A Novel Method to Improve Perfusion of Ex Vivo Pumped Human Kidneys.

OBJECTIVE: To determine if addition of the S-nitrosylating agent ethyl nitrite (ENO) to the preservation solution can improve perfusion parameters in pumped human kidneys. BACKGROUND: A significant percentage of actively stored kidneys experience elevations in resistance and decreases in flow rate during the ex vivo storage period. Preclinical work indicates that renal status after brain death is negatively impacted by inflammation and reduced perfusion-processes regulated by protein S-nitrosylation. To translate these findings, we added ENO to the preservation solution in an attempt to reverse the perfusion deficits observed in nontransplanted pumped human kidneys. METHODS: After obtaining positive proof-of-concept results with swine kidneys, we studied donated human kidneys undergoing hypothermic pulsatile perfusion deemed unsuitable for transplantation. Control kidneys continued to be pumped a 4°C (ie, standard of care). In the experimental group, the preservation solution was aerated with 50 ppm ENO in nitrogen. Flow rate and perfusion were recorded for 10 hours followed by biochemical analysis of the kidney tissue. RESULTS: In controls, perfusion was constant during the monitoring period (ie, flow rate remained low and resistance stayed high). In contrast, the addition of ENO produced significant and sustained reductions in resistance and increases in flow rate. ENO-treated kidneys had higher levels of cyclic guanosine monophosphate, potentially explaining the perfusion benefits, and increased levels of interleukin-10, suggestive of an anti-inflammatory effect. CONCLUSIONS: S-Nitrosylation therapy restored the microcirculation and thus improved overall organ perfusion. Inclusion of ENO in the renal preservation solution holds promise to increase the number and quality of kidneys available for transplant.

Nitrate-nitrite exposure through drinking water and diet and risk of colorectal cancer: A systematic review and meta-analysis of observational studies.

BACKGROUND: Considerable controversy exists regarding the association between nitrate intake and risk of colorectal cancer. Therefore, we performed a dose-response meta-analysis of observational studies. METHODS: We identified relevant studies by searching PubMed, Scopus and ISI Web of Knowledge until April 2020 and references of retrieved relevant articles. The random-effects model was used to calculate pooled effect size (ESs) and 95% confidence intervals (CIs). RESULTS: Fifteen prospective cohort and case-control papers were included in this systematic review and meta-analysis. In total, 2,573,524 participants with an age range between 20 and 85 years were included. The total number of colorectal cancer cases was 38,848. Intake of nitrate from diet was associated with a risk of colorectal cancer (Pooled HR: 1.13; 95% CI: 1.04-1.23, I2 = 38%; P = 0.08). Nitrite in diet was not significantly associated with risk of colorectal cancer (pooled HR: 1.07; 95% CI: 0.95-1.21, I2 = 61.6%; P = 0.005). Nitrate in water did not show an association with risk of colorectal cancer (pooled HR: 1.04; 95% CI: 0.92-1.19, I2 = 64.7%; P = 0.002). Non-linear dose-response analysis revealed no significant association of dietary nitrite and also nitrate of drinking water with risk of colorectal cancer. However, dietary nitrate was marginally associated with a greater risk of colorectal cancer. Linear dose-response analysis of nitrate from diet was not associated with colorectal cancer risk by an additional 50 mg per day. Such a non-significant association was also seen for colorectal cancer risk by an additional 1 mg per day and 1 mg/l from dietary nitrite and water nitrate respectively. CONCLUSIONS: Dietary nitrate was related to a higher risk of colorectal cancer risk. However, intake of nitrite from diet and nitrate from the drinking water was not associated with colorectal cancer risk.

Risk assessment of nitrites for the Austrian adult population with probabilistic modelling of the dietary exposure.

