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Stotts C, Corrales-Medina VF, Rayner KJ. Pneumonia-Induced Inflammation, Resolution and Cardiovascular Disease: Causes, Consequences and Clinical Opportunities. Circ Res 2023; 132:751-774. [PMID: 36927184 DOI: 10.1161/circresaha.122.321636] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Pneumonia is inflammation in the lungs, which is usually caused by an infection. The symptoms of pneumonia can vary from mild to life-threatening, where severe illness is often observed in vulnerable populations like children, older adults, and those with preexisting health conditions. Vaccines have greatly reduced the burden of some of the most common causes of pneumonia, and the use of antimicrobials has greatly improved the survival to this infection. However, pneumonia survivors do not return to their preinfection health trajectories but instead experience an accelerated health decline with an increased risk of cardiovascular disease. The mechanisms of this association are not well understood, but a persistent dysregulated inflammatory response post-pneumonia appears to play a central role. It is proposed that the inflammatory response during pneumonia is left unregulated and exacerbates atherosclerotic vascular disease, which ultimately leads to adverse cardiac events such as myocardial infarction. For this reason, there is a need to better understand the inflammatory cross talk between the lungs and the heart during and after pneumonia to develop therapeutics that focus on preventing pneumonia-associated cardiovascular events. This review will provide an overview of the known mechanisms of inflammation triggered during pneumonia and their relevance to the increased cardiovascular risk that follows this infection. We will also discuss opportunities for new clinical approaches leveraging strategies to promote inflammatory resolution pathways as a novel therapeutic target to reduce the risk of cardiac events post-pneumonia.
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Affiliation(s)
- Cameron Stotts
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada (C.S., K.J.R).,Centre for Infection, Immunity, and Inflammation, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada (C.S., V.F.C.-M.).,University of Ottawa Heart Institute, Ottawa, ON, Canada (C.S., K.J.R)
| | - Vicente F Corrales-Medina
- Centre for Infection, Immunity, and Inflammation, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada (C.S., V.F.C.-M.).,Department of Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada (V.F.C-M).,Ottawa Hospital Research Institute, Ottawa, ON, Canada (V.F.C.-M)
| | - Katey J Rayner
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada (C.S., K.J.R).,University of Ottawa Heart Institute, Ottawa, ON, Canada (C.S., K.J.R)
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2
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Li C, Zhu Z, Yuan H, Zhong P, Peng Q, Dong X, Huang M, Liu B, Ren Y, Kuang Y, Zeng X, Yu H, Yang X. Improved Retinal Microcirculation After Cardiac Surgery in Patients With Congenital Heart Disease. Front Cardiovasc Med 2021; 8:712308. [PMID: 34532349 PMCID: PMC8438171 DOI: 10.3389/fcvm.2021.712308] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 08/06/2021] [Indexed: 12/16/2022] Open
Abstract
Background: Microcirculatory changes in congenital heart disease (CHD) patients undergoing cardiac surgery are not fully understood. We aimed to investigate the changes of retinal microcirculation in CHD patients after cardiac surgery by optical coherence tomography angiography (OCTA) and explore the association between retinal microcirculation and surgical outcome. Methods: This prospective observational study consisted of 71 CHD patients aged ≥6 years undergoing cardiac surgery including 19 cyanotic CHD (CCHD) and 52 acyanotic CHD (ACHD). Optical coherence tomography angiography (OCTA) was used to measure vessel density (VD) and capillary density (CD) of radial peripapillary capillary (RPC) and peripapillary, VD of superficial capillary plexus (SCP) and deep capillary plexus (DCP), thickness of retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) preoperatively and 1 month postoperatively. Transthoracic echocardiography was conducted to measure macrocirculation. Results: In CCHD patients, VD and CD of RPC and peripapillary increased postoperatively (all P < 0.05). In ACHD patients, VD of peripapillary, CD of RPC and peripapillary, and RNFL thickness increased postoperatively (all P < 0.05). VD of SCP and DCP, and GCC thickness did not change significantly in CHD patients after surgery. Lower preoperative retinal microvascular density was associated with longer cardiopulmonary bypass (CPB) time and postoperative length of stay (PLOS). No correlation was found between microcirculatory and macrohemodynamic parameters (all P > 0.05). Conclusions: Improved retinal microcirculation was observed after congenital cardiac surgery and impaired preoperative retinal microvasculature was associated with prolonged CPB time and PLOS, which might provide potential information about the outcome of congenital cardiac surgery.
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Affiliation(s)
- Cong Li
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,School of Medicine, South China University of Technology, Guangzhou, China
| | - Zhuoting Zhu
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Haiyun Yuan
- Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Department of Cardiovascular Surgery, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Pingting Zhong
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Medical College, Shantou University, Shantou, China
| | - Qingsheng Peng
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Medical College, Shantou University, Shantou, China
| | - Xinran Dong
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Manqing Huang
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Baoyi Liu
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Yun Ren
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Medical College, Shantou University, Shantou, China
| | - Yu Kuang
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Xiaomin Zeng
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Honghua Yu
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Xiaohong Yang
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
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3
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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: 53] [Impact Index Per Article: 17.7] [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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4
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Li C, Zhong P, Yuan H, Dong X, Peng Q, Huang M, Wu Q, Liu B, Xu M, Kuang Y, Zeng X, Xiao Y, Fang Y, Yu H, Yang X. Retinal microvasculature impairment in patients with congenital heart disease investigated by optical coherence tomography angiography. Clin Exp Ophthalmol 2020; 48:1219-1228. [PMID: 32860305 PMCID: PMC7756805 DOI: 10.1111/ceo.13846] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/12/2020] [Accepted: 08/18/2020] [Indexed: 12/11/2022]
Abstract
Importance A high prevalence of retinal abnormalities have been reported in congenital heart disease (CHD), but quantitative analysis of retinal vasculature is scarce. Optical coherence tomography angiography (OCTA) is a noninvasive method to quantitatively assess the retinal microvasculature. Background To investigate the retinal microvasculature changes in CHD patients by using OCTA. Design Cross‐sectional study. Participants A total of 158 participants including 57 cyanotic CHD (CCHD) patients, 60 acyanotic CHD (ACHD) patients and 41 control subjects were included. Methods All participants underwent a comprehensive ophthalmologic examination, including refraction measurement, intraocular pressure measurement and OCTA. Main Outcome Measures Vessel density (VD) was measured within the radial peripapillary capillary (RPC), superficial capillary plexus (SCP) and deep capillary plexus (DCP) of the macula. Results CCHD patients had significantly lower VD in the RPC, SCP and DCP (all P < .01) compared to control subjects, and significantly lower VD in the RPC and DCP (both P < .05) compared to ACHD patients. Besides, among the CHD group, VD in the RPC was positively correlated with oxygen saturation (whole image, ρ = 0.45; peripapillary, ρ = 0.48) and negatively correlated with haematocrit (whole image, ρ = 0.55; peripapillary, ρ = 0.55) (all P < .001). Conclusions and Relevance Retinal VD might be a surrogate to reflect the effect of chronic systemic hypoxemia in CHD patients. OCTA could be a convenient and noninvasive tool to evaluate the retinal structure and function in CHD patients.
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Affiliation(s)
- Cong Li
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, School of Medicine, South China University of Technology, Guangzhou, China
| | - Pingting Zhong
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, School of Medicine, South China University of Technology, Guangzhou, China.,Medical College, Shantou University, Shantou, China
| | - Haiyun Yuan
- Department of Cardiovascular Surgery, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Xinran Dong
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, School of Medicine, South China University of Technology, Guangzhou, China
| | - Qingsheng Peng
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, School of Medicine, South China University of Technology, Guangzhou, China.,Medical College, Shantou University, Shantou, China
| | - Manqing Huang
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, School of Medicine, South China University of Technology, Guangzhou, China
| | - Qiaowei Wu
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, School of Medicine, South China University of Technology, Guangzhou, China.,The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Baoyi Liu
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, School of Medicine, South China University of Technology, Guangzhou, China.,The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Minghui Xu
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, School of Medicine, South China University of Technology, Guangzhou, China
| | - Yu Kuang
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, School of Medicine, South China University of Technology, Guangzhou, China
| | - Xiaomin Zeng
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, School of Medicine, South China University of Technology, Guangzhou, China.,The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Yu Xiao
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, School of Medicine, South China University of Technology, Guangzhou, China.,The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Ying Fang
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, School of Medicine, South China University of Technology, Guangzhou, China
| | - Honghua Yu
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, School of Medicine, South China University of Technology, Guangzhou, China
| | - Xiaohong Yang
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, School of Medicine, South China University of Technology, Guangzhou, China
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5
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Chatterjee S, Tao JQ, Johncola A, Guo W, Caporale A, Langham MC, Wehrli FW. Acute exposure to e-cigarettes causes inflammation and pulmonary endothelial oxidative stress in nonsmoking, healthy young subjects. Am J Physiol Lung Cell Mol Physiol 2019; 317:L155-L166. [PMID: 31042077 DOI: 10.1152/ajplung.00110.2019] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The effects of e-cigarette (e-cig) aerosol inhalation by nonsmokers have not been examined to date. The present study was designed to evaluate the acute response to aerosol inhalation of non-nicotinized e-cigarettes in terms of oxidative stress and indices of endothelial activation in human pulmonary microvascular endothelial cells (HPMVEC). Ten smoking-naïve healthy subjects (mean age ± SD = 28.7 ± 5.5 yr) were subjected to an e-cig challenge, following which their serum was monitored for markers of inflammation [C-reactive protein (CRP) and soluble intercellular adhesion molecule (sICAM)] and nitric oxide metabolites (NOx). The oxidative stress and inflammation burden of the circulating serum on the vascular network was also assessed by measuring reactive oxygen species (ROS) production and induction of ICAM-1 expression on HPMVEC. Our results show that serum indices of oxidative stress and inflammation increased significantly (P < 0.05 as compared with baseline), reaching a peak at approximately 1-2 h post-e-cig aerosol inhalation and returning to baseline levels at 6 h. The circulatory burden of the serum (ICAM-1 and ROS) increased significantly at 2 h and returned to baseline values 6 h post-e-cig challenge. ROS production by HPMVEC was found to occur via activation of the NADPH oxidase 2 (NOX2) pathways. These findings suggest that even in the absence of nicotine, acute e-cig aerosol inhalation leads to a transient increase in oxidative stress and inflammation. This can adversely affect the vascular endothelial network by promoting oxidative stress and immune cell adhesion. Thus e-cig inhalation has the potential to drive the onset of vascular pathologies.
