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Arvayo AL, Imbrie-Moore A, Levenston ME. Rapid and durable photochemical bonding of cartilage using the porphyrin photosensitizer verteporfin. Osteoarthritis Cartilage 2019; 27:1537-1544. [PMID: 31229683 PMCID: PMC7409723 DOI: 10.1016/j.joca.2019.05.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 05/17/2019] [Accepted: 05/21/2019] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To evaluate the effectiveness of verteporfin as a photosensitizer to photochemically bond articular cartilage tissues and determine bond durability in vitro. DESIGN Bond strength induced by verteporfin over a range of concentrations and light exposure conditions was investigated using a disk-annulus model and a pushout test. Exposure was parameterized by varying either irradiance or irradiation time. Bond robustness in a cell-mediated degeneration environment was examined by exposing newly bonded samples to interleukin-1 alpha for the first 4 days of a 7-day culture period, followed by mechanical testing and biochemical and cellular viability assays. RESULTS Photochemical bonding using verteporfin produced high bonding shear strengths at relatively low photosensitizer concentrations. Low exposures produced by either low irradiance or short irradiation time were sufficient to produce shear strengths comparable to those previously produced with phthalocyanine photosensitizers with substantially higher light exposure. Photochemically produced bonds were resistant to cell-mediated degeneration in vitro with no evident differences in cell viability among treatments. CONCLUSIONS Verteporfin offers distinct advantages as a photosensitizer for photochemical bonding of articular cartilage due to the production of strong, durable bonds at relatively low light exposures. Further exploration may lead to clinically feasible strategies to augment cartilage repair techniques.
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Affiliation(s)
- Alberto L Arvayo
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
| | | | - Marc E Levenston
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305,Corresponding Author: Marc E. Levenston, Building 520 Rm 225, Stanford University, Stanford, CA 94305-4038, United States, Tel: 1-650-723-9464, Fax: 1-650-725-1587,
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Liebesny PH, Mroszczyk K, Zlotnick H, Hung HH, Frank E, Kurz B, Zanotto G, Frisbie D, Grodzinsky AJ. Enzyme Pretreatment plus Locally Delivered HB-IGF-1 Stimulate Integrative Cartilage Repair In Vitro. Tissue Eng Part A 2019; 25:1191-1201. [PMID: 31237484 PMCID: PMC6760182 DOI: 10.1089/ten.tea.2019.0013] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 04/10/2019] [Indexed: 01/20/2023] Open
Abstract
IMPACT STATEMENT A critical attribute for the long-term success of cartilage defect repair is the strong integration between the repair tissue and the surrounding native tissue. Current approaches utilized by physicians fail to achieve this attribute, leading to eventual relapse of the defect. This article demonstrates the concept of a simple, clinically viable approach for enhancing tissue integration via the combination of a safe, transient enzymatic treatment with a locally delivered, retained growth factor through an in vitro hydrogel/cartilage explant model.
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Affiliation(s)
- Paul H. Liebesny
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Keri Mroszczyk
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Hannah Zlotnick
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Han-Hwa Hung
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Eliot Frank
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Bodo Kurz
- Anatomical Institute, University of Kiel, Kiel, Germany
| | - Gustavo Zanotto
- Department of Clinical Sciences, Orthopaedic Research Center, Colorado State University, Fort Collins, Colorado
| | - David Frisbie
- Department of Clinical Sciences, Orthopaedic Research Center, Colorado State University, Fort Collins, Colorado
| | - Alan J. Grodzinsky
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts
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3
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Microporous acellular extracellular matrix combined with adipose-derived stem cell sheets as a promising tissue patch promoting articular cartilage regeneration and interface integration. Cytotherapy 2019; 21:856-869. [DOI: 10.1016/j.jcyt.2019.02.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 01/04/2019] [Accepted: 02/07/2019] [Indexed: 11/20/2022]
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Richmon JD, Sage AB, Wong VW, Chen AC, Pan C, Sah RL, Watson D. Tensile Biomechanical Properties of Human Nasal Septal Cartilage. ACTA ACUST UNITED AC 2018. [DOI: 10.1177/194589240501900616] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background The biomechanical properties of human septal cartilage have yet to be fully defined and thereby limits our ability to compare tissue-engineered constructs to native tissue. In this study, we analyzed the tensile properties of human nasal septal cartilage with respect to axis of tension, age group, and gender. Methods Fifty-five tensile tests were run on human septal specimens obtained from 28 patients. Samples obtained in the vertical and anterior–posterior (both above and within the maxillary crest) axes were subjected to equilibrium and dynamic tensile testing. Results The average values for strength, failure strain, equilibrium modulus and dynamic modulus were not found to be significantly different with respect to axis of tension testing, age group, or gender. Tensile results for septal cartilage were as follows: equilibrium modulus 3.01 ± 0.39 MPa, dynamic modulus 4.99 ± 0.49 MPa, strength 1.90 ± 0.24 MPa, and failure strain 0.35 ± 0.03 mm/mm. Conclusion We confirm that septal cartilage has weaker tensile properties compared to articular cartilage and found no difference in strength with respect to age, gender, or axis of tension (isotropic).
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Affiliation(s)
- Jeremy D. Richmon
- Division of Otolaryngology–Head and Neck Surgery, University of California, San Diego, California
| | - August B. Sage
- Department of Bioengineering and Whitaker Institute of Biomedical Engineering, University of California, San Diego, California
| | - Van W. Wong
- Department of Bioengineering and Whitaker Institute of Biomedical Engineering, University of California, San Diego, California
| | - Albert C. Chen
- Department of Bioengineering and Whitaker Institute of Biomedical Engineering, University of California, San Diego, California
| | - Christine Pan
- Department of Bioengineering and Whitaker Institute of Biomedical Engineering, University of California, San Diego, California
| | - Robert L. Sah
- Department of Bioengineering and Whitaker Institute of Biomedical Engineering, University of California, San Diego, California
| | - Deborah Watson
- Division of Otolaryngology–Head and Neck Surgery, University of California, San Diego, California
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Tan AR, Hung CT. Concise Review: Mesenchymal Stem Cells for Functional Cartilage Tissue Engineering: Taking Cues from Chondrocyte-Based Constructs. Stem Cells Transl Med 2017; 6:1295-1303. [PMID: 28177194 PMCID: PMC5442836 DOI: 10.1002/sctm.16-0271] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 12/21/2016] [Indexed: 01/01/2023] Open
Abstract
Osteoarthritis, the most prevalent form of joint disease, afflicts 9% of the U.S. population over the age of 30 and costs the economy nearly $100 billion annually in healthcare and socioeconomic costs. It is characterized by joint pain and dysfunction, though the pathophysiology remains largely unknown. Due to its avascular nature and limited cellularity, articular cartilage exhibits a poor intrinsic healing response following injury. As such, significant research efforts are aimed at producing engineered cartilage as a cell-based approach for articular cartilage repair. However, the knee joint is mechanically demanding, and during injury, also a milieu of harsh inflammatory agents. The unforgiving mechano-chemical environment requires tissue replacements that are capable of bearing such burdens. The use of mesenchymal stem cells (MSCs) for cartilage tissue engineering has emerged as a promising cell source due to their ease of isolation, capacity to readily expand in culture, and ability to undergo lineage-specific differentiation into chondrocytes. However, to date, very few studies utilizing MSCs have successfully recapitulated the structural and functional properties of native cartilage, exposing the difficult process of uniformly differentiating stem cells into desired cell fates and maintaining the phenotype during in vitro culture and after in vivo implantation. To address these shortcomings, here, we present a concise review on modulating stem cell behavior, tissue development and function using well-developed techniques from chondrocyte-based cartilage tissue engineering. Stem Cells Translational Medicine 2017;6:1295-1303.
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Zhao X, Papadopoulos A, Ibusuki S, Bichara DA, Saris DB, Malda J, Anseth KS, Gill TJ, Randolph MA. Articular cartilage generation applying PEG-LA-DM/PEGDM copolymer hydrogels. BMC Musculoskelet Disord 2016; 17:245. [PMID: 27255078 PMCID: PMC4891826 DOI: 10.1186/s12891-016-1100-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 05/26/2016] [Indexed: 12/04/2022] Open
Abstract
Background Injuries to the human native cartilage tissue are particularly problematic because cartilage has little to no ability to heal or regenerate itself. Employing a tissue engineering strategy that combines suitable cell sources and biomimetic hydrogels could be a promising alternative to achieve cartilage regeneration. However, the weak mechanical properties may be the major drawback to use fully degradable hydrogels. Besides, most of the fully degradable hydrogels degrade too fast to permit enough extracellular matrix (ECM) production for neocartilage formation. In this study, we demonstrated the feasibility of neocartilage regeneration using swine articular chondrocytes photoencapsualted into poly (ethylene glycol) dimethacrylate (PEGDM) copolymer hydrogels composed of different degradation profiles: degradable (PEG-LA-DM) and nondegradable (PEGDM) macromers in molar ratios of 50/50, 60/40, 70/30, 80/20, and 90/10. Methods Articular chondrocytes were isolated enzymatically from juvenile Yorkshire swine cartilage. 6 × 107 cells cells were added to each milliliter of macromer/photoinitiator (I2959) solution. Nonpolymerized gel containing the cells (100 μL) was placed in cylindrical molds (4.5 mm diameter × 6.5 mm in height). The macromer/photoinitiator/chondrocyte solutions were polymerized using ultraviolet (365 nm) light at 10 mW/cm2 for 10 mins. Also, an articular cartilaginous ring model was used to examine the capacity of the engineered cartilage to integrate with native cartilage. Samples in the pilot study were collected at 6 weeks. Samples in the long-term experimental groups (60/40 and 70/30) were implanted into nude mice subcutaneously and harvested at 6, 12 and 18 weeks. Additionally, cylindrical constructs that were not implanted used as time zero controls. All of the harvested specimens were examined grossly and analyzed histologically and biochemically. Results Histologically, the neocartilage formed in the photochemically crosslinked gels resembled native articular cartilage with chondrocytes in lacunae and surrounded by new ECM. Increases in total DNA, glycosaminoglycan, and hydroxyproline were observed over the time periods studied. The neocartilage integrated with existing native cartilage. Conclusions Articular cartilage generation was achieved using swine articular chondrocytes photoencapsulated in copolymer PEGDM hydrogels, and the neocartilage tissue had the ability to integrate with existing adjacent native cartilage.
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Affiliation(s)
- Xing Zhao
- Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.,Division of Plastic Surgery, Massachusetts General Hospital, Harvard Medical School, WACC 435, 15 Parkman Street, Boston, MA, 02114, USA.,Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Anestis Papadopoulos
- Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Shinichi Ibusuki
- Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - David A Bichara
- Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.,Division of Plastic Surgery, Massachusetts General Hospital, Harvard Medical School, WACC 435, 15 Parkman Street, Boston, MA, 02114, USA
| | - Daniel B Saris
- Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands.,MIRA Institute for Biotechnology and Technical Medicine, University Twente, Enschede, The Netherlands
| | - Jos Malda
- Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands.,Department of Equine Science, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Kristi S Anseth
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, USA
| | - Thomas J Gill
- Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Mark A Randolph
- Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. .,Division of Plastic Surgery, Massachusetts General Hospital, Harvard Medical School, WACC 435, 15 Parkman Street, Boston, MA, 02114, USA.
