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Ribas LM, Torres IO, Appolonio F, Rosa KPD, do Espírito-Santo FRF, De Luccia N. Experimental implantation of an arterial substitute made of silicone reinforced with polyester fabric in rabbits. Clinics (Sao Paulo) 2017; 72:780-784. [PMID: 29319725 PMCID: PMC5738571 DOI: 10.6061/clinics/2017(12)10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 08/04/2017] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES The aim of this study was to analyze silicone tubes with an internal diameter of 4 mm as a possible material for vascular prostheses. METHODS Grafts were implanted into the infrarenal aortas of 33 rabbits. Fluoroscopic examinations were performed within 150 days after surgical implantation. Sample grafts were analyzed via electron microscopy to evaluate the eventual endothelialization of the prostheses. RESULTS The patency rates of the prostheses were 87% (±6.7%) after 30 days, 73% (±9.3%) after 60 days and 48% (±12%) after 120 days. The material presented characteristics that support surgical implantation: good tolerance promoted by polyester tear reinforcement, ease of postoperative removal and a lack of pseudoaneurysms. However, intimal hyperplasia was a limiting factor for the patency rate. CONCLUSIONS We concluded that polydimethylsiloxane has limited potential as an alternative material for small vascular prostheses.
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Affiliation(s)
- Laila Massad Ribas
- Departamento de Cirurgia, Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, BR
- *Corresponding author. E-mail:
| | - Inez Ohashi Torres
- Departamento de Cirurgia, Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, BR
| | - Fernanda Appolonio
- Departamento de Cirurgia, Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, BR
| | | | | | - Nelson De Luccia
- Departamento de Cirurgia, Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, BR
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2
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Sukhovershin RA, Yepuri G, Ghebremariam YT. Endothelium-Derived Nitric Oxide as an Antiatherogenic Mechanism: Implications for Therapy. Methodist Debakey Cardiovasc J 2016; 11:166-71. [PMID: 26634024 DOI: 10.14797/mdcj-11-3-166] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Endothelium-derived nitric oxide (eNO) is a multifunctional signaling molecule critically involved in the maintenance of metabolic and cardiovascular homeostasis. In addition to its role as a potent endogenous vasodilator, eNO suppresses key processes in vascular lesion formation and opposes atherogenesis. This review discusses eNO as an antiatherogenic molecule and highlights factors that influence its bioavailability and therapeutic approaches to restore or enhance its levels.
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Affiliation(s)
- Roman A Sukhovershin
- Houston Methodist DeBakey Heart & Vascular Center, Houston Methodist Hospital, Houston, Texas
| | - Gautham Yepuri
- Houston Methodist DeBakey Heart & Vascular Center, Houston Methodist Hospital, Houston, Texas
| | - Yohannes T Ghebremariam
- Houston Methodist DeBakey Heart & Vascular Center, Houston Methodist Hospital, Houston, Texas
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3
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Wan J, Lata C, Santilli A, Green D, Roy S, Santilli S. Supplemental oxygen reverses hypoxia-induced smooth muscle cell proliferation by modulating HIF-alpha and VEGF levels in a rabbit arteriovenous fistula model. Ann Vasc Surg 2014; 28:725-36. [PMID: 24345704 PMCID: PMC3968233 DOI: 10.1016/j.avsg.2013.10.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 10/30/2013] [Accepted: 10/31/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND Numerous mechanisms for the formation of intimal hyperplasia have been proposed but none have been proven or accepted. Our research focuses on the potential role of hypoxia-inducible factors (HIFs), vascular endothelial growth factor (VEGF), and platelet-derived growth factors as well as the extracellular signal-regulated kinase (ERK), phosphatidylinositide 3-kinase /protein Kinase B (PI3-K/AKT) pathway in hypoxia-mediated intimal hyperplasia processes. We hypothesize that HIF and VEGF will be downregulated with supplemental oxygen in our arteriovenous fistula rabbit model. METHODS Rabbits were randomized into different experimental groups with varying oxygen exposure (21% O2 or 30% O2) and receipt of surgery (surgery with fistula formation, no surgery, or sham operation with skin incision only). Plasma samples were collected at designated intervals in which cytokines and smooth muscle cell proliferation were measured. In addition, cell specimens were exposed to hyperoxic, normoxic, and hypoxic environments with cytokines measured at various time points. RESULTS Placement of an arteriovenous fistula resulted in hypoxia-induced HIF stabilization with a concurrent increase in VEGF levels. There was a 4.2-fold induction in HIF-1α levels in animals that were placed in normal air after surgery when compared with animals that were exposed to hyperoxic air. Also, VEGF level significantly increased after surgery in the normoxic group, reaching a maximum of 959 pg/mL. Plasma VEGF levels in the surgery and supplemental oxygen group were significantly lower than the normoxic surgery group with almost a 45% reduction in plasma VEGF levels (524 pg/mL). Activation of VEGF receptors on smooth muscle cells through ERK1 and AKT pathways resulted in significant smooth muscle cell proliferation and migration. These effects are dramatically reduced in animals that are exposed to a hyperoxic environment of 30% oxygen. CONCLUSIONS Our results suggest that short-term administration of supplemental oxygen inhibits HIFs and VEGF signaling to reduce smooth muscle proliferation in the local blood vessel. These results provide strong support for the therapeutic use of supplemental oxygen after arterial surgery to reduce intimal hyperplasia. These findings also provide a nidus for future clinical trials to determine whether this is clinically applicable in humans.
