Mechanical Stimulation of Tissue Engineered Tendon Constructs: Effect of Scaffold Materials

2007 ◽  
Vol 129 (6) ◽  
pp. 919-923 ◽  
Author(s):  
Victor S. Nirmalanandhan ◽  
Matthew R. Dressler ◽  
Jason T. Shearn ◽  
Natalia Juncosa-Melvin ◽  
Marepalli Rao ◽  
...  
Keyword(s):  
Mechanical Stimulation ◽  
Type I Collagen ◽  
Collagen Gel ◽  
Mechanical Stimulus ◽  
Collagen Sponge ◽  
The Other ◽  
Type I ◽  
Peak Strain ◽  
Bovine Collagen

Our group has shown that numerous factors can influence how tissue engineered tendon constructs respond to in vitro mechanical stimulation. Although one study showed that stimulating mesenchymal stem cell (MSC)–collagen sponge constructs significantly increased construct linear stiffness and repair biomechanics, a second study showed no such effect when a collagen gel replaced the sponge. While these results suggest that scaffold material impacts the response of MSCs to mechanical stimulation, a well-designed intra-animal study was needed to directly compare the effects of type-I collagen gel versus type-I collagen sponge in regulating MSC response to a mechanical stimulus. Eight constructs from each cell line (n=8 cell lines) were created in specially designed silicone dishes. Four constructs were created by seeding MSCs on a type-I bovine collagen sponge, and the other four were formed by seeding MSCs in a purified bovine collagen gel. In each dish, two cell-sponge and two cell-gel constructs from each line were then mechanically stimulated once every 5min to a peak strain of 2.4%, for 8h∕day for 2 weeks. The other dish remained in an incubator without stimulation for 2 weeks. After 14 days, all constructs were failed to determine mechanical properties. Mechanical stimulation significantly improved the linear stiffness (0.048±0.009 versus 0.015±0.004; mean±SEM (standard error of the mean ) N/mm) and linear modulus (0.016±0.004 versus 0.005±0.001; mean±SEM MPa) of cell-sponge constructs. However, the same stimulus produced no such improvement in cell-gel construct properties. These results confirm that collagen sponge rather than collagen gel facilitates how cells respond to a mechanical stimulus and may be the scaffold of choice in mechanical stimulation studies to produce functional tissue engineered structures.

scholarly journals EFFECT OF COLLAGEN I GEL ON APOPTOSIS OF RAT HEPATIC STELLATE CELLS

2013 ◽  
Vol 56 (2) ◽  
pp. 73-79
Author(s):  
Lenka Bittnerová ◽  
Alena Jiroutová ◽  
Emil Rudolf ◽  
Martina Řezáčová ◽  
Jiří Kanta
Keyword(s):  
Hepatic Stellate Cells ◽  
Type I Collagen ◽  
Collagen Gel ◽  
Stellate Cells ◽  
Type I ◽  
Function Type ◽  
Fibrotic Liver ◽  
Normal Rat ◽  
And Function

Activated hepatic stellate cells (HSC) are a major source of fibrous proteins in cirrhotic liver. Inducing or accelerating their apoptosis is a potential way of liver fibrosis treatment. Extracellular matrix (ECM) surrounding cells in tissue affects their differentiation, migration, proliferation and function. Type I collagen is the main ECM component in fibrotic liver. We have examined how this protein modifies apoptosis of normal rat HSC induced by gliotoxin, cycloheximide and cytochalasin D in vitro and spontaneous apoptosis of HSC isolated from CCl4-damaged liver. We have found that type I collagen gel enhances HSC apoptosis regardless of the agent triggering this process.

