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Velagic A, Qin C, Woodman OL, Horowitz JD, Ritchie RH, Kemp-Harper BK. Nitroxyl: A Novel Strategy to Circumvent Diabetes Associated Impairments in Nitric Oxide Signaling. Front Pharmacol 2020; 11:727. [PMID: 32508651 PMCID: PMC7248192 DOI: 10.3389/fphar.2020.00727] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 05/01/2020] [Indexed: 12/19/2022] Open
Abstract
Diabetes is associated with an increased mortality risk due to cardiovascular complications. Hyperglycemia-induced oxidative stress underlies these complications, leading to an impairment in endogenous nitric oxide (NO•) generation, together with reductions in NO• bioavailability and NO• responsiveness in the vasculature, platelets and myocardium. The latter impairment of responsiveness to NO•, termed NO• resistance, compromises the ability of traditional NO•-based therapeutics to improve hemodynamic status during diabetes-associated cardiovascular emergencies, such as acute myocardial infarction. Whilst a number of agents can ameliorate (e.g. angiotensin converting enzyme [ACE] inhibitors, perhexiline, statins and insulin) or circumvent (e.g. nitrite and sGC activators) NO• resistance, nitroxyl (HNO) donors offer a novel opportunity to circumvent NO• resistance in diabetes. With a suite of vasoprotective properties and an ability to enhance cardiac inotropic and lusitropic responses, coupled with preserved efficacy in the setting of oxidative stress, HNO donors have intact therapeutic potential in the face of diminished NO• signaling. This review explores the major mechanisms by which hyperglycemia-induced oxidative stress drives NO• resistance, and the therapeutic potential of HNO donors to circumvent this to treat cardiovascular complications in type 2 diabetes mellitus.
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Affiliation(s)
- Anida Velagic
- Heart Failure Pharmacology, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Central Clinical School, Monash University, Melbourne, VIC, Australia
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
| | - Chengxue Qin
- Heart Failure Pharmacology, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Central Clinical School, Monash University, Melbourne, VIC, Australia
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
| | - Owen L. Woodman
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
| | - John D. Horowitz
- Basil Hetzel Institute, Queen Elizabeth Hospital, University of Adelaide, Adelaide, SA, Australia
| | - Rebecca H. Ritchie
- Heart Failure Pharmacology, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Central Clinical School, Monash University, Melbourne, VIC, Australia
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
- Department of Pharmacology, Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Barbara K. Kemp-Harper
- Department of Pharmacology, Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
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Chen P, Liu H, Xiang H, Zhou J, Zeng Z, Chen R, Zhao S, Xiao J, Shu Z, Chen S, Lu H. Palmitic acid-induced autophagy increases reactive oxygen species via the Ca 2+/PKCα/NOX4 pathway and impairs endothelial function in human umbilical vein endothelial cells. Exp Ther Med 2019; 17:2425-2432. [PMID: 30906429 PMCID: PMC6425131 DOI: 10.3892/etm.2019.7269] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 09/06/2018] [Indexed: 12/14/2022] Open
Abstract
It is well known that the lipotoxic mechanism of palmitic acid (PA), a main constituent of triglyceride, is dependent on reactive oxygen species (ROS). Recently, it has also been reported that PA is an autophagy inducer. However, the causal association and underlying mechanism of induced autophagy and ROS in PA toxicity remain unclear. The present study demonstrates for the first time that PA-induced autophagy enhances ROS generation via activating the calcium ion/protein kinase Cα/nicotinamide adenine dinucleotide phosphate oxidase 4 (Ca2+/PKCα/NOX4) pathway in human umbilical vein endothelial cells (HUVECs). It was revealed that PA treatment resulted in a significant increase in ROS generation and autophagic activity, leading to endothelial dysfunction as indicated by downregulated nitric oxide synthesis, decreased capillary-like structure formation and damaged cell repair capability. Furthermore, PA effectively activated the Ca2+/PKCα/NOX4 pathway, which is indicative of upregulated cytosolic Ca2+ levels, activated PKCα and increased NOX4 protein expression. 3-Methyladenine was then used to inhibit autophagy, which significantly reduced PA-induced ROS generation and blocked the Ca2+/PKCα/NOX4 pathway. The endothelial dysfunction caused by PA was ameliorated by downregulating ROS generation using a NOX4 inhibitor. In conclusion, PA-induced autophagy contributes to endothelial dysfunction by increasing oxidative stress via the Ca2+/PKCα/NOX4 pathway in HUVECs.
