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Curry BH, Bond V, Pemminati S, Gorantla VR, Volkova YA, Kadur K, Millis RM. Effects of a Dietary Beetroot Juice Treatment on Systemic and Cerebral Haemodynamics- A Pilot Study. J Clin Diagn Res 2016; 10:CC01-5. [PMID: 27630836 DOI: 10.7860/jcdr/2016/20049.8113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 06/07/2016] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Beetroot Juice (BJ) contains dietary nitrates that increase the blood Nitric Oxide (NO) level, decrease Blood Pressure (BP), increase athletic performance and improve cognitive functions but the mechanism remains unclear. Ultrasonographic measurement of middle cerebral artery blood flow velocity with computation of Cerebral Augmentation Index (CAIx) is a measure of the reflected flow signal, modulated by changes in cerebrovascular resistance and compliance. AIM This pilot study tests the hypothesis that ingestion of an amount of BJ sufficient to raise the blood NO level two-to three-fold, decreases Transcranial Doppler (TCD) measured CAIx. MATERIALS AND METHODS Ten healthy young-adult African-American women were studied at two levels of submaximal exercise, 40% and 80% of their predetermined peak oxygen consumptions. The subjects ingested nitrate-free orange juice (OJ, control) and an isocaloric BJ beverage (1.5 mg/mL nitrate, 220 Cal), on different days, 1-2 weeks apart. RESULTS The BJ treatment increased blood NO and decreased systolic BP at rest and at the two levels of exercise. The BJ treatment decreased CAIx only at the two levels of exercise (from 79 ± 2% to 62 ± 2% and from 80 ± 2% to 60 ± 3%, p<0.05). Exercise increased TCD-measured resistance and pulsatility indices (RIx, PIx) without changing AIx. The BJ treatment had no effect on RIx and PIx. CONCLUSION These findings suggest that decreased CAIx associated with aerobic exercise reflects the change in cerebral haemodynamics resulting from dietary nitrate supplementation. Future studies should determine whether the BJ-induced decrement in CAIx is correlated with an improvement in brain function.
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Affiliation(s)
- Bryan Heath Curry
- Professor, Department of Medicine, Division of Cardiology, Howard University College of Medicine and Howard University Hospital , Washington, DC 20060, United States of America
| | - Vernon Bond
- Professor, Department of Recreation, Human Performance and Leisure Studies and Exercise Science and Human Nutrition Laboratory, Howard University Cancer Centre , Washington, DC 20060, United States of America
| | - Sudhakar Pemminati
- Associate Professor, Department of Medical Pharmacology, AUA College of Medicine and Manipal University , Antigua
| | - Vasavi Rakesh Gorantla
- Assistant Professor, Department of Behavioural Sciences and Neuroscience, AUA College of Medicine , Antigua
| | | | - Kishan Kadur
- Assistant Professor, Department of Medical Physiology, AUA College of Medicine , Antigua
| | - Richard Mark Millis
- Professor, Department of Medical Physiology, AUA College of Medicine , Antigua
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102
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Wajih N, Liu X, Shetty P, Basu S, Wu H, Hogg N, Patel RP, Furdui CM, Kim-Shapiro DB. The role of red blood cell S-nitrosation in nitrite bioactivation and its modulation by leucine and glucose. Redox Biol 2016; 8:415-21. [PMID: 27156251 PMCID: PMC4864376 DOI: 10.1016/j.redox.2016.04.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 04/27/2016] [Accepted: 04/29/2016] [Indexed: 02/07/2023] Open
Abstract
Previous work has shown that red blood cells (RBCs) reduce nitrite to NO under conditions of low oxygen. Strong support for the ability of red blood cells to promote nitrite bioactivation comes from using platelet activation as a NO-sensitive process. Whereas addition of nitrite to platelet rich plasma in the absence of RBCs has no effect on inhibition of platelet activation, when RBCs are present platelet activation is inhibited by an NO-dependent mechanism that is potentiated under hypoxia. In this paper, we demonstrate that nitrite bioactivation by RBCs is blunted by physiologically-relevant concentrations of nutrients including glucose and the important signaling amino acid leucine. Our mechanistic investigations demonstrate that RBC mediated nitrite bioactivation is largely dependent on nitrosation of RBC surface proteins. These data suggest a new expanded paradigm where RBC mediated nitrite bioactivation not only directs blood flow to areas of low oxygen but also to areas of low nutrients. Our findings could have profound implications for normal physiology as well as pathophysiology in a variety of diseases including diabetes, sickle cell disease, and arteriosclerosis.
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Affiliation(s)
- Nadeem Wajih
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Xiaohua Liu
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Pragna Shetty
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Swati Basu
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, USA; Translational Science Center, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Hanzhi Wu
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Neil Hogg
- Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Rakesh P Patel
- Department of Pathology, University of Alabama at Birmingham, 901 19th St. South, BMRII 532, Birmingham, AL 35294, USA
| | - Cristina M Furdui
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Daniel B Kim-Shapiro
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, USA; Translational Science Center, Wake Forest University, Winston-Salem, NC 27109, USA.
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103
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Oliveira-Paula GH, Pinheiro LC, Guimaraes DA, Tella SOC, Blanco ALF, Angelis CD, Schechter AN, Tanus-Santos JE. Tempol improves xanthine oxidoreductase-mediated vascular responses to nitrite in experimental renovascular hypertension. Redox Biol 2016; 8:398-406. [PMID: 27078869 PMCID: PMC5022046 DOI: 10.1016/j.redox.2016.04.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 03/30/2016] [Accepted: 04/04/2016] [Indexed: 02/07/2023] Open
Abstract
Upregulation of xanthine oxidoreductase (XOR) increases vascular reactive oxygen species (ROS) levels and contributes to nitroso-redox imbalance. However, XOR can generate nitric oxide (NO) from nitrite, and increased superoxide could inactivate NO formed from nitrite. This study tested the hypothesis that XOR contributes to the cardiovascular effects of nitrite in renovascular hypertension, and that treatment with the antioxidant tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl) improves XOR-mediated effects of nitrite. Blood pressure was assessed weekly in two-kidney one-clip (2K1C) and control rats. After six weeks of hypertension, the relaxing responses to nitrite were assessed in aortic rings in the presence of the XOR inhibitor oxypurinol (or vehicle), either in the absence or in the presence of tempol. Moreover, in vivo hypotensive responses to nitrite were also examined in the presence of oxypurinol (or vehicle) and tempol (or vehicle). Aortic XOR activity and expression were evaluated by fluorescence and Western blot, respectively. Vascular ROS production was assessed by the dihydroethidium assay. 2K1C hypertensive rats showed increased aortic XOR activity and vascular ROS production compared with control rats. Oxypurinol shifted the nitrite concentration–response curve to the right in aortic rings from 2K1C rats (but not in controls). Oxypurinol also attenuated the hypotensive responses to nitrite in 2K1C rats (but not in controls). These functional findings agree with increased aortic and plasma XOR activity found in 2K1C rats. Tempol treatment enhanced oxypurinol-induced shift of the nitrite concentration–response curve to the right. However, antioxidant treatment did not affect XOR-mediated hypotensive effects of nitrite. Our results show that XOR is important to the cardiovascular responses to nitrite in 2K1C hypertension, and XOR inhibitors commonly used by patients may cancel this effect. This finding suggests that nitrite treatment may not be effective in patients being treated with XOR inhibitors. Moreover, while tempol may improve the vascular responses to nitrite, antihypertensive responses are not affected. Upregulation of xanthine oxidoreductase (XOR) is usually found in hypertension. While XOR produces superoxide, it can also produce NO from nitrite. This study shows that XOR mediates vasorelaxing effects of nitrite in renovascular hypertension. XOR inhibition prevents against the antihypertensive effects of nitrite. Antioxidant treatment improves XOR-mediated vasorelaxing effects of nitrite.
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Affiliation(s)
- Gustavo H Oliveira-Paula
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Lucas C Pinheiro
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Danielle A Guimaraes
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Sandra O Conde Tella
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Ana L Furlan Blanco
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Celio D Angelis
- Department of Pharmacology, State University of Campinas, Campinas, SP, Brazil
| | - Alan N Schechter
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Jose E Tanus-Santos
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil.
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104
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Mazidi M, Rezaie P, Kengne AP, Mobarhan MG, Ferns GA. Gut microbiome and metabolic syndrome. Diabetes Metab Syndr 2016; 10:S150-S157. [PMID: 26916014 DOI: 10.1016/j.dsx.2016.01.024] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 01/09/2016] [Indexed: 02/06/2023]
Abstract
The gut microbiome contributes approximately 2kg of the whole body weight, and recent studies suggest that gut microbiota has a profound effect on human metabolism, potentially contributing to several features of the metabolic syndrome. Metabolic syndrome is defined by a clustering of metabolic disorders that include central adiposity with visceral fat accumulation, dyslipidemia, insulin resistance, dysglycemia and non-optimal blood pressure levels. Metabolic syndrome is associated with an increased risk of cardiovascular diseases and type 2 diabetes. It is estimated that around 20-25 percent of the world's adult population has metabolic syndrome. In this manuscript, we have reviewed the existing data linking gut microbiome with metabolic syndrome. Existing evidence from studies both in animals and humans support a link between gut microbiome and various components of metabolic syndrome. Possible pathways include involvement with energy homeostasis and metabolic processes, modulation of inflammatory signaling pathways, interferences with the immune system, and interference with the renin-angiotensin system. Modification of gut microbiota via prebiotics, probiotics or other dietary interventions has provided evidence to support a possible beneficial effect of interventions targeting gut microbiota modulation to treat components or complications of metabolic syndrome.
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Affiliation(s)
- Mohsen Mazidi
- Key State Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Chaoyang, Beijing, China; Institute of Genetics and Developmental Biology, International College, University of Chinese Academy of Science (IC-UCAS), West Beichen Road, Chaoyang, China
| | - Peyman Rezaie
- Biochemistry and Nutrition Research Center, School of Medicine, Mashhad University of Medical Science, Mashhad, Iran
| | - Andre Pascal Kengne
- Non-Communicable Disease Research Unit, South African Medical Research Council and University of Cape Town, Cape Town, South Africa
| | - Majid Ghayour Mobarhan
- Biochemistry and Nutrition Research Center, School of Medicine, Mashhad University of Medical Science, Mashhad, Iran; Cardiovascular Research Center, Mashhad University of Medical Sciences (MUMS), Mashhad, Iran.
| | - Gordon A Ferns
- Brighton & Sussex Medical School, Division of Medical Education, Rm 342, Mayfield House, University of Brighton, BN1 9PH, UK
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105
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Ren X, Ding Y, Lu N. Nitrite attenuated peroxynitrite and hypochlorite generation in activated neutrophils. Eur J Pharmacol 2016; 775:50-6. [DOI: 10.1016/j.ejphar.2016.02.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 02/01/2016] [Accepted: 02/04/2016] [Indexed: 01/15/2023]
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106
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Maruyama D, Hirata N, Tokinaga Y, Kawaguchi R, Yamakage M. Nitrite Reduces Ischemia-Induced Ventricular Arrhythmias by Attenuating Connexin 43 Dephosphorylation in Rats. Anesth Analg 2016; 122:410-7. [DOI: 10.1213/ane.0000000000001063] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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107
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Gee LC, Ahluwalia A. Dietary Nitrate Lowers Blood Pressure: Epidemiological, Pre-clinical Experimental and Clinical Trial Evidence. Curr Hypertens Rep 2016; 18:17. [PMID: 26815004 PMCID: PMC4729801 DOI: 10.1007/s11906-015-0623-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nitric oxide (NO), a potent vasodilator critical in maintaining vascular homeostasis, can reduce blood pressure in vivo. Loss of constitutive NO generation, for example as a result of endothelial dysfunction, occurs in many pathological conditions, including hypertension, and contributes to disease pathology. Attempts to therapeutically deliver NO via organic nitrates (e.g. glyceryl trinitrate, GTN) to reduce blood pressure in hypertensives have been largely unsuccessful. However, in recent years inorganic (or 'dietary') nitrate has been identified as a potential solution for NO delivery through its sequential chemical reduction via the enterosalivary circuit. With dietary nitrate found in abundance in vegetables this review discusses epidemiological, pre-clinical and clinical data supporting the idea that dietary nitrate could represent a cheap and effective dietary intervention capable of reducing blood pressure and thereby improving cardiovascular health.
