Effects of dietary nitrate supplementation, from beetroot juice, on blood pressure in hypertensive pregnant women: A randomised, double-blind, placebo-controlled feasibility trial

The Effect of Dietary Nitrate on the Oral Microbiome and Salivary Biomarkers in Individuals with High Blood Pressure

BACKGROUND

Green leafy vegetables (GLV) contain inorganic nitrate, an anion with potential prebiotic effects on the oral microbiome. However, it remains unclear whether GLV and pharmacological supplementation [potassium nitrate (PN)] with a nitrate salt induce similar effects on the oral microbiome.

OBJECTIVES

This study aimed to compare the effect of GLV with PN supplementation on the oral microbiome composition and salivary biomarkers in individuals with high blood pressure.

METHODS

Seventy individuals were randomly allocated to 3 different groups to follow a 5-wk dietary intervention. Group 1 consumed 300 mg/d of nitrate in form of GLV. Group 2 consumed pills with 300 mg/d of PN and low-nitrate vegetables. Group 3 consumed pills with potassium chloride (placebo: PLAC) and low-nitrate vegetables. The oral microbiome composition and salivary biomarkers of oral health were analyzed before and after the dietary intervention.

RESULTS

The GLV and PN groups showed similar microbial changes, probably nitrate-dependent, including an increase in the abundance of Neisseria, Capnocytophaga, Campylobacter species, and a decrease in Veillonella, Megasphaera, Actinomyces, and Eubacterium species after the treatment. Increased abundance of Rothia species, and reduced abundance of Streptococcus, Prevotella, Actinomyces, and Mogibacterium species were observed in the GLV group, which could be nitrate-independent. GLV and PN treatments increased salivary pH, but only GLV treatment showed an increase in the salivary buffering capacity and a reduction of lactate.

CONCLUSION

The combination of nitrate-dependent and nitrate-independent microbial changes in the GLV group has a stronger effect to potentially improve oral health biomarkers compared with PN.

The Nitrate-Nitrite-Nitric Oxide Pathway: Potential Role in Mitigating Oxidative Stress in Hypertensive Disorders of Pregnancy

Hypertensive diseases of pregnancy (HDPs) represent a global clinical challenge, affecting 5-10% of women and leading to complications for both maternal well-being and fetal development. At the heart of these complications is endothelial dysfunction, with oxidative stress emerging as a pivotal causative factor. The reduction in nitric oxide (NO) bioavailability is a vital indicator of this dysfunction, culminating in blood pressure dysregulation. In the therapeutic context, although antihypertensive medications are commonly used, they come with inherent concerns related to maternal-fetal safety, and a percentage of women do not respond to these therapies. Therefore, alternative strategies that directly address the pathophysiology of HDPs are required. This article focuses on the potential of the nitrate-nitrite-NO pathway, abundantly present in dark leafy greens and beetroot, as an alternative approach to treating HDPs. The objective of this review is to discuss the prospective antioxidant role of nitrate. We hope our discussion paves the way for using nitrate to improve endothelial dysfunction and control oxidative stress, offering a potential therapy for managing HDPs.

Investigating the association between nitrate dosing and nitrite generation by the human oral microbiota in continuous culture

The generation of nitrite by the oral microbiota is believed to contribute to healthy cardiovascular function, with oral nitrate reduction to nitrite associated with systemic blood pressure regulation. There is the potential to manipulate the composition or activities of the oral microbiota to a higher nitrate-reducing state through nitrate supplementation. The current study examined microbial community composition and enzymatic responses to nitrate supplementation in sessile oral microbiota grown in continuous culture. Nitrate reductase (NaR) activity and nitrite concentrations were not significantly different to tongue-derived inocula in model biofilms. These were generally dominated by Streptococcus spp., initially, and a single nitrate supplementation resulted in the increased relative abundance of the nitrate-reducing genera Veillonella, Neisseria, and Proteus spp. Nitrite concentrations increased concomitantly and continued to increase throughout oral microbiota development. Continuous nitrate supplementation, over a 7-day period, was similarly associated with an elevated abundance of nitrate-reducing taxa and increased nitrite concentration in the perfusate. In experiments in which the models were established in continuous low or high nitrate environments, there was an initial elevation in nitrate reductase, and nitrite concentrations reached a relatively constant concentration over time similar to the acute nitrate challenge with a similar expansion of Veillonella and Neisseria. In summary, we have investigated nitrate metabolism in continuous culture oral biofilms, showing that nitrate addition increases nitrate reductase activity and nitrite concentrations in oral microbiota with the expansion of putatively NaR-producing taxa.IMPORTANCEClinical evidence suggests that blood pressure regulation can be promoted by nitrite generated through the reduction of supplemental dietary nitrate by the oral microbiota. We have utilized oral microbiota models to investigate the mechanisms responsible, demonstrating that nitrate addition increases nitrate reductase activity and nitrite concentrations in oral microbiota with the expansion of nitrate-reducing taxa.

Beetroot juice, exercise, and cardiovascular function in women planning to conceive

OBJECTIVE

Prepregnancy optimization of cardiovascular function may reduce the risk of pre-eclampsia. We aimed to assess the feasibility and effect of preconception cardiovascular monitoring, exercise, and beetroot juice on cardiovascular parameters in women planning to conceive.

DESIGN AND METHOD

Prospective single-site, open-label, randomized controlled trial. Thirty-two women, aged 18-45 years, were allocated into one of four arms (1 : 1 : 1 : 1): exercise, beetroot juice, exercise plus beetroot juice and no intervention for 12 weeks. Blood pressure (BP) was measured at home daily. Cardiac output ( CO ) and total peripheral resistance (TPR) were assessed via bio-impedance.

RESULTS

Twenty-nine out of 32 (91%) participants completed the study. Adherence to daily BP and weight measurements were 81% and 78%, respectively ( n  = 29). Eight out of 15 (53%) of participants did not drink all the provided beetroot juice because of forgetfulness and taste. After 12 weeks, exercise was associated with a reduction in standing TPR (-278 ± 0.272 dynes s cm -5 , P  < 0.05), and an increase in standing CO (+0.88 ± 0.71 l/min, P  < 0.05). Exercise and beetroot juice together was associated with a reduction in standing DBP ( 7 ± 6 mmHg, P  < 0.05), and an increase in standing CO (+0.49 ± 0.66 l/min, P  < 0.05). The control group showed a reduction in standing TPR ( 313 ± 387 dynes s cm -5 ) and standing DBP ( 8 ± 5mmHg). All groups gained weight.

CONCLUSION

Exercise and beetroot juice in combination showed a signal towards improving cardiovascular parameters. The control group showed improvements, indicating that home measurement devices and regular recording of parameters are interventions in themselves. Nevertheless, interventions before pregnancy to improve cardiovascular parameters may alter the occurrence of hypertensive conditions during pregnancy and require further investigation in adequately powered studies.

Should the non-canonical pathway of nitric oxide generation be targeted in hypertensive pregnancies?

Hypertension in pregnancy is prevalent, affecting around 10% of pregnancies worldwide, and significantly increases the risk of adverse outcomes for both mothers and their babies. Current treatment strategies for pregnant women with hypertension are limited, and new approaches for the management of hypertension in pregnancy are urgently needed. Substantial evidence from non-pregnant subjects has demonstrated the potential for dietary nitrate supplementation to increase nitric oxide (NO) bioavailability and lower blood pressure, following bioactivation via the non-canonical NO pathway. Emerging data suggest this approach may also be of benefit in pregnant women, although studies are limited. This review aims to summarise the current evidence from preclinical and clinical studies of nitrate supplementation in pregnancy, drawing on data from non-pregnant populations where appropriate and highlighting key gaps in knowledge that remain to be addressed in future trials.

