The Experts below are selected from a list of 19230 Experts worldwide ranked by ideXlab platform
Farshid Guilak - One of the best experts on this subject based on the ideXlab platform.
-
Biomechanics and mechanobiology in Functional Tissue Engineering
Journal of biomechanics, 2014Co-Authors: Farshid Guilak, David L. Butler, Steven A. Goldstein, Frank P.t. BaaijensAbstract:The field of Tissue Engineering continues to expand and mature, and several products are now in clinical use, with numerous other preclinical and clinical studies underway. However, specific challenges still remain in the repair or regeneration of Tissues that serve a predominantly biomechanical function. Furthermore, it is now clear that mechanobiological interactions between cells and scaffolds can critically influence cell behavior, even in Tissues and organs that do not serve an overt biomechanical role. Over the past decade, the field of “Functional Tissue Engineering” has grown as a subfield of Tissue Engineering to address the challenges and questions on the role of biomechanics and mechanobiology in Tissue Engineering. Originally posed as a set of principles and guidelines for Engineering of load-bearing Tissues, Functional Tissue Engineering has grown to encompass several related areas that have proven to have important implications for Tissue repair and regeneration. These topics include measurement and modeling of the in vivo biomechanical environment; quantitative analysis of the mechanical properties of native Tissues, scaffolds, and repair Tissues; development of rationale criteria for the design and assessment of engineered Tissues; investigation of the effects biomechanical factors on native and repair Tissues, in vivo and in vitro; and development and application of computational models of Tissue growth and remodeling. Here we further expand this paradigm and provide examples of the numerous advances in the field over the past decade. Consideration of these principles in the design process will hopefully improve the safety, efficacy, and overall success of engineered Tissue replacements.
-
Functional Tissue Engineering: Ten more years of progress.
Journal of biomechanics, 2014Co-Authors: Farshid Guilak, Frank P.t. BaaijensAbstract:Abstract “Functional Tissue Engineering” is a subset of the field of Tissue Engineering that was proposed by the United States National Committee on Biomechanics over a decade ago in order to place more emphasis on the roles of biomechanics and mechanobiology in Tissue repair and regeneration. Over the past decade, there have been tremendous advances in this area, pointing out the critical role that biomechanical factors can play in the engineered repair of virtually all Tissue and organ systems. In this special issue of the Journal of Biomechanics, we present a series of articles that address a broad array of the fundamental topics of Functional Tissue Engineering, including: (1) measurement and modeling of the in vivo biomechanical environment and history in native and repair Tissues; (2) further understanding of the biomechanical properties of native Tissues across all geometric scales, in the context of repair or regeneration; (3) prioritization of specific biomechanical properties as design criteria; (4) development of biomaterials, scaffolds, and engineered Tissues with prescribed biomechanical properties; (5) development of success criteria based on appropriate outcome measures; (6) investigation of the effects of mechanical factors on Tissue repair in vivo; (7) investigation of the mechanisms by which physical factors may enhance Tissue regeneration in vitro; and (8) development and validation of computational models of Tissue growth and remodeling. These articles represent the tremendous expansion of this field in recent years, and emphasize the critical roles that biomechanics and mechanobiology play in controlling Tissue repair and regeneration.
-
scaffold mediated lentiviral transduction for Functional Tissue Engineering of cartilage
Proceedings of the National Academy of Sciences of the United States of America, 2014Co-Authors: Jonathan M Brunger, Franklin T Moutos, Nguyen P T Huynh, Caitlin M Guenther, Pablo Perezpinera, Johannah Sanchezadams, Charles A Gersbach, Farshid GuilakAbstract:The ability to develop Tissue constructs with matrix composition and biomechanical properties that promote rapid Tissue repair or regeneration remains an enduring challenge in musculoskeletal Engineering. Current approaches require extensive cell manipulation ex vivo, using exogenous growth factors to drive Tissue-specific differentiation, matrix accumulation, and mechanical properties, thus limiting their potential clinical utility. The ability to induce and maintain differentiation of stem cells in situ could bypass these steps and enhance the success of Engineering approaches for Tissue regeneration. The goal of this study was to generate a self-contained bioactive scaffold capable of mediating stem cell differentiation and formation of a cartilaginous extracellular matrix (ECM) using a lentivirus-based method. We first showed that poly-l-lysine could immobilize lentivirus to poly(e-caprolactone) films and facilitate human mesenchymal stem cell (hMSC) transduction. We then demonstrated that scaffold-mediated gene delivery of transforming growth factor β3 (TGF-β3), using a 3D woven poly(e-caprolactone) scaffold, induced robust cartilaginous ECM formation by hMSCs. Chondrogenesis induced by scaffold-mediated gene delivery was as effective as traditional differentiation protocols involving medium supplementation with TGF-β3, as assessed by gene expression, biochemical, and biomechanical analyses. Using lentiviral vectors immobilized on a biomechanically Functional scaffold, we have developed a system to achieve sustained transgene expression and ECM formation by hMSCs. This method opens new avenues in the development of bioactive implants that circumvent the need for ex vivo Tissue generation by enabling the long-term goal of in situ Tissue Engineering.
