Development of a Compliant Electrospun Polyurethane Vascular Graft

2010 ◽  
Author(s):  
Andrew Whitton ◽  
David J. Flint ◽  
Richard A. Black
Keyword(s):  
Vascular Graft ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Immunofluorescence Analysis ◽  
Aortic Smooth Muscle ◽  
Contractile Phenotype ◽  
A Cell ◽  
Substitute Material ◽  
Cells Cultured

Synthetic vascular grafts are an integral tool in vascular surgery. However, the consistent failure of small diameter grafts is one of the main limitations of these devices. For this reason electrospun polyurethane has been investigated for its suitability as a vascular substitute material in this present study. Aligned and random mesh electrospun polyurethane materials were produced and analysed in vitro by investigating the effect of using both materials as a substrate for the culture of human aortic smooth muscle cells. Immunofluorescence analysis showed that cells cultured on electrospun polyurethane maintained a contractile phenotype to a much greater extent than those cultured on cast polyurethane membranes. This contractile phenotype is associated with the state in which a cell would normally reside in a healthy vessel, suggesting that electrospun polyurethane may provide a suitable vascular substitute material.

scholarly journals Comparative Evaluation on Impacts of Fibronectin, Heparin–Chitosan, and Albumin Coating of Bacterial Nanocellulose Small-Diameter Vascular Grafts on Endothelialization In Vitro

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1952
Author(s):  
Max Wacker ◽  
Jan Riedel ◽  
Heike Walles ◽  
Maximilian Scherner ◽  
George Awad ◽  
...  
Keyword(s):  
Low Density Lipoprotein ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Density Lipoprotein ◽  
Human Albumin ◽  
Water Soluble ◽  
Bacterial Nanocellulose ◽  
Functionally Impaired ◽  
Small Diameter Vascular Grafts

In this study, we contrast the impacts of surface coating bacterial nanocellulose small-diameter vascular grafts (BNC-SDVGs) with human albumin, fibronectin, or heparin–chitosan upon endothelialization with human saphenous vein endothelial cells (VEC) or endothelial progenitor cells (EPC) in vitro. In one scenario, coated grafts were cut into 2D circular patches for static colonization of a defined inner surface area; in another scenario, they were mounted on a customized bioreactor and subsequently perfused for cell seeding. We evaluated the colonization by emerging metabolic activity and the preservation of endothelial functionality by water soluble tetrazolium salts (WST-1), acetylated low-density lipoprotein (AcLDL) uptake assays, and immune fluorescence staining. Uncoated BNC scaffolds served as controls. The fibronectin coating significantly promoted adhesion and growth of VECs and EPCs, while albumin only promoted adhesion of VECs, but here, the cells were functionally impaired as indicated by missing AcLDL uptake. The heparin–chitosan coating led to significantly improved adhesion of EPCs, but not VECs. In summary, both fibronectin and heparin–chitosan coatings could beneficially impact the endothelialization of BNC-SDVGs and might therefore represent promising approaches to help improve the longevity and reduce the thrombogenicity of BNC-SDVGs in the future.

scholarly journals Engineering the Composition of Microfibers to Enhance the Remodeling of a Cell-Free Vascular Graft

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1613
Author(s):  
Fang Huang ◽  
Yu-Fang Hsieh ◽  
Xuefeng Qiu ◽  
Shyam Patel ◽  
Song Li
Keyword(s):  
Vascular Graft ◽  
Animal Studies ◽  
Vascular Grafts ◽  
Cell Infiltration ◽  
Tubular Scaffold ◽  
Base Polymer ◽  
A Cell ◽  
Scaffold Materials ◽  
Stromal Cell Derived Factor ◽  
Technology Blending

The remodeling of vascular grafts is critical for blood vessel regeneration. However, most scaffold materials have limited cell infiltration. In this study, we designed and fabricated a scaffold that incorporates a fast-degrading polymer polydioxanone (PDO) into the microfibrous structure by means of electrospinning technology. Blending PDO with base polymer decreases the density of electrospun microfibers yet did not compromise the mechanical and structural properties of the scaffold, and effectively enhanced cell infiltration. We then used this technique to fabricate a tubular scaffold with heparin conjugated to the surface to suppress thrombosis, and the construct was implanted into the carotid artery as a vascular graft in animal studies. This graft significantly promoted cell infiltration, and the biochemical cues such as immobilized stromal cell-derived factor-1α further enhanced cell recruitment and the long-term patency of the grafts. This work provides an approach to optimize the microfeatures of vascular grafts, and will have broad applications in scaffold design and fabrication for regenerative engineering.

