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Bahadoran Z, Mirmiran P, Kashfi K, Ghasemi A. Vascular nitric oxide resistance in type 2 diabetes. Cell Death Dis 2023; 14:410. [PMID: 37433795 PMCID: PMC10336063 DOI: 10.1038/s41419-023-05935-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 06/18/2023] [Accepted: 06/28/2023] [Indexed: 07/13/2023]
Abstract
Vascular nitric oxide (NO•) resistance, manifested by an impaired vasodilator function of NO• in both the macro- and microvessels, is a common state in type 2 diabetes (T2D) associated with developing cardiovascular events and death. Here, we summarize experimental and human evidence of vascular NO• resistance in T2D and discuss its underlying mechanisms. Human studies indicate a ~ 13-94% decrease in the endothelium (ET)-dependent vascular smooth muscle (VSM) relaxation and a 6-42% reduced response to NO• donors, i.e., sodium nitroprusside (SNP) and glyceryl trinitrate (GTN), in patients with T2D. A decreased vascular NO• production, NO• inactivation, and impaired responsiveness of VSM to NO• [occurred due to quenching NO• activity, desensitization of its receptor soluble guanylate cyclase (sGC), and/or impairment of its downstream pathway, cyclic guanosine monophosphate (cGMP)-protein kinase G (PKG)] are the known mechanisms underlying the vascular NO• resistance in T2D. Hyperglycemia-induced overproduction of reactive oxygen species (ROS) and vascular insulin resistance are key players in this state. Therefore, upregulating vascular NO• availability, re-sensitizing or bypassing the non-responsive pathways to NO•, and targeting key vascular sources of ROS production may be clinically relevant pharmacological approaches to circumvent T2D-induced vascular NO• resistance.
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Affiliation(s)
- Zahra Bahadoran
- Nutrition and Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Parvin Mirmiran
- Department of Clinical Nutrition, Faculty of Nutrition Sciences and Food Technology, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Khosrow Kashfi
- Department of Molecular, Cellular, and Biomedical Sciences, Sophie Davis School of Biomedical Education, City University of New York School of Medicine, New York, NY, 10031, USA
| | - Asghar Ghasemi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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2
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Wijnands KAP, Meesters DM, Vandendriessche B, Briedé JJ, van Eijk HMH, Brouckaert P, Cauwels A, Lamers WH, Poeze M. Microcirculatory Function during Endotoxemia-A Functional Citrulline-Arginine-NO Pathway and NOS3 Complex Is Essential to Maintain the Microcirculation. Int J Mol Sci 2021; 22:ijms222111940. [PMID: 34769369 PMCID: PMC8584871 DOI: 10.3390/ijms222111940] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 11/01/2021] [Accepted: 11/01/2021] [Indexed: 02/02/2023] Open
Abstract
Competition for the amino acid arginine by endothelial nitric-oxide synthase (NOS3) and (pro-)inflammatory NO-synthase (NOS2) during endotoxemia appears essential in the derangement of the microcirculatory flow. This study investigated the role of NOS2 and NOS3 combined with/without citrulline supplementation on the NO-production and microcirculation during endotoxemia. Wildtype (C57BL6/N background; control; n = 36), Nos2-deficient, (n = 40), Nos3-deficient (n = 39) and Nos2/Nos3-deficient mice (n = 42) received a continuous intravenous LPS infusion alone (200 μg total, 18 h) or combined with L-citrulline (37.5 mg, last 6 h). The intestinal microcirculatory flow was measured by side-stream dark field (SDF)-imaging. The jejunal intracellular NO production was quantified by in vivo NO-spin trapping combined with electron spin-resonance (ESR) spectrometry. Amino-acid concentrations were measured by high-performance liquid chromatography (HPLC). LPS infusion decreased plasma arginine concentration in control and Nos3−/− compared to Nos2−/− mice. Jejunal NO production and the microcirculation were significantly decreased in control and Nos2−/− mice after LPS infusion. No beneficial effects of L-citrulline supplementation on microcirculatory flow were found in Nos3−/− or Nos2−/−/Nos3−/− mice. This study confirms that L-citrulline supplementation enhances de novo arginine synthesis and NO production in mice during endotoxemia with a functional NOS3-enzyme (control and Nos2−/− mice), as this beneficial effect was absent in Nos3−/− or Nos2−/−/Nos3−/− mice.
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Affiliation(s)
- Karolina A. P. Wijnands
- Department of Surgery, NUTRIM School of Nutrition, Translational Research in Metabolism, Maastricht University Medical Center, 6229 ER Maastricht, The Netherlands; (D.M.M.); (H.M.H.v.E.); (M.P.)
- Correspondence: ; Tel.: +31-650-513-913
| | - Dennis M. Meesters
- Department of Surgery, NUTRIM School of Nutrition, Translational Research in Metabolism, Maastricht University Medical Center, 6229 ER Maastricht, The Netherlands; (D.M.M.); (H.M.H.v.E.); (M.P.)
- Department of Genetics & Cell Biology, NUTRIM School of Nutrition, Translational Research in Metabolism, Maastricht University Medical Center, 6229 ER Maastricht, The Netherlands
| | - Benjamin Vandendriessche
- VIB Inflammation Research Center, 9052 Ghent, Belgium; (B.V.); (P.B.); (A.C.)
- Department of Biomedical Molecular Biology, Ghent University, 9000 Ghent, Belgium
- Byteflies, 2600 Antwerp, Belgium
- Department of Electrical, Computer and Systems Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Jacob J. Briedé
- Department of Toxicogenomics, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, 6229 ER Maastricht, The Netherlands;
| | - Hans M. H. van Eijk
- Department of Surgery, NUTRIM School of Nutrition, Translational Research in Metabolism, Maastricht University Medical Center, 6229 ER Maastricht, The Netherlands; (D.M.M.); (H.M.H.v.E.); (M.P.)
| | - Peter Brouckaert
- VIB Inflammation Research Center, 9052 Ghent, Belgium; (B.V.); (P.B.); (A.C.)
- Department of Biomedical Molecular Biology, Ghent University, 9000 Ghent, Belgium
| | - Anje Cauwels
- VIB Inflammation Research Center, 9052 Ghent, Belgium; (B.V.); (P.B.); (A.C.)
- Department of Biomedical Molecular Biology, Ghent University, 9000 Ghent, Belgium
- Orionis Biosciences, 9052 Ghent, Belgium
| | - Wouter H. Lamers
- Department of Anatomy & Embryology, NUTRIM School of Nutrition, Translational Research in Metabolism, Maastricht University Medical Center, 6229 ER Maastricht, The Netherlands;
| | - Martijn Poeze
- Department of Surgery, NUTRIM School of Nutrition, Translational Research in Metabolism, Maastricht University Medical Center, 6229 ER Maastricht, The Netherlands; (D.M.M.); (H.M.H.v.E.); (M.P.)
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3
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Portörő I, Mukli P, Kocsis L, Hermán P, Caccia D, Perrella M, Mozzarelli A, Ronda L, Mathe D, Eke A. Model-based evaluation of the microhemodynamic effects of PEGylated HBOC molecules in the rat brain cortex: a laser speckle imaging study. BIOMEDICAL OPTICS EXPRESS 2020; 11:4150-4175. [PMID: 32923034 PMCID: PMC7449705 DOI: 10.1364/boe.388089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 04/24/2020] [Accepted: 05/04/2020] [Indexed: 06/11/2023]
Abstract
Hemoglobin-based oxygen carriers (HBOCs) were developed with the aim of substituting transfusions in emergency events. However, they exhibit adverse events, such as nitric oxide (NO) scavenging, vasoactivity, enhanced platelet aggregation, presently hampering their clinical application. The impact of two prototypical PEGylated HBOCs, Euro-PEG-Hb and PEG-HbO2, endowed by different oxygen affinities and hydrodynamic volumes, was assessed on the cerebrocortical parenchymal microhemodynamics, and extravasation through the blood-brain-barrier (BBB) by laser speckle contrast imaging (LSCI) method and near-infrared (NIR) imaging, respectively. By evaluating voxel-wise cerebrocortical red blood cell velocity, non-invasively for its mean kernel-wise value ( v ¯ RBC ), and model-derived kernel-wise predictions for microregional tissue hematocrit, THt, and fractional change in hematocrit-corrected vascular resistance, R', as measures of potential adverse effects (enhanced platelet aggregation and vasoactivity, respectively) we found i) no significant difference between tested HBOCs in the systemic and microregional parameters, and in the relative spatial dispersion of THt, and R' as additional measures of HBOC-related adverse effects, and ii) no extravasation through BBB by Euro-PEG-Hb. We conclude that Euro-PEG-Hb does not exhibit adverse effects in the brain microcirculation that could be directly attributed to NO scavenging.
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Affiliation(s)
- István Portörő
- Institute of Translational Medicine, Semmelweis University, Hungary
- These authors contributed equally to this work
| | - Péter Mukli
- Institute of Translational Medicine, Semmelweis University, Hungary
- Department of Physiology, Semmelweis University, Hungary
- These authors contributed equally to this work
| | - László Kocsis
- Institute of Translational Medicine, Semmelweis University, Hungary
| | - Péter Hermán
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT 06520, USA
| | - Dario Caccia
- Department of Biomedical Science and Technology, University of Milan, Italy
- Department of Food and Drug, University of Parma, Italy
| | - Michele Perrella
- Department of Biomedical Science and Technology, University of Milan, Italy
| | - Andrea Mozzarelli
- Department of Food and Drug, University of Parma, Italy
- Institute of Biophysics, National Research Council, Pisa, Italy
- Biopharmanet-TEC, University of Parma, Italy
| | - Luca Ronda
- Institute of Biophysics, National Research Council, Pisa, Italy
- Biopharmanet-TEC, University of Parma, Italy
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Domokos Mathe
- CROmed Research and Service Centers Ltd., Budapest, Hungary
| | - Andras Eke
- Institute of Translational Medicine, Semmelweis University, Hungary
- Department of Physiology, Semmelweis University, Hungary
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Haselden WD, Kedarasetti RT, Drew PJ. Spatial and temporal patterns of nitric oxide diffusion and degradation drive emergent cerebrovascular dynamics. PLoS Comput Biol 2020; 16:e1008069. [PMID: 32716940 PMCID: PMC7410342 DOI: 10.1371/journal.pcbi.1008069] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 08/06/2020] [Accepted: 06/17/2020] [Indexed: 02/07/2023] Open
Abstract
Nitric oxide (NO) is a gaseous signaling molecule that plays an important role in neurovascular coupling. NO produced by neurons diffuses into the smooth muscle surrounding cerebral arterioles, driving vasodilation. However, the rate of NO degradation in hemoglobin is orders of magnitude higher than in brain tissue, though how this might impact NO signaling dynamics is not completely understood. We used simulations to investigate how the spatial and temporal patterns of NO generation and degradation impacted dilation of a penetrating arteriole in cortex. We found that the spatial location of NO production and the size of the vessel both played an important role in determining its responsiveness to NO. The much higher rate of NO degradation and scavenging of NO in the blood relative to the tissue drove emergent vascular dynamics. Large vasodilation events could be followed by post-stimulus constrictions driven by the increased degradation of NO by the blood, and vasomotion-like 0.1-0.3 Hz oscillations could also be generated. We found that these dynamics could be enhanced by elevation of free hemoglobin in the plasma, which occurs in diseases such as malaria and sickle cell anemia, or following blood transfusions. Finally, we show that changes in blood flow during hypoxia or hyperoxia could be explained by altered NO degradation in the parenchyma. Our simulations suggest that many common vascular dynamics may be emergent phenomena generated by NO degradation by the blood or parenchyma.
