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Dardi P, dos Reis Costa D, Assunção H, Rossoni L. Venous endothelial function in cardiovascular disease. Biosci Rep 2022; 42:BSR20220285. [PMID: 36281946 PMCID: PMC9685499 DOI: 10.1042/bsr20220285] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 10/20/2022] [Accepted: 10/24/2022] [Indexed: 09/29/2023] Open
Abstract
The essential role of the endothelium in vascular homeostasis is associated with the release of endothelium-dependent relaxing and contractile factors (EDRF and EDCF, respectively). Different from arteries, where these factors are widely studied, the vasoactive factors derived from the venous endothelium have been given less attention. There is evidence for a role of the nitric oxide (NO), endothelium-dependent hyperpolarization (EDH) mechanism, and cyclooxygenase (COX)-derived metabolites as EDRFs; while the EDCFs need to be better evaluated since no consensus has been reached about their identity in venous vessels. The imbalance between the synthesis, bioavailability, and/or action of EDRFs and/or EDCFs results in a pathological process known as endothelial dysfunction, which leads to reduced vasodilation and/or increased vasoconstriction. In the venous system, endothelial dysfunction is relevant since reduced venodilation may increase venous tone and decrease venous compliance, thus enhancing mean circulatory filling pressure, which maintains or modify cardiac workload contributing to the etiology of cardiovascular diseases. Interestingly, some alterations in venous function appear at the early stages (or even before) the establishment of these diseases. However, if the venous endothelium dysfunction is involved in these alterations is not yet fully understood and requires further studies. In this sense, the present study aims to review the current knowledge on venous endothelial function and dysfunction, and the general state of the venous tone in two important cardiovascular diseases of high incidence and morbimortality worldwide: hypertension and heart failure.
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Affiliation(s)
- Patrizia Dardi
- Laboratory of Vascular Physiology, Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Brazil
| | | | - Henrique Charlanti Reis Assunção
- Laboratory of Vascular Physiology, Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Brazil
| | - Luciana Venturini Rossoni
- Laboratory of Vascular Physiology, Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Brazil
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Kraler S, Libby P, Evans PC, Akhmedov A, Schmiady MO, Reinehr M, Camici GG, Lüscher TF. Resilience of the Internal Mammary Artery to Atherogenesis: Shifting From Risk to Resistance to Address Unmet Needs. Arterioscler Thromb Vasc Biol 2021; 41:2237-2251. [PMID: 34107731 PMCID: PMC8299999 DOI: 10.1161/atvbaha.121.316256] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Fueled by the global surge in aging, atherosclerotic cardiovascular disease reached pandemic dimensions putting affected individuals at enhanced risk of myocardial infarction, stroke, and premature death. Atherosclerosis is a systemic disease driven by a wide spectrum of factors, including cholesterol, pressure, and disturbed flow. Although all arterial beds encounter a similar atherogenic milieu, the development of atheromatous lesions occurs discontinuously across the vascular system. Indeed, the internal mammary artery possesses unique biological properties that confer protection to intimal growth and atherosclerotic plaque formation, thus making it a conduit of choice for coronary artery bypass grafting. Its endothelium abundantly expresses nitric oxide synthase and shows accentuated nitric oxide release, while its vascular smooth muscle cells exhibit reduced tissue factor expression, high tPA (tissue-type plasminogen activator) production and blunted migration and proliferation, which may collectively mitigate intimal thickening and ultimately the evolution of atheromatous plaques. We aim here to provide insights into the anatomy, physiology, cellular, and molecular aspects of the internal mammary artery thereby elucidating its remarkable resistance to atherogenesis. We propose a change in perspective from risk to resilience to decipher mechanisms of atheroresistance and eventually identification of novel therapeutic targets presently not addressed by currently available remedies.
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Affiliation(s)
- Simon Kraler
- Center for Molecular Cardiology, University of Zürich, 8952 Schlieren, Switzerland
| | - Peter Libby
- Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, USA
| | - Paul C. Evans
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Alexander Akhmedov
- Center for Molecular Cardiology, University of Zürich, 8952 Schlieren, Switzerland
| | - Martin O. Schmiady
- Clinic for Cardiac Surgery, University Heart Centre, University Hospital Zurich, Zurich, Switzerland
| | - Michael Reinehr
- Institute of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland
| | - Giovanni G. Camici
- Center for Molecular Cardiology, University of Zürich, 8952 Schlieren, Switzerland
- University Heart Center, Department of Cardiology, University Hospital, Zurich, Switzerland
- Department of Research and Education, University Hospital Zurich, Zurich, Switzerland
| | - Thomas F. Lüscher
- Center for Molecular Cardiology, University of Zürich, 8952 Schlieren, Switzerland
- Royal Brompton and Harefield Hospitals and Imperial College, London, United Kingdom
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Kelham M, Choudry FA, Hamshere S, Beirne AM, Rathod KS, Baumbach A, Ahluwalia A, Mathur A, Jones DA. Therapeutic Implications of COVID-19 for the Interventional Cardiologist. J Cardiovasc Pharmacol Ther 2020; 26:203-216. [PMID: 33331160 DOI: 10.1177/1074248420982736] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Although COVID-19 is viewed primarily as a respiratory disease, cardiovascular risk factors and disease are prevalent among infected patients and are associated with worse outcomes. In addition, among multiple extra-pulmonary manifestations, there has been an increasing recognition of specific cardiovascular complications of COVID-19. Despite this, in the initial stages of the pandemic there was evidence of a reduction in patients presenting to acute cardiovascular services. In this masterclass review, with the aid of 2 exemplar cases, we will focus on the important therapeutic implications of COVID-19 for interventional cardiologists. We summarize the existing evidence base regarding the varied cardiovascular presentations seen in COVID-19 positive patients and the prognostic importance and potential mechanisms of acute myocardial injury in this setting. Importantly, through the use of a systematic review of the literature, we focus our discussion on the observed higher rates of coronary thrombus burden in patients with COVID-19 and acute coronary syndromes.
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Affiliation(s)
- Matthew Kelham
- Department of Cardiology, 560754Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom
| | - Fizzah A Choudry
- Department of Cardiology, 560754Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom.,Centre for Cardiovascular Medicine and Devices, William Harvey Research Institute, 4617Queen Mary University of London, London, United Kingdom
| | - Stephen Hamshere
- Department of Cardiology, 560754Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom
| | - Anne-Marie Beirne
- Department of Cardiology, 560754Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom.,Centre for Cardiovascular Medicine and Devices, William Harvey Research Institute, 4617Queen Mary University of London, London, United Kingdom
| | - Krishnaraj S Rathod
- Department of Cardiology, 560754Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom.,Centre for Cardiovascular Medicine and Devices, William Harvey Research Institute, 4617Queen Mary University of London, London, United Kingdom
| | - Andreas Baumbach
- Department of Cardiology, 560754Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom.,Centre for Cardiovascular Medicine and Devices, William Harvey Research Institute, 4617Queen Mary University of London, London, United Kingdom
| | - Amrita Ahluwalia
- Centre for Cardiovascular Medicine and Devices, William Harvey Research Institute, 4617Queen Mary University of London, London, United Kingdom
| | - Anthony Mathur
- Department of Cardiology, 560754Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom.,Centre for Cardiovascular Medicine and Devices, William Harvey Research Institute, 4617Queen Mary University of London, London, United Kingdom
| | - Daniel A Jones
- Department of Cardiology, 560754Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom.,Centre for Cardiovascular Medicine and Devices, William Harvey Research Institute, 4617Queen Mary University of London, London, United Kingdom
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Libby P, Lüscher T. COVID-19 is, in the end, an endothelial disease. Eur Heart J 2020; 41:3038-3044. [PMID: 32882706 PMCID: PMC7470753 DOI: 10.1093/eurheartj/ehaa623] [Citation(s) in RCA: 621] [Impact Index Per Article: 155.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/07/2020] [Accepted: 07/17/2020] [Indexed: 12/12/2022] Open
Abstract
The vascular endothelium provides the crucial interface between the blood compartment and tissues, and displays a series of remarkable properties that normally maintain homeostasis. This tightly regulated palette of functions includes control of haemostasis, fibrinolysis, vasomotion, inflammation, oxidative stress, vascular permeability, and structure. While these functions participate in the moment-to-moment regulation of the circulation and coordinate many host defence mechanisms, they can also contribute to disease when their usually homeostatic and defensive functions over-reach and turn against the host. SARS-CoV-2, the aetiological agent of COVID-19, causes the current pandemic. It produces protean manifestations ranging from head to toe, wreaking seemingly indiscriminate havoc on multiple organ systems including the lungs, heart, brain, kidney, and vasculature. This essay explores the hypothesis that COVID-19, particularly in the later complicated stages, represents an endothelial disease. Cytokines, protein pro-inflammatory mediators, serve as key danger signals that shift endothelial functions from the homeostatic into the defensive mode. The endgame of COVID-19 usually involves a cytokine storm, a phlogistic phenomenon fed by well-understood positive feedback loops that govern cytokine production and overwhelm counter-regulatory mechanisms. The concept of COVID-19 as an endothelial disease provides a unifying pathophysiological picture of this raging infection, and also provides a framework for a rational treatment strategy at a time when we possess an indeed modest evidence base to guide our therapeutic attempts to confront this novel pandemic.
