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Ji L, Su S, Xin M, Zhang Z, Nan X, Li Z, Lu D. Luteolin ameliorates hypoxia-induced pulmonary hypertension via regulating HIF-2α-Arg-NO axis and PI3K-AKT-eNOS-NO signaling pathway. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2022; 104:154329. [PMID: 35843187 DOI: 10.1016/j.phymed.2022.154329] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 06/23/2022] [Accepted: 07/07/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Pulmonary hypertension (PH) is a devastating disease with poor prognosis and high mortality. Hypoxia induced pulmonary hypertension (HPH) is a persistent threat to human health, especially to people who live on high altitude plateau. Pulmonary vascular endothelial cell is involved in numerous pathophysiological processes, including in vasoconstriction, oxidative stress, cell growth and differentiation. Endothelial cells (ECs) are the first layer to be exposed to changed oxygen levels and hypoxia could lead to ECs dysfunction. Endothelial-derived nitric oxide (NO) is the most important bioactive molecule, which could regulate endothelial homeostasis. PH pathophysiology has been linked to the disruption of NO pathways. PURPOSE Luteolin is a kind of plant active ingredient with multiple pharmacological activities. The purpose of this study is to detect the effect of luteolin on HPH with in vivo, ex vivo and in vitro analyses and to further elucidate luteolin's pharmaceutical mechanism with NO related signaling pathway regulation. METHODS Hypobaric chamber was used to establish HPH animal model. Rats were intragastrically administrated luteolin for 28 days. Then hemodynamic indexes, histopathological changes, pulmonary artery endothelial function, NO content and arginase activity in lung tissue, NO related pathway proteins expression were measured to evaluate the effect of luteolin on HPH. PAECs were treated with 1% O2 and incubated with or without luteolin. PAECs vitality, NO content in cells supernatant, and NO related pathway proteins expression were tested to reveal the protective mechanism of luteolin. RESULTS Luteolin decreased mean pulmonary hypertension of HPH rats, alleviated right ventricular and pulmonary vascular remodeling. Immunofluorescence staining (vWF), isolated perfused/ventilated rat lung experiment indicated that luteolin protected pulmonary vascular endothelial function of HPH rats. Luteolin increased NO content in PAECs supernatant while decreased NO level in lung tissues of HPH rats. Further, it was demonstrated that luteolin inhibited HIF-2α-Arg axis in PAECs and HPH rats. PI3K-AKT-eNOS signaling pathway was upregulated in PAECs, but which was downregulated in lung tissues of HPH rats. Pharmacological effect of luteolin was equivalent or better than sildenafil. CONCLUSION Luteolin ameliorated HPH in rats by protecting pulmonary vascular endothelial function via regulating HIF-2α-Arg-NO axis and PI3K-AKT-eNOS-NO signaling pathway. This study may provide a novel perspective and approach to alleviate the devastating disease of HPH.
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Affiliation(s)
- Lei Ji
- Research Center for High Altitude Medicine, Key Laboratory of High Altitude Medicine (Ministry of Education), Key Laboratory of Application and Foundation for High Altitude Medicine Research in Qinghai Province (Qinghai-Utah Joint Research Key Lab for High Altitude Medicine), Qinghai University, Xining, China; Qinghai Provincial People's Hospital, Xining, China
| | - Shanshan Su
- Technical Center of Xining Customs, Key Laboratory of Food Safety Research in Qinghai Province, Xining, China
| | - Mingyuan Xin
- Medical College, Qinghai University, Xining, China
| | - Zhaoxia Zhang
- Research Center for High Altitude Medicine, Key Laboratory of High Altitude Medicine (Ministry of Education), Key Laboratory of Application and Foundation for High Altitude Medicine Research in Qinghai Province (Qinghai-Utah Joint Research Key Lab for High Altitude Medicine), Qinghai University, Xining, China
| | - Xingmei Nan
- Medical College, Qinghai University, Xining, China
| | - Zhanqiang Li
- Research Center for High Altitude Medicine, Key Laboratory of High Altitude Medicine (Ministry of Education), Key Laboratory of Application and Foundation for High Altitude Medicine Research in Qinghai Province (Qinghai-Utah Joint Research Key Lab for High Altitude Medicine), Qinghai University, Xining, China.
| | - Dianxiang Lu
- Research Center for High Altitude Medicine, Key Laboratory of High Altitude Medicine (Ministry of Education), Key Laboratory of Application and Foundation for High Altitude Medicine Research in Qinghai Province (Qinghai-Utah Joint Research Key Lab for High Altitude Medicine), Qinghai University, Xining, China.
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Jankovic A, Zakic T, Milicic M, Unic-Stojanovic D, Kalezic A, Korac A, Jovic M, Korac B. Effects of Remote Ischaemic Preconditioning on the Internal Thoracic Artery Nitric Oxide Synthase Isoforms in Patients Undergoing Coronary Artery Bypass Grafting. Antioxidants (Basel) 2021; 10:antiox10121910. [PMID: 34943013 PMCID: PMC8750270 DOI: 10.3390/antiox10121910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/25/2021] [Accepted: 11/26/2021] [Indexed: 01/03/2023] Open
Abstract
Remote ischaemic preconditioning (RIPC) is a medical procedure that consists of repeated brief periods of transient ischaemia and reperfusion of distant organs (limbs) with the ability to provide internal organ protection from ischaemia. Even though RIPC has been successfully applied in patients with myocardial infarction during coronary revascularization (surgery/percutaneous angioplasty), the underlying molecular mechanisms are yet to be clarified. Thus, our study aimed to determine the role of nitric oxide synthase (NOS) isoforms in RIPC-induced protection (3 × 5 min of forearm ischaemia with 5 min of reperfusion) of arterial graft in patients undergoing urgent coronary artery bypass grafting (CABG). We examined RIPC effects on specific expression and immunolocalization of three NOS isoforms — endothelial (eNOS), inducible (iNOS) and neuronal (nNOS) in patients’ internal thoracic artery (ITA) used as a graft. We found that the application of RIPC protocol leads to an increased protein expression of eNOS, which was further confirmed with strong eNOS immunopositivity, especially in the endothelium and smooth muscle cells of ITA. The same analysis of two other NOS isoforms, iNOS and nNOS, showed no significant differences between patients undergoing CABG with or without RIPC. Our results demonstrate RIPC-induced upregulation of eNOS in human ITA, pointing to its significance in achieving protective phenotype on a systemic level with important implications for graft patency.
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Affiliation(s)
- Aleksandra Jankovic
- Department of Physiology, Institute for Biological Research “Sinisa Stankovic”—National Institute of Republic of Serbia, University of Belgrade, 11000 Belgrade, Serbia; (A.J.); (T.Z.); (A.K.)
| | - Tamara Zakic
- Department of Physiology, Institute for Biological Research “Sinisa Stankovic”—National Institute of Republic of Serbia, University of Belgrade, 11000 Belgrade, Serbia; (A.J.); (T.Z.); (A.K.)
| | - Miroslav Milicic
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (M.M.); (D.U.-S.)
- Dedinje Cardiovascular Institute, 11000 Belgrade, Serbia;
| | - Dragana Unic-Stojanovic
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (M.M.); (D.U.-S.)
- Dedinje Cardiovascular Institute, 11000 Belgrade, Serbia;
| | - Andjelika Kalezic
- Department of Physiology, Institute for Biological Research “Sinisa Stankovic”—National Institute of Republic of Serbia, University of Belgrade, 11000 Belgrade, Serbia; (A.J.); (T.Z.); (A.K.)
| | - Aleksandra Korac
- Faculty of Biology, University of Belgrade, 11000 Belgrade, Serbia;
| | - Miomir Jovic
- Dedinje Cardiovascular Institute, 11000 Belgrade, Serbia;
| | - Bato Korac
- Department of Physiology, Institute for Biological Research “Sinisa Stankovic”—National Institute of Republic of Serbia, University of Belgrade, 11000 Belgrade, Serbia; (A.J.); (T.Z.); (A.K.)
- Faculty of Biology, University of Belgrade, 11000 Belgrade, Serbia;
- Correspondence: ; Tel.: +381-11-2078-307
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Janaszak-Jasiecka A, Siekierzycka A, Płoska A, Dobrucki IT, Kalinowski L. Endothelial Dysfunction Driven by Hypoxia-The Influence of Oxygen Deficiency on NO Bioavailability. Biomolecules 2021; 11:biom11070982. [PMID: 34356605 PMCID: PMC8301841 DOI: 10.3390/biom11070982] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/25/2021] [Accepted: 07/02/2021] [Indexed: 12/12/2022] Open
Abstract
Cardiovascular diseases (CVDs) are the leading cause of death worldwide. The initial stage of CVDs is characterized by endothelial dysfunction, defined as the limited bioavailability of nitric oxide (NO). Thus, any factors that interfere with the synthesis or metabolism of NO in endothelial cells are involved in CVD pathogenesis. It is well established that hypoxia is both the triggering factor as well as the accompanying factor in cardiovascular disease, and diminished tissue oxygen levels have been reported to influence endothelial NO bioavailability. In endothelial cells, NO is produced by endothelial nitric oxide synthase (eNOS) from L-Arg, with tetrahydrobiopterin (BH4) as an essential cofactor. Here, we discuss the mechanisms by which hypoxia affects NO bioavailability, including regulation of eNOS expression and activity. What is particularly important is the fact that hypoxia contributes to the depletion of cofactor BH4 and deficiency of substrate L-Arg, and thus elicits eNOS uncoupling-a state in which the enzyme produces superoxide instead of NO. eNOS uncoupling and the resulting oxidative stress is the major driver of endothelial dysfunction and atherogenesis. Moreover, hypoxia induces impairment in mitochondrial respiration and endothelial cell activation; thus, oxidative stress and inflammation, along with the hypoxic response, contribute to the development of endothelial dysfunction.
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Affiliation(s)
- Anna Janaszak-Jasiecka
- Department of Medical Laboratory Diagnostics—Fahrenheit Biobank BBMRI.pl, Medical University of Gdansk, 80-211 Gdansk, Poland; (A.J.-J.); (A.S.); (A.P.)
- Biobanking and Biomolecular Resources Research Infrastructure Poland (BBMRI.pl), 80-211 Gdansk, Poland
| | - Anna Siekierzycka
- Department of Medical Laboratory Diagnostics—Fahrenheit Biobank BBMRI.pl, Medical University of Gdansk, 80-211 Gdansk, Poland; (A.J.-J.); (A.S.); (A.P.)
- Laboratory of Trace Elements Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, 31-343 Krakow, Poland
| | - Agata Płoska
- Department of Medical Laboratory Diagnostics—Fahrenheit Biobank BBMRI.pl, Medical University of Gdansk, 80-211 Gdansk, Poland; (A.J.-J.); (A.S.); (A.P.)
- Biobanking and Biomolecular Resources Research Infrastructure Poland (BBMRI.pl), 80-211 Gdansk, Poland
| | - Iwona T. Dobrucki
- University of Illinois at Urbana-Champaign Beckman Institute for Advanced Science and Technology, 405 N Mathews Ave, MC-251, Urbana, IL 61801, USA;
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Leszek Kalinowski
- Department of Medical Laboratory Diagnostics—Fahrenheit Biobank BBMRI.pl, Medical University of Gdansk, 80-211 Gdansk, Poland; (A.J.-J.); (A.S.); (A.P.)
