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Chlupac J, Frank J, Sedmera D, Fabian O, Simunkova Z, Mrazova I, Novak T, Vanourková Z, Benada O, Pulda Z, Adla T, Kveton M, Lodererova A, Voska L, Pirk J, Fronek J. External Support of Autologous Internal Jugular Vein Grafts with FRAME Mesh in a Porcine Carotid Artery Model. Biomedicines 2024; 12:1335. [PMID: 38927542 PMCID: PMC11201386 DOI: 10.3390/biomedicines12061335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 05/28/2024] [Accepted: 06/12/2024] [Indexed: 06/28/2024] Open
Abstract
BACKGROUND Autologous vein grafts are widely used for bypass procedures in cardiovascular surgery. However, these grafts are susceptible to failure due to vein graft disease. Our study aimed to evaluate the impact of the latest-generation FRAME external support on vein graft remodeling in a preclinical model. METHODS We performed autologous internal jugular vein interposition grafting in porcine carotid arteries for one month. Four grafts were supported with a FRAME mesh, while seven unsupported grafts served as controls. The conduits were examined through flowmetry, angiography, macroscopy, and microscopy. RESULTS The one-month patency rate of FRAME-supported grafts was 100% (4/4), whereas that of unsupported controls was 43% (3/7, Log-rank p = 0.071). On explant angiography, FRAME grafts exhibited significantly more areas with no or mild stenosis (9/12) compared to control grafts (3/21, p = 0.0009). Blood flow at explantation was higher in the FRAME grafts (145 ± 51 mL/min) than in the controls (46 ± 85 mL/min, p = 0.066). Area and thickness of neo-intimal hyperplasia (NIH) at proximal anastomoses were similar for the FRAME and the control groups: 5.79 ± 1.38 versus 6.94 ± 1.10 mm2, respectively (p = 0.558) and 480 ± 95 vs. 587 ± 52 μm2/μm, respectively (p = 0.401). However, in the midgraft portions, the NIH area and thickness were significantly lower in the FRAME group than in the control group: 3.73 ± 0.64 vs. 6.27 ± 0.64 mm2, respectively (p = 0.022) and 258 ± 49 vs. 518 ± 36 μm2/μm, respectively (p = 0.0002). CONCLUSIONS In our porcine model, the external mesh FRAME improved the patency of vein-to-carotid artery grafts and protected them from stenosis, particularly in the mid regions. The midgraft neo-intimal hyperplasia was two-fold thinner in the meshed grafts than in the controls.
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Affiliation(s)
- Jaroslav Chlupac
- Transplantation Surgery Department, Institute for Clinical and Experimental Medicine (IKEM), Videnska 1958/9, 140 21 Prague, Czech Republic; (J.F.); (T.N.); (J.F.)
- Department of Anatomy, Second Faculty of Medicine, Charles University, V Uvalu 84, 150 06 Prague, Czech Republic
| | - Jan Frank
- Transplantation Surgery Department, Institute for Clinical and Experimental Medicine (IKEM), Videnska 1958/9, 140 21 Prague, Czech Republic; (J.F.); (T.N.); (J.F.)
| | - David Sedmera
- Institute of Anatomy, First Faculty of Medicine, Charles University, U Nemocnice 3, Praha 2, 128 00 Prague, Czech Republic;
| | - Ondrej Fabian
- Clinical and Transplant Pathology Centre, Institute for Clinical and Experimental Medicine (IKEM), Videnska 1958/9, 140 21 Prague, Czech Republic; (O.F.); (M.K.); (A.L.); (L.V.)
- Department of Pathology and Molecular Medicine, Third Faculty of Medicine, Charles University, and Thomayer University Hospital, Ruska 87, 100 00 Prague, Czech Republic
| | - Zuzana Simunkova
- Experimental Medicine Centre, Institute for Clinical and Experimental Medicine (IKEM), Videnska 1958/9, 140 21 Prague, Czech Republic; (Z.S.); (I.M.); (Z.V.)
| | - Iveta Mrazova
- Experimental Medicine Centre, Institute for Clinical and Experimental Medicine (IKEM), Videnska 1958/9, 140 21 Prague, Czech Republic; (Z.S.); (I.M.); (Z.V.)
| | - Tomas Novak
- Transplantation Surgery Department, Institute for Clinical and Experimental Medicine (IKEM), Videnska 1958/9, 140 21 Prague, Czech Republic; (J.F.); (T.N.); (J.F.)
| | - Zdenka Vanourková
- Experimental Medicine Centre, Institute for Clinical and Experimental Medicine (IKEM), Videnska 1958/9, 140 21 Prague, Czech Republic; (Z.S.); (I.M.); (Z.V.)
| | - Oldrich Benada
- Laboratory of Molecular Structure Characterization, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 142 00 Prague, Czech Republic;
| | - Zdenek Pulda
- Department of Imaging Methods, Institute for Clinical and Experimental Medicine (IKEM), Videnska 1958/9, 140 21 Prague, Czech Republic; (Z.P.); (T.A.)
| | - Theodor Adla
- Department of Imaging Methods, Institute for Clinical and Experimental Medicine (IKEM), Videnska 1958/9, 140 21 Prague, Czech Republic; (Z.P.); (T.A.)
| | - Martin Kveton
- Clinical and Transplant Pathology Centre, Institute for Clinical and Experimental Medicine (IKEM), Videnska 1958/9, 140 21 Prague, Czech Republic; (O.F.); (M.K.); (A.L.); (L.V.)
- Third Faculty of Medicine, Charles University, Ruska 87, 100 00 Prague, Czech Republic
| | - Alena Lodererova
- Clinical and Transplant Pathology Centre, Institute for Clinical and Experimental Medicine (IKEM), Videnska 1958/9, 140 21 Prague, Czech Republic; (O.F.); (M.K.); (A.L.); (L.V.)
| | - Ludek Voska
- Clinical and Transplant Pathology Centre, Institute for Clinical and Experimental Medicine (IKEM), Videnska 1958/9, 140 21 Prague, Czech Republic; (O.F.); (M.K.); (A.L.); (L.V.)
| | - Jan Pirk
- Cardiovascular Surgery Department, Institute for Clinical and Experimental Medicine (IKEM), Videnska 1958/9, 140 21 Prague, Czech Republic;
| | - Jiri Fronek
- Transplantation Surgery Department, Institute for Clinical and Experimental Medicine (IKEM), Videnska 1958/9, 140 21 Prague, Czech Republic; (J.F.); (T.N.); (J.F.)
- Department of Anatomy, Second Faculty of Medicine, Charles University, V Uvalu 84, 150 06 Prague, Czech Republic
- First Surgical Clinic, First Faculty of Medicine, Charles University, U Nemocnice 499/2, 128 08 Prague, Czech Republic
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2
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Zhang D, Cao Y, Liu D, Zhang J, Guo Y. The Etiology and Molecular Mechanism Underlying Smooth Muscle Phenotype Switching in Intimal Hyperplasia of Vein Graft and the Regulatory Role of microRNAs. Front Cardiovasc Med 2022; 9:935054. [PMID: 35966541 PMCID: PMC9365958 DOI: 10.3389/fcvm.2022.935054] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/20/2022] [Indexed: 11/13/2022] Open
Abstract
Mounting evidence suggests that the phenotypic transformation of venous smooth muscle cells (SMCs) from differentiated (contractile) to dedifferentiated (proliferative and migratory) phenotypes causes excessive proliferation and further migration to the intima leading to intimal hyperplasia, which represents one of the key pathophysiological mechanisms of vein graft restenosis. In recent years, numerous miRNAs have been identified as specific phenotypic regulators of vascular SMCs (VSMCs), which play a vital role in intimal hyperplasia in vein grafts. The review sought to provide a comprehensive overview of the etiology of intimal hyperplasia, factors affecting the phenotypic transformation of VSMCs in vein graft, and molecular mechanisms of miRNAs involved in SMCs phenotypic modulation in intimal hyperplasia of vein graft reported in recent years.
