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Zhang W, Fukazawa K, Mahara A, Le HT, Soni R, Yamaoka T. Reliable Surface Modification of ePTFE Using a Photoreactive Hemocompatible Peptide to Promote Endothelial Affinity and Antiplatelet Efficacy. ACS Biomater Sci Eng 2025. [PMID: 40325826 DOI: 10.1021/acsbiomaterials.5c00236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2025]
Abstract
Expanded polytetrafluoroethylene (ePTFE) is a widely used material in diverse medical devices, particularly in the cardiovascular system, owing to its chemical stability and suitable mechanical properties. However, the chemical inertness makes surface modification difficult. In the present study, modification of ePTFE with a peptide was successfully achieved based on a unique photoreaction technique. We previously screened the hemocompatible peptide (HCP), histidine-glycine-glycine-valine-arginine-leucine-tyrosine (HGGVRLY), with high endothelial affinity and antiplatelet ability as modifying molecules. We synthesized a photoreactive peptide by combining a phenylazide group with the HCP, which was subsequently immobilized on the ePTFE surface through a short UV exposure time after argon plasma (Ar) treatment. Cross-sectional images of the surface modified with fluorescent-labeled photoreactive HCP showed efficient modification even within the pores of ePTFE. In vitro assessment revealed that modification improved the endothelial affinity of ePTFE approximately 5-fold while preventing platelet adhesion and aggregation. The ePTFE grafts were further implanted into an in situ porcine closed-circuit system for the blood contact assessment. Comparative investigations with untreated ePTFE grafts indicated that the modified ePTFE surface attracted more cells positive for CD14, CD16, CD34, and macrophage markers while concurrently exhibiting reduced platelet adhesion. In conclusion, photoreactive HCP proved to be a simple and effective strategy for modifying the ePTFE surface, resulting in enhanced hemocompatibility characterized by increased endothelial and monocyte recruitment as well as antiplatelet attachment on the modified ePTFE graft surface.
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Affiliation(s)
- Wei Zhang
- National Cerebral and Cardiovascular Center Research Institute, 6-1 Kishibe Shim-machi, Suita, Osaka 564-8565, Japan
- Plastic Surgery Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100144, China
| | - Kyoko Fukazawa
- National Cerebral and Cardiovascular Center Research Institute, 6-1 Kishibe Shim-machi, Suita, Osaka 564-8565, Japan
| | - Atsushi Mahara
- National Cerebral and Cardiovascular Center Research Institute, 6-1 Kishibe Shim-machi, Suita, Osaka 564-8565, Japan
| | - Hue Thi Le
- National Cerebral and Cardiovascular Center Research Institute, 6-1 Kishibe Shim-machi, Suita, Osaka 564-8565, Japan
| | - Raghav Soni
- National Cerebral and Cardiovascular Center Research Institute, 6-1 Kishibe Shim-machi, Suita, Osaka 564-8565, Japan
| | - Tetsuji Yamaoka
- National Cerebral and Cardiovascular Center Research Institute, 6-1 Kishibe Shim-machi, Suita, Osaka 564-8565, Japan
- Department of Clinical Engineering, Faculty of Health Sciences, Komatsu University, He 14-1, Mukai-motoori-machi, Komatsu, Ishikawa 923-0961, Japan
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2
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Meer E, Ahmad M, Lifton J, Mosenia A, Ashraf DC, Grob S, Vagefi MR, Winn BJ, Kersten RC. Outcomes for expanded polytetrafluoroethylene strip in frontalis suspension surgery. Orbit 2024; 43:307-315. [PMID: 38236954 DOI: 10.1080/01676830.2023.2300793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 12/22/2023] [Indexed: 06/13/2024]
Abstract
PURPOSE This study evaluates surgical outcomes and complication rates of frontalis suspension with expanded polytetrafluoroethylene (ePTFE). METHODS This retrospective cohort study reviewed all patients undergoing frontalis suspension surgery using ePTFE as the sling material from January 1 2012 to March 3 2020 by a single surgeon at a single academic center. Two different surgical techniques were evaluated in the placement of the sling material. Demographic, clinical, and operative data were extracted. Outcome data including postoperative lid height, reoperation, and complication rate were extracted for the cohort and compared between the two surgical techniques. Descriptive statistics were utilized. RESULTS Sixty-four eyes from 49 unique patients were included in this study. Forty-three (67.2%) patients had isolated congenital blepharoptosis; 14 (21.9%) had blepharophimosis, ptosis, and epicanthus inversus syndrome (BPES); and 2 (3.1%) had cranial nerve III palsy. Fifty-one (79.7%) patients had no prior blepharoptosis surgery. Lid crease incision and stab incision techniques were utilized for 24 (37.5%) and 40 (62.5%) eyes, respectively. Overall, 21 (32.8%) eyes required reoperation with ePTFE to achieve appropriate eyelid height or contour. Only one patient experienced implant infection, requiring removal of ePTFE sling after a second reoperation. There were no cases of implant exposure or granuloma formation noted during the study period. CONCLUSION An ePTFE strip soaked in cefazolin prior to utilization in surgery is a viable material for frontalis suspension surgery, with a lower infectious or inflammatory complication rate than previously reported. However, reoperation rate was still relatively high.