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Affiliation(s)
- Pan Chen
- Center for Experimental Medical Research, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China.,Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Hengdao Liu
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Hong Xiang
- Center for Experimental Medical Research, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Jianda Zhou
- Department of Burns, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Zhengpeng Zeng
- Respiratory Medicine, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Ruifang Chen
- Center for Experimental Medical Research, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Shaoli Zhao
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Jie Xiao
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Zhihao Shu
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Shuhua Chen
- Center for Experimental Medical Research, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China.,Department of Biochemistry, School of Life Sciences of Central South University, Changsha, Hunan 410013, P.R. China
| | - Hongwei Lu
- Center for Experimental Medical Research, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China.,Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
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Navia-Pelaez JM, Campos-Mota GP, Araujo de Souza JC, Aguilar EC, Stergiopulos N, Alvarez-Leite JI, Capettini LSA. nNOS uncoupling by oxidized LDL: Implications in atherosclerosis. Free Radic Biol Med 2017; 113:335-346. [PMID: 28970060 DOI: 10.1016/j.freeradbiomed.2017.09.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 09/13/2017] [Accepted: 09/21/2017] [Indexed: 02/03/2023]
Affiliation(s)
- Juliana Maria Navia-Pelaez
- Laboratory of Vascular Biology, Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
| | - Gianne Paul Campos-Mota
- Laboratory of Vascular Biology, Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
| | - Jessica Cristina Araujo de Souza
- Laboratory of Vascular Biology, Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
| | - Edenil Costa Aguilar
- Laboratory of Vascular Biology, Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil; Laboratory of Atherosclerosis and Nutritional Biochemistry, Department of Biochemistry and Immunology, Institute of Biological Sciences, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
| | - Nikos Stergiopulos
- Laboratory of Hemodynamics and Cardiovascular Technology, Institute of Bioengineering, Ecole Polytechnique Federale de Lausanne, BM 5128 Station 17, CH-1015 Lausanne, Switzerland.
| | - Jacqueline Isaura Alvarez-Leite
- Laboratory of Atherosclerosis and Nutritional Biochemistry, Department of Biochemistry and Immunology, Institute of Biological Sciences, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
| | - Luciano Santos Aggum Capettini
- Laboratory of Vascular Biology, Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
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The emerging role of NADPH oxidase NOX5 in vascular disease. Clin Sci (Lond) 2017; 131:981-990. [PMID: 28473473 DOI: 10.1042/cs20160846] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 03/14/2017] [Accepted: 03/19/2017] [Indexed: 01/11/2023]
Abstract
Oxidative stress is a consequence of up-regulation of pro-oxidant enzyme-induced reactive oxygen species (ROS) production and concomitant depletion of antioxidants. Elevated levels of ROS act as an intermediate and are the common denominator for various diseases including diabetes-associated macro-/micro-vascular complications and hypertension. A range of enzymes are capable of generating ROS, but the pro-oxidant enzyme family, nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs), are the only enzymes known to be solely dedicated to ROS generation in the vascular tissues, kidney, aortas and eyes. While there is convincing evidence for a role of NOX1 in vascular and eye disease and for NOX4 in renal injury, the role of NOX5 in disease is less clear. Although NOX5 is highly up-regulated in humans in disease, it is absent in rodents. Thus, so far it has not been possible to study NOX5 in traditional mouse or rat models of disease. In the present review, we summarize and critically analyse the emerging evidence for a pathophysiological role of NOX5 in disease including the expression, regulation and molecular and cellular mechanisms which have been demonstrated to be involved in NOX5 activation.
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Pinheiro LC, Tanus-Santos JE, Castro MM. The potential of stimulating nitric oxide formation in the treatment of hypertension. Expert Opin Ther Targets 2017; 21:543-556. [PMID: 28338370 DOI: 10.1080/14728222.2017.1310840] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Hypertension is a leading cause of morbidity and mortality worldwide. A major pathophysiological factor contributing to hypertension is reduced nitric oxide (NO) bioavailability. Strategies to address this pathophysiological mechanism could offer significant advantages. Areas covered: In this review we aimed at examining a variety of drugs (statins, beta-adrenergic receptor blockers, calcium channel blockers, angiotensin converting enzyme inhibitors, angiotensin II type-1 receptor blockers) used to treat hypertension and other cardiovascular diseases, particularly with respect to their potential of increasing NO bioavailability and activity in the cardiovascular system. There is now evidence supporting the notion that many cardiovascular drugs activate NO signaling or enhance NO bioavailability as a contributing mechanism to their beneficial cardiovascular effects. Moreover, other drugs may attenuate NO inactivation by superoxide and other reactive oxygen species by exerting antioxidant effects. More recently, the NO oxidation products nitrite and nitrate have been acknowledged as sources of NO after recycling back to NO. Activation of the nitrate-nitrite-NO pathway is an alternate pathway that may generate NO from both anions and exert antihypertensive effects. Expert opinion: In this review, we provide an overview of the possible mechanisms by which these drugs enhance NO bioavailability and help in the therapy of hypertension.