Altered Oral Nitrate Reduction and Bacterial Profiles in Hypertensive Women Predict Blood Pressure Lowering Following Acute Dietary Nitrate Supplementation

BACKGROUND

The efficacy of dietary nitrate supplementation to lower blood pressure (BP) in pregnant women is highly variable. We aimed to investigate whether differences in oral microbiota profiles and oral nitrate-reducing capacity may explain interindividual differences in BP lowering following nitrate supplementation.

METHODS

Participants recruited for this study were both pregnant and nonpregnant women, with or without hypertension (n=55). Following an overnight fast, plasma, saliva, and tongue scraping samples were collected for measurement of nitrate/nitrite concentrations, oral NaR (nitrate reductase) activity, and microbiota profiling using 16S rRNA gene sequencing. Baseline BP was measured, followed by the administration of a single dose of dietary nitrate (400 mg nitrate in 70 mL beetroot juice). Post-nitrate intervention, plasma and salivary nitrate/nitrite concentrations and BP were determined 2.5 hours later.

RESULTS

Women with hypertension had significantly lower salivary nitrite concentrations (P=0.006) and reduced abundance of the nitrate-reducing taxa Veillonella(P=0.007) compared with normotensive women. Oral NaR activity was not significantly different in pregnant versus nonpregnant women (P=0.991) but tended to be lower in hypertensive compared with normotensive women (P=0.099). Oral NaR activity was associated with both baseline diastolic BP (P=0.050) and change in diastolic BP following acute nitrate intake (P=0.01, adjusted for baseline BP).

CONCLUSIONS

The abundance and activity of oral nitrate-reducing bacteria impact both baseline BP as well as the ability of dietary nitrate supplementation to lower BP. Strategies to increase oral nitrate-reducing capacity could lower BP and enhance the efficacy of dietary nitrate supplementation, in pregnancy as well as in nonpregnant adults.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT03930693.

Supplementation with l-arginine and nitrates vs age and individual physiological reactivity

Ageing is a natural ontogenetic phenomenon that entails a decrease in the adaptive capacity of the organism, as a result of which the body becomes less adaptable to stressful conditions. Nitrate and nitrite enter the body from exogenous sources and from nitrification of ammonia nitrogen by intestinal microorganisms. This review considers the mechanisms of action of l-arginine, a known inducer of nitric oxide (NO) biosynthesis, and nitrates as supplements in the processes of ageing and aggravated stress states, in which mechanisms of individual physiological reactivity play an important role. This approach can be used as an element of individual therapy or prevention of premature ageing processes depending on the different levels of initial reactivity of the functional systems. A search was performed of the PubMed, Scopus, and Google Scholar databases (n = 181 articles) and the author's own research (n = 4) up to May 5, 2023. The review presents analyses of data on targeted treatment of NO generation by supplementation with l-arginine or nitrates, which is a promising means for prevention of hypoxic conditions frequently accompanying pathological processes in an ageing organism. The review clarifies the role of the individual state of physiological reactivity, using the example of individuals with a high predominance of cholinergic regulatory mechanisms who already have a significant reserve of adaptive capacity. In studies of the predominance of adrenergic influences, a poorly trained organism as well as an elderly organism correspond to low resistance, which is an additional factor of damage at increased energy expenditure. Conclusion: It is suggested that the role of NO synthesis from supplementation of dietary nitrates and nitrites increases with age rather than from oxygen-dependent biosynthetic reactions from l-arginine supplementation.

From nitrate to NO: potential effects of nitrate-reducing bacteria on systemic health and disease

Current research has described improving multisystem disease and organ function through dietary nitrate (DN) supplementation. They have provided some evidence that these floras with nitrate (NO3-) reductase are mediators of the underlying mechanism. Symbiotic bacteria with nitrate reductase activity (NRA) are found in the human digestive tract, including the mouth, esophagus and gastrointestinal tract (GT). Nitrate in food can be converted to nitrite under the tongue or in the stomach by these symbiotic bacteria. Then, nitrite is transformed to nitric oxide (NO) by non-enzymatic synthesis. NO is currently recognized as a potent bioactive agent with biological activities, such as vasodilation, regulation of cardiomyocyte function, neurotransmission, suppression of platelet agglutination, and prevention of vascular smooth muscle cell proliferation. NO also can be produced through the conventional L-arginine-NO synthase (L-NOS) pathway, whereas endogenous NO production by L-arginine is inhibited under hypoxia-ischemia or disease conditions. In contrast, exogenous NO3-/NO2-/NO activity is enhanced and becomes a practical supplemental pathway for NO in the body, playing an essential role in various physiological activities. Moreover, many diseases (such as metabolic or geriatric diseases) are primarily associated with disorders of endogenous NO synthesis, and NO generation from the exogenous NO3-/NO2-/NO route can partially alleviate the disease progression. The imbalance of NO in the body may be one of the potential mechanisms of disease development. Therefore, the impact of these floras with nitrate reductase on host systemic health through exogenous NO3-/NO2-/NO pathway production of NO or direct regulation of floras ecological balance is essential (e.g., regulation of body homeostasis, amelioration of diseases, etc.). This review summarizes the bacteria with nitrate reductase in humans, emphasizing the relationship between the metabolic processes of this microflora and host systemic health and disease. The potential effects of nitrate reduction bacteria on human health and disease were also highlighted in disease models from different human systems, including digestive, cardiovascular, endocrine, nervous, respiratory, and urinary systems, providing innovative ideas for future disease diagnosis and treatment based on nitrate reduction bacteria.

Sodium Nitrite Attenuates Reduced Activity of Vascular Matrix Metalloproteinase-2 and Vascular Hyper-Reactivity and Increased Systolic Blood Pressure Induced by the Placental Ischemia Model of Preeclampsia in Anesthetized Rats

Preeclampsia is a maternal hypertension disorder associated with vascular dysfunction and fetal and placental growth restrictions. Placental ischemia is suggested as the primary trigger of preeclampsia-associated impairments of both endothelium-derived nitric oxide (NO) and the vascular activity of extracellular matrix metalloproteinase-2 (MMP-2). Reduced uteroplacental perfusion pressure (RUPP) is a placental ischemia model of preeclampsia. Reduction of sodium nitrite to NO may occur during ischemic conditions. However, sodium nitrite effects in the RUPP model of preeclampsia have not yet been investigated. Pregnant rats were divided into four groups: normotensive pregnant rats (Norm-Preg), pregnant rats treated with sodium nitrite (Preg + Nitrite), preeclamptic rats (RUPP), and preeclamptic rats treated with sodium nitrite (RUPP + Nitrite). Maternal blood pressure and fetal and placental parameters were recorded. Vascular function, circulating NO metabolites, and the gelatinolytic activity of vascular MMP-2 were also examined. Sodium nitrite attenuates increased blood pressure, prevents fetal and placental weight loss, counteracts vascular hyper-reactivity, and partially restores NO metabolites and MMP-2 activity. In conclusion, sodium nitrite reduction to NO may occur during RUPP-induced placental ischemia, thereby attenuating increased blood pressure, fetal and placental growth restriction, and vascular hyper-reactivity associated with preeclampsia and possibly restoring NO and MMP-2 activity, which underlie the blood pressure-lowering effects.