-
a biomimetic three dimensional woven composite scaffold for Functional Tissue Engineering of cartilage
Nature Materials, 2007Co-Authors: Franklin T Moutos, Lisa E Freed, Farshid GuilakAbstract:A biomimetic three-dimensional woven composite scaffold for Functional Tissue Engineering of cartilage
-
A biomimetic three-dimensional woven composite scaffold for Functional Tissue Engineering of cartilage
Nature materials, 2007Co-Authors: Franklin T Moutos, Lisa E Freed, Farshid GuilakAbstract:Tissue Engineering seeks to repair or regenerate Tissues through combinations of implanted cells, biomaterial scaffolds and biologically active molecules. The rapid restoration of Tissue biomechanical function remains an important challenge, emphasizing the need to replicate structural and mechanical properties using novel scaffold designs. Here we present a microscale 3D weaving technique to generate anisotropic 3D woven structures as the basis for novel composite scaffolds that are consolidated with a chondrocyte-hydrogel mixture into cartilage Tissue constructs. Composite scaffolds show mechanical properties of the same order of magnitude as values for native articular cartilage, as measured by compressive, tensile and shear testing. Moreover, our findings showed that porous composite scaffolds could be engineered with initial properties that reproduce the anisotropy, viscoelasticity and tension-compression nonlinearity of native articular cartilage. Such scaffolds uniquely combine the potential for load-bearing immediately after implantation in vivo with biological support for cell-based Tissue regeneration without requiring cultivation in vitro.
David L. Butler - One of the best experts on this subject based on the ideXlab platform.
-
Biomechanics and mechanobiology in Functional Tissue Engineering
Journal of biomechanics, 2014Co-Authors: Farshid Guilak, David L. Butler, Steven A. Goldstein, Frank P.t. BaaijensAbstract:The field of Tissue Engineering continues to expand and mature, and several products are now in clinical use, with numerous other preclinical and clinical studies underway. However, specific challenges still remain in the repair or regeneration of Tissues that serve a predominantly biomechanical function. Furthermore, it is now clear that mechanobiological interactions between cells and scaffolds can critically influence cell behavior, even in Tissues and organs that do not serve an overt biomechanical role. Over the past decade, the field of “Functional Tissue Engineering” has grown as a subfield of Tissue Engineering to address the challenges and questions on the role of biomechanics and mechanobiology in Tissue Engineering. Originally posed as a set of principles and guidelines for Engineering of load-bearing Tissues, Functional Tissue Engineering has grown to encompass several related areas that have proven to have important implications for Tissue repair and regeneration. These topics include measurement and modeling of the in vivo biomechanical environment; quantitative analysis of the mechanical properties of native Tissues, scaffolds, and repair Tissues; development of rationale criteria for the design and assessment of engineered Tissues; investigation of the effects biomechanical factors on native and repair Tissues, in vivo and in vitro; and development and application of computational models of Tissue growth and remodeling. Here we further expand this paradigm and provide examples of the numerous advances in the field over the past decade. Consideration of these principles in the design process will hopefully improve the safety, efficacy, and overall success of engineered Tissue replacements.
-
Functional Tissue Engineering of tendon: Establishing biological success criteria for improving tendon repair.
Journal of biomechanics, 2013Co-Authors: Andrew P. Breidenbach, Jason T. Shearn, Cynthia Gooch, Steven D. Gilday, Andrea L. Lalley, Nathaniel A. Dyment, David L. ButlerAbstract:Improving tendon repair using Functional Tissue Engineering (FTE) principles has been the focus of our laboratory over the last decade. Although our primary goals were initially focused only on mechanical outcomes, we are now carefully assessing the biological properties of our Tissue-engineered tendon repairs so as to link biological influences with mechanics. However, given the complexities of tendon development and healing, it remains challenging to determine which aspects of tendon biology are the most important to focus on in the context of Tissue Engineering. To address this problem, we have formalized a strategy to identify, prioritize, and evaluate potential biological success criteria for tendon repair. We have defined numerous biological properties of normal tendon relative to cellular phenotype, extracellular matrix and Tissue ultra-structure that we would like to reproduce in our Tissue-engineered repairs and prioritized these biological criteria by examining their relative importance during both normal development and natural tendon healing. Here, we propose three specific biological criteria which we believe are essential for normal tendon function: (1) scleraxis-expressing cells; (2) well-organized and axially-aligned collagen fibrils having bimodal diameter distribution; and (3) a specialized tendon-to-bone insertion site. Moving forward, these biological success criteria will be used in conjunction with our already established mechanical success criteria to evaluate the effectiveness of our Tissue-engineered tendon repairs.
