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Upanan S, Lee J, Tunau-Spencer KJ, Rajvanshi PK, Wright EC, Noguchi CT, Schechter AN. High nitrate levels in skeletal muscle contribute to nitric oxide generation via a nitrate/nitrite reductive pathway in mice that lack the nNOS enzyme. Front Physiol 2024; 15:1352242. [PMID: 38784116 PMCID: PMC11112080 DOI: 10.3389/fphys.2024.1352242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 04/05/2024] [Indexed: 05/25/2024] Open
Abstract
Introduction Nitric oxide (NO) is a vasodilator gas that plays a critical role in mitochondrial respiration and skeletal muscle function. NO is endogenously generated by NO synthases: neuronal NO synthase (nNOS), endothelial NO synthase (eNOS), or inducible NO synthase (iNOS). NO in skeletal muscle is partly generated by nNOS, and nNOS deficiency can contribute to muscular dystrophic diseases. However, we and others discovered an alternative nitrate/nitrite reductive pathway for NO generation: nitrate to nitrite to NO. We hypothesized that nitrate supplementation would increase nitrate accumulation in skeletal muscle and promote a nitrate/nitrite reductive pathway for NO production to compensate for the loss of nNOS in skeletal muscle. Methods Wild-type (WT) and genetic nNOS knockout (nNOS-/-) mice were fed normal chow (386.9 nmol/g nitrate) and subjected to three treatments: high-nitrate water (1 g/L sodium nitrate for 7 days), low-nitrate diet (46.8 nmol/g nitrate for 7 days), and low-nitrate diet followed by high-nitrate water for 7 days each. Results High-nitrate water supplementation exhibited a greater and more significant increase in nitrate levels in skeletal muscle and blood in nNOS-/- mice than in WT mice. A low-nitrate diet decreased blood nitrate and nitrite levels in both WT and nNOS-/- mice. WT and nNOS-/- mice, treated with low-nitrate diet, followed by high-nitrate water supplementation, showed a significant increase in nitrate levels in skeletal muscle and blood, analogous to the increases observed in nNOS-/- mice supplemented with high-nitrate water. In skeletal muscle of nNOS-/- mice on high-nitrate water supplementation, on low-nitrate diet, and in low-high nitrate treatment, the loss of nNOS resulted in a corresponding increase in the expression of nitrate/nitrite reductive pathway-associated nitrate transporters [sialin and chloride channel 1 (CLC1)] and nitrate/nitrite reductase [xanthine oxidoreductase (XOR)] but did not show a compensatory increase in iNOS or eNOS protein and eNOS activation activity [p-eNOS (Ser1177)]. Discussion These findings suggest that a greater increase in nitrate levels in skeletal muscle of nNOS-/- mice on nitrate supplementation results from reductive processes to increase NO production with the loss of nNOS in skeletal muscle.
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Affiliation(s)
- Supranee Upanan
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Jeeyoung Lee
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Khalid J. Tunau-Spencer
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Praveen K. Rajvanshi
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Elizabeth C. Wright
- Office of the Director, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Constance T. Noguchi
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Alan N. Schechter
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
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Bahadoran Z, Mirmiran P, Ghasemi A. Adipose organ dysfunction and type 2 diabetes: Role of nitric oxide. Biochem Pharmacol 2024; 221:116043. [PMID: 38325496 DOI: 10.1016/j.bcp.2024.116043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/07/2024] [Accepted: 02/01/2024] [Indexed: 02/09/2024]
Abstract
Adipose organ, historically known as specialized lipid-handling tissue serving as the long-term fat depot, is now appreciated as the largest endocrine organ composed of two main compartments, i.e., subcutaneous and visceral adipose tissue (AT), madding up white and beige/brown adipocytes. Adipose organ dysfunction manifested as maldistribution of the compartments, hypertrophic, hypoxic, inflamed, and insulin-resistant AT, contributes to the development of type 2 diabetes (T2D). Here, we highlight the role of nitric oxide (NO·) in AT (dys)function in relation to developing T2D. The key aspects determining lipid and glucose homeostasis in AT depend on the physiological levels of the NO· produced via endothelial NO· synthases (eNOS). In addition to decreased NO· bioavailability (via decreased expression/activity of eNOS or scavenging NO·), excessive NO· produced by inducible NOS (iNOS) in response to hypoxia and AT inflammation may be a critical interfering factor diverting NO· signaling to the formation of reactive oxygen and nitrogen species, resulting in AT and whole-body metabolic dysfunction. Pharmacological approaches boosting AT-NO· availability at physiological levels (by increasing NO· production and its stability), as well as suppression of iNOS-NO· synthesis, are potential candidates for developing NO·-based therapeutics in T2D.
