Acute Effects of an Oral Nitric Oxide Supplement on Blood Pressure, Endothelial Function, and Vascular Compliance in Hypertensive Patients

Oral Microbiome Dysbiosis as a Risk Factor for Stroke: A Comprehensive Review

Stroke represents a significant global health burden, with a substantial impact on mortality, morbidity, and long-term disability. The examination of stroke biomarkers, particularly the oral microbiome, offers a promising avenue for advancing our understanding of the factors that contribute to stroke risk and for developing strategies to mitigate that risk. This review highlights the significant correlations between oral diseases, such as periodontitis and caries, and the onset of stroke. Periodontal pathogens within the oral microbiome have been identified as a contributing factor in the exacerbation of risk factors for stroke, including obesity, dyslipidemia, atherosclerosis, hypertension, and endothelial dysfunction. The alteration of the oral microbiome may contribute to these conditions, emphasizing the vital role of oral health in the prevention of cardiovascular disease. The integration of dental and medical health practices represents a promising avenue for enhancing stroke prevention efforts and improving patient outcomes.

Oral Supplementation with Betaine Powder Ameliorated High Blood Pressure in Spontaneously Hypertensive Rats

Supplementation of betaine is associated with improved cardiac health, potentially due to its function in re-methylation of homocysteine, an independent risk factor for cardiovascular diseases. We investigated the effects of oral betaine supplementation on blood pressure homeostasis in spontaneously hypertensive (SHR) rats and Wistar Kyoto (WKY) rats in an 8 week-feeding trial with control (SHR-con and WKY-con) and 1% betaine supplemented (SHR-b and WKY-b) diets. Systolic, diastolic, and mean blood pressure in the SHR-b group were significantly lower at week 8 (p = 0.013, p = 0.011, p = 0.010, respectively). Furthermore, serum nitric oxide (NO) levels were significantly (p < 0.05) improved in the WKY-b and SHR-b groups, suggesting a healthy endothelial function. Additionally, the serum angiotensin I converting enzyme level in SHR-b rats was also significantly lowered, which may have been another reason for lower blood pressure. A significantly higher non-HDL level in the SHR-b group might reflect enhanced lipid secretion into the circulation in the form of very-low-density lipoprotein (VLDL). Betaine is known for its effect on the synthesis of phosphatidylcholine, a key component of VLDL. However, the long-term net outcomes of both blood pressure lowering and serum lipid increment should be further studied.

Early-onset alcohol, tobacco, and illicit drug use with age at onset of hypertension: a survival analysis

PURPOSE

To examine the associations of age when first substance use and early-onset substance use before age 18 with age at onset (AAO) of hypertension.

METHODS

This study included 19,270 individuals with AAO of hypertension from the 2015-2019 National Survey on Drug Use and Health. Age when first use of 10 substance use variables included alcohol, daily cigarettes, cigars, smokeless tobacco, marijuana, cocaine, hallucinogens, lysergic acid diethylamide (LSD), inhalants, and methamphetamine use. The outcome was AAO of hypertension and variable cluster analysis was used to classify the exposures and outcome. Substance use status was classified into three categories: early-onset substance use (first used substance before age 18), late-onset substance use (first used substance after age 18), and never used.

RESULTS

The mean AAO of hypertension was 42.7 years. Age when first use of 10 substance use variables had significant correlations with AAO of hypertension (all p values < 0.001). Individuals with early-onset alcohol, cigars, smokeless tobacco, marijuana, hallucinogens, inhalants, cocaine, LSD, and methamphetamine use revealed significantly earlier onset of hypertension than those never used. Compared with never used substances, the Cox regression model showed that early-onset alcohol, smokeless tobacco, marijuana, inhalants, and methamphetamine use had an increased risk of AAO of hypertension [hazard ratio (HR) (95%CI) = 1.22 (1.13, 1.31), 1.36 (1.24, 1.49), 1.85 (1.75, 1.95), 1.41 (1.30, 1.52), and 1.27 (1.07,1.50), respectively].

CONCLUSION

These findings suggest that intervention strategies or programs focusing on preventing early-onset substance use before age 18 may delay the onset of adult hypertension.

Addressing the Missing Links in Cardiovascular Aging

The aim of this manuscript is to provide a review of available options to enhance cardiovascular health and prevent cardiovascular disease (CVD) in the aging population using a systems-biology approach. These include the role of the gut microbiome, the early identification and removal of environmental toxins, and finally age related sex hormones and supplement replacement which all influence aging. Implementing such a comprehensive approach has the potential to facilitate earlier risk assessment, disease prevention, and even improve mortality. Further study in these areas will continue to advance our understanding and refine therapeutic interventions for a healthier cardiovascular aging process.

