In plasma and serum, nitrite levels are not well defined, changing according to the body‘s situations, such as the intake of foods rich in nitrates and nitrites .…”

Section: Resultsmentioning

confidence: 99%

Carbon‐nanotube Modified Screen‐printed Electrode for the Simultaneous Determination of Nitrite and Uric Acid in Biological Fluids Using Batch‐injection Amperometric Detection

et al. 2018

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A portable electroanalytical system applied for rapid and simultaneous determination of uric acid (UA) and nitrite (NIT) in human biological fluids (urine, saliva and blood) is reported. The system is based on batch‐injection analysis with multiple‐pulse amperometric (BIA‐MPA) detection using screen‐printed electrodes (SPEs) modified with multi‐walled carbon nanotubes. Sample dilution in optimized electrolyte (0.1 mol L−1 Britton‐Robinson buffer pH 2) followed by injection of 100 μL on the electrode surface using an electronic micropipette is performed. UA is detected at +0.45 V and both UA+NIT at +0.70 V. Linear calibration plots for UA and NIT were obtained over the range of 1–500 μmol L−1 with detection limits of 0.05 and 0.06 μmol L−1, respectively. For comparison, a differential‐pulse voltammetric (DPV) method was optimized, and linear calibration plots for UA and NIT were obtained over range of 1–30 μmol L−1 and 1–40 μmol L−1 with detection limits of 0.1 and 0.3 μmol L−1, respectively. BIA‐MPA is highly precise (RSD<1.3 %), fast (160 h−1) and free from sample‐matrix interferences as recovery values ranged from 77 to 121 % for spiked samples (short contact time of sample aliquot with SPE). Contrarily, recovery tests conducted using DPV did not provide adequate recovery values (>150 %), probably due to the longer contact time of the SPE with the biological samples during analysis leading to a severe interference of sample matrices.

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“…This may have limited any further biologically significant reductions in BP following UV-A exposure. Recently, we have shown that posture and the period of time of lying supine can alter both BP and plasma [NO 2 − ] (Liddle et al 2018 ), which emphasizes that posture should be carefully considered when conducting future research in this area.…”

Section: Methodsmentioning

confidence: 99%

The effects of two different doses of ultraviolet-A light exposure on nitric oxide metabolites and cardiorespiratory outcomes

et al. 2018

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PurposeThe present study investigated different doses of ultraviolet-A (UV-A) light on plasma nitric oxide metabolites and cardiorespiratory variables.MethodsTen healthy male participants completed three experimental conditions, 7 days apart. Participants were exposed to no light (CON); 10 J cm2 (15 min) of UV-A light (UVA10) and 20 J cm2 (30 min) of UV-A light (UVA20) in a randomized order. Plasma nitrite [NO2−] and nitrate [NO3−] concentrations, blood pressure (BP), and heart rate (HR) were recorded before, immediately after exposure and 30 min post-exposure. Whole body oxygen utilization (), resting metabolic rate (RMR) and skin temperature were recorded continuously.ResultsNone of the measured parameters changed significantly during CON (all P > 0.05). and RMR were significantly reduced immediately after UVA10 (P < 0.05) despite no change in plasma [NO2−] (P > 0.05). Immediately after exposure to UVA20, plasma [NO2−] was higher (P = 0.014) and and RMR tended to be lower compared to baseline (P = 0.06). There were no differences in [NO2−] or at the 30 min time point in any condition. UV-A exposure did not alter systolic BP, diastolic BP or MAP (all P > 0.05). UV-A light did not alter plasma [NO3−] at any time point (all P > 0.05).ConclusionsThis study demonstrates that a UV-A dose of 20 J cm2 is necessary to increase plasma [NO2−] although a smaller dose is capable of reducing and RMR at rest. Exposure to UV-A did not significantly reduce BP in this cohort of healthy adults. These data suggest that exposure to sunlight has a meaningful acute impact on metabolic function.

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Changes in body posture alter plasma nitrite but not nitrate concentration in humans

Abstract: Changing body posture causes rapid and consistent alterations in plasma [NO]. Researchers should therefore carefully consider the effect of posture when measuring this variable.

Cited by 22 publications

References 49 publications

Oral Administration of Sodium Nitrate to Metabolic Syndrome Patients Attenuates Mild Inflammatory and Oxidative Responses to Acute Exercise

Oral Administration of Sodium Nitrate to Metabolic Syndrome Patients Attenuates Mild Inflammatory and Oxidative Responses to Acute Exercise

Carbon‐nanotube Modified Screen‐printed Electrode for the Simultaneous Determination of Nitrite and Uric Acid in Biological Fluids Using Batch‐injection Amperometric Detection

The effects of two different doses of ultraviolet-A light exposure on nitric oxide metabolites and cardiorespiratory outcomes

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