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Chen K, Liu Z, Zhou X, Zheng W, Cao H, Yang Z, Wang Z, Ning C, Li Q, Zhao H. Hierarchy Reproduction: Multiphasic Strategies for Tendon/Ligament-Bone Junction Repair. Biomater Res 2025; 29:0132. [PMID: 39844867 PMCID: PMC11751208 DOI: 10.34133/bmr.0132] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2024] [Revised: 11/15/2024] [Accepted: 12/17/2024] [Indexed: 01/24/2025] Open
Abstract
Tendon/ligament-bone junctions (T/LBJs) are susceptible to damage during exercise, resulting in anterior cruciate ligament rupture or rotator cuff tear; however, their intricate hierarchical structure hinders self-regeneration. Multiphasic strategies have been explored to fuel heterogeneous tissue regeneration and integration. This review summarizes current multiphasic approaches for rejuvenating functional gradients in T/LBJ healing. Synthetic, natural, and organism-derived materials are available for in vivo validation. Both discrete and gradient layouts serve as sources of inspiration for organizing specific cues, based on the theories of biomaterial topology, biochemistry, mechanobiology, and in situ delivery therapy, which form interconnected network within the design. Novel engineering can be constructed by electrospinning, 3-dimensional printing, bioprinting, textiling, and other techniques. Despite these efforts being limited at present stage, multiphasic scaffolds show great potential for precise reproduction of native T/LBJs and offer promising solutions for clinical dilemmas.
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Affiliation(s)
- Kaiting Chen
- Academy of Orthopedics, Guangdong Province, Orthopedic Hospital of Guangdong Province,
The Third Affiliated Hospital of Southern Medical University, Guangzhou 510665, P. R. China
| | - Zezheng Liu
- Academy of Orthopedics, Guangdong Province, Orthopedic Hospital of Guangdong Province,
The Third Affiliated Hospital of Southern Medical University, Guangzhou 510665, P. R. China
| | - Xinying Zhou
- Academy of Orthopedics, Guangdong Province, Orthopedic Hospital of Guangdong Province,
The Third Affiliated Hospital of Southern Medical University, Guangzhou 510665, P. R. China
| | - Wanyu Zheng
- School of Pharmaceutical Sciences,
Southern Medical University, Guangzhou, Guangdong 510515, P. R. China
| | - He Cao
- Academy of Orthopedics, Guangdong Province, Orthopedic Hospital of Guangdong Province,
The Third Affiliated Hospital of Southern Medical University, Guangzhou 510665, P. R. China
| | - Zijian Yang
- Academy of Orthopedics, Guangdong Province, Orthopedic Hospital of Guangdong Province,
The Third Affiliated Hospital of Southern Medical University, Guangzhou 510665, P. R. China
| | - Zhengao Wang
- School of Materials Science and Engineering,
South China University of Technology, Guangzhou 510006, P. R. China
| | - Chengyun Ning
- School of Materials Science and Engineering,
South China University of Technology, Guangzhou 510006, P. R. China
| | - Qingchu Li
- Academy of Orthopedics, Guangdong Province, Orthopedic Hospital of Guangdong Province,
The Third Affiliated Hospital of Southern Medical University, Guangzhou 510665, P. R. China
| | - Huiyu Zhao
- Academy of Orthopedics, Guangdong Province, Orthopedic Hospital of Guangdong Province,
The Third Affiliated Hospital of Southern Medical University, Guangzhou 510665, P. R. China
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2
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Troop LD, Puetzer JL. Intermittent cyclic stretch of engineered ligaments drives hierarchical collagen fiber maturation in a dose- and organizational-dependent manner. Acta Biomater 2024; 185:296-311. [PMID: 39025395 PMCID: PMC11381169 DOI: 10.1016/j.actbio.2024.07.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 07/10/2024] [Accepted: 07/11/2024] [Indexed: 07/20/2024]
Abstract
Hierarchical collagen fibers are the primary source of strength in tendons and ligaments; however, these fibers largely do not regenerate after injury or with repair, resulting in limited treatment options. We previously developed a static culture system that guides ACL fibroblasts to produce native-sized fibers and early fascicles by 6 weeks. These constructs are promising ligament replacements, but further maturation is needed. Mechanical cues are critical for development in vivo and in engineered tissues; however, the effect on larger fiber and fascicle formation is largely unknown. Our objective was to investigate whether intermittent cyclic stretch, mimicking rapid muscle activity, drives further maturation in our system to create stronger engineered replacements and to explore whether cyclic loading has differential effects on cells at different degrees of collagen organization to better inform engineered tissue maturation protocols. Constructs were loaded with an established intermittent cyclic loading regime at 5 or 10 % strain for up to 6 weeks and compared to static controls. Cyclic loading drove cells to increase hierarchical collagen organization, collagen crimp, and tissue tensile properties, ultimately producing constructs that matched or exceeded immature ACL properties. Further, the effect of loading on cells varied depending on degree of organization. Specifically, 10 % load drove early improvements in tensile properties and composition, while 5 % load was more beneficial later in culture, suggesting a shift in mechanotransduction. This study provides new insight into how cyclic loading affects cell-driven hierarchical fiber formation and maturation, which will help to develop better rehabilitation protocols and engineer stronger replacements. STATEMENT OF SIGNIFICANCE: Collagen fibers are the primary source of strength and function in tendons and ligaments throughout the body. These fibers have limited regenerate after injury, with repair, and in engineered replacements, reducing treatment options. Cyclic load has been shown to improve fibril level alignment, but its effect at the larger fiber and fascicle length-scale is largely unknown. Here, we demonstrate intermittent cyclic loading increases cell-driven hierarchical fiber formation and tissue mechanics, producing engineered replacements with similar organization and mechanics as immature ACLs. This study provides new insight into how cyclic loading affects cell-driven fiber maturation. A better understanding of how mechanical cues regulate fiber formation will help to develop better engineered replacements and rehabilitation protocols to drive repair after injury.
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Affiliation(s)
- Leia D Troop
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States
| | - Jennifer L Puetzer
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States; Department of Orthopaedic Surgery, Virginia Commonwealth University, Richmond, VA 23284, United States.
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3
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Troop LD, Puetzer JL. Intermittent Cyclic Stretch of Engineered Ligaments Drives Hierarchical Collagen Fiber Maturation in a Dose- and Organizational-Dependent Manner. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.06.588420. [PMID: 38645097 PMCID: PMC11030411 DOI: 10.1101/2024.04.06.588420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Hierarchical collagen fibers are the primary source of strength in tendons and ligaments, however these fibers do not regenerate after injury or with repair, resulting in limited treatment options. We previously developed a culture system that guides ACL fibroblasts to produce native-sized fibers and fascicles by 6 weeks. These constructs are promising ligament replacements, but further maturation is needed. Mechanical cues are critical for development in vivo and in engineered tissues; however, the effect on larger fiber and fascicle formation is largely unknown. Our objective was to investigate whether intermittent cyclic stretch, mimicking rapid muscle activity, drives further maturation in our system to create stronger engineered replacements and to explore whether cyclic loading has differential effects on cells at different degrees of collagen organization to better inform engineered tissue maturation protocols. Constructs were loaded with an established intermittent cyclic loading regime at 5 or 10% strain for up to 6 weeks and compared to static controls. Cyclic loading drove cells to increase hierarchical collagen organization, collagen crimp, and tissue mechanics, ultimately producing constructs that matched or exceeded immature ACL properties. Further, the effect of loading on cells varied depending on degree of organization. Specifically, 10% load drove early improvements in mechanics and composition, while 5% load was more beneficial later in culture, suggesting a cellular threshold response and a shift in mechanotransduction. This study provides new insight into how cyclic loading affects cell-driven hierarchical fiber formation and maturation, which will help to develop better rehabilitation protocols and engineer stronger replacements.
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Affiliation(s)
- Leia D. Troop
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, 23284, United States
| | - Jennifer L. Puetzer
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, 23284, United States
- Department of Orthopaedic Surgery, Virginia Commonwealth University, Richmond, VA, 23284, United States
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4
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Chen Y, Gong T, Jiang N, Zhao A, Wang T, Wang X, Han W. Dynamics analysis of the anterior cruciate ligament reconstruction surgery based on magnetic resonance imaging. Biotechnol Genet Eng Rev 2024; 40:576-588. [PMID: 36877599 DOI: 10.1080/02648725.2023.2186324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 02/23/2023] [Indexed: 03/07/2023]
Abstract
In clinical practice, anterior cruciate ligament (ACL) rupture is always repaired by the single-beam reconstruction method. Before the surgery, the surgeon made the diagnosis based on medical images, such as CT (computerized tomography) and MR (magnetic resonance) images. However, little is known about how biomechanics governs the biological nature for femoral tunnel position. In the present study, three volunteers' motion trails were captured by six cameras when they were doing squat movement. The medical image can reconstruct the structure of the ligaments and bones and a left knee model was reconstructed by MIMICS by MRI data of DICOM format. Finally, the effects of different femoral tunnel positions on ACL biomechanics were characterized by the inverse dynamic analysis method. The results showed that there were significant differences in the direct mechanical effects of the anterior cruciate ligament at different locations of the femoral tunnel (p < 0.05), the peak stress of ACL in the low tension area was 1097.24 ± 25.55 N, and the peak stress of ACL in the distal femur was 356.81 ± 15.39 N, both of which were much higher than that in the direct fiber area (118.78 ± 20.68 N).
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Affiliation(s)
- Yadong Chen
- School of Electrical Engineering, Shenyang University of Technology, Shenyang, China
| | - Tianxing Gong
- School of Electrical Engineering, Shenyang University of Technology, Shenyang, China
| | - Nan Jiang
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, China
| | - Aoxiang Zhao
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, China
| | - Tongyu Wang
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, China
| | - Xiangdong Wang
- Sports Science Research Institute of the State Sports General Administration, China Institute of Sport Science, Beijing, China
| | - Wenfeng Han
- Sports Science Research Institute of the State Sports General Administration, General Hospital of northern theater command, Shenyang, China
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5
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Gögele C, Hahn J, Schulze-Tanzil G. Anatomical Tissue Engineering of the Anterior Cruciate Ligament Entheses. Int J Mol Sci 2023; 24:ijms24119745. [PMID: 37298698 DOI: 10.3390/ijms24119745] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/23/2023] [Accepted: 05/26/2023] [Indexed: 06/12/2023] Open
Abstract
The firm integration of anterior cruciate ligament (ACL) grafts into bones remains the most demanding challenge in ACL reconstruction, since graft loosening means graft failure. For a functional-tissue-engineered ACL substitute to be realized in future, robust bone attachment sites (entheses) have to be re-established. The latter comprise four tissue compartments (ligament, non-calcified and calcified fibrocartilage, separated by the tidemark, bone) forming a histological and biomechanical gradient at the attachment interface between the ACL and bone. The ACL enthesis is surrounded by the synovium and exposed to the intra-articular micromilieu. This review will picture and explain the peculiarities of these synovioentheseal complexes at the femoral and tibial attachment sites based on published data. Using this, emerging tissue engineering (TE) strategies addressing them will be discussed. Several material composites (e.g., polycaprolactone and silk fibroin) and manufacturing techniques (e.g., three-dimensional-/bio-printing, electrospinning, braiding and embroidering) have been applied to create zonal cell carriers (bi- or triphasic scaffolds) mimicking the ACL enthesis tissue gradients with appropriate topological parameters for zones. Functionalized or bioactive materials (e.g., collagen, tricalcium phosphate, hydroxyapatite and bioactive glass (BG)) or growth factors (e.g., bone morphogenetic proteins [BMP]-2) have been integrated to achieve the zone-dependent differentiation of precursor cells. However, the ACL entheses comprise individual (loading history) asymmetric and polar histoarchitectures. They result from the unique biomechanical microenvironment of overlapping tensile, compressive and shear forces involved in enthesis formation, maturation and maintenance. This review should provide a road map of key parameters to be considered in future in ACL interface TE approaches.
