scholarly journals Electrospun Water-Borne Polyurethane Nanofibrous Membrane as a Barrier for Preventing Postoperative Peritendinous Adhesion

2019 ◽  
Vol 20 (7) ◽  
pp. 1625 ◽  
Author(s):  
Shih-Heng Chen ◽  
Pang-Yun Chou ◽  
Zhi-Yu Chen ◽  
Feng-Huei Lin
Keyword(s):  
Tendon Repair ◽  
Major Complication ◽  
Biomechanical Properties ◽  
Tendon Injury ◽  
Electrospinning Process ◽  
In Vivo Studies ◽  
Surrounding Tissue ◽  
Water Borne

Peritendinous adhesion is a major complication after tendon injury and the subsequent repairs or reconstructions. The degree of adhesion can be reduced by the interposition of a membranous barrier between the traumatized tendon and the surrounding tissue. In the present study, electrospun water-borne polyurethane (WPU) nanofibrous membranes (NFMs) were created for use after the reparation or reconstruction of tendons to reduce adhesion. In the electrospinning process, water was employed as the solvent for WPU, and this solvent was ecofriendly and nontoxic. The nanofibrous architecture and pore size of the WPU NFMs were analyzed. Their microporosity (0.78–1.05 µm) blocked the penetration of fibroblasts, which could result in adhesion and scarring around the tendon during healing. The release of WPU mimicked the lubrication effect of the synovial fluid produced by the synovium around the tendon. In vitro cell studies revealed that the WPU NFMs effectively reduced the number of fibroblasts that became attached and that there was no significant cytotoxicity. In vivo studies with the rabbit flexor tendon repair model revealed that WPU NFMs reduced the degree of peritendinous adhesion, as determined using a gross examination; a histological cross section evaluation; and measurements of the range of motion of interphalangeal joints (97.1 ± 14.7 and 79.0 ± 12.4 degrees in proximal and distal interphalangeal joints respectively), of the length of tendon excursion (11.6 ± 1.9 cm), and of the biomechanical properties.

scholarly journals Hypoxia-Induced Mesenchymal Stem Cells Exhibit Stronger Tenogenic Differentiation Capacities and Promote Patellar Tendon Repair in Rabbits

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Guanyin Chen ◽  
Wangqian Zhang ◽  
Kuo Zhang ◽  
Shuning Wang ◽  
Yuan Gao ◽  
...  
Keyword(s):  
Patellar Tendon ◽  
Tendon Repair ◽  
Biomechanical Properties ◽  
Clinical Results ◽  
Medical Problem ◽  
Tendon Injury ◽  
Tenogenic Differentiation ◽  
Tgf Β1

Tendon injury is a common but tough medical problem. Unsatisfactory clinical results have been reported in tendon repair using mesenchymal stem cell (MSC) therapy, creating a need for a better strategy to induce MSCs to tenogenic differentiation. This study was designed to examine the effect of hypoxia on the tenogenic differentiation of different MSCs and their tenogenic differentiation capacities under hypoxia condition in vitro and to investigate the in vivo inductility of hypoxia in tenogenesis. Adipose tissue-derived MSCs (AMSCs) and bone marrow-derived MSCs (BMSCs) were isolated and characterized. The expression of hypoxia-induced factor-1 alpha (Hif-1α) was examined to confirm the establishment of hypoxia condition. qRT-PCR, western blot, and immunofluorescence staining were used to evaluate the expression of tendon-associated marker Col-1a1, Col-3a1, Dcn, and Tnmd in AMSCs and BMSCs under hypoxia condition, compared with Tgf-β1 induction. In vivo, a patellar tendon injury model was established. Normoxic and hypoxic BMSCs were cultured and implanted. Histological, biomechanical, and transmission electron microscopy analyses were performed to assess the improved healing effect of hypoxic BMSCs on tendon injury. Our in vitro results showed that hypoxia remarkably increased the expression of Hif-1α and that hypoxia not only promoted a significant increase in tenogenic markers in both AMSCs and BMSCs compared with the normoxia group but also showed higher inductility compared with Tgf-β1. In addition, hypoxic BMSCs exhibited higher potential of tenogenic differentiation than hypoxic AMSCs. Our in vivo results demonstrated that hypoxic BMSCs possessed better histological and biomechanical properties than normoxic BMSCs, as evidenced by histological scores, patellar tendon biomechanical parameters, and the range and average of collagen fibril diameters. These findings suggested that hypoxia may be a practical and reliable strategy to induce tenogenic differentiation of BMSCs for tendon repair and could enhance the effectiveness of MSCs therapy in treating tendon injury.

