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Toprak K, Kaplangöray M, Memioglu T, İnanır M, Biçer A, Demirbağ R, Erdoğdu H. The Relationship Between Nitrate-Induced Headache and -Blood Viscosity: An Observational Prospective Study. J Cardiovasc Pharmacol 2023; 82:162-168. [PMID: 37314267 DOI: 10.1097/fjc.0000000000001443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 05/27/2023] [Indexed: 06/15/2023]
Abstract
ABSTRACT Nitrates are one of the most prescribed medications in the treatment of angina pectoris today. Headache is the most common side effect of nitrates, and there is limited prospective data on the determinants of this effect. Our aim in this study is to open a foresight window for clinicians in clinical practice by explaining the possible relationship between nitrate-induced headache and whole-blood viscosity (WBV). After coronary revascularization treatment, 869 patients with angina who were prescribed nitrate preparations were divided into groups according to the development of headache or not and categorized according to the 4-grade scale level. Those who had no headache during nitrate use were graded as grade 0, those who felt mild headache were grade 1, those who felt moderate headache were grade 2, and those who described severe headache were graded as grade 3. The groups were compared according to WBV values. A total of 869 participants were included in the study. Most patients (82.1%) experienced some level of headache. Headache severity correlated with both WBV at high shear rate (r = 0.657; P < 0.001) and WBV at low shear rate (r = 0.687; P < 0.001). In multivariate analysis, WBV was determined as an independent predictor of headache experience. WBV predicted nitrate-induced headache with 75% sensitivity and 75% specificity at high shear rate and 77% sensitivity and 77% specificity at low shear rate. WBV seems to be one of the major determinants for nitrate-induced headache. WBV may be a guide for initiating alternative antianginal drugs without prescribing nitrates to the patient to increase patient compliance.
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Affiliation(s)
- Kenan Toprak
- Department of Cardiology, Faculty of Medicine, Harran University, Sanliurfa, Turkey
| | - Mustafa Kaplangöray
- Cardiology Department, Faculty of Medicine, Şeyh Edebali University, Bilecik, Turkey
| | - Tolga Memioglu
- Cardiology Department, Medical Faculty, Bolu Abant Izzet Baysal University, Bolu, Turkey; and
| | - Mehmet İnanır
- Cardiology Department, Medical Faculty, Bolu Abant Izzet Baysal University, Bolu, Turkey; and
| | - Asuman Biçer
- Department of Cardiology, Faculty of Medicine, Harran University, Sanliurfa, Turkey
| | - Recep Demirbağ
- Department of Cardiology, Faculty of Medicine, Harran University, Sanliurfa, Turkey
| | - Hamza Erdoğdu
- Department of Biostatistics, Faculty of Medicine, Harran University, Sanliurfa, Turkey
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Bahadoran Z, Jeddi S, Gheibi S, Mirmiran P, Kashfi K, Ghasemi A. Inorganic nitrate, a natural anti-obesity agent: A systematic review and meta-analysis of animal studies. EXCLI JOURNAL 2020; 19:972-983. [PMID: 32788911 PMCID: PMC7415936 DOI: 10.17179/excli2020-2515] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 06/30/2020] [Indexed: 01/14/2023]
Abstract
Evidence for potential effects of inorganic nitrate (NO3) on body weight is limited to inconsistent findings of animal experiments. In this systematic review and meta-analysis, we aimed to quantify the overall effect of inorganic NO3, administered via drinking water, on body weight gain in rats. We searched PubMed, Scopus, and Embase databases, and the reference lists of published papers. Experiments on male rats, reported data on body weight in NO3-treated animals and controls, were included for quality assessment, meta-analyses, subgroup analyses, and meta-regressions. Of 173 initially obtained studies, 11 were eligible to be included in the analyses, which covered the years 2004 to 2019 and included a total of 43 intervention (n=395) and 43 control (n=395) arms. Overall, the final body weights were significantly lower in the NO3-supplemented groups compared to controls (WMD= -16.8 g, 95 % CI= -27.38, -6.24; P=0.002). Doses of NO3 higher than the median (> 72.94 mg L-1 d-1) and longer NO3 exposure (> 8 weeks) resulted in greater mean differences (WMD= -31.92 g, 95 % CI= -52.90, -10.94 and WMD= -23.16 g, 95 % CI= -35.64, -10.68 g). After exclusion of experiments using high doses of NO3 (> 400 mg L-1 d-1), the overall mean differences in body weights between the groups decreased by approximately 37 % but remained statistically significant (WMD= -10.11 g, 95 % CI= -19.04, -1.19, P=0.026). Mean changes in body weight were affected by age, baseline values in body weight, and the duration of the studies. These preliminary experimental findings strongly support the hypothesis that NO3 can be considered as a natural anti-obesity agent.