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Affiliation(s)
- Clemens Gögele
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Nuremberg and Salzburg, Prof. Ernst Nathan Str. 1, 90419 Nuremberg, Germany
| | - Judith Hahn
- Workgroup BioEngineering, Department Materials Engineering, Institute of Polymers Materials, Leibniz-Institut für Polymerforschung Dresden e.V. (IPF), Hohe Straße 6, 01069 Dresden, Germany
| | - Gundula Schulze-Tanzil
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Nuremberg and Salzburg, Prof. Ernst Nathan Str. 1, 90419 Nuremberg, Germany
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6
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Pauly H, Fischenich K, Kelly D, Popat K, Easley J, Palmer RH, Haut Donahue TL. The Effect of Anterior Cruciate Ligament Reconstruction with an Electropsun Scaffold on Tibiofemoral Contact Mechanics. Ann Biomed Eng 2021; 49:3748-3759. [PMID: 34668099 DOI: 10.1007/s10439-021-02874-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 09/29/2021] [Indexed: 11/28/2022]
Abstract
Surgical reconstruction of the torn ACL is performed to restore native contact mechanics. Drawbacks to traditional ACL repair techniques motivate the development of a tissue engineered ACL scaffold. Our group has developed a hierarchical electrospun polycaprolactone (PCL) scaffold that consists of rolled nanofiber bundles attached at each end with solvent-case blocks of PCL. The goal of this study was to compare ovine cadaver tibiofemoral contact mechanics after ACL reconstruction with the electrospun scaffold to a clinically applicable ACL reconstruction with a soft tissue graft and the ACL transected condition (ACLX). In the ACLX group and after ACL reconstruction with either the electrospun scaffold or soft tissue graft, pressure sensors were inserted under the menisci. Loads up to 890 N were applied at various flexion angles. The scaffold performed the best at restoring contact mechanics in the medial hemijoint to that of the native ACL. The scaffold was good at maintaining a medial-lateral balance of pressures as in the native joint whereas the ACLX shifted pressure off the lateral and on to the medial hemijoint. While the ACL scaffold didn't restore mechanics to that of the native condition, it improved contact mechanics compared to the standard graft replacement and ACLX condition.
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Affiliation(s)
- Hannah Pauly
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO, USA
| | - Kristine Fischenich
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO, USA.,Department of Mechanical Engineering, Colorado State University, Fort Collins, CO, USA
| | - Daniel Kelly
- Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Ketul Popat
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO, USA.,Department of Mechanical Engineering, Colorado State University, Fort Collins, CO, USA
| | - Jeremiah Easley
- Clinical Sciences Department, Colorado State University, Fort Collins, CO, USA
| | - Ross H Palmer
- Clinical Sciences Department, Colorado State University, Fort Collins, CO, USA
| | - Tammy L Haut Donahue
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO, USA. .,Department of Mechanical Engineering, Colorado State University, Fort Collins, CO, USA. .,Department of Biomedical Engineering, University of Memphis, 330 Engineering Technology, Memphis, TN, 38114, USA.
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7
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Lui H, Vaquette C, Denbeigh JM, Bindra R, Kakar S, van Wijnen AJ. Multiphasic scaffold for scapholunate interosseous ligament reconstruction: A study in the rabbit knee. J Orthop Res 2021; 39:1811-1824. [PMID: 32579261 PMCID: PMC7758190 DOI: 10.1002/jor.24785] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 06/06/2020] [Accepted: 06/12/2020] [Indexed: 02/04/2023]
Abstract
Scapholunate interosseous ligament tears are a common wrist injury in young and active patients that can lead to suboptimal outcomes after repair. This research aims to assess a multiphasic scaffold using 3D-printing for reconstruction of the dorsal scapholunate interosseous ligament. The scaffold was surgically implanted in vivo in the position of the native rabbit medial collateral ligament. Two branches of treatment were implemented in the study. In the first group, the rabbits (n = 8) had the knee joint fixed in flexion for 4 weeks using 1.4 mm K-wires prior to sample harvesting. The second group (n = 8) had the rabbit knee joint immobilized for 4 weeks prior to K-wire removal and mobilization for an additional 4 weeks prior to sample harvesting. Overall, samples were harvested at 4 weeks post-surgery (immobilized group) and eight weeks post-surgery (mobilized group). Mechanical tensile testing (n = 5/group) and histology (n = 3/group) of the constructs were conducted. Tissue integration and maturation were observed resulting in increased mechanical strength of the operated joint at 8 weeks (P < .05). Bone and ligament tissues were regenerated in their respective compartments with structural and mechanical properties approaching those reported for the human dorsal SLIL ligament. Clinical Significance: This proof of concept study has demonstrated that the synthetic multiphasic scaffold was capable of regenerating both bone and ligament while also withstanding the physiological load once implanted in the rabbit knee. The artificial scaffold may provide an alternative to current techniques for reconstruction of scapholunate instability or other ligament injuries in the hand and wrist.
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Affiliation(s)
- Hayman Lui
- Griffith University, School of Medicine, Gold Coast, Queensland, Australia
| | - Cedryck Vaquette
- The University of Queensland, School of Dentistry, Brisbane, Queensland, Australia
| | - Janet M. Denbeigh
- Mayo Clinic, Department of Orthopedic Surgery, Rochester, Minnesota, United States of America
| | - Randip Bindra
- Griffith University, School of Medicine, Gold Coast, Queensland, Australia,Gold Coast University Hospital, Department of Orthopaedic Surgery, Gold Coast, Queensland, Australia
| | - Sanjeev Kakar
- Mayo Clinic, Department of Orthopedic Surgery, Rochester, Minnesota, United States of America,Corresponding AuthorsProf Andre van Wijnen, Department of Orthopedic Surgery and Biochemistry & Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA, +1-507-293-2105, , Dr Sanjeev Kakar, Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA,
| | - Andre J. van Wijnen
- Mayo Clinic, Department of Orthopedic Surgery, Rochester, Minnesota, United States of America,Corresponding AuthorsProf Andre van Wijnen, Department of Orthopedic Surgery and Biochemistry & Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA, +1-507-293-2105, , Dr Sanjeev Kakar, Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA,
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8
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Wang D, Zhang X, Huang S, Liu Y, Fu BSC, Mak KKL, Blocki AM, Yung PSH, Tuan RS, Ker DFE. Engineering multi-tissue units for regenerative Medicine: Bone-tendon-muscle units of the rotator cuff. Biomaterials 2021; 272:120789. [PMID: 33845368 DOI: 10.1016/j.biomaterials.2021.120789] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 03/25/2021] [Accepted: 03/26/2021] [Indexed: 12/13/2022]
Abstract
Our body systems are comprised of numerous multi-tissue units. For the musculoskeletal system, one of the predominant functional units is comprised of bone, tendon/ligament, and muscle tissues working in tandem to facilitate locomotion. To successfully treat musculoskeletal injuries and diseases, critical consideration and thoughtful integration of clinical, biological, and engineering aspects are necessary to achieve translational bench-to-bedside research. In particular, identifying ideal biomaterial design specifications, understanding prior and recent tissue engineering advances, and judicious application of biomaterial and fabrication technologies will be crucial for addressing current clinical challenges in engineering multi-tissue units. Using rotator cuff tears as an example, insights relevant for engineering a bone-tendon-muscle multi-tissue unit are presented. This review highlights the tissue engineering strategies for musculoskeletal repair and regeneration with implications for other bone-tendon-muscle units, their derivatives, and analogous non-musculoskeletal tissue structures.
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Affiliation(s)
- Dan Wang
- Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong SAR; School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong SAR; Ministry of Education Key Laboratory for Regenerative Medicine, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong SAR; Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR
| | - Xu Zhang
- Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong SAR; School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong SAR
| | - Shuting Huang
- Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong SAR; School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong SAR
| | - Yang Liu
- Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR
| | - Bruma Sai-Chuen Fu
- Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong SAR; Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR
| | | | - Anna Maria Blocki
- Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong SAR; School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong SAR; Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR
| | - Patrick Shu-Hang Yung
- Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong SAR; Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR
| | - Rocky S Tuan
- Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong SAR; School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong SAR
| | - Dai Fei Elmer Ker
- Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong SAR; School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong SAR; Ministry of Education Key Laboratory for Regenerative Medicine, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong SAR; Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR.
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9
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Abstract
Tissue engineering refers to the attempt to create functional human tissue from cells in a laboratory. This is a field that uses living cells, biocompatible materials, suitable biochemical and physical factors, and their combinations to create tissue-like structures. To date, no tissue engineered skeletal muscle implants have been developed for clinical use, but they may represent a valid alternative for the treatment of volumetric muscle loss in the near future. Herein, we reviewed the literature and showed different techniques to produce synthetic tissues with the same architectural, structural and functional properties as native tissues.
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Dyment NA, Barrett JG, Awad H, Bautista CA, Banes A, Butler DL. A brief history of tendon and ligament bioreactors: Impact and future prospects. J Orthop Res 2020; 38:2318-2330. [PMID: 32579266 PMCID: PMC7722018 DOI: 10.1002/jor.24784] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/28/2020] [Accepted: 06/12/2020] [Indexed: 02/04/2023]
Abstract
Bioreactors are powerful tools with the potential to model tissue development and disease in vitro. For nearly four decades, bioreactors have been used to create tendon and ligament tissue-engineered constructs in order to define basic mechanisms of cell function, extracellular matrix deposition, tissue organization, injury, and tissue remodeling. This review provides a historical perspective of tendon and ligament bioreactors and their contributions to this advancing field. First, we demonstrate the need for bioreactors to improve understanding of tendon and ligament function and dysfunction. Next, we detail the history and evolution of bioreactor development and design from simple stretching of explants to fabrication and stimulation of two- and three-dimensional constructs. Then, we demonstrate how research using tendon and ligament bioreactors has led to pivotal basic science and tissue-engineering discoveries. Finally, we provide guidance for new basic, applied, and clinical research utilizing these valuable systems, recognizing that fundamental knowledge of cell-cell and cell-matrix interactions combined with appropriate mechanical and chemical stimulation of constructs could ultimately lead to functional tendon and ligament repairs in the coming decades.
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Affiliation(s)
- Nathaniel A. Dyment
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA
| | - Jennifer G. Barrett
- Department of Large Animal Clinical Sciences, Marion duPont Scott Equine Medical Center, Virginia Tech, Leesburg, VA
| | - Hani Awad
- Department of Biomedical Engineering, The Center for Musculoskeletal Research, University of Rochester, Rochester, NY 14627
| | | | - Albert Banes
- Flexcell International Corp., 2730 Tucker St., Suite 200, Burlington, 27215, NC
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC
| | - David L. Butler
- Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, 45221
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11
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Synovialization and Revascularization Enhancement in Repaired and Reconstructed ACL: PCL Fat Pad Transfer Technique. Arthrosc Tech 2020; 9:e1559-e1563. [PMID: 33134060 PMCID: PMC7587456 DOI: 10.1016/j.eats.2020.06.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/11/2020] [Indexed: 02/03/2023] Open
Abstract
The rapid development of anterior cruciate ligament (ACL) reconstruction and repair techniques has significantly improved the outcomes of these procedures. However, there is still some place for how to improve surgical techniques to limit the amount of revision surgeries. Over the past decade, biological solutions and methods of ligament remodeling enhancement have been proposed. The use of the native ACL remnants has been the most thoroughly analyzed technique. However, despite its benefits, this technique may not to be sufficient to improve outcomes and may cause some technical difficulties. On the other hand, the posterior cruciate ligament (PCL) fat pad contains an abundant synovial vascular network and is located in close proximity to the ACL, which makes it a potential biological donor place of cells and tissue that could enhance the ligamentization of the repaired or reconstructed ACL. To optimize the use of this donor site, we propose the technique of ACL synovialization and revascularization enhancement with a PCL fat pad transfer.
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12
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Novakova SS, Rodriguez BL, Vega-Soto EE, Nutter GP, Armstrong RE, Macpherson PCD, Larkin LM. Repairing Volumetric Muscle Loss in the Ovine Peroneus Tertius Following a 3-Month Recovery. Tissue Eng Part A 2020; 26:837-851. [PMID: 32013753 DOI: 10.1089/ten.tea.2019.0288] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Much effort has been made to fabricate engineered tissues on a scale that is clinically relevant to humans; however, scale-up remains one of the most significant technological challenges of tissue engineering to date. To address this limitation, our laboratory has developed tissue-engineered skeletal muscle units (SMUs) and engineered neural conduits (ENCs), and modularly scaled them to clinically relevant sizes for the treatment of volumetric muscle loss (VML). The goal of this study was to evaluate the SMUs and ENCs in vitro, and to test the efficacy of our SMUs and ENCs in restoring muscle function in a clinically relevant large animal (sheep) model. The animals received a 30% VML injury to the peroneus tertius muscle and were allowed to recover for 3 months. The animals were divided into three experimental groups: VML injury without a repair (VML only), repair with an SMU (VML+SMU), or repair with an SMU and ENC (VML+SMU+ENC). We evaluated the SMUs before implantation and found that our single scaled-up SMUs were characterized by the presence of contracting myotubes, linearly aligned extracellular matrix proteins, and Pax7+ satellite cells. Three months after implantation, we found that the repair groups (VML+SMU and VML+SMU+ENC) had restored muscle mass and tetanic force production to a level that was statistically indistinguishable from the uninjured contralateral muscle after 3 months in vivo. Furthermore, we demonstrated the ability of our ENCs to effectively bridge the gap between native nerve and the repair site by eliciting a muscle contraction through direct electrical stimulation of the re-routed nerve. Impact statement The fabrication of tissues of clinically relevant sizes is one of the largest obstacles preventing engineered tissues from achieving widespread use in the clinic. This study aimed to combat this limitation by developing a fabrication method to scale-up tissue-engineered skeletal muscle for the treatment of volumetric muscle loss in a large animal (sheep) model and evaluating the efficacy of the tissue-engineered constructs after a 3-month recovery.
