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Longden TA, Lederer WJ. Electro-metabolic signaling. J Gen Physiol 2024; 156:e202313451. [PMID: 38197953 PMCID: PMC10783436 DOI: 10.1085/jgp.202313451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/27/2023] [Accepted: 12/14/2023] [Indexed: 01/11/2024] Open
Abstract
Precise matching of energy substrate delivery to local metabolic needs is essential for the health and function of all tissues. Here, we outline a mechanistic framework for understanding this critical process, which we refer to as electro-metabolic signaling (EMS). All tissues exhibit changes in metabolism over varying spatiotemporal scales and have widely varying energetic needs and reserves. We propose that across tissues, common signatures of elevated metabolism or increases in energy substrate usage that exceed key local thresholds rapidly engage mechanisms that generate hyperpolarizing electrical signals in capillaries that then relax contractile elements throughout the vasculature to quickly adjust blood flow to meet changing needs. The attendant increase in energy substrate delivery serves to meet local metabolic requirements and thus avoids a mismatch in supply and demand and prevents metabolic stress. We discuss in detail key examples of EMS that our laboratories have discovered in the brain and the heart, and we outline potential further EMS mechanisms operating in tissues such as skeletal muscle, pancreas, and kidney. We suggest that the energy imbalance evoked by EMS uncoupling may be central to cellular dysfunction from which the hallmarks of aging and metabolic diseases emerge and may lead to generalized organ failure states-such as diverse flavors of heart failure and dementia. Understanding and manipulating EMS may be key to preventing or reversing these dysfunctions.
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Affiliation(s)
- Thomas A. Longden
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Laboratory of Neurovascular Interactions, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - W. Jonathan Lederer
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Laboratory of Molecular Cardiology, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
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2
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King DR, Sedovy MW, Eaton X, Dunaway LS, Good ME, Isakson BE, Johnstone SR. Cell-To-Cell Communication in the Resistance Vasculature. Compr Physiol 2022; 12:3833-3867. [PMID: 35959755 DOI: 10.1002/cphy.c210040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The arterial vasculature can be divided into large conduit arteries, intermediate contractile arteries, resistance arteries, arterioles, and capillaries. Resistance arteries and arterioles primarily function to control systemic blood pressure. The resistance arteries are composed of a layer of endothelial cells oriented parallel to the direction of blood flow, which are separated by a matrix layer termed the internal elastic lamina from several layers of smooth muscle cells oriented perpendicular to the direction of blood flow. Cells within the vessel walls communicate in a homocellular and heterocellular fashion to govern luminal diameter, arterial resistance, and blood pressure. At rest, potassium currents govern the basal state of endothelial and smooth muscle cells. Multiple stimuli can elicit rises in intracellular calcium levels in either endothelial cells or smooth muscle cells, sourced from intracellular stores such as the endoplasmic reticulum or the extracellular space. In general, activation of endothelial cells results in the production of a vasodilatory signal, usually in the form of nitric oxide or endothelial-derived hyperpolarization. Conversely, activation of smooth muscle cells results in a vasoconstriction response through smooth muscle cell contraction. © 2022 American Physiological Society. Compr Physiol 12: 1-35, 2022.
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Affiliation(s)
- D Ryan King
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, Virginia Tech, Roanoke, Virginia, USA
| | - Meghan W Sedovy
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, Virginia Tech, Roanoke, Virginia, USA.,Translational Biology, Medicine, and Health Graduate Program, Virginia Tech, Blacksburg, Virginia, USA
| | - Xinyan Eaton
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, Virginia Tech, Roanoke, Virginia, USA
| | - Luke S Dunaway
- Robert M. Berne Cardiovascular Research Centre, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Miranda E Good
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, USA
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Centre, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Scott R Johnstone
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, Virginia Tech, Roanoke, Virginia, USA.,Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
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3
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A novel endothelium-independent effect of insulin on basal vascular tone in cafeteria diet-induced hypertensive rats. Eur J Pharmacol 2022; 925:174997. [PMID: 35513014 DOI: 10.1016/j.ejphar.2022.174997] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 04/26/2022] [Accepted: 04/28/2022] [Indexed: 01/04/2023]
Abstract
Insulin vasorelaxant effect in metabolic syndrome has been shown on precontracted vessels. However, the insulin effects on basal vascular tone and its interrelationship with nitric oxide (NO) and K-channels are unknown. To test the effect of insulin on the basal vascular tone in isolated aortic rings from the cafeteria diet-induced hypertensive rats and to determine the role of NO and K-channels on this insulin effect. Male Wistar rats were randomized into two groups: one group fed with a cafeteria diet (CafR) and another fed with a standard chow diet (control rats: CR). Then, in isolated aortic rings, the insulin effect on the basal tone and the role of K-channels were evaluated. Also, the endothelial function, NO levels, and resting membrane potential were measured. CafR increased blood pressure (138 ± 6.2 mmHg; n = 9 vs. CR: 109 ± 1.4 mmHg; n = 9; p < 0.001) and vascular basal tone. Insulin 400 mU/ml reduced basal tone in aortic rings (-284 ± 47 mg; n = 9). This effect was unaffected by endothelium removal or NG-nitro-l-arginine methyl ester (L-NAME) treatment. Likewise, CafR showed low NO levels and a hyperpolarized resting membrane potential. Insulin decreased the resting membrane potential and the KCa and Kv channels blockers abolished this effect. In CafR, endothelial dysfunction is accompanied by an increased basal tone. Insulin reduced it by Kv and KCa channels dependent mechanisms, using an endothelium-independent pathway. These results highlight a novel insulin effect on basal tone of aortic rings from animals with metabolic syndrome and endothelial dysfunction, pathophysiological conditions associated with human hypertension.
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Zhang H, Zhang X, Hong X, Tong X. Homogeneity or heterogeneity, the paradox of neurovascular pericytes in the brain. Glia 2021; 69:2474-2487. [PMID: 34152032 PMCID: PMC8453512 DOI: 10.1002/glia.24054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 05/25/2021] [Accepted: 06/11/2021] [Indexed: 11/11/2022]
Abstract
Pericytes are one of the main components of the neurovascular unit. They play a critical role in regulating blood flow, blood–brain barrier permeability, neuroinflammation, and neuronal activity. In the central nervous system (CNS), pericytes are classified into three subtypes, that is, ensheathing, mesh, and thin‐strand pericytes, based on their distinct morphologies and region‐specific distributions. However, whether these three types of pericytes exhibit heterogeneity or homogeneity with regard to membrane properties has been understudied to date. Here, we combined bulk RNA sequencing analysis with electrophysiological methods to demonstrate that the three subtypes of pericytes share similar electrical membrane properties in the CNS, suggesting a homogenous population of neurovascular pericytes in the brain. Furthermore, we identified an inwardly rectifying potassium channel subtype Kir4.1 functionally expressed in pericytes. Electrophysiological patch clamp recordings indicate that Kir4.1 channel currents in pericytes represent a small portion of the K+ macroscopic currents in physiological conditions. However, a significant augmentation of Kir4.1 currents in pericytes was induced when the extracellular K+ was elevated to pathological levels, suggesting pericytes Kir4.1 channels might play an important role as K+ sensors and contribute to K+ homeostasis in local neurovascular networks in pathology.
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Affiliation(s)
- Huimin Zhang
- Center for Brain Science of Shanghai Children's Medical Center, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiao Zhang
- Center for Brain Science of Shanghai Children's Medical Center, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaoqi Hong
- Center for Brain Science of Shanghai Children's Medical Center, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaoping Tong
- Center for Brain Science of Shanghai Children's Medical Center, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Guo P, Liu Y, Xu X, Ma G, Hou X, Fan Y, Zhang M. Coronary hypercontractility to acidosis owes to the greater activity of TMEM16A/ANO1 in the arterial smooth muscle cells. Biomed Pharmacother 2021; 139:111615. [PMID: 34243598 DOI: 10.1016/j.biopha.2021.111615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 04/05/2021] [Accepted: 04/12/2021] [Indexed: 10/21/2022] Open
Abstract
BACKGROUND Severe acidosis deteriorates cardiac injury. Rat coronary arteries (RCAs) are unusually hypercontractive to extracellular (o) acidosis (EA). TMEM16A-encoded anoctamin 1 (ANO1), a Ca2+-activated chloride channel (CaCC), plays an important role in regulating coronary arterial tension. PURPOSE We tested the possibility that the activation of CaCCs in the arterial smooth muscle cell (ASMC) contributes to EA-induced RCA constriction. METHODS ANO1 expression was detected with immunofluorescence staining and Western blot. TMEM16A mRNA was assessed with quantitative Real-Time PCR. Cl- currents and membrane potentials were quantified with a patch clamp. The vascular tension was recorded with a myograph. Intracellular (i) level of Cl- and Ca2+ was measured with fluorescent molecular probes. RESULTS ANO1 was expressed in all tested arterial myocytes, but was much more abundant in RCA ASMCs as compared with ASMCs isolated from rat cerebral basilar, intrarenal and mesenteric arteries. EA reduced [Cl-]i levels, augmented CaCC currents exclusively in RCA ASMCs and depolarized RCA ASMCs to a greater extent. Cl- deprivation, which depleted [Cl-]i by incubating the arteries or their ASMCs in Cl--free bath solution, decreased EA-induced [Cl-]i reduction, diminished EA-induced CaCC augmentation and time-dependently depressed EA-induced RCA constriction. Inhibitor studies showed that these EA-induced effects including RCA constriction, CaCC current augmentation, [Cl-]i reduction and/or [Ca2+]i elevation were depressed by various Cl- channel blockers, [Ca2+]i release inhibitors and L-type voltage-gated Ca2+ channel inhibitor nifedipine. ANO1 antibody attenuated all observed changes induced by EA in RCA ASMCs. CONCLUSION The greater activity of RCA ASMC CaCCs complicated with an enhanced Ca2+ mobilization from both [Ca2+]i release and [Ca2+]o influx plays a pivotal role in the distinctive hypercontractility of RCAs to acidosis. Translation of these findings to human beings may lead to a new conception in our understanding and treating cardiac complications in severe acidosis.
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Affiliation(s)
- Pengmei Guo
- Department of Pharmacology, Shanxi Medical University, Xinjiannanlu 56, Taiyuan 030001, Shanxi Province, China
| | - Yu Liu
- Department of Pharmacology, Shanxi Medical University, Xinjiannanlu 56, Taiyuan 030001, Shanxi Province, China
| | - Xiaojia Xu
- Department of Pharmacology, Shanxi Medical University, Xinjiannanlu 56, Taiyuan 030001, Shanxi Province, China
| | - Guijin Ma
- Department of Pharmacology, Shanxi Medical University, Xinjiannanlu 56, Taiyuan 030001, Shanxi Province, China
| | - Xiaomin Hou
- Department of Pharmacology, Shanxi Medical University, Xinjiannanlu 56, Taiyuan 030001, Shanxi Province, China
| | - Yanying Fan
- Department of Pharmacology, Shanxi Medical University, Xinjiannanlu 56, Taiyuan 030001, Shanxi Province, China.
| | - Mingsheng Zhang
- Department of Pharmacology, Shanxi Medical University, Xinjiannanlu 56, Taiyuan 030001, Shanxi Province, China.
