scholarly journals Biomechanical, Biochemical, and Cell Biological Evaluation of Different Collagen Scaffolds for Tendon Augmentation

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Carolin Gabler ◽  
Juliane Spohn ◽  
Thomas Tischer ◽  
Rainer Bader
Keyword(s):  
Biomechanical Testing ◽  
Cell Activity ◽  
Collagen Scaffold ◽  
Biomechanical Properties ◽  
Enzymatic Digestion ◽  
Biological Evaluation ◽  
Collagen Scaffolds ◽  
Beneficial Effects ◽  
Bovine Collagen

Tendon augmentation is increasingly clinically relevant due to rising amount of tendon ruptures because of the aging and more demanding population. Therefore, newly developed scaffolds based on bovine epoxide stabilized collagen maintaining the native fibril-like collagen structure were characterized and compared to two commercially available porcine collagen scaffolds. For biomechanical testing (ultimate load, ultimate stress, stiffness, and elastic modulus), bovine collagen scaffolds were hydrated and compared to reference products. Cell viability and proliferation were assessed by seeding human primary fibroblasts on each collagen-based scaffold and cultured over various time periods (3 d, 7 d, and 14 d). Live/dead staining was performed and metabolic cell activity (WST-1 assay) was measured. Biochemical degradability was investigated by enzymatic digestion. The bovine collagen scaffold showed significantly enhanced biomechanical properties. These persisted over different rehydration times. Cell biological tests revealed that the bovine collagen scaffolds support reproducible cell colonization and a significant increase in the number of viable cells during cultivation. The results are comparable with the viability and proliferation rate of cells grown on porcine reference materials. With regard to biochemical degradability, all tested materials showed comparable resistance to enzymatic degradation in vitro. Due to imitating the natural tendon structure the new scaffold material is supposed to provide beneficial effects in future clinical application.

scholarly journals Anisotropic mineralized collagen scaffolds accelerate osteogenic response in a glycosaminoglycan-dependent fashion

2020 ◽  
Author(s):  
Marley J. Dewey ◽  
Andrey V. Nosatov ◽  
Kiran Subedi ◽  
Brendan Harley
Keyword(s):  
Cell Activity ◽  
Collagen Scaffold ◽  
Human Mesenchymal Stem Cell ◽  
Collagen Scaffolds ◽  
Age Related ◽  
Heparin Sulfate ◽  
Osteogenic Response ◽  
Mineralized Collagen

ABSTRACTRegeneration of critically-sized craniofacial bone defects requires a template to promote cell activity and bone remodeling. However, induced regeneration becomes more challenging with increasing defect size. Methods of repair using allografts and autografts have inconsistent results, attributed to age-related regenerative capabilities of bone. We are developing a mineralized collagen scaffold to promote craniomaxillofacial bone regeneration as an alternative to repair. Here, we hypothesize modifying the pore anisotropy and glycosaminoglycan content of the scaffold will improve cell migration, viability, and subsequent bone formation. Using anisotropic and isotropic scaffold variants, we test the role of pore orientation on human mesenchymal stem cell (MSC) activity. We subsequently explore the role of glycosaminoglycan content, notably chondroitin-6-sulfate, chondroitin-4-sulfate, and heparin sulfate on mineralization. We find that while short term MSC migration and activity was not affected by pore orientation, increased bone mineral synthesis was observed in anisotropic scaffolds. Further, while scaffold glycosaminoglycan content did not impact cell viability, heparin sulfate and chondroitin-6-sulfate containing variants increased mineral formation at the late stage of in vitro culture, respectively. Overall, these findings show scaffold microstructural and proteoglycan modifications represent a powerful tool to improve MSC osteogenic activity.

scholarly journals A Collagen-Based Scaffold for Promoting Neural Plasticity in a Rat Model of Spinal Cord Injury