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Affiliation(s)
- Lorna C Gee
- William Harvey Research Institute, Barts & The London School of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK.
| | - Amrita Ahluwalia
- William Harvey Research Institute, Barts & The London School of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK.
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108
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Woessner M, Smoliga JM, Tarzia B, Stabler T, Van Bruggen M, Allen JD. A stepwise reduction in plasma and salivary nitrite with increasing strengths of mouthwash following a dietary nitrate load. Nitric Oxide 2016; 54:1-7. [PMID: 26778277 DOI: 10.1016/j.niox.2016.01.002] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 01/07/2016] [Accepted: 01/10/2016] [Indexed: 02/07/2023]
Abstract
Nitric Oxide (NO) bioavailability is essential for vascular health. Dietary supplementation with inorganic nitrate, which is abundant in vegetables and roots, has been identified as an effective means of increasing vascular NO bioavailability. Recent studies have shown a reduction in resting blood pressures in both normotensive and hypertensive subjects following ingestion of inorganic nitrate. Oral bacteria play a key role in this process and the use of strong antibacterial mouthwash rinses can disable this mechanism. Hence, mouthwash usage, a $1.4 billion market in the US, may potentially be detrimental to cardiovascular health. The purpose of this study was to examine the effects of different strengths of commercially available mouthwash products on salivary and plasma nitrate and nitrite concentrations following 8.4 mmol inorganic nitrate load (beetroot juice). Specifically, we examined the effects of Listerine antiseptic mouthwash, Cepacol antibacterial mouthwash, and Chlorhexidine mouthwash versus control (water). Twelve apparently healthy normotensive males (36 ± 11 yrs) completed four testing visits in a randomized order, separated by one week. Testing consisted of blood pressure (BP), and saliva and venous blood collection at baseline and each hour for 4 h. Following baseline-testing participants consumed 140 ml of beet juice and then 15 min later gargled with 5 mL of assigned mouthwash. Testing and mouthwash rinse was repeated every hour for 4 h. Linear mixed effects models, followed by pairwise comparisons where appropriate, were used to determine the influence of treatment and time on plasma and saliva nitrate and nitrite, and BP. Plasma and salivary nitrate increased above baseline (time effect) for all conditions (p ≤ 0.01). There were time (p ≤ 0.01), treatment (p ≤ 0.01), and interaction (p ≤ 0.05) effects for plasma and salivary nitrite. There was a treatment effect on systolic BP (p ≤ 0.05). Further examination revealed a differentiation of plasma and salivary nitrite concentration between control/antiseptic and antibacterial/chlorhexidine treatments. When examined in this manner there was a reduction in both SBP (p ≤ 0.01) and mean arterial BP (p ≤ 0.05) from the antibacterial/chlorhexidine treatments. These results suggest a potentially differentiating effect of different commercially available mouthwash solutions on plasma and salivary nitrite concentrations and resting blood pressure responses. This raises potential public health related questions on the appropriate widespread usage of different mouthwash formulations.
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Affiliation(s)
- Mary Woessner
- Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Australia; Duke Molecular Physiology Institute, Duke University, Durham, NC, USA
| | - James M Smoliga
- Institute for Human Health and Sports Science Research, Department of Physical Therapy, High Point University, High Point, NC, USA
| | - Brendan Tarzia
- Duke Molecular Physiology Institute, Duke University, Durham, NC, USA
| | - Thomas Stabler
- Duke Molecular Physiology Institute, Duke University, Durham, NC, USA
| | - Mitch Van Bruggen
- Duke Molecular Physiology Institute, Duke University, Durham, NC, USA
| | - Jason D Allen
- Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Australia; Duke Molecular Physiology Institute, Duke University, Durham, NC, USA.
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109
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Sun Y, Lau CW, Jia Y, Li Y, Wang W, Ran J, Li F, Huang Y, Zhou H, Yang B. Functional inhibition of urea transporter UT-B enhances endothelial-dependent vasodilatation and lowers blood pressure via L-arginine-endothelial nitric oxide synthase-nitric oxide pathway. Sci Rep 2016; 6:18697. [PMID: 26739766 PMCID: PMC4703984 DOI: 10.1038/srep18697] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 11/23/2015] [Indexed: 12/25/2022] Open
Abstract
Mammalian urea transporters (UTs), UT-A and UT-B, are best known for their role in urine concentration. UT-B is especially distributed in multiple extrarenal tissues with abundant expression in vascular endothelium, but little is known about its role in vascular function. The present study investigated the physiological significance of UT-B in regulating vasorelaxations and blood pressure. UT-B deletion in mice or treatment with UT-B inhibitor PU-14 in Wistar-Kyoto rats (WKYs) and spontaneous hypertensive rats (SHRs) reduced blood pressure. Acetylcholine-induced vasorelaxation was significantly augmented in aortas from UT-B null mice. PU-14 concentration-dependently produced endothelium-dependent relaxations in thoracic aortas and mesenteric arteries from both mice and rats and the relaxations were abolished by N(ω)-nitro-L-arginine methyl ester. Both expression and phosphorylation of endothelial nitric oxide synthase (eNOS) were up-regulated and expression of arginase I was down-regulated when UT-B was inhibited both in vivo and in vitro. PU-14 induced endothelium-dependent relaxations to a similar degree in aortas from 12 weeks old SHRs or WKYs. In summary, here we report for the first time that inhibition of UT-B plays an important role in regulating vasorelaxations and blood pressure via up-regulation of L-arginine-eNOS-NO pathway, and it may become another potential therapeutic target for the treatment of hypertension.
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Affiliation(s)
- Yi Sun
- State Key Laboratory of Natural and Biomimetic Drugs, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Chi-Wai Lau
- Institute of Vascular Medicine and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Yingli Jia
- State Key Laboratory of Natural and Biomimetic Drugs, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Yingjie Li
- State Key Laboratory of Natural and Biomimetic Drugs, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Weiling Wang
- State Key Laboratory of Natural and Biomimetic Drugs, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Jianhua Ran
- Department of Anatomy and Neuroscience Center, Chongqing Medical University, Chongqing, China
| | - Fei Li
- State Key Laboratory of Natural and Biomimetic Drugs, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Yu Huang
- Institute of Vascular Medicine and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Hong Zhou
- State Key Laboratory of Natural and Biomimetic Drugs, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Baoxue Yang
- State Key Laboratory of Natural and Biomimetic Drugs, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
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110
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Xanthine Oxidoreductase-Derived Reactive Species: Physiological and Pathological Effects. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:3527579. [PMID: 26823950 PMCID: PMC4707389 DOI: 10.1155/2016/3527579] [Citation(s) in RCA: 159] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 11/01/2015] [Indexed: 12/20/2022]
Abstract
Xanthine oxidoreductase (XOR) is the enzyme that catalyzes the oxidation of hypoxanthine to xanthine and xanthine to uric acid and is widely distributed among species. In addition to this housekeeping function, mammalian XOR is a physiological source of superoxide ion, hydrogen peroxide, and nitric oxide, which can function as second messengers in the activation of various pathways. This review intends to address the physiological and pathological roles of XOR-derived oxidant molecules. The cytocidal action of XOR products has been claimed in relation to tissue damage, in particular damage induced by hypoxia and ischemia. Attempts to exploit this activity to eliminate unwanted cells via the construction of conjugates have also been reported. Moreover, different aspects of XOR activity related to phlogosis, endothelial activation, leukocyte activation, and vascular tone regulation, have been taken into consideration. Finally, the positive and negative outcomes concerning cancer pathology have been analyzed because XOR products may induce mutagenesis, cell proliferation, and tumor progression, but they are also associated with apoptosis and cell differentiation. In conclusion, XOR activity generates free radicals and other oxidant reactive species that may result in either harmful or beneficial outcomes.
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111
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Pinheiro LC, Amaral JH, Ferreira GC, Portella RL, Ceron CS, Montenegro MF, Toledo JC, Tanus-Santos JE. Gastric S-nitrosothiol formation drives the antihypertensive effects of oral sodium nitrite and nitrate in a rat model of renovascular hypertension. Free Radic Biol Med 2015; 87:252-62. [PMID: 26159506 DOI: 10.1016/j.freeradbiomed.2015.06.038] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 06/11/2015] [Accepted: 06/26/2015] [Indexed: 01/01/2023]
Abstract
Many effects of nitrite and nitrate are attributed to increased circulating concentrations of nitrite, ultimately converted into nitric oxide (NO(•)) in the circulation or in tissues by mechanisms associated with nitrite reductase activity. However, nitrite generates NO(•) , nitrous anhydride, and other nitrosating species at low pH, and these reactions promote S-nitrosothiol formation when nitrites are in the stomach. We hypothesized that the antihypertensive effects of orally administered nitrite or nitrate involve the formation of S-nitrosothiols, and that those effects depend on gastric pH. The chronic effects of oral nitrite or nitrate were studied in two-kidney, one-clip (2K1C) hypertensive rats treated with omeprazole (or vehicle). Oral nitrite lowered blood pressure and increased plasma S-nitrosothiol concentrations independently of circulating nitrite levels. Increasing gastric pH with omeprazole did not affect the increases in plasma nitrite and nitrate levels found after treatment with nitrite. However, treatment with omeprazole severely attenuated the increases in plasma S-nitrosothiol concentrations and completely blunted the antihypertensive effects of nitrite. Confirming these findings, very similar results were found with oral nitrate. To further confirm the role of gastric S-nitrosothiol formation, we studied the effects of oral nitrite in hypertensive rats treated with the glutathione synthase inhibitor buthionine sulfoximine (BSO) to induce partial thiol depletion. BSO treatment attenuated the increases in S-nitrosothiol concentrations and antihypertensive effects of oral nitrite. These data show that gastric S-nitrosothiol formation drives the antihypertensive effects of oral nitrite or nitrate and has major implications, particularly to patients taking proton pump inhibitors.
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Affiliation(s)
- Lucas C Pinheiro
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil
| | - Jefferson H Amaral
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil
| | - Graziele C Ferreira
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil
| | - Rafael L Portella
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil
| | - Carla S Ceron
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil
| | - Marcelo F Montenegro
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil
| | - Jose Carlos Toledo
- Department of Chemistry, Faculty of Philosophy and Sciences of Ribeirao Preto, University of Sao Paulo, 14040-901, Ribeirao Preto, SP, Brazil
| | - Jose E Tanus-Santos
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil.
