Increased Plasma Nitrate Research Articles

Beet supplementation mitigates post-exercise inflammation.

This study investigated the efficacy of a mixed beet-based supplement (BEET) versus placebo (PL) in countering inflammation during recovery from 2.25 h of intensive cycling in 20 male and female cyclists. A multi-omics approach was used that included untargeted proteomics and a targeted oxylipin panel. A randomized, placebo-controlled, double-blind, crossover design was used with two 2-week supplementation periods and a 2-week washout period. Supplementation periods were followed by a 2.25 h cycling bout at close to 70%VO2max. The BEET supplement provided 212 mg of nitrates per day, 200 mg caffeine from green tea extract, 44 mg vitamin C from Camu Camu berry, B-vitamins from quinoa sprouts (40% Daily Value for thiamin, riboflavin, niacin, and vitamin B6), and 2.5 g of a mushroom blend containing Cordyceps sinensis and Inonotus obliquus. Six blood samples were collected before and after supplementation (overnight fasted state), immediately post-exercise, and at 1.5 h-, 3 h-, and 24 h-post-exercise. The 2.25 h cycling bout increased plasma levels of 41 of 67 oxylipins detected. BEET supplementation significantly increased plasma nitrate (NO3 -) and nitrite (NO2 -) (sum, NO3 - + NO2 -) concentrations (interaction effect, p < 0.001) and two anti-inflammatory oxylipins [18-hydroxyeicosapentaenoic acid (18-HEPE) and 4-hydroxy-docosahexanoic acid (4-HDoHE)]. The untargeted proteomics analysis identified 616 proteins (458 across all times points), and 2-way ANOVA revealed a cluster of 45 proteins that were decreased and a cluster of 21 that were increased in the BEET versus PL trials. Functional enrichment supported significant BEET-related reductions in inflammation-related proteins including several proteins related to complement activation, the acute phase response, and immune cell adhesion, migration, and differentiation. Intake of a BEET-based supplement during a 2-week period was linked to higher plasma levels of NO3 - + NO2 -, elevated post-exercise levels of two anti-inflammatory oxylipins, and a significant decrease in a cluster of proteins involved in complement activation and inflammation. These data support that 2-weeks intake of nitrate from a mixed beet-based supplement moderated protein biomarkers of exercise-induced inflammation in athletes.

Dietary nitrate supplementation to enhance exercise capacity in patients with COPD: Evidence from a meta-analysis of randomized controlled trials and a network pharmacological analysis

ObjectiveThe potential effects of nitrate in patients with chronic obstructive pulmonary disease (COPD) have attracted increased research interest. However, previous clinical trials have reported inconsistent results, and consecutive meta-analyses have failed to reach a consensus. Since some randomized controlled trials have recently been conducted that can provide more evidence, we performed an updated meta-analysis. MethodsA comprehensive literature search was conducted using PubMed, the Cochrane Library, Embase, and Web of Science databases to identify trials that assessed the efficacy and safety of nitrate in patients with COPD. The Revman 5.3 software was used for data analysis. Mean difference (MD) or standardized mean difference (SMD) with 95 % confidence interval (CI) was used as the effect measure, and forest plots were used to display individual and pooled results. Network pharmacology analysis was conducted to investigate the potential mechanisms of nitrate action in COPD. ResultsEleven studies involving 287 patients were included in this meta-analysis. The results indicated that dietary nitrate supplementation increased plasma nitrate and nitrite concentrations and fractional exhaled nitric oxide in patients with COPD. Nitrate improved exercise capacity [SMD = 0.38, 95 % CI = 0.04–0.72] and endothelial function [MD = 9.41, 95 % CI = 5.30–13.52], and relieved dyspnea in patients with COPD. Network pharmacology identified AKT1, IL1B, MAPK3, and CASP3 as key treatment targets. ConclusionDietary nitrate supplementation could be used as a potential treatment for patients with COPD, especially to increase their exercise capacity. The underlying mechanisms may be related to AKT1, IL1B, MAPK3, and CASP3.

Low Carbohydrate, High Fat Diet Alters the Oral Microbiome without Negating the Nitrite Response to Beetroot Juice Supplementation.