-
Functional Tissue Engineering for Repair of Load-Bearing Musculoskeletal Tissues: History and Perspective
ASME 2011 Summer Bioengineering Conference Parts A and B, 2011Co-Authors: David L. ButlerAbstract:Although who first defined Tissue Engineering and when this event first occurred in the 1980’s were only recently clarified [1], the enthusiasm for this treatment approach cannot be disputed. Traditional treatments have often been inadequate, leading clinicians and basic scientists to seek novel Tissue Engineering strategies using various cell, scaffold and bioreactor strategies (Figure 1). Tissue engineers routinely mix specialized as well as undifferentiated cells from various sources [2] with biologic, synthetic, and even hybrid scaffold biomaterials [3]. Cells can accelerate repair while scaffolds provide the Tissue engineered construct (TEC) with mechanical and structural integrity and guide cell proliferation and differentiation and protein synthesis. Tissue engineers also design and adapt bioreactors to deliver mechanical and chemical stimuli to ensure viability and controlled cell preconditioning [4]. Once implanted, the fate of the repair rests on our ability to achieve desirable mechanical, structural, biological and clinical outcome measures. Unfortunately, many of these “design” or “success” criteria have not been agreed upon nor have the values been determined [5].Copyright © 2011 by ASME
-
The use of mesenchymal stem cells in collagen-based scaffolds for Tissue-engineered repair of tendons
Nature Protocols, 2010Co-Authors: David L. Butler, Jason T. Shearn, Gregory P Boivin, Marc T Galloway, Cynthia Gooch, Nathaniel A. Dyment, Kirsten R C Kinneberg, V Sanjit Nirmalanandhan, Natalia Juncosa-melvinAbstract:Tendon and ligament injuries are significant contributors to musculoskeletal injuries. Unfortunately, traditional methods of repair are not uniformly successful and can require revision surgery. Our research is focused on identifying appropriate animal injury models and using Tissue-engineered constructs (TECs) from bone-marrow-derived mesenchymal stem cells and collagen scaffolds. Critical to this effort has been the development of Functional Tissue Engineering (FTE). We first determine the in vivo mechanical environment acting on the Tissue and then precondition the TECs in culture with aspects of these mechanical signals to improve repair outcome significantly. We describe here a detailed protocol for conducting several complete iterations around our FTE 'road map.' The in vitro portion, from bone marrow harvest to TEC collection, takes 54 d. The in vivo portion, from TEC implantation to limb harvest, takes 84 d. One complete loop around the Tissue Engineering road map, as presented here, takes 138 d to complete.
-
Using Functional Tissue Engineering and Bioreactors to Mechanically Stimulate Tissue-Engineered Constructs
Tissue Engineering Part A, 2009Co-Authors: David L. Butler, Jason T. Shearn, Shawn A. Hunter, Kumar Chokalingam, Michael J. Cordray, Natalia Juncosa-melvin, Sanjit Nirmalanandhan, Abhishek JainAbstract:Bioreactors precondition Tissue-engineered constructs (TECs) to improve integrity and hopefully repair. In this paper, we use Functional Tissue Engineering to suggest criteria for preconditioning TECs. Bioreactors should (1) control environment during mechanical stimulation; (2) stimulate multiple constructs with identical or individual waveforms; (3) deliver precise displacements, including those that mimic in vivo activities of daily living (ADLs); and (4) adjust displacement patterns based on reaction loads and biological activity. We apply these criteria to three bioreactors. We have placed a pneumatic stimulator in a conventional incubator and stretched four constructs in each of five silicone dishes. We have also programmed displacement-limited stimuli that replicate frequencies and peak in vivo patellar tendon (PT) strains. Cellular activity can be monitored from spent media. However, our design prevents direct TEC force measurement. We have improved TEC stiffness as well as PT repair stiffness and...
Savio L. C. Woo - One of the best experts on this subject based on the ideXlab platform.
