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Dikalova A, Ao M, Tkachuk L, Dikalov S. Deacetylation mimetic mutation of mitochondrial SOD2 attenuates ANG II-induced hypertension by protecting against oxidative stress and inflammation. Am J Physiol Heart Circ Physiol 2024; 327:H433-H443. [PMID: 38904850 DOI: 10.1152/ajpheart.00162.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 06/11/2024] [Accepted: 06/11/2024] [Indexed: 06/22/2024]
Abstract
Almost one-half of adults have hypertension, and blood pressure is poorly controlled in a third of patients despite the use of multiple drugs, likely because of mechanisms that are not affected by current treatments. Hypertension is linked to oxidative stress; however, common antioxidants are ineffective. Hypertension is associated with inactivation of key intrinsic mitochondrial antioxidant, superoxide dismutase 2 (SOD2), due to hyperacetylation, but the role of specific SOD2 lysine residues has not been defined. Hypertension is associated with SOD2 acetylation at lysine 68, and we suggested that deacetylation mimetic mutation of K68 to arginine in SOD2 inhibits vascular oxidative stress and attenuates hypertension. To test this hypothesis, we have developed a new deacetylation mimetic SOD2-K68R mice. We performed in vivo studies in SOD2-K68R mice using angiotensin II (ANG II) model of vascular dysfunction and hypertension. ANG II infusion in wild-type mice induced vascular inflammation and oxidative stress and increased blood pressure to 160 mmHg. SOD2-K68R mutation completely prevented increase in mitochondrial superoxide, abrogated vascular oxidative stress, preserved endothelial nitric oxide production, protected vasorelaxation, and attenuated ANG II-induced hypertension. ANG II and cytokines contribute to vascular oxidative stress and hypertension. Treatment of wild-type aortas with ANG II and cytokines in organoid culture increased mitochondrial superoxide twofold, which was completely prevented in aortas isolated from SOD2-K68R mice. These data support the important role of SOD2-K68 acetylation in vascular oxidative stress and pathogenesis of hypertension. We conclude that strategies to reduce SOD2 acetylation may have therapeutic potential in the treatment of vascular dysfunction and hypertension.NEW & NOTEWORTHY Essential hypertension is associated with hyperacetylation of key mitochondrial antioxidant SOD2; however, the pathophysiological role of SOD2 acetylation has not been defined. Our animal study of angiotensin II hypertension model shows that deacetylation mimetic SOD2-K68R mutation prevents pathogenic increase in vascular mitochondrial superoxide, abrogates vascular oxidative stress, preserves endothelial nitric oxide, protects endothelial-dependent vasorelaxation, and attenuates hypertension. These data support the important role of SOD2-K68 acetylation in vascular oxidative stress and the pathogenesis of hypertension.
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Affiliation(s)
- Anna Dikalova
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Mingfang Ao
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Liliya Tkachuk
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Sergey Dikalov
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States
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Dikalova A, Mayorov V, Xiao L, Panov A, Amarnath V, Zagol-Ikapitte I, Vergeade A, Ao M, Yermalitsky V, Nazarewicz RR, Boutaud O, Lopez MG, Billings FT, Davies S, Roberts LJ, Harrison DG, Dikalov S. Mitochondrial Isolevuglandins Contribute to Vascular Oxidative Stress and Mitochondria-Targeted Scavenger of Isolevuglandins Reduces Mitochondrial Dysfunction and Hypertension. Hypertension 2020; 76:1980-1991. [PMID: 33012204 DOI: 10.1161/hypertensionaha.120.15236] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hypertension remains a major health problem in Western Societies, and blood pressure is poorly controlled in a third of patients despite use of multiple drugs. Mitochondrial dysfunction contributes to hypertension, and mitochondria-targeted agents can potentially improve treatment of hypertension. We have proposed that mitochondrial oxidative stress produces reactive dicarbonyl lipid peroxidation products, isolevuglandins, and that scavenging of mitochondrial isolevuglandins improves vascular function and reduces hypertension. To test this hypothesis, we have studied the accumulation of mitochondrial isolevuglandins-protein adducts in patients with essential hypertension and Ang II (angiotensin II) model of hypertension using mass spectrometry and Western blot analysis. The therapeutic potential of targeting mitochondrial isolevuglandins was tested by the novel mitochondria-targeted isolevuglandin scavenger, mito2HOBA. Mitochondrial isolevuglandins in arterioles from hypertensive patients were 250% greater than in arterioles from normotensive subjects, and ex vivo mito2HOBA treatment of arterioles from hypertensive subjects increased deacetylation of a key mitochondrial antioxidant, SOD2 (superoxide dismutase 2). In human aortic endothelial cells stimulated with Ang II plus TNF (tumor necrosis factor)-α, mito2HOBA reduced mitochondrial superoxide and cardiolipin oxidation, a specific marker of mitochondrial oxidative stress. In Ang II-infused mice, mito2HOBA diminished mitochondrial isolevuglandins-protein adducts, raised Sirt3 (sirtuin 3) mitochondrial deacetylase activity, reduced vascular superoxide, increased endothelial nitric oxide, improved endothelium-dependent relaxation, and attenuated hypertension. Mito2HOBA preserved mitochondrial respiration, protected ATP production, and reduced mitochondrial permeability pore opening in Ang II-infused mice. These data support the role of mitochondrial isolevuglandins in endothelial dysfunction and hypertension. We conclude that scavenging of mitochondrial isolevuglandins may have therapeutic potential in treatment of vascular dysfunction and hypertension.
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Affiliation(s)
- Anna Dikalova
- From the Vanderbilt University Medical Center, Nashville, TN (A.D., L.X., V.A., I.Z.-I., A.V., M.A., V.Y., R.R.N., O.B., M.G.L., F.T.B., S. Davies, L.J.R., D.G.H., S. Dikalov)
| | | | - Liang Xiao
- From the Vanderbilt University Medical Center, Nashville, TN (A.D., L.X., V.A., I.Z.-I., A.V., M.A., V.Y., R.R.N., O.B., M.G.L., F.T.B., S. Davies, L.J.R., D.G.H., S. Dikalov)
| | - Alexander Panov
- Scientific Centre for Family Health and Human Reproduction Problems, Irkutsk, Russian Federation (A.P.)