Nitrites are present in the food chain as naturally occurring species or contaminants. Additionally, sodium and potassium nitrites are authorised food additives. Nitrites exert acute toxicity through methemoglobinemia or cardiovascular effects, chronic toxicity associated with endocrine, reproductive and developmental effects and have been classified as probable gastric carcinogens. Ingestion of food and water are the main sources of human exposure. This study comprises a tiered risk assessment of nitrites for the Austrian adult population, along with the identification of the food categories most contributing to their intake. The dietary exposure, based on Austrian occurrence and consumption data, was modelled with the Monte Carlo simulation method. In an additional scenario, data gaps were addressed with the usage of occurrence data published by the European Food Safety Authority and from the available literature to account for the exposure from all sources. Risk estimates regarding only the exposure to nitrite additives and to contaminated water indicate low level of concern. However, when exposure from all sources is considered, the estimated exposure is elevated and exceeds the Acceptable Daily Intake for high consumers. Mean exposure attributed to the use of nitrites as additives accounts for only a very small proportion of the total intake.

The relationship between consumption of nitrite or nitrate and risk of non-Hodgkin lymphoma.

Epidemiologic studies of the relationship between nitrite or nitrate consumption and risk of non-Hodgkin lymphoma (NHL) remain controversial. The current meta-analysis aimed to reexamine the evidence and quantitatively evaluate that relationship. Manuscripts were retrieved from the Web of Science, Chinese National Knowledge Infrastructure and PubMed databases up to May 2019. From the studies included in the review, results were combined and presented as odds ratios (OR). To conduct a dose-response (DR) analysis, studies presenting risk estimates over a series of categories of exposure were selected. Our data indicate that the consumption of nitrite was linked to a significantly increased hazard of NHL (OR: 1.37; 95% CI: 1.14-1.65), rather than nitrate (OR: 1.02; 95% CI: 0.94-1.10). According to Egger's and Begg's tests (P > 0.05), there was no evidence of significant publication bias. Moreover, our DR analysis indicated that the risk of NHL grew by 26% for each additional microgram of nitrite consumed in the diet per day (OR: 1.26; 95% CI: 1.09-1.42). Through subset analysis of the nitrite studies, data from the high-quality studies indicated that consumption was positively associated with carcinogenicity, leading to NHL (OR: 1.44; 95% CI: 1.17-1.77) and positively correlated with the development of diffuse large B-cell lymphoma (OR: 1.55; 95% CI: 1.07-2.26), but not other NHL subtypes. In addition, the data suggested that females (OR: 1.50; 95% CI: 1.15-1.95) and high levels of nitrite intake (OR: 1.64; 95% CI: 1.28-2.09) had a higher risk of NHL. Our meta-analysis supports the hypothesis that nitrite intake, but not that of nitrate, raises the risk of developing NHL. In the future, better designed prospective research studies should be conducted to confirm our findings, clarify potential biological mechanisms and instruct clinicians about NHL prophylaxis.

Pulmonary Vasodilation by Intravenous Infusion of Organic Mononitrites Of 1,2-Propanediol in Acute Pulmonary Hypertension Induced by Aortic Cross Clamping and Reperfusion: A Comparison With Nitroglycerin in Anesthetized Pigs.

INTRODUCTION: Suprarenal aortic cross clamping (SRACC) and reperfusion may cause acute pulmonary hypertension and multiple organ failure. HYPOTHESIS: The organic mononitrites of 1,2-propanediol (PDNO), an nitric oxide donor with a very short half-life, are a more efficient pulmonary vasodilator and attenuator of end-organ damage and inflammation without significant side effects compared with nitroglycerin and inorganic nitrite in a porcine SRACC model. METHODS: Anesthetized and instrumented domestic pigs were randomized to either of four IV infusions until the end of the experiment (n = 10 per group): saline (control), PDNO (45 nmol kg min), nitroglycerin (44 nmol kg min), or inorganic nitrite (a dose corresponding to PDNO). Thereafter, all animals were subjected to 90 min of SRACC and 10 h of reperfusion and protocolized resuscitation. Hemodynamic and respiratory variables as well as blood samples were collected and analysed. RESULTS: During reperfusion, mean pulmonary arterial pressure and pulmonary vascular resistance were significantly lower, and stroke volume was significantly higher in the PDNO group compared with the control, nitroglycerin, and inorganic nitrite groups. In parallel, mean arterial pressure, arterial oxygenation, and fraction of methaemoglobin were similar in all groups. The serum concentration of creatinine and tumor necrosis factor alpha were lower in the PDNO group compared with the control group during reperfusion. CONCLUSIONS: PDNO was an effective pulmonary vasodilator and appeared superior to nitroglycerin and inorganic nitrite, without causing significant systemic hypotension, impaired arterial oxygenation, or methaemoglobin formation in an animal model of SRACC and reperfusion. Also, PDNO may have kidney-protective effects and anti-inflammatory properties.