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Affiliation(s)
- Stoyna S Novakova
- Department of Molecular and Integrative Physiology and University of Michigan, Ann Arbor, Michigan, USA
| | - Brittany L Rodriguez
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Emmanuel E Vega-Soto
- Department of Molecular and Integrative Physiology and University of Michigan, Ann Arbor, Michigan, USA
| | - Genevieve P Nutter
- Department of Molecular and Integrative Physiology and University of Michigan, Ann Arbor, Michigan, USA
| | - Rachel E Armstrong
- Department of Molecular and Integrative Physiology and University of Michigan, Ann Arbor, Michigan, USA
| | - Peter C D Macpherson
- Department of Molecular and Integrative Physiology and University of Michigan, Ann Arbor, Michigan, USA
| | - Lisa M Larkin
- Department of Molecular and Integrative Physiology and University of Michigan, Ann Arbor, Michigan, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
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13
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Gwiazda M, Kumar S, Świeszkowski W, Ivanovski S, Vaquette C. The effect of melt electrospun writing fiber orientation onto cellular organization and mechanical properties for application in Anterior Cruciate Ligament tissue engineering. J Mech Behav Biomed Mater 2020; 104:103631. [PMID: 32174392 DOI: 10.1016/j.jmbbm.2020.103631] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 12/23/2019] [Accepted: 01/08/2020] [Indexed: 01/13/2023]
Abstract
The effect of melt electrospun writing fiber arrangement on cellular behavior has not yet been thoroughly investigated. Cellular orientation is particularly important in the context of ligament tissue engineering for orthopedic applications whereby a high degree of cell alignment is present in the native tissue. The aim of this study was to investigate the response of human mesenchymal stem cells (hMSC) to three different patterned porous polycaprolactone scaffolds (aligned, crimped and random) fabricated by melt electrospinning writing, resulting in 20 μm diameter electrospun fibers. Cell orientation was investigated over 4 weeks in vitro and it was demonstrated that the aligned pattern was capable of orientating the hMSCs towards the main direction of the fibers and this feature was maintained over the entire culture period whereas the orientation was rapidly lost in the crimped pattern. In order to fabricate a functional scaffold for ligament tissue engineering, the scaffolds were rolled in three bundles, subsequently braided and combined with a bone compartment (consisting of a melt electrospun scaffold seeded with osteogenically induced hMSCs) for the development of a Bone-Ligament-Bone (BLB) construct. The mechanical properties of non-cellularized and cellularized BLB constructs were assessed under both quasi-static and cyclic conditions. This revealed that the in vitro maturation significantly softened the BLB constructs and that the mechanical properties were several fold lower than those of native tissue. The cyclic testing demonstrated that the presence of cell sheets resulted in increased resilience and elasticity, even though the global mechanical properties were decreased for the in vitro matured constructs (regardless of the pattern). In conclusion, we demonstrated that melt electrospinning writing fiber organization can induce spontaneous cell alignment and that large cellularized BLB constructs with complex geometry can achieve mechanical resilience under cyclic stretching.
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Affiliation(s)
- Marcin Gwiazda
- Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw, Poland; Griffith Health Institute, Griffith University, Gold Coast, Australia
| | - Sudheesh Kumar
- Griffith Health Institute, Griffith University, Gold Coast, Australia
| | - Wojciech Świeszkowski
- Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw, Poland
| | - Saso Ivanovski
- The University of Queensland, School of Dentistry, Herston, Queensland, Australia
| | - Cedryck Vaquette
- The University of Queensland, School of Dentistry, Herston, Queensland, Australia.
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14
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Boys AJ, Kunitake JA, Henak CR, Cohen I, Estroff LA, Bonassar LJ. Understanding the Stiff-to-Compliant Transition of the Meniscal Attachments by Spatial Correlation of Composition, Structure, and Mechanics. ACS APPLIED MATERIALS & INTERFACES 2019; 11:26559-26570. [PMID: 31267742 PMCID: PMC6680087 DOI: 10.1021/acsami.9b03595] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Recently, the scientific community has shown considerable interest in engineering tissues with organized compositional and structural gradients to mimic hard-to-soft tissue interfaces. This effort is hindered by an incomplete understanding of the construction of native tissue interfaces. In this work, we combined Raman microscopy and confocal elastography to map compositional, structural, and mechanical features across the stiff-to-compliant interface of the attachments of the meniscus in the knee. This study provides new insight into the methods by which biology mediates multiple orders of magnitude changes in stiffness over tens of microns. We identified how the nano- to mesoscale architecture mediates complex microscale transitional regions across the interface: two regions defined by chemical composition, five distinguished by structural features, and three mechanically distinct regions. We identified three major components that lead to a robust interface between a soft tissue and bone: mobile collagen fiber units, a continuous interfacial region, and a local stiffness gradient. This tissue architecture allows for large displacements of collagen fibers in the attachments, enabling meniscal movement without localizing strains to the soft tissue-to-bone interface. The interplay of these regions reveals a method relying on hierarchical structuring across multiple length scales to minimize stress concentrators between highly dissimilar materials. These insights inspire new design strategies for synthetic soft tissue-to-bone attachments and biomimetic material interfaces.
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Affiliation(s)
- Alexander J. Boys
- Department of Materials Science & Engineering, Cornell University, Ithaca, NY 14853
| | | | - Corinne R. Henak
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853
| | - Itai Cohen
- Department of Physics, Cornell University, Ithaca, NY 14853
| | - Lara A. Estroff
- Department of Materials Science & Engineering, Cornell University, Ithaca, NY 14853
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY 14853
| | - Lawrence J. Bonassar
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853
- Sibley School of Mechanical Engineering, Cornell University, Ithaca, NY 14853
- Corresponding Author:
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15
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Lui H, Bindra R, Baldwin J, Ivanovski S, Vaquette C. Additively Manufactured Multiphasic Bone-Ligament-Bone Scaffold for Scapholunate Interosseous Ligament Reconstruction. Adv Healthc Mater 2019; 8:e1900133. [PMID: 31112356 DOI: 10.1002/adhm.201900133] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 04/20/2019] [Indexed: 02/02/2023]
Abstract
The scapholunate interosseous ligament (SLIL) is a frequently torn wrist ligament, and current surgical options for SLIL tears are suboptimal. This research aims to develop a novel multiphasic bone-ligament-bone scaffold (BLB) with a porous interface using 3D-printing and cell sheet technology for the reconstruction of the dorsal scapholunate interosseous ligament. The BLB comprises two bone compartments bridged by aligned polycaprolactone fibers mimicking the architecture of the native tissue. Mechanical testing of the BLBs shows their ability to withstand physiological forces. Combination of the BLB with human bone marrow mesenchymal stem cell sheet demonstrates that the harvesting did not compromise cell viability, while allowing homogeneous distribution in the ligament compartment. The BLBs are loaded with cell sheets and bone morphogenetic protein-2 in the ligament and bone compartment respectively prior to ectopic implantation into athymic rats. The histology demonstrates rapid tissue infiltration, high vascularization, and more importantly the maintenance of the compartmentalization as bone formation remains localized to the bone compartment despite the porous interface. The cells in the ligament compartment become preferentially aligned, and this proof-of-concept study demonstrates that the BLB can provide sufficient compartmentalization and fiber guiding properties necessary for the regeneration of the dorsal SLIL.
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Affiliation(s)
- Hayman Lui
- School of Medicine, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD, 4215, Australia
| | - Randy Bindra
- School of Medicine, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD, 4215, Australia
| | - Jeremy Baldwin
- Centre in Regenerative Medicine Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, 4059, Australia
| | - Saso Ivanovski
- School of Dentistry, the University of Queensland, Herston, 4006, Queensland, Australia
| | - Cedryck Vaquette
- Centre in Regenerative Medicine Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, 4059, Australia
- School of Dentistry, the University of Queensland, Herston, 4006, Queensland, Australia
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16
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Boys AJ, Zhou H, Harrod JB, McCorry MC, Estroff LA, Bonassar LJ. Top-down Fabrication of Spatially Controlled Mineral-Gradient Scaffolds for Interfacial Tissue Engineering. ACS Biomater Sci Eng 2019; 5:2988-2997. [PMID: 31211246 DOI: 10.1021/acsbiomaterials.9b00176] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Materials engineering can generally be divided into "bottom-up" and "top-down" approaches, where current state-of-the-art methodologies are bottom-up, relying on the advent of atomic-scale technologies. Applying bottom-up approaches to biological tissues is challenging due to the inherent complexity of these systems. Top-down methodologies provide many advantages over bottom-up approaches for biological tissues, given that some of the complexity is already built into the system. Here, we generate interfacial scaffolds by the spatially controlled removal of mineral content from trabecular bone using a chelating solution. We controlled the degree and location of the mineral interface, producing scaffolds that support cell growth, while maintaining the hierarchical structure of these tissues. We characterized the structural and compositional gradients across the scaffold using X-ray diffraction, microcomputed tomography (μCT), and Raman microscopy, revealing the presence of mineral gradients on the scale of 20 - 40 μm. Using these data, we generated a model showing the dependence of mineral removal as function of time in the chelating solution and initial bone morphology, specifically trabecular density. These scaffolds will be useful for interfacial tissue engineering, with application in the fields of orthopedics, developmental biology, and cancer metastasis to bone.
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Affiliation(s)
- Alexander J Boys
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY
| | - Hao Zhou
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY
| | - Jordan B Harrod
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY
| | | | - Lara A Estroff
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY.,Kavli Institute for Nanoscale Science at Cornell, Cornell University, Ithaca, NY
| | - Lawrence J Bonassar
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY.,Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY
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17
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Iannucci LE, Boys AJ, McCorry MC, Estroff LA, Bonassar LJ. Cellular and Chemical Gradients to Engineer the Meniscus-to-Bone Insertion. Adv Healthc Mater 2019; 8:e1800806. [PMID: 30536862 PMCID: PMC6458090 DOI: 10.1002/adhm.201800806] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 09/21/2018] [Indexed: 12/13/2022]
Abstract
Tissue-engineered menisci hold promise as an alternative to allograft procedures but require a means of robust fixation to the native bone. The insertion of the meniscus into bone is critical for meniscal function and inclusion of a soft tissue-to-bone interface in a tissue engineered implant can aid in the fixation process. The native insertion is characterized by gradients in composition, tissue architecture, and cellular phenotype, which are all difficult to replicate. In this study, a soft tissue-to-bone interface is tissue engineered with a cellular gradient of fibrochondrocytes and mesenchymal stem cells and subjected to a biochemical gradient through a custom media diffusion bioreactor. These constructs, consisting of interpenetrating collagen and boney regions, display improved mechanical performance and collagen organization compared to controls without a cellular or chemical gradient. Media gradient exposure produces morphological features in the constructs that appear similar to the native tissue. Collectively, these data show that cellular and biochemical gradients improve integration between collagen and bone in a tissue engineered soft tissue-to-bone construct.
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Affiliation(s)
| | - Alexander J. Boys
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY
| | | | - Lara A. Estroff
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY
| | - Lawrence J. Bonassar
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY
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18
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Pauly H, Kelly D, Popat K, Easley J, Palmer R, Haut Donahue TL. Mechanical properties of a hierarchical electrospun scaffold for ovine anterior cruciate ligament replacement. J Orthop Res 2019; 37:421-430. [PMID: 30474882 DOI: 10.1002/jor.24183] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 10/30/2018] [Indexed: 02/04/2023]
Abstract
The anterior cruciate ligament (ACL) acts to stabilize the knee and prevent excessive motion of the tibia relative to the femur. Tears of the ACL are common and can result in pain and damage to surrounding tissues. Thus a torn ACL is often surgically replaced with an autograft or allograft material. Drawbacks to clinically available ACL grafts motivate the development of a tissue engineered ACL replacement. Our group has previously developed a polycaprolactone electrospun scaffold that mimics the hierarchical structure of the ACL. The goal of this study was to investigate the mechanical properties of the electrospun scaffold as an ACL replacement. Scaffold mechanical properties were assessed prior to implantation via stress relaxation and pull to failure testing. Following in vitro characterization, electrospun scaffolds and soft tissue grafts were implanted into ovine cadaver stifle joints as ACL replacements. Stifle joints with ACL replacements were tested via a simulated anterior drawer test as well as in situ stress relaxation and pull to failure tests and compared to stifle joints with the native ACL intact. Prior to implantation the scaffold matched the native ovine ACL well in the range of functional strains as evidenced by stress relaxation measures and the toe region stiffness. After implantation the scaffold was more similar to the native ACL than the soft tissue graft, particularly when it came to reducing joint laxity and matching stress relaxation measures. These results demonstrate that the electrospun scaffold has the potential to be a suitable material for ACL replacement. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:421-430, 2019.