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2245
Author(s):  
Jue-Zong Yeh ◽  
Ding-Han Wang ◽  
Juin-Hong Cherng ◽  
Yi-Wen Wang ◽  
Gang-Yi Fan ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Rat Model ◽  
Neural Plasticity ◽  
Collagen Scaffold ◽  
Glial Scar ◽  
Beneficial Effects ◽  
Cord Injury

In spinal cord injury (SCI) therapy, glial scarring formed by activated astrocytes is a primary problem that needs to be solved to enhance axonal regeneration. In this study, we developed and used a collagen scaffold for glial scar replacement to create an appropriate environment in an SCI rat model and determined whether neural plasticity can be manipulated using this approach. We used four experimental groups, as follows: SCI-collagen scaffold, SCI control, normal spinal cord-collagen scaffold, and normal control. The collagen scaffold showed excellent in vitro and in vivo biocompatibility. Immunofluorescence staining revealed increased expression of neurofilament and fibronectin and reduced expression of glial fibrillary acidic protein and anti-chondroitin sulfate in the collagen scaffold-treated SCI rats at 1 and 4 weeks post-implantation compared with that in untreated SCI control. This indicates that the collagen scaffold implantation promoted neuronal survival and axonal growth within the injured site and prevented glial scar formation by controlling astrocyte production for their normal functioning. Our study highlights the feasibility of using the collagen scaffold in SCI repair. The collagen scaffold was found to exert beneficial effects on neuronal activity and may help in manipulating synaptic plasticity, implying its great potential for clinical application in SCI.

scholarly journals Assessment of In Vitro Bioaccessibility of Polyphenols from Annurca, Limoncella, Red Delicious, and Golden Delicious Apples Using a Sequential Enzymatic Digestion Model

Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 541
Author(s):  
Giulia Graziani ◽  
Anna Gaspari ◽  
Claudio Di Vaio ◽  
Aurora Cirillo ◽  
Carolina Liana Ronca ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Activities ◽  
In Vitro Digestion ◽  
Enzymatic Digestion ◽  
Beneficial Effects ◽  
Golden Delicious ◽  
In Vitro Bioaccessibility ◽  
Inflammatory Processes ◽  
Great Relevance

Four different varieties of apples have been considered (Limoncella, Annurca, Red Delicious, and Golden Delicious) to estimate the extent of colon polyphenolics release after in vitro sequential enzyme digestion. Since several studies report a positive effect of apple polyphenols in colonic damage, we found of interest to investigate the colon release of polyphenols in different varieties of apples in order to assess their prevention of colonic damage. UHPLC-HRMS analysis and antioxidant activity (ABTS, DPPH, and FRAP assays) were carried out on the apple extracts (peel, flesh, and whole fruit) obtained from not digested samples and on bioaccessible fractions (duodenal and colon bioaccessible fractions) after in vitro digestion. Polyphenolic content and antioxidant activities were found to vary significantly among the tested cultivars with Limoncella showing the highest polyphenol content accompanied by an excellent antioxidant activity in both flesh and whole fruit. The overall trend of soluble antioxidant capacity from the soluble duodenal phase (SDP) and soluble colonic phase (SCP) followed the concentrations of flavanols, procyandinis, and hydroxycinnamic acids under the same digestive steps. Our results highlighted that on average 64.2% of the total soluble antioxidant activity was released in the SCP with Limoncella exhibiting the highest values (82.31, 70.05, and 65.5%, respectively for whole fruit, flesh, and peel). This result suggested that enzymatic treatment with pronase E and viscozyme L, to reproduce biochemical conditions occurring in the colon, is effective for breaking the dietary fiber-polyphenols interactions and for the release of polyphenols which can exercise their beneficial effects in the colon. The beneficial effects related to the Limoncella consumption could thus be of potential great relevance to counteract the adverse effects of pro-oxidant and inflammatory processes on intestinal cells.

