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Diaz M, Parikh V, Ismail S, Maxamed R, Tye E, Austin C, Dew T, Graf BA, Vanhees L, Degens H, Azzawi M. Differential effects of resveratrol on the dilator responses of femoral arteries, ex vivo. Nitric Oxide 2019; 92:1-10. [DOI: 10.1016/j.niox.2019.07.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 07/12/2019] [Accepted: 07/25/2019] [Indexed: 12/22/2022]
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Parikh V, Kadiwala J, Hidalgo Bastida A, Holt C, Sanami M, Miraftab M, Shakur R, Azzawi M. Small diameter helical vascular scaffolds support endothelial cell survival. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2018; 14:2598-2608. [PMID: 30172863 DOI: 10.1016/j.nano.2018.08.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 07/12/2018] [Accepted: 08/10/2018] [Indexed: 10/28/2022]
Abstract
There is an acute clinical need for small-diameter vascular grafts as a treatment option for cardiovascular disease. Here, we used an intelligent design system to recreate the natural structure and hemodynamics of small arteries. Nano-fibrous tubular scaffolds were fabricated from blends of polyvinyl alcohol and gelatin with inner helices to allow a near physiological spiral flow profile, using the electrospinning technique. Human coronary artery endothelial cells (ECs) were seeded on the inner surface and their viability, distribution, gene expression of mechanosensitive and adhesion molecules compared to that in conventional scaffolds, under static and flow conditions. We show significant improvement in cell distribution in helical vs. conventional scaffolds (94% ± 9% vs. 82% ± 7.2%; P < 0.05) with improved responsiveness to shear stress and better ability to withhold physiological pressures. Our helical vascular scaffold provides an improved niche for EC growth and may be attractive as a potential small diameter vascular graft.
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Affiliation(s)
- Vijay Parikh
- Cardiovascular Research Group, School of Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom; Institute for Materials Research and Innovation (IMRI), University of Bolton, Manchester, United Kingdom
| | - Juned Kadiwala
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, University of Cambridge, Cambridge, UK
| | - Araida Hidalgo Bastida
- Cardiovascular Research Group, School of Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom
| | - Cathy Holt
- Institute for Cardiovascular Science, University of Manchester, Manchester, UK
| | - Mohammad Sanami
- Institute for Materials Research and Innovation (IMRI), University of Bolton, Manchester, United Kingdom
| | - Mohsen Miraftab
- Institute for Materials Research and Innovation (IMRI), University of Bolton, Manchester, United Kingdom; Medical Device Consultants Limited, Wilmslow, UK
| | - Rameen Shakur
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, University of Cambridge, Cambridge, UK.
| | - May Azzawi
- Cardiovascular Research Group, School of Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom.
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Abstract
The heart is uniquely responsible for providing its own blood supply through the coronary circulation. Regulation of coronary blood flow is quite complex and, after over 100 years of dedicated research, is understood to be dictated through multiple mechanisms that include extravascular compressive forces (tissue pressure), coronary perfusion pressure, myogenic, local metabolic, endothelial as well as neural and hormonal influences. While each of these determinants can have profound influence over myocardial perfusion, largely through effects on end-effector ion channels, these mechanisms collectively modulate coronary vascular resistance and act to ensure that the myocardial requirements for oxygen and substrates are adequately provided by the coronary circulation. The purpose of this series of Comprehensive Physiology is to highlight current knowledge regarding the physiologic regulation of coronary blood flow, with emphasis on functional anatomy and the interplay between the physical and biological determinants of myocardial oxygen delivery. © 2017 American Physiological Society. Compr Physiol 7:321-382, 2017.