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Garcia DCG, Longden TA. Ion channels in capillary endothelium. CURRENT TOPICS IN MEMBRANES 2020; 85:261-300. [PMID: 32402642 DOI: 10.1016/bs.ctm.2020.01.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Vascular beds are anatomically and functionally compartmentalized into arteries, capillaries, and veins. The bulk of the vasculature consists of the dense, anastomosing capillary network, composed of capillary endothelial cells (cECs) that are intimately associated with the parenchyma. Despite their abundance, the ion channel expression and function and Ca2+ signaling behaviors of capillaries have only recently begun to be explored in detail. Here, we discuss the established and emerging roles of ion channels and Ca2+ signaling in cECs. By mining a publicly available RNA-seq dataset, we outline the wide variety of ion channel genes that are expressed in these cells, which potentially imbue capillaries with a broad range of sensing and signal transduction capabilities. We also underscore subtle but critical differences between cEC and arteriolar EC ion channel expression that likely underlie key functional differences in ECs at these different levels of the vascular tree. We focus our discussion on the cerebral vasculature, but the findings and principles being elucidated in this area likely generalize to other vascular beds.
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Affiliation(s)
- Daniela C G Garcia
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Thomas A Longden
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States.
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7
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Hosford PS, Christie IN, Niranjan A, Aziz Q, Anderson N, Ang R, Lythgoe MF, Wells JA, Tinker A, Gourine AV. A critical role for the ATP-sensitive potassium channel subunit K IR6.1 in the control of cerebral blood flow. J Cereb Blood Flow Metab 2019; 39:2089-2095. [PMID: 29862863 PMCID: PMC6775590 DOI: 10.1177/0271678x18780602] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 04/20/2018] [Accepted: 05/01/2018] [Indexed: 12/19/2022]
Abstract
KIR6.1 (KCNJ8) is a subunit of ATP sensitive potassium channel (KATP) that plays an important role in the control of peripheral vascular tone and is highly expressed in brain contractile cells (vascular smooth muscle cells and pericytes). This study determined the effect of global deletion of the KIR6.1 subunit on cerebral blood flow, neurovascular coupling and cerebral oxygenation in mice. In KIR6.1 deficient mice resting cerebral blood flow and brain parenchymal partial pressure of oxygen (PO2) were found to be markedly lower compared to that in their wildtype littermates. However, cortical blood oxygen level dependent responses triggered by visual stimuli were not affected in conditions of KIR6.1 deficiency. These data suggest that KATP channels containing KIR6.1 subunit are critically important for the maintenance of normal cerebral perfusion and parenchymal PO2 but play no significant role in the mechanisms underlying functional changes in brain blood flow.
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Affiliation(s)
- Patrick S Hosford
- William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, London, UK
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - Isabel N Christie
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & Pharmacology, University College London, London, UK
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London, UK
| | - Arun Niranjan
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London, UK
| | - Qadeer Aziz
- William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, London, UK
| | - Naomi Anderson
- William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, London, UK
| | - Richard Ang
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - Mark F Lythgoe
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London, UK
| | - Jack A Wells
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London, UK
| | - Andrew Tinker
- William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, London, UK
| | - Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & Pharmacology, University College London, London, UK
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8
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Hoiland RL, Fisher JA, Ainslie PN. Regulation of the Cerebral Circulation by Arterial Carbon Dioxide. Compr Physiol 2019; 9:1101-1154. [DOI: 10.1002/cphy.c180021] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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9
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Increase in CO 2 levels by upregulating late sodium current is proarrhythmic in the heart. Heart Rhythm 2019; 16:1098-1106. [PMID: 30710739 DOI: 10.1016/j.hrthm.2019.01.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Indexed: 12/19/2022]
Abstract
BACKGROUND Increased CO2 levels in the general circulation and/or in the myocardium are common under pathologic conditions. OBJECTIVE The purpose of this study was to test the hypothesis that an increase in CO2 levels, and not just the subsequent extra- or intracellular acidosis, would augment late sodium current (INa,L) and contribute to arrhythmogenesis in hearts with reduced repolarization reserve. METHODS Monophasic action potential durations at 90% completion of repolarization (MAPD90) from isolated rabbit hearts, INa,L, and extra- (pHo) and intracellular pH (pHi) values from cardiomyocytes using the whole-cell patch-clamp techniques and 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein, acetoxymethyl ester (BCECF-AM), respectively, were measured. RESULTS Increasing CO2 levels from 5% to 10% and 20% and administration of 1 nM sea anemone toxin (ATX)-II increased INa,L and prolonged both epicardial and endocardial MAPD90 (n = 7 and 10, respectively) without causing arrhythmic activities. Compared to 5% CO2, 10% and 20% CO2 decreased pHo and pHi in hearts treated with 1 nM ATX-II, caused greater prolongation of MAPD90, and elicited ventricular tachycardias. Increasing CO2 levels from 5% to 10% and 20% with pHo maintained at 7.4 produced smaller changes in pHi (P <.05) but similar increases in INa,L, prolongation of MAPD90, and incidence of ventricular tachycardias (n = 8). Inhibition of INa,L reversed the increase in INa,L, suppressed MAPD90 prolongations, and ventricular tachycardias induced by 20% CO2. Increased phospho-calmodulin-dependent protein kinase II-δ (CaMKIIδ) and phospho-NaV1.5 protein levels in hearts treated with 20% CO2 was attenuated by eleclazine. CONCLUSION Increased CO2 levels enhance INa,L and are proarrhythmic factors in hearts with reduced repolarization reserve, possibly via mechanisms related to phosphorylation of CaMKIIδ and NaV1.5.
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Abstract
The human cerebral vasculature originates in the fourth week of gestation and continues to expand and diversify well into the first few years of postnatal life. A key feature of this growth is smooth muscle differentiation, whereby smooth muscle cells within cerebral arteries transform from migratory to proliferative to synthetic and finally to contractile phenotypes. These phenotypic transformations can be reversed by pathophysiological perturbations such as hypoxia, which causes loss of contractile capacity in immature cerebral arteries. In turn, loss of contractility affects all whole-brain cerebrovascular responses, including those involved in flow-metabolism coupling, vasodilatory responses to acute hypoxia and hypercapnia, cerebral autoregulation, and reactivity to activation of perivascular nerves. Future strategies to minimize cerebral injury following hypoxia-ischemic insults in the immature brain might benefit by targeting treatments to preserve and promote contractile differentiation in the fetal cerebrovasculature. This could potentially be achieved through inhibition of receptor tyrosine kinase-mediated growth factors, such as vascular endothelial growth factor and platelet-derived growth factor, which are mobilized by hypoxic and ischemic injury and which facilitate contractile dedifferentiation. Interruption of the effects of other vascular mitogens, such as endothelin and angiotensin-II, and even some miRNA species, also could be beneficial. Future experimental work that addresses these possibilities offers promise to improve current clinical management of neonates who have suffered and survived hypoxic, ischemic, asphyxic, or inflammatory cerebrovascular insults.
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Affiliation(s)
- William J Pearce
- From the Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA.
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11
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Tinker A, Aziz Q, Li Y, Specterman M. ATP‐Sensitive Potassium Channels and Their Physiological and Pathophysiological Roles. Compr Physiol 2018; 8:1463-1511. [DOI: 10.1002/cphy.c170048] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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12
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Charter ME, Lamb IR, Murrant CL. Arteriolar and capillary responses to CO2and H+in hamster skeletal muscle microvasculature: Implications for active hyperemia. Microcirculation 2018; 25:e12494. [DOI: 10.1111/micc.12494] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/21/2018] [Accepted: 07/18/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Mackenzie E. Charter
- Department of Human Health and Nutritional Sciences; University of Guelph; Guelph Ontario Canada
| | - Iain R. Lamb
- Department of Human Health and Nutritional Sciences; University of Guelph; Guelph Ontario Canada
| | - Coral L. Murrant
- Department of Human Health and Nutritional Sciences; University of Guelph; Guelph Ontario Canada
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13
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Gheibi S, Jeddi S, Kashfi K, Ghasemi A. Regulation of vascular tone homeostasis by NO and H 2S: Implications in hypertension. Biochem Pharmacol 2018; 149:42-59. [PMID: 29330066 PMCID: PMC5866223 DOI: 10.1016/j.bcp.2018.01.017] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 01/05/2018] [Indexed: 02/09/2023]
Abstract
Nitric oxide (NO) and hydrogen sulfide (H2S) are two gasotransmitters that are produced in the vasculature and contribute to the regulation of vascular tone. NO and H2S are synthesized in both vascular smooth muscle and endothelial cells; NO functions primarily through the sGC/cGMP pathway, and H2S mainly through activation of the ATP-dependent potassium channels; both leading to relaxation of vascular smooth muscle cells. A deficit in the NO/H2S homeostasis is involved in the pathogenesis of various cardiovascular diseases, especially hypertension. It is now becoming increasingly clear that there are important interactions between NO and H2S and that have a profound impact on vascular tone and this may provide insights into the new therapeutic interventions. The aim of this review is to provide a better understanding of individual and interactive roles of NO and H2S in vascular biology. Overall, available data indicate that both NO and H2S contribute to vascular (patho)physiology and in regulating blood pressure. In addition, boosting NO and H2S using various dietary sources or donors could be a hopeful therapeutic strategy in the management of hypertension.
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Affiliation(s)
- Sevda Gheibi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Neurophysiology Research Center and Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sajad Jeddi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, 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, NY, USA
| | - Asghar Ghasemi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Puchwein-Schwepcke AF, Schottmayer K, Mormanová Z, Dreyhaupt J, Genzel-Boroviczeny O, Thome UH. Permissive Hypercapnia Results in Decreased Functional Vessel Density in the Skin of Extremely Low Birth Weight Infants. Front Pediatr 2018; 6:52. [PMID: 29662873 PMCID: PMC5890181 DOI: 10.3389/fped.2018.00052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 02/23/2018] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Ventilator-induced lung injury with subsequent bronchopulmonary dysplasia remains an important issue in the care of extremely low-birth-weight infants. Permissive hypercapnia has been proposed to reduce lung injury. Hypercapnia changes cerebral perfusion, but its influence on the peripheral microcirculation is unknown. METHODS Data were collected from 12 infants, who were randomized to a permissive high PCO2 target group (HTG) or a control group (CG). Inclusion criteria were birth weight between 400 and 1,000 g, gestational age from 23 to 28 6/7 weeks, intubation during the first 24 h of life, and no malformations. The PCO2 target range was increased stepwise in both groups for weaning and was always 15 mmHg higher in the HTG than in the CG. Skin microvascular parameters were assessed non-invasively with sidestream dark field imaging on the inner side of the right arm every 24 h during the first week of life and on the 14th day of life. RESULTS Infants in the HTG had significantly higher max. PCO2 exposure, which was associated with a significantly and progressively reduced functional vessel density (FVD, p < 0.01). Moreover, there were significant differences in the diameter distribution over time, with HTG subjects having fewer small vessels but more large vessels. CONCLUSION High PCO2 levels significantly impaired peripheral microcirculation in preterm infants, as shown by a decreased FVD, presumably secondary to peripheral vasoconstriction. ISRCTN 56143743.