| | - Venkataraman Amarnath
- From the Vanderbilt University Medical Center, Nashville, TN (A.D., L.X., V.A., I.Z.-I., A.V., M.A., V.Y., R.R.N., O.B., M.G.L., F.T.B., S. Davies, L.J.R., D.G.H., S. Dikalov)
| | - Irene Zagol-Ikapitte
- From the Vanderbilt University Medical Center, Nashville, TN (A.D., L.X., V.A., I.Z.-I., A.V., M.A., V.Y., R.R.N., O.B., M.G.L., F.T.B., S. Davies, L.J.R., D.G.H., S. Dikalov)
| | - Aurelia Vergeade
- From the Vanderbilt University Medical Center, Nashville, TN (A.D., L.X., V.A., I.Z.-I., A.V., M.A., V.Y., R.R.N., O.B., M.G.L., F.T.B., S. Davies, L.J.R., D.G.H., S. Dikalov)
| | - Mingfang Ao
- From the Vanderbilt University Medical Center, Nashville, TN (A.D., L.X., V.A., I.Z.-I., A.V., M.A., V.Y., R.R.N., O.B., M.G.L., F.T.B., S. Davies, L.J.R., D.G.H., S. Dikalov)
| | - Valery Yermalitsky
- From the Vanderbilt University Medical Center, Nashville, TN (A.D., L.X., V.A., I.Z.-I., A.V., M.A., V.Y., R.R.N., O.B., M.G.L., F.T.B., S. Davies, L.J.R., D.G.H., S. Dikalov)
| | - Rafal R Nazarewicz
- From the Vanderbilt University Medical Center, Nashville, TN (A.D., L.X., V.A., I.Z.-I., A.V., M.A., V.Y., R.R.N., O.B., M.G.L., F.T.B., S. Davies, L.J.R., D.G.H., S. Dikalov)
| | - Olivier Boutaud
- From the Vanderbilt University Medical Center, Nashville, TN (A.D., L.X., V.A., I.Z.-I., A.V., M.A., V.Y., R.R.N., O.B., M.G.L., F.T.B., S. Davies, L.J.R., D.G.H., S. Dikalov)
| | - Marcos G Lopez
- From the Vanderbilt University Medical Center, Nashville, TN (A.D., L.X., V.A., I.Z.-I., A.V., M.A., V.Y., R.R.N., O.B., M.G.L., F.T.B., S. Davies, L.J.R., D.G.H., S. Dikalov)
| | - Frederic T Billings
- From the Vanderbilt University Medical Center, Nashville, TN (A.D., L.X., V.A., I.Z.-I., A.V., M.A., V.Y., R.R.N., O.B., M.G.L., F.T.B., S. Davies, L.J.R., D.G.H., S. Dikalov)
| | - Sean Davies
- From the Vanderbilt University Medical Center, Nashville, TN (A.D., L.X., V.A., I.Z.-I., A.V., M.A., V.Y., R.R.N., O.B., M.G.L., F.T.B., S. Davies, L.J.R., D.G.H., S. Dikalov)
| | - L Jackson Roberts
- From the Vanderbilt University Medical Center, Nashville, TN (A.D., L.X., V.A., I.Z.-I., A.V., M.A., V.Y., R.R.N., O.B., M.G.L., F.T.B., S. Davies, L.J.R., D.G.H., S. Dikalov)
| | - David G Harrison
- From the Vanderbilt University Medical Center, Nashville, TN (A.D., L.X., V.A., I.Z.-I., A.V., M.A., V.Y., R.R.N., O.B., M.G.L., F.T.B., S. Davies, L.J.R., D.G.H., S. Dikalov)
| | - Sergey Dikalov
- From the Vanderbilt University Medical Center, Nashville, TN (A.D., L.X., V.A., I.Z.-I., A.V., M.A., V.Y., R.R.N., O.B., M.G.L., F.T.B., S. Davies, L.J.R., D.G.H., S. Dikalov)
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Dikalov SI, Dikalova AE. Crosstalk Between Mitochondrial Hyperacetylation and Oxidative Stress in Vascular Dysfunction and Hypertension. Antioxid Redox Signal 2019; 31:710-721. [PMID: 30618267 PMCID: PMC6708267 DOI: 10.1089/ars.2018.7632] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Significance: Vascular dysfunction plays a key role in the development of arteriosclerosis, heart disease, and hypertension, which causes one-third of deaths worldwide. Vascular oxidative stress and metabolic disorders contribute to vascular dysfunction, leading to impaired vasorelaxation, vascular hypertrophy, fibrosis, and aortic stiffening. Mitochondria are critical in the regulation of metabolic and antioxidant functions; therefore, mitochondria-targeted treatments could be beneficial. Recent Advances: Vascular dysfunction is crucial in hypertension pathophysiology and exhibits bidirectional relationship. Metabolic disorders and oxidative stress contribute to the pathogenesis of vascular dysfunction and hypertension, which are associated with mitochondrial impairment and hyperacetylation. Mitochondrial deacetylase Sirtuin 3 (Sirt3) is critical in the regulation of metabolic and antioxidant functions. Clinical studies show that cardiovascular disease risk factors reduce Sirt3 level and Sirt3 declines with age, paralleling the increased incidence of cardiovascular disease and hypertension. An imbalance between mitochondrial acetylation and reduced Sirt3 activity contributes to mitochondrial dysfunction and oxidative stress. We propose that mitochondrial hyperacetylation drives a vicious cycle between metabolic disorders and mitochondrial oxidative stress, promoting vascular dysfunction and hypertension. Critical Issues: The mechanisms of mitochondrial dysfunction are still obscure in human hypertension. Mitochondrial hyperacetylation and oxidative stress contribute to mitochondrial dysfunction; however, regulation of mitochondrial acetylation, the role of GCN5L1 (acetyl-CoA-binding protein promoting acetyltransferase protein acetylation) acetyltransferase, Sirt3 deacetylase, and acetylation of specific proteins require further investigations. Future Directions: There is an urgent need to define molecular mechanisms and the pathophysiological role of mitochondrial hyperacetylation, identify novel pharmacological targets, and develop therapeutic approaches to reduce this phenomenon.
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Affiliation(s)
- Sergey I Dikalov
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Anna E Dikalova
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
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Mayorov V, Uchakin P, Amarnath V, Panov AV, Bridges CC, Uzhachenko R, Zackert B, Moore CS, Davies S, Dikalova A, Dikalov S. Targeting of reactive isolevuglandins in mitochondrial dysfunction and inflammation. Redox Biol 2019; 26:101300. [PMID: 31437812 PMCID: PMC6831880 DOI: 10.1016/j.redox.2019.101300] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 08/09/2019] [Accepted: 08/14/2019] [Indexed: 01/09/2023] Open
Abstract
Inflammation is a major cause of morbidity and mortality in Western societies. Despite use of multiple drugs, both chronic and acute inflammation still represent major health burdens. Inflammation produces highly reactive dicarbonyl lipid peroxidation products such as isolevuglandins which covalently modify and cross-link proteins via lysine residues. Mitochondrial dysfunction has been associated with inflammation; however, its molecular mechanisms and pathophysiological role are still obscure. We hypothesized that inflammation-induced isolevuglandins contribute to mitochondrial dysfunction and mortality. To test this hypothesis, we have (a) investigated the mitochondrial dysfunction in response to synthetic 15-E2-isolevuglandin (IsoLG) and its adducts; (b) developed a new mitochondria-targeted scavenger of isolevuglandins by conjugating 2-hydroxybenzylamine to the lipophilic cation triphenylphosphonium, (4-(4-aminomethyl)-3-hydroxyphenoxy)butyl)-triphenylphosphonium (mito2HOBA); (c) tested if mito2HOBA protects from mitochondrial dysfunction and mortality using a lipopolysaccharide model of inflammation. Acute exposure to either IsoLG or IsoLG adducts with lysine, ethanolamine or phosphatidylethanolamine inhibits mitochondrial respiration and attenuates Complex I activity. Complex II function was much more resistant to IsoLG. We confirmed that mito2HOBA markedly accumulates in isolated mitochondria and it is highly reactive with IsoLGs. To test the role of mitochondrial IsoLGs, we studied the therapeutic potential of mito2HOBA in lipopolysaccharide mouse model of sepsis. Mito2HOBA supplementation in drinking water (0.1 g/L) to lipopolysaccharide treated mice increased survival by 3-fold, improved complex I-mediated respiration, and histopathological analyses supported mito2HOBA-mediated protection of renal cortex from cell injury. These data support the role of mitochondrial IsoLG in mitochondrial dysfunction and inflammation. We conclude that reducing mitochondrial IsoLGs may be a promising therapeutic target in inflammation and conditions associated with mitochondrial oxidative stress and dysfunction.
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Affiliation(s)
| | - Peter Uchakin
- Mercer University School of Medicine, Macon, GA, USA
| | | | - Alexander V Panov
- Institute of Molecular Biology & Biophysics, Novosibirsk, Russian Federation
| | | | | | - Bill Zackert
- Vanderbilt University Medical Center, Nashville, TN, USA
| | | | - Sean Davies
- Vanderbilt University Medical Center, Nashville, TN, USA
| | - Anna Dikalova
- Vanderbilt University Medical Center, Nashville, TN, USA
| | - Sergey Dikalov
- Vanderbilt University Medical Center, Nashville, TN, USA.