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Affiliation(s)
- Elana Meer
- Department of Ophthalmology, University of California, San Francisco, California, USA
| | - Meleha Ahmad
- Department of Ophthalmology, University of California, San Francisco, California, USA
- Division of Oculofacial Plastic and Orbital Surgery, Department of Ophthalmology, University of California, San Francisco, California, USA
| | - Jacob Lifton
- Department of Ophthalmology, University of California, San Francisco, California, USA
| | - Arman Mosenia
- Department of Ophthalmology, University of Texas, Austin, Texas, USA
| | - Davin C Ashraf
- Division of Oculofacial Plastic and Orbital Surgery, Department of Ophthalmology, Oregon Health & Sciences University, Portland, Oregon, USA
| | - Seanna Grob
- Department of Ophthalmology, University of California, San Francisco, California, USA
- Division of Oculofacial Plastic and Orbital Surgery, Department of Ophthalmology, University of California, San Francisco, California, USA
| | - M Reza Vagefi
- Department of Ophthalmology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Bryan J Winn
- Department of Ophthalmology, University of California, San Francisco, California, USA
- Division of Oculofacial Plastic and Orbital Surgery, Department of Ophthalmology, University of California, San Francisco, California, USA
- Ophthalmology Section, Surgical Service, San Francisco Veterans Affairs Medical Center, San Francisco, California, USA
| | - Robert C Kersten
- Department of Ophthalmology, University of California, San Francisco, California, USA
- Division of Oculofacial Plastic and Orbital Surgery, Department of Ophthalmology, University of California, San Francisco, California, USA
- Division of Oculofacial Plastic and Orbital Surgery, Department of Ophthalmology, University of Utah, Salt Lake City, Utah, USA
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3
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Lawson JH, Niklason LE, Roy-Chaudhury P. Challenges and novel therapies for vascular access in haemodialysis. Nat Rev Nephrol 2020; 16:586-602. [PMID: 32839580 PMCID: PMC8108319 DOI: 10.1038/s41581-020-0333-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/21/2020] [Indexed: 02/07/2023]
Abstract
Advances in standards of care have extended the life expectancy of patients with kidney failure. However, options for chronic vascular access for haemodialysis - an essential part of kidney replacement therapy - have remained unchanged for decades. The high morbidity and mortality associated with current vascular access complications highlights an unmet clinical need for novel techniques in vascular access and is driving innovation in vascular access care. The development of devices, biological approaches and novel access techniques has led to new approaches to controlling fistula geometry and manipulating the underlying cellular and molecular pathways of the vascular endothelium, and influencing fistula maturation and formation through the use of external mechanical methods. Innovations in arteriovenous graft materials range from small modifications to the graft lumen to the creation of completely novel bioengineered grafts. Steps have even been taken to create new devices for the treatment of patients with central vein stenosis. However, these emerging therapies face difficult hurdles, and truly creative approaches to vascular access need resources that include well-designed clinical trials, frequent interaction with regulators, interventionalist education and sufficient funding. In addition, the heterogeneity of patients with kidney failure suggests it is unlikely that a 'one-size-fits-all' approach for effective vascular access will be feasible in the current environment.
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Affiliation(s)
- Jeffrey H Lawson
- Department of Surgery, Duke University, Durham, NC, USA.
- Humacyte, Inc., Durham, NC, USA.
| | - Laura E Niklason
- Humacyte, Inc., Durham, NC, USA
- School of Engineering & Applied Science, Yale University, New Haven, CT, USA
| | - Prabir Roy-Chaudhury
- University of North Carolina Kidney Center, Chapel Hill, NC, USA
- WG (Bill) Hefner VA Medical Center, Salisbury, NC, USA
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4
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Gregory EK, Webb A, Vercammen JM, Kelly ME, Akar B, van Lith R, Bahnson EM, Jiang W, Ameer GA, Kibbe MR. Inhibiting intimal hyperplasia in prosthetic vascular grafts via immobilized all-trans retinoic acid. J Control Release 2018; 274:69-80. [PMID: 29391231 PMCID: PMC5847482 DOI: 10.1016/j.jconrel.2018.01.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 12/15/2017] [Accepted: 01/22/2018] [Indexed: 12/24/2022]
Abstract
Peripheral arterial disease is a leading cause of morbidity and mortality. The most commonly utilized prosthetic material for peripheral bypass grafting is expanded polytetrafluoroethylene (ePTFE) yet it continues to exhibit poor performance from restenosis due to neointimal hyperplasia, especially in femoral distal bypass procedures. Recently, we demonstrated that periadventitial delivery of all-trans retinoic acid (atRA) immobilized throughout porous poly(1,8 octamethylene citrate) (POC) membranes inhibited neointimal formation in a rat arterial injury model. Thus, the objective of this study was to investigate whether atRA immobilized throughout the lumen of ePTFE vascular grafts would inhibit intimal formation following arterial bypass grafting. Utilizing standard ePTFE, two types of atRA-containing ePTFE vascular grafts were fabricated and evaluated: grafts whereby all-trans retinoic acid was directly immobilized on ePTFE (atRA-ePTFE) and grafts where all-trans retinoic acid was immobilized onto ePTFE grafts coated with POC (atRA-POC-ePTFE). All grafts were characterized by SEM, HPLC, and FTIR and physical characteristics were evaluated in vitro. Modification of these grafts, did not significantly alter their physical characteristics or biocompatibility, and resulted in inhibition of intimal formation in a rat aortic bypass model, with atRA-POC-ePTFE inhibiting intimal formation at both the proximal and distal graft sections. In addition, treatment with atRA-POC-ePTFE resulted in increased graft endothelialization and decreased inflammation when compared to the other treatment groups. This work further confirms the biocompatibility and efficacy of locally delivered atRA to inhibit intimal formation in a bypass setting. Thus, atRA-POC-ePTFE grafts have the potential to improve patency rates in small diameter bypass grafts and warrant further investigation.
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Affiliation(s)
- Elaine K Gregory
- Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States; Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL 60611, United States
| | - Antonio Webb
- The University of Florida, Gainesville, FL 32611, United States
| | - Janet M Vercammen
- Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States; Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL 60611, United States
| | - Megan E Kelly
- Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States; Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL 60611, United States
| | - Banu Akar
- Biomedical Engineering Department, McCormick School of Engineering, Northwestern University, Evanston, IL 60201, United States
| | - Robert van Lith
- Biomedical Engineering Department, McCormick School of Engineering, Northwestern University, Evanston, IL 60201, United States; Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL 60611, United States
| | - Edward M Bahnson
- Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
| | - Wulin Jiang
- Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States; Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL 60611, United States
| | - Guillermo A Ameer
- Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States; Biomedical Engineering Department, McCormick School of Engineering, Northwestern University, Evanston, IL 60201, United States; Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL 60611, United States
| | - Melina R Kibbe
- Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States; Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL 60611, United States; Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States.