Oral nitrate-reducing bacteria as potential probiotics for blood pressure homeostasis

Hypertension is a leading cause of morbidity and mortality worldwide and poses a major risk factor for cardiovascular diseases and chronic kidney disease. Research has shown that nitric oxide (NO) is a vasodilator that regulates vascular tension and the decrease of NO bioactivity is considered one of the potential pathogenesis of essential hypertension. The L-arginine-nitric oxide synthase (NOS) pathway is the main source of endogenous NO production. However, with aging or the onset of diseases, the function of the NOS system becomes impaired, leading to insufficient NO production. The nitrate-nitrite-NO pathway allows for the generation of biologically active NO independent of the NOS system, by utilizing endogenous or dietary inorganic nitrate and nitrite through a series of reduction cycles. The oral cavity serves as an important interface between the body and the environment, and dysbiosis or disruption of the oral microbiota has negative effects on blood pressure regulation. In this review, we explore the role of oral microbiota in maintaining blood pressure homeostasis, particularly the connection between nitrate-reducing bacteria and the bioavailability of NO in the bloodstream and blood pressure changes. This review aims to elucidate the potential mechanisms by which oral nitrate-reducing bacteria contribute to blood pressure homeostasis and to highlight the use of oral nitrate-reducing bacteria as probiotics for oral microbiota intervention to prevent hypertension.

Effects of S-Allylcysteine-Rich Garlic Extract and Dietary Inorganic Nitrate Formula on Blood Pressure and Salivary Nitric Oxide: An Open-Label Clinical Trial Among Hypertensive Subjects

INTRODUCTION

 The conversion of dietary inorganic nitrate (NO3-) to nitric oxide (NO) is a non-canonical pathway that plays an important role in NO biology, especially under pathological conditions. Inorganic NO3- supplementation is a proven method for controlling mild hypertension. Recent reports have suggested that another gaseous transmitter, hydrogen sulfide (H2S), influences NO biosynthesis and metabolism. Here, data are presented from an open-label clinical trial examining the effect of an encapsulated formulation (Vascanox® HP) that combines dietary sources of inorganic NO3- and S-allylcysteine (SAC), a source of H2S from garlic, on NO bioavailability and blood pressure in subjects experiencing elevated blood pressure or mild hypertension.

METHODS

 An open-label clinical trial was conducted among patients with hypertension. Participants took Vascanox® for four weeks. Blood pressure was measured at baseline, two weeks, and four weeks. Salivary nitrite (NO2-), a surrogate of NO bioavailability, and NO3- were assessed prior to and two, six, and 24 hours after dosing on the first day of the study and prior to and two hours after dosing at subsequent study visits using saliva NO test strips. Changes in study outcomes over time were evaluated via analysis of variance (ANOVA) and paired t-tests.

RESULTS

 Twelve participants completed the clinical trial. Vascanox® HP decreased systolic blood pressure by ~11 mmHg (p < 0.001) at two weeks and persisted beyond four weeks with daily supplementation. It also decreased the diastolic blood pressure of hypertensive subjects but not normotensive ones. The magnitude of the decrease was 11 mmHg (p < 0.01) at four weeks of study. Measurements of salivary concentrations of NO2- revealed high peak levels (743 uM) at two hours post-administration and a slow decay to elevated levels (348 uM) at 24 hours. NO2- salivary concentrations, a surrogate biomarker of NO bioavailability, remained above baseline for the duration of the study.

CONCLUSIONS

 Vascanox® HP was shown to be a safe, effective, quick-acting, and long-lasting dietary supplement for controlling mild hypertension.

Glu298Asp variant of the endothelial nitric oxide synthase gene and acute coronary syndrome or premature coronary artery disease: A systematic review and meta-analysis

INTRODUCTION

Several published studies have reported an association between the Glu298Asp polymorphism (rs1799983), residing in the endothelial nitric oxide synthase (NOS3) gene, and lower levels of circulating nitric oxide, as well as an increased risk of coronary artery disease (CAD). However, association status of this genetic variant with acute coronary syndrome (ACS) or premature CAD (PCAD) is still unclear. Against this background, we conducted a systematic review and study level meta-analysis to assess the association of the NOS3 Glu298Asp polymorphism with ACS or PCAD.