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Interactions between the Cyclooxygenase Metabolic Pathway and the Renin-Angiotensin-Aldosterone Systems: Their Effect on Cardiovascular Risk, from Theory to the Clinical Practice. BIOMED RESEARCH INTERNATIONAL 2018; 2018:7902081. [PMID: 30386795 PMCID: PMC6189683 DOI: 10.1155/2018/7902081] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 09/10/2018] [Indexed: 02/07/2023]
Abstract
Coronary artery disease (CAD) and stroke are the most common and serious long-term complications of hypertension. Acetylsalicylic acid (ASA) significantly reduces their incidence and cardiovascular mortality. The RAAS activation plays an important role in pathogenesis of CVD, resulting in increased vascular resistance, proliferation of vascular-smooth-muscle-cells, and cardiac hypertrophy. Drugs acting on the renin-angiotensin-aldosterone system (RAAS) are demonstrated to reduce cardiovascular events in population with cardiovascular disease (CVD). The cyclooxygenase inhibitors limit the beneficial effect of RAAS-inhibitors, which in turn may be important in subjects with hypertension, CAD, and congestive heart failure. These observations apply to most of nonsteroidal anti-inflammatory drugs and ASA at high doses. Nevertheless, there is no strong evidence confirming presence of similar effects of cardioprotective ASA doses. The benefit of combined therapy with low-doses of ASA is-in some cases-significantly higher than that of monotherapy. So far, the significance of ASA in optimizing the pharmacotherapy remains not fully established. A better understanding of its influence on the particular CVD should contribute to more precise identification of patients in whom benefits of ASA outweigh the complication risk. This brief review summarizes the data regarding usefulness and safety of the ASA combination with drugs acting directly on the RAAS.
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Abstract
PURPOSE OF REVIEW In 1954 Harman proposed the free radical theory of aging, and in 1972 he suggested that mitochondria are both the source and the victim of toxic free radicals. Interestingly, hypertension is an age-associated disease and clinical data show that by age 70, 70% of the population has hypertension and this is accompanied by oxidative stress. Antioxidant therapy, however, is not currently available and common antioxidants such as ascorbate and vitamin E are ineffective in preventing hypertension. The present review focuses on the molecular mechanisms of mitochondrial oxidative stress and the therapeutic potential of targeting mitochondria in hypertension. RECENT FINDINGS Over the past several years, we have shown that the mitochondria become dysfunctional in hypertension and have defined a novel role of mitochondrial superoxide radicals in this disease. We have shown that genetic manipulation of mitochondrial antioxidant enzyme superoxide dismutase affects blood pressure, and have developed mitochondria-targeted therapies such as mitochondrial superoxide dismutase mimetics that effectively lower blood pressure. However, the specific mechanism of mitochondrial oxidative stress in hypertension remains unclear. Recent animal and clinical studies have demonstrated several hormonal, metabolic, inflammatory, and environmental pathways contributing to mitochondrial dysfunction and oxidative stress. SUMMARY Nutritional supplements, calorie restriction, and life style change are the most effective preventive strategies to improve mitochondrial function and reduce mitochondrial oxidative stress. Aging associated mitochondrial dysfunction, however, reduces the efficacy of these strategies. Therefore, we propose that new classes of mitochondria-targeted antioxidants can provide a high therapeutic potential to improve endothelial function and reduce hypertension.
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Antihypertensive effect of mitochondria-targeted proxyl nitroxides. Redox Biol 2014; 4:355-62. [PMID: 25677087 PMCID: PMC4326181 DOI: 10.1016/j.redox.2014.12.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 12/22/2014] [Indexed: 01/18/2023] Open
Abstract
Superoxide (O2-•) has been implicated in the pathogenesis of many human diseases including hypertension. Mitochondria-targeted superoxide scavenger mitoTEMPO reduces blood pressure; however, the structure–functional relationships in antihypertensive effect of mitochondria-targeted nitroxides remain unclear. The nitroxides are known to undergo bioreduction into hydroxylamine derivatives which reacts with O2-• with much lower rate. The nitroxides of pyrrolidine series (proxyls) are much more resistant to bioreduction compared to TEMPOL derivatives suggesting that mitochondria-targeted proxyls can be effective antioxidants with antihypertensive activity. In this work we have designed and studied two new pyrrolidine mitochondria targeted nitroxides: 3-[2-(triphenyphosphonio)acetamido]- and 3-[2-(triphenyphosphonio) acetamidomethyl]-2,2,5,5-tetramethylpyrrolidine-1-oxyl (mCP2) and (mCP1). These new mitochondria targeted nitroxides have 3- to 7-fold lower rate constants of the reaction with O2-• compared with mitoTEMPO; however, the cellular bioreduction of mCP1 and mCP2 was 3- and 2-fold slower. As a consequence incubation with cells afforded much higher intracellular concentration of mCP1 and mCP2 nitroxides compared to mitoTEMPO nitroxide. This has compensated for the difference in the rate of O2-• scavenging and all nitroxides similarly protected mitochondrial respiration in H2O2 treated endothelial cells. Treatment of hypertensive mice with mCP1 and mCP2 (1.4 mg/kg/day) after onset of angiotensin II-induced hypertension significantly reduced blood pressure to 133±5 mmHg and 129±6 mmHg compared to 163±5 mmHg in mice infused with angiotensin II alone. mCP1 and mCP2 reduced vascular O2-• and prevented decrease of endothelial nitric oxide production. These data indicate that resistance to bioreduction play significant role in antioxidant activity of nitroxides. Studies of nitroxide analogs such as mCP1 and mCP2 may help in optimization of chemical structure of mitochondria-targeted nitroxides for improved efficacy and pharmacokinetics of these drugs in treatment of hypertension and many other conditions including atherosclerosis, diabetes and degenerative neurological disorders in which mitochondrial oxidative stress seems to play a role. Nitroxides bioreduction into hydroxylamine can reduce their antioxidant properties. Mitochondria-targeted proxyls are more resistant to bioreduction vs mitoTEMPO. Intracellular concentration of mCP1 and mCP2 nitroxides is higher vs mitoTEMPO. mCP1 and mCP2 diminished vascular superoxide and reduced hypertension.
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de Faria Poloni J, Chapola H, Feltes BC, Bonatto D. The importance of sphingolipids and reactive oxygen species in cardiovascular development. Biol Cell 2014; 106:167-81. [PMID: 24678717 DOI: 10.1111/boc.201400008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 03/24/2014] [Indexed: 02/01/2023]
Abstract
The heart is the first organ in the embryo to form. Its structural and functional complexity is the result of a thorough developmental program, where sphingolipids play an important role in cardiogenesis, heart maturation, angiogenesis, the regulation of vascular tone and vessel permeability. Sphingolipids are necessary for signal transduction and membrane microdomain formation. In addition, recent evidence suggests that sphingolipid metabolism is directly interconnected to the modulation of oxidative stress. However, cardiovascular development is highly sensitive to excessive reactive species production, and disturbances in sphingolipid metabolism can lead to abnormal development and cardiac disease. Therefore, in this review, we address the molecular link between sphingolipids and oxidative stress, connecting these pathways to cardiovascular development and cardiovascular disease.
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Affiliation(s)
- Joice de Faria Poloni
- Centro de Biotecnologia da Universidade Federal do Rio Grande do Sul, Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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Kuo KL, Hung SC, Lee TS, Tarng DC. Iron sucrose accelerates early atherogenesis by increasing superoxide production and upregulating adhesion molecules in CKD. J Am Soc Nephrol 2014; 25:2596-606. [PMID: 24722448 DOI: 10.1681/asn.2013080838] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
High-dose intravenous iron supplementation is associated with adverse cardiovascular outcomes in patients with CKD, but the underlying mechanism is unknown. Our study investigated the causative role of iron sucrose in leukocyte-endothelium interactions, an index of early atherogenesis, and subsequent atherosclerosis in the mouse remnant kidney model. We found that expression levels of intracellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) and adhesion of U937 cells increased in iron-treated human aortic endothelial cells through upregulated NADPH oxidase (NOx) and NF-κB signaling. We then measured mononuclear-endothelial adhesion and atherosclerotic lesions of the proximal aorta in male C57BL/6 mice with subtotal nephrectomy, male apolipoprotein E-deficient (ApoE(-/-)) mice with uninephrectomy, and sham-operated mice subjected to saline or parenteral iron loading. Iron sucrose significantly increased tissue superoxide production, expression of tissue cell adhesion molecules, and endothelial adhesiveness in mice with subtotal nephrectomy. Moreover, iron sucrose exacerbated atherosclerosis in the aorta of ApoE(-/-) mice with uninephrectomy. In patients with CKD, intravenous iron sucrose increased circulating mononuclear superoxide production, expression of soluble adhesion molecules, and mononuclear-endothelial adhesion compared with healthy subjects or untreated patients. In summary, iron sucrose aggravated endothelial dysfunction through NOx/NF-κB/CAM signaling, increased mononuclear-endothelial adhesion, and exacerbated atherosclerosis in mice with remnant kidneys. These results suggest a novel causative role for therapeutic iron in cardiovascular complications in patients with CKD.
