1
|
Ungvari A, Gulej R, Csik B, Mukli P, Negri S, Tarantini S, Yabluchanskiy A, Benyo Z, Csiszar A, Ungvari Z. The Role of Methionine-Rich Diet in Unhealthy Cerebrovascular and Brain Aging: Mechanisms and Implications for Cognitive Impairment. Nutrients 2023; 15:4662. [PMID: 37960316 PMCID: PMC10650229 DOI: 10.3390/nu15214662] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 10/28/2023] [Accepted: 10/31/2023] [Indexed: 11/15/2023] Open
Abstract
As aging societies in the western world face a growing prevalence of vascular cognitive impairment and Alzheimer's disease (AD), understanding their underlying causes and associated risk factors becomes increasingly critical. A salient concern in the western dietary context is the high consumption of methionine-rich foods such as red meat. The present review delves into the impact of this methionine-heavy diet and the resultant hyperhomocysteinemia on accelerated cerebrovascular and brain aging, emphasizing their potential roles in cognitive impairment. Through a comprehensive exploration of existing evidence, a link between high methionine intake and hyperhomocysteinemia and oxidative stress, mitochondrial dysfunction, inflammation, and accelerated epigenetic aging is drawn. Moreover, the microvascular determinants of cognitive deterioration, including endothelial dysfunction, reduced cerebral blood flow, microvascular rarefaction, impaired neurovascular coupling, and blood-brain barrier (BBB) disruption, are explored. The mechanisms by which excessive methionine consumption and hyperhomocysteinemia might drive cerebromicrovascular and brain aging processes are elucidated. By presenting an intricate understanding of the relationships among methionine-rich diets, hyperhomocysteinemia, cerebrovascular and brain aging, and cognitive impairment, avenues for future research and potential therapeutic interventions are suggested.
Collapse
Affiliation(s)
- Anna Ungvari
- Department of Public Health, Semmelweis University, 1089 Budapest, Hungary
| | - Rafal Gulej
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (R.G.); (B.C.); (P.M.); (S.N.); (S.T.); (A.Y.); (A.C.); (Z.U.)
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Boglarka Csik
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (R.G.); (B.C.); (P.M.); (S.N.); (S.T.); (A.Y.); (A.C.); (Z.U.)
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Department of Public Health, Doctoral School of Basic and Translational Medicine, Semmelweis University, 1089 Budapest, Hungary
| | - Peter Mukli
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (R.G.); (B.C.); (P.M.); (S.N.); (S.T.); (A.Y.); (A.C.); (Z.U.)
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Department of Public Health, Doctoral School of Basic and Translational Medicine, Semmelweis University, 1089 Budapest, Hungary
| | - Sharon Negri
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (R.G.); (B.C.); (P.M.); (S.N.); (S.T.); (A.Y.); (A.C.); (Z.U.)
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Stefano Tarantini
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (R.G.); (B.C.); (P.M.); (S.N.); (S.T.); (A.Y.); (A.C.); (Z.U.)
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Department of Public Health, Doctoral School of Basic and Translational Medicine, Semmelweis University, 1089 Budapest, Hungary
- Stephenson Cancer Center, University of Oklahoma, Oklahoma City, OK 73104, USA
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Andriy Yabluchanskiy
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (R.G.); (B.C.); (P.M.); (S.N.); (S.T.); (A.Y.); (A.C.); (Z.U.)
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Department of Public Health, Doctoral School of Basic and Translational Medicine, Semmelweis University, 1089 Budapest, Hungary
- Stephenson Cancer Center, University of Oklahoma, Oklahoma City, OK 73104, USA
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Zoltan Benyo
- Institute of Translational Medicine, Semmelweis University, 1094 Budapest, Hungary;
- Cerebrovascular and Neurocognitive Disorders Research Group, Eötvös Loránd Research Network, Semmelweis University, 1094 Budapest, Hungary
| | - Anna Csiszar
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (R.G.); (B.C.); (P.M.); (S.N.); (S.T.); (A.Y.); (A.C.); (Z.U.)
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Stephenson Cancer Center, University of Oklahoma, Oklahoma City, OK 73104, USA
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Department of Translational Medicine, Doctoral School of Basic and Translational Medicine, Semmelweis University, 1089 Budapest, Hungary
| | - Zoltan Ungvari
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (R.G.); (B.C.); (P.M.); (S.N.); (S.T.); (A.Y.); (A.C.); (Z.U.)
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Department of Public Health, Doctoral School of Basic and Translational Medicine, Semmelweis University, 1089 Budapest, Hungary
- Stephenson Cancer Center, University of Oklahoma, Oklahoma City, OK 73104, USA
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| |
Collapse
|
2
|
M.sofiullah SS, Murugan DD, Muid SA, Wu YS, Zamakshshari NH, Quan FG, Patrick M, Choy KW. Thymoquinone reverses homocysteine-induced endothelial dysfunction via inhibition of ER-stress induced oxidative stress pathway.. [DOI: 10.21203/rs.3.rs-2964177/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
Abstract
Hyperhomocysteinemia has been linked to an increased risk of cardiovascular diseases. High levels of homocysteine (Hcy) promote endoplasmic reticulum (ER) stress that can increase reactive oxygen species (ROS), leading to endothelial dysfunction. Thymoquinone (TQ) is the major active ingredient in Nigella sativa seeds volatile oil and is shown to have a cardioprotective effect. However, no study evaluated the effect of TQ against Hcy-induced endothelial dysfunction. Thus, this study aims to investigate the effects and mechanisms of TQ in reversing Hcy-induced endothelial dysfunction. Isolated aorta from male Sprague-Dawley (SD) rats incubated with Hcy (500 µM) and co-treated with or without TQ (0.1 µM, 1 µM, and 10 µM), 20 µM TUDCA, 100 µM Apocynin or 1 mM Tempol in organ bath to study the vascular function. Additionally, human umbilical vein endothelial cells (HUVECs) were incubated with Hcy (10 mM) and various concentrations of TQ (1 and 10 𝜇M), Tempol (100 𝜇M), Apocynin (100 𝜇M), TUDCA (100 𝜇M) or H2O2 (0.25 mM) to evaluate the cell viability by using a phase contrast microscope and dye exclusion assay. Involvement of ER stress pathway, ROS and NO bioavailability were accessed via immunoassay and fluorescent staining respectively. Molecular docking was performed to evaluate the binding affinity of TQ to GRP78. Our results revealed that Hcy impaired endothelium-dependant relaxation in isolated aorta and induced apoptosis in HUVECs. These effects were reversed by TQ, TUDCA, tempol and apocynin. Treatment with TQ (10𝜇M) also reduced ROS level, improved NO bioavailability as well reduced GRP78 and NOX4 protein in HUVECs. Result from the molecular docking study showed that TQ could bind well to GRP78 through hydrogen bond and hydrophobic interaction with the amino acid at GRP78 ATP binding pocket. Taken together, the present results suggest that TQ preserved endothelial function in rat aorta and reduced apoptosis of HUVECs induced by Hcy through the inhibition of ER stress-mediated ROS and eNOS uncoupling.
Collapse
|
3
|
Stone RM, Ainslie PN, Tremblay JC, Akins JD, MacLeod DB, Tymko MM, DeSouza CA, Bain AR. GLOBAL REACH 2018: intra-arterial vitamin C improves endothelial-dependent vasodilatory function in humans at high altitude. J Physiol 2021; 600:1373-1383. [PMID: 34743333 DOI: 10.1113/jp282281] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/11/2021] [Indexed: 12/20/2022] Open
Abstract
High altitude-induced hypoxaemia is often associated with peripheral vascular dysfunction. However, the basic mechanism(s) underlying high-altitude vascular impairments remains unclear. This study tested the hypothesis that oxidative stress contributes to the impairments in endothelial function during early acclimatization to high altitude. Ten young healthy lowlanders were tested at sea level (344 m) and following 4-6 days at high altitude (4300 m). Vascular endothelial function was determined using the isolated perfused forearm technique with forearm blood flow (FBF) measured by strain-gauge venous occlusion plethysmography. FBF was quantified in response to acetylcholine (ACh), sodium nitroprusside (SNP) and a co-infusion of ACh with the antioxidant vitamin C (ACh+VitC). The total FBF response to ACh (area under the curve) was ∼30% lower at high altitude than at sea level (P = 0.048). There was no difference in the response to SNP at high altitude (P = 0.860). At sea level, the co-infusion of ACh+VitC had no influence on the FBF dose response (P = 0.268); however, at high altitude ACh+VitC resulted in an average increase in the FBF dose response by ∼20% (P = 0.019). At high altitude, the decreased FBF response to ACh, and the increase in FBF in response to ACh+VitC, were associated with the magnitude of arterial hypoxaemia (R2 = 0.60, P = 0.008 and R2 = 0.63, P = 0.006, respectively). Collectively, these data support the hypothesis that impairments in vascular endothelial function at high altitude are in part attributable to oxidative stress, a consequence of the magnitude of hypoxaemia. These data extend our basic understanding of vascular (mal)adaptation to high-altitude sojourns, with important implications for understanding the aetiology of high altitude-related vascular dysfunction. KEY POINTS: Vascular dysfunction has been demonstrated in lowlanders at high altitude (>4000 m). However, the extent of impairment and the delineation of contributing mechanisms have remained unclear. Using the gold-standard isolated perfused forearm model, we determined the extent of vasodilatory dysfunction and oxidative stress as a contributing mechanism in healthy lowlanders before and 4-6 days after rapid ascent to 4300 m. The total forearm blood flow response to acetylcholine at high altitude was decreased by ∼30%. Co-infusion of acetylcholine with the antioxidant vitamin C partially restored the total forearm blood flow by ∼20%. The magnitude of forearm blood flow reduction, as well as the impact of oxidative stress, was positively associated with the individual severity of hypoxaemia. These data extend our basic understanding of vascular (mal)adaptation to high-altitude sojourns, with important implications for understanding the aetiology of high altitude-related changes in endothelial-mediated vasodilatory function.
Collapse
Affiliation(s)
- Rachel M Stone
- Faculty of Human Kinetics, University of Windsor, Ontario, Canada
| | - Philip N Ainslie
- Kelowna, Centre for Heart Lung and Vascular Health, University of British Columbia, Vancouver, Canada
| | - Joshua C Tremblay
- Kelowna, Centre for Heart Lung and Vascular Health, University of British Columbia, Vancouver, Canada
| | | | - David B MacLeod
- Duke University School of Medicine, Durham, North Carolina, USA
| | | | | | - Anthony R Bain
- Faculty of Human Kinetics, University of Windsor, Ontario, Canada
| |
Collapse
|
4
|
Cziráki A, Lenkey Z, Sulyok E, Szokodi I, Koller A. L-Arginine-Nitric Oxide-Asymmetric Dimethylarginine Pathway and the Coronary Circulation: Translation of Basic Science Results to Clinical Practice. Front Pharmacol 2020; 11:569914. [PMID: 33117166 PMCID: PMC7550781 DOI: 10.3389/fphar.2020.569914] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 09/03/2020] [Indexed: 12/16/2022] Open
Abstract
By 1980, it was thought that we already knew most of the major mechanisms regulating vascular tone. However, after the somewhat serendipity discovery that endothelium is involved in mediation of relaxation to acetylcholine, a whole new world opened up and we had to rewrite our concept regarding vascular function and its regulation (not to mention many other fields). The new player was an endothelium derived relaxing factor, which molecular constitution has been identified to be nitric oxide (NO). This review summarizes the major molecular steps concerning how NO is synthetized from L-arginine. Also, the fate of L-arginine is described via the arginase and methylation pathways; both of them are affecting substantially the level and efficacy of NO. In vitro and in vivo effects of L-arginine are summarized and controversial clinical findings are discussed. On the basis of the use of methylated L-arginines, the vasomotor effects of endothelial NO released to agonists and increases in flow/wall shear stress (a major biological stimulus) is summarized. In this review the role of NO in the regulation of coronary vascular resistance, hence blood flow, is delineated and the somewhat questionable clinical use of NO donors is discussed. We made an attempt to summarize the biosynthesis, role, and molecular mechanisms of endogenously produced methylated L-arginine, asymmetric dimethylarginine (ADMA) in modulating vascular resistance, affecting the function of the heart. Additionally, the relationship between ADMA level and various cardiovascular diseases is described, such as atherosclerosis, coronary artery disease (CAD), ischemia/reperfusion injuries, and different types of coronary revascularization. A novel aspect of coronary vasomotor regulation is identified in which the pericardial fluid ADMA and endothelin play putative roles. Finally, some of the open possibilities for future research on L-arginine-NO-ADMA signaling are highlighted.