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5
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Wise SG, Liu H, Kondyurin A, Byrom MJ, Bannon PG, Edwards GA, Weiss AS, Bao S, Bilek MM. Plasma Ion Activated Expanded Polytetrafluoroethylene Vascular Grafts with a Covalently Immobilized Recombinant Human Tropoelastin Coating Reducing Neointimal Hyperplasia. ACS Biomater Sci Eng 2016; 2:1286-1297. [DOI: 10.1021/acsbiomaterials.6b00208] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Steven G. Wise
- The Heart Research Institute, 7 Eliza Street, Newtown, Sydney, New South Wales 2042, Australia
- Sydney
Medical School, University of Sydney, Edward Ford Building (A27), Fisher
Road, Sydney, New South Wales 2006, Australia
- School
of Molecular Bioscience, University of Sydney, Biochemistry Building (G08), Butlin
Avenue, Sydney, New South
Wales 2006, Australia
| | - Hongjuan Liu
- Department
of Pathology, University of Sydney, Blackburn Building (D06), Blackburn Circuit, Sydney, New South Wales 2006, Australia
| | - Alexey Kondyurin
- School
of Physics (A28), University of Sydney, Physics Road, Sydney, New South Wales 2006, Australia
| | - Michael J. Byrom
- The Heart Research Institute, 7 Eliza Street, Newtown, Sydney, New South Wales 2042, Australia
- The Baird Institute, Suite 305, 100 Carillon Avenue, Newtown, Sydney, New South Wales 2042, Australia
| | - Paul G. Bannon
- Sydney
Medical School, University of Sydney, Edward Ford Building (A27), Fisher
Road, Sydney, New South Wales 2006, Australia
- The Baird Institute, Suite 305, 100 Carillon Avenue, Newtown, Sydney, New South Wales 2042, Australia
| | - Glenn A. Edwards
- School
of Veterinary Science, University of Melbourne, 757 Swanston Street, Parkville, Victoria 3030, Australia
| | - Anthony S. Weiss
- School
of Molecular Bioscience, University of Sydney, Biochemistry Building (G08), Butlin
Avenue, Sydney, New South
Wales 2006, Australia
- Bosch
Institute, University of Sydney, Anderson Stuart Building (F13), Fisher Road, Sydney, New
South Wales 2006, Australia
- Charles
Perkins Centre (D17), University of Sydney, John Hopkins Drive, Sydney, New South Wales 2006, Australia
| | - Shisan Bao
- Department
of Pathology, University of Sydney, Blackburn Building (D06), Blackburn Circuit, Sydney, New South Wales 2006, Australia
| | - Marcela M. Bilek
- School
of Physics (A28), University of Sydney, Physics Road, Sydney, New South Wales 2006, Australia
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6
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Bastijanic JM, Kligman FL, Marchant RE, Kottke-Marchant K. Dual biofunctional polymer modifications to address endothelialization and smooth muscle cell integration of ePTFE vascular grafts. J Biomed Mater Res A 2015; 104:71-81. [DOI: 10.1002/jbm.a.35541] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Revised: 07/10/2015] [Accepted: 07/14/2015] [Indexed: 01/02/2023]
Affiliation(s)
| | - Faina L. Kligman
- Robert J. Tomsich Pathology and Laboratory Medicine Institute, Cleveland Clinic; Cleveland Ohio
| | - Roger E. Marchant
- Department of Biomedical Engineering; Case Western Reserve University; Cleveland Ohio
| | - Kandice Kottke-Marchant
- Department of Biomedical Engineering; Case Western Reserve University; Cleveland Ohio
- Robert J. Tomsich Pathology and Laboratory Medicine Institute, Cleveland Clinic; Cleveland Ohio
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7
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Han Q, Wang Y, Li X, Peng R, Li A, Qian Z, Yu L. Effects of bevacizumab loaded PEG-PCL-PEG hydrogel intracameral application on intraocular pressure after glaucoma filtration surgery. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2015; 26:225. [PMID: 26286760 DOI: 10.1007/s10856-015-5556-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 08/06/2015] [Indexed: 06/04/2023]
Abstract
PEG-PCL-PEG (PECE) hydrogel for intracameral injection as a sustained delivery system can get a stable release of the medication and achieve an effective local concentration. The injectable PECE hydrogel is thermosensitive nano-material which is flowing sol at low temperature and can shift to nonflowing gel at body temperature. This study evaluated the intracameral injection of bevacizumab combined with a PECE hydrogel drug release system on postoperative scarring and bleb survival after experimental glaucoma filtration surgery. The best result was achieved in the bevacizumab loaded PECE hydrogels group, which presented the lowest IOP values after surgery. And the blebs were significantly more persistent in this group. Histology, Massion trichrome staining and immunohistochemistry further demonstrated that glaucoma filtration surgery in combination with bevacizumab loaded PECE hydrogel resulted in good bleb survival due to scar formation inhibition. In conclusions, this study demonstrated that bevacizumab-loaded PECE hydrogel for intracameral injection as a sustained delivery system provide a great opportunity to increase the therapeutic efficacy of glaucoma filtration surgery.
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Affiliation(s)
- Qian Han
- Department of Ophthalmology, Affiliated Hospital of Luzhou Medical College, Luzhou, 646000, Sichuan Province, China
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8
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Nichols MD, Choudhary R, Kodali S, Reichert WM. Coagulation-induced resistance to fluid flow in small-diameter vascular grafts and graft mimics measured by purging pressure. J Biomed Mater Res B Appl Biomater 2014; 101:1367-76. [PMID: 24591220 DOI: 10.1002/jbm.b.32954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2012] [Revised: 01/09/2013] [Accepted: 02/11/2013] [Indexed: 11/07/2022]
Abstract
In this study, the coagulation-induced resistance to flow in small-diameter nonpermeable Tygon tubes and permeable expanded polytetrafluoroethylene (ePTFE) vascular grafts was characterized by measuring the upstream pressure needed to purge the coagulum from the tube lumen. This purging pressure was monitored using a closed system that compressed the contents of the tubes at a constant rate. The pressure system was validated using a glycerin series with well-defined viscosities and precisely controlled reductions in cross-sectional area available for flow. This system was then used to systematically probe the upstream pressure buildup as fibrin glue, platelet-rich plasma (PRP) or whole blood coagulated in small-diameter Tygon tubing and or ePTFE grafts. The maximum purging pressures rose with increased clot maturity for fibrin glue, PRP, and whole blood in both Tygon and ePTFE tubes. Although the rapidly coagulating fibrin glue in nonpermeable Tygon tubing yielded highly consistent purging curves, the significantly longer and more variable clotting times of PRP and whole blood, and the porosity of ePTFE grafts, significantly diminished the consistency of the purging curves.
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Affiliation(s)
- Michael D Nichols
- Department of Biomedical Engineering, Center for Biomolecular and Tissue Engineering, Duke University, Durham, North Carolina, 27708
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9
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Mussa FF, Hedayati N, Zhou W, El-Sayed HF, Kougias P, Darouiche RO, Lin PH. Prevention and treatment of aortic graft infection. Expert Rev Anti Infect Ther 2014; 5:305-15. [PMID: 17402845 DOI: 10.1586/14787210.5.2.305] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Prosthetic vascular graft infection remains one of the most challenging surgical problems for vascular surgeons. This condition is classically associated with high morbidity and mortality rates. Accurate diagnosis of a vascular graft infection can typically be made based on a thorough history and physical examination; although, infrequently, an extensive radiological evaluation is necessary to establish the clinical finding. Complete graft excision and extra-anatomic bypass grafting remains a commonly accepted surgical treatment strategy. Recent clinical data have supported other treatment modalities, including the use of in situ antibiotic-impregnated graft replacement, in situ allograft replacement and in situ autologous graft replacement. This article will review the pathobiology of aortic graft infection, as well as methods to prevent a prosthetic graft infection. Furthermore, various surgical treatment modalities of aortic graft infection will be discussed.