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Affiliation(s)
| | - Kristina Schottmayer
- Divsion of Neonatology, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Zuzana Mormanová
- Divsion of Neonatology, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Jens Dreyhaupt
- Institute for Epidemiology and Medical Biometry, University of Ulm, Ulm, Germany
| | - Orsolya Genzel-Boroviczeny
- Divsion of Neonatology, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Ulrich H Thome
- Divsion of Neonatology, University Hospital of Leipzig, Leipzig, Germany
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15
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Bridgett R, Klose P, Duffield R, Mydock S, Lauche R. Effects of Cupping Therapy in Amateur and Professional Athletes: Systematic Review of Randomized Controlled Trials. J Altern Complement Med 2017; 24:208-219. [PMID: 29185802 DOI: 10.1089/acm.2017.0191] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVE Despite the recent re-emergence of the process of cupping by athletes, supporting evidence for its efficacy and safety remains scarce. This systematic review aims to summarize the evidence of clinical trials on cupping for athletes. METHODS SCOPUS, Cochrane Library, PubMed, AMED, and CNKI databases were searched from their inception to December 10, 2016. Randomized controlled trials on cupping therapy with no restriction regarding the technique, or cointerventions, were included, if they measured the effects of cupping compared with any other intervention on health and performance outcomes in professionals, semi-professionals, and leisure athletes. Data extraction and risk of bias assessment using the Cochrane Risk of Bias Tool were conducted independently by two pairs of reviewers. RESULTS Eleven trials with n = 498 participants from China, the United States, Greece, Iran, and the United Arab Emirates were included, reporting effects on different populations, including soccer, football, and handball players, swimmers, gymnasts, and track and field athletes of both amateur and professional nature. Cupping was applied between 1 and 20 times, in daily or weekly intervals, alone or in combination with, for example, acupuncture. Outcomes varied greatly from symptom intensity, recovery measures, functional measures, serum markers, and experimental outcomes. Cupping was reported as beneficial for perceptions of pain and disability, increased range of motion, and reductions in creatine kinase when compared to mostly untreated control groups. The majority of trials had an unclear or high risk of bias. None of the studies reported safety. CONCLUSIONS No explicit recommendation for or against the use of cupping for athletes can be made. More studies are necessary for conclusive judgment on the efficacy and safety of cupping in athletes.
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Affiliation(s)
- Rhianna Bridgett
- 1 Endeavour College of Natural Health , Fortitude Valley, Australia
| | - Petra Klose
- 2 Department of Internal and Integrative Medicine, Kliniken Essen-Mitte, Faculty of Medicine, University of Duisburg-Essen , Essen, Germany
| | - Rob Duffield
- 3 Sport and Exercise Discipline Group, Faculty of Health, University of Technology Sydney , Sydney, NSW, Australia
| | - Suni Mydock
- 1 Endeavour College of Natural Health , Fortitude Valley, Australia
| | - Romy Lauche
- 4 Australian Research Centre in Complementary and Integrative Medicine (ARCCIM), Faculty of Health, University of Technology Sydney , Sydney, NSW, Australia
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Aleksandrowicz M, Dworakowska B, Dolowy K, Kozniewska E. Restoration of the response of the middle cerebral artery of the rat to acidosis in hyposmotic hyponatremia by the opener of large-conductance calcium sensitive potassium channels (BK Ca). J Cereb Blood Flow Metab 2017; 37:3219-3230. [PMID: 28058990 PMCID: PMC5584697 DOI: 10.1177/0271678x16685575] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Hyposmotic hyponatremia (the decrease of extracellular concentration of sodium ions from 145 to 121 mM and the decrease of hyposmolality from 300 to 250 mOsm/kg H2O) impairs response of the middle cerebral artery (MCA) to acetylcholine and NO donor (S-nitroso-N-acetyl-DL-penicillamine). Since acidosis activates a similar intracellular signaling pathway, the present study was designed to verify the hypothesis that the response of the MCA to acidosis is impaired during acute hyposmotic hyponatremia due to abnormal NO-related signal transduction in vascular smooth muscle cells. Studies performed on isolated, cannulated, and pressurized rat MCA revealed that hyposmotic hyponatremia impaired the response of the MCA to acidosis and this was associated with hyposmolality rather than with decreased sodium ion concentration. Response to acidosis was restored by the BKCa but not by the KATP channel activator. Patch-clamp electrophysiology performed on myocytes freshly isolated from MCAs, demonstrated that hyposmotic hyponatremia does not affect BKCa currents but decreases the voltage-dependency of the activation of the BKCa channels in the presence of a specific opener of these channels. Our study suggests that reduced sensitivity of BKCa channels in the MCA to agonists results in the lack of response of this artery to acidosis during acute hyposmotic hyponatremia.
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Affiliation(s)
- Marta Aleksandrowicz
- 1 Department of Neurosurgery, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Beata Dworakowska
- 2 Department of Biophysics, Warsaw University of Life Sciences, Warsaw, Poland
| | - Krzysztof Dolowy
- 2 Department of Biophysics, Warsaw University of Life Sciences, Warsaw, Poland
| | - Ewa Kozniewska
- 1 Department of Neurosurgery, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.,3 Department of Experimental and Clinical Physiology, Medical University of Warsaw, Warsaw, Poland
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17
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Laporte-Uribe JA. The role of dissolved carbon dioxide in both the decline in rumen pH and nutritional diseases in ruminants. Anim Feed Sci Technol 2016. [DOI: 10.1016/j.anifeedsci.2016.06.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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18
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Marowsky A, Haenel K, Bockamp E, Heck R, Rutishauser S, Mule N, Kindler D, Rudin M, Arand M. Genetic enhancement of microsomal epoxide hydrolase improves metabolic detoxification but impairs cerebral blood flow regulation. Arch Toxicol 2016; 90:3017-3027. [PMID: 26838043 PMCID: PMC5104800 DOI: 10.1007/s00204-016-1666-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 01/06/2016] [Indexed: 01/05/2023]
Abstract
Microsomal epoxide hydrolase (mEH) is a detoxifying enzyme for xenobiotic compounds. Enzymatic activity of mEH can be greatly increased by a point mutation, leading to an E404D amino acid exchange in its catalytic triad. Surprisingly, this variant is not found in any vertebrate species, despite the obvious advantage of accelerated detoxification. We hypothesized that this evolutionary avoidance is due to the fact that the mEH plays a dualistic role in detoxification and control of endogenous vascular signaling molecules. To test this, we generated mEH E404D mice and assessed them for detoxification capacity and vascular dynamics. In liver microsomes from these mice, turnover of the xenobiotic compound phenanthrene-9,10-oxide was four times faster compared to WT liver microsomes, confirming accelerated detoxification. mEH E404D animals also showed faster metabolization of a specific class of endogenous eicosanoids, arachidonic acid-derived epoxyeicosatrienoic acids (EETs) to dihydroxyeicosatrienoic acids (DHETs). Significantly higher DHETs/EETs ratios were found in mEH E404D liver, urine, plasma, brain and cerebral endothelial cells compared to WT controls, suggesting a broad impact of the mEH mutant on endogenous EETs metabolism. Because EETs are strong vasodilators in cerebral vasculature, hemodynamics were assessed in mEH E404D and WT cerebral cortex and hippocampus using cerebral blood volume (CBV)-based functional magnetic resonance imaging (fMRI). Basal CBV0 levels were similar between mEH E404D and control mice in both brain areas. But vascular reactivity and vasodilation in response to the vasodilatory drug acetazolamide were reduced in mEH E404D forebrain compared to WT controls by factor 3 and 2.6, respectively. These results demonstrate a critical role for mEH E404D in vasodynamics and suggest that deregulation of endogenous signaling pathways is the undesirable gain of function associated with the E404D variant.
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Affiliation(s)
- Anne Marowsky
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Karen Haenel
- Institute of Complex Systems (ICS-6), Research Center Julich, Wilhelm-Johnen-Straße, 52425, Julich, Germany
| | - Ernesto Bockamp
- Institute of Translational Immunology, University of Mainz, Obere Zahlbacherstrasse 63, 55131, Mainz, Germany
| | - Rosario Heck
- Institute of Translational Immunology, University of Mainz, Obere Zahlbacherstrasse 63, 55131, Mainz, Germany
| | - Sibylle Rutishauser
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Nandkishor Mule
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Diana Kindler
- Institute for Biomedical Engineering, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093, Zurich, Switzerland
| | - Markus Rudin
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.,Institute for Biomedical Engineering, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093, Zurich, Switzerland
| | - Michael Arand
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
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Sensitivity of KATP channels to cellular metabolic disorders and the underlying structural basis. Acta Pharmacol Sin 2016; 37:134-42. [PMID: 26725741 DOI: 10.1038/aps.2015.134] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 11/25/2015] [Indexed: 11/08/2022] Open
Abstract
AIM ATP-sensitive potassium (KATP) channels formed by a combination of SUR/Kir6.x subunits play a crucial role in protection against hypoxic or ischemic injuries resulting from cell metabolic disorders. In this study we investigated the effects of Na-azide, a metabolic inhibitor, on KATP channels expressed in Xenopus oocytes, and explored the structure basis for their sensitivity to cell metabolic disorders. METHODS Six subtypes of KATP channels (wild SUR1/Kir6.2, SUR2B/Kir6.2, SUR1/Kir6.1, SUR2B/Kir6.1, SUR2A/Kir6.2 and SUR2A/Kir6.1), as well as eleven subtypes of KATP channels with mutant subunits were expressed in Xenopus oocytes. KATP currents were recorded using a two-electrode voltage clamp recording technique. The drugs were applied through bath. RESULTS Except SUR2A/Kir6.1, five subtypes of KATP channels were activated by Na-azide (3 mmol/L) with an order of the responses: SUR1/Kir6.2>SUR2B/Kir6.2>SUR1/Kir6.1>SUR2B/Kir6.1>SUR2A/Kir6.2, and the opening rate (t1/2) was SUR1/Kir6.x>SUR2B/Kir6.x>SUR2A/Kir6.2. Furthermore, Kir6.2, rather than Kir6.1, had intrinsic sensitivity to Na-azide, and the residues involved in ATP-binding (R50 and K185) or pH-sensing (H175) were associated with the sensitivity of the Kir6.2 subunit to Na-azide. Moreover, the residues (K707 and K1348) within the Walker A (WA) motifs of two nucleotide-binding domains (NBDs) were essential for SUR2B/Kir6.x (especially SUR2B/Kir6.1) channel activation by Na-azide, suggesting a key role for Mg-adenine nucleotide binding and/or hydrolysis in the SUR2B subunit. CONCLUSION Among the six subtypes of KATP channels, SUR1/Kir6.2 is the most sensitive, whereas SUR2A/Kir6.1 is insensitive, to cell metabolic disorders. The Kir6.2 subunit, rather than the Kir6.1 subunit, has intrinsic sensitivity to cell metabolic disorders. The residues (K707 and K1348) within the WA motifs of SUR2B are important for the sensitivity of SUR2B/Kir6.x channels to cell metabolic disorders.
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20
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Chawla S, Ge Y, Lu H, Marshall O, Davitz MS, Fatterpekar G, Soher BJ, Gonen O. Whole-Brain N-Acetylaspartate Concentration Is Preserved during Mild Hypercapnia Challenge. AJNR Am J Neuroradiol 2015; 36:2055-61. [PMID: 26294651 PMCID: PMC4644678 DOI: 10.3174/ajnr.a4424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 04/01/2015] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Although NAA is often used as a marker of neuronal health and integrity in neurologic disorders, its normal response to physiologic challenge is not well-established and its changes are almost always attributed exclusively to brain pathology. The purpose of this study was to test the hypothesis that the neuronal cell marker NAA, often used to assess neuronal health and integrity in neurologic disorders, is not confounded by (possibly transient) physiologic changes. Therefore, its decline, when observed by using (1)H-MR spectroscopy, can almost always be attributed exclusively to brain pathology. MATERIALS AND METHODS Twelve healthy young male adults underwent a transient hypercapnia challenge (breathing 5% CO2 air mixture), a potent vasodilator known to cause a substantial increase in CBF and venous oxygenation. We evaluated their whole-brain NAA by using nonlocalizing proton MR spectroscopy, venous oxygenation with T2-relaxation under spin-tagging MR imaging, CBF with pseudocontinuous arterial spin-labeling, and the cerebral metabolic rate of oxygen, during normocapnia (breathing room air) and hypercapnia. RESULTS There was insignificant whole-brain NAA change (P = .88) from normocapnia to hypercapnia and back to normocapnia in this cohort, as opposed to highly significant increases: 28.0 ± 10.3% in venous oxygenation and 49.7 ± 16.6% in global CBF (P < 10(-4)); and a 6.4 ± 10.9% decrease in the global cerebral metabolic rate of oxygen (P = .04). CONCLUSIONS Stable whole-brain NAA during normocapnia and hypercapnia, despite significant global CBF and cerebral metabolic rate of oxygen changes, supports the hypothesis that global NAA changes are insensitive to transient physiology. Therefore, when observed, they most likely reflect underlying pathology resulting from neuronal cell integrity/viability changes, instead of a response to physiologic changes.
