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KUZU TE. Comparison tensile strength of different sutur materials. CUMHURIYET DENTAL JOURNAL 2022. [DOI: 10.7126/cumudj.978167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Conn G, Kidane AG, Punshon G, Kannan RY, Hamilton G, Seifalian AM. Is there an alternative to systemic anticoagulation, as related to interventional biomedical devices? Expert Rev Med Devices 2014; 3:245-61. [PMID: 16515390 DOI: 10.1586/17434440.3.2.245] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
To reduce the toxic effects, related clinical problems and complications such as bleeding disorders associated with systemic anticoagulation, it has been hypothesized that by coating the surfaces of medical devices, such as stents, bypass grafts, extracorporeal circuits, guide wires and catheters, there will be a significant reduction in the requirement for systemic anticoagulation or, ideally, it will no longer be necessary. However, current coating processes, even covalent ones, still result in leaching followed by reduced functionality. Alternative anticoagulants and related antiplatelet agents have been used for improvement in terms of reduced restenosis, intimal hyperphasia and device failure. This review focuses on existing heparinization processes, their application in clinical devices and the updated list of alternatives to heparinization in order to obtain a broad overview, it then highlights, in particular, the future possibilities of using heparin and related moieties to tissue engineer scaffolds.
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Affiliation(s)
- Gemma Conn
- Biomaterials & Tissue Engineering Centre, Academic Division of Surgical and Interventional Sciences, University College London, Rowland Hill Street, Hampstead, London NW3 2PF, UK
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Abstract
With the high occurrence of cardiovascular disease and increasing numbers of patients requiring vascular access, there is a significant need for small-diameter (<6 mm inner diameter) vascular graft that can provide long-term patency. Despite the technological improvements, restenosis and graft thrombosis continue to hamper the success of the implants. Vascular tissue engineering is a new field that has undergone enormous growth over the last decade and has proposed valid solutions for blood vessels repair. The goal of vascular tissue engineering is to produce neovessels and neoorgan tissue from autologous cells using a biodegradable polymer as a scaffold. The most important advantage of tissue-engineered implants is that these tissues can grow, remodel, rebuild, and respond to injury. This review describes the development of polymeric materials over the years and current tissue engineering strategies for the improvement of vascular conduits.
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Lord MS, Yu W, Cheng B, Simmons A, Poole-Warren L, Whitelock JM. The modulation of platelet and endothelial cell adhesion to vascular graft materials by perlecan. Biomaterials 2009; 30:4898-906. [PMID: 19540587 DOI: 10.1016/j.biomaterials.2009.05.063] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Accepted: 05/25/2009] [Indexed: 10/20/2022]
Abstract
Controlled neo-endothelialisation is critical to the patency of small diameter vascular grafts. Endothelialisation and platelet adhesion to purified endothelial cell-derived perlecan, the major heparan sulfate (HS) proteoglycan in basement membranes, were investigated using in vivo and in vitro assays. Expanded polytetrafluoroethylene (ePTFE) vascular grafts were coated with perlecan and tested in an ovine carotid interposition model for a period of 6 weeks and assessed using light and scanning microscopy. Enhanced endothelial cell growth and reduced platelet adhesion were observed on the perlecan coated grafts when compared to uncoated controls implanted in the same sheep (n=5). Perlecan was also found to stimulate endothelial cell proliferation in vitro over a period of 6 days in the presence of plasma proteins and fibroblastic growth factor 2 (FGF-2), however in the absence of FGF-2 endothelial cell growth could not be maintained during this period. Perlecan was found to be anti-adhesive for platelets, however after removal of the HS chains attached to perlecan, platelet adhesion and aggregation were supported. These results suggest a role for HS chains of perlecan in improving graft patency by selectively promoting endothelial cell proliferation while modulating platelet adhesion.
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Affiliation(s)
- Megan S Lord
- Graduate School of Biomedical Engineering, The University of New South Wales, Gate 11, Botany St, Randwick, Sydney, NSW 2052, Australia.