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Affiliation(s)
- William Davis Haselden
- Neuroscience Graduate Program, MD/PhD Medical Scientist Training Program, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Ravi Teja Kedarasetti
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Patrick J. Drew
- Neuroscience Graduate Program, MD/PhD Medical Scientist Training Program, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Departments of Biomedical Engineering and Neurosurgery, Pennsylvania State University, University Park, Pennsylvania, United States of America
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Parise G, Murrant CL, Cocks M, Snijders T, Baum O, Plyley MJ. Capillary facilitation of skeletal muscle function in health and disease. Appl Physiol Nutr Metab 2020; 45:453-462. [DOI: 10.1139/apnm-2019-0416] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Skeletal muscle is highly vascularized, with perfusion being tightly regulated to meet wide-ranging metabolic demands. For decades, the capillary supply has been explored mainly in terms of evaluating the capillary numbers and their function in the supply of oxygen and substrates and the removal of metabolic byproducts. This review will focus on recent discoveries concerning the role played by capillaries in facilitating other aspects of cell regulation and maintenance, in health and disease, as well as alterations during the aging process. Novelty Capillaries play a central role in the coordination of the vascular response that controls blood flow during contraction and the cellular responses to which they feed into. Nitric oxide is an important regulatory compound within the cardiovascular system, and a significant contributor to skeletal muscle capillary angiogenesis and vasodilatory response to agonists. The microvascular network between muscle fibres may play a critical role in the distribution of signalling factors necessary for optimal muscle satellite cell function.
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Affiliation(s)
- Gianni Parise
- McMaster University, Departments of Kinesiology and Medical Physics & Applied Radiation Science, Hamilton, ON L8S 4K1, Canada
| | - Coral L. Murrant
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Matthew Cocks
- Liverpool John Moores University, Research Institute for Sport and Exercise Sciences, Liverpool, L3 5UG, UK
| | - Tim Snijders
- Maastricht University, NUTRIM School of Nutrition and Translational Research in Metabolism, Department of Human Biology, Maastricht 6200 MD, the Netherlands
| | - Oliver Baum
- Institute of Physiology, Charité-Universitäts medizin Berlin, Berlin D-10117, Germany
| | - Michael J. Plyley
- Brock University, Department of Kinesiology, St. Catharines, ON L2S 3A1, Canada
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Bahadoran Z, Carlström M, Mirmiran P, Ghasemi A. Nitric oxide: To be or not to be an endocrine hormone? Acta Physiol (Oxf) 2020; 229:e13443. [PMID: 31944587 DOI: 10.1111/apha.13443] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 01/05/2020] [Accepted: 01/10/2020] [Indexed: 01/02/2023]
Abstract
Nitric oxide (NO), a highly reactive gasotransmitter, is critical for a number of cellular processes and has multiple biological functions. Due to its limited lifetime and diffusion distance, NO has been mainly believed to act in autocrine/paracrine fashion. The increasingly recognized effects of pharmacologically delivered and endogenous NO at a distant site have changed the conventional wisdom and introduced NO as an endocrine signalling molecule. The notion is greatly supported by the detection of a number of NO adducts and their circulatory cycles, which in turn contribute to the transport and delivery of NO bioactivity, remote from the sites of its synthesis. The existence of endocrine sites of synthesis, negative feedback regulation of biosynthesis, integrated storage and transport systems, having an exclusive receptor, that is, soluble guanylyl cyclase (sGC), and organized circadian rhythmicity make NO something beyond a simple autocrine/paracrine signalling molecule that could qualify for being an endocrine signalling molecule. Here, we discuss hormonal features of NO from the classical endocrine point of view and review available knowledge supporting NO as a true endocrine hormone. This new insight can provide a new framework within which to reinterpret NO biology and its clinical applications.
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Affiliation(s)
- Zahra Bahadoran
- Nutrition and Endocrine Research Center Research Institute for Endocrine Sciences Shahid Beheshti University of Medical Sciences Tehran Iran
| | - Mattias Carlström
- Department of Physiology and Pharmacology Karolinska Institutet Stockholm Sweden
| | - Parvin Mirmiran
- Department of Clinical Nutrition and Dietetics Faculty of Nutrition Sciences and Food Technology National Nutrition and Food Technology Research Institute Shahid Beheshti University of Medical Sciences Tehran Iran
| | - Asghar Ghasemi
- Endocrine Physiology Research Center Research Institute for Endocrine Sciences Shahid Beheshti University of Medical Sciences Tehran Iran
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7
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Tyml K. Vitamin C and Microvascular Dysfunction in Systemic Inflammation. Antioxidants (Basel) 2017; 6:antiox6030049. [PMID: 28661424 PMCID: PMC5618077 DOI: 10.3390/antiox6030049] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 06/26/2017] [Accepted: 06/27/2017] [Indexed: 02/07/2023] Open
Abstract
Sepsis, life-threatening organ dysfunction caused by a dysfunctional host response to infection, is associated with high mortality. A promising strategy to improve the outcome is to inject patients intravenously with ascorbate (vitamin C). In animal models of sepsis, this injection improves survival and, among others, the microvascular function. This review examines our recent work addressing ascorbate's ability to inhibit arteriolar dysfunction and capillary plugging in sepsis. Arteriolar dysfunction includes impaired vasoconstriction/dilation (previously reviewed) and impaired conduction of vasoconstriction/dilation along the arteriole. We showed that ascorbate injected into septic mice prevents impaired conducted vasoconstriction by inhibiting neuronal nitric oxide synthase-derived NO, leading to restored inter-endothelial electrical coupling through connexin 37-containing gap junctions. Hypoxia/reoxygenation (confounding factor in sepsis) also impairs electrical coupling by protein kinase A (PKA)-dependent connexin 40 dephosphorylation; ascorbate restores PKA activation required for this coupling. Both effects of ascorbate could explain its ability to protect against hypotension in sepsis. Capillary plugging in sepsis involves P-selectin mediated platelet-endothelial adhesion and microthrombi formation. Early injection of ascorbate prevents capillary plugging by inhibiting platelet-endothelial adhesion and endothelial surface P-selectin expression. Ascorbate also prevents thrombin-induced platelet aggregation and platelet surface P-selectin expression, thus preventing microthrombi formation. Delayed ascorbate injection reverses capillary plugging and platelet-endothelial adhesion; it also attenuates sepsis-induced drop in platelet count in systemic blood. Thrombin-induced release of plasminogen-activator-inhibitor-1 from platelets (anti-fibrinolytic event in sepsis) is inhibited by ascorbate pH-dependently. Thus, under acidotic conditions in sepsis, ascorbate promotes dissolving of microthrombi in capillaries. We propose that protected/restored arteriolar conduction and capillary bed perfusion by ascorbate contributes to reduced organ injury and improved survival in sepsis.
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Affiliation(s)
- Karel Tyml
- Centre for Critical Illness Research, Lawson Health Research Institute, London, ON N6A 5W9, Canada.
- Department of Medical Biophysics, University of Western Ontario, London, ON N6A 5C1, Canada.
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8
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Liu Y, Buerk DG, Barbee KA, Jaron D. Nitric oxide release by deoxymyoglobin nitrite reduction during cardiac ischemia: A mathematical model. Microvasc Res 2017; 112:79-86. [PMID: 28363495 DOI: 10.1016/j.mvr.2017.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 03/16/2017] [Accepted: 03/19/2017] [Indexed: 12/19/2022]
Abstract
Interactions between cardiac myoglobin (Mb), nitrite, and nitric oxide (NO) are vital in regulating O2 storage, transport, and NO homeostasis. Production of NO through the reduction of endogenous myocardial nitrite by deoxygenated myoglobin has been shown to significantly reduce myocardial infarction damage and ischemic injury. We developed a mathematical model for a cardiac arteriole and surrounding myocardium to examine the hypothesis that myoglobin switches functions from being a strong NO scavenger to an NO producer via the deoxymyoglobin nitrite reductase pathway. Our results predict that under ischemic conditions of flow, blood oxygen level, and tissue pH, deoxyMb nitrite reduction significantly elevates tissue and smooth muscle cell NO. The size of the effect is consistent at different flow rates, increases with decreasing blood oxygen and tissue pH and, in extreme pathophysiological conditions, NO can even be elevated above the normoxic levels. Our simulations suggest that cardiac deoxyMb nitrite reduction is a plausible mechanism for preserving or enhancing NO levels using endogenous nitrite despite the rate-limiting O2 levels for endothelial NO production. This NO could then be responsible for mitigating deleterious effects under ischemic conditions.
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Affiliation(s)
- Yien Liu
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3140 Market St., Philadelphia, PA 19104, USA
| | - Donald G Buerk
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3140 Market St., Philadelphia, PA 19104, USA
| | - Kenneth A Barbee
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3140 Market St., Philadelphia, PA 19104, USA
| | - Dov Jaron
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3140 Market St., Philadelphia, PA 19104, USA.
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Cocks M, Wagenmakers AJM. The effect of different training modes on skeletal muscle microvascular density and endothelial enzymes controlling NO availability. J Physiol 2015; 594:2245-57. [PMID: 25809076 DOI: 10.1113/jp270329] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 03/16/2015] [Indexed: 01/12/2023] Open
Abstract
It is becoming increasingly apparent that a high vasodilator response of the skeletal muscle microvasculature to insulin and exercise is of critical importance for adequate muscle perfusion and long-term microvascular and muscle metabolic health. Previous research has shown that a sedentary lifestyle, obesity and ageing lead to impairments in the vasodilator response, while a physically active lifestyle keeps both microvascular density and vasodilator response high. To investigate the molecular mechanisms behind these impairments and the benefits of exercise training interventions, our laboratory has recently developed quantitative immunofluorescence microscopy methods to measure protein content of eNOS and NAD(P)Hoxidase specifically in the endothelial layer of capillaries and arterioles of human skeletal muscle. As eNOS produces nitric oxide (NO) and NAD(P)Hoxidase produces superoxide anions (O2 (-) , quenching NO) we propose that the eNOS/NAD(P)Hoxidase protein ratio is a marker of vasodilator capacity. The novel methods show that endurance training (ET) and high intensity interval training (HIT), generally regarded as a time-efficient alternative to ET, increase eNOS protein content and the eNOS/NADP(H)oxidase protein ratio in previously sedentary lean and obese young men. Resistance exercise training had smaller but qualitatively similar effects. Western blot data of other laboratories suggest that endurance exercise training leads to similar changes in sedentary elderly men. Future research will be required to investigate the relative importance of other sources and tissues in the balance between NO and O2 (-) production seen by the vascular smooth muscle layer of terminal arterioles.
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Affiliation(s)
- Matthew Cocks
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Tom Reilly Building, Byrom Street, Liverpool, L3 3AF, UK
| | - Anton J M Wagenmakers
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Tom Reilly Building, Byrom Street, Liverpool, L3 3AF, UK
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Dyson RM, Palliser HK, Latter JL, Kelly MA, Chwatko G, Glowacki R, Wright IMR. Interactions of the gasotransmitters contribute to microvascular tone (dys)regulation in the preterm neonate. PLoS One 2015; 10:e0121621. [PMID: 25807236 PMCID: PMC4373676 DOI: 10.1371/journal.pone.0121621] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 02/02/2015] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND & AIMS Hydrogen sulphide (H2S), nitric oxide (NO), and carbon monoxide (CO) are involved in transitional microvascular tone dysregulation in the preterm infant; however there is conflicting evidence on the interaction of these gasotransmitters, and their overall contribution to the microcirculation in newborns is not known. The aim of this study was to measure the levels of all 3 gasotransmitters, characterise their interrelationships and elucidate their combined effects on microvascular blood flow. METHODS 90 preterm neonates were studied at 24h postnatal age. Microvascular studies were performed by laser Doppler. Arterial COHb levels (a measure of CO) were determined through co-oximetry. NO was measured as nitrate and nitrite in urine. H2S was measured as thiosulphate by liquid chromatography. Relationships between levels of the gasotransmitters and microvascular blood flow were assessed through partial correlation controlling for the influence of gestational age. Structural equation modelling was used to examine the combination of these effects on microvascular blood flow and derive a theoretical model of their interactions. RESULTS No relationship was observed between NO and CO (p = 0.18, r = 0.18). A positive relationship between NO and H2S (p = 0.008, r = 0.28) and an inverse relationship between CO and H2S (p = 0.01, r = -0.33) exists. Structural equation modelling was used to examine the combination of these effects on microvascular blood flow. The model with the best fit is presented. CONCLUSIONS The relationships between NO and H2S, and CO and H2S may be of importance in the preterm newborn, particularly as NO levels in males are associated with higher H2S levels and higher microvascular blood flow and CO in females appears to convey protection against vascular dysregulation. Here we present a theoretical model of these interactions and their overall effects on microvascular flow in the preterm newborn, upon which future mechanistic studies may be based.