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Affiliation(s)
- Zahra Bahadoran
- Nutrition and Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sajad Jeddi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sevda Gheibi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Clinical Sciences in Malmö, Unit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
| | - Parvin Mirmiran
- Department of Clinical Nutrition and Human Dietetics, Faculty of Nutrition Sciences and Food Technology, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Khosrow Kashfi
- Department of Molecular, Cellular and Biomedical Sciences, Sophie Davis School of Biomedical Education, City University of New York School of Medicine, New York, NY 10031, USA
| | - Asghar Ghasemi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Bhandari S, Cavalleri GL. Population History and Altitude-Related Adaptation in the Sherpa. Front Physiol 2019; 10:1116. [PMID: 31555147 PMCID: PMC6722185 DOI: 10.3389/fphys.2019.01116] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 08/12/2019] [Indexed: 12/29/2022] Open
Abstract
The first ascent of Mount Everest by Tenzing Norgay and Sir Edmund Hillary in 1953 brought global attention to the Sherpa people and human performance at altitude. The Sherpa inhabit the Khumbu Valley of Nepal, and are descendants of a population that has resided continuously on the Tibetan plateau for the past ∼25,000 to 40,000 years. The long exposure of the Sherpa to an inhospitable environment has driven genetic selection and produced distinct adaptive phenotypes. This review summarizes the population history of the Sherpa and their physiological and genetic adaptation to hypoxia. Genomic studies have identified robust signals of positive selection across EPAS1, EGLN1, and PPARA, that are associated with hemoglobin levels, which likely protect the Sherpa from altitude sickness. However, the biological underpinnings of other adaptive phenotypes such as birth weight and the increased reproductive success of Sherpa women are unknown. Further studies are required to identify additional signatures of selection and refine existing Sherpa-specific adaptive phenotypes to understand how genetic factors have underpinned adaptation in this population. By correlating known and emerging signals of genetic selection with adaptive phenotypes, we can further reveal hypoxia-related biological mechanisms of adaptation. Ultimately this work could provide valuable information regarding treatments of hypoxia-related illnesses including stroke, heart failure, lung disease and cancer.
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Affiliation(s)
- Sushil Bhandari
- Department of Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Gianpiero L Cavalleri
- Department of Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
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Khorasani V, Jeddi S, Yaghmaei P, Tohidi M, Ghasemi A. Effect of long-term sodium nitrate administration on diabetes-induced anemia and glucose homeostasis in obese type 2 diabetic male rats. Nitric Oxide 2019; 86:21-30. [DOI: 10.1016/j.niox.2019.02.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 02/04/2019] [Accepted: 02/13/2019] [Indexed: 01/20/2023]
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Horscroft JA, O'Brien KA, Clark AD, Lindsay RT, Steel AS, Procter NEK, Devaux J, Frenneaux M, Harridge SDR, Murray AJ. Inorganic nitrate, hypoxia, and the regulation of cardiac mitochondrial respiration-probing the role of PPARα. FASEB J 2019; 33:7563-7577. [PMID: 30870003 PMCID: PMC6529343 DOI: 10.1096/fj.201900067r] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Dietary inorganic nitrate prevents aspects of cardiac mitochondrial dysfunction induced by hypoxia, although the mechanism is not completely understood. In both heart and skeletal muscle, nitrate increases fatty acid oxidation capacity, and in the latter case, this involves up-regulation of peroxisome proliferator-activated receptor (PPAR)α expression. Here, we investigated whether dietary nitrate modifies mitochondrial function in the hypoxic heart in a PPARα-dependent manner. Wild-type (WT) mice and mice without PPARα (Ppara−/−) were given water containing 0.7 mM NaCl (control) or 0.7 mM NaNO3 for 35 d. After 7 d, mice were exposed to normoxia or hypoxia (10% O2) for the remainder of the study. Mitochondrial respiratory function and metabolism were assessed in saponin-permeabilized cardiac muscle fibers. Environmental hypoxia suppressed mass-specific mitochondrial respiration and additionally lowered the proportion of respiration supported by fatty acid oxidation by 18% (P < 0.001). This switch away from fatty acid oxidation was reversed by nitrate treatment in hypoxic WT but not Ppara−/− mice, indicating a PPARα-dependent effect. Hypoxia increased hexokinase activity by 33% in all mice, whereas lactate dehydrogenase activity increased by 71% in hypoxic WT but not Ppara−/− mice. Our findings indicate that PPARα plays a key role in mediating cardiac metabolic remodeling in response to both hypoxia and dietary nitrate supplementation.—Horscroft, J. A., O’Brien, K. A., Clark, A. D., Lindsay, R. T., Steel, A. S., Procter, N. E. K., Devaux, J., Frenneaux, M., Harridge, S. D. R., Murray, A. J. Inorganic nitrate, hypoxia, and the regulation of cardiac mitochondrial respiration—probing the role of PPARα.