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112
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Gonçalves-Rizzi VH, Nascimento RA, Possomato-Vieira JS, Dias-Junior CA. Sodium Nitrite Prevents both Reductions in Circulating Nitric Oxide and Hypertension in 7-Day Lead-Treated Rats. Basic Clin Pharmacol Toxicol 2015; 118:225-30. [DOI: 10.1111/bcpt.12480] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 08/16/2015] [Indexed: 11/27/2022]
Affiliation(s)
- Victor Hugo Gonçalves-Rizzi
- Department of Pharmacology; Biosciences Institute of Botucatu; Sao Paulo State University - UNESP; Botucatu Sao Paulo Brazil
| | - Regina Aparecida Nascimento
- Department of Pharmacology; Biosciences Institute of Botucatu; Sao Paulo State University - UNESP; Botucatu Sao Paulo Brazil
| | - Jose Sergio Possomato-Vieira
- Department of Pharmacology; Biosciences Institute of Botucatu; Sao Paulo State University - UNESP; Botucatu Sao Paulo Brazil
| | - Carlos A. Dias-Junior
- Department of Pharmacology; Biosciences Institute of Botucatu; Sao Paulo State University - UNESP; Botucatu Sao Paulo Brazil
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113
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Kramkowski K, Leszczynska A, Przyborowski K, Kaminski T, Rykaczewska U, Sitek B, Zakrzewska A, Proniewski B, Smolenski RT, Chabielska E, Buczko W, Chlopicki S. Role of xanthine oxidoreductase in the anti-thrombotic effects of nitrite in ratsin vivo. Platelets 2015; 27:245-53. [DOI: 10.3109/09537104.2015.1083545] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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114
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Rathod KS, Velmurugan S, Ahluwalia A. A 'green' diet-based approach to cardiovascular health? Is inorganic nitrate the answer? Mol Nutr Food Res 2015; 60:185-202. [PMID: 26256112 DOI: 10.1002/mnfr.201500313] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/16/2015] [Accepted: 07/10/2015] [Indexed: 12/22/2022]
Abstract
Ingestion of fruit and vegetables rich in inorganic nitrate (NO(3)(-)) has emerged as an effective method for acutely elevating vascular nitric oxide (NO) levels through formation of an NO(2)(-) intermediate. As such a number of beneficial effects of NO(3)(-) and NO(2)(-) ingestion have been demonstrated including reductions in blood pressure, measures of arterial stiffness and platelet activity. The pathway for NO generation from such dietary interventions involves the activity of facultative oral microflora that facilitate the reduction of inorganic NO(3)(-), ingested in the diet, to inorganic NO(2)(-). This NO(2)(-) then eventually enters the circulation where, through the activity of one or more of a range of distinct NO(2)(-) reductases, it is chemically reduced to NO. This pathway provides an alternative route for in vivo NO generation that could be utilized for therapeutic benefit in those cardiovascular disease states where reduced bioavailable NO is thought to contribute to pathogenesis. Indeed, the cardiovascular benefits of NO(2)(-) and NO(3)(-) are now starting to be translated in patients in several clinical trials. In this review, we discuss recent evidence supporting the potential utility of delivery of NO(3)(-) or NO(2)(-) for the treatment of cardiovascular diseases.
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Affiliation(s)
- Krishnaraj Sinhji Rathod
- William Harvey Research Institute, Barts NIHR Cardiovascular Biomedical Research Unit, Barts & The London Medical School, Queen Mary University of London, Charterhouse Square, London, UK
| | - Shanti Velmurugan
- William Harvey Research Institute, Barts NIHR Cardiovascular Biomedical Research Unit, Barts & The London Medical School, Queen Mary University of London, Charterhouse Square, London, UK
| | - Amrita Ahluwalia
- William Harvey Research Institute, Barts NIHR Cardiovascular Biomedical Research Unit, Barts & The London Medical School, Queen Mary University of London, Charterhouse Square, London, UK
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115
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Ntchapda F, Kakesse M, Fokam MAT, Pancha OM, Abakar D, Dimo T. Evaluation of the diuretic effects of crude stem bark extraction of Zanthoxylum heitzii (Rutaceae) in Wistar rats. JOURNAL OF INTEGRATIVE MEDICINE-JIM 2015; 13:326-35. [DOI: 10.1016/s2095-4964(15)60188-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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116
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McNally B, Griffin JL, Roberts LD. Dietary inorganic nitrate: From villain to hero in metabolic disease? Mol Nutr Food Res 2015; 60:67-78. [PMID: 26227946 PMCID: PMC4863140 DOI: 10.1002/mnfr.201500153] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 07/13/2015] [Accepted: 07/23/2015] [Indexed: 12/22/2022]
Abstract
Historically, inorganic nitrate was believed to be an inert by‐product of nitric oxide (NO) metabolism that was readily excreted by the body. Studies utilising doses of nitrate far in excess of dietary and physiological sources reported potentially toxic and carcinogenic effects of the anion. However, nitrate is a significant component of our diets, with the majority of the anion coming from green leafy vegetables, which have been consistently shown to offer protection against obesity, type 2 diabetes and metabolic diseases. The discovery of a metabolic pathway in mammals, in which nitrate is reduced to NO, via nitrite, has warranted a re‐examination of the physiological role of this small molecule. Obesity, type 2 diabetes and the metabolic syndrome are associated with a decrease in NO bioavailability. Recent research suggests that the nitrate‐nitrite‐NO pathway may be harnessed as a therapeutic to supplement circulating NO concentrations, with both anti‐obesity and anti‐diabetic effects, as well as improving vascular function. In this review, we examine the key studies that have led to the re‐evaluation of the physiological function of inorganic nitrate, from toxic and carcinogenic metabolite, to a potentially important and beneficial agent in the treatment of metabolic disease.
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Affiliation(s)
- Ben McNally
- Elsie Widdowson Laboratory, Medical Research Council - Human Nutrition Research, Cambridge, UK.,Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge, UK
| | - Julian L Griffin
- Elsie Widdowson Laboratory, Medical Research Council - Human Nutrition Research, Cambridge, UK.,Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge, UK
| | - Lee D Roberts
- Elsie Widdowson Laboratory, Medical Research Council - Human Nutrition Research, Cambridge, UK.,Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge, UK
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Ferguson SK, Glean AA, Holdsworth CT, Wright JL, Fees AJ, Colburn TD, Stabler T, Allen JD, Jones AM, Musch TI, Poole DC. Skeletal Muscle Vascular Control During Exercise: Impact of Nitrite Infusion During Nitric Oxide Synthase Inhibition in Healthy Rats. J Cardiovasc Pharmacol Ther 2015; 21:201-8. [PMID: 26272082 DOI: 10.1177/1074248415599061] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 06/17/2015] [Indexed: 12/26/2022]
Abstract
The nitric oxide synthase (NOS)-independent pathway of nitric oxide (NO) production in which nitrite (NO2 (-)) is reduced to NO may have therapeutic applications for those with cardiovascular diseases in which the NOS pathway is downregulated. We tested the hypothesis that NO2 (-) infusion would reduce mean arterial pressure (MAP) and increase skeletal muscle blood flow (BF) and vascular conductance (VC) during exercise in the face of NOS blockade via L-NAME. Following infusion of L-NAME (10 mg kg(-1), L-NAME), male Sprague-Dawley rats (3-6 months, n = 8) exercised without N(G)-nitro-L arginine methyl ester (L-NAME) and after infusion of sodium NO2 (-) (7 mg kg(-1); L-NAME + NO2 (-)). MAP and hindlimb skeletal muscle BF (radiolabeled microsphere infusions) were measured during submaximal treadmill running (20 m min(-1), 5% grade). Across group comparisons were made with a published control data set (n = 11). Relative to L-NAME, NO2 (-) infusion significantly reduced MAP (P < 0.03). The lower MAP in L-NAME+NO2 (-) was not different from healthy control animals (control: 137 ± 3 L-NAME: 157 ± 7, L-NAME + NO2 (-): 136 ± 5 mm Hg). Also, NO2 (-) infusion significantly increased VC when compared to L-NAME (P < 0.03), ultimately negating any significant differences from control animals (control: 0.78 ± 0.05, L-NAME: 0.57 ± 0.03, L-NAME + NO2 (-); 0.69 ± 0.04 mL min(-1) 100 g(-1) mm Hg(-1)) with no apparent fiber-type preferential effect. Overall, hindlimb BF was decreased significantly by L-NAME; however, in L-NAME + NO2 (-), BF improved to a level not significantly different from healthy controls (control: 108 ± 8, L-NAME: 88 ± 3, L-NAME + NO2 (-): 94 ± 6 mL min(-1) 100 g(-1), P = 0.38 L-NAME vs L-NAME + NO2 (-)). Individuals with diseases that impair NOS activity, and thus vascular function, may benefit from a NO2 (-)-based therapy in which NO bioavailability is elevated in an NOS-independent manner.
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Affiliation(s)
- Scott K Ferguson
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA
| | - Angela A Glean
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Clark T Holdsworth
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA
| | - Jennifer L Wright
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA
| | - Alex J Fees
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA
| | - Trenton D Colburn
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Thomas Stabler
- Institute of Sport Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
| | - Jason D Allen
- Institute of Sport Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
| | - Andrew M Jones
- Sport and Health Sciences, University of Exeter, St Luke's Campus, Exeter, United Kingdom
| | - Timothy I Musch
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | - David C Poole
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA Department of Kinesiology, Kansas State University, Manhattan, KS, USA
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118
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Lundberg JO, Gladwin MT, Weitzberg E. Strategies to increase nitric oxide signalling in cardiovascular disease. Nat Rev Drug Discov 2015; 14:623-41. [PMID: 26265312 DOI: 10.1038/nrd4623] [Citation(s) in RCA: 362] [Impact Index Per Article: 40.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nitric oxide (NO) is a key signalling molecule in the cardiovascular, immune and central nervous systems, and crucial steps in the regulation of NO bioavailability in health and disease are well characterized. Although early approaches to therapeutically modulate NO bioavailability failed in clinical trials, an enhanced understanding of fundamental subcellular signalling has enabled a range of novel therapeutic approaches to be identified. These include the identification of: new pathways for enhancing NO synthase activity; ways to amplify the nitrate-nitrite-NO pathway; novel classes of NO-donating drugs; drugs that limit NO metabolism through effects on reactive oxygen species; and ways to modulate downstream phosphodiesterases and soluble guanylyl cyclases. In this Review, we discuss these latest developments, with a focus on cardiovascular disease.