-
Revolutionizing orthopaedic biomaterials: The potential of biodegradable and bioresorbable magnesium-based materials for Functional Tissue Engineering
Journal of biomechanics, 2013Co-Authors: Kathryn F. Farraro, Savio L. C. Woo, Kwang E. Kim, Jonquil R. Flowers, Matthew B. A. McculloughAbstract:In recent years, there has been a surge of interest in magnesium (Mg) and its alloys as biomaterials for orthopaedic applications, as they possess desirable mechanical properties, good biocompatibility, and biodegradability. Also shown to be osteoinductive, Mg-based materials could be particularly advantageous in Functional Tissue Engineering to improve healing and serve as scaffolds for delivery of drugs, cells, and cytokines. In this paper, we will present two examples of Mg-based orthopaedic devices: an interference screw to accelerate ACL graft healing and a ring to aid in the healing of an injured ACL. In vitro tests using a robotic/UFS testing system showed that both devices could restore function of the goat stifle joint. Under a 67-N anterior tibial load, both the ACL graft fixed with the Mg-based interference screw and the Mg-based ring-repaired ACL could restore anterior tibial translation (ATT) to within 2mm and 5mm, respectively, of the intact joint at 30°, 60°, and 90° of flexion. In-situ forces in the replacement graft and Mg-based ring-repaired ACL were also similar to those of the intact ACL. Further, early in vivo data using the Mg-based interference screw showed that after 12 weeks, it was non-toxic and the joint stability and graft function reached similar levels as published data. Following these positive results, we will move forward in incorporating bioactive molecules and ECM bioscaffolds to these Mg-based biomaterials to test their potential for Functional Tissue Engineering of musculoskeletal and other Tissues.
-
Functional Tissue Engineering of Ligament and Tendon Injuries
Principles of Regenerative Medicine, 2011Co-Authors: Savio L. C. Woo, Rui Liang, Alejandro J. Almarza, Sinan Karaoglu, Matthew B. FisherAbstract:This chapter reviews the properties of normal and healing ligaments and tendons and discusses the current Functional Tissue Engineering (FTE) methods, which include the use of growth factors, gene delivery, stem cell therapy, and the use of scaffolding as well as external mechanical stimuli, aimed at enhancing tendon and ligament healing. The major function of ligaments and tendons include maintaining the proper anatomical alignment of the skeleton and guiding joint motions. They accomplish this by transmitting forces along their longitudinal axis but their biomechanical properties are measured in uniaxial tension. They demonstrate nonlinear behavior, which is governed by the recruitment of collagen. This allows ligaments to maintain normal joint laxity in response to low loads and also to stiffen dramatically in response to high loads, preventing excessive joint displacements. The events of healing of ligaments and tendons are divided into four overlapping phases: hemorrhage, inflammation, repair (proliferation), and remodeling. Following injury, the hemorrhagic and inflammatory phases occur over the first several days. Minutes after the ligament injury, blood collects and forms a platelet-rich fibrin clot at the injury site. The hemorrhage phase of the injury forms a lattice for many following cellular events. FTE has generated many significant developments; for example, there is a class of biodegradable metallic scaffolds, namely porous magnesium or magnesium oxide, that have the advantage of initial stiffness to provide the needed stability for the ligament to heal while performing its function. The degradation rate of these “smart” scaffolds could also be controlled as they are replaced by the neoTissue.
-
Use of Extracellular Matrix Bioscaffolds to Enhance ACL Healing: A Multidisciplinary Approach in a Goat Model
ASME 2010 Summer Bioengineering Conference Parts A and B, 2010Co-Authors: Matthew B. Fisher, Rui Liang, Ho-joong Jung, Patrick J. Mcmahon, Kwang Kim, Savio L. C. WooAbstract:Due to the poor healing potential of the anterior cruciate ligament (ACL) of the knee, surgical reconstruction using soft Tissue replacement grafts is performed to restore knee stability and function. However, the surgery has serious complications including a high incidence of donor site morbidity and the development of osteoarthritis in the long-term. Recently, Functional Tissue Engineering approaches to heal an injured ACL using biological stimulation via growth factors and bioscaffolds have yielded some positive clinical and laboratory results. As the healing process for the ACL is slow, additional suture repair of the ACL has been needed to provide initial joint stability and to reduce the risk of injury to neighboring Tissues.Copyright © 2010 by ASME
-
Functional Tissue Engineering of ligament healing
Sports medicine arthroscopy rehabilitation therapy & technology : SMARTT, 2010Co-Authors: Shan-ling Hsu, Rui Liang, Savio L. C. WooAbstract:Ligaments and tendons are dense connective Tissues that are important in transmitting forces and facilitate joint articulation in the musculoskeletal system. Their injury frequency is high especially for those that are Functional important, like the anterior cruciate ligament (ACL) and medial collateral ligament (MCL) of the knee as well as the glenohumeral ligaments and the rotator cuff tendons of the shoulder. Because the healing responses are different in these ligaments and tendons after injury, the consequences and treatments are Tissue- and site-specific. In this review, we will elaborate on the injuries of the knee ligaments as well as using Functional Tissue Engineering (FTE) approaches to improve their healing. Specifically, the ACL of knee has limited capability to heal, and results of non-surgical management of its midsubstance rupture have been poor. Consequently, surgical reconstruction of the ACL is regularly performed to gain knee stability. However, the long-term results are not satisfactory besides the numerous complications accompanied with the surgeries. With the rapid development of FTE, there is a renewed interest in revisiting ACL healing. Approaches such as using growth factors, stem cells and scaffolds have been widely investigated. In this article, the biology of normal and healing ligaments is first reviewed, followed by a discussion on the issues related to the treatment of ACL injuries. Afterwards, current promising FTE methods are presented for the treatment of ligament injuries, including the use of growth factors, gene delivery, and cell therapy with a particular emphasis on the use of ECM bioscaffolds. The challenging areas are listed in the future direction that suggests where collection of energy could be placed in order to restore the injured ligaments and tendons structurally and Functionally.