Acute beetroot juice reduces blood pressure in young Black and White males but not females

A complex interplay of social, lifestyle, and physiological factors contribute to Black Americans having the highest blood pressure (BP) in America. One potential contributor to Black adult's higher BP may be reduced nitric oxide (NO) bioavailability. Therefore, we sought to determine whether augmenting NO bioavailability with acute beetroot juice (BRJ) supplementation would reduce resting BP and cardiovascular reactivity in Black and White adults, but to a greater extent in Black adults. A total of 18 Black and 20 White (∼equal split by biological sex) young adults completed this randomized, placebo-controlled (nitrate (NO3-)-depleted BRJ), crossover design study. We measured heart rate, brachial and central BP, and arterial stiffness (via pulse wave velocity) at rest, during handgrip exercise, and during post-exercise circulatory occlusion. Compared with White adults, Black adults exhibited higher pre-supplementation resting brachial and central BP (Ps ≤0.035; e.g., brachial systolic BP: 116(11) vs. 121(7) mmHg, P = 0.023). Compared with placebo, BRJ (∼12.8 mmol NO3-) reduced resting brachial systolic BP similarly in Black (Δ-4±10 mmHg) and White (Δ-4±7 mmHg) adults (P = 0.029). However, BRJ supplementation reduced BP in males (Ps ≤ 0.020) but not females (Ps ≥ 0.299). Irrespective of race or sex, increases in plasma NO3- were associated with reduced brachial systolic BP (ρ = -0.237, P = 0.042). No other treatment effects were observed for BP or arterial stiffness at rest or during physical stress (i.e., reactivity); Ps ≥ 0.075. Despite young Black adults having higher resting BP, acute BRJ supplementation reduced systolic BP in young Black and White adults by a similar magnitude, an effect that was driven by males.

Hypertensive disorders of pregnancy

Hypertensive disorders of pregnancy (HDP) are one of the most commonly occurring complications of pregnancy and include chronic hypertension, gestational hypertension, and pre-eclampsia. New developments in early pregnancy screening to identify women at high risk for pre-eclampsia combined with targeted aspirin prophylaxis could greatly reduce the number of affected pregnancies. Furthermore, recent advances in the diagnosis of pre-eclampsia, such as placental growth factor based testing, have been shown to improve the identification of those pregnancies at highest risk of severe complications. Evidence from trials has refined the target blood pressure and timing of delivery to manage chronic hypertension and pre-eclampsia with non-severe features, respectively. Importantly, a wealth of epidemiological data now links HDP to future cardiovascular disease and diabetes decades after an affected pregnancy. This review discusses the current guidelines and research data on the prevention, diagnosis, management, and postnatal follow-up of HDP. It also discusses the gap in knowledge regarding the long term risks for cardiovascular disease following HDP and illustrates the importance of improving adherence to postnatal guidelines to monitor hypertension and the need for more research focused on primary prevention of future cardiovascular disease in women identified as being at high risk because of HDP.

Common pregnancy complications and polyphenols intake: an overview

During pregnancy, the body undergoes a great amount of changes in order to support a healthy developing fetus. In this context, maternal dietary supplementation is widely encouraged to provide adequate nutrition for the newborn. In the past few years, studies have emerged highlighting the benefits of polyphenols intake during pregnancy. Indeed, despite differences among reports, such as experimental model, polyphenol employed, dosage and regimen of administration, there is no doubt that the ingestion of these molecules has a protective effect in relation to three pregnancy-associated diseases or conditions: preeclampsia, gestational diabetes and fetal growth restriction. In this review, we describe the effects of different polyphenols and polyphenol-rich extracts or juices on the main outcomes of these common pregnancy-associated complications, obtained in human, animal and in vitro studies. Therefore, this work provides a critical analysis of the literature, and a summary of evidences, from which future research using polyphenols can be designed and evaluated.

The Generation of Nitric Oxide from Aldehyde Dehydrogenase-2: The Role of Dietary Nitrates and Their Implication in Cardiovascular Disease Management

Reduced bioavailability of the nitric oxide (NO) signaling molecule has been associated with the onset of cardiovascular disease. One of the better-known and effective therapies for cardiovascular disorders is the use of organic nitrates, such as glyceryl trinitrate (GTN), which increases the concentration of NO. Unfortunately, chronic use of this therapy can induce a phenomenon known as "nitrate tolerance", which is defined as the loss of hemodynamic effects and a reduction in therapeutic effects. As such, a higher dosage of GTN is required in order to achieve the same vasodilatory and antiplatelet effects. Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is a cardioprotective enzyme that catalyzes the bio-activation of GTN to NO. Nitrate tolerance is accompanied by an increase in oxidative stress, endothelial dysfunction, and sympathetic activation, as well as a loss of the catalytic activity of ALDH2 itself. On the basis of current knowledge, nitrate intake in the diet would guarantee a concentration of NO such as to avoid (or at least reduce) treatment with GTN and the consequent onset of nitrate tolerance in the course of cardiovascular diseases, so as not to make necessary the increase in GTN concentrations and the possible inhibition/alteration of ALDH2, which aggravates the problem of a positive feedback mechanism. Therefore, the purpose of this review is to summarize data relating to the introduction into the diet of some natural products that could assist pharmacological therapy in order to provide the NO necessary to reduce the intake of GTN and the phenomenon of nitrate tolerance and to ensure the correct catalytic activity of ALDH2.

Systematic evaluation of the pre-eclampsia drugs, dietary supplements and biologicals pipeline using target product profiles

BACKGROUND

The Accelerating Innovation for Mothers (AIM) project established a database of candidate medicines in research and development (R&amp;D) between 2000 and 2021 for five pregnancy-related conditions, including pre-eclampsia. In parallel, we published target product profiles (TPPs) that describe optimal characteristics of medicines for use in preventing/treating pre-eclampsia. The study objective was to use systematic double screening and extraction to identify all candidate medicines being investigated for pre-eclampsia prevention/treatment and rank their potential based on the TPPs.

METHODS

Adis Insight, Pharmaprojects, WHO international clinical trials registry platform (ICTRP), PubMed and grant databases were searched (Jan-May 2021). The AIM database was screened for all candidates being investigated for pre-eclampsia. Candidates in clinical development were evaluated against nine prespecified criteria from TPPs identified as key for wide-scale implementation, and classified as high, medium or low potential based on matching to the TPPs. Preclinical candidates were categorised by product type, archetype and medicine subclass.

RESULTS

The AIM database identified 153 candidates for pre-eclampsia. Of the 87 candidates in clinical development, seven were classified as high potential (prevention: esomeprazole, L-arginine, chloroquine, vitamin D and metformin; treatment: sulfasalazine and metformin) and eight as medium potential (prevention: probiotic lactobacilli, dalteparin, selenium and omega-3 fatty acid; treatment: sulforaphane, pravastatin, rosuvastatin and vitamin B3). Sixty-six candidates were in preclinical development, the most common being amino acid/peptides, siRNA-based medicines and polyphenols.

CONCLUSIONS

This is a novel, evidence-informed approach to identifying promising candidates for pre-eclampsia prevention and treatment - a vital step in stimulating R&amp;D of new medicines for pre-eclampsia suitable for real-world implementation.

Efficacy and Variability in Plasma Nitrite Levels during Long-Term Supplementation with Nitrate Containing Beetroot Juice

Long-term consumption of beetroot juice on efficacy of converting dietary nitrate to plasma nitrate and nitrite was investigated. Adults were randomized to consume either beetroot juice with 380 mg of nitrate (BR) or a beetroot juice placebo (PL) for 12-weeks. Plasma nitrate and nitrite were measured before and 90-minutes after consuming their intervention beverage. Percent change in nitrite across the 90 min was greater in BR (273.2 ± 39.9%) vs. PL (4.9 ± 36.9%). Long-term consumption of nitrate containing beetroot juice increased fasting nitrate and nitrite plasma levels compared to baseline.