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Affiliation(s)
- Shampa Chatterjee
- Institute for Environmental Medicine and Department of Physiology, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania
| | - Jian-Qin Tao
- Institute for Environmental Medicine and Department of Physiology, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania
| | - Alyssa Johncola
- Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania Health System , Philadelphia, Pennsylvania
| | - Wensheng Guo
- Department of Biostatistics and Epidemiology, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania
| | - Alessandra Caporale
- Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania Health System , Philadelphia, Pennsylvania
| | - Michael C Langham
- Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania Health System , Philadelphia, Pennsylvania
| | - Felix W Wehrli
- Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania Health System , Philadelphia, Pennsylvania
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6
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Keeley TP, Siow RCM, Jacob R, Mann GE. A PP2A-mediated feedback mechanism controls Ca 2+-dependent NO synthesis under physiological oxygen. FASEB J 2017; 31:5172-5183. [PMID: 28760745 PMCID: PMC5690389 DOI: 10.1096/fj.201700211r] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 07/17/2017] [Indexed: 12/20/2022]
Abstract
Intracellular O2 is a key regulator of NO signaling, yet most in vitro studies are conducted in atmospheric O2 levels, hyperoxic with respect to the physiologic milieu. We investigated NO signaling in endothelial cells cultured in physiologic (5%) O2 and stimulated with histamine or shear stress. Culture of cells in 5% O2 (>5 d) decreased histamine- but not shear stress–stimulated endothelial (e)NOS activity. Unlike cells adapted to a hypoxic environment (1% O2), those cultured in 5% O2 still mobilized sufficient Ca2+ to activate AMPK. Enhanced expression and membrane targeting of PP2A-C was observed in 5% O2, resulting in greater interaction with eNOS in response to histamine. Moreover, increased dephosphorylation of eNOS in 5% O2 was Ca2+-sensitive and reversed by okadaic acid or PP2A-C siRNA. The present findings establish that Ca2+ mobilization stimulates both NO synthesis and PP2A-mediated eNOS dephosphorylation, thus constituting a novel negative feedback mechanism regulating eNOS activity not present in response to shear stress. This, coupled with enhanced NO bioavailability, underpins differences in NO signaling induced by inflammatory and physiologic stimuli that are apparent only in physiologic O2 levels. Furthermore, an explicit delineation between physiologic normoxia and genuine hypoxia is defined here, with implications for our understanding of pathophysiological hypoxia.—Keeley, T. P., Siow, R. C. M., Jacob, R., Mann, G. E. A PP2A-mediated feedback mechanism controls Ca2+-dependent NO synthesis under physiological oxygen.
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Affiliation(s)
- Thomas P Keeley
- Cardiovascular Division, King's British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Richard C M Siow
- Cardiovascular Division, King's British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Ron Jacob
- Cardiovascular Division, King's British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Giovanni E Mann
- Cardiovascular Division, King's British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
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7
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Núñez-Gómez E, Pericacho M, Ollauri-Ibáñez C, Bernabéu C, López-Novoa JM. The role of endoglin in post-ischemic revascularization. Angiogenesis 2016; 20:1-24. [PMID: 27943030 DOI: 10.1007/s10456-016-9535-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 11/29/2016] [Indexed: 12/12/2022]
Abstract
Following arterial occlusion, blood vessels respond by forming a new network of functional capillaries (angiogenesis), by reorganizing preexisting capillaries through the recruitment of smooth muscle cells to generate new arteries (arteriogenesis) and by growing and remodeling preexisting collateral arterioles into physiologically relevant arteries (collateral development). All these processes result in the recovery of organ perfusion. The importance of endoglin in post-occlusion reperfusion is sustained by several observations: (1) endoglin expression is increased in vessels showing active angiogenesis/remodeling; (2) genetic endoglin haploinsufficiency in humans causes deficient angiogenesis; and (3) the reduction of endoglin expression by gene disruption or the administration of endoglin-neutralizing antibodies reduces angiogenesis and revascularization. However, the precise role of endoglin in the several processes associated with revascularization has not been completely elucidated and, in some cases, the function ascribed to endoglin by different authors is controversial. The purpose of this review is to organize in a critical way the information available for the role of endoglin in several phenomena (angiogenesis, arteriogenesis and collateral development) associated with post-ischemic revascularization.
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Affiliation(s)
- Elena Núñez-Gómez
- Renal and Cardiovascular Research Unit, Department of Physiology and Pharmacology, University of Salamanca, Salamanca, Spain.,Biomedical Research Institute of Salamanca (IBSAL), Salamanca, Spain
| | - Miguel Pericacho
- Renal and Cardiovascular Research Unit, Department of Physiology and Pharmacology, University of Salamanca, Salamanca, Spain.,Biomedical Research Institute of Salamanca (IBSAL), Salamanca, Spain
| | - Claudia Ollauri-Ibáñez
- Renal and Cardiovascular Research Unit, Department of Physiology and Pharmacology, University of Salamanca, Salamanca, Spain.,Biomedical Research Institute of Salamanca (IBSAL), Salamanca, Spain
| | - Carmelo Bernabéu
- Centro de Investigaciones Biológicas, Spanish National Research Council (CIB, CSIC), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - José M López-Novoa
- Renal and Cardiovascular Research Unit, Department of Physiology and Pharmacology, University of Salamanca, Salamanca, Spain. .,Biomedical Research Institute of Salamanca (IBSAL), Salamanca, Spain.
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8
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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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9
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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: 38] [Impact Index Per Article: 4.8] [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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11
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Gupta RK, Himashree G, Singh K, Soree P, Desiraju K, Agrawal A, Ghosh D, Dass D, Reddy PK, Panjwani U, Singh SB. Elevated pulmonary artery pressure and brain natriuretic peptide in high altitude pulmonary edema susceptible non-mountaineers. Sci Rep 2016; 6:21357. [PMID: 26892302 PMCID: PMC4759542 DOI: 10.1038/srep21357] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 01/13/2016] [Indexed: 02/04/2023] Open
Abstract
Exaggerated pulmonary pressor response to hypoxia is a pathgonomic feature observed in high altitude pulmonary edema (HAPE) susceptible mountaineers. It was investigated whether measurement of basal pulmonary artery pressure (Ppa) and brain natriuretic peptide (BNP) could improve identification of HAPE susceptible subjects in a non-mountaineer population. We studied BNP levels, baseline hemodynamics and the response to hypoxia (FIo2 = 0.12 for 30 min duration at sea level) in 11 HAPE resistant (no past history of HAPE, Control) and 11 HAPE susceptible (past history of HAPE, HAPE-S) subjects. Baseline Ppa (19.31 ± 3.63 vs 15.68 ± 2.79 mm Hg, p < 0.05) and plasma BNP levels (52.39 ± 32.9 vs 15.05 ± 9.6 pg/ml, p < 0.05) were high and stroke volume was less (p < 0.05) in HAPE-S subjects compared to control. Acute hypoxia produced an exaggerated increase in heart rate (p < 0.05), mean arterial pressure (p < 0.05) and Ppa (28.2 ± 5.8 vs 19.33 ± 3.74 mm Hg, p < 0.05) and fall in peripheral oxygen saturation (p < 0.05) in HAPE-S compared to control. Receiver operating characteristic (ROC) curves showed that Ppa response to acute hypoxia was the best variable to identify HAPE susceptibility (AUC 0.92) but BNP levels provided comparable information (AUC 0.85). BNP levels are easy to determine and may represent an important marker for the determination of HAPE susceptibility.