- Biobanking and Biomolecular Resources Research Infrastructure Poland (BBMRI.pl), 80-211 Gdansk, Poland
- BioTechMed Centre, Department of Mechanics of Materials and Structures, Gdansk University of Technology, 80-233 Gdansk, Poland
- Correspondence:
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Roberts J, Pritchard AL, Treweeke AT, Rossi AG, Brace N, Cahill P, MacRury SM, Wei J, Megson IL. Why Is COVID-19 More Severe in Patients With Diabetes? The Role of Angiotensin-Converting Enzyme 2, Endothelial Dysfunction and the Immunoinflammatory System. Front Cardiovasc Med 2021; 7:629933. [PMID: 33614744 PMCID: PMC7886785 DOI: 10.3389/fcvm.2020.629933] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 12/15/2020] [Indexed: 01/08/2023] Open
Abstract
Meta-analyses have indicated that individuals with type 1 or type 2 diabetes are at increased risk of suffering a severe form of COVID-19 and have a higher mortality rate than the non-diabetic population. Patients with diabetes have chronic, low-level systemic inflammation, which results in global cellular dysfunction underlying the wide variety of symptoms associated with the disease, including an increased risk of respiratory infection. While the increased severity of COVID-19 amongst patients with diabetes is not yet fully understood, the common features associated with both diseases are dysregulated immune and inflammatory responses. An additional key player in COVID-19 is the enzyme, angiotensin-converting enzyme 2 (ACE2), which is essential for adhesion and uptake of virus into cells prior to replication. Changes to the expression of ACE2 in diabetes have been documented, but they vary across different organs and the importance of such changes on COVID-19 severity are still under investigation. This review will examine and summarise existing data on how immune and inflammatory processes interplay with the pathogenesis of COVID-19, with a particular focus on the impacts that diabetes, endothelial dysfunction and the expression dynamics of ACE2 have on the disease severity.
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Affiliation(s)
- Jacob Roberts
- Institute for Health Research and Innovation, University of the Highlands and Islands, Inverness, United Kingdom
| | - Antonia L. Pritchard
- Institute for Health Research and Innovation, University of the Highlands and Islands, Inverness, United Kingdom
| | - Andrew T. Treweeke
- Institute for Health Research and Innovation, University of the Highlands and Islands, Inverness, United Kingdom
| | - Adriano G. Rossi
- Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Nicole Brace
- Institute for Health Research and Innovation, University of the Highlands and Islands, Inverness, United Kingdom
| | - Paul Cahill
- School of Biotechnology, Dublin City University, Dublin, Ireland
| | - Sandra M. MacRury
- Institute for Health Research and Innovation, University of the Highlands and Islands, Inverness, United Kingdom
| | - Jun Wei
- Institute for Health Research and Innovation, University of the Highlands and Islands, Inverness, United Kingdom
| | - Ian L. Megson
- Institute for Health Research and Innovation, University of the Highlands and Islands, Inverness, United Kingdom
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Sharma M, Singh K, Himashree G, Bhaumik G, Kumar B, Sethy NK. Estrogen receptor (ESR1 and ESR2)-mediated activation of eNOS-NO-cGMP pathway facilitates high altitude acclimatization. Nitric Oxide 2020; 102:12-20. [PMID: 32544536 DOI: 10.1016/j.niox.2020.05.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 05/23/2020] [Accepted: 05/26/2020] [Indexed: 02/01/2023]
Abstract
Higher levels of circulatory nitric oxide (NO) and NO metabolites reportedly facilitate high altitude acclimatization. But the underlying factors and molecular pathways promoting NO production at high altitude has been poorly characterized. Studying healthy lowlanders at sea level (C, lowlander) and high altitude (3500 m, after day 1, 4 and 7 of ascent), we report higher protein levels of eNOS and eNOSSer1177, higher plasma levels of BH4, NOx (nitrate and nitrites), cGMP and lower levels of endogenous eNOS inhibitor ADMA during healthy high altitude acclimatization. Our qRT-PCR-based gene expression studies identified higher levels of eNOS/NOS3 mRNA along with several other eNOS pathway genes like CALM1, SLC7A1 and DNM2. In addition, we observed higher mRNA levels of estrogen (E2) receptors ERα/ESR1 and ERβ/ESR2 at high altitude that transcriptionally activates NOS3. We also observed higher mRNA level of membrane receptor ERBB2 that phosphorylates eNOS at Ser1177 and thus augments NO availability. Evaluating E2 biosynthesis at high altitude, we report higher plasma levels of CYP11A1, CYP19A1, E2, lower levels of testosterone (T) and T/E2 ratio as compared to sea level. Correlation studies revealed moderate positive correlation between E2 and NOx (R = 0.68, p = 0.02) after day 4 and cGMP (R = 0.69, p = 0.02) after day 7 at high altitude. These findings suggest a causative role of E2 and its receptors ESR1 and ESR2 in augmenting eNOS activity and NO availability during healthy high altitude ascent. These results will aid in better understanding of NO production during hypobaric hypoxia and help in designing better high altitude acclimatization protocols.
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Affiliation(s)
- Manish Sharma
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organisation, Lucknow Road, Timarpur, Delhi, 110054, India
| | - Krishan Singh
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organisation, Lucknow Road, Timarpur, Delhi, 110054, India; High Altitude Medical Research Centre (HAMRC), C/o 56 APO, Leh-Ladakh, 901205, India
| | - Gidugu Himashree
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organisation, Lucknow Road, Timarpur, Delhi, 110054, India; Military Hospital, Nasirabad, Rajasthan, 305601, India
| | - Gopinath Bhaumik
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organisation, Lucknow Road, Timarpur, Delhi, 110054, India
| | - Bhuvnesh Kumar
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organisation, Lucknow Road, Timarpur, Delhi, 110054, India
| | - Niroj Kumar Sethy
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organisation, Lucknow Road, Timarpur, Delhi, 110054, India.
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McElwain CJ, Tuboly E, McCarthy FP, McCarthy CM. Mechanisms of Endothelial Dysfunction in Pre-eclampsia and Gestational Diabetes Mellitus: Windows Into Future Cardiometabolic Health? Front Endocrinol (Lausanne) 2020; 11:655. [PMID: 33042016 PMCID: PMC7516342 DOI: 10.3389/fendo.2020.00655] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 08/11/2020] [Indexed: 12/12/2022] Open
Abstract
Placental insufficiency and adipose tissue dysregulation are postulated to play key roles in the pathophysiology of both pre-eclampsia (PE) and gestational diabetes mellitus (GDM). A dysfunctional release of deleterious signaling motifs can offset an increase in circulating oxidative stressors, pro-inflammatory factors and various cytokines. It has been previously postulated that endothelial dysfunction, instigated by signaling from endocrine organs such as the placenta and adipose tissue, may be a key mediator of the vasculopathy that is evident in both adverse obstetric complications. These signaling pathways also have significant effects on long term maternal cardiometabolic health outcomes, specifically cardiovascular disease, hypertension, and type II diabetes. Recent studies have noted that both PE and GDM are strongly associated with lower maternal flow-mediated dilation, however the exact pathways which link endothelial dysfunction to clinical outcomes in these complications remains in question. The current diagnostic regimen for both PE and GDM lacks specificity and consistency in relation to clinical guidelines. Furthermore, current therapeutic options rely largely on clinical symptom control such as antihypertensives and insulin therapy, rather than that of early intervention or prophylaxis. A better understanding of the pathogenic origin of these obstetric complications will allow for more targeted therapeutic interventions. In this review we will explore the complex signaling relationship between the placenta and adipose tissue in PE and GDM and investigate how these intricate pathways affect maternal endothelial function and, hence, play a role in acute pathophysiology and the development of future chronic maternal health outcomes.
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Affiliation(s)
- Colm J. McElwain
- Department of Pharmacology and Therapeutics, Western Gateway Building, University College Cork, Cork, Ireland
- *Correspondence: Colm J. McElwain
| | - Eszter Tuboly
- Department of Pharmacology and Therapeutics, Western Gateway Building, University College Cork, Cork, Ireland
| | - Fergus P. McCarthy
- Department of Obstetrics and Gynaecology, Cork University Maternity Hospital, Cork, Ireland
| | - Cathal M. McCarthy
- Department of Pharmacology and Therapeutics, Western Gateway Building, University College Cork, Cork, Ireland
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Park JH, Park KA, Cha J, Kim ST, Chung CS, Lee MJ. A case report of isolated orbital vasculitis mimicking retinal migraine: A potential cause of recurrent transient monocular blindness and ipsilateral headache. Cephalalgia 2018; 39:792-798. [PMID: 30099954 DOI: 10.1177/0333102418794482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Retinal migraine is an important differential diagnosis of recurrent transient monocular blindness accompanied by headache when other etiologies are excluded. Here, we report a case of orbital vasculitis which initially mimicked retinal migraine. CASE REPORT A 47-year-old woman had recurrent episodes of fully reversible transient monocular blindness accompanied by ipsilateral headache for 15 months. The patient's neuroimaging and cardiac and ophthalmologic evaluations were normal. With a diagnosis of retinal migraine, her symptoms remitted in response to prophylactic treatment with topiramate and propranolol for 8 months. Three months after discontinuation of medications, transient monocular blindness recurred. High-resolution vessel wall magnetic resonance imaging revealed enhancement of the ipsilateral orbital vessels. Isolated orbital vasculitis was diagnosed. Complete remission of transient monocular blindness was achieved after steroid pulse therapy. DISCUSSION Isolated orbital vasculitis should be considered in differential diagnosis of recurrent transient monocular blindness and ipsilateral headache. High-resolution vessel wall magnetic resonance imaging can be helpful for the diagnosis.
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Affiliation(s)
- Ji-Hyung Park
- 1 Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Kyung-Ah Park
- 2 Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jihoon Cha
- 3 Department of Radiology, Severance Hospital, Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea
| | - Sung Tae Kim
- 4 Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Chin-Sang Chung
- 1 Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.,5 Neuroscience Center, Samsung Medical Center, Seoul, Korea
| | - Mi Ji Lee
- 1 Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.,5 Neuroscience Center, Samsung Medical Center, Seoul, Korea
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Yoon G, Oh CS, Kim HS. Distinctive expression patterns of hypoxia-inducible factor-1α and endothelial nitric oxide synthase following hypergravity exposure. Oncotarget 2018; 7:33675-88. [PMID: 27191892 PMCID: PMC5085111 DOI: 10.18632/oncotarget.9372] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 05/05/2016] [Indexed: 01/13/2023] Open
Abstract
This study was designed to examine the expression of hypoxia-inducible factor-1α (HIF-1α) and the level and activity of endothelial nitric oxide synthase (eNOS) in the hearts and livers of mice exposed to hypergravity. Hypergravity-induced hypoxia and the subsequent post-exposure reoxygenation significantly increased cardiac HIF-1α levels. Furthermore, the levels and activity of cardiac eNOS also showed significant increase immediately following hypergravity exposure and during the reoxygenation period. In contrast, the expression of phosphorylated Akt (p-Akt) and phosphorylated extracellular signal-regulated kinase (p-ERK) showed significant elevation only during the reoxygenation period. These data raise the possibility that the increase in cardiac HIF-1α expression induced by reoxygenation involves a cascade of signaling events, including activation of the Akt and ERK pathways. In the liver, HIF-1α expression was significantly increased immediately after hypergravity exposure, indicating that hypergravity exposure to causes hepatocellular hypoxia. The hypergravity-exposed livers showed significantly higher eNOS immunoreactivity than did those of control mice. Consistent with these results, significant increases in eNOS activity and nitrate/nitrite levels were also observed. These findings suggest that hypergravity-induced hypoxia plays a significant role in the upregulation of hepatic eNOS.