scholarly journals Mkx Mediates Tenogenic Differentiation But Incompletely Inhibits The Proliferation of Hypoxic MSCs

2021 ◽  
Author(s):  
Guanyin Chen ◽  
Dong Fan ◽  
Wangqian Zhang ◽  
Shuning Wang ◽  
Jintao Gu ◽  
...  
Keyword(s):  
Tendon Repair ◽  
Biomechanical Properties ◽  
Tendon Injury ◽  
Cell Counting ◽  
Differentiation Markers ◽  
Proliferation Capacity ◽  
Tenogenic Differentiation ◽  
Differentiation And Proliferation

Abstract Background: Hypoxia has been shown to be able to induce tenogenic differentiation of mesenchymal stem cells (MSCs) which lead hypoxia-induced MSCs to be a potential treatment for tendon injury. However, little is known about the mechanism underlying the tenogenic differentiation process of hypoxic MSCs, which limited the application of differentiation-inducing therapies in tendon repair. This study was designed to investigate the role of Mohawk homeobox (Mkx) in tenogenic differentiation and proliferation of hypoxic MSCs.Methods: Adipose-derived MSCs (AMSCs) and bone marrow-derived MSCs (BMSCs) were isolated, identified and cultured as our previous study. qRT-PCR, western blot, and immunofluorescence staining were performed to evaluate the expression of Mkx and other tendon-associated markers in AMSCs and BMSCs under hypoxia condition. Small interfering RNA technique was applied to observe the effect of Mkx levels on the expression of tendon-associated markers in normoxic and hypoxic BMSCs. Hypoxic BMSCs infected with Mkx-specific short hair RNA (shRNA) or scramble were implanted into the wound gaps of injured patellar tendons to assess the effect of Mkx levels on tendon repair. In addition, cell counting kit‑8 and colony formation unit assays were adopted to determine the proliferation capacity of normoxic or hypoxic BMSCs infected with or without Mkx-specific shRNA.Results: Our data showed that the expression of Mkx significantly increased in hypoxic AMSCs, and increased much more in hypoxic BMSCs. Our results also detected that the expression of tenogenic differentiation markers after down-regulation of Mkx were significantly decreased not only in normoxic BMSCs, but also in hypoxic BMSCs which paralleled the inferior histological evidences, worse biomechanical properties and smaller diameters of collagen fibrils in vivo. In addition, our in vitro data demonstrated that the optical density values and the clone numbers of both normoxic and hypoxic BMSCs were significantly increased after knockdown of Mkx, and were also significantly enhanced in both AMSCs and BMSCs in hypoxia condition under which the expression of Mkx was up-regulated.Conclusions: These findings strongly suggested that Mkx mediated hypoxia-induced tenogenic differentiation of MSCs, but could not completely repress the proliferation of hypoxic MSCs.

scholarly journals Mkx mediates tenogenic differentiation but incompletely inhibits the proliferation of hypoxic MSCs

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guanyin Chen ◽  
Dong Fan ◽  
Wangqian Zhang ◽  
Shuning Wang ◽  
Jintao Gu ◽  
...  
Keyword(s):  
Tendon Repair ◽  
Biomechanical Properties ◽  
Tendon Injury ◽  
Cell Counting ◽  
Differentiation Markers ◽  
Proliferation Capacity ◽  
Tenogenic Differentiation ◽  
Differentiation And Proliferation