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Ferreira P, Coelho JFJ, Gil MH. Development of a new photocrosslinkable biodegradable bioadhesive. Int J Pharm 2007; 352:172-81. [PMID: 18065171 DOI: 10.1016/j.ijpharm.2007.10.026] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 10/15/2007] [Accepted: 10/22/2007] [Indexed: 11/25/2022]
Abstract
Adhesives provide a needle-free method of wound closure and do not require local anaesthetics. Polymeric adhesives have been used for about 3 decades for joining several tissues of the organism. Also, they can accomplish other tasks, such as haemostasis and the ability to seal air leakages and have the potential to serve as delivery systems. PCL was modified with 2-isocyanatoethylmethacrylate to form a macromer that was crosslinked via UV irradiation using Irgacure 2959 by CIBA as the photoinitiating agent. The characterization of the materials was accomplished by: attenuated total reflectance-Fourier transform infrared (ATR-FTIR), swelling capacity determination, evaluation of adhesive capacity (by reaction with aminated substrates) and determination of surface energy by contact angle measurement. Thermal characterization of the adhesive was performed by dynamical mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA). The morphology of PCL networks was observed using scanning electron microscopy (SEM) both after crosslinking process and following biodegradation in human plasma. The haemocompatibility of the membranes was also evaluated by thrombosis and haemolysis tests.
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Affiliation(s)
- P Ferreira
- Department of Chemical Engineering, University of Coimbra, Rua Sílvio Lima, Polo II, 3030-790 Coimbra, Portugal.
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Walpoth BH, Zammaretti P, Cikirikcioglu M, Khabiri E, Djebaili MK, Pache JC, Tille JC, Aggoun Y, Morel D, Kalangos A, Hubbell JA, Zisch AH. Enhanced intimal thickening of expanded polytetrafluoroethylene grafts coated with fibrin or fibrin-releasing vascular endothelial growth factor in the pig carotid artery interposition model. J Thorac Cardiovasc Surg 2007; 133:1163-70. [PMID: 17467424 DOI: 10.1016/j.jtcvs.2007.01.029] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2006] [Revised: 08/24/2006] [Accepted: 09/19/2006] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Intimal hyperplasia and surface thrombogenicity are major factors in the high failure rate of synthetic small-diameter bypass grafts. Vascular endothelial growth factor is a potent stimulus for endothelial growth, and its provision in a fibrin matrix coating at the luminal graft surface may hold a key to spontaneous graft endothelialization and improved graft patency. METHODS Pigs underwent bilateral carotid artery interposition of expanded polytetrafluoroethylene grafts either impregnated with fibrin (n = 11)--engineered to locally release vascular endothelial growth factor121 (vascular endothelial growth factor-fibrin; n = 11)--or left uncoated (n = 12). Graft patency was assessed by quantitative carotid angiography followed by graft histomorphometry at the 1-month experimental end point. RESULTS Patency rates were not significantly different between study groups. Grafts coated with fibrin or vascular endothelial growth factor-fibrin exhibited significantly increased angiographic narrowing at the proximal anastomosis (for both P < .05 vs uncoated) and no difference at the distal anastomosis and the grafts' middle. Histological analysis showed 80% to 90% endothelial coverage and buildup of intima throughout the lengths of all grafts. Examination of the grafts' midportion revealed significantly enlarged neointimal layers of smooth muscle actin-positive cells in grafts coated with vascular endothelial growth factor-fibrin (242 +/- 47 microm2/micron) and fibrin (177 +/- 41 microm2/micron), compared with uncoated grafts (131 +/- 39 microm2/micron) (for both P < .05 vs uncoated). This thickening could not be explained by enhanced inflammation or vessel wall angiogenesis, which were minimal at the experimental end point. CONCLUSIONS Fibrin and vascular endothelial growth factor produced effects deleterious to graft healing, by increasing the narrowing at proximal anastomosis and neointimal growth beyond that seen in uncoated grafts. It may reflect direct activation by exogenous vascular endothelial growth factor of vascular smooth muscle cells.
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Affiliation(s)
- Beat H Walpoth
- Clinic of Cardiovascular Surgery, University of Geneva, Switzerland.