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Affiliation(s)
- Rajinder K. Gupta
- Defence Institute of Physiology and Allied Sciences. Timarpur, Delhi-110054, India
| | - G. Himashree
- Defence Institute of Physiology and Allied Sciences. Timarpur, Delhi-110054, India
| | - Krishan Singh
- Defence Institute of Physiology and Allied Sciences. Timarpur, Delhi-110054, India
| | - Poonam Soree
- Defence Institute of Physiology and Allied Sciences. Timarpur, Delhi-110054, India
| | - Koundinya Desiraju
- CSIR Institute of Genomics and Integrated Biology, Mall Road, Delhi 110007, India
| | - Anurag Agrawal
- CSIR Institute of Genomics and Integrated Biology, Mall Road, Delhi 110007, India
| | - Dishari Ghosh
- Defence Institute of Physiology and Allied Sciences. Timarpur, Delhi-110054, India
| | - Deepak Dass
- Defence Institute of Physiology and Allied Sciences. Timarpur, Delhi-110054, India
| | - Prassana K. Reddy
- Defence Institute of Physiology and Allied Sciences. Timarpur, Delhi-110054, India
| | - Usha Panjwani
- Defence Institute of Physiology and Allied Sciences. Timarpur, Delhi-110054, India
| | - Shashi Bala Singh
- Defence Institute of Physiology and Allied Sciences. Timarpur, Delhi-110054, India
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Rat aorta as a pharmacological tool for in vitro and in vivo studies. Life Sci 2016; 145:190-204. [DOI: 10.1016/j.lfs.2015.12.043] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Revised: 11/26/2015] [Accepted: 12/24/2015] [Indexed: 11/24/2022]
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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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Abstract
INTRODUCTION Cyanotic congenital heart disease is associated with functional limitation and vascular events. The nature and extent of endothelial dysfunction in cyanotic adults is poorly understood. We sought to characterise endothelial function in this setting. METHODS A total of fourteen adults with cyanotic congenital heart disease (40±3 years) together with age- and sex-matched healthy controls underwent assessment of nitric oxide-dependent vascular responses, including flow-mediated dilatation of the brachial artery and dynamic vessel analysis of the retina in response to flickering light. Plasma levels of the endothelium-derived vasoconstrictor endothelin-1 and the nitric oxide antagonist, asymmetric dimethylarginine, were measured. Circulating endothelial progenitor cells were assessed by flow cytometry. RESULTS Flow-mediated dilatation was significantly lower in cyanosed adults than controls (4.0±0.8 versus 7.2±1.0%, p=0.019, n=11 per group). Retinal arterial and venous dilatory responses were also impaired (2.9±0.8 versus 5.0±0.6%, p=0.05 and 3.4±0.3 versus 5.2±0.7%, p=0.04, n=13). Serum levels of endothelin-1 and asymmetric dimethylarginine were higher in cyanosed adults (3.0±0.6 versus 1.1±0.1 pg/ml, p=0.004 and 0.68±0.05 versus 0.52±0.02 μmol/L, p=0.03, n=11). Endothelial progenitor cells (CD34+CD45dimCD133+KDR+) were reduced in those with chronic cyanosis (17±4 versus 40±6 per million white blood cells, p=0.005, n=11). CONCLUSIONS Endothelial function is impaired in the systemic arteries and retinal vessels in adults with cyanotic congenital heart disease, suggesting a widespread endotheliopathy. Diminished numbers of endothelial progenitor cells might potentially contribute to these observations.
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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: 45] [Impact Index Per Article: 4.5] [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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Wang B, Yan B, Song D, Ye X, Liu SF. Chronic intermittent hypoxia down-regulates endothelial nitric oxide synthase expression by an NF-κB-dependent mechanism. Sleep Med 2012; 14:165-71. [PMID: 23266106 DOI: 10.1016/j.sleep.2012.10.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Revised: 10/03/2012] [Accepted: 10/28/2012] [Indexed: 10/27/2022]
Abstract
OBJECTIVES Patients with obstructive sleep apnea have an impaired endothelium-dependent vasodilator response. The mechanisms underlying this impairment remain unclear. We tested the hypothesis that chronic intermittent hypoxia (CIH) impairs endothelium-dependent vasodilatation by NF-κB-mediated down-regulation of endothelial nitric oxide synthase (eNOS) expression. METHODS Wild type (WT) mice and mice deficient in NF-κB p50 or TNF-α gene were exposed to sham or CIH. Aortic NF-κB activity and aortic expression of TNF-α were determined. Aortic and mesenteric artery levels of eNOS expression were examined and their correlation to endothelium-dependent vasodilator response in vitro and vasodepressor response in vivo were analyzed. RESULTS WT mice exposed to CIH for five to eight weeks showed significantly reduced eNOS protein expression in aortas and mesenteric arteries, associated with significantly blunted vasodilator and vasodepressor responses to acetylcholine, but not to sodium nitroprusside. CIH activated NF-κB, which preceded TNF-α up-regulation and eNOS down-regulation. NF-κB p50 gene deletion blocked NF-κB activation, inhibited TNF-α expression, prevented eNOS down-regulation and reversed the impaired endothelium-dependent vasodepressor response induced by CIH. TNF-α knockout prevented CIH-induced eNOS down-regulation and restored the endothelium-dependent vasodepressor response. CONCLUSIONS CIH exposure impairs endothelium-dependent vasodilator mechanism by stimulating NF-κB-mediated TNF-α generation, which in turn, down-regulates eNOS expression, resulting in an impaired endothelium-dependent vasodilatation.
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Affiliation(s)
- Baoshan Wang
- Department of Otolaryngology and Head and Neck Surgery, The First Hospital of Hebei Medical University, Shijiazhuang, China.
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Peng JF, Ling Y, Gou WY, Zhang H, Wu CX. Identification of chicken eNOS gene and differential expression in highland versus lowland chicken breeds. Poult Sci 2012; 91:2275-81. [PMID: 22912463 DOI: 10.3382/ps.2012-02197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Nitric oxide (NO), an endothelium-derived relaxing factor, is synthesized from l-arginine by endothelial nitric oxide synthase (eNOS) in the endothelium. The objective of the present study was to preliminarily illuminate the expression of the eNOS gene in hypoxic adaptation of chicken embryonic development. The eNOS expression profiles between the Tibet and Shouguang chickens incubated under both normoxic and hypoxic conditions were detected by TaqMan real-time PCR. In this study, the chicken eNOS gene was found by both in silico cloning and RACE approaches. From the eNOS gene, we obtained a 3,310-bp mRNA sequence and a 10,666-bp DNA sequence and discovered that it was located on chicken chromosome 2 and had 7 unique transcripts. eNOS mRNA was detected in abundant amounts in some chick embryo organs (i.e., heart, liver, chorio-allantoic membrane, and lung), and expressed stably with the lowest levels in the brain. We observed that when exposed to hypoxia (13% O(2)) different embryo organ tissues had various sensitivities to hypoxia as determined by their eNOS expression profiles. Compared with the Shouguang chicken, the eNOS expression in the Tibet chicken was higher in the lung and liver, lower in the heart, and similar in the brain. In chorio-allantoic membranes, eNOS expression was higher in the Shouguang chicken than the Tibet chicken under hypoxic conditions, but not markedly different under normoxic conditions. The differences of eNOS expression between the 2 breeds may be relative to the hypoxic adaptation ability in Tibet chickens during embryonic development. This work will provide reference for future studies on the role of eNOS in hypoxic adaptation and response.
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Affiliation(s)
- J F Peng
- National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
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Komniski MS, Yakushev S, Bogdanov N, Gassmann M, Bogdanova A. Interventricular heterogeneity in rat heart responses to hypoxia: the tuning of glucose metabolism, ion gradients, and function. Am J Physiol Heart Circ Physiol 2011; 300:H1645-52. [PMID: 21398597 DOI: 10.1152/ajpheart.00220.2010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The matching of energy supply and demand under hypoxic conditions is critical for sustaining myocardial function. Numerous reports indicate that basal energy requirements and ion handling may differ between the ventricles. We hypothesized that ventricular response to hypoxia shows interventricular differences caused by the heterogeneity in glucose metabolism and expression and activity of ion transporters. Thus we assessed glucose utilization rate, ATP, sodium and potassium concentrations, Na, K-ATPase activity, and tissue reduced:oxidized glutathione (GSH/GSSG) content in the right and left ventricles before and after the exposure of either the whole animals or isolated blood-perfused hearts to hypoxia. The hypoxia-induced boost in glucose utilization was more pronounced in the left ventricle compared with the right one. ATP levels in the right ventricle of hypoxic heart were lower than those in the left ventricle. Left ventricular sodium content was higher, and hydrolytic Na, K-ATPase activity was reduced compared with the right ventricle. Administration of the Na, K-ATPase blocker ouabain caused rapid increase in the right ventricular Na(+) and elimination of the interventricular Na(+) gradients. Exposure of the hearts to hypoxia made the interventricular heterogeneity in the Na(+) distribution even more pronounced. Furthermore, systemic hypoxia caused oxidative stress that was more pronounced in the right ventricle as revealed by GSH/GSSG ratios. On the basis of these findings, we suggest that the right ventricle is more prone to hypoxic damage, as it is less efficient in recruiting glucose as an alternative fuel and is particularly dependent on the efficient Na, K-ATPase function.
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Affiliation(s)
- Milena Segato Komniski
- Institute of Veterinary Physiology, Univ. of Zurich, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
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Büchner NJ, Quack I, Woznowski M, Stähle C, Wenzel U, Rump LC. Microvascular endothelial dysfunction in obstructive sleep apnea is caused by oxidative stress and improved by continuous positive airway pressure therapy. ACTA ACUST UNITED AC 2011; 82:409-17. [PMID: 21311167 DOI: 10.1159/000323266] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Accepted: 11/29/2010] [Indexed: 11/19/2022]
Abstract
BACKGROUND Endothelial dysfunction has recently been demonstrated in obstructive sleep apnea (OSA), but the underlying mechanisms are not entirely understood. Oxidative stress is a typical feature of OSA. OBJECTIVES We investigated the influence of oxidative stress and continuous positive airway pressure (CPAP) on microvascular endothelial function in OSA. METHODS Endothelial function of forearm resistance vessels was assessed by strain gauge venous occlusion plethysmography after intra-arterial infusion of the endothelium-independent vasodilator sodium nitroprusside (1.6, 3.2, and 4.0 μg/min) and the endothelium-dependent vasodilator acetylcholine (Ach, 15, 30 and 40 μg/min) in patients with (n = 11) and without (n = 8) OSA (apnea-hypopnea index ≥15/h). These measurements have been repeated after local intra-arterial infusion of the antioxidant vitamin C (25 μg/min). Furthermore, 6 patients have been reevaluated after 6 months of OSA treatment. RESULTS Patients with OSA demonstrated impaired endothelial function compared to those without OSA. Thus, related to baseline flow, the increase in forearm blood flow induced by Ach was blunted in patients with OSA (148.7 ± 29.7% in OSA vs. 233.6 ± 45.7% in controls, p = 0.001). This difference, however, was abolished by co-infusion of vitamin C. Endothelial function markedly improved following treatment in 5 of 6 OSA patients. CONCLUSIONS This study strongly suggests that microvascular endothelial function is affected by OSA predominantly through increased oxidative stress, and treatment of OSA may improve endothelial function mainly by reducing oxidative stress. The role of oxidative stress-induced endothelial dysfunction as a potential promoter of atherosclerosis and an increased cardiovascular risk in patients with OSA should be investigated in further controlled studies.
