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Yadav N, Chaudhary V, Saraswathy KN, Devi NK. Vitamin intake in obesity and hypertension: A population-based study from Haryana, North India. CLINICAL EPIDEMIOLOGY AND GLOBAL HEALTH 2022. [DOI: 10.1016/j.cegh.2022.101178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Laflamme DP. Key nutrients important in the management of canine myxomatous mitral valve disease and heart failure. J Am Vet Med Assoc 2022; 260:S61-S70. [PMID: 36191141 DOI: 10.2460/javma.22.07.0319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The most common cause of heart failure in dogs is myxomatous mitral valve disease (MMVD), which accounts for approximately 75% of canine heart disease cases and is especially common in smaller dogs. Although low-sodium diets have been recommended for humans with heart diseases for decades, there is little evidence to support this practice in dogs. In recent years, however, it has become clear that other nutrients are important to heart health. Dogs with heart disease secondary to MMVD experience patterns of metabolic changes that include decreased mitochondrial energy metabolism and ATP availability, with increased oxidative stress and inflammation. These changes occur early in disease and progress with worsening heart disease. Key nutrients that may support normal function and address these changes include omega-3 fatty acids, medium-chain triglycerides, magnesium, antioxidants including vitamin E and taurine, and the amino acids methionine and lysine. The long-chain omega-3 fatty acids provide anti-inflammatory, antithrombotic, and other benefits. Medium-chain fatty acids and ketones derived from medium-chain triglycerides provide an alternative energy source for cardiac mitochondria and help reduce free radical production. Magnesium supports mitochondrial function, normal cardiac rhythm, and provides other benefits. Both vitamin E and taurine counter oxidative stress, and taurine also has direct cardiac benefits. Dogs with MMVD have reduced plasma methionine. Methionine and lysine are important for carnitine production as well as other functions. This article reviews the evidence supporting the functions and benefits of these and other nutrients in MMVD and other cardiac conditions.
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Li Q. Metabolic Reprogramming, Gut Dysbiosis, and Nutrition Intervention in Canine Heart Disease. Front Vet Sci 2022; 9:791754. [PMID: 35242837 PMCID: PMC8886228 DOI: 10.3389/fvets.2022.791754] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 01/05/2022] [Indexed: 12/15/2022] Open
Abstract
This review provides a state-of-the-art overview on recent advances in systems biology in canine cardiac disease, with a focus on our current understanding of bioenergetics and amino acid metabolism in myxomatous mitral valve disease (MMVD). Cross-species comparison is drawn to highlight the similarities between human and canine heart diseases. The adult mammalian heart exhibits a remarkable metabolic flexibility and shifts its energy substrate preference according to different physiological and pathological conditions. The failing heart suffers up to 40% ATP deficit and is compared to an engine running out of fuel. Bioenergetics and metabolic readaptations are among the major research topics in cardiac research today. Myocardial energy metabolism consists of three interconnected components: substrate utilization, oxidative phosphorylation, and ATP transport and utilization. Any disruption or uncoupling of these processes can result in deranged energy metabolism leading to heart failure (HF). The review describes the changes occurring in each of the three components of energy metabolism in MMVD and HF. It also provides an overview on the changes in circulating and myocardial glutathione, taurine, carnitines, branched-chain amino acid catabolism and tryptophan metabolic pathways. In addition, the review summarizes the potential role of the gut microbiome in MMVD and HF. As our knowledge and understanding in these molecular and metabolic processes increase, it becomes possible to use nutrition to address these changes and to slow the progression of the common heart diseases in dogs.
