1
|
Mikami T, Dashwood MR, Kawaharada N, Furuhashi M. An Obligatory Role of Perivascular Adipose Tissue in Improved Saphenous Vein Graft Patency in Coronary Artery Bypass Grafting. Circ J 2023:CJ-23-0581. [PMID: 37914280 DOI: 10.1253/circj.cj-23-0581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
The gold standard graft for coronary artery bypass grafting (CABG) is the internal thoracic artery (ITA), and the second recommendation is the radial artery. However, complete revascularization with arterial grafts alone is often difficult, and the saphenous vein (SV) is the most commonly used autologous graft for CABG, because it is easier to use without restriction for the length of the graft. On the other hand, the patency of SV grafts (SVGs) is poor compared with that of arterial grafts. The SVG is conventionally harvested as a distended conduit with surrounding tissue removed, a procedure that may cause vascular damage. A no-touch technique of SVG harvesting has been reported to result in improved long-term patency in CABG comparable to that when using the ITA for grafting. Possible reasons for the excellent long-term patency of no-touch SVGs are the physical support provided by preserved surrounding perivascular adipose tissue, preservation of the vascular wall structure including the vasa vasorum, and production of adipocyte-derived factors. In this review, we discuss recent strategies aimed at improving the performance of SVGs, including no-touch harvesting, minimally invasive harvesting and mechanical support using external stents.
Collapse
Affiliation(s)
- Takuma Mikami
- Department of Cardiovascular Surgery, Sapporo Medical University
| | - Michael R Dashwood
- Surgical and Interventional Sciences, Royal Free Hospital Campus, University College London Medical School
| | | | - Masato Furuhashi
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University
| |
Collapse
|
2
|
Dashwood MR, Pinheiro BB, Souza DS. Impact of saphenous vein harvesting on graft diameter: Supporting the no-touch technique. JTCVS Tech 2022; 16:105-106. [PMID: 36510541 PMCID: PMC9735316 DOI: 10.1016/j.xjtc.2022.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Michael R. Dashwood
- Surgical and Interventional Sciences, Royal Free Hospital Campus, University College London Medical School, London, United Kingdom
| | - Bruno Botelho Pinheiro
- Department of Cardiovascular Surgery, Hospital do Coração Anis Rassi, Goiânia, Goiás, Brazil
| | - Domingos S.R. Souza
- Department of Cardiothoracic and Vascular Surgery, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| |
Collapse
|
3
|
Shen L, Dashwood MR, Casale C, Orie NN, Evans IM, Sufi P, Gray R, Mohamed-Ali V. Depot- and diabetes-specific differences in norepinephrine-mediated adipose tissue angiogenesis, vascular tone, collagen deposition and morphology in obesity. Life Sci 2022; 305:120756. [PMID: 35780713 DOI: 10.1016/j.lfs.2022.120756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 06/18/2022] [Accepted: 06/27/2022] [Indexed: 11/17/2022]
Abstract
AIMS Norepinephrine (NE) is a known regulator of adipose tissue (AT) metabolism, angiogenesis, vasoconstriction and fibrosis. This may be through autocrine/paracrine effects on local resistance vessel function and morphology. The aims of this study were to investigate, in human subcutaneous and omental adipose tissue (SAT and OAT): NE synthesis, angiogenesis, NE-mediated arteriolar vasoconstriction, the induction of collagen gene expression and its deposition in non-diabetic versus diabetic obese subjects. MATERIALS AND METHODS SAT and OAT from obese patients were used to investigate tissue NE content, tyrosine hydroxylase (TH) density, angiogenesis including capillary density, angiogenic capacity and angiogenic gene expression, NE-mediated arteriolar vasoconstriction and collagen deposition. KEY FINDINGS In the non-diabetic group, NE concentration, TH immunoreactivity, angiogenesis and maximal vasoconstriction were significantly higher in OAT compared to SAT (p < 0.05). However, arterioles from OAT showed lower NE sensitivity compared to SAT (10-8 M to 10-7.5 M, p < 0.05). A depot-specific difference in collagen deposition was also observed, being greater in OAT than SAT. In the diabetic group, no significant depot-specific differences were seen in NE synthesis, angiogenesis, vasoconstriction or collagen deposition. SAT arterioles showed significantly lower sensitivity to NE (10-8 M to 10-7.5 M, p < 0.05) compared to the non-diabetic group. SIGNIFICANCE SAT depot in non-diabetic obese patients exhibited relatively low NE synthesis, angiogenesis, tissue fibrosis and high vasoreactivity, due to preserved NE sensitivity. The local NE synthesis in OAT and diabetes desensitizes NE-induced vasoconstriction, and may also explain the greater tissue angiogenesis and fibrosis in these depots.
Collapse
Affiliation(s)
- Lei Shen
- Rayne Building, University College London, London, UK.
| | | | - Carlo Casale
- Rayne Building, University College London, London, UK
| | - Nelson N Orie
- Royal Free Campus, University College London, London, UK; Anti-Doping Lab Qatar, Doha, Qatar
| | - Ian M Evans
- Cancer Stem Cell Team, Institute of Cancer Research, London, UK
| | | | - Rosaire Gray
- Rayne Building, University College London, London, UK; Whittington Hospital, London, UK
| | - Vidya Mohamed-Ali
- Royal Free Campus, University College London, London, UK; Anti-Doping Lab Qatar, Doha, Qatar
| |
Collapse
|
4
|
Dashwood MR, Samano N, Souza DS. Saphenous vein harvesting for CABG: wear a VEST or keep the fat? Eur J Cardiothorac Surg 2022; 62:6608695. [PMID: 35703951 DOI: 10.1093/ejcts/ezac349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 06/13/2022] [Indexed: 01/07/2023]
Affiliation(s)
- Michael R Dashwood
- Surgical and Interventional Sciences, Royal Free Hospital Campus, University College Medical School, London, UK
| | - Ninos Samano
- Department of Cardiothoracic and Vascular Surgery and University Health Care Research Center, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Domingos S Souza
- Department of Cardiothoracic and Vascular Surgery and University Health Care Research Center, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| |
Collapse
|
5
|
Dashwood MR, Pinheiro BB, Souza DSR. Thirty Years of No-Touch Saphenous Vein Harvesting: A Timely Jubilee Gift. Circulation 2022; 145:319-320. [PMID: 35100022 DOI: 10.1161/circulationaha.121.057959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Michael R Dashwood
- Surgical and Interventional Sciences, Royal Free Hospital Campus, University College London Medical School, United Kingdom (M.R.D.)
| | - Bruno Botelho Pinheiro
- Department of Cardiovascular Surgery, Hospital do Coração Anis Rassi, Goiânia, Goiás, Brazil (B.B.P.)
| | - Domingos S R Souza
- Department of Cardiothoracic and Vascular Surgery, Faculty of Medicine and Health, Örebro University, Sweden (D.S.R.S.)
| |
Collapse
|
6
|
Dashwood MR. No-Touch Saphenous Vein — Vascular Damage and the London Connection. Braz J Cardiovasc Surg 2022; 37:1-6. [PMID: 36053997 PMCID: PMC9454283 DOI: 10.21470/1678-9741-2022-0024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In this review, I summarise the circumstances leading to the collaboration
between London and Örebro on the basic research performed to study
potential mechanisms underlying the improved patency of saphenous veins
harvested by the no-touch technique. Histological studies reveal various forms
of vascular damage to saphenous vein grafts harvested in conventional coronary
artery bypass grafting (CABG) whereas no-touch grafts retain a normal
architecture. The perivascular fat that remains intact on no-touch saphenous
vein grafts seems to play a particularly important role as the “protector” of
all layers of the graft. In addition, the perivascular fat is a source of
adipose cell-derived factors that may contribute to the success of the no-touch
technique. While a number of trials have compared no-touch with conventional
grafts following CABG, these have generally been limited to short follow-up
periods, low patient numbers, and inadequate histological data. When handling
no-touch saphenous vein at harvesting, there is no direct contact of the vein by
surgical instruments, spasm does not occur, and high-pressure intraluminal
distension is not required. While damage to both endothelial and vascular smooth
muscle cells are evident at the microscopic and ultrastructural level in
conventional saphenous vein grafts, their structure in no-touch grafts is
preserved. Also, in no-touch veins, the vasa vasorum remains intact and
transmural blood supply is maintained. This microvascular network is disrupted
during conventional harvesting, a situation likely to stimulate processes
involved in graft occlusion. The use of excess graft material for histology is
to be encouraged for the assessment of vascular damage and even surgeon
competence. If you don’t look, you don’t find.
