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Wang AN, Fraser GM, McGuire JJ. Characterization of Endothelium-Dependent Relaxation in the Saphenous Artery and Its Caudal Branches in Young and Old Adult Sprague Dawley Rats. Biomolecules 2022; 12:biom12070889. [PMID: 35883445 PMCID: PMC9312764 DOI: 10.3390/biom12070889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/21/2022] [Accepted: 06/23/2022] [Indexed: 12/11/2022] Open
Abstract
Ageing is associated with reduced endothelium-derived nitric oxide (NO) production in the femoral artery of Sprague Dawley (SD) rats. In the current study, we examined endothelium-dependent relaxation (EDR) in the saphenous artery and its caudal branches. We used acetylcholine and the Proteinase-Activated receptor-2 (PAR2)-specific agonist (2fLIGRLO) with nitroarginine methylester (L-NAME) to assess EDR in two groups of male SD rats (age in weeks: young, 10–12; old, 27–29). Acetylcholine and 2fLIGRLO were potent NO-dependent relaxant agents in all arteries. For all arteries, EDR by acetylcholine decreased significantly in old compared to young SD rats. Interestingly, PAR2-induced EDR of proximal saphenous artery segments and caudal branches decreased significantly in old compared to young, but did not differ for the in-between middle and distal ends of the saphenous artery. L-NAME treatment increased subsequent contractions of proximal and middle segments of saphenous arteries by phenylephrine and U46619 in young, but not in old, SD rats. We conclude the SD saphenous artery and caudal branches exhibit regional characteristics that differ in response to specific EDR agonists, endothelial NO synthase inhibitor, and changes to endothelium function with increased age, which are, in part, attributed to decreased sensitivity of vascular smooth muscle to the gaseous transmitter NO.
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Affiliation(s)
- Andrea N. Wang
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada;
| | - Graham M. Fraser
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University, St. John’s, NL A1B 3V6, Canada;
| | - John J. McGuire
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada;
- Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada
- Correspondence:
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Gorshkova OP. Characteristics of Age-Related Changes in the Endothelium-Dependent Hyperpolarization of Pial Arteries in Normotensive and Spontaneously Hypertensive Rats. ADVANCES IN GERONTOLOGY 2021. [DOI: 10.1134/s2079057021030048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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3
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NOX5-induced uncoupling of endothelial NO synthase is a causal mechanism and theragnostic target of an age-related hypertension endotype. PLoS Biol 2020; 18:e3000885. [PMID: 33170835 PMCID: PMC7654809 DOI: 10.1371/journal.pbio.3000885] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 09/18/2020] [Indexed: 02/07/2023] Open
Abstract
Hypertension is the most important cause of death and disability in the elderly. In 9 out of 10 cases, the molecular cause, however, is unknown. One mechanistic hypothesis involves impaired endothelium-dependent vasodilation through reactive oxygen species (ROS) formation. Indeed, ROS forming NADPH oxidase (Nox) genes associate with hypertension, yet target validation has been negative. We re-investigate this association by molecular network analysis and identify NOX5, not present in rodents, as a sole neighbor to human vasodilatory endothelial nitric oxide (NO) signaling. In hypertensive patients, endothelial microparticles indeed contained higher levels of NOX5—but not NOX1, NOX2, or NOX4—with a bimodal distribution correlating with disease severity. Mechanistically, mice expressing human Nox5 in endothelial cells developed—upon aging—severe systolic hypertension and impaired endothelium-dependent vasodilation due to uncoupled NO synthase (NOS). We conclude that NOX5-induced uncoupling of endothelial NOS is a causal mechanism and theragnostic target of an age-related hypertension endotype. Nox5 knock-in (KI) mice represent the first mechanism-based animal model of hypertension. The causes of hypertension are not understood; treatments are symptomatic and prevent only few of the associated risks. This study applies network medicine to identify a subgroup of patients with NADPH oxidase 5-induced uncoupling of nitric oxide synthase as the cause of age-related hypertension, enabling a first-in-class mechanism-based treatment of hypertension.
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Serviente C, Berry CW, Kenney WL, Alexander LM. Healthy active older adults have enhanced K + channel-dependent endothelial vasodilatory mechanisms. Am J Physiol Regul Integr Comp Physiol 2020; 319:R19-R25. [PMID: 32401629 PMCID: PMC7468792 DOI: 10.1152/ajpregu.00049.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/10/2020] [Accepted: 05/11/2020] [Indexed: 12/21/2022]
Abstract
Microvascular endothelial dysfunction, a precursor to atherosclerotic cardiovascular disease, increases with aging. Endothelium-derived hyperpolarizing factors (EDHFs), which act through K+ channels, regulate blood flow and are important to vascular health. It is unclear how EDHFs change with healthy aging. To evaluate microvascular endothelial reliance on K+ channel-mediated dilation as a function of age in healthy humans. Microvascular function was assessed using intradermal microdialysis in healthy younger (Y; n = 7; 3 M/4 W; 26 ± 1 yr) and older adults (O; n = 12; 5 M/7 W; 64 ± 2 yr) matched for V̇o2peak (Y: 39.0 ± 3.8, O: 37.6 ± 3.1 mL·kg-1·min-1). Participants underwent graded local infusions of: the K+ channel activator Na2S (10-6 to 10-1 M), acetylcholine (ACh, 10-10 to 10-1 M), ACh + the K+ channel inhibitor tetraethylammonium (TEA; 25 or 50 mM), and ACh + the nitric oxide synthase-inhibitor l-NAME (15 mM). Red blood cell flux was measured with laser-Doppler flowmetry and used to calculate cutaneous vascular conductance (CVC; flux/mean arterial pressure) as a percentage of each site-specific maximum (%CVCmax, 43°C+28 mM sodium nitroprusside). The %CVCmax response to Na2S was higher in older adults (mean, O: 51.7 ± 3.9% vs. Y: 36.1 ± 5.3%; P = 0.03). %CVCmax was lower in the ACh+TEA vs. the ACh site starting at 10-5 M (ACh: 34.0 ± 5.7% vs. ACh+TEA: 19.4 ± 4.5%; P = 0.002) in older and at 10-4 M (ACh: 54.5 ± 9.4% vs. ACh+TEA: 31.2 ± 6.7%; P = 0.0002) in younger adults. %CVCmax was lower in the ACh+l-NAME vs. the ACh site in both groups starting at 10-4 M ACh (Y: P < 0.001; O: P = 0.02). Healthy active older adults have enhanced K+ channel-dependent endothelial vasodilatory mechanisms, suggesting increased responsiveness to EDHFs with age.