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Wang J, Deng Y, Zou X, Luo H, Jose PA, Fu C, Yang J, Zeng C. Long-term low salt diet increases blood pressure by activation of the renin-angiotensin and sympathetic nervous systems. Clin Exp Hypertens 2018; 41:739-746. [PMID: 30451012 DOI: 10.1080/10641963.2018.1545850] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Background The aim of this study was to investigate the effect of long-term low salt diet on blood pressure and its underlying mechanisms.Methods Male Sprague-Dawley (SD) rats were divided into normal salt diet group (0.4%) and low salt diet group (0.04%). Blood pressure was measured with the non-invasive tail-cuff method. The contractile response of isolated mesenteric arteries was measured using a small vessel myograph. The effects on renal function of the intrarenal arterial infusion of candesartan (10 μg/kg/min), an angiotensin II receptor type 1 (AT1R) antagonist, were also measured. The expressions of renal AT1R and mesenteric arterial α1A, α1B, and α1D adrenergic receptors were quantified by immunoblotting. Plasma levels of angiotensin II were also measured.Results Systolic blood pressure was significantly increased after 8 weeks of low salt diet. There were no obvious differences in the renal structure between the low and normal salt diet groups. However, the plasma angiotensin II levels and renal AT1R expression were higher in low than normal salt diet group. The intrarenal arterial infusion of candesartan increased urine flow and sodium excretion to a greater extent in the low than normal salt diet group. The expressions of α1A and α1D, but not α1B, adrenergic receptors, and phenylephrine-induced contraction were increased in mesenteric arteries from the low salt, relative to the normal salt diet group.Conclusion Activation of the renin-angiotensin and sympathetic nervous systems may be involved in the pathogenesis of long-term low salt diet-induced hypertension.
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Affiliation(s)
- Jialiang Wang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, P.R. China
| | - Yi Deng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, P.R. China
| | - Xue Zou
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, P.R. China
| | - Hao Luo
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, P.R. China
| | - Pedro A Jose
- Division of Renal Diseases & Hypertension, Departments of Medicine and Pharmacology/Physiology, The George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Chunjiang Fu
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, P.R. China
| | - Jian Yang
- Department of Clinical Nutrition, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, P.R. China
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, P.R. China
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He L, Liu YJ, Zheng T, Tan ZJ. Effect of high-salt diet on health: Relationship with intestinal microflora. Shijie Huaren Xiaohua Zazhi 2018; 26:143-149. [DOI: 10.11569/wcjd.v26.i3.143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Salt is the most basic and commonly used seasoning agent in daily diet. It is an important part of all kinds of food and plays a vital role in food preparation and preservation. People are increasingly in pursuit of a healthy diet to reduce the incidence of dietary-related diseases and to improve their health. Salt intake and related diseases have become the focus of research, and salt intake is considered the main factor for a healthy diet. This paper reviews the progress in research of the effect of high-salt diet on health with regard to intestinal microbiota, metabolic pathogenicity, and epidemiological investigation, and other aspects of salt consumption. Cardiovascular, endocrine, and other chronic diseases have been associated with high salt diet. A better understanding of the effect of high salt intake on health can improve the prevention and treatment of chronic diseases and provide new ideas for the development of scientific diet programs.
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Affiliation(s)
- Lu He
- Department of Microbiology, Hunan University of Chinese Medicine, Changsha 410208, Hunan Province, China
| | - You-Jia Liu
- Department of Microbiology, Hunan University of Chinese Medicine, Changsha 410208, Hunan Province, China
| | - Tao Zheng
- Department of Microbiology, Hunan University of Chinese Medicine, Changsha 410208, Hunan Province, China
| | - Zhou-Jin Tan
- Department of Microbiology, Hunan University of Chinese Medicine, Changsha 410208, Hunan Province, China
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Abstract
PURPOSE OF REVIEW Hypertension, which is present in about one quarter of the world's population, is responsible for about 41% of the number one cause of death - cardiovascular disease. Not included in these statistics is the effect of sodium intake on blood pressure, even though an increase or a marked decrease in sodium intake can increase blood pressure. This review deals with the interaction of gut microbiota and the kidney with genetics and epigenetics in the regulation of blood pressure and salt sensitivity. RECENT FINDINGS The abundance of the gut microbes, Firmicutes and Bacteroidetes, is associated with increased blood pressure in several models of hypertension, including the spontaneously hypertensive and Dahl salt-sensitive rats. Decreasing gut microbiota by antibiotics can increase or decrease blood pressure that is influenced by genotype. The biological function of probiotics may also be a consequence of epigenetic modification, related, in part, to microRNA. Products of the fermentation of nutrients by gut microbiota can influence blood pressure by regulating expenditure of energy, intestinal metabolism of catecholamines, and gastrointestinal and renal ion transport, and thus, salt sensitivity. SUMMARY The beneficial or deleterious effect of gut microbiota on blood pressure is a consequence of several variables, including genetics, epigenetics, lifestyle, and intake of antibiotics. These variables may influence the ultimate level of blood pressure and control of hypertension.