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MESH Headings
- Animals
- Arteriovenous Shunt, Surgical/adverse effects
- Cell Movement
- Cell Proliferation
- Cells, Cultured
- Cytokines/metabolism
- Hyperplasia
- Hypoxia/metabolism
- Hypoxia/pathology
- Hypoxia-Inducible Factor 1, alpha Subunit/metabolism
- Iliac Artery/metabolism
- Iliac Artery/physiopathology
- Iliac Artery/surgery
- Iliac Vein/metabolism
- Iliac Vein/pathology
- Iliac Vein/surgery
- Male
- Mitogen-Activated Protein Kinase 3/metabolism
- Models, Animal
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/surgery
- Myocytes, Smooth Muscle/metabolism
- Myocytes, Smooth Muscle/pathology
- Neointima
- Oxygen Inhalation Therapy
- Phosphorylation
- Platelet-Derived Growth Factor/metabolism
- Proto-Oncogene Proteins c-akt/metabolism
- Rabbits
- Signal Transduction
- Time Factors
- Vascular Endothelial Growth Factor A/metabolism
- Vascular Endothelial Growth Factor Receptor-2/metabolism
- Wound Healing
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Affiliation(s)
- Jing Wan
- Zhongnan Hospital Wuhan University, Wuhan, Hubei, China
| | - Charu Lata
- Division of Vascular Surgery, Department of Surgery, University of Minnesota and Minneapolis Veterans Health Care System, Minneapolis, MN
| | - Ashley Santilli
- Division of Vascular Surgery, Department of Surgery, University of Minnesota and Minneapolis Veterans Health Care System, Minneapolis, MN
| | - Derrick Green
- Division of Vascular Surgery, Department of Surgery, University of Minnesota and Minneapolis Veterans Health Care System, Minneapolis, MN
| | - Sabita Roy
- Division of Vascular Surgery, Department of Surgery, University of Minnesota and Minneapolis Veterans Health Care System, Minneapolis, MN
| | - Steven Santilli
- Division of Vascular Surgery, Department of Surgery, University of Minnesota and Minneapolis Veterans Health Care System, Minneapolis, MN.
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4
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Lata C, Green D, Wan J, Roy S, Santilli SM. The role of short-term oxygen administration in the prevention of intimal hyperplasia. J Vasc Surg 2013; 58:452-9. [PMID: 23380177 DOI: 10.1016/j.jvs.2012.11.041] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 10/30/2012] [Accepted: 11/03/2012] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Intimal hyperplasia (IH) is the cause of most failed arteriovenous fistulas (AVFs), resulting in repeat procedures and leading to increased utilization of scarce health care resources. Our laboratory has previously demonstrated the role of supplemental oxygen in preventing IH and smooth muscle cell proliferation (SMCp) at an artery-to-graft anastomosis and at the deployment site of an intra-arterial stent. This study examines the effect of supplemental oxygen in preventing IH and SMCp in an AVF in a rabbit model. METHODS Ninety-six rabbits were randomized into four groups: group 1, control; group 2, no surgery with supplemental oxygen; group 3, AVF without supplemental oxygen; and group 4, AVF with supplemental oxygen. Rabbits receiving supplemental oxygen received 30% oxygen for up to 42 days. Specimens were collected in all groups at days 1, 3, 7, 21, 42, and 90. IH and SMCp were measured at the AVF site as well as in the artery and vein proximal and distal to the AVF. RESULTS IH was first noted at day 7 and significantly increased through day 90 at all locations in the nonoxygen-supplemented groups. No significant IH was noted in the oxygen-supplemented group at any location or any time point. SMCp was noted at day 3 through day 21 in the nonoxygen-supplemented group, whereas almost no SMCp was noted in the oxygen-supplemented group at any location or time point. CONCLUSIONS Without oxygen supplementation, SMCp begins at day 3 and is no longer noted at day 21 after creation of an AVF, whereas IH begins by day 7 and increases at least through day 90 after creation of an AVF. Forty-two days of 30% supplemental oxygen inhibits IH and SCMp after creation of an AVF. These data suggest a role for the short-term administration of low-dose O2 to prevent both IH and SMCp after creation of an AVF that may prolong patency and function.