Collapse
|
7
|
Kopjar T, Dashwood MR. Towards Endoscopic No-Touch Saphenous Vein Graft Harvesting in Coronary Bypass Surgery. Braz J Cardiovasc Surg 2022; 37:57-65. [PMID: 36054003 PMCID: PMC9454289 DOI: 10.21470/1678-9741-2022-0144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The saphenous vein is the most used conduit for coronary artery bypass surgery.
However, the patency rate of this graft is inferior to the internal thoracic
artery patency rate, which is the gold standard. Using the conventional
technique, the saphenous vein is harvested via a large open incision and excised
in such a way that causes both vascular damage and wound healing complications.
Consequently, vein graft patency and surgical site infection may be compromised.
Graft patency is markedly improved when the saphenous vein is harvested
atraumatically with minimal damage and with surrounding cushion of perivascular
fat intact. However, despite the improved graft performance, wound healing
complications and infection remain a problem. Although wound healing
complication is reduced when using endoscopic vein harvesting, there may be a
negative impact on graft performance. This is due to vascular damage associated
with application of forces to the vein that are usually avoided in open vein
harvesting, including traction, adventitial stripping, and venous compression.
There is evidence to suggest that improved patency of endoscopically harvested
saphenous veins is associated with the surgeon’s experience of the technique.
Recently, endoscopic methods of harvesting have been described where the
saphenous vein is removed intact and with minimal vascular damage caused. In
addition, wound healing complications, infection, and scarring are reduced.
While the effect of these techniques on vein graft patency have yet to be
reported, the ability to obtain a superior graft with reduced wound
complications will be of great benefit to patients undergoing coronary
revascularization procedures.
Collapse
|
8
|
Furuhashi M, Mikami T, Kawaharada N, Dashwood MR. Saphenous vein harvesting: Meta-analysis, metaflammation, and adipose tissue remodeling. J Card Surg 2021; 36:4832-4833. [PMID: 34505735 DOI: 10.1111/jocs.15991] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 08/17/2021] [Indexed: 11/29/2022]
Affiliation(s)
- Masato Furuhashi
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Takuma Mikami
- Department of Cardiovascular Surgery, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Nobuyoshi Kawaharada
- Department of Cardiovascular Surgery, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Michael R Dashwood
- Surgical and Interventional Sciences, Royal Free Hospital Campus, University College Medical School, London, UK
| |
Collapse
|
9
|
Dashwood MR, Loesch A, Souza DS. HArVeSTing vein grafts under different preparative techniques: Raising more questions than answers. J Card Surg 2021; 36:3019-3020. [PMID: 33938585 DOI: 10.1111/jocs.15594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 03/29/2021] [Indexed: 11/29/2022]
Affiliation(s)
- Michael R Dashwood
- Surgical and Interventional Sciences, Royal Free Hospital Campus, University College Medical School, London, UK
| | - Andrzej Loesch
- Centre for Rheumatology, Royal Free Hospital Campus, University College Medical School, London, UK
| | - Domingos S Souza
- Department of Cardiothoracic and Vascular Surgery, Örebro University, Örebro, Sweden
| |
Collapse
|
10
|
Abstract
The saphenous vein is the most commonly used conduit for coronary artery bypass grafting. Arterial grafts are harvested with the outer pedicle intact whereas saphenous veins are harvested with the pedicle removed in the conventional graft harvesting technique. This conventional procedure causes considerable vascular damage. One strategy to improve vein graft patency has been to provide external support. Ongoing studies show that fitting a metal external support improves conventionally harvested saphenous vein graft patency. On the other hand, the no-touch technique of harvesting the saphenous vein provides an improved graft with long-term patency comparable to that of the internal mammary artery. This improvement is suggested to be due to preservation of vessel structures. Interestingly, many of the mechanisms proposed to be associated with the beneficial actions of an artificial external support on saphenous vein graft patency are similar to those underlying the beneficial effect of no-touch saphenous vein grafts where the intact outer layer acts as a natural support. Additional actions of external supports have been advocated, including promotion of angiogenesis, increased production of vascular-protective factors, and protection of endothelial cells. Using no-touch harvesting, normal vascular architecture is maintained, tissue and cell damage is minimized, and factors beneficial for graft patency are preserved. In this review, the significance of external support of saphenous vein grafts in coronary artery bypass grafting is discussed.
Collapse
Affiliation(s)
- Ninos Samano
- Department of Cardiothoracic and Vascular Surgery and University Health Care Research Center, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Domingos Souza
- Department of Cardiothoracic and Vascular Surgery and University Health Care Research Center, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Michael R Dashwood
- Surgical and Interventional Sciences, Royal Free Hospital Campus, University College Medical School, London, UK
| |
Collapse
|
11
|
Abstract
It has been reported that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection induces endothelial inflammation, therefore facilitating the progression of endothelial and vascular dysfunction in coronavirus disease 2019 (COVID-19) patients. Coronary artery bypass grafting (CABG) involves mainly the use of the saphenous vein (SV) and internal mammary artery as graft material in the stenosed coronary arteries. Unfortunately, graft patency of the SV is low due to endothelial dysfunction and inflammation. We propose that SARS-CoV-2 might cause vascular inflammation, endothelial dysfunction, and thrombosis in coronary artery bypass graft vessels by binding angiotensin-converting enzyme 2 receptor. Therefore, in this Special Article, we consider the potential influence of COVID-19 on the patency rates of coronary artery bypass graft vessels, mainly with reference to the SV. Moreover, we discuss the technique of SV graft harvesting and the therapeutic potential of focusing on endothelial dysfunction, vascular inflammation, and thrombosis for protecting coronary artery bypass grafts in COVID-19 infected CABG patients.
Collapse
Affiliation(s)
- Gokce Topal
- Istanbul University Faculty of Pharmacy Department of Pharmacology Istanbul Turkey Department of Pharmacology, Faculty of Pharmacy, Istanbul University, Istanbul, Turkey
| | - Andrzej Loesch
- University College Medical School Royal Free Hospital Campus Centre for Rheumatology London United Kingdom Centre for Rheumatology, Royal Free Hospital Campus, University College Medical School, London, United Kingdom
| | - Michael R Dashwood
- University College Medical School Royal Free Hospital Campus Department of Surgical and Interventional Sciences London United Kingdom Department of Surgical and Interventional Sciences, Royal Free Hospital Campus, University College Medical School, London, United Kingdom
| |
Collapse
|
12
|
Dashwood MR, Loesch A. Endothelin-1, endothelin receptor antagonists, and vein graft occlusion in coronary artery bypass surgery: 20 years on and still no journey from bench to bedside. Can J Physiol Pharmacol 2020; 98:570-578. [PMID: 32343914 DOI: 10.1139/cjpp-2019-0598] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The saphenous vein is the most commonly used bypass graft in patients with coronary artery disease. During routine coronary artery bypass, grafting the vascular damage inflicted on the vein is likely to stimulate the release of endothelin-1, a potent endothelium-derived vasoconstrictor that also possesses cell proliferation and inflammatory properties, conditions associated with vein graft failure. In both in vitro and in vivo studies, endothelin receptor antagonists reduce neointimal thickening. The mechanisms underlying these observations are multifactorial and include an effect on cell proliferation and cell/tissue damage. Much of the data supporting the beneficial action of endothelin-1 receptor antagonism at reducing intimal thickening and occlusion in experimental vein grafts were published over 20 years ago. The theme of the recent ET-16 conference in Kobe was "Visiting Old and Learning New". This short review article provides an overview of studies showing the potential of endothelin receptor antagonists to offer an adjuvant therapeutic approach for reducing saphenous vein graft failure and poses the question why this important area of research has not been translated from bench to bedside given the potential benefit for coronary artery bypass patients.