-
Effects of Tunnel Location for Suture Augmentation Following Anterior Cruciate Ligament Injury
ASME 2009 Summer Bioengineering Conference Parts A and B, 2009Co-Authors: Matthew B. Fisher, Ho-joong Jung, Patrick J. Mcmahon, Savio L. C. WooAbstract:The anterior cruciate ligament (ACL) of the knee is frequently injured, but it has limited healing potential. Surgical reconstruction using soft Tissue autografts is often required for active patients. However, about 20–25% of patients have less than satisfactory results and some even developed of osteoarthritis in the long-term. Thus, there is a need for alternative approaches. With advances in Functional Tissue Engineering, healing of the ACL using growth factors and/or bioscaffolds has generated new clinical interests [1].Copyright © 2009 by ASME
Steven D Abramowitch - One of the best experts on this subject based on the ideXlab platform.
-
long term effects of porcine small intestine submucosa on the healing of medial collateral ligament a Functional Tissue Engineering study
Journal of Orthopaedic Research, 2006Co-Authors: Rui Liang, Yoshiyuki Takakura, Daniel K Moon, Steven D AbramowitchAbstract:Porcine small intestinal submucosa (SIS) was previously shown to enhance the mechanical properties of healing medial collateral ligaments (MCL), and the histomorphological appearance and collagen type V/I ratio were found to be close to those of normal MCL. We hypothesized that at a longer term, 26 weeks, SIS could guide a better organized neo-ligament formation, increasing mechanical properties and increasing collagen fibril diameters mediated by a reduction in collagen type V. A 6 mm gap injury in the right MCL was surgically created in 38 rabbits, while the contralateral intact MCL served as a sham-operated control. In half the animals, a strip of SIS was sutured onto the severed ends. In the other half, no SIS was applied. The cross-sectional area (CSA) was determined with a laser micrometer system. The femur–MCL–tibia complex was mechanically tested in uniaxial tension. Histomorphology was determined through H&E and immunofluorescent staining and transmission electron microscopy (TEM). Sodium-dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was used to determine collagen type V/I ratio. SIS-treated MCLs displayed a 28% reduction in CSA, a 33% increase in tangent modulus, and a 50% increase in tensile strength compared with the nontreated group (p < 0.05). TEM showed groups of collagen fibrils with larger diameters in the SIS-treated ligaments in comparison with uniformly small fibrils for the nontreated group. H&E staining showed more densely stained collagen fibers in the SIS-treated group aligned along the longitudinal axis with more interspersed spindle-shaped cells. Immunofluorescent staining showed less collagen type V signals, confirmed by a 5% lower ratio of collagen type V/I compared with the nontreated controls (p < 0.05). The findings extend the shorter term 12-week results, and support the potential of porcine SIS as a bioscaffold to enhance ligament healing. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
-
long term effects of porcine small intestine submucosa on the healing of medial collateral ligament a Functional Tissue Engineering study
Journal of Orthopaedic Research, 2006Co-Authors: Rui Liang, Savio L. C. Woo, Fengyan Jia, Yoshiyuki Takakura, Daniel K Moon, Steven D AbramowitchAbstract:Porcine small intestinal submucosa (SIS) was previously shown to enhance the mechanical properties of healing medial collateral ligaments (MCL), and the histomorphological appearance and collagen type V/I ratio were found to be close to those of normal MCL. We hypothesized that at a longer term, 26 weeks, SIS could guide a better organized neo-ligament formation, increasing mechanical properties and increasing collagen fibril diameters mediated by a reduction in collagen type V. A 6 mm gap injury in the right MCL was surgically created in 38 rabbits, while the contralateral intact MCL served as a sham-operated control. In half the animals, a strip of SIS was sutured onto the severed ends. In the other half, no SIS was applied. The cross-sectional area (CSA) was determined with a laser micrometer system. The femur-MCL-tibia complex was mechanically tested in uniaxial tension. Histomorphology was determined through H&E and immunofluorescent staining and transmission electron microscopy (TEM). Sodium-dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was used to determine collagen type V/I ratio. SIS-treated MCLs displayed a 28% reduction in CSA, a 33% increase in tangent modulus, and a 50% increase in tensile strength compared with the nontreated group (p < 0.05). TEM showed groups of collagen fibrils with larger diameters in the SIS-treated ligaments in comparison with uniformly small fibrils for the nontreated group. H&E staining showed more densely stained collagen fibers in the SIS-treated group aligned along the longitudinal axis with more interspersed spindle-shaped cells. Immunofluorescent staining showed less collagen type V signals, confirmed by a 5% lower ratio of collagen type V/I compared with the nontreated controls (p < 0.05). The findings extend the shorter term 12-week results, and support the potential of porcine SIS as a bioscaffold to enhance ligament healing.