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Affiliation(s)
- Peter Libby
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Thomas Lüscher
- Heart Division, Royal Brompton & Harefield Hospital and National Heart and Lung Institute, Imperial College, London, UK
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Jeong HS, Hong SJ, Cho SA, Kim JH, Cho JY, Lee SH, Joo HJ, Park JH, Yu CW, Lim DS. Comparison of Ticagrelor Versus Prasugrel for Inflammation, Vascular Function, and Circulating Endothelial Progenitor Cells in Diabetic Patients With Non-ST-Segment Elevation Acute Coronary Syndrome Requiring Coronary Stenting: A Prospective, Randomized, Crossover Trial. JACC Cardiovasc Interv 2018; 10:1646-1658. [PMID: 28838475 DOI: 10.1016/j.jcin.2017.05.064] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 04/05/2017] [Accepted: 05/04/2017] [Indexed: 12/23/2022]
Abstract
OBJECTIVES This study compared adenosine-associated pleiotropic effects of the 2 P2Y12 receptor antagonists on vascular function, systemic inflammation, and circulating endothelial progenitor cells (EPCs). BACKGROUND Both ticagrelor and prasugrel have potent antiplatelet effects. However, only ticagrelor inhibits cellular uptake of adenosine. METHODS Using a randomized, crossover design with 10-week follow-up ticagrelor or prasugrel was administered to type 2 diabetic patients with non-ST-segment elevation acute coronary syndrome requiring stent implantation. A total of 62 patients underwent randomization in a 1:1 ratio to receive ticagrelor or prasugrel for 5 weeks followed by a direct cross over to the alternative treatment for 5 additional weeks. Brachial artery flow-mediated dilation, inflammatory markers, and number of circulating EPCs were compared. RESULTS Improvement in brachial artery flow-mediated dilation was greater in the ticagrelor group (0.15 ± 0.19 mm vs. -0.03 ± 0.18 mm; p < 0.001). Moreover, ticagrelor compared with prasugrel decreased interleukin 6 (-0.58 ± 0.43 pg/ml vs. -0.05 ± 0.24 pg/ml; p < 0.001), tumor necrosis factor alpha (-5.62 ± 4.40 pg/ml vs. -0.42 ± 2.64 pg/ml; p < 0.001), and increased adiponectin (2.31 ± 2.00 μg/ml vs. 0.08 ± 1.50 μg/ml; p < 0.001) during 10-week follow-up. Other inflammatory cytokines like high-sensitivity C-reactive protein and soluble vascular cell adhesion molecule-1 were decreased in both groups. Ticagrelor compared with prasugrel significantly increased absolute numbers of circulating EPCs CD34+/KDR+ (42.5 ± 37.8 per μl vs. -28.2 ± 23.7 per μl; p < 0.001), CD34+/CD117+ (51.9 ± 77.2 per μl vs. -66.3 ± 45.2 per μl; p < 0.001), and CD34+/CD133+ (55.2 ± 69.2 per μl vs. -28.0 ± 34.1 per μl; p < 0.001). CONCLUSIONS Compared with prasugrel, ticagrelor significantly decreased inflammatory cytokines such as interleukin 6 and tumor necrosis factor alpha and increased circulating EPCs, contributing to improved arterial endothelial function in diabetic non-ST-segment elevation acute coronary syndrome patients. Thus, data support that pleiotropic effects of ticagrelor beyond its potent antiplatelet effects could contribute to additional clinical benefits. (Comparison of Ticagrelor vs. Prasugrel on Inflammation, Arterial Stiffness, Endothelial Function, and Circulating Endothelial Progenitor Cells in Diabetic Patients With Non-ST Elevation Acute Coronary Syndrome [NSTE-ACS] Requiring Coronary Stenting; NCT02487732).
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Affiliation(s)
- Han Saem Jeong
- Department of Cardiology, Cardiovascular Center, Korea University Anam Hospital, Seoul, Republic of Korea
| | - Soon Jun Hong
- Department of Cardiology, Cardiovascular Center, Korea University Anam Hospital, Seoul, Republic of Korea.
| | - Sang-A Cho
- Department of Cardiology, Cardiovascular Center, Korea University Anam Hospital, Seoul, Republic of Korea
| | - Jong-Ho Kim
- Department of Cardiology, Cardiovascular Center, Korea University Anam Hospital, Seoul, Republic of Korea
| | - Jae Young Cho
- Department of Cardiology, Cardiovascular Center, Korea University Anam Hospital, Seoul, Republic of Korea
| | - Seung Hun Lee
- Department of Cardiology, Cardiovascular Center, Korea University Anam Hospital, Seoul, Republic of Korea
| | - Hyung Joon Joo
- Department of Cardiology, Cardiovascular Center, Korea University Anam Hospital, Seoul, Republic of Korea
| | - Jae Hyoung Park
- Department of Cardiology, Cardiovascular Center, Korea University Anam Hospital, Seoul, Republic of Korea
| | - Cheol Woong Yu
- Department of Cardiology, Cardiovascular Center, Korea University Anam Hospital, Seoul, Republic of Korea
| | - Do-Sun Lim
- Department of Cardiology, Cardiovascular Center, Korea University Anam Hospital, Seoul, Republic of Korea
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Kafian S, Mobarrez F, Kalani M, Wallén H, Samad BA. Comparison of venous and arterial blood sampling for the assessment of platelet aggregation with whole blood impedance aggregometry. Scandinavian Journal of Clinical and Laboratory Investigation 2011; 71:637-40. [PMID: 21870998 DOI: 10.3109/00365513.2011.604731] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Platelet monitoring is presently under evaluation in the clinic as a tool to improve antiplatelet treatment in patients with coronary artery disease (CAD). Measuring platelet function has, however, many inherent problems. It is important not only to evaluate the method used, but also to evaluate and standardize sampling and sample handling. As platelet monitoring is often performed in connection to coronary angiography and percutaneous coronary interventions, arterial sampling may be more convenient. However, in the outpatient follow-up setting venous sampling is, for obvious reasons, more practical and convenient. In the present study we compared platelet aggregation in blood collected from the arterial sheath to blood collected from the antecubital vein using multiple electrode aggregometry in whole blood in 28 patients with CAD. We found that sampling from artery and vein give similar data and that an identical number of patients with insufficient antiplatelet responses ('low responders' to aspirin and clopidogrel, respectively, according to predefined criteria) were detected with respect to adenosine diphosphate induced and arachidonic-acid induced aggregation. Thus both arterial and venous blood samples can be used in the monitoring of platelet function when multiple electrode aggregometry is applied to detect 'low responders'.
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Affiliation(s)
- Sam Kafian
- Department of Clinical Sciences, Danderyd Hospital, Division of Cardiovascular Medicine, Karolinska Institutet, Stockholm, Sweden
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7
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Miller V. Endothelium-derived factors of veins: Implications in development of venous disease. Int J Angiol 2011. [DOI: 10.1007/bf01616679] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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9
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Walpoth BH, Schmid M, Schwab A, Bosshard A, Eckstein F, Carrel T, Hess OM. Vascular adaptation of the internal thoracic artery graft early and late after bypass surgery. J Thorac Cardiovasc Surg 2008; 136:876-83. [DOI: 10.1016/j.jtcvs.2008.05.029] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2007] [Revised: 04/18/2008] [Accepted: 05/19/2008] [Indexed: 11/15/2022]
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10
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Francia P, Ricotta A, Cosentino F, Volpe M. Vascular Senescence at the Crossroad between Oxidative Stress and Nitric Oxide Pathways. High Blood Press Cardiovasc Prev 2008. [DOI: 10.2165/00151642-200815010-00004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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11
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Miller VM, Jayachandran M, Heit JA, Owen WG. Estrogen therapy and thrombotic risk. Pharmacol Ther 2006; 111:792-807. [PMID: 16473411 DOI: 10.1016/j.pharmthera.2006.01.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2005] [Accepted: 01/04/2006] [Indexed: 11/25/2022]
Abstract
Post-menopausal hormone therapy increases the risk for venous thrombosis, and possibly myocardial infarction (MI) and ischemic stroke. However, most women using hormone therapy do not suffer thrombosis, and to date our ability to identify women at risk is limited. Thrombosis, arterial or venous, has 2 requisites: a vascular anomaly and a response of the hemostasis system to the anomaly. Consequently, experimental approaches to understand the pathophysiology of thrombosis require definition of vascular anatomy and function as well as characteristics of the blood within the context of genetic background, lifestyle choices and environmental exposures, which influence gene expression. Defining interactions among factors that affect individual propensity to thrombosis will allow physicians to better identify at-risk individuals, for example a woman contemplating estrogen therapy for symptoms of menopause, and prevent adverse thrombotic events.