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Affiliation(s)
- Dengshen Zhang
- Department of Cardiovascular Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Yiran Cao
- Department of Cardiovascular Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Daxing Liu
- Department of Cardiovascular Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Jian Zhang
- Department of Cardiovascular Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Yingqiang Guo
- Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, China
- *Correspondence: Yingqiang Guo,
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3
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Fashina O, Abbasciano RG, McQueen LW, Ladak S, George SJ, Suleiman S, Punjabi PP, Angelini GD, Zakkar M. Large animal model of vein grafts intimal hyperplasia: A systematic review. Perfusion 2022:2676591221091200. [PMID: 35624557 DOI: 10.1177/02676591221091200] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Coronary artery bypass grafting remains the treatment of choice for a large cohort of patients with significant coronary disease. Despite the increased use of arterial grafts, the long saphenous vein remains the most commonly used conduit. Long-term graft patency continues to be the Achilles heel of saphenous vein grafts. This is due to the development of intimal hyperplasia, a chronic inflammatory disease that results in the narrowing and occlusion of a significant number of vein grafts. Research models for intimal hyperplasia are essential for a better understanding of pathophysiological processes of this condition. Large animal models resemble human anatomical structures and have been used as a surrogate to study disease development and prevention over the years. In this paper, we systematically review all published studies that utilized large animal models of vein graft disease with a focus on the type of model and any therapeutic intervention, specifically the use of external stents/mesh.
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Affiliation(s)
- Oluwatomini Fashina
- Department of Cardiovascular Sciences, University of Leicester, Glenfield Hospital, Leicester, UK
| | - Riccardo G Abbasciano
- Department of Cardiovascular Sciences, University of Leicester, Glenfield Hospital, Leicester, UK
| | - Liam W McQueen
- Department of Cardiovascular Sciences, University of Leicester, Glenfield Hospital, Leicester, UK
| | - Shameem Ladak
- Department of Cardiovascular Sciences, University of Leicester, Glenfield Hospital, Leicester, UK
| | - Sarah J George
- Bristol Heart Institute and Translational Biomedical Research Centre, Bristol Medical School, University of Bristol, Bristol Royal Infirmary, Bristol, UK
| | - Sadeeh Suleiman
- Bristol Heart Institute and Translational Biomedical Research Centre, Bristol Medical School, University of Bristol, Bristol Royal Infirmary, Bristol, UK
| | - Prakash P Punjabi
- Department of Cardiovascular Sciences, Imperial College, Hammersmith Hospital, London, UK
| | - Gianni D Angelini
- Bristol Heart Institute and Translational Biomedical Research Centre, Bristol Medical School, University of Bristol, Bristol Royal Infirmary, Bristol, UK
| | - Mustafa Zakkar
- Department of Cardiovascular Sciences, University of Leicester, Glenfield Hospital, Leicester, UK
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4
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Goldstein DJ. Device Profile of the VEST for External Support of SVG Coronary Artery Bypass Grafting: Historical Development, Current Status and Future Directions. Expert Rev Med Devices 2021; 18:921-931. [PMID: 34311644 DOI: 10.1080/17434440.2021.1960504] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
A search for strategies to address saphenous vein graft (SVG) failure - the main factor limiting the long-term success of coronary bypass grafting - has led to trialing of external stenting technologies. AREAS COVERED The manuscript covers historical development and current status of external scaffolding for the treatment of SVG intimal hyperplasia. Comprehensive literature review and personal communication with VGS leadership, the developer of the VEST device, served as the sources. EXPERT OPINION If the external scaffolding concept proves to be successful in mitigating the intimal hyperplasia inherent to arterialized saphenous vein conduits, it could have a dramatic impact on the recurrence of anginal symptoms, the need for repeat revascularization, and the incidence of myocardial infarction following CABG surgery. These laudable sequelae could ultimately convey significant public health repercussions by reducing healthcare resource use and improving the long-term survival and quality of life of CABG recipients.
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Affiliation(s)
- Daniel J Goldstein
- Montefiore Medical Center - Cardiothoracic Surgery, Bainbridge Ave MAP Building, 5th Fl Bronx, New York, USA
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5
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Zhang Y, Fang Q, Niu K, Gan Z, Yu Q, Gu T. Time-dependently slow-released multiple-drug eluting external sheath for efficient long-term inhibition of saphenous vein graft failure. J Control Release 2019; 293:172-182. [DOI: 10.1016/j.jconrel.2018.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 11/19/2018] [Accepted: 12/01/2018] [Indexed: 12/22/2022]
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6
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Tianshu-Chu, Congrong-Gao, Zhiwei-Zhao, Fei-Ling, Ayu-Sun, Yuanbiao-Zheng, Jing-Cao, Ge J. Rapamycin Combined with α-Cyanoacrylate Contributes to Inhibiting Intimal Hyperplasia in Rat Models. Arq Bras Cardiol 2018; 112:3-10. [PMID: 30570064 PMCID: PMC6317635 DOI: 10.5935/abc.20180247] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 07/23/2018] [Indexed: 11/30/2022] Open
Abstract
Background Vein graft restenosis has an adverse impact on bridge vessel circulation and
patient prognosis after coronary artery bypass grafting. Objectives We used the extravascular supporter α-cyanoacrylate (α-CA), the
local application rapamycin/sirolimus (RPM), and a combination of the two
(α-CA-RPM) in rat models of autogenous vein graft to stimulate vein
graft change. The aim of our study was to observe the effect of α-CA,
RPM, and α-CA-RPM on vein hyperplasia. Methods Fifty healthy Sprague Dawley (SD) rats were randomized into the following 5
groups: sham, control, α-CA, RPM, and α-CA-RPM. Operating
procedure as subsequently described was used to build models of grafted rat
jugular vein on carotid artery on one side. The level of endothelin-1 (ET-1)
was determined by enzyme-linked immunosorbent assay (ELISA). Grafted veins
were observed via naked eye 4 weeks later; fresh veins were observed via
microscope and image-processing software in hematoxylin-eosin (HE) staining
and immunohistochemistry after having been fixed and stored” (i.e. First
they were fixed and stored, and second they were observed); α-Smooth
Muscle Actin (αSMA) and von Willebrand factor (vWF) were measured
with reverse transcription-polymerase chain reaction (RT-PCR). Comparisons
were made with single-factor analysis of variance and Fisher’s least
significant difference test, with p < 0.05 considered significant. Results We found that intimal thickness of the α-CA, RPM, and α-CA-RPM
groups was lower than that of the control group (p < 0.01), and the
thickness of the α-CA-RPM group was notably lower than that of the
α-CA and RPM groups (p < 0.05). Conclusion RPM combined with α-CA contributes to inhibiting intimal hyperplasia
in rat models and is more effective for vascular patency than individual use
of either α-CA or RPM.
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Affiliation(s)
| | | | | | - Fei-Ling
- Anhui Medical University, Hefei - China
| | - Ayu-Sun
- Anhui Medical University, Hefei - China
| | | | - Jing-Cao
- Anhui Medical University, Hefei - China
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7
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Loesch A, Dashwood MR. Vasa vasorum inside out/outside in communication: a potential role in the patency of saphenous vein coronary artery bypass grafts. J Cell Commun Signal 2018; 12:631-643. [PMID: 30078142 PMCID: PMC6235771 DOI: 10.1007/s12079-018-0483-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Accepted: 07/30/2018] [Indexed: 01/08/2023] Open
Abstract
The saphenous vein (SV) is the most commonly used conduit for revascularization in patients undergoing coronary artery bypass surgery (CABG). The patency rate of this vessel is inferior to the internal thoracic artery (ITA). In the majority of CABG procedures the ITA is removed with its outer pedicle intact whereas the (human) SV (hSV) is harvested with pedicle removed. The vasa vasorum, a microvessel network providing the adventitia and media with oxygen and nutrients, is more pronounced and penetrates deeper towards the lumen in veins than in arteries. When prepared in conventional CABG the vascular trauma caused when removing the hSV pedicle damages the vasa vasorum, a situation affecting transmural flow potentially impacting on graft performance. In patients, where the hSV is harvested with pedicle intact, the vasa vasorum is preserved and transmural blood flow restored at graft insertion and completion of CABG. By maintaining blood supply to the hSV wall, apart from oxygen and nutrients, the vasa vasorum may also transport factors potentially beneficial to graft performance. Studies, using either corrosion casts or India ink, have shown the course of vasa vasorum in animal SV as well as in hSV. In addition, there is some evidence that vasa vasorum of hSV terminate in the vessel lumen based on ex vivo perfusion, histological and ultrastructural studies. This review describes the preparation of the hSV as a bypass conduit in CABG and its performance compared with the ITA as well as how and why its patency might be improved by harvesting with minimal trauma in a way that preserves an intact vasa vasorum.