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Affiliation(s)
- Ko-Lin Kuo
- Department and Institute of Physiology, and Division of Nephrology, Taipei Tzuchi Hospital, The Buddhist Tzuchi Medical Foundation, Taipei, Taiwan
| | - Szu-Chun Hung
- Division of Nephrology, Taipei Tzuchi Hospital, The Buddhist Tzuchi Medical Foundation, Taipei, Taiwan
| | - Tzong-Shyuan Lee
- Department and Institute of Physiology, and Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan; and
| | - Der-Cherng Tarng
- Department and Institute of Physiology, and Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan; Division of Nephrology, Department of Medicine and Immunology Research Centre, Taipei Veterans General Hospital, Taipei, Taiwan
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Abstract
Based on mosaic theory, hypertension is a multifactorial disorder that develops because of genetic, environmental, anatomical, adaptive neural, endocrine, humoral, and hemodynamic factors. It has been recently proposed that oxidative stress may contribute to all of these factors and production of reactive oxygen species (ROS) play an important role in the development of hypertension. Previous studies focusing on the role of vascular NADPH oxidases provided strong support of this concept. Although mitochondria represent one of the most significant sources of cellular ROS generation, the regulation of mitochondrial ROS generation in the cardiovascular system and its pathophysiological role in hypertension are much less understood. In this review, the role of mitochondrial oxidative stress in the pathophysiology of hypertension and cross talk between angiotensin II signaling, pathways involved in mechanotransduction, NADPH oxidases, and mitochondria-derived ROS are considered. The possible benefits of therapeutic strategies that have the potential to attenuate mitochondrial oxidative stress for the prevention/treatment of hypertension are also discussed.
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Affiliation(s)
- Sergey I Dikalov
- Division of Clinical Pharmacology, Free Radicals in Medicine Core, Vanderbilt University Medical Center, Nashville, Tennessee; and
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Kuo KL, Hung SC, Lin YP, Tang CF, Lee TS, Lin CP, Tarng DC. Intravenous ferric chloride hexahydrate supplementation induced endothelial dysfunction and increased cardiovascular risk among hemodialysis patients. PLoS One 2012; 7:e50295. [PMID: 23227165 PMCID: PMC3515606 DOI: 10.1371/journal.pone.0050295] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 10/22/2012] [Indexed: 01/31/2023] Open
Abstract
Background The association between intravenous (IV) iron administration and outcomes in hemodialysis (HD) patients is still debated. Therefore, this study was aimed to assess the relationship between the IV administration of ferric chloride hexahydrate (Atofen®) and cardiovascular (CV) outcome and the interaction between iron-induced oxidative stress and endothelial dysfunction in chronic HD patients. Methodology/Principal Findings A cohort of 1239 chronic HD patients was recruited. In a follow-up of 12 months, Kaplan-Meier survival curves showed that higher doses of IV Atofen associated with higher risks for CV events and deaths in HD patients. In multivariate Cox models, compared to no iron supplementation, IV Atofen administration was an independent predictor for CV events and overall mortality. However, the nature of the observational cohort study possibly bears selection bias. We further found that IV Atofen enhanced the superoxide production of mononuclear cells (MNCs), the levels of circulating soluble adhesion molecules, and the adhesion of MNCs to human aortic endothelial cells (HAECs). In vitro experiments showed that Atofen increased the expression of intracellular cell adhesion molecule-1 and vascular cell adhesion molecule-1 in HAECs and aggravated the endothelial adhesiveness in a dose-dependent manner. These iron-induced changes were significantly attenuated by the co-treatment of HAECs with N-acetylcysteine and inhibitors of NADPH oxidase, nuclear factor κB, and activator protein-1. Conclusion A cumulative dose of IV Atofen >800 mg within 6 months was associated with an adverse CV outcome and a higher mortality among chronic HD patients. The detrimental effects of IV iron supplementation were partly due to the increased oxidative stress and induction of MNC adhesion to endothelial cells, a pivotal index of early atherogenesis.
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Affiliation(s)
- Ko-Lin Kuo
- Department and Institute of Physiology, National Yang-Ming University, Taipei, Taiwan
- School of Medicine, Tzu Chi University, Hualien, Taiwan
- Division of Nephrology, Buddhist Tzu Chi General Hospital, Taipei Branch, Taipei, Taiwan
| | - Szu-Chun Hung
- School of Medicine, Tzu Chi University, Hualien, Taiwan
- Division of Nephrology, Buddhist Tzu Chi General Hospital, Taipei Branch, Taipei, Taiwan
| | - Yao-Ping Lin
- Division of Nephrology, Department of Medicine and Immunology Centre, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Ching-Fang Tang
- Division of Nephrology, Department of Medicine and Immunology Centre, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Tzong-Shyuan Lee
- Department and Institute of Physiology, National Yang-Ming University, Taipei, Taiwan
| | - Chih-Pei Lin
- Department of Biotechnology and Laboratory Science in Medicine and Institute of Biotechnology in Medicine, National Yang-Ming University, Taipei, Taiwan
- Division of General Laboratory, Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
- * E-mail: (C-PL); (D-CT)
| | - Der-Cherng Tarng
- Department and Institute of Physiology, National Yang-Ming University, Taipei, Taiwan
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan
- Division of Nephrology, Department of Medicine and Immunology Centre, Taipei Veterans General Hospital, Taipei, Taiwan
- * E-mail: (C-PL); (D-CT)
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12
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Izumiyama K, Osanai T, Sagara S, Yamamoto Y, Itoh T, Sukekawa T, Nishizaki F, Magota K, Okumura K. Estrogen attenuates coupling factor 6-induced salt-sensitive hypertension and cardiac systolic dysfunction in mice. Hypertens Res 2012; 35:539-46. [PMID: 22258022 DOI: 10.1038/hr.2011.232] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In male coupling factor 6 (CF6)-overexpressing transgenic (TG) mice, a high-salt diet induces hypertension and cardiac systolic dysfunction with excessive reactive oxygen species generation. However, the role of gender in CF6-mediated pathophysiology is unknown. We investigated the effects of ovariectomy and estrogen replacement on hypertension, cardiac dysfunction and Rac1 activity, which activates radical generation and the mineralocorticoid receptor, in female TG mice. Fifteen-week-old male and female TG and wild-type (WT) mice were fed a normal- or high-salt diet for 60 weeks. Systolic and diastolic blood pressures were higher in the TG mice fed a high-salt diet than in those fed a normal-salt diet at 20-60 weeks in males but only at 60 weeks in females. The blood pressure elevation under high-salt diet conditions was concomitant with a decrease in left ventricular fractional shortening. In the WT mice, neither blood pressure nor cardiac systolic function was influenced by a high-salt diet. In the female TG mice, bilateral ovariectomy induced hypertension with cardiac systolic dysfunction 8 weeks after the initiation of a high-salt diet. The ratios of Rac1 bound to guanosine triphosphate (Rac1-GTP) to total Rac1 in the heart and kidneys were increased in the ovariectomized TG mice, and estrogen replacement abolished the CF6-mediated pathophysiology induced under the high-salt diet conditions. The overexpression of CF6 induced salt-sensitive hypertension, complicated by systolic cardiac dysfunction, but its onset was delayed in females. Estrogen has an important role in the regulation of CF6-mediated pathophysiology, presumably via the downregulation of Rac1.