Inorganic nitrate and nitrite supplementation fails to improve skeletal muscle mitochondrial efficiency in mice and humans.

BACKGROUND: Inorganic nitrate, abundant in leafy green vegetables and beetroot, is thought to have protective health benefits. Adherence to a Mediterranean diet reduces the incidence and severity of coronary artery disease, whereas supplementation with nitrate can improve submaximal exercise performance. Once ingested, oral commensal bacteria may reduce nitrate to nitrite, which may subsequently be reduced to nitric oxide during conditions of hypoxia and in the presence of "nitrite reductases" such as heme- and molybdenum-containing enzymes. OBJECTIVE: We aimed to explore the putative effects of inorganic nitrate and nitrite on mitochondrial function in skeletal muscle. METHODS: Mice were subjected to a nitrate/nitrite-depleted diet for 2 wk, then supplemented with sodium nitrate, sodium nitrite, or sodium chloride (1 g/L) in drinking water ad libitum for 7 d before killing. Skeletal muscle mitochondrial function and expression of uncoupling protein (UCP) 3, ADP/ATP carrier protein (AAC) 1 and AAC2, and pyruvate dehydrogenase (PDH) were assessed by respirometry and Western blotting. Studies were also undertaken in human skeletal muscle biopsies from a cohort of coronary artery bypass graft patients treated with either sodium nitrite (30-min infusion of 10 µmol/min) or vehicle [0.9% (wt:vol) saline] 24 h before surgery. RESULTS: Neither sodium nitrate nor sodium nitrite supplementation altered mitochondrial coupling efficiency in murine skeletal muscle, and expression of UCP3, AAC1, or AAC2, and PDH phosphorylation status did not differ between the nitrite and saline groups. Similar results were observed in human samples. CONCLUSIONS: Sodium nitrite failed to improve mitochondrial metabolic efficiency, rendering this mechanism implausible for the purported exercise benefits of dietary nitrate supplementation. This trial was registered at clinicaltrials.gov as NCT04001283.

Análise do perfil de textura de apresuntados elaborados com diferentes concentrações de nitrito / Texture profile analysis of restructured cooked ham elaborated with different nitrite contents

O trabalho objetivou estudar os efeitos da adição de diferentes concentrações de nitrito (0 a 300 mg/Kg) nos atributos de textura de apresuntados ao decorrer do tempo de armazenamento a vácuo (0 a 40 dias) utilizando um delineamento composto central rotacional. Maiores perdas de peso por cozimento foram observadas (P0,05) pelos fatores estudados, enquanto que maiores valores de flexibilidade foram observados nos produtos adicionados de maior quantidade de nitrito. Concluiu-se que o perfil de textura de produtos cárneos cozidos é ligeiramente alterado pela adição de nitrito de sódio.

Efeito da adição de nitrito nos valores de nitrito residual e cor de apresuntados durante o armazenamento / Effect of nitrite addition on residual nitrite values and color of reestructured cooked ham during storage

Objetivou-se avaliar a cinética de redução das concentrações de nitrito adicionado (0 a 300 mg/kg) em apresuntados e seus efeitos na cor curada ao decorrer do tempo de armazenamento a vácuo (0 a 40 dias). O teor de nitrito residual aumentou (P0,05) por nenhum dos fatores. O comportamento para a tonalidade (h) foi o inverso do índice de cor curada, sendo que pequenas adições de nitrito implicaram em uma cor mais avermelhada (mais rosada), com ligeira perda (fading) no decorrer do tempo de armazenamento. Adições de 50 a 300 mg/kg de nitrito basicamente não alteraram a cor dos produtos, sendo pouco afetado pelo tempo de armazenamento à vácuo.

AMP-activated protein kinase activation and NADPH oxidase inhibition by inorganic nitrate and nitrite prevent liver steatosis.