A low carbohydrate, high fat (LCHF) diet in athletes increases fat oxidation but impairs sports performance, potentially due to impaired exercise economy. Dietary nitrate supplementation can improve exercise economy via an increase in nitric oxide production, which is initiated by the reduction of nitrate to nitrite within the oral cavity. This reaction is dependent on the presence of nitrate-reducing oral bacteria, which can potentially be altered by dietary changes, including a LCHF diet. This study explored the effect of a LCHF diet on the oral microbiome and subsequent changes to plasma nitrite concentration following nitrate supplementation. Following five days of LCHF or high carbohydrate (HCHO) control dietary intervention, highly trained male race walkers consumed 140 mL beetroot juice containing 8.4 mmol nitrate; they then provided (a) blood samples for plasma nitrate and nitrite analysis and (b) saliva samples for 16S rRNA sequencing of the oral microbiome. The LCHF diet (n = 13) reduced oral bacterial diversity and changed the relative abundance of the genera Neisseria (+10%), Fusobacteria (+3%), Prevotella (-9%), and Veillonella (-4%), with no significant changes observed following the HCHO diet (n = 11). Following beetroot juice ingestion, plasma nitrite concentrations were higher for the LCHF diet compared to the HCHO diet (p = 0.04). However, the absence of an interaction with the trial (pre-post) (p = 0.71) suggests that this difference was not due to the dietary intervention. In summary, we found an increase in plasma nitrate and nitrite concentrations in response to nitrate supplementation independent of diet. This suggests the oral microbiome is adaptive to dietary changes and can maintain a nitrate reduction capacity despite a decrease in bacterial diversity following the LCHF diet.

A Novel Dual-Function Nitric Oxide Donor Therapy for Preeclampsia-A Proof-of-Principle Study in a Murine Model.

Background: Preeclampsia (PE) is a hypertensive disorder of pregnancy that is associated with substantial morbidity and mortality for the mother and fetus. Reduced nitric oxide bioavailability and oxidative stress contribute to the maternal and fetal pathophysiology of PE. In this study, we evaluated the efficacy of a novel dual-function nitric oxide donor/redox modulator, AKT-1005, in reducing PE symptoms in a mouse model of PE. Method: The potential therapeutic effect of AKT-1005 was tested in an animal model of Ad.sFlt-1-induced hypertension, proteinuria and glomerular endotheliosis, a model of PE. Pregnant Ad.sFlt-1-overexpressing CD1 mice were randomized into groups administered AKT-1005 (20 mg/kg) or a vehicle using a minipump on gd11 of pregnancy, and the impact on blood pressure and renal and placental damage were assessed. Results: In healthy female mice, ex vivo treatment of resistance vessels with AKT-1005 induced vasorelaxation, and 6 days of treatment in vivo did not significantly alter blood pressure with or without pregnancy. When given for 6 days during pregnancy along with Ad.sFlt-1-induced PE, AKT-1005 significantly increased plasma nitrate levels and reduced hypertension, renal endotheliosis and plasma cystatin C. In the placenta, AKT-1005 improved placental function, with reduced oxidative stress and increased endothelial angiogenesis, as measured by CD31 staining. As such, AKT-1005 treatment attenuated the Ad.sFlt-1-induced increase in placental and free plasma soluble endoglin expression. Conclusions: These data suggest that AKT-1005 significantly attenuates the sFlt-1-induced PE phenotypes by inhibiting oxidative stress, the anti-angiogenic response, and increasing NO bioavailability. Additional research is warranted to investigate the role of AKT-1005 as a novel therapeutic agent for vascular disorders such as preeclampsia.

Plasma Nitrate and Nitrite Kinetics after Single Intake of Beetroot Juice in Adult Patients on Chronic Hemodialysis and in Healthy Volunteers: A Randomized, Single-Blind, Placebo-Controlled, Crossover Study

Nitric oxide (NO) contributes to maintaining normal cardiovascular and renal function. This bioactive signalling molecule is generally formed enzymatically by NO synthase in the vascular endothelium. NO bioactivity can also be attributed to dietary intake of inorganic nitrate, which is abundant in our diet, especially in green leafy vegetables and beets. Ingested nitrate is reduced to nitrite by oral commensal bacteria and further to NO systemically. Previous studies have shown that dialysis, by means of removing nitrate and nitrite from the body, can reduce NO bioactivity. Hence, dietary intervention approaches aimed to boost the nitrate–nitrite–NO pathway may be of benefit in dialysis patients. The purpose of this study was to examine the kinetics of plasma nitrate and nitrite after a single intake of nitrate-rich concentrated beetroot juice (BJ) in adult hemodialysis (HD) patients and in age-matched healthy volunteers (HV). Eight HD patients and seven HV participated in this single center, randomized, single-blind, placebo-controlled, crossover study. Each participant received a sequential single administration of active BJ (70 mL, 400 mg nitrate) and placebo BJ (70 mL, 0 mg nitrate) in a random order separated by a washout period of seven days. For the kinetic analysis, blood samples were collected at different time-points before and up to 44 h after BJ intake. Compared with placebo, active BJ significantly increased plasma nitrate and nitrite levels both in HD patients and HV. The area under the curve and the maximal concentration of plasma nitrate, but not of nitrite, were significantly higher in HD patients as compared with HV. In both groups, active BJ ingestion did not affect blood pressure or plasma potassium levels. Both BJs were well tolerated in all participants with no adverse events reported. Our data provide useful information in planning dietary nitrate supplementation efficacy studies in patients with reduced NO bioactivity.