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Affiliation(s)
- Jon O Lundberg
- Department of Physiology and Pharmacology, Karolinska Institute, SE-171 77 Stockholm, Sweden
| | - Mark T Gladwin
- Vascular Medicine Institute, Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pennsylvania 15213, USA
| | - Eddie Weitzberg
- Department of Physiology and Pharmacology, Karolinska Institute, SE-171 77 Stockholm, Sweden
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119
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Bondonno CP, Liu AH, Croft KD, Ward NC, Shinde S, Moodley Y, Lundberg JO, Puddey IB, Woodman RJ, Hodgson JM. Absence of an effect of high nitrate intake from beetroot juice on blood pressure in treated hypertensive individuals: a randomized controlled trial. Am J Clin Nutr 2015; 102:368-75. [PMID: 26135348 DOI: 10.3945/ajcn.114.101188] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 05/22/2015] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Dietary nitrate, which is in green leafy vegetables and beetroot, decreases blood pressure through the enterosalivary nitrate-nitrite-nitric oxide pathway in healthy individuals. Whether similar effects would occur in individuals with treated hypertension and, therefore, at increased risk of cardiovascular disease is unclear. OBJECTIVE We assessed whether increased dietary nitrate intake by using beetroot juice for 1 wk lowers blood pressure in treated hypertensive men and women. DESIGN Participants (n = 27) were recruited to a randomized, placebo-controlled, double-blind crossover trial. The effect of 1-wk intake of nitrate-rich beetroot juice was compared with 1-wk intake of nitrate-depleted beetroot juice (placebo). The primary outcome was blood pressure assessed by measuring home blood pressure during the intervention and 24-h ambulatory blood pressure on day 7 of the intervention. Other outcomes included nitrate metabolism assessed by measuring nitrate and nitrite in plasma, saliva, and urine. RESULTS Relative to the placebo, 1-wk intake of nitrate-rich beetroot juice resulted in a 3-fold increase in plasma nitrite and nitrate, a 7-fold increase in salivary nitrite, an 8-fold higher salivary nitrate, and a 4-fold increase in both urinary nitrite and nitrate (P < 0.001). However, no differences in home blood pressure and 24-h ambulatory blood pressure were observed with 1-wk intake of nitrate-rich beetroot juice in comparison with the placebo. CONCLUSION An increase in dietary nitrate intake may not be an effective short-term approach to further lower blood pressure in treated hypertensive subjects.
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Affiliation(s)
- Catherine P Bondonno
- School of Medicine and Pharmacology, University of Western Australia, Perth, Australia;
| | - Alex H Liu
- School of Medicine and Pharmacology, University of Western Australia, Perth, Australia
| | - Kevin D Croft
- School of Medicine and Pharmacology, University of Western Australia, Perth, Australia
| | - Natalie C Ward
- School of Medicine and Pharmacology, University of Western Australia, Perth, Australia
| | - Sujata Shinde
- School of Medicine and Pharmacology, University of Western Australia, Perth, Australia
| | - Yuben Moodley
- School of Medicine and Pharmacology, University of Western Australia, Perth, Australia
| | - Jon O Lundberg
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden; and
| | - Ian B Puddey
- School of Medicine and Pharmacology, University of Western Australia, Perth, Australia
| | - Richard J Woodman
- Research Centers, School of Medicine, Flinders University, Adelaide, Australia
| | - Jonathan M Hodgson
- School of Medicine and Pharmacology, University of Western Australia, Perth, Australia
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120
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Khambata RS, Ghosh SM, Ahluwalia A. "Repurposing" of Xanthine Oxidoreductase as a Nitrite Reductase: A New Paradigm for Therapeutic Targeting in Hypertension. Antioxid Redox Signal 2015; 23:340-53. [PMID: 25714611 DOI: 10.1089/ars.2015.6254] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
SIGNIFICANCE In contrast to nitric oxide (NO), which has well-established, important effects in regulation of cardiovascular homeostasis, its oxidative metabolite nitrite has, until recently, been considered to be of minor functional significance. RECENT ADVANCES However, this view of nitrite has been radically revised over the past 10 years with evidence now supporting a critical role for this anion as a storage form of NO. CRITICAL ISSUES Importantly, while hypoxia and acidosis have been shown to play a pivotal role in the generation of nitrite to NO, a number of mammalian nitrite reductases have been identified that facilitate the reduction of nitrite. Critically, these nitrite reductases have been demonstrated to operate under physiological pH conditions and in normoxia, extending the functional remit of this anion from an ischemic mediator to an important regulator of physiology. One particular nitrite reductase that has been shown to operate under a wide range of environmental conditions is the enzyme xanthine oxidoreductase (XOR). FUTURE DIRECTIONS In this review, we discuss the evidence supporting a role for XOR as a nitrite reductase while focusing particularly on its function in hypertension. In addition, we discuss the potential merit in exploiting this activity of XOR in the therapeutics of hypertension.
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Affiliation(s)
- Rayomand S Khambata
- The William Harvey Research Institute, Barts NIHR Cardiovascular Biomedical Research Unit, Barts & The London Medical School, Queen Mary University of London , London, United Kingdom
| | - Suborno M Ghosh
- The William Harvey Research Institute, Barts NIHR Cardiovascular Biomedical Research Unit, Barts & The London Medical School, Queen Mary University of London , London, United Kingdom
| | - Amrita Ahluwalia
- The William Harvey Research Institute, Barts NIHR Cardiovascular Biomedical Research Unit, Barts & The London Medical School, Queen Mary University of London , London, United Kingdom
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121
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Wang J, Krizowski S, Fischer-Schrader K, Niks D, Tejero J, Sparacino-Watkins C, Wang L, Ragireddy V, Frizzell S, Kelley EE, Zhang Y, Basu P, Hille R, Schwarz G, Gladwin MT. Sulfite Oxidase Catalyzes Single-Electron Transfer at Molybdenum Domain to Reduce Nitrite to Nitric Oxide. Antioxid Redox Signal 2015; 23:283-94. [PMID: 25314640 PMCID: PMC4523048 DOI: 10.1089/ars.2013.5397] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
AIMS Recent studies suggest that the molybdenum enzymes xanthine oxidase, aldehyde oxidase, and mARC exhibit nitrite reductase activity at low oxygen pressures. However, inhibition studies of xanthine oxidase in humans have failed to block nitrite-dependent changes in blood flow, leading to continued exploration for other candidate nitrite reductases. Another physiologically important molybdenum enzyme—sulfite oxidase (SO)—has not been extensively studied. RESULTS Using gas-phase nitric oxide (NO) detection and physiological concentrations of nitrite, SO functions as nitrite reductase in the presence of a one-electron donor, exhibiting redox coupling of substrate oxidation and nitrite reduction to form NO. With sulfite, the physiological substrate, SO only facilitates one turnover of nitrite reduction. Studies with recombinant heme and molybdenum domains of SO indicate that nitrite reduction occurs at the molybdenum center via coupled oxidation of Mo(IV) to Mo(V). Reaction rates of nitrite to NO decreased in the presence of a functional heme domain, mediated by steric and redox effects of this domain. Using knockdown of all molybdopterin enzymes and SO in fibroblasts isolated from patients with genetic deficiencies of molybdenum cofactor and SO, respectively, SO was found to significantly contribute to hypoxic nitrite signaling as demonstrated by activation of the canonical NO-sGC-cGMP pathway. INNOVATION Nitrite binds to and is reduced at the molybdenum site of mammalian SO, which may be allosterically regulated by heme and molybdenum domain interactions, and contributes to the mammalian nitrate-nitrite-NO signaling pathway in human fibroblasts. CONCLUSION SO is a putative mammalian nitrite reductase, catalyzing nitrite reduction at the Mo(IV) center.
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Affiliation(s)
- Jun Wang
- 1 Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh , Pittsburgh, Pennsylvania.,2 Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Sabina Krizowski
- 3 Department of Biochemistry, Center for Molecular Medicine, Institute of Biochemistry, Cologne University , Cologne, Germany
| | - Katrin Fischer-Schrader
- 3 Department of Biochemistry, Center for Molecular Medicine, Institute of Biochemistry, Cologne University , Cologne, Germany
| | - Dimitri Niks
- 4 Department of Biochemistry, University of California at Riverside , Riverside, California
| | - Jesús Tejero
- 1 Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh , Pittsburgh, Pennsylvania.,2 Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Courtney Sparacino-Watkins
- 1 Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh , Pittsburgh, Pennsylvania.,2 Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Ling Wang
- 1 Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh , Pittsburgh, Pennsylvania.,2 Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Venkata Ragireddy
- 1 Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh , Pittsburgh, Pennsylvania.,2 Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Sheila Frizzell
- 1 Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh , Pittsburgh, Pennsylvania.,2 Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Eric E Kelley
- 1 Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh , Pittsburgh, Pennsylvania.,5 Department of Anesthesiology, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Yingze Zhang
- 2 Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Partha Basu
- 6 Department of Chemistry and Biochemistry, Duquesne University , Pittsburgh, Pennsylvania
| | - Russ Hille
- 4 Department of Biochemistry, University of California at Riverside , Riverside, California
| | - Guenter Schwarz
- 3 Department of Biochemistry, Center for Molecular Medicine, Institute of Biochemistry, Cologne University , Cologne, Germany
| | - Mark T Gladwin
- 1 Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh , Pittsburgh, Pennsylvania.,2 Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania
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Consistent antioxidant and antihypertensive effects of oral sodium nitrite in DOCA-salt hypertension. Redox Biol 2015; 5:340-346. [PMID: 26119848 PMCID: PMC4491646 DOI: 10.1016/j.redox.2015.06.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 06/15/2015] [Accepted: 06/17/2015] [Indexed: 02/01/2023] Open
Abstract
Hypertension is a common disease that includes oxidative stress as a major feature, and oxidative stress impairs physiological nitric oxide (NO) activity promoting cardiovascular pathophysiological mechanisms. While inorganic nitrite and nitrate are now recognized as relevant sources of NO after their bioactivation by enzymatic and non-enzymatic pathways, thus lowering blood pressure, mounting evidence suggests that sodium nitrite also exerts antioxidant effects. Here we show for the first time that sodium nitrite exerts consistent systemic and vascular antioxidant and antihypertensive effects in the deoxycorticosterone-salt (DOCA-salt) hypertension model. This is particularly important because increased oxidative stress plays a major role in the DOCA-salt hypertension model, which is less dependent on activation of the renin-angiotensin system than other hypertension models. Indeed, antihypertensive effects of oral nitrite were associated with increased plasma nitrite and nitrate concentrations, and completely blunted hypertension-induced increases in plasma 8-isoprostane and lipid peroxide levels, in vascular reactive oxygen species, in vascular NADPH oxidase activity, and in vascular xanthine oxidoreductase activity. Together, these findings provide evidence that the oral administration of sodium nitrite consistently decreases the blood pressure in association with major antioxidant effects in experimental hypertension. Nitrite is known to recycle back to NO under specific conditions. Antihypertensive effects have been shown for sodium nitrite in some animal models. The DOCA-salt hypertension model includes oxidative stress as a major pathogenetic mechanism. This study shows antihypertensive effects of nitrite in the DOCA-salt hypertension model. Reduction in arterial blood pressure was associated with important antioxidant effects of sodium nitrite.
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Abstract
PURPOSE OF REVIEW Oxygen (O2) delivery, the maintenance of which is fundamental to supporting those with critical illness, is a function of blood O2 content and flow. Here, we review red blood cell (RBC) physiology relevant to disordered O2 delivery in the critically ill. RECENT FINDINGS Flow (rather than content) is the focus of O2 delivery regulation. O2 content is relatively fixed, whereas flow fluctuates by several orders of magnitude. Thus, blood flow volume and distribution vary to maintain coupling between O2 delivery and demand. The trapping, processing and delivery of nitric oxide (NO) by RBCs has emerged as a conserved mechanism through which regional blood flow is linked to biochemical cues of perfusion sufficiency. We will review conventional RBC physiology that influences O2 delivery (O2 affinity & rheology) and introduce a new paradigm for O2 delivery homeostasis based on coordinated gas transport and vascular signaling by RBCs. SUMMARY By coordinating vascular signaling in a fashion that links O2 and NO flux, RBCs couple vessel caliber (and thus blood flow) to O2 need in tissue. Malfunction of this signaling system is implicated in a wide array of pathophysiologies and may be explanatory for the dysoxia frequently encountered in the critical care setting.