MATERIALS AND METHODS

A comprehensive online search to identify relevant studies was performed on several databases including PubMed, EMBASE, MEDLINE, Scopus, Cochrane library and Web of Science. The identified studies were stratified into two ancestral subgroups: 'European ancestry' and 'All other ancestries combined'. Study level odds ratios (ORs) and their 95% confidence intervals (CI) were pooled using random/fixed effects employing a Z test.

RESULTS

Out of a total of 195 distinct records identified through online search, 37 articles with 39 different studies, with a total sample size of 27,441 (11,516 cases/15,925 controls) were included for quantitative synthesis. Pooled results suggested significant associations of the NOS3 Glu298Asp polymorphism with ACS or PCAD through dominant as well as allelic genetic models (p ≤ 0.002), primarily driven by the 'All other ancestries combined' subgroup. The 'All other ancestries combined' subgroup demonstrated an additional risk of 36% for ACS or PCAD, through both dominant and allelic genetic models (OR = 1.36, 95%CI = 1.13, 1.63, p = 0.001 and OR = 1.36, 95%CI = 1.14, 1.61, p = 0.0005 respectively). On the other hand, the 'European ancestry' subgroup did not show any significant associations. Sensitivity analysis and a sub-analysis for the myocardial infarction endpoint further supported these observed associations.

CONCLUSIONS

This meta-analysis indicates towards an association between the NOS3 Glu298Asp polymorphism and ACS or PCAD, predominantly driven by 'All other ancestries combined' subgroup. In contrast, the 'European ancestry' subgroup did not demonstrate any significant association. Further large-scale investigations are required to confirm our derived results.

Acute beetroot juice consumption does not alter cerebral autoregulation or cardiovagal baroreflex sensitivity during lower-body negative pressure in healthy adults

Introduction

Beetroot juice (BRJ) improves peripheral endothelial function and vascular compliance, likely due to increased nitric oxide bioavailability. It is unknown if BRJ alters cerebrovascular function and cardiovagal baroreflex control in healthy individuals.

Purpose

We tested the hypotheses that BRJ consumption improves cerebral autoregulation (CA) and cardiovagal baroreflex sensitivity (cBRS) during lower-body negative pressure (LBNP).

Methods

Thirteen healthy adults (age: 26 ± 4 years; 5 women) performed oscillatory (O-LBNP) and static LBNP (S-LBNP) before (PRE) and 3 h after consuming 500 mL of BRJ (POST). Participants inhaled 3% CO2 (21% O2, 76% N2) during a 5 min baseline and throughout LBNP to attenuate reductions in end-tidal CO2 tension (PETCO2). O-LBNP was conducted at ∼0.02 Hz for six cycles (-70 mmHg), followed by a 3-min recovery before S-LBNP (-40 mmHg) for 7 min. Beat-to-beat middle cerebral artery blood velocity (MCAv) (transcranial Doppler) and blood pressure were continuously recorded. CA was assessed using transfer function analysis to calculate coherence, gain, and phase in the very-low-frequency (VLF; 0.020-0.070 Hz) and low-frequency bands (LF; 0.07-0.20 Hz). cBRS was calculated using the sequence method. Comparisons between POST vs. PRE are reported as mean ± SD.

Results

During O-LBNP, coherence VLF was greater at POST (0.55 ± 0.06 vs. 0.46 ± 0.08; P < 0.01), but phase VLF (P = 0.17) and gain VLF (P = 0.69) were not different. Coherence LF and phase LF were not different, but gain LF was lower at POST (1.03 ± 0.20 vs. 1.12 ± 0.30 cm/s/mmHg; P = 0.05). During S-LBNP, CA was not different in the VLF or LF bands (all P > 0.10). Up-cBRS and Down-cBRS were not different during both LBNP protocols.

Conclusion

These preliminary data indicate that CA and cBRS during LBNP in healthy, young adults is largely unaffected by an acute bolus of BRJ.

Effects of Fermented Garlic Extract Containing Nitric Oxide Metabolites on Blood Flow in Healthy Participants: A Randomized Controlled Trial

Aged or fermented garlic extract (FGE) is a natural remedy that improves vascular function through increasing vascular nitric oxide (NO) bioavailability. This is because nitrite (NO2-), a NO metabolite, can be produced through bioconversion with macrobacteria during the fermentation of foods like garlic. We aimed to evaluate the effects of NO2- in FGE on blood flow (BF), blood pressure (BP), velocity of the common carotid artery (CCA) and internal carotid artery (ICA), regional cerebral BF (rCBF), and peripheral BF (PBF). The study was divided into two parts: (1) Thirty healthy adults were divided into FGE and placebo groups to compare BP and velocity of the CCA and ICA; and (2) Twenty-eight healthy adults were divided into FGE and placebo groups to compare rCBF and PBF and determine changes before/after ingestion. Significant changes were noted in BP and the velocity of both CCA 30-60 min after FGE ingestion. FGE ingestion resulted in significant increases in rCBF and increases in body surface temperature through alterations in PBF. No detectable clinical side effects were noted. Overall, oral administration of NO2- containing FGE demonstrated acute positive effects in upregulating BF, including the CCA, BP, rCBF, and PBF. Follow-up studies with larger sample sizes and long-term ingestion may be needed.