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Affiliation(s)
- Gun Yoon
- Department of Obstetrics and Gynecology, Pusan National University Yangsan Hospital, Pusan National University School of Medicine, Yangsan-si, Gyeongsangnam-do, Republic of Korea
| | - Choong Sik Oh
- Aerospace Medicine Research Center, Republic of Korea Air Force Aerospace Medical Center, Cheongju-si, Chungcheongbuk-do, Republic of Korea
| | - Hyun-Soo Kim
- Department of Pathology, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea
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Lucas ML, Carraro CC, Belló-Klein A, Kalil AN, Aerts N. Oxidative Stress in Human Aorta of Patients with Advanced Aortoiliac Occlusive Disease. Braz J Cardiovasc Surg 2017; 31:428-433. [PMID: 28076619 PMCID: PMC5407147 DOI: 10.5935/1678-9741.20160086] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 09/30/2016] [Indexed: 01/21/2023] Open
Abstract
Introduction Oxidative stress seems to be a role in the atherosclerosis process, but research in human beings is scarce. Objective To evaluate the role of oxidative stress on human aortas of patients submitted to surgical treatment for advanced aortoiliac occlusive disease. Methods Twenty-six patients were divided into three groups: control group (n=10) formed by cadaveric organ donors; severe aortoiliac stenosis group (patients with severe aortoiliac stenosis; n=9); and total aortoiliac occlusion group (patients with chronic total aortoiliac occlusion; n=7). We evaluated the reactive oxygen species concentration, nicotinamide adenine dinucleotide phosphate-oxidase, superoxide dismutase and catalase activities as well as nitrite levels in samples of aortas harvested during aortofemoral bypass for treatment of advanced aortoiliac occlusive disease. Results We observed a higher level of reactive oxygen species in total aortoiliac occlusion group (48.3±9.56 pmol/mg protein) when compared to severe aortoiliac stenosis (33.5±7.4 pmol/mg protein) and control (4.91±0.8 pmol/mg protein) groups (P<0.05). Nicotinamide adenine dinucleotide phosphate oxidase activity was also higher in total aortoiliac occlusion group when compared to the control group (3.81±1.7 versus 1.05±0.31 µmol/min.mg protein; P<0.05). Furthermore, superoxide dismutase and catalase activities were significantly higher in the severe aortoiliac stenosis and total aortoiliac occlusion groups when compared to the control cases (P<0.05). Nitrite concentration was smaller in the severe aortoiliac stenosis group in comparing to the other groups. Conclusion Our results indicated an increase of reactive oxygen species levels and nicotinamide adenine dinucleotide phosphate-oxidase activity in human aortic samples of patients with advanced aortoiliac occlusive disease. The increase of antioxidant enzymes activities may be due to a compensative phenomenon to reactive oxygen species production mediated by nicotinamide adenine dinucleotide phosphate oxidase. This preliminary study offers us a more comprehensive knowledge about the role of oxidative stress in advanced aortoiliac occlusive disease in human beings.
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Affiliation(s)
| | | | | | | | - Newton Aerts
- Universidade Federal de Ciências da Saúde (UFCSPA), Porto Alegre, RS, Brazil
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de Groot M, Schuurs TA, Keizer PPM, Fekken S, Leuvenink HGD, Van Schilfgaarde R. Response of Encapsulated Rat Pancreatic Islets to Hypoxia. Cell Transplant 2017; 12:867-875. [PMID: 28863739 DOI: 10.3727/000000003771000219] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Hypoxia contributes to encapsulated pancreatic islet graft failure. To gain insight into the mechanisms that lead to hypoxia-induced graft failure, encapsulated islet function, vitality, and cell replication were assessed after 2 and 5 days of hypoxic (1% O2) and normoxic (20% O2) culture. The mRNA expression levels of Bcl-2, Bax, inducible nitric oxide synthase (iNOS), and monocyte chemoattractant protein 1 (MCP-1) were assessed, as well as the amount of nitrite and MCP-1 in the culture medium. Hypoxia was associated with loss of encapsulated islet function and vitality, but not with an increase in islet cell replication. Loss of vitality was due to necrosis, and only modestly due to apoptosis. Hypoxia was not associated with changes in the Bcl-2/Bax mRNA ratio, but it did increase the expression of iNOS and MCP-1 mRNA. The increased mRNA levels were, however, not associated with elevated concentrations of nitrite nor with elevated levels of MCP-1 protein. The increased iNOS mRNA levels imply a role for NO in the completion of cell death by hypoxia. The increased MCP-1 mRNA levels suggest that encapsulated islets in vivo contribute to their own graft failure by attracting cytokine-producing macrophages. The discrepancy between iNOS mRNA and nitrite is explained by the longer half-life of NO during hypoxia. MCP-1 protein levels are underestimated as a consequence of the lower number of vital cells in combination with a higher proteolytic activity due to necrosis. Thus, strategies to eliminate hypoxia may not only improve islet function and vitality, but may also reduce the attraction of macrophages by encapsulated islets.
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Affiliation(s)
- M de Groot
- Surgical Research Laboratory, Department of Surgery, Groningen University Hospital, Groningen, The Netherlands
| | - T A Schuurs
- Surgical Research Laboratory, Department of Surgery, Groningen University Hospital, Groningen, The Netherlands
| | - P P M Keizer
- Surgical Research Laboratory, Department of Surgery, Groningen University Hospital, Groningen, The Netherlands
| | - S Fekken
- Surgical Research Laboratory, Department of Surgery, Groningen University Hospital, Groningen, The Netherlands
| | - H G D Leuvenink
- Surgical Research Laboratory, Department of Surgery, Groningen University Hospital, Groningen, The Netherlands
| | - R Van Schilfgaarde
- Surgical Research Laboratory, Department of Surgery, Groningen University Hospital, Groningen, The Netherlands
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Manukhina EB, Downey HF, Mallet RT. Role of Nitric Oxide in Cardiovascular Adaptation to Intermittent Hypoxia. Exp Biol Med (Maywood) 2016; 231:343-65. [PMID: 16565431 DOI: 10.1177/153537020623100401] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Hypoxia is one of the most frequently encountered stresses in health and disease. The duration, frequency, and severity of hypoxic episodes are critical factors determining whether hypoxia is beneficial or harmful. Adaptation to intermittent hypoxia has been demonstrated to confer cardiovascular protection against more severe and sustained hypoxia, and, moreover, to protect against other stresses, including ischemia. Thus, the direct and cross protective effects of adaptation to intermittent hypoxia have been used for treatment and prevention of a variety of diseases and to increase efficiency of exercise training. Evidence is mounting that nitric oxide (NO) plays a central role in these adaptive mechanisms. NO-dependent protective mechanisms activated by intermittent hypoxia include stimulation of NO synthesis as well as restriction of NO overproduction. In addition, alternative, nonenzymic sources of NO and negative feedback of NO synthesis are important factors in optimizing NO concentrations. The adaptive enhancement of NO synthesis and/or availability activates or increases expression of other protective factors, including heat shock proteins, antioxidants and prostaglandins, making the protection more robust and sustained. Understanding the role of NO in mechanisms of adaptation to hypoxia will support development of therapies to prevent and treat hypoxic or ischemic damage to organs and cells and to increase adaptive capabilities of the organism.
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Kalinowski L, Janaszak-Jasiecka A, Siekierzycka A, Bartoszewska S, Woźniak M, Lejnowski D, Collawn JF, Bartoszewski R. Posttranscriptional and transcriptional regulation of endothelial nitric-oxide synthase during hypoxia: the role of microRNAs. Cell Mol Biol Lett 2016; 21:16. [PMID: 28536619 PMCID: PMC5415778 DOI: 10.1186/s11658-016-0017-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 08/18/2016] [Indexed: 02/07/2023] Open
Abstract
Understanding the cellular pathways that regulate endothelial nitric oxide (eNOS, NOS3) expression and consequently nitric oxide (NO) bioavailability during hypoxia is a necessary aspect in the development of novel treatments for cardiovascular disorders. eNOS expression and eNOS-dependent NO cellular signaling during hypoxia promote an equilibrium of transcriptional and posttranscriptional molecular mechanisms that belong to both proapoptotic and survival pathways. Furthermore, NO bioavailability results not only from eNOS levels, but also relies on the presence of eNOS substrate and cofactors, the phosphorylation status of eNOS, and the presence of reactive oxygen species (ROS) that can inactivate eNOS. Since both NOS3 levels and these signaling pathways can also be a subject of posttranscriptional modulation by microRNAs (miRNAs), this class of short noncoding RNAs contribute another level of regulation for NO bioavailability. As miRNA antagomirs or specific target protectors could be used in therapeutic approaches to regulate NO levels, either by changing NOS3 mRNA stability or through factors governing eNOS activity, it is critical to understand their role in governing eNOS activity during hypoxa. In contrast to a large number of miRNAs reported to the change eNOS expression during hypoxia, only a few miRNAs modulate eNOS activity. Furthermore, impaired miRNA biogenesis leads to NOS3 mRNA stabilization under hypoxia. Here we discuss the recent studies that define miRNAs’ role in maintaining endothelial NO bioavailability emphasizing those miRNAs that directly modulate NOS3 expression or eNOS activity.
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Affiliation(s)
- Leszek Kalinowski
- Department of Medical Laboratory Diagnostics and Central Bank of Frozen Tissues & Genetic Specimens, Medical University of Gdansk, Debinki 7, 80-211 Gdansk, Poland
| | - Anna Janaszak-Jasiecka
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Hallera 107, 80-416 Gdansk, Poland
| | - Anna Siekierzycka
- Department of Medical Laboratory Diagnostics and Central Bank of Frozen Tissues & Genetic Specimens, Medical University of Gdansk, Debinki 7, 80-211 Gdansk, Poland
| | - Sylwia Bartoszewska
- Department of Inorganic Chemistry, Medical University of Gdansk, Gdansk, Poland
| | - Marcin Woźniak
- Department of Medical Laboratory Diagnostics and Central Bank of Frozen Tissues & Genetic Specimens, Medical University of Gdansk, Debinki 7, 80-211 Gdansk, Poland
| | - Dawid Lejnowski
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Hallera 107, 80-416 Gdansk, Poland
| | - James F Collawn
- Department of Cell Biology, Developmental, and Integrative, University of Alabama at Birmingham, Birmingham, USA
| | - Rafal Bartoszewski
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Hallera 107, 80-416 Gdansk, Poland
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Dong Y, Thompson LP. Differential Expression of Endothelial Nitric Oxide Synthase in Coronary and Cardiac Tissue in Hypoxic Fetal Guinea Pig Hearts. ACTA ACUST UNITED AC 2016; 13:483-90. [PMID: 16979353 DOI: 10.1016/j.jsgi.2006.06.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2005] [Indexed: 11/23/2022]
Abstract
OBJECTIVE The purpose of the present study was to quantify the effect of chronic hypoxia on endothelial nitric oxide synthase (eNOS) gene and protein expression of fetal coronary artery segments and cardiac tissue of fetal guinea pig hearts. METHODS Time-mated pregnant guinea pigs (term = 65 days) were housed in room air (NMX, n = 6) or in a hypoxic chamber containing 10.5% O2 for 14 days (HPX14, n = 6). At near term (60 days gestation), fetuses were excised from anesthetized animals via hysterotomy and hearts were removed and weighed. Both coronary artery segments and cardiac ventricle were excised from the same hearts, frozen, and stored at -80 C until ready for study. eNOS mRNA was quantified using real-time polymerase chain reaction (PCR) based on SYBR Green I labeling (BioRad Laboratories, Hercules, CA) using eNOS primers obtained from GeneBank normalized to 18S. eNOS proteins were quantified by Western immunoblotting using eNOS antibody (1:200) and normalized to normoxic controls. eNOS cell-specific localization in the fetal guinea pig heart was performed by double immunofluorescence staining. RESULTS Both coronary artery endothelial cells (EC) and cardiomyocytes (CM) but not vascular smooth muscle cells of normoxic hearts exhibited positive immunostaining of eNOS protein. Chronic hypoxia significantly (P < .05) increased both eNOS mRNA and protein levels of coronary artery segments (by 210.6% and 51.4%, respectively) but decreased (P < .05) mRNA and protein of cardiac tissue (by 50.0% and 40.6%, respectively) in the same hearts. CONCLUSIONS Chronic fetal hypoxia, after 14 days, induces sustained changes in eNOS gene and eNOS protein expression that differ between coronary and cardiac tissue in the fetal guinea pig heart. This study suggests that while the functional roles of altered eNOS expression in hypoxic fetal hearts remain unclear, the site at which eNOS expression is altered may be important in the adaptive response of the fetal heart to hypoxia.