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Affiliation(s)
- Hannah Pauly
- School of Biomedical Engineering, Colorado State University, Fort Collins, Colorado
| | - Daniel Kelly
- Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland.,Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin, Ireland.,Department of Anatomy, Royal College of Surgeons in Ireland, Dublin 2, Ireland.,Advanced Materials and Bioengineering Research Centre, Royal College of Surgeons in Ireland and Trinity College Dublin, Dublin, Ireland
| | - Ketul Popat
- School of Biomedical Engineering, Colorado State University, Fort Collins, Colorado.,Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado
| | - Jeremiah Easley
- Clinical Sciences Department, Colorado State University, Fort Collins, Colorado
| | - Ross Palmer
- Clinical Sciences Department, Colorado State University, Fort Collins, Colorado
| | - Tammy L Haut Donahue
- School of Biomedical Engineering, Colorado State University, Fort Collins, Colorado.,Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado.,Department of Biomedical Engineering, University of Massachusetts, 130 Natural Resources Rd., Amherst, Massachusetts 01003
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19
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Laurent C, Liu X, De Isla N, Wang X, Rahouadj R. Defining a scaffold for ligament tissue engineering: What has been done, and what still needs to be done. ACTA ACUST UNITED AC 2018. [DOI: 10.1016/j.jocit.2018.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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20
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Lee KI, Lee JS, Kang KT, Shim YB, Kim YS, Jang JW, Moon SH, D'Lima DD. In Vitro and In Vivo Performance of Tissue-Engineered Tendons for Anterior Cruciate Ligament Reconstruction. Am J Sports Med 2018; 46:1641-1649. [PMID: 29578751 DOI: 10.1177/0363546518759729] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Anterior cruciate ligament (ACL) reconstruction is the current standard of care for ACL tears. However, the results are not consistently successful; autografts or allografts have certain disadvantages; and synthetic grafts have had poor clinical results. PURPOSE To determine if recellularization of decellularized tendons combined with mechanical stimulation in a bioreactor could replicate the mechanical properties of the native ACL and be successfully used for ACL reconstruction in vivo. STUDY DESIGN Controlled laboratory study. METHODS Porcine tibialis tendons were decellularized and then recellularized with human adult bone marrow-derived stem cells. Tendons were cultured in a tissue bioreactor that provided biaxial cyclic loading for up to 7 days. To reproduce mechanical stresses similar to those experienced by the ACL within the knee joint, the tendons were subjected to simultaneous tension and torsion in the bioreactor. Expression of tendon-specific genes and newly synthesized collagen and glycosaminoglycan were used to quantify the efficacy of recellularization and dynamic bioreactor culture. The ultimate tensile load to failure and stiffness of recellularized constructs were measured after dynamic stimulation. Finally, the tissue-engineered tendons were used to reconstruct the ACL in 24 pigs, and ultimate tensile load to failure and stiffness were assessed after 3 months. RESULTS Dynamic bioreactor culture significantly increased the expression of tendon-specific genes, the quantity of newly synthesized collagen and glycosaminoglycan, and the ultimate tensile load and stiffness of recellularized tendons. After in vivo reconstruction, the ultimate tensile load and stiffness of the tissue-engineered tendons increased significantly up to 3 months after surgery and were within 80% of the ultimate tensile load of the natural ACL. CONCLUSION This translational study indicates that recellularization and dynamic mechanical stimuli can significantly enhance matrix synthesis and ultimate tensile load of decellularized porcine tibialis tendons. This approach to tissue engineering can be very useful for ACL reconstruction and may overcome some of the disadvantages of autografts and allografts. CLINICAL RELEVANCE Dynamic bioreactor cultivation of tissue-engineered tendons may overcome the limitations of autografts and allografts.
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Affiliation(s)
- Kwang Il Lee
- The Institute of Biomaterial and Medical Engineering, Cellumed Co, Ltd, Seoul, Republic of Korea
| | - Jung Soo Lee
- The Institute of Biomaterial and Medical Engineering, Cellumed Co, Ltd, Seoul, Republic of Korea
| | - Kyoung Tak Kang
- Department of Mechanical Engineering, College of Engineering, Yonsei University, Seoul, Republic of Korea
| | - Young Bock Shim
- The Institute of Biomaterial and Medical Engineering, Cellumed Co, Ltd, Seoul, Republic of Korea
| | - Young Sik Kim
- The Institute of Biomaterial and Medical Engineering, Cellumed Co, Ltd, Seoul, Republic of Korea
| | - Ju Woong Jang
- The Institute of Biomaterial and Medical Engineering, Cellumed Co, Ltd, Seoul, Republic of Korea
| | - Seong Hwan Moon
- Department of Orthopaedic Surgery, College of Medicine, Yonsei University, Seoul, Republic of Korea
| | - Darryl D D'Lima
- Shiley Center for Orthopaedic Research and Education at Scripps Clinic, La Jolla, California, USA
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21
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Syverud BC, Gumucio JP, Rodriguez BL, Wroblewski OM, Florida SE, Mendias CL, Larkin LM. A Transgenic tdTomato Rat for Cell Migration and Tissue Engineering Applications. Tissue Eng Part C Methods 2018; 24:263-271. [PMID: 29490563 DOI: 10.1089/ten.tec.2017.0406] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The growing deficit in suitable tissues for patients awaiting organ transplants demonstrates the clinical need for engineered tissues as alternative graft sources. Demonstrating safety and efficacy by tracking the migration and fate of implanted cells is a key consideration required for approval of promising engineered tissues. Cells from transgenic animals that express green fluorescent protein (GFP) are commonly used for this purpose. However, GFP can create difficulties in practice due to high levels of green autofluorescence in many musculoskeletal tissues. Tandem-dimer tomato (tdTomato) is a stable, robust red fluorescent protein that is nearly threefold brighter than GFP. Our objective was to create a line of transgenic rats that ubiquitously express tdTomato in all cells, driven by the human ubiquitin C promoter. We sought to determine the rats' utility in tissue engineering applications by fabricating engineered skeletal muscle units (SMUs) from isolated muscle-derived tdTomato cells. These tdTomato SMUs were implanted into a volumetric muscle loss (VML) defect of the tibialis anterior muscle in a rat ubiquitously expressing GFP. We also evaluated a novel method for modularly combining individual SMUs to create a larger engineered tissue. Following a recovery period of 28 days, we found that implantation of the modular SMU led to a significant decrease in the size of the remaining VML deficit. Histological analysis of explanted tissues demonstrated both tdTomato and GFP expression in the repair site, indicating involvement of both implanted and host cells in the regeneration process. These results demonstrate the successful generation of a tdTomato transgenic rat, and the use of these rats in tissue engineering and cell migration applications. Furthermore, this study successfully validated a method for scaling engineered tissues to larger sizes, a factor that will be important for repairing volumetric injuries in more clinically relevant models.
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Affiliation(s)
- Brian C Syverud
- 1 Department of Biomedical Engineering, University of Michigan , Ann Arbor, Michigan
| | - Jonathan P Gumucio
- 2 Department of Molecular and Integrative Physiology, University of Michigan , Ann Arbor, Michigan.,3 Department of Orthopedic Surgery, University of Michigan , Ann Arbor, Michigan
| | - Brittany L Rodriguez
- 1 Department of Biomedical Engineering, University of Michigan , Ann Arbor, Michigan
| | - Olga M Wroblewski
- 1 Department of Biomedical Engineering, University of Michigan , Ann Arbor, Michigan
| | - Shelby E Florida
- 2 Department of Molecular and Integrative Physiology, University of Michigan , Ann Arbor, Michigan
| | - Christopher L Mendias
- 2 Department of Molecular and Integrative Physiology, University of Michigan , Ann Arbor, Michigan.,3 Department of Orthopedic Surgery, University of Michigan , Ann Arbor, Michigan
| | - Lisa M Larkin
- 1 Department of Biomedical Engineering, University of Michigan , Ann Arbor, Michigan.,2 Department of Molecular and Integrative Physiology, University of Michigan , Ann Arbor, Michigan
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22
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Assessment of static and perfusion methods for decellularization of PCL membrane-supported periodontal ligament cell sheet constructs. Arch Oral Biol 2018; 88:67-76. [DOI: 10.1016/j.archoralbio.2018.01.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 12/27/2017] [Accepted: 01/18/2018] [Indexed: 11/21/2022]
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23
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Patel S, Caldwell JM, Doty SB, Levine WN, Rodeo S, Soslowsky LJ, Thomopoulos S, Lu HH. Integrating soft and hard tissues via interface tissue engineering. J Orthop Res 2018; 36:1069-1077. [PMID: 29149506 PMCID: PMC6467291 DOI: 10.1002/jor.23810] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 10/21/2017] [Indexed: 02/04/2023]
Abstract
The enthesis, or interface between bone and soft tissues such as ligament and tendon, is prone to injury and often does not heal, even post surgical intervention. Interface tissue engineering represents an integrative strategy for regenerating the native enthesis by functionally connecting soft and hard tissues and thereby improving clinical outcome. This review focuses on integrative and cell-instructive scaffold designs that target the healing of the two most commonly injured soft tissue-bone junctions: tendon-bone interface (e.g., rotator cuff) and ligament-bone interface (e.g., anterior cruciate ligament). The inherent connectivity between soft and hard tissues is instrumental for musculoskeletal motion and is therefore a key design criterion for soft tissue regeneration. To this end, scaffold design for soft tissue regeneration have progressed from single tissue systems to the emerging focus on pre-integrated and functional composite tissue units. Specifically, a multifaceted, bioinspired approach has been pursued wherein scaffolds are tailored to stimulate relevant cell responses using spatially patterned structural and chemical cues, growth factors, and/or mechanical stimulation. Moreover, current efforts to elucidate the essential scaffold design criteria via strategic biomimicry are emphasized as these will reduce complexity in composite tissue regeneration and ease the related burden for clinical translation. These innovative studies underscore the clinical relevance of engineering connective tissue integration and have broader impact in the formation of complex tissues and total joint regeneration. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1069-1077, 2018.
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Affiliation(s)
- Sahishnu Patel
- Biomaterials and Interface Tissue Engineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, New York 10027
| | - Jon-Michael Caldwell
- Department of Orthopedic Surgery, New York Presbyterian/Columbia University Medical Center, New York, New York 10032
| | - Stephen B. Doty
- Analytical Microscopy Core Laboratory, Hospital for Special Surgery, New York, New York 10021
| | - William N. Levine
- Department of Orthopedic Surgery, New York Presbyterian/Columbia University Medical Center, New York, New York 10032
| | - Scott Rodeo
- Soft Tissue Research Laboratory, Hospital for Special Surgery, New York, New York 10021
| | - Louis J. Soslowsky
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Stavros Thomopoulos
- Carroll Laboratories of Orthopedic Research, Department of Orthopedic Surgery, Columbia University, New York, New York 10032
| | - Helen H. Lu
- Biomaterials and Interface Tissue Engineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, New York 10027
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24
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Lee-Barthel A, Lee CA, Vidal MA, Baar K. Localized BMP-4 release improves the enthesis of engineered bone-to-bone ligaments. TRANSLATIONAL SPORTS MEDICINE 2018. [DOI: 10.1002/tsm2.9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- A. Lee-Barthel
- Department of Biomedical Engineering; University of California Davis; Davis CA USA
| | - C. A. Lee
- Department of Orthopaedic Surgery; University of California Davis; Sacramento CA USA
| | - M. A. Vidal
- Department of Surgical and Radiological Sciences; University of California Davis; Davis CA USA
| | - K. Baar
- Department of Neurobiology, Physiology, and Behavior; University of California Davis; Davis CA USA
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25
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Novakova SS, Mahalingam VD, Florida SE, Mendias CL, Allen A, Arruda EM, Bedi A, Larkin LM. Tissue-engineered tendon constructs for rotator cuff repair in sheep. J Orthop Res 2018; 36:289-299. [PMID: 28657154 DOI: 10.1002/jor.23642] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 06/25/2017] [Indexed: 02/04/2023]
Abstract
Current rotator cuff repair commonly involves the use of single or double row suture techniques, and despite successful outcomes, failure rates continue to range from 20 to 95%. Failure to regenerate native biomechanical properties at the enthesis is thought to contribute to failure rates. Thus, the need for technologies that improve structural healing of the enthesis after rotator cuff repair is imperative. To address this issue, our lab has previously demonstrated enthesis regeneration using a tissue-engineered graft approach in a sheep anterior cruciate ligament (ACL) repair model. We hypothesized that our tissue-engineered graft designed for ACL repair also will be effective in rotator cuff repair. The goal of this study was to test the efficacy of our Engineered Tissue Graft for Rotator Cuff (ETG-RC) in a rotator cuff tear model in sheep and compare this novel graft technology to the commonly used double row suture repair technique. Following a 6-month recovery, the grafted and contralateral shoulders were removed, imaged using X-ray, and tested biomechanically. Additionally, the infraspinatus muscle, myotendinous junction, enthesis, and humeral head were preserved for histological analysis of muscle, tendon, and enthesis structure. Our results showed that our ETC-RCs reached 31% of the native tendon tangent modulus, which was a modest, non-significant, 11% increase over that of the suture-only repairs. However, the histological analysis showed the regeneration of a native-like enthesis in the ETG-RC-repaired animals. This advanced structural healing may improve over longer times and may diminish recurrence rates of rotator cuff tears and lead to better clinical outcomes. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:289-299, 2018.