scholarly journals Review: Tissue Engineering of Small-Diameter Vascular Grafts and Their In Vivo Evaluation in Large Animals and Humans

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 713
Author(s):  
Shu Fang ◽  
Ditte Gry Ellman ◽  
Ditte Caroline Andersen
Keyword(s):  
Animal Models ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Large Animal ◽  
Large Animal Models ◽  
Graft Outcome ◽  
Limited Success ◽  
Large Animals

To date, a wide range of materials, from synthetic to natural or a mixture of these, has been explored, modified, and examined as small-diameter tissue-engineered vascular grafts (SD-TEVGs) for tissue regeneration either in vitro or in vivo. However, very limited success has been achieved due to mechanical failure, thrombogenicity or intimal hyperplasia, and improvements of the SD-TEVG design are thus required. Here, in vivo studies investigating novel and relative long (10 times of the inner diameter) SD-TEVGs in large animal models and humans are identified and discussed, with emphasis on graft outcome based on model- and graft-related conditions. Only a few types of synthetic polymer-based SD-TEVGs have been evaluated in large-animal models and reflect limited success. However, some polymers, such as polycaprolactone (PCL), show favorable biocompatibility and potential to be further modified and improved in the form of hybrid grafts. Natural polymer- and cell-secreted extracellular matrix (ECM)-based SD-TEVGs tested in large animals still fail due to a weak strength or thrombogenicity. Similarly, native ECM-based SD-TEVGs and in-vitro-developed hybrid SD-TEVGs that contain xenogeneic molecules or matrix seem related to a harmful graft outcome. In contrast, allogeneic native ECM-based SD-TEVGs, in-vitro-developed hybrid SD-TEVGs with allogeneic banked human cells or isolated autologous stem cells, and in-body tissue architecture (IBTA)-based SD-TEVGs seem to be promising for the future, since they are suitable in dimension, mechanical strength, biocompatibility, and availability.

scholarly journals In vitro hemo- and cytocompatibility of bacterial nanocelluose small diameter vascular grafts: Impact of fabrication and surface characteristics.

PLoS ONE ◽  
2020 ◽  
Vol 15 (6) ◽  
pp. e0235168 ◽  
Author(s):  
Max Wacker ◽  
Viktoria Kießwetter ◽  
Ingo Slottosch ◽  
George Awad ◽  
Adnana Paunel-Görgülü ◽  
...  
Keyword(s):  
Vascular Grafts ◽  
Small Diameter ◽  
Surface Characteristics ◽  
Small Diameter Vascular Grafts

BIOSPUN VASCULAR GRAFTS: IN VIVO EVALUATION OF A NOVEL SMALL‐DIAMETER BIOACTIVE NANOFIBROUS VASCULAR GRAFT FOR ARTERIAL RECONSTRUCTION

2008 ◽  
Vol 22 (S2) ◽  
pp. 605-605
Author(s):  
Mauricio Antonio Contreras ◽  
Mathew Douglas Phaneuf ◽  
Shengqian Wu ◽  
Martin J. Bide ◽  
Frank W. LoGerfo
Keyword(s):  
Vascular Graft ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Arterial Reconstruction ◽  
In Vivo Evaluation

scholarly journals BIODEGRADABLE VASCULAR GRAFT MODIFIED BY RGD-PEPTIDES: EXPERIMENTAL RESEARCH

2019 ◽  
Vol 34 (2) ◽  
pp. 129-137
Author(s):  
E. O. Krivkina ◽  
V. N. Silnikov ◽  
A. V. Mironov ◽  
E. A. Velikanova ◽  
E. A. Senokosova ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Internal Surface ◽  
Mechanical Tests ◽  
Laboratory Animals ◽  
Rgd Peptides ◽  
Peptide Modification

