scholarly journals Acellular Small-Diameter Tissue-Engineered Vascular Grafts

2019 ◽  
Vol 9 (14) ◽  
pp. 2864 ◽  
Author(s):  
Zhen Li ◽  
Xinda Li ◽  
Tao Xu ◽  
Lei Zhang
Keyword(s):  
Effective Means ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Test Results ◽  
In Vivo Test ◽  
Current State

Tissue-engineered vascular grafts (TEVGs) are considered one of the most effective means of fabricating vascular grafts. However, for small-diameter TEVGs, there are ongoing issues regarding long-term patency and limitations related to long-term in vitro culture and immune reactions. The use of acellular TEVG is a more convincing method, which can achieve in situ blood vessel regeneration and better meet clinical needs. This review focuses on the current state of acellular TEVGs based on scaffolds and gives a summary of the methodologies and in vitro/in vivo test results related to acellular TEVGs obtained in recent years. Various strategies for improving the properties of acellular TEVGs are also discussed.

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 Biocompatibility and Toxicity of Magnetic Nanoparticles in Regenerative Medicine

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
H. Markides ◽  
M. Rotherham ◽  
A. J. El Haj
Keyword(s):  
Magnetic Nanoparticles ◽  
Regenerative Medicine ◽  
Effective Means ◽  
Basic Research ◽  
Normal Function ◽  
Iron Oxide Core ◽  
Therapeutic Doses

Regenerative medicine is a pioneering field aimed at restoring and regenerating the function of damaged cells, organs and tissues in order to establish normal function. It demands the cross communication of disciplines to develop effective therapeutic stem cell based therapies. Nanotechnology has been instrumental in the development and translation of basic research to the clinically relevant therapies. In particular, magnetic nanoparticles (MNPs) have been applied to tag, track and activate stem cells offering an effective means of monitoringin vitroandin vivobehaviour. MNPs are comprised of an iron oxide core with a biocompatible biological polymer. Safety is an issue of constant concern and emphasises on the importance of investigating the issue of toxicity. Any indication of toxicity can ultimately limit the therapeutic efficiency of the therapy. Toxicity is highly dependent on the physical, chemical and structural properties of the MNP itself as well as dose and intended use. Fewin vitrostudies have reported adverse effects of MNP on cells atin vitroin therapeutic doses. However, long termin vivostudies have not been studied as extensively. This review aims to summarise current research in this topic highlighting commonly used toxicity assays to investigate this.

The Primary Investigation on Biological Effect of Mesoporous Bioactive Glass In Vivo

2013 ◽  
Vol 750-752 ◽  
pp. 1651-1655
Author(s):  
Bai Yan Sui ◽  
Cheng Tie Wu ◽  
Jiao Sun
Keyword(s):  
Bioactive Glass ◽  
Biological Effect ◽  
Degradation Products ◽  
Long Term Effect ◽  
Liver And Kidney ◽  
Mesoporous Bioactive Glass

Mesoporous bioactive glass (MBG) has superior bioactivity and degradation than non-mesoporous bioactive glass (BG) in vitro. But the biological effect of MBG in vivo is still unknown. In this study, MBG powders with 20μm were implanted into the femoral condyles in SD rats. BG powders with 20μm were used as a control. The local degradation and osteogenesis were observed at 1 week and 4 weeks after implantation, and the systemic toxicity of the degradation products were also evaluated simultaneously. The results revealed MBG powders had the faster rate of degradation and better osteogenesis effect than BG powders at 4 weeks, although the most of material still remained in situ. Histopathological analyses indicated the degradation products did not have any damage to major organs such as liver and kidney. In conclusion, this preliminary study demonstrated that MBG powders have more excellent biological effect at 4 weeks than that of BG in vivo. However the long-term effect needs to be confirmed.

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.

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 In Vivo Performance of Decellularized Vascular Grafts: A Review Article

2018 ◽  
Vol 19 (7) ◽  
pp. 2101 ◽  
Author(s):  
Chih-Hsun Lin ◽  
Kai Hsia ◽  
Hsu Ma ◽  
Hsinyu Lee ◽  
Jen-Her Lu
Keyword(s):  
Vascular Grafts ◽  
Small Diameter ◽  
Vascular Wall ◽  
Current Status ◽  
Preclinical Studies ◽  
Engineering Research ◽  
Cellular Inflammation ◽  
Surface Modified

Due to poor vessel quality in patients with cardiovascular diseases, there has been an increased demand for small-diameter tissue-engineered blood vessels that can be used as replacement grafts in bypass surgery. Decellularization techniques to minimize cellular inflammation have been applied in tissue engineering research for the development of small-diameter vascular grafts. The biocompatibility of allogenic or xenogenic decellularized matrices has been evaluated in vitro and in vivo. Both short-term and long-term preclinical studies are crucial for evaluation of the in vivo performance of decellularized vascular grafts. This review offers insight into the various preclinical studies that have been performed using decellularized vascular grafts. Different strategies, such as surface-modified, recellularized, or hybrid vascular grafts, used to improve neoendothelialization and vascular wall remodeling, are also highlighted. This review provides information on the current status and the future development of decellularized vascular grafts.