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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
| | - Parvin Mirmiran
- Department of Clinical Nutrition and Dietetics, Faculty of Nutrition Sciences and Food Technology, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Asghar Ghasemi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Alharbi M, Stephan BC, Shannon OM, Siervo M. Does dietary nitrate boost the effects of caloric restriction on brain health? Potential physiological mechanisms and implications for future research. Nutr Metab (Lond) 2023; 20:45. [PMID: 37880786 PMCID: PMC10599060 DOI: 10.1186/s12986-023-00766-9] [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: 05/26/2023] [Accepted: 10/07/2023] [Indexed: 10/27/2023] Open
Abstract
Dementia is a highly prevalent and costly disease characterised by deterioration of cognitive and physical capacity due to changes in brain function and structure. Given the absence of effective treatment options for dementia, dietary and other lifestyle approaches have been advocated as potential strategies to reduce the burden of this condition. Maintaining an optimal nutritional status is vital for the preservation of brain function and structure. Several studies have recognised the significant role of nutritional factors to protect and enhance metabolic, cerebrovascular, and neurocognitive functions. Caloric restriction (CR) positively impacts on brain function via a modulation of mitochondrial efficiency, endothelial function, neuro-inflammatory, antioxidant and autophagy responses. Dietary nitrate, which serves as a substrate for the ubiquitous gasotransmitter nitric oxide (NO), has been identified as a promising nutritional intervention that could have an important role in improving vascular and metabolic brain regulation by affecting oxidative metabolism, ROS production, and endothelial and neuronal integrity. Only one study has recently tested the combined effects of both interventions and showed preliminary, positive outcomes cognitive function. This paper explores the potential synergistic effects of a nutritional strategy based on the co-administration of CR and a high-nitrate diet as a potential and more effective (than either intervention alone) strategy to protect brain health and reduce dementia risk.
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Affiliation(s)
- Mushari Alharbi
- School of Life Sciences, The University of Nottingham Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK
- Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah, 22252, Saudi Arabia
| | - Blossom Cm Stephan
- Curtin Dementia Centre of Excellence, EnAble Institute, Curtin University, Kent Street, Bentley, WA, 6102, Australia
| | - Oliver M Shannon
- Human Nutrition Research Centre, Population Health Sciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Mario Siervo
- Curtin Dementia Centre of Excellence, EnAble Institute, Curtin University, Kent Street, Bentley, WA, 6102, Australia.
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Caloric Restriction (CR) Plus High-Nitrate Beetroot Juice Does Not Amplify CR-Induced Metabolic Adaptation and Improves Vascular and Cognitive Functions in Overweight Adults: A 14-Day Pilot Randomised Trial. Nutrients 2023; 15:nu15040890. [PMID: 36839248 PMCID: PMC9962072 DOI: 10.3390/nu15040890] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 02/07/2023] [Accepted: 02/08/2023] [Indexed: 02/12/2023] Open
Abstract
Caloric restriction (CR) and dietary nitrate supplementation are nutritional interventions with pleiotropic physiological functions. This pilot study investigates the combined effects of CR and nitrate-rich beetroot juice (BRJ) on metabolic, vascular, and cognitive functions in overweight and obese middle-aged and older adults. This was a two-arm, parallel randomized clinical trial including 29 participants allocated to CR + BRJ (n = 15) or CR alone (n = 14) for 14 days. Body composition, resting energy expenditure (REE), and hand-grip strength were measured. Resting blood pressure (BP) and microvascular endothelial function were measured, and Trail-Making Test A and B were used to assess cognitive function. Salivary nitrate and nitrite, and urinary nitrate and 8-isoprostane concentrations were measured. Changes in body composition, REE, and systolic and diastolic BP were similar between the two interventions (p > 0.05). The CR + BRJ intervention produced greater changes in average microvascular flux (p = 0.03), NO-dependent endothelial activity (p = 0.02), and TMT-B cognitive scores (p = 0.012) compared to CR alone. Changes in urinary 8-isoprostane were greater in the CR + BRJ group (p = 0.02), and they were inversely associated with changes in average microvascular flux (r = -0.53, p = 0.003). These preliminary findings suggest that greater effects on vascular and cognitive functions could be achieved by combining CR with dietary nitrate supplementation.