Abstract Background Hypoxia has been shown to be able to induce tenogenic differentiation and proliferation of mesenchymal stem cells (MSCs) which lead hypoxia-induced MSCs to be a potential treatment for tendon injury. However, little is known about the mechanism underlying the tenogenic differentiation and proliferation process of hypoxic MSCs, which limited the application of differentiation-inducing therapies in tendon repair. This study was designed to investigate the role of Mohawk homeobox (Mkx) in tenogenic differentiation and proliferation of hypoxic MSCs. Methods qRT-PCR, western blot, and immunofluorescence staining were performed to evaluate the expression of Mkx and other tendon-associated markers in adipose-derived MSCs (AMSCs) and bone marrow-derived MSCs (BMSCs) under hypoxia condition. Small interfering RNA technique was applied to observe the effect of Mkx levels on the expression of tendon-associated markers in normoxic and hypoxic BMSCs. Hypoxic BMSCs infected with Mkx-specific short hair RNA (shRNA) or scramble were implanted into the wound gaps of injured patellar tendons to assess the effect of Mkx levels on tendon repair. In addition, cell counting kit-8 assay, colony formation unit assay, cell cycle analysis, and EdU assay were adopted to determine the proliferation capacity of normoxic or hypoxic BMSCs infected with or without Mkx-specific shRNA. Results Our data showed that the expression of Mkx significantly increased in hypoxic AMSCs and increased much higher in hypoxic BMSCs. Our results also detected that the expression of tenogenic differentiation markers after downregulation of Mkx were significantly decreased not only in normoxic BMSCs, but also in hypoxic BMSCs which paralleled the inferior histological evidences, worse biomechanical properties, and smaller diameters of collagen fibrils in vivo. In addition, our in vitro data demonstrated that the optical density values, the clone numbers, the percentage of cells in S phage, and cell proliferation potential of both normoxic and hypoxic BMSCs were all significantly increased after knockdown of Mkx and were also significantly enhanced in both AMSCs and BMSCs in hypoxia condition under which the expression of Mkx was upregulated. Conclusions These findings strongly suggested that Mkx mediated hypoxia-induced tenogenic differentiation of MSCs but could not completely repress the proliferation of hypoxic MSCs.

scholarly journals Fatty acid is a potential agent for bone tissue induction: In vitro and in vivo approach

2017 ◽  
Vol 242 (18) ◽  
pp. 1765-1771 ◽  
Author(s):  
Guinea BC Cardoso ◽  
Erivelto Chacon ◽  
Priscila GL Chacon ◽  
Pedro Bordeaux-Rego ◽  
Adriana SS Duarte ◽  
...  
Keyword(s):  
Stem Cells ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Bone Tissue ◽  
In Vivo Studies ◽  
Surrounding Tissue ◽  
Bone Induction ◽  
Acid Addition

Our hypothesis was to investigate the fatty acid potential as a bone induction factor. In vitro and in vivo studies were performed to evaluate this approach. Oleic acid was used in a 0.5 wt.% concentration. Polycaprolactone was used as the polymeric matrix by combining solvent-casting and particulate-leaching techniques, with a final porosity of 70 wt.%, investigated by SEM images. Contact angle measurements were produced to investigate the influence of oleic acid on polycaprolactone chains. Cell culture was performed using adipocyte-derived stem cells to evaluate biocompatibility and bioactivity properties. In addition, in vivo studies were performed to evaluate the induction potential of oleic acid addition. Adipocyte-derived stem cells were used to provide differentiation after 21 days of culture. Likewise, information were obtained with in vivo data and cellular invagination was observed on both scaffolds (polycaprolactone and polycaprolactone /oleic acid); interestingly, the scaffold with oleic acid addition demonstrated that cellular migrations are not related to the surrounding tissue, indicating bioactive potential. Our hypothesis is that fatty acid may be used as a potential induction factor for bone tissue engineering. The study’s findings indicate oleic acid as a possible agent for bone induction, according to data on cell differentiation, proliferation, and migration. Impact statement The biomaterial combined in this study on bone regeneration is innovative and shows promising results in the treatment of bone lesions. Polycaprolactone (PCL) and oleic acid have been studied separately. In this research, we combined biomaterials to assess the stimulus and the speed of bone healing.

Hypoxia promotes tenocyte differentiation of mesenchymal stem cells

2020 ◽  
Author(s):  
Guanyin Chen ◽  
wangqian zhang ◽  
Jintao Gu ◽  
Yuan Gao ◽  
Lei He ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Patellar Tendon ◽  
Tendon Repair ◽  
Clinical Results ◽  
Tendon Injury ◽  
Tenogenic Differentiation ◽  
Tgf Β1