Kinematic and Kinetic Comparison of Fresh Frozen and Thiel-Embalmed Human Feet for Suitability for Biomechanical Educational and Research Settings

2019 ◽  
Vol 109 (2) ◽  
pp. 113-121 ◽  
Author(s):  
Alfred Gatt ◽  
Pierre Schembri-Wismayer ◽  
Nachiappan Chockalingam ◽  
Cynthia Formosa
Keyword(s):  
Human Subjects ◽  
Biomechanical Testing ◽  
Biomechanical Properties ◽  
Kinetic Properties ◽  
Foot Pressure ◽  
Human Foot ◽  
Observational Study Design ◽  
Fresh Frozen ◽  
Research And Education

Background: In vitro biomechanical testing of the human foot often involves the use of fresh frozen cadaveric specimens to investigate interventions that would be detrimental to human subjects. The Thiel method is an alternative embalming technique that maintains soft-tissue consistency similar to that of living tissue. However, its suitability for biomechanical testing is unknown. Thus, the aim of this study was to determine whether Thiel-embalmed foot specimens exhibit kinematic and kinetic biomechanical properties similar to those of fresh frozen specimens. Methods: An observational study design was conducted at a university biomechanics laboratory. Three cadavers had both limbs amputated, with one being fresh frozen and the other preserved by Thiel's embalming. Each foot was tested while undergoing plantarflexion and dorsiflexion in three states: unloaded and under loads of 10 and 20 kg. Their segment kinematics and foot pressure mapping were assessed simultaneously. Results: No statistically significant differences were detected between fresh frozen and Thiel-embalmed sample pairs regarding kinematics and kinetics. Conclusions: These findings highlight similar kinematic and kinetic properties between fresh frozen and Thiel-embalmed foot specimens, thus possibly enabling these specimens to be interchanged due to the latter specimens' advantage of delayed decomposition. This can open innovative opportunities for the use of these specimens in applications related to the investigation of dynamic foot function in research and education.

scholarly journals Lacidipine Ameliorates the Endothelial Senescence and Inflammatory Injury Through CXCR7/P38/C/EBP-β Signaling Pathway

2021 ◽  
Vol 8 ◽  
Author(s):  
Xing Liu ◽  
Zhuoshan Huang ◽  
Yuanyuan Zhang ◽  
Xing Shui ◽  
Fanmao Liu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Signaling Pathway ◽  
Cell Activity ◽  
Protective Role ◽  
Cell Counting ◽  
Control Group ◽  
Inflammatory Injury ◽  
Beneficial Effects

Background: Lacidipine, a third-generation calcium channel blocker, exerts beneficial effects on the endothelium of hypertensive patients in addition to blood pressure lowering. However, the detailed mechanism underlying Lacidipine-related endothelial protection is still elusive.Methods: Sixteen spontaneous hypertensive rats (SHRs) were randomly divided into two groups: Lacidipine-treated SHR group and saline-treated control group. Tail systolic blood pressure was monitored for four consecutive weeks. Endothelial cells (ECs) were pretreated with Lacidipine prior to being stimulated with H2O2, bleomycin, or Lipopolysaccharides (LPS) in vitro. Then, cell activity, migration, and senescence were measured by Cell Counting Kit-8 assay, transwell assay, and β-galactosidase staining, respectively. The fluorescent probe 2′, 7′-dichlorofluorescein diacetate (DCFH-DA) was used to assess the intracellular reactive oxygen species (ROS). Related protein expression was detected by Western blotting and immunofluorescence.Results: Our data showed that Lacidipine treatment lowered the blood pressure of SHRs accompanied by the elevation of CXCR7 expression and suppression of P38 and CCAAT/enhancer-binding protein beta (C/EBP-β) compared with the control group. In vitro experiments further demonstrated that Lacidipine increased the cell viability and function of ECs under oxidative stress, cell senescence, and inflammatory activation via the CXCR7/P38/signaling pathway.Conclusions: Our results suggested that Lacidipine plays a protective role in EC senescence, oxidative stress, and inflammatory injury through the regulation of CXCR7/P38/C/EBP-β signaling pathway.