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Keller RM, Beaver LM, Prater MC, Truong L, Tanguay RL, Stevens JF, Hord NG. Nitrate exposure reprograms hepatic amino acid and nutrient sensing pathways prior to exercise: A metabolomic and transcriptomic investigation in zebrafish (Danio rerio). Front Mol Biosci 2022; 9:903130. [PMID: 35928228 PMCID: PMC9343839 DOI: 10.3389/fmolb.2022.903130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 06/28/2022] [Indexed: 11/13/2022] Open
Abstract
Scope: Nitrate supplementation is a popular ergogenic aid that improves exercise performance by reducing oxygen consumption during exercise. We investigated the effect of nitrate exposure and exercise on metabolic pathways in zebrafish liver.Materials and methods: Fish were exposed to sodium nitrate (606.9 mg/L), or control water, for 21 days and analyzed at intervals during an exercise test. We utilized untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis and measured gene expression of 24 genes central to energy metabolism and redox signaling.Results: We observed a greater abundance of metabolites involved in endogenous nitric oxide (NO) metabolism and amino acid metabolism in nitrate-treated liver at rest, compared to rested controls. In the absence of exercise, nitrate treatment upregulated expression of genes central to nutrient sensing (pgc1a), protein synthesis (mtor) and purine metabolism (pnp5a and ampd1) and downregulated expression of genes involved in mitochondrial fat oxidation (acaca and cpt2).Conclusion: Our data support a role for sub-chronic nitrate treatment in the improvement of exercise performance, in part, by improving NO bioavailability, sparing arginine, and modulating hepatic gluconeogenesis and glycolytic capacity in the liver.
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Affiliation(s)
- Rosa M. Keller
- University of California, San Francisco, San Francisco, CA, United States
| | - Laura M. Beaver
- University of California, San Francisco, San Francisco, CA, United States
- Linus Pauling Institute, Oregon State University, Corvallis, OR, United States
| | - Mary C. Prater
- Department of Foods and Nutrition, College of Family and Consumer Sciences, University of Georgia, Athens, GA, United States
| | - Lisa Truong
- Sinnhuber Aquatic Research Laboratory and the Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR, United States
| | - Robyn L. Tanguay
- Sinnhuber Aquatic Research Laboratory and the Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR, United States
| | - Jan F. Stevens
- Linus Pauling Institute, Oregon State University, Corvallis, OR, United States
- College of Pharmacy, Oregon State University, Corvallis, OR, United States
| | - Norman G. Hord
- OU Health, Harold Hamm Diabetes Center, Department of Nutritional Sciences, College of Allied Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- *Correspondence: Norman G. Hord,
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Luk C, Haywood NJ, Bridge KI, Kearney MT. Paracrine Role of the Endothelium in Metabolic Homeostasis in Health and Nutrient Excess. Front Cardiovasc Med 2022; 9:882923. [PMID: 35557517 PMCID: PMC9086712 DOI: 10.3389/fcvm.2022.882923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 04/04/2022] [Indexed: 02/02/2023] Open
Abstract
The vascular endothelium traditionally viewed as a simple physical barrier between the circulation and tissue is now well-established as a key organ mediating whole organism homeostasis by release of a portfolio of anti-inflammatory and pro-inflammatory vasoactive molecules. Healthy endothelium releases anti-inflammatory signaling molecules such as nitric oxide and prostacyclin; in contrast, diseased endothelium secretes pro-inflammatory signals such as reactive oxygen species, endothelin-1 and tumor necrosis factor-alpha (TNFα). Endothelial dysfunction, which has now been identified as a hallmark of different components of the cardiometabolic syndrome including obesity, type 2 diabetes and hypertension, initiates and drives the progression of tissue damage in these disorders. Recently