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Affiliation(s)
- Yafeng Dong
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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Thompson LP, Aguan K, Zhou H. Chronic Hypoxia Inhibits Contraction of Fetal Arteries by Increased Endothelium-Derived Nitric Oxide and Prostaglandin Synthesis. ACTA ACUST UNITED AC 2016; 11:511-20. [PMID: 15582495 DOI: 10.1016/j.jsgi.2004.05.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Chronic hypoxia causes redistribution of fetal cardiac output by mechanisms poorly understood. We tested the hypothesis that chronic hypoxia alters vascular reactivity of arteries from near-term fetal guinea pigs. METHODS Pregnant guinea pigs (50 days, term = 65 days) were exposed to either normoxia (room air) or hypoxia (12% O2) for 14 days. Carotid artery ring segments from anesthetized fetuses were mounted onto myographs for measurement of force. Contractile responses to cumulative addition of prostaglandin F2alpha (PGF2alpha, 10(-9) M to 10(-5) M), U46619, a thromboxane mimetic (10(-12) M to 12(-6) M), and KCl (10 to 120 mM) were measured in the presence and absence of INDO (INDO, 10(-5) M) alone and INDO plus nitro-L-arginine (LNA, 10(-4) M), or INDO plus N6-iminoethyl-L-lysine (LNIL, 5 x 10(-5) M, a selective iNOS inhibitor), and measured in endothelium-intact and denuded arteries. Nitric oxide synthase (NOS) activity was measured in isolated arteries by 14C-L-arginine to 14C-L-citrulline conversion. RESULTS Hypoxia decreased contractile responses to both PGF2alpha and U46619 under control conditions. Maximal contraction to both agonists was increased in hypoxemic arteries after INDO alone and INDO + LNA compared to normoxic controls. Endothelium-denudation abolished the differences between the groups. KCl contraction was unaffected by hypoxia. LNIL potentiated maximal PGF(2alpha) contraction but was similar between groups. Hypoxia increased (P < .05) total and Ca(2+)-dependent NOS activities by 1.7- and 2.1-fold, respectively, but had no effect on Ca(2+)-independent activity. CONCLUSION Chronic hypoxia alters vascular reactivity of fetal carotid arteries by increasing the contribution of both vasodilator prostaglandins and nitric oxide and suggests that changes in local vascular mechanisms may be altered by chronic hypoxia.
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Affiliation(s)
- Loren P Thompson
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
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Chalupsky K, Kračun D, Kanchev I, Bertram K, Görlach A. Folic Acid Promotes Recycling of Tetrahydrobiopterin and Protects Against Hypoxia-Induced Pulmonary Hypertension by Recoupling Endothelial Nitric Oxide Synthase. Antioxid Redox Signal 2015; 23:1076-91. [PMID: 26414244 PMCID: PMC4657514 DOI: 10.1089/ars.2015.6329] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 09/21/2015] [Accepted: 09/21/2015] [Indexed: 01/29/2023]
Abstract
AIMS Nitric oxide (NO) derived from endothelial NO synthase (eNOS) has been implicated in the adaptive response to hypoxia. An imbalance between 5,6,7,8-tetrahydrobiopterin (BH4) and 7,8-dihydrobiopterin (BH2) can result in eNOS uncoupling and the generation of superoxide instead of NO. Dihydrofolate reductase (DHFR) can recycle BH2 to BH4, leading to eNOS recoupling. However, the role of DHFR and eNOS recoupling in the response to hypoxia is not well understood. We hypothesized that increasing the capacity to recycle BH4 from BH2 would improve NO bioavailability as well as pulmonary vascular remodeling (PVR) and right ventricular hypertrophy (RVH) as indicators of pulmonary hypertension (PH) under hypoxic conditions. RESULTS In human pulmonary artery endothelial cells and murine pulmonary arteries exposed to hypoxia, eNOS was uncoupled as indicated by reduced superoxide production in the presence of the nitric oxide synthase inhibitor, L-(G)-nitro-L-arginine methyl ester (L-NAME). Concomitantly, NO levels, BH4 availability, and expression of DHFR were diminished under hypoxia. Application of folic acid (FA) restored DHFR levels, NO bioavailability, and BH4 levels under hypoxia. Importantly, FA prevented the development of hypoxia-induced PVR, right ventricular pressure increase, and RVH. INNOVATION FA-induced upregulation of DHFR recouples eNOS under hypoxia by improving BH4 recycling, thus preventing hypoxia-induced PH. CONCLUSION FA might serve as a novel therapeutic option combating PH.
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Affiliation(s)
- Karel Chalupsky
- Experimental and Molecular Pediatric Cardiology, German Heart Center Munich at the Technical University Munich, Munich, Germany
| | - Damir Kračun
- Experimental and Molecular Pediatric Cardiology, German Heart Center Munich at the Technical University Munich, Munich, Germany
| | - Ivan Kanchev
- Experimental and Molecular Pediatric Cardiology, German Heart Center Munich at the Technical University Munich, Munich, Germany
| | - Katharina Bertram
- Experimental and Molecular Pediatric Cardiology, German Heart Center Munich at the Technical University Munich, Munich, Germany
| | - Agnes Görlach
- Experimental and Molecular Pediatric Cardiology, German Heart Center Munich at the Technical University Munich, Munich, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich, Germany
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Nitric Oxide Bioavailability in Obstructive Sleep Apnea: Interplay of Asymmetric Dimethylarginine and Free Radicals. SLEEP DISORDERS 2015; 2015:387801. [PMID: 26064689 PMCID: PMC4438195 DOI: 10.1155/2015/387801] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 04/15/2015] [Accepted: 04/17/2015] [Indexed: 01/13/2023]
Abstract
Obstructive sleep apnea (OSA) occurs in 2% of middle-aged women and 4% of middle-aged men and is considered an independent risk factor for cerebrovascular and cardiovascular diseases. Nitric oxide (NO) is an important endothelium derived vasodilating substance that plays a critical role in maintaining vascular homeostasis. Low levels of NO are associated with impaired endothelial function. Asymmetric dimethylarginine (ADMA), an analogue of L-arginine, is a naturally occurring product of metabolism found in the human circulation. Elevated levels of ADMA inhibit NO synthesis while oxidative stress decreases its bioavailability, so impairing endothelial function and promoting atherosclerosis. Several clinical trials report increased oxidative stress and ADMA levels in patients with OSA. This review discusses the role of oxidative stress and increased ADMA levels in cardiovascular disease resulting from OSA.
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Varadharaj S, Porter K, Pleister A, Wannemacher J, Sow A, Jarjoura D, Zweier JL, Khayat RN. Endothelial nitric oxide synthase uncoupling: a novel pathway in OSA induced vascular endothelial dysfunction. Respir Physiol Neurobiol 2015; 207:40-7. [PMID: 25534145 PMCID: PMC4297730 DOI: 10.1016/j.resp.2014.12.012] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 12/04/2014] [Accepted: 12/15/2014] [Indexed: 01/22/2023]
Abstract
The mechanism of vascular endothelial dysfunction (VED) and cardiovascular disease in obstructive sleep apnea (OSA) is unknown. We performed a comprehensive evaluation of endothelial nitric oxide synthase (eNOS) function directly in the microcirculatory endothelial tissue of OSA patients who have very low cardiovascular risk status. Nineteen OSA patients underwent gluteal biopsies before, and after effective treatment of OSA. We measured superoxide (O2(•-)) and nitric oxide (NO) in the microcirculatory endothelium using confocal microscopy. We evaluated the effect of the NOS inhibitor l-Nitroarginine-Methyl-Ester (l-NAME) and the NOS cofactor tetrahydrobiopterin (BH4) on endothelial O2(•-) and NO in patient endothelial tissue before and after treatment. We found that eNOS is dysfunctional in OSA patients pre-treatment, and is a source of endothelial O2(•-) overproduction. eNOS dysfunction was reversible with the addition of BH4. These findings provide a new mechanism of endothelial dysfunction in OSA patients and a potentially targetable pathway for treatment of cardiovascular risk in OSA.
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Affiliation(s)
- Saradhadevi Varadharaj
- The Sleep Heart Program, the Ohio State University, Columbus, OH, United States; Division of Pulmonary Critical Care and Sleep, The Davis Heart and Lung Research Institute and Division of Cardiovascular Medicine, the Ohio State University, Columbus, OH, United States
| | - Kyle Porter
- The Center for Biostatistics, the Ohio State University, Columbus, OH, United States
| | - Adam Pleister
- The Sleep Heart Program, the Ohio State University, Columbus, OH, United States
| | - Jacob Wannemacher
- The Sleep Heart Program, the Ohio State University, Columbus, OH, United States
| | - Angela Sow
- The Sleep Heart Program, the Ohio State University, Columbus, OH, United States
| | - David Jarjoura
- The Sleep Heart Program, the Ohio State University, Columbus, OH, United States
| | - Jay L Zweier
- The Sleep Heart Program, the Ohio State University, Columbus, OH, United States; Division of Pulmonary Critical Care and Sleep, The Davis Heart and Lung Research Institute and Division of Cardiovascular Medicine, the Ohio State University, Columbus, OH, United States
| | - Rami N Khayat
- The Sleep Heart Program, the Ohio State University, Columbus, OH, United States; Division of Pulmonary Critical Care and Sleep, The Davis Heart and Lung Research Institute and Division of Cardiovascular Medicine, the Ohio State University, Columbus, OH, United States.
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Badran M, Golbidi S, Devlin A, Ayas N, Laher I. Chronic intermittent hypoxia causes endothelial dysfunction in a mouse model of diet-induced obesity. Sleep Med 2014; 15:596-602. [DOI: 10.1016/j.sleep.2014.01.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 01/25/2014] [Accepted: 01/30/2014] [Indexed: 11/16/2022]
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Cokic BBB, Cokic VP, Suresh S, Wirt S, Noguchi CT. Nitric oxide and hypoxia stimulate erythropoietin receptor via MAPK kinase in endothelial cells. Microvasc Res 2014; 92:34-40. [PMID: 24518819 DOI: 10.1016/j.mvr.2014.01.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 01/29/2014] [Accepted: 01/31/2014] [Indexed: 12/28/2022]
Abstract
Erythropoietin receptor (EPOR) expression level determines the extent of erythropoietin (EPO) response. Previously we showed that EPOR expression in endothelial cells is increased at low oxygen tension and that EPO stimulation of endothelial cells during hypoxia can increase endothelial nitric oxide (NO) synthase (eNOS) expression and activation as well as NO production. We now observe that while EPO can stimulate NO production, NO in turn can regulate EPOR expression. Human umbilical vein endothelial cells (HUVEC) treated with 10-50 μM of NO donor diethylenetriamine NONOate (DETANO) for 24h showed significant induction of EPOR gene expression at 5% and 2% of oxygen. Also human bone marrow microvascular endothelial cell line (TrHBMEC) cultured at 21 and 2% oxygen with 50 μM DETANO demonstrated a time and oxygen dependent induction of EPOR mRNA expression after 24 and 48 h, particularly at low oxygen tension. EPOR protein was also induced by DETANO at 2% oxygen in TrHBMEC and HUVEC. The activation of signaling pathways by NO donor stimulation appeared to be distinct from EPO stimulation. In reporter gene assays, DETANO treatment of HeLa cells at 2% oxygen increased EPOR promoter activity indicated by a 48% increase in luciferase activity with a 2 kb EPOR promoter fragment and a 71% increase in activity with a minimal EPOR promoter fragment containing 0.2 kb 5'. We found that DETANO activated MAPK kinase in TrHBMEC both in normoxia and hypoxia, while MAPK kinase inhibition showed significant reduction of EPOR mRNA gene expression at low oxygen tension, suggesting MAPK involvement in NO mediated induction of EPOR. Furthermore, DETANO stimulated Akt anti-apoptotic activity after 30 min in normoxia, whereas it inhibited Akt phosphorylation in hypoxia. In contrast, EPO did not significantly increase MAPK activity while EPO stimulated Akt phosphorylation in TrHBMEC in normoxia and hypoxia. These observations provide a new effect of NO on EPOR expression to enhance EPO response in endothelial cells, particularly at low oxygen tensions.