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Sae-Lim V, Ong WY, Li Z, Neo J. The effect of basic fibroblast growth factor on delayed-replanted monkey teeth. J Periodontol 2005; 75:1570-8. [PMID: 15732856 DOI: 10.1902/jop.2004.75.12.1570] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Basic fibroblast growth factor (bFGF; FGF-2) has been reported to facilitate wound healing and periodontal regeneration in experimental alveolar bone defects. The purpose of this study was to evaluate histologically the effect of topically applied bFGF with or without fibrin glue on delayed-replanted monkey teeth prone to replacement resorption. METHODS Forty-five roots from five monkeys were endodontically treated aseptically and then extracted as atraumatically as possible. Ten negative control roots were replanted immediately, while 12 positive control roots were allowed to bench dry for 1 hour prior to replantation, both without further treatment. Roots in the two experimental groups were bench dried for 1 hour, rinsed with saline, and then replanted into sockets filled with bFGF with (11 roots) or without (12 roots) fibrin glue. After 12 weeks, histological sections were prepared and evaluated according to morphometric analysis as complete healing or unfavorable healing composed of inflammatory resorption and replacement resorption. RESULTS Kruskal-Wallis and Mann-Whitney U tests showed teeth in the negative control group to have significantly higher complete healing (98.88% +/- 2.30%) and significantly lower unfavorable healing (1.12% +/- 2.30%) than the positive control group and the experimental groups. bFGF/fibrin glue group showed higher occurrence of complete healing (39.06% +/- 41.62%) compared to the bFGF group (25.28% +/- 28.85%) and the positive control group (16.58% +/- 19.60%), although the differences were not significant. Comparing the complete and unfavorable healing, there was no significant difference in the bFGF/fibrin glue group (P = 0.47), but the differences were significant in the other groups (P < 0.05). CONCLUSION Topical application of bFGF with fibrin glue showed an insignificantly higher occurrence of complete healing in delayed-replanted monkey teeth.
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Affiliation(s)
- Varawan Sae-Lim
- Department of Restorative Dentistry, Faculty of Dentistry, National University of Singapore, Republic of Singapore.
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Kidane AG, Salacinski H, Tiwari A, Bruckdorfer KR, Seifalian AM. Anticoagulant and antiplatelet agents: their clinical and device application(s) together with usages to engineer surfaces. Biomacromolecules 2005; 5:798-813. [PMID: 15132664 DOI: 10.1021/bm0344553] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An essential aspect of the treatment of patients with cardiovascular disease is the use of anticoagulant and antiplatelet agents for the prevention of further ischaemic events and vascular death resulting from thrombosis. Aspirin and heparin have been the standard therapy for the management of such conditions to date. Recently, numerous more potent platelet inhibitors together with anticoagulant agents have been developed and tested in randomized clinical trials. This article reviews the current state of the art of antiplatelet and anticoagulant therapy in light of its potential clinical efficacy. It then focuses on the usages of these agents in order to improve the performance of clinical devices such as balloon catheters, coronary stents, and femoropopliteal bypass grafting and extra corporeal circuits for cardiopulmonary bypass. The article then goes on to look at the usage of these agents more specifically heparin, heparan, hirudin, and coumarin in the development of more biocompatible scaffolds for tissue engineering.