Corticosterone and Adrenocorticotrophic Hormone Secretion Is Recovered after Immune Challenge or Acute Restraint Stress in Sepsis Survivor Animals

Background: Clinical and experimental studies report a dysregulation of hypothalamus-pituitary-adrenal (HPA) axis during sepsis that causes impairment in hormone secretion in the late phase contributing for the pathophysiology of the disease. However, it is unclear whether this alteration persists even after the disease remission. Methods: We evaluated the effect of an immune challenge or restraint stress on the hormone secretion of HPA axis in sepsis survivor rats. Sepsis was induced by cecal ligation-puncture (CLP) surgery. Naive or animals that survive 5 or 10 days after CLP were submitted to lipopolysaccharide (LPS) injection or restraint stress. After 60 min, blood was collected for plasma nitrate, cytokines, adrenocorticotropic hormone (ACTH), and corticosterone (CORT) and brain for synaptophysin and hypothalamic cytokines. Results: Five days survivor animals showed increased plasma nitrate (p < 0.001) and interleukin (IL)-1β levels (p < 0.05) that were abolished in the 10 days survivors. In the hypothalamus of both survivors, the reverse was seen with IL-6 increased (p < 0.01), while IL-1β did not show any alteration. Synaptophysin expression was reduced in both survivors and did not change after any stimuli. Only the LPS administration increased plasma and/or inflammatory mediators levels in both groups (survivors and naive) being apparently lower in the survivors. There was no difference in the increased secretion pattern of ACTH and CORT observed in the naive and sepsis survivor animals submitted to immune challenge or restraint stress. Conclusion: We conclude that the HPA axis is already recovered soon after 5 days of sepsis induction responding with normal secretion of ACTH and CORT when required.

Acute Effects of Dietary Nitrate on Exercise Tolerance, Muscle Oxygenation, and Cardiovascular Function in Patients With Peripheral Arterial Disease

Previous studies have used supplements to increase dietary nitrate intake in clinical populations. Little is known about whether effects can also be induced through vegetable consumption. Therefore, the aim of this study was to assess the impact of dietary nitrate, through nitrate-rich vegetables (NRV) and beetroot juice (BRJ) supplementation, on plasma nitrate and nitrite concentrations, exercise tolerance, muscle oxygenation, and cardiovascular function in patients with peripheral arterial disease. In a randomized crossover design, 18 patients with peripheral arterial disease (age: 73 ± 8years) followed a nitrate intake protocol (∼6.5mmol) through the consumption of NRV, BRJ, and nitrate-depleted BRJ (placebo). Blood samples were taken, blood pressure and arterial stiffness were measured in fasted state and 150min after intervention. Each intervention was followed by a maximal walking exercise test to determine claudication onset time and peak walking time. Gastrocnemius oxygenation was measured by near-infrared spectroscopy. Blood samples were taken and blood pressure was measured 10min after exercise. Mean plasma nitrate and nitrite concentrations increased (nitrate; Time × Intervention interaction; p < .001), with the highest concentrations after BRJ (494 ± 110μmol/L) compared with NRV (202 ± 89μmol/L) and placebo (80 ± 19μmol/L; p < .001). Mean claudication onset time and peak walking time did not differ between NRV (413 ± 187s and 745 ± 220s, respectively), BRJ (392 ± 154s and 746 ± 176s), and placebo (403 ± 176s and 696 ± 222s) (p = .762 and p = .165, respectively). Gastrocnemius oxygenation, blood pressure, and arterial stiffness were not affected by the intervention. NRV and BRJ intake markedly increase plasma nitrate and nitrite, but this does not translate to improved exercise tolerance, muscle oxygenation, and/or cardiovascular function.