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Affiliation(s)
- Bojana B Beleslin Cokic
- Clinic for Endocrinology, Diabetes and Metabolic Diseases, Genetic Laboratory, Clinical Center of Serbia, Belgrade, Serbia.
| | - Vladan P Cokic
- Laboratory of Experimental Hematology, Institute for Medical Research, University of Belgrade, Belgrade, Serbia
| | - Sukanya Suresh
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Stacey Wirt
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Constance Tom Noguchi
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
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Umbrello M, Dyson A, Feelisch M, Singer M. The key role of nitric oxide in hypoxia: hypoxic vasodilation and energy supply-demand matching. Antioxid Redox Signal 2013; 19:1690-710. [PMID: 23311950 DOI: 10.1089/ars.2012.4979] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
SIGNIFICANCE A mismatch between energy supply and demand induces tissue hypoxia with the potential to cause cell death and organ failure. Whenever arterial oxygen concentration is reduced, increases in blood flow--hypoxic vasodilation--occur in an attempt to restore oxygen supply. Nitric oxide (NO) is a major signaling and effector molecule mediating the body's response to hypoxia, given its unique characteristics of vasodilation (improving blood flow and oxygen supply) and modulation of energetic metabolism (reducing oxygen consumption and promoting utilization of alternative pathways). RECENT ADVANCES This review covers the role of oxygen in metabolism and responses to hypoxia, the hemodynamic and metabolic effects of NO, and mechanisms underlying the involvement of NO in hypoxic vasodilation. Recent insights into NO metabolism will be discussed, including the role for dietary intake of nitrate, endogenous nitrite (NO₂⁻) reductases, and release of NO from storage pools. The processes through which NO levels are elevated during hypoxia are presented, namely, (i) increased synthesis from NO synthases, increased reduction of NO₂⁻ to NO by heme- or pterin-based enzymes and increased release from NO stores, and (ii) reduced deactivation by mitochondrial cytochrome c oxidase. CRITICAL ISSUES Several reviews covered modulation of energetic metabolism by NO, while here we highlight the crucial role NO plays in achieving cardiocirculatory homeostasis during acute hypoxia through both vasodilation and metabolic suppression. FUTURE DIRECTIONS We identify a key position for NO in the body's adaptation to an acute energy supply-demand mismatch.
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Affiliation(s)
- Michele Umbrello
- 1 Department of Medicine, Bloomsbury Institute of Intensive Care Medicine, University College London , London, United Kingdom
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21
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Intermittent maternal hypoxia has an influence on regional expression of endothelial nitric oxide synthase in fetal arteries of rabbits. Pediatr Res 2013; 73:706-12. [PMID: 23478645 DOI: 10.1038/pr.2013.39] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Maternal hypoxia induces sustained fetal adaptations associated with changes in gene expression. We hypothesized that intermittent maternal hypoxia has an influence on regional expression of endothelial nitric oxide synthase (eNOS) in fetal arteries of New Zealand White rabbits. METHODS Timed-pregnant New Zealand White rabbits (term = 30 ± 1 d) were randomly assigned to a normoxic control group (n = 5) or a hypoxia group (12% O2, n = 5) during days 10-29 of pregnancy. At the end of pregnancy (29 d gestation), blood samples were collected from mothers and fetuses. Carotid and femoral arteries of fetuses were extracted for eNOS mRNA and protein concentration and analysis of total NOS activities. RESULTS Our data demonstrate that chronic intermittent maternal hypoxia significantly increased eNOS mRNA and protein concentrations and total NOS activities in carotid artery segments but decreased eNOS mRNA and protein concentrations and total NOS activities in femoral artery segments in the same fetuses. Vascular endothelial cells, but not smooth muscle cells, of fetal rabbits exhibited positive immunostaining for the eNOS protein. CONCLUSION These observations suggest that chronic hypoxia can regulate regional expression of eNOS as an adaptive response to hypoxic stress in fetal arteries.
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22
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Ladage D, Braunroth C, Lenzen E, Berghöfer S, Graf C, Bloch W, Brixius K. Influence of intermittent hypoxia interval training on exercise-dependent erythrocyte NOS activation and blood pressure in diabetic patients. Can J Physiol Pharmacol 2012; 90:1591-8. [DOI: 10.1139/y2012-138] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
NOS-activation in erythrocytes (eryNOS) is impaired in patients suffering from type 2 diabetes. We investigated the effect of physical exercise on eryNOS activation and whether 6 week hypoxia interval training may alter this process. Male patients with diabetes mellitus type 2 (NIDDM, n = 12; age, 61.3 ± 8.4 years; BMI, 29.8 ± 3.7 kg/m2) underwent physical exercise training before and after 6 week hypoxia interval training. Training was conducted 4 times per week for 90 min at 15.4–12.7 Vol% of inspired oxygen. Vital parameters were recorded. Before hypoxia intervention, eryNOS phosphorylation at serine1177decreased significantly during exercise (basal 17.4 ± 12.0 compared with exercise 8.4 ± 9.2 arbitrary grey values (arGV); P < 0.05). After 6 weeks of hypoxia intervention, eryNOS–pSer1177(2.2 ± 2.5 arGV) was significantly lower at baseline. Ergometry showed an increase (7.6 ± 3.0 arGV; P < 0.05) followed by a decrease to almost baseline levels after 30 min (3.8 ± 1.5 arGV). Maximal exercise capacity and O2-uptake ([Formula: see text] max) increased significantly. The effects were independent from exercise-induced elevation of blood pressure. Exercise-dependent eryNOS phosphorylation at serine1177was increased similar to that described for the endothelium in diabetic patients. EryNOS dysregulation was partially restored after intermittent hypoxia training.
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Affiliation(s)
- Dennis Ladage
- Institute for Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark 6, 50933 Cologne, Germany
- Department III of Internal Medicine, University Hospital Cologne, Cologne, Germany
| | - Christian Braunroth
- Institute for Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark 6, 50933 Cologne, Germany
| | - Edward Lenzen
- Institute for Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark 6, 50933 Cologne, Germany
| | - Sandra Berghöfer
- Institute for Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark 6, 50933 Cologne, Germany
| | - Christine Graf
- Department of Preventive and Rehabilitative Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University Cologne, Cologne, Germany
| | - Wilhelm Bloch
- Institute for Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark 6, 50933 Cologne, Germany
| | - Klara Brixius
- Institute for Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark 6, 50933 Cologne, Germany
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Si H, Yu J, Jiang H, Lum H, Liu D. Phytoestrogen genistein up-regulates endothelial nitric oxide synthase expression via activation of cAMP response element-binding protein in human aortic endothelial cells. Endocrinology 2012; 153:3190-8. [PMID: 22669896 PMCID: PMC3791435 DOI: 10.1210/en.2012-1076] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We previously reported that genistein, a phytoestrogen, up-regulates endothelial nitric oxide synthase (eNOS) and prevents hypertension in rats that are independent of estrogen signaling machinery. However, how genistein regulates eNOS expression is unknown. In the present study, we show that genistein enhanced eNOS expression and NO synthesis in primary human aortic endothelial cells. Inhibition of extracellular signal regulated kinase, phosphoinositol-3 kinase, or protein kinase C did not affect genistein-enhanced eNOS expression and NO synthesis. However, chemical inhibition of protein kinase A (PKA) or adenoviral transfer of the specific endogenous PKA inhibitor gene completely abolished PKA activity and genistein-stimulated eNOS expression and NO production. Accordingly, genistein induced PKA activity and subsequent phosphorylation of cAMP response element (CRE)-binding protein (CREB) at Ser133. Suppression of CREB by small interfering RNA transfection abolished genistein-enhanced eNOS expression and NO production. Consistently, deletion of the CRE site within human eNOS promoter eliminated genistein-stimulated eNOS promoter activity. These findings provide the first evidence to our knowledge that genistein may play a beneficial role in vascular function through targeting the PKA/CREB/eNOS/NO signaling pathway.
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Affiliation(s)
- Hongwei Si
- Department of Human Nutrition, Foods, and Exercise, College of Agriculture and Life Sciences, Virginia Tech, Blacksburg, Virginia 24061, USA
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Araújo AV, Ferezin CZ, C. Pereira AD, Rodrigues GJ, Grando MD, Bonaventura D, Bendhack LM. Augmented nitric oxide production and up-regulation of endothelial nitric oxide synthase during cecal ligation and perforation. Nitric Oxide 2012; 27:59-66. [DOI: 10.1016/j.niox.2012.04.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 04/12/2012] [Accepted: 04/17/2012] [Indexed: 12/24/2022]
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Matsubara K, Harada H, Ando N, Watada S, Obara H, Matsumoto K, Kitagawa Y. Estrogen deficiency attenuates neovascularization in a murine model of hindlimb ischemia. J Surg Res 2012; 178:1022-8. [PMID: 22632940 DOI: 10.1016/j.jss.2012.04.067] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 04/17/2012] [Accepted: 04/27/2012] [Indexed: 11/26/2022]
Abstract
BACKGROUND The possible relation between menopause and the development of peripheral arterial disease, especially lower extremity disease, has not been fully studied. To explore this issue, we investigated whether estrogen deficiency affected neovascularization in a murine model of hindlimb ischemia. METHODS Ischemia was surgically induced in one hindlimb of oophorectomized and control female BALB/c mice. Neovascularization in the ischemic hindlimbs was evaluated using laser Doppler blood flow analysis and capillary density analysis of the adductor muscle. The expression of endothelial nitric oxide synthase protein in the adductor muscle of the ischemic hindlimbs was assessed. RESULTS The plasma 17-β estradiol levels were significantly lower in the oophorectomized mice than in the control mice. The oophorectomized mice also had a significantly reduced blood perfusion index and capillary density on day 21 after the induction of hindlimb ischemia and significant suppression of endothelial nitric oxide synthase protein expression on day 3 after ischemia induction. CONCLUSIONS Estrogen deficiency attenuated neovascularization in a murine model of hindlimb ischemia. Impaired neovascularization in oophorectomized mice might correlate with a reduction in endothelial nitric oxide synthase expression caused by estrogen deficiency.
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Affiliation(s)
- Kentaro Matsubara
- Department of Surgery, Keio University School of Medicine, Tokyo, Japan
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Zong F, Zuo XR, Wang Q, Zhang SJ, Xie WP, Wang H. Iptakalim rescues human pulmonary artery endothelial cells from hypoxia-induced nitric oxide system dysfunction. Exp Ther Med 2011; 3:535-539. [PMID: 22969925 DOI: 10.3892/etm.2011.414] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 11/22/2011] [Indexed: 11/06/2022] Open
Abstract
The aim of this study was to assess whether hypoxia inhibits endothelial nitric oxide synthase (eNOS) activity and nitric oxide (NO) production, and whether iptakalim may rescue human pulmonary artery endothelial cells (HPAECs) from hypoxia-induced NO system dysfunction. HPAECs were cultured under hypoxic conditions in the absence or presence of 0.1, 10 and 1,000 μM iptakalim or the combination of 10 μM iptakalim and 1, 10 and 100 μM glibenclamide for 24 h, and the eNOS activity and NO levels were measured in the conditioned medium from the HPAEC cultures. The eNOS activity and NO levels were reduced significantly in the conditioned medium from HPAEC cultures under hypoxic conditions. Pre-treatment with 10 μM iptakalim normalized the reduction of the eNOS activity and NO levels caused by hypoxia in the conditioned medium from HPAEC cultures. Iptakalim raised the eNOS activity and NO levels under hypoxic conditions, but was blocked by the K(ATP) channel blocker, glibenclamide. Our results indicate that hypoxia impairs NO system function, whereas the ATP-sensitive K(+) channel opener, iptakalim, may rescue HPAECs from hypoxia-induced NO system dysfunction.