Advanced age and unhealthy dietary habits contribute to the increasing incidence of obesity and type 2 diabetes. These metabolic disorders, which are often accompanied by oxidative stress and compromised nitric oxide (NO) signaling, increase the risk of adverse cardiovascular complications and development of fatty liver disease. Here, we investigated the therapeutic effects of dietary nitrate, which is found in high levels in green leafy vegetables, on liver steatosis associated with metabolic syndrome. Dietary nitrate fuels a nitrate-nitrite-NO signaling pathway, which prevented many features of metabolic syndrome and liver steatosis that developed in mice fed a high-fat diet, with or without combination with an inhibitor of NOS (l-NAME). These favorable effects of nitrate were absent in germ-free mice, demonstrating the central importance of host microbiota in bioactivation of nitrate. In a human liver cell line (HepG2) and in a validated hepatic 3D model with primary human hepatocyte spheroids, nitrite treatment reduced the degree of metabolically induced steatosis (i.e., high glucose, insulin, and free fatty acids), as well as drug-induced steatosis (i.e., amiodarone). Mechanistically, the salutary metabolic effects of nitrate and nitrite can be ascribed to nitrite-derived formation of NO species and activation of soluble guanylyl cyclase, where xanthine oxidoreductase is proposed to mediate the reduction of nitrite. Boosting this nitrate-nitrite-NO pathway results in attenuation of NADPH oxidase-derived oxidative stress and stimulation of AMP-activated protein kinase and downstream signaling pathways regulating lipogenesis, fatty acid oxidation, and glucose homeostasis. These findings may have implications for novel nutrition-based preventive and therapeutic strategies against liver steatosis associated with metabolic dysfunction.

Determination of dietary nitrite in patients with esophageal pre-cancerous lesion and normal people: a duplicate diet study.

The goal of this study was to find the relationship between dietary nitrite and risk of esophageal cancer, and determine the amount of nitrite intake to establish the oral highest daily intake to prevent the occurrence of esophageal cancer. Duplicate portions of three-consecutive-day diets were collected from 100 patients with esophageal precancerous lesions and 100 controls. The average nitrite daily intakes for esophageal precancerous lesions and normal people were 15.72 mg/d and 11.11 mg/d. The median nitrite daily intakes for cases and controls were 8.76 mg/d and 5.33 mg/d. Positive association was observed between the risk of esophageal precancerous lesions and dietary nitrite intake (p = 0.035). An increased risk of esophageal precancerous lesions was observed for cases or controls in the highest intake quartile of nitrite (highest vs. lowest quartile odds ratio (OR) = 2.256, 95% confidence interval (CI): 1.012-5.026). These results suggest that dietary nitrite intake may influence the risk of esophageal cancer; populations with high incidence of esophageal cancer should take control of nitrite intake as one of the measures to prevent esophageal cancer.

To what extent does the nitrosation of meat proteins influence their digestibility?

Nitrosation can occur during meat digestion due to the physicochemical conditions of the stomach (low pH and reducing conditions). The aim of the present study was to elucidate the link between the nitrosation of proteins from beef meat and their digestibility by comparing cooked meat digested with and without the addition of nitrite. To do this, a dynamic in vitro artificial digestive computer-controlled system (DIDGI®) was used to reflect human gastro-intestinal conditions. Peptides and proteins from gastrointestinal digestion were identified by high-resolution LC-MS/MS mass spectrometry. The results showed a dynamic digestion pattern of meat proteins according to their cellular localization. A combined effect of the digestive compartment and the addition of nitrite was established for the first time on peptides profile, linking the nitrosation of proteins and their digestibility.

Actualización en abuso de drogas por vía nasal / Update on drug abuse by nasal route

La vía nasal, ya sea mediante la inhalación o aspiración, se ha convertido en una ruta atractiva para quienes abusan de sustancias, principalmente por la fácil accesibilidad y la rápida absorción sistémica, además de evitar las consecuencias asociadas al uso de drogas intravenosas (enfermedades de transmisión). El objetivo de esta revisión es presentar una actualización de diversas sustancias que son utilizadas por esta vía, enfocándose en aquellas en las que se ha documentado daños en la anatomía nasal.