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Affiliation(s)
- Virginia M Miller
- Department of Surgery, Mayo Clinic College of Medicine, Rochester, MN 55905, United States.
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Masood I, Porter KE, London NJM. Endothelin-1 is a mediator of intimal hyperplasia in organ culture of human saphenous vein. Br J Surg 2005. [DOI: 10.1046/j.1365-2168.1997.02597.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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13
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Robson SC, Sévigny J, Imai M, Guckelberger O, Enjyoji K. Thromboregulatory potential of endothelial CD39/nucleoside triphosphate diphosphohydrolase: modulation of purinergic signalling in platelets. ACTA ACUST UNITED AC 2005. [DOI: 10.1517/14728222.4.2.155] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Sharma AK, McGlynn S, Apple S, Pinnow E, Canos DA, Gevorkian N, Tebeica M, Gruberg L, Pichard AD, Lindsay J. Clinical outcomes following stent implantation in internal mammary artery grafts. Catheter Cardiovasc Interv 2003; 59:436-41. [PMID: 12891602 DOI: 10.1002/ccd.10580] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We evaluated our experience with percutaneous coronary intervention (PCI) of internal mammary artery (IMA) grafts. From the institution's database we identified 288 patients with 311 IMA lesions. Of these, 82 (26.4%) had stents placed during PCI. Angiographic success was 92%. Mortality at 1 month was 1.7%, myocardial infarction (MI) 15.7%, and target lesion revascularization (TLR) 0.4%. Cumulative 1-year event rates were mortality 6.4%, MI 20.4%, and TLR 8.0%. TLR rates were significantly higher in the stented lesions than lesions treated with angioplasty alone (19.2% vs. 4.9%; P = 0.004). The higher TLR rate in stented lesions was most apparent at the anastomotic site (25.0% vs. 4.2%; P = 0.006). Percutaneous revascularization of IMA grafts can be performed safely with high procedural success and excellent short- and long-term results. Stenting, particularly at the anastomotic site, was associated with significantly greater rates of TLR than angioplasty alone.
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Affiliation(s)
- Arvind K Sharma
- Department of Cardiology, Washington Hospital Center, Washington, DC 20010, USA
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Amoroso G, van Veldhuisen DJ, Tio RA, Mariani M. Pathophysiology of vascular endothelium and circulating platelets: implications for coronary revascularisation and treatment. Int J Cardiol 2001; 79:265-75. [PMID: 11461751 DOI: 10.1016/s0167-5273(01)00448-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Constant vasodilatation, inhibition of platelet and leukocyte adhesion, and local thrombolysis are the mechanisms through which an intact endothelial layer exerts its protective action on coronary circulation. A loss in these features is not only the first step in the development of atherosclerosis, but also a potent trigger for complications after revascularisation procedures. Percutaneous coronary interventions, particularly in the course of stenting, induce endothelial injury that can last up to months after the procedure. On the other hand, the preservation of endothelial function appears the best feature of arterial versus venous grafts after coronary bypass surgery. An early diagnosis either by invasive or non-invasive techniques has important implications for prognosis, and endothelial dysfunction can be effectively counteracted by medical treatment (ACE inhibitors, statins). Activated circulating platelets are present in the course of coronary artery disease, increasing the risk of thrombotic occlusion and/or plaque regrowth, after both percutaneous and surgical revascularisation. New antiplatelet agents are under development to reduce endothelium-platelet interaction. On the basis of the latest studies, coronary revascularisation should be integrated in a more complete treatment, which would take into account the complex processes involving the underlying atherosclerotic plaque.
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Affiliation(s)
- G Amoroso
- Thoraxcenter, University Hospital of Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands.
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Haefliger IO, Flammer J, Bény JL, Lüscher TF. Endothelium-dependent vasoactive modulation in the ophthalmic circulation. Prog Retin Eye Res 2001; 20:209-25. [PMID: 11173252 DOI: 10.1016/s1350-9462(00)00020-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The vascular endothelium is strategically located between the circulating blood and the vascular smooth muscle cells. Different agonists or stimuli transported by the circulating blood can trigger the endothelium to release potent relaxing (nitric oxide, prostacyclin, endothelium-derived hyperpolarizing factor) or contracting factors (endothelin, cycloxygenase products). These endothelium-derived vasoactive factors can modulate blood flow locally. Heterogeneity exists from one vascular bed to the other, or even between vessels, in the agonists able to stimulate the release of endothelium-derived vasoactive factors. In the ophthalmic circulation, nitric oxide and endothelin are strong vasoactive modulators. In many vascular diseases that are of importance in ophthalmology (hypercholesterolemia, arteriosclerosis, hypertension, diabetes, vasospastic syndrome, ischemia and reperfusion, etc) the function of the endothelium can be impaired. There exist different drugs that can modulate the vasoactive function of the vascular endothelium. In other words, it appears that the vascular endothelium plays an important role in both the physiology and pathophysiology of the regulation of blood flow. The modulation of this regulatory system by different drugs might open new therapeutical approaches to treat vascular disorders in ophthalmology.
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Affiliation(s)
- I O Haefliger
- Laboratory of Ocular Pharmacology and Physiology, University Eye Clinic, Basel, Switzerland
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Yang Z, Kozai T, van der Loo B, Viswambharan H, Lachat M, Turina MI, Malinski T, Lüscher TF, van de Loo B. HMG-CoA reductase inhibition improves endothelial cell function and inhibits smooth muscle cell proliferation in human saphenous veins. J Am Coll Cardiol 2000; 36:1691-7. [PMID: 11079678 DOI: 10.1016/s0735-1097(00)00924-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVES This study examined effects of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase inhibitor cerivastatin on human saphenous vein (SV), endothelial cells (EC) and smooth muscle cells (SMC). BACKGROUND Venous bypass graft failure involves EC dysfunction and SMC proliferation. Substances that improve EC function and inhibit SMC proliferation would be of clinical relevance. METHODS Both EC and SMC were isolated from SV. Endothelial nitric oxide synthase (eNOS) expression and nitric oxide (NO) production were analyzed by immunoblotting and porphyrinic microsensor. The SMC proliferation was assayed by 3H-thymidine incorporation. Protein kinases and cell cycle regulators were analyzed by immunoblotting. RESULTS Cerivastatin (10(-9) to 10(-6) mol/liter) enhanced eNOS protein expression and NO release (about two-fold) in EC in response to Ca2+ ionophore (10(-6) mol/liter). This was fully abrogated by the HMG-CoA product mevanolate (2 x 10(-4) mol/liter). In SMC, platelet-derived growth factor (5 ng/ml) enhanced 3H-thymidine incorporation (298 +/- 23%, n = 4), activated cyclin-dependent kinase (Cdk2), phosphorylated Rb and down-regulated p27Kip1 (but not p21CiP1). Cerivastatin reduced the 3H-thymidine incorporation (164 +/- 11%, p < 0.01), inhibited Cdk2 activation and Rb phosphorylation, but did not prevent p27Kip1 down-regulation, nor p42mapk and p70S6K activation. Mevalonate abrogated the effects of cerivastatin on Cdk2 and Rb but only partially rescued the 3H-thymidine incorporation (from 164 +/- 11% to 211 +/- 13%, n = 4, p < 0.01). CONCLUSIONS In humans, SVEC inhibition of HMG-CoA/mevalonate pathway contributes to the enhanced eNOS expression and NO release by cerivastatin, whereas in SMC, inhibition of this pathway only partially explains cerivastatin-induced cell growth arrest. Inhibition of mechanisms other than p42mapk and p70S6K or Cdk2 are also involved. These effects of cerivastatin could be important in treating venous bypass graft disease.
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Affiliation(s)
- Z Yang
- Department of Cardiovascular Research, University Zürich-Irchel, Switzerland
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Armstrong J, Narracott AJ, Milton R, Galea J, Cooper GJ, Lawford PV, Hose DR, Cumberland DC, Holt CM. Development of an ex vivo model to investigate the effects of altered haemodynamics on human bypass grafts. J Med Eng Technol 2000; 24:183-91. [PMID: 11204241 DOI: 10.1080/03091900050204223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The insertion of vein grafts into the arterial circulation may contribute to vessel wall thickening and accelerated atherosclerosis, a common feature of late vein graft failure. We aimed to develop a model suitable for investigation of the effects of altered haemodynamics on human saphenous vein following its implantation into the arterial circulation. Segments of human saphenous vein obtained from patients undergoing coronary artery bypass surgery were sutured at each end to PTFE and placed into a flow system. Pressure and flow rates to stimulate the arterial and venous systems were achieved. A theoretical model of the flow chamber was created and computational fluid dynamics software (FLOTRAN, Swanson Analysis Systems) was used to determine the flow profile within the model. In summary, a flow model has been developed to investigate the effect of altered haemodynamics on the molecular and pathological changes that occur in vein grafts incorporated into the arterial circulation.