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Sandvik GK, Nilsson GE, Jensen FB. Dramatic increase of nitrite levels in hearts of anoxia-exposed crucian carp supporting a role in cardioprotection. Am J Physiol Regul Integr Comp Physiol 2011; 302:R468-77. [PMID: 22129619 DOI: 10.1152/ajpregu.00538.2011] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Nitrite (NO(2)(-)) functions as an important nitric oxide (NO) donor under hypoxic conditions. Both nitrite and NO have been found to protect the mammalian heart and other tissues against ischemia (anoxia)-reoxygenation injury by interacting with mitochondrial electron transport complexes and limiting the generation of reactive oxygen species upon reoxygenation. The crucian carp naturally survives extended periods without oxygen in an active state, which has made it a model for studying how evolution has solved the problems of anoxic survival. We investigated the role of nitrite and NO in the anoxia tolerance of this fish by measuring NO metabolites in normoxic, anoxic, and reoxygenated crucian carp. We also cloned and sequenced crucian carp NO synthase variants and quantified their mRNA levels in several tissues in normoxia and anoxia. Despite falling levels of blood plasma nitrite, the crucian carp showed massive increases in nitrite, S-nitrosothiols (SNO), and iron-nitrosyl (FeNO) compounds in anoxic heart tissue. NO(2)(-) levels were maintained in anoxic brain, liver, and gill tissues, whereas SNO and FeNO increased in a tissue-specific manner. Reoxygenation reestablished normoxic values. We conclude that NO(2)(-) is shifted into the tissues where it acts as NO donor during anoxia, inducing cytoprotection under anoxia/reoxygenation. This can be especially important in the crucian carp heart, which maintains output in anoxia. NO(2)(-) is currently tested as a therapeutic drug against reperfusion damage of ischemic hearts, and the present study provides evolutionary precedent for such an approach.
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Affiliation(s)
- Guro K Sandvik
- Department of Molecular Biosciences, University of Oslo, Oslo, Norway.
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Feng GM, Chen JH, Lin CI, Yang JM. Effect of docosahexaenoic acid on hypoxia/reoxygenation injury in human coronary arterial smooth muscle cells. Eur J Nutr 2011; 51:987-95. [DOI: 10.1007/s00394-011-0278-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Accepted: 11/07/2011] [Indexed: 12/18/2022]
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Krause B, Hanson M, Casanello P. Role of nitric oxide in placental vascular development and function. Placenta 2011; 32:797-805. [PMID: 21798594 PMCID: PMC3218217 DOI: 10.1016/j.placenta.2011.06.025] [Citation(s) in RCA: 145] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 06/28/2011] [Accepted: 06/29/2011] [Indexed: 11/27/2022]
Abstract
Nitric oxide (NO) is one of the most pleiotropic signaling molecules at systemic and cellular levels, participating in vascular tone regulation, cellular respiration, proliferation, apoptosis and gene expression. Indeed NO actively participates in trophoblast invasion, placental development and represents the main vasodilator in this tissue. Despite the large number of studies addressing the role of NO in the placenta, its participation in placental vascular development and the effect of altered levels of NO on placental function remains to be clarified. This review draws a time-line of the participation of NO throughout placental vascular development, from the differentiation of vascular precursors to the consolidation of vascular function are considered. The influence of NO on cell types involved in the origin of the placental vasculature and the expression and function of the nitric oxide synthases (NOS) throughout pregnancy are described. The developmental processes involved in the placental vascular bed are considered, such as the participation of NO in placental vasculogenesis and angiogenesis through VEGF and Angiopoietin signaling molecules. The role of NO in vascular function once the placental vascular tree has developed, in normal pregnancy as well as in pregnancy-related diseases, is then discussed.
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Affiliation(s)
- B.J. Krause
- Division of Obstetrics and Gynecology, School of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - M.A. Hanson
- Institute of Developmental Sciences, Academic Unit of Human Development & Health, Faculty of Medicine, University of Southampton, SO16 6YD, UK
| | - P. Casanello
- Division of Obstetrics and Gynecology, School of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
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Rus A, Del Moral ML, Molina F, Peinado MA. Upregulation of cardiac NO/NOS system during short-term hypoxia and the subsequent reoxygenation period. Eur J Histochem 2011; 55:e17. [PMID: 22193297 PMCID: PMC3284153 DOI: 10.4081/ejh.2011.e17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 04/06/2011] [Accepted: 04/08/2011] [Indexed: 01/05/2023] Open
Abstract
Hypoxia/reoxygenation (H/R) reportedly influences nitric oxide (NO) production and NO synthase (NOS) expression in the heart. Nonetheless, a number of works have shown controversial results regarding the changes that the cardiac NO/NOS system undergoes under such situations. Therefore, this study aims to clarify the behaviour of this system in the hypoxic heart by investigating seven different reoxygenation times. Wistar rats were submitted to H/R (hypoxia for 30 min; reoxygenation of 0, 2, 12, 24, 48, 72 h, and 5 days) in a novel approach to address the events provoked by assaults under such circumstances. Endothelial and inducible NOS (eNOS and iNOS) mRNA and protein expression, as well as enzymatic activity and enzyme location were determined. NO levels were indirectly quantified as nitrate/nitrite, and other S-nitroso compounds (NOx), which would act as NO-storage molecules. The results showed a significant increase in eNOS mRNA, protein and activity, as well as in NOx levels immediately after hypoxia, while iNOS protein and activity were induced throughout the reoxygenation period. These findings indicate that, not only short-term hypoxia, but also the subsequent reoxygenation period upregulate cardiac NO/NOS system until at least 5 days after the hypoxic stimulus, implying major involvement of this system in the changes occurring in the heart in response to H/R.
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Affiliation(s)
- A Rus
- Department of Experimental Biology (Building B-3), University of Jaén,Campus Las Lagunillas s/n, 23071 Jaén, Spain.
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Rus A, Peinado MA, Castro L, Del Moral ML. Lung eNOS and iNOS are reoxygenation time-dependent upregulated after acute hypoxia. Anat Rec (Hoboken) 2010; 293:1089-98. [PMID: 20225207 DOI: 10.1002/ar.21141] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Nitric oxide plays a critical role in many physiological and physiopathological processes in the lung. Changes in the NO/NOS (Nitric Oxide/Nitric Oxide Synthase) system after hypoxia situations remain controversial in this organ, so that the aim of this work is to perform a complete study of this system in the hypoxic lung after different reoxygenation times ranging from 0 h to 5 days posthypoxia. This is a novel follow-up study carried out in Wistar rats submitted for 30 min to acute hypobaric hypoxia. We measured endothelial and inducible NOS (eNOS, iNOS) mRNA and protein expression, location, and in situ NOS activity as well as nitrated protein expression and location. In addition, NO levels were indirectly quantified (NOx) as well as the apoptosis level. Results showed an increase in eNOS mRNA, protein, activity as well as eNOS positive immunostaining at 0 h posthypoxia, coinciding with raised NOx levels. Contrary, iNOS, nitrated protein expression and apoptosis level augmented during the final reoxygenation times. The lung NO/NOS system provokes two responses to the hypoxia/reoxygenation processes: (i) eNOS is responsible of the immediate response, producing NO, which causes vasodilation and bronchodilation, and (ii) iNOS is related to the second late response, which seems to be involved in some of the deleterious consequences that hypoxia induces in the lung.
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Affiliation(s)
- Alma Rus
- Department of Experimental Biology, University of Jaén, Jaén, Spain
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32
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Exogenous expression of HIF-1α promotes cardiac differentiation of embryonic stem cells. J Mol Cell Cardiol 2010; 48:1129-37. [DOI: 10.1016/j.yjmcc.2010.01.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Revised: 01/05/2010] [Accepted: 01/20/2010] [Indexed: 11/19/2022]
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Perrotta I, Brunelli E, Sciangula A, Zuccalà V, Donato G, Tripepi S, Martinelli GL, Cassese M. Inducible and endothelial nitric oxide synthase expression in human atherogenesis: an immunohistochemical and ultrastructural study. Cardiovasc Pathol 2009; 18:361-8. [DOI: 10.1016/j.carpath.2008.08.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Revised: 06/25/2008] [Accepted: 08/19/2008] [Indexed: 10/21/2022] Open
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Goldenberg-Cohen N, Dadon-Bar-El S, Hasanreisoglu M, Avraham-Lubin BCR, Dratviman-Storobinsky O, Cohen Y, Weinberger D. Possible neuroprotective effect of brimonidine in a mouse model of ischaemic optic neuropathy. Clin Exp Ophthalmol 2009; 37:718-29. [DOI: 10.1111/j.1442-9071.2009.02108.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Endothelial activation and inflammation are important mediators of accelerated atherogenesis and consequent increased cardiovascular morbidity in obstructive sleep apnea (OSA). Repetitive episodes of hypoxia/reoxygenation associated with transient cessation of breathing during sleep in OSA resemble ischemia/reperfusion injury and may be the main culprit underlying endothelial dysfunction in OSA. Additional factors such as repetitive arousals resulting in sleep fragmentation and deprivation and individual genetic suseptibility to vascular manifestations of OSA contribute to impaired endothelial function in OSA. The present review focuses on possible mechanisms that underlie endothelial activation and inflammation in OSA.
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Affiliation(s)
- Amy Atkeson
- Division of Pulmonary, Allergy, and Critical Care Medicine, Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032, USA
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36
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Thompson L, Dong Y, Evans L. Chronic hypoxia increases inducible NOS-derived nitric oxide in fetal guinea pig hearts. Pediatr Res 2009; 65:188-92. [PMID: 19047955 PMCID: PMC6314287 DOI: 10.1203/pdr.0b013e31818d6ad0] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Intrauterine hypoxia impacts fetal growth and organ function. Inducible nitric oxide synthase (iNOS) and neuronal NOS (nNOS) expression was measured to assess the response of fetal hearts to hypoxic (HPX) stress. Pregnant guinea pigs were housed in a hypoxic chamber (10.5% O2 for 14 d, n = 17) or room air [normoxic (NMX), n = 17]. Hearts of anesthetized near-term fetuses were removed. mRNA [hypoxia-inducible factor, (HIF)-1alpha, 1beta, 2alpha, 3alpha, iNOS, and nNOS] and protein levels (HIF-1alpha, iNOS, and nNOS) of fetal cardiac left ventricles were quantified by real time polymerase chain reaction (PCR) and Western analysis, respectively. Cardiac nitrite/nitrate levels were measured in the presence/absence of L-N6-(1-iminoethyl)-lysine (L-NIL), an iNOS inhibitor, administered to pregnant sows. Hypoxia significantly increased fetal cardiac HIF-1alpha and -2alpha mRNA, HIF-1alpha protein but not HIF-3alpha or -1beta mRNA levels. Hypoxia increased both iNOS mRNA (by 5x) and protein (by 23%) levels but had no effect on nNOS levels. Nitrite/nitrate levels were increased in HPX hearts by 2.5x and decreased with L-NIL by 67 +/- 14%. Thus, up-regulation of iNOS-derived nitric oxide (NO) generation is an important mechanism by which fetal hearts respond to chronic hypoxic stress.
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Affiliation(s)
- Loren Thompson
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
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37
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Kravchenko NA, Yarmysh NV. Regulation of the expression of endothelial nitric oxide synthase and dysfunction of vascular endothelium in cardiovascular pathology. CYTOL GENET+ 2008. [DOI: 10.3103/s0095452708040117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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38
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Ostergaard L, Stankevicius E, Andersen MR, Eskildsen-Helmond Y, Ledet T, Mulvany MJ, Simonsen U. Diminished NO release in chronic hypoxic human endothelial cells. Am J Physiol Heart Circ Physiol 2007; 293:H2894-903. [PMID: 17720765 DOI: 10.1152/ajpheart.01230.2006] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The present study addressed whether chronic hypoxia is associated with reduced nitric oxide (NO) release due to decreased activation of endothelial NO synthase (eNOS). Primary cultures of endothelial cells from human umbilical veins (HUVECs) were used and exposed to different oxygen levels for 24 h, after which NO release, intracellular calcium, and eNOS activity and phosphorylation were measured after 24 h. Direct measurements using a NO microsensor showed that in contrast to 1-h exposure to 5% and 1% oxygen (acute hypoxia), histamine-evoked (10 μM) NO release from endothelial cells exposed to 5% and 1% oxygen for 24 h (chronic hypoxia) was reduced by, respectively, 58% and 40%. Furthermore, chronic hypoxia also lowered the amount and activity of eNOS enzyme. The decrease in activity could be accounted for by reduced intracellular calcium and altered eNOS phosphorylation. eNOS Ser1177 and eNOS Thr495 phosphorylations were reduced and increased, respectively, consistent with lowered enzyme activity. Akt kinase, which can phosphorylate eNOS Ser1177, was also decreased by hypoxia, regarding both total protein content and the phosphorylated (active) form. Moreover, the protein content of β- actin, which is known to influence the activity of eNOS, was almost halved by hypoxia, further supporting the fall in eNOS activity. In conclusion, chronic hypoxia in HUVECs reduces histamine-induced NO release as well as eNOS expression and activity. The decreased activity is most likely due to changed eNOS phosphorylation, which is supported by decreases in Akt expression and phosphorylation. By reducing NO, chronic hypoxia may accentuate endothelial dysfunction in cardiovascular disease.