Collapse
Affiliation(s)
- Michael R Dashwood
- Surgical and Interventional Sciences, Royal Free Hospital Campus, University College Medical School, London, United Kingdom
| | - Andrzej Loesch
- Centre for Rheumatology, Royal Free Hospital Campus, University College Medical School, London, United Kingdom
| |
Collapse
|
13
|
Dashwood MR. Why 'EXTENT' for coronary artery bypass surgery when the saphenous vein should need no support? Eur J Cardiothorac Surg 2019; 55:1021. [PMID: 30534985 DOI: 10.1093/ejcts/ezy412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 11/06/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Michael R Dashwood
- Division of Surgery and Interventional Science, University College London Medical School, London, UK
| |
Collapse
|
14
|
Dashwood MR, Loesch A. Arterial versus venous conduits in coronary artery bypass surgery: Comparing apples with oranges. J Thorac Cardiovasc Surg 2019; 157:e253-e254. [PMID: 30745049 DOI: 10.1016/j.jtcvs.2018.11.047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 11/13/2018] [Indexed: 11/19/2022]
Affiliation(s)
- Michael R Dashwood
- Surgical and Interventional Sciences, Royal Free Hospital Campus, University College Medical School, London, United Kingdom
| | - Andrzej Loesch
- Centre for Rheumatology, Royal Free Hospital Campus, University College Medical School, London, United Kingdom
| |
Collapse
|
15
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
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.
| |
Collapse
|
16
|
Lohsiriwat V, Wilson VG, Scholefield JH, Dashwood MR. Regional Distribution of Nitric Oxide Synthase in Human Anorectal Tissue: A Pilot Study on the Potential Role for Nitric Oxide in Haemorrhoids. Curr Vasc Pharmacol 2018; 18:43-49. [PMID: 30058493 DOI: 10.2174/1570161116666180730101532] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 07/25/2018] [Accepted: 07/26/2018] [Indexed: 12/15/2022]
Abstract
OBJECTIVE To study the distribution of nitric oxide synthase (NOS) isoforms and protein levels in human haemorrhoids and rectal tissue. METHODS Protein expression of NOS1, NOS2 and NOS3 was compared between haemorrhoids (n=14) and normal rectal submucosa (n=6) using Western blot analysis. The localisation of all NOS isoforms to specific structures was determined by immunohistochemistry. RESULTS Western blot analysis showed median (interquartile range) protein levels of all NOS isoforms were 1.5-2.4 times higher in haemorrhoids than rectal tissue; 121.4 (55.2-165.5) vs 50.0 (25.5-73.7) for NOS1 (p=0.020), 32.2 (23.8-140.6) vs 14.8 (9.6-34.0) for NOS2 (p=0.109), and 80.1 (62.0-139.5) vs 54.3 (48.7 -61.7) for NOS3 (p=0.015). Immunohistochemistry revealed a different distribution and location of all NOS isoforms in vascular and non-vascular structure of haemorrhoids and rectal tissues. The number of haemorrhoid specimens showing positive immunoreactivity of NOS in the vascular endothelium was significantly higher than that in rectal tissue for NOS1 (11/14 (79%) vs 1/6 (17%); p=0.018) and NOS3 (8/14 (57%) vs 0/6 (0%); p=0.042), but not for NOS2 (6/14 (43%) vs 4/6 (67%); p=0.63). CONCLUSION Haemorrhoids have significantly higher protein levels of NOS1 and NOS3 than rectal tissue. The vascular endothelium of haemorrhoids also has significantly higher positive immunoreactivity of NOS1 and NOS3 than rectal tissue suggesting that blood vessels in haemorrhoids are exposed to higher NO concentrations than those of rectal tissue. Since haemorrhoids exhibit marked vascular dilatation and present with bleeding or swelling, a reduction in NOS - by applying NOS inhibitors - may potentially improve the symptoms of haemorrhoids.
Collapse
Affiliation(s)
- Varut Lohsiriwat
- The University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom.,Department of Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Vincent G Wilson
- The University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom
| | - John H Scholefield
- The University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom
| | - Michael R Dashwood
- Surgical and Interventional Sciences, Royal Free and University College Medical School, London, United Kingdom
| |
Collapse
|
17
|
Barton M, Little HJ, Vaughan-Jones RD, Daniels S, Dashwood MR, Tsui JC. Sidney George Shaw, DPhil (1948-2017). Physiol Res 2018; 67:S27-S35. [PMID: 31774298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023] Open
Abstract
On March 4, 2017 at the age of 68, Sidney George Shaw (Sid) unexpectedly died from complications following surgery, only four years after retiring from the University of Bern. Trained in biochemistry at Oxford University, Sid had quickly moved into molecular pharmacology and became a key investigator in the field of enzyme biochemistry, vasoactive peptide research, and receptor signaling. Sid spent half his life in Switzerland, after moving to the University of Bern in 1984. This article, written by his friends and colleagues who knew him and worked with him during different stages of his career, summarizes his life, his passions, and his achievements in biomedical research. It also includes personal memories relating to a dear friend and outstanding scientist whose intellectual curiosity, humility, and honesty will remain an example to us all.
Collapse
Affiliation(s)
- M Barton
- Molecular Internal Medicine, University of Zürich, Zürich, Switzerland. , Division of Surgery and Interventional Science, University College London, Royal Free Campus, London, United Kingdom.
| | | | | | | | | | | |
Collapse
|
18
|
Affiliation(s)
- Andrzej Loesch
- Centre for Rheumatology, Royal Free Hospital Campus, University College Medical School, London, United Kingdom
| | - Michael R Dashwood
- Surgical and Interventional Sciences, Royal Free Hospital Campus, University College Medical School, Pond St, London NW3 2QG, United Kingdom.
| |
Collapse
|
19
|
Fernandez-Alfonso MS, Souza DSR, Dreifaldt M, Dashwood MR. Commentary: Perivascular Fat and Improved Vein Graft Patency in Patients Undergoing Coronary Artery Bypass Surgery. Curr Vasc Pharmacol 2018; 14:308-12. [PMID: 27173025 DOI: 10.2174/1570161114666160513150444] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | | | | | - Michael R Dashwood
- Royal Free Hospital Campus, University College Medical School, Surgical and Interventional Sciences, Pond Street, London NW3 2QG, United Kingdom.