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MESH Headings
- Animals
- Arteriovenous Shunt, Surgical/adverse effects
- Cell Proliferation
- Graft Occlusion, Vascular/etiology
- Graft Occlusion, Vascular/pathology
- Graft Occlusion, Vascular/physiopathology
- Graft Occlusion, Vascular/prevention & control
- Hyperplasia
- Iliac Artery/drug effects
- Iliac Artery/pathology
- Iliac Artery/physiopathology
- Iliac Artery/surgery
- Iliac Vein/drug effects
- Iliac Vein/pathology
- Iliac Vein/physiopathology
- Iliac Vein/surgery
- Male
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/surgery
- Neointima
- Oxygen Inhalation Therapy
- Rabbits
- Time Factors
- Vascular Patency
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Affiliation(s)
- Charu Lata
- Department of Surgery, University of Minnesota and Minneapolis Veterans Health Care System, Minneapolis, MN 55455, USA
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5
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Abstract
Atherosclerosis is a chronic inflammatory process in the intima of conduit arteries, which disturbs the endothelium-dependent regulation of the vascular tone by the labile liposoluble radical nitric oxide (NO) formed by the constitutive endothelial nitric oxide synthase (eNOS). This defect predisposes to coronary vasospasm and cardiac ischaemia, with anginal pain as the typical clinical manifestation. It is now appreciated that endothelial dysfunction is an early event in atherogenesis and that it may also involve the microcirculation, in which atherosclerotic lesions do not develop. On the other hand, the inflammatory environment in atherosclerotic plaques may result in the expression of the inducible NO synthase (iNOS) isozyme. Whether the dysfunction in endothelial NO production is causal to, or the result of, atherosclerotic lesion formation is still highly debated. Most evidence supports the hypothesis that constitutive endothelial NO release protects against atherogenesis e.g. by preventing smooth muscle cell proliferation and leukocyte adhesion. Nitric oxide generated by the inducible isozyme may be beneficial by replacing the failing endothelial production but excessive release may damage the vascular wall cells, especially in combination with reactive oxygen intermediates.
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Affiliation(s)
- K E Matthys
- University of Antwerp (UIA) Division of Pharmacology Wilrijk Antwerp B2610 Belgium
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6
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Nigri GR, Kossodo S, Waterman P, Fungaloi P, LaMuraglia GM. Free radical attenuation prevents thrombosis and enables photochemical inhibition of vein graft intimal hyperplasia. J Vasc Surg 2004; 39:843-9. [PMID: 15071453 DOI: 10.1016/j.jvs.2003.11.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Photodynamic therapy (PDT) inhibits post-interventional stenosis in balloon-injured arteries, but causes thrombosis when applied to vein grafts. This may result from added free radicals produced during the hypoxia-reperfusion injury of vein graft implantation. The purposes of this study were to determine whether a free radical scavenger could inhibit vein graft thrombosis, enabling PDT to inhibit intimal hyperplasia; and to investigate the role of neutrophils, also a source of radicals, in this setting. METHODS Jugular vein bypass grafts of the common carotid artery were performed in rats. PDT was administered in situ to the vein graft and artery in the presence or absence of deferoxamine (DFX), an OH- scavenger. RESULTS PDT alone induced thrombosis in all untreated vein grafts. DFX administration or inhibition of neutrophil adhesion to the graft prevented PDT-induced vein graft thrombosis. Moreover, DFX given together with PDT significantly decreased vein graft intimal hyperplasia (0.010 mm2 +/- 0.005 mm2; P<.002) as compared with DFX alone (0.113 mm2 +/- 0.009 mm2) or untreated control animals (0.112 +/- 0.007 mm2). CONCLUSIONS OH- radicals and neutrophils both have key roles in PDT-induced vein graft thrombosis. By inhibiting free radical production or neutrophil adhesion to the graft, adequate PDT can be administered for successful inhibition of vein graft intimal hyperplasia.