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Couloubaly S, Deloménie C, Rousseau D, Paul JL, Grynberg A, Pourci ML. Fatty acid incorporation in endothelial cells and effects on endothelial nitric oxide synthase. Eur J Clin Invest 2007; 37:692-9. [PMID: 17696958 DOI: 10.1111/j.1365-2362.2007.01843.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND The nature of fatty acids provided by the diet as well as plasma lipid metabolism can modify the composition and properties of plasma membrane and thus the activity of membrane proteins. In humans, as well as in experimental models, diabetes is associated with both an alteration in serum lipid profile and a documented endothelial dysfunction. This in vitro study investigated on an immortalized human endothelial cell line (EA.hy 926) the specific effects of several free fatty acids (FFAs) on the composition of cellular membranes and the regulation of endothelial nitric oxide synthase (eNOS). MATERIALS AND METHODS 0.1% of lipid deprived serum was added to the incubation medium with 25 mM glucose in order to study the effects of individual fatty acids: myristic acid, palmitic acid, stearic acid, oleic acid or linoleic acid at 100 microM bound with albumin. The effects of the FFAs on the endothelial nitric oxide synthase were investigated on mRNA level by quantitative PCR, on protein level and Ser1177 phosphorylation by Western blot and on enzymatic activity on living cells using radiolabelled arginine. RESULTS Free linoleic acid increased the membrane content in n-6 fatty acids (mainly C18: n-6 and its metabolites) with a decrease in saturated and monounsaturated fatty acids. These conditions decreased the basal eNOS activity and reduced the phosphorylation of eNOS-Ser1177 due to activation by histamine. Free palmitic acid enriched the membranes with 16 : 0 with a slight decrease in monounsaturated fatty acids. These conditions increased eNOS activation without increasing Ser1177 phosphorylation upon histamine activation. The addition of the other FFAs also resulted in modifications of membrane composition, which did not to affect eNOS-Ser1177 phosphorylation. CONCLUSION Among the fatty acids used, only modification of the membrane composition due to linoleic acid supply disturbed the basal enzymatic activity and Ser1177 phosphorylation of eNOS in a way that limited the role of histamine activation. Linoleic acid might involve the dysfunction of both eNOS basal activity and its phosphorylation status and may then contribute to an impaired vasodilatation in vivo.
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Affiliation(s)
- S Couloubaly
- UMR 1154-INRA, and IFR 141, Université Paris-Sud11, Châtenay-Malabry, France
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40
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Shen JS, Meng XL, Schiffmann R, Brady RO, Kaneski CR. Establishment and characterization of Fabry disease endothelial cells with an extended lifespan. Mol Genet Metab 2007; 92:137-44. [PMID: 17644384 PMCID: PMC2063578 DOI: 10.1016/j.ymgme.2007.06.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2007] [Revised: 06/05/2007] [Accepted: 06/05/2007] [Indexed: 11/20/2022]
Abstract
Fabry disease is an inborn error of glycosphingolipid catabolism resulting from a deficiency of lysosomal enzyme alpha-galactosidase A. The major clinical manifestations of the disease, such as stroke, cardiac dysfunction, and renal impairment, are thought to be caused by vasculopathy due to progressive accumulation of globotriaosylceramide in vascular endothelial cells. The pathogenesis of the vasculopathy has not been elucidated. Since in vitro studies using primary endothelial cells are hampered by the limited lifespan of these cells, the availability of cultured endothelial cells with an extended lifespan is critical for the study of the vasculopathy of Fabry disease. We therefore generated an endothelial cell line from a Fabry hemizygote by introduction of human telomerase reverse transcriptase gene. The cell line has markedly extended lifespan compared to parental primary cells. The cells stably express many key markers of endothelial cells such as von Willebrand factor, CD31, CD34, and endothelial nitric oxide synthase (eNOS) and retain functional characteristics such as uptake of acetylated low-density lipoprotein, responsiveness to angiogenic growth factors, up-regulation of eNOS production upon extracellular stimuli, and formation of tube-like structures on Matrigel basement membrane matrix. The cells show significantly reduced activity of alpha-galactosidase A compared with primary endothelial cells from normal individuals and accumulate globotriaosylceramide in lysosomes. This cell line will provide a useful in vitro model of Fabry disease and will facilitate systematic studies to investigate pathogenic mechanisms and explore new therapeutic approaches for Fabry disease.
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Affiliation(s)
- Jin-Song Shen
- Developmental and Metabolic Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health
| | - Xing-Li Meng
- Laboratory of Clinical Genomics, National Institute of Child Health and Human Development, National Institutes of Health
| | - Raphael Schiffmann
- Developmental and Metabolic Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health
| | - Roscoe O. Brady
- Developmental and Metabolic Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health
| | - Christine R. Kaneski
- Developmental and Metabolic Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health
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Turnbull CM, Rossi AG, Megson IL. Therapeutic effects of nitric oxide-aspirin hybrid drugs. Expert Opin Ther Targets 2007; 10:911-22. [PMID: 17105376 DOI: 10.1517/14728222.10.6.911] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
This review examines the therapeutic potential and mechanisms of action of drugs known as nitric oxide (NO)-aspirins. Drugs of this class have an NO-releasing moiety joined by ester linkage to the aspirin molecule. NO-aspirins have the capability to release NO in addition to retaining the cyclooxygenase-inhibitory action of aspirin. The protective nature of NO led to the development of NO-aspirins in the hope that they might avoid the gastric side effects associated with aspirin. However, it has become apparent that the drug-derived NO instills potential for a wide range of added beneficial effects over the parent compound. In this review, the authors focus on the analgesic, anti-inflammatory, cardiovascular and chemopreventative actions of compounds of this emerging drug class.
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Affiliation(s)
- Catriona M Turnbull
- Queen's Medical Research Institute, University of Edinburgh, Centre for Cardiovascular Science, Edinburgh, EH16 4TJ, UK.
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42
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Xing XQ, Gan Y, Wu SJ, Chen P, Zhou R, Xiang XD. Statins may ameliorate pulmonary hypertension via RhoA/Rho-kinase signaling pathway. Med Hypotheses 2007; 68:1108-13. [PMID: 17097823 DOI: 10.1016/j.mehy.2006.09.034] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Accepted: 09/06/2006] [Indexed: 02/08/2023]
Abstract
Statins are the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors that function as potent inhibitors of cholesterol biosynthesis and have been used for many years for the treatment of hypercholesterolemia. However, accumulating experimental and clinical studies have revealed that the health benefits associated with statins treatment, particularly those conferred on the cardiovascular system, were the cholesterol-independent. Because statins inhibit an early step in the cholesterol biosynthetic pathway, they also inhibit the synthesis of isoprenoids such as farnesylpyrophosphate and geranylgeranylpyrophosphate, which are important postranslational lipid attachments for intracellular signaling molecules such as the Rho GTPases. The isoprenylation of Rho is a prerequisite for Rho activation, facilitating its interaction with the plasma membrane, undergoing GDP-GTP exchange and be activated. Inhibition of RhoA geranylgeranylation by statins decreases membrane GTP-bound active RhoA and subsequent Rho-kinase activity. Activated RhoA via its downstream effector Rho-kinase is involved in a wide range of cellular functions, such as cell migration, proliferation and apoptosis. Recently, rising evidences suggested that RhoA/Rho-kinase pathway was essentially involved in various models of pulmonary hypertension and statins effectively ameliorated pulmonary hypertension. Based on this findings, we hypothesis that statins attenuate pulmonary hypertension via RhoA/Rho-kinase signaling pathway in vivo.
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Affiliation(s)
- Xi-Qian Xing
- Department of Respiratory Medicine, The Second Xiangya Hospital, Central South University, Middle Renmin Road, No. 86, Changsha, Hunan 410011, PR China
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Li R, Guo M, Zhang G, Xu X, Li Q. Nicotiflorin reduces cerebral ischemic damage and upregulates endothelial nitric oxide synthase in primarily cultured rat cerebral blood vessel endothelial cells. JOURNAL OF ETHNOPHARMACOLOGY 2006; 107:143-50. [PMID: 16806761 DOI: 10.1016/j.jep.2006.04.024] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2005] [Revised: 04/21/2006] [Accepted: 04/29/2006] [Indexed: 05/09/2023]
Abstract
Nicotiflorin is a flavonoid glycoside extracted from a traditional Chinese medicine Flos Carthami. In the current study, we investigated the neuroprotective effect of nicotiflorin on a transient focal cerebral ischemia-reperfusion model in rats. Nicotiflorin (2.5-10 mg/kg) administered after onset of ischemia markedly reduced brain infarct volume by 24.5-63.2% and neurological deficits. Also the effect of nicotiflorin on endothelial nitric oxide synthase (eNOS) activity, mRNA and protein expression after hypoxia-reoxygenation (H-R) treatment was investigated in an in vitro model mimic cerebrum ischemia-reperfusion in vivo. After total 4 h hypoxia and 12 h reoxygenation, eNOS activity, mRNA and protein levels in the primarily cultured rat cerebral blood vessel endothelial cells treated with nicotiflorin (25-100 microg/ml) 2 h after onset of hypoxia were significantly higher than eNOS activity, mRNA and protein levels in the pure H-R cells and also higher than eNOS activity, mRNA and protein levels in cells cultured under normoxic conditions. The results demonstrated that nicotiflorin had a protective effect against cerebral ischemic damage. The results also gave an important elucidation for the mechanism underlying the protective effect at the cellular level.
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Affiliation(s)
- Runping Li
- Department of Diving Medicine, Faculty of Navy Medicine, Second Military Medical University, Shanghai, People's Republic of China
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Saura M, Zaragoza C, Bao C, Herranz B, Rodriguez-Puyol M, Lowenstein CJ. Stat3 mediates interleukin-6 [correction of interelukin-6] inhibition of human endothelial nitric-oxide synthase expression. J Biol Chem 2006; 281:30057-62. [PMID: 16887796 DOI: 10.1074/jbc.m606279200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chronic activation of the acute phase response (APR) is associated with atherosclerosis. Elevated levels of interleukin-6, the major inducer of the APR, are associated with an increased risk of cardiovascular events. One of the clinical hallmarks of atherogenesis is endothelial dysfunction, characterized by a decrease in endothelial production of nitric oxide (NO). We hypothesized that interleukin-6 (IL-6) decreases endothelial NO synthase (eNOS) expression. We now show that IL-6 treatment of human aortic endothelial cells (HAEC) decreases steady-state levels of human eNOS mRNA and protein. This decrease in eNOS expression is caused in part by IL-6 inhibition of transactivation of the human eNOS promoter. To explore the mechanism by which IL-6 affects eNOS expression, we examined activation of signal transducer and transactivator-3 (Stat3). The IL-6 receptor (IL-6R) is expressed in HAEC, and Stat3 is phosphorylated in response to IL-6 stimulation of the IL-6R. We identified four consensus sequences for Stat3 binding (SIE) in the eNOS promoter at positions -1520, -1024, -840, and -540. Transfection of eNOS promoter mutants revealed that the SIE at -1024 mediates Stat3 inhibition of eNOS promoter activity. Gel-shift analysis of nuclear extracts from HAEC treated with IL-6 confirms that Stat3 binds to a complex containing the SIE at -1024. RNA silencing of STAT3 blocks the inhibitory effect of IL-6 on eNOS expression. Our data show that IL-6 has direct effects upon endothelial cells, inhibiting eNOS expression in part through Stat3. Decreased levels of eNOS may be an important component of the pro-atherogenic effect of the APR.