Sind winkelstabile Plattensysteme mit elastischen Eigenschaften für die Stabilisierung der Oberarmkopffraktur vorteilhaft? / Eine in-vitro biomechanische Untersuchung

2004 ◽  
Vol 49 (12) ◽  
Author(s):  
M. H Hessmann ◽  
W Sternstein ◽  
D Mehler ◽  
J Korner ◽  
A Hofmann ◽  
...  
Keyword(s):  
Proximal Humerus ◽  
Axial Loading ◽  
Biomechanical Properties ◽  
Torsional Stiffness ◽  
Unstable Fracture ◽  
Beneficial Effects ◽  
Increased Risk ◽  
Cutting Out ◽  
Load To Failure

AbstractWinkelstabile Platten werden mit zunehmender Häufigkeit zur Stabilisierung von Oberarmkopfbrüchen verwendet. Rigide Implantate führen bei osteoporotischen Knochenverhältnissen u. U. aber häufiger zum Versagen. Um den Effekt der Implantatelastizität zu beurteilen wurden in einer in-vitro Studie die biomechanischen Eigenschaften eines rigiden und eines elastischen winkelstabilen Plattensystems vergleichend analysiert. An 8 Humeruspaaren wurde eine instabile subkapitale Fraktur simuliert. Die Proben wurden axial- und torsions-belastet. Analysiert wurden die Steifigkeit, das Setzverhalten unter Dauerlast und die Versagensbelastung.Das elastische Plattensystem kennzeichnete sich durch eine geringere Torsionssteifigkeit und eine größere Verformung unter Axial- und Torsionsbelastung. Die Proben versagten früher als beim rigiden Plattenystem.Unter biomechanischen Gesichtspunkten bieten Implantate mit elastischen Eigenschaften am Oberarmkopf somit keine Vorteile. There is a recent interest for the use of angle-fixed plates in the management of proximal humerus fractures. Rigid implants might be associated with an increased risk of cutting-out. In order to analyse the potential beneficial effects of the implant elasticity on fracture fixation, the biomechanical properties of a rigid and an elastic angle-fixed plating system were assessed in an experimental study. An unstable fracture of the surgical neck was created in 8 pairs of human humeri. Specimens were subjected to axial loading and torque. Stiffness, subsidence and load to failure were assessed.The implant with elastic properties was characterized by a lower torsional stiffness and a higher subsidence during axial loading and torque. This implant failed at lower loads than the rigid implant did.Elastic implant properties of angle-fixed plates have shown not to be advantageous for the management of fractures of the proximal humerus.

Biomechanical Testing of Distal Radius Fracture Treatments: Boundary Conditions Significantly Affect the Outcome of In Vitro Experiments

2016 ◽  
Vol 32 (2) ◽  
pp. 210-214 ◽  
Author(s):  
Alexander Synek ◽  
Yan Chevalier ◽  
Christian Schröder ◽  
Dieter H. Pahr ◽  
Sebastian F. Baumbach
Keyword(s):  
Boundary Conditions ◽  
Distal Radius Fracture ◽  
Distal Radius ◽  
Plate Osteosynthesis ◽  
Biomechanical Testing ◽  
Biomechanical Properties ◽  
Biomechanical Study ◽  
Radius Fracture ◽  
Compression Tests

The variety of experimental setups used during in vitro testing of distal radius fracture treatments impairs interstudy comparison and might lead to contradictory results. Setups particularly differ with respect to their boundary conditions, but the influence on the experimental outcome is unknown. The aim of this biomechanical study was to investigate the effects of 2 common boundary conditions on the biomechanical properties of an extra-articular distal radius fracture treated using volar plate osteosynthesis. Uniaxial compression tests were performed on 10 synthetic radii that were randomized into a proximally constrained group (ProxConst) or proximally movable group (ProxMove). The load was applied distally through a ball joint to enable distal fragment rotation. A significantly larger (ProxConst vs ProxMove) stiffness (671.6 ± 118.9 N·mm−1 vs 259.6 ± 49.4 N·mm−1), elastic limit (186.2 ± 24.4 N vs 75.4 ± 20.2 N), and failure load (504.9 ± 142.5 N vs 200.7 ± 49.0 N) were found for the ProxConst group. The residual tilt did not differ significantly between the 2 groups. We concluded that the boundary conditions have a profound impact on the experimental outcome and should be considered more carefully in both study design and interstudy comparison.