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124
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Yang T, Peleli M, Zollbrecht C, Giulietti A, Terrando N, Lundberg JO, Weitzberg E, Carlström M. Inorganic nitrite attenuates NADPH oxidase-derived superoxide generation in activated macrophages via a nitric oxide-dependent mechanism. Free Radic Biol Med 2015; 83:159-66. [PMID: 25724690 DOI: 10.1016/j.freeradbiomed.2015.02.016] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 02/10/2015] [Accepted: 02/12/2015] [Indexed: 12/16/2022]
Abstract
Oxidative stress contributes to the pathogenesis of many disorders, including diabetes and cardiovascular disease. Immune cells are major sources of superoxide (O2(∙-)) as part of the innate host defense system, but exaggerated and sustained O2(∙-) generation may lead to progressive inflammation and organ injuries. Previous studies have proven organ-protective effects of inorganic nitrite, a precursor of nitric oxide (NO), in conditions manifested by oxidative stress and inflammation. However, the mechanisms are still not clear. This study aimed at investigating the potential role of nitrite in modulating NADPH oxidase (NOX) activity in immune cells. Mice peritoneal macrophages or human monocytes were activated by lipopolysaccharide (LPS), with or without coincubation with nitrite. O2(∙-) and peroxynitrite (ONOO(-)) formation were detected by lucigenin-based chemiluminescence and fluorescence techniques, respectively. The intracellular NO production was measured by DAF-FM DA fluorescence. NOX isoforms and inducible NO synthase (iNOS) expression were detected by qPCR. LPS increased both O2(∙-) and ONOO(-) production in macrophages, which was significantly reduced by nitrite (10µmol/L). Mechanistically, the effects of nitrite are (1) linked to increased NO generation, (2) similar to that observed with the NO donor DETA-NONOate, and (3) can be abolished by the NO scavenger carboxy-PTIO or by the xanthine oxidase (XO) inhibitor febuxostat. Nox2 expression was increased in activated macrophages, but was not influenced by nitrite. However, nitrite attenuated LPS-induced upregulation of iNOS expression. Similar to that observed in mice macrophages, nitrite also reduced O2(∙-) generation in LPS-activated human monocytes. In conclusion, XO-mediated reduction of nitrite attenuates NOX activity in activated macrophages, which may modulate the inflammatory response.
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Affiliation(s)
- Ting Yang
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Maria Peleli
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Christa Zollbrecht
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Alessia Giulietti
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; Department of Clinical Science, Faculty of Medicine, Marche Polytechnic University, Ancona, Italy
| | - Niccolo Terrando
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Jon O Lundberg
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Eddie Weitzberg
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Mattias Carlström
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
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125
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Arif S, Borgognone A, Lin ELS, O'Sullivan AG, Sharma V, Drury NE, Menon A, Nightingale P, Mascaro J, Bonser RS, Horowitz JD, Feelisch M, Frenneaux MP, Madhani M. Role of aldehyde dehydrogenase in hypoxic vasodilator effects of nitrite in rats and humans. Br J Pharmacol 2015; 172:3341-52. [PMID: 25754766 PMCID: PMC4500370 DOI: 10.1111/bph.13122] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 02/09/2015] [Accepted: 02/27/2015] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND AND PURPOSE Hypoxic conditions favour the reduction of nitrite to nitric oxide (NO) to elicit vasodilatation, but the mechanism(s) responsible for bioconversion remains ill defined. In the present study, we assess the role of aldehyde dehydrogenase 2 (ALDH2) in nitrite bioactivation under normoxia and hypoxia in the rat and human vasculature. EXPERIMENTAL APPROACH The role of ALDH2 in vascular responses to nitrite was studied using rat thoracic aorta and gluteal subcutaneous fat resistance vessels from patients with heart failure (HF; 16 patients) in vitro and by measurement of changes in forearm blood flow (FBF) during intra-arterial nitrite infusion (21 patients) in vivo. Specifically, we investigated the effects of (i) ALDH2 inhibition by cyanamide or propionaldehyde and the (ii) tolerance-independent inactivation of ALDH2 by glyceryl trinitrate (GTN) on the vasodilator activity of nitrite. In each setting, nitrite effects were measured via evaluation of the concentration-response relationship under normoxic and hypoxic conditions in the absence or presence of ALDH2 inhibitors. KEY RESULTS Both in rat aorta and human resistance vessels, dilatation to nitrite was diminished following ALDH2 inhibition, in particular under hypoxia. In humans there was a non-significant trend towards attenuation of nitrite-mediated increases in FBF. CONCLUSIONS AND IMPLICATIONS In human and rat vascular tissue in vitro, hypoxic nitrite-mediated vasodilatation involves ALDH2. In patients with HF in vivo, the role of this enzyme in nitrite bioactivation is at the most, modest, suggesting the involvement of other more important mechanisms.
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Affiliation(s)
- Sayqa Arif
- Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Alessandra Borgognone
- Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Erica Lai-Sze Lin
- Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Aine G O'Sullivan
- Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Vishal Sharma
- Department of Cardiology, Royal Liverpool University Hospital, Liverpool, UK
| | - Nigel E Drury
- Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Ashvini Menon
- Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Peter Nightingale
- Wellcome Trust Clinical Research Facility, Queen Elizabeth Hospital, Edgbaston, Birmingham, UK
| | - Jorge Mascaro
- Department of Cardiothoracic Surgery, Queen Elizabeth Hospital, University Hospitals Birmingham, Edgbaston, Birmingham, UK
| | - Robert S Bonser
- Department of Cardiothoracic Surgery, Queen Elizabeth Hospital, University Hospitals Birmingham, Edgbaston, Birmingham, UK
| | - John D Horowitz
- Basil Hetzel Institute, Queen Elizabeth Hospital, University of Adelaide, Adelaide, Australia
| | - Martin Feelisch
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | | | - Melanie Madhani
- Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
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126
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Seals DR, Kaplon RE, Gioscia-Ryan RA, LaRocca TJ. You're only as old as your arteries: translational strategies for preserving vascular endothelial function with aging. Physiology (Bethesda) 2015; 29:250-64. [PMID: 24985329 DOI: 10.1152/physiol.00059.2013] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Endothelial dysfunction develops with age and increases the risk of age-associated vascular disorders. Nitric oxide insufficiency, oxidative stress, and chronic low-grade inflammation, induced by upregulation of adverse cellular signaling processes and imbalances in stress resistance pathways, mediate endothelial dysfunction with aging. Healthy lifestyle behaviors preserve endothelial function with aging by inhibiting these mechanisms, and novel nutraceutical compounds that favorably modulate these pathways hold promise as a complementary approach for preserving endothelial health.
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Affiliation(s)
- Douglas R Seals
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado
| | - Rachelle E Kaplon
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado
| | - Rachel A Gioscia-Ryan
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado
| | - Thomas J LaRocca
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado
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127
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Lara J, Ashor AW, Oggioni C, Ahluwalia A, Mathers JC, Siervo M. Effects of inorganic nitrate and beetroot supplementation on endothelial function: a systematic review and meta-analysis. Eur J Nutr 2015; 55:451-459. [DOI: 10.1007/s00394-015-0872-7] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 03/02/2015] [Indexed: 01/19/2023]
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128
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Omar SA, Fok H, Tilgner KD, Nair A, Hunt J, Jiang B, Taylor P, Chowienczyk P, Webb AJ. Paradoxical normoxia-dependent selective actions of inorganic nitrite in human muscular conduit arteries and related selective actions on central blood pressures. Circulation 2015; 131:381-9; discussion 389. [PMID: 25533964 DOI: 10.1161/circulationaha.114.009554] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Inorganic nitrite dilates small resistance arterioles via hypoxia-facilitated reduction to vasodilating nitric oxide. The effects of nitrite in human conduit arteries have not been investigated. In contrast to nitrite, organic nitrates are established selective dilators of conduit arteries. METHODS AND RESULTS We examined the effects of local and systemic administration of sodium nitrite on the radial artery (a muscular conduit artery), forearm resistance vessels (forearm blood flow), and systemic hemodynamics in healthy male volunteers (n=43). Intrabrachial sodium nitrite (8.7 μmol/min) increased radial artery diameter by a median of 28.0% (25th and 75th percentiles, 25.7% and 40.1%; P<0.001). Nitrite (0.087-87 μmol/min) displayed conduit artery selectivity similar to that of glyceryl trinitrate (0.013-4.4 nmol/min) over resistance arterioles. Nitrite dose-dependently increased local cGMP production at the dose of 2.6 μmol/min by 1.1 pmol·min(-1)·100 mL(-1) tissue (95% confidence interval, 0.5-1.8). Nitrite-induced radial artery dilation was enhanced by administration of acetazolamide (oral or intra-arterial) and oral raloxifene (P=0.0248, P<0.0001, and P=0.0006, respectively) but was inhibited under hypoxia (P<0.0001) and hyperoxia (P=0.0006) compared with normoxia. Systemic intravenous administration of sodium nitrite (8.7 μmol/min) dilated the radial artery by 10.7% (95% confidence interval, 6.8-14.7) and reduced central systolic blood pressure by 11.6 mm Hg (95% confidence interval, 2.4-20.7), augmentation index, and pulse wave velocity without changing peripheral blood pressure. CONCLUSIONS Nitrite selectively dilates conduit arteries at supraphysiological and near-physiological concentrations via a normoxia-dependent mechanism that is associated with cGMP production and is enhanced by acetazolamide and raloxifene. The selective central blood pressure-lowering effects of nitrite have therapeutic potential to reduce cardiovascular events.