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Affiliation(s)
- Firas F Mussa
- The Michael E DeBakey VA Medical Center, Division of Vascular Surgery & Endovascular Therapy, Michael E DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX, USA.
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10
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Basilic vein transposition versus biosynthetic prosthesis as vascular access for hemodialysis. J Vasc Surg 2011; 54:1713-9. [DOI: 10.1016/j.jvs.2011.06.030] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2011] [Revised: 06/15/2011] [Accepted: 06/15/2011] [Indexed: 11/24/2022]
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11
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Liu K, Cao G, Zhang X, Liu R, Zou W, Wu S. Pretreatment with intraluminal rapamycin nanoparticle perfusion inhibits neointimal hyperplasia in a rabbit vein graft model. Int J Nanomedicine 2010; 5:853-60. [PMID: 21042547 PMCID: PMC2963931 DOI: 10.2147/ijn.s13112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
PURPOSE Poly lactic-co-glycolic acid nanoparticles (PLGA-NP) are widely used as a biodegradable biomaterial in medicine. Rapamycin-eluting stents have been used for prevention of restenosis during surgery. This study investigated the effect of pretreatment with intraluminal perfusion of carbopol-encapsulated rapamycin-loaded PLGA nanoparticles (RAP-PLGA-NP) on neointimal hyperplasia in a rabbit vein graft model. METHODS A segment of common carotid artery was replaced with a segment of external jugular vein in 60 rabbits which were then separated into four treatment groups, ie, Group 1, in which vein grafts were pretreated with intraluminal RAP-PLGA-NP perfusion, Group 2 in which vein grafts underwent equivalent empty vehicle (PLGA-NP) perfusion, Group 3, in which vein grafts received no treatment, and Group 4, which served as a sham operation group receiving normal vein contrast. On postoperative day 28, the grafts and normal veins were harvested for histologic examination, flow cytometry analysis, and high-performance liquid chromatography measurement. RESULTS Compared with Group 1, the intima of the grafts were thickened, the ratio of intimal area to vessel area increased, and the collagen volume index of the vein grafts increased significantly in Groups 2 and 3. The cell proliferation index in Group 1 (21.11 ± 3.15%) was much lower than that in Group 2 (30.35 ± 2.69%) and in Group 3 (33.86 ± 8.72%). By high-performance liquid chromatography measurement, retention of rapamycin was detected in Group 1 (11.2 ± 0.37 μg/10 mg) 28 days after single drug perfusion. CONCLUSION Pretreatment with intraluminal RAP-PLGA-NP perfusion may inhibit neointimal hyperplasia in vein grafts by penetrating into local tissue and limiting cell proliferation.
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Affiliation(s)
- Kai Liu
- Department of Cardiovascular Surgery, Qilu Hospital of Shandong University, Jinan, People’s Republic of China
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12
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Allen JB, Khan S, Lapidos KA, Ameer GA. Toward engineering a human neoendothelium with circulating progenitor cells. Stem Cells 2010; 28:318-28. [PMID: 20013827 DOI: 10.1002/stem.275] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Tissue-engineered vascular grafts may one day provide a solution to many of the limitations associated with using synthetic vascular grafts. However, identifying a suitable cell source and polymer scaffold to recreate the properties of a native blood vessel remains a challenge. In this work, we assess the feasibility of using endothelial progenitor cells (EPCs) found in circulating blood to generate a functional endothelium on poly(1,8-octanediol-co-citrate) (POC), a biodegradable elastomeric polyester. EPCs were isolated from human blood and biochemically differentiated into endothelial-like cells (HE-like) in vitro. The differentiated cell phenotype and function was confirmed by the appearance of the characteristic endothelial cell (EC) cobblestone morphology and positive staining for EC markers, von Willebrand factor, vascular endothelial cadherin, flk-1, and CD31. In addition, HE-like cells cultured on POC express endothelial nitric oxide synthase at levels comparable to aortic ECs. Furthermore, as with mature endothelial cells, HE-like cell populations show negligible expression of tissue factor. Similarly, HE-like cells produce and secrete prostacyclin and tissue plasminogen activator at levels comparable to venous and aortic ECs. When compared to fibroblast cells, HE-like cells cultured on POC show a decrease in the rate of plasma and whole-blood clot formation as well as a decrease in platelet adhesion. Finally, the data show that HE-like cells can withstand physiological shear stress of 10 dynes/cm(2) when cultured on POC-modified expanded poly(tetrafluoroethylene) vascular grafts. Collectively, these data are the foundation for future clinical studies in the creation of an autologous endothelial cell-seeded vascular graft.
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13
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Kibbe MR, Martinez J, Popowich DA, Kapadia MR, Ahanchi SS, Aalami OO, Jiang Q, Webb AR, Yang J, Carroll T, Ameer GA. Citric acid-based elastomers provide a biocompatible interface for vascular grafts. J Biomed Mater Res A 2010; 93:314-24. [PMID: 19569210 DOI: 10.1002/jbm.a.32537] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Prosthetic vascular bypass grafting is associated with poor long-term patency rates. Herein, we report on the mid-term performance of expanded polytetrafluoroethylene (ePTFE) vascular grafts modified with a citric acid-based biodegradable elastomer. Through a spin-shearing method, ePTFE grafts were modified by mechanically coating a layer of poly(1,8 octanediol citrate) (POC) onto the luminal nodes and fibrils of the ePTFE. Control and POC-ePTFE grafts were implanted into the porcine carotid artery circulation as end-to-side bypass grafts. Grafts were assessed by duplex ultrasonography, magnetic resonance angiography, and digital subtraction contrast angiography and were all found to be patent with no hemodynamically significant stenoses. At 4 weeks, POC-ePTFE grafts were found to be biocompatible and resulted in a similar extent of neointimal hyperplasia as well as leukocyte and monocyte/macrophage infiltration as control ePTFE grafts. Furthermore, POC supported endothelial cell growth. Lastly, scanning electron microscopy confirmed the presence of POC on the ePTFE grafts at 4 weeks. Thus, these data reveal that surface modification of blood-contacting surfaces with POC results in a biocompatible surface that does not induce any untoward effects or inflammation in the vasculature. These findings are important as they will serve as the foundation for the development of a drug-eluting vascular graft.