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Affiliation(s)
- Andrzej Loesch
- Centre for Rheumatology and Connective Tissue Diseases, Division of Medicine, University College London Medical School, Royal Free Campus, Rowland Hill Street, London, NW3 2PF, UK.
| | - Michael R Dashwood
- Division of Surgery and Interventional Science, Faculty of Medical Sciences, University College London Medical School, Royal Free Campus, Rowland Hill Street, London, NW3 2PF, UK.
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8
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Hudson C, Kimura TE, Duggirala A, Sala-Newby GB, Newby AC, Bond M. Dual Role of CREB in The Regulation of VSMC Proliferation: Mode of Activation Determines Pro- or Anti-Mitogenic Function. Sci Rep 2018; 8:4904. [PMID: 29559698 PMCID: PMC5861041 DOI: 10.1038/s41598-018-23199-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 03/06/2018] [Indexed: 11/15/2022] Open
Abstract
Vascular smooth muscle cell (VSMC) proliferation has been implicated in the development of restenosis after angioplasty, vein graft intimal thickening and atherogenesis. We investigated the mechanisms underlying positive and negative regulation of VSMC proliferation by the transcription factor cyclic AMP response element binding protein (CREB). Incubation with the cAMP elevating stimuli, adenosine, prostacyclin mimetics or low levels of forksolin activated CREB without changing CREB phosphorylation on serine-133 but induced nuclear translocation of the CREB co-factors CRTC-2 and CRTC-3. Overexpression of CRTC-2 or -3 significantly increased CREB activity and inhibited VSMC proliferation, whereas CRTC-2/3 silencing inhibited CREB activity and reversed the anti-mitogenic effects of adenosine A2B receptor agonists. By contrast, stimulation with serum or PDGFBB significantly increased CREB activity, dependent on increased CREB phosphorylation at serine-133 but not on CRTC-2/3 activation. CREB silencing significantly inhibited basal and PDGF induced proliferation. These data demonstrate that cAMP activation of CREB, which is CRTC2/3 dependent and serine-133 independent, is anti-mitogenic. Growth factor activation of CREB, which is serine-133-dependent and CRTC2/3 independent, is pro-mitogenic. Hence, CREB plays a dual role in the regulation of VSMC proliferation with the mode of activation determining its pro- or anti-mitogenic function.
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Affiliation(s)
- Claire Hudson
- Translational Health Sciences, University of Bristol, Research Floor Level 7, Bristol Royal Infirmary, Bristol, BS2 8HW, UK
| | - Tomomi E Kimura
- Translational Health Sciences, University of Bristol, Research Floor Level 7, Bristol Royal Infirmary, Bristol, BS2 8HW, UK.,School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Aparna Duggirala
- Translational Health Sciences, University of Bristol, Research Floor Level 7, Bristol Royal Infirmary, Bristol, BS2 8HW, UK
| | - Graciela B Sala-Newby
- Translational Health Sciences, University of Bristol, Research Floor Level 7, Bristol Royal Infirmary, Bristol, BS2 8HW, UK
| | - Andrew C Newby
- Translational Health Sciences, University of Bristol, Research Floor Level 7, Bristol Royal Infirmary, Bristol, BS2 8HW, UK
| | - Mark Bond
- Translational Health Sciences, University of Bristol, Research Floor Level 7, Bristol Royal Infirmary, Bristol, BS2 8HW, UK.
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9
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Mawhinney JA, Mounsey CA, Taggart DP. The potential role of external venous supports in coronary artery bypass graft surgery†. Eur J Cardiothorac Surg 2017; 53:1127-1134. [DOI: 10.1093/ejcts/ezx432] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Accepted: 11/07/2017] [Indexed: 11/12/2022] Open
Affiliation(s)
| | | | - David P Taggart
- Department of Cardiothoracic Surgery, Oxford University Hospitals NHS Trust, Oxford, UK
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10
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Washington KS, Bashur CA. Delivery of Antioxidant and Anti-inflammatory Agents for Tissue Engineered Vascular Grafts. Front Pharmacol 2017; 8:659. [PMID: 29033836 PMCID: PMC5627016 DOI: 10.3389/fphar.2017.00659] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 09/05/2017] [Indexed: 01/21/2023] Open
Abstract
The treatment of patients with severe coronary and peripheral artery disease represents a significant clinical need, especially for those patients that require a bypass graft and do not have viable veins for autologous grafting. Tissue engineering is being investigated to generate an alternative graft. While tissue engineering requires surgical intervention, the release of pharmacological agents is also an important part of many tissue engineering strategies. Delivery of these agents offers the potential to overcome the major concerns for graft patency and viability. These concerns are related to an extended inflammatory response and its impact on vascular cells such as endothelial cells. This review discusses the drugs that have been released from vascular tissue engineering scaffolds and some of the non-traditional ways that the drugs are presented to the cells. The impact of antioxidant compounds and gasotransmitters, such as nitric oxide and carbon monoxide, are discussed in detail. The application of tissue engineering and drug delivery principles to biodegradable stents is also briefly discussed. Overall, there are scaffold-based drug delivery techniques that have shown promise for vascular tissue engineering, but much of this work is in the early stages and there are still opportunities to incorporate additional drugs to modulate the inflammatory process.
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Affiliation(s)
| | - Chris A. Bashur
- Department of Biomedical Engineering, Florida Institute of Technology, MelbourneFL, United States
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11
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Divergent Regulation of Actin Dynamics and Megakaryoblastic Leukemia-1 and -2 (Mkl1/2) by cAMP in Endothelial and Smooth Muscle Cells. Sci Rep 2017. [PMID: 28623279 PMCID: PMC5473867 DOI: 10.1038/s41598-017-03337-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Proliferation and migration of vascular smooth muscle cells (VSMCs) or endothelial cell (ECs) promote or inhibit, respectively, restenosis after angioplasty, vein graft intimal thickening and atherogenesis. Here we investigated the effects of cAMP-induced cytoskeletal remodelling on the serum response factor (SRF) co-factors Megakaryoblastic Leukemia-1 and -2 (MKL1 and MKL2) and their role in controlling VSMC and EC proliferation and migration. Elevation of cAMP using forskolin, dibutyryl-cAMP (db-cAMP), BAY60-6583 or Cicaprost induced rapid cytoskeleton remodelling and inhibited proliferation and migration in VSMCs but not EC. Furthermore, elevated cAMP inhibited mitogen-induced nuclear-translocation of MKL1 and MKL2 in VSMCs but not ECs. Forskolin also significantly inhibited serum response factor (SRF)-dependent reporter gene (SRE-LUC) activity and mRNA expression of pro-proliferative and pro-migratory MKL1/2 target genes in VSMCs but not in ECs. In ECs, MKL1 was constitutively nuclear and MKL2 cytoplasmic, irrespective of mitogens or cAMP. Pharmacological or siRNA inhibition of MKL1 significantly inhibited the proliferation and migration of VSMC and EC. Our new data identifies and important contribution of MKL1/2 to explaining the strikingly different response of VSMCs and ECs to cAMP elevation. Elucidation of these pathways promises to identify targets for specific inhibition of VSMC migration and proliferation.