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Affiliation(s)
- Stoyna S Novakova
- Departments of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109-2200Michigan 48109-2200
| | - Vasudevan D Mahalingam
- Departments of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109-2200Michigan 48109-2200
| | - Shelby E Florida
- Departments of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109-2200Michigan 48109-2200
| | - Christopher L Mendias
- Departments of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109-2200Michigan 48109-2200.,Departments of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan 48109-2200
| | | | - Ellen M Arruda
- Departments of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2200.,Departments of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2200.,Departments of Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2200
| | - Asheesh Bedi
- Departments of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan 48109-2200
| | - Lisa M Larkin
- Departments of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109-2200Michigan 48109-2200.,Departments of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2200
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26
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Perrone GS, Proffen BL, Kiapour AM, Sieker JT, Fleming BC, Murray MM. Bench-to-bedside: Bridge-enhanced anterior cruciate ligament repair. J Orthop Res 2017; 35:2606-2612. [PMID: 28608618 PMCID: PMC5729057 DOI: 10.1002/jor.23632] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Accepted: 06/05/2017] [Indexed: 02/04/2023]
Abstract
Anterior cruciate ligament (ACL) injuries are one of the most well-known orthopaedic injuries and are treated with one of the most common orthopaedic procedures performed in the United States. This surgical procedure, ACL reconstruction, is successful at restoring the gross stability of the knee. However, the outcomes of ACL reconstruction can be limited by short and long-term complications, including muscle weakness, graft rupture, and premature osteoarthritis. Thus, new methods of treating this injury are being explored. This review details the pathway of how a tissue engineering strategy can be used to improve the healing of the ACL in preclinical studies and then translated to patients in an FDA-approved clinical study. This review paper will outline the clinical importance of ACL injuries, history of primary repair, the pathology behind failure of the ACL to heal, pre-clinical studies, the FDA approval process for a high risk medical device, and the preliminary results from a first-in-human study. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2606-2612, 2017.
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Affiliation(s)
- Gabriel S Perrone
- Department of Orthopaedic Surgery, Sports Medicine Research Laboratory, Harvard Medical School/Boston Children's Hospital, Boston, Massachusetts
| | - Benedikt L Proffen
- Department of Orthopaedic Surgery, Sports Medicine Research Laboratory, Harvard Medical School/Boston Children's Hospital, Boston, Massachusetts
| | - Ata M Kiapour
- Department of Orthopaedic Surgery, Sports Medicine Research Laboratory, Harvard Medical School/Boston Children's Hospital, Boston, Massachusetts
| | - Jakob T Sieker
- Department of Orthopaedic Surgery, Sports Medicine Research Laboratory, Harvard Medical School/Boston Children's Hospital, Boston, Massachusetts
| | - Braden C Fleming
- Department of Orthopaedics, Bioengineering Labs, Warren Alpert Medical School of Brown University/Rhode Island Hospital, Providence, Rhode Island
| | - Martha M Murray
- Department of Orthopaedic Surgery, Sports Medicine Research Laboratory, Harvard Medical School/Boston Children's Hospital, Boston, Massachusetts
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27
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Boys AJ, McCorry MC, Rodeo S, Bonassar LJ, Estroff LA. Next Generation Tissue Engineering of Orthopedic Soft Tissue-to-Bone Interfaces. MRS COMMUNICATIONS 2017; 7:289-308. [PMID: 29333332 PMCID: PMC5761353 DOI: 10.1557/mrc.2017.91] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 08/28/2017] [Indexed: 05/17/2023]
Abstract
Soft tissue-to-bone interfaces are complex structures that consist of gradients of extracellular matrix materials, cell phenotypes, and biochemical signals. These interfaces, called entheses for ligaments, tendons, and the meniscus, are crucial to joint function, transferring mechanical loads and stabilizing orthopedic joints. When injuries occur to connected soft tissue, the enthesis must be re-established to restore function, but due to structural complexity, repair has proven challenging. Tissue engineering offers a promising solution for regenerating these tissues. This prospective review discusses methodologies for tissue engineering the enthesis, outlined in three key design inputs: materials processing methods, cellular contributions, and biochemical factors.
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Affiliation(s)
- Alexander J Boys
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY
| | | | - Scott Rodeo
- Orthopedic Surgery, Hospital for Special Surgery, New York, NY
- Sports Medicine and Shoulder Service, Hospital for Special Surgery, New York, NY
- Tissue Engineering, Regeneration, and Repair Program, Hospital for Special Surgery, New York, NY
- Orthopedic Surgery, Weill Medical College of Cornell University, Cornell University, New York, NY
- New York Giants, East Rutherford, NJ
- Department of Orthopedic Surgery, Hospital for Special Surgery, New York, NY
| | - Lawrence J Bonassar
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY
| | - Lara A Estroff
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY
- Kavli Institute at Cornell, Cornell University, Ithaca, NY
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28
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McCorry MC, Mansfield MM, Sha X, Coppola DJ, Lee JW, Bonassar LJ. A model system for developing a tissue engineered meniscal enthesis. Acta Biomater 2017; 56:110-117. [PMID: 27989921 PMCID: PMC7326006 DOI: 10.1016/j.actbio.2016.10.040] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 10/26/2016] [Accepted: 10/26/2016] [Indexed: 02/07/2023]
Abstract
The meniscus acts as a stabilizer, lubricator, and load distributer in the knee joint. The mechanical stability of the meniscus depends on its connection to the underlying bone by a fibrocartilage to bone transition zone called the meniscal enthesis. Tissue engineered menisci hold great promise as a treatment alternative however lack a means of integrated fixation to the underlying bone needed in order for a tissue engineered meniscal replacement to be successful. Tissue engineering the meniscal enthesis is a difficult task given the complex gradients of cell type, mineral, and extracellular matrix molecules. Therefore, there is a need for a simplified and high throughput enthesis model to test experimental parameters. The goal of this study was to develop a simplified enthesis model to test collagen integration with decellularized bone. We found that injection molding collagen into tubing loaded with decellularized bone plugs resulted in a scaffold with three regions: bone, bone-collagen, and collagen. Furthermore, collagen formation was directed in the axial direction by using mechanical fixation at the bony ends. The results of this study showed that this technique can be used to mimic the native enthesis morphology and serves as ideal test platform to generate a model tissue engineered enthesis. STATEMENT OF SIGNIFICANCE The meniscal enthesis is a complex structure that is essential to mechanical stability of the meniscus and the knee joint. Several studies document the development of anatomically shaped tissue engineered meniscus constructs, but none have focused on how to integrate such tissues with underlying bone. This study establishes a simplified construct to model the meniscal enthesis composed of a collagen gel seeded with meniscal fibrochondrocytes integrated with decellularized cancellous bone. Mechanical fixation at the bony ends induced tissue integration of fibers into the bony tissue, which is critical for mechanical performance and has yet to be shown in enthesis literature. Our test platform is amenable to targeted experiments investigating mineralization gradients, collagen fiber alignment, cell population phenotype, and media conditioning with experimental impact on enthesis studies for meniscus, tendon, and ligament.
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Affiliation(s)
- Mary Clare McCorry
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States.
| | - Melissa M Mansfield
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States.
| | - Xiaozhou Sha
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States.
| | - Daniel J Coppola
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States.
| | - Jonathan W Lee
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States.
| | - Lawrence J Bonassar
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States; Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, United States.
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29
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Lee-Barthel A, Baar K, West DWD. Treatment of Ligament Constructs with Exercise-conditioned Serum: A Translational Tissue Engineering Model. J Vis Exp 2017. [PMID: 28654031 PMCID: PMC5608388 DOI: 10.3791/55339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In vitro experiments are essential to understand biological mechanisms; however, the gap between monolayer tissue culture and human physiology is large, and translation of findings is often poor. Thus, there is ample opportunity for alternative experimental approaches. Here we present an approach in which human cells are isolated from human anterior cruciate ligament tissue remnants, expanded in culture, and used to form engineered ligaments. Exercise alters the biochemical milieu in the blood such that the function of many tissues, organs and bodily processes are improved. In this experiment, ligament construct culture media was supplemented with experimental human serum that has been 'conditioned' by exercise. Thus the intervention is more biologically relevant since an experimental tissue is exposed to the full endogenous biochemical milieu, including binding proteins and adjunct compounds that may be altered in tandem with the activity of an unknown agent of interest. After treatment, engineered ligaments can be analyzed for mechanical function, collagen content, morphology, and cellular biochemistry. Overall, there are four major advantages versus traditional monolayer culture and animal models, of the physiological model of ligament tissue that is presented here. First, ligament constructs are three-dimensional, allowing for mechanical properties (i.e., function) such as ultimate tensile stress, maximal tensile load, and modulus, to be quantified. Second, the enthesis, the interface between boney and sinew elements, can be examined in detail and within functional context. Third, preparing media with post-exercise serum allows for the effects of the exercise-induced biochemical milieu, which is responsible for the wide range of health benefits of exercise, to be investigated in an unbiased manner. Finally, this experimental model advances scientific research in a humane and ethical manner by replacing the use of animals, a core mandate of the National Institutes of Health, the Center for Disease Control, and the Food and Drug Administration.
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Affiliation(s)
- Ann Lee-Barthel
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis
| | - Keith Baar
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis; Department of Physiology and Membrane Biology, University of California, Davis;
| | - Daniel W D West
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis; Faculty of Kinesiology and Physical Education, University of Toronto
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30
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Smietana MJ, Moncada-Larrotiz P, Arruda EM, Bedi A, Larkin LM. Tissue-Engineered Tendon for Enthesis Regeneration in a Rat Rotator Cuff Model. Biores Open Access 2017; 6:47-57. [PMID: 28736687 PMCID: PMC5515124 DOI: 10.1089/biores.2016.0042] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Healing of rotator cuff (RC) injuries with current suture or augmented scaffold techniques fails to regenerate the enthesis and instead forms a weaker fibrovascular scar that is prone to subsequent failure. Regeneration of the enthesis is the key to improving clinical outcomes for RC injuries. We hypothesized that the utilization of our tissue-engineered tendon to repair either an acute or a chronic full-thickness supraspinatus tear would regenerate a functional enthesis and return the biomechanics of the tendon back to that found in native tissue. Engineered tendons were fabricated from bone marrow-derived mesenchymal stem cells utilizing our well-described fabrication technology. Forty-three rats underwent unilateral detachment of the supraspinatus tendon followed by acute (immediate) or chronic (4 weeks retracted) repair by using either our engineered tendon or a trans-osseous suture technique. Animals were sacrificed at 8 weeks. Biomechanical and histological analyses of the regenerated enthesis and tendon were performed. Statistical analysis was performed by using a one-way analysis of variance with significance set at p < 0.05. Acute repairs using engineered tendon had improved enthesis structure and lower biomechanical failures compared with suture repairs. Chronic repairs with engineered tendon had a more native-like enthesis with increased fibrocartilage formation, reduced scar formation, and lower biomechanical failure compared with suture repair. Thus, the utilization of our tissue-engineered tendon showed improve enthesis regeneration and improved function in chronic RC repairs compared with suture repair. Clinical Significance: Our engineered tendon construct shows promise as a clinically relevant method for repair of RC injuries.
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Affiliation(s)
- Michael J Smietana
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan
| | - Pablo Moncada-Larrotiz
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Ellen M Arruda
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan.,Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan.,Department of Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan
| | - Asheesh Bedi
- Department of Orthopedic Surgery, University of Michigan, Ann Arbor, Michigan
| | - Lisa M Larkin
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan.,Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan
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31
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Florida SE, VanDusen KW, Mahalingam VD, Schlientz AJ, Wojtys EM, Wellik DM, Larkin LM. In vivo structural and cellular remodeling of engineered bone-ligament-bone constructs used for anterior cruciate ligament reconstruction in sheep. Connect Tissue Res 2016; 57:526-538. [PMID: 27184487 PMCID: PMC5167374 DOI: 10.1080/03008207.2016.1187141] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Anterior cruciate ligament (ACL) ruptures rank among the most prevalent and costly sports-related injuries. Current tendon grafts used for ACL reconstruction are limited by suboptimal biomechanical properties. We have addressed these issues by engineering multiphasic bone-ligament-bone (BLB) constructs that develop structural and mechanical properties similar to native ACL. The purpose of this study was to examine the acute remodeling process that occurs as the BLB grafts advance toward the adult ligament phenotype in vivo. Thus, we implanted BLB constructs fabricated from male cells into female host sheep and allowed 3, 7, 14, or 28 days (n = 4 at each time point) for recovery. To address whether or not graft-derived cells were even necessary, a subset of BLB constructs (n = 3) were acellularized, implanted, and allowed 28 days for recovery. At each recovery time point, the following histological analyses were performed: picrosirius red staining to assess collagen alignment and immunohistochemistry to assess both graft development and host immune response. Polymerase chain reaction (PCR) analysis, performed on every explanted BLB, was used to detect the presence of graft-derived male cells remaining in the constructs and/or migration into surrounding host tissue. The analysis of the PCR and histology samples revealed a rapid migration of host-derived macrophages and neutrophils into the graft at 3 days, followed by increased collagen density and alignment, vascularization, innervation, and near complete repopulation of the graft with host cells within 28 days. This study provides a greater understanding of the processes of ligament regeneration in our BLB constructs as they remodel toward the adult ligament phenotype.