Research goals. To study the effectiveness of RGD-peptide modification of the small-diameter biodegradable vascular grafts depending on the type of a linker and RGD configuration.Material and Methods. Tubular scaffolds with a diameter of 1.5 and 4.0 mm were produced by electrospinning from polyhydroxybutyrate/valerate (PHBV) and polycaprolactone (PCL). The PHBV/PCL grafts were modified with RGD peptides. In vitro experiments showed the degree of erythrocyte hemolysis and adhesion of the platelets and endothelial cells when in contact with a modified surface. The physico-mechanical properties and the structure of graft surface were studied before and after modification. The PHBV/PCL and PHBV/PCL/RGD vascular grafts were implanted into the abdominal aorta of rats for the periods of 1 and 3 months. Explant samples were studied using confocal microscopy and histological methods.Results. The results of physical and mechanical tests showed a significant decrease in the strength properties of the PHBV/PCL/RGD grafts relative to the unmodified analogs. A significant increase in platelet aggregation was found in the modified grafts. The level of adhesion of the endothelial cells on the modified surfaces was higher than that on the unmodified surfaces. Shortterm implantation of the grafts for 1 and 3 months showed that the modified grafts had higher patency and a less tendency to calcification compared with the unmodified grafts. Immunofluorescence study demonstrated the significant superiority of the modified vascular grafts in terms of stimulating the formation of a mature endothelial monolayer. A longer linker of 4,7,10-trioxa-1,13-tridecane diamine was found to increase the bioavailability of RGD peptides; the use of RGDK and c[RGDFK] for surface modification of the grafts stimulated early endothelialization of the internal surface of the implants and reduced the prosthetic wall calcification tendency, which together increased the patency of the implanted grafts.Conclusion. In short-term implantation of biodegradable vascular grafts modified with RGD peptides, the grafts with RGDK and c[RGDFK], attached to the surface of the prostheses through the 4,7,10-triox-1,13-tridecane diamine linker, showed the best results in terms of endothelial adhesion and maintenance of the viability of the endothelial cells in vitro and endothelialization in vivo; these grafts had high patency after implantation into the bloodstream of small laboratory animals and a less tendency to calcification.

The Effect of Antithrombin III-Independent Thrombin Inhibitors and Heparin on Fibrin Accretion onto Fibrin-Coated Polyethylene

1993 ◽  
Vol 69 (02) ◽  
pp. 130-134 ◽  
Author(s):  
F D Rubens ◽  
J I Weitz ◽  
J L Brash ◽  
R L Kinlough-Rathbone
Keyword(s):  
Vascular Graft ◽  
Antithrombin Iii ◽  
Vascular Grafts ◽  
Barium Chloride ◽  
Thrombin Inhibitors ◽  
Thrombin Inhibitor ◽  
Recombinant Hirudin ◽  
Graft Thrombosis ◽  
Polyethylene Tubing

SummaryProsthetic vascular grafts become coated with a layer of fibrin that contributes to graft thrombosis and occlusion. We compared the effect of antithrombin III-independent inhibitors of thrombin with heparin for their ability to prevent fibrin accretion onto a model of a vascular graft formed in vitro by coating polyethylene tubing with thrombin bound to a layer of polymerized fibrin. Equivalent antithrombin concentrations of heparin, D-Phe-Pro-Arg CH2Cl (PPACK), recombinant hirudin (r-hirudin), and Hirulog-1 were added to barium chloride-adsorbed plasma containing radiolabelled fibrinogen. Whereas, PPACK and r-hirudin persistently inhibited fibrin accretion, the inhibition by heparin was transient. Hirulog-1 had no effect on early fibrin accretion and was actually associated with enhanced accretion at 30 min (control 11.7 ± 2.0 μg fibrin/cm2; Hirulog-1, 18.4 ± 3.5 μg fibrin/cm2, p <0.001). Both Hirulog-1 and r-hirudin displaced radiolabelled thrombin from the fibrin surface. Whereas hirudin-thrombin complexes are stable, Hirulog-1 produces only transient inhibition of the displaced thrombin thereby accounting for the enhanced fibrin accretion with this anticoagulant. These studies show that the antithrombin III-independent inhibitors, r-hirudin and PPACK, are more effective inhibitors of fibrin accretion onto fibrin-coated polyethylene than heparin or Hirulog-1. In addition, they emphasize the importance of determining the ability of anticoagulants to displace thrombin from fibrin and to form stable thrombin-inhibitor complexes; lack of stability of thrombin-inhibitor complexes must be countered by levels of anticoagulant that are adequate to maintain its effectiveness.