Collapse
Affiliation(s)
- Attila Cziráki
- Medical School, Heart Institute, University of Pécs, Pécs, Hungary.,Szentágothai Research Centre, University of Pécs, Pécs, Hungary
| | - Zsófia Lenkey
- Medical School, Heart Institute, University of Pécs, Pécs, Hungary
| | - Endre Sulyok
- Institute of Public Health and Health Promotion, University of Pécs, Pécs, Hungary
| | - István Szokodi
- Medical School, Heart Institute, University of Pécs, Pécs, Hungary.,Szentágothai Research Centre, University of Pécs, Pécs, Hungary
| | - Akos Koller
- Department of Morphology and Physiology, Faculty of Health Sciences, Semmelweis University, Budapest, Hungary.,Research Center for Sports Physiology, University of Physical Education, Budapest, Hungary.,Department of Physiology, New York Medical College, Valhalla, NY, United States
| |
Collapse
|
5
|
Hyperhomocysteinemia impairs regional blood flow: involvements of endothelial and neuronal nitric oxide. Pflugers Arch 2016; 468:1517-25. [PMID: 27417104 DOI: 10.1007/s00424-016-1849-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 06/06/2016] [Accepted: 06/08/2016] [Indexed: 12/13/2022]
Abstract
Increasing evidence support the idea that hyperhomocysteinemia (HHcy) is responsible for pathogenesis underlying cerebral, coronary, renal, and other vascular circulatory disorders and for hypertension. Impaired synthesis of nitric oxide (NO) in the endothelium or increased production of asymmetric dimethylarginine and activated oxygen species are involved in the impairment of vasodilator effects of NO. Impaired circulation in the brain derived from reduced synthesis and actions of NO would be an important triggering factor to dementia and Alzheimer's disease. Reduced actions of NO and brain hypoperfusion trigger increased production of amyloid-β that inhibits endothelial function, thus establishing a vicious cycle for impairing brain circulation. HHcy is involved in the genesis of anginal attack and coronary myocardial infarction. HHcy is also involved in renal circulatory diseases. The homocysteine (Hcy)-induced circulatory failure is promoted by methionine and is prevented by increased folic acid and vitamin B6/B12. Eliminating poor life styles, such as smoking and being sedentary; keeping favorable dietary habits; and early treatment maintaining constitutive NOS functions healthy, reducing oxidative stresses would be beneficial in protecting HHcy-induced circulatory failures.
Collapse
|
6
|
Hill-Eubanks DC, Gonzales AL, Sonkusare SK, Nelson MT. Vascular TRP channels: performing under pressure and going with the flow. Physiology (Bethesda) 2015; 29:343-60. [PMID: 25180264 DOI: 10.1152/physiol.00009.2014] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Endothelial cells and smooth muscle cells of resistance arteries mediate opposing responses to mechanical forces acting on the vasculature, promoting dilation in response to flow and constriction in response to pressure, respectively. In this review, we explore the role of TRP channels, particularly endothelial TRPV4 and smooth muscle TRPC6 and TRPM4 channels, in vascular mechanosensing circuits, placing their putative mechanosensitivity in context with other proposed upstream and downstream signaling pathways.
Collapse
Affiliation(s)
| | - Albert L Gonzales
- Department of Pharmacology, University of Vermont, Burlington, Vermont
| | | | - Mark T Nelson
- Department of Pharmacology, University of Vermont, Burlington, Vermont
| |
Collapse
|
7
|
Sipkens JA, Hahn N, van den Brand CS, Meischl C, Cillessen SAGM, Smith DEC, Juffermans LJM, Musters RJP, Roos D, Jakobs C, Blom HJ, Smulders YM, Krijnen PAJ, Stehouwer CDA, Rauwerda JA, van Hinsbergh VWM, Niessen HWM. Homocysteine-induced apoptosis in endothelial cells coincides with nuclear NOX2 and peri-nuclear NOX4 activity. Cell Biochem Biophys 2014; 67:341-52. [PMID: 22038300 PMCID: PMC3825580 DOI: 10.1007/s12013-011-9297-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Apoptosis of endothelial cells related to homocysteine (Hcy) has been reported in several studies. In this study, we evaluated whether reactive oxygen species (ROS)-producing signaling pathways contribute to Hcy-induced apoptosis induction, with specific emphasis on NADPH oxidases. Human umbilical vein endothelial cells were incubated with 0.01–2.5 mM Hcy. We determined the effect of Hcy on caspase-3 activity, annexin V positivity, intracellular NOX1, NOX2, NOX4, and p47phox expression and localization, nuclear nitrotyrosine accumulation, and mitochondrial membrane potential (ΔΨm). Hcy induced caspase-3 activity and apoptosis; this effect was concentration dependent and maximal after 6-h exposure to 2.5 mM Hcy. It was accompanied by a significant increase in ΔΨm. Cysteine was inactive on these parameters excluding a reactive thiol group effect. Hcy induced an increase in cellular NOX2, p47phox, and NOX4, but not that of NOX1. 3D digital imaging microscopy followed by image deconvolution analysis showed nuclear accumulation of NOX2 and p47phox in endothelial cells exposed to Hcy, but not in control cells, which coincided with accumulation of nuclear nitrotyrosine residues. Furthermore, Hcy enhanced peri-nuclear localization of NOX4 coinciding with accumulation of peri-nuclear nitrotyrosine residues, a reflection of local ROS production. p47phox was also increased in the peri-nuclear region. The Hcy-induced increase in caspase-3 activity was prevented by DPI and apocynin, suggesting involvement of NOX activity. The data presented in this article reveal accumulation of nuclear NOX2 and peri-nuclear NOX4 accumulation as potential source of ROS production in Hcy-induced apoptosis in endothelial cells.
Collapse
Affiliation(s)
- Jessica A Sipkens
- Department of Pathology, VU University Medical Centre, Room 0E46, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Narayanan N, Pushpakumar SB, Givvimani S, Kundu S, Metreveli N, James D, Bratcher AP, Tyagi SC. Epigenetic regulation of aortic remodeling in hyperhomocysteinemia. FASEB J 2014; 28:3411-22. [PMID: 24739303 DOI: 10.1096/fj.14-250183] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Hyperhomocysteinemia (HHcy) is prevalent in patients with hypertension and is an independent risk factor for aortic pathologies. HHcy is known to cause an imbalance between matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs), leading to the accumulation of collagen in the aorta and resulting in stiffness and development of hypertension. Although the exact mechanism of extracellular matrix (ECM) remodeling is unclear, emerging evidence implicates epigenetic regulation involving DNA methylation. Our purpose was to investigate whether 5-aza-2'-deoxycytidine (Aza), a DNA methyltransferase (DNMT1) inhibitor, reduces high blood pressure (BP) by regulating aortic ECM remodeling in HHcy. Wild-type and cystathionine β-synthase (CBS)(+/-) HHcy mice were treated with Aza (0.5 mg/kg body weight). In HHcy mice, Aza treatment normalized the plasma homocysteine (Hcy) level and BP. Thoracic and abdominal aorta ultrasound revealed a reduction in the resistive index and wall-to-lumen ratio. Vascular response to phenylephrine, acetylcholine, and sodium nitroprusside improved after Aza in HHcy mice. Histology showed a marked reduction in collagen deposition in the aorta. Aza treatment decreased the expression of DNMT1, MMP9, TIMP1, and S-adenosyl homocysteine hydrolase (SAHH) and upregulated methylene tetrahydrofolate reductase (MTHFR). We conclude that reduction of DNA methylation by Aza in HHcy reduces adverse aortic remodeling to mitigate hypertension.
Collapse
Affiliation(s)
- Nithya Narayanan
- Department of Physiology and Biophysics, University of Louisville School of Medicine, and
| | | | - Srikanth Givvimani
- Department of Physiology and Biophysics, University of Louisville School of Medicine, and
| | - Sourav Kundu
- Department of Physiology and Biophysics, University of Louisville School of Medicine, and
| | - Naira Metreveli
- Department of Physiology and Biophysics, University of Louisville School of Medicine, and
| | - Dexter James
- Department of Exercise Physiology, University of Louisville, Louisville, Kentucky, USA
| | - Adrienne P Bratcher
- Department of Exercise Physiology, University of Louisville, Louisville, Kentucky, USA
| | - Suresh C Tyagi
- Department of Physiology and Biophysics, University of Louisville School of Medicine, and
| |
Collapse
|
9
|
Hamidi Madani A, Asadolahzade A, Mokhtari G, Shahrokhi Damavand R, Farzan A, Esmaeili S. Assessment of the Efficacy of Combination Therapy with Folic Acid and Tadalafil for the Management of Erectile Dysfunction in Men with Type 2 Diabetes Mellitus. J Sex Med 2013; 10:1146-50. [DOI: 10.1111/jsm.12047] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
10
|
Mayo JN, Beard RS, Price TO, Chen CH, Erickson MA, Ercal N, Banks WA, Bearden SE. Nitrative stress in cerebral endothelium is mediated by mGluR5 in hyperhomocysteinemia. J Cereb Blood Flow Metab 2012; 32:825-34. [PMID: 22186670 PMCID: PMC3345916 DOI: 10.1038/jcbfm.2011.185] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hyperhomocysteinemia (HHcy) disrupts nitric oxide (NO) signaling and increases nitrative stress in cerebral microvascular endothelial cells (CMVECs). This is mediated, in part, by protein nitrotyrosinylation (3-nitrotyrosine; 3-NT) though the mechanisms by which extracellular homocysteine (Hcy) generates intracellular 3-NT are unknown. Using a murine model of mild HHcy (cbs(+/-) mouse), we show that 3-NT is significantly elevated in cerebral microvessels with concomitant reductions in serum NO bioavailability as compared with wild-type littermate controls (cbs(+/+)). Directed pharmacology identified a receptor-dependent mechanism for 3-NT formation in CMVECs. Homocysteine increased expression of inducible NO synthase (iNOS) and formation of 3-NT, both of which were blocked by inhibition of metabotropic glutamate receptor-5 (mGluR5) with the specific antagonist 2-methyl-6-(phenylethynyl) pyridine hydrochloride. Activation of mGluR5 is both sufficient and necessary to drive the nitrative stress because direct activation using the mGluR5-specific agonist (RS)-2-chloro-5-hydroxyphenylglycine also increased iNOS expression and 3-NT formation while knockdown of mGluR5 receptor expression by short hairpin RNA (shRNA) blocked their increase in response to Hcy. Nitric oxide derived from iNOS was required for Hcy-mediated formation of 3-NT because the effect was blocked by 1400W. These results provide the first evidence for a receptor-dependent process that explains how plasma Hcy levels control intracellular nitrative stress in cerebral microvascular endothelium.
Collapse
Affiliation(s)
- Jamie N Mayo
- Department of Biological Sciences, Idaho State University, Pocatello, ID 83209, USA
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Stanger O, Wonisch W. Enzymatic and non-enzymatic antioxidative effects of folic acid and its reduced derivates. Subcell Biochem 2012; 56:131-161. [PMID: 22116698 DOI: 10.1007/978-94-007-2199-9_8] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A great part of the population appears to have insufficient folate intake, especially subgroups with higher demand, as determined through more sensitive methods and parameters currently in use. As the role of folate deficiency in congenital defects, e.g. in cardiovascular and neurodegenerative diseases, and in carcinogenesis has become better understood, folate has been recognized as having great potential to prevent these many disorders through folate supplementation or fortification for the general population. Folates are essential cofactors in the transfer and utilization of one-carbon groups in the process of DNA-biosynthesis with implications for genomic repair and stability. Folate acts indirectly to lower homocysteine levels and insures optimal functioning of the methylation cycle. Homocysteine was shown to be an independent risk factor for neurodegenerative and cardiovascular disease, which includes peripheral vascular disease, coronary artery disease, cerebrovascular disease and venous thrombosis. In fact, it was long believed that the beneficial effects of folate on vascular function and disease are related directly to the mechanism of homocysteine-diminution. Recent investigations have, however, demonstrated beneficial effects of folates unrelated to homocysteine-diminution, suggesting independent properties. One such mechanism could be free radical scavenging and antioxidant activity, as it is now recognized that free radicals play an important role in the oxidative stress leading to many diseases. It was found that folic acid and, in particular, its reduced derivates act both directly and indirectly to produce antioxidant effects. Folates interact with the endothelial enzyme NO synthase (eNOS) and, exert effects on the cofactor bioavailability of NO and thus, on peroxynitrite formation. Folate metabolism provides an interesting example of gene-environmental interaction.