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Affiliation(s)
- Kei Izumiyama
- Department of Cardiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
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13
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Dendooven A, Ishola DA, Nguyen TQ, Van der Giezen DM, Kok RJ, Goldschmeding R, Joles JA. Oxidative stress in obstructive nephropathy. Int J Exp Pathol 2010; 92:202-10. [PMID: 20804541 DOI: 10.1111/j.1365-2613.2010.00730.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Unilateral ureteric obstruction (UUO) is one of the most commonly applied rodent models to study the pathophysiology of renal fibrosis. This model reflects important aspects of inflammation and fibrosis that are prominent in human kidney diseases. In this review, we present an overview of the factors contributing to the pathophysiology of UUO, highlighting the role of oxidative stress.
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Affiliation(s)
- Amélie Dendooven
- Department of Pathology, University Medical Center, Utrecht, The Netherlands
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14
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Dong Y, Zhang M, Wang S, Liang B, Zhao Z, Liu C, Wu M, Choi HC, Lyons TJ, Zou MH. Activation of AMP-activated protein kinase inhibits oxidized LDL-triggered endoplasmic reticulum stress in vivo. Diabetes 2010; 59:1386-96. [PMID: 20299472 PMCID: PMC2874699 DOI: 10.2337/db09-1637] [Citation(s) in RCA: 159] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2009] [Accepted: 02/24/2010] [Indexed: 01/18/2023]
Abstract
OBJECTIVE The oxidation of LDLs is considered a key step in the development of atherosclerosis. How LDL oxidation contributes to atherosclerosis remains poorly defined. Here we report that oxidized and glycated LDL (HOG-LDL) causes aberrant endoplasmic reticulum (ER) stress and that the AMP-activated protein kinase (AMPK) suppressed HOG-LDL-triggered ER stress in vivo. RESEARCH DESIGN AND METHODS ER stress markers, sarcoplasmic/endoplasmic reticulum Ca(2+) ATPase (SERCA) activity and oxidation, and AMPK activity were monitored in cultured bovine aortic endothelial cells (BAECs) exposed to HOG-LDL or in isolated aortae from mice fed an atherogenic diet. RESULTS Exposure of BAECs to clinically relevant concentrations of HOG-LDL induced prolonged ER stress and reduced SERCA activity but increased SERCA oxidation. Chronic administration of Tempol (a potent antioxidant) attenuated both SERCA oxidation and aberrant ER stress in mice fed a high-fat diet in vivo. Likewise, AMPK activation by pharmacological (5'-aminoimidazole-4-carboxymide-1-beta-d-ribofuranoside, metformin, and statin) or genetic means (adenoviral overexpression of constitutively active AMPK mutants) significantly mitigated ER stress and SERCA oxidation and improved the endothelium-dependent relaxation in isolated mouse aortae. Finally, Tempol administration markedly attenuated impaired endothelium-dependent vasorelaxation, SERCA oxidation, ER stress, and atherosclerosis in ApoE(-/-) and ApoE(-/-)/AMPKalpha2(-/-) fed a high-fat diet. CONCLUSION We conclude that HOG-LDL, via enhanced SERCA oxidation, causes aberrant ER stress, endothelial dysfunction, and atherosclerosis in vivo, all of which are inhibited by AMPK activation.
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Affiliation(s)
- Yunzhou Dong
- Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; and
| | - Miao Zhang
- Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; and
| | - Shuangxi Wang
- Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; and
| | - Bin Liang
- Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; and
| | - Zhengxing Zhao
- Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; and
| | - Chao Liu
- Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; and
| | - Mingyuan Wu
- Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; and
| | - Hyoung Chul Choi
- Department of Pharmacology, College of Medicine, Yeungnam University, Daegu, Korea
| | - Timothy J. Lyons
- Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; and
| | - Ming-Hui Zou
- Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; and
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15
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Adam O, Hagel M, Theobald K, Böhm M, Laufs U. Inhibitory effect of estrogen on Rac1-expression in monocytes. Biochem Biophys Res Commun 2009; 386:45-9. [PMID: 19497305 DOI: 10.1016/j.bbrc.2009.05.126] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Accepted: 05/28/2009] [Indexed: 11/30/2022]
Abstract
Recruitment of circulating monocytes into the vasculature and release of reactive oxygen species (ROS) promote atherogenesis. Rac1-GTPase is an essential component of the superoxide-producing NADPH-oxidase complex. Estrogens inhibit production of vascular reactive oxygen species. Angiotensin II as well as overexpression of the constitutively active mutant RacL61 increased ROS production in monocytes. AngII-mediated ROS release was completely inhibited by overexpression of the dominant negative mutant RacN17 or treatment with 17beta-estradiol. 17beta-Estradiol reduced Rac1-expression concentration- and time-dependently and decreased basal, as well as AngII-induced Rac1 activity. The effects of 17beta-estradiol were receptor-mediated. In vivo, down-regulation of Rac1 by 17beta-estradiol was observed in human mononuclear cells of women with elevated 17beta-estradiol levels after controlled ovarian hyperstimulation. In summary, the data show that down-regulation of Rac1-GTPase contributes to the inhibition of angiotensin II-mediated superoxide release by 17beta-estradiol in monocytes.
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Affiliation(s)
- Oliver Adam
- Klinik für Innere Medizin III, Kardiologie, Angiologie und Internistische Intensivmedizin, Universitätsklinikum des Saarlandes, Homburg/Saar, D-66421 Homburg/Saar, Germany.
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16
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Barton M, Haas E, Bhattacharya I. Getting radical about obesity: new links between fat and heart disease. Arterioscler Thromb Vasc Biol 2009; 29:447-8. [PMID: 19299330 DOI: 10.1161/atvbaha.108.181529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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17
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Oppermann M, Balz V, Adams V, Dao VTV, Bas M, Suvorava T, Kojda G. Pharmacological induction of vascular extracellular superoxide dismutase expression in vivo. J Cell Mol Med 2008; 13:1271-8. [PMID: 19320775 PMCID: PMC4496141 DOI: 10.1111/j.1582-4934.2008.00627.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Pentaerythritol tetranitrate (PETN) treatment reduces progression of atherosclerosis and endothelial dysfunction and decreases oxidation of low-density lipoprotein (LDL) in rabbits. These effects are associated with decreased vascular superoxide production, but the underlying molecular mechanisms remain unknown. Previous studies demonstrated that endogenous nitric oxide could regulate the expression of extracellular superoxide dismutase (ecSOD) in conductance vessels in vivo. We investigated the effect of PETN and overexpression of endothelial nitric oxide synthase (eNOS++) on the expression and activity of ecSOD. C57BL/6 mice were randomized to receive placebo or increasing doses of PETN for 4 weeks and eNOS++ mice with a several fold higher endothelial-specific eNOS expression were generated. The expression of ecSOD was determined in the lung and aortic tissue by real-time PCR and Western blot. The ecSOD activity was measured using inhibition of cytochrome C reduction. There was no effect of PETN treatment or eNOS overexpression on ecSOD mRNA in the lung tissue, whereas ecSOD protein expression increased from 2.5-fold to 3.6-fold (P < 0.05) by 6 mg PETN/kg body weight (BW)/day and 60 mg PETN/kg BW/day, respectively. A similar increase was found in aortic homogenates. eNOS++ lung cytosols showed an increase of ecSOD protein level of 142 ± 10.5% as compared with transgene-negative littermates (P < 0.05), which was abolished by Nω-nitro-L-arginine treatment. In each animal group, the increase of ecSOD expression was paralleled by an increase of ecSOD activity. Increased expression and activity of microvascular ecSOD are likely induced by increased bioavailability of vascular nitric oxide. Up-regulation of vascular ecSOD may contribute to the reported antioxidative and anti-atherosclerotic effects of PETN.