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Affiliation(s)
- Adam G Goodwill
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
| | - Gregory M Dick
- California Medical Innovations Institute, 872 Towne Center Drive, Pomona, CA
| | - Alexander M Kiel
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
- Weldon School of Biomedical Engineering, Purdue University, 206 S Martin Jischke Drive, Lafayette, IN
| | - Johnathan D Tune
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
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Ellinsworth DC, Sandow SL, Shukla N, Liu Y, Jeremy JY, Gutterman DD. Endothelium-Derived Hyperpolarization and Coronary Vasodilation: Diverse and Integrated Roles of Epoxyeicosatrienoic Acids, Hydrogen Peroxide, and Gap Junctions. Microcirculation 2016; 23:15-32. [PMID: 26541094 DOI: 10.1111/micc.12255] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 11/01/2015] [Indexed: 12/22/2022]
Abstract
Myocardial perfusion and coronary vascular resistance are regulated by signaling metabolites released from the local myocardium that act either directly on the VSMC or indirectly via stimulation of the endothelium. A prominent mechanism of vasodilation is EDH of the arteriolar smooth muscle, with EETs and H(2)O(2) playing important roles in EDH in the coronary microcirculation. In some cases, EETs and H(2)O(2) are released as transferable hyperpolarizing factors (EDHFs) that act directly on the VSMCs. By contrast, EETs and H(2)O(2) can also promote endothelial KCa activity secondary to the amplification of extracellular Ca(2+) influx and Ca(2+) mobilization from intracellular stores, respectively. The resulting endothelial hyperpolarization may subsequently conduct to the media via myoendothelial gap junctions or potentially lead to the release of a chemically distinct factor(s). Furthermore, in human isolated coronary arterioles dilator signaling involving EETs and H(2)O(2) may be integrated, being either complimentary or inhibitory depending on the stimulus. With an emphasis on the human coronary microcirculation, this review addresses the diverse and integrated mechanisms by which EETs and H(2)O(2) regulate vessel tone and also examines the hypothesis that myoendothelial microdomain signaling facilitates EDH activity in the human heart.
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Affiliation(s)
| | - Shaun L Sandow
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore, Queensland, Australia
| | - Nilima Shukla
- Bristol Heart Institute, University of Bristol, Bristol, UK
| | - Yanping Liu
- Division of Research Infrastructure, National Center for Research Resources, National Institutes of Health, Bethesda, Maryland, USA
| | - Jamie Y Jeremy
- Bristol Heart Institute, University of Bristol, Bristol, UK
| | - David D Gutterman
- Division of Cardiovascular Medicine, Departments of Medicine, Physiology and Pharmacology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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Heaps CL, Robles JC, Sarin V, Mattox ML, Parker JL. Exercise training-induced adaptations in mediators of sustained endothelium-dependent coronary artery relaxation in a porcine model of ischemic heart disease. Microcirculation 2015; 21:388-400. [PMID: 24447072 DOI: 10.1111/micc.12116] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 01/16/2014] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The aim of this study was to test the hypothesis that exercise training enhances sustained relaxation to persistent endothelium-dependent vasodilator exposure via increased nitric oxide contribution in small coronary arteries of control and ischemic hearts. METHODS Yucatan swine were designated to a control group or a group in which an ameroid constrictor was placed around the proximal LCX. Subsequently, pigs from both groups were assigned to exercise (five days/week; 16 weeks) or SED regimens. Coronary arteries (~100-350 μm) were isolated from control pigs and from both nonoccluded and collateral-dependent regions of chronically-occluded hearts. RESULTS In arteries from control pigs, training significantly enhanced relaxation responses to increasing concentrations of bradykinin (10(-10) -10(-7) M) and sustained relaxation to a single bradykinin concentration (30 nM), which were abolished by NOS inhibition. Training also significantly prolonged bradykinin-mediated relaxation in collateral-dependent arteries of occluded pigs, which was associated with more persistent increases in endothelial cellular Ca(2+) levels, and reversed with NOS inhibition. Protein levels for eNOS and p-eNOS-(Ser1179), but not caveolin-1, Hsp90, or Akt, were significantly increased with occlusion, independent of training state. CONCLUSIONS Exercise training enhances sustained relaxation to endothelium-dependent agonist stimulation in small arteries of control and ischemic hearts by enhanced nitric oxide contribution and endothelial Ca(2+) responses.