Collapse
Affiliation(s)
- Olaf Stanger
- Heart Division, Cardiothoracic Surgery, Royal Brompton and Harefield NHS Foundation, Imperial College of Science, Technology and Medicine, Sydney Street, London, SW3 6NP, UK,
| | | |
Collapse
|
12
|
Feng J, Zhang D, Chen B. Endothelial mechanisms of endothelial dysfunction in patients with obstructive sleep apnea. Sleep Breath 2011; 16:283-94. [PMID: 21479903 DOI: 10.1007/s11325-011-0519-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 03/23/2011] [Accepted: 03/30/2011] [Indexed: 12/12/2022]
Abstract
BACKGROUND Obstructive sleep apnea (OSA) occurs in 2% of middle-aged women and 4% of middle-aged men in the general population and the prevalence is much higher in specific patient groups. Intermittent hypoxia (IH, oxygen desaturation and re-oxygenation) cycle, a major pathophysiologic character of OSA, and the physiological responses this evokes are thought to be responsible for its association with increased cardiovascular morbidity and mortality. Endothelial dysfunction, resulting from IH and as a key early event in atherosclerosis, was demonstrated repeatedly in patients with OSA and in animal models of IH, providing an important mechanistic link between the acute cyclical IH during sleep and the increased prevalence of chronic vascular diseases. CONCLUSIONS From this work, we conclude that IH from OSA may result in endothelial dysfunction, as a potential promoter of atherosclerosis, through nitric oxide unavailability, oxidative stress and inflammation, cell apoptosis, the crosstalk between endothelial cells and circulating inflammatory cells, microparticles, and damage repairing process. Though effective continuous positive airway pressure (CPAP) may specifically improve endothelial function, more controlled larger interventional trials that will include multiple centers and randomized allocation of CPAP therapy are needed to see if such changes are reversible before cause and effect can be implied finally, while further studies on cellular and animal level are also needed to elucidate molecular biologic/pathologic pathways.
Collapse
Affiliation(s)
- Jing Feng
- Respiratory Department of Tianjin Medical University General Hospital, Tianjin, 300052, China
| | | | | |
Collapse
|
13
|
Lemarié CA, Shbat L, Marchesi C, Angulo OJ, Deschênes ME, Blostein MD, Paradis P, Schiffrin EL. Mthfr deficiency induces endothelial progenitor cell senescence via uncoupling of eNOS and downregulation of SIRT1. Am J Physiol Heart Circ Physiol 2010; 300:H745-53. [PMID: 21169404 DOI: 10.1152/ajpheart.00321.2010] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Hyperhomocysteinemia (HHcy) has been shown to induce endothelial dysfunction in part as a result of enhanced oxidative stress. Function and survival of endothelial progenitor cells (EPCs, defined as sca1(+) c-kit(+) flk-1(+) bone marrow-derived cells), which significantly contribute to neovascularization and endothelial regeneration, depend on controlled production of reactive oxygen species (ROS). Mice heterozygous for the gene deletion of methylenetetrahydrofolate reductase (Mthfr(+/-)) have a 1.5- to 2-fold elevation in plasma homocysteine. This mild HHcy significantly reduced the number of circulating EPCs as well as their differentiation. Mthfr deficiency was also associated with increased ROS production and reduced nitric oxide (NO) generation in Mthfr(+/-) EPCs. Treatment of EPCs with sepiapterin, a precursor of tetrahydrobiopterin (BH(4)), a cofactor of endothelial nitric oxide synthase (eNOS), significantly reduced ROS and improved NO production. mRNA and protein expression of eNOS and the relative amount of eNOS dimer compared with monomer were decreased by Mthfr deficiency. Impaired differentiation of EPCs induced by Mthfr deficiency correlated with increased senescence, decreased telomere length, and reduced expression of SIRT1. Addition of sepiapterin maintained cell senescence and SIRT1 expression at levels comparable to the wild type. Taken together, these results demonstrate that Mthfr deficiency impairs EPC formation and increases EPC senescence by eNOS uncoupling and downregulation of SIRT1.
Collapse
Affiliation(s)
- Catherine A Lemarié
- Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Quebec, Canada
| | | | | | | | | | | | | | | |
Collapse
|
14
|
Colleran PN, Li Z, Yang HT, Laughlin MH, Terjung RL. Vasoresponsiveness of collateral vessels in the rat hindlimb: influence of training. J Physiol 2010. [PMID: 20194126 DOI: 10.1113/jphysiol.2009.18624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Exercise training is known to be an effective means of improving functional capacity and quality of life in patients with peripheral arterial insufficiency (PAI). However, the specific training-induced physiological adaptations occurring within collateral vessels remain to be clearly defined. The purpose of this study was to determine the effect of exercise training on vasomotor properties of isolated peripheral collateral arteries. We hypothesized that daily treadmill exercise would improve the poor vasodilatory capacity of collateral arteries isolated from rats exposed to surgical occlusion of the femoral artery. Following femoral artery ligation, animals were either kept sedentary or exercise trained daily for a period of 3 weeks. Hindlimb collateral arteries were then isolated, cannulated and pressurized via hydrostatic reservoirs to an intravascular pressure of either 45 or 120 cmH(2)O. Non-occluded contralateral vessels of the sedentary animals served as normal Control. Vasodilatory responses to acetylcholine (ACh; 1 x 10(9)-1 x 10(5)m) and sodium nitroprusside (SNP; 1 x 10(9)-1 x 10(4)m), constrictor responses to phenylephrine (PE; 1 x 10(9)-1 x 10(4)m), and flow-induced vasodilatation were determined. Endothelium-mediated vasodilatation responses were significantly greater to either ACh (P < 0.02) or intravascular flow (P < 0.001) in collateral arteries of trained rats. Neither blockade of cyclooxygenase with indomethacin (Indo; 5 microm) nor blockade of endothelial nitric oxide synthase with N(G)-nitro-L-arginine methyl ester (L-NAME; 300 microm) eliminated this ACh- or flow-induced vasodilatation. The depressed vasodilatory response to SNP caused by vascular occlusion was reversed with training. These data indicate that exercise training improves endothelium-mediated vasodilatory capacity of hindlimb collateral arteries, apparently by enhanced production of the putative endothelium-derived hyperpolarizing factor(s). If these findings were applicable to patients with PAI, they could contribute to an improved collateral vessel function and enhance exercise tolerance during routine physical activity.
Collapse
Affiliation(s)
- Patrick N Colleran
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | | | | | | | | |
Collapse
|
15
|
Colleran PN, Li Z, Yang HT, Laughlin MH, Terjung RL. Vasoresponsiveness of collateral vessels in the rat hindlimb: influence of training. J Physiol 2010; 588:1293-307. [PMID: 20194126 DOI: 10.1113/jphysiol.2009.186247] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Exercise training is known to be an effective means of improving functional capacity and quality of life in patients with peripheral arterial insufficiency (PAI). However, the specific training-induced physiological adaptations occurring within collateral vessels remain to be clearly defined. The purpose of this study was to determine the effect of exercise training on vasomotor properties of isolated peripheral collateral arteries. We hypothesized that daily treadmill exercise would improve the poor vasodilatory capacity of collateral arteries isolated from rats exposed to surgical occlusion of the femoral artery. Following femoral artery ligation, animals were either kept sedentary or exercise trained daily for a period of 3 weeks. Hindlimb collateral arteries were then isolated, cannulated and pressurized via hydrostatic reservoirs to an intravascular pressure of either 45 or 120 cmH(2)O. Non-occluded contralateral vessels of the sedentary animals served as normal Control. Vasodilatory responses to acetylcholine (ACh; 1 x 10(9)-1 x 10(5)m) and sodium nitroprusside (SNP; 1 x 10(9)-1 x 10(4)m), constrictor responses to phenylephrine (PE; 1 x 10(9)-1 x 10(4)m), and flow-induced vasodilatation were determined. Endothelium-mediated vasodilatation responses were significantly greater to either ACh (P < 0.02) or intravascular flow (P < 0.001) in collateral arteries of trained rats. Neither blockade of cyclooxygenase with indomethacin (Indo; 5 microm) nor blockade of endothelial nitric oxide synthase with N(G)-nitro-L-arginine methyl ester (L-NAME; 300 microm) eliminated this ACh- or flow-induced vasodilatation. The depressed vasodilatory response to SNP caused by vascular occlusion was reversed with training. These data indicate that exercise training improves endothelium-mediated vasodilatory capacity of hindlimb collateral arteries, apparently by enhanced production of the putative endothelium-derived hyperpolarizing factor(s). If these findings were applicable to patients with PAI, they could contribute to an improved collateral vessel function and enhance exercise tolerance during routine physical activity.
Collapse
Affiliation(s)
- Patrick N Colleran
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | | | | | | | | |
Collapse
|
16
|
Racz A, Veresh Z, Lotz G, Bagi Z, Koller A. Cyclooxygenase-2 derived thromboxane A(2) and reactive oxygen species mediate flow-induced constrictions of venules in hyperhomocysteinemia. Atherosclerosis 2009; 208:43-9. [PMID: 19615686 DOI: 10.1016/j.atherosclerosis.2009.06.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 06/02/2009] [Accepted: 06/08/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVE Hyperhomocysteinemia (HHcy) has been shown to impair the endothelial function of arterial vessels and promote thrombosis. There are no studies, however, assessing the effects of HHcy on the vasomotor function of venules. We hypothesized that HHcy activates pathophysiological mechanisms impairing flow/shear stress-dependent responses of venules. METHODS AND RESULTS Changes in diameter of isolated gracilis muscle venules (diameter: approximately 250 microm at 10 mmHg) of control and HHcy rats (induced by methionine diet for 5 weeks) to increases in intraluminal flow were measured. Increases in flow elicited dilations in control (at max.: 14+/-1%), but induced constrictions in HHcy venules (at max.: -24+/-4%). Flow-induced constrictions in HHcy venules were converted to dilations in the presence of the thromboxane A(2) (TxA(2)) receptor (TP) antagonist SQ 29,548, which were then abolished by the simultaneous administration of nitric oxide (NO) synthase inhibitor, L-NAME and non-selective cyclooxygenase (COX) blocker, indomethacin. In addition, the selective COX-2 inhibitor NS 398 reversed flow-induced constrictions to dilations, which were significantly decreased by additional COX-1 inhibitor, SC 560. Also, as compared to controls, a SOD/CAT sensitive increased ethidium bromide fluorescence was detected in HHcy small veins, indicating substantial production of reactive oxygen species (ROS) in HHcy. Correspondingly, SOD/CAT diminished flow-induced constrictions in venules of HHcy rats. CONCLUSIONS In hyperhomocysteinemia increases in flow/shear stress increases the production of COX-2-derived TxA(2), and reactive oxygen species--that overcome the dilator effects of NO and prostaglandins--eliciting constrictions in skeletal muscle venules; changes which can increase vascular resistance and favor thrombus formation in the venular circulation.
Collapse
Affiliation(s)
- Anita Racz
- Department of Pathophysiology, Semmelweis University, Budapest, Hungary
| | | | | | | | | |
Collapse
|
17
|
Bea F, Hudson FN, Neff-Laford H, White CC, Kavanagh TJ, Kreuzer J, Preusch MR, Blessing E, Katus HA, Rosenfeld ME. Homocysteine stimulates antioxidant response element-mediated expression of glutamate-cysteine ligase in mouse macrophages. Atherosclerosis 2009; 203:105-11. [PMID: 18691715 PMCID: PMC3770138 DOI: 10.1016/j.atherosclerosis.2008.06.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Revised: 06/06/2008] [Accepted: 06/19/2008] [Indexed: 11/30/2022]
Abstract
Hyperhomocysteinemia is an independent risk factor for atherosclerosis. Uptake of homocysteine induces oxidative stress in macrophages. Antioxidant response elements (AREs) are regulatory elements within promoters of genes, which protect cells against oxidative stress. The current study investigated whether homocysteine induces transcription of glutamate-cysteine ligase (Gcl), via ARE driven gene expression in mouse macrophages. Gcl is the rate-limiting enzyme in the synthesis of glutathione, an important endogenous antioxidant. Gcl is heterodimeric and the genes encoding the subunits of Gcl contain several AREs within their 5'-promoter regions. Treatment of mouse macrophages with d-/l-homocysteine (50microM) induced depletion of intracellular glutathione and a compensatory increase in Gcl activity. Electro mobiliy shift assays demonstrated increased binding of nuclear proteins to ARE-containing oligonucleotides. Real-time RT-PCR revealed increased mRNA-expression of the catalytic subunit of Gcl (Gclc) after treatment with homocysteine, and this occurred via increased transcription as demonstrated with luciferase promoter reporter constructs for Gclc. Additional site directed mutagenesis demonstrated that ARE4 plays a direct role in mediating induction of Gclc by homocysteine. Supershift analysis and Western blotting revealed that Nrf2 signalling is critical in homocysteine-induced activation of ARE4. Inhibition of MAP kinase activity reduced binding of nuclear proteins to the AREs, nuclear expression of Nrf2 and mRNA expression of Gclc. Western blotting demonstrated phosporylation of ERK1/2 in homocysteine treated macrophages. These data suggest that ARE-driven gene expression of Gclc via a MEK/Nrf2 pathway could help to protect macrophages from oxidative stress due to hyperhomocysteinemia.