Role of nitric oxide on zymosan-induced inhibition of crop emptying in chicks

Zymosan, a component of yeast cell walls, reduces feed passage through the digestive tract in chicks (Gallus gallus), although the mechanism mediating this effect is poorly understood. Nitric oxide (NO) is associated with a variety of biological actions including effects on the immune system. In addition, it has been suggested that NO is involved in relaxation of the digestive tract and affects feed passage in mammals. It is therefore possible that NO might be related to zymosan-induced reduction of feed passage in chicks. However, the role of NO on the effect of zymosan feed passage has not been clarified yet. Thus, the purpose of the present study was to investigate whether NO is associated with zymosan-induced alteration of feed passage in chicks. Intraperitoneal (IP) injection of zymosan significantly increased plasma nitrate and nitrite (NOx) concentrations at 6 h after injection. Zymosan-induced elevation of plasma NOx concentration was abolished by co-injection of S-methylisothiourea (SMT), a selective inhibitor for inducible NO synthase (iNOS), indicating that zymosan facilitated the induction of iNOS. Furthermore, because zymosan increased iNOS mRNA expression in the digestive tract, NO is likely associated with the effect of zymosan on the digestive tract. IP injection of NO donors significantly decreased crop emptying rate, suggesting that NO functions as an inhibitor of crop emptying. This result implied that zymosan stimulates NO production by the induction of iNOS in the digestive tract and thereby inhibits crop emptying rate. However, the co-injection of SMT did not attenuate the inhibitory effect of zymosan on crop emptying. The present study provides evidence that some changes in the digestive tract caused by zymosan are mediated by iNOS-induced NO in chicks, but NO does not mediate the effect of zymosan on feed passage through the crop.

Dietary Nitrate Does Not Increase Exercising Muscle Blood Flow In Rat With Pulmonary Arterial Hypertension

PURPOSE: Pulmonary arterial hypertension (PAH) is a disease characterized by pulmonary artery remodeling, right ventricular hypertrophy, and exercise intolerance. We have previously found a significant reduction in skeletal muscle blood flow during exercise in a rat model of PAH, accompanied by an increase in blood lactate. In an attempt to increase flow, we administered beetroot juice (BRJ) to severely afflicted PAH rats, as BRJ has previously been shown to be effective in animal models and patient populations. METHODS: Male Sprague Dawley rats (n=18, 200-250 g) were injected with 60 mg/kg monocrotaline to elicit a severe PAH phenotype. At 3 wk post-injection, rats performed two trials of a VO2max treadmill test 2 h after oral gavage of a single dose (1 mmol/kg) of BRJ (BRJ, n=9), or placebo (PL, n=9), in counterbalanced order. Three days later, rats performed a final treadmill run 2 h after gavage of either BRJ or PL, in which fluorescent microspheres were administered during running (at 50% VO2max) to determine skeletal muscle blood flow. Nitrate and nitrite concentrations in plasma and skeletal muscle samples were determined via HPLC, whereas muscle cGMP was measured using ELISA. RESULTS: As expected, MCT induced impaired exercise tolerance with a 26+/- 6% (+/-SE) reduction in VO2max at 3 wk post-injection, that was not improved with BRJ (p=0.15). BRJ significantly increased plasma nitrate (p=<0.001) and nitrite (p=0.002) compared to PL; however only nitrate was elevated in the soleus (p=0.006) and vastus lateralis (p=0.02) by BRJ, with no significant differences in nitrite (p=0.13-0.66) or cGMP (p=0.08-0.68). BRJ did not increase blood flow in any of the 8 muscles sampled when compared to PL (p=0.23-0.96), nor did it reduce lactate accumulation during exercise (p=0.37). CONCLUSIONS: A single dose of dietary nitrate does not enhance exercising muscle blood flow or VO2max in a PAH rat, despite significantly increasing plasma nitrate and nitrite. This may be explained by a lack of efficacy in BRJ increasing muscle nitrite and cGMP, known mediators of the nitric oxide pathway and tissue perfusion. Future work should examine mechanisms for reduced skeletal muscle blood flow and further exploration of nitric oxide signaling in PAH patients. Funding: NIH HL121661 (MB Brown) and AG053606 (AR Coggan)

Vegetables with High-Nitrate Content Significantly Increase Plasma Nitrate and Nitrite Concentrations but Do Not Significantly Reduce Systolic Blood Pressure in Young Healthy Men