-
Long‐term effects of porcine small intestine submucosa on the healing of medial collateral ligament: A Functional Tissue Engineering study
Journal of orthopaedic research : official publication of the Orthopaedic Research Society, 2006Co-Authors: Rui Liang, Savio L. C. Woo, Fengyan Jia, Yoshiyuki Takakura, Daniel K Moon, Steven D AbramowitchAbstract:Porcine small intestinal submucosa (SIS) was previously shown to enhance the mechanical properties of healing medial collateral ligaments (MCL), and the histomorphological appearance and collagen type V/I ratio were found to be close to those of normal MCL. We hypothesized that at a longer term, 26 weeks, SIS could guide a better organized neo-ligament formation, increasing mechanical properties and increasing collagen fibril diameters mediated by a reduction in collagen type V. A 6 mm gap injury in the right MCL was surgically created in 38 rabbits, while the contralateral intact MCL served as a sham-operated control. In half the animals, a strip of SIS was sutured onto the severed ends. In the other half, no SIS was applied. The cross-sectional area (CSA) was determined with a laser micrometer system. The femur-MCL-tibia complex was mechanically tested in uniaxial tension. Histomorphology was determined through H&E and immunofluorescent staining and transmission electron microscopy (TEM). Sodium-dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was used to determine collagen type V/I ratio. SIS-treated MCLs displayed a 28% reduction in CSA, a 33% increase in tangent modulus, and a 50% increase in tensile strength compared with the nontreated group (p < 0.05). TEM showed groups of collagen fibrils with larger diameters in the SIS-treated ligaments in comparison with uniformly small fibrils for the nontreated group. H&E staining showed more densely stained collagen fibers in the SIS-treated group aligned along the longitudinal axis with more interspersed spindle-shaped cells. Immunofluorescent staining showed less collagen type V signals, confirmed by a 5% lower ratio of collagen type V/I compared with the nontreated controls (p < 0.05). The findings extend the shorter term 12-week results, and support the potential of porcine SIS as a bioscaffold to enhance ligament healing.
-
the use of porcine small intestinal submucosa to enhance the healing of the medial collateral ligament a Functional Tissue Engineering study in rabbits
Journal of Orthopaedic Research, 2004Co-Authors: Volker Musahl, Steven D Abramowitch, Thomas W Gilbert, Eiichi Tsuda, James H C Wang, Stephen F Badylak, Savio L. C. WooAbstract:Introduction: Small intestinal submucosa (SIS) from porcine has been successfully used as a collagen scaffold for the repair of various Tissues, including those of the human vascular, urogenital, and musculoskeletal systems. The objective of this study was to evaluate whether SIS can be used to enhance the healing process of a medial collateral ligament (MCL) with a gap injury in a rabbit model. Methods: A 6 mm wide gap was surgically created in the right MCL of 20 skeletally mature, female New Zealand White rabbits. In 10 rabbits, a strip of SIS was sutured onto the two ends of the MCL, while for the other 10 animals their injured MCL remained untreated and served as a non-treated group. The left MCL of all animals was exposed and undermined serving as the sham-operated side. At 12 weeks post-healing, eight hind limbs from each group were used for mechanical testing. The cross-sectional areas (CSA) of the MCLs were measured. The femur–MCL–tibia complex (FMTC) was tensile tested to failure. The load–elongation curves representing the structural properties of the FMTC and the stress–strain curves representing the mechanical properties of the healing MCL were obtained. The remaining two animals from each group were prepared for histological evaluation. Results: The CSA between the SIS-treated and non-treated groups were not significantly different (p>0.05). Both treatment groups appeared to increase by nearly 40% compared to the sham-operated side, although statistical significance was not found for the non-treated group (p>0.05). The stiffness of the FMTC from the SIS-treated group was 56% higher than the non-treated group (45.7 ± 13.3 N/mm vs. 29.2 ± 9.2 N/mm, respectively, p<0.05) and the ultimate load also nearly doubled (117.434.5 N vs. 66.4 ± 31.4 N, respectively, p<0.05). These values were lower compared to the sham-operated side (89.7 ± 15.3 N/mm and 332.0 ± 50.8 N, respectively). The tangent modulus of the healing MCL (279.7 ± 132.1 MPa vs. 149.0 ± 76.5 MPa, respectively) and stress at failure (15.7 ± 4.1 MPa vs. 10.2 ± 3.9 MPa, respectively) both increased by more than 50% with SIS treatment (p<0.05). Yet, each remained lower compared to the sham-operated side (936.3 ± 283.6 MPa and 75.6 ± 14.2 MPa, respectively). Blinded histological comparisons between the SIS-treated MCL and the non-treated control demonstrated qualitatively that the SIS treated group had increased cellularity, greater collagen density, and improved collagen fiber alignment. Conclusion: Healing of a gap MCL injury was significantly enhanced with SIS. The improved mechanical properties and histological appearance of the MCL suggest that SIS treatment improves the quality of Tissue and renders the possibility for future studies investigating Functional Tissue Engineering of healing ligaments.