Collapse
Affiliation(s)
- Florian Bea
- Department of Internal Medicine III, University of Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Yu X, Cheng X, Xie JJ, Liao MY, Yao R, Chen Y, Ding YJ, Tang TT, Liao YH. Poly (ADP-ribose) polymerase inhibition improves endothelial dysfunction induced by hyperhomocysteinemia in rats. Cardiovasc Drugs Ther 2008; 23:121-7. [PMID: 18949543 DOI: 10.1007/s10557-008-6146-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Accepted: 10/02/2008] [Indexed: 01/06/2023]
Abstract
INTRODUCTION We investigated the possible protective effect of poly (ADP-ribose) polymerase (PARP) inhibition in preventing endothelial dysfunction induced by hyperhomocysteinemia (Hhcy). METHODS Sprague-Dawley rats were divided into Hhcy group, Hhcy + 3-aminobenzamide(3-AB) group, control group and control + 3-AB group. A high-methionine diet was given to induce hyperhomocysteinemia. In Hhcy + 3-AB and control + 3-AB groups, rats were injected intraperitoneally with 3-AB (inhibitor of PARP). After 45 days, ultrastructural changes of aortas were observed by transmission electron microscope. Vascular reactivity of thoracic aortic rings was measured in organ chambers. PARP activity was detected. The levels of plasma total homocysteine, nitrite/nitrate, endothelin (ET)-1 and malondialdehyde were assayed. RESULTS Rats in Hhcy group developed severe hyperhomocysteinemia and significant loss of endothelial function as measured by both vascular rings and levels of nitrite/nitrate and ET-1. Malondialdehyde levels increased significantly in Hhcy rats compared with control rats. 3-AB improved Ach-induced, NO-mediated vascular relaxation and stabilized the level of nitrite/nitrate and ET-1. Obvious improvement of ultrastructure can be observed in Hhcy + 3-AB group. CONCLUSIONS These results suggest that pharmacological inhibition of PARP prevents the development of endothelial dysfunction in rats with hyperhomocysteinemia which may represent a novel approach to improve vascular dysfunction associated with hyperhomocysteinemia.
Collapse
Affiliation(s)
- Xian Yu
- Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Khayat R, Patt B, Hayes D. Obstructive sleep apnea: the new cardiovascular disease. Part I: Obstructive sleep apnea and the pathogenesis of vascular disease. Heart Fail Rev 2008; 14:143-53. [PMID: 18807180 DOI: 10.1007/s10741-008-9112-z] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Accepted: 08/12/2008] [Indexed: 12/21/2022]
Abstract
Obstructive sleep apnea (OSA) is increasingly recognized as a novel cardiovascular risk factor. OSA is implicated in the pathogenesis of hypertension, left ventricular dysfunction, coronary artery disease and stroke. OSA exerts its negative cardiovascular consequences through its unique pattern of intermittent hypoxia. Endothelial dysfunction, oxidative stress, and inflammation are all consequences of OSA directly linked to intermittent hypoxia and critical pathways in the pathogenesis of cardiovascular disease in patients with OSA. This review will discuss the known mechanisms of vascular dysfunction in patients with OSA and their implications for cardiovascular disease.
Collapse
Affiliation(s)
- Rami Khayat
- The Ohio State University Sleep Heart Program, The Ohio State University, 473 W 12th Ave, Suite 105, Columbus, OH 43210, USA
| | | | | |
Collapse
|
20
|
Csiszar A, Wang M, Lakatta EG, Ungvari Z. Inflammation and endothelial dysfunction during aging: role of NF-kappaB. J Appl Physiol (1985) 2008; 105:1333-41. [PMID: 18599677 DOI: 10.1152/japplphysiol.90470.2008] [Citation(s) in RCA: 327] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
One of the major conceptual advances in our understanding of the pathogenesis of age-associated cardiovascular diseases has been the insight that age-related oxidative stress may promote vascular inflammation even in the absence of traditional risk factors associated with atherogenesis (e.g., hypertension or metabolic diseases). In the present review we summarize recent experimental data suggesting that mitochondrial production of reactive oxygen species, innate immunity, the local TNF-alpha-converting enzyme (TACE)-TNF-alpha, and the renin-angiotensin system may underlie NF-kappaB induction and endothelial activation in aged arteries. The theme that emerges from this review is that multiple proinflammatory pathways converge on NF-kappaB in the aged arterial wall, and that the transcriptional activity of NF-kappaB is regulated by multiple nuclear factors during aging, including nuclear enzymes poly(ADP-ribose) polymerase (PARP-1) and SIRT-1. We also discuss the possibility that nucleophosmin (NPM or nuclear phosphoprotein B23), a known modulator of the cellular oxidative stress response, may also regulate NF-kappaB activity in endothelial cells.
Collapse
Affiliation(s)
- Anna Csiszar
- Department of Physiology, New York Medical College, Valhalla, NY 10595, USA.
| | | | | | | |
Collapse
|
21
|
Stapleton PA, James ME, Goodwill AG, Frisbee JC. Obesity and vascular dysfunction. ACTA ACUST UNITED AC 2008; 15:79-89. [PMID: 18571908 DOI: 10.1016/j.pathophys.2008.04.007] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Revised: 02/18/2008] [Accepted: 04/28/2008] [Indexed: 01/04/2023]
Abstract
One of the most profound challenges facing public health and public health policy in Western society is the increased incidence and prevalence of both overweight and obesity. While this condition can have significant consequences for patient mortality and quality of life, it can be further exacerbated as overweight/obesity can be a powerful stimulus for the development of additional risk factors for a negative cardiovascular outcome, including increased insulin resistance, dyslipidemia and hypertension. This manuscript will present the effects of systemic obesity on broad issues of vascular function in both afflicted human populations and in the most relevant animal models. Among the topics that will be covered are alterations to vascular reactivity (both dilator and constrictor responses), adaptations in microvascular network and vessel wall structure, and alterations to the patterns of tissue/organ perfusion as a result of the progression of the obese condition. Additionally, special attention will be paid to the contribution of chronic inflammation as a contributor to alterations in vascular function, as well as the role of perivascular adipose tissue in terms of impacting vessel behavior. When taken together, it is clearly apparent that the development of the obese condition can have profound, and frequently difficult to predict, impacts on integrated vascular function. Much of this complexity appears to have its basis in the extent to which other co-morbidities associated with obesity (e.g., insulin resistance) are present and exert contributing effects.
Collapse
Affiliation(s)
- Phoebe A Stapleton
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV 26506, USA
| | | | | | | |
Collapse
|
22
|
Moshal KS, Zeldin DC, Sithu SD, Sen U, Tyagi N, Kumar M, Hughes WM, Metreveli N, Rosenberger DSE, Singh M, Vacek TP, Rodriguez WE, Ayotunde A, Tyagi SC. Cytochrome P450 (CYP) 2J2 gene transfection attenuates MMP-9 via inhibition of NF-kappabeta in hyperhomocysteinemia. J Cell Physiol 2008; 215:771-81. [PMID: 18181170 DOI: 10.1002/jcp.21356] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Hyperhomocysteinemia (HHcy) is associated with atherosclerotic events involving the modulation of arachidonic acid (AA) metabolism and the activation of matrix metalloproteinase-9 (MMP-9). Cytochrome P450 (CYP) epoxygenase-2J2 (CYP2J2) is abundant in the heart endothelium, and its AA metabolites epoxyeicosatrienoic acids (EETs) mitigates inflammation through NF-kappabeta. However, the underlying molecular mechanisms for MMP-9 regulation by CYP2J2 in HHcy remain obscure. We sought to determine the molecular mechanisms by which P450 epoxygenase gene transfection or EETs supplementation attenuate homocysteine (Hcy)-induced MMP-9 activation. CYP2J2 was over-expressed in mouse aortic endothelial cells (MAECs) by transfection with the pcDNA3.1/CYP2J2 vector. The effects of P450 epoxygenase transfection or exogenous supplementation of EETs on NF-kappabeta-mediated MMP-9 regulation were evaluated using Western blot, in-gel gelatin zymography, electromobility shift assay, immunocytochemistry. The result suggested that Hcy downregulated CYP2J2 protein expression and dephosphorylated PI3K-dependent AKT signal. Hcy induced the nuclear translocation of NF-kappabeta via downregulation of IKbetaalpha (endogenous cytoplasmic inhibitor of NF-kappabeta). Hcy induced MMP-9 activation by increasing NF-kappabeta-DNA binding. Moreover, P450 epoxygenase transfection or exogenous addition of 8,9-EET phosphorylated the AKT and attenuated Hcy-induced MMP-9 activation. This occurred, in part, by the inhibition of NF-kappabeta nuclear translocation, NF-kappabeta-DNA binding and activation of IKbetaalpha. The study unequivocally suggested the pivotal role of EETs in the modulation of Hcy/MMP-9 signal.
Collapse
Affiliation(s)
- Karni S Moshal
- Department of Physiology and Biophysics, School of Medicine University of Louisville, Louisville, Kentucky 40202, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Abstract
Hyperhomocysteinemia is a risk factor for cardiovascular disease, stroke, and thrombosis. Several animal models of hyperhomocysteinemia have been developed by using both dietary and genetic approaches. These animal models have provided considerable insight into the mechanisms underlying the adverse vascular effects of hyperhomocysteinemia. Accumulating evidence suggests a significant role of altered cellular redox reactions in the vascular phenotype of hyperhomocysteinemia. Redox effects of hyperhomocysteinemia are particularly important in mediating the adverse effects of hyperhomocysteinemia on the endothelium, leading to loss of endothelium-derived nitric oxide and vasomotor dysfunction. Redox reactions also may be key factors in the development of vascular hypertrophy, thrombosis, and atherosclerosis in hyperhomocysteinemic animals. In this review, we summarize the metabolic relations between homocysteine and the cellular redox state, the vascular phenotypes that have been observed in hyperhomocysteinemic animals, the evidence for altered redox reactions in vascular tissue, and the specific redox reactions that may mediate the vascular effects of hyperhomocysteinemia.
Collapse
Affiliation(s)
- Sanjana Dayal
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | | |
Collapse
|
24
|
Carnicer R, Navarro MA, Arbonés-Mainar JM, Arnal C, Surra JC, Acín S, Sarría A, Blanco-Vaca F, Maeda N, Osada J. Genetically based hypertension generated through interaction of mild hypoalphalipoproteinemia and mild hyperhomocysteinemia. J Hypertens 2007; 25:1597-607. [PMID: 17620955 DOI: 10.1097/hjh.0b013e3281ab6c3d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Hyperhomocysteinemia and hypoalphalipoproteinemia are two well-reported risk factors for cardiovascular disease. The effects of the synergistic combination of these two factors on vascular function need to be investigated. METHODS AND RESULTS Four groups of male mice were used: a control wild-type group; a group of mice heterozygous for cystathionine beta-synthase deficiency; a group of mice heterozygous for apolipoprotein A-I deficiency; and, finally, a group of double heterozygous mice, with both cystathionine beta-synthase and apolipoprotein A-I deficiency. To characterize the resulting phenotype, several parameters including plasma apolipoproteins, lipid profiles, homocysteine, blood pressure and aortic protein were analyzed. As expected, our results indicate that double heterozygous mice are a model of mild hypoalphalipoproteinemia and hyperhomocysteinemia. Further, the additive combination of both risk factors resulted in a significant increase in blood pressure compared with control animals (136 +/- 8.0 versus 126 +/- 7.5 mm Hg, P < 0.01) that was not present in single heterozygous mice. The increase in blood pressure was associated with decreased plasma nitric oxide levels, left ventricle hypertrophy and was independent of low-density lipoprotein (LDL) cholesterol, para-oxonase activity and kidney histological changes. Concomitant decreases in levels of apolipoprotein A-IV (APOA-IV) and caveolin-1 content were also found in the double heterozygous group. CONCLUSIONS Our findings suggest an additive adverse effect of hypoalphalipoproteinemia and hyperhomocysteinemia on endothelial function to generate clinical hypertension and cardiac muscle hypertrophy mediated by dysregulation in nitric oxide metabolism.