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Affiliation(s)
- Rebecca M. Dyson
- Mothers and Babies Research Centre, Hunter Medical Research Institute, New Lambton Heights, NSW, 2305, Australia
- School of Medicine and Public Health, University of Newcastle, Callaghan, NSW, 2308, Australia
- Illawarra Health and Medical Research Institute and Graduate School of Medicine, University of Wollongong, NSW, 2522, Australia
| | - Hannah K. Palliser
- Mothers and Babies Research Centre, Hunter Medical Research Institute, New Lambton Heights, NSW, 2305, Australia
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Joanna L. Latter
- Mothers and Babies Research Centre, Hunter Medical Research Institute, New Lambton Heights, NSW, 2305, Australia
- School of Medicine and Public Health, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Megan A. Kelly
- Illawarra Health and Medical Research Institute and Graduate School of Medicine, University of Wollongong, NSW, 2522, Australia
| | - Grazyna Chwatko
- Department of Environmental Chemistry, Faculty of Chemistry, University of Lodz, 90–236, Lodz, Poland
| | - Rafal Glowacki
- Department of Environmental Chemistry, Faculty of Chemistry, University of Lodz, 90–236, Lodz, Poland
| | - Ian M. R. Wright
- Mothers and Babies Research Centre, Hunter Medical Research Institute, New Lambton Heights, NSW, 2305, Australia
- School of Medicine and Public Health, University of Newcastle, Callaghan, NSW, 2308, Australia
- Illawarra Health and Medical Research Institute and Graduate School of Medicine, University of Wollongong, NSW, 2522, Australia
- Kaleidoscope Neonatal Intensive Care Unit, John Hunter Children’s Hospital, New Lambton Heights, NSW, 2305, Australia
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11
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Wijnands KAP, Castermans TMR, Hommen MPJ, Meesters DM, Poeze M. Arginine and citrulline and the immune response in sepsis. Nutrients 2015; 7:1426-63. [PMID: 25699985 PMCID: PMC4377861 DOI: 10.3390/nu7031426] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Revised: 01/15/2015] [Accepted: 01/26/2015] [Indexed: 01/01/2023] Open
Abstract
Arginine, a semi-essential amino acid is an important initiator of the immune response. Arginine serves as a precursor in several metabolic pathways in different organs. In the immune response, arginine metabolism and availability is determined by the nitric oxide synthases and the arginase enzymes, which convert arginine into nitric oxide (NO) and ornithine, respectively. Limitations in arginine availability during inflammatory conditions regulate macrophages and T-lymfocyte activation. Furthermore, over the past years more evidence has been gathered which showed that arginine and citrulline deficiencies may underlie the detrimental outcome of inflammatory conditions, such as sepsis and endotoxemia. Not only does the immune response contribute to the arginine deficiency, also the impaired arginine de novo synthesis in the kidney has a key role in the eventual observed arginine deficiency. The complex interplay between the immune response and the arginine-NO metabolism is further underscored by recent data of our group. In this review we give an overview of physiological arginine and citrulline metabolism and we address the experimental and clinical studies in which the arginine-citrulline NO pathway plays an essential role in the immune response, as initiator and therapeutic target.
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Affiliation(s)
- Karolina A P Wijnands
- Department of Surgery, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Center, Maastricht 6200 MD, The Netherlands.
| | - Tessy M R Castermans
- Department of Surgery, Maastricht University Medical Center, Maastricht 6200MD, The Netherlands.
| | - Merel P J Hommen
- Department of Surgery, Maastricht University Medical Center, Maastricht 6200MD, The Netherlands.
| | - Dennis M Meesters
- Department of Surgery, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Center, Maastricht 6200 MD, The Netherlands.
| | - Martijn Poeze
- Department of Surgery, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Center, Maastricht 6200 MD, The Netherlands.
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12
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Sarwar M, Samuel CS, Bathgate RA, Stewart DR, Summers RJ. Serelaxin-mediated signal transduction in human vascular cells: bell-shaped concentration-response curves reflect differential coupling to G proteins. Br J Pharmacol 2014; 172:1005-19. [PMID: 25297987 DOI: 10.1111/bph.12964] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 09/16/2014] [Accepted: 09/24/2014] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE In a recently conducted phase III clinical trial, RELAX-AHF, serelaxin infusion over 48 h improved short- and long-term clinical outcomes in patients with acute heart failure. In this study we used human primary cells from the umbilical vasculature to better understand the signalling mechanisms activated by serelaxin. EXPERIMENTAL APPROACH We examined the acute effects of serelaxin on signal transduction mechanisms in primary human umbilical vascular cells and its chronic actions on markers of cardiovascular function and disease. KEY RESULTS The RXFP1 receptor, the cognate serelaxin receptor, was expressed at the cell surface in HUVECs and human umbilical vein smooth muscle cells (HUVSMCs), human umbilical artery smooth muscle cells (HUASMCs) and human cardiac fibroblasts (HCFs), but not human umbilical artery endothelial cells. In HUVECs and HUVSMCs, serelaxin increased cAMP, cGMP accumulation and pERK1/2, and the concentration-response curves (CRCs) were bell-shaped. Similar bell-shaped CRCs for cGMP and pERK1/2 were observed in HCFs, whereas in HUASMCs, serelaxin increased cAMP, cGMP and pERK1/2 with sigmoidal CRCs. Gαi/o and lipid raft disruption, but not Gαs inhibition, altered the serelaxin CRC for cAMP and cGMP accumulation in HUVSMC but not HUASMC. Longer term serelaxin exposure increased the expression of neuronal NOS, VEGF, ETβ receptors and MMPs (gelatinases) in RXFP1 receptor-expressing cells. CONCLUSIONS AND IMPLICATIONS Serelaxin caused acute and chronic changes in human umbilical vascular cells that were cell background dependent. Bell-shaped CRCs that were observed only in venous cells and fibroblasts involved Gαi/o located within membrane lipid rafts.
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Affiliation(s)
- M Sarwar
- Drug Discovery Biology, Monash Institute of Pharmacology, Monash University, Melbourne, Vic., Australia
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13
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Bao XC, Fang YQ, You P, Zhang S, Ma J. Protective role of peroxisome proliferator-activated receptor-β/δ against pulmonary oxygen toxicity mediated through changes in NOS expression levels. Exp Lung Res 2014; 40:105-16. [PMID: 24624894 DOI: 10.3109/01902148.2013.879497] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Recent studies have demonstrated that peroxisome proliferator-activated receptor-beta/delta (PPAR-β/δ) has a protective effect during lung injury induced by bleomycin and polymicrobial sepsis, but its function in pulmonary oxygen toxicity is unknown. In this study, we used GW0742, a PPAR-β/δ agonist, and GSK0660, a PPAR-β/δ antagonist, to test the role of PPAR-β/δ in lung injury due to hyperbaric oxygen (HBO2) exposure. Lung injury was induced in rats by HBO2 exposure (2.3 ATA, 100%O2, 8 hours). Sixty male Sprague-Dawley rats were randomly divided into 6 groups: air+vehicle, air+GW0742, air+GSK0660, HBO2+vehicle, HBO2+GW0742, and HBO2+GSK0660. Rats were injected with vehicle or GW0742 (0.3 mg/kg, i.p.) or GSK0660 (1 mg/kg, i.p.) at 1 hour, 6 hours, and 12 hours before either air or oxygen exposure. Administration of GW0742 to rats exposed to HBO2 significantly reduced the observed lung injury, extravascular lung water, total protein levels in bronchoalveolar lavage fluid, and the levels of iNOS and nNOS in the lungs when compared to untreated rats exposed to HBO2. Treatment of rats with GSK0660 exacerbated lung injury and elevated the levels of nNOS and eNOS in the lungs. In addition, nNOS and eNOS knock-out mice were examined. The results indicated that after HBO2 exposure, the lung injury was obviously decreased in the nNOS(-/-)+GSK0660 mice compared to the wild-type +GSK0660 mice; furthermore, administration of GSK0660 significantly elevated the lung injury in the eNOS(-/-) mice. Collectively, these data indicate that PPAR-β/δ activation can protect against pulmonary oxygen toxicity in the lungs of rats through changes in the expression of NOS.
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Affiliation(s)
- Xiao-Chen Bao
- Department of Diving Medicine, Institute of Naval Medical Research , Shanghai , China
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14
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Golub AS, Pittman RN. Bang-bang model for regulation of local blood flow. Microcirculation 2014; 20:455-83. [PMID: 23441827 DOI: 10.1111/micc.12051] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 02/19/2013] [Indexed: 11/27/2022]
Abstract
The classical model of metabolic regulation of blood flow in muscle tissue implies the maintenance of basal tone in arterioles of resting muscle and their dilation in response to exercise and/or tissue hypoxia via the evoked production of vasodilator metabolites by myocytes. A century-long effort to identify specific metabolites responsible for explaining active and reactive hyperemia has not been successful. Furthermore, the metabolic theory is not compatible with new knowledge on the role of physiological radicals (e.g., nitric oxide, NO, and superoxide anion, O2 (-) ) in the regulation of microvascular tone. We propose a model of regulation in which muscle contraction and active hyperemia are considered the physiologically normal state. We employ the "bang-bang" or "on/off" regulatory model which makes use of a threshold and hysteresis; a float valve to control the water level in a tank is a common example of this type of regulation. Active bang-bang regulation comes into effect when the supply of oxygen and glucose exceeds the demand, leading to activation of membrane NADPH oxidase, release of O2 (-) into the interstitial space and subsequent neutralization of the interstitial NO. Switching arterioles on/off when local blood flow crosses the threshold is realized by a local cell circuit with the properties of a bang-bang controller, determined by its threshold, hysteresis, and dead-band. This model provides a clear and unambiguous interpretation of the mechanism to balance tissue demand with a sufficient supply of nutrients and oxygen.
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Affiliation(s)
- Aleksander S Golub
- Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA, USA.