A comprehensive review of beetroot (Beta vulgaris L.) bioactive components in the food and pharmaceutical industries

Beetroot is rich in various bioactive phytochemicals, which are beneficial for human health and exert protective effects against several disease conditions like cancer, atherosclerosis, etc. Beetroot has various therapeutic applications, including antioxidant, antibacterial, antiviral, and analgesic functions. Besides the pharmacological effects, food industries are trying to preserve beetroots or their phytochemicals using various food preservation methods, including drying and freezing, to preserve their antioxidant capacity. Beetroot is a functional food due to valuable active components such as minerals, amino acids, phenolic acid, flavonoid, betaxanthin, and betacyanin. Due to its stability, nontoxic and non-carcinogenic and nonpoisonous capabilities, beetroot has been used as an additive or preservative in food processing. Beetroot and its bioactive compounds are well reported to possess antioxidant, anti-inflammatory, antiapoptotic, antimicrobial, antiviral, etc. In this review, we provided updated details on (i) food processing, preservation and colorant methods using beetroot and its phytochemicals, (ii) synthesis and development of several nanoparticles using beetroot and its bioactive compounds against various diseases, (iii) the role of beetroot and its phytochemicals under disease conditions with molecular mechanisms. We have also discussed the role of other phytochemicals in beetroot and their health benefits. Recent technologies in food processing are also updated. We also addressed on molecular docking-assisted biological activity and screening for bioactive chemicals. Additionally, the role of betalain from different sources and its therapeutic effects have been listed. To the best of our knowledge, little or no work has been carried out on the impact of beetroot and its nanoformulation strategies for phytocompounds on antimicrobial, antiviral effects, etc. Moreover, epigenetic alterations caused by phytocompounds of beetroot under several diseases were not reported much. Thus, extensive research must be carried out to understand the molecular effects of beetroot in the near future.

Nitric oxide, aging and aerobic exercise: Sedentary individuals to Master's athletes

Aging is associated with a decline in physiological function and exercise performance. These effects are mediated, at least in part, by an age-related decrease in the bioavailability of nitric oxide (NO), a ubiquitous gasotransmitter and regulator of myriad physiological processes. The decrease in NO bioavailability with aging is especially apparent in sedentary individuals, whereas older, physically active individuals maintain higher levels of NO with advancing age. Strategies which enhance NO bioavailability (including nutritional supplementation) have been proposed as a potential means of reducing the age-related decrease in physiological function and enhancing exercise performance and may be of interest to a range of older individuals including those taking part in competitive sport. In this brief review we discuss the effects of aging on physiological function and endurance exercise performance, and the potential role of changes in NO bioavailability in these processes. We also provide a summary of current evidence for dietary supplementation with substrates for NO production - including inorganic nitrate and nitrite, l-arginine and l-citrulline - for improving exercise capacity/performance in older adults. Additionally, we discuss the (limited) evidence on the effects of (poly)phenols and other dietary antioxidants on NO bioavailability in older individuals. Finally, we provide suggestions for future research.

Combination of Oxalobacter Formigenes and Veillonella Parvula in Gastrointestinal Microbiota Related to Bile-Acid Metabolism as a Biomarker for Hypertensive Nephropathy

The human microbiome is a mixed group of microorganisms, which individually consists of 10–100 trillion symbiotic microbial cells. The relationship between gastrointestinal microbiota and blood pressure has been verified and the intestinal microbiota of chronic kidney disease (CKD) patients in the distribution of bacterial species is different from the flora of people with no CKD. The purpose of this research is to study the different intestinal microbiota of hypertensive patients with and without nephropathy and to find possible biomarkers of hypertensive nephropathy (H-CKD). The subjects of this research were divided into three groups, healthy control group, hypertension group, and hypertensive nephropathy group. Sequencing, bioinformatics, and statistical analysis were performed on the 16S rRNA gene of the subjects' stool samples. This research study showed the differences of intestinal flora as biomarkers in hypertension patients with and without nephropathy; it investigated the relationship of the differences in the intestinal microbiota with bile-acid metabolism; it also explored bile-acid metabolism mechanism of intestinal microbiota differences in hypertension with or without nephropathy. In summary, the difference in the combination of O. formigenes and V. parvula in the gastrointestinal microbiota is related to bile-acid metabolism in hypertensive patients and can be one of the factors causing CKD. It is the first time to report such a biomarker or pathogenic factor of H-CKD in the world.

The importance of nutrition in pregnancy and lactation: lifelong consequences

Most women in the United States do not meet the recommendations for healthful nutrition and weight before and during pregnancy. Women and providers often ask what a healthy diet for a pregnant woman should look like. The message should be “eat better, not more.” This can be achieved by basing diet on a variety of nutrient-dense, whole foods, including fruits, vegetables, legumes, whole grains, healthy fats with omega-3 fatty acids that include nuts and seeds, and fish, in place of poorer quality highly processed foods. Such a diet embodies nutritional density and is less likely to be accompanied by excessive energy intake than the standard American diet consisting of increased intakes of processed foods, fatty red meat, and sweetened foods and beverages. Women who report “prudent” or “health-conscious” eating patterns before and/or during pregnancy may have fewer pregnancy complications and adverse child health outcomes. Comprehensive nutritional supplementation (multiple micronutrients plus balanced protein energy) among women with inadequate nutrition has been associated with improved birth outcomes, including decreased rates of low birthweight. A diet that severely restricts any macronutrient class should be avoided, specifically the ketogenic diet that lacks carbohydrates, the Paleo diet because of dairy restriction, and any diet characterized by excess saturated fats. User-friendly tools to facilitate a quick evaluation of dietary patterns with clear guidance on how to address dietary inadequacies and embedded support from trained healthcare providers are urgently needed.

Recent evidence has shown that although excessive gestational weight gain predicts adverse perinatal outcomes among women with normal weight, the degree of prepregnancy obesity predicts adverse perinatal outcomes to a greater degree than gestational weight gain among women with obesity. Furthermore, low body mass index and insufficient gestational weight gain are associated with poor perinatal outcomes. Observational data have shown that first-trimester gain is the strongest predictor of adverse outcomes. Interventions beginning in early pregnancy or preconception are needed to prevent downstream complications for mothers and their children. For neonates, human milk provides personalized nutrition and is associated with short- and long-term health benefits for infants and mothers. Eating a healthy diet is a way for lactating mothers to support optimal health for themselves and their infants.

Reduced Abundance of Nitrate-Reducing Bacteria in the Oral Microbiota of Women with Future Preeclampsia

The oral microbiota can contribute to the regulation of blood pressure by increasing the availability of nitric oxide through the reduction of nitrate to nitrite, which can be converted into nitric oxide in the stomach and then enter the circulation. It is unclear if the composition of the oral microbiota is different between women who do and do not develop preeclampsia. This study aimed to compare the composition of the buccal microbiota just prior to the development of symptoms at 36 weeks gestation in 12 women who developed late-onset preeclampsia and 24 matched women who remained normotensive throughout pregnancy by 16S rRNA gene amplicon sequencing. The abundance of the nitrate-reducing Veillonella spp V. parvula and V. dispar and a subunit of nitrate reductase narH was compared using real-time PCR. The abundance of bacteria was correlated with maternal blood pressure and dietary intake of nitrate-containing vegetables. The results showed that the abundance of nitrate-reducing bacteria including Veillonella, specifically V. parvula, and Prevotella was reduced in women who developed preeclampsia. Veillonella but not Prevotella abundance was negatively correlated with maternal blood pressure. The dietary intake of nitrate-containing vegetables did not differ between the groups and was not correlated with the abundance of Veillonella. There was no difference in the abundance of the nitrate reductase subunit narH between the groups. These results suggest that the abundance of nitrate-reducing bacteria is reduced in the oral microbiota of women who later develop preeclampsia, indicating a potential pathway for prevention.