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Affiliation(s)
- Cristine L Heaps
- Michael E. DeBakey Institute for Comparative Cardiovascular Science and Biomedical Devices, Texas A&M University, College Station, Texas, USA; Department of Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
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Withers S, Taggart M, Austin C. Isolated small uterine arteries from non-pregnant and term pregnant rats exhibit regulatory responses to elevations in extravascular pressure. Placenta 2012. [PMID: 23195572 DOI: 10.1016/j.placenta.2012.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
An adequate blood supply is essential for the maintenance of uterine function and fetal health during parturition. However, labouring uterine contractions will impart compressive forces on small uterine arteries (SUA). We demonstrate that isolated, pressurised rat SUA arteries, pre-constricted with arginine vasopressin or high potassium solution, exhibit regulatory responses to elevations in extravascular pressure (EVP) which maintain internal diameter constant at EVPs of 0-40 mm Hg. This response is endothelium independent and is not modulated by pregnancy. No regulation was observed in calcium free solution. SUA myogenic responses to elevated EVP likely represents a mechanism for limiting reductions in uterine blood flow during uterine contraction.
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Affiliation(s)
- S Withers
- Cardiovascular Research Group, Core Technology Facility, University of Manchester, 46 Grafton Street, Manchester, UK
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Hypoxia in early pregnancy induces cardiac dysfunction in adult offspring of Rattus norvegicus, a non-hypoxia-adapted species. Comp Biochem Physiol A Mol Integr Physiol 2012; 163:278-85. [DOI: 10.1016/j.cbpa.2012.07.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 07/31/2012] [Accepted: 07/31/2012] [Indexed: 11/21/2022]
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Nakabayashi S, Nagaoka T, Tani T, Sogawa K, Hein TW, Kuo L, Yoshida A. Retinal arteriolar responses to acute severe elevation in systemic blood pressure in cats: role of endothelium-derived factors. Exp Eye Res 2012; 103:63-70. [PMID: 22940370 DOI: 10.1016/j.exer.2012.08.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 08/15/2012] [Accepted: 08/17/2012] [Indexed: 11/24/2022]
Abstract
The purpose of this study was to investigate the roles of endothelium-derived factors in the retinal arteriolar responses to acute severe elevation in systemic blood pressure (BP) in cats. Acute elevation of mean arterial BP by 60% for 5 min was achieved by inflating a balloon-tipped catheter in the descending aorta. The retinal arteriolar diameter, flow velocity, wall shear rate (WSR) and blood flow (RBF) changes during BP elevation were assessed with laser Doppler velocimetry 2 h after intravitreal injections of nitric oxide (NO) synthase inhibitor l-NAME, cyclooxygenase inhibitor indomethacin, endothelin-1 receptor antagonists (BQ-123 for type A and BQ-788 for type B), or Rho kinase inhibitor fasudil. BP elevation caused a marked increase in retinal arteriolar flow velocity and WSR with slight vasoconstriction, resulting in an increase in RBF. The increases in velocity, WSR and RBF, but not diameter, were correlated with the increase in ocular perfusion pressure. With l-NAME or indomethacin, the increase in RBF upon BP elevation was significantly attenuated due to enhanced retinal arteriolar vasoconstriction. In contrast, BQ-123 and fasudil potentiated the increased RBF. BQ-788 had no effect on arteriolar diameter and hemodynamics. Our data suggest that acute elevation of BP by 60% leads to an increase in RBF due to the release of NO and prostanoids probably through a shear stress-induced vasodilation mechanism. The release of endothelin-1 and Rho kinase activation help to limit RBF augmentation by counteracting the vasodilation. It appears that the retinal endothelium, by releasing vasoactive substances, contributes to RBF regulation during acute severe elevation of systemic blood pressure.
