scholarly journals Glycosaminoglycans: From Vascular Physiology to Tissue Engineering Applications

2021 ◽  
Vol 9 ◽  
Author(s):  
Antonio Junior Lepedda ◽  
Gabriele Nieddu ◽  
Marilena Formato ◽  
Matthew Brandon Baker ◽  
Julia Fernández-Pérez ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Growth Factors ◽  
Tissue Regeneration ◽  
Vascular Tissue ◽  
Small Diameter ◽  
Relative Molecular Mass ◽  
Vascular Cells ◽  
Vascular Events ◽  
Vascular Regeneration

Cardiovascular diseases represent the number one cause of death globally, with atherosclerosis a major contributor. Despite the clinical need for functional arterial substitutes, success has been limited to arterial replacements of large-caliber vessels (diameter > 6 mm), leaving the bulk of demand unmet. In this respect, one of the most challenging goals in tissue engineering is to design a “bioactive” resorbable scaffold, analogous to the natural extracellular matrix (ECM), able to guide the process of vascular tissue regeneration. Besides adequate mechanical properties to sustain the hemodynamic flow forces, scaffold’s properties should include biocompatibility, controlled biodegradability with non-toxic products, low inflammatory/thrombotic potential, porosity, and a specific combination of molecular signals allowing vascular cells to attach, proliferate and synthesize their own ECM. Different fabrication methods, such as phase separation, self-assembly and electrospinning are currently used to obtain nanofibrous scaffolds with a well-organized architecture and mechanical properties suitable for vascular tissue regeneration. However, several studies have shown that naked scaffolds, although fabricated with biocompatible polymers, represent a poor substrate to be populated by vascular cells. In this respect, surface functionalization with bioactive natural molecules, such as collagen, elastin, fibrinogen, silk fibroin, alginate, chitosan, dextran, glycosaminoglycans (GAGs), and growth factors has proven to be effective. GAGs are complex anionic unbranched heteropolysaccharides that represent major structural and functional ECM components of connective tissues. GAGs are very heterogeneous in terms of type of repeating disaccharide unit, relative molecular mass, charge density, degree and pattern of sulfation, degree of epimerization and physicochemical properties. These molecules participate in a number of vascular events such as the regulation of vascular permeability, lipid metabolism, hemostasis, and thrombosis, but also interact with vascular cells, growth factors, and cytokines to modulate cell adhesion, migration, and proliferation. The primary goal of this review is to perform a critical analysis of the last twenty-years of literature in which GAGs have been used as molecular cues, able to guide the processes leading to correct endothelialization and neo-artery formation, as well as to provide readers with an overall picture of their potential as functional molecules for small-diameter vascular regeneration.

scholarly journals Mathematical Modeling of Uniaxial Mechanical Properties of Collagen Gel Scaffolds for Vascular Tissue Engineering

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Ramiro M. Irastorza ◽  
Bernard Drouin ◽  
Eugenia Blangino ◽  
Diego Mantovani
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Vascular Tissue ◽  
Nonlinear Models ◽  
Small Diameter ◽  
Collagen Gel ◽  
Vascular Tissue Engineering ◽  
Suitable Model ◽  
Collagen Gels ◽  
Hammerstein Models

Small diameter tissue-engineered arteries improve their mechanical and functional properties when they are mechanically stimulated. Applying a suitable stress and/or strain with or without a cycle to the scaffolds and cells during the culturing process resides in our ability to generate a suitable mechanical model. Collagen gel is one of the most used scaffolds in vascular tissue engineering, mainly because it is the principal constituent of the extracellular matrix for vascular cells in human. The mechanical modeling of such a material is not a trivial task, mainly for its viscoelastic nature. Computational and experimental methods for developing a suitable model for collagen gels are of primary importance for the field. In this research, we focused on mechanical properties of collagen gels under unconfined compression. First, mechanical viscoelastic models are discussed and framed in the control system theory. Second, models are fitted using system identification. Several models are evaluated and two nonlinear models are proposed: Mooney-Rivlin inspired and Hammerstein models. The results suggest that Mooney-Rivlin and Hammerstein models succeed in describing the mechanical behavior of collagen gels for cyclic tests on scaffolds (with best fitting parameters 58.3% and 75.8%, resp.). When Akaike criterion is used, the best is the Mooney-Rivlin inspired model.

scholarly journals Fibrin – a promising material for vascular tissue engineering

2020 ◽  
Vol 22 (1) ◽  
pp. 196-208
Author(s):  
V. G. Matveeva ◽  
M. U. Khanova ◽  
L. V. Antonova ◽  
L. S. Barbarash
Keyword(s):  
Tissue Engineering ◽  
Growth Factors ◽  
Side Effects ◽  
Vascular Tissue ◽  
Cell Attachment ◽  
Three Dimensional ◽  
Small Diameter ◽  
Vascular Tissue Engineering ◽  
High Porosity ◽  
Fibrin Gel