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Affiliation(s)
- Giuseppe R Nigri
- Division of Vascular Surgery of General Surgical Servies, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
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7
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Rubens FD. Cardiopulmonary bypass technology transfer: musings of a cardiac surgeon. JOURNAL OF BIOMATERIALS SCIENCE. POLYMER EDITION 2003; 13:485-99. [PMID: 12160305 DOI: 10.1163/156856202320253974] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The development of cardiopulmonary bypass (CPB) has been one of the greatest technical advancements in cardiovascular medicine. With heparin anticoagulation, this device can safely replace the circulatory and gas-exchanging functions of the heart and lung, facilitating complex cardiac operations. Limitations still exist however, related to blood reactions at the biomaterial surface, such as cell activation, inflammation and low-grade thrombosis. In this brief review, the thought processes which paralleled the development of CPB biocompatible surfaces such as heparin-coating, will be explored, as well as current theories on the suspected mechanisms by which heparin-coated surfaces act as an anti-inflammatory device during CPB. Results with new surfaces for CPB designed to capitalize on superior protein adsorption properties, such as surface modifying additive (SMA) and poly (2-methoxyethylacrylate) (PMEA), will also be described. Finally, the significance of biomaterial-independent blood activation will be discussed, emphasizing the current need to develop strategies utilizing optimal biomaterials, modified surgical technique and pharmacologic therapy to minimize the systemic complications of CPB.
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Affiliation(s)
- F D Rubens
- Ottawa Heart Institute, Ontario, Canada.
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8
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Landis ME, Ray EC, Gloviczki P, Miller VM. Effects of dietary L-arginine on structure and function of flow-restricted vein grafts. J Vasc Surg 2001; 33:829-39. [PMID: 11296339 DOI: 10.1067/mva.2001.111987] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PURPOSE Experiments were designed to determine effects of dietary supplementation with L -arginine on structure and function of flow-restricted vein grafts. METHODS Saphenous veins were placed as bilateral interposition grafts in femoral arteries of two groups of adult male mongrel dogs; one group was maintained on a normal diet (control), the other group supplemented with L -arginine (200 mg/kg per day) beginning 1 week before surgery. In each dog, flow was reduced by 50% in one graft by placing an adjustable clamp on the artery distal to the distal anastomosis. Plasma amino acids and oxidized products of nitric oxide (NO(x )) were measured before and after L -arginine feeding. At postoperative week 4, grafts were removed and prepared for organ chamber studies to determine functions of the endothelium or smooth muscle and for histology. RESULTS Plasma L -arginine increased within 3 hours after feeding and increased from 141 +/- 8 nmol/mL to 169 +/- 11 nmol/mL (n = 6) after 5 weeks of supplementation. Plasma ornithine and citrulline paralleled arginine, whereas circulating NO(x ) was unchanged. Maximal contractions to 60 mmol/L KCl were reduced in grafts from L -arginine-fed dogs. Endothelium-dependent relaxations to the calcium ionophore A23187 and relaxations of the smooth muscle NO were reduced in grafts from L -arginine-fed dogs. Neointimal hyperplasia was increased in grafts with reduced flow and not affected by arginine feeding. CONCLUSIONS Dietary supplementation with L -arginine did not increase plasma NO in dogs with peripheral vein grafts or increase endothelium-dependent relaxations in control or flow-restricted grafts. Therefore, dietary supplementation with L -arginine may not improve long-term functions of flow-restricted peripheral bypass grafts.