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Affiliation(s)
- Melina R Kibbe
- Division of Vascular Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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14
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Antibiotic-Coated ePTFE Decreases Graft Colonization and Neointimal Hyperplasia. J Surg Res 2009; 156:199-204. [DOI: 10.1016/j.jss.2009.01.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Revised: 01/12/2009] [Accepted: 01/13/2009] [Indexed: 11/22/2022]
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15
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Sapienza P, di Marzo L, Cucina A, Borrelli V, Mosiello G, Basile U, Iacovitti S, Cavallaro A. The effect of locally administered anti-growth factor antibodies on neointimal hyperplasia formation in expanded polytetrafluoroethylene grafts. Ann Vasc Surg 2009; 23:398-409. [PMID: 19427566 DOI: 10.1016/j.avsg.2008.11.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2008] [Revised: 11/25/2008] [Accepted: 11/26/2008] [Indexed: 11/29/2022]
Abstract
The selective blockage of platelet-derived growth factor BB (PDGF-BB), basic fibroblast growth factor (bFGF), and transforming growth factor beta1 (TGF-beta1) by specific antibodies coated into expanded polytetrafluoroethylene (ePTFE) grafts may diminish neointimal hyperplasia. Sixty pigs were divided into two groups (n = 30 each) and then further divided into five subgroups. Group 1 had a bilateral iliac artery ePTFE interposition graft precoated with Matrigel. Three subgroups (A, B, and C) received a specific monoclonal antibody against PDGF-BB, bFGF, or TGF-beta1. One (D) received all antibodies, and one served as control (nonimmune immunoglobulin G [IgG] isotypes) (E). Group 2 had a bilateral iliac artery endothelial cell (EC)-seeded ePTFE interposition graft precoated with Matrigel. Three subgroups (A, B, and C) received a specific antibody against PDGF-BB, bFGF, or TGF-beta1. One (D) received all antibodies, and one served as control (nonimmune IgG isotypes) (E). Light microscopy and immunohistochemical stain showed that neointimal hyperplasia formation was significantly reduced in subgroups D compared to the others (p < 0.05). In subgroups D, the different precoating influenced neointimal hyperplasia formation. It was more pronounced in the prosthesis precoated with EC and Matrigel (p < 0.05). In organ culture, the amount of PDGF-BB, bFGF, and TGF-beta1 release was reduced in subgroup D animals compared to the others (p < 0.05). In subgroups D, the release of PDGF-BB, bFGF, and TGF-beta1 depended on ePTFE seeding. A higher amount of these growth factors was released in the prostheses precoated with EC and Matrigel (p < 0.05), and the bromodeoxyuridine labeling index confirmed higher incorporation in this subgroup (p < 0.001). The combined use of locally administered anti-PDGF-BB, bFGF, and TGF-beta1 monoclonal antibodies reduces neointimal hyperplasia formation.
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Affiliation(s)
- Paolo Sapienza
- Department of Surgery Pietro Valdoni, University of Rome La Sapienza, Policlinico Umberto I, Rome, Italy.
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16
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de Mel A, Jell G, Stevens MM, Seifalian AM. Biofunctionalization of biomaterials for accelerated in situ endothelialization: a review. Biomacromolecules 2008; 9:2969-79. [PMID: 18831592 DOI: 10.1021/bm800681k] [Citation(s) in RCA: 245] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The higher patency rates of cardiovascular implants, including vascular bypass grafts, stents, and heart valves are related to their ability to inhibit thrombosis, intimal hyperplasia, and calcification. In native tissue, the endothelium plays a major role in inhibiting these processes. Various bioengineering research strategies thereby aspire to induce endothelialization of graft surfaces either prior to implantation or by accelerating in situ graft endothelialization. This article reviews potential bioresponsive molecular components that can be incorporated into (and/or released from) biomaterial surfaces to obtain accelerated in situ endothelialization of vascular grafts. These molecules could promote in situ endothelialization by the mobilization of endothelial progenitor cells (EPC) from the bone marrow, encouraging cell-specific adhesion (endothelial cells (EC) and/or EPC) to the graft and, once attached, by controlling the proliferation and differentiation of these cells. EC and EPC interactions with the extracellular matrix continue to be a principal source of inspiration for material biofunctionalization, and therefore, the latest developments in understanding these interactions will be discussed.
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Affiliation(s)
- Achala de Mel
- Centre of Nanotechnology, Biomaterials and Tissue Engineering, UCL Division of Surgery & Interventional Science, University College London, London, United Kingdom
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17
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Fischer PE, Fabian TC, Derijk WG, Edwards NM, Decuypere M, Landis RM, Barnard DL, Magnotti LJ, Croce MA. Prosthetic Vascular Conduit in Contaminated Fields: A New Technology to Decrease ePTFE Infections. Am Surg 2008. [DOI: 10.1177/000313480807400611] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Vascular reconstruction using prosthetic materials in contaminated fields can lead to infection, graft loss, and subsequent amputation. We hypothesized that minocycline and rifampin bound to an ePTFE graft using a unique methacrylate technology would provide for resistance from infection and controlled antibiotic elution. Kirby Bauer susceptibility testing was performed on plates overlaid with Staph aureus (SA) and Staph epidermidis (SE) using 6 mm diameter discs of uncoated graft or antibiotic coated graft (ABX). Zones of inhibition (ZIH) were determined after 24 hours. ABX grafts were then placed in a continuous water bath and a recirculating, pulsatile flow device. Susceptibility testing and high performance liquid chromatography with mass spectroscopy was performed to determine graft performance and antibiotic elution rate. ABX grafts had an average ZIH of 35 mm for SA and 44 mm for SE (each P < 0.0001). After the 1 week water bath, the ZIH of the ABX grafts was 23 mm on both the SA and SE plates. The high performance liquid chromatography with mass spectroscopy revealed that after 24 hours, 50 per cent of the antibiotics remained on the graft, and there was a sustained elution for 7 days. Minocycline and rifampin can be bound to ePTFE vascular grafts using a unique methacrylate method. In vitro, the grafts provide a slow elution of antibiotics that provide resistance from infection by SA and SE for up to 2 weeks after graft insertion.