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Affiliation(s)
- James A Horscroft
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Katie A O'Brien
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,Centre for Human and Applied Physiological Sciences, King's College London, London, United Kingdom; and
| | - Anna D Clark
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Ross T Lindsay
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Alice Strang Steel
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Nathan E K Procter
- Bob Champion Research and Education Building, University of East Anglia, Norwich, United Kingdom
| | - Jules Devaux
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Michael Frenneaux
- Bob Champion Research and Education Building, University of East Anglia, Norwich, United Kingdom
| | - Stephen D R Harridge
- Centre for Human and Applied Physiological Sciences, King's College London, London, United Kingdom; and
| | - Andrew J Murray
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
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Allan PD, Tzeng YC, Gowing EK, Clarkson AN, Fan JL. Dietary nitrate supplementation reduces low frequency blood pressure fluctuations in rats following distal middle cerebral artery occlusion. J Appl Physiol (1985) 2018; 125:862-869. [DOI: 10.1152/japplphysiol.01081.2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
It is known that high blood pressure variability (BPV) in acute ischemic stroke is associated with adverse outcomes, yet there are no therapeutic treatments to reduce BPV. Studies have found increasing nitric oxide (NO) bioavailability improves neurological function following stroke, but whether dietary nitrate supplementation could reduce BPV remains unknown. We investigated the effects of dietary nitrate supplementation on heart rate (HR), blood pressure (BP), and beat-to-beat BPV using wireless telemetry in a rat model of distal middle cerebral artery occlusion. Blood pressure variability was characterized by spectral power analysis in the low frequency (LF; 0.2–0.6 Hz) range prestroke and during the 7 days poststroke in a control group ( n = 8) and a treatment group ( n = 8, 183 mg/l sodium nitrate in drinking water). Dietary nitrate supplementation moderately reduced systolic BPV in the LF range by ~11% compared with the control group ( P = 0.03), while resting BP and HR were not different between the two groups ( P = 0.28 and 0.33, respectively). Despite systolic BPV being reduced with dietary nitrate, we found no difference in infarct volumes between the treatment and the control groups (1.59 vs. 1.62 mm3, P = 0.86). These findings indicate that dietary nitrate supplementation is effective in reducing systolic BPV following stroke without affecting absolute BP. In light of mounting evidence linking increased BPV with poor stroke patient outcome, our data support the role of dietary nitrate as an adjunct treatment following ischemic stroke. NEW & NOTEWORTHY Using a rat model of stroke, we found that dietary nitrate supplementation reduced low frequency blood pressure fluctuations following stroke without affecting absolute blood pressure values. Since blood pressure fluctuations are associated with poor clinical outcome in stroke patients, our findings indicate that dietary nitrate could be an effective strategy for reducing blood pressure fluctuations, which could help reduce stroke severity and improve patient recovery.