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Affiliation(s)
- J Armstrong
- Cardiovascular Research Group, University of Sheffield Division of Clinical Sciences, Northern General Hospital, Sheffield, UK
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19
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MaassenVanDenBrink A, van den Broek RW, de Vries R, Upton N, Parsons AA, Saxena PR. The potential anti-migraine compound SB-220453 does not contract human isolated blood vessels or myocardium; a comparison with sumatriptan. Cephalalgia 2000; 20:538-45. [PMID: 11075836 DOI: 10.1046/j.1468-2982.2000.00078.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The mechanistically novel benzopyran derivative SB-220453, which is undergoing clinical evaluation in migraine, exhibits a high affinity for a selective, but not yet characterized, binding site in the human brain. It inhibits nitric oxide release and cerebral vasodilatation following cortical spreading depression as well as carotid vasodilatation induced by trigeminal nerve stimulation in the cat. The aim of our study was to investigate the contractile properties of SB-220453 on a number of human isolated blood vessels (coronary artery, saphenous vein and middle meningeal artery) as well as atrial and ventricular cardiac trabeculae. While sumatriptan induced marked contractions in three blood vessels investigated, SB-220453 was devoid of any effect. In atrial and ventricular cardiac trabeculae, neither SB-220453 nor sumatriptan displayed a positive or negative inotropic effect. Since SB-220453 did not contract the middle meningeal artery, we conclude that potential anti-migraine effects are not mediated via a direct cerebral vasoconstriction. The lack of activity of SB-220453 in coronary artery, saphenous vein and cardiac trabeculae demonstrates that the compound is unlikely to cause adverse cardiac side-effects.
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Affiliation(s)
- A MaassenVanDenBrink
- Department of Pharmacology, Erasmus University Medical Centre Rotterdam EMCR, The Netherlands
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20
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Gruberg L, Dangas G, Mehran R, Hong MK, Waksman R, Mintz GS, Kent KM, Pichard AD, Satler LF, Lansky AJ, Stone GW, Leon MB. Percutaneous revascularization of the internal mammary artery graft: short- and long-term outcomes. J Am Coll Cardiol 2000; 35:944-8. [PMID: 10732892 DOI: 10.1016/s0735-1097(99)00652-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVES We evaluated the short- and long-term clinical outcomes after percutaneous revascularization of the internal mammary artery (IMA) graft. BACKGROUND Previous reports in a relatively small number of patients have indicated the safety of balloon angioplasty for the treatment of stenoses in the IMA graft. However, the use of alternative interventional techniques and their long-term results have not yet been evaluated. METHODS We analyzed the in-hospital and one-year clinical outcomes of 174 consecutive patients who underwent percutaneous revascularization of 202 lesions located in the IMA graft, by either balloon angioplasty or stenting. RESULTS Anastomotic lesions were evident in 128 cases (63%), and they were more commonly treated with balloon angioplasty (116/128, 91%), whereas lesions located at the ostium (n = 16, 8%) were more frequently treated with stents (11/16, 69%). Procedural success was 97% with excellent in-hospital outcome: 0.6% mortality rate, no Q-wave myocardial infarction (MI) and 0.6% rate of urgent bypass surgery. Cumulative one-year rates were: mortality 4.4%, MI 2.9% and target lesion revascularization (TLR) 7.4%. CONCLUSIONS Revascularization of the IMA graft can be performed safely, with high procedural success and a low rate of in-hospital complications. Long-term follow-up showed very low TLR rate.
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Affiliation(s)
- L Gruberg
- Cardiovascular Research Foundation, New York 10022, USA
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21
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Enjyoji K, Sévigny J, Lin Y, Frenette PS, Christie PD, Esch JS, Imai M, Edelberg JM, Rayburn H, Lech M, Beeler DL, Csizmadia E, Wagner DD, Robson SC, Rosenberg RD. Targeted disruption of cd39/ATP diphosphohydrolase results in disordered hemostasis and thromboregulation. Nat Med 1999; 5:1010-7. [PMID: 10470077 DOI: 10.1038/12447] [Citation(s) in RCA: 430] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
CD39, or vascular adenosine triphosphate diphosphohydrolase, has been considered an important inhibitor of platelet activation. Unexpectedly, cd39-deficient mice had prolonged bleeding times with minimally perturbed coagulation parameters. Platelet interactions with injured mesenteric vasculature were considerably reduced in vivo and purified mutant platelets failed to aggregate to standard agonists in vitro. This platelet hypofunction was reversible and associated with purinergic type P2Y1 receptor desensitization. In keeping with deficient vascular protective mechanisms, fibrin deposition was found at multiple organ sites in cd39-deficient mice and in transplanted cardiac grafts. Our data indicate a dual role for adenosine triphosphate diphosphohydrolase in modulating hemostasis and thrombotic reactions.
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Affiliation(s)
- K Enjyoji
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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22
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Arnet UA, Novosel D, Barton M, Noll G, Ganten D, Lüscher TF. Endothelial dysfunction in the aorta of transgenic rats harboring the mouse Ren-2 gene. ENDOTHELIUM : JOURNAL OF ENDOTHELIAL CELL RESEARCH 1999; 6:175-84. [PMID: 10365769 DOI: 10.3109/10623329909053408] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The renin-angiotensin system plays an important role in the pathophysiology of hypertension. We studied vascular function in the aorta of mouse Ren-2 transgenic rats (TGR(mRen2)27). Changes in isometric tension of isolated aorta of TGR(mRen2)27 and Sprague-Dawley rats (SD) were recorded in organ chambers. Contractions to angiotensin II (AII), big-endothelin and endothelin-1 (ET-1), but not KCl were decreased in TGR. Blockade of nitric oxide (NO)-synthase by L-NAME or removal of the endothelium did not alter these decreased contractions to ET-1 and AII in TGR, suggesting that receptors or signaling pathways of these two agonists are downregulated during hypertension. Contractions to norepinephrine (NE) were also lower in TGR, however blockade of NO-synthase by L-NAME or removal of the endothelium evoked similar contractions to NE in both strains, suggesting that basal release of NO reduces contractions to NE to a greater extent in transgenic than control rats. In the presence of L-NAME, acetylcholine evoked endothelium-dependent contractions (EDCF) in TGR, which were blocked by the thromboxane/prostaglandin H2 receptor antagonists SQ 30741, and partially by the thromboxane synthase inhibitor CGS 13080, suggesting that prostaglandin H2 is the mediator. Endothelium-dependent relaxation to acetylcholine was decreased in TGR, while endothelium-independent relaxations to sodium nitroprusside were similar in both strains. SQ 30741 did not improve relaxations to acetylcholine in TGR indicating that impaired relaxations to acetylcholine are due to a decreased acetylcholine-receptor mediated release of NO rather than increased release of EDCF. Thus, Ren-2 hypertension leads to marked alterations of vascular functions in the aorta. These changes could contribute to hypertension and its vascular complications in TGR(mRen2)27 rats.
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Affiliation(s)
- U A Arnet
- Cardiology, Laboratory of Cardiovascular Research, Inselspital, Bern, Germany
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23
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Bishop-Bailey D, Pepper JR, Larkin SW, Mitchell JA. Differential induction of cyclooxygenase-2 in human arterial and venous smooth muscle: role of endogenous prostanoids. Arterioscler Thromb Vasc Biol 1998; 18:1655-61. [PMID: 9763540 DOI: 10.1161/01.atv.18.10.1655] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Two isoforms of cyclooxygenase (COX) have been identified: a constitutive isoform (COX-1), found in abundance in platelets and the vascular endothelium, and an "inflammatory" cytokine-inducible isoform (COX-2). Because COX metabolites regulate vascular smooth muscle cell (SMC) function and the interaction between the vessel and circulating components, we have investigated the possibility that COX-2 can be induced in human arterial or venous SMC. Untreated venous or arterial cells contained undetectable levels of COX-1 or COX-2 and released low levels of metabolites. After stimulation with interleukin-1beta, tumor necrosis factor-alpha, interferon-gamma, and bacterial lipopolysaccharide, both venous and arterial SMC expressed COX-2 protein and released increased amounts of prostaglandins. In addition, the induced release of PGE2 was inhibited by the COX-2-selective inhibitor, L-745,337. When cells were treated with the mixture of cytokines, venous SMC expressed greater amounts of COX-2 protein and released more prostaglandins than arterial SMC. Furthermore, when COX-2 activity was blocked by L-745,337, COX-2 expression in arterial SMC, but not in venous SMC, increased. Thus, this article describes, for the first time, that COX-2 is expressed in greater amounts in venous SMC than in arterial SMC. Moreover, we show that this "differential induction" is due to a negative-feedback pathway for COX-2 expression in arterial SMC but not in venous SMC. The ability of COX-2 activity to limit COX-2 expression in some cells but not others may contribute to the highly developed mechanisms involved in prostanoid release.