Beetroot as a functional food with huge health benefits: Antioxidant, antitumor, physical function, and chronic metabolomics activity

Previously, beetroot is mainly consumed as a food additive. In recent years, the beetroot, especially the betalains (betanin) and nitrates it contains, now has received increasing attention for their effective biological activity. Betalains have been proven to eliminate oxidative and nitrative stress by scavenging DPPH, preventing DNA damage, and reducing LDL. It also has been found to exert antitumor activity by inhibiting cell proliferation, angiogenesis, inducing cell apoptosis, and autophagy. In some chronic diseases, nitrate is the main component for lowing blood lipids, glucose, and pressure, while its role in treating hypertension and hyperglycemia has not been clearly stated. Moreover, the intake of nitrate-rich beetroot could enhance athletic performance and attenuate muscle soreness in certain types of exercise. The objective of this review is to provide sufficient evidence for the clarification of health benefits of beetroot, especially in the aspect of biooxidation, neoplastic diseases, some chronic diseases, and energy supplementation.

Nitric oxide for the prevention and treatment of viral, bacterial, protozoal and fungal infections

Although the antimicrobial potential of nitric oxide (NO) is widely published, it is little used clinically. NO is a key signalling molecule modulating vascular, neuronal, inflammatory and immune responses. Endogenous antimicrobial activity is largely mediated by high local NO concentrations produced by cellular inducible nitric oxide synthase, and by derivative reactive nitrogen oxide species including peroxynitrite and S-nitrosothiols. NO may be taken as dietary substrate (inorganic nitrate, L-arginine), and therapeutically as gaseous NO, and transdermal, sublingual, oral, intranasal and intravenous nitrite or nitrate. Numerous preclinical studies have demonstrated that NO has generic static and cidal activities against viruses (including β-coronaviruses such as SARS-CoV-2), bacteria, protozoa and fungi/yeasts  in vitro. Therapeutic effects have been seen in animal models  in vivo, and phase II trials have demonstrated that NO donors can reduce microbial infection. Nevertheless, excess NO, as occurs in septic shock, is associated with increased morbidity and mortality. In view of the dose-dependent positive and negative effects of NO, safety and efficacy trials of NO and its donors are needed for assessing their role in the prevention and treatment of infections. Trials should test dietary inorganic nitrate for pre- or post-exposure prophylaxis and gaseous NO or oral, topical or intravenous nitrite and nitrate for treatment of mild-to-severe infections, including due to SARS-CoV-2 (COVID-19). This review summarises the evidence base from  in vitro, in vivo and early phase clinical studies of NO activity in viral, bacterial, protozoal and fungal infections.

Nitric oxide for the prevention and treatment of viral, bacterial, protozoal and fungal infections

Although the antimicrobial potential of nitric oxide (NO) is widely published, it is little used clinically. NO is a key signalling molecule modulating vascular, neuronal, inflammatory and immune responses. Endogenous antimicrobial activity is largely mediated by high local NO concentrations produced by cellular inducible nitric oxide synthase, and by derivative reactive nitrogen oxide species including peroxynitrite and S-nitrosothiols. NO may be taken as dietary substrate (inorganic nitrate, L-arginine), and therapeutically as gaseous NO, and transdermal, sublingual, oral, intranasal and intravenous nitrite or nitrate. Numerous preclinical studies have demonstrated that NO has generic static and cidal activities against viruses (including β-coronaviruses such as SARS-CoV-2), bacteria, protozoa and fungi/yeasts  in vitro. Therapeutic effects have been seen in animal models  in vivo, and phase II trials have demonstrated that NO donors can reduce microbial infection. Nevertheless, excess NO, as occurs in septic shock, is associated with increased morbidity and mortality. In view of the dose-dependent positive and negative effects of NO, safety and efficacy trials of NO and its donors are needed for assessing their role in the prevention and treatment of infections. Trials should test dietary inorganic nitrate for pre- or post-exposure prophylaxis and gaseous NO or oral, topical or intravenous nitrite and nitrate for treatment of mild-to-severe infections, including due to SARS-CoV-2 (COVID-19). This review summarises the evidence base from  in vitro, in vivo and early phase clinical studies of NO activity in viral, bacterial, protozoal and fungal infections.

Dietary nitrate and population health: a narrative review of the translational potential of existing laboratory studies

BACKGROUND

Dietary inorganic nitrate (NO3-) is a polyatomic ion, which is present in large quantities in green leafy vegetables and beetroot, and has attracted considerable attention in recent years as a potential health-promoting dietary compound. Numerous small, well-controlled laboratory studies have reported beneficial health effects of inorganic NO3- consumption on blood pressure, endothelial function, cerebrovascular blood flow, cognitive function, and exercise performance. Translating the findings from small laboratory studies into 'real-world' applications requires careful consideration.

MAIN BODY

This article provides a brief overview of the existing empirical evidence basis for the purported health-promoting effects of dietary NO3- consumption. Key areas for future research are then proposed to evaluate whether promising findings observed in small animal and human laboratory studies can effectively translate into clinically relevant improvements in population health. These proposals include: 1) conducting large-scale, longer duration trials with hard clinical endpoints (e.g. cardiovascular disease incidence); 2) exploring the feasibility and acceptability of different strategies to facilitate a prolonged increase in dietary NO3- intake; 3) exploitation of existing cohort studies to explore associations between NO3- intake and health outcomes, a research approach allowing larger samples sizes and longer duration follow up than is feasible in randomised controlled trials; 4) identifying factors which might account for individual differences in the response to inorganic NO3- (e.g. sex, genetics, habitual diet) and could assist with targeted/personalised nutritional interventions; 5) exploring the influence of oral health and medication on the therapeutic potential of NO3- supplementation; and 6) examining potential risk of adverse events with long term high- NO3- diets.

CONCLUSION

The salutary effects of dietary NO3- are well established in small, well-controlled laboratory studies. Much less is known about the feasibility and efficacy of long-term dietary NO3- enrichment for promoting health, and the factors which might explain the variable responsiveness to dietary NO3- supplementation between individuals. Future research focussing on the translation of laboratory data will provide valuable insight into the potential applications of dietary NO3- supplementation to improve population health.

Maternal microbiome in preeclampsia pathophysiology and implications on offspring health

Preeclampsia is a devastating hypertensive pregnancy disorder that currently affects 2%–8% of pregnancies worldwide. It is associated with maternal and fetal mortality and morbidity and adverse health outcomes both in mom and offspring beyond pregnancy. The pathophysiology is not completely understood, and there are no approved therapies to specifically treat for the disease, with only few therapies approved to manage symptoms. Recent advances suggest that aberrations in the composition of the microbiome may play a role in the pathogenesis of various diseases including preeclampsia. The maternal and uteroplacental environments greatly influence the long‐term health outcomes of the offspring through developmental programming mechanisms. The current review summarizes recent developments on the role of the microbiome in adverse pregnancy outcomes with a focus on preeclampsia. It also discusses the potential role of the maternal microbiome in fetal programming; explores gut‐targeted therapeutics advancement and their implications in the treatment of preeclampsia.

Potential of Beetroot and Blackcurrant Compounds to Improve Metabolic Syndrome Risk Factors

Metabolic syndrome (MetS) is a group of metabolic abnormalities, which together lead to increased risk of coronary heart disease (CHD) and type 2 diabetes mellitus (T2DM), as well as reduced quality of life. Dietary nitrate, betalains and anthocyanins may improve risk factors for MetS and reduce the risk of development of CHD and T2DM. Beetroot is a rich source of dietary nitrate, and anthocyanins are present in high concentrations in blackcurrants. This narrative review considers the efficacy of beetroot and blackcurrant compounds as potential agents to improve MetS risk factors, which could lead to decreased risk of CHD and T2DM. Further research is needed to establish the mechanisms through which these outcomes may occur, and chronic supplementation studies in humans may corroborate promising findings from animal models and acute human trials.