This review looks at the use of fibrin in vascular tissue engineering (VTE). Autologous fibrin is one of the most affordable biopolymers because it can be obtained from peripheral blood by simple techniques. A description and comparative analysis of the methods and approaches for producing fibrin gel is provided. The ability of fibrin to promote cell attachment and migration, survival and angiogenesis, to accumulate growth factors and release them in a controlled manner, are unique and extremely useful in VTE. Fibrin gels can serve as a three-dimensional matrix molded in different sizes and shapes to be applied in a variety of ways, including as a scaffold, coating, or impregnation material. Fibrin’s high porosity and biodegradability allows controllable release of growth factors, yet fibrinolysis must be tightly regulated to avoid side effects. We discuss the main methods of regulating the rate of fibrinolysis, as well as possible side effects of such exposure. Low mechanical strength is the main limitation in using fibrin as a scaffold for vascular tissue engineering. Possible options for increasing the strength properties of fibrin matrix and evaluating their effectiveness are presented. We propose that unique biocompatibility and ideal biodegradation profile of fibrin justify its use as a scaffold material for developing an ideal fully autologous small-diameter tissue-engineered vascular graft.

scholarly journals Sonication-Assisted Method for Decellularization of Human Umbilical Artery for Small-Caliber Vascular Tissue Engineering

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1699
Author(s):  
Chih-Hsun Lin ◽  
Kai Hsia ◽  
Chih-Kuan Su ◽  
Chien-Chin Chen ◽  
Chang-Ching Yeh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Umbilical Artery ◽  
Vascular Tissue ◽  
Treatment Time ◽  
Umbilical Vein ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Ultrasonic Power ◽  
Human Umbilical Artery

Decellularized vascular grafts are useful for the construction of biological small-diameter tissue-engineered vascular grafts (≤6 mm). Traditional chemical decellularization requires a long treatment time, which may damage the structure and alter the mechanical properties. Decellularization using sonication is expected to solve this problem. The aim of this study was to develop an effective decellularization method using ultrasound followed by washing. Different power values of sonication at 40 kHz were tested for 2, 4, and 8 h followed by a washing procedure. The efficacy of sonication of decellularized human umbilical artery (sDHUA) was evaluated via DNA content, histological staining, mechanical properties, and biocompatibility. The sDHUAs were further implanted into rats for up to 90 days and magnetic resonance angiography (MRA) was performed for the implanted grafts. The results demonstrated that treatment of human umbilical artery (HUA) by sonication at ultrasonic power of 204 W for 4 h followed by washing for 24 h in 2% SDS buffer could eliminate more than 90% of cells and retain similar mechanical properties of the HUA. Recellularization was assessed by scanning electron microscopy (SEM), which indicated that sDHUA provided niches for human umbilical vein endothelial cells (HUVECs) to reside, indicating in vitro cytocompatibility. Further implantation tests also indicated the fitness of the sonication-treated HUA as a scaffold for small-caliber tissue engineering vascular grafts.

scholarly journals Effects of a Pseudophysiological Environment on the Elastic and Viscoelastic Properties of Collagen Gels

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Sébastien Meghezi ◽  
Frédéric Couet ◽  
Pascale Chevallier ◽  
Diego Mantovani
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Viscoelastic Properties ◽  
Saline Solution ◽  
Vascular Tissue ◽  
Small Diameter ◽  
Tensile Tests ◽  
Biological Properties ◽  
Vascular Tissue Engineering ◽  
Collagen Gels

Vascular tissue engineering focuses on the replacement of diseased small-diameter blood vessels with a diameter less than 6 mm for which adequate substitutes still do not exist. One approach to vascular tissue engineering is to culture vascular cells on a scaffold in a bioreactor. The bioreactor establishes pseudophysiological conditions for culture (medium culture, 37°C, mechanical stimulation). Collagen gels are widely used as scaffolds for tissue regeneration due to their biological properties; however, they exhibit low mechanical properties. Mechanical characterization of these scaffolds requires establishing the conditions of testing in regard to the conditions set in the bioreactor. The effects of different parameters used during mechanical testing on the collagen gels were evaluated in terms of mechanical and viscoelastic properties. Thus, a factorial experiment was adopted, and three relevant factors were considered: temperature (23°C or 37°C), hydration (aqueous saline solution or air), and mechanical preconditioning (with or without). Statistical analyses showed significant effects of these factors on the mechanical properties which were assessed by tensile tests as well as stress relaxation tests. The last tests provide a more consistent understanding of the gels' viscoelastic properties. Therefore, performing mechanical analyses on hydrogels requires setting an adequate environment in terms of temperature and aqueous saline solution as well as choosing the adequate test.