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Affiliation(s)
- M E Landis
- Department of Surgery, Mayo Foundation, Rochester, MN, USA
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9
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Lee ES, Caldwell MP, Tretinyak AS, Santilli SM. Supplemental oxygen controls cellular proliferation and anastomotic intimal hyperplasia at a vascular graft-to-artery anastomosis in the rabbit. J Vasc Surg 2001; 33:608-13. [PMID: 11241134 DOI: 10.1067/mva.2001.113495] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PURPOSE The purpose of this study was to determine whether the administration of 40% supplemental oxygen (O ( 2) ) will decrease cellular proliferation and intimal hyperplasia (IH) at a prosthetic vascular graft (PVG)-to-artery anastomosis. METHODS Twenty New Zealand white rabbits underwent placement of a 3-mm polytetrafluoroethylene graft in their infrarenal aorta. Four groups of five rabbits were placed either in a normoxic (21%) environment or in a 40% supplemental O ( 2) environment for 7 or 42 days. Twenty-four hours before the rabbits were humanely killed for aortic graft harvest, BrDU (5-bromo-2'-deoxyuridine) was injected into the rabbits intraperitoneally. Image analysis (Bioquant) morphometrics were used to measure cells with BrDU staining and intimal areas at the distal anastomosis. Cellular proliferation is defined as positively staining BrDU cells divided by all cells in the artery wall. IH is reported as a ratio between the intimal area and the medial area to standardize the varying aortic size and degree of aortic fixation among rabbits. The Student t test was used to compare cellular proliferation and IH between control and O ( 2) -treated rabbits. RESULTS Cellular proliferation in the intima at 7 days was significantly reduced in the O ( 2) -treated animals (1.7% +/- 1%) versus the control animals (28.6% +/- 3%) ( P =.0001). The cellular proliferation in the intima at 42 days returned to preoperative levels in the O ( 2) -treated group (0.15%) and in the control group (0.11%) ( P = not significant). IH at 7 days was minimal, and no difference between the O ( 2) -treated group (0.017 +/-.006) and the control group (0.009 +/-.03) ( P = not significant) was found. IH was significantly reduced at 42 days in the O ( 2) -treated animals (0.031 +/-.012) when compared with the control animals (0.193 +/-.043) ( P =.006). CONCLUSIONS Supplemental O ( 2) (40%) significantly reduces cellular proliferation and IH at the distal anastomosis of a PVG-to-artery anastomosis in the rabbit model.
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Affiliation(s)
- E S Lee
- Department of Surgery, University of Minnesota and the Veterans Affairs Medical Center, MN 55417, USA.
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10
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Davies MG, Fulton GJ, Huynh TT, Barber L, Svendsen E, Hagen PO. Combination therapy of cholesterol reduction and L-arginine supplementation controls accelerated vein graft atheroma. Ann Vasc Surg 1999; 13:484-93. [PMID: 10466992 DOI: 10.1007/s100169900288] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hyperlipidemia contributes to the development of intimal hyperplasia and accelerated atheroma in vein bypass grafts. Dietary cholesterol reduction and oral supplementation with L-arginine have been shown to reduce accelerated atheroma in experimental vein grafts. This study extends these observations by examining the effect of the combination therapy of cholesterol reduction and L-arginine supplementation on the development of intimal hyperplasia in vein grafts in hypercholesterolemic animals. Thirty New Zealand White rabbits had a carotid vein bypass graft performed and were sacrificed at 28 days postoperatively either for morphology (light and electron microscopy) and videomorphometry, or for in vitro contractile studies. Twenty animals received a 1% cholesterol diet for 4 weeks prior to surgery. This diet was continued until harvest in ten animals. Ten cholesterol-fed animals received L-arginine supplementation (2 g/kg/day, p.o.) for 7 days preoperatively and thereafter until harvest and in addition were returned to a normal diet on the day of surgery. The last ten animals were controls (normal diet). Combined cholesterol reduction and L-arginine supplementation prevented accelerated atheroma in vein grafts, halted the change in enhanced smooth muscle cell contractility, and improved endothelial cell function. Early postoperative therapy targeting atheroma development in the high-risk patient could offer significant morphological and functional benefits.
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Affiliation(s)
- M G Davies
- Vascular Biology and Atherosclerosis Research Laboratory, Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
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11
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Chirurgische Gefäßmedizin der Zukunft: interdisziplinäre Strategien. Eur Surg 1999. [DOI: 10.1007/bf02620172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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12
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Davies MG, Huynh TT, Fulton GJ, Barber L, Svendsen E, Hagen PO. Early morphology of accelerated vein graft atheroma in experimental vein grafts. Ann Vasc Surg 1999; 13:378-85. [PMID: 10398734 DOI: 10.1007/s100169900272] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Vein grafts fail because of the development of intimal hyperplasia and atheroma. Recent experimental evidence suggests that the presence of hypercholesterolemia induces a three-fold increase in intimal hyperplasia with early atheroma development within 4 weeks of implantation. We have previously demonstrated endothelial cell preservation and a short-lived (3-day) polymorphonuclear leukocyte infiltrate in vein grafts. The aim of this study is to define the early morphology and ultrastructure of vein grafts implanted into a hyperlipidemic environment to provide a pathological foundation on which to examine the cellular and molecular events that determine this accelerated response. Twenty-one male New Zealand White rabbits underwent a right carotid interposition bypass graft using the ipsilateral external jugular vein; all animals received a 1% cholesterol diet for 4 weeks prior to surgery and continuing postoperatively until harvest. Animals (n = 3 per time point) were sacrificed at 60 min, 1 day, 3 days, 5 days, 7 days, 14 days, and 28 days postoperatively for scanning and transmission electron microscopy of the vein grafts. No concurrent controls were employed. The results of this study suggest that in the presence of hypercholesterolemia, the pathophysiological processes involved in the vein graft are similar to those reported for noncholesterol-fed animals. There is a sustained subendothelial response with the prolonged presence of macrophages and cellular debris and the accumulation of foam cells.