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Affiliation(s)
- S Chawla
- From the Department of Radiology (S.C., Y.G., O.M., M.S.D., G.F., O.G.), Center for Advanced Imaging Innovation and Research and Bernard and Irene Schwartz Center for Biomedical Imaging, New York University School of Medicine, New York, New York
| | - Y Ge
- From the Department of Radiology (S.C., Y.G., O.M., M.S.D., G.F., O.G.), Center for Advanced Imaging Innovation and Research and Bernard and Irene Schwartz Center for Biomedical Imaging, New York University School of Medicine, New York, New York
| | - H Lu
- The Russell H. Morgan Department of Radiology and Radiological Science (H.L.), Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - O Marshall
- From the Department of Radiology (S.C., Y.G., O.M., M.S.D., G.F., O.G.), Center for Advanced Imaging Innovation and Research and Bernard and Irene Schwartz Center for Biomedical Imaging, New York University School of Medicine, New York, New York
| | - M S Davitz
- From the Department of Radiology (S.C., Y.G., O.M., M.S.D., G.F., O.G.), Center for Advanced Imaging Innovation and Research and Bernard and Irene Schwartz Center for Biomedical Imaging, New York University School of Medicine, New York, New York
| | - G Fatterpekar
- From the Department of Radiology (S.C., Y.G., O.M., M.S.D., G.F., O.G.), Center for Advanced Imaging Innovation and Research and Bernard and Irene Schwartz Center for Biomedical Imaging, New York University School of Medicine, New York, New York
| | - B J Soher
- Department of Radiology (B.J.S.), Center for Advanced MR Development, Duke University Medical Center, Durham, North Carolina
| | - O Gonen
- From the Department of Radiology (S.C., Y.G., O.M., M.S.D., G.F., O.G.), Center for Advanced Imaging Innovation and Research and Bernard and Irene Schwartz Center for Biomedical Imaging, New York University School of Medicine, New York, New York
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21
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Beck C, Barthel F, Hahn AM, Vollmer C, Herminghaus A, Schäfer S, Bauer I, Picker O. The beneficial effects of acute hypercapnia on microcirculatory oxygenation in an animal model of sepsis are independent of K(+)ATP channels. Microvasc Res 2015; 99:78-85. [PMID: 25758765 DOI: 10.1016/j.mvr.2015.02.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 02/13/2015] [Accepted: 02/27/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Acute hypercapnia maintains the microcirculatory oxygenation of the splanchnic region during sepsis. The first aim of this study was to characterize the role of K(+)ATP channels on the microcirculatory flow and oxygenation during acute moderate hypercapnia. The second aim was to investigate whether a short period of hypercapnia induces detrimental effects in an otherwise undamaged rodent lung. METHODS Experiments were performed on 60 male Wistar rats. A moderate polymicrobial sepsis was induced by colon ascendens stent peritonitis (CASP) surgery. 24h after induction of sepsis volume-controlled and pressure-limited ventilation was established for 120 min, with either normocapnic (pCO2 35-45 mmHg) or moderate hypercapnic ventilation targets (pCO2 65-75 mmHg) and with or without non-selective K(+)ATP channel blockade with glibenclamide. Microcirculatory blood flow of the colonic wall as well as oxygen delivery and consumption were assessed with tissue laser Doppler and reflectance spectrophotometry. Hemodynamic variables were recorded and plasma cytokine levels and myeloperoxidase levels of the lungs were analyzed. RESULTS In septic animals microcirculatory oxygenation deteriorated progressively with normocapnia (-11.7 ± 11.8%) but was maintained (-2.9 ± 5.6%) with hypercapnia. This effect was associated with an increased microcirculatory oxygen consumption in septic animals with normocapnia (+25.7 ± 37.1%) that was decreased in the hypercapnia groups (-7.2 ± 28.1%). The effect of hypercapnia in septic animals was not altered by additional K(+)ATP channel blockade (-5.7 ± 32.7%). Hypercapnia neither induced an inflammatory response in lungs nor altered the systemic cytokine response. CONCLUSIONS The observed beneficial effect of hypercapnia on microvascular oxygenation of the colon in sepsis does not seem to be mediated via K(+)ATP channels.
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Affiliation(s)
- Christopher Beck
- Department of Anaesthesiology, University Hospital Duesseldorf, Germany
| | - Franziska Barthel
- Department of Anaesthesiology, University Hospital Duesseldorf, Germany
| | - Anna-Maria Hahn
- Department of Anaesthesiology, University Hospital Duesseldorf, Germany
| | - Christian Vollmer
- Department of Anaesthesiology, University Hospital Duesseldorf, Germany
| | - Anna Herminghaus
- Department of Anaesthesiology, University Hospital Duesseldorf, Germany
| | - Sabrina Schäfer
- Department of Anaesthesiology, University Hospital Duesseldorf, Germany
| | - Inge Bauer
- Department of Anaesthesiology, University Hospital Duesseldorf, Germany
| | - Olaf Picker
- Department of Anaesthesiology, University Hospital Duesseldorf, Germany.
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22
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Bawaskar HS, Bawaskar PH, Bawaskar PH. Refractory hyperkalemia related to heparin abuse. Indian J Crit Care Med 2014; 18:765-6. [PMID: 25425851 PMCID: PMC4238101 DOI: 10.4103/0972-5229.144032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Affiliation(s)
- Himmatrao S Bawaskar
- Department of Clinical Medicine, Bawaskar Hospital and Research Center, Mahad Raigad, Maharashtra, India
| | - Parag H Bawaskar
- Department of Clinical Medicine, Bawaskar Hospital and Research Center, Mahad Raigad, Maharashtra, India
| | - Pramodini H Bawaskar
- Department of Clinical Medicine, Bawaskar Hospital and Research Center, Mahad Raigad, Maharashtra, India
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Nnorom CC, Davis C, Fedinec AL, Howell K, Jaggar JH, Parfenova H, Pourcyrous M, Leffler CW. Contributions of KATP and KCa channels to cerebral arteriolar dilation to hypercapnia in neonatal brain. Physiol Rep 2014; 2:2/8/e12127. [PMID: 25168876 PMCID: PMC4246596 DOI: 10.14814/phy2.12127] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Mechanisms by which Pco2 controls cerebral vascular tone remain uncertain. We hypothesize that potassium channel activation contributes to the neonatal cerebrovascular dilation in response to increases in Paco2. To test this hypothesis, experiments were performed on newborn pigs with surgically implanted, closed cranial windows. Hypercapnia was induced by ventilation with elevated Pco2 gas in the absence and presence of the KATP channel inhibitor, glibenclamide and/or the KCa channel inhibitor, paxillin. Dilations to pinacidil, a selective KATP channel activator, without and with glibenclamide, were used to evaluate the efficacy of KATP channel inhibition. Dilations to NS1619, a selective KCa channel activator, without and with paxillin, were used to evaluate the efficacy of KCa channel inhibition. Cerebrovascular responses to the KATP and KCa channel activators, pinacidil and NS1619, respectively, cAMP‐dependent dilator, isoproterenol, and cGMP‐dependent dilator, sodium nitroprusside (SNP), were used to evaluate the selectivity of glibenclamide and paxillin. Glibenclamide blocked dilation to pinacidil, but did not inhibit dilations to NS1619, isoproterenol, or SNP. Glibenclamide prior to hypercapnia decreased mean pial arteriole dilation ~60%. Glibenclamide treatment during hypercapnia constricted arterioles ~35%. The level of hypercapnia, Paco2 between 50 and 75 mmHg, did not appear to be involved in efficacy of glibenclamide in blocking dilation to Paco2. Similarly to glibenclamide and KATP channel inhibition, paxillin blocked dilation to the KCa channel agonist, NS1619, and attenuated, but did not block, arteriolar dilation to hypercapnia. Treatment with both glibenclamide and paxillin abolished dilation to hypercapnia. Therefore, either glibenclamide or paxillin that block dilation to their channel agonists, pinacidil or NS1619, respectively, only partially inhibit dilation to hypercapnia. Block of both KATP and KCa channels completely prevent dilation hypercapnia. These data suggest hypercapnia activates both KATP and KCa channels leading to cerebral arteriolar dilation in newborn pigs. Mechanisms by which Pco2 controls vascular tone remain uncertain. We hypothesize KATP and KCa channel activation contributes to the neonatal cerebrovascular dilation in response to increases in Paco2. Presented data support this hypothesis.
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Affiliation(s)
- Chukwuma C Nnorom
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Corinne Davis
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Alexander L Fedinec
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Khadesia Howell
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Jonathan H Jaggar
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Helena Parfenova
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Massroor Pourcyrous
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Charles W Leffler
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
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Abstract
The field of mitochondrial ion channels has recently seen substantial progress, including the molecular identification of some of the channels. An integrative approach using genetics, electrophysiology, pharmacology, and cell biology to clarify the roles of these channels has thus become possible. It is by now clear that many of these channels are important for energy supply by the mitochondria and have a major impact on the fate of the entire cell as well. The purpose of this review is to provide an up-to-date overview of the electrophysiological properties, molecular identity, and pathophysiological functions of the mitochondrial ion channels studied so far and to highlight possible therapeutic perspectives based on current information.
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25
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Xia H, Zhang D, Yang S, Wang Y, Xu L, Wu J, Ren J, Yao W, Fan L, Zhang C, Tian Y, Pan HL, Wang X. Role of ATP-sensitive potassium channels in modulating nociception in rat model of bone cancer pain. Brain Res 2014; 1554:29-35. [DOI: 10.1016/j.brainres.2014.01.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 01/14/2014] [Accepted: 01/18/2014] [Indexed: 12/22/2022]
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Emerich M, Braeunig M, Clement HW, Lüdtke R, Huber R. Mode of action of cupping--local metabolism and pain thresholds in neck pain patients and healthy subjects. Complement Ther Med 2014; 22:148-58. [PMID: 24559830 DOI: 10.1016/j.ctim.2013.12.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 12/06/2013] [Accepted: 12/28/2013] [Indexed: 10/25/2022] Open
Abstract
OBJECTIVES Cupping worldwide has been part of traditional medicine systems and is in the western world used as CAM therapy mainly for treating pain syndromes. The mode of action is up to now unclear. In order to investigate its mechanism we measured in parallel metabolic changes in the tissue under the cupping glass and pressure pain thresholds. DESIGN AND INTERVENTIONS In 12 volunteers (6 healthy subjects and 6 patients with chronic neck pain) a microdialysis system was implanted subcutaneously on both sides (left and right) above the trapezius muscle. After baseline measures cupping was performed at one randomly selected side (left or right), the other side served as control. Every 20 min during baseline measures and for 280 min after cupping, microdialysis probes for detection of lactate, pyruvate, glucose and glycerin were taken. In addition, pain thresholds were measured before and after cupping with algometry. RESULTS Cupping resulted in a strong increase of lactate (beginning 160 min after cupping until the end of the measurements) and the lactate/pyruvate ratio, indicating an anaerobe metabolism in the surrounding tissue. Baseline pain thresholds were non-significantly lower in neck pain patients compared to healthy controls and slightly increased immediately after cupping (p<0.05 compared to baseline close to the area of cupping in healthy subjects and on the foot in neck pain patients). After 280 min no more significant changes of pain thresholds were detected. CONCLUSIONS Cupping induces >280 min lasting anaerobe metabolism in the subcutaneous tissue and increases immediate pressure pain thresholds in some areas.