| |
Collapse
|
20
|
Ramos De Souza D, Dashwood MR, Samano N. Saphenous vein graft harvesting and patency: No-touch harvesting is the answer. J Thorac Cardiovasc Surg 2017; 154:1300-1301. [DOI: 10.1016/j.jtcvs.2017.02.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 01/09/2017] [Accepted: 02/04/2017] [Indexed: 11/16/2022]
|
21
|
Loesch A, Dashwood MR. Nerve-perivascular fat communication as a potential influence on the performance of blood vessels used as coronary artery bypass grafts. J Cell Commun Signal 2017; 12:181-191. [PMID: 28601937 PMCID: PMC5842173 DOI: 10.1007/s12079-017-0393-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 05/09/2017] [Indexed: 12/14/2022] Open
Abstract
Perivascular fat, the cushion of adipose tissue surrounding blood vessels, possesses dilator, anti-contractile and constrictor actions. The majority of these effects have been demonstrated in vitro and may depend on the vessel and/or the experimental method or species used. In general, the relaxant effect of perivascular adipose tissue is local and may be either endothelium-dependent or endothelium-independent. However, nerve stimulation studies show that, in general, perivascular adipose tissue (PVAT) has an anti-contractile vascular effect likely to involve an action of the autonomic vascular nerves. Apart from a direct effect of perivascular fat-derived factors on bypass conduits, an interaction with a number of neurotransmitters and other agents may play an important role in graft performance. Although the vascular effects of PVAT are now well-established there is a lack of information regarding the role and/or involvement of peripheral nerves including autonomic nerves. For example, are perivascular adipocytes innervated and does PVAT affect neuronal control of vessels used as grafts? To date there is a paucity of electrophysiological studies into nerve-perivascular fat control. This review provides an overview of the vascular actions of PVAT, focussing on its potential relevance on blood vessels used as bypass grafts. In particular, the anatomical relationship between the perivascular nerves and fat are considered and the role of the perivascular-nerve/fat axis in the performance of bypass grafts is also discussed.
Collapse
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, NW3 2PF, London, 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, NW3 2PF, London, UK
| |
Collapse
|
22
|
Fernández-Alfonso MS, Gil-Ortega M, Aranguez I, Souza D, Dreifaldt M, Somoza B, Dashwood MR. Role of PVAT in coronary atherosclerosis and vein graft patency: friend or foe? Br J Pharmacol 2017; 174:3561-3572. [PMID: 28150299 DOI: 10.1111/bph.13734] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 01/02/2017] [Accepted: 01/19/2017] [Indexed: 01/18/2023] Open
Abstract
Perivascular adipose tissue (PVAT) releases numerous factors and adipokines with paracrine effects on both vascular structure and function. These effects are variable as they depend on regional differences in PVAT among blood vessels and vary with changes in adiposity. There is considerable evidence demonstrating an association between coronary PVAT and the development and progression of coronary artery disease, which is associated with inflammation, oxidative stress, angiogenesis, vascular remodelling and blood clotting. However, PVAT also has a protective role in vascular grafts, especially the no-touch saphenous vein, in patients undergoing coronary artery bypass. This beneficial influence of PVAT involves factors such as adipocyte-derived relaxing factor, nitric oxide (NO), leptin, adiponectin, prostanoids, hydrogen sulphide and neurotransmitters, as well as mechanical protection. This article aims to highlight and compare the dual role of PVAT in the development and progression of coronary atherosclerosis, as well as in increased graft patency. Different deleterious and protective mechanisms of PVAT are also discussed and the inside-outside signalling paradigm of atherosclerosis development re-evaluated. The bidirectional communication between the arterial and venous wall and their surrounding PVAT, where signals originating from the vascular wall or lumen can affect PVAT phenotype, has been shown to be very complex. Moreover, signals from PVAT also influence the structure and function of the vascular wall in a paracrine manner. LINKED ARTICLES This article is part of a themed section on Molecular Mechanisms Regulating Perivascular Adipose Tissue - Potential Pharmacological Targets? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.20/issuetoc.
Collapse
Affiliation(s)
- M S Fernández-Alfonso
- Instituto Pluridisciplinar and Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - M Gil-Ortega
- Departamento de Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad CEU-San Pablo, Madrid, Spain
| | - I Aranguez
- Instituto Pluridisciplinar and Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - D Souza
- Department of Cardiothoracic and Vascular Surgery and University Health Care Research Center, School of Medical Sciences, Örebro University, Örebro, Sweden
| | - M Dreifaldt
- Department of Cardiothoracic and Vascular Surgery and University Health Care Research Center, School of Medical Sciences, Örebro University, Örebro, Sweden
| | - B Somoza
- Departamento de Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad CEU-San Pablo, Madrid, Spain
| | - M R Dashwood
- Royal Free Hospital Campus, University College Medical School, London, UK
| |
Collapse
|
23
|
Lohsiriwat V, Scholefield JH, Wilson VG, Dashwood MR. Endothelin-1 and its receptors on haemorrhoidal tissue: a potential site for therapeutic intervention. Br J Pharmacol 2017; 174:569-579. [PMID: 28095606 DOI: 10.1111/bph.13719] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 06/15/2016] [Accepted: 07/10/2016] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE Haemorrhoids is a common anorectal condition affecting millions worldwide. We have studied the effect of endothelin-1 (ET-1) and the role of endothelin ETA and ETB receptors in haemorrhoid tissue. EXPERIMENTAL APPROACH Protein expression of ET-1, ETA and ETB receptors were compared between haemorrhoids and normal rectal submucosa using Western blot analysis, with the localization of proteins determined by autoradiography and immunohistochemistry. Effects of ET-1 and sarafotoxin 6a on human colonic and rectal arteries and veins was assessed by wire myography and the involvement of receptor subtypes established by selective antagonists. KEY RESULTS Dense binding of [125 I]-ET-1 to haemorrhoidal sections was reduced by selective receptor antagonists. A higher density of ETB than ETA receptors was found in haemorrhoidal, than in control rectal tissue and confirmed by Western blot analysis. ETA and ETB receptors were localized to smooth muscle of haemorrhoidal arteries and veins, with ETB receptors on the endothelium. Human colonic and rectal arteries and veins were similarly sensitive to ET-1 and affected by the ETA selective antagonist, but sarafotoxin S6a-induced contractions were more pronounced in veins and antagonized by a selective ETB receptor antagonist. CONCLUSIONS AND IMPLICATIONS ETA and ETB receptors are present in human haemorrhoids with ETB receptors predominating. ETA receptors are activated by ET-1 to mediate a contraction in arteries and veins, but the latter are selectively activated by sarafotoxin S6a - a response that involves ETB receptors at low concentrations. Selective ETB agonists may have therapeutic potential to reduce congestion of the haemorrhoidal venous sinusoids.
Collapse
Affiliation(s)
- Varut Lohsiriwat
- Division of Gastrointestinal Surgery, Queen's Medical Centre, University of Nottingham, Nottingham, UK
| | - John H Scholefield
- Division of Gastrointestinal Surgery, Queen's Medical Centre, University of Nottingham, Nottingham, UK
| | - Vincent G Wilson
- School of Life Sciences, Faculty of Medicine and Health Sciences, University of Nottingham, Nottingham, UK
| | - Michael R Dashwood
- Royal Free Hospital Campus, University College Medical School, London, UK
| |
Collapse
|
24
|
Leão SC, Dashwood MR, Andrade MSD, Santos NN, Teles ORLL, Souza WBD, Rodrigues TMDA. Analysis of immunostaining and western blotting of endothelin 1 and its receptors in mitral stenosis. Braz J Cardiovasc Surg 2016; 30:211-8. [PMID: 26107453 PMCID: PMC4462967 DOI: 10.5935/1678-9741.20150004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 01/26/2015] [Indexed: 11/20/2022] Open
Abstract
INTRODUCTION Rheumatic Fever represents a serious public health problem in developing countries, with thousands of new cases each year. It is an autoimmune disease, which occurs in response to infection by streptococcus A. OBJECTIVE The aim of this study was to evaluate the immunolabeling and protein expression for endothelin-1 and 3 (ET-1, ET-3) and its receptors (ETA, ETB) in rheumatic mitral valves. METHODS Immunohistochemistry was used to identify ET-1/ET-3 and ETA/ETB receptors in rheumatic and control mitral valves. Quantitative analysis of immunostaining for ET-1/ET-3 and ETA/ETB receptors was performed. In addition, western blot analysis was carried out to assess protein levels in tissue samples. RESULTS ET-1 and ETA receptor immunostaining predominated in stenotic valves, mainly associated with fibrotic regions, inflammatory areas and neovascularization. Quantitative analysis showed that the average area with positive expression of ET-1 was 18.21 ± 14.96%. For ETA and ETB, the mean expressed areas were respectively 15.06 ± 13.13% and 9.20 ± 11.09%. ET-3 did not have a significant expression. The correlation between the expression of both endothelin receptors were strongly positive (R = 0.74, P = 0.02), but the correlation between ET-1 and its receptor were negative for both ETA (R = -0.37, P = 0.25), and ETB (R = -0.14, P = 0.39). This data was supported by western blot analysis. CONCLUSION The strong correlation between ET-1 and its receptors suggests that both play a role in the pathophysiology of rheumatic mitral valve stenosis and may potentially act as biomarkers of this disease.