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Affiliation(s)
- Shelby E. Florida
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Keith W. VanDusen
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Vasudevan D. Mahalingam
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Aleesa J. Schlientz
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Edward M. Wojtys
- Medsport Sports Medicine Program, Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Deneen M. Wellik
- Department of Cell & Developmental Biology University of Michigan, Ann Arbor, Michigan, USA,Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Lisa M. Larkin
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA,Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
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32
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Mahalingam V, Wojtys EM, Wellik DM, Arruda EM, Larkin LM. Fresh and Frozen Tissue-Engineered Three-Dimensional Bone-Ligament-Bone Constructs for Sheep Anterior Cruciate Ligament Repair Following a 2-Year Implantation. Biores Open Access 2016; 5:289-298. [PMID: 27843707 PMCID: PMC5107674 DOI: 10.1089/biores.2016.0032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Injuries to the anterior cruciate ligament (ACL) often require surgical reconstruction utilizing tendon grafts to restore knee function and stability. Some current graft options for ACL repair are associated with poor long-term outcomes. Our laboratory has fabricated tissue-engineered bone–ligament–bone (BLB) constructs that demonstrate native ligament regeneration and advancement toward native ACL mechanical properties in a sheep ACL reconstruction model. Prior work has shown that freezing BLBs as a method of preservation resulted in similar outcomes compared with fresh BLBs after 6-month implantation. The purpose of this study was to evaluate the long-term efficacy of fresh and frozen BLBs. We hypothesized that both fresh and frozen BLBs would show continued regeneration of structural and functional properties toward those of native ACL after a 2-year implantation. Following removal of the native ACL, fresh (n = 2) and frozen (n = 2) BLBs were implanted arthroscopically. After 2 years of recovery, sheep were euthanized and both the experimental and contralateral hindlimbs were removed and radiographs were performed. Explanted knees were initially evaluated for joint laxity and were then further dissected for uniaxial tensile testing of the isolated ACL or BLB. Following mechanical testing, explanted contralateral ACL (C-ACL) and BLBs were harvested for histology. Two years post-ACL reconstruction, fresh and frozen BLBs exhibited similar morphological and biomechanical properties as well as more advanced regeneration compared with our 6-month recovery study. These data indicate that an additional 1.5-year regeneration period allows the BLB to continue ligament regeneration in vivo. In addition, freezing the BLBs is a viable option for the preservation of the graft after fabrication.
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Affiliation(s)
- Vasudevan Mahalingam
- Department of Molecular and Integrative Physiology, University of Michigan , Ann Arbor, Michigan
| | - Edward M Wojtys
- Medsport Sports Medicine Program, Department of Orthopaedic Surgery, University of Michigan , Ann Arbor, Michigan
| | - Deneen M Wellik
- Department of Internal Medicine, Division of Molecular Medicine and Genetics, University of Michigan , Ann Arbor, Michigan
| | - Ellen M Arruda
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan.; Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan.; Program in Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan
| | - Lisa M Larkin
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan.; Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan
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33
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Cross LM, Thakur A, Jalili NA, Detamore M, Gaharwar AK. Nanoengineered biomaterials for repair and regeneration of orthopedic tissue interfaces. Acta Biomater 2016; 42:2-17. [PMID: 27326917 DOI: 10.1016/j.actbio.2016.06.023] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 06/07/2016] [Accepted: 06/16/2016] [Indexed: 12/21/2022]
Abstract
UNLABELLED Orthopedic interface tissue engineering aims to mimic the structure and function of soft-to-hard tissue junctions, particularly bone-ligament, bone-tendon, and bone-cartilage interfaces. A range of engineering approaches has been proposed to mimic the gradient architecture, physical properties and chemical characteristics of interface tissues using conventional polymeric biomaterials. Recent developments in nanomaterials and nanofabrication technologies introduce a range of synthesis and fabrication tools to effectively engineer the structure and function of native tissue interfaces. In this review, we will focus on nanoengineered strategies used to replicate the structural and functional aspects of native biological tissues for engineering bone-cartilage, bone-ligament, and bone-tendon interfaces. This review will also highlight some of the emerging applications and future potential of nanomaterials and fabrication technologies in engineering tissue interfaces. STATEMENT OF SIGNIFICANCE A major challenge in engineering interfaces is to control the physical and structural characteristics of an artificial environment. The use of nanomaterials and nanoengineered strategies allow for greater control over the changes in structure and function at molecular and nanometer length scale. This review focuses on advanced nanomaterials and nanofabrication approaches developed to emulate bone-cartilage, bone-ligament, and bone-tendon interface regions. Some of the emerging nanoengineered biomaterials proposed to mimic tissue interfaces are also highlighted.
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Affiliation(s)
- Lauren M Cross
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77841, USA
| | - Ashish Thakur
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77841, USA
| | - Nima A Jalili
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77841, USA
| | - Michael Detamore
- Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, KS 66045, USA
| | - Akhilesh K Gaharwar
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77841, USA; Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77841, USA; Center for Remote Health Technologies and Systems, Texas A&M University, College Station, TX 77843, USA.
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34
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Beaulieu ML, Carey GE, Schlecht SH, Wojtys EM, Ashton-Miller JA. On the heterogeneity of the femoral enthesis of the human ACL: microscopic anatomy and clinical implications. J Exp Orthop 2016; 3:14. [PMID: 27412665 PMCID: PMC4943914 DOI: 10.1186/s40634-016-0050-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 07/07/2016] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Most ruptures of the native anterior cruciate ligament (ACL) and ACL graft occur at, or near, the femoral enthesis, with the posterolateral fibers of the native ligament being especially vulnerable during pivot landings. Characterizing the anatomy of the ACL femoral enthesis may help us explain injury patterns which, in turn, could help guide injury prevention efforts. It may also lead to improved anatomic reconstruction techniques given that the goal of such techniques is to replicate the knee's normal anatomy. Hence, the aim of this study was to investigate the microscopic anatomy of the ACL femoral enthesis and determine whether regional differences exist. METHODS Fifteen human ACL femoral entheses were histochemically processed and sectioned along the longitudinal axis of the ACL at 20, 40, 60, and 80 % of the width of the enthesis. Four thick sections (100 μm) per enthesis were prepared, stained, and digitized. From these sections, regional variations in the quantity of calcified and uncalcified fibrocartilage, the angle at which the ligament originates from the bone, and the shape profile of the tidemark were quantified. RESULTS At least 33 % more calcified fibrocartilage and 143 % more uncalcified fibrocartilage were found in the antero-inferior region, which corresponds to the inferior margin of the origin of the anteromedial ACL fibers, than all other regions (Ps < 0.05). In addition, the anteromedial fibers of the ACL originated from the femur at an angle six times greater than did its posterolateral fibers (P = 0.032). Finally, average entheseal tidemark profiles correlated bilaterally (Pearson's r = 0.79; P = 0.036), the most common profile being convex with a single re-entrant. CONCLUSIONS Systematic regional differences were found in fibrocartilage quantity and collagen fiber attachment angles. The marked differences may reflect differences in the loading history of the various regions of the ACL femoral enthesis. These differences, which could affect the potential for injury, should also be considered when developing new ACL reconstruction approaches.
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Affiliation(s)
- Mélanie L Beaulieu
- School of Kinesiology, University of Michigan, 1402 Washington Heights, Ann Arbor, MI, 48109, USA. .,Biomechanics Research Laboratory, Department of Mechanical Engineering, University of Michigan, 2350 Hayward Street, GG Brown Building, Ann Arbor, MI, 48109, USA.
| | - Grace E Carey
- School of Kinesiology, University of Michigan, 1402 Washington Heights, Ann Arbor, MI, 48109, USA.,Biomechanics Research Laboratory, Department of Mechanical Engineering, University of Michigan, 2350 Hayward Street, GG Brown Building, Ann Arbor, MI, 48109, USA
| | - Stephen H Schlecht
- Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI, 48109, USA
| | - Edward M Wojtys
- Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI, 48109, USA.,MedSport, University of Michigan, Domino's Farms, 24 Frank Lloyd Wright Drive, Lobby A, P.O. Box 391, Ann Arbor, MI, 48106, USA
| | - James A Ashton-Miller
- School of Kinesiology, University of Michigan, 1402 Washington Heights, Ann Arbor, MI, 48109, USA.,Biomechanics Research Laboratory, Department of Mechanical Engineering, University of Michigan, 2350 Hayward Street, GG Brown Building, Ann Arbor, MI, 48109, USA
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35
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Teuschl A, Heimel P, Nürnberger S, van Griensven M, Redl H, Nau T. A Novel Silk Fiber-Based Scaffold for Regeneration of the Anterior Cruciate Ligament: Histological Results From a Study in Sheep. Am J Sports Med 2016; 44:1547-57. [PMID: 26957219 DOI: 10.1177/0363546516631954] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Because of ongoing problems with anterior cruciate ligament (ACL) reconstruction, new approaches in the treatment of ACL injuries, particularly strategies based on tissue engineering, have gained increasing research interest. To allow for ACL regeneration, a structured scaffold that provides a mechanical basis, has cells from different sources, and comprises mechanical as well as biological factors is needed. Biological materials, biodegradable polymers, and composite materials are being used and tested as scaffolds. The optimal scaffold for ACL regeneration should be biocompatible and biodegradable to allow tissue ingrowth but also needs to have the right mechanical properties to provide immediate mechanical stability. HYPOTHESES The study hypotheses were that (1) a novel degradable silk fiber-based scaffold with mechanical properties similar to the native ACL will be able to initiate ligament regeneration after ACL resection and reconstruction under in vivo conditions and (2) additional cell seeding of the scaffold with autologous stromal vascular fraction-containing adipose-derived stem cells will increase regenerative activity. STUDY DESIGN Controlled laboratory study. METHODS A total of 33 mountain sheep underwent ACL resection and randomization to 2 experimental groups: (1) ACL reconstruction with a scaffold alone and (2) ACL reconstruction with a cell-seeded scaffold. Histological evaluation of the intra-articular portion of the reconstructed/regenerated ligament was performed after 6 and 12 months. RESULTS After 6 months, connective tissue surrounded the silk scaffold with ingrowth in some areas. The cell-seeded scaffolds had a significant lower silk content compared with the unseeded scaffolds and demonstrated a higher content of newly formed tissue. After 12 months, the density of the silk fibers decreased significantly, and the ingrowth of newly formed tissue increased in both groups. No differences between the 2 groups regarding silk fiber degradation and regenerated tissue were detected at 12 months. CONCLUSION The novel silk fiber-based scaffold was able to stimulate ACL regeneration under in vivo conditions. Additional cell seeding led to increased tissue regeneration and decreased silk fiber content at 6 months, whereas these differences were not present at 12 months. CLINICAL RELEVANCE ACL regeneration using a silk fiber-based scaffold with and without additional cell seeding may provide a new treatment option after joint injuries.