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Effects of high and low salt intake on left ventricular remodeling after myocardial infarction in normotensive rats. ACTA ACUST UNITED AC 2015; 9:77-85. [DOI: 10.1016/j.jash.2014.11.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Revised: 11/26/2014] [Accepted: 11/30/2014] [Indexed: 12/16/2022]
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Gildea JJ, Lahiff DT, Van Sciver RE, Weiss RS, Shah N, McGrath HE, Schoeffel CD, Jose PA, Carey RM, Felder RA. A linear relationship between the ex-vivo sodium mediated expression of two sodium regulatory pathways as a surrogate marker of salt sensitivity of blood pressure in exfoliated human renal proximal tubule cells: the virtual renal biopsy. Clin Chim Acta 2013; 421:236-42. [PMID: 23454474 DOI: 10.1016/j.cca.2013.02.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 01/14/2013] [Accepted: 02/21/2013] [Indexed: 12/30/2022]
Abstract
BACKGROUND Salt sensitivity (SS) of blood pressure (BP) affects 25% of adults, shares comorbidity with hypertension, and has no convenient diagnostic test. We tested the hypothesis that urine-derived exfoliated renal proximal tubule cells (RPTCs) could diagnose the degree of an individual's SS of BP. METHODS Subjects were selected who had their SS of BP determined 5 y prior to this study (salt-sensitive: ≥7 mm Hg increase in mean arterial pressure (MAP) following transition from a random weekly diet of low (10 mmol/day) to high (300 mmol/day) sodium (Na(+)) intake, N=4; inverse salt-sensitive (ISS): ≥7 mm Hg increase in MAP transitioning from a high to low Na(+) diet, N=3, and salt-resistant (SR): <7 mm Hg change in MAP transitioned on either diet, N=5). RPTC responses to 2 independent Na(+) transport pathways were measured. RESULTS There was a negative correlation between the degree of SS and dopamine-1 receptor (D1R) plasma membrane recruitment (y=-0.0107x+0.68 relative fluorescent units (RFU), R(2)=0.88, N=12, P<0.0001) and angiotensin II-stimulated intracellular Ca(++) (y=-0.0016x+0.0336, R(2)=0.7112, P<0.001, N=10) concentration over baseline. CONCLUSIONS Isolating RPTCs from urine provides a personalized cell-based diagnostic test of SS index that offers advantages over a 2-week controlled diet with respect to cost and patient compliance. Furthermore, the linear relationship between the change in MAP and response to 2 Na(+) regulatory pathways suggests that an individual's RPTC response to intracellular Na(+) is personalized and predictive.