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Affiliation(s)
- Peter E. Fischer
- College of Medicine, Department of Surgery, University of Tennessee Health Science Center, Memphis Tennessee
| | - Timothy C. Fabian
- College of Medicine, Department of Surgery, University of Tennessee Health Science Center, Memphis Tennessee
| | - Waldemar G. Derijk
- College of Dentistry, Biomaterials Division, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Norma M. Edwards
- College of Medicine, Department of Surgery, University of Tennessee Health Science Center, Memphis Tennessee
| | - Michael Decuypere
- College of Medicine, Department of Surgery, University of Tennessee Health Science Center, Memphis Tennessee
| | - Ryan M. Landis
- College of Engineering, Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee
| | - Danielle L. Barnard
- College of Medicine, Department of Surgery, University of Tennessee Health Science Center, Memphis Tennessee
| | - Louis J. Magnotti
- College of Medicine, Department of Surgery, University of Tennessee Health Science Center, Memphis Tennessee
| | - Martin A. Croce
- College of Medicine, Department of Surgery, University of Tennessee Health Science Center, Memphis Tennessee
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18
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Abstract
Atherosclerosis in the form of peripheral arterial disease results in significant morbidity. Surgical treatment options for peripheral arterial disease include angioplasty, endarterectomy, and bypass grafting. For bypass grafting, vein remains the conduit of choice; however, poor quality and limited availability have led to the use of prosthetic materials. Unfortunately, because of a lack of endothelium and compliance mismatch, neointimal hyperplasia develops aggressively, resulting in high failure rates. To improve graft patency, investigators have developed surgical, chemical, and biological graft modifications. This review describes common prosthetic materials, as well as approaches currently in use and under investigation to modify and improve prosthetic conduits for bypass grafting in an effort to improve graft patency rates.
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Affiliation(s)
- Muneera R Kapadia
- Northwestern University Feinberg School of Medicine, Division of Vascular Surgery, Chicago, IL 60611, USA
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19
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Silicone-Based Vascular Prosthesis: Assessment of the Mechanical Properties. Ann Vasc Surg 2008; 22:106-14. [DOI: 10.1016/j.avsg.2007.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Revised: 08/01/2007] [Accepted: 09/14/2007] [Indexed: 11/20/2022]
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Jung MJ, Kwon JS, Park NK, Kim YK, Shim TJ, Jeong IH, Bae JW, Hwang KK, Kim DW, Cho MC. Perivascular Delivery of Rapamycin in Pluronic Gel Inhibits Neointimal Hyperplasia in a Rat Carotid Artery Injury Model, and the Complementary Role of Carotid Arteriography. Korean Circ J 2008. [DOI: 10.4070/kcj.2008.38.2.80] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Mi-Jin Jung
- Department of Pediatrics, Gil Heart Center, Incheon, Korea
| | - Jin-Sook Kwon
- Department of Internal Medicine, College of Medicine, Chonnam National University, Gwangju, Korea
| | - No-Kwan Park
- Division of Cardiology, Department of Internal Medicine, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Yu-Kyung Kim
- Division of Cardiology, Department of Internal Medicine, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Tae Jin Shim
- Division of Cardiology, Department of Internal Medicine, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Il Ha Jeong
- Division of Cardiology, Department of Internal Medicine, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Jang-Whan Bae
- Division of Cardiology, Department of Internal Medicine, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Kyung-Kuk Hwang
- Division of Cardiology, Department of Internal Medicine, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Dong-Woon Kim
- Division of Cardiology, Department of Internal Medicine, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Myeong-Chan Cho
- Division of Cardiology, Department of Internal Medicine, College of Medicine, Chungbuk National University, Cheongju, Korea
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21
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Zilla P, Bezuidenhout D, Human P. Prosthetic vascular grafts: Wrong models, wrong questions and no healing. Biomaterials 2007; 28:5009-27. [PMID: 17688939 DOI: 10.1016/j.biomaterials.2007.07.017] [Citation(s) in RCA: 374] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Accepted: 07/06/2007] [Indexed: 12/20/2022]
Abstract
In humans, prosthetic vascular grafts remain largely without an endothelium, even after decades of implantation. While this shortcoming does not affect the clinical performance of large bore prostheses in aortic or iliac position, it contributes significantly to the high failure rate of small- to medium-sized grafts (SMGs). For decades intensive but largely futile research efforts have been under way to address this issue. In spite of the abundance of previous studies, a broad analysis of biological events dominating the incorporation of vascular grafts was hitherto lacking. By focusing on the three main contemporary graft types, expanded polytetrafluoroethylene (ePTFE), Dacron and Polyurethane (PU), accumulated clinical and experimental experience of almost half a century was available. The main outcome of this broad analysis-supported by our own experience in a senescent non-human primate model-was twofold: Firstly, inappropriate animal models, which addressed scientific questions that missed the point of clinical relevance, were largely used. This led to a situation where the vast majority of investigators unintentionally studied transanastomotic rather than transmural or blood-borne endothelialization. Given the fact that in patients transanastomotic endothelialization (TAE) covers only the immediate perianastomotic region of sometimes very long prostheses, TAE is rather irrelevant in the clinical context. Secondly, transmural endothelialization seems to have a time window of opportunity before a build-up of an adverse microenvironment. In selecting animal models that prematurely terminate this build-up through the early presence of an endothelium, the most significant 'impairment factor' for physiological tissue regeneration in vascular grafts remained ignored. By providing insight into mechanisms and experimental designs which obscured the purpose and scope of several decades of vascular graft studies, future research may better address clinical relevance.
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Affiliation(s)
- Peter Zilla
- Christian Barnard Department of Cardiothoracic Surgery/Cardiovascular Research Unit, University of Cape Town Medical School, Cape Town, South Africa.
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22
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Kapadia MR, Aalami OO, Najjar SF, Jiang Q, Murar J, Lyle B, Eng JW, Kane B, Carroll T, Cahill PM, Kibbe MR. A reproducible porcine ePTFE arterial bypass model for neointimal hyperplasia. J Surg Res 2007; 148:230-7. [PMID: 18028957 DOI: 10.1016/j.jss.2007.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Revised: 07/23/2007] [Accepted: 08/01/2007] [Indexed: 10/22/2022]
Abstract
BACKGROUND Late failure of prosthetic vascular bypass grafting using expanded polytetrafluoroethylene (ePTFE) is secondary to the development of neointimal hyperplasia, most commonly at the distal anastomosis. To develop therapies that can improve upon current prosthetic vascular bypass grafting, a large animal model of prosthetic bypass grafting that results in reproducible neointimal hyperplasia is necessary. METHODS We performed bilateral end-to-side carotid artery bypasses with 6 mm ePTFE in a porcine model (n = 11). We studied graft patency using magnetic resonance angiography (MRA, 3 wk), duplex ultrasonography (4 wk), and digital-subtraction contrast angiography (4 wk). Animals were sacrificed at 4 wk and morphometric analysis was performed. RESULTS Of the 11 animals that underwent surgery, one pig died from respiratory compromise; of the remaining 10, graft patency was 90% at 4 wk. Peak systolic and end diastolic velocities were established for this model using ultrasonography. MRA, ultrasonography, and angiography confirmed graft patency and were complimentary tools to evaluate the grafts. Development of neointimal hyperplasia was reproducible at 4 wk in both the proximal and distal anastomoses (2.5 to 3 mm(2)) of the ePTFE bypass grafts. CONCLUSION We developed a reproducible porcine ePTFE carotid artery bypass model for studying neointimal hyperplasia. Not only does this model allow for the manipulation and evaluation of potential therapies, but patency and neointimal hyperplasia can be easily evaluated by traditional means, such as MRA, ultrasonography, and angiography. This preclinical model is ideal for evaluation of novel therapies in vivo designed to inhibit neointimal hyperplasia following arterial reconstruction with prosthetic bypass grafting.