Post-exposure persistence of nitric oxide upregulation in skin cells irradiated by UV-A

Evidence suggests that exposure to UV-A radiation can liberate nitric oxide from skin cells eliciting vasodilation in-vivo. However, the duration of nitric oxide release in skin cells after UV exposure is not well studied, with emphasis on UV-B mediated iNOS upregulation. The current study demonstrated persistence of nitric oxide release in a dark reaction after moderate UV-A exposure, peaking around 48 h post exposure; this effect was shown in keratinocytes, fibroblasts and endothelial cells from neonatal donors and keratinocytes from aged donors and confirmed the hypothesis that UV-A exposure appeared to upregulate cNOS alongside iNOS. Release of nitric oxide in the skin cells induced by a moderate exposure to UV-A in sunlight may be especially beneficial for some demographic groups such as the elderly, hypertensive patients or those with impaired nitric oxide function, not only during exposure but many hours and days after that.

Flavonoids in Treatment of Chronic Kidney Disease

Chronic kidney disease (CKD) is a progressive systemic disease, which changes the function and structure of the kidneys irreversibly over months or years. The final common pathological manifestation of chronic kidney disease is renal fibrosis and is characterized by glomerulosclerosis, tubular atrophy, and interstitial fibrosis. In recent years, numerous studies have reported the therapeutic benefits of natural products against modern diseases. Substantial attention has been focused on the biological role of polyphenols, in particular flavonoids, presenting broadly in plants and diets, referring to thousands of plant compounds with a common basic structure. Evidence-based pharmacological data have shown that flavonoids play an important role in preventing and managing CKD and renal fibrosis. These compounds can prevent renal dysfunction and improve renal function by blocking or suppressing deleterious pathways such as oxidative stress and inflammation. In this review, we summarize the function and beneficial properties of common flavonoids for the treatment of CKD and the relative risk factors of CKD.

Potential therapeutic effects and applications of Eucommiae Folium in secondary hypertension

Eucommiae Folium (EF), a traditional Chinese medicine, has been used to treat secondary hypertension, including renal hypertension and salt-sensitive hypertension, as well as hypertension caused by thoracic aortic endothelial dysfunction, a high-fat diet, and oxidized low-density lipoprotein. The antihypertensive components of EF are divided into four categories: flavonoids, iridoids, lignans, and phenylpropanoids, such as chlorogenic acid, geniposide acid and pinoresinol diglucoside. EF regulates the occurrence and development of hypertension by regulating biological processes, such as inhibiting inflammation, regulating the nitric oxide synthase pathway, reducing oxidative stress levels, regulating endothelial vasoactive factors, and lowering blood pressure. However, its molecular antihypertensive mechanisms are still unclear and require further investigation. In this review, by consulting the relevant literature on the antihypertensive effects of EF and using network pharmacology, we summarized the active ingredients and pharmacological mechanisms of EF in the treatment of hypertension to clarify how EF is associated with secondary hypertension, the related components, and underlying mechanisms. The results of the network pharmacology analysis indicated that EF treats hypertension through a multi-component, multi-target and multi-pathway mechanism. In particular, we discussed the role of EF targets in the treatment of hypertension, including epithelial sodium channel, heat shock protein70, rho-associated protein kinase 1, catalase, and superoxide dismutase. The relevant signal transduction pathways, the ras homolog family member A (RhoA)/Rho-associated protein kinase (ROCK) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase/eNOS/NO/Ca²⁺ pathways, are also discussed.

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Eucommiae Folium (EF) treats secondary hypertension via the RhoA/ROCK1 and NO/sGC/cGMP pathways.

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EF inhibits oxidative stress and improves endothelial dysfunction to treat hypertension.

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EF's antihypertensive components are phenylpropanoids, flavonoids, lignans, iridoids.

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KEGG analysis showed EF treated hypertension through the MAPK and TNF signaling pathways.