A Continuous-Discrete Finite Element Model of Angiogenesis That Couples Vessel Growth With Matrix Deformation

2013 ◽  
Author(s):  
Lowell T. Edgar ◽  
Steve A. Maas ◽  
James E. Guilkey ◽  
Jeffrey A. Weiss
Keyword(s):  
Type I Collagen ◽  
Three Dimensional ◽  
Collagen Gel ◽  
Element Model ◽  
Fibrillar Structure ◽  
Type I ◽  
Major Pathway ◽  
Vessel Growth ◽  
Discrete Finite Element

Recent developments in tissue engineering have created demand for the ability to create microvascular networks with specific topologies in vitro. During angiogenesis, sprouting endothelial cells apply traction forces and migrate along components of the extracellular matrix (ECM), resulting in neovessel elongation [1]. The fibrillar structure of the ECM serves as the major pathway for mechanotransduction between contact-dependent cells. Using a three-dimensional (3D) organ culture model of microvessel fragments within a type-I collagen gel, we have shown that subjecting the culture to different boundary conditions during angiogenesis can lead to drastically different vascular topologies [2]. Fragments cultured in a rectangular gel that were free to contract grew into a randomly oriented network [3, 4]. When the long-axis of the gel was constrained as to prevent contraction, microvessels and collagen fibers were found aligned along the constrained axis (Fig. 1) [4].

Relationships between mesangial cell proliferation and types I and IV collagen mRNA levels in vitro

1995 ◽  
Vol 269 (3) ◽  
pp. C554-C562 ◽  
Author(s):  
C. J. He ◽  
L. J. Striker ◽  
M. Tsokos ◽  
C. W. Yang ◽  
E. P. Peten ◽  
...  
Keyword(s):  
Type I Collagen ◽  
Mesangial Cell ◽  
Mesangial Cells ◽  
Methyl Cellulose ◽  
Collagen Gel ◽  
Type I ◽  
Mrna Levels ◽  
Collagen Mrna ◽  
Type Iv

Changes in the composition of the mesangial extracellular matrix (ECM) and cell turnover are present in glomerular disease. To determine if ECM changes play a role in perpetuating mesangial cell dysfunction, we examined a line of mouse mesangial cells cultured on films or gels of several ECM components and also on methyl cellulose, an inert substrate that prevents attachment. Cells on films of fibronectin or type IV or I collagen had persistently high growth rates and high levels of alpha 1-I and alpha 1-IV collagen mRNAs. In contrast, on gels of type IV or I collagen or matrigel, the growth rate was low. The alpha 1-IV collagen mRNA levels were low on type IV collagen gel or matrigel, whereas the alpha 1-I collagen mRNA levels remained high. In contrast, the alpha 1-I collagen mRNA levels were low on type I collagen gel, and the alpha 1-IV collagen mRNA levels were high. Cells on methyl cellulose formed floating aggregates, did not proliferate, and had a 5- to 10-fold decrease in both alpha 1-I and alpha 1-IV collagen mRNA levels. These phenotypic changes were largely reversible. Finally, when matrigel was layered over cells on fibronectin films, alpha 1-IV collagen mRNA levels decreased, but alpha 1-I collagen mRNA levels and proliferation remained high. Thus proliferation and alpha 1-I and alpha 1-IV collagen mRNA levels in mesangial cells were independently regulated and depended on attachment and the nature of the adjacent matrix.

Mechanical Stimulation of Tendon Tissue Engineered Constructs: Effects on Construct Stiffness, Repair Biomechanics, and Their Correlation

2007 ◽  
Vol 129 (6) ◽  
pp. 848-854 ◽  
Author(s):  
Jason T. Shearn ◽  
Natalia Juncosa-Melvin ◽  
Gregory P. Boivin ◽  
Marc T. Galloway ◽  
Wendy Goodwin ◽  
...  
Keyword(s):  
Mechanical Stimulation ◽  
Maximum Stress ◽  
Tendon Repair ◽  
The Other ◽  
Maximum Force ◽  
In Vivo Studies ◽  
Peak Strain ◽  
Stimulation Of