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Affiliation(s)
- D Bishop-Bailey
- Department of Applied Pharmacology, The National Heart and Lung Institute, Imperial College of Science and Technology, London, UK
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24
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Salas E, Langford EJ, Marrinan MT, Martin JF, Moncada S, de Belder AJ. S-nitrosoglutathione inhibits platelet activation and deposition in coronary artery saphenous vein grafts in vitro and in vivo. Heart 1998; 80:146-50. [PMID: 9813560 PMCID: PMC1728774 DOI: 10.1136/hrt.80.2.146] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE To investigate platelet activation and deposition in human saphenous vein and internal mammary artery grafts following coronary artery bypass in vitro and in vivo, as well as inhibition of activation by the platelet selective nitric oxide donor S-nitrosoglutathione (GSNO). DESIGN Controlled in vitro and in vivo studies. SETTING Tertiary cardiac centre. PATIENTS 24 patients undergoing coronary artery bypass surgery requiring vein and artery grafts. INTERVENTIONS In vitro: human platelet rich plasma was perfused through segments of vein and artery, with or without GSNO 10(-6) M, and the platelet count was measured in the effluent. In vivo: indium-111 labelled antibody against the platelet alpha granule protein GMP-140 was injected at the end of coronary bypass grafting and gamma counts were compared between vein and artery grafts with or without systemic infusion of GSNO (40 nmol/min). RESULTS In vitro: platelet count in perfused vein (< 70% of baseline) decreased more than in artery segments (89-94% of baseline) (p < 0.001). The platelet count was unchanged with GSNO in vein and artery segments. In vivo: gamma counts were greater at all time points over vein than artery grafts (p < 0.05), and were reduced by infusion of GSNO (p < 0.05). CONCLUSIONS Platelet activation is greater in vein than in artery grafts in vitro and in vivo. Activation, which contributes to early vein graft failure, was inhibited by GSNO.
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Affiliation(s)
- E Salas
- Department of Gynecology, Obstetrics and Pharmacology, University of Alberta, Edmonton, Canada
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25
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Toes GJ, van Geel PP, van den Dungen JJ, Buikema H, Grandjean JG, Verhoeven EL, van Oeveren W, Timens W. The use of the gastroepiploic artery for peripheral revascularisation. A study in pigs. Eur J Vasc Endovasc Surg 1998; 15:320-6. [PMID: 9610344 DOI: 10.1016/s1078-5884(98)80035-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVES To use the autologous gastroepiploic artery (GEA) as arterial bypass graft for peripheral revascularisation. We compared the development of intimal hyperplasia and nitric oxide (NO) capacity in GEA and internal jugular vein (IJV) implanted as peripheral grafts. MATERIALS AND METHODS In pigs the GEA was implanted into the right peripheral circulation as a femoropopliteal bypass graft. In the left peripheral circulation the IJV was implanted as a femoropopliteal graft. After 21 days all grafts were harvested. Vascular rings of each graft before and after operation were studied for NO capacity. The distal half of each graft was prepared for histomorphometric studies. RESULTS Administration of bradykinin to IJV and GEA induced relaxation. After implantation bradykinin resulted in contraction in IJV grafts, whereas in GEA grafts relaxation was reduced. In IJV grafts extensive intimal hyperplasia was formed, whereas in GEA grafts only small areas of intimal hyperplasia were formed. CONCLUSIONS The functional studies lost NO capacity in IJV grafts, whereas NO capacity in GEA grafts remained intact. Intimal hyperplasia in IJV grafts was extensive, whereas GEA grafts demonstrated preservation of pre-existent intimal architecture. These results may encourage the application of the human GEA as bypass graft for reconstruction of arteries in the lower limb or foot.
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Affiliation(s)
- G J Toes
- Department of Surgery, University Hospital Groningen, The Netherlands
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26
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Chello M, Mastroroberto P, Perticone F, Celi V, Colonna A. Nitric oxide modulation of neutrophil-endothelium interaction: difference between arterial and venous coronary bypass grafts. J Am Coll Cardiol 1998; 31:823-6. [PMID: 9525554 DOI: 10.1016/s0735-1097(97)00560-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVES This study sought to evaluate the relation between the pattern of neutrophil-endothelial adhesion in saphenous vein (SV) and internal mammary artery (IMA) grafts and the endothelial production of nitric oxide (NO). BACKGROUND Autologous IMA and SV grafts (SVGs) are increasingly used as conduits for coronary bypass grafting. Previous studies have demonstrated a greater production of endothelial-derived relaxing factor (NO) from IMA than from SVGs. Because of the well known role of NO in modulating the adhesion of polymorphonuclear leukocytes to the endothelium, we studied the pattern of neutrophil adhesion to the endothelium of IMA and SVs under basal conditions and after inhibition of NO synthesis. METHODS Segments of IMA and SVs were obtained from 20 patients undergoing coronary artery bypass graft surgery. We evaluated the adhesion of both unstimulated and activated neutrophils to the endothelial surface of IMA and SVs in both basal conditions and after inhibition of NO synthesis with Nomega-nitro-L-arginine methyl ester. RESULTS Under basal conditions, no difference in unstimulated neutrophil adhesion to endothelium was observed between the two vessel conduits. After neutrophil activation, a significantly (p < 0.05) greater adhesion of neutrophils was observed in the SV than in the IMA. After inhibition of NO release, the adhesion of activated neutrophils increased in both vessels, and no significant difference between them was observed. The increased adhesion was attenuated by both L-arginine and sodium nitroprusside. CONCLUSIONS The lesser neutrophil adhesion to the endothelium of the IMA is a consequence of enhanced release of NO at this level; this effect could be responsible for the better early and long-term patency of this conduit over the SVG in coronary bypass grafting.
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Affiliation(s)
- M Chello
- Department of Experimental and Clinical Medicine, Medical School of Catanzaro, Italy.
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27
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Yang Z, Oemar BS, Carrel T, Kipfer B, Julmy F, Lüscher TF. Different proliferative properties of smooth muscle cells of human arterial and venous bypass vessels: role of PDGF receptors, mitogen-activated protein kinase, and cyclin-dependent kinase inhibitors. Circulation 1998; 97:181-7. [PMID: 9445171 DOI: 10.1161/01.cir.97.2.181] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Internal mammary artery (IMA) bypass grafts have a higher patency than saphenous vein (SV) grafts. Intimal hyperplasia of SV grafts is due to smooth muscle cell (SMC) proliferation and migration. We hypothesized that different SMC growth activity exists in IMA and SV, which may explain the different patencies of arterial and venous grafts. METHODS AND RESULTS SMCs were isolated from IMA and SV by explant culture and stimulated with serum or platelet-derived growth factor-BB (PDGF-BB). Cell growth was analyzed by explant outgrowth rate, 3H-thymidine incorporation, or cell counting. PDGF receptor expression and autophosphorylation, regulation of mitogen-activated protein kinases (MAPKs), and cyclin-dependent kinase inhibitors (p27Kip1 and p21Cip1) were analyzed by molecular techniques. SMC outgrowth from explants by serum (20%) over a 20-day period was more pronounced in SV (37+/-5%) than in IMA (4+/-3%; P<.001) of the same patients. Serum (10%) increased cell number more rapidly in SV (2 x 10(4)/well to 18+/-4 x 10(4)/well; P<.05) than in IMA (2 x 10(4)/well to 9+/-4 x 10(4)/well; P<.05) over an 8-day period. PDGF-BB (0.01 to 10 ng/mL) stimulated 3H-thymidine incorporation (1347+/-470% above control levels) and increased cell number in SV (2 x 10(4)/well to 5+/-1 x 10(4)/well; P<.05) but not in IMA. PDGF alpha- and beta-receptors were similarly expressed and were activated in both SV and IMA. PDGF-BB induced a similar MAPK activation (kinetics and maximal activity) in both SV and IMA cells but increased MAPK protein level only in SV. Furthermore, PDGF-BB markedly downregulated the cell cycle inhibitor p27Kip1 in SV, but this was much less pronounced in IMA. CONCLUSIONS SMCs from SVs exhibit enhanced proliferation compared with IMA in spite of functional growth factor receptor expression and MAPK activation. However, PDGF increased MAPK protein level only in SV and downregulated cell cycle inhibitor (p27Kip1) more potently in SV than in IMA. This may explain the resistance to growth stimuli of IMA SMCs and may contribute to the longer patency of arterial versus venous grafts.