Sodium-Glucose Cotransporter-2 Inhibitors in Vascular Biology: Cellular and Molecular Mechanisms

Sodium-glucose cotransporter-2 (SGLT2) inhibitors are new antidiabetic drugs that reduce hyperglycemia by inhibiting the glucose reabsorption in renal proximal tubules. Clinical studies have shown that SGLT2 inhibitors not only improve glycemic control but also reduce major adverse cardiovascular events (MACE, cardiovascular and total mortality, fatal or nonfatal myocardial infarction or stroke) and hospitalization for heart failure (HF), and improve outcome in chronic kidney disease. These cardiovascular and renal benefits have now been confirmed in both diabetes and non-diabetes patients. The precise mechanism(s) responsible for the protective effects are under intensive investigation. This review examines current evidence on the cardiovascular benefits of SGLT2 inhibitors, with a special emphasis on the vascular actions and their potential mechanisms.

Oxidative Stress, GTPCH1, and Endothelial Nitric Oxide Synthase Uncoupling in Hypertension

Significance: Hypertension has major health consequences, which is associated with endothelial dysfunction. Endothelial nitric oxide synthase (eNOS)-produced nitric oxide (NO) signaling in the vasculature plays an important role in maintaining vascular homeostasis. Considering the importance of NO system, this review aims to provide a brief overview of the biochemistry of members of NO signaling, including GTPCH1 [guanosine 5'-triphosphate (GTP) cyclohydrolase 1], tetrahydrobiopterin (BH4), and eNOS. Recent Advances: Being NO signaling activators and regulators of eNOS signaling, BH4 treatment is getting widespread attention either as potential therapeutic agents or as preventive agents. Recent clinical trials also support that BH4 treatment could be considered a promising therapeutic in hypertension. Critical Issues: Under conditions of BH4 depletion, eNOS-generated superoxides trigger pathological events. Abnormalities in NO availability and BH4 deficiency lead to disturbed redox regulation causing pathological events. This disturbed signaling influences the development of systemic hypertension as well as pulmonary hypertension. Future Directions: Considering the importance of BH4 and NO to improve the translational significance, it is essential to continue research on this field to manipulate BH4 to increase the efficacy for treating hypertension. Thus, this review also examines the current state of knowledge on the effects of eNOS activators on preclinical models and humans to utilize this information for potential therapy.

A Whole-Diet Approach Affects Not Only Fasting but Also Postprandial Cardiometabolic Risk Markers in Overweight and Obese Adults: A Randomized Controlled Trial

BACKGROUND

Current dietary recommendations for cardiovascular disease (CVD) prevention focus more on dietary patterns than on single nutrients. However, randomized controlled trials using whole-diet approaches to study effects on both fasting and postprandial CVD risk markers are limited.

OBJECTIVE

This randomized parallel trial compared the effects of a healthy diet (HD) with those of a typical Western diet (WD) on fasting and postprandial CVD risk markers in overweight and obese adults.

METHODS

After a 2-wk run-in period, 40 men and women (50-70 y; BMI: 25-35 kg/m2) consumed the HD (high in fruit and vegetables, pulses, fibers, nuts, fatty fish, polyunsaturated fatty acids; low in salt and high-glycemic carbohydrates; n = 19) or the WD (less fruit, vegetables, and fibers; no nuts and fatty fish; and more saturated fatty acids and simple carbohydrates; n = 21) for 6 wk. Fasting and postprandial cardiometabolic risk markers were assessed as secondary outcome parameters during a 5-h mixed-meal challenge, and a per protocol analysis was performed using 1-factor ANCOVA or linear mixed models.

RESULTS

Differences in diet-induced changes are expressed relative to the HD group. Changes in fasting plasma total cholesterol (-0.57 ± 0.12 mmol/L, P < 0.001), LDL cholesterol (-0.41 ± 0.12 mmol/L, P < 0.01), apolipoprotein B100 (-0.09 ± 0.03 g/L, P < 0.01), and apolipoprotein A1 (-0.06 ± 0.03 g/L, P = 0.05) were significantly different between the diet groups. Changes in postprandial plasma triacylglycerol (diet × time, P < 0.001) and apolipoprotein B48 (P < 0.01) differed significantly between the groups with clear improvements on the HD, although fasting triacylglycerols (-0.24 ± 0.13 mmol/L, P = 0.06) and apolipoprotein B48 (1.04 ± 0.67 mg/L, P = 0.40) did not. Significant differences between the diets were also detected in fasting systolic (-6.9 ± 3.1 mmHg, P < 0.05) and 24-h systolic (-5.0 ± 1.7 mmHg, P < 0.01) and diastolic (-3.3 ± 1.1 mmHg, P < 0.01) blood pressure.