The nasal route, either by inhalation or aspiration, has become an attractive route for substances abusers, mainly because of its easy accessibility, rapid systemic absorption and also to avoid the consequences associated with intravenous drug use (transmitted diseases). The objective of this review is to present an update of various substances that are used by this route, focusing on those in which damage to the nasal anatomy has been documented.

X-Ray responsive nanoparticles with triggered release of nitrite, a precursor of reactive nitrogen species, for enhanced cancer radiosensitization.

Remotely and locally triggered release of therapeutic species by X-ray irradiation is highly desired to enhance the efficacy of radiotherapy. However, the development of such X-ray responsive nanosystems remains a challenge, especially in response to high energy clinically relevant X-ray radiation. Herein, we report novel nitroimidazole ligated gold nanoparticles (AuNPs) that synergistically function to release nitrite, an important precursor for nitric oxide and reactive nitrogen species that sensitize cancer cells, upon radiation with clinically used 6 MeV X-rays, while no release was detected without radiation. These functional AuNPs were prepared with surface-grafted nitroimidazole as the nitrite-releasing agent, cell-penetrating peptide (CPP) to induce nucleus localization, and poly(ethylene glycol) for water solubility. In vitro radiotherapy using such nanoparticles showed enhanced sensitivity of hypoxic cancer cells to X-ray radiation, presumably due to the generation of both reactive oxygen and nitrogen species. The dose modifying factor (DMF) was found to be 0.71 for the dual-functionalized nanoparticle, which indicates that significant lower X-ray doses are required to achieve the same therapeutic effects. Thus, X-ray triggered nitrite release from gold-nitroimidazole nanosystems offers a novel strategy to sensitize cancer cells for improved radiotherapy.

S-nitrosation of calpains is associated with cardioprotection in myocardial I/R injury.

BACKGROUND: Myocardial infarction remains the single leading cause of death worldwide. Upon reperfusion of occluded arteries, deleterious cellular mediators particularly located at the mitochondria level can be activated, thus limiting the outcome in patients. This may lead to the so-called ischemia/reperfusion (I/R) injury. Calpains are cysteine proteases and mediators of caspase-independent cell death. Recently, they have emerged as central transmitters of cellular injury in several cardiac pathologies e.g. hypertrophy and acute I/R injury. METHODS: Here we investigated the role of cardiac calpains in acute I/R in relation to mitochondrial integrity and whether calpains can be effectively inhibited by posttranslational modification by S-nitrosation. Taking advantage of the a cardiomyocyte cell line (HL1), we determined S-nitrosation by the Biotin-switch approach, cell viability and intracellular calcium concentration after simulated ischemia and reoxygenation - all in dependence of supplementation with nitrite, which is known as an 'hypoxic nitric oxide (NO) donor'. Likewise, using an in vivo I/R model, calpain S-nitrosation, calpain activity and myocardial I/R injury were characterized in vivo. RESULTS: Nitrite administration resulted in an increased S-nitrosation of calpains, and this was associated with an improved cell-survival. No impact was detected on calcium levels. In line with these in vitro experiments, nitrite initiated calpain S-nitrosation in vivo and caused an infarct sparing effect in an in vivo myocardial I/R model. Using electron microscopy in combination with immuno-gold labeling we determined that calpain 10 increased, while calpain 2 decreased in the course of I/R. Nitrite, in turn, prevented an I/R induced increase of calpains 10 at mitochondria and reduced levels of calpain 1. CONCLUSION: Lethal myocardial injury remains a key aspect of myocardial I/R. We show that calpains, as key players in caspase-independent apoptosis, increasingly locate at mitochondria following I/R. Inhibitory post-translational modification by S-nitrosation of calpains reduces deleterious calpain activity in murine cardiomyocytes and in vivo.

Dietary nitrite reverses features of postmenopausal metabolic syndrome induced by high-fat diet and ovariectomy in mice.