Collapse
Affiliation(s)
| | - Michael R Dashwood
- Department of Clinical Biochemistry, Medical School, University College London, London, UK
| | | | | | | | | | | |
Collapse
|
25
|
Affiliation(s)
- Michael R Dashwood
- Surgical and Interventional Sciences, Royal Free Hospital Campus, University College Medical School, Pond Street, London, NW3 2PF, UK.
| |
Collapse
|
26
|
Shen L, M. Evans I, Souza D, Dreifaldt M, R. Dashwood M, Vidya MA. Adiponectin: An Endothelium-Derived Vasoprotective Factor? Curr Vasc Pharmacol 2016; 14:168-74. [DOI: 10.2174/1570161114666151202210128] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 10/07/2015] [Accepted: 10/07/2015] [Indexed: 11/22/2022]
|
27
|
Dashwood MR, Loesch A. Inducible nitric oxide synthase and vein graft performance in patients undergoing coronary artery bypass surgery: physiological or pathophysiological role? Curr Vasc Pharmacol 2014; 12:144-51. [PMID: 22724466 DOI: 10.2174/157016111201140327164409] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 03/14/2012] [Accepted: 04/10/2012] [Indexed: 11/22/2022]
Abstract
Coronary artery disease is the major cause of mortalilty in the West with coronary artery bypass surgery (CABG) being a means of restoring blood supply to ischaemic myocardium. The long saphenous vein is the most commonly used bypass conduit but its patency is inferior to the internal thoracic artery, the 'gold standard' graft. In conventional procedures the saphenous vein is harvested in such a manner that considerable vascular damage is inflicted. The structures mainly affected by this vascular trauma are the endothelium, autonomic nerves and vascular smooth muscle all containing cells with the potential to release nitric oxide (NO). While the majority of studies into the potential role of NO in vein graft performance have focussed on the involvement of endothelial nitric oxide synthase (eNOS) less information is available regarding the role of the inducible isoform of nitric oxide synthase (iNOS). While the effects of eNOS-derived NO are principally beneficial, iNOS is generally associated with pathological conditions. While potential pathophysiological roles of iNOS are discussed in this review we also outline many studies suggesting that this isoenzyme plays an important role in maintaing vein graft patency in patients undergoing CABG, particularly when the saphenous vein is harvested with minimal surgical trauma.
Collapse
Affiliation(s)
| | - Andrzej Loesch
- Department of Clinical Biochemistry, Royal Free and University College Medical School, Pond Street, London NW3 2QG, UK.
| |
Collapse
|
28
|
Rayment SJ, Simpson JAD, Eames T, Acheson AG, Dashwood MR, Henry Y, Gruss H, Scholefield JH, Wilson VG. Dual effects of α2 -adrenoceptors in modulating myogenic tone in sheep isolated internal anal sphincter. Neurogastroenterol Motil 2014; 26:1095-103. [PMID: 24906134 DOI: 10.1111/nmo.12363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 04/17/2014] [Indexed: 02/08/2023]
Abstract
BACKGROUND The role of α-adrenoceptors in promoting continence through modulation of sphincter tone has focused primarily on the effects of α1 -adrenoceptors. We have used three clinically available agents, which are selective for α2 -adrenoceptors, to investigate their role in contractile and neurogenic responses on the internal anal sphincter (IAS). METHODS IAS strips, which had spontaneously generated tone, were used to investigate the contractile effect of lofexidine, brimonidine, and dexmedetomidine on muscle tone in the presence or absence of subtype selective antagonists. The effect of brimonidine on the magnitude and time course of neurogenic responses generated by electrical field stimulation (EFS) was also examined. The affinity of test compounds at α1 - and α2 -adrenoceptors was established by competition binding with [3H]-prazosin and [3H]-RX821002. KEY RESULTS All agonists caused concentration-dependent contraction of the IAS and lofexidine demonstrated an enantiomeric difference in potency with a 10-fold difference between the (-) and (+) isomers. Responses to lofexidine and dexmedetomidine were inhibited in the presence of the α1 -adrenoceptor selective antagonist prazosin, but not in the presence of RX811059 (α2 -adrenoceptor selective antagonist); brimonidine responses were inhibited by RX811059 and, to a lesser extent, by prazosin. Brimonidine affected both magnitude and duration of neurogenic responses, which was reversed in the presence of RX811059. CONCLUSIONS & INFERENCES We conclude that α2 -adrenoceptors can mediate contraction of IAS, although this effect is most evident with efficacious imidazoline agonists rather than the most selective ligand. In addition, this receptor subtype can directly inhibit noradrenergic contractile responses to EFS and, indirectly, enhance nitrergic relaxatory responses.
Collapse
Affiliation(s)
- S J Rayment
- Division of GI Surgery, School of Medicine, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Rodrigues TM, Leao SC, Andrade MS, Souza WB, Santos NN, Teles OR, Aragao CA, Sena M, Silva SO, Dashwood MR. A potential role of endothelins in rheumatic mitral stenotic valves. Life Sci 2013. [DOI: 10.1016/j.lfs.2014.01.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
30
|
Dashwood MR, Tsui JC. Corrigendum to ‘No-touch’ saphenous vein harvesting improves graft performance in patients undergoing coronary artery bypass surgery: A journey from bedside to bench [Vascular Pharmacology 58/3 (2013) 240–250]. Vascul Pharmacol 2013. [DOI: 10.1016/j.vph.2013.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
31
|
Haque SU, Dashwood MR, Heetun M, Shiwen X, Farooqui N, Ramesh B, Welch H, Savage FJ, Ogunbiyi O, Abraham DJ, Loizidou M. Efficacy of the specific endothelin a receptor antagonist zibotentan (ZD4054) in colorectal cancer: a preclinical study. Mol Cancer Ther 2013; 12:1556-67. [PMID: 23723122 DOI: 10.1158/1535-7163.mct-12-0975] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Endothelin 1 (ET-1) is overexpressed in cancer, contributing to disease progression. We previously showed that ET-1 stimulated proliferative, migratory, and contractile tumorigenic effects via the ET(A) receptor. Here, for the first time, we evaluate zibotentan, a specific ET(A) receptor antagonist, in the setting of colorectal cancer, in cellular models. Pharmacologic characteristics were further determined in patient tissues. Colorectal cancer lines (n = 4) and fibroblast strains (n = 6), isolated from uninvolved areas of colorectal cancer specimens, were exposed to ET-1 and/or ET(A)/(B) receptor antagonists. Proliferation (methylene blue), migration (scratch wounds), and contraction (gel lattices) were assessed. Receptor distribution and binding characteristics (K(d), B(max)) were determined using autoradiography on tissue sections and homogenates and cytospun cells, supported by immunohistochemistry. Proliferation was inhibited by ET(A) (zibotentan > BQ123; P < 0.05), migration by ET(B) > ET(A), and contraction by combined ET(A) and ET(B) antagonism. Intense ET-1 stromal binding correlated with fibroblasts and endothelial cells. Colorectal cancer lines and fibroblasts revealed high density and affinity ET-1 binding (B(max) = 2.435 fmol/1 × 10(6) cells, K(d) = 367.7 pmol/L; B(max) = 3.03 fmol/1 × 10(6) cells, K(d) = 213.6 pmol/L). In cancer tissues, ET(A) receptor antagonists (zibotentan; BQ123) reduced ET-1 binding more effectively (IC(50): 0.1-10 μmol/L) than ET(B) receptor antagonist BQ788 (∼IC(50), 1 mmol/L). ET-1 stimulated cancer-contributory processes. Its localization to tumor stroma, with greatest binding/affinity to fibroblasts, implicates these cells in tumor progression. ET(A) receptor upregulation in cancer tissues and its role in tumorigenic processes show the receptor's importance in therapeutic targeting. Zibotentan, the most specific ET(A) receptor antagonist available, showed the greatest inhibition of ET-1 binding. With its known safety profile, we provide evidence for zibotentan's potential role as adjuvant therapy in colorectal cancer.