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Affiliation(s)
- M G Davies
- Vascular Biology and Atherosclerosis Research Laboratory, Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
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13
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Chen C, Mattar SG, Lumsden AB. Oral administration of L-arginine reduces intimal hyperplasia in balloon-injured rat carotid arteries. J Surg Res 1999; 82:17-23. [PMID: 10068520 DOI: 10.1006/jsre.1998.5476] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Endogenous nitric oxide (NO) is produced from L-arginine by NO synthase. We evaluated the effect of oral administration of L-arginine on intimal hyperplasia in balloon-injured rat carotid arteries. Thirty Sprague-Dawley rats underwent balloon denudation on the left common carotid artery. Fifteen rats were treated with L-arginine in drinking water (2.5 mg/mL) two days before injury and were continued for 2 weeks. Another 15 rats served as controls. All animals survived without complications or body weight loss. In the treated group, daily intake of L-arginine was 170 +/- 43 mg/day. Plasma arginine levels were 130 +/- 32 micromol/L prior to L-arginine intake, 165 +/- 42 micromol/L at the day of injury, and 162 +/- 26 micromol/L at sacrifice. Intimal hyperplasia developed in all balloon-injured arteries in both control and L-arginine-treated animals. However, L-arginine-treated animals showed a 65% reduction of the intima/media area ratio and a 26% reduction of the intimal cell proliferation compared with control animals. These data indicate that adequate amounts of L-arginine were ingested by the rats and that oral administration of L-arginine significantly reduced intimal hyperplasia of balloon-injured arteries without any detectable toxicity.
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Affiliation(s)
- C Chen
- Department of Surgery, Veterans Affairs Medical Center, Decatur, Georgia, 30033, USA
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14
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Fulton GJ, Davies MG, Barber L, Gray JL, Svendsen E, Hagen PO. Local effects of nitric oxide supplementation and suppression in the development of intimal hyperplasia in experimental vein grafts. Eur J Vasc Endovasc Surg 1998; 15:279-89. [PMID: 9610339 DOI: 10.1016/s1078-5884(98)80030-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVES The universal response of vein grafts after insertion into the arterial circulation is the development of intimal hyperplasia; smooth muscle cell proliferation and connective tissue deposition, which may be modulated in part by dysfunctional endothelial nitric oxide (NO) metabolism. This study examines the effects of single dose, local application by pluronic gel of a NO donor, S-nitroso-N-acetylpenicillamine (SNAP) and an NO synthase inhibitor nitro-L-arginine methyl ester (L-NAME) on the formation of intimal hyperplasia. MATERIALS Forty New Zealand white rabbits underwent jugular vein interposition grafting of the common carotid artery. DESIGN Ten animals were controls, 10 animals had the outer surface of the vein graft coated with 30% pluronic gel (2.5 ml), and 10 each were immersed for 15 min prior to insertion in Ringer lactate containing 10(-3) M of SNAP or L-NAME and then had their vein grafts coated with 2.5 ml of gel containing either SNAP (10(-3) M) or L-NAME (10(-3) M), which allows for sustained delivery for up to 6 h. On the 28th post operative day, the animals were sacrificed and vein grafts were harvested for morphology by electron microscopy (SEM and TEM) and dimensional analysis by videomorphometry. RESULTS All vein grafts developed intimal hyperplasia. On SEM the vein grafts had a confluent layer of endothelial cells with multiple layers of smooth muscle cells representing intimal hyperplasia in TEM. There were no demonstrable morphological differences between the four groups. Local treatment with SNAP produced a significant 36% decrease in mean intimal thickness (72 +/- 4 microns vs. 45 +/- 4 microns; mean +/- S.E.M.; p < 0.01) without a change in medial thickness compared to gel-only treated groups (58 +/- 6 microns vs. 61 +/- 7 microns; p = ns). Inhibition of NO synthase by L-NAME had no effect on the development of intimal hyperplasia (72 +/- 4 microns vs. 79 +/- 10 microns; p = ns); medial thickness was also unchanged. CONCLUSION These data confirm the protective effect of NO in vascular injury and suggest that NO synthase activity is either absent or reduced to such a level that further inhibition in this short time course is not relevant to the pathophysiology of vein graft intimal hyperplasia.