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Affiliation(s)
- M Emerich
- Center for Complementary Medicine, Department of Environmental Health Sciences, University Medical Center, 79106 Freiburg, Germany
| | - M Braeunig
- Department Psychosomatic Medicine, University Medical Center, 79106 Freiburg, Germany
| | - H W Clement
- Department Child and Youth Psychiatry, University Medical Center, 79106 Freiburg, Germany
| | - R Lüdtke
- Karl und Veronica Carstens-Foundation, 45276 Essen, Germany
| | - R Huber
- Center for Complementary Medicine, Department of Environmental Health Sciences, University Medical Center, 79106 Freiburg, Germany.
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Stübs CC, Picker O, Schulz J, Obermiller K, Barthel F, Hahn AM, Bauer I, Beck C. Acute, short-term hypercapnia improves microvascular oxygenation of the colon in an animal model of sepsis. Microvasc Res 2013; 90:180-6. [DOI: 10.1016/j.mvr.2013.07.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 06/25/2013] [Accepted: 07/22/2013] [Indexed: 12/13/2022]
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Glodzik L, Randall C, Rusinek H, de Leon MJ. Cerebrovascular reactivity to carbon dioxide in Alzheimer's disease. J Alzheimers Dis 2013; 35:427-40. [PMID: 23478306 DOI: 10.3233/jad-122011] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
There is growing evidence that cerebrovascular reactivity to carbon dioxide (CVRCO2) is impaired in Alzheimer's disease (AD). Preclinical and animal studies suggest chronic hypercontractility in brain vessels in AD. We review (a) preclinical studies of mechanisms for impaired CVRCO2 in AD; (b) clinical studies of cerebrovascular function in subjects with AD dementia, mild cognitive impairment (MCI), and normal cognition. Although results of clinical studies are inconclusive, an increasing number of reports reveal an impairment of vascular reactivity to carbon dioxide in subjects with AD, and possibly also in MCI. Thus, CVRCO2 may be an attractive means to detect an early vascular dysfunction in subjects at risk.
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Affiliation(s)
- Lidia Glodzik
- Center for Brain Health, Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA.
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Regulation of inflammation by extracellular acidification and proton-sensing GPCRs. Cell Signal 2013; 25:2263-71. [PMID: 23917207 DOI: 10.1016/j.cellsig.2013.07.022] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Accepted: 07/26/2013] [Indexed: 12/14/2022]
Abstract
Under ischemic and inflammatory circumstances, such as allergic airway asthma, rheumatoid arthritis, atherosclerosis, and tumors, extracellular acidification occurs due to the stimulation of anaerobic glycolysis. An acidic microenvironment has been shown to modulate pro-inflammatory or anti-inflammatory responses, including cyclooxygenase-2 (COX-2) expression, prostaglandin synthesis, and cytokine expression, in a variety of cell types, and thereby to exacerbate or ameliorate inflammation. However, molecular mechanisms underlying extracellular acidic pH-induced actions have not been fully understood. Recent studies have shown that ovarian cancer G protein-coupled receptor 1 (OGR1)-family G protein-coupled receptors (GPCRs) can sense extracellular pH or protons, which in turn stimulates intracellular signaling pathways and subsequent diverse cellular responses. In the present review, I discuss extracellular acidic pH-induced inflammatory responses and related responses in inflammatory cells, such as macrophages and neutrophils, and non-inflammatory cells, such as smooth muscle cells and endothelial cells, focusing especially on proton-sensing GPCRs.
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Martelli A, Manfroni G, Sabbatini P, Barreca ML, Testai L, Novelli M, Sabatini S, Massari S, Tabarrini O, Masiello P, Calderone V, Cecchetti V. 1,4-Benzothiazine ATP-Sensitive Potassium Channel Openers: Modifications at the C-2 and C-6 Positions. J Med Chem 2013; 56:4718-28. [DOI: 10.1021/jm400435a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alma Martelli
- Dipartimento di Farmacia, Università degli Studi di Pisa, Via Bonanno
6, 56126 Pisa, Italy
| | - Giuseppe Manfroni
- Dipartimento di Chimica e Tecnologia
del Farmaco, Università degli Studi di Perugia, Via del Liceo, 1, 06123 Perugia, Italy
| | - Paola Sabbatini
- Dipartimento di Chimica e Tecnologia
del Farmaco, Università degli Studi di Perugia, Via del Liceo, 1, 06123 Perugia, Italy
| | - Maria Letizia Barreca
- Dipartimento di Chimica e Tecnologia
del Farmaco, Università degli Studi di Perugia, Via del Liceo, 1, 06123 Perugia, Italy
| | - Lara Testai
- Dipartimento di Farmacia, Università degli Studi di Pisa, Via Bonanno
6, 56126 Pisa, Italy
| | - Michela Novelli
- Dipartimento
di Ricerca Traslazionale
e delle Nuove Tecnologie in Medicina e Chirurgia, Università degli Studi di Pisa, Via Roma, 55, 56126 Pisa, Italy
| | - Stefano Sabatini
- Dipartimento di Chimica e Tecnologia
del Farmaco, Università degli Studi di Perugia, Via del Liceo, 1, 06123 Perugia, Italy
| | - Serena Massari
- Dipartimento di Chimica e Tecnologia
del Farmaco, Università degli Studi di Perugia, Via del Liceo, 1, 06123 Perugia, Italy
| | - Oriana Tabarrini
- Dipartimento di Chimica e Tecnologia
del Farmaco, Università degli Studi di Perugia, Via del Liceo, 1, 06123 Perugia, Italy
| | - Pellegrino Masiello
- Dipartimento
di Ricerca Traslazionale
e delle Nuove Tecnologie in Medicina e Chirurgia, Università degli Studi di Pisa, Via Roma, 55, 56126 Pisa, Italy
| | - Vincenzo Calderone
- Dipartimento di Farmacia, Università degli Studi di Pisa, Via Bonanno
6, 56126 Pisa, Italy
| | - Violetta Cecchetti
- Dipartimento di Chimica e Tecnologia
del Farmaco, Università degli Studi di Perugia, Via del Liceo, 1, 06123 Perugia, Italy
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Wang Y, Yu L, Cui N, Jin X, Zhu D, Jiang C. Differential sensitivities of the vascular K(ATP) channel to various PPAR activators. Biochem Pharmacol 2013; 85:1495-503. [PMID: 23500542 DOI: 10.1016/j.bcp.2013.02.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 02/26/2013] [Accepted: 02/27/2013] [Indexed: 12/11/2022]
Abstract
Several agonists of the peroxisome proliferator-activated receptors (PPARs) are currently used for the treatment of metabolic disorders including diabetes. We have recently shown that one of them, Rosiglitazone, inhibits the vascular ATP-sensitive K⁺ (K(ATP)) channel and compromises the coronary vasodilation by the β-adrenoceptor agonist. Here, we show evidence for the channel inhibition by various PPAR agonists, information that may be useful for finding new therapeutical agents with less cardiovascular side-effects and more selective K(ATP) channel blockers targeting at the K(ir)6.1 subunit. Structural comparison of these PPAR agonists may shed insight into the critical chemical groups for the channel inhibition. K(ir)6.1/SUR2B channel was expressed in HEK293 cells and studied in whole-cell voltage clamp. The K(ir)6.1/SUR2B channel was strongly inhibited by several PPAR(γ) agonists with potencies similar to, or higher than, that of Rosiglitazone, while other PPAR(γ) agonists barely inhibited the channel. The K(ir)6.1/SUR2B channel was also inhibited by PPAR(α) and PPAR(β/δ) agonists with intermediate potencies. The structure necessary for the channel inhibition appears to include the thiazole linked to an aromatic or furan ring. Additions of side groups such as small aliphatic chain increased the potency for channel inhibition, while additions of aromatic rings reduced it. These results indicate that the PPAR(γ) agonists with weak K(ATP) channel inhibition may be potential candidates as therapeutical agents, and those with strong channel inhibition may be used as selective K(ATP) channel blockers. The structural information of the PPAR agonists may be useful for the development of new therapeutical modalities with less cardiovascular side-effects.
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Affiliation(s)
- Yingji Wang
- Department of Biology, Georgia State University, Atlanta, GA 30302-4010, USA
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32
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Liu YH, Lu M, Hu LF, Wong PTH, Webb GD, Bian JS. Hydrogen sulfide in the mammalian cardiovascular system. Antioxid Redox Signal 2012; 17:141-85. [PMID: 22304473 DOI: 10.1089/ars.2011.4005] [Citation(s) in RCA: 197] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
For more than a century, hydrogen sulfide (H(2)S) has been regarded as a toxic gas. This review surveys the growing recognition of the role of H(2)S as an endogenous signaling molecule in mammals, with emphasis on its physiological and pathological pathways in the cardiovascular system. In biological fluids, H(2)S gas is a weak acid that exists as about 15% H(2)S, 85% HS(-), and a trace of S(2-). Here, we use "H(2)S" to refer to this mixture. H(2)S has been found to influence heart contractile functions and may serve as a cardioprotectant for treating ischemic heart diseases and heart failure. Alterations of the endogenous H(2)S level have been found in animal models with various pathological conditions such as myocardial ischemia, spontaneous hypertension, and hypoxic pulmonary hypertension. In the vascular system, H(2)S exerts biphasic regulation of a vascular tone with varying effects based on its concentration and in the presence of nitric oxide. Over the past decade, several H(2)S-releasing compounds (NaHS, Na(2)S, GYY4137, etc.) have been utilized to test the effect of exogenous H(2)S under different physiological and pathological situations in vivo and in vitro. H(2)S has been found to promote angiogenesis and to protect against atherosclerosis and hypertension, while excess H(2)S may promote inflammation in septic or hemorrhagic shock. H(2)S-releasing compounds and inhibitors of H(2)S synthesis hold promise in alleviating specific disease conditions. This comprehensive review covers in detail the effects of H(2)S on the cardiovascular system, especially in disease situations, and also the various underlying mechanisms.
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Affiliation(s)
- Yi-Hong Liu
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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Abstract
Hydrogen sulfide (H2S) is an endogenous gasotransmitter produced in mammalian cells. It is responsible for physiological functions in many organs and systems, with attention focused mainly on the cardiovascular and nervous systems. In the vascular system, H2S produces biphasic effects in regulation of vascular tone. At lower concentrations, it induces vasoconstriction predominantly via decreasing cyclic adenosine monophosphate in smooth muscle cell and inhibiting the production and bioavailability of nitric oxide. At higher concentrations, it produces vasorelaxation mainly through opening of KATP channels and induction of intracellular acidification. Scavenging reactive oxygen species and elevation of cyclic guanosine monophosphate are also implicated in the vasorelaxant response. This review presents an overview of the current knowledge of H2S in the vascular system, with special emphasis and discussion on the involvement of various signaling pathways and ion channels based on current understanding and reported literature till date.