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12
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Kimura TE, Duggirala A, Smith MC, White S, Sala-Newby GB, Newby AC, Bond M. The Hippo pathway mediates inhibition of vascular smooth muscle cell proliferation by cAMP. J Mol Cell Cardiol 2016; 90:1-10. [PMID: 26625714 PMCID: PMC4727789 DOI: 10.1016/j.yjmcc.2015.11.024] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 11/05/2015] [Accepted: 11/20/2015] [Indexed: 12/30/2022]
Abstract
AIMS Inhibition of vascular smooth muscle cell (VSMC) proliferation by intracellular cAMP prevents excessive neointima formation and hence angioplasty restenosis and vein-graft failure. These protective effects are mediated via actin-cytoskeleton remodelling and subsequent regulation of gene expression by mechanisms that are incompletely understood. Here we investigated the role of components of the growth-regulatory Hippo pathway, specifically the transcription factor TEAD and its co-factors YAP and TAZ in VSMC. METHODS AND RESULTS Elevation of cAMP using forskolin, dibutyryl-cAMP or the physiological agonists, Cicaprost or adenosine, significantly increased phosphorylation and nuclear export YAP and TAZ and inhibited TEAD-luciferase report gene activity. Similar effects were obtained by inhibiting RhoA activity with C3-transferase, its downstream kinase, ROCK, with Y27632, or actin-polymerisation with Latrunculin-B. Conversely, expression of constitutively-active RhoA reversed the inhibitory effects of forskolin on TEAD-luciferase. Forskolin significantly inhibited the mRNA expression of the pro-mitogenic genes, CCN1, CTGF, c-MYC and TGFB2 and this was reversed by expression of constitutively-active YAP or TAZ phospho-mutants. Inhibition of YAP and TAZ function with RNAi or Verteporfin significantly reduced VSMC proliferation. Furthermore, the anti-mitogenic effects of forskolin were reversed by overexpression of constitutively-active YAP or TAZ. CONCLUSION Taken together, these data demonstrate that cAMP-induced actin-cytoskeleton remodelling inhibits YAP/TAZ-TEAD dependent expression of pro-mitogenic genes in VSMC. This mechanism contributes novel insight into the anti-mitogenic effects of cAMP in VSMC and suggests a new target for intervention.
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Affiliation(s)
- Tomomi E Kimura
- Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol BS2 8HW, UK
| | - Aparna Duggirala
- Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol BS2 8HW, UK
| | - Madeleine C Smith
- Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol BS2 8HW, UK
| | - Stephen White
- Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol BS2 8HW, UK
| | - Graciela B Sala-Newby
- Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol BS2 8HW, UK
| | - Andrew C Newby
- Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol BS2 8HW, UK
| | - Mark Bond
- Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol BS2 8HW, UK.
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13
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Duggirala A, Kimura TE, Sala-Newby GB, Johnson JL, Wu YJ, Newby AC, Bond M. cAMP-induced actin cytoskeleton remodelling inhibits MKL1-dependent expression of the chemotactic and pro-proliferative factor, CCN1. J Mol Cell Cardiol 2015; 79:157-68. [PMID: 25446180 PMCID: PMC4312355 DOI: 10.1016/j.yjmcc.2014.11.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 10/24/2014] [Accepted: 11/12/2014] [Indexed: 12/17/2022]
Abstract
Elevation of intracellular cAMP concentration has numerous vascular protective effects that are in part mediated via actin cytoskeleton-remodelling and subsequent regulation of gene expression. However, the mechanisms are incompletely understood. Here we investigated whether cAMP-induced actin-cytoskeleton remodelling modulates VSMC behaviour by inhibiting expression of CCN1. In cultured rat VSMC, CCN1-silencing significantly inhibited BrdU incorporation and migration in a wound healing assay. Recombinant CCN1 enhanced chemotaxis in a Boyden chamber. Adding db-cAMP, or elevating cAMP using forskolin, significantly inhibited CCN1 mRNA and protein expression in vitro; transcriptional regulation was demonstrated by measuring pre-spliced CCN1 mRNA and CCN1-promoter activity. Forskolin also inhibited CCN1 expression in balloon injured rat carotid arteries in vivo. Inhibiting RhoA activity, which regulates actin-polymerisation, by cAMP-elevation or pharmacologically with C3-transferase, or inhibiting its downstream kinase, ROCK, with Y27632, significantly inhibited CCN1 expression. Conversely, expression of constitutively active RhoA reversed the inhibitory effects of forskolin on CCN1 mRNA. Furthermore, CCN1 mRNA levels were significantly decreased by inhibiting actin-polymerisation with latrunculin B or increased by stimulating actin-polymerisation with Jasplakinolide. We next tested the role of the actin-dependent SRF co-factor, MKL1, in CCN1 expression. Forskolin inhibited nuclear translocation of MKL1 and binding of MKL1 to the CCN1 promoter. Constitutively-active MKL1 enhanced basal promoter activity of wild-type but not SRE-mutated CCN1; and prevented forskolin inhibition. Furthermore, pharmacological MKL-inhibition with CCG-1423 significantly inhibited CCN1 promoter activity as well as mRNA and protein expression. Our data demonstrates that cAMP-induced actin-cytoskeleton remodelling regulates expression of CCN1 through MKL1: it highlights a novel cAMP-dependent mechanism controlling VSMC behaviour.
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Affiliation(s)
- Aparna Duggirala
- Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol, BS2 8HW, UK
| | - Tomomi E Kimura
- Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol, BS2 8HW, UK
| | - Graciela B Sala-Newby
- Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol, BS2 8HW, UK
| | - Jason L Johnson
- Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol, BS2 8HW, UK
| | - Yih-Jer Wu
- Department of Medicine, MacKay Medical College, New Taipei, Taiwan; Cardiovascular Division, Department of Internal Medicine, MacKay Memorial Hospital, New Taipei, Taiwan
| | - Andrew C Newby
- Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol, BS2 8HW, UK
| | - Mark Bond
- Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol, BS2 8HW, UK.
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14
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Abstract
Saphenous vein remains a widely used conduit in coronary surgery. However, the long-term success of surgical myocardial revascularization is largely limited by the development of neointimal hyperplasia and superimposed atherosclerosis in vein grafts. Although strategies for preventing vein graft failure have been constantly explored, few therapeutic interventions to date have shown sustained benefits in the clinical setting. The application of external support has emerged as a promising strategy for modulating the overall biomechanical responses in venous wall. Nonetheless, clinical translation of this intervention has been formerly challenged, primarily due to several technique limitations. The purpose of the current review is to summarize the possible mechanisms involved in the external support strategy for preventing vein graft failure. Furthermore, several previously tested biomaterials and delivery techniques are also highlighted.
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Affiliation(s)
- Jia Hu
- Division of Cardiothoracic Surgery, Department of Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, People's Republic of China
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15
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Dreifaldt M, Souza D, Bodin L, Shi-Wen X, Dooley A, Muddle J, Loesch A, Dashwood MR. The vasa vasorum and associated endothelial nitric oxide synthase is more important for saphenous vein than arterial bypass grafts. Angiology 2012; 64:293-9. [PMID: 22569406 DOI: 10.1177/0003319712443729] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
No-touch (NT) saphenous vein (SV) grafts are superior to SVs harvested by the conventional technique (CT), with a patency comparable with the internal thoracic artery (ITA). Preservation of the vasa vasorum is implicated in the success of NT harvesting. We compared the vasa vasorum and endothelial nitric oxide synthase (eNOS) in NT SV with ITA and radial artery (RA) grafts. Skeletonized SV (SSV) was also analyzed. The NT SV had a higher number and larger vasa vasorum compared with ITA (P = .0001) and RA (P = .0004) that correlated with eNOS protein. Activity of eNOS in SSV grafts was significantly lower than NT SV grafts (P = 004). Since a high proportion of the vasa vasorum are removed in SSV using the CT, we suggest that preservation of the vasa vasorum and eNOS-derived NO contributes to the high patency for NT as compared with SSV grafts.
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Affiliation(s)
- Mats Dreifaldt
- Department of Thoracic and Cardiovascular Surgery, Örebro University Hospital, Sweden
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16
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Shukla N, Jeremy JY. Pathophysiology of saphenous vein graft failure: a brief overview of interventions. Curr Opin Pharmacol 2012; 12:114-20. [PMID: 22321569 DOI: 10.1016/j.coph.2012.01.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 01/05/2012] [Accepted: 01/06/2012] [Indexed: 12/01/2022]
Abstract
Coronary artery bypass graft surgery (CABG) is widely used for the treatment of atheromatous stenosis of coronary arteries. However, as many as 50% of grafts fail within 10 years after CABG due to neointima (NI) formation, a process involving the proliferation of vascular smooth muscle cells (VSMCs) and superimposed atherogenesis. To date no therapeutic intervention has proved successful in treating late vein graft failure. However, several diverse approaches aimed at preventing neointimal formation have been devised which have yielded promising results. In this review, therefore, we will summarise the pathophysiology of vein graft disease and then briefly consider interventional approaches to prevent late vein graft failure which include surgical technique, conventional pharmacology, external sheaths, cytostatic drugs and gene transfer.
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Affiliation(s)
- Nilima Shukla
- Bristol Heart Institute, The University of Bristol, UK.