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Affiliation(s)
- Philip D. Allan
- Department of Surgery and Anaesthesia, Centre for Translational Physiology, University of Otago, Wellington, New Zealand
- Wellington Medical Technology Group, Department of Surgery & Anaesthesia, University of Otago, Wellington, New Zealand
| | - Yu-Chieh Tzeng
- Department of Surgery and Anaesthesia, Centre for Translational Physiology, University of Otago, Wellington, New Zealand
- Wellington Medical Technology Group, Department of Surgery & Anaesthesia, University of Otago, Wellington, New Zealand
| | - Emma K. Gowing
- Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - Andrew N. Clarkson
- Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
- Faculty of Pharmacy, The University of Sydney, New South Wales, Australia
| | - Jui-Lin Fan
- Department of Surgery and Anaesthesia, Centre for Translational Physiology, University of Otago, Wellington, New Zealand
- Wellington Medical Technology Group, Department of Surgery & Anaesthesia, University of Otago, Wellington, New Zealand
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Metabolic adjustment to high-altitude hypoxia: from genetic signals to physiological implications. Biochem Soc Trans 2018; 46:599-607. [PMID: 29678953 DOI: 10.1042/bst20170502] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 03/24/2018] [Accepted: 03/27/2018] [Indexed: 01/04/2023]
Abstract
Ascent to high altitude is associated with physiological responses that counter the stress of hypobaric hypoxia by increasing oxygen delivery and by altering tissue oxygen utilisation via metabolic modulation. At the cellular level, the transcriptional response to hypoxia is mediated by the hypoxia-inducible factor (HIF) pathway and results in promotion of glycolytic capacity and suppression of oxidative metabolism. In Tibetan highlanders, gene variants encoding components of the HIF pathway have undergone selection and are associated with adaptive phenotypic changes, including suppression of erythropoiesis and increased blood lactate levels. In some highland populations, there has also been a selection of variants in PPARA, encoding peroxisome proliferator-activated receptor alpha (PPARα), a transcriptional regulator of fatty acid metabolism. In one such population, the Sherpas, lower muscle PPARA expression is associated with a decreased capacity for fatty acid oxidation, potentially improving the efficiency of oxygen utilisation. In lowlanders ascending to altitude, a similar suppression of fatty acid oxidation occurs, although the underlying molecular mechanism appears to differ along with the consequences. Unlike lowlanders, Sherpas appear to be protected against oxidative stress and the accumulation of intramuscular lipid intermediates at altitude. Moreover, Sherpas are able to defend muscle ATP and phosphocreatine levels in the face of decreased oxygen delivery, possibly due to suppression of ATP demand pathways. The molecular mechanisms allowing Sherpas to successfully live, work and reproduce at altitude may hold the key to novel therapeutic strategies for the treatment of diseases to which hypoxia is a fundamental contributor.
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Bullock T, Bruce LJ, Ridgwell K. Current topics in red cell biology: report on the Red Cell Special Interest Group meeting held at NHS Blood and Transplant Bristol on 30 October 2015. Transfus Med 2016; 26:241-5. [PMID: 27221954 DOI: 10.1111/tme.12316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 05/01/2016] [Indexed: 11/29/2022]
Abstract
The Red Cell Special Interest Group (SIG) meeting, hosted by the British Blood Transfusion Society, provides an annual forum for the presentation of UK- and European-based red cell research. The 2015 meeting was held on Friday 30 October at the National Health Service Blood & Transplant (NHSBT) facility in Filton, Bristol and provided an exciting and varied programme on the themes of erythropoiesis, malaria biology and pathophysiology and red cells properties in stress and disease. Ten speakers presented on these topics over the course of one day. The meeting was well attended by over 90 delegates. Posters were presented during the lunch break, and abstracts from the posters are published at the end of this issue.
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Affiliation(s)
- T Bullock
- Diagnostic and Therapeutic Services, Bristol, UK.
| | - L J Bruce
- Bristol Institute for Transfusion Sciences, NHS Blood and Transplant, Bristol, UK
| | - K Ridgwell
- Diagnostic and Therapeutic Services, Bristol, UK
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Roberts LD, Ashmore T, Murray AJ, Griffin JL. Response to Comment on Lee et al. Diabetes 2015;64:2836-2846. Comment on Roberts et al. Diabetes 2015;64:471-484. Diabetes 2016; 65:e16. [PMID: 26908912 DOI: 10.2337/dbi15-0024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Lee D Roberts
- Medical Research Council Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, U.K. Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge, U.K.