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Affiliation(s)
- John J Gildea
- University of Virginia, Charlottesville, VA 22903, United States
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Shao W, Seth DM, Prieto MC, Kobori H, Navar LG. Activation of the renin-angiotensin system by a low-salt diet does not augment intratubular angiotensinogen and angiotensin II in rats. Am J Physiol Renal Physiol 2013; 304:F505-14. [PMID: 23303412 DOI: 10.1152/ajprenal.00587.2012] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In angiotensin II (ANG II) infusion hypertension, there is an augmentation of intratubular angiotensinogen (AGT) and ANG II leading to increased urinary AGT and ANG II excretion rates associated with tissue injury. However, the changes in urinary AGT and ANG II excretion rates and markers of renal injury during physiologically induced stimulation of the renin-angiotensin system (RAS) by a low-salt diet remain unclear. Male Sprague-Dawley rats received a low-salt diet (0.03% NaCl; n = 6) and normal-salt diet (0.3% NaCl, n = 6) for 13 days. Low-salt diet rats had markedly higher plasma renin activity and plasma ANG II levels. Kidney cortex renin mRNA, kidney AGT mRNA, and AGT immunoreactivity were not different; however, medullary renin mRNA, kidney renin content, and kidney ANG II levels were significantly elevated by the low-salt diet. Kidney renin immunoreactivity was also markedly increased in juxtaglomerular apparati and in cortical and medullary collecting ducts. Urinary AGT excretion rates and urinary ANG II excretion rates were not augmented by the low-salt diet. The low-salt diet caused mild renal fibrosis in glomeruli and the tubulointerstitium, but no other signs of kidney injury were evident. These results indicate that, in contrast to the response in ANG II infusion hypertension, the elevated plasma and intrarenal ANG II levels caused by physiological stimulation of RAS are not reflected by increased urinary AGT or ANG II excretion rates or the development of renal injury.
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Affiliation(s)
- Weijian Shao
- Dept. of Physiology, SL39, Tulane Univ. Health Sciences Center, 1430 Tulane Ave., New Orleans, LA 70112, USA.
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Juraschek SP, Guallar E, Appel LJ, Miller ER. Effects of vitamin C supplementation on blood pressure: a meta-analysis of randomized controlled trials. Am J Clin Nutr 2012; 95:1079-88. [PMID: 22492364 PMCID: PMC3325833 DOI: 10.3945/ajcn.111.027995] [Citation(s) in RCA: 178] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 02/14/2012] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND In observational studies, increased vitamin C intake, vitamin C supplementation, and higher blood concentrations of vitamin C are associated with lower blood pressure (BP). However, evidence for blood pressure-lowering effects of vitamin C in clinical trials is inconsistent. OBJECTIVE The objective was to conduct a systematic review and meta-analysis of clinical trials that examined the effects of vitamin C supplementation on BP. DESIGN We searched Medline, EMBASE, and Central databases from 1966 to 2011. Prespecified inclusion criteria were as follows: 1) use of a randomized controlled trial design; 2) trial reported effects on systolic BP (SBP) or diastolic BP (DBP) or both; 3) trial used oral vitamin C and concurrent control groups; and 4) trial had a minimum duration of 2 wk. BP effects were pooled by random-effects models, with trials weighted by inverse variance. RESULTS Twenty-nine trials met eligibility criteria for the primary analysis. The median dose was 500 mg/d, the median duration was 8 wk, and trial sizes ranged from 10 to 120 participants. The pooled changes in SBP and DBP were -3.84 mm Hg (95% CI: -5.29, -2.38 mm Hg; P < 0.01) and -1.48 mm Hg (95% CI: -2.86, -0.10 mm Hg; P = 0.04), respectively. In trials in hypertensive participants, corresponding reductions in SBP and DBP were -4.85 mm Hg (P < 0.01) and -1.67 mm Hg (P = 0.17). After the inclusion of 9 trials with imputed BP effects, BP effects were attenuated but remained significant. CONCLUSIONS In short-term trials, vitamin C supplementation reduced SBP and DBP. Long-term trials on the effects of vitamin C supplementation on BP and clinical events are needed.