Aims: To investigate the effects of supplementation with high-nitrate and low-nitrate vegetables on plasma nitrate and nitrite concentrations, blood pressure and the oxygen demand of moderate-intensity exercise.&#x0D; Study Design: A randomized, cross-over design.&#x0D; Place and Duration of Study: Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, between January 2011 and March 2012.&#x0D; Methodology: 15 non-smoking, physically active healthy men (age 25 ± 6 years, BMI 24 ± 4 kg/m2) were randomized to receive a 2-week supply of high-nitrate or low-nitrate vegetables, with a 2-week ‘wash-out’ period in between. Clinic blood pressure, plasma nitrate and nitrite concentrations and physiological responses to moderate-intensity exercise tests were measured before and after each 2-week intervention. Nitrate intake was calculated using nutritional analysis of reported vegetables consumed.&#x0D; Results: Participants consumed significantly more dietary nitrate on the high-nitrate diet (417 ± 139 mg/day) than the low-nitrate diet (26 ± 11 mg/day). The high-nitrate diet supplied 5.5 mg nitrate/kg body weight, exceeding the Acceptable Daily Intake (ADI) of 3.7 mg nitrate/kg body weight. Supplementation with high-nitrate vegetables significantly increased plasma nitrate concentrations (baseline; 30 ± 20 µM, after high-nitrate vegetables; 129 ± 87 µM) and plasma nitrite concentrations (baseline; 119 ± 35 nM, after high-nitrate vegetables; 227 ± 89 nM) but did not significantly change systolic blood pressure or the physiological response to moderate exercise. There were significant correlations between diastolic blood pressure and plasma nitrite concentrations (low-nitrate diet; r = 0.63, high-nitrate diet, r = 0.56).&#x0D; Conclusion: Supplementation with high-nitrate vegetables above the ADI significantly increased plasma nitrate and nitrate concentrations but did not significantly reduce systolic blood pressure or the physiological response to moderate exercise. Plasma nitrite concentrations significantly correlated with diastolic blood pressure after high-nitrate and low-nitrate diets.

A Nitrate-Rich Vegetable Intervention Elevates Plasma Nitrate and Nitrite Concentrations and Reduces Blood Pressure in Healthy Young Adults

BackgroundEmerging evidence suggests that increasing dietary nitrate intake may be an effective approach to reduce blood pressure. Beetroot juice is often used to supplement dietary nitrate, whereas nitrate intake levels from habitual diet are low. An increase in the habitual intake of nitrate-rich vegetables may represent an alternative to nitrate supplementation. However, the effectiveness and acceptability of a nitrate–rich-vegetables diet remain to be established. ObjectiveThe aim was to investigate the effect and feasibility of two different intervention strategies to increase dietary nitrate intake, on plasma nitrate/nitrite concentrations and blood pressure. DesignA randomized, crossover trial was used. ParticipantsParticipants were healthy men and women (both n=15; age: 24±6 years) from the Netherlands. InterventionParticipants were instructed to consume ∼400 mg nitrate at lunch, provided through nitrate-rich vegetables and dietary counseling, or beetroot juice supplementation. Both interventions lasted 1 week, with 1-week washout (January to April 2017). Main outcomePlasma nitrate and nitrite concentrations and resting systolic and diastolic blood pressure were measured in an overnight fasted state (before and after intervention) and ∼2.5 hours after lunch (before and throughout intervention on day 1, 4, and 7). Statistical analysisTwo-factor (time × treatment) repeated-measures analyses of variance were performed. ResultsMean plasma nitrate concentrations increased with both interventions, with a larger increase in beetroot juice vs nitrate-rich vegetables, both in a fasted state and ∼2.5 hours after lunch (day 1, beetroot juice: 2.31±0.56 mg/dL [373±90 μmol/L] vs nitrate-rich vegetables: 1.71±0.83 mg/dL [277±134 μmol/L]; P<0.001). Likewise, mean plasma nitrite concentrations increased with both interventions, but were higher after lunch in beetroot juice than in nitrate-rich vegetables (day 1: 2.58±1.52 μg/dL [560±331 nmol/L] vs 2.15±1.21 μg/dL [468±263 nmol/L]; P=0.020). Fasting mean systolic and diastolic blood pressure did not change, but mean systolic and diastolic blood pressure assessed ∼2.5 hours after lunch were significantly reduced throughout both intervention periods (P<0.05), with no differences between beetroot juice and nitrate-rich vegetables (day 1, systolic blood pressure: –5.1±9.5 mm Hg and diastolic blood pressure: –5.3±8.9 mm Hg). ConclusionShort-term consumption of dietary nitrate in the form of nitrate-rich vegetables represents an effective means to increase plasma nitrate and nitrite concentrations, and reduces blood pressure to the same extent as beetroot juice supplementation.

Study of thermo-regulation as a worsening marker of experimental sepsis in an animal model.