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Affiliation(s)
- Marta Saura
- Department of Physiology, Universidad de Alcalá, Alcalá de Henares, 28871 Madrid, Spain
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45
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Anttila V, Christou H, Hagino I, Iwata Y, Mettler BA, Fernandez-Gonzalez A, Zurakowski D, Jonas RA. Cerebral Endothelial Nitric Oxide Synthase Expression is Reduced After Very Low Flow Bypass. Ann Thorac Surg 2006; 81:2202-6. [PMID: 16731155 DOI: 10.1016/j.athoracsur.2006.01.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2005] [Revised: 01/03/2006] [Accepted: 01/04/2006] [Indexed: 11/29/2022]
Abstract
BACKGROUND In previous studies we have shown that delayed capillary reperfusion after low flow bypass predicts neurologic injury. In this acute study, we hypothesized that low flow reduces endothelial nitric oxide synthase (eNOS) expression, which may lead to more profound inflammatory response and delayed capillary perfusion. METHODS Twelve piglets (13.2 +/- 0.7 kg) had a cranial window placed over the parietal cerebral cortex for direct examination of the microcirculation using intravital fluorescence microscopy. Animals were cooled to 15 degrees C or 34 degrees C on cardiopulmonary bypass (pH stat, hematocrit 30%, pump flow 100 mL/kg/minute) followed by 2 hours of low flow (50 mL/kg/minute) or very low flow (10 mL/kg/minute). Rhodamine staining was used to observe adherent and rolling leukocytes in postcapillary venules. The eNOS protein expression was determined by Western immunoblotting. RESULTS High temperature and low flow rate correlated with significantly reduced eNOS expression (p < 0.01). Univariate comparisons based on Student t tests indicated that eNOS protein levels were lower at 34 degrees C than at 15 degrees C (0.7 +/- 0.6 vs 1.7 +/- 0.5, p < 0.01) and at 10 mL/kg per minute compared with 50 mL/kg per minute (0.8 +/- 0.7 vs 1.6 +/- 0.5, p = 0.03). Moreover, two-way analysis of variance revealed that temperature (F = 21.6, p < 0.001) and flow rate (F = 13.8, p = 0.005) were independent multivariate predictors of eNOS expression. During low flow bypass, eNOS was inversely correlated with numbers of adherent (p = 0.002) and rolling (p = 0.006) leukocytes, following an exponential decay curve closely. CONCLUSIONS eNOS expression is reduced after very low flow bypass, particularly at a higher bypass temperature. This is associated with delayed capillary reperfusion. Reduced eNOS is also associated with increased white cell activation which may lead to greater neurologic injury.
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Affiliation(s)
- Vesa Anttila
- Department of Cardiovascular Surgery, Children's Hospital, Boston, Massachusetts, USA
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46
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Searles CD. Transcriptional and posttranscriptional regulation of endothelial nitric oxide synthase expression. Am J Physiol Cell Physiol 2006; 291:C803-16. [PMID: 16738003 DOI: 10.1152/ajpcell.00457.2005] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The ability of the endothelium to produce nitric oxide is essential to maintenance of vascular homeostasis; disturbance of this ability is a major contributor to the pathogenesis of vascular disease. In vivo studies have demonstrated that expression of endothelial nitric oxide synthase (eNOS) is vital to endothelial function and have led to the understanding that eNOS expression is subject to modest but significant degrees of regulation. Subsequently, numerous physiological and pathophysiological stimuli have been identified that modulate eNOS expression via mechanisms that alter steady-state eNOS mRNA levels. These mechanisms involve changes in the rate of eNOS gene transcription (transcriptional regulation) and alteration of eNOS mRNA processing and stability (posttranscriptional regulation). In cultured endothelial cells, shear stress, transforming growth factor-beta1, lysophosphatidylcholine, cell growth, oxidized linoleic acid, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, and hydrogen peroxide have been shown to increase eNOS expression. In contrast, tumor necrosis factor-alpha, hypoxia, lipopolysaccaride, thrombin, and oxidized LDL can decrease eNOS mRNA levels. For many of these stimuli, both transcriptional and posttranscriptional mechanisms contribute to regulation of eNOS expression. Recent studies have begun to further define signaling pathways responsible for changes in eNOS expression and have characterized cis- and trans-acting regulatory elements. In addition, a role has been identified for epigenetic control of eNOS mRNA levels. This review will discuss transcriptional and posttranscriptional regulation of eNOS with emphasis on the molecular mechanisms that have been identified for these processes.
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Affiliation(s)
- Charles D Searles
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA.
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47
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Walsh MP, Marshall JM. The early effects of chronic hypoxia on the cardiovascular system in the rat: role of nitric oxide. J Physiol 2006; 575:263-75. [PMID: 16690711 PMCID: PMC1819421 DOI: 10.1113/jphysiol.2006.108753] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Experiments were performed under Saffan anaesthesia on normoxic (N) rats and on chronically hypoxic rats exposed to 12% O2 for 1, 3 or 7 days (1, 3 or 7CH rats): N rats routinely breathed 21% O2 and CH rats 12% O2. The 1, 3 and 7CH rats showed resting hyperventilation relative to N rats, but baseline heart rate (HR) was unchanged and arterial blood pressure (ABP) was lowered. Femoral vascular conductance (FVC) was increased in 1 and 3CH rats, but not 7CH rats. When 1-7CH rats were acutely switched to breathing 21% O2 for 5 min, ABP increased and FVC decreased, consistent with removal of a hypoxic dilator stimulus that is waning in 7CH rats. We propose that this is because the increase in haematocrit and vascular remodelling in skeletal muscle help restore the O2 supply. The increases in FVC evoked by acute hypoxia (8% O2 for 5 min) and by infusion for 5 min of alpha-calcitonin gene-related peptide (alpha-CGRP), which are NO-dependent, were particularly accentuated in 1CH, relative to N rats. The NO synthesis inhibitor L-NAME increased ABP, decreased HR and greatly reduced FVC, and attenuated increases in FVC evoked by acute hypoxia and alpha-CGRP, such that baselines and responses were similar in N and 1-7CH rats. We propose that in the first few days of chronic hypoxia there is tonic NO-dependent vasodilatation in skeletal muscle that is associated with accentuated dilator responsiveness to acute hypoxia and dilator substances that are NO -dependent.
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Affiliation(s)
- Martin P Walsh
- Department of Physiology, The Medical School, Birmingham B15 2TT, UK
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48
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Min J, Jin YM, Moon JS, Sung MS, Jo SA, Jo I. Hypoxia-induced endothelial NO synthase gene transcriptional activation is mediated through the tax-responsive element in endothelial cells. Hypertension 2006; 47:1189-96. [PMID: 16651461 DOI: 10.1161/01.hyp.0000222892.37375.4d] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Although hypoxia is known to induce upregulation of endothelial NO synthase (eNOS) gene expression, the underlying mechanism is largely unclear. In this study, we show that hypoxia increases eNOS gene expression through the binding of phosphorylated cAMP-responsive element binding (CREB) protein (pCREB) to the eNOS gene promoter. Hypoxia (1% O2) increased both eNOS expression and NO production, peaking at 24 hours, in bovine aortic endothelial cells, and these increases were accompanied by increases in pCREB. Treatment with the protein kinase A inhibitor H-89 or transfection with dominant-negative inhibitor of CREB reversed the hypoxia-induced increases in eNOS expression and NO production, with concomitant inhibition of the phosphorylation of CREB induced by hypoxia, suggesting an involvement of protein kinase A/pCREB-mediated pathway. To map the regulatory elements of the eNOS gene responsible for pCREB binding under hypoxia, we constructed an eNOS gene promoter (-1600 to +22 nucleotides) fused with a luciferase reporter gene [pGL2-eNOS(-1600)]. Hypoxia (for 24-hour incubation) increased the promoter activity by 2.36+/-0.18-fold in the bovine aortic endothelial cells transfected with pGL2-eNOS(-1600). However, progressive 5'-deletion from -1600 to -873 completely attenuated the hypoxia-induced increase in promoter activity. Electrophoretic mobility shift, anti-pCREB antibody supershift, and site-specific mutation analyses showed that pCREB is bound to the Tax-responsive element (TRE) site, a cAMP-responsive element-like site, located at -924 to -921 of the eNOS promoter. Our data demonstrate that the interaction between pCREB and the Tax-responsive element site within the eNOS promoter may represent a novel mechanism for the mediation of hypoxia-stimulated eNOS gene expression.
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Affiliation(s)
- Jiho Min
- Department of Biomedical Sciences, National Institute of Health, 194 Tongilo, Eunpyeong-gu, Seoul 122-701, Korea
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49
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Dudzinski DM, Igarashi J, Greif D, Michel T. The regulation and pharmacology of endothelial nitric oxide synthase. Annu Rev Pharmacol Toxicol 2006; 46:235-76. [PMID: 16402905 DOI: 10.1146/annurev.pharmtox.44.101802.121844] [Citation(s) in RCA: 283] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Nitric oxide (NO) is a small, diffusible, lipophilic free radical gas that mediates significant and diverse signaling functions in nearly every organ system in the body. The endothelial isoform of nitric oxide synthase (eNOS) is a key source of NO found in the cardiovascular system. This review summarizes the pharmacology of NO and the cellular regulation of endothelial NOS (eNOS). The molecular intricacies of the chemistry of NO and the enzymology of NOSs are discussed, followed by a review of the biological activities of NO. This information is then used to develop a more global picture of the pharmacological control of NO synthesis by NOSs in both physiologic conditions and pathophysiologic states.
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Affiliation(s)
- David M Dudzinski
- Cardiovascular Division, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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50
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Thompson LP, Dong Y. Chronic hypoxia decreases endothelial nitric oxide synthase protein expression in fetal guinea pig hearts. ACTA ACUST UNITED AC 2006; 12:388-95. [PMID: 15982907 DOI: 10.1016/j.jsgi.2005.04.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVES The underlying cellular mechanisms mediating hypoxia-induced adaptations in the fetus are poorly understood. We tested the hypothesis that hypoxia up-regulates endothelial nitric oxide synthase (NOS3, type III) protein expression in fetal hearts similar to that observed in adult hearts as a cardioprotective adaptation. This study investigates the effect of chronic hypoxia on NOS3 protein expression in hearts and carotid arteries of fetal guinea pigs exposed to normoxia or intrauterine hypoxia. METHODS Time-mated pregnant guinea pigs (term = 65 days) were housed in either normoxic room air (NMX) or exposed to 12% O(2) (hypoxia; HPX) for 14 or 28 days of duration. At near term ( approximately 60 days of gestation), pregnant mothers were anesthetized and fetal guinea pig hearts and carotid arteries were excised from NMX and HPX animals and frozen until ready for study. In addition, hearts were also excised from anesthetized adult nonpregnant female guinea pigs exposed to either NMX or HPX for 14 days. NOS3 protein was extracted from all tissues and quantified using Western blot analysis. Fetal heart samples were also prepared for localization of NOS3 protein using immunohistochemistry. RESULTS Chronic hypoxia increased both maternal and fetal hematocrit after 28 days of duration. HPX decreased NOS3 protein levels in fetal guinea pig hearts by 29% after 28 days compared to NMX controls. In contrast, HPX increased both NOS3 protein levels in adult hearts by 62% and fetal carotid arteries by fourfold after 14 days of exposure compared to their respective NMX controls. Positive immunostaining of NOS3 protein of fetal hearts was localized in both cardiomyocytes and endothelial cells. CONCLUSION Contrary to our hypothesis, the hypoxia-induced decrease in fetal guinea pig heart NOS3 protein contrasts to the protein levels measured in either adult hearts or fetal carotid arteries. These results suggest that the NOS protein expression is altered differently by hypoxia in fetal and adult hearts and in a peripheral fetal artery exposed to the same level of hypoxia. Thus, the functional role of NO in the fetal heart during hypoxia may differ from that of the adult.
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Affiliation(s)
- Loren P Thompson
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore 21201, USA.
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