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Affiliation(s)
- Asmeret G Kidane
- University Department of Surgery, Royal Free and University College Medical School, University College London, Royal Free Hospital, London NW3 2QG, United Kingdom
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Minato N, Shimokawa T, Katayama Y, Yamada N, Sakaguchi M, Itoh M. New application method of fibrin glue for more effective hemostasis in cardiovascular surgery. ACTA ACUST UNITED AC 2004; 52:361-6. [PMID: 15384709 DOI: 10.1007/s11748-004-0011-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE This study was performed to determine the most effective application method of fibrin glue as a hemostatic sealant in cardiovascular surgery. METHODS The effectiveness of fibrin glue as a hemostatic sealant was compared between 4 methods of application; dripping, spray, spray-and-rub, and rub-and-spray methods. I. In vitro 'burst pressure' was measured in fibrin glue-sealed needle holes of polytetrafluoroethylene (PTFE) graft in each method. II. Fibrin glue-sealed needle holes of PTFE grafts implanted between an abdominal aorta and iliac arteries of a pig was microscopically examined to determine the effectiveness of fibrin glue sealing in each method. RESULTS I. Burst pressures were 24.1 +/- 7.9 mmHg in dripping, 98.1 +/- 35.4 mmHg in spray, 140.8 +/- 34.8 mmHg in spray-and-rub and 206.7 +/- 26.1 mmHg in rub-and-spray method (statistically significant, p<0.01, between each method). II. Microscopically, no fibrin glue remained on the external surface of the PTFE graft in the dripping method. Fibrin glue plugged 1/3 or 2/3 of the depth of the needle hole in the spray method and spray-and-rub methods respectively. In the rub-and-spray method, fibrin glue covered the needle hole over the external surface of the graft, completely plugged the needle hole to its whole depth, leaving no spaces where blood came into the needle hole. CONCLUSION The rub-and-spray method of fibrin glue application revealed the strongest sealing and hemostatic effects, and can be safely and effectively used for hemostasis in cardiovascular surgery that requires systemic heparinization or prolonged extracorporeal circulation.
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Affiliation(s)
- Naoki Minato
- Department of Thoracic and Cardiovascular Surgery, Fukuoka Tokushukai Hospital, Kasuga, Fukuoka, Japan
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Abstract
The development of new therapeutic approaches that aim to help the body exert its natural mechanisms for vascularized tissue growth (therapeutic angiogenesis) has become one of the most active areas of tissue engineering. Through basic research, several growth factor families and cytokines that are capable to induce physiological blood vessel formation have been identified. Indeed, preclinical and clinical investigations have indicated that therapeutic administration of angiogenic factors, such as the prototypic vascular endothelial growth factor (VEGF) or basic fibroblast growth factor (bFGF), to sites of ischemia in the heart or the limb can improve regional blood flow. For new and lasting tissue vascularization, prolonged tissue exposure to these factors could be critical. Furthermore, as shown for VEGF, dosage must be tightly controlled, as excess amounts of VEGF can cause severe vascular leakage and hypotension. This review emphasizes natural and synthetic polymer matrices with respect to their development as vehicles for local and controlled delivery of angiogenic proteins, such as VEGF and bFGF, and their clinical applicability. In the dawn of experimental vascular engineering, new biomaterial schemes for clinical growth factor administration that take better account of biological principles of angiogenic growth factor function and the cell biological basis necessary to produce functional vasculature are evolving. Alongside their base function as protective embedment for angiogenic growth factors, these new classes of bioactive polymers are engineered with additional functionalities that better preserve growth factor activity and more closely mimic the in vivo release mechanisms and profiles of angiogenic growth factors from the extracellular matrix (ECM). Consequently, the preparation of both natural or completely synthetic materials with biological characteristics of the ECM has become central to many tissue engineering approaches that aim to deliver growth factors in a therapeutically efficient mode. Another promising venue to improve angiogenic performance is presented by biomaterials that allow sequential delivery of growth factors with complementary roles in blood vessel initiation and stabilization.
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Affiliation(s)
- Andreas H Zisch
- Institute for Biomedical Engineering and Department of Materials Science, Swiss Federal Institute of Technology Zurich (ETHZ), Moussonstrasse 18, 8044 Zurich, Switzerland.