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7
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Theodoropoulos JS, DeCroos AJN, Petrera M, Park S, Kandel RA. Mechanical stimulation enhances integration in an in vitro model of cartilage repair. Knee Surg Sports Traumatol Arthrosc 2016; 24:2055-64. [PMID: 25173505 DOI: 10.1007/s00167-014-3250-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 08/15/2014] [Indexed: 12/18/2022]
Abstract
PURPOSE (1) To characterize the effects of mechanical stimulation on the integration of a tissue-engineered construct in terms of histology, biochemistry and biomechanical properties; (2) to identify whether cells of the implant or host tissue were critical to implant integration; and (3) to study cells believed to be involved in lateral integration of tissue-engineered cartilage to host cartilage. We hypothesized that mechanical stimulation would enhance the integration of the repair implant with host cartilage in an in vitro integration model. METHODS Articular cartilage was harvested from 6- to 9-month-old bovine metacarpal-phalangeal joints. Constructs composed of tissue-engineered cartilage implanted into host cartilage were placed in spinner bioreactors and maintained on a magnetic stir plate at either 0 (static control) or 90 (experimental) rotations per minute (RPM). The constructs from both the static and spinner bioreactors were harvested after either 2 or 4 weeks of culture and evaluated histologically, biochemically, biomechanically and for gene expression. RESULTS The extent and strength of integration between tissue-engineered cartilage and native cartilage improved significantly with both time and mechanical stimulation. Integration did not occur if the implant was not viable. The presence of stimulation led to a significant increase in collagen content in the integration zone between host and implant at 2 weeks. The gene profile of cells in the integration zone differs from host cartilage demonstrating an increase in the expression of membrane type 1 matrix metalloproteinase (MT1-MMP), aggrecan and type II collagen. CONCLUSIONS This study shows that the integration of in vitro tissue-engineered implants with host tissue improves with mechanical stimulation. The findings of this study suggests that consideration should be given to implementing early loading (mechanical stimulation) into future in vivo studies investigating the long-term viability and integration of tissue-engineered cartilage for the treatment of cartilage injuries. This could simply be done through the use of continuous passive motion (CPM) in the post-operative period or through a more complex and structured rehabilitation program with a gradual increase in forces across the joint over time.
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Affiliation(s)
- John S Theodoropoulos
- University of Toronto Orthopaedic Sports Medicine Program, Mount Sinai Hospital and Women's College Hospital, Room 476C, 600 University Ave, Toronto, ON, M5G 1X5, Canada.
| | - Amritha J N DeCroos
- Bioengineering of Skeletal Tissues Team, Division of Pathology and Laboratory Medicine, Mount Sinai Hospital, 600 University Ave, Toronto, ON, M5G 1X5, Canada
| | - Massimo Petrera
- University of Toronto Orthopaedic Sports Medicine Program, Mount Sinai Hospital and Women's College Hospital, Room 476C, 600 University Ave, Toronto, ON, M5G 1X5, Canada
| | - Sam Park
- University of Toronto Orthopaedic Sports Medicine Program, Mount Sinai Hospital and Women's College Hospital, Room 476C, 600 University Ave, Toronto, ON, M5G 1X5, Canada
| | - Rita A Kandel
- Bioengineering of Skeletal Tissues Team, Division of Pathology and Laboratory Medicine, Mount Sinai Hospital, 600 University Ave, Toronto, ON, M5G 1X5, Canada
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Cartilage repair using mesenchymal stem cell (MSC) sheet and MSCs-loaded bilayer PLGA scaffold in a rabbit model. Knee Surg Sports Traumatol Arthrosc 2014; 22:1424-33. [PMID: 23108680 DOI: 10.1007/s00167-012-2256-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2012] [Accepted: 10/15/2012] [Indexed: 10/27/2022]
Abstract
PURPOSE The integration of regenerated cartilage with surrounding native cartilage is a major challenge for the success of cartilage tissue-engineering strategies. The purpose of this study is to investigate whether incorporation of the power of mesenchymal stem cell (MSC) sheet to MSCs-loaded bilayer poly-(lactic-co-glycolic acid) (PLGA) scaffolds can improve the integration and repair of cartilage defects in a rabbit model. METHODS Rabbit bone marrow-derived MSCs were cultured and formed cell sheet. Full-thickness cylindrical osteochondral defects (4 mm in diameter, 3 mm in depth) were created in the patellar groove of 18 New Zealand white rabbits and the osteochondral defects were treated with PLGA scaffold (n = 6), PLGA/MSCs (n = 6) or MSC sheet-encapsulated PLGA/MSCs (n = 6). After 6 and 12 weeks, the integration and tissue response were evaluated histologically. RESULTS The MSC sheet-encapsulated PLGA/MCSs group showed significantly more amounts of hyaline cartilage and higher histological scores than PLGA/MSCs group and PLGA group (P < 0.05). In addition, the MSC sheet-encapsulated PLGA/MCSs group showed the best integration between the repaired cartilage and surrounding normal cartilage and subchondral bone compared to other two groups. CONCLUSIONS The novel method of incorporation of MSC sheet to PLGA/MCSs could enhance the ability of cartilage regeneration and integration between repair cartilage and the surrounding cartilage. Transplantation of autologous MSC sheet combined with traditional strategies or cartilage debris might provide therapeutic opportunities for improving cartilage regeneration and integration in humans.
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Skagen PS, Kruse HA, Horn T. Repair Mechanisms in Articular Cartilage—A Porcine in Vitro Study. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/mr.2014.24009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Dai Z, Li K, Chen Z, Liao Y, Yang L, Liu C, Ding W. Repair of avascular meniscal injuries using juvenile meniscal fragments: an in vitro organ culture study. J Orthop Res 2013; 31:1514-9. [PMID: 23813750 DOI: 10.1002/jor.22405] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 05/09/2013] [Indexed: 02/04/2023]
Abstract
We investigated whether the implantation of juvenile allograft and minced meniscal fragments could improve the healing of avascular meniscal injuries, which cannot heal spontaneously. Concentric cylindrical explants were excised from the inner two-thirds of swine medial menisci. The inner cylinder consisted of a "sandwich" structure, with minced juvenile meniscal fragments, juvenile meniscal columns, minced mature meniscal fragments, or mature meniscal columns implanted in the middle. The explants were cultured in vitro for 2, 4, or 6 weeks. Interfacial meniscal repair was assessed by histology, immunohistochemistry, biomechanical testing, and confocal laser scanning microscopy. Histology and confocal microscopy results revealed that tissue repair and cell accumulation at the interface were best at all time points in the juvenile meniscal fragments group, followed by the juvenile columns, minced mature fragments, and mature columns groups, respectively. At 6 weeks, the implantation of juvenile allograft and minced meniscal fragments increased the shear strength, peak force, and energy to failure in the peripheral interface. Picosirius red/polarized light microscopy and immunohistochemistry results showed concurrent expression of type I and II collagen in the interfacial repair tissue. In conclusion, implantation of juvenile allograft and minced meniscal fragments could increase the healing of avascular meniscal injury in vitro.
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Affiliation(s)
- Zhu Dai
- Department of Orthopedics, Xiangya Hospital, Central-South University, 87 Xiangya Road, Changsha, 410078, Hunan, China
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Athens AA, Makris EA, Hu JC. Induced collagen cross-links enhance cartilage integration. PLoS One 2013; 8:e60719. [PMID: 23593295 PMCID: PMC3617163 DOI: 10.1371/journal.pone.0060719] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 03/01/2013] [Indexed: 11/19/2022] Open
Abstract
Articular cartilage does not integrate due primarily to a scarcity of cross-links and viable cells at the interface. The objective of this study was to test the hypothesis that lysyl-oxidase, a metalloenzyme that forms collagen cross-links, would be effective in improving integration between native-to-native, as well as tissue engineered-to-native cartilage surfaces. To examine these hypotheses, engineered cartilage constructs, synthesized via the self-assembling process, as well as native cartilage, were implanted into native cartilage rings and treated with lysyl-oxidase for varying amounts of time. For both groups, lysyl-oxidase application resulted in greater apparent stiffness across the cartilage interface 2–2.2 times greater than control. The construct-to-native lysyl-oxidase group also exhibited a statistically significant increase in the apparent strength, here defined as the highest observed peak stress during tensile testing. Histology indicated a narrowing gap at the cartilage interface in lysyl-oxidase treated groups, though this alone is not sufficient to indicate annealing. However, when the morphological and mechanical data are taken together, the longer the duration of lysyl-oxidase treatment, the more integrated the interface appeared. Though further data are needed to confirm the mechanism of action, the enhancement of integration may be due to lysyl-oxidase-induced pyridinoline cross-links. This study demonstrates that lysyl-oxidase is a potent agent for enhancing integration between both native-to-native and native-to-engineered cartilages. The fact that interfacial strength increased manifold suggests that cross-linking agents should play a significant role in solving the difficult problem of cartilage integration. Future studies must examine dose, dosing regimen, and cellular responses to lysyl-oxidase to optimize its application.
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Affiliation(s)
- Aristos A. Athens
- Department of Biomedical Engineering, University of California Davis, Davis, California, United States of America
- Davis Senior High School, Davis, California, United States of America
| | - Eleftherios A. Makris
- Department of Biomedical Engineering, University of California Davis, Davis, California, United States of America
- Department of Orthopedic Surgery and Musculoskeletal Trauma, University of Thessaly (BIOMED), Larisa, Greece
| | - Jerry C. Hu
- Department of Biomedical Engineering, University of California Davis, Davis, California, United States of America
- * E-mail:
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Cartilage tissue engineering using differentiated and purified induced pluripotent stem cells. Proc Natl Acad Sci U S A 2012; 109:19172-7. [PMID: 23115336 DOI: 10.1073/pnas.1210422109] [Citation(s) in RCA: 181] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The development of regenerative therapies for cartilage injury has been greatly aided by recent advances in stem cell biology. Induced pluripotent stem cells (iPSCs) have the potential to provide an abundant cell source for tissue engineering, as well as generating patient-matched in vitro models to study genetic and environmental factors in cartilage repair and osteoarthritis. However, both cell therapy and modeling approaches require a purified and uniformly differentiated cell population to predictably recapitulate the physiological characteristics of cartilage. Here, iPSCs derived from adult mouse fibroblasts were chondrogenically differentiated and purified by type II collagen (Col2)-driven green fluorescent protein (GFP) expression. Col2 and aggrecan gene expression levels were significantly up-regulated in GFP+ cells compared with GFP- cells and decreased with monolayer expansion. An in vitro cartilage defect model was used to demonstrate integrative repair by GFP+ cells seeded in agarose, supporting their potential use in cartilage therapies. In chondrogenic pellet culture, cells synthesized cartilage-specific matrix as indicated by high levels of glycosaminoglycans and type II collagen and low levels of type I and type X collagen. The feasibility of cell expansion after initial differentiation was illustrated by homogenous matrix deposition in pellets from twice-passaged GFP+ cells. Finally, atomic force microscopy analysis showed increased microscale elastic moduli associated with collagen alignment at the periphery of pellets, mimicking zonal variation in native cartilage. This study demonstrates the potential use of iPSCs for cartilage defect repair and for creating tissue models of cartilage that can be matched to specific genetic backgrounds.
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Dehne T, Zehbe R, Krüger JP, Petrova A, Valbuena R, Sittinger M, Schubert H, Ringe J. A method to screen and evaluate tissue adhesives for joint repair applications. BMC Musculoskelet Disord 2012; 13:175. [PMID: 22984926 PMCID: PMC3732078 DOI: 10.1186/1471-2474-13-175] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 09/12/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Tissue adhesives are useful means for various medical procedures. Since varying requirements cause that a single adhesive cannot meet all needs, bond strength testing remains one of the key applications used to screen for new products and study the influence of experimental variables. This study was conducted to develop an easy to use method to screen and evaluate tissue adhesives for tissue engineering applications. METHOD Tissue grips were designed to facilitate the reproducible production of substrate tissue and adhesive strength measurements in universal testing machines. Porcine femoral condyles were used to generate osteochondral test tissue cylinders (substrates) of different shapes. Viability of substrates was tested using PI/FDA staining. Self-bonding properties were determined to examine reusability of substrates (n = 3). Serial measurements (n = 5) in different operation modes (OM) were performed to analyze the bonding strength of tissue adhesives in bone (OM-1) and cartilage tissue either in isolation (OM-2) or under specific requirements in joint repair such as filling cartilage defects with clinical applied fibrin/PLGA-cell-transplants (OM-3) or tissues (OM-4). The efficiency of the method was determined on the basis of adhesive properties of fibrin glue for different assembly times (30 s, 60 s). Seven randomly generated collagen formulations were analyzed to examine the potential of method to identify new tissue adhesives. RESULTS Viability analysis of test tissue cylinders revealed vital cells (>80%) in cartilage components even 48 h post preparation. Reuse (n = 10) of test substrate did not significantly change adhesive characteristics. Adhesive strength of fibrin varied in different test settings (OM-1: 7.1 kPa, OM-2: 2.6 kPa, OM-3: 32.7 kPa, OM-4: 30.1 kPa) and was increasing with assembly time on average (2.4-fold). The screening of the different collagen formulations revealed a substance with significant higher adhesive strength on cartilage (14.8 kPa) and bone tissue (11.8 kPa) compared to fibrin and also considerable adhesive properties when filling defects with cartilage tissue (23.2 kPa). CONCLUSION The method confirmed adhesive properties of fibrin and demonstrated the dependence of adhesive properties and applied settings. Furthermore the method was suitable to screen for potential adhesives and to identify a promising candidate for cartilage and bone applications. The method can offer simple, replicable and efficient evaluation of adhesive properties in ex vivo specimens and may be a useful supplement to existing methods in clinical relevant settings.