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Affiliation(s)
- Nikolaus J Büchner
- Department of Internal Medicine I, Marienhospital Herne, Ruhr-University Bochum, Herne, Germany
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20
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Jerkic M, Peter M, Ardelean D, Fine M, Konerding MA, Letarte M. Dextran sulfate sodium leads to chronic colitis and pathological angiogenesis in Endoglin heterozygous mice. Inflamm Bowel Dis 2010; 16:1859-70. [PMID: 20848471 PMCID: PMC2959118 DOI: 10.1002/ibd.21288] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Pathological angiogenesis is an intrinsic component of chronic intestinal inflammation, which results in remodeling and expansion of the gut microvascular bed. Endoglin is essential for endothelial cell function and physiological angiogenesis. In this study we investigated its potential role in the regulation of inflammation by testing the response of Endoglin heterozygous (Eng(+/-)) mice to experimental colitis. METHODS C57BL/6 Eng(+/-) and littermate control mice drank water supplemented with 3% dextran sulfate sodium (DSS) for 5 days and were monitored for up to 26 days for clinical signs of colitis. Inflammation, crypt damage, and angiogenic index were scored on histological sections of distal colon. Levels of the vascular endothelial growth factor (VEGF) and angiopoietins were measured by real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and/or Western blots. Vascular permeability was assessed using Evans Blue. RESULTS Eng(+/-) and control mice developed acute colitis, which peaked at day 9. While control mice recovered by days 19-26, Eng(+/-) mice progressed to chronic colitis and showed numerous vascular protrusions penetrating into the serosa of the inflamed distal colon. Prior to DSS induction, VEGF levels and vascular permeability were higher in the distal colon of Eng(+/-) mice, while angiopoietin 1 and 2 levels were unchanged. In the chronic phase of colitis, VEGF levels were increased in both groups of mice and remained significantly higher in the Eng(+/-) mice. CONCLUSIONS Higher VEGF levels and increased vascular permeability in the distal colon may predispose Eng(+/-) mice to progress to chronic and persistent bowel inflammation, associated with pathological angiogenesis.
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Affiliation(s)
- Mirjana Jerkic
- Molecular Structure and Function Program, Hospital for Sick Children,The Heart and Stroke Foundation Richard Lewar Centre of Excellence, University of Toronto
| | - Madonna Peter
- Molecular Structure and Function Program, Hospital for Sick Children,Department of Immunology, University of Toronto
| | - Daniela Ardelean
- Molecular Structure and Function Program, Hospital for Sick Children,Division of Pediatric Rheumatology, Hospital for Sick Children
| | | | | | - Michelle Letarte
- Molecular Structure and Function Program, Hospital for Sick Children,The Heart and Stroke Foundation Richard Lewar Centre of Excellence, University of Toronto,Department of Immunology, University of Toronto
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Abstract
Nitric oxide (NO) is a structurally simple, highly versatile molecule that was originally discovered over 30 years ago as an endothelium-derived relaxing factor. In addition to its vasorelaxing effects, NO is now recognized as a key determinant of vascular health, exerting antiplatelet, antithrombotic, and anti-inflammatory properties within the vasculature. This short-lived molecule exerts its inhibitory effect on vascular smooth muscle cells and platelets largely through cyclic guanosine monophosphate-dependent mechanisms, resulting in a multitude of molecular effects by which platelet activation and aggregation are prevented. The biosynthesis of NO occurs via the catalytic activity of NO synthase, an oxidoreductase found in many cell types. NO insufficiency can be attributed to limited substrate/cofactor availability as well as interactions with reactive oxygen species. Impaired NO bioavailability represents the central feature of endothelial dysfunction, a common abnormality found in many vascular diseases. In this review, we present an overview of NO synthesis and biochemistry, discuss the mechanisms of action of NO in regulating platelet and endothelial function, and review the effects of vascular disease states on NO bioavailability.
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Affiliation(s)
- Richard C Jin
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
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Chronic cyanosis and vascular function: implications for patients with cyanotic congenital heart disease. Cardiol Young 2010; 20:242-53. [PMID: 20416139 DOI: 10.1017/s1047951110000466] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In patients with cyanotic congenital heart disease, chronic hypoxaemia leads to important changes in blood vessel function and structure. Some of these alterations are maladaptive and probably contribute to impaired cardiopulmonary performance and an increased incidence of thrombotic and embolic events. Recent evidence suggests that deranged endothelial function, a sequel of chronic cyanosis, could be an important factor in the pathogenesis of cyanosis-associated cardiovascular risk. In this article, we discuss the physiological and mechanical consequences of compensatory erythrocytosis and possible pathophysiological mechanisms of vascular dysfunction in chronic cyanosis.
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Tual-Chalot S, Guibert C, Muller B, Savineau JP, Andriantsitohaina R, Martinez MC. Circulating microparticles from pulmonary hypertensive rats induce endothelial dysfunction. Am J Respir Crit Care Med 2010; 182:261-8. [PMID: 20339146 DOI: 10.1164/rccm.200909-1347oc] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
RATIONALE Pulmonary arterial hypertension (PAH) is a severe disease characterized by an increase of pulmonary vascular resistance, which is accompanied by functional and structural changes in pulmonary arteries. Microparticles (MPs) have been described as biological vector of endothelial dysfunction in other pathologies. OBJECTIVES The purpose of this work was to characterize circulating MPs during hypoxic PAH and to study their effects on endothelial function. METHODS Male Wistar rats were exposed or not to chronic hypoxia, and normoxic or hypoxic MPs from blood were characterized by flow cytometry. Endothelial cells (ECs) from rat aorta or pulmonary arteries were incubated with MPs, and then expression and phosphorylation of enzymes involved in nitric oxide (NO) and reactive oxygen species productions were analyzed. Hypoxic MPs were injected into rats, and endothelium-dependent relaxation was assessed. MEASUREMENTS AND MAIN RESULTS Circulating levels of MPs from hypoxic rats were twofold higher than those present in normoxic rats. In vitro treatment of ECs with hypoxic MPs reduced NO production in aortas and pulmonary arteries by enhancing phosphorylation of endothelial NO synthase at the inhibitory site. Hypoxic MPs increased oxidative stress only in pulmonary ECs via xanthine oxidase and mitochondrial implication. In vivo injection of hypoxic MPs into rat impaired endothelium-dependent relaxation both in aorta and pulmonary arteries. CONCLUSIONS These data provide evidence that hypoxic circulating MPs induce endothelial dysfunction in rat aorta and pulmonary arteries by decreasing NO production. Moreover, MPs display tissue specificity with respect to increased oxidative stress, which occurs only in pulmonary ECs.
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Affiliation(s)
- Simon Tual-Chalot
- CNRS UMR 6214, Faculté de Médecine, Rue Haute de Reculée, Angers, F-49045 France
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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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Natarajan S, Heiss C, Yeghiazarians Y, Fineman JR, Teitel DF, Tacy TA. Peripheral arterial function in infants and young children with one-ventricle physiology and hypoxemia. Am J Cardiol 2009; 103:862-6. [PMID: 19268746 DOI: 10.1016/j.amjcard.2008.11.059] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Revised: 11/13/2008] [Accepted: 11/13/2008] [Indexed: 12/29/2022]
Abstract
Patients with 1-ventricle (1V) physiology may be at risk for peripheral arterial dysfunction at a young age. To determine whether infants and young children with 1V physiology and hypoxemia have peripheral arterial dysfunction before undergoing the Fontan operation, we measured (1) flow-mediated vasodilation (FMD) in the brachial artery, (2) serum levels of vasoactive mediators endothelin-1 (ET-1) and metabolites of nitric oxide, and (3) arterial stiffness with pulse-wave velocity (PWV) in the aorta. Eighteen patients with 1V physiology before the Fontan procedure and hypoxemia and 19 patients with normoxemia and 2-ventricle (2V) physiology were studied. Measurements were collected during cardiac catheterization. FMD in the brachial artery was the diameter gain after 4.5 minutes of forearm occlusion measured with high-resolution ultrasound and edge-detection software. Nitric oxide and ET-1 levels were measured in venous blood. PWV between the left carotid and femoral arteries was measured using pulse Doppler ultrasound. FMD was lower (2.4 +/- 3.7% vs 11.3 +/- 6%, p <0.0005) and ET-1 levels were higher (35.5 +/- 11.3% vs 24.1 +/- 9.7%, p = 0.003) in subjects with 1V physiology versus those with 2V physiology, respectively. There were no differences in nitric oxide levels or PWV. In conclusion, infants and young children with 1V physiology and hypoxemia have blunted FMD and higher ET-1 levels before undergoing the Fontan operation compared with normoxemic subjects with 2V physiology. A further understanding of pathophysiologic mechanisms underlying peripheral arterial dysfunction, including the roles of hypoxemia, low cardiac index, and ET-1, may lead to targeted therapies and improve the long-term survival of patients with 1V physiology.