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Zamora PO, Tsang R, Peña LA, Osaki S, Som P. Local delivery of basic fibroblast growth factor (bFGF) using adsorbed silyl-heparin, benzyl-bis(dimethylsilylmethyl)oxycarbamoyl-heparin. Bioconjug Chem 2002; 13:920-6. [PMID: 12236772 DOI: 10.1021/bc0155216] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A growth factor delivery system was developed that is based on the use of silyl-heparin, a chemically modified analogue of heparin. The silyl-heparin was adsorbed onto surfaces by hydrophobic interaction via the prosthetic unit and can then be used as a solid-phase adsorbent for bFGF. All the coating steps were performed by adsorption, a process that allowed preparation of surfaces by immersion or "dip-coating". In this study a series of silyl-heparins were synthesized and each of the analogues found to function similar to unmodified heparin relative to their binding of antithrombin III and also the binding of bFGF. The silyl-heparins were found to be adsorbed onto a wide variety of substrates including polystyrene and lactide:glycolide copolymer. Enzyme-linked immumosorbant assay (ELISA) was used to establish that bFGF was readily bound to surface adsorbed silyl-heparin, and that the amount bound was directly related to amount offered for binding. Once adsorbed the silyl-heparin/FGF was able to induce capillary tube formation of endothelial cells and to increase the growth of endothelial cells. When coated onto suture material and implanted in muscle, the FGF/silyl-heparin coating caused an increased density of mesenchymal cells in the area of the implant. This coating method could prove to be useful in a number of tissue engineering applications for the local delivery of FGF and other growth factors.
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Affiliation(s)
- Paul O Zamora
- Biosurface Engineering Technologies, Inc., 387 Technology Drive, College Park, Maryland 20742-3371, USA.
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Abstract
Tissue adhesives are common adjuncts in surgical practice. Fibrin sealants are the most prevalent adhesives today. Recently, new adhesives have been approved for use in the United States, including cyanoacrylates, albumin-based compounds, collagen-based compounds, glutaraldehyde glues, and hydrogels. This review summarizes all the available tissue adhesives, focusing on their current and prospective indications in the clinical forum.
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Affiliation(s)
- T B Reece
- Department of Surgery, Division of Thoracic and Cardiovascular Surgery, The University of Virginia Health Sciences Center, Box 801359, Charlottesville, VA 22908, USA.
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Fei X, Tan BK, Lee ST, Foo CL, Sun DF, Aw SE. Effect of fibrin glue coating on the formation of new cartilage. Transplant Proc 2000; 32:210-7. [PMID: 10701027 DOI: 10.1016/s0041-1345(99)00939-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
- X Fei
- Department of Clinical Research, Singapore General Hospital, Singapore
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Schense JC, Hubbell JA. Cross-linking exogenous bifunctional peptides into fibrin gels with factor XIIIa. Bioconjug Chem 1999; 10:75-81. [PMID: 9893967 DOI: 10.1021/bc9800769] [Citation(s) in RCA: 268] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Bi-domain peptides with a factor XIIIa substrate in one domain and a bioactive peptide in another domain were covalently incorporated into fibrin gels during coagulation through the action of the transglutaminase factor XIIIa. The cross-linking characteristics were determined for two bi-domain peptides with factor XIIIa substrates based on fibrinogen, dYRGDTIGEGQQHHLGG-NH2, and dLRGDGAKDV-NH2, as well as one bi-domain peptide with a substrate sequence based on alpha2-plasmin inhibitor, dLNQEQVSPLRGD-NH2, and another with a nonbiological, oligolysine substrate, dLRGDKKKKG-NH2 (substrate domains in italic). Each of these peptides was able to cross-link into the fibrin gels during coagulation, with the peptide containing the factor XIIIa substrate based on alpha2-plasmin inhibitor being incorporated at levels in excess of 8 mol/mol fibrinogen. The structural characteristics of these peptide-modified gels proved to be the same as those for a native fibrin gel. The bioactivity of the incorporated active factors was tested in a neuronal culture model with day 8 chicken dorsal root ganglia using two bioactive sequences, RGD and DGEA, and one inactive control sequence, RDG. Each of these peptides influenced the extension of neurites from the ganglia as expected, indicating that the incorporated factors retained their activity. With the use of soluble competitive inhibitors, it was shown that this effect was due to the covalently incorporated peptides. Through exploiting the role of factor XIIIa in coagulation, we have developed a method by which to impart the character of nonfibrin proteins, such as extracellular matrix proteins, to fibrin, a biological material with many potential therapeutic and academic applications.
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Affiliation(s)
- J C Schense
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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