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15
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Mathematical model of wall shear stress-dependent vasomotor response based on physiological mechanisms. Comput Biol Med 2014; 45:126-35. [DOI: 10.1016/j.compbiomed.2013.11.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Revised: 11/18/2013] [Accepted: 11/20/2013] [Indexed: 11/20/2022]
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16
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Beetson KA, Smith SF, Muneer A, Cameron NE, Cotter MA, Cellek S. Vasa Nervorum in Rat Major Pelvic Ganglion are Innervated by Nitrergic Nerve Fibers. J Sex Med 2013; 10:2967-74. [DOI: 10.1111/jsm.12313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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17
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Kar S, Kavdia M. Endothelial NO and O₂·⁻ production rates differentially regulate oxidative, nitroxidative, and nitrosative stress in the microcirculation. Free Radic Biol Med 2013; 63:161-74. [PMID: 23639567 PMCID: PMC4051226 DOI: 10.1016/j.freeradbiomed.2013.04.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 04/04/2013] [Accepted: 04/13/2013] [Indexed: 02/07/2023]
Abstract
Endothelial dysfunction causes an imbalance in endothelial NO and O₂·⁻ production rates and increased peroxynitrite formation. Peroxynitrite and its decomposition products cause multiple deleterious effects including tyrosine nitration of proteins, superoxide dismutase (SOD) inactivation, and tissue damage. Studies have shown that peroxynitrite formation during endothelial dysfunction is strongly dependent on the NO and O₂·⁻ production rates. Previous experimental and modeling studies examining the role of NO and O₂·⁻ production imbalance on peroxynitrite formation showed different results in biological and synthetic systems. However, there is a lack of quantitative information about the formation and biological relevance of peroxynitrite under oxidative, nitroxidative, and nitrosative stress conditions in the microcirculation. We developed a computational biotransport model to examine the role of endothelial NO and O₂·⁻ production on the complex biochemical NO and O₂·⁻ interactions in the microcirculation. We also modeled the effect of variability in SOD expression and activity during oxidative stress. The results showed that peroxynitrite concentration increased with increase in either O₂·⁻ to NO or NO to O₂·⁻ production rate ratio (QO₂·⁻/QNO or QNO/QO₂·⁻, respectively). The peroxynitrite concentrations were similar for both production rate ratios, indicating that peroxynitrite-related nitroxidative and nitrosative stresses may be similar in endothelial dysfunction or inducible NO synthase (iNOS)-induced NO production. The endothelial peroxynitrite concentration increased with increase in both QO₂·⁻/QNO and QNO/QO₂·⁻ ratios at SOD concentrations of 0.1-100 μM. The absence of SOD may not mitigate the extent of peroxynitrite-mediated toxicity, as we predicted an insignificant increase in peroxynitrite levels beyond QO₂·⁻/QNO and QNO/QO₂·⁻ ratios of 1. The results support the experimental observations of biological systems and show that peroxynitrite formation increases with increase in either NO or O₂·⁻ production, and excess NO production from iNOS or from NO donors during oxidative stress conditions does not reduce the extent of peroxynitrite mediated toxicity.
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Affiliation(s)
- Saptarshi Kar
- Department of Biomedical Engineering, Wayne State University, Detroit, MI 48202, USA.
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18
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Shabeeh H, Seddon M, Brett S, Melikian N, Casadei B, Shah AM, Chowienczyk P. Sympathetic activation increases NO release from eNOS but neither eNOS nor nNOS play an essential role in exercise hyperemia in the human forearm. Am J Physiol Heart Circ Physiol 2013; 304:H1225-30. [PMID: 23436331 DOI: 10.1152/ajpheart.00783.2012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nitric oxide (NO) release from endothelial NO synthase (eNOS) and/or neuronal NO synthase (nNOS) could be modulated by sympathetic nerve activity and contribute to increased blood flow after exercise. We examined the effects of brachial-arterial infusion of the nNOS selective inhibitor S-methyl-l-thiocitrulline (SMTC) and the nonselective NOS inhibitor N(G)-monomethyl-l-arginine (l-NMMA) on forearm arm blood flow at rest, during sympathetic activation by lower body negative pressure, and during lower body negative pressure immediately after handgrip exercise. Reduction in forearm blood flow by lower body negative pressure during infusion of SMTC was not significantly different from that during vehicle (-28.5 ± 4.02 vs. -34.1 ± 2.96%, respectively; P = 0.32; n = 8). However, l-NMMA augmented the reduction in forearm blood flow by lower body negative pressure (-44.2 ± 3.53 vs. -23.4 ± 5.71%; n = 8; P < 0.01). When lower body negative pressure was continued after handgrip exercise, there was no significant effect of either l-NMMA or SMTC on forearm blood flow immediately after low-intensity exercise (P = 0.91 and P = 0.44 for l-NMMA vs. saline and SMTC vs. saline, respectively; each n = 10) or high-intensity exercise (P = 0.46 and P = 0.68 for l-NMMA vs. saline and SMTC vs. saline, respectively; each n = 10). These results suggest that sympathetic activation increases NO release from eNOS, attenuating vasoconstriction. Dysfunction of eNOS could augment vasoconstrictor and blood pressure responses to sympathetic activation. However, neither eNOS nor nNOS plays an essential role in postexercise hyperaemia, even in the presence of increased sympathetic activation.
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Affiliation(s)
- Husain Shabeeh
- King's College London British Heart Foundation Centre, London, United Kingdom
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19
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Yamazaki Y, Kondo Y, Kamiyama Y. Estimation of shear-stress-induced endothelial nitric oxide production from flow-mediated dilation. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2013:4521-4524. [PMID: 24110739 DOI: 10.1109/embc.2013.6610552] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Vascular endothelial function assessment yields important diagnostic and prognostic information on patients with (or at risk of) cardiovascular diseases. Flow-mediated dilation (FMD) is the most widely used noninvasive method for assessing the endothelial function. In this method, the magnitude of FMD is used as a surrogate marker for the endothelial function. However, because vasodilation is affected by several other factors as well, the details of how this marker represents the endothelial function are not fully understood. Previously, we developed a mathematical model for vasodilation with intra- and intercellular pathways. In this study, we estimated the shear-stress-induced endothelial nitric oxide production from FMD measurements using the model. The results suggested that the accuracy of the estimated endothelial function obeys the characteristics of the shear stress added to the vascular wall. Furthermore, we showed that the FMD response describes not only the endothelial function but also vascular wall characteristics.
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20
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Kar S, Bhandar B, Kavdia M. Impact of SOD in eNOS uncoupling: a two-edged sword between hydrogen peroxide and peroxynitrite. Free Radic Res 2012; 46:1496-513. [PMID: 22998079 DOI: 10.3109/10715762.2012.731052] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In endothelial cell dysfunction, the uncoupling of eNOS results in higher superoxide (O(2)(•-)) and lower NO production and a reduction in NO availability. Superoxide reacts with NO to form a potent oxidizing agent peroxynitrite (ONOO(-)) resulting in nitrosative and nitroxidative stresses and dismutates to form hydrogen peroxide. Studies have shown superoxide dismutase (SOD) plays an important role in reduction of O(2)(•-) and ONOO(-) during eNOS uncoupling. However, the administration or over-expression of SOD was ineffective or displayed deleterious effects in some cases. An understanding of interactions of the two enzyme systems eNOS and SOD is important in determining endothelial cell function. We analyzed complex biochemical interactions involving eNOS and SOD in eNOS uncoupling. A computational model of biochemical pathway of the eNOS-related NO and O(2)(•-) production and downstream reactions involving NO, O(2)(•-), ONOO(-), H(2)O(2) and SOD was developed. The effects of SOD concentration on the concentration profiles of NO, O(2)(•-), ONOO(-) and H(2)O(2) in eNOS coupling/uncoupling were investigated. The results include (i) SOD moderately improves NO production and concentration during eNOS uncoupling, (ii) O(2)(•-) production rate is independent of SOD concentration, (iii) Increase in SOD concentration from 0.1 to 100 μM reduces O(2)(•-) concentration by 90% at all [BH(4)]/[TBP] ratios, (iv) SOD reduces ONOO(-) concentration and increases H(2)O(2) concentration during eNOS uncoupling, (v) Catalase can reduce H(2)O(2) concentration and (vi) Dismutation rate by SOD is the most sensitive parameter during eNOS uncoupling. Thus, SOD plays a dual role in eNOS uncoupling as an attenuator of nitrosative/nitroxidative stress and an augmenter of oxidative stress.
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Affiliation(s)
- Saptarshi Kar
- Department of Biomedical Engineering, Wayne State University, Detroit, MI, USA.
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21
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Hirai DM, Copp SW, Holdsworth CT, Ferguson SK, Musch TI, Poole DC. Effects of neuronal nitric oxide synthase inhibition on microvascular and contractile function in skeletal muscle of aged rats. Am J Physiol Heart Circ Physiol 2012; 303:H1076-84. [PMID: 22923618 DOI: 10.1152/ajpheart.00477.2012] [Citation(s) in RCA: 8] [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
Advanced age is associated with derangements in skeletal muscle microvascular function during the transition from rest to contractions. We tested the hypothesis that, contrary to what was reported previously in young rats, selective neuronal nitric oxide (NO) synthase (nNOS) inhibition would result in attenuated or absent alterations in skeletal muscle microvascular oxygenation (Po(2)(mv)), which reflects the matching between muscle O(2) delivery and utilization, following the onset of contractions in old rats. Spinotrapezius muscle blood flow (radiolabeled microspheres), Po(2)(mv) (phosphorescence quenching), O(2) utilization (Vo(2); Fick calculation), and submaximal force production were measured at rest and following the onset of contractions in anesthetized old male Fischer 344 × Brown Norway rats (27 to 28 mo) pre- and postselective nNOS inhibition (2.1 μmol/kg S-methyl-l-thiocitrulline; SMTC). At rest, SMTC had no effects on muscle blood flow (P > 0.05) but reduced Vo(2) by ∼23% (P < 0.05), which elevated basal Po(2)(mv) by ∼18% (P < 0.05). During contractions, steady-state muscle blood flow, Vo(2), Po(2)(mv), and force production were not altered after SMTC (P > 0.05 for all). The overall Po(2)(mv) dynamics following onset of contractions was also unaffected by SMTC (mean response time: pre, 19.7 ± 1.5; and post, 20.0 ± 2.0 s; P > 0.05). These results indicate that the locus of nNOS-derived NO control in skeletal muscle depends on age and metabolic rate (i.e., rest vs. contractions). Alterations in nNOS-mediated regulation of contracting skeletal muscle microvascular function with aging may contribute to poor exercise capacity in this population.
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Affiliation(s)
- Daniel M Hirai
- Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas 66506-5802, USA
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22
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Weiss JW, Liu Y, Li X, Ji ES. Nitric oxide and obstructive sleep apnea. Respir Physiol Neurobiol 2012; 184:192-6. [PMID: 22951245 DOI: 10.1016/j.resp.2012.08.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 08/11/2012] [Accepted: 08/13/2012] [Indexed: 01/31/2023]
Abstract
Obstructive sleep apnea is a common disease, affecting 16% of the working age population. Although sleep apnea has a well-established connection to daytime sleepiness presumably mediated through repetitive sleep disruption, some other consequences are less well understood. Clinical, epidemiological, and physiological investigations have demonstrated a connection between sleep apnea and daytime hypertension. The elevation of arterial pressure is evident during waking, when patients are not hypoxic, and is mediated by sustained sympathoexcitation and by altered peripheral vascular reactivity. This review summarizes data suggesting that both the sympathoexcitation and the altered vascular reactivity are, at least in part, a consequence of reduced expression of nitric oxide synthase, in neural tissue and in endothelium. Reduced nitric oxide generation in central and peripheral sites of sympathoregulation and in endothelium together may, in part, explain the elevations in waking pressures observed in sleep apnea patients.
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Affiliation(s)
- J Woodrow Weiss
- Division of Pulmonary, Critical Care, & Sleep Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215, United States.