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Kinoshita H, Matsuda N, Iranami H, Ogawa K, Hatakeyama N, Azma T, Kawahito S, Yamazaki M. Isoflurane pretreatment preserves adenosine triphosphate-sensitive K(+) channel function in the human artery exposed to oxidative stress caused by high glucose levels. Anesth Analg 2012; 115:54-61. [PMID: 22467893 DOI: 10.1213/ane.0b013e318254270d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Adenosine triphosphate (ATP)-sensitive K(+) channels contribute to significant regulatory mechanisms related to organ blood flow in both physiological and pathological conditions. High glucose impairs arterial ATP-sensitive K(+) channel activity via superoxide production. However, the effects of anesthetics on this pathological process have not been evaluated in humans. In the present study, we investigated whether pretreatment with the volatile anesthetic isoflurane preserves ATP-sensitive K(+) channel activity in the human artery exposed to oxidative stress caused by high glucose. METHODS All experiments were performed using human omental arteries without endothelium in the presence of d-glucose (5.5 mmol/L). Some arteries were treated with isoflurane (1.15% or 2.3%) in combination with d- or l-glucose (20 mmol/L) for 60 minutes, and then only isoflurane was discontinued. Relaxation and hyperpolarization of arterial segments in response to an ATP-sensitive K(+) channel opener levcromakalim were evaluated using the isometric force recording or electrophysiological study, respectively. Superoxide production was determined by dihydroethidium fluorescence. Immunohistochemical analysis for a subunit of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase p47phox was performed. Data were evaluated using repeated-measures analysis of variance or a factorial analysis of variance as appropriate, followed by Scheffé test. RESULTS The ATP-sensitive K(+) channel antagonist glibenclamide (10(-6) mol/L) abolished relaxation induced by cumulative addition of levcromakalim (10(-8) to 10(-5) mol/L) in arteries treated with l-glucose (20 mmol/L). Incubation with d-glucose (20 mmol/L) impaired the vasorelaxation induced by levcromakalim. The selective NADPH oxidase NOX2 inhibitor gp91ds-tat (10(-6) mol/L) and pretreatment with isoflurane (1.15% and 2.3%) restored relaxation in response to levcromakalim in arteries treated with d-glucose (20 mmol/L). Isoflurane (2.3%), gp91ds-tat (10(-6) mol/L), and their combination similarly restored hyperpolarization in response to levcromakalim (3 × 10(-6) mol/L) in arteries treated with d-glucose (20 mmol/L). Along with these results, isoflurane (2.3%) reduced superoxide production and the intracellular mobilization of the cytosolic NOX2 subunit p47phox toward smooth muscle cell membrane in arteries treated with d-glucose (20 mmol/L). CONCLUSIONS We have demonstrated for the first time a beneficial effect from the pretreatment with isoflurane on the isolated human artery. Pretreatment with isoflurane preserves ATP-sensitive K(+) channel activity in the human omental artery exposed to oxidative stress induced by high glucose, whereas the effect seems to be mediated by NADPH oxidase inhibition. Volatile anesthetics may protect human visceral arteries from malfunction caused by oxidative stress.
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Affiliation(s)
- Hiroyuki Kinoshita
- Department of Anesthesiology, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-0012, Japan.
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Yu L, Jin X, Yang Y, Cui N, Jiang C. Rosiglitazone inhibits vascular KATP channels and coronary vasodilation produced by isoprenaline. Br J Pharmacol 2012; 164:2064-72. [PMID: 21671900 DOI: 10.1111/j.1476-5381.2011.01539.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE Rosiglitazone is an anti-diabetic drug improving insulin sensitivity and glucose uptake in skeletal muscle and adipose tissues. However, several recent clinical trials suggest that rosiglitazone can increase the risk of cardiovascular ischaemia, although other studies failed to show such risks. Therefore, the effects of rosiglitazone on the coronary circulation and any potential vascular targets need to be elucidated. Here, we show that the vascular isoform of the ATP-sensitive K(+) (K(ATP) ) channel is inhibited by rosiglitazone, impairing physiological regulation of the coronary circulation. EXPERIMENTAL APPROACH The K(IR) 6.1/SUR2B channel was expressed in HEK293 cells and studied in whole-cell and inside-out patch configurations. The Langendorff heart preparation was used to evaluate rosiglitazone in the coronary circulation of wild-type (WT) and K(IR) 6.1-null (Kcnj8(-/-) ) mice. KEY RESULTS K(IR) 6.1/SUR2B channels in HEK cells were inhibited by rosiglitazone in a membrane-delimited manner. This effect was markedly enhanced by sub-micromolar concentrations of glibenclamide and the IC(50) for rosiglitazone fell to 2µM, a therapeutically achievable concentration. In the Langendorff heart preparation rosiglitazone inhibited, concentration-dependently, the coronary vasodilation induced by isoprenaline, without affecting basal coronary tone. Effects of rosiglitazone on coronary perfusion were attenuated by more than 50% in the Kcnj8(-/-) mice, supporting the involvement of K(ATP) channels in this effect of rosiglitazone on the coronary circulation. CONCLUSIONS AND IMPLICATIONS These results indicate that the vascular K(ATP) channel is one of the targets of rosiglitazone action, through which this drug may compromise coronary responses to circulating vasodilators and perhaps also to metabolic stress.
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Affiliation(s)
- Lei Yu
- Department of Biology, Georgia State University, Atlanta, GA 30302, USA
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Liu Y, Zhang J, Yu L, Cao F, Rao J, Li J, Jiang C, Falck JR, Jacobs ER, Zhu D. A soluble epoxide hydrolase inhibitor--8-HUDE increases pulmonary vasoconstriction through inhibition of K(ATP) channels. Pulm Pharmacol Ther 2011; 25:69-76. [PMID: 22155000 DOI: 10.1016/j.pupt.2011.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Revised: 11/07/2011] [Accepted: 11/26/2011] [Indexed: 11/17/2022]
Abstract
Epoxyeicosatrienoic acids (EETs), cytochrome P450-derived metabolites of arachidonic acid, are endogenously produced epoxides that act as substrates for the soluble epoxide hydrolase (sEH). Recent studies indicate that EETs increase the tension of rat pulmonary arteries (PAs), and inhibition of sEH augments hypoxic pulmonary vasoconstriction. However, the mechanisms underlying the proconstrictive effects of sEH inhibitors in pulmonary artery smooth muscle cells (PASMCs) are unclear. In the present study, we used a sEH inhibitor, 12-(3-hexylureido) dodec-8-enoic acid (8-HUDE), to examine the ionic mechanisms underlying the constriction of PAs. 8-HUDE increased the tension of rat PAs to 145% baseline in a manner which was effectively eliminated by 10 μmol/L glibenclamide, an inhibitor of ATP-sensitive K(+) (K(ATP)) channels. Whole cell currents of HEK cells transfected with Kir6.1 or SUR2B were activated by K(ATP) channel opener pinacidil, inhibited by K(ATP) channel inhibitor glibenclamide or inhibited by 8-HUDE in a concentration-dependent manner with an IC50 value of 40 uM. In addition, 8-HUDE inhibited the expression of Kir6.1 and SUR2B at both mRNA and protein level in rat PASMCs. These observations suggest that 8-HUDE exerts acute effects on K(ATP) channel activity as well as subacute effects through decreased channel expression, and these effects are, at least in part, via the Kir6.1/SUR2B channel.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/pharmacology
- ATP-Binding Cassette Transporters/antagonists & inhibitors
- ATP-Binding Cassette Transporters/biosynthesis
- Animals
- Blotting, Western
- Cells, Cultured
- Enzyme Inhibitors/pharmacology
- Epoxide Hydrolases/antagonists & inhibitors
- Fatty Acids, Monounsaturated/pharmacology
- Female
- HEK293 Cells
- Humans
- KATP Channels/antagonists & inhibitors
- KATP Channels/biosynthesis
- Male
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/drug effects
- Myocytes, Smooth Muscle/drug effects
- Patch-Clamp Techniques
- Potassium Channel Blockers/pharmacology
- Potassium Channels, Inwardly Rectifying/antagonists & inhibitors
- Potassium Channels, Inwardly Rectifying/biosynthesis
- Pulmonary Artery/drug effects
- Pulmonary Circulation/drug effects
- Rats
- Rats, Wistar
- Real-Time Polymerase Chain Reaction
- Receptors, Drug/antagonists & inhibitors
- Receptors, Drug/biosynthesis
- Sulfonylurea Receptors
- Vasoconstriction/drug effects
- Vasodilator Agents/pharmacology
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Affiliation(s)
- Yun Liu
- Department of Biopharmaceutical Key Laboratory of Heilongjiang Province, College of Pharmacy, Harbin Medical University, 157 Baojian Road, Nangang District, Harbin, Heilongjiang 150081, PR China
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Dabertrand F, Nelson MT, Brayden JE. Acidosis dilates brain parenchymal arterioles by conversion of calcium waves to sparks to activate BK channels. Circ Res 2011; 110:285-94. [PMID: 22095728 DOI: 10.1161/circresaha.111.258145] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Acidosis is a powerful vasodilator signal in the brain circulation. However, the mechanisms by which this response occurs are not well understood, particularly in the cerebral microcirculation. One important mechanism to dilate cerebral (pial) arteries is by activation of large-conductance, calcium-sensitive potassium (BK(Ca)) channels by local Ca(2+) signals (Ca(2+) sparks) through ryanodine receptors (RyRs). However, the role of this pathway in the brain microcirculation is not known. OBJECTIVE The objectives of this study were to determine the mechanism by which acidosis dilates brain parenchymal arterioles (PAs) and to elucidate the roles of RyRs and BK(Ca) channels in this response. METHODS AND RESULTS Internal diameter and vascular smooth muscle cell Ca(2+) signals were measured in isolated pressurized murine PAs, using imaging techniques. In physiological pH (7.4), vascular smooth muscle cells exhibited primarily RyR-dependent Ca(2+) waves. Reducing external pH from 7.4 to 7.0 in both normocapnic and hypercapnic conditions decreased Ca(2+) wave activity, and dramatically increased Ca(2+) spark activity. Acidic pH caused a dilation of PAs which was inhibited by about 60% by BK(Ca) channel or RyR blockers, in a nonadditive manner. Similarly, dilator responses to acidosis were reduced by nearly 60% in arterioles from BK(Ca) channel knockout mice. Dilations induced by acidic pH were unaltered by inhibitors of K(ATP) channels or nitric oxide synthase. CONCLUSIONS These results support the novel concept that acidification, by converting Ca(2+) waves to sparks, leads to the activation of BK(Ca) channels to induce dilation of cerebral PAs.
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Affiliation(s)
- Fabrice Dabertrand
- University of Vermont College of Medicine, Department of Pharmacology, 89 Beaumont Avenue, B-303 Given Building, Burlington, VT 05405-0068, USA
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Deussen A, Ohanyan V, Jannasch A, Yin L, Chilian W. Mechanisms of metabolic coronary flow regulation. J Mol Cell Cardiol 2011; 52:794-801. [PMID: 22004900 DOI: 10.1016/j.yjmcc.2011.10.001] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 09/23/2011] [Accepted: 10/02/2011] [Indexed: 01/17/2023]
Abstract
Coronary blood flow is tightly adjusted to the oxygen requirements of the myocardium. The underlying control mechanisms keep coronary venous pO(2) at a rather constant level around 20mm Hg under a variety of physiological conditions. Because coronary flow may increase more than 5-fold during exercise without any signs of under- or overperfusion, coronary flow must be controlled, at least in part, in a feed forward manner. Likely metabolic factors contributing to feed forward control are carbon dioxide and reactive oxygen species. Adaptation of coronary flow to exercise under physiological conditions involves in addition to metabolic control feed forward neuronal and endothelium-dependent control. Under pathological conditions, e.g. vessel stenosis or anemia, or specific environmental conditions, e.g. high altitude exposure, cardiac oxygenation may become critical, especially if oxygen demand is increased during physical exercise. Under such conditions the fall of coronary pO(2) may directly result in opening of oxygen sensitive potassium or closure of calcium channels. Furthermore the fall of pO(2) results in the production of vasoactive metabolites, e.g. adenosine, nitric oxide or prostaglandins, and in proton accumulation. All of these adaptations support a reduction of coronary vessel resistance. This article is part of a Special Issue entitled "Coronoray Blood Flow".