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Affiliation(s)
- Muneera R Kapadia
- Division of Vascular Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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23
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Kielty CM, Stephan S, Sherratt MJ, Williamson M, Shuttleworth CA. Applying elastic fibre biology in vascular tissue engineering. Philos Trans R Soc Lond B Biol Sci 2007; 362:1293-312. [PMID: 17588872 PMCID: PMC2440413 DOI: 10.1098/rstb.2007.2134] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
For the treatment of vascular disease, the major cause of death in Western society, there is an urgent need for tissue-engineered, biocompatible, small calibre artery substitutes that restore biological function. Vascular tissue engineering of such grafts involves the development of compliant synthetic or biomaterial scaffolds that incorporate vascular cells and extracellular matrix. Elastic fibres are major structural elements of arterial walls that can enhance vascular graft design and patency. In blood vessels, they endow vessels with the critical property of elastic recoil. They also influence vascular cell behaviour through direct interactions and by regulating growth factor activation. This review addresses physiological elastic fibre assembly and contributions to vessel structure and function, and how elastic fibre biology is now being exploited in small diameter vascular graft design.
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Affiliation(s)
- Cay M Kielty
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK.
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25
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Karakayali F, Haberal N, Tufan H, Hasirci N, Basaran O, Sevmis S, Akdur A, Kiziltay A, Haberal M. Evaluation of neointimal hyperplasia on tranilast-coated synthetic vascular grafts: an experimental study. J INVEST SURG 2007; 20:167-73. [PMID: 17613691 DOI: 10.1080/08941930701365101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Tranilast is an antiallergic drug that interferes with proliferation and migration of vascular smooth muscle cell induced by platelet-derived growth factor (PDGF) and transforming growth factor-beta1 (TGF-beta1). We investigated the local effect of tranilast on neointimal hyperplasia using tranilast-coated prosthetic grafts. The inner sides of the thin-walled polytetrafluoroethylene (PTFE) grafts were coated with chitosan and tranilast containing chitosan solution. Wistar albino rats (32) were used in the study. Patches (1 x 2 mm) for vascular grafts were prepared. Three groups were tested: group 1 (n = 12; tranilast coated), group 2 (n = 10; adhesive-only film-layer-coated), and group 3 (n = 10; normal ePTFE patch grafts sutured to the carotid arteries of the rats). Recipient sites of the carotid arteries were excised 4 weeks after surgery. All sections were examined histologically for graft patency, thrombus formation, and neointimal thickness. Expression of PDGF, fibroblast growth factor, and TGF-beta1 on cross-sections of the neointima were evaluated by immunohistochemistry. No significant differences were found regarding mean neointimal thicknesses. PDGF and TGF-beta-1 expressions were significantly lower in group 1. Although a decrease in local effect of tranilast was observed for growth factor expressions at a drug concentration of 0.05 mg/cm(2), a significant reduction in neointimal hyperplasia was not achieved. The coating concentration of 0.05 mg/cm(2) may have been too low to produce an antiproliferative effect. Given our promising results, further studies are recommended and planned using different drug concentrations and time intervals.
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Affiliation(s)
- Feza Karakayali
- Department of General Surgery, Baskent University Faculty of Medicine, Ankara, Turkey
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26
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Fatourou EM, Paraskevas KI, Seifalian AM, Hamilton G, Mikhailidis DP. The role of established and emerging risk factors in peripheral vascular graft occlusion. Expert Opin Pharmacother 2007; 8:901-11. [PMID: 17472536 DOI: 10.1517/14656566.8.7.901] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Several studies have evaluated the association between established as well as emerging vascular risk factors with peripheral graft occlusion. There is evidence for a link between the risk for graft occlusion and total serum cholesterol, low-density lipoprotein cholesterol and triglyceride levels. The overall effect of smoking shows a 2.35-fold increase in risk of graft failure. Studies involving diabetic patients undergoing peripheral bypass may have failed to detect higher occlusion rates, possibly due to increased morbidity and mortality as well as higher amputation rates even if the graft is patent. Both antiplatelet agents and anticoagulation seem to be effective in the prevention of graft occlusion. Unconvincing data have been published with regards to the effect of hypertension on graft patency. Emerging factors such as fibrinogen, lipoprotein (a), C-reactive protein and homocysteine levels should also be considered when assessing the risk of graft occlusion. More research is needed to prevent graft occlusion due to the obvious clinical relevance, quality of life and cost issues.
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Affiliation(s)
- E M Fatourou
- Department of Clinical Biochemistry, Royal Free Hospital and Royal Free University College Medical School, London, UK
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27
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Edwards NM, Claridge JA, Shell DH, Handorf CR, Croce MA, Fabian TC. The Effect of Bacterial Contamination on Neointimal Hyperplasia in Vascular Grafts. Am Surg 2006. [DOI: 10.1177/000313480607201205] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Neointimal hyperplasia (NH) is the most significant contributing factor to long-term vascular graft failure. Inflammation is known to be important in its development; however, the role of bacterial infection is unclear. We examined the effect of contamination with common organisms on the development of NH in expanded polytetrafluoroethylene grafts. Thirty adult pigs were randomized into one of four groups: no infection, contamination with Staphylococcus aureus, mucin-producing Staphylococcus epidermidis, or Pseudomonas aeruginosa. An expanded polytetrafluoroethylene graft (6 mm x 3 cm) was placed as a common iliac artery interposition graft and was inoculated with 1–2 x 108 of the selected organism before closure. Grafts were explanted 6 weeks postoperatively. Microbiologic, histological, and morphometric evaluations were performed. All grafts were patent at the time of euthanasia. The mean areas of NH were 5.45 mm2 in sterile grafts, 8.36 mm2 in S. aureus, 7.63 mm2 in S. epidermidis, and 11.52 mm2 in P. aeruginosa grafts. Comparison of means via analysis of variance showed that P. aeruginosa grafts had significantly higher formation of NH than sterile grafts (P = 0.025). NH production in infected grafts appears to be organism specific and is significantly higher with P. aeruginosa than common Gram-positive organisms. Increased NH from subclinical infection may be a significant factor contributing to late graft failures.