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23
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Kar S, Kavdia M. Local oxidative and nitrosative stress increases in the microcirculation during leukocytes-endothelial cell interactions. PLoS One 2012; 7:e38912. [PMID: 22719984 PMCID: PMC3375306 DOI: 10.1371/journal.pone.0038912] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 05/15/2012] [Indexed: 11/18/2022] Open
Abstract
Leukocyte-endothelial cell interactions and leukocyte activation are important factors for vascular diseases including nephropathy, retinopathy and angiopathy. In addition, endothelial cell dysfunction is reported in vascular disease condition. Endothelial dysfunction is characterized by increased superoxide (O2•−) production from endothelium and reduction in NO bioavailability. Experimental studies have suggested a possible role for leukocyte-endothelial cell interaction in the vessel NO and peroxynitrite levels and their role in vascular disorders in the arterial side of microcirculation. However, anti-adhesion therapies for preventing leukocyte-endothelial cell interaction related vascular disorders showed limited success. The endothelial dysfunction related changes in vessel NO and peroxynitrite levels, leukocyte-endothelial cell interaction and leukocyte activation are not completely understood in vascular disorders. The objective of this study was to investigate the role of endothelial dysfunction extent, leukocyte-endothelial interaction, leukocyte activation and superoxide dismutase therapy on the transport and interactions of NO, O2•− and peroxynitrite in the microcirculation. We developed a biotransport model of NO, O2•− and peroxynitrite in the arteriolar microcirculation and incorporated leukocytes-endothelial cell interactions. The concentration profiles of NO, O2•− and peroxynitrite within blood vessel and leukocytes are presented at multiple levels of endothelial oxidative stress with leukocyte activation and increased superoxide dismutase accounted for in certain cases. The results showed that the maximum concentrations of NO decreased ∼0.6 fold, O2•− increased ∼27 fold and peroxynitrite increased ∼30 fold in the endothelial and smooth muscle region in severe oxidative stress condition as compared to that of normal physiologic conditions. The results show that the onset of endothelial oxidative stress can cause an increase in O2•− and peroxynitrite concentration in the lumen. The increased O2•− and peroxynitrite can cause leukocytes priming through peroxynitrite and leukocytes activation through secondary stimuli of O2•− in bloodstream without endothelial interaction. This finding supports that leukocyte rolling/adhesion and activation are independent events.
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Affiliation(s)
- Saptarshi Kar
- Department of Biomedical Engineering, Wayne State University, Detroit, Michigan, United States of America.
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24
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Chakrabarti S, Chan CK, Jiang Y, Davidge ST. Neuronal nitric oxide synthase regulates endothelial inflammation. J Leukoc Biol 2012; 91:947-56. [DOI: 10.1189/jlb.1011513] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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25
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Atochin DN, Huang PL. Role of endothelial nitric oxide in cerebrovascular regulation. Curr Pharm Biotechnol 2012; 12:1334-42. [PMID: 21235451 DOI: 10.2174/138920111798280974] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2010] [Revised: 07/01/2010] [Accepted: 08/08/2010] [Indexed: 11/22/2022]
Abstract
Endothelial nitric oxide (NO) plays important roles in the vascular system. Animal models that show vascular dysfunction demonstrate the protective role of endothelial NO dependent pathways. This review focuses on the role of endothelial NO in the regulation of cerebral blood flow and vascular tone. We will discuss the importance of NO in cerebrovascular function using animal models with altered endothelial NO production under normal, ischemic and reperfusion conditions, as well as in hyperoxia. Pharmacological and genetic manipulations of the endothelial NO system demonstrate the essential roles of endothelial NO synthase in maintenance of vascular tone and cerebral perfusion under normal and pathological conditions.
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Affiliation(s)
- Dmitriy N Atochin
- Cardiovascular Research Center and Cardiology Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02129, USA.
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26
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McLeod DS, Baba T, Bhutto IA, Lutty GA. Co-expression of endothelial and neuronal nitric oxide synthases in the developing vasculatures of the human fetal eye. Graefes Arch Clin Exp Ophthalmol 2012; 250:839-48. [PMID: 22411126 DOI: 10.1007/s00417-012-1969-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 01/15/2012] [Accepted: 02/10/2012] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Nitric oxide (NO) is a multifunctional gaseous molecule that regulates various physiological functions in both neuronal and non-neuronal cells. NO is synthesized by nitric oxide synthases (NOSs), of which three isoforms have been identified. Neuronal NOS (nNOS) and endothelial NOS (eNOS) constitutively produce low levels of NO as a cell-signaling molecule in response to an increase in intracellular calcium concentration. Recent data have revealed a predominant role of eNOS in both angiogenesis and vasculogenesis. METHODS The immunohistochemical localization of nNOS and eNOS was investigated during embryonic and fetal ocular vascular development from 7 to 21 weeks gestation (WG) on sections of cryopreserved tissue. RESULTS eNOS was confined to endothelial cells of developing vessels at all ages studied. nNOS was prominent in nuclei of vascular endothelial and smooth muscle cells in the fetal vasculature of vitreous and choriocapillaris. nNOS was also prominent in the nuclei of CXCR4(+) progenitors in the inner retina and inner neuroblastic layer. CONCLUSIONS These findings demonstrate co-expression of n- and eNOS isoforms in different compartments of vasoformative cells during development. Nuclear nNOS was present in vascular and nonvascular progenitors as well as endothelial cells and pericytes. This suggests that nNOS may play a role in the transcription regulatory systems in endothelial cells and pericytes during ocular hemo-vasculogenesis, vasculogenesis, and angiogenesis.
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Affiliation(s)
- D Scott McLeod
- Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, M041 Smith Research Building, 400 North Broadway, Baltimore, MD 21287, USA
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Møllerløkken A, Gaustad SE, Havnes MB, Gutvik CR, Hjelde A, Wisløff U, Brubakk AO. Venous gas embolism as a predictive tool for improving CNS decompression safety. Eur J Appl Physiol 2012; 112:401-9. [PMID: 21594696 PMCID: PMC3258401 DOI: 10.1007/s00421-011-1998-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Accepted: 05/02/2011] [Indexed: 11/30/2022]
Abstract
A key process in the pathophysiological steps leading to decompression sickness (DCS) is the formation of inert gas bubbles. The adverse effects of decompression are still not fully understood, but it seems reasonable to suggest that the formation of venous gas emboli (VGE) and their effects on the endothelium may be the central mechanism leading to central nervous system (CNS) damage. Hence, VGE might also have impact on the long-term health effects of diving. In the present review, we highlight the findings from our laboratory related to the hypothesis that VGE formation is the main mechanism behind serious decompression injuries. In recent studies, we have determined the impact of VGE on endothelial function in both laboratory animals and in humans. We observed that the damage to the endothelium due to VGE was dose dependent, and that the amount of VGE can be affected both by aerobic exercise and exogenous nitric oxide (NO) intervention prior to a dive. We observed that NO reduced VGE during decompression, and pharmacological blocking of NO production increased VGE formation following a dive. The importance of micro-nuclei for the formation of VGE and how it can be possible to manipulate the formation of VGE are discussed together with the effects of VGE on the organism. In the last part of the review we introduce our thoughts for the future, and how the enigma of DCS should be approached.
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Affiliation(s)
- A Møllerløkken
- Baromedical and Environmental Physiology Group, Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Medisinsk teknisk forskningssenter, Olav Kyrres gt 9, 7489, Trondheim, Norway.
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Deonikar P, Kavdia M. Low micromolar intravascular cell-free hemoglobin concentration affects vascular NO bioavailability in sickle cell disease: a computational analysis. J Appl Physiol (1985) 2012; 112:1383-92. [PMID: 22223452 DOI: 10.1152/japplphysiol.01173.2011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In sickle cell disease, the changes in RBC morphology destabilize the red blood cell (RBC) membrane and lead to hemolysis. Several experimental and clinical studies have associated intravascular hemolysis with pulmonary hypertension in sickle cell disease. Cell-free hemoglobin (Hb) from intravascular hemolysis has high affinity for nitrixc oxide (NO) and can affect the NO bioavailability in the sickle cell disease, which may eventually lead to pulmonary hypertension. To study the effects of intravascular hemolysis related cell-free Hb concentrations on NO bioavailability, we developed a two-dimensional mathematical model of NO biotransport in 50-μm arteriole under steady-state sickle cell disease conditions. We analyzed the effects of flow-dependent NO production and axial and radial transport of NO, a recently reported much lower NO-RBC reaction rate constant, and cell-free layer thickness on NO biotransport. Our results show that the presence of cell-free Hb concentrations as low as 0.5 μM results in an approximately three- to sevenfold reduction in the predicted smooth muscle cell NO concentrations compared with those under physiological conditions. In addition, increasing the diffusional resistance for NO in vascular lumen from cell-free layer or reducing NO-RBC reaction rate did not improve the NO bioavailability at the smooth muscle cell layer significantly for cell-free Hb concentrations ≥1 μM. These results suggest that lower NO bioavailability due to low micromolar cell-free Hb can disturb NO homeostasis and cause insufficient bioavailability at the smooth muscle cell layer. Our results supports the hypothesis that hemolysis-associated reduction in NO bioavailability may play a role in the development of pathophysiological complications like pulmonary hypertension in sickle cell disease that are observed in several clinical and experimental studies.
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Affiliation(s)
- Prabhakar Deonikar
- Department of Biomedical Engineering, Wayne State University, 5050 Anthony Wayne Dr., Detroit, MI 48202, USA.
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Hama-Tomioka K, Kinoshita H, Nakahata K, Kondo T, Azma T, Kawahito S, Hatakeyama N, Matsuda N. Roles of neuronal nitric oxide synthase, oxidative stress, and propofol in N -methyl- d -aspartate-induced dilatation of cerebral arterioles. Br J Anaesth 2012; 108:21-9. [DOI: 10.1093/bja/aer368] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
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Royal CR, Ma H, Walker R, White RE. Estrogen signaling in microvascular arteries: parturition reduces vasodilation by reducing 17β-estradiol and nNOS. Steroids 2011; 76:991-7. [PMID: 21458475 PMCID: PMC3139781 DOI: 10.1016/j.steroids.2011.03.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 03/18/2011] [Accepted: 03/24/2011] [Indexed: 12/28/2022]
Abstract
Few studies have examined the potential effects of childbirth on the responses of the female vasculature--especially the resistance microvasculature of non-reproductive tissues. In the present study we have investigated the response of mesenteric microvascular resistance vessels to estrogen (E2), an important vasoactive hormone. Vessels were obtained from either nulliparous or postpartum female Sprague-Dawley rats, and isometric tension studies were performed. We found that E2 induced a concentration-dependent, endothelium-independent relaxation of microvessels precontracted with 10(-5) M phenylephrine; however, E2-induced relaxation was reduced by nearly half in vessels from postpartum animals compared to nulliparous controls. Inhibiting nitric oxide synthase activity with 10(-4) M L-NMMA or L-NPA (which exhibits selectivity for type 1 or nNOS) attenuated the relaxation effect of E2 on arteries from nulliparous animals. In contrast, L-NPA had little effect on arteries from postpartum animals, suggesting a reduced influence of nNOS after parturition. Moreover, expression of nNOS protein in microvessels was decreased 39% in the postpartum state compared to arteries from nulliparous animals. We propose that the impaired E2-induced relaxation response of microvessels from postpartum animals reflects a downregulation of NO production due to lower nNOS expressed in vascular smooth muscle cells. We measured a 73% decrease in serum E2 levels in the postpartum state compared to nulliparous animals. Because E2 has been shown to increase nNOS protein expression, we propose that lower E2 levels after parturition decrease expression of nNOS, leading to a reduced vasodilatory capacity of resistance microvessels.