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Affiliation(s)
- Andreas Deussen
- Department of Physiology, Medical Faculty Carl Gustav Carus, TU Dresden, Fetscherstr. 74, 01307 Dresden, Germany.
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Crimi E, Taccone FS, Infante T, Scolletta S, Crudele V, Napoli C. Effects of intracellular acidosis on endothelial function: an overview. J Crit Care 2011; 27:108-18. [PMID: 21798701 DOI: 10.1016/j.jcrc.2011.06.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 05/17/2011] [Accepted: 06/03/2011] [Indexed: 01/13/2023]
Abstract
The endothelium represents the largest functional organ in the human body playing an active role in vasoregulation, coagulation, inflammation, and microvascular permeability. Endothelium contributes to maintain vascular integrity, intravascular volume, and tissue oxygenation promoting inflammatory network response for local defense and repair. Acid-basis homeostasis is an important physiologic parameter that controls cell function, and changes in pH can influence vascular tone by regulating endothelium and vascular smooth muscle cells. This review presents a current perspective of the effects of intracellular acidosis on the function and the basic regulatory mechanisms of endothelial cells.
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Affiliation(s)
- Ettore Crimi
- Department of Anesthesia and Critical Care Medicine, Shands Hospital, University of Florida, Gainesville, FL 32608, USA
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Leffler CW, Parfenova H, Basuroy S, Jaggar JH, Umstot ES, Fedinec AL. Hydrogen sulfide and cerebral microvascular tone in newborn pigs. Am J Physiol Heart Circ Physiol 2011; 300:H440-7. [PMID: 21131483 PMCID: PMC3044062 DOI: 10.1152/ajpheart.00722.2010] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 11/22/2010] [Indexed: 11/22/2022]
Abstract
Hydrogen sulfide (H2S) is a gaseous signaling molecule that appears to be involved in numerous biological processes, including regulation of blood pressure and vascular tone. The present study is designed to address the hypothesis that H2S is a functionally significant, endogenous dilator in the newborn cerebrovascular circulation. In vivo experiments were conducted using newborn pigs with surgically implanted, closed, cranial windows. Topical application of H2S concentration-dependently (10(-6) to 2×10(-4) M) dilated pial arterioles. This dilation was blocked by glibenclamide (10(-6) M). L-cysteine, the substrate of the H2S-producing enzymes cystathionine γ-lyase (CSE) and cystathionine β-synthase (CBS), also dilated pial arterioles. The dilation to L-cysteine was blocked by the CSE inhibitor d,l-propargylglycine (PPG, 10 mM) but was unaffected by the CBS inhibitor amino-oxyacetate (AOA, 1 mM). Western blots detected CSE, but not CBS, in cerebral microvessels, whereas CBS is detected in brain parenchyma. Immunohistological CSE expression is predominantly vascular while CBS is expressed mainly in neurons and astrocytes. L-cysteine (5 mM) increased H2S concentration in cerebrospinal fluid (CSF), measured by GC-MS, from 561±205 to 2,783±818 nM before but not during treatment with PPG (1,030±70 to 622±78 nM). Dilation to hypercapnia was inhibited by PPG but not AOA. Hypercapnia increased CSF H2S concentration from 763±243 to 4,337±1789 nM before but not during PPG treatment (357±178 vs. 425±217 nM). These data show that H2S is a dilator of the newborn cerebral circulation and that endogenous CSE can produce sufficient H2S to decrease vascular tone. H2S appears to be a physiologically significant dilator in the cerebral circulation.
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Affiliation(s)
- Charles W Leffler
- Laboratory for Research in Neonatal Physiology, Department of Physiology, University of Tennessee Health Science Center, 894 Union Ave., Memphis, TN 38163, USA.
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Brenninkmeijer L, Kuehl C, Geldart AM, Arons E, Christou H. Heme oxygenase-1 does not mediate the effects of extracellular acidosis on vascular smooth muscle cell proliferation, migration, and susceptibility to apoptosis. J Vasc Res 2011; 48:285-96. [PMID: 21273783 DOI: 10.1159/000321555] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Accepted: 09/17/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Unbalanced vascular smooth muscle cell (VSMC) proliferation, migration, and apoptosis contribute to vascular disorders such as atherosclerosis, restenosis, and pulmonary hypertension. The effect of extracellular acidosis (EA) on VSMC homeostasis is incompletely understood but we previously reported that EA increases heme oxygenase-1 (HO-1) expression in VSMCs. Since HO-1 regulates VSMC proliferation and apoptosis we sought to define the role of HO-1 in VSMC responses to EA. METHODS Mouse aortic smooth muscle cells (MASMCs) were isolated from wild-type and HO-1-null mice. Cell proliferation and migration assays were done in a physiologic pH (7.4) or EA (pH 6.8). VSMC apoptosis in response to hydrogen peroxide was assessed by JC-1 staining, caspase-3 cleavage, annexin V, and Hoechst staining. RESULTS Wild-type MASMCs showed decreased proliferation and migration at pH 6.8 compared to pH 7.4. This observation was also true in HO-1-null MASMCs. Although wild-type and HO-1-null cells showed differences in the mode and kinetics of cell death, both genotypes exhibited increased susceptibility to hydrogen peroxide-induced apoptosis at pH 6.8 compared to 7.4. CONCLUSIONS EA inhibits VSMC proliferation and migration and increases susceptibility to oxidant-induced apoptosis. These effects of acidosis on VSMC homeostasis are independent of HO-1.
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Affiliation(s)
- Lineke Brenninkmeijer
- Division of Newborn Medicine, Brigham and Women's and Children's Hospitals and Harvard Medical School, Boston, MA 02215, USA
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42
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Mitochondrial injury underlies hyporeactivity of arterial smooth muscle in severe shock. Am J Hypertens 2011; 24:45-51. [PMID: 20940715 DOI: 10.1038/ajh.2010.184] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Our previous data showed membrane hyperpolarization of arteriolar smooth muscle cells (ASMCs) caused by adenosine triphosphate (ATP)-sensitive potassium channels (K(ATP)) activation contributed to vascular hyporeactivity in shock. Despite supply of oxygen and nutrients, vascular hyporeactivity to vasoconstrictor agents still remains, which may result from low ATP level. The study was designed to investigate shock-induced mitochondrial changes of rat ASMCs in the genesis and treatment of hypotension in severe shock. METHODS The animals were divided into four groups: controls, hemorrhagic shock, CsA+shock (preadministration of cyclosporin A before bleeding), and ATR+CsA+shock (preadministration of atractyloside, followed by CsA and bleeding). ASMCs were isolated and the ultrastructure and function of ASMC mitochondria and the vasoresponsiveness to norepinephrine (NE) was measured on microcirculatory preparations. RESULTS Ultrastructurally, the hemorrhagic shock group showed swollen mitochondria with poorly defined cristae. In this group, the number of ASMCs with low mitochondrial membrane potential (Δψ(m)) was increased by 49.7%, and the intracellular ATP level was reduced by 82.1%, which led to activation of K(ATP) plasma membrane channels with resultant ASMC hyperpolarization and low vasoreactivity. These changes were reduced in the CsA+shock group. When mitochondrial damage was aggravated by ATR in the ATR+CsA+shock group, the CsA did not protect. Compared to the shock group, vasoresponsiveness to NE was much improved in the CsA+shock group. CONCLUSIONS Mitochondrial ASMC dysfunction is involved in the genesis of reduced vasoreactivity in severe shock. Mitochondrial protection may therefore be a new approach in the treatment of shock-induced hypotension.
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Liu JP, Komachi M, Tomura H, Mogi C, Damirin A, Tobo M, Takano M, Nochi H, Tamoto K, Sato K, Okajima F. Ovarian cancer G protein-coupled receptor 1-dependent and -independent vascular actions to acidic pH in human aortic smooth muscle cells. Am J Physiol Heart Circ Physiol 2010; 299:H731-42. [PMID: 20622109 DOI: 10.1152/ajpheart.00977.2009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Atherosclerosis is a chronic inflammation disease characterized by acidic micromilieu and the accumulation of numerous bioactive lipid mediators, such as lysophosphatidic acid (LPA) and prostaglandins, in the atherosclerotic lesion. Chronic acidification induced various effects on vascular smooth muscle cells, but the molecular mechanisms underlying these effects remain unknown. In this study, we examine the role of proton-sensing ovarian cancer G protein-coupled receptor 1 (OGR1) in extracellular acidification-induced regulation of cyclooxygenase (COX)-2 induction, PGI(2) production, MAPK phosphatase (MKP)-1 expression, and plasminogen activator inhibitor (PAI)-1 expression and proliferation in human aortic smooth muscle cells (AoSMCs). Experiments with knockdown with small interfering RNA specific to OGR1 and specific inhibitors for G proteins showed that acidification-induced COX-2 expression, PGI(2) production, and MKP-1 expression, but not PAI-1 expression and inhibition of proliferation, were dependent on OGR1 and mainly mediated by G(q/11) protein. LPA remarkably enhanced, through the LPA(1) receptor/G(i) protein, the OGR1-mediated vascular actions to acidic pH. In conclusion, acidic pH-induced vascular actions of AoSMCs can be dissected to OGR1-dependent and -independent pathways: COX-2 expression, PGI(2) production, and MKP-1 expression are mediated by OGR1, but PAI-1 expression and inhibition of proliferation are not. LPA, which is usually thought to be a proatherogenic lipid mediator, may exert antiatherogenic actions under acidic micromilieu through cross-talk between LPA(1)/G(i) protein and OGR1/G(q/11) protein.
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Affiliation(s)
- Jin-Peng Liu
- Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
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Peltekova V, Engelberts D, Otulakowski G, Uematsu S, Post M, Kavanagh BP. Hypercapnic acidosis in ventilator-induced lung injury. Intensive Care Med 2010; 36:869-78. [PMID: 20213072 DOI: 10.1007/s00134-010-1787-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Accepted: 02/09/2010] [Indexed: 10/19/2022]
Abstract
RATIONALE Permissive hypercapnia is established in lung injury management. Therapeutic hypercapnia causes benefit or harm, depending on the context. Ventilator-associated lung injury has a wide spectrum of candidate mechanisms, affording multiple opportunities for intervention such as hypercapnia to exert benefit or harm. OBJECTIVES To confirm (1) that hypercapnia attenuates in vivo ventilator-induced lung injury (VILI); (2) biological plausibility of such protection (e.g., dose-response, time series, inflammatory profile); and (3) that the associated biochemical events are consistently beneficial. METHODS A mouse model of VILI was established in vivo. Injurious ventilation was established, hypercapnia applied and markers of inflammation measured. MEASUREMENTS Lung injury was quantified by gas exchange, elastance, microvascular leak, histology and levels of cytokines and eicosanoids, cyclooxygenase and tissue nitrotyrosine. MAIN RESULTS Injurious ventilation caused significant lung injury (mechanics, microvascular leak, histology) and release of inflammatory cytokines, chemokines and eicosanoids. Hypercapnia attenuated these responses, with dose-response and time-dependent effects. No adverse effects of hypercapnia were observed in controls. Hypercapnia suppressed the transcription (mRNA) and translation (protein) of the major inducible prostanoid-generating enzyme (COX-2), but the effects on the downstream eicosanoids were modest. However, hypercapnia significantly increased lung tissue nitrotyrosine-at PaCO(2) levels that were protective. CONCLUSIONS Hypercapnia provided consistent and biologically plausible in vivo protection against VILI, but elevated lung tissue levels of nitro-tyrosine as previously described in sepsis. Clinicians and those designing clinical trials need to be aware of the potential for detrimental effects when using hypercapnia in order to balance benefits versus harm with this approach.