Enhanced Nitrite-Mediated Relaxation of Placental Blood Vessels Exposed to Hypoxia Is Preserved in Pregnancies Complicated by Fetal Growth Restriction

Nitric oxide (NO) is essential in the control of fetoplacental vascular tone, maintaining a high flow-low resistance circulation that favors oxygen and nutrient delivery to the fetus. Reduced fetoplacental blood flow is associated with pregnancy complications and is one of the major causes of fetal growth restriction (FGR). The reduction of dietary nitrate to nitrite and subsequently NO may provide an alternative source of NO in vivo. We have previously shown that nitrite induces vasorelaxation in placental blood vessels from normal pregnancies, and that this effect is enhanced under conditions of hypoxia. Herein, we aimed to determine whether nitrite could also act as a vasodilator in FGR. Using wire myography, vasorelaxant effects of nitrite were assessed on pre-constricted chorionic plate arteries (CPAs) and veins (CPVs) from normal and FGR pregnancies under normoxic and hypoxic conditions. Responses to the NO donor, sodium nitroprusside (SNP), were assessed in parallel. Nitrate and nitrite concentrations were measured in fetal plasma. Hypoxia significantly enhanced vasorelaxation to nitrite in FGR CPAs (p < 0.001), and in both normal (p < 0.001) and FGR (p < 0.01) CPVs. Vasorelaxation to SNP was also potentiated by hypoxia in both normal (p < 0.0001) and FGR (p < 0.01) CPVs. However, compared to vessels from normal pregnancies, CPVs from FGR pregnancies showed significantly lower reactivity to SNP (p < 0.01). Fetal plasma concentrations of nitrate and nitrite were not different between normal and FGR pregnancies. Together, these data show that nitrite-mediated vasorelaxation is preserved in FGR, suggesting that interventions targeting this pathway have the potential to improve fetoplacental blood flow in FGR pregnancies.

A Narrative Review on Dietary Strategies to Provide Nitric Oxide as a Non-Drug Cardiovascular Disease Therapy: Beetroot Formulations-A Smart Nutritional Intervention

Beetroot is a remarkable vegetable, as its rich nitrate and bioactive compound contents ameliorate cardiovascular and metabolic functions by boosting nitric oxide synthesis and regulating gene expressions or modulating proteins and enzyme activities involved in these cellular processes. Dietary nitrate provides a physiological substrate for nitric oxide production, which promotes vasodilatation, increases blood flow and lowers blood pressure. A brief narrative and critical review on dietary nitrate intake effects are addressed herein by considering vegetable sources, dosage, intervention regimen and cardioprotective effects achieved in both healthy and cardiovascular-susceptible individuals. Compared to other nitrate-rich vegetables, beets were proven to be the best choice for non-drug therapy because of their sensorial characteristics and easy formulations that facilitate patient adherence for long periods, allied to bioaccessibility and consequent effectiveness. Beets were shown to be effective in raising nitrate and nitrite in biological fluids at levels capable of promoting sustained improvement in primary and advanced hemodynamic parameters.

Antioxidant Food Components for the Prevention and Treatment of Cardiovascular Diseases: Effects, Mechanisms, and Clinical Studies

Cardiovascular diseases (CVDs) have gained increasing attention because of their high prevalence and mortality worldwide. Epidemiological studies revealed that intake of fruits, vegetables, nuts, and cereals could reduce the risk of CVDs, and their antioxidants are considered as the main contributors. Moreover, experimental studies showed that some antioxidant natural products and their bioactive compounds exerted beneficial effects on the cardiovascular system, such as polyphenols, polysaccharides, anthocyanins, epigallocatechin gallate, quercetin, rutin, and puerarin. The mechanisms of action mainly included reducing blood pressure, improving lipid profile, ameliorating oxidative stress, mitigating inflammation, and regulating gut microbiota. Furthermore, clinical trials confirmed the cardiovascular-protective effect of some antioxidant natural products, such as soursop, beetroot, garlic, almond, and green tea. In this review, we summarized the effects of some antioxidant natural products and their bioactive compounds on CVDs based on the epidemiological, experimental, and clinical studies, with special attention paid to the relevant mechanisms and clinical trials.

Pharmacokinetics of Nitrate and Nitrite Following Beetroot Juice Drink Consumption

BACKGROUND

Nitrate (NO₃ ^-)-rich beetroot (BR) juice supplementation has been shown to improve cardiovascular function via reduction to nitrite (NO₂ ^-) and then to the bioactive molecule nitric oxide (NO). However, limited research exists for the role of inorganic NO₂ ^- that is contained naturally within BR.

OBJECTIVE

As BR juice can naturally contain both NO₃ ^- and NO₂ ^- the objective of this study was to evaluate the individual effects of NO₃ ^- and NO₂ ^- consumed from BR on plasma [NO₃ ^-]/[NO₂ ^-] and their subsequent effects on various cardiovascular measures.

DESIGN

In four separate treatments, 11 healthy adults consumed 250 mL of BR containing one of the following: (i) high NO₃ ^-, low NO₂ ^- (HL; 572 mg NO₃ ^-, 32 mg NO₂ ^-); (ii) medium NO₃ ^-, medium NO₂ ^- (MM; 280 mg NO₃ ^-, 237 mg NO₂ ^-); (iii) low NO₃ ^-, medium NO₂ ^- (LM; 43 mg NO₃ ^-, 262 mg NO₂ ^-); (iv) placebo (PL; low NO₃ ^-, low NO₂ ^-: 8 mg NO₃ ^-, 5.8 mg NO₂ ^-). Plasma [NO₃ ^-]/[NO₂ ^-], blood pressure, heart rate, mean arterial pressure (MAP), cardiac output and stroke volume were measured at baseline and every hour or second hour for 6 h post-BR consumption.

OUTCOMES

Ingestion of the HL and MM BR increased plasma [NO₂ ^-] and [NO₃ ^-] after 2 h, with both remaining elevated after 6 h (p < 0.05). LM increased plasma [NO₃ ^-] (p < 0.05) but did not increase plasma [NO₂ ^-] compared to PL (p = 0.177). MAP was lower following the consumption of HL at 4 h and LM at 6 h (p < 0.05).

CONCLUSION

Inorganic NO₃ ^- consumption is the critical factor in elevating plasma [NO₃ ^-] and [NO₂ ^-]; however, both NO₂ ^- and NO₃ ^- show potential to reduce MAP. The known reduction of systolic blood pressure (SBP)/diastolic blood pressure (DBP) following NO₃ ^- supplementation was not observed, making it unclear if NO₂ ^- contributes to a reduction in SBP/DBP alongside NO₃ ^-.

Placental blood flow sensing and regulation in fetal growth restriction

The mechanical force of blood flow is a fundamental determinant of vascular homeostasis. This frictional stimulation of cells, fluid shear stress (FSS), is increasingly recognised as being essential to placental development and function. Here, we focus on the role of FSS in regulating fetoplacental circulatory flow, both in normal pregnancy and that affected by fetal growth restriction (FGR).

The fetus is reliant on placental perfusion to meet its circulatory and metabolic demands. Failure of normal vascular adaptation and the mechanisms enabling responsive interaction between fetoplacental and maternal circulations can result in FGR. FSS generates vasodilatation at least partly through the release of endothelial nitric oxide, a process thought to be vital for adequate blood flow. Where FGR is caused by placental dysfunction, placental vascular anatomy is altered, alongside endothelial dysfunction and hypoxia, each impacting upon the complex balance of FSS forces.