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Affiliation(s)
- Tilo Dehne
- Tissue Engineering Laboratory and Berlin-Brandenburg Center for Regenerative Therapies, Department of Rheumatology and Clinical Immunology, Charité-Universitätsmedizin Berlin, Föhrer Strasse 15, Berlin 13353, Germany.
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Cartilage labelling for mechanical testing in T-peel configuration. INTERNATIONAL ORTHOPAEDICS 2012; 36:1493-9. [PMID: 22237920 DOI: 10.1007/s00264-011-1468-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 12/14/2011] [Indexed: 10/14/2022]
Abstract
PURPOSE The purpose of this study was to find a suitable method of labelling cartilage samples for the measurement of distraction distances in biomechanical testing. METHODS Samples of bovine cartilage were labelled using five different methods: hydroquinone and silver nitrate (AgNO3), potassium permanganate (KMnO4) with sodium thiosulphate (Na2S2O3), India ink, heat, and laser energy. After the labelling, we analysed the cartilage samples with regard to cytotoxity by histochemical staining with ethidiumbromide homodimer (EthD-1) and calcein AM. Furthermore, we tested cartilages labelled with India ink and heat in a T-peel test configuration to analyse possible changes in the mechanical behaviour between marked and unlabelled samples. RESULTS Only the labelling methods with Indian ink or a heated needle showed acceptable results in the cytotoxity test with regard to labelling persistence, accuracy, and the influence on consistency and viability of the chondrocytes. In the biomechanical T-peel configuration, heat-labelled samples collapsed significantly earlier than unlabelled samples. CONCLUSION Labelling bovine cartilage samples with Indian ink in biomechanical testing is a reliable, accurate, inexpensive, and easy-to-perform method. This labelling method influenced neither the biomechanical behaviour nor the viability of the tissue compared to untreated bovine cartilage.
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Theodoropoulos JS, De Croos JNA, Park SS, Pilliar R, Kandel RA. Integration of tissue-engineered cartilage with host cartilage: an in vitro model. Clin Orthop Relat Res 2011; 469:2785-95. [PMID: 21403985 PMCID: PMC3171526 DOI: 10.1007/s11999-011-1856-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND We developed a tissue-engineered biphasic cartilage bone substitute construct which has been shown to integrate with host cartilage and differs from autologous osteochondral transfer in which integration with host cartilage does not occur. QUESTIONS/PURPOSES (1) Develop a reproducible in vitro model to study the mechanisms regulating tissue-engineered cartilage integration with host cartilage, (2) compare the integrative properties of tissue-engineered cartilage with autologous cartilage and (3) determine if chondrocytes from the in-vitro formed cartilage migrate across the integration site. METHODS A biphasic construct was placed into host bovine osteochondral explant and cultured for up to 8 weeks (n = 6 at each time point). Autologous osteochondral implants served as controls (n = 6 at each time point). Integration was evaluated histologically, ultrastructurally, biochemically and biomechanically. Chondrocytes used to form cartilage in vitro were labeled with carboxyfluorescein diacetate which allowed evaluation of cell migration into host cartilage. RESULTS Histologic assessment demonstrated that tissue-engineered cartilage integrated over time, unlike autologous osteochondral implant controls. Biochemically there was an increase in collagen content of the tissue-engineered implant over time but was well below that for native cartilage. Integration strength increased between 4 and 8 weeks as determined by a pushout test. Fluorescent cells were detected in the host cartilage up to 1.5 mm from the interface demonstrating chondrocyte migration. CONCLUSIONS Tissue-engineered cartilage demonstrated improved integration over time in contrast to autologous osteochondral implants. Integration extent and strength increased with culture duration. There was chondrocyte migration from tissue-engineered cartilage to host cartilage. CLINICAL RELEVANCE This in vitro integration model will allow study of the mechanism(s) regulating cartilage integration. Understanding this process will facilitate enhancement of cartilage repair strategies for the treatment of chondral injuries.
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Affiliation(s)
- John S. Theodoropoulos
- Orthopedic Surgery, Mount Sinai Hospital, 600 University Avenue, Suite 476C, Toronto, M5G 1X5 Canada
| | - J. N. Amritha De Croos
- Department of Pathology and Laboratory Medicine, CIHR-BioEngineering of Skeletal Tissues Team, Mount Sinai Hospital, Toronto, Canada
| | - Sam S. Park
- Mount Sinai Hospital, 600 University Avenue, Suite 476C, Toronto, M5G 1X5 Canada
| | - Robert Pilliar
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada
| | - Rita A. Kandel
- Department of Pathology and Laboratory Medicine, CIHR-BioEngineering of Skeletal Tissues Team, Mount Sinai Hospital, Toronto, Canada ,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada
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Vahdati A, Wagner DR. Finite element study of a tissue-engineered cartilage transplant in human tibiofemoral joint. Comput Methods Biomech Biomed Engin 2011; 15:1211-21. [PMID: 21809943 DOI: 10.1080/10255842.2011.585974] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Most tissue-engineered cartilage constructs are more compliant than native articular cartilage (AC) and are poorly integrated to the surrounding tissue. To investigate the effect of an implanted tissue-engineered construct (TEC) with these inferior properties on the mechanical environment of both the engineered and adjacent native tissues, a finite element study was conducted. Biphasic swelling was used to model tibial cartilage and an implanted TEC with the material properties of either native tissue or a decreased elastic modulus and fixed charged density. Creep loading was applied with a rigid impermeable indenter that represented the femur. In comparison with an intact joint, compressive strains in the transplant, surface contact stress in the adjacent native AC and load partitioning between different phases of cartilage were affected by inferior properties of TEC. Results of this study may lead to a better understanding of the complex mechanical environment of an implanted TEC.
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Affiliation(s)
- Ali Vahdati
- Bioengineering Graduate Program, Aerospace and Mechanical Engineering Department, University of Notre Dame, Notre Dame, IN, USA
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Enders JT, Otto TJ, Peters HC, Wu J, Hardouin S, Moed BR, Zhang Z. A model for studying human articular cartilage integration in vitro. J Biomed Mater Res A 2010; 94:509-14. [PMID: 20186769 DOI: 10.1002/jbm.a.32719] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
One of the major obstacles hindering cartilage repair is the integration of the reparative cartilage with the recipient cartilage. The purpose of this study was to develop an in vitro model that can be conveniently applied to simulate and improve the integration of tissue engineered cartilage with native articular cartilage. This model, a cartilage integration construct, consists of a cartilage explant and isolated chondrocytes. The explant was anchored to agarose gel on a culture plate as agarose gelation at 4 degrees C to seal the gap between the bottom of the explant and culture plate surface. Isolated chondrocytes were added and confined in the defect created in the center of the explant. After 4 weeks of culture, neocartilage containing proteoglycans and type II collagen was formed. Minimal integration occurred between the neocartilage and the cartilage explant, resembling the failure of cartilage integration manifested in experimental and clinical cartilage repair. In this model, agarose gel anchors the explant onto culture plate by altering temperatures and effectively prevents "leakage" of the isolated chondrocytes from the defect of the explant. This model provides a convenient simulation of the cartilage integration process in vitro and has applications in studies of cartilage integration and cartilage tissue engineering.
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Affiliation(s)
- J Tyler Enders
- Anatomical Science Program, Saint Louis University, Saint Louis, Missouri, USA
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McNulty AL, Estes BT, Wilusz RE, Weinberg JB, Guilak F. Dynamic loading enhances integrative meniscal repair in the presence of interleukin-1. Osteoarthritis Cartilage 2010; 18:830-8. [PMID: 20202487 PMCID: PMC2872683 DOI: 10.1016/j.joca.2010.02.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Revised: 01/22/2010] [Accepted: 02/06/2010] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Meniscal tears are a common knee injury and increased levels of interleukin-1 (IL-1) have been measured in injured and degenerated joints. Studies have shown that IL-1 decreases the shear strength, cell accumulation, and tissue formation in meniscal repair interfaces. While mechanical stress and IL-1 modulate meniscal biosynthesis and degradation, the effects of dynamic loading on meniscal repair are unknown. The purpose of this study was to determine the effects of mechanical compression on meniscal repair under normal and inflammatory conditions. EXPERIMENTAL DESIGN Explants were harvested from porcine medial menisci. To simulate a full-thickness defect, a central core was removed and reinserted. Explants were loaded for 4h/day at 1 Hz and 0%-26% strain for 14 days in the presence of 0 or 100 pg/mL of IL-1. Media were assessed for matrix metalloproteinase (MMP) activity, aggrecanase activity, sulfated glycosaminoglycan (S-GAG) release, and nitric oxide (NO) production. After 14 days, biomechanical testing and histological analyses were performed. RESULTS IL-1 increased MMP activity, S-GAG release, and NO production, while decreasing the shear strength and tissue repair in the interface. Dynamic loading antagonized IL-1-mediated inhibition of repair at all strain amplitudes. Neither IL-1 treatment nor strain altered aggrecanase activity. Additionally, strain alone did not alter meniscal healing, except at the highest strain magnitude (26%), a level that enhanced the strength of repair. CONCLUSIONS Dynamic loading blocked the catabolic effects of IL-1 on meniscal repair, suggesting that joint loading through physical therapy may be beneficial in promoting healing of meniscal lesions under inflammatory conditions.
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Affiliation(s)
- Amy L. McNulty
- Department of Surgery, Duke University Medical Center, Durham, NC, USA
| | - Bradley T. Estes
- Department of Surgery, Duke University Medical Center, Durham, NC, USA
| | - Rebecca E. Wilusz
- Department of Surgery, Duke University Medical Center, Durham, NC, USA,Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - J. Brice Weinberg
- Department of Medicine, Duke University Medical Center, Durham, NC, USA,VA Medical Center, Durham, NC, USA
| | - Farshid Guilak
- Department of Surgery, Duke University Medical Center, Durham, NC, USA,Department of Biomedical Engineering, Duke University, Durham, NC, USA, Corresponding author: Farshid Guilak, Ph.D., Duke University Medical Center, Box 3093, Durham, NC 27710, Phone (919) 684-2521, Fax (919) 681-8490,
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Sitterle VB, Nishimuta JF, Levenston ME. Photochemical approaches for bonding of cartilage tissues. Osteoarthritis Cartilage 2009; 17:1649-56. [PMID: 19591798 DOI: 10.1016/j.joca.2009.06.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Revised: 03/29/2009] [Accepted: 06/04/2009] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The objective of this study was to evaluate photochemical bonding as an approach for adhering live cartilage tissues across a repair interface in a manner that may lead to enhanced integration. DESIGN Photochemical bonding of both meniscal fibrocartilage and articular cartilage was explored using an anionic, hydrophilic phthalocyanine photosensitizer. Variations on surface preparations and irradiation parameters were explored using overlapped tissue strips and tested using a modified single-lap shear test. Durability of the photochemically induced bonds and cellular viability were examined in an in vitro cartilage defect model for up to 1 week in culture, with bond strength assessed via push-out test. RESULTS Meniscal tissue strips bonded with no surface treatment, but cartilage strips required enzymatic treatment with chondroitinase-ABC to effectively bond. More aggressive removal of glycosaminoglycans at the interface led to increased bond strengths. Bond strength achieved with a 10min irradiation of treated tissue was on the order of that previously achieved through several weeks of culture. In the defect model, photochemical bonds between a tissue annulus and a press-fit tissue core were maintained for 1 week in culture without substantial increases in cell death near the bonded interface. CONCLUSIONS With appropriate treatment parameters, photochemical bonding rapidly produced a stable structural interface between cartilage tissue samples and may be a promising strategy for enhancing initial attachment in cartilage repair strategies.