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Affiliation(s)
- Stephen P Juraschek
- Johns Hopkins School of Medicine, Johns Hopkins Bloomberg School of Public Health, and Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD 21205, USA
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Pointer MA, Daumerie G, Bridges L, Yancey S, Howard K, Davis W, Huang P, Loscalzo J. Physiological stress increases renal injury in eNOS-knockout mice. Hypertens Res 2011; 35:318-24. [PMID: 22170389 DOI: 10.1038/hr.2011.185] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
African Americans have a fourfold greater likelihood of developing end-stage renal disease (ESRD) compared with Caucasians. It has been proposed that the increased prevalence may be explained by non-traditional factors such as environmental stress and psychosocial factors. In this study, we used infrequent running to exhaustion as a physiological stressor to mimic real life experiences, such walking up stairs when an elevator is malfunctioning or running to catch a bus, to study its effect on renal injury in a hypertensive mouse model (endothelial nitric oxide synthase-deficient mice; eNOS(-/-)). This model has previously been shown to have renal injury comparable to that observed in African Americans. The effect of physiological stress on renal injury was examined in the setting of low (0.12%), control (0.45%) and high (8%) dietary salt. Following bouts of physiological stress, eNOS(-/-) mice had significantly greater interstitial inflammation compared with unstressed eNOS(-/-) mice (two-way analysis of variance (2-ANOVA), Holm-Sidak; P<0.01). Interestingly, eNOS(-/-) mice on a high-salt diet had greater interstitial inflammation compared with similarly stressed eNOS(-/-) mice on a low- or control-salt diet (2-ANOVA, Holm-Sidak; P<0.03). These effects of stress were independent of systolic blood pressure (141±7, 143±4, and 158±8 vs. 141±4, 138±5, 150±4 mm Hg; end of study vs. baseline, respectively). There was no significant effect of stress or dietary salt on renal injury in control wild-type mice (eNOS(+)/(+)). These data demonstrate that physiological stress exacerbates the renal injury associated with hypertension and that high-salt compounds this effect of stress. These results provide support for the idea that psychosocial and environmental factors contribute to the increased prevalence of ESRD in hypertensive African Americans.
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Affiliation(s)
- Mildred A Pointer
- Department of Biology, Julius L. Chambers Biomedical Biotechnology Research Institute, North Carolina Central University, Durham, NC 27707, USA.
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ROS and RNS signaling in heart disorders: could antioxidant treatment be successful? OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2011; 2011:293769. [PMID: 21912722 PMCID: PMC3170796 DOI: 10.1155/2011/293769] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 05/30/2011] [Accepted: 06/02/2011] [Indexed: 11/29/2022]
Abstract
There is not too much success in the antioxidant treatment of heart deceases in humans. However a new approach is now developed that suggests that depending on their structures and concentrations antioxidants can exhibit much more complicated functions in many pathological disorders. It is now well established that physiological free radicals superoxide and nitric oxide together with their derivatives hydrogen peroxide and peroxynitrite (all are named reactive oxygen species (ROS) and reactive nitrogen species (RNS)) play a more important role in heart diseases through their signaling functions. Correspondingly this work is dedicated to the consideration of damaging signaling by ROS and RNS in various heart and vascular disorders: heart failure (congestive heart failure or CHF), left ventricular hypertrophy (LVH), coronary heart disease, cardiac arrhythmias, and so forth. It will be demonstrated that ROS overproduction (oxidative stress) is a main origin of the transformation of normal physiological signaling processes into the damaging ones. Furthermore the favorable effects of low/moderate oxidative stress through preconditioning mechanisms in ischemia/reperfusion will be considered. And in the last part we will discuss the possibility of efficient application of antioxidants and enzyme/gene inhibitors for the regulation of damaging ROS signaling in heart disorders.