Collapse
Affiliation(s)
- Ricardo Carnicer
- Departamento de Bioquímica y Biología Molecular y Celular, Barcelona, Spain
| | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Toth E, Racz A, Toth J, Kaminski PM, Wolin MS, Bagi Z, Koller A. Contribution of polyol pathway to arteriolar dysfunction in hyperglycemia. Role of oxidative stress, reduced NO, and enhanced PGH(2)/TXA(2) mediation. Am J Physiol Heart Circ Physiol 2007; 293:H3096-104. [PMID: 17873009 DOI: 10.1152/ajpheart.01335.2006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hyperglycemia increases glucose metabolism via the polyol pathway, which results in elevations of intracellular sorbitol concentration. Thus we hypothesized that elevated level of sorbitol contributes to the development of hyperglycemia-induced dysfunction of microvessels. In isolated, pressurized (80 mmHg) rat gracilis muscle arterioles (approximately 150 microm), high glucose treatment (25 mM) induced reduction in flow-dependent dilation (from maximum of 39 +/- 2% to 15 +/- 1%), which was significantly mitigated by an aldose reductase inhibitor, zopolrestat (maximum 27 +/- 2%). Increasing doses of sorbitol (10(-10)-10(-4) M) elicited dose-dependent constrictions (maximum 22 +/- 3%), which were abolished by endothelium removal, a prostaglandin H(2)/thromboxane A(2) (PGH(2)/TXA(2)) receptor (TP) antagonist SQ-29548, or superoxide dismutase (SOD) plus catalase (CAT). Incubation of arterioles with sorbitol (10(-7) M) reduced flow-dependent dilations (from maximum of 39 +/- 2% to 20 +/- 1.5%), which was not further affected by inhibition of nitric oxide synthase by N(omega)-nitro-l-arginine methyl ester but was prevented by SOD plus CAT and mitigated by SQ-29548. Nitric oxide donor sodium nitroprusside-induced (10(-9)-10(-6) M) dilations were also decreased in a SQ-29548 and SOD plus CAT-reversible manner, whereas adenosine dilations were not affected by sorbitol exposure. Sorbitol significantly increased arterial superoxide production detected by lucigenin-enhanced chemiluminescence, which was inhibited by SOD plus CAT. Sorbitol treatment also increased arterial formation of 3-nitrotyrosine. We suggest that hyperglycemia by elevating intracellular sorbitol induces oxidative stress, which interferes with nitric oxide bioavailability and promotes PGH(2)/TXA(2) release, both of which affect regulation of vasomotor responses of arterioles. Thus increased activity of the polyol pathway may contribute to the development of microvascular dysfunction in diabetes mellitus.
Collapse
Affiliation(s)
- Erika Toth
- Department of Physiology, Semmelweis University, Budapest, Hungary
| | | | | | | | | | | | | |
Collapse
|
26
|
Liu YH, You Y, Song T, Wu SJ, Liu LY. Impairment of Endothelium-Dependent Relaxation of Rat Aortas by Homocysteine Thiolactone and Attenuation by Captopril. J Cardiovasc Pharmacol 2007; 50:155-61. [PMID: 17703131 DOI: 10.1097/fjc.0b013e31805c9410] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
To explore the effects of angiotensin-converting enzyme (ACE) inhibitors on endothelial dysfunction induced by homocysteine thiolactone (HTL). Both endothelium-dependent relaxation and nondependent relaxation of thoracic aortic rings in rats induced by acetylcholine (Ach) or sodium nitroprusside (SNP) and biochemical parameters including malondialdehyde (MDA) and nitric oxide (NO) were measured in rat isolated aorta. Exposure of aortic rings to HTL (3 to 30 mM) for 90 minutes made a significant inhibition of endothelium-dependent relaxation induced by Ach, decreased contents of NO, and increased MDA concentration in aortic tissue. After incubation of aortic rings with captopril (0.003 to 0.03 mM) attenuated the inhibition of endothelium-dependent relaxation (EDR) and significantly resisted the decrease of NO content and elevation of MDA concentration caused by HTL (30 mmol/L) in aortic tissues, a similarly protective effect was observed when the aortic rings were incubated with both N-acetylcysteine (0.05 mM). Treatment with enalaprilat (0.003 to 0.01 mM) made no significant difference with the HTL (30 mM) group regarding EDR, but enalaprilat (0.03 mM) and losartan (0.03 mM) could partly restore the EDR in response to HTL (30 mM). Captopril was more effective than enalaprilat and losartan in attenuation of the inhibition of on acetylcholine-stimulated aortic relaxation by HTL in the same concentration. Moreover, superoxide dismutase (SOD, 200 U/mL), which is a scavenger of superoxide anions, apocynin (0.03 mM), which is an inhibitor of NADPH oxidase, and l-Arginine (3 mmol/L), a precursor of nitric oxide (NO), could reduce HTL (30 mM)-induced inhibition of EDR. After pretreatment with not only the NO synthase inhibitor Nomega-nitro-l-arginine methyl ester (L-NAME, 0.01 mM) but also the free sulfhydryl group blocking agent p-hydroxymercurybenzoate (PHMB, 0.05 mM) could abolish the protection of captopril and N-acetylcysteine, respectively. These results suggest that mechanisms of endothelial dysfunction induced by HTL may include the decrease of NO and the generation of oxygen free radicals and that captopril can restore the inhibition of EDR induced by HTL in isolated rat aorta, which may be related to scavenging oxygen free radicals and may be sulfhydryl-dependent.
Collapse
Affiliation(s)
- Yu-Hui Liu
- Department of Pharmacology, Pharmaceutical College, Central South University, Changsha, Hunan, PR China.
| | | | | | | | | |
Collapse
|
27
|
Focardi M, Dick GM, Picchi A, Zhang C, Chilian WM. Restoration of coronary endothelial function in obese Zucker rats by a low-carbohydrate diet. Am J Physiol Heart Circ Physiol 2007; 292:H2093-9. [PMID: 17220180 DOI: 10.1152/ajpheart.01202.2006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A popular diet used for weight reduction is the low-carbohydrate diet, which has most calories derived from fat and protein, but effects of this dietary regimen on coronary vascular function have not been identified. We tested the hypothesis that obesity-induced impairment in coronary endothelial function is reversed by a low-carbohydrate diet. We used four groups of male Zucker rats: lean and obese on normal and low-carbohydrate diets. Rats were fed ad libitum for 3 wk; total caloric intake and weight gain were similar in both diets. To assess endothelial and vascular function, coronary arterioles were cannulated and pressurized for diameter measurements during administration of acetylcholine or sodium nitroprusside or during flow. When compared with lean rats, endothelium-dependent acetylcholine-induced vasodilation was impaired by approximately 50% in obese rats (normal diet), but it was restored to normal by the low-carbohydrate diet. When the normal diet was fed, flow-induced dilation (FID) was impaired by >50% in obese compared with lean rats. Similar to acetylcholine, responses to FID were restored to normal by a low-carbohydrate diet. N(omega)-nitro-L-arginine methyl ester (10 microM), an inhibitor of nitric oxide (NO) synthase, inhibited acetylcholine- and flow-induced dilation in lean rats, but it had no effect on acetylcholine- or flow-induced vasodilation in obese rats on a low-carbohydrate diet. Tetraethylammonium, a nonspecific K(+) channel antagonist, blocked flow-dependent dilation in the obese rats, suggesting that the improvement in function was mediated by a hyperpolarizing factor independent of NO. In conclusion, obesity-induced impairment in endothelium-dependent vasodilation of coronary arterioles can be dramatically improved with a low-carbohydrate diet most likely through the production of a hyperpolarizing factor independent of NO.
Collapse
Affiliation(s)
- Marta Focardi
- Department of Physiology, Louisiana State University Health Sciences Center, 1901 Perdido Street, New Orleans, LA 70112, USA
| | | | | | | | | |
Collapse
|
28
|
Orosz Z, Csiszar A, Labinskyy N, Smith K, Kaminski PM, Ferdinandy P, Wolin MS, Rivera A, Ungvari Z. Cigarette smoke-induced proinflammatory alterations in the endothelial phenotype: role of NAD(P)H oxidase activation. Am J Physiol Heart Circ Physiol 2007; 292:H130-9. [PMID: 17213480 DOI: 10.1152/ajpheart.00599.2006] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although the cardiovascular morbidity and mortality induced by cigarette smoking exceed those attributable to lung cancer, the molecular basis of smoking-induced vascular injury remains unclear. To test the link between cigarette smoke, oxidative stress, and vascular inflammation, rats were exposed to the smoke of five cigarettes per day (for 1 wk). Also, isolated arteries were exposed to cigarette smoke extract (CSE; 0 to 40 μg/ml, for 6 h) in organoid culture. We found that smoking impaired acetylcholine-induced relaxations of carotid arteries, which could be improved by the NAD(P)H oxidase inhibitor apocynin. Lucigenin chemiluminescence measurements showed that both smoking and in vitro CSE exposure significantly increased vascular O2•− production. Dihydroethidine staining showed that increased O2•− generation was present both in endothelial and smooth muscle cells. CSE also increased vascular H2O2 production (dichlorofluorescein fluorescence). Vascular mRNA expression of the proinflammatory cytokines IL-1β, IL-6, and TNF-α and that of inducible nitric oxide synthase was significantly increased by both smoking and CSE exposure, which could be prevented by inhibition of NAD(P)H oxidase (diphenyleneiodonium and apocynin) or scavenging of H2O2. In cultured endothelial cells, CSE elicited NF-κB activation and increased monocyte adhesiveness, which were prevented by apocynin and catalase. Thus we propose that water-soluble components of cigarette smoke (which are likely to be present in the bloodstream in vivo in smokers) activate the vascular NAD(P)H oxidase. NAD(P)H oxidase-derived H2O2 activates NF-κB, leading to proinflammatory alterations in vascular phenotype, which likely promotes development of atherosclerosis, especially if other risk factors are also present.
Collapse
Affiliation(s)
- Zsuzsanna Orosz
- Dept. of Physiology, New York Medical College, Valhalla, NY 10595, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Abstract
The discovery that mammalian cells have the ability to synthesize the free radical nitric oxide (NO) has stimulated an extraordinary impetus for scientific research in all the fields of biology and medicine. Since its early description as an endothelial-derived relaxing factor, NO has emerged as a fundamental signaling device regulating virtually every critical cellular function, as well as a potent mediator of cellular damage in a wide range of conditions. Recent evidence indicates that most of the cytotoxicity attributed to NO is rather due to peroxynitrite, produced from the diffusion-controlled reaction between NO and another free radical, the superoxide anion. Peroxynitrite interacts with lipids, DNA, and proteins via direct oxidative reactions or via indirect, radical-mediated mechanisms. These reactions trigger cellular responses ranging from subtle modulations of cell signaling to overwhelming oxidative injury, committing cells to necrosis or apoptosis. In vivo, peroxynitrite generation represents a crucial pathogenic mechanism in conditions such as stroke, myocardial infarction, chronic heart failure, diabetes, circulatory shock, chronic inflammatory diseases, cancer, and neurodegenerative disorders. Hence, novel pharmacological strategies aimed at removing peroxynitrite might represent powerful therapeutic tools in the future. Evidence supporting these novel roles of NO and peroxynitrite is presented in detail in this review.
Collapse
Affiliation(s)
- Pál Pacher
- Section on Oxidative Stress Tissue Injury, Laboratory of Physiologic Studies, National Institutes of Health, National Institute of Alcohol Abuse and Alcoholism, Bethesda, Maryland, USA.
| | | | | |
Collapse
|
30
|
Demir T, Comlekçi A, Demir O, Gülcü A, Calýpkan S, Argun L, Seçil M, Yepil S, Esen A. Hyperhomocysteinemia: a novel risk factor for erectile dysfunction. Metabolism 2006; 55:1564-8. [PMID: 17142125 DOI: 10.1016/j.metabol.2006.03.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2005] [Accepted: 03/27/2006] [Indexed: 10/23/2022]
Abstract
Nitric oxide (NO), the key mediator synthesized by different NO synthase isoenzymes, plays an important role in endothelial function. It was recently shown that hyperhomocysteinemia is an important regulator of NO synthase. We investigated the role of homocysteine (Hcys) in erectile dysfunction (ED), which is associated with the defect in NO generation. Thirty-one nondiabetic patients and 33 control cases were evaluated. Patients with diabetes, coronary artery disease, vitamin B(12), or folate deficiency were excluded in the study. The International Index of Erectile Function questionnaire was used to gauge identified erectile quality. Fasting plasma glucose, total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, vitamin B(12), folic acid, and Hcys levels of patients were measured. Penile color Dupplex ultrasound was used to detect vascular abnormalities in nondiabetic patients with ED. Patients with ED were older than the control subjects (55.6 +/- 8.4 vs 44.5 +/- 4.7 years, respectively; P < .001). Patients with ED had higher fasting plasma glucose, total cholesterol, low-density lipoprotein cholesterol, and Hcys levels. There was a significant negative correlation between mean Hcys level and mean International Index of Erectile Function domain score (P < .001). The penile color Doppler ultrasound findings showed that there was a negative significant correlation between mean Hcys level and the 1st, 5th, and 10th minute's peak-systolic velocity. Logistic regression analysis revealed that age and Hcys levels were the main determinants in ED. Hyperhomocysteinemia, known to be an important risk factor in endothelial dysfunction, seems to be an important determinant in ED. These data suggest that slightly elevated Hcys levels are significantly related with arterial and probably endothelial dysfunction in patients with ED.