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Affiliation(s)
- Corinna Serviente
- Department of Kinesiology, Pennsylvania State University, University Park, Pennsylvania
- Center for Healthy Aging, Pennsylvania State University, University Park, Pennsylvania
| | - Craig W Berry
- Department of Kinesiology, Pennsylvania State University, University Park, Pennsylvania
| | - W Larry Kenney
- Department of Kinesiology, Pennsylvania State University, University Park, Pennsylvania
- Center for Healthy Aging, Pennsylvania State University, University Park, Pennsylvania
| | - Lacy M Alexander
- Department of Kinesiology, Pennsylvania State University, University Park, Pennsylvania
- Center for Healthy Aging, Pennsylvania State University, University Park, Pennsylvania
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Gorshkova OP, Shuvaeva VN. Age-Related Changes in the Role of
Calcium-Activated Potassium Channels in Acetylcholine Mediated Dilatation of Pial
Arterial Vessels in Rats. J EVOL BIOCHEM PHYS+ 2020. [DOI: 10.1134/s0022093020020064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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6
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Troidl K, Schubert C, Vlacil AK, Chennupati R, Koch S, Schütt J, Oberoi R, Schaper W, Schmitz-Rixen T, Schieffer B, Grote K. The Lipopeptide MALP-2 Promotes Collateral Growth. Cells 2020; 9:cells9040997. [PMID: 32316253 PMCID: PMC7227808 DOI: 10.3390/cells9040997] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 04/14/2020] [Indexed: 12/19/2022] Open
Abstract
Beyond their role in pathogen recognition and the initiation of immune defense, Toll-like receptors (TLRs) are known to be involved in various vascular processes in health and disease. We investigated the potential of the lipopeptide and TLR2/6 ligand macrophage activating protein of 2-kDA (MALP-2) to promote blood flow recovery in mice. Hypercholesterolemic apolipoprotein E (Apoe)-deficient mice were subjected to microsurgical ligation of the femoral artery. MALP-2 significantly improved blood flow recovery at early time points (three and seven days), as assessed by repeated laser speckle imaging, and increased the growth of pre-existing collateral arteries in the upper hind limb, along with intimal endothelial cell proliferation in the collateral wall and pericollateral macrophage accumulation. In addition, MALP-2 increased capillary density in the lower hind limb. MALP-2 enhanced endothelial nitric oxide synthase (eNOS) phosphorylation and nitric oxide (NO) release from endothelial cells and improved the experimental vasorelaxation of mesenteric arteries ex vivo. In vitro, MALP-2 led to the up-regulated expression of major endothelial adhesion molecules as well as their leukocyte integrin receptors and consequently enhanced the endothelial adhesion of leukocytes. Using the experimental approach of femoral artery ligation (FAL), we achieved promising results with MALP-2 to promote peripheral blood flow recovery by collateral artery growth.
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Affiliation(s)
- Kerstin Troidl
- Max-Planck-Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany; (R.C.); (W.S.)
- Department of Vascular and Endovascular Surgery, University Hospital Frankfurt, 60488 Frankfurt, Germany; (C.S.); (T.S.-R.)
- Correspondence:
| | - Christian Schubert
- Department of Vascular and Endovascular Surgery, University Hospital Frankfurt, 60488 Frankfurt, Germany; (C.S.); (T.S.-R.)
| | - Ann-Kathrin Vlacil
- Cardiology and Angiology, Philipps-University Marburg, 35043 Marburg, Germany; (A.-K.V.); (S.K.); (J.S.); (R.O.); (B.S.); (K.G.)
| | - Ramesh Chennupati
- Max-Planck-Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany; (R.C.); (W.S.)
| | - Sören Koch
- Cardiology and Angiology, Philipps-University Marburg, 35043 Marburg, Germany; (A.-K.V.); (S.K.); (J.S.); (R.O.); (B.S.); (K.G.)
| | - Jutta Schütt
- Cardiology and Angiology, Philipps-University Marburg, 35043 Marburg, Germany; (A.-K.V.); (S.K.); (J.S.); (R.O.); (B.S.); (K.G.)
| | - Raghav Oberoi
- Cardiology and Angiology, Philipps-University Marburg, 35043 Marburg, Germany; (A.-K.V.); (S.K.); (J.S.); (R.O.); (B.S.); (K.G.)
| | - Wolfgang Schaper
- Max-Planck-Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany; (R.C.); (W.S.)
| | - Thomas Schmitz-Rixen
- Department of Vascular and Endovascular Surgery, University Hospital Frankfurt, 60488 Frankfurt, Germany; (C.S.); (T.S.-R.)
| | - Bernhard Schieffer
- Cardiology and Angiology, Philipps-University Marburg, 35043 Marburg, Germany; (A.-K.V.); (S.K.); (J.S.); (R.O.); (B.S.); (K.G.)
| | - Karsten Grote
- Cardiology and Angiology, Philipps-University Marburg, 35043 Marburg, Germany; (A.-K.V.); (S.K.); (J.S.); (R.O.); (B.S.); (K.G.)
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7
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Behringer EJ, Hakim MA. Functional Interaction among K Ca and TRP Channels for Cardiovascular Physiology: Modern Perspectives on Aging and Chronic Disease. Int J Mol Sci 2019; 20:ijms20061380. [PMID: 30893836 PMCID: PMC6471369 DOI: 10.3390/ijms20061380] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/07/2019] [Accepted: 03/15/2019] [Indexed: 12/16/2022] Open
Abstract
Effective delivery of oxygen and essential nutrients to vital organs and tissues throughout the body requires adequate blood flow supplied through resistance vessels. The intimate relationship between intracellular calcium ([Ca2+]i) and regulation of membrane potential (Vm) is indispensable for maintaining blood flow regulation. In particular, Ca2+-activated K+ (KCa) channels were ascertained as transducers of elevated [Ca2+]i signals into hyperpolarization of Vm as a pathway for decreasing vascular resistance, thereby enhancing blood flow. Recent evidence also supports the reverse role for KCa channels, in which they facilitate Ca2+ influx into the cell interior through open non-selective cation (e.g., transient receptor potential; TRP) channels in accord with robust electrical (hyperpolarization) and concentration (~20,000-fold) transmembrane gradients for Ca2+. Such an arrangement supports a feed-forward activation of Vm hyperpolarization while potentially boosting production of nitric oxide. Furthermore, in vascular types expressing TRP channels but deficient in functional KCa channels (e.g., collecting lymphatic endothelium), there are profound alterations such as downstream depolarizing ionic fluxes and the absence of dynamic hyperpolarizing events. Altogether, this review is a refined set of evidence-based perspectives focused on the role of the endothelial KCa and TRP channels throughout multiple experimental animal models and vascular types. We discuss the diverse interactions among KCa and TRP channels to integrate Ca2+, oxidative, and electrical signaling in the context of cardiovascular physiology and pathology. Building from a foundation of cellular biophysical data throughout a wide and diverse compilation of significant discoveries, a translational narrative is provided for readers toward the treatment and prevention of chronic, age-related cardiovascular disease.