Menopausal women are at greater risk of developing metabolic syndrome with reduced endothelial nitric oxide synthase (eNOS) activity. Hormone replacement therapy increases eNOS activity and normalizes some characteristics of metabolic syndrome. We hypothesized that nitric oxide (NO) supplementation should have a therapeutic effect on this syndrome. We examined the effect of dietary nitrite in a mouse model with postmenopausal metabolic syndrome induced by ovariectomy (OVX) and a high fat diet (HF). C57BL/6 female mice were divided into five groups, sham+normal fat diet (NF), sham+ HF, OVX+HF with or without sodium nitrite (50 mg and 150 mg/l) in the drinking water. Daily food intake and weekly body weight were monitored for 18 wk. OVX and HF significantly reduced plasma levels of nitrate/nitrite (NOx), and mice developed obesity with visceral hypertrophic adipocytes and increased transcriptional levels of monocyte chemoattractant protein-1, TNF-α, and IL-6 in visceral fat tissues. The proinflammatory state in the adipocytes provoked severe hepatosteatosis and insulin resistance in OVX+HF group compared with sham+NF group. However, dietary nitrite significantly suppressed adipocyte hypertrophy and transcriptions of proinflammatory cytokines in visceral fat in a dose-dependent manner. The improvement of visceral inflammatory state consequently reversed the hepatosteatosis and insulin resistance observed in OVX+HF mice. These results suggest that an endogenous NO defect might underlie postmenopausal metabolic syndrome and that dietary nitrite provides an alternative source of NO, subsequently compensating for metabolic impairments of this syndrome.

Nitrite therapy prevents chlorine gas toxicity in rabbits.

Chlorine (Cl2) gas exposure and toxicity remains a concern in military and industrial sectors. While post-Cl2 exposure damage to the lungs and other tissues has been documented and major underlying mechanisms elucidated, no targeted therapeutics that are effective when administered post-exposure, and which are amenable to mass-casualty scenarios have been developed. Our recent studies show nitrite administered by intramuscular (IM) injection post-Cl2 exposure is effective in preventing acute lung injury and improving survival in rodent models. Our goal in this study was to develop a rabbit model of Cl2 toxicity and test whether nitrite affords protection in a non-rodent model. Exposure of New Zealand White rabbits to Cl2 gas (600ppm, 45min) caused significant increases in protein and neutrophil accumulation in the airways and ∼35% mortality over 18h. Nitrite administered 30min post Cl2 exposure by a single IM injection, at 1mg/kg or 10mg/kg, prevented indices of acute lung injury at 6h by up to 50%. Moreover, all rabbits that received nitrite survived over the study period. These data provide further rationale for developing nitrite as post-exposure therapeutic to mitigate against Cl2 gas exposure injury.

Effects of nitrate supplementation in trained and untrained muscle are modest with initial high plasma nitrite levels.

Nitrate (NO3-) supplementation resulting in higher plasma nitrite (NO2-) is reported to lower resting mean arterial blood pressure (MAP) and oxygen uptake (VO2 ) during submaximal exercise in non-athletic populations, whereas effects in general are absent in endurance-trained individuals. To test whether physiologic effects of NO3- supplementation depend on local muscular training status or cardiovascular fitness, male endurance-trained cyclists (CYC, n=9, VO2 -max: 64±3 mL/min/kg; mean±SD) and recreational active subjects serving as a control group (CON, n=8, 46±3 mL/min/kg), acutely consumed nitrate-rich beetroot juice ([NO3-] ~9 mmol) (NIT) or placebo (PLA) with assessment of resting MAP and energy expenditure during moderate intensity (~50% VO2 -max) and incremental leg cycling (LEG-ex) and arm-cranking exercise (ARM-ex). NIT increased (P<.001) resting plasma NO3- by ~1200% relative to PLA. Plasma NO2- increased ~25% (P<.01) with a significant change only in CYC. LEG-ex VO2 (~2.60 L/min), ARM-ex VO2 (~1.14 L/min), and resting MAP (~87 mm Hg) remained unchanged for CYC, and similarly for CON, no changes were observed for LEG-ex VO2 (~2.03 L/min), ARM-ex VO2 (~1.06 L/min), or resting MAP (~85 mm Hg). VO2 -max was not affected by supplementation, but incremental test peak power was higher (P<.05) in LEG-ex for CYC in NIT relative to PLA (418±47 vs 407±46 W). In both CYC and CON, high initial baseline values and small increases in plasma NO2- after NIT may have lowered the effect of the intervention implying that muscular and cardiovascular training status is likely not the only factors that influence the physiologic effects of NO3- supplementation.