Collapse
Affiliation(s)
- Tevfik Demir
- Dokuz Eylul University, School of Medicine, Department of Endocrinology and Metabolism, Izmir, Turkey
| | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Zhang BQ, Hu SJ, Qiu LH, Zhu JH, Xie XJ, Sun J, Zhu ZH, Xia Q, Bian K. Effects of Astragalus membranaceus and its main components on the acute phase endothelial dysfunction induced by homocysteine. Vascul Pharmacol 2006; 46:278-85. [PMID: 17196887 DOI: 10.1016/j.vph.2006.11.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2006] [Revised: 10/14/2006] [Accepted: 11/02/2006] [Indexed: 11/18/2022]
Abstract
OBJECTIVE This study was designed to investigate the effects of Astragalus membranaceus (AM) and its main components, astragalus saponin (ASP), astragalus polysaccharide (APS) and aminobutyric acid (GABA), on homocysteine (Hcy) induced acute impairment of vascular tone and to explore whether the antioxidant mechanism was involved in AM protective effect. METHODS Inhibitory effects of Hcy and protective effects of AM and its main components on endothelium-dependent relaxation of aortic rings were determined by isometric tension recordings and nitric oxide signaling was assayed with 125I-cGMP RIA Kit. Furthermore, generation of reactive oxygen species (ROS) in endothelial cells was detected using 5-(6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (CM-H2DCF-DA). RESULTS Hcy significantly inhibited endothelium-dependent relaxation to acetylcholine (ACh) in a dose-dependent manner, and decreased cGMP levels increased by ACh in aorta. Furthermore, superoxide dismutase (SOD), AM, and ASP markedly attenuated inhibition of vasorelaxation and downregulation of cGMP level by Hcy, and APS exerted a tendency to reverse both of the depressive responses, while GABA had no similar effects. Additionally, partially impaired relaxation by Hcy was completely blocked due to the presence of N(omega)-nitro-L-arginine-methyl ester (L-NAME), which could not be further altered by treatment with AM, ASP, APS or GABA. Finally, Hcy significantly increased intracellular ROS levels in endothelial cells as measured by CM-H2DCF-DA fluorescence. SOD, AM, ASP, and APS, but not GABA, inhibited Hcy-stimulated ROS generation. CONCLUSION This study demonstrated that AM and ASP, potently protected endothelium-dependent relaxation against the acute injury from Hcy through nitric oxide regulatory pathways, in which antioxidation played a key role.
Collapse
Affiliation(s)
- Bi-Qi Zhang
- Department of Cardiology, The First Affiliated Hospital, College of Medicine, Zhejiang University, No. 79, Qingchun St, Hangzhou 310003, Zhejiang, PR China
| | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Mullick AE, Zaid UB, Athanassious CN, Lentz SR, Rutledge JC, Symons JD. Hyperhomocysteinemia increases arterial permeability and stiffness in mice. Am J Physiol Regul Integr Comp Physiol 2006; 291:R1349-54. [PMID: 16793933 DOI: 10.1152/ajpregu.00335.2006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have reported that hyperhomocysteinemia (HHcy) evoked by folate depletion increases arterial permeability and stiffness in rats and that low folate without HHcy increases arterial permeability in mice. In this study, we hypothesized that HHcy independently increases arterial permeability and stiffness in mice. C57BL/6J mice that received rodent chow and water [control (Con), n = 12] or water supplemented with 0.5% l-methionine (HHcy, n = 12) for 18 ± 3 wk had plasma homocysteine concentrations of 8 ± 1 and 41 ± 1 μM, respectively ( P < 0.05), and similar liver folate (∼12 ± 2 μg folate/g liver). Carotid arterial permeability, assessed as dextran accumulation using quantitative fluorescence microscopy, was greater in HHcy (3.95 ± 0.4 ng·min−1·cm−2) versus Con (2.87 ± 0.41 ng·min−1·cm−2) mice ( P < 0.05). Stress versus strain curves generated using an elastigraph indicated that 1) maximal stress (N/mm2), 2) physiological stiffness (low-strain Young's modulus, mN/mm), and 3) maximal stiffness (high-strain Young's modulus, N/mm) were higher ( P < 0.05) in aortas from HHcy versus Con mice. Thus, chronic HHcy increases arterial permeability and stiffness. Carotid arterial permeability also was assessed in age-matched C57BL/6J mice before and after incubation with 1) xanthine (0.4 mg/ml)/xanthine oxidase (0.2 mg/ml; X/XO) to generate superoxide anion (O2−) or 50 μM dl-homocysteine in the presence of 2) vehicle, 3) 300 μM diethylamine-NONOate (DEANO; a nitric oxide donor), or 4) 10−3M 4,5-dihydroxy-1,3-benzene disulfonic acid (tiron; a nonenzymatic intracellular O2−scavenger). Compared with preincubation values, X/XO and dl-homocysteine increased ( P < 0.05) permeability by 66 ± 11% and 123 ± 8%, respectively. dl-Homocysteine-induced increases in dextran accumulation were blunted ( P < 0.05) by simultaneous incubation with DEANO or tiron. Thus, acute HHcy increases arterial permeability by generating O2−to an extent whereby nitric oxide bioavailability is reduced.
Collapse
Affiliation(s)
- Adam E Mullick
- Univ. of Utah School of Medicine, Bldg. 585, Rm. 152, 30 N 2030 E, Salt Lake City, UT 84132 (e-mail )
| | | | | | | | | | | |
Collapse
|
33
|
Ungvari Z, Wolin MS, Csiszar A. Mechanosensitive production of reactive oxygen species in endothelial and smooth muscle cells: role in microvascular remodeling? Antioxid Redox Signal 2006; 8:1121-9. [PMID: 16910760 DOI: 10.1089/ars.2006.8.1121] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Changes in the hemodynamic environment (e.g., hypertension, increased blood flow/shear stress) are known to lead to vascular remodeling; however, the underlying mechanisms by which hemodynamic forces control gene expression in vascular cells are not yet completely understood. This review considers how mechanosensitive generation of reactive oxygen species (ROS) by NAD(P)H oxidases and other sources interacts with downstream signaling systems [including activation of nuclear factor kappa B (NF-kappaB) and AP-1] that modulate the phenotype of endothelial and smooth muscle cells, leading to vascular remodeling. We propose a model for an interaction between direct mechanosensitive ROS signaling and pathways activated by pressure-induced upregulation of prooxidant paracrine signaling mechanisms [local renin-angiotensin system, TNF-alpha- converting enzyme (TACE)/tumor necrosis factor alpha (TNF-alpha) system, and endothelin signaling].
Collapse
Affiliation(s)
- Zoltan Ungvari
- Department of Physiology, New York Medical College, Valhalla, 10595, USA.
| | | | | |
Collapse
|
34
|
Abstract
Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the Western world. Its incidence has been increasing lately in developing countries. Several lines of evidence support a role for oxidative stress in atherogenesis. Growing evidence indicates that chronic and acute overproduction of reactive oxygen species (ROS) under pathophysiologic conditions is integral in the development of cardiovascular diseases (CVD). ROS mediate various signaling pathways that underlie vascular inflammation in atherogenesis from the initiation of fatty streak development through lesion progression to ultimate plaque rupture. Various animal models of oxidative stress support the notion that ROS have a causal role in atherosclerosis and other cardiovascular diseases. Human investigations also support the oxidative stress hypothesis of atherosclerosis. Oxidative stress is the unifying mechanism for many CVD risk factors, which additionally supports its central role in CVD. A main source of ROS in vascular cells is the reduced nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide phosphate (NAD(P)H) oxidase system. This is a membrane-associated enzyme, composed of five subunits, catalyzing the one-electron reduction of oxygen, using NADH or NADPH as the electron donor. This system is an important target for genetic investigations. Identification of groups of patients with genetically prone or resistant of oxidative stress is therefore an obvious target of investigation. A better understanding of the complexity of cellular redox reactions, development of a new class of antioxidants targeted to specific subcellular sites, and the phenotype-genotype linkage analysis for oxidative stress will likely be avenues for future research with regards to the broader use of pharmacological therapies in the treatment and prevention of CVD.
Collapse
Affiliation(s)
- Uma Singh
- The Laboratory for Atherosclerosis and Metabolic Research, UC Davis Medical Center, Sacramento, CA, United States
| | | |
Collapse
|
35
|
Kennedy RH, Owings R, Joseph J, Melchert RB, Hauer-Jensen M, Boerma M. ACUTE DILATORY AND NEGATIVE INOTROPIC EFFECTS OF HOMOCYSTEINE ARE INHIBITED BY AN ADENOSINE BLOCKER. Clin Exp Pharmacol Physiol 2006; 33:340-4. [PMID: 16620298 DOI: 10.1111/j.1440-1681.2006.04372.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
1. Previous studies have shown that homocysteine elicits acute negative inotropic and coronary vasodilatory effects in rat hearts. In addition, this earlier work suggested that the inotropic action is mediated via an endothelium-derived agent that is neither nitric oxide (NO) nor a cyclooxygenase product, while the coronary actions were found to be antagonized by the NOS inhibitor l-NNA. Current experiments, which utilized coronary-perfused rat hearts, were designed to determine if muscarinic or adenosine receptors are involved in these acute actions of homocysteine. 2. Left ventricular developed pressure was used as a measure of systolic function in electrically paced, Langendorff-perfused heart with coronary pressure being used to monitor coronary vascular tone. Acute effects of homocysteine (10-300 micromol/L) were examined in the presence and absence of 1 yen 10(-6) mol atropine or 7 yen 10(-5) mol 8-(p-sulfophenyl) theophylline (SPT), a non-selective adenosine receptor antagonist. 3. Atropine had no effect on either the inotropic or vascular actions of homocysteine. In contrast, SPT partially antagonized both actions of the amino acid with the antagonism of the vasodilation being much greater than its inhibition of the negative inotropic effect. Experiments with adenosine demonstrated that the selected dose of SPT elicited marked rightward shifts in the dose-response curves for both the inotropic and vascular actions. 4. Current results suggest that adenosine plays a role in both the negative inotropic and vasodilatory actions of homocysteine. However, the relatively minor antagonistic action of SPT on the inotropic effect of homocysteine suggests that additional endothelium-derived mediators underlie its effects on contractility.
Collapse
Affiliation(s)
- Richard H Kennedy
- Department of Pharmaceutical Sciences and Pharmacology & Toxicology, University of Arkansas for Medical Sciences, Arkansas, USA.
| | | | | | | | | | | |
Collapse
|
36
|
Labinskyy N, Csiszar A, Veress G, Stef G, Pacher P, Oroszi G, Wu J, Ungvari Z. Vascular dysfunction in aging: potential effects of resveratrol, an anti-inflammatory phytoestrogen. Curr Med Chem 2006; 13:989-96. [PMID: 16611080 PMCID: PMC2228263 DOI: 10.2174/092986706776360987] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Epidemiological studies demonstrated that even in the absence of other risk factors (e.g. diabetes, hypertension, hyperhomocysteinemia, hypercholesterolemia), advanced age itself significantly increases cardiovascular morbidity by enhancing vascular oxidative stress and inflammation. Because the population in the Western world is rapidly aging, there is a substantial need for pharmacological interventions that delay the functional decline of the cardiovascular system. Resveratrol is an atoxic phytoestrogen found in more than 70 plants including grapevine and berries. Recent data suggest that nutritional intake of resveratrol and other polyphenol compounds may contribute to the "French paradox", the unexpectedly low cardiovascular morbidity in the Mediterranean population. There is increasing evidence that resveratrol exerts multifaceted anti-oxidant and/or anti-inflammatory effects in various disease models. Importantly, resveratrol was reported to slow aging and increase lifespan in simple organisms and has been suggested as a potential calorie restriction mimetic. Resveratrol has also been reported to activate NAD-dependent histone deacetylases (sirtuins), which may contribute to its anti-aging effects. This review focuses on the role of oxidative stress and inflammation in cardiovascular dysfunction in aging, and on emerging anti-aging therapeutic strategies offered by resveratrol and other polyphenol compounds.