Collapse
Affiliation(s)
- Samer-ul Haque
- Cancer Nanotechnology Group, UCL Division of Surgery and Interventional Science, Royal Free Hospital, UK
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
|
33
|
Loesch A, Dashwood MR, Coppi AA. Immunoreactive Endothelin-1 and Endothelin A Receptor in Basilar Artery Perivascular Nerves of Young and Adult Capybaras. Cells Tissues Organs 2013; 198:47-56. [DOI: 10.1159/000348617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/04/2013] [Indexed: 11/19/2022] Open
|
34
|
Wang R, Löhr CV, Fischer K, Dashwood WM, Greenwood JA, Ho E, Williams DE, Ashktorab H, Dashwood MR, Dashwood RH. Epigenetic inactivation of endothelin-2 and endothelin-3 in colon cancer. Int J Cancer 2012; 132:1004-12. [PMID: 22865632 DOI: 10.1002/ijc.27762] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 07/18/2012] [Indexed: 12/16/2022]
Abstract
Endothelin-1 (ET-1) and its receptors are overexpressed in human cancers, but much less is known about the roles of ET-2 and ET-3 in cancer etiology. We sought to examine human and rat colon tumors for dysregulation of ET-2 and ET-3 expression and determine the underlying mechanisms. Human primary colon cancers and carcinogen-induced rat colon tumors were subjected to real-time RT-PCR, immunoblotting and immunohistochemistry; EDN2 and EDN3 genes were examined by methylation-specific PCR, bisulfite sequencing and pyrosequencing; and forced expression of ET-2 and ET-3 was conducted in human colon cancer cells followed by real-time cell migration and invasion assays. Rat and human colon tumors had markedly reduced expression of ET-2 and ET-3 mRNA and protein compared with matched controls. Mechanistic studies revealed hypermethylation of EDN2 and EDN3 genes in human primary colon cancers and in a panel of human colon cancer cell lines. Forced expression of ET-2 and ET-3 attenuated significantly the migration and invasion of human colon cancer cells. We conclude that epigenetic inactivation of ET-2 and ET-3 occurs frequently in both rat and human colon cancers. Current therapeutic strategies target overexpressed members of the ET axis via small molecule inhibitors and receptor antagonists, but this work supports a complementary approach based on the re-expression of ET-2 and ET-3 as natural antagonists of ET-1 in colon cancer.
Collapse
Affiliation(s)
- Rong Wang
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Dashwood MR, Tsui JC. 'No-touch' saphenous vein harvesting improves graft performance in patients undergoing coronary artery bypass surgery: a journey from bedside to bench. Vascul Pharmacol 2012; 58:240-50. [PMID: 22967905 DOI: 10.1016/j.vph.2012.07.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 07/14/2012] [Accepted: 07/31/2012] [Indexed: 11/19/2022]
Abstract
The saphenous vein is the most commonly used conduit in patients undergoing coronary artery bypass surgery yet its patency is inferior to the internal thoracic artery. Vascular damage inflicted to the vein when using conventional harvesting techniques affects its structure. Endothelial denudation is associated with early vein graft failure while damage of the outermost vessel layers has adverse long-term effects on graft performance. While many in vitro and in vivo experimental studies aimed at improving vein graft patency have been performed to date no significant 'bench to bedside' advances have been made. Among experimental strategies employed is the use of pharmacological agents, gene targeting and external stents. A 'no-touch' technique, where the saphenous vein is removed with minimal trauma and normal architecture preserved, produces a superior graft with long term patency comparable to the internal thoracic artery. Interestingly, many experimental studies are aimed at repairing or replacing those regions of the saphenous vein damaged when harvesting conventionally. 'No-touch' harvesting is superior in coronary artery bypass patients with long-term data published 5years ago. Here we describe a 'bedside to bench' situation where the mechanisms underlying the improved performance of 'no touch' saphenous vein grafts in patients have been studied in the laboratory.
Collapse
Affiliation(s)
- Michael R Dashwood
- Department of Clinical Biochemistry, Royal Free and University College Medical School, Pond Street, London NW3 2QG, United Kingdom.
| | | |
Collapse
|
36
|
Dashwood MR, Crump A, Shi-Wen X, Loesch A. Identification of neuronal nitric oxide synthase (nNOS) in human penis: a potential role of reduced neuronally-derived nitric oxide in erectile dysfunction. Curr Pharm Biotechnol 2012; 12:1316-21. [PMID: 21506911 DOI: 10.2174/138920111798280965] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 06/29/2010] [Accepted: 07/01/2010] [Indexed: 11/22/2022]
Abstract
Erectile dysfunction (ED) commonly occurs in approximately 15% of men over 70 years old. A number of causes of this condition are recognised with the major mechanism of ED being an impaired relaxation of the corpus cavernosum (CC) smooth muscle and resulting reduction in penile blood flow. There are reports that ED is associated with a reduction in local levels of endothelium-derived nitric oxide (NO) with most studies focussing on the potential role of endothelial nitric oxide synthase (eNOS) in the erectile process. Since there is a recognised neurogenic component of ED we have studied altered nerve density and neuronal nitric oxide synthase (nNOS) distribution by immunohistochemistry and nNOS protein expression by western blot analysis in penises from patients with neurogenic ED and diabetes compared with control tissue obtained from patients undergoing gender reassignment. There was a significant reduction in nerve density in tissue from ED compared with control patients (P < 0.05). Immunostaining for nNOS colocalised with nerves and was reduced in ED tissue, as were nNOS protein levels. We have shown that nerve degeneration observed in penile tissue from ED patients is accompanied by a decrease in nNOS suggesting that reduced neuronal- as well as endothelium-derived NO plays a role in this condition.
Collapse
Affiliation(s)
- Michael R Dashwood
- Clinical Biochemistry, Royal Free and University College Medical School, Royal Free Campus, Pond Street, London NW3 2QG, United Kingdom.
| | | | | | | |
Collapse
|
37
|
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: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
Affiliation(s)
- Mats Dreifaldt
- Department of Thoracic and Cardiovascular Surgery, Örebro University Hospital, Sweden
| | | | | | | | | | | | | | | |
Collapse
|
38
|
|
39
|
Dashwood MR, Loizidou M. Determination of cell-specific receptor binding using a combination of immunohistochemistry and in vitro autoradiography: relevance to therapeutic receptor targeting in cancer. Methods Mol Biol 2012; 878:137-47. [PMID: 22674131 DOI: 10.1007/978-1-61779-854-2_9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Mapping of receptor binding to specific structures, or cells within tissue samples, provides valuable information regarding biological and pathological mechanisms. Such information may potentially be translated into targeted therapies, especially in the field of cancer treatment. In this chapter, a receptor localization technique is described which utilises frozen sections of human tissue and combines immunohistochemistry (IHC) and micro-autoradiography. IHC utilises antibodies tagged to an enzymatic complex to identify specific cell types (such as epithelial cells or fibroblasts) within the tissue under investigation; this step is immediately followed by the second technique which is based on the use of radiolabelled compounds (radioligands) that selectively bind to preselected membrane receptors. This approach allows visualisation of cells of interest by immunohistochemical staining of tissue sections (colour product) in combination with the use of radiolabelled compounds that are detected following exposure to radiation-sensitive film or emulsion to produce a map of receptor distribution or localisation of cell-specific receptor binding. The system described has been used to compare receptor binding to cells in normal human colorectal tissue with that in colorectal cancer specimens.