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17
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Vasorelaxation Effect and Mechanism of Action of Vascular Endothelial Growth Factor-165 in Isolated Perfused Human Skin Flaps. J Surg Res 2012; 172:177-86. [DOI: 10.1016/j.jss.2010.08.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 07/06/2010] [Accepted: 08/10/2010] [Indexed: 11/22/2022]
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18
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Endothelin-1 (ET-1) and vein graft failure and the therapeutic potential of ET-1 receptor antagonists. Pharmacol Res 2011; 63:483-9. [DOI: 10.1016/j.phrs.2010.10.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 10/27/2010] [Accepted: 10/29/2010] [Indexed: 12/21/2022]
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19
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Steinbicker AU, Liu H, Jiramongkolchai K, Malhotra R, Choe EY, Busch CJ, Graveline AR, Kao SM, Nagasaka Y, Ichinose F, Buys ES, Brouckaert P, Zapol WM, Bloch KD. Nitric oxide regulates pulmonary vascular smooth muscle cell expression of the inducible cAMP early repressor gene. Nitric Oxide 2011; 25:294-302. [PMID: 21642009 DOI: 10.1016/j.niox.2011.05.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 05/10/2011] [Accepted: 05/21/2011] [Indexed: 10/25/2022]
Abstract
Nitric oxide (NO) regulates vascular smooth muscle cell (VSMC) structure and function, in part by activating soluble guanylate cyclase (sGC) to synthesize cGMP. The objective of this study was to further characterize the signaling mechanisms by which NO regulates VSMC gene expression using transcription profiling. DNA microarrays were hybridized with RNA extracted from rat pulmonary artery smooth muscle cells (RPaSMC) exposed to the NO donor compound, S-nitroso-glutathione (GSNO). Many of the genes, whose expression was induced by GSNO, contain a cAMP-response element (CRE), of which one encoded the inducible cAMP early repressor (ICER). sGC and cAMP-dependent protein kinase, but not cGMP-dependent protein kinase, were required for NO-mediated phosphorylation of CRE-binding protein (CREB) and induction of ICER gene expression. Expression of a dominant-negative CREB in RPaSMC prevented the NO-mediated induction of CRE-dependent gene transcription and ICER gene expression. Pre-treatment of RPaSMC with the intracellular calcium (Ca(2+)) chelator, BAPTA-AM, blocked the induction of ICER gene expression by GSNO. The store-operated Ca(2+) channel inhibitors, 2-ABP, and SKF-96365, reduced the GSNO-mediated increase in ICER mRNA levels, while 2-ABP did not inhibit GSNO-induced CREB phosphorylation. Our results suggest that induction of ICER gene expression by NO requires both CREB phosphorylation and Ca(2+) signaling. Transcription profiling of RPaSMC exposed to GSNO revealed important roles for sGC, PKA, CREB, and Ca(2+) in the regulation of gene expression by NO. The induction of ICER in GSNO-treated RPaSMC highlights a novel cross-talk mechanism between cGMP and cAMP signaling pathways.
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Affiliation(s)
- Andrea U Steinbicker
- Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care and Pain Medicine, 55 Fruit Street, Boston, MA 02114, USA.
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20
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Dashwood MR, Savage K, Tsui JCS, Dooley A, Shaw SG, Fernández Alfonso MS, Bodin L, Souza DSR. Retaining perivascular tissue of human saphenous vein grafts protects against surgical and distension-induced damage and preserves endothelial nitric oxide synthase and nitric oxide synthase activity. J Thorac Cardiovasc Surg 2009; 138:334-40. [PMID: 19619776 DOI: 10.1016/j.jtcvs.2008.11.060] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 10/29/2008] [Accepted: 11/19/2008] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Conventional harvesting of saphenous vein used for coronary artery bypass surgery induces a vasospasm that is overcome by high-pressure distension. Saphenous vein harvested with its cushion of perivascular tissue by a "no touch" technique does not undergo vasospasm and distension is not required, leading to an improved graft patency. The aim of this study is to investigate the effect of surgical damage and high-pressure distension on endothelial integrity and endothelial nitric oxide synthase expression and activity in saphenous vein harvested with and without perivascular tissue. METHODS Saphenous veins from patients (n = 26) undergoing coronary artery bypass surgery were prepared with and without perivascular tissue. We analyzed the effect of 300 mm Hg distension on morphology and endothelial nitric oxide synthase/nitric oxide synthase activity using a combination of immunohistochemistry, Western blot analysis, reverse transcriptase polymerase chain reaction, and enzyme assay in distended (with and without perivascular tissue) compared with nondistended (with and without perivascular tissue) segments. RESULTS Distension induced substantial damage to the luminal endothelium (assessed by CD31 staining) and vessel wall. Endothelial nitric oxide synthase expression and activity were significantly reduced by high-pressure distension and removal of, or damage to, perivascular tissue. The effect of distension was significantly less for those with perivascular tissue than for those without perivascular tissue in most cases. CONCLUSION The success of the saphenous vein used as a bypass graft is affected by surgical trauma and distension. Veins removed with minimal damage exhibit increased patency rates. We show that retention of perivascular tissue on saphenous vein prepared for coronary artery bypass surgery by the "no touch" technique protects against distension-induced damage, preserves vessel morphology, and maintains endothelial nitric oxide synthase/nitric oxide synthase activity.
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Affiliation(s)
- Michael R Dashwood
- Department of Clinical Biochemistry, Royal Free and University College Medical School, Royal Free Campus, Pond Street, London, United Kingdom.
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21
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Human P, Franz T, Scherman J, Moodley L, Zilla P. Dimensional analysis of human saphenous vein grafts: Implications for external mesh support. J Thorac Cardiovasc Surg 2009; 137:1101-8. [PMID: 19379974 DOI: 10.1016/j.jtcvs.2008.10.040] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Revised: 09/05/2008] [Accepted: 10/03/2008] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Constrictive external mesh support of vein grafts was shown to mitigate intimal hyperplasia in animal experiments. To determine the degree of constriction required for the elimination of dimensional irregularities in clinically used vein grafts, a detailed anatomic study of human saphenous veins was conducted. METHODS In 200 consecutive patients having coronary artery bypass grafting, harvested saphenous veins (length 34.4 +/- 10.8 cm) were analyzed regarding diameter irregularities, side branch distribution, and microstructure. RESULTS The mean outer diameter of surgically distended saphenous veins was 4.2 +/- 0.6 mm (men, 4.3 +/- 0.6 mm vs women, 3.9 +/- 0.5 mm; P < .0001). Although the outer diameter significantly decreased over the initial 18 cm (-7.6%; P < .0001), the overall increase between malleolus and thigh was not significant (+11.2%). Smaller-diameter veins (<3.5 mm) had more pronounced diameter fluctuations than larger veins (31.8% +/- 11.0% vs 21.2% +/- 8.8%; P < .0001), with more than 71% of all veins showing caliber changes of more than 20%. There was 1 side branch every 5.4 +/- 4.3 cm, with a significantly higher incidence between 20 and 32 cm from the malleolus (P < .0001 to distal, P < .0004 to proximal). Generally, women had more side branches than men (0.30 +/- 0.15 cm(-1) vs 0.25 +/- 0.12 cm(-1); P = .0190). Thick-walled veins (565.7 +/- 138.4 mum) had a significantly higher number of large side branches (P < .0001), and thin-walled veins (398.7 +/- 123.2 mum) had significantly more small side branches (P < .0001). Pronounced intimal thickening ("cushions") was found in 28% of vessels (119.8 +/- 28.0 mum vs 40.1 +/- 18.2 mum; P < .0001). CONCLUSION Although the preferential location of side branches may be addressed by the deliberate discarding of infragenicular vein segments, a diameter constriction of 27% on average would eliminate diameter irregularities in 98% of vein grafts.
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Affiliation(s)
- Paul Human
- Christiaan Barnard Department of Cardiothoracic Surgery, University of Cape Town, Observatory, South Africa
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22
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Abstract
Endothelial cells, which form the inner cellular lining of blood vessels and lymphatics, display remarkable heterogeneity in structure and function. This is the second of a 2-part review on the phenotypic heterogeneity of blood vessel endothelial cells. The first part discusses the scope, the underlying mechanisms, and the diagnostic and therapeutic implications of phenotypic heterogeneity. Here, these principles are applied to an understanding of organ-specific phenotypes in representative vascular beds including arteries and veins, heart, lung, liver, and kidney. The goal is to underscore the importance of site-specific properties of the endothelium in mediating homeostasis and focal vascular pathology, while at the same time emphasizing the value of approaching the endothelium as an integrated system.