Abstract Background: Tendon injury is a common but tough medical problem. Unsatisfactory clinical results have been reported in tendon repair using mesenchymal stem cells (MSCs) therapy, creating a need for a better strategy to induce MSCs to tenogenic differentiation. This study was designed to investigate the role of hypoxia in the tenogenic differentiation of MSCs in vitro and in vivo and to compare the tenogenic differentiation capacities of different MSCs under hypoxia condition in vitro. Methods: Adipose tissue-derived MSCs (AMSCs) and bone marrow-derived MSCs (BMSCs) were isolated and characterized by the expression of MSC-specific markers and tri-lineage differentiation. The expression of hypoxia induced factor-1 alpha (Hif-1α) and the proliferation of AMSCs and BMSCs were examined in order to confirm the establishment of hypoxia condition. qRT-PCR, western blot, and immunofluorescence staining were used to evaluate the expression of tendon-associated marker Col-1a1, Col-3a1, Dcn, and Tnmd in AMSCs and BMSCs under hypoxia and/or Tgf-β1 condition. In vivo, a patellar tendon injury model was established. Normoxic and hypoxic BMSCs were cultured and implanted. Histological, biomechanical and transmission electron microscopy analyses were performed to assess the improved healing effect of hypoxic BMSCs on tendon injury. Results: Hypoxia remarkably increased the expression of Hif-1α and the proliferation of AMSCs and BMSCs. Our in vitro results detected that hypoxia not only promoted a significant increase in tenogenic markers in both AMSCs and BMSCs compared with the normoxia group, but also showed higher inductility compared with Tgf-β1. In addition, hypoxic BMSCs exhibited higher potential of tenogenic differentiation than hypoxic AMSCs. Our in vivo results demonstrated that hypoxic BMSCs possessed better histological and biomechanical properties than those of normoxic BMSCs, as evidenced by histological scores, quantitative analysis of immunohistochemical staining for Col-1a1 and Tnmd, the range and average of collagen fibril diameters and patellar tendon biomechanical tests. Conclusions: These findings suggested that hypoxia may be a practical and reliable strategy to induce tenogenic differentiation of BMSCs for tendon repair and could enhance the effectiveness of MSCs therapy in treating tendon injury.

Trajectory-Based Tissue Engineering for Cartilage Repair: Correlation Between Maturation Rate and Integration Capacity

2013 ◽  
Author(s):  
Matthew B. Fisher ◽  
Nicole Söegaard ◽  
David R. Steinberg ◽  
Robert L. Mauck
Keyword(s):  
Tissue Engineering ◽  
Time Course ◽  
Biomechanical Properties ◽  
Time Dependent ◽  
In Vivo Studies ◽  
Surgical Approaches ◽  
General Hypothesis ◽  
Vitro Assay

Given the limitations of current surgical approaches to treat articular cartilage injuries, tissue engineering (TE) approaches have been aggressively pursued over the past two decades. Although biochemical and biomechanical properties on the order of the native tissue have been achieved (1–5), several in-vitro and in-vivo studies indicate that increased tissue maturity may limit the ability of engineered constructs to remodel and integrate with surrounding cartilage, although results are highly variable (2, 6–8). Thus, “static” measures of construct maturity (e.g. compressive modulus) upon implantation may not be the best indicators of in-vivo success, which likely requires implanted TE constructs to mature, remodel, and integrate with the host over time to achieve optimal results. We recently introduced the concept of “trajectory-based” tissue engineering (TB-TE), which is based on the general hypothesis that time-dependent increases in construct maturation in-vitro prior to implantation (i.e. positive rates) may provide a better predictor of in-vivo success (9). As a first step in evaluating this concept, in the current study we hypothesized that time-dependent increases in equilibrium modulus (a metric of growth) would be correlated to ability of constructs to integrate to cartilage using an in-vitro assay. To test this hypothesis, the current objective was to determine and model the time course of maturation of TE constructs during in-vitro culture and to assess the ability of these constructs to integrate to cartilage at various points during their maturation.

scholarly journals Suturing Achilles tendon and mesh simultaneously in augmented repair resists gap formation foremost: an experimental study

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
William McCartney ◽  
Ciprian Ober ◽  
Maria Benito ◽  
Bryan MacDonald
Keyword(s):  
Achilles Tendon ◽  
Polypropylene Mesh ◽  
Tendon Repair ◽  
Biomechanical Properties ◽  
In Vivo Studies ◽  
Control Group ◽  
Gap Formation ◽  
Achilles Tendon Repair ◽  
Mesh Augmentation