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Affiliation(s)
- Norma M. Edwards
- Department of Surgery, University of Tennessee Health Science Center, Memphis, Tennessee and
| | - Jeffrey A. Claridge
- MetroHealth Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Dan H. Shell
- Department of Surgery, University of Tennessee Health Science Center, Memphis, Tennessee and
| | - Charles R. Handorf
- Department of Surgery, University of Tennessee Health Science Center, Memphis, Tennessee and
| | - Martin A. Croce
- Department of Surgery, University of Tennessee Health Science Center, Memphis, Tennessee and
| | - Timothy C. Fabian
- Department of Surgery, University of Tennessee Health Science Center, Memphis, Tennessee and
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28
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Bünger CM, Grabow N, Kröger C, Lorenzen B, Hauenstein K, Goosmann M, Schmitz KP, Kreutzer HJ, Lootz D, Ince H, Nienaber CA, Klar E, Schareck W, Sternberg K. Iliac Anastomotic Stenting With a Sirolimus-Eluting Biodegradable Poly-L-Lactide Stent: A Preliminary Study After 6 Weeks. J Endovasc Ther 2006; 13:630-9. [PMID: 17042669 DOI: 10.1583/06-1899r.1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE To assess technical feasibility and biocompatibility of a new biodegradable sirolimus-eluting poly-L-lactide (PLLA) vascular anastomotic stent. METHODS A polytetrafluoroethylene bifurcated graft was implanted in 9 pigs through a midline abdominal incision. After transverse graft limb incision, 6 unloaded PLLAs, 6 sirolimus-loaded PLLAs, and 6 unloaded stainless steel (316L) stents were randomly implanted at both iliac anastomotic sites. Stents were deployed with a 6-mm balloon under direct vision without the use of angiography. Prior to sacrifice after 6 weeks, contrast-enhanced computed tomography (CT) was performed to determine patency of the target vessels. Stented segments were surgically explanted and processed for histology to measure the mean luminal diameter and intimal thickness and to assign vascular injury and inflammation scores. RESULTS No animals were lost during the study period. All stented graft limbs were patent on CT and histology. At the anastomotic sites and iliac arteries, the mean luminal diameter of SIR-PLLA stents (4.11+/-0.15 and 4.08+/-0.13 mm, respectively) were comparable to metal stents (4.23+/-0.35 and 4.21+/-0.26 mm, respectively), but significantly higher compared to unloaded PLLA stents [3.32+/-0.56 mm (p<0.001) and 3.29+/-0.39 mm (p=0.013), respectively]. At the iliac arteries, the mean intimal thickness was significantly lower with SIR-PLLA stents (0.09+/-0.02 mm) compared to unloaded PLLA stents (0.31+/-0.15 mm, p<0.001) and metal stents (0.19+/-0.04 mm, p=0.004). Vascular injury scores demonstrated only mild vascular trauma for all stents (SIR-PLLA: 0.42+/-0.63, PLLA: 0.51+/-0.62, metal: 0.50+/-0.62). Only mild inflammatory reaction was noted around SIR-PLLA stent struts (1.14+/-0.46), which was comparable to metal stents (1.27+/-0.45) but significantly lower than PLLA stents (1.79+/-0.56, p<0.001). CONCLUSION SIR-PLLA stents showed comparable luminal diameter compared to metal stents, so incorporating sirolimus could reduce the inflammatory and neointimal response to PLLA stents. These findings need to be assessed with longer follow-up to confirm maintenance of efficacy.
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29
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Terry CM, Blumenthal DK, Sikharam S, Li L, Kuji T, Kern SE, Cheung AK. Evaluation of histological techniques for quantifying haemodialysis arteriovenous (AV) graft hyperplasia. Nephrol Dial Transplant 2006; 21:3172-9. [PMID: 16957014 DOI: 10.1093/ndt/gfl366] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Assessing treatment efficacies for preventing haemodialysis arteriovenous (AV) graft stenosis requires a reproducible method for quantifying intimal hyperplasia. We identified sources of variability in three histological methods for assessing hyperplasia in a porcine AV graft model. METHODS Carotid-jugular synthetic grafts were placed in pigs. After explantation at 3-6 weeks, the tissue was stained with haematoxylin and eosin (H&E), Masson's trichrome or elastic tissue Van Gieson (EVG) stains and examined histologically. Hyperplasia at the anastomosis of 14 grafts was quantified using three different methods, each by four blinded observers. These methods were visual scoring, ratio of intima-to-media surface area (I/M ratio), and ratio of intra-graft hyperplasia to graft surface area (H/G ratio) at the graft-vessel interface. RESULTS The EVG stain proved superior in delineation of the elastic lamina yet quantification of the intimal and medial layers was still often difficult. This is illustrated by the greater inter-observer median coefficient of variances (CV) found using the I/M ratio method (intimal area CV=13.7%; medial area CV=32.7%; I/M ratio CV=44.0%) than with the H/G method (intra-graft hyperplasia area CV=7.3%, graft area CV=5.3%; H/G ratio CV=6.9%) or by visual scoring (CV=26.8%). The H/G ratios correlated positively with visual scores (r=0.941; P=0.0007; n=14) and the I/M ratio (r=0.719; P=0.0095; n=14). While hyperplasia was seen in both native vessel and graft lumen, in only one of the 14 anastomoses was the degree of hyperplasia greater in the native vessel than in the graft lumen, suggesting that the degree of hyperplasia occurring within the graft lumen predicted the total hyperplasia around the anastomosis. CONCLUSIONS The H/G method for assessing hyperplasia is preferred in a porcine model of AV graft because it is quantitative, less variable and does not require the delineation of the elastic lamina, although it infrequently underestimates the total hyperplasia that occurs.
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Affiliation(s)
- Christi M Terry
- Department of Medicine, University of Utah and Medical Service, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, UT 84112-5350, USA.
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30
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Polymers for tissue engineering, medical devices, and regenerative medicine. Concise general review of recent studies. POLYM ADVAN TECHNOL 2006. [DOI: 10.1002/pat.729] [Citation(s) in RCA: 291] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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