Effects of Refrigeration and Freezing on the Electromechanical and Biomechanical Properties of Articular Cartilage

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Adele Changoor ◽  
Liah Fereydoonzad ◽  
Alex Yaroshinsky ◽  
Michael D. Buschmann
Keyword(s):  
Articular Cartilage ◽  
Experimental Testing ◽  
Biomechanical Testing ◽  
Biomechanical Properties ◽  
Fresh Tissue ◽  
Testing Procedures ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle

In vitro electromechanical and biomechanical testing of articular cartilage provide critical information about the structure and function of this tissue. Difficulties obtaining fresh tissue and lengthy experimental testing procedures often necessitate a storage protocol, which may adversely affect the functional properties of cartilage. The effects of storage at either 4°C for periods of 6 days and 12 days, or during a single freeze-thaw cycle at −20°C were examined in young bovine cartilage. Non-destructive electromechanical measurements and unconfined compression testing on 3 mm diameter disks were used to assess cartilage properties, including the streaming potential integral (SPI), fibril modulus (Ef), matrix modulus (Em), and permeability (k). Cartilage disks were also examined histologically. Compared with controls, significant decreases in SPI (to 32.3±5.5% of control values, p<0.001), Ef (to 3.1±41.3% of control values, p=0.046), Em (to 6.4±8.5% of control values, p<0.0001), and an increase in k (to 2676.7±2562.0% of control values, p=0.004) were observed at day 12 of refrigeration at 4°C, but no significant changes were detected at day 6. A trend toward detecting a decrease in SPI (to 94.2±6.2% of control values, p=0.083) was identified following a single freeze-thaw cycle, but no detectable changes were observed for any biomechanical parameters. All numbers are mean±95% confidence interval. These results indicate that fresh cartilage can be stored in a humid chamber at 4°C for a maximum of 6 days with no detrimental effects to cartilage electromechanical and biomechanical properties, while one freeze-thaw cycle produces minimal deterioration of biomechanical and electromechanical properties. A comparison to literature suggested that particular attention should be paid to the manner in which specimens are thawed after freezing, specifically by minimizing thawing time at higher temperatures.

Cell-Free Book-Shaped Decellularized Tendon Matrix Graft Capable of Controlled Release of BMP-12 to Improve Tendon Healing in a Rat Model

2021 ◽  
pp. 036354652199455
Author(s):  
Han Xiao ◽  
Yang Chen ◽  
Muzhi Li ◽  
Qiang Shi ◽  
Yan Xu ◽  
...  
Keyword(s):  
Rat Model ◽  
Biomechanical Testing ◽  
Tendon Healing ◽  
Biomechanical Properties ◽  
The Other ◽  
Histological Evaluation ◽  
Sprague Dawley ◽  
A Cell