CONCLUSION

A whole-diet approach targeted multiple fasting and postprandial CVD risk markers in overweight and obese adults. In fact, the postprandial measurements provided important additional information to estimate CVD risk. This trial is registered at clinicaltrials.gov as NCT02519127.

Effectiveness of dietary inorganic nitrate for lowering blood pressure in hypertensive adults: a systematic review

OBJECTIVE

The objective of this review was to evaluate the effectiveness of inorganic nitrate on blood pressure in hypertensive adults.

INTRODUCTION

Hypertension is associated with increased risk of morbidity and mortality in adults. Inorganic nitrate could be beneficial for lowering blood pressure and reducing cardiovascular disease risks. Evidence related to the treatment of hypertension through sources of inorganic nitrate has been presented.

INCLUSION CRITERIA

The review considered studies on adults aged 18 years and over, with blood pressure greater than 120/80 mmHg, undergoing interventions focusing on the effects of inorganic nitrate on blood pressure. Studies that included inorganic nitrate intake via dietary modification, in the form of a dietary supplement, and/or by the consumption of beetroot juice were considered. The comparator was no intervention of inorganic nitrate; different dosage, frequency, duration of inorganic nitrate; and other interventions that are administered to reduce and manage blood pressure. The primary outcomes were systolic and diastolic blood pressure effects. Experimental, quasi-experimental, analytical observational and pilot study designs were considered for inclusion.

METHODS

Databases were searched for published and unpublished studies, available in English, from January 2013 to January 2018. Critical appraisal was conducted using standardized instruments from the Joanna Briggs Institute (JBI) and the methodological quality of included studies was considered to be moderate. Data were extracted using the JBI data extraction instrument. Data were presented in a narrative form due to the heterogeneity of included studies.

RESULTS

Twelve papers were included in the systematic review with a total of 321 participants. Ten were randomized controlled trials and two were quasi-experimental studies. All participants had baseline blood pressures greater than 120/80 mmHg. Some studies included participants with comorbidities such as diabetes or heart failure with preserved ejection fraction. Inorganic nitrate was administered multiple ways throughout the studies including the following: beetroot juice, beetroot gel, nitric oxide lozenge, high nitrate diet, and raw and cooked beet juice. Doses and treatment intervals varied. Some studies included exercise as part of the intervention protocol.Meta-analysis was not conducted due to heterogeneity that existed within the studies. Blood pressure was measured in multiple settings by manual, digital or ambulatory means. The noted outcome patterns were as follows: no change in systolic blood pressure and diastolic blood pressure, decrease in systolic blood pressure and diastolic blood pressure, or decrease in systolic blood pressure with no change in diastolic blood pressure. Possible reasons for the diverse findings include the following: age, comorbidities, use of antihypertensives by participants; source and dose of nitrate; and intervention and follow-up time frames.

CONCLUSIONS

There is insufficient evidence to support or refute the use of inorganic nitrate for any effect on blood pressure at this time. Therefore, there is no concrete base for the development of practice guidelines until stronger evidence becomes available. The gaps in the literature along with the study limitations identified necessitate the need for more research on inorganic nitrate and how it relates to blood pressure.

A systemic review on the antioxidant and anti-inflammatory effects of resveratrol, curcumin, and dietary nitric oxide supplementation on human cardiovascular health

The potential benefits of supplemental nutrients and dietary interventions against cardiovascular morbidity and mortality have been extensively investigated throughout the years. Numerous supplements claim cardioprotection and reduction of cardiovascular risk factors, but the roles of many supplements have not been determined. In the vast number of supplements on the market asserting cardioprotective effects, only 3 have been thoroughly evaluated and consistently reported as effective by our clinic patients. They have used supplements such as fish oil, multivitamins, and calcium, but many had not known of the benefits of resveratrol, curcumin, and nitric oxide as supplements for improving cardiovascular health. The cardioprotective effects of these dietary supplements in both animal models and humans have been explored with proposed mechanisms of action mostly attributed to antioxidant and anti-inflammatory properties. Resveratrol is one of the most studied polyphenols with established cardiovascular benefits. Preclinical studies have demonstrated these effects exerted via improved inflammatory markers, atherogenic profile, glucose metabolism, and endothelial function and are further supported by clinical trials. Curcumin has a well-established anti-inflammatory role by regulating numerous transcription factors and cytokines linked to inflammation. Inflammation is an underlying pathology in cardiovascular diseases, rendering curcumin a potential therapeutic compound. Similarly, nitric oxide supplementation has demonstrated cardiovascular benefits by normalizing blood pressure; enhancing blood flow; and reducing inflammation, immune dysfunction, and oxidative stress. A comprehensive review was performed evaluating the cardioprotective effects of these 3 dietary supplements with hope to provide updated information, promote further awareness of these supplements, and inspire future studies on their effects on cardiovascular health.