-
The use of porcine small intestinal submucosa to enhance the healing of the medial collateral ligament––a Functional Tissue Engineering study in rabbits
Journal of orthopaedic research : official publication of the Orthopaedic Research Society, 2004Co-Authors: Volker Musahl, Steven D Abramowitch, Thomas W Gilbert, Eiichi Tsuda, James H C Wang, Stephen F Badylak, Savio L. C. WooAbstract:Introduction: Small intestinal submucosa (SIS) from porcine has been successfully used as a collagen scaffold for the repair of various Tissues, including those of the human vascular, urogenital, and musculoskeletal systems. The objective of this study was to evaluate whether SIS can be used to enhance the healing process of a medial collateral ligament (MCL) with a gap injury in a rabbit model. Methods: A 6 mm wide gap was surgically created in the right MCL of 20 skeletally mature, female New Zealand White rabbits. In 10 rabbits, a strip of SIS was sutured onto the two ends of the MCL, while for the other 10 animals their injured MCL remained untreated and served as a non-treated group. The left MCL of all animals was exposed and undermined serving as the sham-operated side. At 12 weeks post-healing, eight hind limbs from each group were used for mechanical testing. The cross-sectional areas (CSA) of the MCLs were measured. The femur–MCL–tibia complex (FMTC) was tensile tested to failure. The load–elongation curves representing the structural properties of the FMTC and the stress–strain curves representing the mechanical properties of the healing MCL were obtained. The remaining two animals from each group were prepared for histological evaluation. Results: The CSA between the SIS-treated and non-treated groups were not significantly different (p>0.05). Both treatment groups appeared to increase by nearly 40% compared to the sham-operated side, although statistical significance was not found for the non-treated group (p>0.05). The stiffness of the FMTC from the SIS-treated group was 56% higher than the non-treated group (45.7 ± 13.3 N/mm vs. 29.2 ± 9.2 N/mm, respectively, p
Clark T Hung - One of the best experts on this subject based on the ideXlab platform.
-
Differences in Engineered Cartilage From Human Chondrocytes and Mesenchymal Stem Cells in Pellet and Construct Culture
Volume 1A: Abdominal Aortic Aneurysms; Active and Reactive Soft Matter; Atherosclerosis; BioFluid Mechanics; Education; Biotransport Phenomena; Bone J, 2013Co-Authors: Grace D. O'connell, Victoria Cui, Glyn D. Palmer, Clark T HungAbstract:Articular cartilage serves as the load-bearing material of joints. One approach to Functional Tissue Engineering is to recapitulate the biochemical and mechanical function of healthy native cartilage in vitro, prior to implantation. We have been successful in cultivating engineered cartilage with compressive mechanical properties and glycosaminoglycan (GAG) content near native values by encapsulating chondrocytes or stem cells in a clinically relevant hydrogel [1, 2]. Clinical application of Functional engineered cartilage will likely use of chondrocytes (AC) from osteoarthritic Tissue or mesenchymal stem cells (MSCs), which have been shown to have chondrogenic potential. That is, it is may be more feasible to differentiate healthy MSCs towards a chondrogenic lineage than to ‘reprogram’ ACs acquired from an osteoarthritic joint.Copyright © 2013 by ASME
-
differences in engineered cartilage from human chondrocytes and mesenchymal stem cells in pellet and construct culture
Volume 1A: Abdominal Aortic Aneurysms; Active and Reactive Soft Matter; Atherosclerosis; BioFluid Mechanics; Education; Biotransport Phenomena; Bone J, 2013Co-Authors: Grace D Oconnell, G Palmer, Clark T HungAbstract:Articular cartilage serves as the load-bearing material of joints. One approach to Functional Tissue Engineering is to recapitulate the biochemical and mechanical function of healthy native cartilage in vitro, prior to implantation. We have been successful in cultivating engineered cartilage with compressive mechanical properties and glycosaminoglycan (GAG) content near native values by encapsulating chondrocytes or stem cells in a clinically relevant hydrogel [1, 2]. Clinical application of Functional engineered cartilage will likely use of chondrocytes (AC) from osteoarthritic Tissue or mesenchymal stem cells (MSCs), which have been shown to have chondrogenic potential. That is, it is may be more feasible to differentiate healthy MSCs towards a chondrogenic lineage than to ‘reprogram’ ACs acquired from an osteoarthritic joint.Copyright © 2013 by ASME