it has become apparent that, in addition to vasoactive molecules, the vascular endothelium has the potential to secrete a diverse range of small molecules and proteins mediating metabolic processes in adipose tissue (AT), liver, skeletal muscle and the pancreas. AT plays a pivotal role in orchestrating whole-body energy homeostasis and AT dysfunction, characterized by local and systemic inflammation, is central to the metabolic complications of obesity. Thus, understanding and targeting the crosstalk between the endothelium and AT may generate novel therapeutic opportunities for the cardiometabolic syndrome. Here, we provide an overview of the role of the endothelial secretome in controlling the function of AT. The endothelial-derived metabolic regulatory factors are grouped and discussed based on their physical properties and their downstream signaling effects. In addition, we focus on the therapeutic potential of these regulatory factors in treating cardiometabolic syndrome, and discuss areas of future study of potential translatable and clinical significance. The vascular endothelium is emerging as an important paracrine/endocrine organ that secretes regulatory factors in response to nutritional and environmental cues. Endothelial dysfunction may result in imbalanced secretion of these regulatory factors and contribute to the progression of AT and whole body metabolic dysfunction. As the vascular endothelium is the first responder to local nutritional changes and adipocyte-derived signals, future work elucidating the changes in the endothelial secretome is crucial to improve our understanding of the pathophysiology of cardiometabolic disease, and in aiding our development of new therapeutic strategies to treat and prevent cardiometabolic syndrome.
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Affiliation(s)
- Cheukyau Luk
- Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
| | - Natalie J Haywood
- Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
| | - Katherine I Bridge
- Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
| | - Mark T Kearney
- Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
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Walker AMN, Warmke N, Mercer B, Watt NT, Mughal R, Smith J, Galloway S, Haywood NJ, Soomro T, Griffin KJ, Wheatcroft SB, Yuldasheva NY, Beech DJ, Carmeliet P, Kearney MT, Cubbon RM. Endothelial Insulin Receptors Promote VEGF-A Signaling via ERK1/2 and Sprouting Angiogenesis. Endocrinology 2021; 162:bqab104. [PMID: 34037749 PMCID: PMC8223729 DOI: 10.1210/endocr/bqab104] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Indexed: 02/08/2023]
Abstract
Endothelial insulin receptors (Insr) promote sprouting angiogenesis, although the underpinning cellular and molecular mechanisms are unknown. Comparing mice with whole-body insulin receptor haploinsufficiency (Insr+/-) against littermate controls, we found impaired limb perfusion and muscle capillary density after inducing hind-limb ischemia; this was in spite of increased expression of the proangiogenic growth factor Vegfa. Insr+/- neonatal retinas exhibited reduced tip cell number and branching complexity during developmental angiogenesis, which was also found in separate studies of mice with endothelium-restricted Insr haploinsufficiency. Functional responses to vascular endothelial growth factor A (VEGF-A), including in vitro angiogenesis, were also impaired in aortic rings and pulmonary endothelial cells from Insr+/- mice. Human umbilical vein endothelial cells with shRNA-mediated knockdown of Insr also demonstrated impaired functional angiogenic responses to VEGF-A. VEGF-A signaling to Akt and endothelial nitric oxide synthase was intact, but downstream signaling to extracellular signal-reduced kinase 1/2 (ERK1/2) was impaired, as was VEGF receptor-2 (VEGFR-2) internalization, which is required specifically for signaling to ERK1/2. Hence, endothelial insulin receptors facilitate the functional response to VEGF-A during angiogenic sprouting and are required for appropriate signal transduction from VEGFR-2 to ERK1/2.