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Affiliation(s)
- Erik J Behringer
- Department of Basic Sciences, 11041 Campus Street, Risley Hall, Loma Linda University, Loma Linda, CA 92350, USA.
| | - Md A Hakim
- Department of Basic Sciences, 11041 Campus Street, Risley Hall, Loma Linda University, Loma Linda, CA 92350, USA.
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Chennupati R, Meens MJ, Janssen BJ, van Dijk P, Hakvoort TBM, Lamers WH, De Mey JGR, Koehler SE. Deletion of endothelial arginase 1 does not improve vasomotor function in diabetic mice. Physiol Rep 2018; 6:e13717. [PMID: 29890043 PMCID: PMC5995309 DOI: 10.14814/phy2.13717] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 04/29/2018] [Accepted: 04/30/2018] [Indexed: 01/08/2023] Open
Abstract
Endothelial arginase 1 was ablated to assess whether this prevents hyperglycemia-induced endothelial dysfunction by improving arginine availability for nitric oxide production. Endothelial Arg1-deficient mice (Arg1-KOTie2 ) were generated by crossing Arg1fl/fl (controls) with Tie2Cretg/- mice and analyzed by immunohistochemistry, measurements of hemodynamics, and wire myography. Ablation was confirmed by immunohistochemistry. Mean arterial blood pressure was similar in conscious male control and Arg1-KOTie2 mice. Depletion of circulating arginine by intravenous infusion of arginase 1 or inhibition of nitric oxide synthase activity with L-NG -nitro-arginine methyl ester increased mean arterial pressure similarly in control (9 ± 2 and 34 ± 2 mmHg, respectively) and Arg1-KOTie2 mice (11 ± 3 and 38 ± 4 mmHg, respectively). Vasomotor responses were studied in isolated saphenous arteries of 12- and 34-week-old Arg1-KOTie2 and control animals by wire myography. Diabetes was induced in 10-week-old control and Arg1-KOTie2 mice with streptozotocin, and vasomotor responses were studied 10 weeks later. Optimal arterial diameter, contractile responses to phenylephrine, and relaxing responses to acetylcholine and sodium nitroprusside were similar in normoglycemic control and Arg1-KOTie2 mice. The relaxing response to acetylcholine was dependent on the availability of extracellular l-arginine. In the diabetic mice, arterial relaxation responses to endothelium-dependent hyperpolarization and to exogenous nitric oxide were impaired. The data show that endothelial ablation of arginase 1 in mice does not markedly modify smooth muscle and endothelial functions of a resistance artery under normo- and hyperglycemic conditions.
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Affiliation(s)
- Ramesh Chennupati
- Departments of Anatomy & EmbryologyMaastricht UniversityMaastrichtthe Netherlands
- Department of Pharmacology & ToxicologyMaastricht UniversityMaastrichtthe Netherlands
- Cardiovascular Research Institute Maastricht (CARIM)Maastricht UniversityMaastrichtthe Netherlands
- Nutrim ‐ School of Nutrition and Translational Research in MetabolismMaastricht UniversityMaastrichtthe Netherlands
| | - Merlijn J. Meens
- Department of Pharmacology & ToxicologyMaastricht UniversityMaastrichtthe Netherlands
- Department of Pathology and ImmunologyUniversity of GenevaGenevaSwitzerland
| | - Ben J. Janssen
- Department of Pharmacology & ToxicologyMaastricht UniversityMaastrichtthe Netherlands
- Cardiovascular Research Institute Maastricht (CARIM)Maastricht UniversityMaastrichtthe Netherlands
| | - Paul van Dijk
- Departments of Anatomy & EmbryologyMaastricht UniversityMaastrichtthe Netherlands
| | | | - Wouter H. Lamers
- Departments of Anatomy & EmbryologyMaastricht UniversityMaastrichtthe Netherlands
- Nutrim ‐ School of Nutrition and Translational Research in MetabolismMaastricht UniversityMaastrichtthe Netherlands
| | - Jo G. R. De Mey
- Department of Pharmacology & ToxicologyMaastricht UniversityMaastrichtthe Netherlands
- Cardiovascular Research Institute Maastricht (CARIM)Maastricht UniversityMaastrichtthe Netherlands
- Department of Cardiovascular and Renal ResearchInstitute of Molecular MedicineUniversity of Southern DenmarkOdenseDenmark
- Department of CardiacThoracic and Vascular SurgeryOdense University HospitalOdenseDenmark
| | - S. Eleonore Koehler
- Departments of Anatomy & EmbryologyMaastricht UniversityMaastrichtthe Netherlands
- Nutrim ‐ School of Nutrition and Translational Research in MetabolismMaastricht UniversityMaastrichtthe Netherlands
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9
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Behringer EJ. Calcium and electrical signaling in arterial endothelial tubes: New insights into cellular physiology and cardiovascular function. Microcirculation 2018; 24. [PMID: 27801542 DOI: 10.1111/micc.12328] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 10/25/2016] [Indexed: 12/23/2022]
Abstract
The integral role of the endothelium during the coordination of blood flow throughout vascular resistance networks has been recognized for several decades now. Early examination of the distinct anatomy and physiology of the endothelium as a signaling conduit along the vascular wall has prompted development and application of an intact endothelial "tube" study model isolated from rodent skeletal muscle resistance arteries. Vasodilatory signals such as increased endothelial cell (EC) Ca2+ ([Ca2+ ]i ) and hyperpolarization take place in single ECs while shared between electrically coupled ECs through gap junctions up to distances of millimeters (≥2 mm). The small- and intermediate-conductance Ca2+ activated K+ (SKCa /IKCa or KCa 2.3/KCa 3.1) channels function at the interface of Ca2+ signaling and hyperpolarization; a bidirectional relationship whereby increases in [Ca2+ ]i activate SKCa /IKCa channels to produce hyperpolarization and vice versa. Further, the spatial domain of hyperpolarization among electrically coupled ECs can be finely tuned via incremental modulation of SKCa /IKCa channels to balance the strength of local and conducted electrical signals underlying vasomotor activity. Multifunctional properties of the voltage-insensitive SKCa /IKCa channels of resistance artery endothelium may be employed for therapy during the aging process and development of vascular disease.