-
Dynamic Mechanical Loading Enhances Functional Properties of Tissue-Engineered Cartilage Using Mature Canine Chondrocytes
Tissue engineering. Part A, 2010Co-Authors: Liming Bian, Eric G. Lima, Gerard A. Ateshian, Aaron M. Stoker, James L. Cook, Jason Fong, Clark T HungAbstract:Objective: The concept of cartilage Functional Tissue Engineering (FTE) has promoted the use of physiologic loading bioreactor systems to cultivate engineered Tissues with load-bearing properties. Prior studies have demonstrated that culturing agarose constructs seeded with primary bovine chondrocytes from immature joints, and subjected to dynamic deformation, produced equilibrium compressive properties and proteoglycan content matching the native Tissue. In the process of translating these results to an adult canine animal model, it was found that protocols previously successful with immature bovine primary chondrocytes did not produce the same successful outcome when using adult canine primary chondrocytes. The objective of this study was to assess the efficacy of a modified FTE protocol using adult canine chondrocytes seeded in agarose hydrogel and subjected to dynamic loading. Method: Two modes of dynamic loading were applied to constructs using custom bioreactors: unconfined axial compressive deforma...
-
Functional Tissue Engineering of Articular Cartilage With Adult Chondrocytes
ASME 2009 Summer Bioengineering Conference Parts A and B, 2009Co-Authors: Liming Bian, Eric G. Lima, Gerard A. Ateshian, Prakash S. Jayabalan, Aaron M. Stoker, James L. Cook, Clark T HungAbstract:The concept of cartilage Functional Tissue Engineering (FTE) has promoted the use of physiologic loading bioreactor systems to cultivate engineered Tissues with load-bearing properties [1]. Prior studies have demonstrated that culturing agarose constructs seeded with primary bovine chondrocytes from immature joints, and subjected to dynamic deformation, produced equilibrium compressive properties and proteoglycan content matching the native Tissue [2]. In the process of translating these results to an adult canine animal model, it was found that protocols previously successful with immature bovine primary chondrocytes did not produce the same successful outcome when using adult canine primary chondrocytes [3]. The objective of this study was to assess the efficacy of a modified FTE protocol using adult (canine) chondrocyte-seeded hydrogel constructs and applied dynamic loading.Copyright © 2009 by ASME
-
a paradigm for Functional Tissue Engineering of articular cartilage via applied physiologic deformational loading
Annals of Biomedical Engineering, 2004Co-Authors: Clark T Hung, Eric G. Lima, Robert L. Mauck, Christopher C B Wang, Gerard A. AteshianAbstract:Deformational loading represents a primary component of the chondrocyte physical environment in vivo. This review summarizes our experience with physiologic deformational loading of chondrocyte-seeded agarose hydrogels to promote development of cartilage constructs having mechanical properties matching that of the parent calf Tissue, which has a Young's modulus EY = 277 kPa and unconfined dynamic modulus at 1 Hz G*=7 MPa. Over an 8-week culture period, cartilage-like properties have been achieved for 60 × 106 cells/ml seeding density agarose constructs, with EY = 186 kPa, G*=1.64 MPa. For these constructs, the GAG content reached 1.74% ww and collagen content 2.64% ww compared to 2.4% ww and 21.5% ww for the parent Tissue, respectively. Issues regarding the deformational loading protocol, cell-seeding density, nutrient supply, growth factor addition, and construct mechanical characterization are discussed. In anticipation of cartilage repair studies, we also describe early efforts to engineer cylindrical and anatomically shaped bilayered constructs of agarose hydrogel and bone (i.e., osteochondral constructs). The presence of a bony substrate may facilitate integration upon implantation. These efforts will provide an underlying framework from which a Functional Tissue-Engineering approach, as described by Butler and coworkers (2000), may be applied to general cell-scaffold systems adopted for cartilage Tissue Engineering.