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Affiliation(s)
- V B Sitterle
- Georgia Tech Research Institute, 250 14th Street, Suite 547, Georgia Institute of Technology, Atlanta, GA 30332-0817, USA
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Gilbert SJ, Singhrao SK, Khan IM, Gonzalez LG, Thomson BM, Burdon D, Duance VC, Archer CW. Enhanced tissue integration during cartilage repair in vitro can be achieved by inhibiting chondrocyte death at the wound edge. Tissue Eng Part A 2009; 15:1739-49. [PMID: 19119922 DOI: 10.1089/ten.tea.2008.0361] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVE Experimental wounding of articular cartilage results in cell death at the lesion edge. The objective of this study was to investigate whether inhibition of this cell death results in enhanced integrative cartilage repair. METHODS Bovine articular cartilage discs (6 mm) were incubated in media containing inhibitors of necrosis (Necrostatin-1, Nec-1) or apoptosis (Z-VAD-FMK, ZVF) before cutting a 3 mm inner core. This core was left in situ to create disc/ring composites, cultured for up to 6 weeks with the inhibitors, and analyzed for cell death, sulfated glycosaminoglycan release, and tissue integration. RESULTS Creating the disc/ring composites resulted in a significant increase in necrosis. ZVF significantly reduced necrosis and apoptosis at the wound edge. Nec-1 reduced necrosis. Both inhibitors reduced the level of wound-induced sulfated glycosaminoglycan loss. Toluidine blue staining and electron microscopy of cartilage revealed significant integration of the wound edges in disc/ring composites treated with ZVF. Nec-1 improved integration, but to a lesser extent. Push-out testing revealed that ZVF increased adhesive strength compared to control composites. CONCLUSIONS This study shows that treatment of articular cartilage with cell death inhibitors during wound repair increases the number of viable cells at the wound edge, prevents matrix loss, and results in a significant improvement in cartilage-cartilage integration.
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Affiliation(s)
- Sophie J Gilbert
- Connective Tissue Biology Laboratories, School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom.
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Pabbruwe MB, Esfandiari E, Kafienah W, Tarlton JF, Hollander AP. Induction of cartilage integration by a chondrocyte/collagen-scaffold implant. Biomaterials 2009; 30:4277-86. [PMID: 19539365 PMCID: PMC2723758 DOI: 10.1016/j.biomaterials.2009.02.052] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2008] [Accepted: 02/03/2009] [Indexed: 10/25/2022]
Abstract
The integration of implanted cartilage is a major challenge for the success of tissue engineering protocols. We hypothesize that in order for effective cartilage integration to take place, matrix-free chondrocytes must be induced to migrate between the two tissue surfaces. A chondrocyte/collagen-scaffold implant system was developed as a method of delivering dividing cells at the interface between two cartilage surfaces. Chondrocytes were isolated from bovine nasal septum and seeded onto both surfaces of a collagen membrane to create the chondrocyte/collagen-scaffold implant. A model of two cartilage discs and the chondrocyte/collagen-scaffold sandwiched in between was used to effect integration in vitro. The resulting tissue was analysed histologically and biomechanically. The cartilage-implant-cartilage sandwich appeared macroscopically as one continuous piece of tissue at the end of 40 day cultures. Histological analysis showed tissue continuum across the cartilage-scaffold interface. The integration was dependent on both cells and scaffold. Fluorescent labeling of implanted chondrocytes demonstrated that these cells invade the surrounding mature tissue and drive a remodelling of the extracellular matrix. Using cell-free scaffolds we also demonstrated that some chondrocytes migrated from the natural cartilage into the collagen scaffold. Quantification of integration levels using a histomorphometric repair index showed that the chondrocyte/collagen-scaffold implant achieved the highest repair index compared to controls, reflected functionally through increased tensile strength. In conclusion, cartilage integration can be achieved using a chondrocyte/collagen-scaffold implant that permits controlled delivery of chondrocytes to both host and graft mature cartilage tissues. This approach has the potential to be used therapeutically for implantation of engineered tissue.
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Affiliation(s)
- Moreica B Pabbruwe
- Stem Cell Biology, Department of Cellular and Molecular Medicine, School of Medical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
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Pei M, He F, Boyce BM, Kish VL. Repair of full-thickness femoral condyle cartilage defects using allogeneic synovial cell-engineered tissue constructs. Osteoarthritis Cartilage 2009; 17:714-22. [PMID: 19128988 DOI: 10.1016/j.joca.2008.11.017] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Accepted: 11/28/2008] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Synovium-derived stem cells (SDSCs) have proven to be superior in cartilage regeneration compared with other sources of mesenchymal stem cells. We hypothesized that conventionally passaged SDSCs can be engineered in vitro into cartilage tissue constructs and the engineered premature tissue can be implanted to repair allogeneic full-thickness femoral condyle cartilage defects without immune rejection. METHODS Synovial tissue was harvested from rabbit knee joints. Passage 3 SDSCs were mixed with fibrin glue and seeded into non-woven polyglycolic acid (PGA) mesh. After 1-month incubation with growth factor cocktails, the premature tissue was implanted into rabbit knees to repair osteochondral defects with Collagraft as a bone substitute in the Construct group. Fibrin glue-saturated PGA/Collagraft composites were used as a Scaffold group. The defect was left untreated as an Empty group. RESULTS SDSCs were engineered in rotating bioreactor systems into premature cartilage, which displayed the expression of sulfated glycosaminoglycan (GAG), collagen II, collagen I, and macrophages. Six months after implantation with premature tissue, cartilage defects were full of smooth hyaline-like cartilage with no detectable collagen I and macrophages but a high expression of collagen II and GAG, which were also integrated with the surrounding native cartilage. The Scaffold and Empty groups were resurfaced with fibrous-like and fibrocartilage tissue, respectively. CONCLUSION Allogeneic SDSC-based premature tissue constructs are a promising stem cell-based approach for cartilage defects. Although in vitro data suggest that contaminated macrophages affected the quality of SDSC-based premature cartilage, effects of macrophages on in vivo tissue regeneration and integration necessitate further investigation.
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Affiliation(s)
- M Pei
- Tissue Engineering Laboratory, Department of Orthopaedics, West Virginia University, Morgantown, WV 26506, USA.
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Sitterle VB, Sun W, Levenston ME. A modified lap test to more accurately estimate interfacial shear strength for bonded tissues. J Biomech 2008; 41:3260-4. [PMID: 18986654 DOI: 10.1016/j.jbiomech.2008.09.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2008] [Revised: 09/03/2008] [Accepted: 09/04/2008] [Indexed: 11/16/2022]
Abstract
Effective attachment to relevant anatomical surfaces has long been a critical issue for tissue replacement or repair. This is especially true for cartilage repair where adequate, reliable initial fixation to surrounding tissue and joint surfaces has been a dominant factor affecting clinical outcomes. Due to ease of application and ability to replicate dimensions and rates across multiple experiments, the single-lap test in tension has become a common method to assess interfacial strength for cartilage and other tissues in apposition. The standard single-lap configuration does not, however, provide a true measure of shear strength. The presence of a bending moment and resulting bond rotation create an uneven stress environment; specimens typically fail due to peel stresses at the edges of the interface. This report describes finite element analysis of variations to the single-lap method in which supports were added to either side of the bond interface. These results were then experimentally validated using photochemically bonded articular cartilage. Both the finite element and experimental results show that the addition of supports helps mitigate edge stresses and produces a more uniform stress distribution across the bond interface. Adding supports to prevent bond rotation, even for specimens not fixed to the supports, still produces a better estimate of shear strength than the traditional, non-supported configuration. These findings allow selection of a single-lap approach to more closely approximate shear strength even in those situations where it is not feasible or otherwise desirable to fix the tissue specimens to supports.
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Rice MA, Homier PM, Waters KR, Anseth KS. Effects of directed gel degradation and collagenase digestion on the integration of neocartilage produced by chondrocytes encapsulated in hydrogel carriers. J Tissue Eng Regen Med 2008; 2:418-29. [DOI: 10.1002/term.113] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Wilusz RE, Weinberg JB, Guilak F, McNulty AL. Inhibition of integrative repair of the meniscus following acute exposure to interleukin-1 in vitro. J Orthop Res 2008; 26:504-12. [PMID: 18050309 PMCID: PMC2729761 DOI: 10.1002/jor.20538] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Damage or loss of the meniscus is associated with progressive osteoarthritic degeneration of the knee joint. Injured and degenerative joints are characterized by elevated levels of the pro-inflammatory cytokine interleukin-1 (IL-1), which with prolonged exposure can induce catabolic and anti-anabolic activities that inhibit tissue repair. We used an in vitro model system to examine the hypotheses that acute exposure to IL-1 inhibits meniscal repair, and that an IL-1-mediated increase in matrix metalloproteinase (MMP) activity is associated with the inhibition of repair. Integrative tissue repair was studied between concentric explants of porcine medial menisci that were treated with IL-1alpha acutely (100 pg/mL for 1 or 3 days) or chronically (100 pg/mL for entire culture duration). After 14 and 28 days in culture, biomechanical testing, cell viability, and histology were performed to assess meniscal repair. Total specific MMP activity in the culture media was measured using a quenched fluorescent substrate. As little as 1 day of IL-1 exposure significantly reduced shear strength, cell accumulation, and tissue repair compared to controls. IL-1 exposure for 1 or 3 days significantly increased MMP activity that subsided by day 9. With chronic IL-1 exposure, MMP activity remained elevated for the duration of culture and was negatively correlated with repair strength. Our study shows that short-term exposure to physiologically relevant concentrations of IL-1 significantly reduces meniscal repair in vitro, and thus may potentially inhibit the intrinsic repair response in vivo. The suppression of IL-1 or MMP expression and/or activity warrant investigation as potential strategies for promoting meniscal repair.