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Traber MG, Stevens JF. Vitamins C and E: beneficial effects from a mechanistic perspective. Free Radic Biol Med 2011; 51:1000-13. [PMID: 21664268 PMCID: PMC3156342 DOI: 10.1016/j.freeradbiomed.2011.05.017] [Citation(s) in RCA: 508] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 05/13/2011] [Accepted: 05/17/2011] [Indexed: 02/07/2023]
Abstract
The mechanistic properties of two dietary antioxidants that are required by humans, vitamins C and E, are discussed relative to their biological effects. Vitamin C (ascorbic acid) is an essential cofactor for α-ketoglutarate-dependent dioxygenases. Examples are prolyl hydroxylases, which play a role in the biosynthesis of collagen and in down-regulation of hypoxia-inducible factor (HIF)-1, a transcription factor that regulates many genes responsible for tumor growth, energy metabolism, and neutrophil function and apoptosis. Vitamin C-dependent inhibition of the HIF pathway may provide alternative or additional approaches for controlling tumor progression, infections, and inflammation. Vitamin E (α-tocopherol) functions as an essential lipid-soluble antioxidant, scavenging hydroperoxyl radicals in a lipid milieu. Human symptoms of vitamin E deficiency suggest that its antioxidant properties play a major role in protecting erythrocyte membranes and nervous tissues. As an antioxidant, vitamin C provides protection against oxidative stress-induced cellular damage by scavenging of reactive oxygen species, by vitamin E-dependent neutralization of lipid hydroperoxyl radicals, and by protecting proteins from alkylation by electrophilic lipid peroxidation products. These bioactivities bear relevance to inflammatory disorders. Vitamin C also plays a role in the function of endothelial nitric oxide synthase (eNOS) by recycling the eNOS cofactor, tetrahydrobiopterin, which is relevant to arterial elasticity and blood pressure regulation. Evidence from plants supports a role for vitamin C in the formation of covalent adducts with electrophilic secondary metabolites. Mechanism-based effects of vitamin C and E supplementation on biomarkers and on clinical outcomes from randomized, placebo-controlled trials are emphasized in this review.
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Affiliation(s)
- Maret G Traber
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA.
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Huang A, Yan C, Suematsu N, Cuevas A, Yang YM, Kertowidjojo E, Hintze TH, Kaley G, Sun D. Impaired flow-induced dilation of coronary arterioles of dogs fed a low-salt diet: roles of ANG II, PKC, and NAD(P)H oxidase. Am J Physiol Heart Circ Physiol 2010; 299:H1476-83. [PMID: 20833958 DOI: 10.1152/ajpheart.01250.2009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Low-salt (LS) diet has been considered to be beneficial in the prevention and treatment of hypertension; however, it also increases plasma angiotensin (ANG) II and may cause adverse cardiovascular effects, such as endothelial dysfunction. We assessed endothelial function of coronary arterioles and vascular superoxide production, as a function of LS diet. Dogs were fed with LS (0.05% NaCl) or a normal-salt (NS, 0.65% NaCl) diet for 2 wk. There were threefold increases in plasma ANG II, associated with a 60% reduction in flow-induced dilation (FID) in coronary arterioles of LS compared with NS dogs. In vessels of NS dogs, FID was primarily mediated by nitric oxide (NO), as indicated by an eliminated FID by N(ω)-nitro-l-arginine methyl ester (l-NAME). In vessels of LS dogs, however, FID was eliminated. Administration of apocynin, a NAD(P)H oxidase inhibitor, partially restored FID and additional l-NAME eliminated FID. Generation of superoxide, measured with dihydroethidium, was significantly greater in vessels of LS than in NS dogs, which was further increased in response to ANG II or phorbol 12,13-dibutyrate, an agonist of protein kinase C (PKC). The enhanced superoxide was normalized by apocynin, losartan (a blocker of angiotensin type 1 receptor), and chelerythrine chloride (an antagonist of PKC). Western blotting indicated an upregulation of gp91(phox) and p47(phox), associated with increased expression of phosphorylated PKC in vessels of LS dogs. In separate experiments, dogs were fed simultaneously with LS and losartan (LS + Losa) for 2 wk. There was a significant increase in plasma ANG II in LS + Losa dogs, which, however, was associated with normal FID and gp91(phox) expression in coronary arterioles. In conclusion, LS led to endothelial dysfunction, as indicated by an impaired flow-induced dilation caused by decreasing NO bioavailibility, a response that involves angiotensin-induced activation of PKC that, in turn, activates vascular NAD(P)H oxidase to produce superoxide.
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Affiliation(s)
- An Huang
- Department of Physiology, New York Medical College, Valhalla, New York 10595, USA
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