Collapse
Affiliation(s)
- Michael R Dashwood
- Department of Clinical Biochemistry, Royal Free and UCL Medical School, London, UK.
| | | |
Collapse
|
40
|
Knowles JP, Shi-Wen X, Haque SU, Bhalla A, Dashwood MR, Yang S, Taylor I, Winslet MC, Abraham DJ, Loizidou M. Endothelin-1 stimulates colon cancer adjacent fibroblasts. Int J Cancer 2011; 130:1264-72. [PMID: 21445967 DOI: 10.1002/ijc.26090] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Accepted: 02/08/2011] [Indexed: 12/25/2022]
Abstract
Endothelin-1 (ET-1) is produced by and stimulates colorectal cancer cells. Fibroblasts produce tumour stroma required for cancer development. We investigated whether ET-1 stimulated processes involved in tumour stroma production by colonic fibroblasts. Primary human fibroblasts, isolated from normal tissues adjacent to colon cancers, were cultured with or without ET-1 and its antagonists. Cellular proliferation, migration and contraction were measured. Expression of enzymes involved in tumour stroma development and alterations in gene transcription were determined by Western blotting and genome microarrays. ET-1 stimulated proliferation, contraction and migration (p < 0.01 v control) and the expression of matrix degrading enzymes TIMP-1 and MMP-2, but not MMP-3. ET-1 upregulated genes for profibrotic growth factors and receptors, signalling molecules, actin modulators and extracellular matrix components. ET-1 stimulated colonic fibroblast cellular processes in vitro that are involved in developing tumour stroma. Upregulated genes were consistent with these processes. By acting as a strong stimulus for tumour stroma creation, ET-1 is proposed as a target for adjuvant cancer therapy.
Collapse
Affiliation(s)
- Jonathan P Knowles
- Department of Surgery, UCL Division of Surgery and Interventional Science, London, United Kingdom
| | | | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Lohsiriwat V, Scholefield JH, Dashwood MR, Wilson VG. Pharmacological characteristics of endothelin receptors on sheep rectal blood vessels. Pharmacol Res 2011; 63:490-5. [PMID: 21382493 DOI: 10.1016/j.phrs.2011.02.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Revised: 02/25/2011] [Accepted: 02/27/2011] [Indexed: 12/23/2022]
Abstract
Haemorrhoids is associated with high blood flow of the anorectal region. The question of whether pharmacological manipulation of vascular supply can relieve the symptoms of haemorrhoids has been raised. In order to undertake this type of clinical investigation, it is first essential to gain a better understanding of the properties of vascular receptors that may regulate blood flow into anal cushions and haemorrhoids. Due to the limited availability of human anorectal specimens and the good reliability of sheep tissue as an experimental model of human anorectal diseases, we studied the properties of endothelin receptors in sheep rectal artery (SRA) and vein (SRV), the vessels contributing to the blood flow of haemorrhoidal plexus, using isometric tension recordings. We found that endothelin-1 and sarafotoxin 6a were very potent constrictor agents in both SRA and SRV. The selective ET(A) receptor antagonist PD156707 (100 nM) produced a parallel rightward displacement of ET-1-induced contractions in both vessels and abolished sarafotoxin 6a-induced contractions in the SRA. PD156707 (3 μM) practically abolished contractions to ET-1 in the SRA, suggesting that the response is entirely mediated by ET(A) receptors. While, the selective ET(B) receptor antagonist BQ788 (100 nM) caused no significant change in ET-1-induced contractions in both vessels, a minor role for ET(B) receptor subtype to responses to sarafotoxin 6a in the artery was suggested.
Collapse
Affiliation(s)
- Varut Lohsiriwat
- Division of Gastrointestinal Surgery, Queen's Medical Centre, University of Nottingham, UK.
| | | | | | | |
Collapse
|
42
|
Rayment SJ, Eames T, Simpson JAD, Dashwood MR, Henry Y, Gruss H, Acheson AG, Scholefield JH, Wilson VG. Investigation of the distribution and function of alpha-adrenoceptors in the sheep isolated internal anal sphincter. Br J Pharmacol 2010; 160:1727-40. [PMID: 20649575 DOI: 10.1111/j.1476-5381.2010.00842.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE We have investigated the distribution of alpha-adrenoceptors in sheep internal anal sphincter (IAS), as a model for the human tissue, and evaluated various imidazoline derivatives for potential treatment of faecal incontinence. EXPERIMENTAL APPROACH Saturation and competition binding with (3)H-prazosin and (3)H-RX821002 were used to confirm the presence and density of alpha-adrenoceptors in sheep IAS, and the affinity of imidazoline compounds at these receptors. A combination of in vitro receptor autoradiography and immunohistochemistry was used to investigate the regional distribution of binding sites. Contractile activity of imidazoline-based compounds on sheep IAS was assessed by isometric tension recording. KEY RESULTS Saturation binding confirmed the presence of both alpha(1)- and alpha(2)-adrenoceptors, and subsequent characterization with sub-type-selective agents, identified them as alpha(1A)- and alpha(2D)-adrenoceptor sub-types. Autoradiographic studies with (3)H-prazosin showed a positive association of alpha(1)-adrenoceptors with immunohistochemically identified smooth muscle fibres. Anti-alpha(1)-adrenoceptor immunohistochemistry revealed similar distributions of the receptor in sheep and human IAS. The imidazoline compounds caused concentration-dependent contractions of the anal sphincter, but the maximum responses were less than those elicited by l-erythro-methoxamine, a standard non-imidazoline alpha(1)-adrenoceptor agonist. Prazosin (selective alpha(1)-adrenoceptor antagonist) significantly reduced the magnitude of contraction to l-erythro-methoxamine at the highest concentration used. Both prazosin and RX811059 (a selective alpha(2)-adrenoceptor antagonist) reduced the potency (pEC(50)) of clonidine. CONCLUSIONS AND IMPLICATIONS This study shows that both alpha(1)- and alpha(2)-adrenoceptors are expressed in the sheep IAS, and contribute (perhaps synergistically) to contractions elicited by various imidazoline derivatives. These agents may prove useful in the treatment of faecal incontinence.
Collapse
Affiliation(s)
- S J Rayment
- Centre for Integrated Systems Biology and Medicine, Department of Surgery, The University of Nottingham Medical School, Queen's Medical Centre, Clifton Boulevard, Nottingham, UK
| | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Dashwood MR, Dooley A, Shi-Wen X, Abraham DJ, Dreifaldt M, Souza DSR. Perivascular fat-derived leptin: a potential role in improved vein graft performance in coronary artery bypass surgery. Interact Cardiovasc Thorac Surg 2010; 12:170-3. [PMID: 21051379 DOI: 10.1510/icvts.2010.247874] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Perivascular tissue (PVT) surrounding many blood vessels, including those used as bypass conduits, is the source of adipocyte-derived relaxing factors, one of which is leptin. Here, we assessed leptin levels and identified leptin localization in the cushion of fat surrounding 'no-touch-harvested' saphenous veins (SVs) used as grafts in 15 patients undergoing coronary artery bypass surgery (CABG). Leptin protein was identified in perivascular fat (PVF) extracts by Western blot analysis and leptin levels were 2.2 (0.5-4.2) ng/mg protein [mean (range), n=10] as assessed by ELISA. There was dense leptin immunostaining of fat and adipocyte membranes surrounding these no-touch SV grafts. PVT-derived factors are suggested to play an important role in the superior patency rate of the internal thoracic artery used as a bypass graft. Our findings suggest that, as a potent vasodilator, PVF-derived leptin may also play an important role both at harvesting and in the improved long-term performance of no-touch SVs in patients undergoing CABG.