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Affiliation(s)
- Rebecca E. Wilusz
- Department of Surgery, Duke University Medical Center, Department of Biomedical Engineering, Duke University
| | | | - Farshid Guilak
- Department of Surgery, Duke University Medical Center, Department of Biomedical Engineering, Duke University
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Englert C, Blunk T, Müller R, von Glasser SS, Baumer J, Fierlbeck J, Heid IM, Nerlich M, Hammer J. Bonding of articular cartilage using a combination of biochemical degradation and surface cross-linking. Arthritis Res Ther 2008; 9:R47. [PMID: 17504533 PMCID: PMC2206351 DOI: 10.1186/ar2202] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Revised: 04/30/2007] [Accepted: 05/15/2007] [Indexed: 11/10/2022] Open
Abstract
After trauma, articular cartilage often does not heal due to incomplete bonding of the fractured surfaces. In this study we investigated the ability of chemical cross-linkers to facilitate bonding of articular cartilage, either alone or in combination with a pre-treatment with surface-degrading agents. Articular cartilage blocks were harvested from the femoropatellar groove of bovine calves. Two cartilage blocks, either after pre-treatment or without, were assembled in a custom-designed chamber in partial apposition and subjected to cross-linking treatment. Subsequently, bonding of cartilage was measured as adhesive strength, that is, the maximum force at rupture of bonded cartilage blocks divided by the overlap area. In a first approach, bonding was investigated after treatment with cross-linking reagents only, employing glutaraldehyde, 1-ethyl-3-diaminopropyl-carbodiimide (EDC)/N-hydroxysuccinimide (NHS), genipin, or transglutaminase. Experiments were conducted with or without compression of the opposing surfaces. Compression during cross-linking strongly enhanced bonding, especially when applying EDC/NHS and glutaraldehyde. Therefore, all further experiments were performed under compressive conditions. Combinations of each of the four cross-linking agents with the degrading pre-treatments, pepsin, trypsin, and guanidine, led to distinct improvements in bonding compared to the use of cross-linkers alone. The highest values of adhesive strength were achieved employing combinations of pepsin or guanidine with EDC/NHS, and guanidine with glutaraldehyde. The release of extracellular matrix components, that is, glycosaminoglycans and total collagen, from cartilage blocks after pre-treatment was measured, but could not be directly correlated to the determined adhesive strength. Cytotoxicity was determined for all substances employed, that is, surface degrading agents and cross-linkers, using the resazurin assay. Taking the favourable cell vitality after treatment with pepsin and EDC/NHS and the cytotoxic effects of guanidine and glutaraldehyde into account, the combination of pepsin and EDC/NHS appeared to be the most advantageous treatment in this study. In conclusion, bonding of articular cartilage blocks was achieved by chemical fixation of their surface components using cross-linking reagents. Application of compressive forces and prior modulation of surface structures enhanced cartilage bonding significantly. Enzymatic treatment in combination with cross-linkers may represent a promising addition to current techniques for articular cartilage repair.
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Affiliation(s)
- Carsten Englert
- Department of Trauma Surgery, University Medical Centre Regensburg, Franz-Josef-Strauss-Allee, 93053 Regensburg, Germany
| | - Torsten Blunk
- Department of Pharmaceutical Technology, University of Regensburg, Universitätsstrasse, 93053 Regensburg, Germany
| | - Rainer Müller
- Institute of Physical and Theoretical Chemistry, University of Regensburg, Universitätsstrasse, 93053 Regensburg, Germany
| | - Sabine Schulze von Glasser
- Department of Trauma Surgery, University Medical Centre Regensburg, Franz-Josef-Strauss-Allee, 93053 Regensburg, Germany
| | - Julia Baumer
- Department of Pharmaceutical Technology, University of Regensburg, Universitätsstrasse, 93053 Regensburg, Germany
| | - Johann Fierlbeck
- Mechanical Engineering Faculty, University of Applied Sciences, Galgenbergstrasse, 93053 Regensburg, Germany
| | - Iris M Heid
- GSF-National Research Centre, Institute of Epidemiology, Ingolstädter Landstrasse, 85674 Neuherberg, Germany
- Institute of Medical Informatics, Biometry, and Epidemiology, Ludwig-Maximilians-University, Munich, Germany
| | - Michael Nerlich
- Department of Trauma Surgery, University Medical Centre Regensburg, Franz-Josef-Strauss-Allee, 93053 Regensburg, Germany
| | - Joachim Hammer
- Mechanical Engineering Faculty, University of Applied Sciences, Galgenbergstrasse, 93053 Regensburg, Germany
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Abstract
Integration of the host-graft interface is implicated as one of the significant reasons for lack of complete healing in osteochondral grafting procedures for the treatment of cartilage lesions. We developed an in vitro model of cartilage healing in an osteochondral setting to study the effect of developmental age and collagenase treatment. Circular full-thickness vertical surgical incisions were made in the cartilaginous portion of cylindrical bovine osteochondral specimens. Two age groups were selected: Young (1-2 months old) and Older (6-8 months old). Cartilage integration across the surgical incisions was assessed by histologic analysis and by mechanical push-out testing at 2 and 4 weeks in culture. Histologic integration as well as peak push-out shear stress was significantly higher in older calf cartilage than in the young calf. Collagenase pretreatment in the older calf samples increased push-out strength at 4 weeks. Histologic integration correlated well with the mechanical push-out strength. Developmental age and time after injury affected the response to collagenase pretreatment. This osteochondral cartilage integration model can be useful to study factors that modulate healing of surgical replacement procedures in vitro, which may aid the development of newer approaches to promote the healing of cartilage defects.
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Affiliation(s)
- Hok Kei Tam
- Shiley Center for Orthopaedic Research and Education at Scripps Clinic, 11025 North Torrey Pines Road, Suite 140, La Jolla, California 92037, USA
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Hennerbichler A, Moutos FT, Hennerbichler D, Weinberg JB, Guilak F. Interleukin-1 and tumor necrosis factor alpha inhibit repair of the porcine meniscus in vitro. Osteoarthritis Cartilage 2007; 15:1053-60. [PMID: 17448702 PMCID: PMC3217205 DOI: 10.1016/j.joca.2007.03.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Accepted: 03/03/2007] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Injury or removal of the knee meniscus leads to progressive joint degeneration, and current surgical therapies for meniscal tears seek to maximally preserve meniscal structure and function. However, the factors that influence intrinsic repair of the meniscus are not well understood. The goal of this study was to investigate the capacity of meniscus tissue to repair a simulated defect in vitro and to examine the effect of pro-inflammatory cytokines on this process. METHODS Cylindrical explants were harvested from the outer one-third of medial porcine menisci. To simulate a full-thickness defect, a central core was removed and reinserted immediately into the defect. Explants were cultured for 2, 4, or 6 weeks in serum-containing media in the presence or absence of interleukin-1 (IL-1) or tumor necrosis factor alpha (TNF-alpha), and meniscal repair was investigated using mechanical testing and fluorescence confocal microscopy. RESULTS Meniscal lesions in untreated samples showed a significant capacity for intrinsic repair in vitro, with increasing cell accumulation and repair strength over time in culture. In the presence of IL-1 or TNF-alpha, no repair was observed despite the presence of abundant viable cells. CONCLUSIONS This study demonstrates that the meniscus exhibits an intrinsic repair response in vitro. However, the presence of pro-inflammatory cytokines completely inhibited repair. These findings suggest that increased levels of pro-inflammatory cytokines post-injury or under arthritic conditions may inhibit meniscal repair. Therefore, inhibition of these cytokines may provide a means of accelerating repair of damaged or injured menisci in vivo.
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Affiliation(s)
- Alfred Hennerbichler
- Department of Surgery, Division of Orthopaedic Surgery, Duke University Medical Center, Durham, NC 27710, U.S.A
- Department of Trauma Surgery and Sports Medicine Innsbruck Medical University, A-6020 Innsbruck, Austria
| | - Franklin T. Moutos
- Department of Surgery, Division of Orthopaedic Surgery, Duke University Medical Center, Durham, NC 27710, U.S.A
| | - Diana Hennerbichler
- Department of Surgery, Division of Orthopaedic Surgery, Duke University Medical Center, Durham, NC 27710, U.S.A
| | - J. Brice Weinberg
- Department of Medicine VA and Duke Medical Centers, Durham, NC 27705, U.S.A
| | - Farshid Guilak
- Department of Surgery, Division of Orthopaedic Surgery, Duke University Medical Center, Durham, NC 27710, U.S.A
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Englert C, Fierlbeck J, von Glasser SS, Nerlich M, Hammer J. Mechanical characteristics of articular cartilage bonds. Clin Biomech (Bristol, Avon) 2007; 22:849-55. [PMID: 17570569 DOI: 10.1016/j.clinbiomech.2007.04.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2006] [Revised: 04/07/2007] [Accepted: 04/24/2007] [Indexed: 02/07/2023]
Abstract
BACKGROUND Sutures for adaptation of articular cartilage are used in arthritis therapy techniques. However, little is known about the mechanical functionality of these sutures. The objective of the present work was to compare the mechanical properties of articular cartilage bonds either generated by suture, or, alternatively, by chemical cross-linking of the opposing surfaces or in vitro integrative repair of cartilage blocks. METHODS Bonding was achieved by suture in varying numbers, positions and orientations, by surface cross-linking using carbodiimide in combination with pepsin or guanidine (immediate bonding), or by cultivation for 14 days, either with or without testosterone. The mechanical properties of the cartilage bonds were measured under tensile loading. FINDINGS Suture led to the highest maximal load at failure and by far to the highest strain and lowest stiffness of the bonded samples. Immediate bonding by chemical cross-linking in combination with pepsin led to a low force at failure, but the highest stiffness, as compared to all other groups. Cultivation in the presence of testosterone led to a higher force at failure and a higher strain than chemical cross-linking. INTERPRETATION Suture technique for bonding of cartilage surfaces leads to a very elastic adaptation which allows synovial fluid flow in between the interface of cartilage wounds. Long-term bonding of cartilage wounds would be counteracted by a fluid flow through the interface during motion of the joint. Immediate bonding of cartilage wounds by chemical cross-linking reagents might be a useful alternative tool. Even more promising, with regard to the mechanical properties, appears to be integrative repair of cartilage blocks stimulated by testosterone.
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Affiliation(s)
- Carsten Englert
- Department of Trauma Surgery, Regensburg University Medical Center, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany.
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Lee CSD, Gleghorn JP, Won Choi N, Cabodi M, Stroock AD, Bonassar LJ. Integration of layered chondrocyte-seeded alginate hydrogel scaffolds. Biomaterials 2007; 28:2987-93. [PMID: 17382380 DOI: 10.1016/j.biomaterials.2007.02.035] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Accepted: 02/23/2007] [Indexed: 10/23/2022]
Abstract
Motivated by the necessity to engineer appropriately stratified cartilage, the shear mechanics of layered, bovine chondrocyte-seeded 20mg/mL alginate scaffolds were investigated and related to the structure and biochemical composition. Chondrocyte-seeded alginate scaffolds were exposed to a calcium-chelating solution, layered, crosslinked in CaCl(2), and cultured for 10 weeks. The shear mechanical properties of the layered gels were statistically similar to those of the non-layered controls. Shear modulus of layered gels increased by approximately six-fold while toughness and shear strength increased by more than two-fold during the culture period. Hydroxyproline content in both layered gels and controls had statistically significant increases after 6 weeks. Glycosaminoglycan (GAG) content of controls increased throughout culture while GAG content in layered gels leveled off after 4 weeks. Hematoxylin and eosin histological staining showed tissue growth at the interface over the first 4 weeks. Shear mechanical properties in the engineered tissues showed significant correlations to hydroxyproline content. Dependence of interfacial mechanical properties on hydroxyproline content was most evident for layered gels when compared to controls, especially for toughness and shear strength. Additionally, interfacial properties showed almost no dependence on GAG content. These findings demonstrate the feasibility of creating stratified engineered tissues through layering and that collagen deposition is necessary for interfacial integrity.
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Affiliation(s)
- Christopher S D Lee
- Department of Materials Science and Engineering, Cornell University, Bard Hall 214, Ithaca, NY 14853, USA
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Hennerbichler A, Moutos FT, Hennerbichler D, Weinberg JB, Guilak F. Repair response of the inner and outer regions of the porcine meniscus in vitro. Am J Sports Med 2007; 35:754-62. [PMID: 17261570 DOI: 10.1177/0363546506296416] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND The menisci are essential intra-articular structures that contribute to knee function, and meniscal injury or loss is associated with joint degeneration. Tears of the outer vascularized zone have a greater potential for repair than do tears in the inner avascular region. OBJECTIVE AND HYPOTHESIS Develop an in vitro explant model to examine the hypothesis that differences exist in the intrinsic repair response between the outer and inner region of the meniscus. STUDY DESIGN Controlled laboratory study. METHODS Cylindrical explants were harvested from the outer one third and inner two thirds of medial porcine menisci. To simulate a full-thickness defect, a central core was removed and reinserted immediately. Explants were cultured for 2, 4, or 6 weeks, and meniscal healing was investigated using mechanical testing, histologic analysis, and fluorescence confocal microscopy. RESULTS Over the 6-week culture period, meniscal explants exhibited migration of cells into the repair site, followed by increased tissue formation that bridged the interface. The repair strength increased significantly over time, with no differences between the 2 regions. CONCLUSION The findings show that explants from the avascular inner zone and vascular outer zone of the meniscus exhibit similar healing potential and repair strength in vitro. CLINICAL RELEVANCE These findings support the hypothesis that the regional differences in meniscal repair observed clinically are owed to the additional vascular supply of the outer meniscus rather than intrinsic differences between the extracellular matrix and cells from these 2 areas.