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Affiliation(s)
- Erik J Behringer
- Department of Basic Sciences, Loma Linda University, Loma Linda, CA, USA
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10
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Mathew John C, Khaddaj Mallat R, George G, Kim T, Mishra RC, Braun AP. Pharmacologic targeting of endothelial Ca 2+-activated K + channels: A strategy to improve cardiovascular function. Channels (Austin) 2018; 12:126-136. [PMID: 29577810 PMCID: PMC5972810 DOI: 10.1080/19336950.2018.1454814] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 03/15/2018] [Indexed: 12/17/2022] Open
Abstract
Endothelial small and intermediate-conductance, Ca2+-activated K+ channels (KCa2.3 and KCa3.1, respectively) play an important role in the regulation of vascular function and systemic blood pressure. Growing evidence indicates that they are intimately involved in agonist-evoked vasodilation of small resistance arteries throughout the circulation. Small molecule activators of KCa2.x and 3.1 channels, such as SKA-31, can acutely inhibit myogenic tone in isolated resistance arteries, induce effective vasodilation in intact vascular beds, such as the coronary circulation, and acutely decrease systemic blood pressure in vivo. The blood pressure-lowering effect of SKA-31, and early indications of improvement in endothelial dysfunction suggest that endothelial KCa channel activators could eventually be developed into a new class of endothelial targeted agents to combat hypertension or atherosclerosis. This review summarises recent insights into the activation of endothelial Ca2+ activated K+ channels in various vascular beds, and how tools, such as SKA-31, may be beneficial in disease-related conditions.
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Affiliation(s)
- Cini Mathew John
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Rayan Khaddaj Mallat
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Grace George
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Taeyeob Kim
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Ramesh C. Mishra
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Andrew P. Braun
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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11
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Behringer EJ, Segal SS. Impact of Aging on Calcium Signaling and Membrane Potential in Endothelium of Resistance Arteries: A Role for Mitochondria. J Gerontol A Biol Sci Med Sci 2017; 72:1627-1637. [PMID: 28510636 DOI: 10.1093/gerona/glx079] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 04/21/2017] [Indexed: 12/20/2022] Open
Abstract
Impaired blood flow to peripheral tissues during advanced age is associated with endothelial dysfunction and diminished bioavailability of nitric oxide (NO). However, it is unknown whether aging impacts coupling between intracellular calcium ([Ca2+]i) signaling and small- and intermediate K+ channel (SKCa/IKCa) activity during endothelium-derived hyperpolarization (EDH), a signaling pathway integral to dilation of the resistance vasculature. To address the potential impact of aging on EDH, Fura-2 photometry and intracellular recording were applied to evaluate [Ca2+]i and membrane potential of intact endothelial tubes (width, 60 µm; length, 1-3 mm) freshly isolated from superior epigastric arteries of young (4-6 mo) and old (24-26 mo) male C57BL/6 mice. In response to acetylcholine, intracellular release of Ca2+ from the endoplasmic reticulum (ER) was enhanced with aging. Further, treatment with the mitochondrial uncoupler FCCP evoked a significant increase of [Ca2+]i with membrane hyperpolarization in an SKCa/IKCa-dependent manner in the endothelium of old but not young mice. We conclude that the ability of resistance artery endothelium to release Ca2+ from intracellular stores (ie, ER and mitochondria) and hyperpolarize Vm via SKCa/IKCa activation is augmented as compensation for reduced NO bioavailability during advanced age.
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Affiliation(s)
- Erik J Behringer
- Department of Basic Sciences, Loma Linda University, California.,Department of Medical Pharmacology and Physiology, University of Missouri, Columbia
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia.,Dalton Cardiovascular Research Center, Columbia, Missouri
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12
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Wu K, Zhang Q, Wu X, Lu W, Tang H, Liang Z, Gu Y, Song S, Ayon RJ, Wang Z, McDermott KM, Balistrieri A, Wang C, Black SM, Garcia JGN, Makino A, Yuan JXJ, Wang J. Chloroquine is a potent pulmonary vasodilator that attenuates hypoxia-induced pulmonary hypertension. Br J Pharmacol 2017; 174:4155-4172. [PMID: 28849593 DOI: 10.1111/bph.13990] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 08/09/2017] [Accepted: 08/14/2017] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Sustained pulmonary vasoconstriction and excessive pulmonary vascular remodelling are two major causes of elevated pulmonary vascular resistance in patients with pulmonary arterial hypertension. The purpose of this study was to investigate whether chloroquine induced relaxation in the pulmonary artery (PA) and attenuates hypoxia-induced pulmonary hypertension (HPH). EXPERIMENTAL APPROACH Isometric tension was measured in rat PA rings pre-constricted with phenylephrine or high K+ solution. PA pressure was measured in mouse isolated, perfused and ventilated lungs. Fura-2 fluorescence microscopy was used to measure cytosolic free Ca2+ concentration levels in PA smooth muscle cells (PASMCs). Patch-clamp experiments were performed to assess the activity of voltage-dependent Ca2+ channels (VDCCs) in PASMC. Rats exposed to hypoxia (10% O2 ) for 3 weeks were used as the model of HPH or Sugen5416/hypoxia (SuHx) for in vivo experiments. KEY RESULTS Chloroquine attenuated agonist-induced and high K+ -induced contraction in isolated rat PA. Pretreatment with l-NAME or indomethacin and functional removal of endothelium failed to inhibit chloroquine-induced PA relaxation. In PASMC, extracellular application of chloroquine attenuated store-operated Ca2+ entry and ATP-induced Ca2+ entry. Furthermore, chloroquine also inhibited whole-cell Ba2+ currents through VDCC in PASMC. In vivo experiments demonstrated that chloroquine treatment ameliorated the HPH and SuHx models. CONCLUSIONS AND IMPLICATIONS Chloroquine is a potent pulmonary vasodilator that may directly or indirectly block VDCC, store-operated Ca2+ channels and receptor-operated Ca2+ channels in PASMC. The therapeutic potential of chloroquine in pulmonary hypertension is probably due to the combination of its vasodilator, anti-proliferative and anti-autophagic effects.