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Affiliation(s)
- Andreas Teuschl
- Department of Biochemical Engineering, University of Applied Sciences Technikum Wien, Vienna, Austria Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Center, Vienna, Austria Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Patrick Heimel
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Center, Vienna, Austria Karl Donath Laboratory for Hard Tissue and Biomaterial Research, Medical University of Vienna, Vienna, Austria
| | - Silvia Nürnberger
- Austrian Cluster for Tissue Regeneration, Vienna, Austria Department of Traumatology, Medical University of Vienna, Vienna, Austria
| | - Martijn van Griensven
- Department of Experimental Trauma Surgery, Technical University of Munich, Munich, Germany
| | - Heinz Redl
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Center, Vienna, Austria Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Thomas Nau
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Center, Vienna, Austria Austrian Cluster for Tissue Regeneration, Vienna, Austria
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36
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Leong NL, Kabir N, Arshi A, Nazemi A, Jiang J, Wu BM, Petrigliano FA, McAllister DR. Use of ultra-high molecular weight polycaprolactone scaffolds for ACL reconstruction. J Orthop Res 2016; 34:828-35. [PMID: 26497133 DOI: 10.1002/jor.23082] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/22/2015] [Indexed: 02/04/2023]
Abstract
Previously, we reported on the implantation of electrospun polycaprolactone (PCL) grafts for use in ACL tissue engineering in a small animal model. In the present study, we hypothesized that grafts fabricated from ultra-high molecular weight polycaprolactone (UHMWPCL) would have similarly favorable biologic properties but superior mechanical properties as compared to grafts fabricated from PCL. Two forms of polycaprolactone were obtained (UHMWPCL, MW = 500 kD, and PCL, MW = 80 kD) and electrospun into scaffolds that were used to perform ACL reconstruction in 7-8 week old male Lewis rats. The following groups were examined: UHMWPCL, PCL, flexor digitorum longus (FDL) allograft, native ACL, as well as sham surgery in which the ACL was transsected. At 16 weeks post-operatively, biomechanical testing, histology, and immunohistochemistry (IHC) were performed. Analysis of cellularity indicated that there was no significant difference among the UHMWPCL, PCL, and FDL allograft groups. Quantification of birefringence from picrosirius red staining demonstrated significantly more aligned collagen fibers in the allograft than the PCL group, but no difference between the UHMWPCL and allograft groups. The peak load to failure of the UHMWPCL grafts was significantly higher than PCL, and not significantly different from FDL allograft. This in vivo study establishes the superiority of the higher molecular weight version of polycaprolactone over PCL as a scaffold material for ACL reconstruction. By 16 weeks after implantation, the UHMWPCL grafts were not significantly different from the FDL allografts in terms of cellularity, peak load to failure, stiffness, and collagen fiber alignment. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:828-835, 2016.
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Affiliation(s)
- Natalie L Leong
- Department of Orthopaedic Surgery, University of California, Los Angeles, California
| | - Nima Kabir
- Department of Orthopaedic Surgery, University of California, Los Angeles, California
| | - Armin Arshi
- Department of Orthopaedic Surgery, University of California, Los Angeles, California
| | - Azadeh Nazemi
- Department of Biomedical Engineering, University of California, Los Angeles, California
| | - Jie Jiang
- Department of Orthopaedic Surgery, University of California, Los Angeles, California
| | - Ben M Wu
- Department of Biomedical Engineering, University of California, Los Angeles, California
| | - Frank A Petrigliano
- Department of Orthopaedic Surgery, University of California, Los Angeles, California
| | - David R McAllister
- Department of Orthopaedic Surgery, University of California, Los Angeles, California
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Leong NL, Kabir N, Arshi A, Nazemi A, Wu B, Petrigliano FA, McAllister DR. Evaluation of polycaprolactone scaffold with basic fibroblast growth factor and fibroblasts in an athymic rat model for anterior cruciate ligament reconstruction. Tissue Eng Part A 2015; 21:1859-68. [PMID: 25744933 DOI: 10.1089/ten.tea.2014.0366] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Anterior cruciate ligament (ACL) rupture is a common ligamentous injury often necessitating surgery. Current surgical treatment options include ligament reconstruction with autograft or allograft, which have their inherent limitations. Thus, there is interest in a tissue-engineered substitute for use in ACL regeneration. However, there have been relatively few in vivo studies to date. In this study, an athymic rat model of ACL reconstruction was used to evaluate electrospun polycaprolactone (PCL) grafts, with and without the addition of basic fibroblast growth factor (bFGF) and human foreskin fibroblasts. We examined the regenerative potential of tissue-engineered ACL grafts using histology, immunohistochemistry, and mechanical testing up to 16 weeks postoperatively. Histology showed infiltration of the grafts with cells, and immunohistochemistry demonstrated aligned collagen deposition with minimal inflammatory reaction. Mechanical testing of the grafts demonstrated significantly higher mechanical properties than immediately postimplantation. Acellular grafts loaded with bFGF achieved 58.8% of the stiffness and 40.7% of the peak load of healthy native ACL. Grafts without bFGF achieved 31.3% of the stiffness and 28.2% of the peak load of healthy native ACL. In this in vivo rodent model study for ACL reconstruction, the histological and mechanical evaluation demonstrated excellent healing and regenerative potential of our electrospun PCL ligament graft.
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Affiliation(s)
- Natalie Luanne Leong
- 1Department of Orthopedic Surgery, University of California, Los Angeles, Los Angeles, California
| | - Nima Kabir
- 1Department of Orthopedic Surgery, University of California, Los Angeles, Los Angeles, California
| | - Armin Arshi
- 1Department of Orthopedic Surgery, University of California, Los Angeles, Los Angeles, California
| | - Azadeh Nazemi
- 2Department of Bioengineering, University of California, Los Angeles, Los Angeles, California
| | - Ben Wu
- 2Department of Bioengineering, University of California, Los Angeles, Los Angeles, California
| | - Frank A Petrigliano
- 1Department of Orthopedic Surgery, University of California, Los Angeles, Los Angeles, California
| | - David R McAllister
- 1Department of Orthopedic Surgery, University of California, Los Angeles, Los Angeles, California
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Leong NL, Arshi A, Kabir N, Nazemi A, Petrigliano FA, Wu BM, McAllister DR. In vitro and in vivo evaluation of heparin mediated growth factor release from tissue-engineered constructs for anterior cruciate ligament reconstruction. J Orthop Res 2015; 33:229-36. [PMID: 25363620 DOI: 10.1002/jor.22757] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 09/29/2014] [Indexed: 02/04/2023]
Abstract
Anterior cruciate ligament (ACL) rupture is a common injury often necessitating surgical treatment with graft reconstruction. Due to limitations associated with current graft options, there is interest in a tissue-engineered substitute for use in ACL regeneration. While they represent an important step in translation to clinical practice, relatively few in vivo studies have been performed to evaluate tissue-engineered ACL grafts. In the present study, we immobilized heparin onto electrospun polycaprolactone scaffolds as a means of incorporating basic fibroblast growth factor (bFGF) onto the scaffold. In vitro, we demonstrated that human foreskin fibroblasts (HFFs) cultured on bFGF-coated scaffolds had significantly greater cell proliferation. In vivo, we implanted electrospun polycaprolactone grafts with and without bFGF into athymic rat knees. We analyzed the regenerated ACL using histological methods up to 16 weeks post-implantation. Hematoxylin and eosin staining demonstrated infiltration of the grafts with cells, and picrosirius red staining demonstrated aligned collagen fibers. At 16 weeks postop, mechanical testing of the grafts demonstrated that the grafts had approximately 30% the maximum load to failure of the native ACL. However, there were no significant differences observed between the graft groups with or without heparin-immobilized bFGF. While this study demonstrates the potential of a regenerative medicine approach to treatment of ACL rupture, it also demonstrates that in vitro results do not always predict what will occur in vivo.
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Affiliation(s)
- Natalie L Leong
- Department of Orthopaedic Surgery, University of California, Los Angeles, California
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Nau T, Teuschl A. Regeneration of the anterior cruciate ligament: Current strategies in tissue engineering. World J Orthop 2015; 6:127-136. [PMID: 25621217 PMCID: PMC4303781 DOI: 10.5312/wjo.v6.i1.127] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 06/19/2014] [Accepted: 07/29/2014] [Indexed: 02/06/2023] Open
Abstract
Recent advancements in the field of musculoskeletal tissue engineering have raised an increasing interest in the regeneration of the anterior cruciate ligament (ACL). It is the aim of this article to review the current research efforts and highlight promising tissue engineering strategies. The four main components of tissue engineering also apply in several ACL regeneration research efforts. Scaffolds from biological materials, biodegradable polymers and composite materials are used. The main cell sources are mesenchymal stem cells and ACL fibroblasts. In addition, growth factors and mechanical stimuli are applied. So far, the regenerated ACL constructs have been tested in a few animal studies and the results are encouraging. The different strategies, from in vitro ACL regeneration in bioreactor systems to bio-enhanced repair and regeneration, are under constant development. We expect considerable progress in the near future that will result in a realistic option for ACL surgery soon.
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Mahalingam VD, Behbahani-Nejad N, Horine SV, Olsen TJ, Smietana MJ, Wojtys EM, Wellik DM, Arruda EM, Larkin LM. Allogeneic versus autologous derived cell sources for use in engineered bone-ligament-bone grafts in sheep anterior cruciate ligament repair. Tissue Eng Part A 2015; 21:1047-54. [PMID: 25397361 DOI: 10.1089/ten.tea.2014.0422] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The use of autografts versus allografts for anterior cruciate ligament (ACL) reconstruction is controversial. The current popular options for ACL reconstruction are patellar tendon or hamstring autografts, yet advances in allograft technologies have made allogeneic grafts a favorable option for repair tissue. Despite this, the mismatched biomechanical properties and risk of osteoarthritis resulting from the current graft technologies have prompted the investigation of new tissue sources for ACL reconstruction. Previous work by our lab has demonstrated that tissue-engineered bone-ligament-bone (BLB) constructs generated from an allogeneic cell source develop structural and functional properties similar to those of native ACL and vascular and neural structures that exceed those of autologous patellar tendon grafts. In this study, we investigated the effectiveness of our tissue-engineered ligament constructs fabricated from autologous versus allogeneic cell sources. Our preliminary results demonstrate that 6 months postimplantation, our tissue-engineered auto- and allogeneic BLB grafts show similar histological and mechanical outcomes indicating that the autologous grafts are a viable option for ACL reconstruction. These data indicate that our tissue-engineered autologous ligament graft could be used in clinical situations where immune rejection and disease transmission may preclude allograft use.
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Affiliation(s)
- Vasudevan D Mahalingam
- 1 Department of Molecular and Integrative Physiology, University of Michigan , Ann Arbor, Michigan
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Petrigliano FA, Arom GA, Nazemi AN, Yeranosian MG, Wu BM, McAllister DR. In vivo evaluation of electrospun polycaprolactone graft for anterior cruciate ligament engineering. Tissue Eng Part A 2015; 21:1228-36. [PMID: 25412879 DOI: 10.1089/ten.tea.2013.0482] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The anterior cruciate ligament (ACL) is critical for the structural stability of the knee and its injury often requires surgical intervention. Because current reconstruction methods using autograft or allograft tissue suffer from donor-site morbidity and limited supply, there has been emerging interest in the use of bioengineered materials as a platform for ligament reconstruction. Here, we report the use of electrospun polycaprolactone (PCL) scaffolds as a candidate platform for ACL reconstruction in an in vivo rodent model. Electrospun PCL was fabricated and laser cut to facilitate induction of cells and collagen deposition and used to reconstruct the rat ACL. Histological analysis at 2, 6, and 12 weeks postimplantation revealed biological integration, minimal immune response, and the gradual infiltration of collagen in both the bone tunnel and intra-articular regions of the scaffold. Biomechanical testing demonstrated that the PCL graft failure load and stiffness at 12 weeks postimplantation (13.27±4.20N, 15.98±5.03 N/mm) increased compared to time zero testing (3.95±0.33N, 1.95±0.35 N/mm). Taken together, these results suggest that electrospun PCL serves as a biocompatible graft for ACL reconstruction with the capacity to facilitate collagen deposition.
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Affiliation(s)
- Frank A Petrigliano
- 1 Department of Orthopaedic Surgery, David Geffen School of Medicine at University of California at Los Angeles , Los Angeles, California
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Mahalingam VD, Behbahani-Nejad N, Ronan EA, Olsen TJ, Smietana MJ, Wojtys EM, Wellik DM, Arruda EM, Larkin LM. Fresh versus frozen engineered bone-ligament-bone grafts for sheep anterior cruciate ligament repair. Tissue Eng Part C Methods 2014; 21:548-56. [PMID: 25397990 DOI: 10.1089/ten.tec.2014.0542] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Surgical intervention is often required to restore knee instability in patients with anterior cruciate ligament (ACL) injury. The most commonly used grafts for ACL reconstruction are tendon autografts or allografts. These current options, however, have shown failure rates requiring revision and continued instability in the long term. The mismatched biomechanical properties of the current tendon grafts compared with native ACL tissue are thought to contribute to these poor outcomes and potential risk of early onset osteoarthritis. As a possible solution to these issues, our laboratory has fabricated tissue-engineered ligament constructs that exhibit structural and functional properties similar to those of native ACL tissue after 6 months implantation. In addition, these tissue-engineered grafts achieve vascular and neural development that exceeds those of patellar tendon grafts. However, the utility of our tissue-engineered grafts is limited by the labor-intensive method required to produce the constructs and the need to use the constructs fresh, directly from the cell culturing system. Ideally, these constructs would be fabricated and stored until needed. Thus, in this study, we investigated the efficacy of freezing our tissue-engineered constructs as a method of preservation before use for ACL reconstruction. We hypothesized that frozen constructs would have similar histological and biomechanical outcomes compared with our fresh model. Our results showed that 6 months postimplantation as an ACL replacement graft, both our tissue-engineered fresh and frozen grafts demonstrated similar mechanical and histological outcomes, indicating that freezing is a suitable method for preserving and storing our graft before ACL reconstruction. The ability to use frozen constructs significantly increases the versatility of our graft technology expanding the clinical utility of our graft.