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Affiliation(s)
- Andrew M N Walker
- Leeds Institute of Cardiovascular and Metabolic Medicine, The University of Leeds, Leeds LS2 9JT, UK
| | - Nele Warmke
- Leeds Institute of Cardiovascular and Metabolic Medicine, The University of Leeds, Leeds LS2 9JT, UK
| | - Ben Mercer
- Leeds Institute of Cardiovascular and Metabolic Medicine, The University of Leeds, Leeds LS2 9JT, UK
| | - Nicole T Watt
- Leeds Institute of Cardiovascular and Metabolic Medicine, The University of Leeds, Leeds LS2 9JT, UK
| | - Romana Mughal
- Leeds Institute of Cardiovascular and Metabolic Medicine, The University of Leeds, Leeds LS2 9JT, UK
| | - Jessica Smith
- Leeds Institute of Cardiovascular and Metabolic Medicine, The University of Leeds, Leeds LS2 9JT, UK
| | - Stacey Galloway
- Leeds Institute of Cardiovascular and Metabolic Medicine, The University of Leeds, Leeds LS2 9JT, UK
| | - Natalie J Haywood
- Leeds Institute of Cardiovascular and Metabolic Medicine, The University of Leeds, Leeds LS2 9JT, UK
| | - Taha Soomro
- Leeds Institute of Cardiovascular and Metabolic Medicine, The University of Leeds, Leeds LS2 9JT, UK
- Imperial College Ophthalmology Research Group, Western Eye Hospital, London NW1 5QH, UK
| | - Kathryn J Griffin
- Leeds Institute of Cardiovascular and Metabolic Medicine, The University of Leeds, Leeds LS2 9JT, UK
| | - Stephen B Wheatcroft
- Leeds Institute of Cardiovascular and Metabolic Medicine, The University of Leeds, Leeds LS2 9JT, UK
| | - Nadira Y Yuldasheva
- Leeds Institute of Cardiovascular and Metabolic Medicine, The University of Leeds, Leeds LS2 9JT, UK
| | - David J Beech
- Leeds Institute of Cardiovascular and Metabolic Medicine, The University of Leeds, Leeds LS2 9JT, UK
| | - Peter Carmeliet
- Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Department of Oncology, University of Leuven, Leuven 3000, Belgium
| | - Mark T Kearney
- Leeds Institute of Cardiovascular and Metabolic Medicine, The University of Leeds, Leeds LS2 9JT, UK
| | - Richard M Cubbon
- Leeds Institute of Cardiovascular and Metabolic Medicine, The University of Leeds, Leeds LS2 9JT, UK
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Abstract
The prevalence of cardiovascular and metabolic disease coupled with kidney dysfunction is increasing worldwide. This triad of disorders is associated with considerable morbidity and mortality as well as a substantial economic burden. Further understanding of the underlying pathophysiological mechanisms is important to develop novel preventive or therapeutic approaches. Among the proposed mechanisms, compromised nitric oxide (NO) bioactivity associated with oxidative stress is considered to be important. NO is a short-lived diatomic signalling molecule that exerts numerous effects on the kidneys, heart and vasculature as well as on peripheral metabolically active organs. The enzymatic L-arginine-dependent NO synthase (NOS) pathway is classically viewed as the main source of endogenous NO formation. However, the function of the NOS system is often compromised in various pathologies including kidney, cardiovascular and metabolic diseases. An alternative pathway, the nitrate-nitrite-NO pathway, enables endogenous or dietary-derived inorganic nitrate and nitrite to be recycled via serial reduction to form bioactive nitrogen species, including NO, independent of the NOS system. Signalling via these nitrogen species is linked with cGMP-dependent and independent mechanisms. Novel approaches to restoring NO homeostasis during NOS deficiency and oxidative stress have potential therapeutic applications in kidney, cardiovascular and metabolic disorders.
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