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Affiliation(s)
- Sami A Omar
- From the King's College London British Heart Foundation Centre, Cardiovascular Division, Department of Clinical Pharmacology, London, UK (S.A.O., H.F., A.N., J.H., B.J., P.C., A.J.W.); Division of Women's Health, Women's Health Academic Centre, King's College London and King's Health Partners, London, UK (K.D.T., P.T.); Department of Anaesthetics (A.N.), and Biomedical Research Centre (S.A.O., H.F., A.N., J.H., B.J., P.C., A.W.), Guy's & St. Thomas' NHS Foundation Trust, London, UK
| | - Henry Fok
- From the King's College London British Heart Foundation Centre, Cardiovascular Division, Department of Clinical Pharmacology, London, UK (S.A.O., H.F., A.N., J.H., B.J., P.C., A.J.W.); Division of Women's Health, Women's Health Academic Centre, King's College London and King's Health Partners, London, UK (K.D.T., P.T.); Department of Anaesthetics (A.N.), and Biomedical Research Centre (S.A.O., H.F., A.N., J.H., B.J., P.C., A.W.), Guy's & St. Thomas' NHS Foundation Trust, London, UK
| | - Katharina D Tilgner
- From the King's College London British Heart Foundation Centre, Cardiovascular Division, Department of Clinical Pharmacology, London, UK (S.A.O., H.F., A.N., J.H., B.J., P.C., A.J.W.); Division of Women's Health, Women's Health Academic Centre, King's College London and King's Health Partners, London, UK (K.D.T., P.T.); Department of Anaesthetics (A.N.), and Biomedical Research Centre (S.A.O., H.F., A.N., J.H., B.J., P.C., A.W.), Guy's & St. Thomas' NHS Foundation Trust, London, UK
| | - Ashok Nair
- From the King's College London British Heart Foundation Centre, Cardiovascular Division, Department of Clinical Pharmacology, London, UK (S.A.O., H.F., A.N., J.H., B.J., P.C., A.J.W.); Division of Women's Health, Women's Health Academic Centre, King's College London and King's Health Partners, London, UK (K.D.T., P.T.); Department of Anaesthetics (A.N.), and Biomedical Research Centre (S.A.O., H.F., A.N., J.H., B.J., P.C., A.W.), Guy's & St. Thomas' NHS Foundation Trust, London, UK
| | - Joanne Hunt
- From the King's College London British Heart Foundation Centre, Cardiovascular Division, Department of Clinical Pharmacology, London, UK (S.A.O., H.F., A.N., J.H., B.J., P.C., A.J.W.); Division of Women's Health, Women's Health Academic Centre, King's College London and King's Health Partners, London, UK (K.D.T., P.T.); Department of Anaesthetics (A.N.), and Biomedical Research Centre (S.A.O., H.F., A.N., J.H., B.J., P.C., A.W.), Guy's & St. Thomas' NHS Foundation Trust, London, UK
| | - Benyu Jiang
- From the King's College London British Heart Foundation Centre, Cardiovascular Division, Department of Clinical Pharmacology, London, UK (S.A.O., H.F., A.N., J.H., B.J., P.C., A.J.W.); Division of Women's Health, Women's Health Academic Centre, King's College London and King's Health Partners, London, UK (K.D.T., P.T.); Department of Anaesthetics (A.N.), and Biomedical Research Centre (S.A.O., H.F., A.N., J.H., B.J., P.C., A.W.), Guy's & St. Thomas' NHS Foundation Trust, London, UK
| | - Paul Taylor
- From the King's College London British Heart Foundation Centre, Cardiovascular Division, Department of Clinical Pharmacology, London, UK (S.A.O., H.F., A.N., J.H., B.J., P.C., A.J.W.); Division of Women's Health, Women's Health Academic Centre, King's College London and King's Health Partners, London, UK (K.D.T., P.T.); Department of Anaesthetics (A.N.), and Biomedical Research Centre (S.A.O., H.F., A.N., J.H., B.J., P.C., A.W.), Guy's & St. Thomas' NHS Foundation Trust, London, UK
| | - Phil Chowienczyk
- From the King's College London British Heart Foundation Centre, Cardiovascular Division, Department of Clinical Pharmacology, London, UK (S.A.O., H.F., A.N., J.H., B.J., P.C., A.J.W.); Division of Women's Health, Women's Health Academic Centre, King's College London and King's Health Partners, London, UK (K.D.T., P.T.); Department of Anaesthetics (A.N.), and Biomedical Research Centre (S.A.O., H.F., A.N., J.H., B.J., P.C., A.W.), Guy's & St. Thomas' NHS Foundation Trust, London, UK
| | - Andrew J Webb
- From the King's College London British Heart Foundation Centre, Cardiovascular Division, Department of Clinical Pharmacology, London, UK (S.A.O., H.F., A.N., J.H., B.J., P.C., A.J.W.); Division of Women's Health, Women's Health Academic Centre, King's College London and King's Health Partners, London, UK (K.D.T., P.T.); Department of Anaesthetics (A.N.), and Biomedical Research Centre (S.A.O., H.F., A.N., J.H., B.J., P.C., A.W.), Guy's & St. Thomas' NHS Foundation Trust, London, UK.
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129
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Nitrite reduction by molybdoenzymes: a new class of nitric oxide-forming nitrite reductases. J Biol Inorg Chem 2015; 20:403-33. [DOI: 10.1007/s00775-014-1234-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 12/14/2014] [Indexed: 02/07/2023]
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130
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Papapetropoulos A, Hobbs AJ, Topouzis S. Extending the translational potential of targeting NO/cGMP-regulated pathways in the CVS. Br J Pharmacol 2015; 172:1397-414. [PMID: 25302549 DOI: 10.1111/bph.12980] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 09/08/2014] [Accepted: 10/05/2014] [Indexed: 02/06/2023] Open
Abstract
The discovery of NO as both an endogenous signalling molecule and as a mediator of the cardiovascular effects of organic nitrates was acknowledged in 1998 by the Nobel Prize in Physiology/Medicine. The characterization of its downstream signalling, mediated through stimulation of soluble GC (sGC) and cGMP generation, initiated significant translational interest, but until recently this was almost exclusively embodied by the use of PDE5 inhibitors in erectile dysfunction. Since then, research progress in two areas has contributed to an impressive expansion of the therapeutic targeting of the NO-sGC-cGMP axis: first, an increased understanding of the molecular events operating within this complex pathway and second, a better insight into its dys-regulation and uncoupling in human disease. Already-approved PDE5 inhibitors and novel, first-in-class molecules, which up-regulate the activity of sGC independently of NO and/or of the enzyme's haem prosthetic group, are undergoing clinical evaluation to treat pulmonary hypertension and myocardial failure. These molecules, as well as combinations or second-generation compounds, are also being assessed in additional experimental disease models and in patients in a wide spectrum of novel indications, such as endotoxic shock, diabetic cardiomyopathy and Becker's muscular dystrophy. There is well-founded optimism that the modulation of the NO-sGC-cGMP pathway will sustain the development of an increasing number of successful clinical candidates for years to come.
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131
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Maia LB, Pereira V, Mira L, Moura JJG. Nitrite reductase activity of rat and human xanthine oxidase, xanthine dehydrogenase, and aldehyde oxidase: evaluation of their contribution to NO formation in vivo. Biochemistry 2015; 54:685-710. [PMID: 25537183 DOI: 10.1021/bi500987w] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nitrite is presently considered a NO "storage form" that can be made available, through its one-electron reduction, to maintain NO formation under hypoxia/anoxia. The molybdoenzymes xanthine oxidase/dehydrogenase (XO/XD) and aldehyde oxidase (AO) are two of the most promising mammalian nitrite reductases, and in this work, we characterized NO formation by rat and human XO/XD and AO. This is the first characterization of human enzymes, and our results support the employment of rat liver enzymes as suitable models of the human counterparts. A comprehensive kinetic characterization of the effect of pH on XO and AO-catalyzed nitrite reduction showed that the enzyme's specificity constant for nitrite increase 8-fold, while the Km(NO2(-)) decrease 6-fold, when the pH decreases from 7.4 to 6.3. These results demonstrate that the ability of XO/AO to trigger NO formation would be greatly enhanced under the acidic conditions characteristic of ischemia. The dioxygen inhibition was quantified, and the Ki(O2) values found (24.3-48.8 μM) suggest that in vivo NO formation would be fine-tuned by dioxygen availability. The potential in vivo relative physiological relevance of XO/XD/AO-dependent pathways of NO formation was evaluated using HepG2 and HMEC cell lines subjected to hypoxia. NO formation by the cells was found to be pH-, nitrite-, and dioxygen-dependent, and the relative contribution of XO/XD plus AO was found to be as high as 50%. Collectively, our results supported the possibility that XO/XD and AO can contribute to NO generation under hypoxia inside a living human cell. Furthermore, the molecular mechanism of XO/AO-catalyzed nitrite reduction was revised.
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Affiliation(s)
- Luisa B Maia
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa , 2829-516 Caparica, Portugal
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132
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Kennedy CR. Nitrate, Nitrite, and Nitric Oxide Find a Home in the Kidney by Offsetting Angiotensin II–Mediated Hypertension. Hypertension 2015; 65:31-3. [DOI: 10.1161/hypertensionaha.114.04349] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Chris R.J. Kennedy
- From the Kidney Research Centre, Division of Nephrology, Department of Medicine, Ottawa Hospital Research Institute; and Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
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133
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Nitric oxide-dependent vasodilation and Ca2+signalling induced by erythrodiol in rat aorta. ASIAN PACIFIC JOURNAL OF TROPICAL DISEASE 2015. [DOI: 10.1016/s2222-1808(15)60892-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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134
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Gao X, Yang T, Liu M, Peleli M, Zollbrecht C, Weitzberg E, Lundberg JO, Persson AEG, Carlström M. NADPH Oxidase in the Renal Microvasculature Is a Primary Target for Blood Pressure–Lowering Effects by Inorganic Nitrate and Nitrite. Hypertension 2015; 65:161-70. [DOI: 10.1161/hypertensionaha.114.04222] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Renal oxidative stress and nitric oxide (NO) deficiency are key events in hypertension. Stimulation of a nitrate–nitrite–NO pathway with dietary nitrate reduces blood pressure, but the mechanisms or target organ are not clear. We investigated the hypothesis that inorganic nitrate and nitrite attenuate reactivity of renal microcirculation and blood pressure responses to angiotensin II (ANG II) by modulating nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and NO bioavailability. Nitrite in the physiological range (10
−7
–10
−5
mol/L) dilated isolated perfused renal afferent arterioles, which were associated with increased NO. Contractions to ANG II (34%) and simultaneous NO synthase inhibition (56%) were attenuated by nitrite (18% and 26%). In a model of oxidative stress (superoxide dismutase-1 knockouts), abnormal ANG II–mediated arteriolar contractions (90%) were normalized by nitrite (44%). Mechanistically, effects of nitrite were abolished by NO scavenger and xanthine oxidase inhibitor, but only partially attenuated by inhibiting soluble guanylyl cyclase. Inhibition of NADPH oxidase with apocynin attenuated ANG II–induced contractility (35%) similar to that of nitrite. In the presence of nitrite, no further effect of apocynin was observed, suggesting NADPH oxidase as a possible target. In preglomerular vascular smooth muscle cells and kidney cortex, nitrite reduced both basal and ANG II–induced NADPH oxidase activity. These effects of nitrite were also abolished by xanthine oxidase inhibition. Moreover, supplementation with dietary nitrate (10
−2
mol/L) reduced renal NADPH oxidase activity and attenuated ANG II–mediated arteriolar contractions and hypertension (99±2–146±2 mm Hg) compared with placebo (100±3–168±3 mm Hg). In conclusion, these novel findings position NADPH oxidase in the renal microvasculature as a prime target for blood pressure–lowering effects of inorganic nitrate and nitrite.
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Affiliation(s)
- Xiang Gao
- From the Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden (X.G., A.E.G.P.); and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden (T.Y., M.L., M.P., C.Z., E.W., J.O.L., M.C.)
| | - Ting Yang
- From the Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden (X.G., A.E.G.P.); and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden (T.Y., M.L., M.P., C.Z., E.W., J.O.L., M.C.)
| | - Ming Liu
- From the Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden (X.G., A.E.G.P.); and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden (T.Y., M.L., M.P., C.Z., E.W., J.O.L., M.C.)
| | - Maria Peleli
- From the Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden (X.G., A.E.G.P.); and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden (T.Y., M.L., M.P., C.Z., E.W., J.O.L., M.C.)
| | - Christa Zollbrecht
- From the Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden (X.G., A.E.G.P.); and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden (T.Y., M.L., M.P., C.Z., E.W., J.O.L., M.C.)
| | - Eddie Weitzberg
- From the Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden (X.G., A.E.G.P.); and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden (T.Y., M.L., M.P., C.Z., E.W., J.O.L., M.C.)
| | - Jon O. Lundberg
- From the Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden (X.G., A.E.G.P.); and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden (T.Y., M.L., M.P., C.Z., E.W., J.O.L., M.C.)
| | - A. Erik G. Persson
- From the Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden (X.G., A.E.G.P.); and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden (T.Y., M.L., M.P., C.Z., E.W., J.O.L., M.C.)
| | - Mattias Carlström
- From the Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden (X.G., A.E.G.P.); and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden (T.Y., M.L., M.P., C.Z., E.W., J.O.L., M.C.)