Collapse
Affiliation(s)
- Nazar Labinskyy
- Department of Physiology, New York Medical College, Valhalla, New York 10595, USA
| | - Anna Csiszar
- Department of Physiology, New York Medical College, Valhalla, New York 10595, USA
| | - Gabor Veress
- State Hospital for Cardiology, Balatonfured 8230, Hungary
| | - Gyorgyi Stef
- State Hospital for Cardiology, Balatonfured 8230, Hungary
| | - Pal Pacher
- Laboratory of Physiological Studies and Neurogenetics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892-9413, USA
| | - Gabor Oroszi
- Laboratory of Physiological Studies and Neurogenetics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892-9413, USA
| | - Joseph Wu
- Department of Biochemistry, New York Medical College, Valhalla, New York 10595, USA
| | - Zoltan Ungvari
- Department of Physiology, New York Medical College, Valhalla, New York 10595, USA
| |
Collapse
|
37
|
Sen U, Moshal KS, Tyagi N, Kartha GK, Tyagi SC. Homocysteine-induced myofibroblast differentiation in mouse aortic endothelial cells. J Cell Physiol 2006; 209:767-74. [PMID: 16972260 DOI: 10.1002/jcp.20752] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Differentiation of myofibroblast, as evidenced by alpha-smooth muscle actin (alpha-SMA) expression, is largely mediated by transforming growth factor-beta1 (TGF-beta1). This mechanism often follows inflammatory events such as endothelial damage due to oxidative stress, which can further leads to vascular thickening, stiffness, and fibrosis. We hypothesized that hyperhomocysteinemia (HHcy)-induced oxidative stress lead to vascular stiffness, in part due to endothelial-myofibroblast differentiation and alteration of collagen homeostasis in the extracellular matrix (ECM). We tested our hypothesis in vitro using mouse aortic endothelial cells (MAEC). Our result shows that Hcy induces alpha-SMA and collagen type-1 expression in MAEC as evidenced by immunoblot and confocal imaging. RT-PCR shows robust increase of alpha-SMA and collagen type-1 mRNA level in Hcy-induced condition. We demonstrated that Hcy induces autophosphorylation of focal adhesion kinase (FAK) (a member of the protein tyrosine kinase (PTK) family) at Tyr-397. PP2 (general PTK inhibitor) as well as FAK siRNA abrogates Hcy-mediated alpha-SMA formation. In addition to that, Hcy-mediated TGF-beta1 induction was inhibited by TGF-beta R1 kinase inhibitor II (ALK5 inhibitor II) and attenuated FAK phosphorylation and alpha-SMA expression. Furthermore, we showed that Hcy activates ERK-44/42 (extracellular signal-regulated kinase) pathway and augments collagen type-1 deposition. Studies with pharmacological ERK blocker, PD98059 and ERK siRNA attenuated ERK-44/42 phosphorylation and collagen type-1 synthesis. Taken together our results demonstrate that Hcy-mediated TGF-beta1 upregulation triggers endothelial-myofibroblast differentiation secondary to FAK phosphorylation and that Hcy-induced ERK activation is involved in ECM remodeling by altering collagen type-1 homeostasis.
Collapse
Affiliation(s)
- Utpal Sen
- Department of Physiology & Biophysics, HSC, University of Louisville School of Medicine, 500 South Preston St., Louisville, KY 40202, USA
| | | | | | | | | |
Collapse
|
38
|
Moshal KS, Sen U, Tyagi N, Henderson B, Steed M, Ovechkin AV, Tyagi SC. Regulation of homocysteine-induced MMP-9 by ERK1/2 pathway. Am J Physiol Cell Physiol 2005; 290:C883-91. [PMID: 16251475 DOI: 10.1152/ajpcell.00359.2005] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Homocysteine (Hcy) induces matrix metalloproteinase (MMP)-9 in microvascular endothelial cells (MVECs). We hypothesized that the ERK1/2 signaling pathway is involved in Hcy-mediated MMP-9 expression. In cultured MVECs, Hcy induced activation of ERK, which was blocked by PD-98059 and U0126 (MEK inhibitors). Pretreatment with BAPTA-AM, staurosporine (PKC inhibitor), or Gö6976 (specific inhibitor for Ca(2+)-dependent PKC) abrogated ERK phosphorylation, suggesting the role of Ca(2+) and Ca(2+)-dependent PKC in Hcy-induced ERK activation. ERK phosphorylation was suppressed by pertussis toxin (PTX), suggesting the involvement of G protein-coupled receptors (GPCRs) in initiating signal transduction by Hcy and leading to ERK activation. Pretreatment of MVECs with genistein, BAPTA-AM, or thapsigargin abrogated Hcy-induced ERK activation, suggesting the involvement of the PTK pathway in Hcy-induced ERK activation, which was mediated by intracellular Ca(2+) pool depletion. ERK activation was attenuated by preincubation with N-acetylcysteine (NAC) and SOD, suggesting the role of oxidation in Hcy-induced ERK activation. Pretreatment with an ERK1/2 blocker (PD-98059), staurosporine, folate, or NAC modulated Hcy-induced MMP-9 activation as measured using zymography. Our results provide evidence that Hcy triggers the PTX-sensitive ERK1/2 signaling pathway, which is involved in the regulation of MMP-9 in MVECs.
Collapse
Affiliation(s)
- Karni S Moshal
- Department of Physiology and Biophysics, University of Louisville School of Medicine, A-1115, 500 S. Preston St., Louisville, KY 40202, USA
| | | | | | | | | | | | | |
Collapse
|
39
|
Symons JD, Rutledge JC, Simonsen U, Pattathu RA. Vascular dysfunction produced by hyperhomocysteinemia is more severe in the presence of low folate. Am J Physiol Heart Circ Physiol 2005; 290:H181-91. [PMID: 16143648 DOI: 10.1152/ajpheart.00765.2005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Earlier we reported that dietary folate depletion causes hyperhomocysteinemia (HHcy) and arterial dysfunction in rats (Symons JD, Mullick AE, Ensunsa JL, Ma AA, and Rutledge JC. Arterioscler Thromb Vasc Biol 22: 772-780, 2002). Both HHcy and low folate (LF) are risk factors for cardiovascular disease. Therefore, the dysfunction we observed could have resulted from HHcy, LF, and/or their combination (HHcy + LF). We tested the hypothesis that HHcy-induced vascular dysfunction is more severe in the presence of LF. Four groups of rats consumed diets for approximately 10 wk that produced plasma homocysteine (microM) and liver folate (microg folate/g liver) concentrations, respectively, of 7 +/- 1 and 15 +/- 1 (Control; Con; n = 16), 17 +/- 2 and 15 +/- 2 (HHcy; n = 17), 10 +/- 1 and 8 +/- 1 (LF; n = 14), and 21 +/- 2 and 8 +/- 1 (HHcy + LF; n = 18). We observed that maximal ACh-evoked vasorelaxation was greatest in aortas and mesenteric arteries from Con rats vs. all groups. While the extent of dysfunction was similar between LF and HHcy animals, it was less severe compared with arteries from HHcy + LF rats. Maximal ACh-evoked vasorelaxation in coronary arteries was not different between Con and LF rats, but both were greater than HHcy + LF animals. In segments of aortas, 1) ACh-evoked vasorelaxation was similar among groups after incubation with the nonenzymatic intracellular O2(-) scavenger Tiron, 2) vascular O2(-) estimated using dihydroethidium staining was greatest in HHcy + LF vs. all groups, and 3) tension development in response to nitric oxide (NO) synthase inhibition was greatest in Con vs. all other groups. We conclude that HHcy + LF evokes greater dysfunction than either HHcy alone (aortas, mesentery) or LF alone (aortas, mesentery, coronary), likely by producing more O2(-) within the vasculature and thereby reducing NO bioavailability.
Collapse
Affiliation(s)
- J David Symons
- College of Health, Univ. of Utah, Salt Lake City, UT, USA.
| | | | | | | |
Collapse
|
40
|
Jones RWA, Jeremy JY, Koupparis A, Persad R, Shukla N. Cavernosal dysfunction in a rabbit model of hyperhomocysteinaemia. BJU Int 2005; 95:125-30. [PMID: 15638909 DOI: 10.1111/j.1464-410x.2004.05263.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To investigate the effect of sustained hyperhomocysteinaemia (HHCy) on cavernosal smooth muscle function in a rabbit model of HHCy, developed using a methionine-enriched diet in which cavernosal responses were characterized, as elevated plasma levels of homocysteine may be a risk factor for vasculogenic erectile dysfunction. MATERIALS AND METHODS Six New Zealand White rabbits were fed a diet supplemented with methionine (20 g/kg chow) for 4 weeks, while six control animals were fed a standard diet. Cavernosal strips were mounted in an organ bath and relaxation assessed when stimulated with carbachol, sodium nitroprusside (SNP), or noncholinergic, nonadrenergic (NANC)-mediated relaxation to electrical-field stimulation (EFS). Cavernosal tissue cGMP levels were assessed using an enzyme-linked immunosorbent assay, and superoxide (O(2) (.-)) production assessed using an assay of the superoxide dismutase (SOD)-inhibitable reduction of ferricytochrome c. RESULTS The methionine-rich diet led to an early but sustained HHCy; cavernosal strips from animals after 4 weeks of HHCy had a significantly impaired relaxation response to carbachol, an index of endothelium-dependent nitric oxide (NO)-mediated relaxation. This impairment was reversed by incubating with either SOD or catalase. Relaxation with either SNP, an index of endothelium-independent NO-mediated relaxation, or NANC-mediated EFS-induced relaxation, was unaffected by HHCy. There was a corresponding significant reduction in cavernosal cGMP levels (index of NO activity) in the HHCy group, with a more than five-fold increase in cavernosal tissue O(2) (.-) production. CONCLUSION Supplementing the diet of rabbits with methionine for 4 weeks caused an early and sustained HHCy and promoted a marked inhibitory effect on endothelium-dependent relaxation and NO formation in isolated corpus cavernosum, an effect mediated by reactive oxygen species.
Collapse
Affiliation(s)
- Robert W A Jones
- Bristol Heart Institute, Royal Infirmary, University of Bristol, Bristol BS2 8HW, UK
| | | | | | | | | |
Collapse
|
41
|
Koller A, Bagi Z. Nitric oxide and H2O2 contribute to reactive dilation of isolated coronary arterioles. Am J Physiol Heart Circ Physiol 2004; 287:H2461-7. [PMID: 15319207 DOI: 10.1152/ajpheart.00295.2004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The role of metabolic factors derived from cardiac muscle in the development of reactive hyperemia after brief occlusions of the coronary circulation seems to be well established. However, the contribution of occlusion-induced changes in hemodynamic forces to eliciting reactive hyperemia is less known. We hypothesized that in isolated coronary arterioles changes in intraluminal pressure and flow, during and after release of occlusion (O/R), themselves via activating intrinsic mechanosensitive mechanisms, elicit release of vasoactive factors resulting in reactive dilations. Thus in isolated coronary arterioles (diameter: 88 ± 8 μm) changes in diameter to changes in pressure or pressure plus flow (P+F) during and after a brief period (30, 60, and 120 s) of O/R of cannulating tube were measured by videomicroscopy. In response to both types of O/R, diameter first decreased, then, subsequently increased during occlusions. When only pressure was changed (from 80-10-80 mmHg), after release of occlusion, peak dilations increased as a function of the duration of occlusions. After flow was established (30 μl/min), O/R elicited changes in both pressure and flow (from 80-10-80 mmHg and from 0 to 30 μl/min). In these conditions, after the release of occlusions, not only the peak but also the duration of reactive dilation increased significantly as a function of the length of occlusions. The dilations during, and peak dilations after occlusions both in pressure and P+F protocols were significantly reduced by the inhibition of NO synthase with Nω-nitro-l-arginine-methyl-ester (l-NAME) or by endothelium removal, whereas duration of postocclusion dilations were reduced by l-NAME or by endothelium removal only in P+F protocols. Furthermore, in both protocols, catalase significantly reduced the peak but not the duration of reactive dilations. Thus, mechanosensitive mechanisms that are sensitive to deformation, pressure, stretch, and wall shear stress elicit release of NO and H2O2, resulting in reactive dilation of isolated coronary arterioles.
Collapse
Affiliation(s)
- Akos Koller
- Dept. of Physiology, New York Medical College, Valhalla, NY 10595, USA.
| | | |
Collapse
|
42
|
Ungvari Z, Csiszar A, Kaminski PM, Wolin MS, Koller A. Chronic high pressure-induced arterial oxidative stress: involvement of protein kinase C-dependent NAD(P)H oxidase and local renin-angiotensin system. THE AMERICAN JOURNAL OF PATHOLOGY 2004; 165:219-26. [PMID: 15215177 PMCID: PMC1618527 DOI: 10.1016/s0002-9440(10)63290-7] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Regardless of the underlying pathological mechanisms oxidative stress seems to be present in all forms of hypertension. Thus, we tested the hypothesis that chronic presence of high pressure itself elicits increased arterial O(2)(.-) production. Hypertension was induced in rats by abdominal aortic banding (Ab). Rats with Ab had elevated pressure in vessels proximal and normal pressure in vessels distal to the coarctation, yet both vascular beds were exposed to the same circulating factors. Compared to normotensive hind limb arteries (HLAs) hypertensive forelimb arteries (FLAs) exhibited 1) impaired dilations to acetylcholine and the nitric oxide donor S-nitroso-N-acetyl-D,L-penicillamine that were restored by administration of superoxide dismutase; 2) an increased production of O(2)(.-) (measured by lucigenin chemiluminescence and ethidium bromide fluorescence) that was inhibited or reduced by superoxide dismutase, the NAD(P)H oxidase inhibitors diphenyleneiodonium and apocynin, or the protein kinase C (PKC) inhibitors chelerythrine and staurosporine or by the angiotensin-converting enzyme (ACE) inhibitor captopril; and 3) increased ACE activity. In organ culture, exposure of isolated arteries of normotensive rats to high pressure (160 mmHg, for 24 hours) significantly increased O(2)(.-) production compared to that in arteries exposed to 80 mmHg. High pressure-induced O(2)(.-) generation was reduced by inhibitors of ACE and PKC. Incubation of cultured arteries with angiotensin II elicited significantly increased O(2)(.-) generation that was inhibited by chelerythrine. Thus, we propose that chronic presence of high pressure itself can elicit arterial oxidative stress, primarily by activating directly a PKC-dependent NAD(P)H oxidase pathway, but also, in part, via activation of the local renin-angiotensin system.