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Hypoxia-induced regulation of nitric oxide synthase in cardiac endothelial cells and myocytes and the role of the PI3-K/PKB pathway. Mol Cell Biochem 2008; 321:23-35. [PMID: 18791856 DOI: 10.1007/s11010-008-9906-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Accepted: 08/19/2008] [Indexed: 01/26/2023]
Abstract
UNLABELLED The roles of endothelial nitric oxide synthase (eNOS), and its putative association with protein kinase B (PKB), and inducible nitric oxide synthase (iNOS) are not well characterized in hypoxic cardiac cells and there is a lack of studies that measure nitric oxide (NO) directly. OBJECTIVE To measure NO production in cardiomyocytes and cardiac microvascular endothelial cells (CMECs) under baseline and hypoxic conditions and to evaluate the expression, regulation and activation of eNOS, iNOS and PKB. The effect of PI3-K/PKB inhibition on NO production and eNOS expression/activation was also investigated. METHODS Adult rat cardiomyocytes and rat CMECs were made hypoxic by cell pelleting and low PO(2) incubation. Intracellular NO was measured by FACS analysis of DAF-2/DA fluorescence, and eNOS, iNOS and PKB were evaluated by Western blotting or flow cytometry. Upstream PKB inhibition was achieved with wortmannin. RESULTS (1) NO levels increased in both cell types after exposure to hypoxia. (2) In hypoxic CMECs, eNOS was upregulated and activated, no iNOS expression was observed and PKB was activated. (3) In myocytes, hypoxia did not affect eNOS expression, but increased its activation. Activated PKB also increased during hypoxia. FACS analysis showed increased iNOS in hypoxic myocytes. (4) Wortmannin resulted in decreased hypoxia-induced NO production and reduced activated eNOS levels. CONCLUSIONS Cardiomyocytes and CMECs show increased NO production during hypoxia. eNOS seems to be the main NOS isoform involved as source of the increased NO generation, although there may be a role for iNOS and other non-eNOS sources of NO in the hypoxic myocytes. Hypoxia-induced PKB and eNOS activation occurred simultaneously in both cell types, and the PI3-K/PKB pathway was associated with hypoxia-induced NO production via eNOS activation.
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Hunt BE, Tamisier R, Gilmartin GS, Curley M, Anand A, Weiss JW. Baroreflex responsiveness during ventilatory acclimatization in humans. Am J Physiol Heart Circ Physiol 2008; 295:H1794-801. [PMID: 18757487 DOI: 10.1152/ajpheart.131.2008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We tested the hypothesis that the decline in muscle sympathetic activity during and after 8 h of poikilocapnic hypoxia (Hx) was associated with a greater sympathetic baroreflex-mediated responsiveness. In 10 healthy men and women (n=2), we measured beat-to-beat blood pressure (Portapres), carotid artery distension (ultrasonography), heart period, and muscle sympathetic nerve activity (SNA; microneurography) during two baroreflex perturbations using the modified Oxford technique before, during, and after 8 h of hypoxia (84% arterial oxygen saturation). The integrated baroreflex response [change of SNA (DeltaSNA)/change of diastolic blood pressure (DeltaDBP)], mechanical (Deltadiastolic diameter/DeltaDBP), and neural (DeltaSNA/Deltadiastolic diameter) components were estimated at each time point. Sympathetic baroreflex responsiveness declined throughout the hypoxic exposure and further declined upon return to normoxia [pre-Hx, -8.3+/-1.2; 1-h Hx, -7.2+/-1.0; 7-h Hx, -4.9+/-1.0; and post-Hx: -4.1+/-0.9 arbitrary integrated units (AIU) x min(-1) x mmHg(-1); P<0.05 vs. previous time point for 1-h, 7-h, and post-Hx values]. This blunting of baroreflex-mediated efferent outflow was not due to a change in the mechanical transduction of arterial pressure into barosensory stretch. Rather, the neural component declined in a similar pattern to that of the integrated reflex response (pre-Hx, -2.70+/-0.53; 1-h Hx, -2.59+/-0.53; 7-h Hx, -1.60+/-0.34; and post-Hx, -1.34+/-0.27 AIU x min(-1) x microm(-1); P < 0.05 vs. pre-Hx for 7-h and post-Hx values). Thus it does not appear as if enhanced baroreflex function is primarily responsible for the reduced muscle SNA observed during intermediate duration hypoxia. However, the central transduction of baroreceptor afferent neural activity into efferent neural activity appears to be reduced during the initial stages of peripheral chemoreceptor acclimatization.
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Affiliation(s)
- Brian E Hunt
- Department of Kinesiology, School of Public Health and Health Sciences, University of Massachusetts, Amherst, Massachusetts, USA.
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Kao SJ, Liu DD, Su CF, Chen HI. Niacinamide abrogates the organ dysfunction and acute lung injury caused by endotoxin. J Cardiovasc Pharmacol 2007; 50:333-42. [PMID: 17878764 DOI: 10.1097/fjc.0b013e3180cbd18a] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Poly (ADP-ribose) synthabse (PARS) or polymerase (PARP) is a cytotoxic enzyme causing cellular damage. Niacinamide inhibits PARS or PARP. The present experiment tests the effects of niacinamide (NCA) on organ dysfunction and acute lung injury (ALI) following lipopolysaccharide (LPS). LPS was administered to anesthetized rats and to isolated rat lungs. In anesthetized rats, LPS caused systemic hypotension and increased biochemical factors, nitrate/nitrite (NOx), methyl guanidine (MG), tumor necrosis factoralpha (TNFalpha), and interleukin-1beta (IL-1beta). In isolated lungs, LPS increased lung weight (LW) to body weight ratio, LW gain, protein and dye tracer leakage, and capillary permeability. The insult also increased NOx, MG, TNFalpha, and IL-1beta in lung perfusate, while decreased adenosine triphosphate (ATP) content with an increase in PARP activity in lung tissue. Pathological examination revealed pulmonary edema with inflammatory cell infiltration. These changes were abrogated by posttreatment (30 min after LPS) with NCA. Following LPS, the inducible NO synthase (iNOS) mRNA expression was increased. NCA reduced the iNOS expression. Niacinamide exerts protective effects on the organ dysfunction and ALI caused by endotoxin. The mechanisms may be mediated through the inhibition on the PARP activity, iNOS expression and the subsequent suppression of NO, free radicals, and proinflammatory cytokines with restoration of ATP.
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Affiliation(s)
- Shang-Jyh Kao
- Division of Chest Medicine, Internal Medicine, Shin-Kong Wu-Ho-Su Memorial Hospital, School of Respiratory Therapy, Taipei Medical University, and College of Medicine, Fu-Jen University, Taipei, Taiwan
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Ray JB, Arab S, Deng Y, Liu P, Penn L, Courtman DW, Ward ME. Oxygen regulation of arterial smooth muscle cell proliferation and survival. Am J Physiol Heart Circ Physiol 2007; 294:H839-52. [PMID: 18055518 DOI: 10.1152/ajpheart.00587.2007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to determine if hypoxia elicits different proliferative and apoptotic responses in systemic arterial smooth muscle cells incubated under conditions that do or do not result in cellular ATP depletion and whether these effects are relevant to vascular remodeling in vivo. Gene expression profiling was used to identify potential regulatory pathways. In human aortic smooth muscle cells (HASMCs) incubated at 3% O(2), proliferation and progression through the G1/S interphase are enhanced. Incubation at 1% O(2) reduced proliferation, delayed G1/S transition, increased apoptotic cell death, and is associated with mitochondrial membrane depolarization and reduced cellular ATP levels. In aorta and mesenteric artery from rats exposed to hypoxia (10% O(2), 48 h), both proliferation and apoptosis are increased, as are medial nuclear density and smooth muscle cell content. Although nuclear levels of hypoxia-inducible factor 1-alpha (HIF-1alpha) are increased to a similar extent in HASMCs incubated at 1 and 3% O(2), expression of tumor protein p53, its transcriptional target p21, as well as their regulatory factors and downstream effectors, are differentially affected under these two conditions, suggesting that the bidirectional effects of hypoxia are mediated by this pathway. We conclude that hypoxia induces a state of enhanced cell turnover through increased rates of both smooth muscle cell proliferation and death. This confers the ability to remodel the vasculature in response to changing tissue metabolic needs while avoiding the accumulation of mutations that may lead to malignant transformation or the formation of abnormal vascular structures.
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Affiliation(s)
- Julie Basu Ray
- Institute of Medical Science, University of Toronto, St. Michael's Hospital, Ontario, Canada
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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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Ziebell BT, Galan HL, Anthony RV, Regnault TRH, Parker TA, Arroyo JA. Ontogeny of endothelial nitric oxide synthase mRNA in an ovine model of fetal and placental growth restriction. Am J Obstet Gynecol 2007; 197:420.e1-5. [PMID: 17904986 DOI: 10.1016/j.ajog.2007.07.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 06/20/2007] [Accepted: 07/16/2007] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To determine: 1) placental eNOS mRNA concentration across gestation in normal ovine pregnancy and in an ovine model of intrauterine growth restriction (IUGR), and 2) placental eNOS protein concentration in early ovine pregnancy. STUDY DESIGN A total of 24 sheep were studied with 12 ewes placed in hyperthermic (HT) conditions to induce IUGR and 12 were kept in control conditions. HT and control animals underwent euthanasia at 3 developmental time points (55, 95, & 130 days gestational age; dGA) in ovine placental & fetal development. RESULTS Compared to controls, HT pregnancies showed 1) no differences in fetal weights at 55 dGA and 95dGA with significant reductions at 130 dGA, 2) significantly smaller placentae at 95 and 130 dGA with a trend for a reduction at 55 dGA, 3) significant decreases in cotyledon eNOS mRNA at 95 and 130 dGA, 4) a significant increase in caruncle eNOS mRNA expression at 130 dGA, 5) significant increase in eNOS protein in the caruncle, but not in the cotyledon at 55 dGA. CONCLUSION Placental eNOS concentration is transcriptionally regulated at mid-gestation, while additional post-transcriptional regulation is also involved during early and late gestation in this model of placental and fetal growth restriction.