Background: Achilles tendon (AT) defects often occur in traumatic and chronic injuries. Currently, no graft can satisfactorily regenerate parallel tendinous tissue at the defect site to completely restore AT function. Purpose: To develop a cell-free functional graft by tethering bone morphogenetic protein 12 (BMP-12) on a book-shaped decellularized tendon matrix (BDTM) and to determine whether this graft is more beneficial for AT defect healing than an autograft. Study Design: Controlled laboratory study. Methods: Canine patellar tendon was sectioned into a book shape and decellularized to fabricate a BDTM. The collagen-binding domain (CBD) was fused into the N-terminus of BMP-12 to synthesize a recombinant BMP-12 (CBD-BMP-12), which was tethered to the BDTM to prepare a cell-free functional graft (CBD-BMP-12/BDTM). After its tensile resistance, tenogenic inducibility, and BMP-12 release dynamics were evaluated, the efficacy of the graft for tendon regeneration was determined in a rat model. A total of 140 mature male Sprague-Dawley rats underwent AT tenotomy. The defect was reconstructed with reversed AT (autograft group), native BMP-12 tethered to an intact decellularized tendon matrix (IDTM; NAT-BMP-12/IDTM group), native BMP-12 tethered to a BDTM (NAT-BMP-12/BDTM group), CBD-BMP-12 tethered on an IDTM (CBD-BMP-12/IDTM group), and CBD-BMP-12 tethered on a BDTM (CBD-BMP-12/BDTM group). The rats were sacrificed 4 or 8 weeks after surgery to harvest AT specimens. Six specimens from each group at each time point were used for histological evaluation; the remaining 8 specimens were used for biomechanical testing. Results: In vitro CBD-BMP-12/BDTM was noncytotoxic, showed high biomimetics with native tendons, was suitable for cell adhesion and growth, and had superior tenogenic inducibility. In vivo the defective AT in the CBD-BMP-12/BDTM group regenerated more naturally than in the other groups, as indicated by more spindle-shaped fibroblasts embedded in a matrix of parallel fibers. The biomechanical properties of the regenerated AT in the CBD-BMP-12/BDTM group also increased more significantly than in the other groups. Conclusion: CBD-BMP-12/BDTM is more beneficial than autograft for healing AT defects in a rat model. Clinical Relevance: The findings of this study demonstrate that CBD-BMP-12/BDTM can serve as a practical graft for reconstructing AT defects.

The Tissue Engineering Approach to Ligament Reconstruction

1993 ◽  
Vol 331 ◽  
Author(s):  
Michael G. Dunn ◽  
J. B. Liesch ◽  
M. L. Tiku ◽  
S. H. Maxian ◽  
J. P. Zawadsky
Keyword(s):  
Acl Reconstruction ◽  
Patellar Tendon ◽  
Cruciate Ligament ◽  
Collagen Scaffold ◽  
In Vivo Studies ◽  
Collagen Scaffolds ◽  
Tissue Engineering Approach ◽  
Anterior Cruciate

AbstractPrevious studies in our laboratory showed that acellular collagen scaffold implants induce tissue ingrowth and perform similar to autografts following reconstruction of rabbit Achilles tendon or anterior cruciate ligament (ACL). We chronologically review these and related studies, and report preliminary development of fibroblast-seeded collagen scaffolds potentially useful for ACL reconstruction. The ‘healing potential’ of fibroblasts was measured within collagen scaffolds in vitro, as a function of fibroblast source. Aligned collagen scaffolds were seeded with fibroblasts from rabbit ACL, synovium, patellar tendon, or skin. Fibroblast viability, adherence, spreading, proliferation, and protein and collagen deposition were measured on collagen scaffolds. The fibroblasts attached to the scaffolds, and spread along the long axis of the collagen fibers. ACL fibroblasts adhered better than other fibroblast types; however, the ACL fibroblasts proliferated at the slowest rate. Patellar tendon fibroblasts proliferated at the most rapid rate. All four of the fibroblast types secreted protein and collagen within the collagen scaffolds.Preliminary in vivo studies suggest that fibroblasts seeded onto collagen scaffolds can remain viable following reimplantation into the donor rabbit. Ongoing studies will elucidate the role of autogenous seeded fibroblasts in neoligament formation/remodeling. These ‘ligament analogs’ are potentially useful for clinical ACL reconstruction: fibroblasts would be obtained from biopsy, cultured, seeded onto a collagen scaffold, and implanted as an ACL substitute into the same patient.

Sign in / Sign up

Export Citation Format

Share Document