Identifying specific mechanical sensors and the mechanisms governing how FSS force is converted into biochemical signals is a fast-paced area of research. Here, we raise awareness of Piezo1 proteins, recently discovered to be FSS-sensitive in fetoplacental endothelium, and with emerging roles in NO generation, vascular tone and angiogenesis. We discuss the emerging concept that activating mechanosensors such as Piezo1 ultimately results in the orchestrated processes of placental vascular adaptation. Piecing together the mechanisms governing endothelial responses to FSS in placental insufficiency is an important step towards developing new treatments for FGR.

Sulforaphane Bioavailability and Effects on Blood Pressure in Women with Pregnancy Hypertension

Sulforaphane, an isothiocyanate found in cruciferous vegetables such as broccoli, shows promise as an adjuvant therapy for preeclampsia. To inform future clinical trials, we set out to determine the bioavailability of sulforaphane in non-pregnant and preeclamptic women. In six healthy female volunteers, we performed a crossover trial to compare the bioavailability of sulforaphane and metabolites afforded by an activated and non-activated broccoli extract preparation. We then undertook a dose escalation study of the activated broccoli extract in 12 women with pregnancy hypertension. In non-pregnant women, an equivalent dose of activated broccoli extract gave higher levels of sulforaphane and metabolites than a non-activated extract (p < 0.0001) and greater area under the curve (AUC) (3559 nM vs. 2172 nM, p = 0.03). Compared to non-pregnant women, in women with preeclampsia, the same dose of activated extract gave lower levels of total metabolites (p < 0.000) and AUC (3559 nM vs. 1653 nM, p = 0.007). Doubling the dose of the activated extract in women with preeclampsia doubled levels of sulforaphane and metabolites (p = 0.02) and AUC (1653 nM vs. 3333 nM, p = 0.02). In women with preeclampsia, activated broccoli extract was associated with modest decreases in diastolic blood pressure (p = 0.05) and circulating levels of sFlt-1 (p = 0.0002). A myrosinase-activated sulforaphane formulation affords better sulforaphane bioavailability than a non-activated formulation. Higher doses of sulforaphane are required to achieve likely effective doses in pregnant women than in non-pregnant women. Sulforaphane may improve endothelial function and blood pressure in women with pregnancy hypertension.

Effect of Dietary Nitrate Supplementation on Sleep in Chronic Obstructive Pulmonary Disease Patients

PURPOSE

Poor sleep quality in chronic obstructive pulmonary disease (COPD) is a result of oxygen desaturation secondary to compromised lung function. Nitrate supplementation with dietary beetroot juice is known to elevate plasma nitrate and to increase the efficiency of oxygen utilization in non-COPD individuals; whether it is of therapeutic benefit for sleep quality in COPD has not been reported.

PATIENTS AND METHODS

In a counterbalanced within-subjects design involving 15 COPD patients as subjects, the subjects consumed either beetroot juice containing nitrate (BJ; ∼6.2 mmol NO₃ ^-) or placebo (NO₃ ^- -depleted juice) immediately before a night of polysomnographic monitoring. Nitrate was measured in plasma collected immediately after waking.

RESULTS

While BJ consumption had no effect on the amount of time spent in any sleep stages, wake-to-N2 transitions and direct wake-to-rapid eye movement sleep (REMS) transitions, hallmarks of disordered sleep, were less frequent on the BJ night than on the placebo night. In the last two hours of the BJ night, percent time in REMS increased and delta power during deep (N3) non-REMS decreased, relative to the placebo night. Collectively, the reduced frequency of atypical transitions and the normalization of non-REMS/REMS dynamics after BJ are indicative of an improvement of sleep quality. BJ also resulted in sustained elevation of peripheral oxygen saturation (SpO₂), during episodes of wake after sleep onset. Plasma nitrate was elevated nearly tenfold on the morning after BJ relative to placebo.

CONCLUSION

BJ has a normalizing effect on disordered sleep in COPD, which may be related to improved oxygen delivery.

CLINICAL TRIAL REGISTRATION

The activities of the Regional Committees for Medical and Health Research Ethics (REC) are founded on the Norwegian law on research ethics and medical research. This study was approved by NTNU/REK midt, Det medisinske fakultet, Postboks 8905, 7491 Trondheim (REK midt 2016/1360).

Postnatal Enalapril to Improve Cardiovascular Function Following Preterm Preeclampsia (PICk-UP):: A Randomized Double-Blind Placebo-Controlled Feasibility Trial

Hypertensive disease in pregnancy is associated with future cardiovascular disease and, therefore, provides an opportunity to identify women who could benefit from targeted interventions aimed at reducing cardiovascular morbidity. This study focused on the highest-risk group, women with preterm preeclampsia, who have an 8-fold risk of death from future cardiovascular disease. We performed a single-center feasibility randomized controlled trial of 6 months' treatment with enalapril to improve postnatal cardiovascular function. Echocardiography and hemodynamic measurements were performed at baseline (<3 days), 6 weeks, and 6 months postdelivery on 60 women. At randomization, 88% of women had diastolic dysfunction, and 68% had concentric remodeling/hypertrophy. No difference was seen in total vascular resistance (P=0.59) or systolic function (global longitudinal strain: P=0.14) between groups at 6 months. However, women treated with enalapril had echocardiographic measurements consistent with improved diastolic function (E/E'[the ratio of early mitral inflow velocity and early mitral annular diastolic velocity]: P=0.04) and left ventricular remodeling (relative wall thickness: P=0.01; left ventricular mass index: P=0.03) at 6 months, compared with placebo. Urinary enalapril was detectable in 85% and 63% of women in the enalapril arm at 6 weeks and 6 months, respectively. All women responded positively to taking enalapril in the future. Our study confirmed acceptability and feasibility of the study protocol with a recruitment to completion rate of 2.2 women per month. Importantly, postnatal enalapril treatment was associated with improved echocardiographic measurements; these early improvements have the potential to reduce long-term cardiovascular disease risk. A definitive, multicenter randomized controlled trial is now required to confirm these findings. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT03466333.

Red Beetroot. A Potential Source of Natural Additives for the Meat Industry

Currently, the food industry is looking for alternatives to synthetic additives in processed food products, so research investigating new sources of compounds with high biological activity is worthwhile and becoming more common. There are many different types of vegetables that contain bioactive compounds, and additional features of some vegetables include uses as natural colorants and antioxidants. In this sense, and due to the special composition of beetroot, the use of this vegetable allows for the extraction of a large number of compounds with special interest to the meat industry. This includes colorants (betalains), antioxidants (betalains and phenolic compounds), and preservatives (nitrates), which can be applied for the reformulation of meat products, thus limiting the number and quantity of synthetic additives added to these foods and, at the same time, increase their shelf-life. Despite all these benefits, the application of beetroot or its products (extracts, juice, powder, etc.) in the meat industry is very limited, and the body of available research on beetroot as an ingredient is scarce. Therefore, in this review, the main biologically active compounds present in beetroot, the implications and benefits that their consumption has for human health, as well as studies investigating the use beetroot in the reformulation of meat and meat products are presented in a comprehensible manner.