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Affiliation(s)
- William C Aird
- Division of Molecular and Vascular Medicine, Department of Medicine, and Center for Vascular Biology Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass 02215, USA.
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23
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Jeremy JY, Gadsdon P, Shukla N, Vijayan V, Wyatt M, Newby AC, Angelini GD. On the biology of saphenous vein grafts fitted with external synthetic sheaths and stents. Biomaterials 2006; 28:895-908. [PMID: 17113144 DOI: 10.1016/j.biomaterials.2006.10.023] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Accepted: 10/10/2006] [Indexed: 02/01/2023]
Abstract
Autologous saphenous vein is used as a conduit to bypass atherosclerotic lesions in both the coronary artery (coronary artery bypass graft surgery [CABG]) and in femoral arteries (infrainguinal bypass graft surgery [IIBS]). Despite the undoubted success and benefits of the procedures, graft failure occurs in 50% of cases within 10 years after surgery. A principal cause of late vein graft failure is intimal and medial hyperplasia and superimposed atherogenesis. Apart from lipid lowering therapy, no intervention has hitherto proved clinically effective in preventing late vein graft failure which clearly constitutes a major clinical and economic problem that needs to be urgently resolved. However, we have studied the effect of external synthetic stents and sheaths in pig models of vein into artery interposition grafting and found them to have a profound effect on vein graft remodelling and thickening. In this review, therefore, we will summarise the mechanisms underlying vein graft failure and how these stents influence these processes and the possible mechanisms involved as well as the application of these devices in preventing vein graft failure clinically.
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24
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Huang N, Khan A, Ashrafpour H, Neligan PC, Forrest CR, Kontos CD, Pang CY. Efficacy and mechanism of adenovirus-mediated VEGF-165 gene therapy for augmentation of skin flap viability. Am J Physiol Heart Circ Physiol 2006; 291:H127-37. [PMID: 16461370 DOI: 10.1152/ajpheart.01253.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Skin ischemic necrosis due to vasospasm and/or insufficient vascularity is the most common complication in the distal portion of the skin flap in reconstructive surgery. This project was designed to test our hypothesis that preoperative subdermal injection of adenoviral vectors encoding genes for vascular endothelial growth factor-165 (Ad.VEGF-165) or endothelial nitric oxide (NO) synthase (Ad.eNOS) effectively augments skin viability in skin flap surgery and that the mechanism of Ad.VEGF-165 gene therapy involves an increase in synthesis/release of the angiogenic and vasodilator factor NO. PBS (0.5 ml) or PBS containing Ad.VEGF-165, Ad.eNOS, or adenovirus (Ad.Null) was injected subdermally into the distal half of a mapped rat dorsal skin flap (4 × 10 cm) 7 days preoperatively, and skin flap viability was assessed 7 days postoperatively. Local subdermal gene therapy with 2 × 107–2 × 1010 plaque-forming units of VEGF-165 increased skin flap viability compared with PBS- or Ad.Null-injected control ( P < 0.05). Subdermal Ad.VEGF-165 and Ad.eNOS gene therapies were equally effective in increasing skin flap viability at 5 × 108 plaque-forming units. Subdermal Ad.VEGF-165 therapy was associated with upregulation of eNOS protein expression, Ca2+-dependent NOS activity, synthesis/release of NO, and increase in capillary density and blood flow in the distal portion of the skin flap. Injection of the NOS inhibitor Nω-nitro-l-arginine (15 mg/kg im), but not the cyclooxygenase inhibitor indomethacin (5 mg/kg im), 45 min preoperatively completely abolished the increase in skin flap blood flow and viability induced by Ad.VEGF-165 injected subdermally into the mapped skin flap 7 days preoperatively. We have demonstrated for the first time that 1) Ad.VEGF-165 and Ad.eNOS mapped skin flap injected subdermally into the mapped skin flap 7 days preoperatively are equally effective in augmenting viability in the rat dorsal skin flap compared with control, 2) the mechanism of subdermal Ad.VEGF-165 gene therapy in augmenting skin flap viability involves an increase in NO synthesis/release downstream of upregulation of eNOS protein expression and Ca2+-dependent NOS activity, and 3) the vasodilating effect of NO may predominantly mediate subdermal Ad.VEGF gene therapy in augmenting skin flap blood flow and viability.
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Affiliation(s)
- Ning Huang
- Research Institute, The Hospital for Sick Children; Department of Surgery, University of Toronto, Toronto, ON, Canada M5G 1X8
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25
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Sakaguchi T, Asai T, Belov D, Okada M, Pinsky DJ, Schmidt AM, Naka Y. Influence of ischemic injury on vein graft remodeling: role of cyclic adenosine monophosphate second messenger pathway in enhanced vein graft preservation. J Thorac Cardiovasc Surg 2005; 129:129-37. [PMID: 15632834 DOI: 10.1016/j.jtcvs.2004.04.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Endothelial injury during the harvest of saphenous vein grafts might play an important role in the development of vein graft disease after coronary artery bypass grafting. Using a murine autologous arterialized vein patch model, we tested whether the initial ischemic insult of vein grafts was linked to the later development of graft neointimal hyperplasia and whether the restoration of the cyclic adenosine monophosphate second messenger pathway would attenuate the development of neointimal hyperplasia. METHODS A segment of the external jugular vein of a mouse was grafted onto its abdominal aorta. Three weeks after the operation, the degree of neointimal hyperplasia of the implanted graft was compared among (1) grafts without preservation, (2) grafts with 2 hours of preservation (25 degrees C) in heparinized saline, and (3) grafts with 2 hours of preservation in heparinized saline in the presence of a cyclic adenosine monophosphate analog. In addition, cyclic adenosine monophosphate contents of vein grafts and leukocyte adherence to the graft endothelium were assessed. RESULTS Cyclic adenosine monophosphate contents were significantly decreased after 2 hours of preservation (212 +/- 8 vs 156 +/- 5 pmol/L, P < .01). The grafts preserved for 2 hours showed greater neointimal hyperplasia compared with the grafts without preservation (neointimal expansion, 68.7% +/- 9.6% vs 46.1% +/- 4.8%; P < .01). The addition of a cyclic adenosine monophosphate analog to the preservation solution significantly suppressed neointimal hyperplasia of grafts preserved for 2 hours (44.3% +/- 5.0%). Inhibiting the cyclic adenosine monophosphate-dependent protein kinase by adding Rp-cAMPS abrogated the beneficial effects. Furthermore, grafts preserved for 2 hours had significantly more leukocytes adhering to the graft endothelium 24 hours after the operation compared with nonpreserved grafts, which was significantly reduced by the cyclic adenosine monophosphate treatment. CONCLUSIONS Ischemic insult during vein graft harvest and preservation is a key factor in the development of vein graft neointimal hyperplasia at least in part caused by the depletion of cyclic adenosine monophosphate. We conclude that stimulation of the cyclic adenosine monophosphate second messenger pathway might be a potential strategy for the prevention of vein graft disease.
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Affiliation(s)
- Taichi Sakaguchi
- Department of Surgery, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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26
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Muzaffar S, Shukla N, Angelini GD, Jeremy JY. Inhaled prostacyclin is safe, effective, and affordable in patients with pulmonary hypertension, right-heart dysfunction, and refractory hypoxemia after cardiothoracic surgery. J Thorac Cardiovasc Surg 2005; 128:949-50. [PMID: 15573083 DOI: 10.1016/j.jtcvs.2004.05.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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27
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Abstract
The choice of the graft conduit is crucial to the success of coronary artery bypass grafting (CABG) because the patency of a coronary conduit is closely associated with an uneventful postoperative course and better long-term patient survival. From the beginning of coronary bypass surgery venous conduits particularly the great saphenous veins (GSV) have been the most frequently used coronary conduit from the beginning of the coronary bypass surgery. However, over the last decade or so, coronary bypass graft surgery with arterial revascularization of all diseased coronaries has shown to be efficient because arterial grafts have better long-term patency, especially left internal mammary artery (LIMA), compared with venous grafts. Early vein graft failure coupled with occlusion is the most important limitation of saphenous vein grafts. Nevertheless, vein grafting is still an integral part of cardiac surgical practice. This review provides a summary of the patency rates, technical features and certain characteristics of the venous conduits. It also examines the current understanding and knowledge of venous histology, vein graft pathology and the associated endothelial and smooth muscle cell physiology and pharmacology. In addition, the existing and the emerging strategies to combat and control vein graft intimal hyperplasia and accelerated atherosclerosis are reviewed in detail.