Therapeutic Implications of Nitrite in Hypertension

Nitrite, an anion produced from the oxidative breakdown of nitric oxide (NO), has traditionally been viewed as an inert molecule. However, this dogma has been challenged with the findings that nitrite can be readily reduced to NO under pathological conditions, hence representing a physiologically relevant storage reservoir of NO either in the blood or tissues. Nitrite administration has been demonstrated to improve myocardial function in subjects with heart failure and to lower the blood pressure in hypertensive subjects. Thus, extensive amount of work has since been carried out to investigate the therapeutic potential of nitrite in treating cardiovascular diseases, especially hypertension. Studies done on several animal models of hypertension have demonstrated the efficacy of nitrite in preventing and ameliorating the pathological changes associated with the disease. This brief review of the current findings aims to re-evaluate the use of nitrite for the treatment of hypertension and in particular to highlight its role in improving endothelial function.

Associations of the NOS3 rs1799983 polymorphism with circulating nitric oxide and lipid levels: a systematic review and meta-analysis

BACKGROUND

Circulating nitric oxide (NO) and lipid levels are closely associated with coronary artery disease (CAD). It is unclear whether the rs1799983 polymorphism in endothelial nitric oxide synthase (NOS3) gene is associated with plasma levels of NO and lipids. This systematic review and meta-analysis (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) aimed to clarify the relationships between the rs1799983 polymorphism and plasma levels of NO and lipids.

METHODS

Sixteen studies (2702 subjects) and 59 studies (14 148 subjects) were identified for the association analyses for NO and lipids, respectively. Mean difference (MD) and 95% CI were used to estimate the effects of the rs1799983 polymorphism on plasma NO and lipid levels. The primary outcome variable was NO, and the secondary outcomes included triglycerides, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C).

RESULTS

Carriers of the T allele had lower levels of NO (MD -0.27 μmol/L, 95% CI -0.42 to -0.12 μmol/L, p<0.001) and HDL-C (MD -0.07 mmol/L, 95% CI -0.14 to -0.00 mmol/L, p=0.04), and higher levels of TC (MD 0.13 mmol/L, 95% CI 0.06 to 0.20 mmol/L, p<0.001) and LDL-C (MD 0.14 mmol/L, 95% CI 0.05 to 0.22 mmol/L, p=0.002) than the non-carriers. Triglyceride levels were comparable between the genotypes.

CONCLUSION

The association between the NOS3 rs1799983 polymorphism and CAD may be partly mediated by abnormal NO and lipid levels caused by the T allele.

Update on Gaseous Signaling Molecules Nitric Oxide and Hydrogen Sulfide: Strategies to Capture their Functional Activity for Human Therapeutics

Discovery of the production of gaseous molecules, such as nitric oxide and hydrogen sulfide, within the human body began a new concept in cellular signaling. Over the past 30 years, these molecules have been investigated and found to have extremely important beneficial effects in numerous chronic diseases. Gaseous signaling molecules that diffuse in three dimensions apparently contradict the selectivity and specificity afforded by normal ligand receptor binding and activation. This new concept has also created hurdles in the development of safe and efficacious drug therapy based on these molecules. Mechanisms involving formation of more stable intermediates and second messengers allow for new strategies for safe and effective delivery of these molecules for human disease. The purpose of this review is to highlight the biologic effects of nitric oxide and hydrogen sulfide, their seemingly indistinguishable effects, and how these molecules can be safely harnessed for drug development and precursors or substrates administered for human consumption through applied physiology.

Nutrients, Nutraceuticals, and Xenobiotics Affecting Renal Health

Chronic kidney disease (CKD) affects 8–16% of the population worldwide. In developed countries, the most important risk factors for CKD are diabetes, hypertension, and obesity, calling into question the importance of educating and acting on lifestyles and nutrition. A balanced diet and supplementation can indeed support the maintenance of a general health status, including preservation of renal function, and can help to manage and curb the main risk factors for renal damage. While the concept of protein and salt restriction in nephrology is historically acknowledged, the role of some nutrients in renal health and the importance of nutrition as a preventative measure for renal care are less known. In this narrative review, we provide an overview of the demonstrated and potential actions of some selected nutrients, nutraceuticals, and xenobiotics on renal health and function. The direct and indirect effects of fiber, protein, fatty acids, curcumin, steviol glycosides, green tea, coffee, nitrates, nitrites, and alcohol on kidney health are reviewed here. In view of functional and personalized nutrition, understanding the renal and systemic effects of dietary components is essential since many chronic conditions, including CKD, are related to systemic dysfunctions such as chronic low-grade inflammation.