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Affiliation(s)
- Lucas C Pinheiro
- a Department of Pharmacology, Ribeirao Preto Medical School , University of Sao Paulo , Ribeirao Preto , Brazil
| | - Jose E Tanus-Santos
- a Department of Pharmacology, Ribeirao Preto Medical School , University of Sao Paulo , Ribeirao Preto , Brazil
| | - Michele M Castro
- a Department of Pharmacology, Ribeirao Preto Medical School , University of Sao Paulo , Ribeirao Preto , Brazil
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Endothelial nitric oxide synthase in the vascular wall: Mechanisms regulating its expression and enzymatic function. Artery Res 2011. [DOI: 10.1016/j.artres.2011.03.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Improving vascular function in hypertension: potential benefits of combination therapy with amlodipine and renin-angiotensin-aldosterone system blockers. J Hypertens 2010; 28:2-8. [PMID: 19797978 DOI: 10.1097/hjh.0b013e328332bcf0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Hypertension is characterized by endothelial dysfunction and increased risk for adverse cardiovascular outcomes. In addition to lowering blood pressure, the calcium-channel blocker amlodipine and blockers of the renin-angiotensin-aldosterone system (angiotensin-converting enzyme inhibitors and angiotensin II type 1 receptor blockers) may further reduce cardiovascular risk by improving endothelial function when used alone or in combination. In fact, the beneficial effects of the combination of amlodipine and a renin-angiotensin-aldosterone system blocker on endothelial function have been found to be greater than the effect of either drug alone, likely due to additive effects on nitric oxide activity. This review summarizes the observed effects of these agents on endothelial function and the complementary mechanisms by which they act, thus providing rationale (beyond blood pressure benefits) for their use in combination.
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Littlejohn TW, Trenkwalder P, Hollanders G, Zhao Y, Liao W. Long-term safety, tolerability and efficacy of combination therapy with aliskiren and amlodipine in patients with hypertension. Curr Med Res Opin 2009; 25:951-9. [PMID: 19257800 DOI: 10.1185/03007990902785845] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Most patients with hypertension require antihypertensive combination therapy to achieve BP control. This study investigated the safety and efficacy of the direct renin inhibitor aliskiren combined with the calcium channel blocker amlodipine. METHODS Overall, 556 patients with hypertension (msDBP > or =95-<110 mmHg) received open-label aliskiren/amlodipine 150/5 mg for 2 weeks, followed by forced titration to aliskiren/amlodipine 300/10 mg for 52 weeks. Add-on hydrochlorothiazide (HCT) was permitted from week 10 to achieve BP control (<140/90 mmHg). The primary objective of the study was to evaluate the long-term safety and tolerability of aliskiren/amlodipine combination therapy; the BP-lowering efficacy of the combination was also assessed (week 54 endpoint; last observation carried forward). TRIAL REGISTRATION ClinicalTrials.gov identifier NCT00402103. RESULTS In total, 452 patients completed 54 weeks' treatment with aliskiren/amlodipine 300/10 mg, with or without add-on HCT. The most frequently reported adverse events (AEs) were peripheral edema, upper respiratory tract infection, headache and bronchitis. Peripheral edema (the most common AE), occurred in 22.7% of treated patients, and was generally mild or moderate in intensity and transient in nature. Few patients exhibited laboratory abnormalities. Aliskiren/amlodipine combination therapy provided a mean BP reduction from baseline to week 54 of 24.2/15.5 mmHg; 74.3% of patients achieved BP control. In the subgroup of patients with stage 2 hypertension (baseline msSBP > or =160 mmHg and/or msDBP > or =100 mmHg), the mean BP reduction at week 54 was 29.1/17.1 mmHg, and 67.0% of patients achieved BP control. CONCLUSION In this open-label study, aliskiren/amlodipine 300/10 mg combination therapy, with or without add-on HCT, effectively reduced BP, particularly in patients with stage 2 hypertension. The most common AE was peripheral edema, consistent with the known AE profile of high-dose (10 mg) amlodipine. Further studies comparing the aliskiren/amlodipine combination with the component monotherapies and other antihypertensive combinations are warranted.