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Affiliation(s)
- Shahzad Gull Raja
- Department of Cardiovascular Surgery, King Edward Medical College, Mayo Hospital, Lahore, Pakistan
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28
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Khan A, Ashrafpour H, Huang N, Neligan PC, Kontos C, Zhong A, Forrest CR, Pang CY. Acute local subcutaneous VEGF165 injection for augmentation of skin flap viability: efficacy and mechanism. Am J Physiol Regul Integr Comp Physiol 2004; 287:R1219-29. [PMID: 15217788 DOI: 10.1152/ajpregu.00143.2004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Distal skin ischemic necrosis is a common complication in skin flap surgery. The pathogenesis of skin flap ischemic necrosis is unclear, and there is no clinical treatment available. Here, we used the 4 × 10 cm rat dorsal skin flap model to test our hypothesis that subcutaneous injection of vascular endothelial growth factor 165 (VEGF165) in skin flaps at the time of surgery is effective in augmentation of skin flap viability, which is associated with an increase in nitric oxide (NO) production, and the mechanism involves 1) an increase in skin flap blood flow in the early stage after surgery and 2) enhanced angiogenesis subsequently to sustain increased skin flap blood flow and viability. We observed that subcutaneous injection of VEGF165 in skin flaps at the time of surgery increased skin flap viability in a dose-dependant manner. Subcutaneous injection of VEGF165 at the dose of 2 μg/flap increased skin flap viability by 28% ( P < 0.05; n = 8). Over 80% of this effect was blocked by intramuscular injection of the NO synthase (NOS) inhibitor Nω-nitro-l-arginine (13 mg/kg) 45 min before surgery ( P < 0.05; n = 8). The VEGF165 treatment also increased skin flap blood flow (2.68 ± 0.63 ml·min−1·100 g−1) compared with the control (1.26 ± 0.10 ml·min−1·100 g−1; P < 0.05, n = 6) assessed 6 h postoperatively. There was no change in skin flap capillary density at this time point. VEGF165-induced increase in capillary density (32.2 ± 1.1 capillaries/mm2; P < 0.05, n = 7) compared with control (24.6 ± 1.4 capillaries/mm2) was seen 7 days postoperatively. There was also evidence to indicate that VEGF165-induced NO production in skin flaps was stimulated by activation of NOS activity followed by upregulation of NOS protein expression. These observations support our hypothesis and for the first time provide an important insight into the mechanism of acute local VEGF165 protein therapy in mitigation of skin flap ischemic necrosis.
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Affiliation(s)
- Asim Khan
- Research Institute, The Hospital for Sick Children, University of Toronto, Ontario, Canada M5G 1X8
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29
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Raja SG, Haider Z, Ahmad M, Zaman H. Saphenous Vein Grafts: to Use or Not to Use? Heart Lung Circ 2004; 13:150-6. [PMID: 16352186 DOI: 10.1016/j.hlc.2004.03.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2002] [Revised: 01/18/2004] [Accepted: 03/05/2004] [Indexed: 11/21/2022]
Abstract
The choice of the graft conduit is crucial to the success of coronary artery bypass grafting (CABG) because the patency of a coronary conduit is closely associated with an uneventful postoperative course and better long-term patient survival. From the beginning of coronary bypass surgery venous conduits particularly the great saphenous vein (GSV) has been the most frequently used coronary conduit. However, over the last decade or so, coronary bypass graft surgery with arterial revascularization of all diseased coronaries has shown to be efficient because arterial grafts have better long-term patency, especially left internal mammary artery (LIMA), compared with venous grafts. Early vein graft failure coupled with occlusion is the most important limitation of saphenous vein grafts. Nevertheless, vein grafting is still an integral part of cardiac surgical practice. This review provides a summary of the patency rates, technical features and certain characteristics of the venous conduits. It also examines the current understanding and knowledge of venous histology, vein graft pathology and the associated endothelial and smooth muscle cell physiology and pharmacology. In addition, the existing and the emerging strategies to combat and control vein graft intimal hyperplasia and accelerated atherosclerosis are reviewed in detail.
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Affiliation(s)
- Shahzad G Raja
- Department of Cardiovascular Surgery, Mayo Hospital, Lahore, Pakistan.
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Ashrafpour H, Huang N, Neligan PC, Forrest CR, Addison PD, Moses MA, Levine RH, Pang CY. Vasodilator effect and mechanism of action of vascular endothelial growth factor in skin vasculature. Am J Physiol Heart Circ Physiol 2004; 286:H946-54. [PMID: 14644765 DOI: 10.1152/ajpheart.00901.2003] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Various laboratories have reported that local subcutaneous or subdermal injection of VEGF165 at the time of surgery effectively attenuated ischemic necrosis in rat skin flaps, but the mechanism was not studied and enhanced angiogenesis was implicated. In the present study, we used the clinically relevant isolated perfused 6 × 16-cm pig buttock skin flap model to 1) test our hypothesis that VEGF165 is a potent vasodilator and acute VEGF165 treatment increases skin perfusion; and 2) investigate the mechanism of VEGF165-induced skin vasorelaxation. We observed that VEGF165 (5 × 10–16–5 × 10–11 M) elicited a concentration-dependent decrease in perfusion pressure (i.e., vasorelaxation) in skin flaps preconstricted with a submaximal concentration of norepinephrine (NE), endothelin-1, or U-46619. The VEGF165-induced skin vasorelaxation was confirmed using a dermofluorometry technique for assessment of skin perfusion. The vasorelaxation potency of VEGF165 in NE-preconstricted skin flaps (pD2 = 13.57 ± 0.31) was higher ( P < 0.05) than that of acetylcholine (pD2 = 7.08 ± 0.24). Human placental factor, a specific VEGF receptor-1 agonist, did not elicit any vasorelaxation effect. However, a specific antibody to VEGF receptor-2 (1 μg/ml) or a specific VEGF receptor-2 inhibitor (5 × 10–6 M SU-1498) blocked the vasorelaxation effect of VEGF165 in NE-preconstricted skin flaps. These observations indicate that the potent vasorelaxation effect of VEGF165 in the skin vasculature is initiated by the activation of VEGF receptor-2. Furthermore, using pharmacological probes, we observed that the postreceptor signaling pathways of VEGF165-induced skin vasorelaxation involved activation of phospholipase C and protein kinase C, an increase in inositol 1,4,5-trisphosphate activity, release of the intra-cellular Ca2+ store, and synthesis/release of endothelial nitric oxide, which predominantly triggered the effector mechanism of VEGF165-induced vasorelaxation. This information provides, for the first time, an important insight into the mechanism of VEGF165 protein or gene therapy in the prevention/treatment of ischemia in skin flap surgery and skin ischemic diseases.
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Affiliation(s)
- Homa Ashrafpour
- The Hospital for Sick Children, 555 University Ave., Toronto, Ontario, Canada M5G 1X8
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Sperry JL, Deming CB, Bian C, Walinsky PL, Kass DA, Kolodgie FD, Virmani R, Kim AY, Rade JJ. Wall tension is a potent negative regulator of in vivo thrombomodulin expression. Circ Res 2003; 92:41-7. [PMID: 12522119 DOI: 10.1161/01.res.0000048196.11060.a0] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Thrombomodulin (TM), a key component of the anticoagulant protein C pathway, is a major contributor to vascular thromboresistance. We previously found that TM protein expression is dramatically reduced in autologous vein grafts during the first two weeks after implantation, coincident to a local inflammatory response, and remains suppressed for at least 6 weeks. To determine the proximate cause of TM loss, in vivo gene expression was quantified by real-time PCR. TM gene expression in vein grafts declined >85% during the first postoperative week and remained suppressed >55% at 6 weeks, accounting for the observed changes in protein expression. The effects of vein graft inflammation were evaluated in animals rendered leukopenic with vinblastine before graft implantation. Abrogating the local inflammatory response affected neither TM protein nor gene expression. To determine how hemodynamic forces might modulate TM expression, the surgical protocol was modified to alter blood flow and pressure-induced vessel distension. TM protein and gene expression did not correlate to changes in shear stress but highly correlated to changes in wall tension, both acutely and over time. We conclude that the primary stimulus for altered TM expression in vein grafts is the exposure to arterial pressure. Furthermore, these data identify strain as a novel and important pathway for in vivo TM gene regulation.