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MESH Headings
- Animals
- Carotid Artery, Common/surgery
- Cell Division/drug effects
- Cells, Cultured/drug effects
- Collagen/biosynthesis
- Collagen/drug effects
- Collagen/ultrastructure
- Cytoplasm/drug effects
- Cytoplasm/ultrastructure
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/ultrastructure
- Female
- Hyperplasia/chemically induced
- Microscopy, Electron, Scanning
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/ultrastructure
- NG-Nitroarginine Methyl Ester/administration & dosage
- Penicillamine/administration & dosage
- Penicillamine/analogs & derivatives
- Rabbits
- Vascular Patency
- Veins/pathology
- Veins/transplantation
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Affiliation(s)
- G J Fulton
- Department of Surgery, Duke University Medical Center, North Carolina 27710, USA
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Fulton GJ, Davies MG, Barber L, Svendsen E, Hagen PO. Localized versus systemic angiotensin II receptor inhibition of intimal hyperplasia in experimental vein grafts by the specific angiotensin II receptor inhibitor L158,809. Surgery 1998. [DOI: 10.1016/s0039-6060(98)70261-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Fulton GJ, Barber L, Svendsen E, Hagen PO, Davies MG. Oral monoterpene therapy (perillyl alcohol) reduces vein graft intimal hyperplasia. J Surg Res 1997; 69:128-34. [PMID: 9202658 DOI: 10.1006/jsre.1997.5047] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The development of intimal hyperplasia is recognized as a major impediment to graft patency. D-Limonenes are monoterpenes with a recognized cytostatic effect on cell proliferation by inhibiting posttranslational isoprenylation of p21ras and other small G-proteins. This study examines the effect of perillyl alcohol, an oral hydroxylated D-limonene, on the development of intimal hyperplasia and its associated smooth muscle cell physiological responses in an experimental model of vein bypass grafting. Twenty New Zealand white rabbits had a right carotid interposition bypass graft using the ipsilateral external jugular vein. Ten animals received chronic oral therapy with a perillyl alcohol (200 mg/kg/day; begun 5 days before surgery and continued until harvest) and 10 control animals received vehicle only. All animals were sacrificed on the 28th postoperative day. Vein grafts were harvested either for morphology/videomorphometry (n = 6 per group) or for in vitro isometric tension studies (n = 4; four 5-mm rings per graft). The cell proliferation and incorporation of [3H]thymidine into the cellular DNA of serum-stimulated rabbit aortic smooth muscle cells was also assessed in the presence of increasing concentrations of perillyl alcohol (10(-9)-10(-4) M). Perillyl alcohol treated vein grafts showed a 22% reduction in overall mean intimal thickness (54 +/- 4 microns vs 69 +/- 3 microns; P = 0.006) but a 25% increase in overall mean medial thickness (86 +/- 4 microns vs 61 +/- 3 microns). The intimal ratio of the perillyl alcohol treated vein grafts decreased by 27% compared to controls. Perillyl alcohol induced norepinephrine and serotonin hypersensitivity in vein grafts compared to controls. The IC50 for perillyl alcohol was 176 nM with maximal inhibition at 5 microM. Incubation of smooth muscle cell cultures with increasing concentrations of perillyl alcohol showed a dose-dependent decrease in in vitro cellular proliferation, maximal at 1 microM. Therapy with perillyl alcohol alters the early development of intimal hyperplasia reducing the intimal response but increasing the medial response without significant changes in the physiological responses of the smooth muscle cells. Modulating G-proteins will affect the intimal hyperplastic response in vein grafts.