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Affiliation(s)
- Alfred Hennerbichler
- Department of Surgery, Division of Orthopaedic Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
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Richmon JD, Sage A, Wong WV, Chen AC, Sah RL, Watson D, Watston D. Compressive biomechanical properties of human nasal septal cartilage. ACTA ACUST UNITED AC 2007; 20:496-501. [PMID: 17063745 DOI: 10.2500/ajr.2006.20.2932] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Nasal septal cartilage is frequently used in nasal reconstruction and is a common source of chondrocytes for cartilage tissue engineering. The biomechanical properties of septal cartilage have yet to be fully defined and this limits the ability to compare it to the various alternative tissue-implant materials or tissue-engineered neocartilage. Given the unique structure and orientation of the septum within the nose, we sought to investigate anisotropic behaviors of septal cartilage in compression and correlate this to the concentration of glycosaminoglycans (GAG) and collagen within the cartilage. METHODS Human nasal septal cartilage specimens were tested in confined compression, with each sample analyzed in a medial orientation and also either a vertical or caudal-cephalic orientation, with the order of tests randomized. The equilibrium confined compression (aggregate) modulus, HAO, and the permeability, kp, at different offset compression levels were obtained for each compression test. After testing, the cartilage samples were solubilized, and the concentrations of GAG and collagen were obtained. RESULTS Forty-nine compression tests (24 medial, 12 vertical, 13 caudal-cephalic) were run on cartilage specimens obtained from 21 patients. There was a significant effect of orientation on compression modulus, HAO, with the vertical (0.7 +/- 0.12 MPa) and caudal-cephalic (0.66 +/- 0.01 MPa) orientations being significantly stiffer (p = 0.05) than the medial orientation (0.44 +/- 0.04 MPa). There was a trend of an orientation effect on kp at 15% offset compression (p = 0.12) and a borderline significant effect of orientation on kp at 30% offset compression (p = 0.05), demonstrating the M orientation to be more permeable than both the vertical and caudal-cephalic orientations. Both univariate and multivariate analysis did not demonstrate a significant effect of order of compression, age, gender, thickness, dry/wet weight, GAG, or collagen on either HAO, or kp values (p > 0.05). CONCLUSION This study provides new information on the compressive properties of septal cartilage along different axes of compression. The results demonstrate that human septal cartilage is anisotropic; the compressive stiffness is higher in the vertical and caudal-cephalic orientations than in the medial orientation. Additionally, the medial orientation tends to have the greatest permeability. The data obtained in this study provide a reference to which various craniofacial reconstruction materials and tissue-engineered neocartilage can be compared.
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Affiliation(s)
- Jeremy D Richmon
- Division of Head and Neck Surgery, University of California, San Diego, and San Diego Veterans Affairs Healthcare System, San Diego, California, 92103, USA.
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McNulty AL, Moutos FT, Weinberg JB, Guilak F. Enhanced integrative repair of the porcine meniscus in vitro by inhibition of interleukin-1 or tumor necrosis factor α. ACTA ACUST UNITED AC 2007; 56:3033-42. [PMID: 17729298 DOI: 10.1002/art.22839] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE To examine the hypotheses that increasing concentrations of interleukin-1 (IL-1) or tumor necrosis factor alpha (TNFalpha) inhibit the integrative repair of the knee meniscus in an in vitro model system, and that inhibitors of these cytokines will enhance repair. METHODS Explants (8 mm in diameter) were harvested from porcine medial menisci. To simulate a full-thickness defect, a 4-mm-diameter core was removed and reinserted. Explants were cultured for 14, 28, or 42 days in the presence of 0-1,000 pg/ml of IL-1 or TNFalpha. Explants were also cultured in the presence of IL-1 or TNFalpha with IL-1 receptor antagonist (IL-1Ra) or TNF monoclonal antibody (mAb). At the end of the culture period, biomechanical testing, cell viability, and histologic analyses were performed to quantify the extent of repair. RESULTS Mechanical testing revealed increased repair strength, cell accumulation, and tissue formation at the interface over time under control conditions. Pathophysiologic concentrations of both IL-1 and TNFalpha significantly decreased repair strength, cell migration, and tissue formation at the interface. The addition of IL-1Ra or TNF mAb to explants prevented the effects of IL-1 or TNFalpha, respectively. CONCLUSION Our findings document that physiologically relevant concentrations of IL-1 and TNFalpha inhibit meniscal repair in vitro and therefore may also inhibit meniscal repair during arthritis or following joint injury. The finding that IL-1Ra and TNF mAb promoted integrative meniscal repair in an inflammatory microenvironment suggests that intraarticular delivery of IL-1Ra and/or TNF mAb may be useful clinically to promote meniscal healing following injury.
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Affiliation(s)
- Amy L McNulty
- Duke University Medical Center, Durham, North Carolina 27710, USA
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Englert C, Blunk T, Fierlbeck J, Kaiser J, Stosiek W, Angele P, Hammer J, Straub RH. Steroid hormones strongly support bovine articular cartilage integration in the absence of interleukin-1β. ACTA ACUST UNITED AC 2006; 54:3890-7. [PMID: 17133597 DOI: 10.1002/art.22250] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Posttraumatic integration of articular cartilage at fracture sites is essential for mechanical stability of cartilage, and ruptured cartilage is a prerequisite for early osteoarthritis. This study was undertaken to investigate effects on articular cartilage integration mediated by steroid hormones, interleukin-1beta (IL-1beta), and combinations thereof. METHODS Articular cartilage blocks were cultured in partial apposition for 2 weeks with ascorbic acid, testosterone, 17beta-estradiol, and dehydroepiandrosterone (DHEA), with or without IL-1beta. Mechanical integration was measured as adhesive strength, i.e., the maximum force at rupture of integrated cartilage blocks divided by the overlap area. Glycosaminoglycan content was used to study synthesized extracellular matrix. RESULTS Culture in medium without supplements did not lead to integration (adhesive strength 0 kPa). With administration of ascorbic acid (100 microg/ml), the median adhesive strength was 49 kPa. In comparison with ascorbic acid alone, all steroid hormones induced a strong, concentration-dependent stimulation of integration (with maximum values observed with DHEA at 3 x 10(-5)M, testosterone at 10(-8)M, and 17beta-estradiol at 10(-11)M). For testosterone and 17beta-estradiol, this was also reflected by an increase of glycosaminoglycan content. Adhesive strength was increased with IL-1beta at 10 pg/ml, but not at 1 pg/ml or 100 pg/ml. In the presence of both IL-1beta and sex hormones, integration of articular cartilage was reduced. CONCLUSION This is the first study to demonstrate that steroid hormones such as 17beta-estradiol, DHEA, and testosterone stimulate articular cartilage integration. This effect is abrogated by low concentrations of IL-1beta. In the absence of IL-1beta or after neutralization of IL-1beta, steroid hormones might be favorable adjuvant compounds to optimize cartilage integration.
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Brehm W, Aklin B, Yamashita T, Rieser F, Trüb T, Jakob RP, Mainil-Varlet P. Repair of superficial osteochondral defects with an autologous scaffold-free cartilage construct in a caprine model: implantation method and short-term results. Osteoarthritis Cartilage 2006; 14:1214-26. [PMID: 16820305 DOI: 10.1016/j.joca.2006.05.002] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2005] [Accepted: 05/09/2006] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To compare four different implantation modalities for the repair of superficial osteochondral defects in a caprine model using autologous, scaffold-free, engineered cartilage constructs, and to describe the short-term outcome of successfully implanted constructs. METHODS Scaffold-free, autologous cartilage constructs were implanted within superficial osteochondral defects created in the stifle joints of nine adult goats. The implants were distributed between four 6-mm-diameter superficial osteochondral defects created in the trochlea femoris and secured in the defect using a covering periosteal flap (PF) alone or in combination with adhesives (platelet-rich plasma (PRP) or fibrin), or using PRP alone. Eight weeks after implantation surgery, the animals were killed. The defect sites were excised and subjected to macroscopic and histopathologic analyses. RESULTS At 8 weeks, implants that had been held in place exclusively with a PF were well integrated both laterally and basally. The repair tissue manifested an architecture similar to that of hyaline articular cartilage. However, most of the implants that had been glued in place in the absence of a PF were lost during the initial 4-week phase of restricted joint movement. The use of human fibrin glue (FG) led to massive cell infiltration of the subchondral bone. CONCLUSIONS The implantation of autologous, scaffold-free, engineered cartilage constructs might best be performed beneath a PF without the use of tissue adhesives. Successfully implanted constructs showed hyaline-like characteristics in adult goats within 2 months. Long-term animal studies and pilot clinical trials are now needed to evaluate the efficacy of this treatment strategy.
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Affiliation(s)
- W Brehm
- Equine Clinic, Department of Clinical Veterinary Medicine, University of Bern, Switzerland.
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Marenzana M, Kelly DJ, Prendergast PJ, Brown RA. A collagen-based interface construct for the assessment of cell-dependent mechanical integration of tissue surfaces. Cell Tissue Res 2006; 327:293-300. [PMID: 17024413 DOI: 10.1007/s00441-006-0316-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Accepted: 08/01/2006] [Indexed: 10/24/2022]
Abstract
The interface between any newly engineered tissue and pre-existing tissue is of great importance to tissue engineering; however, this process has so far been largely ignored, with few reports regarding the mechanical strength of newly integrated connective tissues surfaces. A new model system has been developed to generate a well-defined interface between two collagen lattices: one pre-contracted by resident fibroblasts and the other a cell-free wrapping gel. This construct can be cultured for prolonged periods (>2 weeks) and can also be fitted onto a mechanical testing system to measure the interface adhesive strength at the end of the culture time. Interface adhesive strength shows a six-fold increase after 1 week in culture, compared with the time-zero baseline. Observations of cell migration across the interface suggest that cell translocation in the three-dimensional matrix might play an important role in the integration process. In this new controlled geometry, normal and shear stresses at the interface can be analysed by finite element modelling and the areas at which debonding starts can be defined. The current experimental design permits solid multiple (homogeneous or heterogeneous) interface formation in vitro with a well-defined geometry and the possibility of measuring mechanical linkage. This design should enable many other factors affecting cell-driven interface strengthening to be investigated.
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Affiliation(s)
- M Marenzana
- RFUCMS, Tissue Repair and Engineering Centre, Institute of Orthopaedics, Stanmore Campus, University College London, Brockley Hill, Stanmore, UK
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Janssen LM, In der Maur CD, Bos PK, Hardillo JA, van Osch GJVM. Short-duration enzymatic treatment promotes integration of a cartilage graft in a defect. Ann Otol Rhinol Laryngol 2006; 115:461-8. [PMID: 16805379 DOI: 10.1177/000348940611500611] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES Surgical manipulation of cartilage tissue is associated with chondrocyte death in the wound edges that hinders integration. The objective of this study was to evaluate the effect of a short course of treatment of a cartilage graft with a combination of hyaluronidase and collagenase on chondrocyte density and integrative capacity. METHODS Cartilage explants were treated with enzymes for various time periods and at various concentrations. A central core was punched out of a larger explant, treated with enzymes, reimplanted, and placed subcutaneously in athymic mice. The number of chondrocytes in the wound edges was counted, and the integrative capacity of the grafts was evaluated by histology. RESULTS Treatment with collagenase for 48 hours led to a significant increase in the number of vital chondrocytes and restored it to normal after 14 days of culture. Treatment with hyaluronidase and collagenase for 48 hours further increased chondrocyte densities to supranormal values. Shortening the treatment to 1 hour restored the chondrocyte density to normal after 14 days of culture. In vivo integration experiments showed increased chondrocyte densities in treated wound edges and extracellular matrix fibers crossing over from enzyme-treated parts to untreated parts. CONCLUSIONS Short-duration treatment of a cartilage graft with a combination of hyaluronidase and collagenase increases cell density at wound edges and promotes integrative repair.