Two angiotensin-converting enzyme-inhibitory peptides from almond protein and the protective action on vascular endothelial function

This study aimed to discover and prepare novel angiotensin converting enzyme (ACE) inhibitory peptides from almond protein and further evaluate the effect on endothelial function of human umbilical vascular endothelial cells (HUVECs). Almond protein was hydrolyzed using a two-stage alcalase-protamex hydrolysis process, and the hydrolysates were subjected to a series of separations, ultrafiltration, gel filtration chromatography, and reversed-phased preparative chromatography, to obtain the active peptides. Seven ACE inhibitory fractions with the molecular weight below 1.5 kDa were isolated and prepared, and two purified ACE inhibitory peptides with the IC50 values of 67.52 ± 0.05 and 43.18 ± 0.07 μg mL(-1), were identified as Met-His-Thr-Asp-Asp and Gln-His-Thr-Asp-Asp, respectively. Then the effect of two ACE inhibitory peptides on the endothelial function of HUVECs was evaluated. Results showed that the two potent ACE inhibitory peptides significantly regulated the release of nitric oxide and endothelin in HUVECs. These results suggest that almond peptides have potential as an antihypertensive nutraceuticals or a functional food ingredient.

Predictors of Calf Arterial Compliance in Male Veterans With Psychiatric Diagnoses

BACKGROUND

Peripheral arterial compliance (PAC) is a measure of the ability of the vascular tree to dilate in response to a pressure wave. Reduced PAC is seen in patients with psychiatric diagnoses and has been associated with increased risk for stroke, myocardial infarction, and mortality. The objective of this pilot study was to identify predictors of reduced PAC in subjects with psychiatric diagnoses.

METHODS

Male psychiatric subjects (N = 77) were studied in a cross-sectional study of medication effects on PAC conducted from August 2005 to February 2010. Calf and thigh compliance were modeled in separate linear regressions. The models were adjusted for age, race, smoking status, presence or absence of the metabolic syndrome, current treatment with a statin, diagnosis of schizophrenia or schizoaffective disorder, current antipsychotic treatment, and body mass index (BMI).

RESULTS

Of the 77 subjects (mean ± SD age of 53.7 ± 8.8 years), 41 were white, 36 were black, and 27 were diagnosed with schizophrenia or schizoaffective disorder (DSM-IV criteria). Fifty participants were being treated with an antipsychotic medication, while the remaining 27 were off of antipsychotics for at least 2 months. Our model explained 27% of the variance in calf compliance. Black subjects had reduced calf compliance compared to white subjects (P = .02). Having metabolic syndrome was associated with reduced PAC at a trend level (P < .08), and BMI (P = .004) and BMI² (P = .011) were significant predictors of calf compliance. Schizophrenia versus other psychiatric diagnoses and antipsychotic treatment were not significantly associated with calf compliance.

CONCLUSIONS

In this pilot study, significant predictors of calf compliance were race (black vs white) and BMI. PAC is a noninvasive measure that may be a predictor of cardiovascular risk in psychiatric patients. The reduced PAC seen in patients with psychiatric diagnoses does not appear to be directly related to their diagnosis or antipsychotic treatment but rather to other characteristics inherent to the subject. Future studies are warranted to better understand the pathophysiology of PAC including but not limited to inflammation in psychiatric patients.

Nitric oxide enhancement strategies

It is becoming increasingly clear that many diseases are characterized or associated with perturbations in nitric oxide (NO) production/signaling. Therapeutics or strategies designed to restore normal NO homeostasis will likely have broad application and utility. This highly complex and multistep pathway for NO production and subsequent target activation provides many steps in the endogenous pathway that may be useful targets for drug development for cardiovascular disease, antimicrobial, cancer, wound healing, etc. This article will summarize known strategies that are currently available or in development for enhancing NO production or availability in the human body. Each strategy will be discussed including exogenous sources of NO, use of precursors to promote NO production and downstream pathways affected by NO production with advantages and disadvantages highlighted for each. Development of NO-based therapeutics is and will continue to be a major focus of biotech, academia as well as pharmaceutical companies. Application of safe and effective strategies will certainly transform health and disease.