Objective: to analyze variations in body temperature and in plasma nitrate and lactate concentrations in rats submitted to the experimental sepsis model.Method: a total of 40 rats divided equally into five groups. The induction of endotoxemia was performed with intravenous administration of lipopolysaccharide, 0.5 mg/Kg, 1.5 mg/Kg, 3.0 mg/Kg, and 10 mg/Kg, respectively. The control group received 0.5 mL of saline solution. The experiment lasted six hours, with evaluations performed at 0 (baseline data), 2nd, 4th, and 6thhours.Results: The animals that received doses up to 3.0 mg/kg showed a significant increase in body temperature compared to the group with 10 mg/kg, which showed a decrease in these values. The increase in plasma nitrate and lactate concentrations in the groups with lipopolysaccharide was significantly higher than in the group that received the saline solution and was correlated with the increase in body temperature.Conclusion: the variations in body temperature observed in this study showed the dose-dependent effect of lipopolysaccharide and were correlated with the increase in the concentrations of nitrate and plasma lactate biomarkers. The implications of this study are the importance of monitoring body temperature, together with the assessment of these pathophysiological markers, which suggest worsening in the prognosis of sepsis.

A randomized pilot study of nitrate supplementation with beetroot juice in acute respiratory failure

Nitrate rich beetroot juice (BRJ) can enhance nitric oxide signaling, leading to improved physical function in healthy and diseased populations, but its safety and biologic efficacy have not been evaluated in a critically ill population. We randomized 22 previously functional acute respiratory failure patients to either BRJ or placebo daily until day 14 or discharge. We measured blood nitrate and nitrite levels and quantified strength and physical function at intensive care unit (ICU) and hospital discharge. Participants were predominantly male (54%), aged 68.5 years with an APACHE III score of 62. BRJ increased plasma nitrate (mean 219.2 μM increase, p = 0.002) and nitrite levels (mean 0.144 μM increase, p = 0.02). We identified no adverse events. The unadjusted and adjusted effect sizes of the intervention on the short physical performance battery were small (d = 0.12 and d = 0.17, respectively). In this pilot trial, administration of BRJ was feasible and safe, increased blood nitrate and nitrate levels, but had a small effect on physical function. Future studies could evaluate the clinical efficacy of BRJ as a therapy to improve physical function in survivors of critical illness.

Effects of dietary nitrate supplementation on microvascular physiology at 4559 m altitude – A randomised controlled trial (Xtreme Alps)

Native highlanders (e.g. Sherpa) demonstrate remarkable hypoxic tolerance, possibly secondary to higher levels of circulating nitric oxide (NO) and increased microcirculatory blood flow. As part of the Xtreme Alps study (a randomised placebo-controlled trial of dietary nitrate supplementation under field conditions of hypobaric hypoxia), we investigated whether dietary supplementation with nitrate could improve NO availability and microvascular blood flow in lowlanders. Plasma measurements of nitrate, nitrite and nitroso species were performed together with measurements of sublingual (sidestream dark-field camera) and forearm blood flow (venous occlusion plethysmography) in 28 healthy adult volunteers resident at 4559 m for 1 week; half receiving a beetroot-based high-nitrate supplement and half receiving an identically-tasting low nitrate ‘placebo’. Dietary supplementation increased plasma nitrate concentrations 4-fold compared to the placebo group, both at sea level (SL; 19.2 vs 76.9 μM) and at day 5 (D5) of high altitude (22.9 vs 84.3 μM, p < 0.001). Dietary nitrate supplementation also significantly increased both plasma nitrite (0.78 vs. 0.86 μM SL, 0.31 vs. 0.41 μM D5, p = 0.03) and total nitroso product (11.3 vs. 19.7 nM SL, 9.7 vs. 12.3 nM D5, p < 0.001) levels both at sea level and at 4559 m. However, plasma nitrite concentrations were more than 50% lower at 4559 m compared to sea level in both treatment groups. Despite these significant changes, dietary nitrate supplementation had no effect on any measured read-outs of sublingual or forearm blood flow, even when environmental hypoxia was experimentally reversed using supplemental oxygen. In conclusion, dietary nitrate supplementation does not improve microcirculatory function at 4559 m.

Acute Supplementation with Nitrate-Rich Beetroot Juice Causes a Greater Increase in Plasma Nitrite and Reduction in Blood Pressure of Older Compared to Younger Adults