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Affiliation(s)
- Bradley T Ziebell
- Division of Perinatal Medicine, Department of Obstetrics & Gynecology, University of Colorado at Denver and Health Sciences Center, Denver, CO 80262, USA
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Fish JE, Matouk CC, Yeboah E, Bevan SC, Khan M, Patil K, Ohh M, Marsden PA. Hypoxia-inducible expression of a natural cis-antisense transcript inhibits endothelial nitric-oxide synthase. J Biol Chem 2007; 282:15652-66. [PMID: 17403686 DOI: 10.1074/jbc.m608318200] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The destabilization of endothelial nitric-oxide synthase (eNOS) mRNA in hypoxic endothelial cells may be important in the etiology of vascular diseases, such as pulmonary hypertension. Recently, an overlapping antisense transcript to eNOS/NOS3 was implicated in the post-transcriptional regulation of eNOS. We demonstrate here that expression of sONE, also known as eNOS antisense (NOS3AS) or autophagy 9-like 2 (APG9L2), is robustly induced by hypoxia or functional deficiency of von Hippel-Lindau protein. sONE is also up-regulated in the aortas of hypoxic rats. In hypoxic endothelial cells, sONE expression negatively correlates with eNOS expression. Blocking the hypoxic induction of sONE by RNA interference attenuates the fall in both eNOS RNA and protein. We provide evidence that the induction of sONE primarily involves transcript stabilization rather than increased transcriptional activity and is von Hippel-Lindaubut not hypoxia-inducible factor 2alpha-dependent. We also demonstrate that sONE transcripts are enriched in the nucleus of normoxic cells and that hypoxia promotes an increase in the level of cytoplasmic and polyribosome-associated, sONE mRNA. The finding that eNOS expression can be regulated by an overlapping cis-antisense transcript in a stimulus-dependent fashion provides evidence that sense/antisense interactions may play a previously unappreciated role in vascular disease pathogenesis.
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Affiliation(s)
- Jason E Fish
- Department of Medical Biophysics, St. Michael's Hospital, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Manukhina EB, Vanin AF, Markov KM, Malyshev IY. Formation and Role of Nitric Oxide Stores in Adaptation to Hypoxia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2006; 578:35-40. [PMID: 16927667 DOI: 10.1007/0-387-29540-2_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Eugenia B Manukhina
- Institute of General Pathology and Pathophysiology, Baltijskaya 8, Moscow 125315, Russia
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Quan A, Ward ME, Kulandavelu S, Adamson SL, Langille BL. Endothelium-independent flow-induced dilation in the mouse carotid artery. J Vasc Res 2006; 43:383-91. [PMID: 16837773 DOI: 10.1159/000094414] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2005] [Accepted: 05/08/2006] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND We investigated the locus of flow regulation of vascular tone in carotid arteries of C57 Bl/6 and eNOS(-/-) mice. METHODS Arterial segments (2-3 mm) were mounted in a perfusion myograph and preconstricted with 1 muM phenylephrine before monitoring flow-induced changes in lumen diameter. RESULTS Both control and eNOS(-/-) mice demonstrated flow-dependent relaxation. This response was not attenuated by the NO synthase antagonist L-NAME, the cyclooxygenase inhibitor indomethacin, the selective guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one (ODQ), the adenylate cyclase inhibitor Rp-8-Br-cAMPs, integrin-binding RGD peptides, or by removal of the endothelium. Hypoxia, a physiological stimulus known to alter endothelium-dependent flow regulation of vascular tone, also failed to attenuate the observed flow-mediated dilation. CONCLUSIONS These findings indicate the existence of a previously unidentified endothelium-independent mechanism of flow-induced dilation in the carotid artery. Further investigations to identify the mechanisms that underlie this response may provide novel therapeutic directions in the treatment of disorders characterized by abnormal flow regulation of vascular tone.
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MESH Headings
- Acetylcholine/pharmacology
- Animals
- Blood Flow Velocity
- Carotid Arteries/drug effects
- Carotid Arteries/enzymology
- Carotid Arteries/physiology
- Cyclooxygenase Inhibitors/pharmacology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/enzymology
- Endothelium, Vascular/physiology
- Guanylate Cyclase/antagonists & inhibitors
- Guanylate Cyclase/metabolism
- In Vitro Techniques
- Indomethacin/pharmacology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Muscle, Smooth, Vascular/physiology
- NG-Nitroarginine Methyl Ester/pharmacology
- Nitric Oxide Synthase Type II/antagonists & inhibitors
- Nitric Oxide Synthase Type II/genetics
- Nitric Oxide Synthase Type II/metabolism
- Nitric Oxide Synthase Type III
- Oxadiazoles/pharmacology
- Quinoxalines/pharmacology
- Vasodilation
- Vasodilator Agents/pharmacology
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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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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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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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Ward ME, Toporsian M, Scott JA, Teoh H, Govindaraju V, Quan A, Wener AD, Wang G, Bevan SC, Newton DC, Marsden PA. Hypoxia induces a functionally significant and translationally efficient neuronal NO synthase mRNA variant. J Clin Invest 2006; 115:3128-39. [PMID: 16276418 PMCID: PMC1265848 DOI: 10.1172/jci20806] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2003] [Accepted: 08/30/2005] [Indexed: 11/17/2022] Open
Abstract
We tested the hypothesis that induction of neuronal NO synthase (nNOS) impairs vascular smooth muscle contractility after hypoxia. nNOS protein was increased in aorta, mesenteric arterioles, pulmonary arteries, brain, and diaphragm from rats exposed to 8% O2 for 48 hours and in human aortic SMCs after hypoxic incubation (1% O2). Ca-dependent NO synthase activity was increased in endothelium-denuded aortic segments from hypoxia-exposed rats. N-nitro-L-arginine methyl ester enhanced the contractile responses of endothelium-denuded aortic rings and mesenteric arterioles from hypoxia-exposed but not normoxic rats (P < 0.05). The hypoxia-inducible mRNA transcript expressed by human cells was found to contain a novel 5'-untranslated region, consistent with activation of transcription in the genomic region contiguous with exon 2. Translational efficiency of this transcript is markedly increased compared with previously described human nNOS mRNAs. Transgenic mice possessing a lacZ reporter construct under control of these genomic sequences demonstrated expression of the construct after exposure to hypoxia (8% O2, 48 hours) in the aorta, mesenteric arterioles, renal papilla, and brain. These results reveal a novel human nNOS promoter that confers the ability to rapidly upregulate nNOS expression in response to hypoxia with a functionally significant effect on vascular smooth muscle contraction.
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Affiliation(s)
- Michael E Ward
- Division of Respirology, University of Toronto, Toronto, Ontario, Canada.
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Reboul C, Tanguy S, Gibault A, Dauzat M, Obert P. Chronic hypoxia exposure depresses aortic endothelium-dependent vasorelaxation in both sedentary and trained rats: involvement of l-arginine. J Appl Physiol (1985) 2005; 99:1029-35. [PMID: 15831799 DOI: 10.1152/japplphysiol.01122.2004] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study was designed to test the hypothesis that the previously demonstrated training-induced improvement of the endothelium vasodilator function would be blunted under conditions of chronic hypoxia exposure as a result of deleterious effects of hypoxia per se on the nitric oxide pathway. Sea-level-native rats were randomly assigned to N (living in normoxia), NT (living and training 5 days/wk for 5 wk in normoxia), CH (living in hypoxia, 2,800 m), and CHT (living and training 5 days/wk for 5 wk in hypoxia, 2,800 m) groups. Concentration-response curves to acetylcholine (ACh; 10−9 to 10−4 M) with or without l-arginine (10−3 to 10−5 M) and/or nitro-l-arginine methyl ester (10−5 M) were assessed on aortic isolated rings. The main finding was that chronic hypoxia severely depressed maximal ACh-responses of aortic rings in both sedentary and trained groups. However, chronic hypoxia did not interfere with training-induced increases in maximal ACh responses, considering that maximal ACh vasorelaxation was improved in CHT rats to the same extent as in NT rats when both groups were directly compared with their sedentary counterparts. It should be pointed out that the vasodilator response to ACh was restored in CH and CHT rats to the level obtained in N and NT rats, respectively, by an in vitro l-arginine addition. A hypoxia-induced decrease in l-arginine bioavailability resulting from acclimatization at altitude may be involved in this limitation of the NO pathway in CH and CHT rats. These results are of importance for aerobic performance as the specific vascular adaptations to training at altitude could contribute to limit peripheral vasodilatation and subsequently blood flow during exercise.
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Affiliation(s)
- C Reboul
- Dynamique des Incohérences Cardio-Vasculaires, Faculté des Médecine de Nîmes, Montpellier, France
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Ohike Y, Kozaki K, Iijima K, Eto M, Kojima T, Ohga E, Santa T, Imai K, Hashimoto M, Yoshizumi M, Ouchi Y. Amelioration of vascular endothelial dysfunction in obstructive sleep apnea syndrome by nasal continuous positive airway pressure--possible involvement of nitric oxide and asymmetric NG, NG-dimethylarginine. Circ J 2005; 69:221-6. [PMID: 15671617 DOI: 10.1253/circj.69.221] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Asymmetric NG,NG-dimethylarginine (ADMA) is an endogenous inhibitor of endothelial nitric oxide (NO) synthase and its plasma concentration is elevated in patients with cardiovascular risk factors, including hyperlipidemia, hypertension, diabetes, and hyperhomocysteinemia. Obstructive sleep apnea syndrome (OSAS) has been attracting attention as a risk factor for cardiovascular disorders because it often accompanies hypertension, obesity, glucose impairment, and dyslipidemia, all of which are factors in metabolic syndrome and risk factors for cardiovascular disease. METHODS AND RESULTS In the present study, flow-mediated vasodilatation (FMD) of the brachial artery and plasma concentrations of ADMA were measured before and after nasal continuous positive airway pressure (nCPAP) therapy, which abrogates apnea, in 10 male patients aged 36-69 years old, who were given a diagnosis of OSAS by polysomnography. The percent FMD (%FMD) improved significantly from 3.3+/-0.3% to 5.8+/-0.4% (p<0.01) and 6.6+/-0.3% (p<0.01), before, 1 week, and 4 weeks after nCPAP, respectively. At the same time, the plasma NOx concentrations, metabolites of NO, tended to increase, but the plasma ADMA concentration decreased inversely to %FMD and NOx. A negative correlation between %FMD and plasma ADMA concentration, and a positive correlation between %FMD and plasma NOx concentrations were observed. CONCLUSION Nasal CPAP improves endothelial function, in part by the decreasing ADMA concentration, thereby potentiating NO production.