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Affiliation(s)
- Crista R. Royal
- Department of Pharmacology & Toxicology, Medical College of Georgia, Georgia Health Sciences University, Augusta, GA 30912
| | - Handong Ma
- Department of Pharmacology & Toxicology, Medical College of Georgia, Georgia Health Sciences University, Augusta, GA 30912
| | - Richard Walker
- Department of Biostatistics, Georgia Health Sciences University, Augusta, GA 30912
| | - Richard E. White
- Department of Pharmacology & Toxicology, Medical College of Georgia, Georgia Health Sciences University, Augusta, GA 30912
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Stewart JM, Nafday A, Ocon AJ, Terilli C, Medow MS. Cutaneous constitutive nitric oxide synthase activation in postural tachycardia syndrome with splanchnic hyperemia. Am J Physiol Heart Circ Physiol 2011; 301:H704-11. [PMID: 21642500 DOI: 10.1152/ajpheart.00171.2011] [Citation(s) in RCA: 9] [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
Models of microgravity are linked to excessive constitutive nitric oxide (NO) synthase (NOS), splanchnic vasodilation, and orthostatic intolerance. Normal-flow postural tachycardia syndrome (POTS) is a form of chronic orthostatic intolerance associated with splanchnic hyperemia. To test the hypothesis that there is excessive constitutive NOS in POTS, we determined whether cutaneous microvascular neuronal NO and endothelial NO are increased. We performed two sets of experiments in POTS and control subjects aged 21.4 ± 2 yr. We used laser-Doppler flowmetry to measure the cutaneous response to local heating as an indicator of bioavailable neuronal NO. To test for bioavailable endothelial NO, we infused intradermal acetylcholine through intradermal microdialysis catheters and used the selective neuronal NOS inhibitor l-N(ω)-nitroarginine-2,4-L-diamino-butyric amide (N(ω), 10 mM), the selective inducible NOS inhibitor aminoguanidine (10 mM), the nonspecific NOS inhibitor nitro-l-arginine (NLA, 10 mM), or Ringer solution. The acetylcholine dose response and the NO-dependent plateau of the local heating response were increased in POTS compared with those in control subjects. The local heating plateau was significantly higher, 98 ± 1%maximum cutaneous vascular conductance (%CVC(max)) in POTS compared with 88 ± 2%CVC(max) in control subjects but decreased to the same level with N(ω) (46 ± 5%CVC(max) in POTS compared with 49 ± 4%CVC(max) in control) or with NLA (45 ± 3%CVC(max) in POTS compared with 47 ± 4%CVC(max) in control). Only NLA blunted the acetylcholine dose response, indicating that NO produced by endothelial NOS was released by acetylcholine. Aminoguanidine was without effect. This is consistent with increased endothelial and neuronal NOS activity in normal-flow POTS.
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Affiliation(s)
- Julian M Stewart
- Department of Pediatrics, New York Medical College, Valhalla, New York, New York, USA.
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Liang JQ, Wu K, Jia ZH, Liu C, Ding J, Huang SN, Yin PP, Wu XC, Wei C, Wu YL, Wang HY. Chinese medicine Tongxinluo modulates vascular endothelial function by inducing eNOS expression via the PI-3K/Akt/HIF-dependent signaling pathway. JOURNAL OF ETHNOPHARMACOLOGY 2011; 133:517-523. [PMID: 20969943 DOI: 10.1016/j.jep.2010.10.031] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 09/21/2010] [Accepted: 10/13/2010] [Indexed: 05/30/2023]
Abstract
AIM OF THE STUDY To investigate the molecular mechanisms whereby the Chinese medicinal compound Tongxinluo improves vascular endothelial function through studying the induction of endothelial nitric oxide synthase (eNOS) and its upstream signaling pathway. MATERIALS AND METHODS Hyperhomocysteinemia was induced in Wistar rats by a methionine-rich diet followed by Tongxinluo treatment. The aorta ring was isolated for measuring vascular dilation of aorta and eNOS expression. Human umbilical vein endothelial cells (HUVECs) were transfected with AP-1, NF-κB, HRE or eNOS reporter plasmid followed by Tongxinluo exposure. Expression of the reporter genes was measured by luciferase assay. The level of eNOS was studied by western blot and the nitric oxide content was measured using the nitrate reductase method. HUVECs were also transiently transfected with the dominant negative mutant of HIF-1, PI-3K or Akt to explore the role of HIF and PI-3K/Akt pathway in eNOS induction by Tongxinluo. RESULTS Tongxinluo could significantly up-regulate the expression of eNOS in the aortic tissue and improve the endothelium-dependent vasodilation of the aorta ring. Additionally, Tongxinluo at various doses could significantly enhance the expression of HRE and eNOS reporter gene as well as up-regulate the protein level of eNOS. Meanwhile, Tongxinluo caused a dose-dependent increase in the NO content in the supernatant of HUVECs. Suppression of HIF-1 activation by DN-HIF or inhibition of PI-3K/Akt pathway by ΔP85 or DN-Akt both attenuated HRE reporter gene activation and eNOS induction by Tongxinluo. CONCLUSION Tongxinluo, a compound Chinese traditional medicine, up-regulates the expression of eNOS via the PI-3K/Akt/HIF-dependent signaling pathway, thus improving the endothelium-dependent vasodilation.
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Affiliation(s)
- Jun Qing Liang
- The International Cooperation Laboratory on Signal Transduction of Eastern Hepatobiliary Surgery Institute, Second Military Medical University, 225 Changhai Road, Shanghai 200438, China
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Deonikar P, Kavdia M. A computational model for nitric oxide, nitrite and nitrate biotransport in the microcirculation: effect of reduced nitric oxide consumption by red blood cells and blood velocity. Microvasc Res 2010; 80:464-76. [PMID: 20888842 DOI: 10.1016/j.mvr.2010.09.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 09/17/2010] [Accepted: 09/17/2010] [Indexed: 11/19/2022]
Abstract
Bioavailability of vasoactive endothelium-derived nitric oxide (NO) in vasculature is a critical factor in regulation of many physiological processes. Consumption of NO by RBC plays a crucial role in maintaining NO bioavailability. Recently, Deonikar and Kavdia (2009b) reported an effective NO-RBC reaction rate constant of 0.2×10(5)M(-1)s(-1) that is ~7 times lower than the commonly used NO-RBC reaction rate constant of 1.4×10(5)M(-1)s(-1). To study the effect of lower NO-RBC reaction rate constant and nitrite and nitrate formation (products of NO metabolism in blood), we developed a 2D mathematical model of NO biotransport in 50 and 200μm ID arterioles to calculate NO concentration in radial and axial directions in the vascular lumen and vascular wall of the arterioles. We also simulated the effect of blood velocity on NO distribution in the arterioles to determine whether NO can be transported to downstream locations in the arteriolar lumen. The results indicate that lowering the NO-RBC reaction rate constant increased the NO concentration in the vascular lumen as well as the vascular wall. Increasing the velocity also led to increase in NO concentration. We predict increased NO concentration gradient along the axial direction with an increase in the velocity. The predicted NO concentration was 281-1163nM in the smooth muscle cell layer for 50μm arteriole over the blood velocity range of 0.5-4cms(-1) for k(NO-RBC) of 0.2×10(5)M(-1)s(-1), which is much higher than the reported values from earlier mathematical modeling studies. The NO concentrations are similar to the experimentally measured vascular wall NO concentration range of 300-1000nM in several different vascular beds. The results are significant from the perspective that the downstream transport of NO is possible under the right circumstances.
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Affiliation(s)
- Prabhakar Deonikar
- Department of Biomedical Engineering, Wayne State University, Detroit, MI 48202, USA
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Kajimura M, Fukuda R, Bateman RM, Yamamoto T, Suematsu M. Interactions of multiple gas-transducing systems: hallmarks and uncertainties of CO, NO, and H2S gas biology. Antioxid Redox Signal 2010; 13:157-92. [PMID: 19939208 PMCID: PMC2925289 DOI: 10.1089/ars.2009.2657] [Citation(s) in RCA: 219] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The diverse physiological actions of the "biologic gases," O2, CO, NO, and H2S, have attracted much interest. Initially viewed as toxic substances, CO, NO, and H2S play important roles as signaling molecules. The multiplicity of gas actions and gas targets and the difficulty in measuring local gas concentrations obscures detailed mechanisms whereby gases exert their actions, and many questions remain unanswered. It is now readily apparent, however, that heme-based proteins play central roles in gas-generation/reception mechanisms and provide a point where multiple gases can interact. In this review, we consider a number of key issues related to "gas biology," including the effective tissue concentrations of these gases and the importance and significance of the physical proximity of gas-producing and gas-receptor/sensors. We also take an integrated approach to the interaction of gases by considering the physiological significance of CO, NO, and H2S on mitochondrial cytochrome c oxidase, a key target and central mediator of mitochondrial respiration. Additionally, we consider the effects of biologic gases on mitochondrial biogenesis and "suspended animation." By evaluating gas-mediated control functions from both in vitro and in vivo perspectives, we hope to elaborate on the complex multiple interactions of O2, NO, CO, and H2S.
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Affiliation(s)
- Mayumi Kajimura
- Department of Biochemistry and Integrative Medical Biology, School of Medicine, Keio University , Tokyo, Japan.
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Unverdorben M, von Holt K, Winkelmann BR. Smoking and atherosclerotic cardiovascular disease: part II: role of cigarette smoking in cardiovascular disease development. Biomark Med 2010; 3:617-53. [PMID: 20477529 DOI: 10.2217/bmm.09.51] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Potential mechanisms and biomarkers of atherosclerosis related to cigarette smoking - a modifiable risk factor for that disease - are discussed in this article. These include smoking-associated inflammatory markers, such as leukocytes, high-sensitivity C-reactive protein, serum amyloid A, ICAM-1 and IL-6. Other reviewed markers are indicative for smoking-related impairment of arterial endothelial function (transcapillary leakage of albumin, inhibition of endogenous nitric oxide synthase activity and reduced endothelium-dependent vasodilation) or point to oxidative stress caused by various chemicals (cholesterol oxidation, autoantibodies to oxidized low-density lipoprotein, plasma levels of malondialdehyde and F(2)-isoprostanes and reduced antioxidant capacity). Smoking enhances platelet aggregability, increases blood viscosity and shifts the pro- and antithrombotic balance towards increased coagulability (e.g., fibrinogen, von Willebrand factor, ICAM-1 and P-selectin). Insulin resistance is higher in smokers compared with nonsmokers, and hemoglobin A1c is dose-dependently elevated, as is homocysteine. Smoke exposure may influence the kinetics of markers with different response to transient or chronic changes in cigarette smoking behavior.
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Affiliation(s)
- Martin Unverdorben
- Clinical Research Institute, Center for Cardiovascular Diseases, Heinz-Meise-Strasse 100, 36199 Rotenburg an der Fulda, Germany.
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Edwards A, Layton AT. Nitric oxide and superoxide transport in a cross section of the rat outer medulla. II. Reciprocal interactions and tubulovascular cross talk. Am J Physiol Renal Physiol 2010; 299:F634-47. [PMID: 20519375 DOI: 10.1152/ajprenal.00681.2009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In a companion study (Edwards A and Layton AT. Am J Physiol Renal Physiol. doi:10.1152/ajprenal.00680.2009), we developed a mathematical model of nitric oxide (NO), superoxide (O(2)(-)), and total peroxynitrite (ONOO) transport in mid-outer stripe and mid-inner stripe cross sections of the rat outer medulla (OM). We examined how the three-dimensional architecture of the rat OM, together with low medullary oxygen tension (Po(2)), affects the distribution of NO, O(2)(-), and ONOO in the rat OM. In the current study, we sought to determine generation rate and permeability values that are compatible with measurements of medullary NO concentrations and to assess the importance of tubulovascular cross talk and NO-O(2)(-) interactions under physiological conditions. Our results suggest that the main determinants of NO concentrations in the rat OM are the rate of vascular and tubular NO synthesis under hypoxic conditions, and the red blood cell (RBC) permeability to NO (P(NO)(RBC)). The lower the P(NO)(RBC), the lower the amount of NO that is scavenged by hemoglobin species, and the higher the extra-erythrocyte NO concentrations. In addition, our results indicate that basal endothelial NO production acts to significantly limit NaCl reabsorption across medullary thick ascending limbs and to sustain medullary perfusion, whereas basal epithelial NO production has a smaller impact on NaCl transport and a negligible effect on vascular tone. Our model also predicts that O(2)(-) consumption by NO significantly reduces medullary O(2)(-) concentrations, but that O(2)(-) , when present at subnanomolar concentrations, has a small impact on medullary NO bioavailability.