Nitrate-rich beetroot juice supplementation has been shown to improve cardiovascular and cognitive function in younger and older adults via increased nitric oxide production. However, it is unclear whether the level of effects differs between the two groups. We hypothesized that acute supplementation with nitrate-rich beetroot juice would improve cardiovascular and cognitive function in older and younger adults, with the potential for greater improvements in older adults. Thirteen younger (18–30 years) and 11 older (50–70 years) adults consumed either 150 mL of nitrate-rich beetroot juice (BR; 10.5 mmol nitrate) or placebo (PL; 1 mmol nitrate) in a double-blind, crossover design, 2.25 h prior to a 30-min treadmill walk. Plasma nitrate and nitrite concentrations, blood pressure (BP), heart rate (HR), cognitive function, mood and perceptual tests were performed throughout the trial. BR consumption significantly increased plasma nitrate (p < 0.001) and nitrite (p = 0.003) concentrations and reduced systolic BP (p < 0.001) in both age groups and reduced diastolic BP (p = 0.013) in older adults. Older adults showed a greater elevation in plasma nitrite (p = 0.038) and a greater reduction in diastolic BP (p = 0.005) following BR consumption than younger adults. Reaction time was improved in the Stroop test following BR supplementation for both groups (p = 0.045). Acute BR supplementation increased plasma nitrite concentrations and reduced diastolic BP to a greater degree in older adults; whilst systolic BP was reduced in both older and younger adults, suggesting nitrate-rich BR may improve cardiovascular health, particularly in older adults due to the greater benefits from reductions in diastolic BP.

Impact of eNOS 27-bp VNTR (4b/a) gene polymorphism with the risk of Systemic Lupus Erythematosus in south Indian subjects

ObjectiveEndothelial nitric oxide synthase (eNOS) is constitutively expressed by vascular endothelium including glomerular endothelium. Functional polymorphisms, -786T>C (rs2070744) promoter variant, 27 bp VNTR (4b/a) in intron 4 and 894G>T (rs1799983) exon variant of eNOS are known to alter the eNOS expression and activity leading to altered NO levels and contribute to the development of vascular and renal disease risk. Thus it might have a role in SLE risk and development of glomerulonephritis. Hence, the present study is aimed to investigate the role of eNOS polymorphisms in South Indian SLE patients. MethodsFive hundred and four subjects (219 SLE cases and 285 controls) were included in the present case-control study. Genotyping was done using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for -786T>C and 894G>T SNPs. Another, 4a4b variable number of tandem repeat polymorphism was genotyped using direct PCR method using primer pairs flanking the 27 bp direct repeat region in intron 4 of eNOS gene. ResultsOur analysis revealed that intron 4 27 bp VNTR genotype frequency differ significantly between the SLE patients and controls (OR: 1.73, 95% CI %:1.18–2.54, P = 0.004). Further, “a allele” frequency was significantly higher in SLE patients as compared to the controls (20 vs. 13.8%) (OR: 1.56, 95%CI: 1.11–2.18, P = 0.01). However, promoter polymorphism −786T>C and missense variant 894G>T were not significantly different between the SLE cases and controls (OR: 0.92, 95%CI: 0.64–1.33, P = 0.7 and OR: 1.4, 95%CI: 0.95–2.06, P = 0.095 respectively). Furthermore, no association was found between any of the three polymorphisms with lupus nephritis phenotype. Increased plasma nitrate levels were observed in SLE patients (36.79 ± 2.83 μM/L) as compared to healthy controls (28.53 ± 1.94 μM/L) (P = 0.01). In addition, the genotype-based simulations have indicated that combined effect of eNOS polymorphisms contribute to 30.5% variability in NO production. ConclusionResults of the present study indicate that 27-bp VNTR polymorphism in intron 4 of eNOS gene polymorphism may be the significant risk factor for SLE in south Indian subjects.

Inorganic Nitrate in Angina Study: A Randomized Double-Blind Placebo-Controlled Trial.

BackgroundIn this double‐blind randomized placebo‐controlled crossover trial, we investigated whether oral sodium nitrate, when added to existing background medication, reduces exertional ischemia in patients with angina.Methods and ResultsSeventy patients with stable angina, positive electrocardiogram treadmill test, and either angiographic or functional test evidence of significant ischemic heart disease were randomized to receive oral treatment with either placebo or sodium nitrate (600 mg; 7 mmol) for 7 to 10 days, followed by a 2‐week washout period before crossing over to the other treatment (n=34 placebo‐nitrate, n=36 nitrate‐placebo). At baseline and at the end of each treatment, patients underwent modified Bruce electrocardiogram treadmill test, modified Seattle Questionnaire, and subgroups were investigated with dobutamine stress, echocardiogram, and blood tests. The primary outcome was time to 1 mm ST depression on electrocardiogram treadmill test. Compared with placebo, inorganic nitrate treatment tended to increase the primary outcome exercise time to 1 mm ST segment depression (645.6 [603.1, 688.0] seconds versus 661.2 [6183, 704.0] seconds, P=0.10) and significantly increased total exercise time (744.4 [702.4, 786.4] seconds versus 760.9 [719.5, 802.2] seconds, P=0.04; mean [95% confidence interval]). Nitrate treatment robustly increased plasma nitrate (18.3 [15.2, 21.5] versus 297.6 [218.4, 376.8] μmol/L, P<0.0001) and almost doubled circulating nitrite concentrations (346 [285, 405] versus 552 [398, 706] nmol/L, P=0.003; placebo versus nitrate treatment). Other secondary outcomes were not significantly altered by the intervention. Patients on antacid medication appeared to benefit less from nitrate supplementation.ConclusionsSodium nitrate treatment may confer a modest exercise capacity benefit in patients with chronic angina who are taking other background medication.Clinical Trial Registration URL: https://www.clinicaltrials.gov/. Unique identifier: NCT02078921. EudraCT number: 2012‐000196‐17.