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Affiliation(s)
- Kang Wu
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Qian Zhang
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Physiology, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Xiongting Wu
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Wenju Lu
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Haiyang Tang
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Zhihao Liang
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Yali Gu
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Shanshan Song
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Ramon J Ayon
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Ziyi Wang
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Kimberly M McDermott
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Angela Balistrieri
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Christina Wang
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Stephen M Black
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Physiology, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Joe G N Garcia
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Ayako Makino
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Physiology, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Jason X-J Yuan
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Physiology, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Jian Wang
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
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13
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Leurgans TM, Bloksgaard M, Irmukhamedov A, Riber LP, De Mey JGR. Relaxing Responses to Hydrogen Peroxide and Nitric Oxide in Human Pericardial Resistance Arteries Stimulated with Endothelin-1. Basic Clin Pharmacol Toxicol 2017; 122:74-81. [PMID: 28686356 DOI: 10.1111/bcpt.12843] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 07/04/2017] [Indexed: 12/13/2022]
Abstract
In human pericardial resistance arteries, effects of the endothelium-dependent vasodilator bradykinin are mediated by NO during contraction induced by K+ or the TxA2 analogue U46619 and by H2 O2 during contraction by endothelin-1 (ET-1), respectively. We tested the hypotheses that ET-1 reduces relaxing effects of NO and increases those of H2 O2 in resistance artery smooth muscle of patients with cardiovascular disease. Arterial segments, dissected from the parietal pericardium of 39 cardiothoracic surgery patients, were studied by myography during amplitude-matched contractions induced by K+ , the TXA2 analogue U46619 or ET-1. Effects of the NO donor Na-nitroprusside (SNP) and of exogenous H2 O2 were recorded in the absence and presence of inhibitors of cyclooxygenases, NO synthases and small and intermediate conductance calcium-activated K+ channels. During contractions induced by either of the three stimuli, the potency of SNP did not differ and was not modified by the inhibitors. In vessels contracted with ET-1, the potency of H2 O2 was on average and in terms of interindividual variability considerably larger than in K+ -contracted vessels. Both differences were not statistically significant in the presence of inhibitors of mechanisms of endothelium-dependent vasodilatation. In resistance arteries from patients with cardiovascular disease, ET-1 does not selectively modify smooth muscle relaxing responses to NO or H2 O2 . Furthermore, the candidate endothelium-derived relaxing factor H2 O2 also acts as an endothelium-dependent vasodilator.
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Affiliation(s)
- Thomas M Leurgans
- Department of Cardiovascular and Renal Research, Centre for Individualized Medicine in Arterial Diseases (CIMA), Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Maria Bloksgaard
- Department of Cardiovascular and Renal Research, Centre for Individualized Medicine in Arterial Diseases (CIMA), Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Akhmadjon Irmukhamedov
- Department of Cardiac, Thoracic and Vascular Surgery, Centre for Individualized Medicine in Arterial Diseases (CIMA), Odense University Hospital, Odense, Denmark
| | - Lars P Riber
- Department of Cardiac, Thoracic and Vascular Surgery, Centre for Individualized Medicine in Arterial Diseases (CIMA), Odense University Hospital, Odense, Denmark
| | - Jo G R De Mey
- Department of Cardiovascular and Renal Research, Centre for Individualized Medicine in Arterial Diseases (CIMA), Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Cardiac, Thoracic and Vascular Surgery, Centre for Individualized Medicine in Arterial Diseases (CIMA), Odense University Hospital, Odense, Denmark.,Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
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14
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Matsumoto T, Kobayashi S, Ando M, Watanabe S, Iguchi M, Taguchi K, Kobayashi T. Impaired endothelium-derived hyperpolarization-type relaxation in superior mesenteric arteries isolated from female Otsuka Long-Evans Tokushima Fatty rats. Eur J Pharmacol 2017; 807:151-158. [PMID: 28433656 DOI: 10.1016/j.ejphar.2017.03.062] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 02/27/2017] [Accepted: 03/31/2017] [Indexed: 01/27/2023]
Abstract
Endothelium-derived hyperpolarization (EDH) is an important signaling mechanism of endothelium-dependent vasorelaxation, and little attention has been paid to the EDH-type responses in female metabolic syndrome such as that observed with type-2 diabetes. We previously reported that EDH-type relaxation was impaired in superior mesenteric arteries from male Otsuka Long-Evans Tokushima Fatty (OLETF) rat, a model of type-2 diabetes, however, the response was unclear in female OLETF rat. Thus, the aim of this study was to examine if EDH-type relaxation was altered in superior mesenteric arteries isolated from female OLETF rats compared to age-matched, control female Long-Evans Tokushima Otsuka (LETO) rats at age 50-59 weeks. We investigated concentration-relaxation curves for acetylcholine (at age 50-53 weeks), NS309 (an activator of small- and intermediate-conductance calcium-activated potassium channels) (at age 50-53 weeks), and GSK1016790A (an agonist of transient receptor potential vanilloid type 4, TRPV4) (at age 58 or 59 weeks) in the presence of the nitric oxide synthase inhibitor NG-nitro-L-arginine and the cyclooxygenase inhibitor indomethacin to investigate EDH-type responses in the superior mesenteric artery. Obesity, mild hyperglycemia, hyperinsulinemia, and hyperlipidemia (i.e., increased total cholesterol, triglyceride, and non-esterified fatty acids) were more frequent in OLETF rats than in age-matched LETO rats at age 50-53 weeks. Acetylcholine-, NS309-, and GSK1016790A-induced relaxations in arteries from OLETF rats were all significantly reduced compared to those in LETO rats. These results indicated that EDH-type relaxations were impaired in female OLETF rats. This novel experimental model may provide new insights into vascular dysfunction in metabolic syndrome in females.
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Affiliation(s)
- Takayuki Matsumoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Shota Kobayashi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Makoto Ando
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Shun Watanabe
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Maika Iguchi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Kumiko Taguchi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Tsuneo Kobayashi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan.