Abstract Background The common calcanean tendon (Achilles tendon) is the strongest and largest tendon and is one of the most commonly affected by spontaneous rupture. Different suture techniques are used to repair the tendon rupture. We compare the biomechanical properties of three different modalities of suture pattern in a mechanical experiment in rabbits with the purpose of evaluating the use of polypropylene mesh augmentation for Achilles tendon repair to find out the best surgical option. Methods The study tests single cycle to failure tensile strength characteristics of three different combinations of the 3-loop pulley (3-LP) suture technique with polypropylene mesh, and statistically compares the biomechanical properties as the maximum load at failure for all 3-LP repair. Results The normal Achilles tendon—control group—failed at a mean load of 25.5 + 13.6; the experimental groups failed at a significantly lower load (p < 0.001), with the group of 3-LP suture with polypropylene mesh included in the suture being the more similar to controls, but all the groups exhibited statistically significant differences with regard to normal tendons (p < 0.001). The distance at which each group failed was also significant between control and experimental groups (p < 0.001) with the exception of the suture-only group and the group with the mesh over the suture (p = 0.15). Conclusion Results from this study suggest that incorporating the mesh within the suture provides benefit to the Achilles tendon repair by improving strength and resistance to pull through. However, further in vivo studies will be necessary to confirm these results and incorporate this technique to the routine human and veterinary surgery.

scholarly journals In Vitro and In Vivo Testing of Zinc as a Biodegradable Material for Stents Fabricated by Photo-Chemical Etching

2019 ◽  
Vol 9 (21) ◽  
pp. 4503 ◽  
Author(s):  
Bala Subramanya Pavan Kumar Kandala ◽  
Guangqi Zhang ◽  
Tracy M. Hopkins ◽  
Xiaoxian An ◽  
Sarah K. Pixley ◽  
...  
Keyword(s):  
Design Patterns ◽  
Chemical Etching ◽  
Surface Oxidation ◽  
Radial Force ◽  
In Vivo Studies ◽  
Surrounding Tissue ◽  
Mice Model ◽  
Parylene C

There is an increasing interest in biodegradable metal implants made from magnesium (Mg), iron (Fe), zinc (Zn) and their alloys because they are well tolerated in vivo and have mechanical properties that approach those of non-degradable metals. In particular, Zn and its alloys show the potential to be the next generation of biodegradable materials for medical implants. However, Zn has not been as well-studied as Mg, especially for stent applications. Manufacturing stents by laser cutting has become an industry standard. Nevertheless, the use of this approach with Zn faces some challenges, such as generating thermal stress, dross sticking on the device, surface oxidation, and the need for expensive thin-walled Zn tubing and post-treatment. All of these challenges motivated us to employ photo-chemical etching for fabricating different designs of Zn (99.95% pure) stents. The stents were constructed with different strut patterns, made by photo-chemical etching, and mechanically tested to evaluate radial forces. Stents with rhombus design patterns showed a promising 0.167N/mm radial force, which was comparable to Mg-based stents. In vitro studies were conducted with uncoated Zn stents as control and Parylene C-coated Zn stents to determine corrosion rates. The Parylene C coating reduced the corrosion rate by 50% compared to uncoated stents. In vivo studies were carried out by implanting photo-chemically etched, uncoated Zn stent segments subcutaneously in a C57BL/6 mice model. Histological analyses provided favorable data about the surrounding tissue status, as well as nerve and blood vessel responses near the implant, providing insights into the in vivo degradation of the metal struts. All of these experiments confirmed that Zn has the potential for use in biodegradable stent applications.

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 Mesenchymal Stem Cells Empowering Tendon Regenerative Therapies

2019 ◽  
Vol 20 (12) ◽  
pp. 3002 ◽  
Author(s):  
Raquel Costa-Almeida ◽  
Isabel Calejo ◽  
Manuela E. Gomes
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Tendon Repair ◽  
Tendon Healing ◽  
In Vivo Studies ◽  
Competent Cell ◽  
Tendon Regeneration ◽  
Regenerative Therapies

Tendon tissues have limited healing capacity. The incidence of tendon injuries and the unsatisfactory functional outcomes of tendon repair are driving the search for alternative therapeutic approaches envisioning tendon regeneration. Cellular therapies aim at delivering adequate, regeneration-competent cell types to the injured tendon and toward ultimately promoting its reconstruction and recovery of functionality. Mesenchymal stem cells (MSCs) either obtained from tendons or from non-tendon sources, like bone marrow (BM-MSCs) or adipose tissue (ASCs), have been receiving increasing attention over the years toward enhancing tendon healing. Evidences from in vitro and in vivo studies suggest MSCs can contribute to accelerate and improve the quality of tendon healing. Nonetheless, the exact mechanisms underlying these repair events are yet to be fully elucidated. This review provides an overview of the main challenges in the field of cell-based regenerative therapies, discussing the role of MSCs in boosting tendon regeneration, particularly through their capacity to enhance the tenogenic properties of tendon resident cells.

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