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Affiliation(s)
- Vasudevan D Mahalingam
- 1Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Nilofar Behbahani-Nejad
- 1Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Elizabeth A Ronan
- 1Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Tyler J Olsen
- 2Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan
| | - Michael J Smietana
- 3Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan
| | - Edward M Wojtys
- 4Medsport Sports Medicine Program, Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan
| | - Deneen M Wellik
- 5Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan.,6Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Ellen M Arruda
- 2Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan.,3Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan.,7Program in Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan
| | - Lisa M Larkin
- 1Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan.,3Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan
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43
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Engineering complex orthopaedic tissues via strategic biomimicry. Ann Biomed Eng 2014; 43:697-717. [PMID: 25465616 DOI: 10.1007/s10439-014-1190-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 11/13/2014] [Indexed: 12/13/2022]
Abstract
The primary current challenge in regenerative engineering resides in the simultaneous formation of more than one type of tissue, as well as their functional assembly into complex tissues or organ systems. Tissue-tissue synchrony is especially important in the musculoskeletal system, wherein overall organ function is enabled by the seamless integration of bone with soft tissues such as ligament, tendon, or cartilage, as well as the integration of muscle with tendon. Therefore, in lieu of a traditional single-tissue system (e.g., bone, ligament), composite tissue scaffold designs for the regeneration of functional connective tissue units (e.g., bone-ligament-bone) are being actively investigated. Closely related is the effort to re-establish tissue-tissue interfaces, which is essential for joining these tissue building blocks and facilitating host integration. Much of the research at the forefront of the field has centered on bioinspired stratified or gradient scaffold designs which aim to recapitulate the structural and compositional inhomogeneity inherent across distinct tissue regions. As such, given the complexity of these musculoskeletal tissue units, the key question is how to identify the most relevant parameters for recapitulating the native structure-function relationships in the scaffold design. Therefore, the focus of this review, in addition to presenting the state-of-the-art in complex scaffold design, is to explore how strategic biomimicry can be applied in engineering tissue connectivity. The objective of strategic biomimicry is to avoid over-engineering by establishing what needs to be learned from nature and defining the essential matrix characteristics that must be reproduced in scaffold design. Application of this engineering strategy for the regeneration of the most common musculoskeletal tissue units (e.g., bone-ligament-bone, muscle-tendon-bone, cartilage-bone) will be discussed in this review. It is anticipated that these exciting efforts will enable integrative and functional repair of soft tissue injuries, and moreover, lay the foundation for the development of composite tissue systems and ultimately, total limb or joint regeneration.
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44
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Vaquette C. Biomaterial Structures for Anterior Cruciate Ligament Replacement. Biomaterials 2014. [DOI: 10.1002/9781119043553.ch7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Mertens JP, Sugg KB, Lee JD, Larkin LM. Engineering muscle constructs for the creation of functional engineered musculoskeletal tissue. Regen Med 2014; 9:89-100. [PMID: 24351009 DOI: 10.2217/rme.13.81] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Volumetric muscle loss (VML) is a disabling condition in which current clinical procedures are suboptimal. The field of tissue engineering has many promising strategies for the creation of functional skeletal muscle in vitro. However, there are still two key limitations that prevent it from becoming a solution for treating VML. First, engineered muscle tissue must be biocompatible to facilitate muscle tissue regrowth without generating an immune response. Second, engineered muscle constructs must be scaled up to facilitate replacement of clinically relevant volumes of tissue (centimeters in diameter). There are currently no tissue engineering strategies to produce tissue constructs that are both biocompatible and large enough to facilitate clinical repair. However, recent advances in tissue engineering using synthetic scaffolds, native scaffolds, or scaffold-free approaches may lead to a solution for repair of VML injuries.
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Affiliation(s)
- Jacob P Mertens
- Molecular & Integrative Physiology, University of Michigan, MI, USA
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46
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VanDusen KW, Syverud BC, Williams ML, Lee JD, Larkin LM. Engineered skeletal muscle units for repair of volumetric muscle loss in the tibialis anterior muscle of a rat. Tissue Eng Part A 2014; 20:2920-30. [PMID: 24813922 DOI: 10.1089/ten.tea.2014.0060] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Volumetric muscle loss (VML) is the traumatic, degenerative, or surgical loss of muscle tissue, which may result in function loss and physical deformity. To date, clinical treatments for VML--the reflected muscle flap or transferred muscle graft--are limited by tissue availability and donor site morbidity. To address the need for more innovative skeletal muscle repair options, our laboratory has developed scaffoldless tissue-engineered skeletal muscle units (SMUs), multiphasic tissue constructs composed of engineered skeletal muscle with engineered bone-tendon ends, myotendinous junctions, and entheses, which in vitro can produce force both spontaneously and in response to electrical stimulation. Though phenotypically immature in vitro, we have shown that following 1 week of implantation in an ectopic site, our muscle constructs develop vascularization and innervation, an epimysium-like outer layer of connective tissue, an increase in myosin protein content, formation of myofibers, and increased force production. These findings suggest that our engineered muscle tissue survives implantation and develops the interfaces necessary to advance the phenotype toward adult muscle. The purpose of this study was to evaluate the potential of our SMUs to restore muscle tissue to sites of acute VML. Our results indicate that our SMUs continue to mature in vivo with longer recovery times and have the potential to repair VML sites by providing additional muscle fibers to damaged muscles. We conclude from this study that our SMUs have the potential to restore lost tissue volume in cases of acute VML.
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Affiliation(s)
- Keith W VanDusen
- 1 Department of Molecular and Integrated Physiology, University of Michigan , Ann Arbor, Michigan
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Zhao L, Thambyah A, Broom ND. A multi-scale structural study of the porcine anterior cruciate ligament tibial enthesis. J Anat 2014; 224:624-33. [PMID: 24697495 PMCID: PMC4025890 DOI: 10.1111/joa.12174] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/20/2014] [Indexed: 12/16/2022] Open
Abstract
Like the human anterior cruciate ligament (ACL), the porcine ACL also has a double bundle structure and several biomechanical studies using this model have been carried out to show the differential effect of these two bundles on macro-level knee joint function. It is hypothesised that if the different bundles of the porcine ACL are mechanically distinct in function, then a multi-scale anatomical characterisation of their individual enthesis will also reveal significant differences in structure between the bundles. Twenty-two porcine knee joints were cleared of their musculature to expose the intact ACL following which ligament-bone samples were obtained. The samples were fixed in formalin followed by decalcification with formic acid. Thin sections containing the ligament insertion into the tibia were then obtained by cryosectioning and analysed using differential interference contrast (DIC) optical microscopy and scanning electron microscopy (SEM). At the micro-level, the anteromedial (AM) bundle insertion at the tibia displayed a significant deep-rooted interdigitation into bone, while for the posterolateral (PL) bundle the fibre insertions were less distributed and more focal. Three sub-types of enthesis were identified in the ACL and related to (i) bundle type, (ii) positional aspect within the insertion, and (iii) specific bundle function. At the nano-level the fibrils of the AM bundle were significantly larger than those in the PL bundle. The modes by which the AM and PL fibrils merged with the bone matrix fibrils were significantly different. A biomechanical interpretation of the data suggests that the porcine ACL enthesis is a specialized, functionally graded structural continuum, adapted at the micro-to-nano scales to serve joint function at the macro level.
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Affiliation(s)
- Lei Zhao
- Department of Chemical and Materials Engineering, The University of AucklandAuckland, New Zealand
| | - Ashvin Thambyah
- Department of Chemical and Materials Engineering, The University of AucklandAuckland, New Zealand
| | - Neil D Broom
- Department of Chemical and Materials Engineering, The University of AucklandAuckland, New Zealand
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48
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Yang G, Rothrauff BB, Tuan RS. Tendon and ligament regeneration and repair: clinical relevance and developmental paradigm. ACTA ACUST UNITED AC 2014; 99:203-222. [PMID: 24078497 DOI: 10.1002/bdrc.21041] [Citation(s) in RCA: 291] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Revised: 07/27/2013] [Accepted: 07/27/2013] [Indexed: 12/18/2022]
Abstract
As dense connective tissues connecting bone to muscle and bone to bone, respectively, tendon and ligament (T/L) arise from the somitic mesoderm, originating in a recently discovered somitic compartment, the syndetome. Inductive signals from the adjacent sclerotome and myotome upregulate expression of Scleraxis, a key transcription factor for tenogenic and ligamentogenic differentiation. Understanding T/L development is critical to establishing a knowledge base for improving the healing and repair of T/L injuries, a high-burden disease due to the intrinsically poor natural healing response. Current treatment of the three most common tendon injuries-tearing of the rotator cuff of the shoulder, flexor tendon of the hand, and Achilles tendon-include mostly surgical repair and/or conservative approaches, including biophysical modalities such as rehabilitation and cryotherapy. Unfortunately, the fibrovascular scar formed during healing possesses inferior mechanical and biochemical properties, resulting in compromised tissue functionality. Regenerative approaches have sought to augment the injured tissue with cells, scaffolds, bioactive agents, and mechanical stimulation to improve the natural healing response. The key challenges in restoring full T/L function following injury include optimal combination of these biological agents as well as their delivery to the injury site. A greater understanding of the molecular mechanisms involved in T/L development and natural healing, coupled with the capability of producing complex biomaterials to deliver multiple biofactors with high spatiotemporal resolution and specificity, should lead to regenerative procedures that more closely recapitulate T/L morphogenesis, thereby offering future patients the prospect of T/L regeneration, as opposed to simple tissue repair.
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Affiliation(s)
- Guang Yang
- Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
| | - Benjamin B Rothrauff
- Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
| | - Rocky S Tuan
- Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
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49
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Koburger S, Bannerman A, Grover LM, Müller FA, Bowen J, Paxton JZ. A novel method for monitoring mineralisation in hydrogels at the engineered hard–soft tissue interface. Biomater Sci 2014; 2:41-51. [DOI: 10.1039/c3bm60102a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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50
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Proffen BL, Fleming BC, Murray MM. Histologic Predictors of Maximum Failure Loads Differ between the Healing ACL and ACL Grafts after 6 and 12 Months In Vivo. Orthop J Sports Med 2013; 1. [PMID: 25343145 PMCID: PMC4203461 DOI: 10.1177/2325967113512457] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Background: Bioenhanced anterior cruciate ligament (ACL) repair, where the suture repair is supplemented with a biological scaffold, is a promising novel technique to stimulate healing after ACL rupture. However, the histological properties of a successfully healing ACL and how they relate to the mechanical properties have not been fully described. Purpose: To determine which histological features best correlate with the mechanical properties of the healing ACL repairs and ACL grafts in a porcine model at 6 and 12 months after injury. Study Design: Controlled laboratory study. Methods: A total of 48 Yucatan mini-pigs underwent ACL transection followed by: (1) conventional ACL reconstruction with bone–patellar tendon–bone (BPTB) allograft, (2) bioenhanced ACL reconstruction with BPTB allograft using a bioactive scaffold, or (3) bioenhanced ACL repair using the same bioactive scaffold. After 6 and 12 months of healing, structural properties of the ACL or graft (yield and failure load, linear stiffness) were measured. Following mechanical testing, ACL specimens were histologically analyzed for cell and vascular density and qualitatively assessed using the advanced Ligament Maturity Index. Results: After 6 months of healing, the cellular organization subscore was most predictive of yield load (r2 = 0.98), maximum load (r2 = 0.89), and linear stiffness (r2 = 0.95) of the healing ACL, while at 12 months, the collagen subscore (r2 = 0.68) became the best predictor of maximum load. For ACL grafts, the reverse was true, with the collagen subscore predictive of yield and maximum loads at 6 months (r2 = 0.55) and graft cellularity predictive of maximum load of the graft at 12 months (r2 = 0.50). Conclusion: These findings suggest there may be key biological differences in development and maintenance of ACL tissue after repair or reconstruction, with early ligament function dependent on cellular population of the repair but early graft function dependent on the maintenance of organized collagen. Clinical Relevance: Bioenhanced ACL repair shows promising potential as an alternative clinical treatment for ACL injury. This study contributes to the understanding of the cellular contribution to mechanical characteristics of the healing ACL in both repaired and reconstructed ACLs.
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Affiliation(s)
- B L Proffen
- Boston Children's Hospital, Department of Orthopaedic Surgery, Harvard School of Medicine
| | - B C Fleming
- Rhode Island Hospital, Department of Orthopaedics, Warren Alpert Medical School, Brown University
| | - M M Murray
- Boston Children's Hospital, Department of Orthopaedic Surgery, Harvard School of Medicine
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