Nitrate and nitrite-based therapy to attenuate cardiovascular remodelling in arterial hypertension

Hypertension is a highly prevalent disease marked by vascular and cardiac maladaptive remodelling induced mainly by renin-angiotensin system activation followed by oxidative stress. Here, we briefly describe these damages and review the current evidence supporting a potential role for nitrate and nitrite as antihypertensive molecules that act via nitric oxide (NO) formation-dependent and NO formation-independent mechanisms and how nitrate/nitrite inhibits cardiovascular remodelling in hypertension. The renin-angiotensin system activation and oxidative stress converge to activate proteases involved in cardiovascular remodelling in hypertension. Besides these proteases, several investigations have demonstrated that reduced endogenous NO bioavailability is a central pathological event in hypertension. In this regard, nitrate/nitrite, long considered inert products of NO, is now known as physiological molecules able to reduce blood pressure in hypertensive patients and in different experimental models of hypertension. These effects are associated with the formation of NO and other NO-related molecules, which could induce S-nitrosylation of target proteins. However, it remains unclear whether S-nitrosylation is an essential mechanism for the anti-remodelling effects of nitrate/nitrite in hypertension. Moreover, nitrate/nitrite produces antioxidant effects associated with the inhibition of signalling pathways involved in cardiovascular remodelling. Together, these findings may help to establish nitrate and nitrite as effective therapies in hypertension-induced cardiovascular remodelling.

Does the Oral Microbiome Play a Role in Hypertensive Pregnancies?

Chronic hypertension during gestation is associated with an increased risk of adverse pregnancy outcomes including pre-eclampsia, fetal growth restriction and preterm birth. Research into new chemotherapeutic regimes for the treatment of hypertension in pregnancy is limited due to concerns about fetal toxicity and teratogenicity, and new therapeutic avenues are being sought in alternative physiological pathways. Historically, generation of the vasodilator nitric oxide was believed to be solely from L-arginine by means of nitric oxide synthase enzymes. Recently, a novel pathway for the reduction of dietary inorganic nitrate to nitrite by the bacteria in the oral cavity and subsequently to vasodilatory nitric oxide within the body has been uncovered. Dietary nitrate is abundant in green leafy vegetables, including beetroot and spinach, and reduction of exogenous nitrate to nitrite by oral bacteria can increase nitric oxide in the vasculature, lessening hypertension. Supplements rich in nitrate may be an attractive choice for treatment due to fewer side effects than drugs that are currently used to treat hypertensive pregnancy disorders. Additionally, manipulation of the composition of the oral microbiota using pro- and prebiotics in tandem with additional dietary interventions to promote cardiovascular health during gestation may offer a safe and effective means of treating hypertensive pregnancy disorders including gestational hypertension and pre-eclampsia. The use of dietary inorganic nitrate as a supplement during pregnancy requires further exploration and large scale studies before it may be considered as part of a treatment regime. The aim of this article is to review the current evidence that oral microbiota plays a role in hypertensive pregnancies and whether it could be manipulated to improve patient outcomes.

Beetroot juice lowers blood pressure and improves endothelial function in pregnant eNOS-/- mice: importance of nitrate-independent effects

KEY POINTS

Maternal hypertension is associated with increased rates of pregnancy pathologies, including fetal growth restriction, due at least in part to reductions in nitric oxide (NO) bioavailability and associated vascular dysfunction. Dietary nitrate supplementation, from beetroot juice (BRJ), has been shown to increase NO bioavailability and improve cardiovascular function in both preclinical and clinical studies. This study is the first to investigate effects of dietary nitrate supplementation in a pregnant animal model. Importantly, the effects of nitrate-containing BRJ were compared with both 'placebo' (nitrate-depleted) BRJ as well as water to control for potential nitrate-independent effects. Our data show novel, nitrate-independent effects of BRJ to lower blood pressure and improve vascular function in endothelial nitric oxide synthase knockout (eNOS^-/- ) mice. These findings suggest potential beneficial effects of BRJ supplementation in pregnancy, and emphasize the importance of accounting for nitrate-independent effects of BRJ in study design and interpretation.

ABSTRACT

Maternal hypertension is associated with adverse pregnancy outcomes, including fetal growth restriction (FGR), due in part to reductions in nitric oxide (NO) bioavailability. We hypothesized that maternal dietary nitrate administration would increase NO bioavailability to reduce systolic blood pressure (SBP), improve vascular function and increase fetal growth in pregnant endothelial NO synthase knockout (eNOS^-/- ) mice, which exhibit hypertension, endothelial dysfunction and FGR. Pregnant wildtype (WT) and eNOS^-/- mice were supplemented with nitrate-containing beetroot juice (BRJ+) from gestational day (GD) 12.5. Control mice received an equivalent dose of nitrate-depleted BRJ (BRJ-) or normal drinking water. At GD17.5, maternal SBP was measured; at GD18.5, maternal nitrate/nitrite concentrations, uterine artery (UtA) blood flow and endothelial function were assessed, and pregnancy outcomes were determined. Plasma nitrate concentrations were increased in both WT and eNOS^-/- mice supplemented with BRJ+ (P < 0.001), whereas nitrite concentrations were increased only in eNOS^-/- mice (P < 0.001). BRJ- did not alter nitrate/nitrite concentrations. SBP was lowered and UtA endothelial function was enhanced in eNOS^-/- mice supplemented with either BRJ+ or BRJ-, indicating nitrate-independent effects of BRJ. Improvements in endothelial function in eNOS^-/- mice were abrogated in the presence of 25 mm KCl, implicating enhanced EDH signalling in BRJ- treated animals. At GD18.5, eNOS^-/- fetuses were significantly smaller than WT animals (P < 0.001), but BRJ supplementation did not affect fetal weight. BRJ may be a beneficial intervention in pregnancies associated with hypertension, endothelial dysfunction and reduced NO bioavailability. Our data showing biological effects of non-nitrate components of BRJ have implications for both interpretation of previous findings and in the design of future clinical trials.

Functional properties of beetroot (Beta vulgaris) in management of cardio-metabolic diseases

Red beetroot (Beta vulgaris), as a naturally occurring root vegetable and a rich source of phytochemicals and bioactive compounds, is known for its beneficial roles in the improvement of several clinical and pathologic outcome. Chronic and acute beetroot juice supplementation, as a cost-effective strategy, is proposed to hold promises in controlling diabetes and insulin hemostasis, blood pressure and vascular function, renal health and the possible effect on microbiome abundance. The secondary outcome and physiological response of microbiome abundance modulation included the non- significant fluctuation of systolic and diastolic blood pressures. Also, some studies have suggested a reno-protective property of beetroot juice that is associated with the reduction of mortality rate and favorable changes in kidney’s functional parameters among patients with renal disorders. Similarly, it is shown that the persistent consumption of beetroot juice effectively postpones the postprandial glycemic response and decreases the blood glucose peak. The significant blood pressure lowering effect has been seen among normotensive subjects, which tend to be more considerable among hypertensive individuals and progressive among overweight adults.

Within this context, this review aims to provide a comprehensive overview on the therapeutic applications of beetroot juice in metabolic disorders and theirs underlying mechanisms. Despite the inconsistencies in the set of results from the reviewed studies, there is no doubt that further contributing factors must be investigated more deeply in future studies.

The Role of Nitric Oxide, ADMA, and Homocysteine in The Etiopathogenesis of Preeclampsia-Review

Preeclampsia is a serious, pregnancy-specific, multi-organ disease process of compound aetiology. It affects 3–6% of expecting mothers worldwide and it persists as a leading cause of maternal and foetal morbidity and mortality. In fact, hallmark features of preeclampsia (PE) result from vessel involvement and demonstrate maternal endothelium as a target tissue. Growing evidence suggests that chronic placental hypoperfusion triggers the production and release of certain agents that are responsible for endothelial activation and injury. In this review, we will present the latest findings on the role of nitric oxide, asymmetric dimethylarginine (ADMA), and homocysteine in the etiopathogenesis of preeclampsia and their possible clinical implications.