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Affiliation(s)
- Z Yang
- Cardiovascular Research, Institute for Physiology, University Zürich-Irchel, Switzerland
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28
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Wever RM, Lüscher TF, Cosentino F, Rabelink TJ. Atherosclerosis and the two faces of endothelial nitric oxide synthase. Circulation 1998; 97:108-12. [PMID: 9443438 DOI: 10.1161/01.cir.97.1.108] [Citation(s) in RCA: 160] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- R M Wever
- Department of Clinical Chemistry, University Hospital Utrecht, The Netherlands
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29
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Abstract
The generation of nitric oxide by the vascular endothelium maintains a continuous vasodilator tone that is essential for the regulation of blood flow and blood pressure. Nitric oxide also contributes to the control of platelet aggregation and has important antiatherogenic effects. These properties are mediated by the action of constitutive nitric oxide synthase and subsequent activation by nitric oxide of soluble guanylate cyclase. Impaired release of nitric oxide occurs in most animal and human models of hypertension, contributing to the increased peripheral resistance and most likely to the development of cardiovascular complications. Antihypertensive medications (angiotensin-converting enzyme [ACE] inhibitors and calcium channel blockers) appear to prevent the impairment of nitric oxide-mediated vasodilation in experimental hypertension, though in humans the data are not as clear. Reduced nitric oxide release appears therefore to be a consequence rather than a cause of high blood pressure, and the reduction in blood pressure per se is most important. In hyperlipidaemia, endothelium-dependent relaxations are reduced probably due to the inhibitory action of oxidized low-density lipoproteins on endothelium-dependent relaxations. Lipid-lowering strategies and, more recently, ACE inhibition have been demonstrated to improve nitric oxide dependent coronary vasodilation in hypercholesterolaemic patients with and without atheromatous coronary disease. Nitric oxide dependent vasodilation is also impaired in insulin- and non-insulin-dependent diabetes as well as in healthy aging. Endothelial dysfunction may be improved in non-insulin-dependent diabetes by administration of the antioxidants, supporting the hypothesis that nitric oxide inactivation by oxygen-derived free radicals contributes to abnormal vascular reactivity in diabetes.
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Affiliation(s)
- D Lyons
- Clinical Age Research Unit, King's College School of Medicine and Dentistry, London, UK.
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30
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Wight E, Noll G, Lüscher TF. Regulation of vascular tone and endothelial function and its alterations in cardiovascular disease. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s0950-3501(97)80041-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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31
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Kauhanen P, Sirén V, Carpén O, Vaheri A, Lepäntalo M, Lassila R. Plasminogen activator inhibitor-1 in neointima of vein grafts: its role in reduced fibrinolytic potential and graft failure. Circulation 1997; 96:1783-9. [PMID: 9323062 DOI: 10.1161/01.cir.96.6.1783] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Intimal smooth muscle cell proliferation is an underlying pathogenetic mechanism for neointimal hyperplasia and consequent vein graft failure. This study characterizes the expression of tissue-type plasminogen activator (TPA), urokinase-type plasminogen activator (UPA), and plasminogen activator inhibitor-1 (PAI-1) in hyperplastic vein grafts and normal venous tissue. METHODS AND RESULTS Failing graft and control vein specimens from 14 donors were homogenized, and TPA and PAI-1 were quantified with ELISA. The amount of PAI-1 was seven times higher (4.2+/-2.1 versus 0.6+/-0.6 ng/mg protein, P<.005), but the TPA antigen content was markedly lower (3.1+/-2.1 versus 8.1+/-3.7 ng/mg protein, P<.005) in the stenosed grafts compared with the control veins. Strong immunohistochemical PAI-1 reactivity and in situ hybridization signals for PAI-1 and UPA mRNA were associated with the smooth muscle cells of the thickened intima of the grafts. Functional assays of the graft specimens showed an increased UPA/TPA ratio and a decreased total fibrinolytic activity in comparison with normal veins. CONCLUSIONS Upregulation of PAI-1 mRNA expression and markedly increased amounts of PAI-1 antigen were detected in the vein grafts after the development of neointima. Furthermore, augmented UPA activity was found in the graft wall, but TPA was clearly depleted. Altogether, our findings imply decreased fibrinolytic potential in the stenosed graft, which may contribute to the graft occlusion.
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Affiliation(s)
- P Kauhanen
- Wihuri Research Institute, Helsinki, Finland
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33
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Lesnikoski BA, Candinas D, Otsu I, Metternich R, Bach FH, Robson SC. Thrombin Inhibition in discordant xenograft rejection. Xenotransplantation 1997. [DOI: 10.1111/j.1399-3089.1997.tb00177.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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34
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Yang Z, Ruschitzka F, Rabelink TJ, Noll G, Julmy F, Joch H, Gafner V, Aleksic I, Althaus U, Lüscher TF. Different effects of thrombin receptor activation on endothelium and smooth muscle cells of human coronary bypass vessels. Implications for venous bypass graft failure. Circulation 1997; 95:1870-6. [PMID: 9107175 DOI: 10.1161/01.cir.95.7.1870] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Thrombin is implicated in coronary bypass graft disease; it cleaves its receptor's extracellular N-terminal domain and unmasks a new N-terminus as a tethered ligand. We studied the effects of thrombin receptor activation in human internal mammary artery (IMA) and saphenous vein (SV). METHODS AND RESULTS To study the effects of thrombin receptor activation on vasomotion, isolated blood vessels were suspended for isometric tension recording, and the effects on cell proliferation were studied in cultured smooth muscle cells (SMCs) of IMA and SV. Thrombin receptor expression in IMA and SV was analyzed by reverse transcription polymerase chain reaction and immunohistology. Receptor function was studied by analyzing the activation of mitogen-activated protein kinase (p42MAPK). In IMA thrombin evoked endothelium-dependent relaxations (65 +/- 5%) that were mimicked by thrombin receptor agonist peptide (TRAP) and reduced by the thrombin inhibitors recombinant (r-) hirudin and D-Phe-Pro-Arg-chloromethyl ketone (PPACK) (P < .05). In SV thrombin caused contractions (36 +/- 5% of 100 mmol/L KCl) that were inhibited by r-hirudin or PPACK (P < .05) but not mimicked by TRAP. In SMCs thrombin induced more pronounced [3H]thymidine incorporation (inhibited by r-hirudin or PPACK) in SV than IMA (P < .05), but activation of p42MAPK was similar in both vessels. TRAP induced weaker activation of p42MAPK than thrombin and did not stimulate [3H]thymidine incorporation in SMCs of SV or IMA. Immunohistology and RT-PCR demonstrated that the endothelium and SMCs of IMA and SV express thrombin receptor. CONCLUSIONS Functional thrombin receptors are present on endothelium and SMCs of IMA and SV. Endothelial thrombin receptors mediate relaxation in IMA but not SV. Thrombin causes much more pronounced contraction and proliferation in SMCs of SV than IMA independent of tethered receptors, suggesting other thrombin receptors exist. These differences of thrombin receptor activation in IMA and SV may be important in the development of and therapy for graft disease.
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Affiliation(s)
- Z Yang
- Department of Cardiology, University Hospital, Inselspital Bern, Switzerland
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35
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Masood I, Porter KE, London NJM. Endothelin-1 is a mediator of intimal hyperplasia in organ culture of human saphenous vein. Br J Surg 1997. [DOI: 10.1002/bjs.1800840418] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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36
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Peltonen S, Lassila R, Lepäntalo M. Increased circulating plasminogen activator inhibitor-1 in patients with patent femoro-distal venous bypass. Thromb Res 1996; 82:369-77. [PMID: 8743732 DOI: 10.1016/0049-3848(96)00086-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Veins used for arterial bypass grafting undergo wall remodeling when exposed to altered flow, which may affect fibrinolytic mechanisms and subsequently the fate of the graft. Our aim was to study the extent of blood coagulation and fibrinolysis activation in 27 patients with patent grafts two years after femoro-distal bypass surgery. The two matched control groups included 10 and 19 conservatively treated patients having similar degree of arterial insufficiency (mean ankle/brachial blood pressure index) as the bypass group pre- and post-operatively, respectively. Plasma samples for coagulation and fibrinolysis activation were determined using ELISA and chromogenic assays. When compared with the control groups circulating tissue-type plasminogen activator antigen, and especially plasminogen activator inhibitor type-1, PAI-1 antigen and activity were significantly increased, the mean increase ranging between 54% and 140% in the bypass group. Thrombin-antithrombin III complex, fibrinogen, and C-reactive protein, did not differ, while triglycerides were elevated in the bypass group. Ten patients in the bypass group were insulin resistant, but this did not explain the differences in the fibrinolytic parameters between the bypassed and control patients. Patients with peripheral vein grafts had upregulation of PAI-1 in their circulation implying reduced fibrinolytic capacity. Increased PAI-1, a risk factor for venous thrombosis, might reflect developing intimal hyperplasia, and it remains to be studied whether upregulation of PAI-1 in venous grafts associates with graft failure.