Insight on the endothelialization of small silk-based tissue-engineered vascular grafts

2020 ◽  
Vol 43 (10) ◽  
pp. 631-644 ◽  
Author(s):  
Justine Cordelle ◽  
Sara Mantero
Keyword(s):  
Cell Adhesion ◽  
Vascular Tissue ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Graft Patency ◽  
Ongoing Research ◽  
The Right ◽  
And Behavior

Along with an increased incidence of cardiovascular diseases, there is a strong need for small-diameter vascular grafts. Silk has been investigated as a biomaterial to develop such grafts thanks to different processing options. Endothelialization was shown to be extremely important to ensure graft patency and there is ongoing research on the development and behavior of endothelial cells on vascular tissue-engineered scaffolds. This article reviews the endothelialization of silk-based scaffolds processed throughout the years as silk non-woven nets, films, gel spun, electrospun, or woven scaffolds. Encouraging results were reported with these scaffolds both in vitro and in vivo when implanted in small- to middle-sized animals. The use of coatings and heparin or sulfur to enhance, respectively, cell adhesion and scaffold hemocompatibility is further presented. Bioreactors also showed their interest to improve cell adhesion and thus promoting in vitro pre-endothelialization of grafts even though they are still not systematically used. Finally, the importance of the animal models used to study the right mechanism of endothelialization is discussed.

scholarly journals Controllable synthesis of biomimetic nano/submicro-fibrous tubes for potential small-diameter vascular grafts

2020 ◽  
Vol 8 (26) ◽  
pp. 5694-5706
Author(s):  
Yizao Wan ◽  
Shanshan Yang ◽  
Mengxia Peng ◽  
Miguel Gama ◽  
Zhiwei Yang ◽  
...  
Keyword(s):  
Cellulose Acetate ◽  
Bacterial Cellulose ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Controllable Synthesis ◽  
Small Diameter Vascular Grafts

A novel small-diameter graft consisting of nanofibrous bacterial cellulose and submicrofibrous cellulose acetate was prepared and evaluated in vitro and in vivo.

scholarly journals Blood Vessel-Derived Acellular Matrix for Vascular Graft Application

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Luigi Dall’Olmo ◽  
Ilenia Zanusso ◽  
Rosa Di Liddo ◽  
Tatiana Chioato ◽  
Thomas Bertalot ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Immunomagnetic Separation ◽  
Enzymatic Digestion ◽  
Enzymatic Treatment ◽  
Acellular Matrix ◽  
Cell Coverage ◽  
Class Ii Antigens

To overcome the issues connected to the use of autologous vascular grafts and artificial materials for reconstruction of small diameter (<6 mm) blood vessels, this study aimed to develop acellular matrix- (AM-) based vascular grafts. Rat iliac arteries were decellularized by a detergent-enzymatic treatment, whereas endothelial cells (ECs) were obtained through enzymatic digestion of rat skin followed by immunomagnetic separation of CD31-positive cells. Sixteen female Lewis rats (8 weeks old) received only AM or previouslyin vitroreendothelialized AM as abdominal aorta interposition grafts (about 1 cm). The detergent-enzymatic treatment completely removed the cellular part of vessels and both MHC class I and class II antigens. One month after surgery, the luminal surface of implanted AMs was partially covered by ECs and several platelets adhered in the areas lacking cell coverage. Intimal hyperplasia, already detected after 1 month, increased at 3 months. On the contrary, all grafts composed by AM and ECs were completely covered at 1 month and their structure was similar to that of native vessels at 3 months. Taken together, our findings show that prostheses composed of AM preseeded with ECs could be a promising approach for the replacement of blood vessels.

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