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135
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Abstract
Significant effects on blood pressure (BP) have been reported from large nutritional interventions, particularly the Dietary Approaches to Stop Hypertension (DASH) and the Mediterranean diet. In more recent years, numerous studies have investigated the possible BP-lowering effect of different nutraceuticals; these range from specific foods to minerals, lipids, whole proteins, peptides, amino acids, probiotics, and vitamins. While a very large body of evidence supports the use of potassium, L-arginine, vitamins C and D, cocoa flavonoids, beetroot juice, some probiotics, coenzyme Q10, controlled-release melatonin, aged garlic extract, and coffee, the use of other nutraceuticals, such as green tea, flaxseed, and resveratrol, has not as yet been supported by adequate evidence. In some cases, e.g. proteins/peptides, the responsible component needs also to be fully uncovered. Finally, while for most of the products only short-term studies are available, with no specific end-points, an ongoing very large prospective study on chocolate flavanols will answer the question whether this may reduce cardiovascular risk. Thus, in addition to data on long-term safety, further clinical research is advisable in order to identify, among active nutraceuticals, those with the best cost-effectiveness and risk-benefit ratio for a wide use in the general population with a raised cardiovascular risk consequent to uncomplicated hypertension.
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Affiliation(s)
- Cesare R Sirtori
- a Department of Pharmacological and Biomolecular Sciences , University of Milan , Milano , Italy
| | - Anna Arnoldi
- b Department of Pharmaceutical Sciences , University of Milan , Milano , Italy
| | - Arrigo F G Cicero
- c Department of Medical and Surgical Sciences , University of Bologna , Bologna , Italy
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136
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Mills CE, Govoni V, Casagrande ML, Faconti L, Webb AJ, Cruickshank JK. Design and progress of a factorial trial testing the effect of spironolactone and inorganic nitrate on arterial function in people at risk of or with type 2 diabetes. Artery Res 2015. [DOI: 10.1016/j.artres.2015.10.194] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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137
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Liu C, Wajih N, Liu X, Basu S, Janes J, Marvel M, Keggi C, Helms CC, Lee AN, Belanger AM, Diz DI, Laurienti PJ, Caudell DL, Wang J, Gladwin MT, Kim-Shapiro DB. Mechanisms of human erythrocytic bioactivation of nitrite. J Biol Chem 2014; 290:1281-94. [PMID: 25471374 DOI: 10.1074/jbc.m114.609222] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nitrite signaling likely occurs through its reduction to nitric oxide (NO). Several reports support a role of erythrocytes and hemoglobin in nitrite reduction, but this remains controversial, and alternative reductive pathways have been proposed. In this work we determined whether the primary human erythrocytic nitrite reductase is hemoglobin as opposed to other erythrocytic proteins that have been suggested to be the major source of nitrite reduction. We employed several different assays to determine NO production from nitrite in erythrocytes including electron paramagnetic resonance detection of nitrosyl hemoglobin, chemiluminescent detection of NO, and inhibition of platelet activation and aggregation. Our studies show that NO is formed by red blood cells and inhibits platelet activation. Nitric oxide formation and signaling can be recapitulated with isolated deoxyhemoglobin. Importantly, there is limited NO production from erythrocytic xanthine oxidoreductase and nitric-oxide synthase. Under certain conditions we find dorzolamide (an inhibitor of carbonic anhydrase) results in diminished nitrite bioactivation, but the role of carbonic anhydrase is abrogated when physiological concentrations of CO2 are present. Importantly, carbon monoxide, which inhibits hemoglobin function as a nitrite reductase, abolishes nitrite bioactivation. Overall our data suggest that deoxyhemoglobin is the primary erythrocytic nitrite reductase operating under physiological conditions and accounts for nitrite-mediated NO signaling in blood.
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Affiliation(s)
- Chen Liu
- From the Department of Physics and
| | | | | | - Swati Basu
- From the Department of Physics and the Translational Science Center Wake Forest University, Winston-Salem, North Carolina 27109, the Departments of Radiology and
| | | | | | | | | | | | | | - Debra I Diz
- the Translational Science Center Wake Forest University, Winston-Salem, North Carolina 27109, Hypertension and Vascular Research Center and
| | - Paul J Laurienti
- the Translational Science Center Wake Forest University, Winston-Salem, North Carolina 27109, the Departments of Radiology and Biomedical Engineering and
| | - David L Caudell
- Pathology-Comparative Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, and
| | - Jun Wang
- Heart, Lung, Blood, and Vascular Medicine Institute and
| | - Mark T Gladwin
- Heart, Lung, Blood, and Vascular Medicine Institute and the Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213
| | - Daniel B Kim-Shapiro
- From the Department of Physics and the Translational Science Center Wake Forest University, Winston-Salem, North Carolina 27109, Hypertension and Vascular Research Center and Biomedical Engineering and
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138
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Battelli MG, Polito L, Bolognesi A. Xanthine oxidoreductase in atherosclerosis pathogenesis: Not only oxidative stress. Atherosclerosis 2014; 237:562-7. [DOI: 10.1016/j.atherosclerosis.2014.10.006] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 10/12/2014] [Indexed: 02/07/2023]
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139
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Kapil V, Khambata RS, Robertson A, Caulfield MJ, Ahluwalia A. Dietary nitrate provides sustained blood pressure lowering in hypertensive patients: a randomized, phase 2, double-blind, placebo-controlled study. Hypertension 2014; 65:320-7. [PMID: 25421976 DOI: 10.1161/hypertensionaha.114.04675] [Citation(s) in RCA: 329] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
UNLABELLED Single dose administration of dietary inorganic nitrate acutely reduces blood pressure (BP) in normotensive healthy volunteers, via bioconversion to the vasodilator nitric oxide. We assessed whether dietary nitrate might provide sustained BP lowering in patients with hypertension. We randomly assigned 68 patients with hypertension in a double-blind, placebo-controlled clinical trial to receive daily dietary supplementation for 4 weeks with either dietary nitrate (250 mL daily, as beetroot juice) or a placebo (250 mL daily, as nitrate-free beetroot juice) after a 2-week run-in period and followed by a 2-week washout. We performed stratified randomization of drug-naive (n=34) and treated (n=34) patients with hypertension aged 18 to 85 years. The primary end point was change in clinic, ambulatory, and home BP compared with placebo. Daily supplementation with dietary nitrate was associated with reduction in BP measured by 3 different methods. Mean (95% confidence interval) reduction in clinic BP was 7.7/2.4 mm Hg (3.6-11.8/0.0-4.9, P<0.001 and P=0.050). Twenty-four-hour ambulatory BP was reduced by 7.7/5.2 mm Hg (4.1-11.2/2.7-7.7, P<0.001 for both). Home BP was reduced by 8.1/3.8 mm Hg (3.8-12.4/0.7-6.9, P<0.001 and P<0.01) with no evidence of tachyphylaxis over the 4-week intervention period. Endothelial function improved by ≈20% (P<0.001), and arterial stiffness was reduced by 0.59 m/s (0.24-0.93; P<0.01) after dietary nitrate consumption with no change after placebo. The intervention was well tolerated. This is the first evidence of durable BP reduction with dietary nitrate supplementation in a relevant patient group. These findings suggest a role for dietary nitrate as an affordable, readily-available, adjunctive treatment in the management of patients with hypertension (funded by The British Heart Foundation). CLINICAL TRIAL REGISTRATION URL http://www.clinicaltrials.gov. Unique identifier: NCT01405898.
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Affiliation(s)
- Vikas Kapil
- From the William Harvey Research Institute, Barts BP Centre of Excellence, NIHR Cardiovascular Biomedical Research Unit at Barts, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Rayomand S Khambata
- From the William Harvey Research Institute, Barts BP Centre of Excellence, NIHR Cardiovascular Biomedical Research Unit at Barts, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Amy Robertson
- From the William Harvey Research Institute, Barts BP Centre of Excellence, NIHR Cardiovascular Biomedical Research Unit at Barts, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Mark J Caulfield
- From the William Harvey Research Institute, Barts BP Centre of Excellence, NIHR Cardiovascular Biomedical Research Unit at Barts, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Amrita Ahluwalia
- From the William Harvey Research Institute, Barts BP Centre of Excellence, NIHR Cardiovascular Biomedical Research Unit at Barts, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom.
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140
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Nitrate ingestion: a review of the health and physical performance effects. Nutrients 2014; 6:5224-64. [PMID: 25412154 PMCID: PMC4245587 DOI: 10.3390/nu6115224] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 10/21/2014] [Accepted: 11/05/2014] [Indexed: 12/30/2022] Open
Abstract
This paper provides an overview of the current literature and scientific evidence surrounding inorganic nitrate (NO3−) supplementation and its potential for improving human health and physical performance. As indicative of the ever-expanding organic and natural food consumer market, athletes and health enthusiasts alike are constantly searching for ingredient-specific “super foods” and dietary supplements capable of eliciting health and performance benefits. Evidence suggests that NO3− is the viable active component within beetroot juice (BRJ) and other vegetables, responsible for health-promoting and ergogenic effects. Indeed, multiple studies support NO3− supplementation as an effective method to improve exercise performance. NO3− supplementation (either as BRJ or sodium nitrate [NaNO3−]) has also demonstrated modest benefits pertaining to cardiovascular health, such as reducing blood pressure (BP), enhancing blood flow, and elevating the driving pressure of O2 in the microcirculation to areas of hypoxia or exercising tissue. These findings are important to cardiovascular medicine/exercise physiology and suggest a possible role for NO3− supplementation: (1) as a low-cost prevention and treatment intervention for patients suffering from blood flow disorders; and (2) an effective, natural ergogenic aid for athletes. Benefits have been noted following a single bolus, as well as daily supplementation of NO3−. While results are promising, additional research is needed to determine the impact of NO3− supplementation on anaerobic exercise performance, to identify principle relationships between isolated nitrate and other ingredients found in nitrate-rich vegetables (e.g., vitamin C, polyphenols, fatty acids, thiocyanate), to explore the specific dose-response relationships needed to elicit health and ergogenic benefits, to prolong the supplementation period beyond a relatively short period (i.e., >15 days), to determine if more robust effects can be observed with longer-term treatment, and to fully examine the safety of chronic NO3− supplementation, as this continues to be a concern of some.
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141
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Kramkowski K, Agnieszka L, Kamil P, Kaminski T, Rykaczewska U, Sitek B, Proniewski B, Chmura-Skirlinska A, Buczko W. Anti-platelet effect of nitrite in vivo dependents on xanthine oxidoreductase (XOR). Nitric Oxide 2014. [DOI: 10.1016/j.niox.2014.09.091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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142
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Pathophysiology of circulating xanthine oxidoreductase: New emerging roles for a multi-tasking enzyme. Biochim Biophys Acta Mol Basis Dis 2014; 1842:1502-17. [DOI: 10.1016/j.bbadis.2014.05.022] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 05/21/2014] [Accepted: 05/22/2014] [Indexed: 02/07/2023]
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143
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Rassaf T, Ferdinandy P, Schulz R. Nitrite in organ protection. Br J Pharmacol 2014; 171:1-11. [PMID: 23826831 DOI: 10.1111/bph.12291] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 06/09/2013] [Accepted: 06/21/2013] [Indexed: 12/15/2022] Open
Abstract
In the last decade, the nitrate-nitrite-nitric oxide pathway has emerged to therapeutical importance. Modulation of endogenous nitrate and nitrite levels with the subsequent S-nitros(yl)ation of the downstream signalling cascade open the way for novel cytoprotective strategies. In the following, we summarize the actual literature and give a short overview on the potential of nitrite in organ protection.