| | - Tom Ashmore
- Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge, U.K
| | - Andrew J Murray
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, U.K
| | - Julian L Griffin
- Medical Research Council Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, U.K. Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge, U.K
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Nitric Oxide-cGMP Signaling Stimulates Erythropoiesis through Multiple Lineage-Specific Transcription Factors: Clinical Implications and a Novel Target for Erythropoiesis. PLoS One 2016; 11:e0144561. [PMID: 26727002 PMCID: PMC4699757 DOI: 10.1371/journal.pone.0144561] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 11/19/2015] [Indexed: 11/19/2022] Open
Abstract
Much attention has been directed to the physiological effects of nitric oxide (NO)-cGMP signaling, but virtually nothing is known about its hematologic effects. We reported for the first time that cGMP signaling induces human γ-globin gene expression. Aiming at developing novel therapeutics for anemia, we examined here the hematologic effects of NO-cGMP signaling in vivo and in vitro. We treated wild-type mice with NO to activate soluble guanylate cyclase (sGC), a key enzyme of cGMP signaling. Compared to untreated mice, NO-treated mice had higher red blood cell counts and total hemoglobin but reduced leukocyte counts, demonstrating that when activated, NO-cGMP signaling exerts hematopoietic effects on multiple types of blood cells in vivo. We next generated mice which overexpressed rat sGC in erythroid and myeloid cells. The forced expression of sGCs activated cGMP signaling in both lineage cells. Compared with non-transgenic littermates, sGC mice exhibited hematologic changes similar to those of NO-treated mice. Consistently, a membrane-permeable cGMP enhanced the differentiation of hematopoietic progenitors toward erythroid-lineage cells but inhibited them toward myeloid-lineage cells by controlling multiple lineage-specific transcription factors. Human γ-globin gene expression was induced at low but appreciable levels in sGC mice carrying the human β-globin locus. Together, these results demonstrate that NO-cGMP signaling is capable of stimulating erythropoiesis in both in vitro and vivo settings by controlling the expression of multiple lineage-specific transcription factors, suggesting that cGMP signaling upregulates erythropoiesis at the level of gene transcription. The NO-cGMP signaling axis may constitute a novel target to stimulate erythropoiesis in vivo.
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Curtis KJ, O’Brien KA, Tanner RJ, Polkey JI, Minnion M, Feelisch M, Polkey MI, Edwards LM, Hopkinson NS. Acute Dietary Nitrate Supplementation and Exercise Performance in COPD: A Double-Blind, Placebo-Controlled, Randomised Controlled Pilot Study. PLoS One 2015; 10:e0144504. [PMID: 26698120 PMCID: PMC4689520 DOI: 10.1371/journal.pone.0144504] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 11/18/2015] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Dietary nitrate supplementation can enhance exercise performance in healthy people, but it is not clear if it is beneficial in COPD. We investigated the hypotheses that acute nitrate dosing would improve exercise performance and reduce the oxygen cost of submaximal exercise in people with COPD. METHODS We performed a double-blind, placebo-controlled, cross-over single dose study. Subjects were randomised to consume either nitrate-rich beetroot juice (containing 12.9 mmoles nitrate) or placebo (nitrate-depleted beetroot juice) 3 hours prior to endurance cycle ergometry, performed at 70% of maximal workload assessed by a prior incremental exercise test. After a minimum washout period of 7 days the protocol was repeated with the crossover beverage. RESULTS 21 subjects successfully completed the study (age 68 ± 7 years; BMI 25.2 ± 5.5 kg/m2; FEV1 percentage predicted 50.1 ± 21.6%; peak VO2 18.0 ± 5.9 ml/min/kg). Resting diastolic blood pressure fell significantly with nitrate supplementation compared to placebo (-7 ± 8 mmHg nitrate vs. -1 ± 8 mmHg placebo; p = 0.008). Median endurance time did not differ significantly; nitrate 5.65 (3.90-10.40) minutes vs. placebo 6.40 (4.01-9.67) minutes (p = 0.50). However, isotime oxygen consumption (VO2) was lower following nitrate supplementation (16.6 ± 6.0 ml/min/kg nitrate vs. 17.2 ± 6.0 ml/min/kg placebo; p = 0.043), and consequently nitrate supplementation caused a significant lowering of the amplitude of the VO2-percentage isotime curve. CONCLUSIONS Acute administration of oral nitrate did not enhance endurance exercise performance; however the observation that beetroot juice caused reduced oxygen consumption at isotime suggests that further investigation of this treatment approach is warranted, perhaps targeting a more hypoxic phenotype. TRIAL REGISTRATION ISRCTN Registry ISRCTN66099139.