The objective of this study was to determine how in vitro mechanical stimulation of tissue engineered constructs affects their stiffness and modulus in culture and tendon repair biomechanics 12weeks after surgical implantation. Using six female adult New Zealand White rabbits, autogenous tissue engineered constructs were created by seeding mesenchymal stem cells (0.1×106cells∕ml) in collagen gel (2.6mg∕ml) and combining both with a collagen sponge. Employing a novel experimental design strategy, four constructs from each animal were mechanically stimulated (one 1Hzcycle every 5min to 2.4% peak strain for 8h∕day for 2weeks) while the other four remained unstretched during the 2week culture period. At the end of incubation, three of the mechanically stimulated (S) and three of the nonstimulated (NS) constructs from each animal were assigned for in vitro mechanical testing while the other two autogenous constructs were implanted into bilateral full-thickness, full-length defects created in the central third of rabbit patellar tendons (PTs). No significant differences were found in the in vitro linear stiffnesses between the S (0.15±0.1N∕mm) and NS constructs (0.08±0.02N∕mm; mean±SD). However, in vitro mechanical stimulation significantly increased the structural and material properties of the repair tissue, including a 14% increase in maximum force (p=0.01), a 50% increase in linear stiffness (p=0.001), and 23–41% increases in maximum stress and modulus (p=0.01). The S repairs achieved 65%, 80%, 60%, and 40% of normal central PT maximum force, linear stiffness, maximum stress, and linear modulus, respectively. The results for the S constructs exceed values obtained previously by our group using the same animal and defect model, and to our knowledge, this is the first study to show the benefits of in vitro mechanical stimulation on tendon repair biomechanics. In addition, the linear stiffnesses for the construct and repair were positively correlated (r=0.56) as were their linear moduli (r=0.68). Such in vitro predictors of in vivo outcome hold the potential to speed the development of tissue engineered products by reducing the time and costs of in vivo studies.

scholarly journals Biological Safety of Fish (Tilapia) Collagen

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Kohei Yamamoto ◽  
Kazunari Igawa ◽  
Kouji Sugimoto ◽  
Yuu Yoshizawa ◽  
Kajiro Yanagiguchi ◽  
...  
Keyword(s):  
Type I Collagen ◽  
Collagen Gel ◽  
Growth Potential ◽  
Type I ◽  
Environmental Signals ◽  
Negative Results ◽  
Biological Studies ◽  
Fish Collagen

Marine collagen derived from fish scales, skin, and bone has been widely investigated for application as a scaffold and carrier due to its bioactive properties, including excellent biocompatibility, low antigenicity, and high biodegradability and cell growth potential. Fish type I collagen is an effective material as a biodegradable scaffold or spacer replicating the natural extracellular matrix, which serves to spatially organize cells, providing them with environmental signals and directing site-specific cellular regulation. This study was conducted to confirm the safety of fish (tilapia) atelocollagen for use in clinical application. We performedin vitroandin vivobiological studies of medical materials to investigate the safety of fish collagen. The extract of fish collagen gel was examined to clarify its sterility. All present sterility tests concerning bacteria and viruses (including endotoxin) yielded negative results, and all evaluations of cell toxicity, sensitization, chromosomal aberrations, intracutaneous reactions, acute systemic toxicity, pyrogenic reactions, and hemolysis were negative according to the criteria of the ISO and the http://dx.doi.org/10.13039/501100003478 Ministry of Health, Labour and Welfare. The present study demonstrated that atelocollagen prepared from tilapia is a promising biomaterial for use as a scaffold in regenerative medicine.

Microvessel formation from mouse embryonic aortic explants is oxygen and VEGF dependent

2002 ◽  
Vol 283 (2) ◽  
pp. R487-R495 ◽  
Author(s):  
Tetsu Akimoto ◽  
Helen Liapis ◽  
Marc R. Hammerman
Keyword(s):  
Type I Collagen ◽  
Three Dimensional ◽  
Collagen Gel ◽  
Type I ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Thoracic Level ◽  
Aortic Explants ◽  
Endothelial Growth Factor

To delineate the roles of O2 and vascular endothelial growth factor (VEGF) in the process of angiogenesis from the embryonic aorta, we cultured mouse embryonic aorta explants (thoracic level to lateral vessels supplying the mesonephros and metanephros) in a three-dimensional type I collagen gel matrix. During 8 days of culture under 5% O2, but not room air, the addition of VEGF to explants stimulated the formation of CD31-positive, Flk-1-positive, Gs-IB4-positive structures in a concentration-dependent manner. Electron microscopy showed the structures to be capillary-like. VEGF-induced capillary-like structure formation was inhibited by sequestration of VEGF via addition of soluble Flt-1 fusion protein or anti-VEGF antibodies. Expression of Flk-1, but not Flt-1, was increased in embryonic aorta cultured under 5% O2 relative to room air. Our data suggest that low O2 upregulates Flk-1 expression in embryonic aorta in vitro and renders it more responsive to VEGF.