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Affiliation(s)
- Marc Oppermann
- Institute for Pharmacology and Clinical Pharmacology, Heinrich-Heine-University, Duesseldorf, Germany
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18
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Wolfort RM, Stokes KY, Granger DN. CD4+ T lymphocytes mediate hypercholesterolemia-induced endothelial dysfunction via a NAD(P)H oxidase-dependent mechanism. Am J Physiol Heart Circ Physiol 2008; 294:H2619-26. [DOI: 10.1152/ajpheart.00989.2007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although hypercholesterolemia is known to impair endothelium-dependent vasodilation (EDV) long before the appearance of atherosclerotic plaques, it remains unclear whether the immune mechanisms that have been implicated in atherogenesis also contribute to the early oxidative stress and endothelial cell dysfunction elicited by hypercholesterolemia. EDV (wire myography), superoxide generation (cytochrome c reduction), and NAD(P)H oxidase mRNA expression were monitored in aortic rings from wild-type (WT) and mutant mice placed on either a normal diet or a cholesterol-enriched diet (HC) for 2 wk. WT mice on HC exhibited impaired EDV, enhanced superoxide generation, and increased expression of NAD(P)H oxidase subunit Nox-2 mRNA. The impaired EDV and increased superoxide generation induced by HC were significantly blunted in severe combined immunodeficient (SCID) mice and CD4+ T lymphocyte-deficient mice. These responses were also attenuated in HC mice genetically deficient in IFN-γ; however, adoptive transfer of WT-HC CD4+ T lymphocytes to IFN-γ-deficient recipients restored HC-induced responses. The HC-induced impaired EDV and oxidative stress were also attenuated in HC mice genetically deficient in Nox-2 (gp91 phox−/−) and in WT→gp91 phox−/−-HC chimeras. HC-induced gp91 phox mRNA expression was significantly blunted in mice deficient in CD4+ T cells or IFN-γ and was restored with adoptive transfer of WT-HC CD4+ T cells to IFN-γ-deficient recipients. These findings implicate the immune system in the early endothelial cell dysfunction associated with hypercholesterolemia and are consistent with a mechanism of impaired EDV that is mediated by CD4+ T cells and IFN-γ, acting through the generation of superoxide from vascular NAD(P)H oxidase.
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19
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C242T Polymorphism of NADPH Oxidase p22phox and Recurrence of Cardiovascular Events in Coronary Artery Disease. Arterioscler Thromb Vasc Biol 2008; 28:752-7. [DOI: 10.1161/atvbaha.107.154823] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objectives—
The common C242T polymorphism in the gene for the p22phox subunit of NADPH oxidase has been reported to be negatively associated with oxidative stress, but whether it confers prognostic information is not yet clear.
Methods and Results—
The incidence of major adverse cardiovascular events (MACE) were determined in 237 patients with coronary stenosis during a median follow-up of 7.8 years. The
p22phox
genotypes were evaluated in 213 patients (89.9%) by polymerase chain reaction and
Rsa
I. digestion. Plasma levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG), a marker of oxidative stress, were also measured. In the univariate analysis, patients with CT/TT genotypes showed reduced recurrence of cardiovascular deaths, nonfatal MI, and revascularization procedures compared with homozygous carriers of the C allele. After controlling for confounders, a significantly lower risk of new revascularization procedures (HR=0.31, 95% CI 0.12 to 0.70;
P
=0.014) remained associated with the T allele. The Kaplan–Meier analysis showed a longer survival free from fatal and nonfatal MI in carriers of T allele (
P
<0.001). The presence of the 242T allele was associated with significantly reduced plasma concentrations of 8-OHdG.
Conclusions—
The 242T allele was a predictor of lower risk of recurrence of cardiovascular events in high-risk patients and was associated with reduced systemic oxidative stress.
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20
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Ragheb A, Elbarbry F, Prasad K, Mohamed A, Ahmed MS, Shoker A. Attenuation of the development of hypercholesterolemic atherosclerosis by thymoquinone. Int J Angiol 2008; 17:186-92. [PMID: 22477447 PMCID: PMC2728923 DOI: 10.1055/s-0031-1278307] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Thymoquinone (TQ), derived from Nigella sativa seed, is an antioxidant. The present study investigated whether TQ attenuates the development of atherosclerosis, and/or reduces the serum lipid levels and oxidative stress in rabbits. New Zealand white female rabbits were assigned to four groups of six animals each: group I, control; group II, 1% cholesterol diet; group III, 1% cholesterol plus TQ (10 mg/kg/day; through a nasogastric tube) diet; and group IV, 1% cholesterol plus TQ (20 mg/kg/day; through a nasogastric tube) diet. Blood samples were collected at baseline and after four and eight weeks on the experimental diets for measurement of serum lipids, total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), TC/HDL-C ratio and oxidative stress biomarkers (malondialdehyde [MDA] and protein carbonyls). At the end of the eight weeks, the aorta was removed for the assessment of atherosclerotic changes, MDA and protein carbonyls. Group II animals developed atherosclerosis (45%±11% of the intimal surface of aorta was covered with atherosclerotic plaques), which was associated with an increase in the serum TC, TG, LDL-C, HDL-C, TC/HDL-C, MDA and protein carbonyls. In group III, TQ decreased serum TC, LDL-C, MDA and protein carbonyls by 26%, 29%, 85% and 62%, respectively, and aortic MDA by 73%, which was associated with a 40% reduction of the development of aortic atherosclerosis. The higher dose of TQ in group IV had effects similar to the lower dose (group III), except that this dose further decreased serum TG. It is concluded that TQ attenuates hypercholesterolemic atherosclerosis and this effect is associated with a decrease in serum lipids and oxidative stress.
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Affiliation(s)
- Ahmed Ragheb
- Department of Medicine, Royal University Hospital, University of Saskatchewan, Saskatoon, Saskatchewan
| | - Fawzy Elbarbry
- School of Pharmacy, Pacific University, Hillsboro, Oregon, USA
| | | | | | - Mohamed S Ahmed
- Department of Pathology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan
| | - Ahmed Shoker
- Department of Medicine, Royal University Hospital, University of Saskatchewan, Saskatoon, Saskatchewan
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21
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Li L, Frei B. Iron Chelation Inhibits NF-κB–Mediated Adhesion Molecule Expression by Inhibiting p22
phox
Protein Expression and NADPH Oxidase Activity. Arterioscler Thromb Vasc Biol 2006; 26:2638-43. [PMID: 16973969 DOI: 10.1161/01.atv.0000245820.34238.da] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Objective—
Excess iron may increase oxidative stress and play a role in vascular inflammation and atherosclerosis. Here we determined whether the iron chelator, desferrioxamine (DFO), ameliorates oxidative stress and cellular adhesion molecule expression in a murine model of local inflammation.
Methods and Results—
Dorsal air pouches were created in C57BL/6J mice by subcutaneous injection of air. DFO (100 mg/kg body weight) was injected into the air pouch once a day for two days followed immediately on the second day by lipopolysaccharide (LPS; 2.5 mg/kg body weight). The animals were euthanized 24 hours later for analysis of oxidative stress markers and adhesion molecules in air pouch tissue. LPS treatment enhanced protein levels of p22
phox
, a catalytic subunit of NADPH oxidase, and increased NADPH oxidase activity and levels of superoxide radicals and hydrogen peroxide. Furthermore, LPS activated NF-κB and increased expression of adhesion molecules. All of these inflammatory responses were strongly suppressed by DFO, but not iron-loaded DFO.
Conclusions—
Our data show that DFO inhibits LPS-induced, NADPH oxidase–mediated oxidative stress and, hence, NF-κB activation and adhesion molecule expression in a murine model of local inflammation. Iron chelation may be helpful in treating atherosclerotic vascular diseases by ameliorating oxidative stress and inflammation.