Consumption of a flavonoid-rich açai meal is associated with acute improvements in vascular function and a reduction in total oxidative status in healthy overweight men.

BACKGROUND: Açai (Euterpe oleracea) is a polyphenol-rich fruit marketed as beneficial for health. Experimental data showing improvements in health markers arising from açai consumption in humans is limited. OBJECTIVE: The objective of the present study was to investigate the effect of açai consumption on acute changes in vascular function and on other disease risk markers, including postprandial plasma insulin, glucose, and oxidative stress. DESIGN: Twenty-three healthy male volunteers, aged 30-65 y and with a body mass index (in kg/m2) of 25-30, completed a randomized, controlled, high-fat challenge, double-blind, crossover, acute dietary intervention trial. The volunteers consumed either an açai-based smoothie (AS) or a macronutrient-matched control smoothie (PS) together with a high-fat breakfast meal challenge. The primary endpoint was the assessment of endothelial function in the brachial artery by flow-mediated dilatation (FMD). RESULTS: The acute consumption of an AS containing 694 mg total phenolics improved vascular function, with postprandial increases in FMD from baseline of 1.4% at 2 h compared with 0.4% after consumption of the PS (P = 0.001) and increases at 6 h of 0.8% for the AS compared with -0.3% for the PS (P < 0.001). There was also a significantly lower incremental area under the curve (iAUC) for total peroxide oxidative status after açai consumption relative to the control. No significant changes were observed in blood pressure, heart rate, or postprandial glucose response. However, the first postprandial insulin peak (after breakfast) and the iAUC for insulin were elevated for the AS relative to the PS. CONCLUSIONS: In this acute study in overweight men, açai consumption was associated with improvements in vascular function, which may lower the risk of a cardiovascular event. Future intervention studies, perhaps with a chronic design, in wider populations and with other biomarkers of disease risk are needed to fully elucidate the benefits of açai to health. This trial was registered at clinicaltrials.gov as NCT02292329.

NO-Rich Diet for Lifestyle-Related Diseases.

Decreased nitric oxide (NO) availability due to obesity and endothelial dysfunction might be causally related to the development of lifestyle-related diseases such as insulin resistance, ischemic heart disease, and hypertension. In such situations, instead of impaired NO synthase (NOS)-dependent NO generation, the entero-salivary nitrate-nitrite-NO pathway might serve as a backup system for NO generation by transmitting NO activities in the various molecular forms including NO and protein S-nitrosothiols. Recently accumulated evidence has demonstrated that dietary intake of fruits and vegetables rich in nitrate/nitrite is an inexpensive and easily-practicable way to prevent insulin resistance and vascular endothelial dysfunction by increasing the NO availability; a NO-rich diet may also prevent other lifestyle-related diseases, including osteoporosis, chronic obstructive pulmonary disease (COPD), and cancer. This review provides an overview of our current knowledge of NO generation through the entero-salivary pathway and discusses its safety and preventive effects on lifestyle-related diseases.

Effects of hemin and nitrite on intestinal tumorigenesis in the A/J Min/+ mouse model.

Red and processed meats are considered risk factors for colorectal cancer (CRC); however, the underlying mechanisms are still unclear. One cause for the potential link between CRC and meat is the heme iron in red meat. Two pathways by which heme and CRC promotion may be linked have been suggested: fat peroxidation and N-nitrosation. In the present work we have used the novel A/J Min/+ mouse model to test the effects of dietary hemin (a model of red meat), and hemin in combination with nitrite (a model of processed meat) on intestinal tumorigenesis. Mice were fed a low Ca2+ and vitamin D semi-synthetic diet with added hemin and/or nitrite for 8 weeks post weaning, before termination followed by excision and examination of the intestinal tract. Our results indicate that dietary hemin decreased the number of colonic lesions in the A/J Min/+ mouse. However, our results also showed that the opposite occurred in the small intestine, where dietary hemin appeared to stimulate tumor growth. Furthermore, we find that nitrite, which did not have an effect in the colon, appeared to have a suppressive effect on tumor growth in the small intestine.