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15
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Vanhoutte PM, Shimokawa H, Feletou M, Tang EHC. Endothelial dysfunction and vascular disease - a 30th anniversary update. Acta Physiol (Oxf) 2017; 219:22-96. [PMID: 26706498 DOI: 10.1111/apha.12646] [Citation(s) in RCA: 556] [Impact Index Per Article: 79.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 10/27/2015] [Accepted: 12/17/2015] [Indexed: 02/06/2023]
Abstract
The endothelium can evoke relaxations of the underlying vascular smooth muscle, by releasing vasodilator substances. The best-characterized endothelium-derived relaxing factor (EDRF) is nitric oxide (NO) which activates soluble guanylyl cyclase in the vascular smooth muscle cells, with the production of cyclic guanosine monophosphate (cGMP) initiating relaxation. The endothelial cells also evoke hyperpolarization of the cell membrane of vascular smooth muscle (endothelium-dependent hyperpolarizations, EDH-mediated responses). As regards the latter, hydrogen peroxide (H2 O2 ) now appears to play a dominant role. Endothelium-dependent relaxations involve both pertussis toxin-sensitive Gi (e.g. responses to α2 -adrenergic agonists, serotonin, and thrombin) and pertussis toxin-insensitive Gq (e.g. adenosine diphosphate and bradykinin) coupling proteins. New stimulators (e.g. insulin, adiponectin) of the release of EDRFs have emerged. In recent years, evidence has also accumulated, confirming that the release of NO by the endothelial cell can chronically be upregulated (e.g. by oestrogens, exercise and dietary factors) and downregulated (e.g. oxidative stress, smoking, pollution and oxidized low-density lipoproteins) and that it is reduced with ageing and in the course of vascular disease (e.g. diabetes and hypertension). Arteries covered with regenerated endothelium (e.g. following angioplasty) selectively lose the pertussis toxin-sensitive pathway for NO release which favours vasospasm, thrombosis, penetration of macrophages, cellular growth and the inflammatory reaction leading to atherosclerosis. In addition to the release of NO (and EDH, in particular those due to H2 O2 ), endothelial cells also can evoke contraction of the underlying vascular smooth muscle cells by releasing endothelium-derived contracting factors. Recent evidence confirms that most endothelium-dependent acute increases in contractile force are due to the formation of vasoconstrictor prostanoids (endoperoxides and prostacyclin) which activate TP receptors of the vascular smooth muscle cells and that prostacyclin plays a key role in such responses. Endothelium-dependent contractions are exacerbated when the production of nitric oxide is impaired (e.g. by oxidative stress, ageing, spontaneous hypertension and diabetes). They contribute to the blunting of endothelium-dependent vasodilatations in aged subjects and essential hypertensive and diabetic patients. In addition, recent data confirm that the release of endothelin-1 can contribute to endothelial dysfunction and that the peptide appears to be an important contributor to vascular dysfunction. Finally, it has become clear that nitric oxide itself, under certain conditions (e.g. hypoxia), can cause biased activation of soluble guanylyl cyclase leading to the production of cyclic inosine monophosphate (cIMP) rather than cGMP and hence causes contraction rather than relaxation of the underlying vascular smooth muscle.
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Affiliation(s)
- P. M. Vanhoutte
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Pharmacology and Pharmacy; Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong City Hong Kong
| | - H. Shimokawa
- Department of Cardiovascular Medicine; Tohoku University; Sendai Japan
| | - M. Feletou
- Department of Cardiovascular Research; Institut de Recherches Servier; Suresnes France
| | - E. H. C. Tang
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Pharmacology and Pharmacy; Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong City Hong Kong
- School of Biomedical Sciences; Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong City Hong Kong
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16
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Coleman HA, Tare M, Parkington HC. Nonlinear effects of potassium channel blockers on endothelium-dependent hyperpolarization. Acta Physiol (Oxf) 2017; 219:324-334. [PMID: 27639255 DOI: 10.1111/apha.12805] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 02/12/2016] [Accepted: 09/13/2016] [Indexed: 12/17/2022]
Abstract
In a number of published studies on endothelium-dependent hyperpolarization and relaxation, the results of the effects of K+ blockers have been difficult to interpret. When the effects of two blockers have been studied, often either blocker by itself had little effect, whereas the two blockers combined tended to abolish the responses. Explanations suggested in the literature include an unusual pharmacology of the K+ channels, and possible blocker binding interactions. In contrast, when we applied the same blockers to segments of small blood vessels under voltage clamp, the blockers reduced the endothelium-dependent K+ current in a linearly additive manner. Resolution of these contrasting results is important as endothelium-derived hyperpolarization (EDH) makes its greatest contribution to vasorelaxation in arterioles and small resistance arteries, where it can exert a significant role in tissue perfusion and blood pressure regulation. Furthermore, EDH is impaired in various diseases. Here, we consider why the voltage-clamp results differ from earlier free-running membrane potential and contractility studies. We fitted voltage-clamp-derived current-voltage relationships with mathematical functions and considered theoretically the effects of partial and total block of endothelium-derived K+ -currents on the membrane potential of small blood vessels. When the K+ -conductance was partially reduced, equivalent to applying a single blocker, the effect on EDH was small. Total block of the endothelium-dependent K+ conductance abolished the hyperpolarization, in agreement with various published studies. We conclude that nonlinear summation of the hyperpolarizing response evoked by endothelial stimulation can explain the variable effectiveness of individual K+ channel blockers on endothelium-dependent hyperpolarization and resulting relaxation.
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Affiliation(s)
- H. A. Coleman
- Department of Physiology; Biomedicine Discovery Institute; Cardiovascular Disease Program; Monash University; Clayton Vic. Australia
| | - M. Tare
- Department of Physiology; Biomedicine Discovery Institute; Cardiovascular Disease Program; Monash University; Clayton Vic. Australia
| | - H. C. Parkington
- Department of Physiology; Biomedicine Discovery Institute; Cardiovascular Disease Program; Monash University; Clayton Vic. Australia
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17
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Leung SWS, Vanhoutte PM. Endothelium-dependent hyperpolarization: age, gender and blood pressure, do they matter? Acta Physiol (Oxf) 2017; 219:108-123. [PMID: 26548576 DOI: 10.1111/apha.12628] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Revised: 09/21/2015] [Accepted: 11/02/2015] [Indexed: 12/14/2022]
Abstract
Under physiological conditions, the endothelium generates vasodilator signals [prostacyclin, nitric oxide NO and endothelium-dependent hyperpolarization (EDH)], for the regulation of vascular tone. The relative importance of these two signals depends on the diameter of the blood vessels: as the diameter of the arteries decreases, the contribution of EDH to the regulation of vascular tone increases. The mechanism involved in EDH varies with species and blood vessel types; nevertheless, activation of endothelial intermediate- and small-conductance calcium-activated potassium channels (IKCa and SKCa , respectively) is characteristic of the EDH pathway. IKCa - and SKCa -mediated EDH are reduced with endothelial dysfunction, which develops with ageing and hypertension, and is less pronounced in female than in age-matched male until after menopause. Impaired EDH-mediated relaxation is related to a reduced involvement of SKCa , so that the response becomes more dependent on IKCa . The latter depends on the activation of adenosine monophosphate-activated protein kinase (AMPK) and silent information regulator T1 (SIRT1), proteins associated with the process of cellular senescence and vascular signalling in response to the female hormone. An understanding of the role of AMPK and/or SIRT1 in EDH-like responses may help identifying effective pharmacological strategies to prevent the development of vascular complications of different aetiologies.