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Guzik TJ, Chen W, Gongora MC, Guzik B, Lob HE, Mangalat D, Hoch N, Dikalov S, Rudzinski P, Kapelak B, Sadowski J, Harrison DG. Calcium-dependent NOX5 nicotinamide adenine dinucleotide phosphate oxidase contributes to vascular oxidative stress in human coronary artery disease. J Am Coll Cardiol 2008; 52:1803-9. [PMID: 19022160 DOI: 10.1016/j.jacc.2008.07.063] [Citation(s) in RCA: 207] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 07/03/2008] [Accepted: 07/14/2008] [Indexed: 11/26/2022]
Abstract
OBJECTIVES This study sought to examine the expression and activity of the calcium-dependent nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) in human atherosclerotic coronary arteries. BACKGROUND The NOX-based NADPH oxidases are major sources of reactive oxygen species (ROS) in human vessels. Several NOX homologues have been identified, but their relative contribution to vascular ROS production in coronary artery disease (CAD) is unclear; NOX5 is a unique homolog in that it is calcium dependent and thus could be activated by vasoconstrictor hormones. Its presence has not yet been studied in human vessels. METHODS Coronary arteries from patients undergoing cardiac transplantation with CAD or without CAD were studied; NOX5 was quantified and visualized using Western blotting, immunofluorescence, and quantitative real-time polymerase chain reaction. Calcium-dependent NADPH oxidase activity, corresponding greatly to NOX5 activity, was measured by electron paramagnetic resonance. RESULTS Both Western blotting and quantitative real-time polymerase chain reaction indicated a marked increase in NOX5 protein and messenger ribonucleic acid (mRNA) in CAD versus non-CAD vessels. Calcium-dependent NADPH-driven production of ROS in vascular membranes, reflecting NOX5 activity, was increased 7-fold in CAD and correlated significantly with NOX5 mRNA levels among subjects. Immunofluorescence showed that NOX5 was expressed in the endothelium in the early lesions and in vascular smooth muscle cells in the advanced coronary lesions. CONCLUSIONS These studies identify NOX5 as a novel, calcium-dependent source of ROS in atherosclerosis.
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Affiliation(s)
- Tomasz J Guzik
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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Hayden MR, Sowers JR. Treating hypertension while protecting the vulnerable islet in the cardiometabolic syndrome. ACTA ACUST UNITED AC 2008; 2:239-66. [PMID: 20409906 DOI: 10.1016/j.jash.2007.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Revised: 12/06/2007] [Accepted: 12/06/2007] [Indexed: 12/19/2022]
Abstract
Hypertension, a multifactorial-polygenic disease, interacts with multiple environmental stressors and results in functional and structural changes in numerous end organs, including the cardiovascular system. This can result in coronary heart disease, stroke, peripheral vascular disease, congestive heart failure, end-stage renal disease, insulin resistance, and damage to the pancreatic islet. Hypertension is the most important modifiable risk factor for major health problems encountered in clinical practice. Whereas hypertension was once thought to be a medical condition based on discrete blood pressure readings, a new concept has emerged defining hypertension as part of a complex and progressive metabolic and cardiovascular disease, an important part of a cardiometabolic syndrome. The central role of insulin resistance, oxidative stress, endothelial dysfunction, metabolic signaling defects within tissues, and the role of enhanced tissue renin-angiotensin-aldosterone system activity as it relates to hypertension and type 2 diabetes mellitus are emphasized. Additionally, this review focuses on the effect of hypertension on functional and structural changes associated with the vulnerable pancreatic islet. Various classes of antihypertensive drugs are reviewed, especially their roles in delaying or preventing damage to the vulnerable pancreatic islet, and thus delaying the development of type 2 diabetes mellitus.
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Affiliation(s)
- Melvin R Hayden
- Departments of Internal Medicine, Endocrinology Diabetes and Metabolism, and Diabetes and Cardiovascular Disease Research Center, School of Medicine, University of Missouri-Columbia, Health Sciences Center, Columbia, Missouri, USA
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&NA;. Prevent aortic complications in patients with Marfan??s syndrome by targeting the underlying histological and haemodynamic abnormalities. DRUGS & THERAPY PERSPECTIVES 2008. [DOI: 10.2165/00042310-200824020-00003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Abstract
The cardiovascular complications of Marfan syndrome (MFS) remain the primary source of morbidity and mortality in affected patients. Over the last decade, the underlying pathogenesis of these cardiovascular abnormalities has been the focus of much research. Such research has shed light on the potential role of several novel medical therapies and their ability to prevent cardiovascular disease progression. This paper summarizes the research underlying new medical therapies and provides a review of the scientific foundation underlying all current medical therapies used for prevention of cardiovascular disease in patients with MFS, including beta-adrenoceptor antagonists, calcium channel antagonists, ACE inhibitors, and angiotensin receptor antagonists.