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Affiliation(s)
- Aurélie Edwards
- Department of Chemical and Biological Engineering, Tufts University, Medford, Massachusetts 02155, USA.
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Ikeyama K, Denda S, Tsutsumi M, Denda M. Neuronal Nitric Oxide Synthase in Epidermis Is Involved in Cutaneous Circulatory Response to Mechanical Stimulation. J Invest Dermatol 2010; 130:1158-66. [DOI: 10.1038/jid.2009.350] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Copp SW, Hirai DM, Schwagerl PJ, Musch TI, Poole DC. Effects of neuronal nitric oxide synthase inhibition on resting and exercising hindlimb muscle blood flow in the rat. J Physiol 2010; 588:1321-31. [PMID: 20176629 DOI: 10.1113/jphysiol.2009.183723] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Nitric oxide (NO) derived from endothelial NO synthase (eNOS) is an integral mediator of vascular control during muscle contractions. However, it is not known whether neuronal NOS (nNOS)-derived NO regulates tissue hyperaemia in healthy subjects, particularly during exercise. We tested the hypothesis that selective nNOS inhibition would reduce blood flow and vascular conductance (VC) in rat hindlimb locomotor muscle(s), kidneys and splanchnic organs at rest and during dynamic treadmill exercise (20 m min(-1), 10% grade). Nineteen male Sprague-Dawley rats (555 +/- 23 g) were assigned to either rest (n = 9) or exercise (n = 10) groups. Blood flow and VC were determined via radiolabelled microspheres before and after the intra-arterial administration of the selective nNOS inhibitor S-methyl-L-thiocitrulline (SMTC, 2.1 +/- 0.1 micromol kg(-1)). Total hindlimb muscle blood flow (control: 20 +/- 2 ml min(-1) 100g(-1), SMTC: 12 +/- 2 ml min(-1) 100g(-1), P < 0.05) and VC (control: 0.16 +/- 0.02 ml min(-1) 100 g(-1) mmHg(1), SMTC: 0.09 +/- 0.01 ml min(-1) 100 g(-1) mmHg(-1), P < 0.05) were reduced substantially at rest. Moreover, the magnitude of the absolute reduction in blood flow and VC correlated (P < 0.05) with the proportion of oxidative muscle fibres found in the individual muscles or muscle parts of the hindlimb. During exercise, total hindlimb blood flow (control: 108 +/- 7 ml min(-1) 100 g(-1), SMTC: 105 +/- 8 ml min(-1) 100 g(-1)) and VC (control: 0.77 +/- 0.06 ml min(-1) 100g(-1) mmHg(-1); SMTC: 0.70 +/- 0.05 ml min(-1) 100g(-1) mmHg(-1)) were not different (P > 0.05) between control and SMTC conditions. SMTC reduced (P < 0.05) blood flow and VC at rest and during exercise in the kidneys, adrenals and liver. These results enhance our understanding of the role of NO-mediated circulatory control by demonstrating that nNOS does not appear to subserve an obligatory role in the exercising muscle hyperaemic response in the rat.
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Affiliation(s)
- Steven W Copp
- Department of Kinesiology, Kansas State University, Manhattan, KS 66506-5802, USA
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Yücel MA, Devor A, Akin A, Boas DA. The Possible Role of CO(2) in Producing A Post-Stimulus CBF and BOLD Undershoot. FRONTIERS IN NEUROENERGETICS 2009; 1:7. [PMID: 20027233 PMCID: PMC2795469 DOI: 10.3389/neuro.14.007.2009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Accepted: 10/08/2009] [Indexed: 12/04/2022]
Abstract
Comprehending the underlying mechanisms of neurovascular coupling is important for understanding the pathogenesis of neurodegenerative diseases related to uncoupling. Moreover, it elucidates the casual relation between the neural signaling and the hemodynamic responses measured with various imaging modalities such as functional magnetic resonance imaging (fMRI). There are mainly two hypotheses concerning this mechanism: a metabolic hypothesis and a neurogenic hypothesis. We have modified recent models of neurovascular coupling adding the effects of both NO (nitric oxide) kinetics, which is a well-known neurogenic vasodilator, and CO2 kinetics as a metabolic vasodilator. We have also added the Hodgkin–Huxley equations relating the membrane potentials to sodium influx through the membrane. Our results show that the dominant factor in the hemodynamic response is NO, however CO2 is important in producing a brief post-stimulus undershoot in the blood flow response that in turn modifies the fMRI blood oxygenation level-dependent post-stimulus undershoot. Our results suggest that increased cerebral blood flow during stimulation causes CO2 washout which then results in a post-stimulus hypocapnia induced vasoconstrictive effect.
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Affiliation(s)
- Meryem A Yücel
- Institute of Biomedical Engineering, Boğaziçi University Istanbul, Turkey
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Deonikar P, Kavdia M. An Integrated Computational and Experimental Model of Nitric Oxide–Red Blood Cell Interactions. Ann Biomed Eng 2009; 38:357-70. [DOI: 10.1007/s10439-009-9823-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Accepted: 10/13/2009] [Indexed: 12/21/2022]
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Kellogg DL, Zhao JL, Wu Y. Roles of nitric oxide synthase isoforms in cutaneous vasodilation induced by local warming of the skin and whole body heat stress in humans. J Appl Physiol (1985) 2009; 107:1438-44. [PMID: 19745188 DOI: 10.1152/japplphysiol.00690.2009] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nitric oxide (NO) participates in the cutaneous vasodilation caused by increased local skin temperature (Tloc) and whole body heat stress in humans. In forearm skin, endothelial NO synthase (eNOS) participates in vasodilation due to elevated Tloc and neuronal NO synthase (nNOS) participates in vasodilation due to heat stress. To explore the relative roles and interactions of these isoforms, we examined the effects of a relatively specific eNOS inhibitor, N(omega)-amino-l-arginine (LNAA), and a specific nNOS inhibitor, N(omega)-propyl-l-arginine (NPLA), both separately and in combination, on skin blood flow (SkBF) responses to increased Tloc and heat stress in two protocols. In each protocol, SkBF was monitored by laser-Doppler flowmetry (LDF) and mean arterial pressure (MAP) by Finapres. Cutaneous vascular conductance (CVC) was calculated (CVC = LDF/MAP). Intradermal microdialysis was used to treat one site with 5 mM LNAA, another with 5 mM NPLA, a third with combined 5 mM LNAA and 5 mM NPLA (Mix), and a fourth site with Ringer only. In protocol 1, Tloc was controlled with combined LDF/local heating units. Tloc was increased from 34 degrees C to 41.5 degrees C to cause local vasodilation. In protocol 2, after a period of normothermia, whole body heat stress was induced (water-perfused suits). At the end of each protocol, all sites were perfused with 58 mM nitroprusside to effect maximal vasodilation for data normalization. In protocol 1, at Tloc = 34 degrees C, CVC did not differ between sites (P > 0.05). LNAA and Mix attenuated CVC increases at Tloc = 41.5 degrees C to similar extents (P < 0.05, LNAA or Mix vs. untreated or NPLA). In protocol 2, in normothermia, CVC did not differ between sites (P > 0.05). During heat stress, NPLA and Mix attenuated CVC increases to similar extents, but no significant attenuation occurred with LNAA (P < 0.05, NPLA or Mix vs. untreated or LNAA). In forearm skin, eNOS mediates the vasodilator response to increased Tloc and nNOS mediates the vasodilator response to heat stress. The two isoforms do not appear to interact during either response.
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Affiliation(s)
- Dean L Kellogg
- Geriatric Research, Education, and Clinical Center, Department of Veterans Affairs, South Texas Veterans Health Care System, Audie L. Murphy Memorial Veterans Hospital Division, Texas, USA.
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Turoni CMJ, de Bruno MP, Coviello A, Marañón RO, Herrera RN, Muntaner J, Proto V. Internal Mammary Artery Grafts Reactivity in Hypertensive Patients: Role of Stretching in Extraendothelial Nitric Oxide. Clin Exp Hypertens 2009; 29:327-44. [PMID: 17653967 DOI: 10.1080/10641960701500570] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND The internal mammary artery (IMA) used in bypass coronary surgery remains efficient for a longer time than other grafts, such as saphenous veins; however, its biological characteristics are incompletely defined. OBJECTIVE To compare in IMA grafts from hypertensive (HT) and normotensive (NT) patients the presence of endothelium and their functionability, the response to passive stretching and basal tone, the reactivity to exogenous vasoconstrictors, the role of stretching in NO release, and the possible extraendothelial NO source. METHODS AND RESULTS IMA rings contractility, presence of endothelium, and nitrite release were studied. An endothelial dysfunction associated with hypertension was found. IMA rings from HT had an impaired response to passive stretching, resulting in a decreased relaxation. All IMA grafts had an increased basal tone demonstrated by relaxation to SNP; however, a lesser response was found in HT. Interestingly, it was demonstrated that NO release was present in IMA grafts, despite an endothelial dysfunction and that stretching increased NO release. This effect was inhibited by Ca2+ -free media, L-NAME and a specific neuronal NO synthase (nNOS) inhibitor. Furthermore, the demonstration of the presence of nNOS in smooth muscle cells by immunohistochemistry supports a role of extraendothelial NO. CONCLUSION We demonstrate the impact of hypertension in IMA grafts producing increased endothelial dysfunction, reduced response to passive stretching, increased basal tone, and impaired responsiveness to exogenous vasoconstrictors and NO release. A specific role of stretching in extraendothelial NO release was demonstrated, which may have an important role in the outcome of IMA grafts due to the protective actions of NO, even in the absence of the endothelium.
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Affiliation(s)
- Claudio M Joo Turoni
- Dpto. Biomédico (Or. Fisiología), Facultad de Medicina, Universidad Nacional de Tucumán, INSIBIO-CONICET, Tucumán, Argentina
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Gundersen SI, Chen G, Palmer AF. Mathematical model of NO and O2 transport in an arteriole facilitated by hemoglobin based O2 carriers. Biophys Chem 2009; 143:1-17. [PMID: 19318228 PMCID: PMC2717632 DOI: 10.1016/j.bpc.2009.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Revised: 02/10/2009] [Accepted: 02/10/2009] [Indexed: 01/01/2023]
Abstract
The increasing demand for donated human blood has spurred research to develop hemoglobin-based O(2) carriers (HBOCs) that can be used as red blood cell (RBC) substitutes. However, in vivo studies of acellular HBOCs have shown an increase in mean arterial pressure following transfusion that has been attributed to the HBOC's ability to scavenge NO (an important vasodilator that is synthesized by endothelial cells in the blood vessel wall that signals neighboring smooth muscle cells to relax). In this study, a mathematical model was developed to describe NO and O(2) transport in an arteriole containing a mixture of acellular HBOCs and RBCs. The acellular HBOCs studied in this work possessed a wide range of O(2) affinities, O(2) dissociation rate constants and NO reactivities in order to evaluate their effect on O(2) tension and NO concentration in the arteriole tissue region. By focusing on the concentration of NO that is localized in the arteriole smooth muscle cell region, the model can predict the vasopressor response of HBOCs. The results of this study confirmed that acellular HBOCs scavenge large amounts of NO from the entire arteriole (approximately 50% or more NO compared to RBCs only). A recombinant Hb, rHb3011, displayed the least NO reactivity and consequently left the most NO remaining in the arteriole. The NO concentration in the arteriole with respect to the other HBOCs studied was proportional to their NO reactivity. Therefore, the results of this study demonstrate that NO scavenging is an unavoidable consequence of transfusing HBOCs. To prevent or reduce vasodilatation, we suggest administration of NO by either inhaling NO or transfusing nitrite into the blood stream followed by transfusion of HBOC.