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Affiliation(s)
- Luuk M Janssen
- Department of Otorhinolaryngology, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, The Netherlands
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Miyakoshi N, Kobayashi M, Nozaka K, Okada K, Shimada Y, Itoi E. Effects of intraarticular administration of basic fibroblast growth factor with hyaluronic acid on osteochondral defects of the knee in rabbits. Arch Orthop Trauma Surg 2005; 125:683-92. [PMID: 16189685 DOI: 10.1007/s00402-005-0052-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2004] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Growth factors including basic fibroblast growth factor (bFGF) are expected to be useful tools for enhancing osteochondral repair. However, suitable carriers are required to deliver a growth factor to the injury site. We evaluated the effects of intraarticular injection of bFGF with hyaluronic acid (HA) on osteochondral repair and the potential carrier role of HA in this treatment. MATERIALS AND METHODS Osteochondral defect was created in the medial femoral condyle of rabbits and received single or weekly intraarticular injection of bFGF (1 or 10 microg) with or without HA. Prior to the administration, bFGF was incubated with HA or vehicle-saline for 24 h at 4 degrees C. Four weeks after the initial injection, the animals were killed and the defect was evaluated grossly (12-point scale) and histologically (16-point scale). The effect of single injection of bFGF (1 microg) with HA was also compared to that of the carrier known as gelatin microspheres (GM) incorporating bFGF. RESULTS Weekly-administered bFGF alone induced undesirable side effects such as inflammatory responses and osteophyte formation. However, weekly-administered 1 mug of bFGF with HA yielded significantly better osteochondral repair than each treatment alone in gross and histological examinations with minimal side effects (P < 0.05). Single administration of 1 microg bFGF with HA but not GM incorporating bFGF showed significantly better osteochondral repair comparing to the vehicle control (P < 0.05). CONCLUSION Low-dose bFGF with HA was effective for osteochondral repair in rabbits. The significant osteochondral reparative role of bFGF with HA comparing with GM incorporating bFGF might be explained by the potential carrier role of HA and possible synergistic action between these two agents. The combination of HA with bFGF significantly suppressed the side effects resulting from single use of bFGF.
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Affiliation(s)
- Naohisa Miyakoshi
- Department of Orthopedic Surgery, Akita University School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan.
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Moretti M, Wendt D, Schaefer D, Jakob M, Hunziker EB, Heberer M, Martin I. Structural characterization and reliable biomechanical assessment of integrative cartilage repair. J Biomech 2005; 38:1846-54. [PMID: 16023472 DOI: 10.1016/j.jbiomech.2004.08.021] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2004] [Indexed: 10/26/2022]
Abstract
Structural and functional characterization of integrative cartilage repair in controlled model systems can play a key role in the development of innovative strategies to improve the long-term outcome of many cartilage repair procedures. In this work, we first developed a method to reproducibly generate geometrically defined disk/ring cartilage composites and to remove outgrown fibrous layers which can encapsulate cartilaginous tissues during culture. We then used the model system to test the hypothesis that such fibrous layers lead to an overestimation of biomechanical parameters of integration at the disk/ring interface. Transmission electron microscopy images of the composites after 6 weeks of culture indicated that collagen fibrils in the fibrous tissue layer were well integrated into the collagen network of the cartilage disk and ring, whereas molecular bridging between opposing disk/ring cartilage surfaces was less pronounced and restricted to regions with narrow interfacial regions (< 2 microm). Stress-strain profiles generated from mechanical push-out tests for composites with the layers removed displayed a single and distinct peak, whereas profiles for composites with the layers left intact consisted of multiple superimposed peaks. As compared to composites with removed layers, composites with intact layers had significantly higher adhesive strengths (161+/-9 vs. 71+/-11 kPa) and adhesion energies (15.0+/-0.7 vs. 2.7+/-0.4 mJ/mm2). By combining structural and functional analyses, we demonstrated that the outgrowing tissue formed during in vitro culture of cartilaginous specimens should be eliminated in order to reliably quantify biomechanical parameters related to integrative cartilage repair.
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Affiliation(s)
- M Moretti
- Department of Surgery, Institute for Surgical Research and Hospital Management, University Hospital Basel, Hebelstrasse 20, ZLF, Room 405, 4031 Basel, Switzerland
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Tognana E, Padera RF, Chen F, Vunjak-Novakovic G, Freed LE. Development and remodeling of engineered cartilage-explant composites in vitro and in vivo. Osteoarthritis Cartilage 2005; 13:896-905. [PMID: 16019238 DOI: 10.1016/j.joca.2005.05.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2004] [Accepted: 05/04/2005] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Development and remodeling of engineered cartilage-explant composites were studied in vitro and in vivo. DESIGN Individual and interactive effects of cell chondrogenic potential (primary or fifth passage bovine calf chondrocytes), scaffold degradation rate (hyaluronan benzyl ester or polyglycolic acid), and adjacent tissue cell activity and architecture (vital trabecular bone (VB), articular cartilage (AC), devitalized bone (DB) or digested cartilage (DC)) were evaluated over 8 weeks in vitro (bioreactor cultures) and in vivo (ectopic implants). RESULTS In vitro, significant effects of cell type on construct adhesive strength (P<0.001) and scaffold type on adhesive strength (P<0.001), modulus (P=0.014), glycosaminoglycans (GAG) (P<0.001), and collagen (P=0.039) were observed. Chondrogenesis was best when the scaffold degradation rate matched the extracellular matrix deposition rate. In vivo, adjacent tissue type affected adhesive strength (P<0.001), modulus (P<0.001), and GAG (P<0.001) such that 8-week values obtained for bone (VB and DB) were higher than for cartilage (AC). In the AC/construct group, chondrogenesis appeared attenuated in the region of the construct close to the AC. In contrast, in the VB/construct group, a 500 microm thick zone of mature hyaline-like cartilage formed at the interface, and signs of active remodeling were present in the bone that included osteoclastic and osteoblastic activity and trabecular rebuttressing; these features were not present in the DB group or in vitro. CONCLUSIONS Development and remodeling of composites based on engineered cartilage were mediated in vitro by cell chondrogenic potential and scaffold degradation rate, and in vivo by type of adjacent tissue and time.
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Affiliation(s)
- Enrico Tognana
- Division of Health Sciences and Technology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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Ahsan T, Harwood F, McGowan KB, Amiel D, Sah RL. Kinetics of collagen crosslinking in adult bovine articular cartilage. Osteoarthritis Cartilage 2005; 13:709-15. [PMID: 16043034 DOI: 10.1016/j.joca.2005.03.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2004] [Revised: 03/20/2005] [Accepted: 03/22/2005] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Determine the kinetics of collagen crosslinking in adult bovine articular cartilage explants using radiolabel pulse-chase studies. METHODS Explant cultures of adult bovine articular cartilage were radiolabeled with [14C]lysine in medium including fetal bovine serum and ascorbate, and then maintained for chase periods up to 28 days. In some samples, beta-aminopropionitrile (BAPN) was included during chase to inhibit lysyl oxidase-mediated collagen crosslinking. Tissue was hydrolyzed and analyzed for [14C]metabolites in the forms of lysine, hydroxylysine, dehydrodihydroxylysinonorleucine (DeltaDHLNL), and hydroxylysyl pyridinoline (HP). RESULTS Explant cultures of adult bovine articular cartilage metabolized lysine into hydroxylysine and the collagen crosslinks, DeltaDHLNL and HP. During chase, [14C]hydroxylysine maintained steady-state levels, [14C]DHLNL rose to a plateau, and [14C]HP increased gradually. Addition of BAPN inhibited formation of [14C]DHLNL. Analysis of raw data and that normalized to [14C]hydroxylysine gave characteristic time constants for formation of DeltaDHLNL and HP crosslinks of 1-2 and 7-30 days, respectively. The distribution of [14C]lysine metabolites in collagen crosslinks was described by peak values in [14C]DHLNL/[14C]hydroxylysine of 0.047-0.064 and in [14C]HP/[14C]hydroxylysine of 0.03. CONCLUSION Collagen crosslinks form in cartilage explants in vitro according to the classical lysyl oxidase-mediated pathway.
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Affiliation(s)
- T Ahsan
- Department of Bioengineering, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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Dorotka R, Windberger U, Macfelda K, Bindreiter U, Toma C, Nehrer S. Repair of articular cartilage defects treated by microfracture and a three-dimensional collagen matrix. Biomaterials 2005; 26:3617-29. [PMID: 15621252 DOI: 10.1016/j.biomaterials.2004.09.034] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2004] [Accepted: 09/21/2004] [Indexed: 12/19/2022]
Abstract
The objective of our study was to evaluate the behavior of ovine chondrocytes and bone marrow stromal cells (BMSC) on a matrix comprising type-I, -II, and -III collagen in vitro, and the healing of chondral defects in an ovine model treated with the matrix, either unseeded or seeded with autologous chondrocytes, combined with microfracture treatment. For in vitro investigation, ovine chondrocytes and BMSC were seeded on the matrix and cultured at different time points. Histological analysis, immunohistochemistry, biochemical assays for glycosaminoglycans, and real-time quantitative PCR for collagens were performed. The animal study described here included 22 chondral defects in 11 sheep, divided into four treatment groups. Group A: microfracture and collagen matrix seeded with chondrocytes; B: microfracture and unseeded matrices; C: microfracture; D: untreated defects. All animals were sacrificed 16 weeks after implantation, and a histomorphometrical and qualitative evaluation of the defects was performed. The in vitro investigation revealed viable cells up to 3 weeks; chondrocytes had a predominantly round morphology, produced glycosaminoglycans, and expressed both collagen markers, whereas BMSC stained positive for antibodies against type-II collagen; however, no mRNA for type-II collagen was amplified. All treatment groups of the animal model showed better defect filling compared to untreated knees. The cell-seeded group had the greatest quantity of repair tissue and the largest quantity of hyaline-like tissue. Although the collagen matrix is an adequate environment for BMSC in vitro, the additionally implanted unseeded collagen matrix did not increase the repair response after microfracture in chondral defects. Only the matrices seeded with autologous cells in combination with microfracture were able to facilitate the regeneration of hyaline-like cartilage.
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Affiliation(s)
- R Dorotka
- Department of Orthopaedic Surgery, Medical School, University of Vienna, Waehringer Guertel 18-20, A-1090 Wien, Austria
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Englert C, McGowan KB, Klein TJ, Giurea A, Schumacher BL, Sah RL. Inhibition of integrative cartilage repair by proteoglycan 4 in synovial fluid. ACTA ACUST UNITED AC 2005; 52:1091-9. [PMID: 15818696 DOI: 10.1002/art.20986] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To determine the effects of the articular cartilage surface, as well as synovial fluid (SF) and its components, specifically proteoglycan 4 (PRG4) and hyaluronic acid (HA), on integrative cartilage repair in vitro. METHODS Blocks of calf articular cartilage were harvested, some with the articular surface intact and others without. Some of the latter types of blocks were pretreated with trypsin, and then with bovine serum albumin, SF, PRG4, or HA. Immunolocalization of PRG4 on cartilage surfaces was performed after treatment. Pairs of similarly treated cartilage blocks were incubated in partial apposition for 2 weeks in medium supplemented with serum and (3)H-proline. Following culture, mechanical integration between apposed cartilage blocks was assessed by measuring adhesive strength, and protein biosynthesis and deposition were determined by incorporated (3)H-proline. RESULTS Samples with articular surfaces in apposition exhibited little integrative repair compared with samples with cut surfaces in apposition. PRG4 was immunolocalized at the articular cartilage surface, but not in deeper, cut surfaces (without treatment). Cartilage samples treated with trypsin and then with SF or PRG4 exhibited an inhibition of integrative repair and positive immunostaining for PRG4 at treated surfaces compared with normal cut cartilage samples, while samples treated with HA exhibited neither inhibited integrative repair nor PRG4 at the tissue surfaces. Deposition of newly synthesized protein was relatively similar under conditions in which integration differed significantly. CONCLUSION These results support the concept that PRG4 in SF, which normally contributes to cartilage lubrication, can inhibit integrative cartilage repair. This has the desirable effect of preventing fusion of apposing surfaces of articulating cartilage, but has the undesirable effect of inhibiting integrative repair.