In Vitro Reconstruction of Hybrid Arterial Media with Molecular and Cellular Orientations

1994 ◽  
Vol 3 (6) ◽  
pp. 537-545 ◽  
Author(s):  
Keiichi Kanda ◽  
Takehisa Matsuda
Keyword(s):  
Collagen Fiber ◽  
Type I Collagen ◽  
Dynamic Stress ◽  
Collagen Gel ◽  
Fiber Bundles ◽  
Outer Diameter ◽  
Type I ◽  
Silicone Tube ◽  
Aortic Media

A hybrid medial tissue composed of a type I collagen gel, into which smooth muscle cells (SMCs) derived from bovine aortic media were 3-dimensionally (3D) embedded, was constructed around an elastomeric silicone tube (outer diameter: 8 mm). Subsequently, hybrid tissues thus prepared were subjected to three modes of mechanical stimulation in the medium: one was subjected to flotation with no disturbance (isotonic control), the second was kept isometrically (static stress) and the third was subjected to continuous periodic stretch by inflation of the embedded silicone tube which simulated arterial pulsation (dynamic stress, amplitude: 5% in inner diameter; frequency: 60 RPM). After a 5-day culture period, hybrid tissues were morphologically investigated. In control gels, polygonal SMCs and extracellular collagen fiber bundles were randomly oriented. On the other hand, upon static or dynamic stress loading, bipolar spindle-shaped SMCs and dense collagen fiber bundles were aligned circumferentially around the silicone tube, which proceeded with time. The orientations of SMCs and collagen fibers were more prominent in dynamically stressed hybrid tissues than those in statically stressed ones. The pulsatile stress-loaded hybrid medial tissue mimicked the media of native muscular arteries in terms of cellular and molecular orientations.

scholarly journals Efficacy of collagen and alginate hydrogels for the prevention of rat chondrocyte dedifferentiation

2018 ◽  
Vol 9 ◽  
pp. 204173141880243 ◽  
Author(s):  
Guang-Zhen Jin ◽  
Hae-Won Kim
Keyword(s):  
Tissue Engineering ◽  
Type I Collagen ◽  
Cartilage Tissue Engineering ◽  
Collagen Gel ◽  
Type Ii Collagen ◽  
Cartilage Tissue ◽  
Type I ◽  
Type Ii ◽  
Chondrogenic Phenotype

Dedifferentiation of chondrocytes remains a major problem in cartilage tissue engineering. The development of hydrogels that can preserve chondrogenic phenotype and prevent chondrocyte dedifferentiation is a meaningful strategy to solve dedifferentiation problem of chondrocytes. In the present study, three gels were prepared (alginate gel (Alg gel), type I collagen gel (Col gel), and their combination gel (Alg/Col gel)), and the in vitro efficacy of chondrocytes culture while preserving their phenotypes was investigated. While Col gel became substantially contracted with time, the cells encapsulated in Alg gel preserved the shape over the culture period of 14 days. The mechanical and cell-associated contraction behaviors of Alg/Col gel were similar to those of Alg. The cells in Alg and Alg/Col gels exhibited round morphology, whereas those in Col gel became elongated (i.e. fibroblast-like) during cultures. The cells proliferated with time in all gels with the highest proliferation being attained in Col gel. The expression of chondrogenic genes, including SOX9, type II collagen, and aggrecan, was significantly up-regulated in Alg/Col gel and Col gel, particularly in Col gel. However, the chondrocyte dedifferentiation markers, type I collagen and alkaline phosphatase ( ALP), were also expressed at significant levels in Col gel, which being contrasted with the events in Alg and Alg/Col gels. The current results suggest the cells cultured in hydrogels can express chondrocyte dedifferentiation markers as well as chondrocyte markers, which draws attention to choose proper hydrogels for chondrocyte-based cartilage tissue engineering.