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Affiliation(s)
- Seigo Nakabayashi
- Department of Ophthalmology, Asahikawa Medical University, Midorigaoka Higashi 2-1-1-1, Asahikawa 078-8510, Japan
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Morton JS, Rueda-Clausen CF, Davidge ST. Flow-mediated vasodilation is impaired in adult rat offspring exposed to prenatal hypoxia. J Appl Physiol (1985) 2011; 110:1073-82. [DOI: 10.1152/japplphysiol.01174.2010] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
There is now a demonstrated association between low birth weight and increased mortality later in life. Changes in fetal development may program the cardiovascular system and lead to an increased risk of cardiovascular diseases later in life. In addition, aging is a risk factor for vascular endothelial-dependent dysfunction. However, the impact of being born intrauterine growth restricted (IUGR) on the normal aging mechanisms of vascular dysfunction is not clear. We hypothesized that IUGR would cause changes in vascular function that would affect the mechanisms of flow-induced vasodilation later in life in an age- or sex-dependent manner. To create an IUGR model, pregnant Sprague-Dawley rats were placed in a hypoxic (11.5% O2) or control (room air, 21% O2) environment from days 15 to 21 of pregnancy. Both male and female offspring were investigated at 4 or 12 mo of age. Vascular function was assessed in small mesenteric arteries using flow-induced vasodilation, a physiological stimuli of vasodilation, in a pressure myograph. Flow-induced vasodilation was unaffected at a young age, but was significantly reduced in aging IUGR compared with aging controls ( P < 0.05). Underlying vasodilator mechanisms were altered such that nitric oxide-mediated vasodilation was abolished in both young adult and aging IUGR males and females and in aging control females ( P > 0.05). Endothelium-derived hyperpolarizing factor-mediated vasodilation was maintained in all groups ( P < 0.01). A change in the mechanisms of vasodilation occurring at an earlier age in IUGR offspring may predispose them to develop cardiovascular diseases as an aging adult.
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Affiliation(s)
- J. S. Morton
- Departments of 1Obstetrics and Gynaecology and
- Women and Children's Health Research Institute and the Cardiovascular Research Centre, Edmonton, Alberta, Canada
| | - C. F. Rueda-Clausen
- Physiology, University of Alberta, and
- Women and Children's Health Research Institute and the Cardiovascular Research Centre, Edmonton, Alberta, Canada
| | - S. T. Davidge
- Departments of 1Obstetrics and Gynaecology and
- Physiology, University of Alberta, and
- Women and Children's Health Research Institute and the Cardiovascular Research Centre, Edmonton, Alberta, Canada
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Austin C. Commentaries on viewpoint: pick your Poiseuille: normalizing the shear stimulus in studies of flow-mediated dilation. J Appl Physiol (1985) 2009; 107:1365; author reply 1366. [PMID: 19847930 DOI: 10.1152/japplphysiol.00748.2009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Pyke KE, Hartnett JA, Tschakovsky ME. Are the dynamic response characteristics of brachial artery flow-mediated dilation sensitive to the magnitude of increase in shear stimulus? J Appl Physiol (1985) 2008; 105:282-92. [PMID: 18467554 DOI: 10.1152/japplphysiol.01190.2007] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose of this study was to determine the dynamic characteristics of brachial artery dilation in response to step increases in shear stress [flow-mediated dilation (FMD)]. Brachial artery diameter (BAD) and mean blood velocity (MBV) (Doppler ultrasound) were obtained in 15 healthy subjects. Step increases in MBV at two shear stimulus magnitudes were investigated: large (L; maximal MBV attainable), and small (S; MBV at 50% of the large step). Increase in shear rate (estimate of shear stress: MBV/BAD) was 76.8 +/- 15.6 s(-1) for L and 41.4 +/- 8.7 s(-1) for S. The peak %FMD was 14.5 +/- 3.8% for L and 5.7 +/- 2.1% for S (P < 0.001). Both the L (all subjects) and the S step trials (12 of 15 subjects) elicited a biphasic diameter response with a fast initial phase (phase I) followed by a slower final phase. Relative contribution of phase I to total FMD when two phases occurred was not sensitive to shear rate magnitude (r(2) = 0.003, slope P = 0.775). Parameters quantifying the dynamics of the FMD response [time delay (TD), time constant (tau)] were also not sensitive to shear rate magnitude for both phases (phase I: TD r(2) = 0.03, slope P = 0.376, tau r(2) = 0.04, slope P = 0.261; final phase: TD r(2) = 0.07, slope P = 0.169, tau r(2) = 0.07, slope P = 0.996). These data support the existence of two distinct mechanisms, or sets of mechanisms, in the human conduit artery FMD response that are proportionally sensitive to shear stimulus magnitude and whose dynamic response is not sensitive to shear stimulus magnitude.
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Affiliation(s)
- K E Pyke
- Queen's University, Kingston, Ontario, Canada
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