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Affiliation(s)
- Anji T Yetman
- Department of Pediatric Cardiology, Primary Children's Medical Center, 100 N. Medical Drive, Salt Lake City, UT 84113, USA.
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Abstract
Increasing knowledge of the role of nitric oxide (NO) in physiology and disease has stimulated efforts to target the NO pathway pharmacologically. These therapeutic strategies include NO donors that directly or indirectly release NO and agents that increase NO bioactivity. Traditional organic nitrates such as nitroglycerin, which indirectly release NO, were believed to have limited long-term efficacy and tolerability, chiefly because of nitrate tolerance. Recent studies, however, suggest more effective ways of using these agents and new applications for them. Nicorandil, a hybrid organic nitrate that also activates potassium channels, has demonstrated significant benefits in acute coronary syndromes. Other nitrates are being investigated for use in neurodegenerative diseases. Direct NO donors include NO gas, which is useful in respiratory disorders, and the more recent classes of diazeniumdiolates, sydnonimines, and S-nitrosothiols. Preliminary data suggest that these agents may be effective as antiatherosclerotic agents as well as in other disease states. In addition, hybrid agents that consist of an NO donor coupled with a parent anti-inflammatory drug, including nonsteroidal anti-inflammatory drugs, have demonstrated enhanced efficacy and tolerability compared with the anti-inflammatory parent drug alone in diverse experimental models. Established drugs that enhance NO bioactivity include antihypertensive agents, particularly angiotensin-converting enzyme inhibitors, calcium channel blockers, and newer vasodilating beta-blockers. In addition, 3-methylglutaryl coenzyme A reductase inhibitors (statins) promote NO bioactivity, both through and independent of lipid lowering. The NO-promoting actions of these established drugs provide some insight into their known benefits and suggest possible therapeutic potential.
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Affiliation(s)
- R Preston Mason
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
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Mahrouf M, Ouslimani N, Peynet J, Djelidi R, Couturier M, Therond P, Legrand A, Beaudeux JL. Metformin reduces angiotensin-mediated intracellular production of reactive oxygen species in endothelial cells through the inhibition of protein kinase C. Biochem Pharmacol 2006; 72:176-83. [PMID: 16730666 DOI: 10.1016/j.bcp.2006.04.027] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Revised: 04/27/2006] [Accepted: 04/27/2006] [Indexed: 11/15/2022]
Abstract
Oxidative stress plays a major role in the pathogenesis and in the onset of macrovascular complications of diabetes. We previously reported that the antihyperglycaemic drug metformin was able to decrease significantly intracellular reactive oxygen species (ROS) production of bovine aortic endothelial cells (BAEC) activated by high levels of glucose and angiotensin II (ANG). The aim of the present study was to investigate whether the antioxidant effect of metformin on BAEC could be mediated through a modulation of protein kinase C (PKC) activity, which plays a key role in the pathophysiology of diabetes. The effects of metformin on intracellular ROS production, PKC translocation and activity were studied on endothelial cells stimulated by PMA (a direct PKC activator), ANG or high levels of glucose as pathophysiological stimuli of endothelial dysfunction in diabetes. We showed that metformin decreased ROS production on PMA-, ANG- and glucose-stimulated BAEC in a similar manner to that obtained by PKC specific inhibitors (calphostin C, chelerythrine) alone. On the other hand, metformin reduced both PKC membrane translocation and kinase activity in ANG-stimulated cells. In PMA-activated cells, metformin reduced membrane PKC activity but we did not observe any alteration of PKC membrane translocation. Finally, in vitro incubation with purified PKC indicated that metformin had no direct effect on PKC activity. Taken together, our results suggest that metformin exerted intracellular antioxidant properties by decreasing ROS production through the inhibition of PKC activity.
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Affiliation(s)
- M Mahrouf
- EA 3617 Stress Oxydant et Atteintes Vasculaires, Département de Biochimie, Faculté de Pharmacie, 4, Avenue de l'Observatoire, F75006 Paris, France
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