Collapse
Affiliation(s)
- Michael R Dashwood
- Department of Clinical Biochemistry, Royal Free and University College Medical School, Pond Street, London NW3 2QG, UK.
| | | | | | | | | | | |
Collapse
|
44
|
Dreifaldt M, Souza DSR, Loesch A, Muddle JR, Karlsson MG, Filbey D, Bodin L, Norgren L, Dashwood MR. The "no-touch" harvesting technique for vein grafts in coronary artery bypass surgery preserves an intact vasa vasorum. J Thorac Cardiovasc Surg 2010; 141:145-50. [PMID: 20381817 DOI: 10.1016/j.jtcvs.2010.02.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Revised: 12/15/2009] [Accepted: 02/01/2010] [Indexed: 11/16/2022]
Abstract
OBJECTIVES Our objective was to evaluate the impact of vein graft harvesting technique on structure and function of vasa vasorum. METHODS Paired segments of great saphenous veins harvested either with conventional harvesting technique or no-touch technique were obtained from 9 consecutive patients undergoing coronary artery bypass grafting. Quantitative measurements, using immunohistochemistry and morphometry, were performed. Ultrastructural analyses of vasa vasorum were performed with electron microscopy. Video footage of superficial vasa vasorum in an implanted saphenous vein graft harvested with the no-touch technique was captured during a coronary bypass operation and is presented for online viewing. RESULTS The total area of vasa vasorum in vein grafts harvested with the conventional technique was significantly reduced both in the media (P = .007) and in the adventitia (P = .014) compared with vein grafts harvested with the no-touch technique. Ultrastructural findings indicated that the no-touch technique preserved an intact vasa vasorum whereas the conventional technique did not. Video footage showed retrograde flow in the vasa vasorum in vein graft harvested with the no-touch technique. CONCLUSIONS These findings show that the no-touch technique for saphenous vein graft harvesting for coronary bypass grafting preserves an intact vasa vasorum. This could represent one of the mechanisms underlying the improved patency of saphenous vein grafts harvested with this technique.
Collapse
Affiliation(s)
- Mats Dreifaldt
- Department of Thoracic and Cardiovascular Surgery, Örebro University Hospital, Örebro, Sweden.
| | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Dashwood MR, Fremes S, Souza DS. Saphenous vein harvest with the Mayo extraluminal dissector: Is endothelial function preserved? J Thorac Cardiovasc Surg 2010; 139:239-41; author reply 241. [DOI: 10.1016/j.jtcvs.2009.08.054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 08/17/2009] [Indexed: 11/16/2022]
|
46
|
Dashwood MR, Timm M, Kaski JC, Murdayz AJ, Madden BP. [125I]-ET=1 Binding to Perivascular Nerves of Human Epicardial Coronary Arteries. ACTA ACUST UNITED AC 2009. [DOI: 10.3109/10623329609024699] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
47
|
Abstract
The saphenous vein is the most commonly used graft for revascularization procedures in patients with coronary artery disease and critical limb ischaemia. However, the patency rate of this vessel is poor, with a high proportion of patients requiring further surgery. Early graft occlusion is caused by vasoconstriction or thrombus formation, with later stages of graft failure being due to neointimal formation or atherosclerosis. Apart from its potent constrictor action, endothelin-1 is also a potent proliferative and proinflammatory peptide that is implicated in a number of vascular diseases. The surgical trauma caused during preparation of the saphenous vein as a bypass graft stimulates the release of a number of factors affecting vascular reactivity and structure, including endothelin-1. Endothelin-1 not only constricts animal and human isolated saphenous vein segments but also causes vascular smooth muscle proliferation and neointimal thickening in vitro, actions that are mediated via endothelin (A and B) receptors. Experimentally, the effects of subtype-selective and dual receptor antagonists have been shown to inhibit endothelin-1-mediated constriction and cell proliferation of the saphenous vein. In this review, data supporting a role of endothelin-1 in vein graft occlusion are presented, and the therapeutic potential of endothelin receptor antagonists in improving graft performance is discussed.
Collapse
Affiliation(s)
- M R Dashwood
- Royal Free and University College Medical School, London, UK.
| |
Collapse
|
48
|
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: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
Affiliation(s)
- Michael R Dashwood
- Department of Clinical Biochemistry, Royal Free and University College Medical School, Royal Free Campus, Pond Street, London, United Kingdom.
| | | | | | | | | | | | | | | |
Collapse
|
49
|
Abstract
Alterations in nitric oxide synthase (NOS) are implicated in ischemia and ischemia-reperfusion injury. Changes in the 3 NOS isoforms in human skeletal muscle subjected to acute ischemia and reperfusion were studied. Muscle biopsies were taken from patients undergoing total knee replacement. Distribution of the specific NOS isoforms within muscle sections was studied using immunohistochemistry. NOS mRNA levels were measured using real-time reverse transcription-polymerase chain reaction and protein levels studied using Western blotting. NOS activity was also assessed using the citrulline assay. All 3 NOS isoforms were found in muscle sections associated with muscle fibers and microvessels. In muscle subjected to acute ischemia and reperfusion, NOS I/neuronal NOS mRNA and protein were elevated during reperfusion. NOS III/endothelial NOS was also upregulated at the protein level during reperfusion. No changes in NOS II/inducible NOS expression or NOS activity occurred. In conclusion, alterations in NOS I and III (neuronal NOS and endothelial NOS) at different levels occurred after acute ischemia and reperfusion in human skeletal muscle; however, this did not result in increased NOS activity. In the development of therapeutic agents based on manipulation of the NO pathway, targeting the appropriate NOS isoenzymes may be important.
Collapse
|
50
|
Tsui JCS, Baker DM, Shaw SG, Shi-Wen X, Dashwood MR. Nitric oxide synthase in critically ischaemic muscle and alterations in isoform expression during revascularization surgery. Br J Surg 2007; 95:72-9. [PMID: 17849374 DOI: 10.1002/bjs.5910] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Dysfunction of the nitric oxide pathway is implicated in peripheral arterial disease. Nitric oxide synthase (NOS) isoforms and NOS activity were studied in muscle from patients with critical leg ischaemia (CLI). Alterations in NOS during revascularization surgery were also assessed. METHODS Muscle biopsies were taken from patients with CLI undergoing amputation and also from patients undergoing femorodistal bypass at the start of surgery, after arterial clamping and following reperfusion. The presence of NOS within muscle sections was confirmed using reduced nicotinamide adenine dinucleotide phosphate diaphorase histochemistry. NOS isoform distribution was studied by immunohistochemistry. NOS mRNA and protein levels were measured using real-time reverse transcriptase-polymerase chain reaction and western blotting. NOS activity was assessed with the citrulline assay. RESULTS All three NOS isoforms were found in muscle, associated with muscle fibres and microvessels. NOS I and III protein expression was increased in CLI (P = 0.041). During revascularization, further ischaemia and reperfusion led to a rise in NOS III protein levels (P = 0.008). NOS activity was unchanged. CONCLUSION Alterations in NOS I and III occurred in muscle from patients with CLI and further changes occurred during bypass surgery.
Collapse
Affiliation(s)
- J C S Tsui
- Department of Surgery, Royal Free and University College Medical School, London, UK.
| | | | | | | | | |
Collapse
|