Influence of different concentrations of fibrinogen on the properties of a fibrin matrix for vascular tissue engineering

2021 ◽  
Vol 29 (1) ◽  
pp. 21-34
Author(s):  
Vera G. Matveeva ◽  
Mariam Yu. Khanova ◽  
Tatyana V. Glushkova ◽  
Larisa V. Antonova
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Metabolic Activity ◽  
Vascular Tissue ◽  
Physical And Mechanical Properties ◽  
Vascular Tissue Engineering ◽  
Test Machine ◽  
Fibrin Matrix ◽  
Before And After ◽  
The Difference

Aim. To evaluate the potential utility of fibrin matrices containing 10, 20, and 25 mg/ml of fibrinogen (fibrin-10, fibrin-20, and fibrin-30, respectively) in vascular tissue engineering (VTE). Materials and Methods. Fibrinogen was isolated using the method of ethanol cryoprecipitation and polymerized using a solution of thrombin and CaCl2. The fibrin structure was studied in a scanning electron microscope, and the physical and mechanical properties of the material were tested on a Zwick/Roell test machine. The metabolic activity of endothelial cells (EC) on the fibrin surface was evaluated by the MTT assay, and the viability of fibroblasts in the thickness of fibrin and possibility for migration by in fluorescent and light microscopy. Percent of fibrin shrinkage was determined from the difference in the sample volumes before and after removal of moisture. Results. The fiber diameter did not differ among all fibrin samples, but the pore diameter in fibrin-30 was smaller than those in fibrin-10 and fibrin-20. A possibility for migration of fibroblasts into the depth of the fibrin matrix and preservation of 97-100% viability of cells at a depth 5 mm was confirmed. The metabolic activity of EC on the surface of fibrin-20 and fibrin-30 exceeded that on collagen, fibronectin, and fibrin-10. All fibrin samples shrank in volume to 95.5-99.5%, and the highest shrinkage was seen in fibrin-10. The physical and mechanical properties of fibrin were inferior to those of human A. mammaria by a factor of 10. Conclusion. Fibrin with fibrinogen concentrations of 20 and 30 mg/ml maintains a high metabolic and proliferative activity of EC on the surface and also a high viability of fibroblasts in the matrix. Its availability, ease of preparation, and a number of other favorable properties make fibrin a promising material for VTE. However, the problem of insufficient strength requires further investigations.

Scaffolds in tissue engineering of blood vessels

2010 ◽  
Vol 88 (9) ◽  
pp. 855-873 ◽  
Author(s):  
Divya Pankajakshan ◽  
Devendra K. Agrawal
Keyword(s):  
Tissue Engineering ◽  
Extracellular Matrix ◽  
Blood Vessels ◽  
Vascular Tissue ◽  
Small Diameter ◽  
Biological Scaffolds ◽  
Hemodynamic Forces ◽  
Biodegradable Scaffolds

Tissue engineering of small diameter (<5 mm) blood vessels is a promising approach for developing viable alternatives to autologous vascular grafts. It involves in vitro seeding of cells onto a scaffold on which the cells attach, proliferate, and differentiate while secreting the components of extracellular matrix that are required for creating the tissue. The scaffold should provide the initial requisite mechanical strength to withstand in vivo hemodynamic forces until vascular smooth muscle cells and fibroblasts reinforce the extracellular matrix of the vessel wall. Hence, the choice of scaffold is crucial for providing guidance cues to the cells to behave in the required manner to produce tissues and organs of the desired shape and size. Several types of scaffolds have been used for the reconstruction of blood vessels. They can be broadly classified as biological scaffolds, decellularized matrices, and polymeric biodegradable scaffolds. This review focuses on the different types of scaffolds that have been designed, developed, and tested for tissue engineering of blood vessels, including use of stem cells in vascular tissue engineering.

scholarly journals Porous Cellulose-Collagen Scaffolds For Soft Tissue Regeneration: Influence of Cellulose Derivatives On Mechanical Properties And Compatibility With Adipose-Derived Stem Cells.

2022 ◽  
Author(s):  
Katarína Kacvinská ◽  
Martina Trávničková ◽  
Lucy Vojtová ◽  
Petr Poláček ◽  
Jana Dorazilová ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Stem Cells ◽  
Cell Adhesion ◽  
Soft Tissue ◽  
Vascular Tissue ◽  
Biological Properties ◽  
Cellulose Derivatives ◽  
Adipose Derived Stem Cells ◽  
Soft Tissue Regeneration

Abstract This study deals with cellulose derivatives in relation to the collagen fibrils in composite collagen-cellulose scaffolds for soft tissue engineering. Two types of cellulose, i.e., oxidized cellulose (OC) and carboxymethyl cellulose (CMC), were blended with collagen (Col) to enhance its elasticity, stability and sorptive biological properties, e.g. hemostatic and antibacterial features. The addition of OC supported the resistivity of the Col fibrils in a dry environment, while in a moist environment OC caused a radical drop. The addition of CMC reduced the mechanical strength of the Col fibrils in both environments. The elongation of the Col fibrils was increased by both types of cellulose derivatives in both environments, which is closely related to tissue like behaviour. In these various mechanical environments, the ability of human adipose-derived stem cells (hADSCs) to adhere and proliferate was significantly greater in the Col and Col/OC scaffolds than in the Col/CMC scaffold. This is explained by deficient mechanical support and loss of stiffness due to the high swelling capacity of CMC. Although Col/OC and Col/CMC acted differently in terms of mechanical properties, both materials were observed to be cytocompatible, with varying degrees of further support for cell adhesion and proliferation. While Col/OC can serve as a scaffolding material for vascular tissue engineering and for skin tissue engineering, Col/CMC seems to be more suitable for moist wound healing, e.g. as a mucoadhesive gel for exudate removal, since there was almost no cell adhesion.

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