Natural sports supplement formulation for physical endurance: a randomized, double-blind, placebo-controlled study

Natural ingredients have great demand to formulate the health supplements to enhance the physical endurance and stamina of any active persons. Fitnox™ is a natural ingredient formulation which contains the extracts of Kaempferia parviflora root, Punica granatum peel and Moringa oleifera leaves. The study was designed to investigate the efficacy of Fitnox™ for physical endurance in healthy male adults before and after exercise for a period of 22 days. Twenty four healthy male participants consumed 250 mg of either Fitnox™ or placebo (1:1 ratio) daily and they visited the clinic on day 0 and day 22 for physical examination. Serum chemistry, hematology and the levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), heart rate, red blood cell (RBC) count, dopamine, nitrate and nitrite were analyzed before and after exercise on screening and final visit. There was a 31% increase in plasma nitrate before exercise and 45% after exercise for the test groups on day 22. Similarly, the nitrite content increased 49% and 47% for pre- and post-exercises, respectively, in plasma. In saliva, the concentrations of the nitrate increased 24% and 18% before and after exercise, respectively. The saliva nitrite also increased 18% and 11% in pre- and post-exercise. Moreover, the dopamine concentration is considerably increased (36%) after the administration of the Fitnox™ (P < 0.05). Serum inflammatory biomarker LDH decreased from 635 to 582 U/L (P < 0.05) in post-exercise and MDA decreased 47% in the Fitnox™ group (P < 0.01), but no considerable change in the placebo group. It was concluded from the study that Fitnox™ not only increases the performance but it also reduces the oxidative stress to the muscles and tissues during exercise. There were no study-related adverse events reported between both the treatment groups and the results indicated that the Fitnox™ which enhances the physical endurance considerably.

Differential vascular reactivity responses acutely following ingestion of a nitrate rich red spinach extract.

Inorganic nitrate ingestion has been posited to affect arterial blood pressure and vascular function. We sought to determine the acute effect of a red spinach extract (RSE) high in inorganic nitrate on vascular reactivity 1-h after ingestion in peripheral conduit and resistance arteries. Fifteen (n=15; males 8, females 7) apparently healthy subjects (aged 23.1±3.3years; BMI 27.2±3.7kg/m2) participated in this crossover design, double-blinded study. Subjects reported to the lab ≥2-h post-prandial and consumed RSE (1000mg dose; ~90mg nitrate) or placebo (PBO). Venipuncture was performed on three occasions: baseline, 30-min post-ingestion and between 65 to 75-min post-ingestion. Baseline vascular measurements [i.e., calf venous occlusion plethysmography, brachial artery flow-mediated dilation (FMD)], 30-min of continuous blood pressure (BP) and heart rate (HR) analysis, and follow-up vascular measurements beginning at 40-min post-ingestion were also performed. Humoral nitrate following RSE ingestion was significantly higher at 30- (+54%; P=0.039) and 65 to 75-min post-ingestion compared to baseline (+255%, P<0.001) and PBO at the same time points (P<0.05). No significant changes in BP or HR occurred in either condition. Peak reactive hyperemia (RH) calf blood flow increased significantly (+13.7%; P=0.016) following RSE ingestion, whereas it decreased (-14.0%; P=0.008) following PBO ingestion. No significant differential FMD responses were detected (P>0.05), though RH was decreased following the baseline measure in both conditions. RSE significantly increased plasma nitrate 30-min post-ingestion, but acute microvascular (i.e., resistance vasculature) reactivity increases were isolated to the lower limb and no appreciable change in brachial artery FMD was observed.

Editorial: New Translational Insights on Metabolic Syndrome: Obesity, Hypertension, Diabetes and Beyond.

Editorial: New Translational Insights on Metabolic Syndrome: Obesity, Hypertension, Diabetes and Beyond.