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Affiliation(s)
- Jason L Sperry
- Division of Cardiology of the Johns Hopkins School of Medicine, Baltimore, Md 21287, USA
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Lardenoye JHP, De Vries MR, Grimbergen JM, Havekes LM, Knaapen MWM, Kockx MM, van Hinsbergh VWM, van Bockel JH, Quax PHA. Inhibition of accelerated atherosclerosis in vein grafts by placement of external stent in apoE*3-Leiden transgenic mice. Arterioscler Thromb Vasc Biol 2002; 22:1433-8. [PMID: 12231562 DOI: 10.1161/01.atv.0000030339.79524.6e] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Vein grafts fail because of the development of intimal hyperplasia and accelerated atherosclerosis. Placement of an external stent around vein grafts resulted in an inhibition of intimal hyperplasia in several animal studies. Here, we assess the effects of external stenting on accelerated atherosclerosis in early vein grafts in carotid arteries in hypercholesterolemic apolipoprotein E*3-Leiden transgenic mice. METHODS AND RESULTS Venous interposition grafting was performed in apolipoprotein E*3-Leiden mice fed standard chow or a highly cholesterol-rich diet for 4 weeks. After engraftment, external stents with different inner diameters (0.4 or 0.8 mm) were placed. In unstented vein grafts in hypercholesterolemic mice, thickening up to 50 times the original thickness, with foam cell-rich lesions, calcification, and necrosis, was observed within 28 days. The atherosclerotic lesions observed show high morphological resemblance to atherosclerotic lesions observed in human vein grafts. In stented vein grafts in hypercholesterolemic mice, no foam cell accumulation or accelerated atherosclerosis was observed. Compared with unstented vein grafts, stenting of vein grafts in a hypercholesterolemic environment resulted in a 94% reduction of vessel wall thickening. These effects were independent of stent size. CONCLUSIONS Extravascular stent placement results in strong inhibition of accelerated vein graft atherosclerosis in hypercholesterolemic transgenic mice and thereby provides a perspective for therapeutic intervention in vein graft diseases.
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Vijayan V, Smith FCT, Angelini GD, Bulbulia RA, Jeremy JY. External supports and the prevention of neointima formation in vein grafts. Eur J Vasc Endovasc Surg 2002; 24:13-22. [PMID: 12127843 DOI: 10.1053/ejvs.2002.1676] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
AIMS AND METHODOLOGY the aim of this review is to provide an overview of the aetiology of neointima formation in vein grafts and to highlight the use of an external support to modulate this phenomenon. A systematic literature review was performed via computerised search on MEDLINE, OVID and the Cochrane Library. The search terms initially employed were broad-based; "vein graft", "neointima" and "external stent". Subsequently, more specific search terms were utilised; "perivenous mesh", "external prosthesis" and "varicose vein". Articles from indexed journals relevant to the objective, external venous supports, from the earliest reports in the 1960's to the latest in 2001 were included to obtain an exhaustive list. Reviews, abstracts and proceedings of scientific meetings, case reports and the results of both animal model investigations and human clinical trials in all languages were included. Articles describing an external support employed in both peripheral and aortocoronary bypass investigations were included.
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Affiliation(s)
- V Vijayan
- Vascular Studies Unit, Bristol Royal Infirmary, Bristol, UK
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Tsui JCS, Dashwood MR. Recent strategies to reduce vein graft occlusion: a need to limit the effect of vascular damage. Eur J Vasc Endovasc Surg 2002; 23:202-8. [PMID: 11914005 DOI: 10.1053/ejvs.2002.1600] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Despite early identification and aggressive modification of atherosclerotic risk factors, many patients still require surgical revascularisation for established atherosclerotic vascular disease. However, bypass surgery is hampered by a high incidence of vein graft failure. New strategies are being introduced to improve these results, with early data suggesting that improved patency rates are possible. These vary from the use of adjuvant pharmacological agents and local gene transfer strategies to the modification of vein harvesting techniques in order to reduce vascular damage to all layers of the graft. Advances in vascular biology have resulted in new insights into the role of the endothelium and adventitia in vein graft remodelling. Although recent pharmacological adjuvant therapy and molecular techniques have been described that may be used to reduce the incidence of vein graft occlusion a more desirable approach for improved graft patency rates may be achieved simply by using atraumatic surgical techniques aimed at minimising vascular damage during vessel harvesting and subsequent anastamoses during bypass surgery.
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Affiliation(s)
- J C S Tsui
- Department of Surgery, Royal Free and University College London Medical School, London, NW3 2QG, UK
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Tsui JC, Souza DS, Filbey D, Bomfim V, Dashwood MR. Preserved endothelial integrity and nitric oxide synthase in saphenous vein grafts harvested by a 'no-touch' technique. Br J Surg 2001; 88:1209-15. [PMID: 11531869 DOI: 10.1046/j.0007-1323.2001.01855.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The saphenous vein is the most commonly used conduit for coronary artery bypass surgery, but 1-year occlusion rates as high as 30 per cent have been reported. In conventional surgery, considerable damage to the vein occurs during harvesting. The aim of this study was to compare endothelial integrity and nitric oxide synthase (NOS) in saphenous veins harvested by a novel 'no-touch' technique and veins harvested conventionally. METHODS Immunohistochemistry was used to study endothelial integrity, and a combination of histochemistry and autoradiography was employed to identify NOS in human saphenous veins harvested by conventional and no-touch techniques. RESULTS The endothelial lining of conventional grafts was reduced compared with that of no-touch grafts (52 versus 73 per cent; P = 0.04). This was associated with a concomitant reduction of NOS availability; NOS was also present in the adventitial vasa vasorum of no-touch vessels. CONCLUSION Some of the sites with potential for nitric oxide release in vivo are removed during conventional saphenous vein harvesting. These sites were preserved after no-touch harvesting, suggesting the potential to improve coronary artery bypass graft patency.
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Affiliation(s)
- J C Tsui
- Department of Surgery, Royal Free and University College Medical School, London, UK
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Chardigny CI, Van der Perre K, Simonet S, Descombes JJ, Fabiani JN, Verbeuren TJ. Platelets and prostacyclin in arterial bypasses: implications for coronary artery surgery. Ann Thorac Surg 2000; 69:513-9. [PMID: 10735690 DOI: 10.1016/s0003-4975(99)01304-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND We investigated effects of platelets and prostacyclin formation in human internal mammary (IMA) and radial (RA) arteries. METHODS IMA and RA segments were suspended in organ bath with increasing concentrations of platelets. Experiments were applied with and without ketanserin, a 5HT2 receptor antagonist, or U3405, a TXA2 receptor antagonist. The release of prostacyclin (PGI2) was assessed by enzyme immunoassay in vessels without endothelium, before and after contraction with angiotensin (AT) I-II. RESULTS In IMA and RA with endothelium, platelets caused contractions, significantly enhanced in arteries without endothelium. Contractions to platelets were higher in RA than in IMA. U3405 reduced the platelet induced contractions in RA but not in IMA. Ketanserin inhibited the platelet induced contractions in IMA and RA. The basal release of PGI2 was more important in IMA than in RA. Addition of AT/I-II significantly reduced the release of PGI2 in IMA but not in RA. CONCLUSIONS The RA responds more powerfully to platelets than IMA. Protective system with PGI2 seems to be more powerless in RA than in IMA. This accentuates the importance of antispastic and antiplatelet drugs when arteries are used for coronary artery bypass surgery.
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Affiliation(s)
- C I Chardigny
- Division of Angiology, Institut de Recherches Servier, Suresnes, France
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Gutterman DD. Adventitia-dependent influences on vascular function. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:H1265-72. [PMID: 10516160 DOI: 10.1152/ajpheart.1999.277.4.h1265] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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