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Affiliation(s)
- Lixin Li
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331-6512, USA
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22
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Padró T, Mendieta C, Badimon L. Inflamación y arteriosclerosis. HIPERTENSION Y RIESGO VASCULAR 2005. [DOI: 10.1016/s1889-1837(05)71554-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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23
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Faxon DP, Fuster V, Libby P, Beckman JA, Hiatt WR, Thompson RW, Topper JN, Annex BH, Rundback JH, Fabunmi RP, Robertson RM, Loscalzo J. Atherosclerotic Vascular Disease Conference: Writing Group III: pathophysiology. Circulation 2004; 109:2617-25. [PMID: 15173044 DOI: 10.1161/01.cir.0000128520.37674.ef] [Citation(s) in RCA: 229] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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24
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Müller S, König I, Meyer W, Kojda G. Inhibition of vascular oxidative stress in hypercholesterolemia by eccentric isosorbide mononitrate. J Am Coll Cardiol 2004; 44:624-31. [PMID: 15358031 DOI: 10.1016/j.jacc.2004.02.062] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2003] [Revised: 02/13/2004] [Accepted: 02/17/2004] [Indexed: 11/30/2022]
Abstract
OBJECTIVES We sought to determine if the nitric oxide (NO) donor isosorbide mononitrate (ISMN) (200 mg/kg body weight/day) decreases vascular bioavailability of superoxide in atherosclerosis. BACKGROUND Vascular oxidative stress limits the bioavailability of endothelial NO and promotes atherosclerosis, while NO itself exerts antioxidative effects. It is unknown if therapeutic NO impacts on vascular oxidative stress in atherosclerosis. METHODS New Zealand white rabbits (n = 10 each group) were fed either normal chow (control), cholesterol chow (CHOL) (0.75%), or cholesterol chow enriched with ISMN (CHOL-ISMN). Rabbits were fed twice daily. After 16 weeks we used aortic segments to measure vascular superoxide (5-microM lucigenin), intimal lesion formation, and vasoreactivity to acetylcholine (ACH) and ISMN. RESULTS Plasma cholesterol increased by 40-fold in CHOL and CHOL-ISMN. The plasma concentration of ISMN in CHOL-ISMN was 1,529 +/- 447 ng/ml. Superoxide formation (control: 228 +/- 20 counts/20 min/mg) was strongly enhanced in CHOL (345 +/- 46 counts/20 min/mg, p = 0.02) but not in CHOL-ISMN (229 +/- 23 counts/20 min/mg) demonstrating antioxidative effects of eccentric ISMN in vivo. In parallel, intima-media thickness of thoracic aorta (159 +/- 4 microm in control) was reduced from 645 +/- 41 microm (CHOL) to 440 +/- 51 microm (CHOL-ISMN, p < 0.05). Likewise, eccentric ISMN partially restored vascular responses to the NO donor S-nitroso-N-acetyl-D,L-penicillamine and improved endothelium-dependent vasorelaxation. The maximal ACH relaxation increased from 26.3 +/- 9.6% in CHOL to 49.7 +/- 8.1% in CHOL-ISMN; ISMN treatment induced a moderate nitrate tolerance as evidenced by diminished ISMN-induced vasodilation. CONCLUSIONS These data suggest that eccentric ISMN can completely inhibit the increase of vascular bioavailability of superoxide and partially prevent intimal lesion formation and endothelial dysfunction in hypercholesterolemia.
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Affiliation(s)
- Senta Müller
- Institut fuer Pharmakologie und Klinische Pharmakologie, Heinrich-Heine-Universitaet, Duesseldorf, Germany
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25
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Abstract
Common conditions predisposing to atherosclerosis, such as hypercholesterolemia, hypertension, diabetes, and smoking, are associated with endothelial dysfunction. Endothelial function has largely been assessed as endothelium-dependent vasomotion, at least in part based on the assumption that impaired endothelium-dependent vasodilation also reflects the alteration of other important functions of the endothelium. An important rationale for this approach has been the observation that endothelium-derived nitric oxide (NO), a major mediator of endothelium-dependent vasodilation, has important anti-inflammatory and antithrombotic properties, ie, inhibiting leukocyte adhesion, limiting platelet adhesion and aggregation, and the expression of plasminogen activator inhibitor-1 (PAI-1), a prothrombotic protein. Accumulating data suggest that the degree of impairment of endothelium-dependent vasomotion has profound and independent prognostic implications. A common mechanism underlying endothelial dysfunction relates to increased vascular production of reactive oxygen species. Recent studies also suggest that inflammation per se and C-reactive protein in particular may directly contribute to endothelial dysfunction. These findings raise the question of whether assessment of endothelial function can be used in the clinical setting to identify patients at high risk. New insights into mechanisms of endothelial dysfunction, such as a better understanding of the regulation of important vascular sources of oxygen radicals, may lead to novel therapeutic strategies with the potential to improve prognosis.
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Affiliation(s)
- Ulf Landmesser
- Medizinische Hochschule Hannover, Abteilung Kardiologie und Angiologie, Carl Neuberg Str.1, 30625 Hannover, Germany
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26
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Abstract
Atherosclerosis is a complex disease process that affects very specific sites of the vasculature. It is recognized that hemodynamic forces are largely responsible for dictating which vascular sites are either susceptible or resistant to developing atherosclerosis. In addition, a number of systemic and local factors also modulate the pathogenesis of the disease. By studying the development of atherosclerosis in mice, investigators have gained insights into the molecular mechanisms of this disease, although studies have largely focused on a single vascular site. Here, we review those recent studies in which vascular site-specific effects on atherosclerosis were reported when more than 1 site was examined. We assess the hypothesis that regional differences in the hemodynamic profile prime the endothelial phenotype to respond distinctly to such systemic risk factors as hypercholesterolemia, genetics, immune status, gender, and oxidative stress. Because a given treatment may differentially affect the development of atherosclerotic lesions throughout the vasculature, the sites chosen for study are critically important. By accounting for the complex interplay of factors that may operate at these different sites, a more complete understanding of the overriding mechanisms that control the initiation and progression of the atherosclerotic lesion may be realized.
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Affiliation(s)
- Paul A VanderLaan
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
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27
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Abstract
This article has focused on the influence of NO. on vascular homeostasis. Vascular tone, however, is also influenced by other vasoactive factors released by the endothelium, including the endothelial-derived hyperpolarizing factors, prostacyclin, and vasoconstrictor factors. There is also abundant evidence that these factors are altered by pathophysiologic states, although the mechanisms responsible are not as well understood as they seem to be for the NO. system. There is now evidence that several endothelial-derived hyperpolarizing factors may exist. One is almost certainly the cytochrome p450 metabolite of arachidonic acid, epoxyeicosatrienoic acid (EET) [92], whereas another is likely H2O2, which stimulates potassium channel opening in a fashion similar to the EET [93]. EET has anti-inflammatory properties, whereas H2O2 may potentially enhance inflammation and promote vascular hypertrophy. Thus, two factors released by the endothelium with similar acute effects on the vascular smooth muscle may have very different long-term consequences in terms of protecting against or promoting vascular disease. During the past two decades, physicians have gained a substantial understanding of the L-arginine/eNOS/NO. pathway and how this modulates vascular reactivity. Further, physicians now are aware that this process is altered by many risk factors for atherosclerosis and have begun to understand how these disorders alter NO. production and bioavailability. These abnormalities are likely multifactorial and physicians are beginning to understand how they can be corrected. An exciting aspect of endothelial function is that it has prognostic significance above and beyond the traditional risk factors for atherosclerosis. Several studies now have shown that individuals with intact endothelial function in either the forearm or the coronary circulation have a low incidence of events during follow-up periods, whereas those individuals with abnormal endothelial function have a high incidence of major cardiovascular events [94-96]. Because of the complexity of abnormalities that underlie endothelial dysfunction, there are various therapeutic targets that may have to be addressed to improve endothelial function and ultimately improve prognosis in these individuals.
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Affiliation(s)
- David G Harrison
- Division of Cardiology, Emory University School of Medicine, 1639 Pierce Drive, Room 319 WMRB, Atlanta, GA 30322, USA.