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Affiliation(s)
- S. W. S. Leung
- Department of Pharmacology & Pharmacy; University of Hong Kong; Hong Kong Hong Kong SAR China
| | - P. M. Vanhoutte
- Department of Pharmacology & Pharmacy; University of Hong Kong; Hong Kong Hong Kong SAR China
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18
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19
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Non-steroidal anti-inflammatory drugs attenuate the vascular responses in aging metabolic syndrome rats. Acta Pharmacol Sin 2014; 35:1364-74. [PMID: 25263337 DOI: 10.1038/aps.2014.67] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 04/21/2014] [Indexed: 12/25/2022] Open
Abstract
AIM Metabolic syndrome (MS) and aging are low-grade systemic inflammatory conditions, and inflammation is a key component of endothelial dysfunction. The aim of this study was to investigate the effects of non-steroidal anti-inflammatory drugs (NSAIDs) upon the vascular reactivity in aging MS rats. METHODS MS was induced in young male rats by adding 30% sucrose in drinking water over 6, 12, and 18 months. When the treatment was finished, the blood samples were collected, and aortas were dissected out. The expression of COX isoenzymes and PLA2 in the aortas was analyzed using Western blot analysis. The contractile responses of aortic rings to norepinephrine (1 μmol/L) were measured in the presence or absence of different NSAIDs (10 μmol/L for each). RESULTS Serum levels of pro-inflammatory cytokines (IL-6, TNF-α, and IL-1β) in control rats were remained stable during the aging process, whereas serum IL-6 in MS rats were significantly increased at 12 and 18 months. The levels of COX isoenzyme and PLA2 in aortas from control rats increased with the aging, whereas those in aortas from MS rats were irregularly increased with the highest levels at 6 months. Pretreatment with acetylsalicylic acid (a COX-1 preferential inhibitor), indomethacin (a non-selective COX inhibitor) or meloxicam (a COX-2 preferential inhibitor) decreased NE-induced contractions of aortic rings from MS rats at all the ages, with meloxicam being the most potent. Acetylsalicylic acid also significantly reduced the maximum responses of ACh-induced vasorelaxation of aortic rings from MS rats, but indomethacin and meloxicam had no effect. CONCLUSION NSAIDs can directly affect vascular responses in aging MS rats. Understanding the effects of NSAIDs on blood vessels may improve the treatment of cardiovascular diseases and MS in the elders.
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20
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Endothelial arginine resynthesis contributes to the maintenance of vasomotor function in male diabetic mice. PLoS One 2014; 9:e102264. [PMID: 25033204 PMCID: PMC4102520 DOI: 10.1371/journal.pone.0102264] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 06/16/2014] [Indexed: 02/06/2023] Open
Abstract
Aim Argininosuccinate synthetase (ASS) is essential for recycling L-citrulline, the by-product of NO synthase (NOS), to the NOS substrate L-arginine. Here, we assessed whether disturbed arginine resynthesis modulates endothelium-dependent vasodilatation in normal and diabetic male mice. Methods and Results Endothelium-selective Ass-deficient mice (Assfl/fl/Tie2Cretg/− = Ass-KOTie2) were generated by crossing Assfl/fl mice ( = control) with Tie2Cre mice. Gene ablation in endothelial cells was confirmed by immunohistochemistry. Blood pressure (MAP) was recorded in 34-week-old male mice. Vasomotor responses were studied in isolated saphenous arteries of 12- and 34-week-old Ass-KOTie2 and control animals. At the age of 10 weeks, diabetes was induced in control and Ass-KOTie2 mice by streptozotocin injections. Vasomotor responses of diabetic animals were studied 10 weeks later. MAP was similar in control and Ass-KOTie2 mice. Depletion of circulating L-arginine by arginase 1 infusion or inhibition of NOS activity with L-NAME resulted in an increased MAP (10 and 30 mmHg, respectively) in control and Ass-KOTie2 mice. Optimal arterial diameter, contractile responses to phenylephrine, and relaxing responses to acetylcholine and sodium nitroprusside were similar in healthy control and Ass-KOTie2 mice. However, in diabetic Ass-KOTie2 mice, relaxation responses to acetylcholine and endothelium-derived NO (EDNO) were significantly reduced when compared to diabetic control mice. Conclusions Absence of endothelial citrulline recycling to arginine did not affect blood pressure and systemic arterial vasomotor responses in healthy mice. EDNO-mediated vasodilatation was significantly more impaired in diabetic Ass-KOTie2 than in control mice demonstrating that endothelial arginine recycling becomes a limiting endothelial function in diabetes.
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21
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Waeckel L, Bertin F, Clavreul N, Damery T, Köhler R, Paysant J, Sansilvestri-Morel P, Simonet S, Vayssettes-Courchay C, Wulff H, Verbeuren TJ, Félétou M. Preserved regulation of renal perfusion pressure by small and intermediate conductance KCa channels in hypertensive mice with or without renal failure. Pflugers Arch 2014; 467:817-31. [DOI: 10.1007/s00424-014-1542-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 05/19/2014] [Accepted: 05/19/2014] [Indexed: 11/29/2022]
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Feher A, Broskova Z, Bagi Z. Age-related impairment of conducted dilation in human coronary arterioles. Am J Physiol Heart Circ Physiol 2014; 306:H1595-601. [PMID: 24778172 DOI: 10.1152/ajpheart.00179.2014] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Conducted vasodilation is essential to coordinate vascular resistance along distances to ensure adequate tissue perfusion. We hypothesized that conducted vasodilation of coronary resistance arteries declines with age. Coronary arterioles were dissected from right atrial appendage of patients (n = 27) undergoing cardiac surgery. Arterioles (~100 μm) were cannulated and pressurized (80 mmHg), and developed spontaneous myogenic tone. Conducted vasodilation was initiated by locally administering the endothelium-dependent agonist bradykinin (BK; 100 μM) ejected from a glass micropipette (~3 μm tip opening, positioned in close proximity to the vessel wall). Diameter changes were measured at local and upstream sites (500 and 1,000 μm from the stimulus) with videomicroscopy. Local administration of BK elicited vasodilation, the magnitude of which increased with the duration of stimulus (69 ± 6, 81 ± 6, 90 ± 2%, after 1, 3, and 5 × 100 ms, respectively). BK-induced dilation remained substantial at upstream sites (500 μm: 53 ± 7%; 1,000 μm: 46 ± 9%). The gap junction uncoupler carbenoxolone or 18-α-glycyrrhetinic acid did not affect local responses, but diminished conducted vasodilation. Inhibitors of small/intermediate conductance calcium-activated potassium channels (SKCa/IKCa), apamin and TRAM34, reduced dilations both at local and remote sites. We found that conducted dilation, but not the local response, was significantly reduced in older (≥64 yr) patients. The nitric oxide (NO) synthesis inhibitor N(ω)-nitro-l-arginine methyl ester did not affect local responses, but markedly reduced conducted dilation in younger (<64 yr) individuals. Collectively, we show that human coronary arterioles exhibit SKCa/IKCa-mediated hyperpolarization spread through gap junctions, which contributes to conducted vasodilation initiated by focal application of BK. We demonstrate that conducted dilation declines with age, likely due to reduced NO availability, which plays a permissive role in propagating longitudinal vasomotor signaling.