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Affiliation(s)
- G J Fulton
- Department of Surgery and Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
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Davies MG, Dalen H, Svendsen E, Hagen PO. Functional and histological differences in autogenous and allogenic vein grafts: two different vasculopathies? J Surg Res 1997; 69:14-22. [PMID: 9202641 DOI: 10.1006/jsre.1997.5019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The long-term biological characteristics and the functional and morphological changes that occur in fresh allografts are poorly understood. This study tests the hypothesis that the development of intimal hyperplasia and its associated functional changes are accelerated in an allograft compared to an autograft due to the additional immunological stimuli. Common carotid vein bypass grafts were performed in 40 New Zealand White rabbits: 20 received their ipsilateral jugular veins (autologous) and 20 received the fresh contralateral jugular veins from the control rabbit (allogenic). Electron microscopy was performed and intimal and medial dimensions were determined by videoplanimetry at 7, 14, and 28 days. Contraction and relaxation studies to a panel of agonists were also performed. The EC50's (agonist concentration which produces 50% of the maximal response) were calculated. All grafts remained patent. Allografts showed a 51% decrease in overall mean intimal thickness (41 +/- 3 microns vs. 83 +/- 12 microns; P < 0.01) and a 97% increase in overall mean medial thickness (140 +/- 15 microns vs. 71 +/- 3 microns; P < 0.01) compared to the autografts. The lumen of the allogenic vein grafts was equivalent to the autologous vein grafts. Overall mean total wall thickness only increased by 17%, 181 microns vs. 154 microns for allo- and autografts, respectively. The EC50 for norepinephrine, histamine, and bradykinin were similar in the auto- and allografts, while the EC50 to serotonin was significantly less in the allografts than in the autografts. Neither the precontracted auto- or allografts relaxed to acetylcholine or serotonin (receptor mediated, endothelium dependent). The EC50 for calcium ionophore (nonreceptor mediated, endothelium dependent) was equivalent in the auto- and allografts. The EC50 for the sodium nitroprusside-induced relaxation (endothelium independent) was significantly higher in the allograft than in the autograft. This study demonstrates that there are two different vasculopathies occurring in autografts and allografts: intimal hyperplasia is predominant in the autograft while an exaggerated medial response is predominant in the allograft. Serotonin contractility and endothelial-independent relaxation are enhanced in the allograft compared to the autograft.
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Affiliation(s)
- M G Davies
- Vascular Biology and Atherosclerosis Research Laboratory, Duke University Medical Center, Durham, North Carolina 27710, USA
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Fulton GJ, Davies MG, Koch WJ, Dalen H, Svendsen E, Hagen PO. Antisense oligonucleotide to proto-oncogene c-myb inhibits the formation of intimal hyperplasia in experimental vein grafts. J Vasc Surg 1997; 25:453-63. [PMID: 9081126 DOI: 10.1016/s0741-5214(97)70255-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND The development of intimal hyperplasia is a major cause of early vein graft failure. The study examines the effects of locally delivered antisense oligonucleotides to the proto-oncogene c-myb on the development of vein graft intimal hyperplasia. METHODS Common carotid vein bypass grafting procedures were performed on 60 New Zealand White rabbits. Seventeen grafts were controls, 14 had grafts coated with a commercial gel, 17 had grafts coated with gel containing 200 micrograms of an antisense c-myb oligonucleotide, and 6 rabbits each had grafts coated with gel containing one of two control oligonucleotides. Grafts were harvested 28 days after surgery, and sections were taken for dimensional analysis, morphologic evaluation, and vasomotor function. Grafts were also harvested at 1 day for oligonucleotide uptake/localization analysis and at 3 days for c-myb mRNA analysis. RESULTS Oligonucleotides were uniformly distributed within the media and adventitia by 1 day. A 38% reduction occurred in mean intimal thickness in the vein grafts coated with antisense to c-myb compared with the other groups. No difference in medial thickness was seen among groups. By scanning and transmission electron microscopy all vein grafts showed a confluent endothelium. In contrast to control vein grafts, which did not relax to acetylcholine, most of the gel and all of the gel/oligonucleotide-coated grafts relaxed by more than 40% of precontracted tension. Responses to a panel of contractile agents were unchanged in the treated groups compared with those in the control group. CONCLUSIONS Locally delivered antisense oligonucleotides to proto-oncogene c-myb significantly reduces intimal hyperplasia with preservation of acetylcholine-mediated endothelium-dependent relaxation in experimental vein grafts. These findings suggest that targeting a common regulatory pathway of vascular smooth muscle mitogenesis can be successful in reducing the early development of intimal hyperplasia.
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Affiliation(s)
- G J Fulton
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
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