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Affiliation(s)
- Katrina J. Curtis
- NIHR Respiratory Biomedical Research Unit, Royal Brompton & Harefield NHS Trust and Imperial College, London, United Kingdom
| | - Katie A. O’Brien
- Centre of Human & Aerospace Physiological Sciences, King’s College London, London, United Kingdom
| | - Rebecca J. Tanner
- NIHR Respiratory Biomedical Research Unit, Royal Brompton & Harefield NHS Trust and Imperial College, London, United Kingdom
| | - Juliet I. Polkey
- NIHR Respiratory Biomedical Research Unit, Royal Brompton & Harefield NHS Trust and Imperial College, London, United Kingdom
| | - Magdalena Minnion
- Faculty of Medicine, Clinical and Experimental Sciences, University of Southampton, and Southampton NIHR Respiratory Biomedical Research Unit, Southampton General Hospital, Southampton, United Kingdom
| | - Martin Feelisch
- Faculty of Medicine, Clinical and Experimental Sciences, University of Southampton, and Southampton NIHR Respiratory Biomedical Research Unit, Southampton General Hospital, Southampton, United Kingdom
| | - Michael I. Polkey
- NIHR Respiratory Biomedical Research Unit, Royal Brompton & Harefield NHS Trust and Imperial College, London, United Kingdom
| | - Lindsay M. Edwards
- Centre of Human & Aerospace Physiological Sciences, King’s College London, London, United Kingdom
| | - Nicholas S. Hopkinson
- NIHR Respiratory Biomedical Research Unit, Royal Brompton & Harefield NHS Trust and Imperial College, London, United Kingdom
- * E-mail:
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Ashmore T, Roberts LD, Morash AJ, Kotwica AO, Finnerty J, West JA, Murfitt SA, Fernandez BO, Branco C, Cowburn AS, Clarke K, Johnson RS, Feelisch M, Griffin JL, Murray AJ. Nitrate enhances skeletal muscle fatty acid oxidation via a nitric oxide-cGMP-PPAR-mediated mechanism. BMC Biol 2015; 13:110. [PMID: 26694920 PMCID: PMC4688964 DOI: 10.1186/s12915-015-0221-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 12/10/2015] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Insulin sensitivity in skeletal muscle is associated with metabolic flexibility, including a high capacity to increase fatty acid (FA) oxidation in response to increased lipid supply. Lipid overload, however, can result in incomplete FA oxidation and accumulation of potentially harmful intermediates where mitochondrial tricarboxylic acid cycle capacity cannot keep pace with rates of β-oxidation. Enhancement of muscle FA oxidation in combination with mitochondrial biogenesis is therefore emerging as a strategy to treat metabolic disease. Dietary inorganic nitrate was recently shown to reverse aspects of the metabolic syndrome in rodents by as yet incompletely defined mechanisms. RESULTS Herein, we report that nitrate enhances skeletal muscle FA oxidation in rodents in a dose-dependent manner. We show that nitrate induces FA oxidation through a soluble guanylate cyclase (sGC)/cGMP-mediated PPARβ/δ- and PPARα-dependent mechanism. Enhanced PPARβ/δ and PPARα expression and DNA binding induces expression of FA oxidation enzymes, increasing muscle carnitine and lowering tissue malonyl-CoA concentrations, thereby supporting intra-mitochondrial pathways of FA oxidation and enhancing mitochondrial respiration. At higher doses, nitrate induces mitochondrial biogenesis, further increasing FA oxidation and lowering long-chain FA concentrations. Meanwhile, nitrate did not affect mitochondrial FA oxidation in PPARα(-/-) mice. In C2C12 myotubes, nitrate increased expression of the PPARα targets Cpt1b, Acadl, Hadh and Ucp3, and enhanced oxidative phosphorylation rates with palmitoyl-carnitine; however, these changes in gene expression and respiration were prevented by inhibition of either sGC or protein kinase G. Elevation of cGMP, via the inhibition of phosphodiesterase 5 by sildenafil, also increased expression of Cpt1b, Acadl and Ucp3, as well as CPT1B protein levels, and further enhanced the effect of nitrate supplementation. CONCLUSIONS Nitrate may therefore be effective in the treatment of metabolic disease by inducing FA oxidation in muscle.