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Affiliation(s)
- Vanya Peltekova
- Physiology and Experimental Medicine, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
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Shi W, Cui N, Wu Z, Yang Y, Zhang S, Gai H, Zhu D, Jiang C. Lipopolysaccharides up-regulate Kir6.1/SUR2B channel expression and enhance vascular KATP channel activity via NF-kappaB-dependent signaling. J Biol Chem 2010; 285:3021-9. [PMID: 19959479 PMCID: PMC2823456 DOI: 10.1074/jbc.m109.058313] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 12/01/2009] [Indexed: 12/31/2022] Open
Abstract
Sepsis is a severe medical condition causing a large number of deaths worldwide. Recent studies indicate that the septic susceptibility is attributable to the vascular ATP-sensitive K(+) (K(ATP)) channel. However, the mechanisms underlying the channel modulation in sepsis are still unclear. Here we show evidence for the modulation of vascular K(ATP) channel by septic pathogen lipopolysaccharides (LPS). In isolated mesenteric arterial rings, phenylephrine (PE) produced concentration-dependent vasoconstriction that was relaxed by pinacidil, a selective K(ATP) channel opener. The PE response was disrupted with a LPS treatment. In acutely dissociated aortic smooth myocytes the LPS treatment augmented K(ATP) channel activity, and hyperpolarized the cells. Quantitative PCR analysis showed that LPS raised Kir6.1 and SUR2B transcripts in a concentration-dependent manner, which was suppressed by transcriptional inhibition. Consistently, the same LPS treatment did not affect Kir6.1/SUR2B channels in a heterologous expression system. The LPS effect on Kir6.1 and SUR2B expression was abolished in the presence of NF-kappaB inhibitors. Several other Toll-like receptor ligands also stimulated Kir6.1 and SUR2B expression to a similar degree as LPS. Thus, the effect of LPS on vasodilation involves up-regulation of K(ATP) channel expression, in which the NF-kappaB-dependent signaling plays an important role.
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Affiliation(s)
- Weiwei Shi
- From the Department of Biology, Georgia State University, Atlanta, Georgia 30303 and
| | - Ningren Cui
- From the Department of Biology, Georgia State University, Atlanta, Georgia 30303 and
| | - Zhongying Wu
- From the Department of Biology, Georgia State University, Atlanta, Georgia 30303 and
| | - Yang Yang
- From the Department of Biology, Georgia State University, Atlanta, Georgia 30303 and
| | - Shuang Zhang
- the School of Pharmacy, Harbin Medical University, Harbin, Heilongjiang 150081, China
| | - Hongyu Gai
- From the Department of Biology, Georgia State University, Atlanta, Georgia 30303 and
| | - Daling Zhu
- the School of Pharmacy, Harbin Medical University, Harbin, Heilongjiang 150081, China
| | - Chun Jiang
- From the Department of Biology, Georgia State University, Atlanta, Georgia 30303 and
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Foster GE, Brugniaux JV, Pialoux V, Duggan CTC, Hanly PJ, Ahmed SB, Poulin MJ. Cardiovascular and cerebrovascular responses to acute hypoxia following exposure to intermittent hypoxia in healthy humans. J Physiol 2009; 587:3287-99. [PMID: 19417094 DOI: 10.1113/jphysiol.2009.171553] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Intermittent hypoxia (IH) is thought to be responsible for many of the long-term cardiovascular consequences associated with obstructive sleep apnoea (OSA). Experimental human models of IH can aid in investigating the pathophysiology of these cardiovascular complications. The purpose of this study was to determine the effects of IH on the cardiovascular and cerebrovascular response to acute hypoxia and hypercapnia in an experimental human model that simulates the hypoxaemia experienced by OSA patients. We exposed 10 healthy, male subjects to IH for 4 consecutive days. The IH profile involved 2 min of hypoxia (nadir = 45.0 mmHg) alternating with 2 min of normoxia (peak = 88.0 mmHg) for 6 h. The cerebral blood flow response and the pressor responses to hypoxia and hypercapnia were assessed after 2 days of sham exposure, after each day of IH, and 4 days following the discontinuation of IH. Nitric oxide derivatives were measured at baseline and following the last exposure to IH. After 4 days of IH, mean arterial pressure increased by 4 mmHg (P < 0.01), nitric oxide derivatives were reduced by 55% (P < 0.05), the pressor response to acute hypoxia increased (P < 0.01), and the cerebral vascular resistance response to hypoxia increased (P < 0.01). IH alters blood pressure and cerebrovascular regulation, which is likely to contribute to the pathogenesis of cardiovascular and cerebrovascular disease in patients with OSA.
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Affiliation(s)
- Glen E Foster
- Department of Physiology and Pharmacology, University of Calgary, Canada
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Guan J, Wu X, Arons E, Christou H. The p38 mitogen-activated protein kinase pathway is involved in the regulation of heme oxygenase-1 by acidic extracellular pH in aortic smooth muscle cells. J Cell Biochem 2009; 105:1298-306. [PMID: 18846504 DOI: 10.1002/jcb.21930] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Extracellular acidosis (EA) regulates Heme Oxygenase-1 (HO-1) expression in vascular smooth muscle cells via transcriptional and posttranscriptional mechanisms but the signaling pathways involved are not known. We examined the role of Mitogen-Activated Protein Kinase (MAPK) pathways in HO-1 regulation by EA. Primary rat aortic smooth muscle cells were exposed to EA or physiologic pH. Levels of the total and phosphorylated forms of p38, extracellular signal-regulated protein kinases1/2 (ERK1/2), c-Jun N-terminal kinases/stress-activated protein kinases (JNK1/2), and HO-1 protein were assessed by Western analysis and HO-1 mRNA levels were assessed by quantitative PCR. Inhibition of p38 MAPK was achieved with the chemical inhibitor SB203580, or adenoviral infection of a dominant-negative form of p38alpha. Phospho p38 MAPK activity was evaluated with an in vitro kinase activity assay. Binding of Activator Protein-1 (AP-1), a known target of MAPK pathways, was assessed by Electromobility shift assay (EMSA). EA induced phosphorylation of p38 MAPK in a biphasic manner while total p38 was unchanged. EA did not alter levels of phospho ERK 1/2 and phospho JNK 1/2. There was increased phospho p38 MAPK activity in the setting of EA which preceded the induction of HO-1. Inhibition of phospho p38 activity with either SB20358 or a dominant negative p38alpha oligonucleotide abrogated the induction of HO-1 by EA. Increased specific binding of AP-1 in the setting of EA was shown by EMSA. Increased phospho p38 activity precedes and likely mediates HO-1 induction by EA. Increased AP-1 binding may underlie the transcriptional regulation of HO-1 by EA.
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Affiliation(s)
- Jason Guan
- Division of Newborn Medicine, Brigham and Women's and Children's Hospitals, Boston, Massachusetts 02115, USA
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Abstract
Acidosis is a noxious condition associated with inflammation, ischaemia or defective acid containment. As a consequence, acid sensing has evolved as an important property of afferent neurons with unmyelinated and thinly myelinated nerve fibres. Protons evoke multiple currents in primary afferent neurons, which are carried by several acid-sensitive ion channels. Among these, acid-sensing ion channels (ASICs) and transient receptor potential (TRP) vanilloid-1 (TRPV1) ion channels have been most thoroughly studied. ASICs survey moderate decreases in extracellular pH, whereas TRPV1 is activated only by severe acidosis resulting in pH values below 6. Two-pore-domain K(+) (K(2P)) channels are differentially regulated by small deviations of extra- or intracellular pH from physiological levels. Other acid-sensitive channels include TRPV4, TRPC4, TRPC5, TRPP2 (PKD2L1), ionotropic purinoceptors (P2X), inward rectifier K(+) channels, voltage-activated K(+) channels, L-type Ca(2+) channels, hyperpolarization-activated cyclic nucleotide gated channels, gap junction channels, and Cl(-) channels. In addition, acid-sensitive G protein coupled receptors have also been identified. Most of these molecular acid sensors are expressed by primary sensory neurons, although to different degrees and in various combinations. Emerging evidence indicates that many of the acid-sensitive ion channels and receptors play a role in acid sensing, acid-induced pain and acid-evoked feedback regulation of homeostatic reactions. The existence and apparent redundancy of multiple pH surveillance systems attests to the concept that acid-base regulation is a vital issue for cell and tissue homeostasis. Since upregulation and overactivity of acid sensors appear to contribute to various forms of chronic pain, acid-sensitive ion channels and receptors are considered as targets for novel analgesic drugs. This approach will only be successful if the pathological implications of acid sensors can be differentiated pharmacologically from their physiological function.
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Affiliation(s)
- Peter Holzer
- Research Unit of Translational Neurogastroenterology, Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Universitätsplatz 4, 8010, Graz, Austria.
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Luo H, Chang Y, Cai H, Zou W, Wang D, Guo Q. The effect of hypercapnic acidosis preconditioning on rabbit myocardium. ACTA ACUST UNITED AC 2008; 28:706-10. [PMID: 19107372 DOI: 10.1007/s11596-008-0621-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2008] [Indexed: 01/09/2023]
Abstract
This study observed the protective effect of hypercapnic acidosis preconditioning on rabbit heart suffered from ischemia-reperfusion injury. Hypercapnic acidosis was established in animals with mechanical hypoventilation before ischemia-reperfusion. Thirty-two rabbits were randomly divided into 4 groups, with each having 8 animals in term of the degree of acidification: hypercapnic acidosis group A (group A), hypercapnic acidosis group B (group B), hypercapnic acidosis group C (group C), ischemia and reperfusion group (group IR). Animals in group IR were ventilated normally (tidal volume: 15 mL/kg, breathing rate 35 bpm). The PETCO(2) was maintained at the level of 40-50 mmHg for 30 min. Animals in groups A, B, C received low-frequency, low-volume ventilation to achieve hypercarbonic acidosis and the target levels of PETCO(2) were 75-85,65-75, 55-65 mmHg, respectively, with levels being maintained for 5 min. The animals then were ventilated normally to lower PETCO(2) to 40-50 mmHg. The left anterior branch artery of all the animals was ligated for 30 min and reperfused for 180 min. Then the infarct size was calculated. The cardiomyocytes were morphologically observed and ECG and hemodynamics were monitored on continuous basis. Acid-base balance was measured during procedure. Our results showed that the infarct size was (48.5+/-11.5)% of the risk area in the control group and (42.4+/-7.9)% in group C (P>0.05). Mean infarct size was significantly smaller in group B (34.5%+/-9.4%) (P<0.05 vs control group) and group A (31.0%+/-9.1%) (P<0.01 vs control group). It is concluded that HA-preconditioning can effectively protect the myocardium.
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Affiliation(s)
- Heguo Luo
- Department of Anesthesiology, the Second Xiangya Second Hospital of Central South University, Changsha, 410013, China.
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