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Affiliation(s)
- S Peltonen
- Wihuri Research Institute, Helsinki University Central Hospital, Finland
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Dzimiri N, Chester AH, Allen SP, Duran C, Yacoub MH. Vascular reactivity of arterial coronary artery bypass grafts--implications for their performance. Clin Cardiol 1996; 19:165-71. [PMID: 8674250 DOI: 10.1002/clc.4960190307] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Specific properties of the vessel wall of arteries employed as coronary bypass grafts are thought to play an important role in the short- and long-term performance of these conduits. Heterogeneity in the endothelial and smooth muscle cell function between different arteries may provide particular vessels with properties which will favor them for use as bypass conduits. The aim of this review is to provide an insight into how the vascular reactivity of presently used arterial conduits varies and to discuss the clinical implications of these findings both in terms of flow modulation in response to physiologic and exogenous vasoactive mediators and long-term patency.
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Affiliation(s)
- N Dzimiri
- Department of Biological and Medical Research, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
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Nitric Oxide and Endothelial Regulation of Vascular Tone. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s1043-9471(96)80022-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Lüscher TF, Noll G. The pathogenesis of cardiovascular disease: role of the endothelium as a target and mediator. Atherosclerosis 1995. [DOI: 10.1016/0021-9150(95)90076-4] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Drieu la Rochelle C, O'Connor SE. Sumatriptan-induced saphenous venoconstriction in the anaesthetized dog through 5-HT1-like receptor activation. Br J Pharmacol 1995; 116:2207-12. [PMID: 8564250 PMCID: PMC1908983 DOI: 10.1111/j.1476-5381.1995.tb15055.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
1. The role of vasoconstrictor 5-HT1-like receptors in the control of vascular reactivity in vivo has been relatively little studied, particularly with regards to venous function. Using an anaesthetized dog model, we have investigated the haemodynamic profile of the selective 5-HT1-like agonist, sumatriptan, focussing on the reactivity of the saphenous venous bed. The key feature of our experimental model was the implantation of ultrasonic crystals on the adventitial surface of the lateral saphenous vein to provide direct and continuous measurement of drug-induced changes in vein diameter. Saphenous vein pressure was measured simultaneously via a proximal branch. 2. Sumatriptan 1-30 micrograms kg-1, i.v., produced pronounced dose-related reductions in saphenous vein diameter which reached congruent to 40% at the highest dose tested. Sumatriptan also produced modest increases in mean blood pressure, total peripheral resistance and left ventricular end diastolic pressure but had little or no effect on cardiac output, heart rate, cardiac contractility or saphenous venous pressure. Sumatriptan-induced reductions in saphenous vein diameter were strongly antagonized by the 5-HT1-receptor antagonist, methiothepin (0.3 mg kg-1, i.v.) but were unaffected by the 5-HT2 antagonist, ketanserin (0.3 mg kg-1, i.v.). 3. Hence, 5-HT1-like receptor stimulation in vivo can result in a powerful local venoconstrictor effect.
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Allen SP, Chester AH, Dzimiri NF, Duran CM, Yacoub M. Vascular biology of human saphenous veins. Ann Saudi Med 1995; 15:378-84. [PMID: 17590611 DOI: 10.5144/0256-4947.1995.378] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
- S P Allen
- National Heart and Lung Institute, London, Heart Science Centre Harefield Hospital, Harefield, Middlesex, U.K., Department of Cardiovascular Diseases, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
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Gurné O, Chenu P, Polidori C, Louagie Y, Buche M, Haxhe JP, Eucher P, Marchandise B, Schroeder E. Functional evaluation of internal mammary artery bypass grafts in the early and late postoperative periods. J Am Coll Cardiol 1995; 25:1120-8. [PMID: 7897125 DOI: 10.1016/0735-1097(94)00538-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVES We sought to determine whether internal mammary artery grafts adapt to an increase in myocardial flow demand and whether they restore maximal flow reserve. BACKGROUND Although mammary grafts are now considered the graft of choice for coronary artery bypass surgery, there is still controversy about whether they can provide adequate flow at periods of peak myocardial demand. METHODS Of 28 patients with a mammary graft anastomosed to the left anterior descending coronary artery, 15 were studied early (mean [+/- SD] 8 +/- 2 days) and 13 late (19 +/- 15 months) after operation by quantitative angiography and selective intravascular Doppler analysis at baseline, during pacing and after injection of papaverine and isosorbide dinitrate into the graft. Eleven patients with a normal left anterior descending artery served as control subjects. RESULTS At baseline, mean graft diameter (2.39 +/- 0.41 vs. 2.42 +/- 0.45 mm) and bypass flow (38 +/- 22 vs. 30 +/- 12 ml/min) were similar in the early and late postoperative periods. Significant and similar vasodilation was observed in mammary grafts after administration of papaverine (+6 +/- 5% vs. +9 +/- 6%) and nitrates (+14 +/- 7% vs. +16 +/- 9%) both early and late after bypass surgery. Graft diameter increased during pacing late (+6 +/- 3%, p < 0.05) but not early after operation. Bypass flow increased similarly during pacing in both groups, but maximal flow reserve induced by papaverine was significantly lower in mammary grafts studied early (2.70 +/- 0.62) than those studied late (3.66 +/- 0.81, p < 0.01) and in normal coronary arteries (4.05 +/- 0.96, p < 0.001). CONCLUSIONS An increase in myocardial blood flow induced by pacing resulted in vasodilation of mammary grafts in the late but not in the early postoperative period. Significant vasodilation of mammary grafts after papaverine and isosorbide dinitrate administration was observed both early and late after operation. However, bypass flow reserve after papaverine injection was significantly lower in the early postoperative period but normalized over time. This finding seems unrelated to the conduit; rather, it appears to be related to the periphery and could be the result of injury to the microvasculature during operation.
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Affiliation(s)
- O Gurné
- Department of Cardiology, Mont-Godinne Hospital, University of Louvain Medical School, Yvoir, Belgium
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Tabuchi N, Huet RC, Sturk A, Eijsman L, Wildevuur CR. Aprotinin preserves hemostasis in aspirin-treated patients undergoing cardiopulmonary bypass. Ann Thorac Surg 1994; 58:1036-9. [PMID: 7524460 DOI: 10.1016/0003-4975(94)90450-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Various clinical trials have shown that hemostasis is improved by the administration of aprotinin during cardiopulmonary bypass. However, this effect has not been proved for those patients treated preoperatively with aspirin. Therefore, a double-blind, placebo-controlled study was conducted to test the efficacy of low-dose aprotinin (2 x 10(6) KIU in the pump prime solution) in preserving hemostasis in 40 aspirin-treated (325 mg) patients undergoing coronary artery bypass grafting. Aprotinin brought about a decrease in the postoperative blood loss (p < 0.05). The in vitro bleeding test (Thrombostat) demonstrated that aprotinin preserved the platelet hemostatic function in aspirin-treated patients during cardiopulmonary bypass (p < 0.05). The inhibitory effects of aspirin on collagen-induced platelet aggregation and thromboxane production were not influenced by aprotinin treatment. The findings from the present study indicate that aprotinin preserves hemostasis in aspirin-treated patients during cardiopulmonary bypass, but aspirin's effect on platelets is maintained. Therefore, aprotinin seems to be a useful adjunct treatment in aspirin-treated patients undergoing coronary artery bypass grafting.
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Affiliation(s)
- N Tabuchi
- Thorax Center, University Hospital Groningen, The Netherlands
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Underwood MJ, Cooper GJ, de Bono DP. Autogenous arterial grafts for coronary bypass surgery: current status and future perspectives. Int J Cardiol 1994; 46:95-102. [PMID: 7814173 DOI: 10.1016/0167-5273(94)90028-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- M J Underwood
- Department of Cardiac Surgery, Bristol Royal Infirmary, UK
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Haefliger IO, Meyer P, Flammer J, Lüscher TF. The vascular endothelium as a regulator of the ocular circulation: a new concept in ophthalmology? Surv Ophthalmol 1994; 39:123-32. [PMID: 7801220 DOI: 10.1016/0039-6257(94)90157-0] [Citation(s) in RCA: 136] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The endothelium influences local vascular tone by releasing endothelium-derived relaxing factors such as nitric oxide, prostacyclin and a putative hyperpolarizing factor. In isolated ophthalmic arteries and the perfused eye, all endothelial factors importantly contribute to vascular regulation. In larger ophthalmic vessels, this is due to their effects on vascular smooth muscle cells; in smaller vessels, pericytes can be influenced as well. Contracting factors formed include peptide endothelin-1 and cyclooxygenase products, such as thromboxane A2 and prostaglandin H2. In the peripheral circulation endothelial dysfunction occurs under pathological conditions, both in conduit arteries and the microcirculation. An imbalance of endothelium-derived relaxing and contracting factors could be important for the development of vascular ophthalmic complications like hypertension, diabetes, arteriolosclerosis and retinal ischemia. Endothelial dysfunction may also contribute to vasospastic events in retinal migraine and some forms of low tension glaucoma associated with Raynaud phenomenon and migraine.