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Affiliation(s)
- Sharon Irene Gundersen
- The Ohio State University Department of Chemical and Biomolecular Engineering 140 West 19 Avenue Columbus, OH 43210
| | - Guo Chen
- The Ohio State University Department of Chemical and Biomolecular Engineering 140 West 19 Avenue Columbus, OH 43210
| | - Andre Francis Palmer
- The Ohio State University Department of Chemical and Biomolecular Engineering 140 West 19 Avenue Columbus, OH 43210
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Abstract
Blood-flow rate in the normal microcirculation is regulated to meet the metabolic demands of the tissues, which vary widely with position and with time, but is relatively unaffected by changes of arterial pressure over a considerable range. The regulation of blood flow is achieved by the combined effects of multiple interacting mechanisms, including sensitivity to pressure, flow rate, metabolite levels, and neural signals. The main effectors of flow regulation, the arterioles and small arteries, are located at a distance from the regions of tissue that they supply. Flow regulation requires the sensing of metabolic and hemodynamic conditions and the transfer of information about tissue metabolic status to upstream vessels. Theoretical approaches can contribute to the understanding of flow regulation by providing quantitative descriptions of the mechanisms involved, by showing how these mechanisms interact in networks of interconnected microvessels supplying metabolically active tissues, and by establishing relationships between regulatory processes occurring at the microvascular level and variations of metabolic activity and perfusion in whole tissues. Here, a review is presented of previous and current theoretical approaches for investigating the regulation of blood flow in the microcirculation.
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Affiliation(s)
- Timothy W Secomb
- Department of Physiology, University of Arizona, Tucson, Arizona 85724-5051, USA.
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Allen BW, Demchenko IT, Piantadosi CA. Two faces of nitric oxide: implications for cellular mechanisms of oxygen toxicity. J Appl Physiol (1985) 2008; 106:662-7. [PMID: 18845774 DOI: 10.1152/japplphysiol.91109.2008] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recent investigations have elucidated some of the diverse roles played by reactive oxygen and nitrogen species in events that lead to oxygen toxicity and defend against it. The focus of this review is on toxic and protective mechanisms in hyperoxia that have been investigated in our laboratories, with an emphasis on interactions of nitric oxide (NO) with other endogenous chemical species and with different physiological systems. It is now emerging from these studies that the anatomical localization of NO release, which depends, in part, on whether the oxygen exposure is normobaric or hyperbaric, strongly influences whether toxicity emerges and what form it takes, for example, acute lung injury, central nervous system excitation, or both. Spatial effects also contribute to differences in the susceptibility of different cells in organs at risk from hyperoxia, especially in the brain and lungs. As additional nodes are identified in this interactive network of toxic and protective responses, future advances may open up the possibility of novel pharmacological interventions to extend both the time and partial pressures of oxygen exposures that can be safely tolerated. The implications of a better understanding of the mechanisms by which NO contributes to central nervous system oxygen toxicity may include new insights into the pathogenesis of seizures of diverse etiologies. Likewise, improved knowledge of NO-based mechanisms of pulmonary oxygen toxicity may enhance our understanding of other types of lung injury associated with oxidative or nitrosative stress.
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Affiliation(s)
- Barry W Allen
- Duke University Medical Center Center for Hyperbaric Medicine and Environmental Physiology, Durham, NC 27710, USA.
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46
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A Neurovascular Transmission Model for Acupuncture-induced Nitric Oxide. J Acupunct Meridian Stud 2008; 1:42-50. [DOI: 10.1016/s2005-2901(09)60006-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Accepted: 04/14/2008] [Indexed: 11/20/2022] Open
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Chen K, Pittman RN, Popel AS. Nitric oxide in the vasculature: where does it come from and where does it go? A quantitative perspective. Antioxid Redox Signal 2008; 10:1185-98. [PMID: 18331202 PMCID: PMC2932548 DOI: 10.1089/ars.2007.1959] [Citation(s) in RCA: 187] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Nitric oxide (NO) affects two key aspects of O2 supply and demand: It regulates vascular tone and blood flow by activating soluble guanylate cyclase (sGC) in the vascular smooth muscle, and it controls mitochondrial O2 consumption by inhibiting cytochrome c oxidase. However, significant gaps exist in our quantitative understanding of the regulation of NO production in the vascular region. Large apparent discrepancies exist among the published reports that have analyzed the various pathways in terms of the perivascular NO concentration, the efficacy of NO in causing vasodilation (EC50), its efficacy in tissue respiration (IC50), and the paracrine and endocrine NO release. In this study, we review the NO literature, analyzing NO levels on various scales, identifying and analyzing the discrepancies in the reported data, and proposing hypotheses that can potentially reconcile these discrepancies. Resolving these issues is highly relevant to improving our understanding of vascular biology and to developing pharmaceutical agents that target NO pathways, such as vasodilating drugs.
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Affiliation(s)
- Kejing Chen
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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48
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Stewart JM, Medow MS, Minson CT, Taneja I. Cutaneous neuronal nitric oxide is specifically decreased in postural tachycardia syndrome. Am J Physiol Heart Circ Physiol 2007; 293:H2161-7. [PMID: 17660395 PMCID: PMC4511496 DOI: 10.1152/ajpheart.00600.2007] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Low flow postural tachycardia syndrome (POTS), is associated with reduced nitric oxide (NO) activity assumed to be of endothelial origin. We tested the hypothesis that cutaneous microvascular neuronal NO (nNO) is impaired, rather than endothelial NO (eNO), in POTS. We performed three sets of experiments on subjects aged 22.5 +/- 2 yr. We used laser-Doppler flowmetry response to sequentially increase acetylcholine (ACh) doses and the local cutaneous heating response of the calf as bioassays for NO. During local heating we showed that when the selective neuronal nNO synthase (nNOS) inhibitor N(omega)-nitro-L-arginine-2,4-L-diaminobutyric amide (N(omega), 10 mM) was delivered by intradermal microdialysis, cutaneous vascular conductance (CVC) decreased by an amount equivalent to the largest reduction produced by the nonselective NO synthase (NOS) inhibitor nitro-L-arginine (NLA, 10 mM). We demonstrated that the response to ACh was minimally attenuated by nNOS blockade using N(omega) but markedly attenuated by NLA, indicating that eNO largely comprises the receptor-mediated NO release by ACh. We further demonstrated that the ACh dose response was minimally reduced, whereas local heat-mediated NO-dependent responses were markedly reduced in POTS compared with control subjects. This is consistent with intact endothelial function and reduced NO of neuronal origin in POTS. The local heating response was highly attenuated in POTS [60 +/- 6 percent maximum CVC(%CVC(max))] compared with control (90 +/- 4 %CVC(max)), but the plateau response decreased to the same level with nNOS inhibition (50 +/- 3 %CVC(max) in POTS compared with 47 +/- 2 %CVC(max)), indicating reduced nNO bioavailability in POTS patients. The data suggest that nNO activity but not NO of endothelial NOS origin is reduced in low-flow POTS.
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Affiliation(s)
- Julian M Stewart
- The Center for Pediatric Hypotension, New York Medical College, Ste. 3050, 19 Bradhurst Ave., Hawthorne, NY 10532, USA.
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Ekshyyan VP, Hebert VY, Khandelwal A, Dugas TR. Resveratrol inhibits rat aortic vascular smooth muscle cell proliferation via estrogen receptor dependent nitric oxide production. J Cardiovasc Pharmacol 2007; 50:83-93. [PMID: 17666920 DOI: 10.1097/fjc.0b013e318059ae80] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Vascular smooth muscle cell (VSMC) proliferation is pivotal in the progression of hypertension, atherosclerosis, and restenosis. Resveratrol is a grape polyphenol that is implicated as an important contributor to red wine's vascular protective effects. Its antimitogenic action on VSMC is attributed to an array of pleiotropic effects, including modulation of the estrogen receptor (ER). To elucidate the mechanisms underlying resveratrol-mediated ER modulation and its inhibition of VSMC proliferation, we treated VSMC with resveratrol with or without the ER antagonist ICI 182,780 and measured cell proliferation and nitric oxide (NO) production. Resveratrol dose-dependently decreased VSMC DNA synthesis, with a half maximal inhibitory concentration (IC50) of 3.73+/-0.57 microM, and dramatically slowed cell growth, but did not induce VSMC apoptosis. Resveratrol-mediated decrease in proliferation was reversed by cotreatment with ICI 182,780, and resveratrol effectively competed with 17beta-estradiol for binding to the ER, exhibiting an IC50 of 8.92+/-0.14 microM. Resveratrol induced a sustained increase in ER-dependent NO production. Further, resveratrol-mediated decrease in VSMC proliferation was blunted by cotreatment with the general nitric oxide synthase (NOS) inhibitor N5-(1-Iminomethyl)-L-ornithine, dihydrochloride or with the inducible NOS (iNOS)-selective inhibitor S,S'-1,4-phenylene-bis (1,2-ethanediyl)bis-isothiourea, dihydrobromide, but not with the neuronal NOS-selective inhibitor 7-nitroindazole. Though resveratrol did not alter iNOS protein levels, it dose-dependently increased levels of iNOS activity, of the iNOS cofactor tetrahydrobiopterin (BH4), and of guanosine triphosphate cyclohydrolase I protein, the rate-limiting enzyme in BH4 biosynthesis. In addition, all of these effects were abolished by cotreatment with ICI 182,780. Thus, the antimitogenic effects of resveratrol on VSMC may be mediated by an ER-induced increase in iNOS activity.
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Affiliation(s)
- Viktoriya P Ekshyyan
- Department of Pharmacology, Toxicology & Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA 71130-3932, USA
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Chen K, Popel AS. Vascular and perivascular nitric oxide release and transport: biochemical pathways of neuronal nitric oxide synthase (NOS1) and endothelial nitric oxide synthase (NOS3). Free Radic Biol Med 2007; 42:811-22. [PMID: 17320763 PMCID: PMC1987713 DOI: 10.1016/j.freeradbiomed.2006.12.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Revised: 11/05/2006] [Accepted: 12/08/2006] [Indexed: 10/23/2022]
Abstract
Nitric oxide (NO) derived from nitric oxide synthase (NOS) is an important paracrine effector that maintains vascular tone. The release of NO mediated by NOS isozymes under various O(2) conditions critically determines the NO bioavailability in tissues. Because of experimental difficulties, there has been no direct information on how enzymatic NO production and distribution change around arterioles under various oxygen conditions. In this study, we used computational models based on the analysis of biochemical pathways of enzymatic NO synthesis and the availability of NOS isozymes to quantify the NO production by neuronal NOS (NOS1) and endothelial NOS (NOS3). We compared the catalytic activities of NOS1 and NOS3 and their sensitivities to the concentration of substrate O(2). Based on the NO release rates predicted from kinetic models, the geometric distribution of NO sources, and mass balance analysis, we predicted the NO concentration profiles around an arteriole under various O(2) conditions. The results indicated that NOS1-catalyzed NO production was significantly more sensitive to ambient O(2) concentration than that catalyzed by NOS3. Also, the high sensitivity of NOS1 catalytic activity to O(2) was associated with significantly reduced NO production and therefore NO concentrations, upon hypoxia. Moreover, the major source determining the distribution of NO was NOS1, which was abundantly expressed in the nerve fibers and mast cells close to arterioles, rather than NOS3, which was expressed in the endothelium. Finally, the perivascular NO concentration predicted by the models under conditions of normoxia was paradoxically at least an order of magnitude lower than a number of experimental measurements, suggesting a higher abundance of NOS1 or NOS3 and/or the existence of other enzymatic or nonenzymatic sources of NO in the microvasculature.
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Affiliation(s)
- Kejing Chen
- Department of Biomedical Engineering, 613 Traylor Building, 720 Rutland Avenue, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA.
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