Collapse
Affiliation(s)
- Zoltan Ungvari
- Department of Physiology, Basic Sciences Building, New York Medical College, Valhalla, NY 10595, USA
| | | | | | | | | |
Collapse
|
43
|
Topal G, Brunet A, Millanvoye E, Boucher JL, Rendu F, Devynck MA, David-Dufilho M. Homocysteine induces oxidative stress by uncoupling of NO synthase activity through reduction of tetrahydrobiopterin. Free Radic Biol Med 2004; 36:1532-41. [PMID: 15182855 DOI: 10.1016/j.freeradbiomed.2004.03.019] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2004] [Revised: 03/17/2004] [Accepted: 03/26/2004] [Indexed: 01/18/2023]
Abstract
Hyperhomocysteinemia is a risk factor for cardiovascular diseases that induces endothelial dysfunction. Here, we examine the participation of endothelial NO synthase (eNOS) in the homocysteine-induced alterations of NO/O(2)(-) balance in endothelial cells from human umbilical cord vein. When cells were treated for 24 h, homocysteine dose-dependently inhibited thrombin-activated NO release without altering eNOS phosphorylation and independently of the endogenous NOS inhibitor, asymmetric dimethylarginine. The inhibitory effect of homocysteine on NO release was associated with increased production of reactive nitrogen and oxygen species (RNS/ROS) independent of extracellular superoxide anion (O(2)(-)) and was suppressed by the NOS inhibitor L-NAME. In unstimulated cells, L-NAME markedly decreased RNS/ROS formation and the ethidium red fluorescence induced by homocysteine. This eNOS-dependent O(2)(-) synthesis was associated with reduced intracellular levels of both total biopterins (-45%) and tetrahydrobiopterin (-80%) and increased release of 7,8-dihydrobiopterin and biopterin in the extracellular medium (+40%). In addition, homocysteine suppressed the activating effect of sepiapterin on NO release, but not that of ascorbate. The results show that the oxidative stress and inhibition of NO release induced by homocysteine depend on eNOS uncoupling due to reduction of intracellular tetrahydrobiopterin availability.
Collapse
Affiliation(s)
- Gökce Topal
- Département de Signalisation cellulaire et athérosclérose précoce, UMR CNRS 7131- Université Paris 6, Hôpital Broussais, 102 rue Didot, 75014 Paris, France
| | | | | | | | | | | | | |
Collapse
|
44
|
Julien C, Bayat S, Sam B, Lévy P, Patrick L. Vascular reactivity to norepinephrine and acetylcholine after chronic intermittent hypoxia in mice. Respir Physiol Neurobiol 2003; 139:21-32. [PMID: 14637307 DOI: 10.1016/j.resp.2003.09.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
This study assessed the early vascular reactivity changes in mice after exposure to 14 days intermittent hypoxia (IH) with active or inactive sympathetic nervous system (SNS). Hindquarters of mice exposed to 14 days of IH, sham exposed mice or unhandled mice were perfused at constant flow with Krebs-Albumin (5%). Changes in perfusion pressure were assessed after injection of several doses of norepinephrine in anaesthetized mice (active SNS) or in euthanized mice (inactive SNS). Response to several doses of acetylcholine was recorded after precontraction of hindquarter vascular bed by methoxamine in euthanized mice. Vasoconstrictor response was increased after IH for high dose of NE (50 microg) in euthanized mice and for all doses of NE (2-10-50 microg) in anaesthetized mice, but no change in vasodilatation was observed. These findings suggest that 14 days of IH altered vascular reactivity of mice hindquarter in an early pattern. Vasoconstriction was enhanced, particularly with active SNS, while there was no dysfunction of endothelium-relaxation.
Collapse
Affiliation(s)
- C Julien
- Laboratoire Hypoxie: Physiopathologie, Faculté de Médecine, 38700 Grenoble, France.
| | | | | | | | | |
Collapse
|
45
|
Bagi Z, Cseko C, Tóth E, Koller A. Oxidative stress-induced dysregulation of arteriolar wall shear stress and blood pressure in hyperhomocysteinemia is prevented by chronic vitamin C treatment. Am J Physiol Heart Circ Physiol 2003; 285:H2277-83. [PMID: 12869370 DOI: 10.1152/ajpheart.00448.2003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We aimed to test the hypothesis that an enhanced level of reactive oxygen species (ROS) is primarily responsible for the impairment of nitric oxide (NO)-mediated regulation of arteriolar wall shear stress (WSS) in hyperhomocysteinemia (HHcy). Thus flow/WSS-induced dilations of pressurized gracilis muscle arterioles (basal diameter: approximately 170 microm) isolated from control (serum Hcy: 6 +/- 1 microM), methionine diet-induced HHcy rats (4 wk, serum Hcy: 30 +/- 6 microM), and HHcy rats treated with vitamin C, a known antioxidant (4 wk, 150 mg. kg body wt-1.day-1; serum Hcy: 32 +/- 10 microM), were investigated. In vessels of HHcy rats, increases in intraluminal flow/WSS-induced dilations were converted to constrictions. Constrictions were unaffected by inhibition of NO synthesis by N omega-nitro-L-arginine methyl ester (L-NAME). Vitamin C treatment of HHcy rats reversed the WSS-induced arteriolar constrictions to L-NAME-sensitive dilations but did not affect control responses. Similar changes in responses were obtained for the calcium ionophore A-23187. In addition, diastolic and mean arterial blood pressure and serum 8-isoprostane levels (a marker of in vivo oxidative stress) were significantly elevated in rats with HHcy, changes that were normalized by vitamin C treatment. Taken together, our data show that in chronic HHcy long-term vitamin C treatment, by decreasing oxidative stress in vivo, enhanced NO bioavailability, restored the regulation of shear stress in arterioles, and normalized systemic blood pressure. Thus our study provides evidence that oxidative stress is an important in vivo mechanism that is primarily responsible for the development of endothelial dysregulation of WSS in HHcy.
Collapse
Affiliation(s)
- Zsolt Bagi
- Department of Physiology, New York Medical College, Valhalla, NY 10595, USA
| | | | | | | |
Collapse
|
46
|
Achike FI, Kwan CY. Nitric oxide, human diseases and the herbal products that affect the nitric oxide signalling pathway. Clin Exp Pharmacol Physiol 2003; 30:605-15. [PMID: 12940876 DOI: 10.1046/j.1440-1681.2003.03885.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
1. Nitric oxide (NO) is formed enzymatically from l-arginine in the presence of nitric oxide synthase (NOS). Nitric oxide is generated constitutively in endothelial cells via sheer stress and blood-borne substances. Nitric oxide is also generated constitutively in neuronal cells and serves as a neurotransmitter and neuromodulator in non-adrenergic, non-cholinergic nerve endings. Furthermore, NO can also be formed via enzyme induction in many tissues in the presence of cytokines. 2. The ubiquitous presence of NO in the living body suggests that NO plays an important role in the maintenance of health. Being a free radical with vasodilatory properties, NO exerts dual effects on tissues and cells in various biological systems. At low concentrations, NO can dilate the blood vessels and improve the circulation, but at high concentrations it can cause circulatory shock and induce cell death. Thus, diseases can arise in the presence of the extreme ends of the physiological concentrations of NO. 3. The NO signalling pathway has, in recent years, become a target for new drug development. The high level of flavonoids, catechins, tannins and other polyphenolic compounds present in vegetables, fruits, soy, tea and even red wine (from grapes) is believed to contribute to their beneficial health effects. Some of these compounds induce NO formation from the endothelial cells to improve circulation and some suppress the induction of inducible NOS in inflammation and infection. 4. Many botanical medicinal herbs and drugs derived from these herbs have been shown to have effects on the NO signalling pathway. For example, the saponins from ginseng, ginsenosides, have been shown to relax blood vessels (probably contributing to the antifatigue and blood pressure-lowering effects of ginseng) and corpus cavernosum (thus, for the treatment of men suffering from erectile dysfunction; however, the legendary aphrodisiac effect of ginseng may be an overstatement). Many plant extracts or purified drugs derived from Chinese medicinal herbs with proposed actions on NO pathways are also reviewed.
Collapse
Affiliation(s)
- Francis I Achike
- Clinical Sciences Section, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
| | | |
Collapse
|
47
|
Ungvari Z, Csiszar A, Edwards JG, Kaminski PM, Wolin MS, Kaley G, Koller A. Increased superoxide production in coronary arteries in hyperhomocysteinemia: role of tumor necrosis factor-alpha, NAD(P)H oxidase, and inducible nitric oxide synthase. Arterioscler Thromb Vasc Biol 2003; 23:418-24. [PMID: 12615666 DOI: 10.1161/01.atv.0000061735.85377.40] [Citation(s) in RCA: 215] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE In coronary arteries, hyperhomocysteinemia (HHcy, a known risk factor for coronary heart disease) impairs flow-induced dilations, which can be reversed by superoxide dismutase (SOD). To evidence increased O2*- generation and elucidate its source, we characterized changes in activity (lucigenin chemiluminescence, hydroethidine staining) and expression of arterial pro- and antioxidant systems (Western blotting, immunohistochemistry, cDNA microarray, reverse-transcription polymerase chain reaction) in the coronary arteries of rats by using methionine diet-induced HHcy. METHODS AND RESULTS The increased generation of O2*- by HHcy coronary arteries was inhibited by SOD, diphenyleneiodonium, apocynin, and apocynin plus amino guanidine but was unaffected by allopurinol and rotenone. Also, diphenyleneiodonium-sensitive NADPH-driven O2*- generation was increased in HHcy vessels. In HHcy arteries expression of the smooth muscle-confined NAD(P)H oxidase subunit nox1 and that of iNOS was increased. Expression of p67phox, p22phox, and p47phox subunits and that of endothelial nitric oxide synthase, Cu,Zn-SOD, Mn-SOD, extracellular SOD (mRNA), and xanthine oxidase was unchanged. Microarray analysis showed increased expression of tumor necrosis factor (TNF)-alpha (confirmed by reverse-transcription polymerase chain reaction, Western blotting, and immunohistochemistry) that was localized in smooth muscle. In vitro incubation (18 hours) of HHcy arteries with anti-TNF-alpha antibody decreased O2*- production, whereas incubation of control vessels with TNF-alpha increased O2*- generation and nox1 expression. CONCLUSIONS In coronary arteries, HHcy increases TNF-alpha expression, which enhances oxidative stress through upregulating a nox1-based NAD(P)H oxidase and inducible nitric oxide synthase. Thus, TNF-alpha induces a proinflammatory vascular phenotype in HHcy that potentially contributes to the development of coronary atherosclerosis.
Collapse
Affiliation(s)
- Zoltan Ungvari
- Department of Physiology, New York Medical College, Valhalla, NY 10595, USA
| | | | | | | | | | | | | |
Collapse
|
48
|
|
49
|
Stanger O, Weger M. Interactions of Homocysteine, Nitric Oxide, Folate and Radicals in the Progressively Damaged Endothelium. Clin Chem Lab Med 2003; 41:1444-54. [PMID: 14656024 DOI: 10.1515/cclm.2003.222] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The endothelium exerts fundamental control over vascular tone, and injury to the endothelium followed by dysfunction is an early key event preceding manifestation of vessel pathology. Both elevated plasma homocysteine and low folate status have been identified as major and independent risk factors for atherosclerosis and have stirred an enormous and still increasing interest. The damaging effects of hyperhomocysteinemia on endothelial function are, at least in part, reversible through folate supplementation. Because of the inverse relationship between plasma folate and homocysteine levels, however, it is difficult to discriminate between their respective effects. Endothelial dysfunction refers mainly to reduced bioavailability of nitric oxide (NO), which is involved in homocysteinemediated vascular damage. Accumulating evidence further suggests that radical oxygen species are fundamentally involved in hyperhomocysteinemia. NO production is determined by cofactors such as tetrahydrobiopterin, which is oxidized and depleted in conditions of oxidant stress by peroxynitrite. Deficiency of tetrahydrofolate contributes to uncoupling, turning the NO synthase into a superoxide radical-producing enzyme. It appears that progression of vascular disease is likely to determine the multiple interactions between homocysteine, NO, oxygen radicals and folate. Folate has only recently been found to exert direct anti-oxidative effects and contribute to restoration of impaired NO metabolism. Understanding of the complex interactions between homocysteine, radicals, NO and folate offers promising perspectives in the individual treatment of vascular disease. Thus, preventive and therapeutic strategies may require a more distinct approach and better discrimination of target groups for greatest possible efficacy.
Collapse
Affiliation(s)
- Olaf Stanger
- St. John's Hospital, School of Medicine, Department of Cardiac Surgery, Salzburg, Austria.
| | | |
Collapse
|