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Affiliation(s)
- Yumiko Ohike
- Department of Geriatric Medicine, University of Tokyo Graduate School of Medicine, Japan
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He J, Yang S, Zhang L. Effects of cocaine on nitric oxide production in bovine coronary artery endothelial cells. J Pharmacol Exp Ther 2005; 314:980-6. [PMID: 15919765 DOI: 10.1124/jpet.105.087452] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cocaine decreases coronary artery endothelial-dependent vasorelaxation. To explore the potential mechanisms, the present study examined the effect of cocaine on nitric oxide release in bovine coronary artery endothelial cells (BCAECs). In the absence of cocaine, basal nitric oxide release from BCAECs continued to accumulate in the medium over the period from 6 to 72 h. Cocaine significantly decreased nitric oxide release at each time point of the study. At 48-h treatment, cocaine (3-30 muM) produced a concentration-dependent decrease in nitric oxide release in BCAECs. In accordance with its inhibition of nitric oxide release, cocaine decreased endothelial nitric-oxide synthase (eNOS) protein levels in BCAECs in a concentration-dependent manner. In addition to the prolonged effect, cocaine pretreatment for 1 h significantly decreased basal and ATP-induced nitric oxide release in BCAECs. Whereas acute cocaine treatment did not affect basal levels of free intracellular calcium concentrations in BCAECs, it significantly decreased the ATP-induced elevation of intracellular calcium and increased its time lag to reach the peak. A quantitative approach by immunofluorescence microscopy revealed that cocaine significantly increased eNOS localized at the cell membrane in BCAECs. Collectively, the results suggest that cocaine inhibits nitric oxide release in BCAECs by decreasing intracellular calcium mobilization, increasing the inactive state of eNOS, and decreasing eNOS protein levels.
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Affiliation(s)
- Jiale He
- Center for Perinatal Biology, Department of Pharmacology and Physiology, Loma Linda University School of Medicine, CA 92350, USA
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Gonzales GF, Chung FA, Miranda S, Valdez LB, Zaobornyj T, Bustamante J, Boveris A. Heart mitochondrial nitric oxide synthase is upregulated in male rats exposed to high altitude (4,340 m). Am J Physiol Heart Circ Physiol 2005; 288:H2568-73. [PMID: 15695556 DOI: 10.1152/ajpheart.00812.2004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Male rats exposed for 21 days to high altitude (4,340 m) responded with arrest of weight gain and increased hematocrit and testosterone levels. High altitude significantly (58%) increased heart mitochondrial nitric oxide (NO) synthase (mtNOS) activity, whereas heart cytosolic endothelial NOS (eNOS) and liver mtNOS were not affected. Western blot analysis found heart mitochondria reacting only with anti-inducible NOS (iNOS) antibodies, whereas the postmitochondrial fraction reacted with anti-iNOS and anti-eNOS antibodies. In vitro-measured NOS activities allowed the estimation of cardiomyocyte capacity for NO production, a value that increased from 57% (sea level) to 79 nmol NO.min(-1).g heart(-1) (4,340 m). The contribution of mtNOS to total cell NO production increased from 62% (sea level) to 71% (4340 m). Heart mtNOS activity showed a linear relationship with hematocrit and a biphasic quadratic association with estradiol and testosterone. Multivariate analysis showed that exposure to high altitude linearly associates with hematocrit and heart mtNOS activity, and that testosterone-to-estradiol ratio and heart weight were not linearly associated with mtNOS activity. We conclude that high altitude triggers a physiological adaptive response that upregulates heart mtNOS activity and is associated in an opposed manner with the serum levels of testosterone and estradiol.
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Affiliation(s)
- Gustavo F Gonzales
- Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, C1113AAD, Buenos Aires, Argentina
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Govindaraju V, Teoh H, Hamid Q, Cernacek P, Ward ME. Interaction between endothelial heme oxygenase-2 and endothelin-1 in altered aortic reactivity after hypoxia in rats. Am J Physiol Heart Circ Physiol 2004; 288:H962-70. [PMID: 15486027 DOI: 10.1152/ajpheart.01218.2003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of this study was to determine whether increased expression of heme oxygenase (HO) contributes to impairment of aortic contractile responses after hypoxia through effects on reactivity to endothelin-1 (ET-1). Thoracic aortas from normoxic rats and rats exposed to hypoxia (10% O2) for 16 or 48 h were mounted in organ bath myographs for contractile studies, fixed in paraformaldehyde, or frozen in liquid nitrogen for protein extraction. In rings from normoxic rats, the HO inhibitor tin protoporphyrin IX (SnPP IX, 10 microM) did not alter the response to phenylephrine or ET-1. In rings from rats exposed to 16-h hypoxia, maximum tension generated in response to these agonists was higher in endothelium-intact but not -denuded rings in the presence of SnPP IX. In rings from rats exposed to 48-h hypoxia SnPP IX increased contraction in endothelium-intact but not -denuded rings. In endothelium-intact aortic rings from rats exposed to 16-h hypoxia incubated with endothelin A receptor-specific antagonist BQ-123 (10(-7) M), SnPP IX did not alter phenylephrine-induced contraction. Aortic ET-1 protein levels, measured by radioimmunoassay, were increased in rats exposed to hypoxia for 16 and 48 h. Western blotting showed that HO-1 and HO-2 protein were increased after 16 h of hypoxia and returned to near-control levels after 48 h. Increase in HO-1 protein was detected in endothelium-intact and -denuded rings. Removal of endothelium abolished the increase in HO-2 immunoreactivity. Immunohistochemistry localized expression of HO-1 protein to vascular smooth muscle, whereas HO-2 was only detected in endothelium. HO-2 is expressed by aortic endothelial cells early during hypoxic exposure and impairs ET-1-mediated potentiation of contraction to alpha-adrenoceptor stimulation.
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Mital S, Loke KE, Chen JM, Mosca RS, Quaegebeur JM, Addonizio LJ, Hintze TH. Mitochondrial respiratory abnormalities in patients with end-stage congenital heart disease. J Heart Lung Transplant 2004; 23:72-9. [PMID: 14734130 DOI: 10.1016/s1053-2498(03)00095-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND Nitric oxide (NO) binds to mitochondrial cytochrome oxidase to decrease myocardial oxygen consumption (MVO(2)). This regulation is disrupted in heart failure (HF) due to reduced NO. The present objective was to evaluate NO-mediated regulation of mitochondrial respiration in the myocardium of patients with congenital heart disease (CHD) and cardiomyopathy (CMP). METHODS MVO(2) was measured in vitro in explanted human myocardium obtained at transplantation. Seven patients had CHD (5 cyanotic, 2 acyanotic), and 11 had non-ischemic CMP. The effects of the following on MVO(2) were measured: kinin-dependent endothelial NO synthase (eNOS) agonists, bradykinin, ramiprilat and amlodipine; NO donors, nitroglycerin and S-nitroso-N-acetylpenicillamine (SNAP) (10(-7) to 10(-4) mol/liter); and NOS inhibitor, N(omega)-nitro-L-arginine methylester (L-NAME). RESULTS eNOS agonists caused a smaller decrease in MVO(2) in CHD compared with CMP patients. Changes in MVO(2) at the highest dose in CHD vs CMP were, respectively: bradykinin, -22 +/- 7% vs: -30 +/- 5% (p < 0.05); ramiprilat, -17 +/- 8% vs -26 +/- 2%, (p < 0.001); and amlodipine, -5 +/- 7% vs -29 +/- 6% (p < 0.001). L-NAME attenuated the effect of bradykinin, ramiprilat and amlodipine in both groups, confirming that the drug effect was secondary to eNOS activation. Nitroglycerin and SNAP also caused smaller decreases in MVO(2) in CHD vs CMP (NTG -16 +/- 6% vs -37 +/- 4%, SNAP -37 +/- 4% vs -49 +/- 3%, [p < 0.01]), suggesting altered mitochondrial function in CHD. CONCLUSIONS Abnormal regulation of MVO(2) in end-stage CMP may be secondary to reduced endogenous NO availability and can be reversed by the use of NO agonists. In end-stage CHD, this abnormality may be related in part to abnormal mitochondrial function.
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Affiliation(s)
- Seema Mital
- Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York, New York, USA.
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López D, Orta X, Casós K, Sáiz MP, Puig-Parellada P, Farriol M, Mitjavila MT. Upregulation of endothelial nitric oxide synthase in rat aorta after ingestion of fish oil-rich diet. Am J Physiol Heart Circ Physiol 2004; 287:H567-72. [PMID: 15059781 DOI: 10.1152/ajpheart.01145.2003] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A previous study with aortic segments isolated from rats fed a fish oil-rich diet indicated an increase in acetylcholine-induced nitric oxide (.NO)-mediated relaxation. However, it remained to be elucidated whether a fish oil-rich diet affects the vascular activity per se and the point of the.NO-cGMP pathway at which fish oil acts. For this purpose, two groups of Sprague-Dawley rats were fed a semipurified diet containing 5% lipids, either corn oil (CO) or menhaden oil (MO), for 8 wk. We studied the mRNA and protein levels of endothelial NO synthase (eNOS) and NOS activity. The bioavailability of vascular.NO was assessed directly by electron spin resonance spectroscopy. The levels of cGMP, l-arginine, and l-citrulline were also evaluated in homogenates. Superoxide anion (O(2)(-).) production and related antioxidant activities were also studied in aortic segments. The aortic content of eNOS mRNA was increased in rats fed the MO-rich diet. This resulted in increases in both eNOS protein levels (70% relative to the rats fed the CO-rich diet) and NOS activity (102%);.NO production increased by 90%, cGMP levels increased by 100%, and l-arginine decreased by 30%. No change in aortic O(2)(-). production was caused by dietary MO. The upregulation of the eNOS-cGMP pathway induced by dietary MO may contribute to the maintenance of vascular homeostasis and explain its beneficial effect in the prevention of arterial diseases.