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Affiliation(s)
- Attila Feher
- Vascular Biology Center, Medical College of Georgia, Georgia Regents University, Augusta, Georgia
| | - Zuzana Broskova
- Vascular Biology Center, Medical College of Georgia, Georgia Regents University, Augusta, Georgia
| | - Zsolt Bagi
- Vascular Biology Center, Medical College of Georgia, Georgia Regents University, Augusta, Georgia
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23
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El Assar M, Angulo J, Rodríguez-Mañas L. Oxidative stress and vascular inflammation in aging. Free Radic Biol Med 2013; 65:380-401. [PMID: 23851032 DOI: 10.1016/j.freeradbiomed.2013.07.003] [Citation(s) in RCA: 397] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 06/28/2013] [Accepted: 07/02/2013] [Indexed: 12/13/2022]
Abstract
Vascular aging, a determinant factor for cardiovascular disease and health status in the elderly, is now viewed as a modifiable risk factor. Impaired endothelial vasodilation is a early hallmark of arterial aging that precedes the clinical manifestations of vascular dysfunction, the first step to cardiovascular disease and influencing vascular outcomes in the elderly. Accordingly, the preservation of endothelial function is thought to be an essential determinant of healthy aging. With special attention on the effects of aging on the endothelial function, this review is focused on the two main mechanisms of aging-related endothelial dysfunction: oxidative stress and inflammation. Aging vasculature generates an excess of the reactive oxygen species (ROS), superoxide and hydrogen peroxide, that compromise the vasodilatory activity of nitric oxide (NO) and facilitate the formation of the deleterious radical, peroxynitrite. Main sources of ROS are mitochondrial respiratory chain and NADPH oxidases, although NOS uncoupling could also account for ROS generation. In addition, reduced antioxidant response mediated by erythroid-2-related factor-2 (Nrf2) and downregulation of mitochondrial manganese superoxide dismutase (SOD2) contributes to the establishment of chronic oxidative stress in aged vessels. This is accompanied by a chronic low-grade inflammatory phenotype that participates in defective endothelial vasodilation. The redox-sensitive transcription factor, nuclear factor-κB (NF-κB), is upregulated in vascular cells from old subjects and drives a proinflammatory shift that feedbacks oxidative stress. This chronic NF-κB activation is contributed by increased angiotensin-II signaling and downregulated sirtuins and precludes adequate cellular response to acute ROS generation. Interventions targeted to recover endogenous antioxidant capacity and cellular stress response rather than exogenous antioxidants could reverse oxidative stress-inflammation vicious cycle in vascular aging. Lifestyle attitudes such as caloric restriction and exercise training appear as effective ways to overcome defective antioxidant response and inflammation, favoring successful vascular aging and decreasing the risk for cardiovascular disease.
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Affiliation(s)
- Mariam El Assar
- Fundación para la Investigación Biomédica, Hospital Universitario de Getafe, Getafe, Spain
| | - Javier Angulo
- Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Leocadio Rodríguez-Mañas
- Fundación para la Investigación Biomédica, Hospital Universitario de Getafe, Getafe, Spain; Servicio de Geriatría, Hospital Universitario de Getafe, Getafe, Spain.
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Behringer EJ, Shaw RL, Westcott EB, Socha MJ, Segal SS. Aging impairs electrical conduction along endothelium of resistance arteries through enhanced Ca2+-activated K+ channel activation. Arterioscler Thromb Vasc Biol 2013; 33:1892-901. [PMID: 23723370 DOI: 10.1161/atvbaha.113.301514] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Intercellular conduction of electrical signals underlies spreading vasodilation of resistance arteries. Small- and intermediate-conductance Ca(2+)-activated K(+) channels of endothelial cells serve a dual function by initiating hyperpolarization and modulating electrical conduction. We tested the hypothesis that regulation of electrical signaling by small- and intermediate-conductance Ca(2+)-activated K(+) channels is altered with advancing age. APPROACH AND RESULTS Intact endothelial tubes (60 µm wide; 1-3 mm long) were freshly isolated from male C57BL/6 mouse (Young: 4-6 months; Intermediate: 12-14 months; Old: 24-26 months) superior epigastric arteries. Using dual intracellular microelectrodes, current was injected (± 0.1-3 nA) at site 1 while recording membrane potential (Vm) at site 2 (separation distance: 50-2000 µm). Across age groups, greatest differences were observed between Young and Old. Resting Vm in Old (-38 ± 1 mV) was more negative (P<0.05) than Young (-30 ± 1 mV). Maximal hyperpolarization to both direct (NS309) and indirect (acetylcholine) activation of small- and intermediate-conductance Ca(2+)-activated K(+) channels was sustained (ΔVm ≈-40 mV) with age. The length constant (λ) for electrical conduction was reduced (P<0.05) from 1630 ± 80 µm (Young) to 1320 ± 80 µm (Old). Inhibiting small- and intermediate-conductance Ca(2+)-activated K(+) channels with apamin+charybdotoxin or scavenging hydrogen peroxide (H2O2) with catalase improved electrical conduction (P<0.05) in Old. Exogenous H2O2 (200 µmol/L) in Young evoked hyperpolarization and impaired electrical conduction; these effects were blocked by apamin+charybdotoxin. CONCLUSIONS Enhanced current loss through Ca2+-activated K+ channel activation impairs electrical conduction along the endothelium of resistance arteries with aging. Attenuating the spatial domain of electrical signaling will restrict the spread of vasodilation and thereby contribute to blood flow limitations associated with advanced age.
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Affiliation(s)
- Erik J Behringer
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65212, USA
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