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Affiliation(s)
- Tom Ashmore
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Lee D Roberts
- Department of Biochemistry, University of Cambridge, Cambridge, UK
- MRC-Human Nutrition Research, University of Cambridge, Cambridge, UK
| | - Andrea J Morash
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Aleksandra O Kotwica
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - John Finnerty
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - James A West
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Steven A Murfitt
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Bernadette O Fernandez
- Faculty of Medicine, Clinical & Experimental Sciences, University of Southampton, Southampton, UK
| | - Cristina Branco
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Andrew S Cowburn
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Kieran Clarke
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, UK
| | - Randall S Johnson
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Martin Feelisch
- Faculty of Medicine, Clinical & Experimental Sciences, University of Southampton, Southampton, UK
| | - Julian L Griffin
- Department of Biochemistry, University of Cambridge, Cambridge, UK
- MRC-Human Nutrition Research, University of Cambridge, Cambridge, UK
| | - Andrew J Murray
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK.
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Marsch E, Theelen TL, Janssen BJA, Briede JJ, Haenen GR, Senden JMG, van Loon LJC, Poeze M, Bierau J, Gijbels MJ, Daemen MJAP, Sluimer JC. The effect of prolonged dietary nitrate supplementation on atherosclerosis development. Atherosclerosis 2015; 245:212-21. [PMID: 26724532 DOI: 10.1016/j.atherosclerosis.2015.11.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 11/13/2015] [Accepted: 11/26/2015] [Indexed: 12/29/2022]
Abstract
BACKGROUND Short term dietary nitrate or nitrite supplementation has nitric oxide (NO)-mediated beneficial effects on blood pressure and inflammation and reduces mitochondrial oxygen consumption, possibly preventing hypoxia. As these processes are implicated in atherogenesis, dietary nitrate was hypothesized to prevent plaque initiation, hypoxia and inflammation. AIMS Study prolonged nitrate supplementation on atherogenesis, hypoxia and inflammation in low density lipoprotein receptor knockout mice (LDLr(-/-)). METHODS LDLr(-/-) mice were administered sodium-nitrate or equimolar sodium-chloride in drinking water alongside a western-type diet for 14 weeks to induce atherosclerosis. Plasma nitrate, nitrite and hemoglobin-bound nitric oxide were measured by chemiluminescence and electron parametric resonance, respectively. RESULTS Plasma nitrate levels were elevated after 14 weeks of nitrate supplementation (NaCl: 40.29 ± 2.985, NaNO3: 78.19 ± 6.837, p < 0.0001). However, prolonged dietary nitrate did not affect systemic inflammation, hematopoiesis, erythropoiesis and plasma cholesterol levels, suggesting no severe side effects. Surprisingly, neither blood pressure, nor atherogenesis were altered. Mechanistically, plasma nitrate and nitrite were elevated after two weeks (NaCl: 1.0 ± 0.2114, NaNO3: 3.977 ± 0.7371, p < 0.0001), but decreased over time (6, 10 and 14 weeks). Plasma nitrite levels even reached baseline levels at 14 weeks (NaCl: 0.7188 ± 0.1072, NaNO3: 0.9723 ± 0.1279 p = 0.12). Also hemoglobin-bound NO levels were unaltered after 14 weeks. This compensation was not due to altered eNOS activity or conversion into peroxynitrite and other RNI, suggesting reduced nitrite formation or enhanced nitrate/nitrite clearance. CONCLUSION Prolonged dietary nitrate supplementation resulted in compensation of nitrite and NO levels and did not affect atherogenesis or exert systemic side effects.
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Affiliation(s)
- Elke Marsch
- Department Pathology, CARIM, MUMC, Maastricht, The Netherlands
| | | | - Ben J A Janssen
- Department Pharmacology, CARIM, Maastricht University, Maastricht, The Netherlands
| | - Jacco J Briede
- Department Toxicogenomics, Maastricht University, Maastricht, The Netherlands
| | - Guido R Haenen
- Department Toxicology, Maastricht University, Maastricht, The Netherlands
| | - Joan M G Senden
- NUTRIM, School for Nutrition, Toxicology and Metabolism, MUMC, Maastricht, The Netherlands
| | - Lucas J C van Loon
- NUTRIM, School for Nutrition, Toxicology and Metabolism, MUMC, Maastricht, The Netherlands
| | - Martijn Poeze
- Department Surgery/Intensive Care Medicine, MUMC, Maastricht, The Netherlands
| | - Jörgen Bierau
- Department of Clinical Genetics, MUMC, Maastricht, The Netherlands
| | - Marion J Gijbels
- Department Pathology, CARIM, MUMC, Maastricht, The Netherlands; Department Molecular Genetics, CARIM, Maastricht University, Maastricht, The Netherlands; Department Medical Biochemistry, AMC, Amsterdam, The Netherlands
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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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