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Affiliation(s)
- Carsten Englert
- University of California, San Diego, La Jolla 92093-0412, USA
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McGowan KB, Sah RL. Treatment of cartilage with beta-aminopropionitrile accelerates subsequent collagen maturation and modulates integrative repair. J Orthop Res 2005; 23:594-601. [PMID: 15885480 DOI: 10.1016/j.orthres.2004.02.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/11/2004] [Indexed: 02/04/2023]
Abstract
Integrative repair of cartilage was previously found to depend on collagen synthesis and maturation. beta-aminopropionitrile (BAPN) treatment, which irreversibly blocks lysyl oxidase, inhibited the formation of collagen crosslinks, prevented development of adhesive strength, and caused a buildup of GuHCl-extractable collagen crosslink precursors. This buildup of crosslink precursor in the tissue may be useful for enhancing integrative repair. We tested in vitro the hypothesis that pre-treatment of cartilage with BAPN, followed by washout before implantation, could be a useful therapeutic strategy to accelerate subsequent collagen maturation. In individual cartilage disks, collagen processing was reversibly blocked by BAPN treatment (0.1 mM) as indicated by a BAPN-induced increase in the total and proportion of incorporated radiolabel that was extractable by 4M guanidine-HCl, followed by a decrease, within 3-4 days of BAPN washout, in the proportion of extractable radiolabel to control levels. With a similar pattern, integration between pairs of apposed cartilage blocks was reversibly blocked by BAPN treatment, and followed by an enhancement of integration after BAPN washout. The low and high levels of integration were associated with enrichment in [(3)H]proline in a form that was susceptible and resistant, respectively, to extraction. With increasing duration up to 7 days after BAPN pre-treatment, the levels of [(3)H]proline extraction decreased, and the development of adhesive strength increased. Thus, BAPN can be used to modulate integrative cartilage repair.
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Affiliation(s)
- Kevin B McGowan
- Department of Bioengineering, Whitaker Institute of Biomedical Engineering, University of California-San Diego, La Jolla, 92093-0412, USA
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Tognana E, Chen F, Padera RF, Leddy HA, Christensen SE, Guilak F, Vunjak-Novakovic G, Freed LE. Adjacent tissues (cartilage, bone) affect the functional integration of engineered calf cartilage in vitro. Osteoarthritis Cartilage 2005; 13:129-38. [PMID: 15694574 DOI: 10.1016/j.joca.2004.10.015] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2004] [Accepted: 10/22/2004] [Indexed: 02/02/2023]
Abstract
OBJECTIVE An in vitro model was used to test the hypothesis that culture time and adjacent tissue structure and composition affected chondrogenesis and integrative repair in engineered cartilage. METHOD Engineered constructs made of bovine calf chondrocytes and hyaluronan benzyl ester non-woven mesh were press-fitted into adjacent tissue rings made of articular cartilage (AC), devitalized bone (DB), or vital bone (VB) and cultured in rotating bioreactors for up to 8 weeks. Structure (light and electron microscopy), biomechanical properties (interfacial adhesive strength, construct compressive modulus), biochemical composition (construct glycosaminoglycans (GAG), collagen, and cells), and adjacent tissue diffusivity were assessed. RESULTS Engineered constructs were comprised predominately of hyaline cartilage, and appeared either closely apposed to adjacent cartilage or functionally interdigitated with adjacent bone due to interfacial deposition of extracellular matrix. An increase in culture time significantly improved construct adhesive strength (P<0.001), modulus (P=0.02), GAG (P=0.04) and cellularity (P<0.001). The type of adjacent tissue significantly affected construct adhesion (P<0.001), modulus (P<0.001), GAG (P<0.001) and collagen (P<0.001). For constructs cultured in rings of cartilage, negative correlations were observed between ring GAG content (log transformed) and construct adhesion (R2=0.66, P<0.005), modulus (R2=0.49, P<0.05) and GAG (R2=0.44, P<0.05). Integrative repair was better for constructs cultured adjacent to bone than cartilage, in association with its solid architectural structure and high GAG content, and best for constructs cultured adjacent to DB, in association with its high diffusivity. CONCLUSIONS Chondrogenesis and integrative repair in engineered cartilage improved with time and depended on adjacent tissue architecture, composition, and transport properties.
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Affiliation(s)
- E Tognana
- Division of Health Sciences & Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Gratz KR, Wong VW, Chen AC, Fortier LA, Nixon AJ, Sah RL. Biomechanical assessment of tissue retrieved after in vivo cartilage defect repair: tensile modulus of repair tissue and integration with host cartilage. J Biomech 2004; 39:138-46. [PMID: 16271598 DOI: 10.1016/j.jbiomech.2004.10.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2004] [Accepted: 10/22/2004] [Indexed: 11/20/2022]
Abstract
Failure to restore the mechanical properties of tissue at the repair site and its interface with host cartilage is a common problem in tissue engineering procedures to repair cartilage defects. Quantitative in vitro studies have helped elucidate mechanisms underlying processes leading to functional biomechanical changes. However, biomechanical assessment of tissue retrieved from in vivo studies of cartilage defect repair has been limited to compressive tests. Analysis of integration following in vivo repair has relied on qualitative histological methods. The objectives of this study were to develop a quantitative biomechanical method to assess (1) the tensile modulus of repair tissue and (2) its integration in vivo, as well as determine whether supplementation of transplanted chondrocytes with IGF-I affected these mechanical properties. Osteochondral blocks were obtained from a previous 8 month study on the effects of IGF-I on chondrocyte transplantation in the equine model. Tapered test specimens were prepared from osteochondral blocks containing the repair/native tissue interface and adjacently located blocks of intact native tissue. Specimens were then tested in uniaxial tension. The tensile modulus of repair tissue averaged 0.65 MPa, compared to the average of 5.2 MPa measured in intact control samples. Integration strength averaged 1.2 MPa, nearly half the failure strength of intact cartilage samples, 2.7 MPa. IGF-I treatment had no detectable effects on these mechanical properties. This represents the first quantitative biomechanical investigation of the tensile properties of repair tissue and its integration strength in an in vivo joint defect environment.
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Affiliation(s)
- Kenneth R Gratz
- Department of Bioengineering, University of California-San Diego, 9500 Gilman Drive, Mail Code 0412, La Jolla, CA 92093-0412, USA
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Johnson TS, Xu JW, Zaporojan VV, Mesa JM, Weinand C, Randolph MA, Bonassar LJ, Winograd JM, Yaremchuk MJ. Integrative Repair of Cartilage with Articular and Nonarticular Chondrocytes. ACTA ACUST UNITED AC 2004; 10:1308-15. [PMID: 15588391 DOI: 10.1089/ten.2004.10.1308] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Articular chondrocytes can synthesize new cartilaginous matrix in vivo that forms functional bonds with native cartilage. Other sources of chondrocytes may have a similar ability to form new cartilage with healing capacity. This study evaluates the ability of various chondrocyte sources to produce new cartilaginous matrix in vivo and to form functional bonds with native cartilage. Disks of articular cartilage and articular, auricular, and costal chondrocytes were harvested from swine. Articular, auricular, or costal chondrocytes suspended in fibrin glue (experimental), or fibrin glue alone (control), were placed between disks of articular cartilage, forming trilayer constructs, and implanted subcutaneously into nude mice for 6 and 12 weeks. Specimens were evaluated for neocartilage production and integration into native cartilage with histological and biomechanical analysis. New matrix was formed in all experimental samples, consisting mostly of neocartilage integrating with the cartilage disks. Control samples developed fibrous tissue without evidence of neocartilage. Ultimate tensile strength values for experimental samples were significantly increased (p < 0.05) from 6 to 12 weeks, and at 12 weeks they were significantly greater (p < 0.05) than those of controls. We conclude that articular, auricular, and costal chondrocytes have a similar ability to produce new cartilaginous matrix in vivo that forms mechanically functional bonds with native cartilage.
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Affiliation(s)
- Timothy S Johnson
- Division of Plastic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02130, USA
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Improved cartilage integration and interfacial strength after enzymatic treatment in a cartilage transplantation model. Arthritis Res Ther 2004; 6:R469-76. [PMID: 15380046 PMCID: PMC546287 DOI: 10.1186/ar1216] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2004] [Revised: 05/30/2004] [Accepted: 06/23/2004] [Indexed: 11/10/2022] Open
Abstract
The objective of the present study was to investigate whether treatment of articular cartilage with hyaluronidase and collagenase enhances histological and mechanical integration of a cartilage graft into a defect. Discs of 3 mm diameter were taken from 8-mm diameter bovine cartilage explants. Both discs and annulus were either treated for 24 hours with 0.1% hyaluronidase followed by 24 hours with 10 U/ml collagenase or left untreated (controls). Discs and annulus were reassembled and implanted subcutaneously in nude mice for 5 weeks. Integration of disc with surrounding cartilage was assessed histologically and tested biomechanically by performing a push-out test. After 5 weeks a significant increase in viable cell counts was seen in wound edges of the enzyme-treated group as compared with controls. Furthermore, matrix integration (expressed as a percentage of the total interface length that was connected; mean ± standard error) was 83 ± 15% in the treated samples versus 44 ± 40% in the untreated controls. In the enzyme-treated group only, picro-Sirius Red staining revealed collagen crossing the interface perpendicular to the wound surface. Immunohistochemical analyses demonstrated that the interface tissue contained cartilage-specific collagen type II. Collagen type I was found only in a small region of fibrous tissue at the level of the superficial layer, and collagen type III was completely absent in both groups. A significant difference in interfacial strength was found using the push-out test: 1.32 ± 0.15 MPa in the enzyme-treated group versus 0.84 ± 0.14 MPa in the untreated controls. The study shows that enzyme treatment of cartilage wounds increases histological integration and improves biomechanical bonding strength. Enzymatic treatment may represent a promising addition to current techniques for articular cartilage repair.
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Hunter CJ, Levenston ME. Maturation and Integration of Tissue-Engineered Cartilages within anin VitroDefect Repair Model. ACTA ACUST UNITED AC 2004; 10:736-46. [PMID: 15265290 DOI: 10.1089/1076327041348310] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This study compared the behavior of four different engineered cartilages in a hybrid culture system. First, the growth and maturation of tissue-engineered cartilages in isolation were compared to those grown in an in vitro articular cartilage defect repair model. Tissue-engineered cartilages using fibrin, agarose, or poly(glycolic acid) scaffolds were implanted into annular explants of articular cartilage and cultured for 20 or 40 days. Native tissue had a substantial influence on the DNA, sulfated glycosaminoglycan, and hydroxyproline content of the engineered tissues, suggesting that the presence of living tissue in the culture significantly altered cell proliferation and matrix accumulation. Second, the adhesion strength of various engineered cartilages to native tissue was measured and compared with the biochemical content of the engineered tissues. All scaffold treatments adhered to the native cartilage, but there were statistically significant differences in adhesive strength between the different scaffolds. The adhesive strength of all engineered scaffolds was significantly lower than that of native tissue to itself. In the engineered tissues, neither failure stress nor energy to failure correlated with gross biochemical content, suggesting that adhesion between native and engineered tissues is not purely a function of gross matrix synthesis.
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Affiliation(s)
- Christopher J Hunter
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405, USA
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