scholarly journals Design and Characterization of a Fluidic Device for the Evaluation of SIS-Based Vascular Grafts

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1198
Author(s):  
Alejandra Riveros ◽  
Monica Cuellar ◽  
Paolo F. Sánchez ◽  
Carolina Muñoz-Camargo ◽  
Juan C. Cruz ◽  
...  
Keyword(s):  
Flow Regime ◽  
In Silico ◽  
Umbilical Vein ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Clinical Implementation ◽  
Cfd Validation ◽  
Pulsatile Pressure

Currently available small diameter vascular conduits present several long-term limitations, which has prevented their full clinical implementation. Commercially available vascular grafts show no regenerative capabilities and eventually require surgical replacement; therefore, it is of great interest to develop alternative regenerative vascular grafts (RVG). Decellularized Small Intestinal Submucosa (SIS) is an attractive material for RVG, however, the evaluation of the performance of these grafts is challenging due to the absence of devices that mimic the conditions found in vivo. Thereby, the objective of this study is to design, manufacture and validate in silico and in vitro, a novel fluidic system for the evaluation of human umbilical vein endothelial cells (HUVECs) proliferation on SIS-based RVG under dynamical conditions. Our perfusion and rotational fluidic system was designed in Autodesk Inventor 2018. In silico Computational Fluid Dynamics (CFD) validation of the system was carried out using Ansys Fluent software from ANSYS, Inc for dynamical conditions of a pulsatile pressure function measured experimentally over a rigid wall model. Mechanical and biological parameters such as flow regime, pressure gradient, wall shear stress (WSS), sterility and indirect cell viability (MTT assay) were also evaluated. Cell adhesion was confirmed by SEM imaging. The fluid flow regime within the system remains laminar. The system maintained sterility and showed low cytotoxicity levels. HUVECs were successfully cultured on SIS-based RVG under both perfusion and rotation conditions. In silico analysis agreed well with our experimental and theoretical results, and with recent in vitro and in vivo reports for WSS. The system presented is a tool for evaluating RVG and represents an alternative to develop new methods and protocols for a more comprehensive study of regenerative cardiovascular devices.

scholarly journals BIODEGRADABLE VASCULAR GRAFT REINFORCED WITH A BIODEGRADABLE SHEATH

2019 ◽  
Vol 8 (2) ◽  
pp. 87-97
Author(s):  
L. V. Antonova ◽  
E. O. Krivkina ◽  
M. A. Rezvova ◽  
V. V. Sevost'yanova ◽  
A. V. Mironov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Growth Factor ◽  
Carotid Artery ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Fold Increase ◽  
Layer By Layer ◽  
Layer Coating

Background. Tissue-engineered vascular grafts can be reinforced by a biostable or biodegradable polymer sheath. A combination of electrospinning, routinely used for fabrication of biodegradable tubular grafts, and the layer-by-layer coating allows forming a polymeric sheath ensuring long-term integrity and high biocompatibility of the vascular grafts after the implantation. Aim To evaluate mechanical properties and in vivo performance of biodegradable small-diameter vascular grafts with a reinforcing sheath.Methods. Tubular grafts (4 mm diameter) were fabricated from poly(3-hydroxybutyrate-co3-hydroxyvalerate) and poly(ε-caprolactone) by emulsion electrospinning with the incorporation of vascular endothelial growth factor (VEGF) into the inner third of the graft and basic fibroblast growth factor (bFGF) along with stromal cell-derived factor-1α (SDF-1α) into the outer two thirds of the graft wall. Poly(ε-caprolactone) sheath was formed by the layer-by-layer coating. Upon graft fabrication, scanning electron microscopy was performed to assess the grafts’ surface, tensile testing allowed evaluating mechanical properties. The samples were implanted into the ovine carotid artery (n = 5 animals) for 12 months with the subsequent histological examination.Results. Sintering temperature of 160°C during the extrusion allowed effective and delicate merging of poly(ε-caprolactone) coating with the outer surface of the poly(3hydroxybutyrate-co-3-hydroxyvalerate)/poly(ε-caprolactone) tubular graft. The thickness of poly(ε-caprolactone) fiber was 380–400 μm, the increment of the reinforcing filament was 1 mm. The reinforcing sheath led to a 3-fold increase in durability and elastic modulus of the vascular grafts. At the 12-months follow-up, the grafts reported retained integrity. No signs of inflammation or calcification were found.Conclusion. The poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and poly(ε-caprolactone) vascular grafts with hierarchically incorporated growth factors and the reinforced poly(ε-caprolactone) spiral sheath demonstrated improved mechanical properties while retaining integrity and high biocompatibility after the long-term implantation into the ovine carotid artery.

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