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Affiliation(s)
- Diego López
- Departament de Fisiologia, Facultat de Biologia, Universitat de Barcelona, E-08028 Barcelona, Spain
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Coulet F, Nadaud S, Agrapart M, Soubrier F. Identification of hypoxia-response element in the human endothelial nitric-oxide synthase gene promoter. J Biol Chem 2003; 278:46230-40. [PMID: 12963737 DOI: 10.1074/jbc.m305420200] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The human endothelial nitric-oxide synthase gene (heNOS) is constitutively expressed in endothelial cells, and its expression is induced under hypoxia. The goal of this study was to search for regulatory elements of the endothelial nitric-oxide synthase (eNOS) gene responsive to hypoxia. Levels of eNOS mRNA, measured by real time reverse transcriptase-PCR analysis, were increased, and heNOS promoter activity was enhanced by hypoxia as compared with normoxia control experiments. Promoter truncation followed by footprint analysis allowed the mapping and identification of the hypoxia-responsive elements at position -5375 to -5366, closely related to hypoxia-inducible factor (HIF)-responsive element (HRE). To test whether known HIF-1 and HIF-2 are involved in hypoxia-induced heNOS promoter activation, HMEC-1 and HUVEC were transiently transfected with HIF-1alpha and HIF-1beta or HIF-2alpha and HIF-1beta expression vectors. Exogenous HIF-2 markedly increased luciferase reporter activity driven by the heNOS promoter in its native location. The induction of luciferase was conserved with the antisense construct and was increased in cotransfection experiments when this fragment was cloned 5' to the proximal 785-bp fragment of the eNOS promoter. Deletion analysis and site-directed mutagenesis demonstrated that the two contiguous HIF consensus binding sites spanning bp -5375 to -5366 relative to the transcription start site were both functional for heNOS promoter activity induction by hypoxia and by HIF-2 overexpression. In conclusion, we demonstrate that heNOS is a hypoxia-inducible gene, whose transcription is stimulated through HIF-2 interaction with two contiguous HRE sites located at -5375 to -5366 of the heNOS promoter.
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Affiliation(s)
- Florence Coulet
- INSERM, Unit 525, Université Pierre et Marie Curie, Faculté de Médecine Pitié-Salpêtrière, 91 Boulevard de l'Hôpital, 75013 Paris, France
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White MM, Zhang L. Effects of chronic hypoxia on maternal vasodilation and vascular reactivity in guinea pig and ovine pregnancy. High Alt Med Biol 2003; 4:157-69. [PMID: 12855049 DOI: 10.1089/152702903322022776] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
During pregnancy, exposure to chronic hypoxia is thought to be associated with an increased risk of preeclampsia and fetal intrauterine growth restriction (IUGR). While some studies suggest that this process may be mediated through effects of chronic hypoxia on uterine artery vasodilation and growth, these observations are likely to be species specific and may represent genetic variability in maternal adaptation to hypoxia. This review is a comparative analysis of the effects of chronic hypoxia on vascular reactivity in pregnant and nonpregnant guinea pig and sheep. Data suggest that exposure to chronic hypoxia is associated with enhanced uterine artery blood flow in the sheep, whereas, in the guinea pig, blood flow is decreased.
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Affiliation(s)
- Margueritte M White
- Division of Cardiology, University of Colorado Health Sciences Center, Denver, CO, USA.
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Brevetti LS, Chang DS, Tang GL, Sarkar R, Messina LM. Overexpression of endothelial nitric oxide synthase increases skeletal muscle blood flow and oxygenation in severe rat hind limb ischemia. J Vasc Surg 2003; 38:820-6. [PMID: 14560236 DOI: 10.1016/s0741-5214(03)00555-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Although nitric oxide (NO) has a critical role in angiogenesis, the therapeutic potential of NO synthase overexpression in severe ischemia remains undefined. We tested the hypothesis that overexpression of endothelial NO synthase (eNOS) would improve tissue perfusion in severe hind limb ischemia. METHODS Severe hind limb ischemia was induced in 122 adult male Sprague-Dawley rats. Ten days after the induction of hind limb ischemia, vascular isolation and intraarterial delivery of an adenoviral vector encoding eNOS (AdeNOS), a control adenoviral vector (AdE1), or phosphate-buffered saline solution (PBS) was performed. Skeletal muscle blood flow, muscle oxygen tension, angiography, and immunohistochemistry for capillary counts were measured. RESULTS Gene transfer of AdeNOS increased eNOS protein expression and enzyme activity. Two weeks after gene transfer, skeletal muscle blood flow was fourfold higher in eNOS-transduced than in AdE1-transduced or PBS treated rats and was similar to exercise-induced maximal flow in nonischemic muscle. eNOS overexpression increased muscle oxygen tension in a titer-dependent fashion. This increase persisted 1 month after transduction, even though eNOS enzyme activity had declined to normal levels. Angiography and capillary counts showed that eNOS overexpression increased the size and number of collateral arteries, but did not significantly increase the capillary-muscle fiber ratio. CONCLUSIONS eNOS overexpression in an ischemic rat hind limb significantly increased skeletal muscle blood flow, muscle oxygen tension, and collateral arteries (arteriogenesis). Furthermore, eNOS overexpression did not result in capillary angiogenesis above control levels. These studies demonstrate the potential for eNOS overexpression as treatment for severe limb ischemia in human beings.
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Affiliation(s)
- Lucy S Brevetti
- Division of Vascular Surgery, Pacific Vascular Research Laboratory, University of California-San Francisco, 505 Parnassus Avenue, San Francisco, CA 94143, USA
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Hare GMT, Mazer CD, Mak W, Gorczynski RM, Hum KM, Kim SY, Wyard L, Barr A, Qu R, Baker AJ. Hemodilutional anemia is associated with increased cerebral neuronal nitric oxide synthase gene expression. J Appl Physiol (1985) 2003; 94:2058-67. [PMID: 12533500 DOI: 10.1152/japplphysiol.00931.2002] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Severe hemodilutional anemia may reduce cerebral oxygen delivery, resulting in cerebral tissue hypoxia. Increased nitric oxide synthase (NOS) expression has been identified following cerebral hypoxia and may contribute to the compensatory increase in cerebral blood flow (CBF) observed after hypoxia and anemia. However, changes in cerebral NOS gene expression have not been reported after acute anemia. This study tests the hypothesis that acute hemodilutional anemia causes cerebral tissue hypoxia, triggering changes in cerebral NOS gene expression. Anesthetized rats underwent hemodilution when 30 ml/kg of blood were exchanged with pentastarch, resulting in a final hemoglobin concentration of 51.0 +/- 1.2 g/l (n = 7 rats). Caudate tissue oxygen tension (Pbr(O(2))) decreased transiently from 17.3 +/- 4.1 to 14.4 +/- 4.1 Torr (P < 0.05), before returning to baseline after approximately 20 min. An increase in CBF may have contributed to restoring Pbr(O(2)) by improving cerebral tissue oxygen delivery. An increase in neuronal NOS (nNOS) mRNA was detected by RT-PCR in the cerebral cortex of anemic rats after 3 h (P < 0.05, n = 5). A similar response was observed after exposure to hypoxia. By contrast, no increases in mRNA for endothelial NOS or interleukin-1beta were observed after anemia or hypoxia. Hemodilutional anemia caused an acute reduction in Pbr(O(2)) and an increase in cerebral cortical nNOS mRNA, supporting a role for nNOS in the physiological response to acute anemia.
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Affiliation(s)
- Gregory M T Hare
- Department of Anaesthesia, University of Toronto, St. Michael's Hospital, Toronto M5B 1W8, Canada.
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Earley S, Walker BR. Increased nitric oxide production following chronic hypoxia contributes to attenuated systemic vasoconstriction. Am J Physiol Heart Circ Physiol 2003; 284:H1655-61. [PMID: 12511430 DOI: 10.1152/ajpheart.00964.2002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Attenuated vasoconstrictor reactivity following chronic hypoxia (CH) is associated with endothelium-dependent vascular smooth muscle (VSM) cell hyperpolarization and diminished intracellular [Ca(2+)]. We tested the hypothesis that increased production of nitric oxide (NO) after CH contributes to blunted vasoconstrictor responsiveness. We found that basal NO production of mesenteric arteries from CH rats (barometric pressure = 380 Torr; 48 h) was greater than that of controls (barometric pressure = 630 Torr). In addition, studies employing pressurized mesenteric arteries (100-200 microM ID) abluminally loaded with the Ca(2+) indicator fura 2-AM demonstrated that although NO synthase (NOS) inhibition normalized agonist-induced vasoconstrictor responses between groups, VSM cell [Ca(2+)] in vessels from CH rats remained diminished compared with controls. To determine whether elevated NO production following CH results from increased NOS protein levels, we performed Western blots for NOS isoforms by using mesenteric arteries from control and CH rats. Endothelial NOS levels did not differ between groups, and other NOS isoforms were not detected in these samples. Selective endothelial loading of fura 2-AM was employed to test the hypothesis that elevated endothelial cell [Ca(2+)] following CH accounts for enhanced NOS activity. These experiments demonstrated greater endothelial cell [Ca(2+)] in mesenteric arteries isolated from CH rats compared with controls. We conclude that enhanced production of NO resulting from elevated endothelial cell [Ca(2+)] contributes to attenuated reactivity following CH by decreasing VSM cell Ca(2+) sensitivity.
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Affiliation(s)
- Scott Earley
- Vascular Physiology Group, Department of Cell Biology & Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.
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