Fibroblast growth factor 2 promotes microvessel formation from mouse embryonic aorta

2003 ◽  
Vol 284 (2) ◽  
pp. C371-C377 ◽  
Author(s):  
Tetsu Akimoto ◽  
Marc R. Hammerman
Keyword(s):  
Type I Collagen ◽  
Three Dimensional ◽  
Collagen Gel ◽  
Type I ◽  
Dependent Manner ◽  
Fibroblast Growth ◽  
Low Oxygen ◽  
Concentration Dependent Manner ◽  
Fgf Receptor

To delineate the roles that oxygen and fibroblast growth factors (FGFs) play in the process of angiogenesis from the embryonic aorta, we cultured mouse embryonic aorta explants (thoracic level to lateral vessels supplying the mesonephros and metanephros) in a three-dimensional type I collagen gel matrix. During 8 days of culture under 5% O2, but not room air, the addition of FGF2 to explants stimulated the formation of Gs-IB4-positive, CD31-positive, and Flk-1-positive microvessels in a concentration-dependent manner. FGF2-stimulated microvessel formation was inhibited by sequestration of FGF2 via addition of soluble FGF receptor (FGFR) chimera protein or anti-FGF2 antibodies. FGFR1 and FGFR2 were present on explants. Levels of FGFR1, but not FGFR2, were increased in embryonic aorta cultured under 5% O2 relative to room air. Our data suggest that low oxygen upregulates FGFR1 expression in embryonic aorta in vitro and renders it more responsive to FGF2.

scholarly journals Three-Dimensional Seeding of Chondrocytes Encapsulated in Collagen Gel into PLLA Scaffolds

2002 ◽  
Vol 11 (5) ◽  
pp. 489-494 ◽  
Author(s):  
Takashi Ushida ◽  
Katsuko Furukawa ◽  
Kenshi Toita ◽  
Tetsuya Tateishi
Keyword(s):  
Tissue Engineering ◽  
Type I Collagen ◽  
Collagen Gel ◽  
Type I ◽  
Cell Seeding ◽  
3D Scaffold ◽  
3D Scaffolds ◽  
Plla Scaffold ◽  
Collagen Solution

Tissue engineering approaches have been clinically tried to repair damaged articular cartilages. It is an essential step to uniformly seed chondrocytes into 3D scaffolds in order to reconstruct tissue-engineered cartilages in vitro, but the tissue engineering could not have been provided with efficient cell seeding methods. Type I collagen is clinically used and known as a cytocompatible material, having recognition sites for integrins. Collagen gel encapsulating chondrocytes has been tried for making regenerated cartilages, but it is found difficult to have the gel keep its original shape after long-term culture, because of shrinking. On the other hand, 3D scaffolds, either of a nonwoven structure or a sponge-like structure, involve difficulty in that chondrocytes could not be uniformly seeded, although they have adequate initial mechanical properties. In this study, by combining collagen gelation with a nonwoven PLLA scaffold, we achieved uniform cell seeding into the 3D scaffold. Bovine articular chondrocytes were mixed with type I collagen solution, and the solution was poured into the nonwoven PLLA scaffold (1.5 mm thick, f 15 mm). The collagen–chondrocyte mixture was made into gel at 37°C for 1 h. The 0.39% collagen mixture was viscous enough to prevent cells from precipitating during gelation. Almost all chondrocytes were able to be incorporated into the PLLA scaffolds by mixing with collagen solution and subsequently making into gel, while 30–40% of the chondrocytes seeded as a cell suspension were not trapped into the PLLA scaffolds. The method presented, where chondrocytes were mixed with collagen solution, and the mixture was incorporated into a 3D scaffold, then made into gel in the scaffold, could serve as an alternative for in vitro cartilage regeneration, also simultaneously having the advantages of both materials.

Sign in / Sign up

Export Citation Format

Share Document