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28
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Laufs U. Beyond lipid-lowering: effects of statins on endothelial nitric oxide. Eur J Clin Pharmacol 2003; 58:719-31. [PMID: 12634978 DOI: 10.1007/s00228-002-0556-0] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2002] [Accepted: 12/15/2002] [Indexed: 01/05/2023]
Abstract
Endothelial dysfunction is now recognised as an important process in the pathogenesis of atherosclerosis. Nitric oxide (NO) release by the endothelium regulates blood flow, inflammation and platelet aggregation, and consequently its disruption during endothelial dysfunction can decrease plaque stability and encourage the formation of atherosclerotic lesions and thrombi. Inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (statins) are often utilised in the prevention of coronary heart disease due to their efficacy at lowering lipid levels. However, statins may also prevent atherosclerotic disease by non-lipid or pleiotropic effects, for example, improving endothelial function by promoting the production of NO. There are various mechanisms whereby statins may alter NO release, such as inhibiting the production of mevalonate and important isoprenoid intermediates, thereby preventing the isoprenylation of the small GTPase Rho, which negatively regulates the expression of endothelial nitric oxide synthase (eNOS). Furthermore, statins may also increase eNOS activity via post-translational activation of the phosphatidylinositol 3-kinase/protein kinase Akt (PI3 K/Akt) pathway and/or through an interaction with the molecular chaperone heat-shock protein 90 (HSP90). Data suggest that statins may vary in their efficacy for enhancing the release of NO, and the mechanisms dictating these differences are not yet clear. By increasing NO production, statins may interfere with atherosclerotic lesion development, stabilise plaque, inhibit platelet aggregation, improve blood flow and protect against ischaemia. Therefore, the ability of statins to improve endothelial function through the release of NO may partially account for their beneficial effects at reducing the incidence of cardiovascular events.
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Affiliation(s)
- Ulrich Laufs
- Medizinische Klinik und Poliklinik der Universität des Saarlandes, Innere Medizin III, 66421, Homburg/Saar, Germany.
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Laufs U, Adam O, Strehlow K, Wassmann S, Konkol C, Laufs K, Schmidt W, Böhm M, Nickenig G. Down-regulation of Rac-1 GTPase by Estrogen. J Biol Chem 2003; 278:5956-62. [PMID: 12493759 DOI: 10.1074/jbc.m209813200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Rac1 GTPase is essential for the activation of the NAD(P)H oxidase complex and, thereby, regulates the release of reactive oxygen species (ROS) in the vessel wall. 17 beta-estradiol (E2) inhibits vascular ROS production. To elucidate the underlying molecular mechanisms we investigated the potential regulation of Rac1 by E2 in vascular smooth muscle cells. Treatment of vascular smooth muscle cells with angiotensin II as well as overexpression of the constitutively active mutant RacL61 increased ROS release as assessed by dichlorofluorescein fluorescence, whereas inhibition of Rac1 by Clostridium sordellii lethal toxin or overexpression of dominant-negative RacN17 inhibited ROS production. Treatment with E2 (100 nm) completely prevented angiotensin II-induced NAD(P)H oxidase activity and ROS production. E2 time and concentration dependently decreased angiotensin II-induced and basal Rac1 mRNA and protein expression as well as Rac1 activity. Down-regulation of Rac1 expression by E2 was mediated by inhibition of gene transcription (nuclear run-on assays), but E2 had no effect on Rac1 mRNA stability. Regulation of Rac1 was mediated by estrogen receptors since co-incubation with ICI 182.780 prevented down-regulation of Rac1. To test these observations in vivo, ovariectomized spontaneously hypertensive rats were treated with E2 or vehicle. Real-time PCR and Western blotting showed reduction of aortic Rac1 mRNA and protein by 32 and 58%, respectively. Furthermore, down-regulation of Rac1 by E2 was observed in human mononuclear cells of women with elevated E2 levels after controlled ovarian hyperstimulation. Rac1 GTPase gene-transcription and activity is regulated by 17 beta-estradiol, which may be an important molecular mechanism contributing to the cardiovascular effects of estrogens.
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Affiliation(s)
- Ulrich Laufs
- Medizinische Klinik und Poliklinik, Innere Medizin III, Universitätskliniken des Saarlandes, 66421 Homburg/Saar, Germany.
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Landmesser U, Spiekermann S, Dikalov S, Tatge H, Wilke R, Kohler C, Harrison DG, Hornig B, Drexler H. Vascular oxidative stress and endothelial dysfunction in patients with chronic heart failure: role of xanthine-oxidase and extracellular superoxide dismutase. Circulation 2002; 106:3073-8. [PMID: 12473554 DOI: 10.1161/01.cir.0000041431.57222.af] [Citation(s) in RCA: 368] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Impaired flow-dependent, endothelium-mediated vasodilation (FDD) in patients with chronic heart failure (CHF) results, at least in part, from accelerated degradation of nitric oxide by oxygen radicals. The mechanisms leading to increased vascular radical formation, however, remain unclear. Therefore, we determined endothelium-bound activities of extracellular superoxide dismutase (ecSOD), a major vascular antioxidant enzyme, and xanthine-oxidase, a potent radical producing enzyme, and their relation to FDD in patients with CHF. METHODS AND RESULTS ecSOD and xanthine-oxidase activities, released from endothelium into plasma by heparin bolus injection, were determined in 14 patients with CHF and 10 control subjects. FDD of the radial artery was measured using high-resolution ultrasound and was assessed before and after administration of the antioxidant vitamin C (25 mg/min; IA). In patients with CHF, endothelium-bound ecSOD activity was substantially reduced (5.0+/-0.7 versus 14.4+/-2.6 U x mL(-1) x min(-1); P<0.01) and closely related to FDD (r=0.61). Endothelium-bound xanthine-oxidase activity was increased by >200% (38+/-10 versus 12+/-4 nmol O2*- x microL(-1); P<0.05) and inversely related to FDD (r=-0.35) in patients with CHF. In patients with low ecSOD and high xanthine-oxidase activity, a greater benefit of vitamin C on FDD was observed, ie, the portion of FDD inhibited by radicals correlated negatively with ecSOD (r=-0.71) but positively with xanthine-oxidase (r=0.75). CONCLUSIONS These results demonstrate that both increased xanthine-oxidase and reduced ecSOD activity are closely associated with increased vascular oxidative stress in patients with CHF. This loss of vascular oxidative balance likely represents a novel mechanism contributing to endothelial dysfunction in CHF.
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Affiliation(s)
- Ulf Landmesser
- Abteilung Kardiologie und Angiologie, Medizinische Hochschule Hannover, Hannover, Germany.
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Hayden MR, Tyagi SC. Intimal redox stress: accelerated atherosclerosis in metabolic syndrome and type 2 diabetes mellitus. Atheroscleropathy. Cardiovasc Diabetol 2002; 1:3. [PMID: 12392600 PMCID: PMC140143 DOI: 10.1186/1475-2840-1-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2002] [Accepted: 09/27/2002] [Indexed: 02/07/2023] Open
Abstract
Metabolic syndrome, insulin resistance, prediabetes, and overt type 2 diabetes mellitus are associated with an accelerated atherosclerosis (atheroscleropathy). This quartet is also associated with multiple metabolic toxicities resulting in the production of reactive oxygen species. The redox stress associated with these reactive oxygen species contribute to the development, progression, and the final fate of the arterial vessel wall in prediabetic and diabetic atheroscleropathy. The prevention of morbidity and mortality of these intersecting metabolic diseases can be approached through comprehensive global risk reduction.
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Affiliation(s)
- Melvin R Hayden
- Adjunct Assistant Professor Department of Family and Community Medicine University of Missouri Columbia, Missouri, USA
| | - Suresh C Tyagi
- Assistant Professor Department of Physiology and Biophysics University of Mississippi Medical Center Jackson, Mississippi 39216-4505, USA
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