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Affiliation(s)
- I O Haefliger
- Department of Research, University Hospitals, Basel, Switzerland
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Abstract
In the complex setting of cardiac surgery and cardiopulmonary bypass, several potent mediators are released that by interacting may cause clinical syndromes like coronary ischemia, systemic hypertension, pulmonary hypertension, and renal failure. One of the mediators is serotonin, released from aggregating platelets, and causing vasoconstriction by activating S2-serotonergic receptors, particularly in patients with an impaired endothelial function, as in atherosclerosis. The most important available specific S2-serotonergic receptor antagonist is ketanserin. If administered during or after cardiac surgery, ketanserin lowers systemic and pulmonary blood pressure, and improves peripheral and pulmonary perfusion without causing reflex tachycardia or an increase in pulmonary shunt fraction.
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Affiliation(s)
- P J Van der Starre
- Department of Cardiothoracic Anesthesiology and Intensive Care, Hospital De Weezenlanden, Zwolle, The Netherlands
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Tschudi MR, Noll G, Arnet U, Novosel D, Ganten D, Lüscher TF. Alterations in coronary artery vascular reactivity of hypertensive Ren-2 transgenic rats. Circulation 1994; 89:2780-6. [PMID: 8205692 DOI: 10.1161/01.cir.89.6.2780] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND The renin-angiotensin system and endothelium-derived nitric oxide (EDNO) are important regulators of vascular tone. This study was designed to investigate endothelial and vascular smooth muscle function in coronary arteries of Ren-2 transgenic rats. METHODS AND RESULTS Left anterior descending coronary arteries and aortas were isolated from transgenic rats and Sprague-Dawley control rats at 6 (young) and 12 (adult) weeks of age and examined in myographs or organ chambers for isometric tension recording. Systolic blood pressure was significantly higher in transgenic rats (young, 229 +/- 6 mm Hg; adult, 239 +/- 8 mm Hg) than in control rats (young, 126 +/- 2 mm Hg; adult, 118 +/- 3 mm Hg; P < .005). N omega-Nitro-L-arginine methyl ester (L-NAME, 10(-7) to 10(-4) mol/L) evoked marked endothelium-dependent contractions in coronary arteries (young, 52 +/- 8% of the contraction to 100 mmol/L KCl; adult, 40 +/- 8%) but not aortas (young, 3 +/- 1%; adult, 2 +/- 1%). In coronary arteries, this response was significantly smaller in adult (n = 9) than in young (n = 8, P < .05) control rats. Young transgenic rats (56 +/- 9%, n = 8) showed slightly stronger contractions in response to L-NAME than young control rats (NS), which almost totally disappeared in adult transgenic rats (6 +/- 3%, n = 7; P < .05 versus adult control rats; P < .01 versus young transgenic rats). Endothelium-dependent relaxations in response to acetylcholine (10(-9) to 10(-4) mol/L) were totally blocked by L-NAME (10(-4) mol/L) but were unaffected by the thromboxane receptor antagonist SQ30741 (10(-7) mol/L). This stimulated release of EDNO, endothelium-independent relaxations in response to the nitrovasodilator linsidomine (10(-9) to 10(-5) mol/L), and contractions in response to KCl (100 mmol/L) were comparable in all groups of rats. CONCLUSIONS Ren-2 transgenic rats develop fulminant hypertension that is associated with a selective decrease in endothelium-dependent contractions in response to L-NAME, whereas endothelium-dependent relaxations in response to acetylcholine as well as smooth muscle function remain unaffected.
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Affiliation(s)
- M R Tschudi
- Department of Research, University Hospital Basel, Switzerland
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Yang Z, Arnet U, Bauer E, von Segesser L, Siebenmann R, Turina M, Lüscher TF. Thrombin-induced endothelium-dependent inhibition and direct activation of platelet-vessel wall interaction. Role of prostacyclin, nitric oxide, and thromboxane A2. Circulation 1994; 89:2266-72. [PMID: 8181152 DOI: 10.1161/01.cir.89.5.2266] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND Platelet-vessel wall interaction plays an important role in acute cardiovascular disorders. Thrombin is a potent platelet activator but also has profound effects on the endothelium. Endothelial cells possess antithrombotic activity by releasing nitric oxide and prostacyclin, both potent vasodilators and platelet inhibitors. We studied the role of thrombin as a regulator of platelet-vessel wall interaction in isolated human arteries suspended in organ chambers for isometric tension recording. METHODS AND RESULTS In arteries with endothelium, thrombin (0.01 to 1 U/mL) induced endothelium-dependent relaxations, which were reduced by the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME; 10(-4) mol/L) and/or indomethacin (10(-5) mol/L). Human platelets (75,000/microL) evoked only marginal contractions in arteries with endothelium (3 +/- 3% of the contraction to KCl 100 mmol/L; NS), which were markedly enhanced by endothelial removal (22 +/- 4%; P < .05). Thrombin (1 U/mL) did not affect the response to platelets in arteries with (6 +/- 5%; NS) but induced a huge contraction in rings without endothelium (53 +/- 6%; P < .01 versus control without endothelium). The potent contraction to thrombin-activated platelets (1000 to 75,000/microL) in arteries without endothelium was markedly inhibited by the thromboxane A2 synthetase/receptor antagonist ridogrel (10(-5) mol/L; P < .005 versus control) and the single-acting thromboxane receptor blocker SQ-30741 (10(-7) mol/L; P < .01 versus control). CONCLUSIONS Thus, thrombin directly stimulates platelets to release thromboxane A2, inducing potent vasoconstriction, which is prevented by the simultaneous thrombin-induced release of prostacyclin and nitric oxide from endothelial cells. In arteries devoid of functional endothelial cells, as occurs in patients with coronary artery disease, a combined inhibition of thromboxane production and action provides a potent therapeutic tool to interfere with the thrombin-induced activation of platelet-vessel wall interaction.
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Affiliation(s)
- Z Yang
- Department of Medicine, University Hospitals Basel, Switzerland
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Tschudi MR, Criscione L, Novosel D, Pfeiffer K, Lüscher TF. Antihypertensive therapy augments endothelium-dependent relaxations in coronary arteries of spontaneously hypertensive rats. Circulation 1994; 89:2212-8. [PMID: 8181147 DOI: 10.1161/01.cir.89.5.2212] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND Coronary artery disease is an important complication of hypertension. Therefore, the effects of antihypertensive therapy on the endothelial nitric oxide (NO)/L-arginine pathway and vascular smooth muscle were studied in left anterior descending coronary arteries of Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). Angiotensin II (AT1) receptor antagonists CGP 48369 and valsartan, angiotensin-converting enzyme inhibitor benazepril HCl, and calcium antagonist nifedipine were used as antihypertensive agents. METHODS AND RESULTS Rings were examined in myograph systems for isometric tension recording. In untreated WKY and SHR rings, acetylcholine (10(-9) to 10(-5) mol/L) but not bradykinin, substance P (both 10(-6) mol/L), or thrombin (1 U/mL) induced comparable endothelium-dependent relaxations. These relaxations were markedly decreased by NG-monomethyl-L-arginine (10(-4) mol/L) and fully prevented by N omega-nitro-L-arginine methyl ester (10(-4) mol/L) or methylene blue (10(-5) mol/L). In vitro treatment of WKY and SHR rings with benazeprilat, CGP 48369, or valsartan (3 x 10(-7) mol/L) did not affect responses to acetylcholine. In SHR, chronic therapy for 8 weeks with benazepril HCl, CGP 48369, valsartan, or nifedipine (each 10 mg.kg-1.d-1 PO) similarly reduced blood pressure and increased endothelium-dependent relaxations to acetylcholine (log shift at IC50, ie, half-maximal inhibition of a preceding contraction, 10-, 8-, 13-, and 13-fold, P < .05 versus control), whereas relaxations to the NO donor 3-morpholino sydnonimine (SIN-1, 10(-9) to 10(-5) mol/L) remained unaffected. In WKY, chronic therapy with nifedipine (10 mg.kg-1.d-1 PO) affected neither blood pressure nor relaxations to acetylcholine or SIN-1. CONCLUSIONS In rat coronary arteries, NO is synthesized via the endothelial L-arginine pathway and released after stimulation with acetylcholine. In SHR, chronic antihypertensive therapy with either angiotensin receptor antagonists, an angiotensin-converting enzyme inhibitor, or a calcium antagonist specifically increased the normal endothelium-dependent relaxations to acetylcholine, probably because of their blood pressure-lowering effects, whereas the responsiveness of vascular smooth muscle to NO remained unaffected.
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Affiliation(s)
- M R Tschudi
- Department of Research, University Hospitals Basel, Switzerland
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