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Affiliation(s)
- Tienush Rassaf
- Department of Medicine, Division of Cardiology, Pulmonary and Vascular Medicine, University Hospital Düsseldorf, Düsseldorf, Germany
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144
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Bailey JC, Feelisch M, Horowitz JD, Frenneaux MP, Madhani M. Pharmacology and therapeutic role of inorganic nitrite and nitrate in vasodilatation. Pharmacol Ther 2014; 144:303-20. [PMID: 24992304 DOI: 10.1016/j.pharmthera.2014.06.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 06/25/2014] [Indexed: 02/07/2023]
Abstract
Nitrite has emerged as an important bioactive molecule that can be biotransformed to nitric oxide (NO) related metabolites in normoxia and reduced to NO under hypoxic and acidic conditions to exert vasodilatory effects and confer a variety of other benefits to the cardiovascular system. Abundant research is currently underway to understand the mechanisms involved and define the role of nitrite in health and disease. In this review we discuss the impact of nitrite and dietary nitrate on vascular function and the potential therapeutic role of nitrite in acute heart failure.
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Affiliation(s)
- J C Bailey
- Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, UK
| | - M Feelisch
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - J D Horowitz
- The Queen Elizabeth Hospital, Adelaide, Australia
| | - M P Frenneaux
- School of Medicine and Dentistry, University of Aberdeen, Aberdeen, UK
| | - M Madhani
- Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, UK.
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145
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The antihypertensive effects of sodium nitrite are not associated with circulating angiotensin converting enzyme inhibition. Nitric Oxide 2014; 40:52-9. [PMID: 24878382 DOI: 10.1016/j.niox.2014.05.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 05/04/2014] [Accepted: 05/20/2014] [Indexed: 01/15/2023]
Abstract
Nitrite-derived nitric oxide (NO) formation exerts antihypertensive effects. Because NO inhibits angiotensin converting enzyme (ACE) activity, we carried a comprehensive series of experiments in rats to test the hypothesis that sodium nitrite exerts antihypertensive effects by inhibiting ACE. We examined whether sodium nitrite (15 mg/kg; or vehicle; by gavage): (I) attenuates the pressor responses to angiotensin I at doses of 0.03, 0.1, 0.3, 1, 3, and 10 μg/kg intravenously; (II) attenuates the acute hypertension induced by L-NAME (100 mg/kg; or vehicle; by gavage); (III) attenuates the chronic hypertension induced by L-NAME (1 g/L in drinking water; or vehicle) administered for 6 weeks; (IV) attenuates the hypertension in the 2 kidney-1 clip (2K1C) chronic hypertension model. Blood samples were collected at the end of each study and plasma angiotensin converting enzyme (ACE) activity was measured with a fluorimetric assay using Hippuryl-His-Leu as substrate. ACE inhibitors were used as positive controls. Plasma nitrite concentrations were measured by ozone-based reductive chemiluminescence. The in vitro effects of sodium nitrite (0, 1, 3, 10, 30, 100 μmol/L) on plasma ACE activity were also determined. We found that sodium nitrite did not affect the pressor responses to angiotensin I. Moreover, while sodium nitrite exerted significant antihypertensive effects in acute and chronic hypertension models, no significant effects on plasma ACE activity were found. In vitro experiments showed no effects of sodium nitrite on plasma ACE activity. This is the first study to demonstrate that the acute and chronic antihypertensive effects of sodium nitrite are not associated with significant inhibition of circulating ACE activity.
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146
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Kim-Shapiro DB, Gladwin MT. Mechanisms of nitrite bioactivation. Nitric Oxide 2014; 38:58-68. [PMID: 24315961 PMCID: PMC3999231 DOI: 10.1016/j.niox.2013.11.002] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 11/19/2013] [Accepted: 11/21/2013] [Indexed: 12/18/2022]
Abstract
It is now accepted that the anion nitrite, once considered an inert oxidation product of nitric oxide (NO), contributes to hypoxic vasodilation, physiological blood pressure control, and redox signaling. As such, its application in therapeutics is being actively tested in pre-clinical models and in human phase I-II clinical trials. Major pathways for nitrite bioactivation involve its reduction to NO by members of the hemoglobin or molybdopterin family of proteins, or catalyzed dysproportionation. These conversions occur preferentially under hypoxic and acidic conditions. A number of enzymatic systems reduce nitrite to NO and their activity and importance are defined by oxygen tension, specific organ system and allosteric and redox effectors. In this work, we review different proposed mechanisms of nitrite bioactivation, focusing on analysis of kinetics and experimental evidence for the relevance of each mechanism under different conditions.
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Affiliation(s)
- Daniel B Kim-Shapiro
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, United States; Translational Science Center, Wake Forest University, Winston-Salem, NC 27109, United States.
| | - Mark T Gladwin
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15213, United States; Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA 15213, United States.
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147
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Vascular xanthine oxidoreductase contributes to the antihypertensive effects of sodium nitrite in l-NAME hypertension. Naunyn Schmiedebergs Arch Pharmacol 2014; 387:591-8. [DOI: 10.1007/s00210-014-0970-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 02/24/2014] [Indexed: 12/17/2022]
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148
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Clinical evidence demonstrating the utility of inorganic nitrate in cardiovascular health. Nitric Oxide 2014; 38:45-57. [PMID: 24650698 DOI: 10.1016/j.niox.2014.03.162] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 03/04/2014] [Accepted: 03/09/2014] [Indexed: 02/03/2023]
Abstract
The discovery of nitric oxide and its role in almost every facet of human biology opened a new avenue for treatment through manipulation of its canonical signaling and by attempts to augment endogenous nitric oxide generation through provision of substrate and co-factors to the endothelial nitric oxide synthase complex. This has been particularly so in the cardiovascular system and it is well recognized that there is reduced bioavailable nitric oxide in patients with both cardiovascular risk factors and manifest vascular disease. However, these attempts have failed to deliver the expected benefits of such an approach. Recently, an alternative pathway for nitric oxide synthesis has been elucidated that can produce authentic nitric oxide from the 1 electron reduction of inorganic nitrite. Furthermore, it has long been known that symbiotic, facultative, oral microflora can facilitate the reduction of inorganic nitrate, that is ingested in the average diet in millimolar amounts, to inorganic nitrite itself. Thus, there exists an alternative reductive pathway from nitrate, via nitrite as an intermediate, to nitric oxide that provides a novel pathway that may be amenable to therapeutic manipulation. As such, various research groups have explored the utility of manipulation of this nitrate-nitrite-nitric oxide pathway in situations in which nitric oxide is known to have a prominent role. Animal and early-phase human studies of both inorganic nitrite and nitrate supplementation have shown beneficial effects in blood pressure control, platelet function, vascular health and exercise capacity. This review considers in detail the pathways of inorganic nitrate bioactivation and the evidence of clinical utility to date on the cardiovascular system.
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149
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Sindler AL, Devan AE, Fleenor BS, Seals DR. Inorganic nitrite supplementation for healthy arterial aging. J Appl Physiol (1985) 2014; 116:463-77. [PMID: 24408999 PMCID: PMC3949212 DOI: 10.1152/japplphysiol.01100.2013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 01/03/2014] [Indexed: 12/12/2022] Open
Abstract
Aging is the major risk factor for cardiovascular diseases (CVD). This is attributable primarily to adverse changes in arteries, notably, increases in large elastic artery stiffness and endothelial dysfunction mediated by inadequate concentrations of the vascular-protective molecule, nitric oxide (NO), and higher levels of oxidative stress and inflammation. Inorganic nitrite is a promising precursor molecule for augmenting circulating and tissue NO bioavailability because it requires only a one-step reduction to NO. Nitrite also acts as an independent signaling molecule, exerting many of the effects previously attributed to NO. Results of recent studies indicate that nitrite may be effective in the treatment of vascular aging. In old mice, short-term oral sodium nitrite supplementation reduces aortic pulse wave velocity, the gold-standard measure of large elastic artery stiffness, and ameliorates endothelial dysfunction, as indicated by normalization of NO-mediated endothelium-dependent dilation. These improvements in age-related vascular dysfunction with nitrite are mediated by reductions in oxidative stress and inflammation, and may be linked to increases in mitochondrial biogenesis and health. Increasing nitrite levels via dietary intake of nitrate appears to have similarly beneficial effects in many of the same physiological and clinical settings. Several clinical trials are being performed to determine the broad therapeutic potential of increasing nitrite bioavailability on human health and disease, including studies related to vascular aging. In summary, inorganic nitrite, as well as dietary nitrate supplementation, represents a promising therapy for treatment of arterial aging and prevention of age-associated CVD in humans.
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Affiliation(s)
- Amy L Sindler
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado
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150
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Omar SA, Webb AJ. Nitrite reduction and cardiovascular protection. J Mol Cell Cardiol 2014; 73:57-69. [PMID: 24486197 DOI: 10.1016/j.yjmcc.2014.01.012] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 01/20/2014] [Accepted: 01/22/2014] [Indexed: 10/25/2022]
Abstract
Inorganic nitrite, a metabolite of endogenously produced nitric oxide (NO) from NO synthases (NOS), provides the largest endocrine source of directly bioavailable NO. The conversion of nitrite to NO occurs mainly through enzymatic reduction, mediated by a range of proteins, including haem-globins, molybdo-flavoproteins, mitochondrial proteins, cytochrome P450 enzymes, and NOS. Such nitrite reduction is particularly favoured under hypoxia, when endogenous formation of NO from NOS is impaired. Under normoxic conditions, the majority of these nitrite reductases also scavenge NO, or diminish its bioavailability via reactive oxygen species (ROS) production, suggesting an intricate balance. Moreover, nitrite, whether produced endogenously, or derived from exogenous nitrite or nitrate administration (including dietary sources via the Nitrate-Nitrite-NO pathway) beneficially modulates many key cardiovascular pathological processes. In this review, we highlight the landmark studies which revealed nitrite's function in biological systems, and inspect its evolving role in cardiovascular protection. Whilst these effects have mainly been ascribed to the activity of one or more nitrite reductases, we also discuss newly-identified mechanisms, including nitrite anhydration, the involvement of s-nitrosothiols, nitro-fatty acids, and direct nitrite normoxic signalling, involving modification of mitochondrial structure and function, and ROS production. This article is part of a Special Issue entitled "Redox Signalling in the Cardiovascular System".
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Affiliation(s)
- Sami A Omar
- King's College London British Heart Foundation Centre, Cardiovascular Division, Department of Clinical Pharmacology, 4th Floor North Wing, St. Thomas' Hospital, London SE1 7EH, UK; Biomedical Research Centre, Guy's & St Thomas' NHS Foundation Trust, London, UK.
| | - Andrew James Webb
- King's College London British Heart Foundation Centre, Cardiovascular Division, Department of Clinical Pharmacology, 4th Floor North Wing, St. Thomas' Hospital, London SE1 7EH, UK; Biomedical Research Centre, Guy's & St Thomas' NHS Foundation Trust, London, UK.
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